Nr2en2022 by Univ Petr

A JOURNAL OF MINING AND ENVIRONMENT

Vol. 28 Issue 2 / 2022 ISSN-L 1220-2053 / ISSN 2247-8590

Universitas Publishing Petroșani, Romania

REVISTA MINELOR - MINING REVUE A JOURNAL OF MINING AND ENVIRONMENT

Editorial board Editor in chief: Prof. Ilie ONICA Managing editors: Assoc.prof. Andrei ANDRAS Assoc.prof. Paul Dacian MARIAN Editorial advisory board: Prof. Dumitru FODOR Prof. Nicolae ILIAŞ Prof. Mircea GEORGESCU Prof. Pascu Mihai COLOJA Language editor: Lect. Lavinia HULEA Technical editor: Radu ION

ISSN-L 1220-2053 ISSN 2247-8590 www.upet.ro/revistaminelor www.sciendo.com/journal/MINRV

Scientiﬁc committee: Prof. Iosif ANDRAȘ, University of Petrosani, Romania PhD. Eng. Marwan AL HEIB, Ecole des mines de Nancy, INERIS, France Assist. prof. Adam BAJCAR, Poltegor-Instytut, Poland PhD. Eng. Iosif Horia BENDEA, Politechnico di Torino, Italy Assoc. prof. Boyko BEROV, Bulgarian Academy of Sciences, Bulgaria Prof. Essaid BILAL, Centre Sciences des Processus Industriels et Naturels (SPIN), France Prof. Lucian BOLUNDUȚ, University of Petrosani, Romania Prof. Ioan BUD, Technical University of Cluj-Napoca (North Center of Baia Mare), Romania Prof. Nam BUI, Hanoi University of Science and Technology, Vietnam PhD. Eng. Constantin Sorin BURIAN, INSEMEX Petrosani, Romania Prof. Eugen COZMA, University of Petrosani, Romania PhD. Eng. György DEÁK, National Institute for Research and Development in Environmental Protection Prof. Nicolae DIMA, University of Petrosani, Romania Prof. Carsten DREBENSTEDT, TU Bergakademie Freiberg, Germany Prof. Ioan DUMITRESCU, University of Petrosani, Romania PhD. Eng. George-Artur GĂMAN, INSEMEX Petrosani, Romania Prof. Ioan GÂF-DEAC, Dimitrie Cantemir Christian University Bucharest, Romania Ph.D. Eng. Edmond GOSKOLLI, National Agency of Natural Resources, Albania Prof. Andreea IONICĂ, University of Petrosani, Romania Prof. Sair KAHRAMAN, Hacettepe University, Turkey Prof. Sanda KRAUSZ, University of Petrosani, Romania Prof. Krzysztof KOTWICA, AGH University of Science and Technology Krakow, Poland Prof. Maria LAZAR, University of Petrosani, Romania Prof. Monica LEBA, University of Petrosani, Romania Prof. Roland MORARU, University of Petrosani, Romania PhD. Eng. Vlad Mihai PĂSCULESCU, INSEMEX Petrosani, Romania Prof. Sorin Mihai RADU, University of Petrosani, Romania Prof. Ilie ROTUNJANU, University of Petrosani, Romania Prof. Mihaela TODERAȘ, University of Petrosani, Romania Assoc. prof. Sorin Silviu UDUBAȘA, University of Bucharest, Romania Prof. Ioel VEREȘ, Technical University of Cluj-Napoca, Romania Assoc. prof. Zoltan Istvan VIRÁG, University of Miskolc, Hungary Prof. Florin Dumitru POPESCU, University of Petrosani, Romania

© Copyright by UNIVERSITAS Publishing House Petroşani / Revista Minelor - Mining Revue published quarterly Editorial contact: Ilie ONICA, e-mail: onicai2004@yahoo.com, phone: 0040 729 066 723 Dacian-Paul MARIAN, e-mail: dacianmarian@upet.ro, phone: 0040 748 130 633 University of Petroşani, 20 Universităţii str., 332006 Petroşani, Romania Phone +40254 / 542.580, fax. +40254 / 543.491 Printed by University of Petroşani Printing Department

Vol. 2 / 2022 ISSN-L 1220-2053 / ISSN 2247-8590

UNIVERSITAS PUBLISHING Petroșani, Romania

CONTENTS

Mihaela TODERAȘ Finite element method for designing large section underground works by sequential excavation method. Study case: Lugoj-Deva road tunnel

Adina BUD Determinations and interpretations of the contents of heavy metals from food and water test samples from locations near the mining perimeters of Baia Mare and Băiuț area

Eugen TRAISTĂ, Camelia TRAISTĂ Research regarding iron sludge recovery technology

Edmond GOSKOLLI New challenges to the deep development of the Bulqiza chrome mines

Jorgaq THANAS, Aida BODE, Sokol MATI Mineral waste, recycling and rehabilitation of their disposal areas

Ioan-Lucian BOLUNDUȚ Gold: properties, minerals, alloys, uses and recycling

Ofelia-Larisa FILIP, Anca Daniela FILIP Analysis of orientation accuracies in underground polygonal routes

Daniela FURDUI (PEAGU), Sorin Mihai RADU Methodology for quantifying the risk of occupational accident and / or disease specific to complex technical systems

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FINITE ELEMENT METHOD FOR DESIGNING LARGE SECTION UNDERGROUND WORKS BY SEQUENTIAL EXCAVATION METHOD. STUDY CASE: LUGOJ-DEVA ROAD TUNNEL Mihaela TODERAȘ1* 1

Mining Engineering, Surveying and Civil Engineering Department, University of Petrosani, Petrosani, Romania, toderasmihaela@yahoo.com

DOI: 10.2478/minrv-2022-0008 Abstract: Any underground work requires the knowledge and application of appropriate techniques and technologies in all stages of implementation of such a project. An important problem in the design of underground works is the knowledge of the characteristics and behaviour of the massif in which the work will be carried out. It depends on the choice of the excavation solution appropriate to the existing real conditions, which will influence the duration of the work and the costs associated with it. The objective of this paper was to analyse and compare the total deformations of the contour of the underground work, assuming that the work is performed by sequential excavation method (S.E.M.): excavation in the horizontal direction and in the vertical direction. The finite element numerical simulation method was used for the convergence analysis, which showed that the total displacements of the tunnel gallery wall are smaller for the horizontal sequential excavation (SEM) variant, both for the hypothesis of coefficient of pressure in state of rest having the value K0 = 0.6, as well as for the hypothesis in which K0 = 2.27. Keywords: sequential excavation method (S.E.M.), finite element method, underground work, deformation, convergence-shrinkage, rock-support interaction, coefficient of pressure 1. Introduction Underground works are a special category in the field of construction, their specificity being given primarily by the fact that they are performed in a natural environment, which is often very little known. Geological and hydrogeological conditions are the determining factors of the degree of difficulty and the cost of carrying out an underground work. At the same time, the underground works require paying special attention to the importance of the study of subsoil reconnaissance, due to the existence of very strong interactions between: geology and geotechnical characteristics of the site on the one hand and the conception and definition of the work to be constructed, respectively the choice and application of the appropriate method of execution, on the other hand. The geomechanical characterization of rock or soil massifs allows obtaining the information necessary to establish their behaviour during the execution and exploitation of the work, defining the execution methods, sizing the works, particular protection measures and / or special consolidation methods that should be considered during the realization of an underground work. An important factor that influences the stability of underground works is the cross section of the work. In the case of large section underground works, such as tunnels, there is a very high risk during construction by sub-excavation, especially in the case of soft or weak ground [1-8]. At the same time, due to the limitation or modification of the characteristics of the underground space, the stability can be negatively influenced due to the interaction between the twin tunnels. The sequential excavation method (SEM) was first developed in Austria and it is a conceived method to be applied to the construction of tunnels in rock massifs. This method, known in particular as the New Austrian Tunnelling Method (NATM), is based on understanding the behaviour of the rock massif that reacts when its equilibrium is disturbed by excavating an underground work. The method of excavation in successive stages

Corresponding author: Mihaela Toderaș, Prof.Ph.D / Mining Engineering, Surveying and Civil Engineering Department, University of Petrosani, Petrosani, Romania (University of Petrosani, 20 University Street, +40741501143, toderasmihaela@yahoo.com) *

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allows to make the most of the participation of the land that supports an important part of the geostatic load. Basically, the rock is decompressed during successive excavations, the confinement pressure in the final stage being reduced on average by 1/4 or 1/3 of the initial pressure. This important phenomenon underlies NATM. The method consists in the combined support of the tunnel with anchors and projected concrete, namely shotcrete, a support method which, according to all the findings made, has a high efficiency. This method uses a light support to take over the deformations of the rock massif. Through this methodology, instead of simply supporting the rock massif disturbed by the execution of an underground work, it allows the massif to support itself, in other words, the rock itself is the one that participates in the support [9 - 11]. If a controlled convergence is considered, the anchor - shotcrete system and possibly welded panels or metal fibres will cause a redistribution of stresses in the rock massif and therefore a stable equilibrium. The peculiarity of the New Austrian Tunnelling Method (NATM) is the use of a combined support, made of perforated anchors (active or passive) and quick-setting shotcrete, from the combination of the two resulting a light support of the massif, to take over the deformations: active anchors or prestressed anchors - solid or wired rods, their fixing being done by injections of cement milk or synthetic resins; passive anchors (punctuated or distributed); the shotcrete has a role of protection and formation of a thin wall that follows the geometry of the ground, is applied immediately after jowling the side walls and will usually be reinforced with fiberglass or metal fibres and wire mesh [9, 11-13]. For the design of the Niayesh urban road tunnel in a massif with poor characteristics (soft ground) and given the large section of the underground work, Sharifzadeh et al. (2013) considered the sequential excavation method, so that in the construction phase of the tunnel the central diaphragm (DC) method and the side wall displacement (SD) method have been proposed; it has also been shown that surface subsidence and tunnel convergence can be effectively controlled [9]. One of the important factors in carrying out a large section underground work by sequential excavation method is the temporary support [2, 6, 7, 11, 13-16]. The finite element numerical simulation method was used to determine the displacements and loads acting on the temporary support [15], based on the geological parameters of the future tunnel location. The purpose of this paper is to analyse and compare the total deformations of the twin tunnels on the Lugoj-Deva road tunnel, in the hypothesis of performing the work by sequential excavation method (SEM) excavation in the horizontal direction and vertical direction. The stability was analysed by the convergenceshrinkage method with the Rocscience software, RocSupport module. The behaviour simulation of the tunnel in three-dimensional space was performed using the Rocscience software, by the finite element method (FEM). 2. Engineering context The Lugoj - Deva Lot 2 road tunnel, section E2 from km 52 + 880 to km 56 + 220, is part of the PanEuropean Corridor IV, which crosses the Romania territory from Nădlac to Constanța. The road tunnel section is located in the western part of the country, in the Banat region and has a total length of 3,214 km. The two road tunnels with double gallery are provided between km 52 + 875 and km 53 + 215: The first tunnel with a length L = 340.0 m and km 53 + 640 - km 54 + 502; the second tunnel with a length L = 744.20 m, having a longitudinal profile development of 1,084.20 m. The Lot 2 route of the Lugoj-Deva road tunnel has an approximate length of 28,600 km and is oriented in the West-East direction (figure 1). The longitudinal profile of the route is presented in figure 2. In the transversal profile, the road tunnel presents geometric elements corresponding to a design speed of 120 km/h, being in accordance with the provisions of PD 162-2002.

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Figure 1. Location of the tunnel a) and its satellite image b)

Figure 2. Longitudinal profile

According to PD 162-2002, for the types of tunnels on the road tunnel, the minimum width of the road between the edges will be 11.50 m and the gauge of free vertical passage of 5.00 m (figure 3); in terms of size, the road tunnel has a radius of R = 6.90 m, and in terms of the excavated gallery has a width of D = 16.00 m and a height of H = 14.00 m.

Figure 3. Typical cross section for road tunnels

From a geomorphological point of view, the studied region is represented by a hilly area, with altitudes between 200 and 400 m. Morphologically, this area is part of the general appearance of the hilly terrain and valleys. From a geological point of view, the region in which the researched location belongs to the Pannonian Depression, being framed by the Getic domain with a predominantly mountainous character in its southern 3

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and central part, determined by the crystalline and eruptive formations of Retezat, Tarcu and Poiana Rusca mountains. The elevated areas are bordered in the west, northwest and east parts by intermountain basins with hilly relief, slightly accentuated, corresponding to tertiary sedimentary formations. Most of the geological formations of the Getic canvas belong to the Southern Carpathians. In the northern part are also included the southern endings of the Apuseni Mountains (Drocea and Metaliferi Mountains). The oldest formations belong to the Proterozoic and Paleozoic; they are widespread and are mainly represented by crystalline schists and granitoid rocks, which make up the mountainous areas of Retezat, Tarc, Poiana Rusca and Semenic. These formations are distributed from the tectonic point of view to the autochthonous Danube and Getic, respectively, the two tectonic units of the area to which we refer. There are tectonic relations between the formations of the two domains, the Getic domain being decked over the Danube one. Epimetamorphic and granitoid crystalline formations, attributed to the Upper Proterozoic - Lower Paleozoic, poorly metamorphosed Paleozoic deposits and Mesozoic sedimentary formations, take part in the composition of the autochthonous Danube, which constitutes Retezat and part of the Ţarcu mountains. The Getic crystalline formations consist of metamorphic schists (prior to the Upper Proterozoic) that make up the southern half of the Poiana Rusca massif, the north-western part of the Tartar and Semenic mountains and epimetamorphic schists (attributed to the Upper Proterozoic and Lower Paleozoic) the northern half of the Poiana Rusca. The mesometamorphic crystalline schist of the Getic domain are well represented in the Poiana Ruscă massif, in its southern part; they also appear in the NW part of the Ţarcu Mountains and in the N part of the Semenic Mountains. The Mesozoic sedimentary deposits belong to the Rusca Montană - Lunca Cernii basin (Barremian Danian) and the Metaliferi mountains (Neocomian, Vraconian-Cenomanian and Turonian-Cognac sedimentary deposits as well as basic Mesozoic eruptive rocks belonging to the initial alpine magmatism). During the Neogene, the sedimentation basins of Lugoj, Caransebeș, Mureș, Strei-Hațeg were formed, by sinking the older formations along some fracture systems. The marine series of the Upper Miocene represents a special importance through the extremely rich fossiliferous deposits from Buituri, Coștei, Lapugiu-Delinești. The Badenian formations, transgressively arranged over various pre-Miocene terms, present a wide development on the slopes of the Mureș between the localities of Deva - Lăpugi – Coștei, consisting of a wide range of lithology (breccias, conglomerates, gravels, sands, marls, clayey marls, coal debris, limestone, gypsum, and pyroclastite). The basal horizon consists of breccias, conglomerates, clayey marls sometimes reddish, over which a psephitic complex follows and often red or grey clays with green spots; the succession continues with the marly facies made up of grey marls, with intercalations of sandstones, sandy clayey marls, with a poor paleontological content. The lagoon facies has the widest extent and is represented by gravels, in which, at various levels, lenses of sandstones and conglomerate banks appear, then an alternation of micaceous grey marls, shale clays with radiolarians, coal clays, sometimes even intercalations of 5- 10 cm of coal, coarse tuff and gypsum. The Pannonian deposits complete the succession of Neogene sedimentary formations. The two horizons (lower - consisting of sandy clay blue or greenish-gray clays with irregular intercalations of sands, sometimes coarse, with lenses of gravel and fragments of coal, and the upper - consisting of sands with gravels and rare clay horizons), lie discordantly over the Tortonian formations, or over the crystalline schists. The Quaternary formations consist of: glacial deposits, proluvial deposits, deluvial-proluvial with reddish clays and alluvial deposits, belonging to the terraces and being attributed to the Pleistocene. The Lower Holocene is attributed to the fluvial deposits of the low terrace made of gravel and sand, and the Upper Holocene is attributed to the recent alluvium of meadows, made of sand and gravel. Neozoic magmatism is represented by tufa sedimentary rocks, tuffs, pyroclastites, lava flows, vein bodies, nekuri and pillars, with varied petrographic composition mainly andesitic. The products of Neozoic volcanism are widespread in the Bulza - Lăpugiu - Sîrbi area where they are mainly represented by pyroclastites and subordinated by bodies and flows of andesitic lavas. These products cross or are arranged over the older antepannonian formations, and are transgressive covered by Pannonian deposits, the main phase of placement being placed in Sarmatian. The oldest Neogene eruptive rocks are represented by rhyolites and rhyolite tuffs, which occur at Pojoga and north of Tomești. From a hydrogeological point of view, the researched area is part of the Pannonian and Quaternary sedimentary complex in the alluvial plain of the river Bega. Its foundation consists of alternating clays and marls with sand intercalations (Pannonian), being covered by Quaternary deposits represented by fine and coarse alluvium (gravel, sand, clay, dust). The water was intercepted at the contact between the deluvial and eluvial deposits with the basic formations made of clays and marls, at depths between 9.70 m and 12.90 m, the quasi-stabilized level being at depths between 7.60 m and 12.90 m. 4

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3. Numerical simulation method 3.1. Pre-dimensioning of the tunnel support by the convergence- shrinkage analytical method Digging a tunnel changes the stress and deformation state of the massif in which the underground work is performed [8, 10, 12, 14, 15, 17]. This new state of tension and deformation is manifested with a different intensity from the initial state, much higher and with the development of radial and tangential stresses, whose value depends on the size of the underground excavation, the depth at which it is executed and the physical – mechanical characteristics of rocks massif. However, the response of rock massif in which the underground work is carried out also depends on the method of excavation and support of the underground work. The excavation process takes place in time and space, and the redistribution of the initial stress state in the massif and the rock-support interaction are also phenomena that evolve as the excavation progresses. The computation of the supports for the studied tunnel was performed by the Duncan Fama method based on the Mohr-Coulomb failure criterion. The geomechanical parameters of the rock are shown in Table 1. Table 1. Geomechanical parameters of the rock considered in computation

Considered parameter Modulus of elasticity, E (MPa) Uniaxial compressive strength, rc (MPa) Internal friction angle, φ (degrees) Coefficient of Poisson, μ

Value 2,000 1.2 15 0.37

The convergence-shrinkage method was performed with the Rocscience software, the RocSupport calculation module. The main support of the tunnel gallery consisted of the following (figures 4 - 5): - EXX Swellex anchors located at a distance of 1.00 m x 1.00 m; - 150 mm thickness of shotcrete with uniaxial compressive strength (UCS) at 28 days of 35 MPa. The obtained results for fixing the support at a distance of 2.00 m behind the front of the tunnel gallery are presented graphically and as a value in section 4.

Figure 4. Tunnel section according to the convergence-shrinkage diagram, safety factor 2.77 and K0 = 2.27

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Figure 5. Tunnel section according to the convergence-shrinkage diagram, probability of failure 0%, safety factor 2.77 and K0 = 2.27

3.2. Sequential excavation method Establishing an optimal, safe, substantiated scientifically solution is one of the important issues in designing and carrying out underground work; this solution must also be economically appropriate. For large cross-sections of underground works, such as tunnels, the optimal solution for carrying out these works is to divide the area of the work into sections that are excavated separately, figure 6 [1].

Figure 6. Sequential partition of planar excavation (according to Wu and Huang, 2020)

The sequential excavation method (S.E.M.) is a method that offers flexibility in the geometry and size of the tunnel cross section. In general, the cross section has an ovoid shape for a uniform redistribution of stress state of the massif around the new created gallery [1, 2, 6, 7, 13, 16]. By adjusting the construction stages, mainly the length of the excavation step, the type of support and the time period until the mounting of the support, the sequential excavation method allows the realization of tunnels in rock and soil massif. Depending on the size of the gallery section and the quality of the rocks or soil in the massif, the excavated section of the tunnel can be divided into several galleries [18], figure 7.

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Figure 7. Sequential excavation in the vertical direction (Svoboda & Masin, 2010)

The sequential excavation method (S.E.M.) involves the following: classification of rocks or soils in the massif, the type of excavation and the supports based on field investigations; defining the excavation and the types of support (maximum length of unsupported excavation; methods of supporting the gallery (shotcrete and reinforcement with anchors and bolts); dividing the cross section of the tunnel into multiple areas as needed; umbrella-type supports in the portal area; if necessary, the operation of supplementing or, as the case may be, thickening the support can be performed locally); instrumentation and monitoring; measures to improve the rock or soil massif in front of the unit face. The important element in the support is the shotcrete or the projected concrete. Guniting, as part of the initial support system, contributes significantly to the mobilization of rock around the underground work. This mobilization can be achieved by controlling the deformations that occur in rocks. Shotcrete is an active support, involving the rock in the process of taking over the pressure that manifests itself on the contour [19]. The shotcrete is capable of filling cracks and allows for continuous support of the tunnel gallery. The instrumentation elements of the sequential excavation method consist in monitoring the deformations of the tunnel and the area around it, allowing the evaluation of the design hypotheses and the adjustment of the tunnel realization process. The shape of the tunnel cross section must be designed in accordance with the principles of the sequential excavation method (SEM). Thus, as far as possible, the vault effect should be created around the excavation to self-support the excavated gallery. Thus, the profile of the tunnel will be curvilinear at both the vault and the hearth (if the tunnel is made in soil massif). Straight or broken lines for the tunnel walls in cross section shall be avoided. Therefore, the geometry of the excavation cross section will be able to take over and redistribute the stress state from the rock/soil massif around the tunnel gallery, minimizing the action of stresses loading on the tunnel supports. The shape of the inverted vault will depend on the geomechanical conditions of the massif in which the tunnel is made. In competent rock formations, the inverted vault will be flat (straight), while in rocks of medium strength (or altered) and in soils the inverted vault of the tunnel will be circular (curvilinear) to facilitate the closure of the annular section and ensure the stability. 3.3. Tunnel modelling by the finite element method Modelling by numerical analysis of the tunnel was performed using Rocscience software. The type of analysis was the deformation in plan, by the finite element method (FEM). The simulation of the behaviour of the tunnel gallery in three-dimensional space (3D) was performed by establishing several excavation stages in the plan. Each excavation stage was assigned a decreasing value of the modulus of elasticity (Young), relative to the value of the modulus of elasticity in situ (Core Replacement Technique - Material Softening). The Mohr - Coulomb failure criterion was used for the design, for a plastic material. The mechanical characteristics of the massif in which the tunnel was designed are shown centrally in Table 2.

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Table 2. The mechanical characteristics of the massif in which the tunnel was designed

Type material

Volumetric weight (MN/m3)

Young modulus (MPa)

Poisson’s coefficient

0.027 0.027

2000 2500

0.37 0.37

Overlying rock Base rock

Internal angle of friction Φ’ (degrees) 10 15

Cohesion, c’ (MPa) 0.05 0.08

Due to the fact that the thickness of the overlying rocks located above the keystone of the tunnel vault is relatively small, and the sedimentary rocks have low geomechanical characteristics, it means that the natural equilibrium vault of the excavated gallery cannot be formed. In order to support the vault of the tunnel gallery and to redistribute the stresses from the massif, prior to the beginning of the excavation, on the contour of the vault of the tunnel gallery it was considered necessary to apply an “umbrella” type support (table 3). Table 3. Characteristics of the "umbrella" type support

"Umbrella" type support Anchors

Diameter (mm)

Length (m)

Tensile strength (MPa) 0.1

Young modulus (MPa) 200000

A reverse vault (reinforced concrete tunnel invert) with the characteristics presented in table 4 was designed in the floor of the tunnel gallery. Table 4. Characteristics of the tunnel floor support

Reinforced concrete reverse vault (tunnel invert) Concrete Reinforcement

Compressive strength (MPa)

Thickness (m)

Poisson’s coefficient

Young modulus (MPa)

40 400

1.20 -

0.15 0.25

35000 200000

4. Results and discussions The analytical method for approximating the stability of the tunnel gallery was performed by the convergence- shrinkage method. The calculation of the elastic supports for the studied tunnel was made by the Duncan Fama method, which is based on the Mohr - Coulomb failure criterion. The main support of the tunnel gallery consisted of EXX Swellex anchors and shotcrete. The obtained results for fixing the support at a distance of 2.00 m behind the front of the tunnel gallery, in the short and long term, are presented in Figure 8 and Table 5.

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Figure 8. Diagrams of the rock massif - support system interaction Table 5. Obtained results by convergence - shrinkage method of the short-term and long-term:

Determined parameter Short term Short-term stability factor (F.S.) Shrinkage pressure mobilized in the short term, MPa Radius of the plastic zone rp, m without support with support Convergence of unsupported tunnel without support gallery, % with support in the short term Failure probability of tunnel wall, % Final displacement of the gallery wall in the short term up, mm Extrusion at the front of the tunnel, mm Support displacement, mm 9

Value 2.77 0.36 15.94 12.05 0.33 0.18 0 12.30 6.95 8.57

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Long-term stability factor (F.S.) Shrinkage pressure mobilized in the long term, MPa Final displacement of the gallery wall in the long term up, mm Convergence of tunnel with long-term support, % Convergence at the tunnel front, % Convergence to support,%

1.59 0.65 15.08 0.22 0.1 0.12

Tunnel modelling by numerical analysis, finite element method (F.E.M.) was performed in the hypothesis of the coefficient of pressure in state of rest K 0 = 0.6 and K0 = 2.27. The results of the tunnel modelling by finite element method (FEM) are shown in Figures 9-16 and Table 6.

Figure 9. The total displacement Δ = 0.0150692 m at the end of the excavation of gallery no. 1 in the horizontal direction, K0 = 2.27

Figure 10. The total displacement Δ = 0.0218594 m at the end of the excavation of gallery no. 2 in the horizontal direction, K0 = 2.27 10

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Figure 11. The total displacement Δ = 0.0113519 m at the end of the excavation of gallery no. 1 in the horizontal direction, K0 = 0.6

Figure 12. The total displacement Δ = 0.0223706 m at the end of the excavation of gallery no. 2 in the horizontal direction, K0 = 0.6

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Figure 13. The total displacement Δ = 0.0240946 m at the end of the excavation of gallery no. 1 in the vertical direction, K0 = 2.27

Figure 14. The total displacement Δ = 0.0287756 m at the end of the excavation of gallery no. 2 in the vertical direction, K0 = 2.27

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Figure 15. The total displacement Δ = 0.0177912 m at the end of the excavation of gallery no. 1 in the vertical direction, K0 = 0.6

Figure 16. The total displacement Δ = 0.0311547 m at the end of the excavation of gallery no. 2 in the vertical direction, K0 = 0.6 Table 6. Total displacement of the tunnel gallery wall

Coefficient of pressure in state of rest K0 =0.6 K0 =2.27 0.0113519 0.0150692 0.0223706 0.0218594 Coefficient of pressure in state of rest K0 =0.6 K0 =2.27 0.0240946 0.0177912 0.0287756 0.0311547

S.E.M. in horizontal direction Gallery no. 1 – total displacement, Δ (m) Gallery no. 1 – total displacement, Δ (m) S.E.M. in vertical direction Gallery no. 1 – total displacement, Δ (m) Gallery no. 1 – total displacement, Δ (m)

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By analysing the obtained values, it is found that the total displacements around the tunnel gallery are smaller for the S.E.M. horizontal direction, both for the hypothesis of the coefficient of pressure in state of rest having the value K0 = 0.6, and for the hypothesis in which K0 = 2.27. 5. Conclusions In order to limit the very large deformations in the rock mass around the tunnel, it was considered that the best solution under the given conditions is to use the sequential excavation method. The instrumentation elements of the sequential excavation method consist in monitoring the deformations of the tunnel and the area around it, allowing the evaluation of the design hypotheses and the adjustment of the execution process of the tunnel. The shape of the tunnel cross section must be designed in accordance with the principles of the sequential excavation method (SEM). Thus, the aim is to create an arch or vault effect around the excavation to support the excavated gallery. Thus, the cross section of the tunnel will be curvilinear at both the vault and the floor (if the tunnel is executed in soils). Straight or broken lines for the tunnel walls in cross section shall be avoided. In this way, the geometry of the excavation cross section will be able to take over and redistribute the stress state from the rock massif around the tunnel gallery, minimizing the action of loading the efforts on the supports of the tunnel. The shape of the inverted vault will depend on the geomechanical conditions of the rock massif in which the tunnel is made. In competent rock formations, the inverted vault (tunnel floor) will have a flat (straight) shape, while in rocks with medium strength (or weathered) rocks and in soils the inverted vault of the tunnel will be curvilinear to facilitate the closure of the annular section and ensure stability. It is proposed that the main support of the tunnel gallery to be done with 5.00 m long anchors, with the distance between the anchors of 1.00 - 1.20 m, reinforced concrete support with a thickness of over 15.00 cm and light metal support at a distance of 1.50 m. The main support of the tunnel gallery will be fixed at approximately 0.50 - 1.00 m behind the face of the excavated gallery. The key support element is the support in shotcrete or projected concrete, because it is able to fill the free spaces and cracks on the contour of the work; this type of support is a continuous support of the tunnel gallery. The peculiarity of the support made of shotcrete or sprayed concrete consists in the participation of the rocks themselves to achieve the load-bearing capacity. Thus, the rocks, from the object of support, become themselves a mean of support, practically the rocks are self-supporting. In the new formed shotcrete - rock system, the last one has a decisive role in supporting the underground works.

References [1] Bo Wu and Wei Huang, 2020 Optimization of sequential excavation method for large-section urban subway tunnel: A case study. Advances in Mechanical Engineering 2020, Vol. 12(9) 1–13. https://doi.org/10.1177/1687814020957185 [2] Vojtech Gall, Nasri Munfah, Design Guidelines for Sequential Excavations Method (SEM) Practices for Road Tunnels in the United States. https://www.gzconsultants.com/wp-content/uploads/Design-Guidelines-for-Sequential-excavation-Method-SEMPractices-for-Road-Tunnels-in-the-United-States-3.pdf [3] Hoek, E., 2001 Big tunnel in bad rock. J. Geotech. Geoenviron. Eng. 127 (9), 726–740. [4] Pierpaolo O., 2009 The Convergence – Confinement Method: Roles and limits in modern geomechanical tunnel design; in American Journal of Applied Sciences 6 (4): 757 – 771. [5] Romero, V., 2002 NATM in soft-ground: a contradiction of terms? Views on NATM and its application to soft-ground tunneling dispelling some misconceptions about this sometimes controversial. World Tunneling, 15, 338-344. [6] Yongtao Yang, Guanhua Sun, Hong Zhenga, Yi Qi, 2019 Investigation of the sequential excavation of a soil-rock-mixture slope using the numerical manifold method. Engineering Geology. Elsevier. Volume 256, 5 June 2019, Pages 93-109. https://doi.org/10.1016/j.enggeo.2019.05.005

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[7] Yongtao Yang, Yinghao Sun, Guanhua Sun, Hong Zhenga, 2020 Sequential excavation analysis of soil-rock-mixture slopes using an improved numerical manifold method with multiple layers of mathematical cover systems. Engineering Geology. Volume 261, 1 November 2019, Elsevier. https://doi.org/10.1016/j.enggeo.2019.105278 [8] Zheng A, Huang F, Tang Z, et al., 2020 Stability analysis of neighborhood tunnels with large section constructed in steeply jointed rock mass. Math Probl Eng 2020; 2020:1–14. [9] Sharifzadeh, M., Kolivand, F., Ghorbania, M., Yasrobi, S., 2013 Design of sequential excavation method for large span urban tunnels in soft ground – Niayesh tunnel. Tunnelling and Underground Space Technology. Volume 35, April 2013, Elsevier, Pages 178-188. https://doi.org/10.1016/j.tust.2013.01.002 [10] Toderaş, M., 2014 Mecanica rocilor, pământurilor şi construcţii subterane. Editura Universitas, Petroşani, ISBN 978-973-741-381-9. [11] Toderaş, M., 2021 Constructii miniere subterane. Vol. I – II, Editura Universitas, Petroşani, ISBN 978-973-741-806-7. [12] Barton N., 1995 Permanent support for tunnels using NMT. In Korean Rock Mechanics Society. [13] Marcher, T., Cordes, T., Bergmeiste, K., 2019 Sequential excavation method – Single shell lining application for the Brenner Base Tunnel. Chapter in book Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art. eBook ISBN 9780429424441 [14] Chapman D. et al, 2010 Introduction to tunnel construction (applied geotechnics). [15] Luo, Yanbin; Chen, Jianxun; Wang, Hongyu; Sun, Penglei, 2017 Deformation rule and mechanical characteristics of temporary support in soil tunnel constructed by sequential excavation method. KSCE Journal of Civil Engineering (2017) 21(6):2439-2449. Tunnel Engineering. DOI 10.1007/s12205-016-0978-3. pISSN 1226-7988, eISSN 1976-3808. www.springer.com/12205 [16] Rana Muhammad Asad Khan, Zaka Emad, Byung Wan Jo, 2017 Tunnel Portal Construction using Sequential Excavation Method: A Case Study. MATEC Web of Conferences 138, 04002 (2017) EACEF 2017. DOI: 10.1051/matecconf/201713804002 [17] Panet M. et al, 2001, The convergence – confinement method. AFTES. [18] Svoboda T. and Masın D., 2010 Convergence – confinement method for simulating NATM tunnels evaluated by comparison with full 3D simulations. [19] Toderas, M., Danciu, C., 2020 Safety, health and hazards related to using of sprayed concrete in underground mining works. 9th International Symposium on Occupational Health and Safety. SESAM 2019, Petroşani, Romania, DOI: https://doi.org/10.1051/matecconf/202030500067. MATEC Web of Conferences - Volume 305 (2020).

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DETERMINATIONS AND INTERPRETATIONS OF THE CONTENTS OF HEAVY METALS FROM FOOD AND WATER TEST SAMPLES FROM LOCATIONS NEAR THE MINING PERIMETERS OF BAIA MARE AND BĂIUȚ AREA Adina BUD1* 1

University of Petrosani, Petrosani, Romania, bud.adina@yahoo.com

DOI: 10.2478/minrv-2022-0009 Abstract: The paper presents the level of heavy metal contamination in the areas located in the vicinity of the mining perimeters in Baia Mare and Băiuț and the risk of their expansion in the future. Heavy metal contamination was analysed on water samples from wells, plants and milk from animals that consumed water from polluted streams. Keywords: heavy metals, sample, contamination, mining perimeters 1. Introduction The monitoring carried out in the recent years on the mining perimeters in Maramureș County revealed that the pollution sources are becoming more and more reactive, proving the amplifying effect of acid drainage. Also, new sources that release pollutants in the environment have been identified, either by destroying some dams or underground diversions, or by the untimely release of the precipitate accumulated on the mine drainage routes. The amount of toxic material released into rivers is constantly increasing, leading to the contamination of some areas in continuous expansion. The impact of heavy metals on the environment and the health of the population has been studied in detail and published in numerous specialized articles. For Baia Mare area, many studies, projects, grants have been carried out, being financed by both national and international authorities [1], [2], [3], [4], [5], [6], [7], [8]. Baia Mare has a long history of heavy metal and toxic gas pollution, being the subject of study and interest for the media, NGOs, various organizations, etc. All these publications referred to the mining activity, but mainly to the metallurgical activity, being considered the main source of pollution. The paper presents the level of heavy metal contamination in the areas located near the mining perimeters of Baia Mare and Băiuț and the risk of their expansion. 2. Sampling and determination of heavy metals in Baia Mare and Băiuț area The paper [8] presents the results of analyzes on water and sediment samples in the vicinity of mining perimeters (emissaries that are directly related to them). The aim of this paper is to assess the level of contamination of groundwater in the area of influence of mining perimeters and possibly contaminated food. With this in view, two types of locations were chosen for study. The first location is next to Tăuții de Sus tailings pond, which is apparently not in the direction of the groundwater flow. In this area, the metal content of a well located at a distance of 87 m from the pond was determined with the groundwater level in the hay at a depth of 5 m. The analyzes were performed in the laboratory of SC Vital SA. The paper highlighted the effects of bioaccumulation of heavy metals in the food chain. In accordance, food samples (vegetables, water and milk) were taken from the vicinity of Baie Mare and from Poiana Botizei (mountain area). If the contamination levels were predictable for the area of Baia Mare, the dose of milk

Corresponding author: Bud Adina, Ph.D. student, University of Petrosani, Petrosani, Romania, (University of Petrosani, 20 University Street, bud.adina@yahoo.com) 16

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contamination in Poiana Botizei remains surprising. Goat, sheep and cow's milk were taken from this area. The animals graze in an isolated, mountainous area, they drink water from springs and streams (clean water), but during the summer they also drink water from Poieni and Cizma brooks, which cross the locality. This stream is heavily contaminated, as evidenced by the analyses of water and sediment. Milk samples showed alarming concentrations of heavy metals, especially lead, in excess of tens of times. These analyses demonstrate the impact of the irresponsible closure of Băiuț mining perimeter (respectively Cizma) with the destruction of the aquatic environment, food contamination and finally the contamination of the uninformed population on the risks to which it is exposed. More studies are needed, including information, but the most important thing is to find urgent technical solutions to stop the pollution. The reasonable solution involves the exploitation of the mineral resource from Cizma perimeter and the backfilling of the exploited space with minerals with a buffering role (limestone, zeolites) located in the area. The "concern" of the authorities so far has been to set up a protected area in the former mining perimeter, which, instead of solving the problems, has made the situation even more complicated. Table 1 presents the analyses of the results obtained on the water and food samples from the studied locations. For each sample, a set of analyses was performed for several metals considered to be at risk of accumulation. Only metals that could be determined within the measuring limits of the devices were shown in the table (metals below the detection limit were not shown in the table). Table 1. Values of heavy metals determined from water and food samples

No.

Food / water sampling location

U.M.

Metal

Value obtained

Maximum allowed value

mg/l

nickel manganese copper zinc lead cadmium copper zinc arsenic zinc arsenic nickel copper zinc manganese copper zinc manganese nickel manganese lead nickel manganese manganese lead manganese lead manganese lead

0,066 0,518 0,25 3,17 0,32 0,12 0,40 8,04 0,07 10,8 0,05 0,03 0,41 1,28 1,61 2,31 4,31 3,48 0,36 1,20 0,05 1,4 81 0,5 0,25 0,08 0,47 0,15 1,37

0,02 0,05 * * * * * * * * * * * * * * * * * * * 20 50 * * * * * *

Fountain near Tăuții de Sus pond

Land next to Tăuții de Sus pond (onion)

mg/kg

Land next to Tăuții de Sus pond (mixture of lettuce leaves and celery leaves)

mg/kg

Land next to Tăuții de Sus (salted goat cheese) Downstream pond Leurda - Băiuț (dried onion)

mg/kg

Downstream pond Leurda - Băiuț (garlic)

mg/kg

Downstream Central Pond - Tăuții de Sus (dried onions)

mg/kg

g/l

Downstream Central Pond - Tăuții de Sus (hay water) Poiana Botizei (goat's milk)

mg/kg

Poiana Botizei (cow's milk)

mg/kg

Poiana Botizei (sheep's milk)

mg/kg

Obs. * the values interpreted in point 2 3. Interpretations of heavy metal contents in relation to the legislation in force The values obtained were compared with the values settled by Law no. 458/2002 on drinking water quality [10]. By relating the values determined in the laboratory to the values in the law, exceeding values were obtained for manganese (10.36 times) and for nickel (3.3 times) (in the case of sample 1, determinations were made in the laboratory of Vital SA). 17

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A sample of a mixture of lettuce leaves and celery leaves (sample 3) and a goat cheese sample (sample 4) were taken from this location. In this area there is a goat farm that grazes near the pond. The cheese was preserved in brine. The determinations were performed in the ICIA laboratory - the branch of the Research Institute for Analytical Instrumentation in Cluj-Napoca. The second location is downstream the mining perimeters: downstream Leurda - Băiuț pond; downstream Central - Tăuții de Sus / Baia Mare pond and downstream Cizma mining perimeter in Poiana Botizei locality. A sample of garlic (sample 6) and a sample of dried onion (sample 5) were taken from Leurda pond downstream location. A goat's milk sample was taken from Poiana Botizei (sample 9); cow's milk sample (sample 10); sampled sheep's milk (sample 11). For the milk samples from Poiana Botizei (cow, goat and sheep) there is evidence of contamination with heavy metals, even if they are fed with grass from the mountain area, but are watered during the summer from tributaries of Poiana Botizei brook (uncontaminated) and sporadically from the Poiana Botizei brook (with Cizma tributary, heavily contaminated). In the case of cow's milk, it should be noted that the cows were given in the last 5 months (winter months) only spring water, uncontaminated water. In this way, the influence of food contamination in an emissary can be noticed even if the animals’ water drinking occurs only at certain times of the year and not permanently. From discussions with farmers, they said that some animals sometimes refuse water from the stream. The level of contamination of the stream is so strong that there are no signs of life in it. It was also found that these farmers are not informed about the risks they are exposed to by using water contaminated by animals. Regarding the risk of consuming these contaminated products, reports have been made to different legislations: Romanian, European, American, IARC (International Agency for Research on Cancer) and WHO. [13], [14]. The common principle of these legislations is given by the level of contamination accumulated over a certain period of time expressed in units of metal / kg body. In order to distinguish separately the risk posed by heavy metals, the problem is complicated by the addition of contaminants of other products related to the eating habits of those persons. For example, the literature specifies the contamination of rice with cadmium. If a person constantly consumes rice to which are added the contaminated products from the mining areas, the level of risk is easily reached. A calculation made for the situation of people who grow their salad in Tăuții de Sus (sampling area) shows that an average consumption of 1 kg of salad/week reaches a level of major risk of cancer (strictly from salad). In the case of the milk taken from Poaia Botizei in which the lead content was 1.37 mg / kg dry matter, respectively 1370 micrograms / kg, while assuming a consumption of one kg of cheese (produced from this milk) for a child of 20 kg during two weeks, it determined the accumulation in the body, strictly from this product, of 34.25 micrograms, exceeding the maximum value allowed by the WHO of 25 micrograms / kg body /week. If a consumption of 1 kg / week is reached, 68.5 micrograms / kg body weight is accumulated. These calculations are performed on the assumption that the person concerned would have no other source of exposure, including remanence. In the case of the salad mixture, at a consumption of 1 kg / week for a child of 20 kg, the value of 6 micrograms / kg of cadmium body is reached, and in two weeks, 12 micrograms / kg of body is accumulated. According to the WHO, the limit is 7 micrograms / kg body weight / week of cadmium. By reference to Commission Regulation (EU) 2015/1005 of 25th of June 2015, amending Regulation (EC) No. 1881/2006 as regards the maximum levels of lead in certain foods, in which the values for milk are 0.02 mg / kg, the exceeding value, in the case of the goat milk samples (Poiana Botizei), is 12,5 times higher, for sheep's milk 68.5 times, and for cow's milk 23.5 times. Another way of assessing the risk of lead consumption given by the WHO is 0.5 micrograms / kg body weight / day which leads to an excess of 8.56 times in the case of consumption of 250 grams of cheese by an adult with a mass of 80 kg (assuming the only source of lead contamination). These scenarios show the risks to which the population in these areas is exposed through consuming contaminated products and water. [12] By reference to Regulation (EU) no. 488/2014 of the Commission of 12th of May 2014, amending Regulation (EC) no. 1881/2006, as regards maximum cadmium levels in foodstuffs, the limit set for leafy vegetables is 0.05 milligrams / kg, which is 2.4 times the case for lettuce and celery leaves for Tăuții sample and 3.2 times lead (with a limit of 0.1 mg / kg). [12]

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4. Conclusions This paper highlights the new context of pollution in Maramureș County generated by an irresponsible action on how to close the mining perimeters. These closure activities have been described and detailed in previous works 8, which pointed out the new problem given by the magnitude of the phenomenon of release of ever-increasing quantities through another transport vector, namely mine waters through acid drainage. Mine water discharges are limited and variable (depending on the level of precipitation with relatively constant flows), to which are added discharges with uncontrollable and very high flows, called untimely discharges. If studies to date have shown high levels of heavy metals, especially in soils and restricted areas, in the future the risks to the environmental impact of heavy metals will be posed by the expansion of these areas through the transport of pollutants by contaminated rivers. Most of the studies were performed for Baia Mare and the belonging localities for which the contamination levels were shown, but the new studies must be directed on the widest possible areas and in close relation with the contaminated rivers. For example, discharges from Băiuț - Cavnic area have contaminated Cavnic and Lăpuș rivers in important parts, turning them into dead rivers. The two rivers intersect, causing contamination of Someș River. In addition to the two rivers, Săsar River and numerous other streams that drain the eastern part of Maramureș mining basin (Săsar, Nistru, Băița, Ilba perimeter) contribute to the contamination of Someș River. Another area with the same environmental impact is located in the north of the county, in Borșa mining perimeter, from which two important rivers are contaminated: Cisla and Vaser, which reach Vişeu river and later the Tisza. The intake of heavy metals in water and soil contributes to their bioaccumulation in the food chain. On the alignment of Lăpuș and Someș, the main activity of the population is agriculture and fishing, which endangers their health, including the people who buy their products. In this context, time will not lead to a decrease in pollution despite the closure of mining, on the contrary, it will lead to an increase. Due to the complexity of the mineralization in the vein area, the multitude of heavy metals leads to a synergistic effect, further amplifying the impact.

References [1] Coroian Aurelia, Miresan Vioara, Cocan Daniel, Răducu Camelia, Longodar Adina Lia, Pop Alexandra, Feher Grațian, Andronie Luisa, Marchis Zamfir, 2017 Physical-chemical parameters and the level of heavy metals in cow milk in the Baia Mare area, Banat’s Journal og Biotechnology [2] Roba Carmen Andreea, Baciu Călin, Rosu Cristina, Pistea Ioana Cristina, 2015 Heavy metals in soils from Baia Mare mining impacted area (Romania) and their bioavailability, Geophysical Research Abstracts, Volume 17 / 2015 [3] Big Cristina-Laura, Lăcătușu Radu, Floarea Damian, 2012 Heavy metals in soil-plant system around Baia Mare, Carpathian Journal of Earth and Environmental Sciences [4] Mihali Cristina, Oprea Gabriela, Michnea Angela, Jelea Stela-Gabriela, Jelea Marian, Man Călin, Șenilă Marin, Grigor Laura, 2013 Assessment oh heavy metals content and pollution level in soil and plants in Baia Mare area, NW Romania, Carpathian Journal of Earth and Environmental Sciences, Volume 8, Issue 2 / 2013 [5] Bora Florin Dumitru, Bunea Claudiu Ioan, Chira Romeo, Bunea Andreea, 2020 Assessment of the Quality of polluted Areas in Northwest Romania Based on the Content of Elements in Different Organs of Grapevine, MDPI Molecules [6] Boros Melania-Nicoleta, Smical Irina, Micle Valer, Lichtscheidl-Schultz Irene, 2015 Heavy metals pollutions of soils from Baia Mare – case study: Cuprom Industrial Area, Environmental Engineering, Volume IV / 2015 [7] Miclean Mirela, Cadar Oana, 2021 Dietary Metals (Pb, Cu, Cd, Zn) Exposure and Associated Health Risks in Baia Mare Area, Northwestern Romania, Journal of Biomedical Research [8] Bud A., 2022 Determinations and interpretations of heavy metal analysis in the sediments and water of Cavnic and Lăpuș rivers, Revista Minelor, nr. 1 / 2022

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[9] *** NTPA 001 [10] *** Law no. 458/2002 regarding the quality of drinkable water [11] *** EU Regulation no. 488 / 2014 of the E.C. from 12th May 2014, modifying the E.C. Regulation no. 188 / 2006 regarding the maximum admissible levels of Cadmium from aliments. [12] *** EU Regulation no. 1005 / 2015 of the E.C. from 25 th June 2015, modifying the E.C. Regulation no. 188 / 2006 regarding the maximum admissible levels of Lead from various aliments. [13] The National Institute of Public Health, 2020 Informative Guide regarding the new Romanian legislation [14] International Agency for Research on Cancer, World Health Organization, 2020 IARC Monographs on the evaluations of carcinogenic risks to human, Arsenic, metals, fibers, and dusts, A review of carcinogens, Volume 100 C

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RESEARCH REGARDING IRON SLUDGE RECOVERY TECHNOLOGY Eugen TRAISTĂ1*, Camelia TRAISTĂ2 1

University of Petrosani, Petrosani, Romania, eugen_traista@yahoo.com 2 University of Petrosani, Petrosani, Romania

DOI: 10.2478/minrv-2022-0010 Abstract: One of the most important wastes in iron metallurgy is the blast furnace sludge. This sludge consists of fine particles of iron ore, coke and fine particles of flux. The furnace sludge is characterized by the chemical composition similar to that of the furnace load, the major difference being the concentration of zinc and lead. Due to the similarity with the blast furnace load, this material, after pelletization, can be recycled in the technological process. However, this recirculation is limited by the zinc content, which significantly disrupts the operation of the furnace. This paper presents tests to reduce the zinc content of the furnace sludge by hydrometallurgical and pyrometalurgical processes. Keywords: iron sludge, metallurgy, iron ore, recovery, furnace, leaching 1. Introduction As a result of industrial development, more and more industrial waste results during production processes. From the iron production processes results the furnace sludge which is one of the hazardous metallurgical wastes [1]. The production of iron and its alloys is the most important metallurgical process [2]. In the production process, in addition to Fe and C, many other elements are introduced into the furnace. Zinc is especially a problem because during the metallurgical process it distills due to the very high temperatures in the furnace and subsequently condenses on the furnace walls in areas with lower temperature, which leads to a large amount of dust and possible damage to the furnace. For a good process, the Zn concentration in the ore must not exceed 0.12 kg per tonne of cast iron produced. Partly, the evaporated zinc condenses on the dust particles in the effluent gas, the higher concentration of zinc founding in the finer dust particles. Normally each ton of cast iron results in 8 - 12 kg of dust. This dust is removed by the flue gas purification system. Large particles are removed from the gases by cyclones and filter bag filters and can be reintroduced directly into the furnace after sintering because the Zn content is generally low (<0.1% Zn). Fine particles are removed through a wet scrubber from which results a sludge [2]. Generally, blast furnace sludge contains 21-32% Fe, 15-35% C, 1.0-3.2% Zn and 0.3-1.2% Pb, reported to dry mass [3, 4]. In Europe alone, the steel industry produces about 500,000 tons of blast furnace sludge annually. Because the iron and coke content of the sludge is high, it is possible to recycle the sludge in the furnace. However, due to the zinc content of a few percent, the use of this sludge is restricted. The resulting sludge after removal of fine dust in wet filters is deposited in a tailings pond. Groundwater can contaminate groundwater with zinc and lead in this sludge. Also, the new regulations no longer allow long-term storage of waste. For this reason, research is being done for the recovery of these sludges, including by pyrometalurgical processes [3, 5]. 2. Test on Romanian iron sludge For these tests were taken into account the furnace sludge from the former steel plant Sidex Galați, stored in the ponds from Mălina. In order to compare Mălina sludge with the other, 29 samples were taken from all

Corresponding author Eugen Traistă, Assoc prof. Ph.D / University of Petrosani, Petrosani, Romania (University of Petrosani, 20 University Street, eugen_traista@yahoo.com) *

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surface of settling ponds. The average elemental contents and the range of elemental concentration variation are presented in table 1. Table 1. The average elemental contents of Mălina sludge

Range

Element

Content [%]

Minimal

Maximal

MgO Al2O3 SiO2 P 2O 5 SO3 Cl K2O CaO TiO2 V2O5 Cr2O3 MnO Fe2O3 Co2O3 NiO CuO ZnO PbO

0,2840 0,1868 0,9391 0,0934 0,4656 0,1428 0,0636 16,3724 0,0420 0,0132 0,0673 1,2370 65,9528 0,0047 0,0237 0,0269 0,6798 0,1153

0,0720 0,0983 0,5150 0,0592 0,2309 0,0461 0,0311 7,3885 0,0000 0,0000 0,0000 0,8547 45,8834 0,0000 0,0000 0,0000 0,2899 0,0000

1,1009 0,3976 1,6967 0,1452 1,8719 0,2561 0,1198 25,6999 0,2001 0,0632 0,2547 1,6091 86,1069 0,0768 0,1667 0,0740 1,5912 0,3038

LOI

13,0700

0,1652

26,3282

This results indicate that entire amount of sludge can be valuated, if the material is correctly managed. This involve to mix pour iron content sludge with rich iron content iron. The known iron content commercial limitation is over 62% Fe2O3. A number of 12 samples (41%) not join with this target. Zinc content mast be less than 0,5% (ZnO < 0,373). Just 3 samples (10%) are under this limit. If 40% of zinc is removed, 50% of sludge may be used in furnace. In order to reduce the zinc content, preliminary leaching tests are made. Table 2. Preliminary leaching tests

Elements

Original

1M H2SO4 leaching

CO2 leaching

40% NaOH leaching

MgO Al2O3 SiO2 P 2O 5 SO3 Cl K2O CaO TiO2 V2O5 Cr2O3 MnO Fe2O3 Co2O3 NiO CuO ZnO PbO

0,0720 0,1206 0,6253 0,0988 0,2653 0,1791 0,0570 14,9346 0,0000 0,0000 0,0540 1,4683 67,4150 0,0000 0,0000 0,0246 1,5912 0,0593

0,0000 0,1449 0,6321 0,0531 0,0977 0,0071 0,0554 1,0343 0,0698 0,0000 0,0908 1,6988 95,2998 0,0000 0,0000 0,0000 0,6936 0,1353

0,1514 0,1431 0,8274 0,1059 0,1381 0,0160 0,0397 15,5055 0,0000 0,0000 0,0536 1,1889 66,6970 0,0000 0,0000 0,0235 1,0825 0,2476

0,2760 0,3916 1,3402 0,0728 0,5524 0,0164 0,1159 17,4388 0,0000 0,0000 0,0664 1,3188 63,8999 0,0000 0,0370 0,4124 1,5555 0,5499

12,7416

0,0000

13,5117

11,8073

56,41

31,97

2,24

Zn removal [%]

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This results are similar with that indicated in different authors references. The relatively poor results are due to the way zinc is chemically bound in the dust particles. Zinc is mainly present in the form of ZnFe2O4 (franklinite) and less in the form of zinc oxide ZnO (zincite). Iron, with the exception of franklinite, is in the form of magnetite, Fe3O4 and hematite, Fe2O3. Zinc oxide can be easily recovered by acidic or alkaline leaching, unlike franklinite which is refractory to these processes. Although alkaline leaching has the advantage of a small iron extraction, the leaching medium is relatively concentrated [6]. In contrast, the use of acids does not require such a high concentration as in the case of alkaline leaching, but iron is dissolved in the solution in this case. After purification of the solution resulting from leaching, the dissolved metals can be recovered by various methods, such as precipitation, crystallization, solvent extraction, ion exchange, electrolysis, etc. In the leaching process, the selective solubility of zinc relative to that of iron is critical. Several authors (Marcos Vinícius Cantarino, Celso de Carvalho Filho and Marcelo Borges Mansur) have found an increase in the efficiency of zinc removal by heating sludge. 3. Zinc leaching methods 3.1. Acid leaching Through the leaching process, the research aims to identify such conditions of hydrometallurgical treatment so that the zinc is dissolved in the solution while the iron remains in the residue. Zinc is recovered from the solution, while solid residues can be recycled in the iron manufacturing process. The table below compares the leaching efficiency of zinc and iron in blast furnace sludge in the case of the use of different acids. Table 3. Leaching efficiency of zinc and iron by using different acids

Leaching agent

L/S ratio

Zn extracted [%]

Fe extracted [%]

20 20 20

78.71 67.66 69.84

2.97 2.05 2.96

1 M H2SO4 1 M HNO3 1 M HCl

The comparison between the use of different acids showed that sulphuric acid is an ideal leaching agent for separating zinc from blast furnace sludge. The leaching process with sulphuric acid has the advantage that zinc is extracted selectively in relation to iron at a lower cost. Our test results on Mălina sludge using 1 M H2SO4 are shown in table 4. Table 4. Leaching tests using 1 M H2SO4

Component MgO Al2O3 SiO2 P 2O 5 SO3 Cl K2O CaO TiO2 V2O5 Cr2O3 MnO Fe2O3 Co2O3 NiO CuO ZnO PbO Zn removal

P12

Acid leaching

Acid leaching of 400C preheated material

0,0720 0,1206 0,6253 0,0988 0,2653 0,1791 0,0570 14,9346 0,0000 0,0000 0,0540 1,4683 67,4150 0,0000 0,0000 0,0246 1,5912 12,7416

0,0000 0,1449 0,6321 0,0531 0,0977 0,0071 0,0554 1,0343 0,0698 0,0000 0,0908 1,6988 95,2998 0,0000 0,0000 0,0000 0,6936 0,0000

0,5243 0,5319 2,5284 0,0494 0,1710 0,0195 0,0580 13,0213 0,0938 0,0000 0,2512 2,0132 79,2751 0,0000 0,0451 0,0371 1,1412 0,0000

56,41

39,43

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Our test shown that is better to use, in acid leaching, original material. 3.2. Alcaline leaching Alkaline leaching consists of treating the furnace dust with a caustic soda solution, followed by recovery of the zinc by electrolysis simultaneously with the regeneration of the alkaline solution for reuse. The major advantage of alkaline leaching is the selectivity of zinc extraction compared to iron. Selective extraction of zinc compared to iron is demonstrated with the equilibrium diagrams, which indicate how the dissolution of iron hydroxide and zinc oxides are pH dependent. These diagrams indicate that zinc is soluble in both acidic and alkaline media, while iron is soluble in acidic media.

Figure 2. Ferrous hydroxides solubility of as a function of pH, at 25 °C

Figure 1. ZnO Solubility as a function of pH, at 25 °C

Figure 3. Ferric hydroxides solubility of as a function of pH, at 25 °C

Alkaline leaching is considered effective in dissolving heavy metals, compared to iron. Caustic soda efficiently dissolves the oxides of Zn, Pb and Al and, in limited cases, Cr and Cu. The solubility of certain amphoteric elements in alkaline solution decreases in the following sequence Zn> Pb> Al> Cr (III)> Cu. The solubility of Cr (III), Cu and Cd is negligible in the presence of zinc and lead. Also, the solubility of lead decreases with increasing zinc content. The main dissolution reactions in caustic soda are: ZnO + 2NaOH = Na2ZnO2 + H2O (1) PbO + 2NaOH = Na2PbO2 + H2O (2) Instead, zinc ferrite is a very stable compound and only partially dissolves in alkaline solutions. Alkaline solutions also dissolve aluminum oxide and silica, but their solubility is limited in the case of iron dust. SiO2 + 2NaOH = Na2SiO3 + H2O (3) Al(OH)3 + NaOH = Al(OH)4- + Na+ (4) After leaching with NaOH, is obtained a residue enriched in iron and depleted in zinc and lead which corresponds to the requirements for recycling. Test made in laboratory on Mălina iron sludge using 40% NaOh solution show the results in table 5. 24

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Table 5. Leaching tests using 40% NaOH

Compound

Original

Orininal NaOH leaching 400C calcinated NaOH leaching

MgO Al2O3 SiO2 P2O5 SO3 Cl K 2O CaO TiO2 V 2O 5 Cr2O3 MnO Fe2O3 Co2O3 NiO CuO ZnO PbO

0,0720 0,1206 0,6253 0,0988 0,2653 0,1791 0,0570 14,9346 0,0000 0,0000 0,0540 1,4683 67,4150 0,0000 0,0000 0,0246 1,5912 0,0593

0,2760 0,3916 1,3402 0,0728 0,5524 0,0164 0,1159 17,4388 0,0000 0,0000 0,0664 1,3188 63,8999 0,0000 0,0370 0,4124 1,5555 0,5499

0,2282 1,9908 9,8479 0,1568 1,1586 0,0574 0,4562 14,9460 0,2150 0,0000 0,1541 2,0659 66,8682 0,0000 0,0000 0,0510 0,9420 0,0000

12,7416

11,8073

0,3331

2,24

40,80

Zn removal

3.3. Carbon dioxide solution leaching The solubility of zinc in carbon dioxide solutions depends on the temperature, ionic strength, pH and partial pressure of carbon dioxide. The following reactions occur in an acidic medium: ZnCO3 (s) = Zn2+ (aq) + CO32- (aq) (5) H+ (aq) + CO32- (aq) = HCO3- (aq) (6) H+ (aq) + HCO3- (aq) = H2O + CO2 (aq) (7) CO2 (aq) = CO2 (g) (8) ZnCO3 (s) + 2H+ (aq) = Zn2+ (aq) + H2O + CO2(g) (9) And in the aqueous carbon dioxide acidic solution: ZnCO3 (s) = Zn2+ (aq) + CO2 (10) H+ (aq) + CO32- (aq) = HCO3- (aq) (11) CO2 (aq) = CO2 (g) (12) + CO2 (aq) + H2O = HCO3 (aq) + H (aq) (13) ZnCO3 (s) + CO2 (g) + H2O = Zn2+ (aq) + 2HCO3- (aq) (14) The solubility of zinc increases as the partial pressure of carbon dioxide increases and the main species in the solution at a high partial pressure of carbon dioxide is HCO3-. The solubility values of zinc carbonate in water taken from the literature are in table 6. Table 6. The solubility of zinc carbonate in water

Temperature [K]

PCO2/bar (CCO2/mol L-1) or pH

288.15

0.987 0.00032 0.00032"

291.15

1.56

298.1

298.15

Zinc Carbonate Solubility ZnCO3/mol L-1 1.98 x 10-3 1.64 x 10-4 8 x 10-5 5.6 x 10-5 6.7 x 10-3 1.98 x 10-3

Reference

von Essen 1897 Haehnel 1924 Haehnel 1924 Kelley, Anderson 1935

In order to check this theory, CO2 leaching test are made, with results presented in table 7.

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

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Compound MgO Al2O3 SiO2 P 2O 5 SO3 Cl K2O CaO TiO2 V2O5 Cr2O3 MnO Fe2O3 Co2O3 NiO CuO ZnO PbO PC

Original material

Original material CO2 leacheate

400 calcinated material CO2 leacheate

0,0720 0,1206 0,6253 0,0988 0,2653 0,1791 0,0570 14,9346 0,0000 0,0000 0,0540 1,4683 67,4150 0,0000 0,0000 0,0246 1,5912 0,1353 12,7416

0,1514 0,1431 0,8274 0,1059 0,1381 0,0160 0,0397 15,5055 0,0000 0,0000 0,0536 1,1889 66,6970 0,0000 0,0000 0,0235 1,0825 0,2476 13,5117

0,339 1,0781 0,0000 0,0447 0,0794 0,0322 0,092 18,7498 0,1837 0,0000 0,1018 1,2609 76,0652 0,0000 0,0000 0,0278 0,6619 0,0000 0,3331

31,97

58,40

Zn removal

This results are satisfactory, but the technology requires large amounts of water because of zinc dicarbonate low solubility. 4. Pyrometalurgical method Zinc is found in sinter in the form of oxides (ZnO), ferrite (ZnO·Fe2O3), silicates (2ZnO·SiO2) and sulfide (ZnS). Zinc reduction, vaporization, condensation, oxidation and circulation take place in the furnace. At temperatures higher than melting points (690 K) and boiling points (1190 K) zinc oxide is easily reduced in the furnace. In the vapor phase between 1190 and 1273 K, zinc sublimates and moves to the upper areas of the furnace. ZnO(s) + [C] = Zn(g) + CO(g) (15) Volatilized zinc gas, in contact with water vapor and carbon dioxide, oxidizes and deposits in the upper part of the furnace forming dense crusts. Zn(g) + H2O(CO2) = ZnO + H2(CO) (16) These formations adversely affect the furnace operations. Zinc is volatilized in the temperature zone of 1173-1373 K which results in a decrease in the temperature of the zone. For this reason, 11 kg of coke is consumed for every kilogram of volatilized zinc. In order to do this, the original dried material was pelletized and introduced in a melting oven. Table 8. Pre-reduced sludge composition

Compound MgO Al2O3 SiO2 P 2O 5 SO3 Cl K2O CaO TiO2 V2O5 Cr2O3 MnO

Sample I

Pre-reduced sample I

Sample II

Pre-reduced sample I

0,1277 0,1316 0,5977 0,1043 0,2940 0,2130 0,0511 18,1580 0,0000 0,0000 0,0665 1,6091

0,2831 0,7977 4,5856 0,1643 0,7103 0,1073 0,2231 17,6125 0,0781 0,0178 0,1047 1,6487

0,1382 0,1042 0,6936 0,0783 0,3474 0,2041 0,0619 17,7578 0,0000 0,0494 0,0477 1,1312

0,1952 1,5964 7,9446 0,1545 1,0191 0,0662 0,3818 15,6204 0,1881 0,0000 0,1426 1,9561

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590 Fe2O3 Co2O3 NiO CuO ZnO PbO

60,2396 0,0000 0,0000 0,0314 0,8650 0,2437

17,1309

vol. 28, issue 2 / 2022 pp. 21-28 71,6684 0,0000 0,0482 0,0238 1,4813 0,1617

59,9655 0,0000 0,0385 0,0280 0,8693 0,2754

68,6779 0,0000 0,0252 0,0534 1,0806 0,3661

17,9969

An increasing of zinc content may be observed because of coke and carbonates removing during melting process. Vitrifyed and pre-reduced sludge may be easily crushed, but not milling. We try to mill this product with the hope that zinc oxide cumulated in nonmagnetic fraction. Results obtaining for magnetic separation of crushed melted material are: Table 9. Pre-reduced sludge magnetic separation tests

Compound MgO Al2O3 SiO2 P 2O 5 SO3 Cl K2O CaO TiO2 V2O5 Cr2O3 MnO Fe2O3 Co2O3 NiO CuO ZnO PbO

Fe sample I magnetic

Fe sample I nonmagnetic

Fe sample II magnetic

Fe sample II nonmagnetic

0,3175 0,9142 4,6804 0,1591 0,6645 0,1075 0,1929 17,4584 0,1064 0,0000 0,0949 1,5834 71,3850 0,0000 0,0603 0,0000 1,7737 0,3154

0,2602 0,7201 4,5224 0,1678 0,7409 0,1072 0,2433 17,7152 0,0593 0,0296 0,1112 1,6923 71,8573 0,0000 0,0401 0,0397 1,2863 0,0593

0,1458 1,0048 5,0896 0,1510 0,8098 0,0795 0,2702 16,6320 0,1478 0,0000 0,1254 1,7913 71,3925 0,0000 0,0629 0,0571 1,2886 0,4155

0,2282 1,9908 9,8479 0,1568 1,1586 0,0574 0,4562 14,9460 0,2150 0,0000 0,1541 2,0659 66,8682 0,0000 0,0000 0,0510 0,9420 0,3331

This material preserved initial zinc content, but it contains 7% of reduced iron and may be used, in mixture with scrap in electric furnace for steel production. We test this material for this purpose and melt it at 1600C when pig iron were obtained: Table 10. Pig iron production test result

Compound Al2O3 SiO2 SO3 Cl K2O CaO TiO2 Cr2O3 MnO Fe CuO PbO

Pig iron 0,4188 1,2885 0,1609 0,0655 0,1385 0,7717 0,0627 0,0729 0,8156 95,5262 0,0992 0,0912

We also obtain a sludge with high content of reduced iron because of high viscosity of melted sludge at 1600C. After crushing, magnetic fraction was separated: 27

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Table 11. Pig iron sludge magnetic separation test

Compound MgO Al2O3 SiO2 P2O5 SO3 Cl K 2O CaO TiO2 V 2O 5 Cr2O3 MnO Fe2O3 Fe Co2O3 NiO CuO ZnO PbO

Magnetic sludge

Nonmagnetic sludge

0,4895 1,5973 9,0730 0,4057 0,8642 0,0716 0,1108 37,8125 0,5704 0,1293 0,0679 3,6353 11,5785 34,7135 0,0000 0,0000 0,0000 0,2813 0,0578

0,4279 2,5501 13,6901 0,4928 0,9770 0,1250 0,5724 54,7018 0,8354 0,1723 0,0000 5,5383 17,8132 0,0000 0,0000 0,0494 0,9260 0,3225

Magnetic fraction may be improved by advanced crushing. This option, that allow to obtain pig iron seems to be the most suitable for the sludge with high zinc content. 5. Conclusions Leaching tests on original material extract weakly zinc because of it linking by iron oxide as franklinite. By heating at 400 degrees the zinc solubility increase. Acid leaching using sulphuric acid is the best leaching method, but this technology is certainly not environmental friendly. Sodium hydroxide leaching is the best hydrometalurgical method that may be used, but required large amounts of fresh water to wash sludge after zinc removal in order to reduce sodium content. Pig iron obtaining is, in our opinion, the best method for iron sludge valuation. References [1] Mansfeldt T., Dohrmann R., 2020 Chemical and mineralogical characterization of blast-furnace sludge from an abandoned landfill Environmental science & technology, November 15, 2004, Volume 38, Issue 22, Pages 430A-6176 [2] van Herck P., Vandecasteele C., Swennen R., Mortier R., 2000 Zinc and Lead Removal from Blast Furnace Sludge with a Hydrometallurgical Process, September 1, 2000, Volume 34, Issue 17, Pages 361A-3830 [3] Das B., Prakash S., Reddy P.S.R., Misra V.N., 2007 An overview of utilization of slag and sludge from steel industries, Resources, Conservation and Recycling, Volume 50, Issue 1, March 2007, Pages 40-57 [4] Dvořák P., Jandová J., 2005 Hydrometallurgical recovery of zinc from hot dip galvanizing ash, Hydrometallurgy, Volume 77, Issues 1–2, April 2005, Pages 29-33 [5] Asadi Zeydabadia B., Mowlaa D., Shariatb M.H., Fathi Kalajahia J., 1997 Zinc recovery from blast furnace flue dust, Hydrometallurgy, Volume 47, Issue 1, November 1997, Pages 113-125 [6] Vereš J., Jakabský S., Lovás M., 2011 Zinc recovery from iron and steel making wastes by conventional and microwave assisted leaching, Acta Montanistica Slovaca Ročník 16 (2011), číslo 3, 185-191 This article is an open access article distributed under the Creative Commons BY SA 4.0 license. Authors retain all copyrights and agree to the terms of the above-mentioned CC BY SA 4.0 license. 28

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NEW CHALLENGES TO THE DEEP DEVELOPMENT OF THE BULQIZA CHROME MINES Edmond GOSKOLLI 1* 1

National Agency of Natural Resources (NANR-AKBN), Tirana Albania, egoskolli@gmail.com

DOI: 10.2478/minrv-2022-0011 Abstract: Bulqiza chrome mine is one of the most important chromium mines and mining activities in Albania. It is the deepest mine in the Balkans and possibly even in Europe. Recently, the inner shaft of the mine reached a depth of 1000 m, measured from the surface, or -180 m below sea level. Like all deep metal mines, this mine also faces a different set of challenges during its development. The first and most important challenge is that of improving the degree of geological research and knowledge of this mine and assessment of geological resources and reserves according to JORC Code 2012 edition. In addition, a series of other challenges related to increasing the depth of the mine represent the object of this paper: rock and ore stability and the underground voids support; improvement of mining methods and technologies; groundwater and its pumping; temperature, air parameters and mine ventilation. Among other things, these problems were solved using various computation and simulation programs. Keywords: chromium mine, inner shaft, rock and ore stability, mining method, mine ventilation, VENTSIM 1. General considerations Bulqiza deposit itself is the most important chromium deposit in Albania and unique in its kind. The documented beginning of chromium production in Bulqize show that mine started in 1948, and from that year on it continuously increased to reach the highest value in 1986 of 467,000 tons; meanwhile the ore production from Bulqiza North mine has been 270 000 tons/year [1]. By the end of the previous year, Bulqize produced 14.74 million tons. The amount of mineral resources/reserves and the realized production show that the Bulqize deposit is the most important source of chrome ore in Albania. The exploitation of this source has been done with underground way by experimenting different mining methods and using, definitively, the sub-level stopping mining method. Until 2001, the Chromium Mining Bulqizë had the status of a state-owned enterprise, while it is currently part of the concession agreement of the company "ALBCHROME sh.p.k. The chromium ore production trend of this mine was almost the same as that of the country, representing more than 50% of it. A series of mining capital works have been constructed for the ore exploitation of Bulqiza North Mine, from its beginning until 2014, such as:  About 2,100 m vertical shafts with diameter 4.-4.5 m;  More than 1,120 m of declines with a cross-section over 7.2 m2;  About 35 km of horizontal works for the preparation and use of minerals in the levels;  A large number of vertical mine workings for ventilation and escape way;  Significant constructions and installations for the provision of infrastructure and power, compressed air and water supply. (see Figure 1) Currently, this mine, like other mines and chromium ore processing units as well as two ferrochrome smelters belong to the local concessionary company "ALBCHROME" Ltd, which is part of BALFIN Group

Corresponding author: Edmond Goskolli, Assoc. Prof. PhD. Nation Agency of Natural Resources (NANR-AKBN), Tirana Albania, egoskolli@gmail.com, e.goskolli@akbn.gov.al 29

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Bater -Bulqiza Bord

Lev V

Lev XIV

Lev XXI

Figure 1. Bulqiza mine vertical section with main mine workings

2. Geological challenge and estimation of chromium mineral resources / reserves The Bulqiza deposit itself, from a geological point of view, including the ore body shape, the tectonics, the fracturing system, the extension, the deep angle, and further developmentURIMI in itsZË kind. For this BULQI VENDB is unique reason it has been paid special attention by local and foreign researchers and designers. PRERJA TËRTHORE III - III The geological works carried out years ago could 100 200 m 0 Az. 80° provide data regarding the geological construction of Q the deposit, its structure and texture of the ore body, H P 1 the tectonics and the estimation of the ore reserves [2]. H Q L1 D D On the market economy, the banks, the mining LII-1 H PIV companies and the shareholders involved in the H mining industry provide investment and support the H development of the mining industry by conducting exploration, exploitation and processing of ore D resources. Under these conditions, the concession H company and the operators are engaged to carry out H geological works in order to ensure the obtaining of LII-3 the necessary information, which will enable the assessment of resources / reserves by any international classifications [3]. H The abundant information obtained from the H numerous geological drilling carried out in the H underground can be analyzed simultaneously in order to [4]: LII-5  Make clear the value of mineral resources based H on certain classifications including parameters such as: tonnage, average content, statistic, and H geo-statistic parameters as well as technological and economic aspects; 900

650

400

150

SHPJEGUES Figure 2. Vertical cross-section of Bulqiza deposit Q

Kuaternari

Tektonikë

Dunite

Trup xeheror kromitik i pasur

Harcburgite

30 L.1

Lindor i parë

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

Collect enough data to evaluate the current mining method and to see the possibility of using another mining method;  Collect multiple data to make the assessment by means of the geotechnical classification of rock massifs and ore body and to judge about the types of support that can be used in the deep of the mine;  Obtain samples of methane, hydrogen and other gases that are present in the mines. Carrying out more 25,000 ml of a 76 mm diameter geological drilling, other geological works as galleries, traverses, raises, numerous geological documentation, measuring the zenithal and azimuthal deviation of drilling wells, sampling and performing various chemical analyzes made it possible to comply with the strict rules of JORC Code 2012 and CIM 2000. The main data about the average thickness of 2.6-3 m, the average content of Cr2O3 of 42.31 %., the deep angle of 60-75o, the total ore body length on each level of 800 m, the intensity of the tectonics and the other elements also are used in DATAMINE program to geometrize the ore body in 3D. Finally, taking into account all the results obtained from previously made geological works and those of recent years, application experts JORC Code 2012 and CIM 2000 conclude that the amount of reserves represents 2.12 million tons of mineral Chromium below the 17th level, classified accordingly:  JORC Cod 2012: 50% of reserves measured, 20% indicated and 30% inferred;  CIM (2000): 70% of reserves proved and 20% probable. Appropriate evaluation of chromium ore reserves provided security investors with the ability to study, project and continue investment in mining depth up to the absolute quota of -250 below sea level. In the mining perspective, the team in charge of drafting the depth project should solve the problems of the mining method, the support that can applied to different mine workings according to the kind of rocks in which they will be constructed, the mechanization of the works and the security problems related to the presence of different gases in the mines and mine ventilation. 3. Mining Method The mining method that is still used in the mines is the sub level stopping. This mining method has shown superiority compared to other mining methods experimented in this mine and is likely to continue to be used. Of course, in the case of an important ore body thickness, it needs a lot of improvements and mechanisms to maintain proper performance and to use machinery with compressed air (see Figures 3 and 4). This mining method is also favored by the stability of the rocks of the body hanging part, which are often composed by rocks with a RMR greater than 70, while the mineral body displays an RMR lower than 50. These geotechnical classification values also favor the use of the shrinkage mining method, which is expected to be experimented soon.

Figure 3. Pneumatic Mucking Machine LHD

Figure 4. Mini scoop with bucket capacity of 0.5m3 type ARAMINE

4. The geotechnical classification of rock massifs and ore body and types of support to be used As noted above, geological works carried out years ago, those carried out in recent years as well as the experience accumulated by the mining works carried out during these 40 years of mining activity in this mine enabled the gathering of new data, while applying the geotechnical classification of different types of rocks and body [5]. 31

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The RMR classification is applicable in the case when the rock mass along a drift is divided into a number of structural regions, i.e. zones in which certain geological features are more or less uniform [5]. The following six parameters are used to classify a rock mass using the RMR system:  Uniaxial compressive rock strength;  Rock Quality Designation (RQD);  Discontinuities spacing;  Discontinuities condition;  Groundwater conditions;  Discontinuities orientation. The six above parameters for each kind of rock are determined by field measurements. Once the classification parameters are determined, the ratings are assigned to each parameter. In this respect, the typical, rather than the worst conditions, are evaluated for a considerable number of cases with the aim to take into consideration all rock types. After the evaluations carried out, the average value of Rock Masses Rating results, while the main mining works for mine preparation are as follows:  In the 1st class, “Very good rock”, with an average value of RMR 83, about 15% of the rocks are included and are represented by pyroxenes;  In the 2nd class, “Good rock”, with an average value of RMR 65, about 60% of the rocks are included and are represented by periodontitis;  In the 3rd class, “Fair rock”, with an average value of RMR 49, about 12% of the rocks are included and are represented by dunites;  In the 4th class, “Poor rock”, with an average value of RMR 36, about 13% of the rocks are included and are represented by breccia tectonic zone and ore body. Figure 5, Bieniawski diagram, displays a considerable rock estimation. According to the respective classes, considering the roof span and the service time of the mine works, the appropriate support has been proposed and applied (see figures 6 and 7). Mine ventilation is a very important challenge because it must be able to withstand a number of important problems related to the deep development of the mines. First, it is important to take into consideration that the ranges of temperature and pressure caused by deepness variations and heat transfers produce changes in the air density that exceed 5 % and analyses that ignore these changes will produce consistent errors that impact significantly on the accuracy of planned ventilation system parameters.

. Figure 5. RMR classification of rock masses applied for Bulqiza Mine [5]

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Figure 6. Applying of rock support to the 4th class

Figure 7. Applying of rock support to the 2nd class

5. Mine ventilation In practical terms, this means that for underground facilities developing in depths higher than 500 m from the surface, the methods of analysis that ignore the compressibility of air may be incapable of producing results that lie within accurate observational tolerances [6]. Different studies conducted in mines related to microclimates and various psychometric conditions have revealed significant changes in the physical parameters of the air and working conditions in mines [7]. As the mining depth increases, barometric pressure is expected to grow, almost linearly, and its value at 1200 m depth is expected to be about 16% higher than that on the mining surface. The temperature in the dry bulb is also expected to be 30.12oC, that of the wet bulb of 21.4o C and air density 1.32 kg / m3 (about 20% higher). Numerous studies and monitoring in mines have shown that, in addition to the factors mentioned above, the further intensification of hydrogen and other gases is also an important problem. In this regard, a series of analyzes and hypotheses have been asserted about their origins. Different geochemical interpretations have contributed to the determination of its origin as a product during the process of serpentinization or further oxidation of the fayalite into the tectonic process [3]. All of these factors were used in the application VENTSIM and KLIMSIM software for air quantity determination of 132 kg/sec and dimensioning of the main works which serve as entry air way mainly of inner downcast shaft no. 9.

Figure 8. Inner shaft no. 9 cross section

Figure 9. Burning of gases at shaft no. 9 forehead

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6. Conclusions The development of the mine at a profound depth faces a number of important problems, which cannot be dealt upon in detail in this paper. Inner shaft no. 9 is going deeper and together with it various mining works are being carried out at different levels. Completing them will enable more detailed studies to be carried out regarding the problems addressed in this paper. As Bulqiza Mine is going deeper and deeper the problems related to gases released in the mines and the determination of their various quantitative and qualitative parameters conditioning the air quantity necessary for the mine ventilation should be paid a particular attention as well; Gas retention is also an important problem to be studied for the Bulqiza mine future. Geochemical studies and isotopic analyses about the different gas origins are also very important.

References [1] Bakallbashi J., Goskolli E. e.a., 2015 Feasibility study of development in depth of Bulqiza north mine, Tirana [2] Qorlaze S., Gjoni V., 1988 Geological report on Bulqiza North Chromium Deposit 1984-1988, Tirana [3] Guda V, Goskolli E. e.a., 2001 Study of gas release in chromium mine of Albania, Tirana. [4] Nesimi R. e.a., 2014 Report of the results of geological drilling conducted in the mining of northern Bulqize Bulqiza [5] Bieniawski, Z.T., 1989 Engineering rock mass classifications. New York, Wiley [6] McPherson M.J., 1988 An analysis of the resistance and airflow characteristics of mine shafts, 4th International Mine Ventilation Congress, Brisbane, Australia. [7] Goskolli E. e.a., 1990 Microclimates and working conditions in the North Bulqize mine 1987-1990.

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Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590 vol. 28, issue 2 / 2022, pp. 35-41

MINERAL WASTE, RECYCLING AND REHABILITATION OF THEIR DISPOSAL AREAS Jorgaq THANAS 1*, Aida BODE 2, Sokol MATI 3 1

Department of Mineral Resources Engineering; Faculty of Mining Geology; Polytechnic University Tirana, Albania, jorgo.thanas@yahoo.com 2 Department of Mineral Resources Engineering; Faculty of Mining Geology; Polytechnic University Tirana, Albania, bodeaida@gmail.com 3 BERALB SHA, Albania, sokol.mati@neskometal.com.tr

DOI: 10.2478/minrv-2022-0012 Abstract: This article gives an overview of solid waste and tailing generated by the mining activity over the years in Albania. It presents the geographical distribution of the disposal areas giving a quantitative and qualitative assessment of this waste. It reveals that the best approach to deal with mining waste is their recycling to recover lost mineral products deposited in the mining waste and tailing dam. This loss is due to the type of technology used over the years in mines and to the low efficiency of the processing equipment; nonetheless, the new treatment methods can represent a great potential for the recycling industries in the mining activity. At the same time the rehabilitation of the disposal areas is of great importance. Keywords: recycling, rehabilitation, inert waste, processing waste, mineral waste, sterile 1. Introduction The mining industry, due to the opening processes (main mining workings), ore body preparation workings, exploitation of mining objects, as well as the treatment of minerals in processing plants has created, over the years, large quantities of mining waste and tailings, distributed all around Albania in all mining objects and processing plants. Wastes for the mining sector in Albania are estimated at over 45 million tons and are geographically distributed almost throughout the country (12 million m3 of chromium ores, 10 million tons or 6.5 million m3 of copper ores, 4 million tons of nickel iron waste, 10 million tons of coal waste, over ten million tons of construction mineral waste, etc.) (Figure 1) [1]. Mining wasted generated over the years

5% 2%

Mining industry

11%

Copper enrichment

13%

Chromium enrichment Iron-nickel enrichment

69%

Metallurgical industry

Figure 1. Mining waste generated over the years

Corresponding author: Jorgaq Thanas, Ph.D / Department of Mineral Resources Engineering; Faculty of Mining Geology; Polytechnic University Tirana, Albania. (Rruga e Elbasanit – Tirana, Albania, jorgo.thanas@yahoo.com) 35

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During the mining process, mainly during the opening of the mining object during realisation of capital 2. Disposal areas of mining waste mining working and preparation of mineral blocks for exploitation, a large amount of solid mineral waste is created are generally at the outlets of theofcapital miningobject workings (Figure 1) (ITNPM Duringwhich the mining process,deposited mainly during the opening the mining during the carrying out of Working Group. 2006) [2], and according to the type of mineral they are classified inerte or with capital mining working and preparation of mineral blocks for exploitation, a large amount of solid mineral waste is created,impact which (Bode is generally deposited environmental A. 2010) [6]. at the outlets of the capital mining workings (Figure 2a, 2b) [2], and according to the type of mineral they are classified as inert or with environmental impact [3].

Bulqizë Bulqizë Mining chromium ore waste Mining chromium ore waste

Batër Batër Mining chromium ore waste Mining chromium ore waste

Mining waste in Bulqiza mine

Bulqizë Munellë Mining chromium ore waste as remains from opening or Mining copper ore waste as remains from opening or Bulqizë Munellë preparation of mining workings preparation of mining workings Mining chromium ore waste as remains from opening Mining copper ore waste as remains from opening or or preparation of mining workings preparation of mining workings Figure 2a. Mining waste disposal sites Figura 1. Mining waste disposal sites

During the treatment processes of different minerals (pre-treatment, beneficiation using gravity methods or flotation) big quantities of tailing are also created, which, depending on the process used, are classified as having great or small impact pollution on the environment. Tailing are distributed near the processing plants for treatment of copper, chromium, coal or iron nickel ores, which are almost all around Albania. Most of the dams now are under observation but there are many which have created problems, as far as pollution is concerned, as they are near cities, occupying big surface areas, and displaying safety problems, etc. 3. Recycling of mining waste Mining wastes deposited close to the mining objects in these two decades, especially chromium waste ore, have been subject not only to the formerly selection process of chromium ore waste by licensed entities, but also to an informal use of them, a process that has been observed to provide quantities of high grade ore that has mixed with mineral waste during the years. This phenomenon was widespread in the Batër-Bulqiza massif where safety and health problems occurred as well as the phenomenon of younger age work (Figure 3) (AKBN 2014). [4].

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Bulqizë Tailing dam

Bulqizë Chromium processing plant

Fushë Arrës Tailing dam

Fushë Arrës Copper processing plant Figure 2b. Tailing disposal sites

Figure 3. Use of chromium ore waste, Bulqizë

Tailings which are deposited in dams near the processing facilities still contain useful elements and with new technological flow sheets and equipment they serve as a secondary raw material source, which, through recycling processes, will produce mineral products. (Figure 4) The recycling processes of chromium tailings by using new flow sheet with regrinding and treatment of fine particles have good results in producing chromium concentrate for export. The recycling processes of copper tailings by using new flow sheet with regrinding by vertical mills have good results in producing copper concentrate, even in the case of tailing with grade of Cu up to 0,35 % Cu. Tailing comings from recycle are then re-deposited in the same dam or in new ones to achieve the total rehabilitation of the area where they are deposited (Bode A. et al. 2009) [5]. 37

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Tailing exploitation at Bulqiza dam

Fushë Arrës Tailing exploitation used in the recycle process in Copper processing plant

Bulqizë Tailing exploitation used in the recycle process in Chromium processing plant

Figure 4. Tailing exploitation for recycling

4. Rehabilitation of mining waste areas

Currently, there are a lot of mining areas where these mineral wastes are out of control (except for some facilities that are currently working or some dams where the rehabilitation process has taken place in Reps, Rubik, Fushë Arrës). They do have impact on the environment in the aspect of ecosystem damages, surface and groundwater pollution, panorama, the space they occupy affecting the level of forests, the risk of landslides or hinks, etc. (Table 1, figure 5) [6]. Of the limestone processing facilities (45 built before the '90s and over 130 built in these 25 years), the waste part is considered as inert material, in many cases it has been used as a filler material and in addition to Figura 4. Pamje[3]. te mbetjeve te ngurta ngathe proceset e shfryte the panoramic effect, their polluting effect in the environment is limited However, for a minerare small part, need for a rehabilitation process is immediate as is the case of waste in the Fushë Krujë region.

Table 1. Data on mining and sterile processing facilities that they have generated Current Sterile Content of useful Mineral processing The Mineral production (waste) Location elements facilities district (ore) of sterile stocks (%) (tons / year) (ton) Gal 41Selection plant Dibër Chrome closed No data No data Bulqiza LucanSelection plant Mat Chrome closed No data No data Krastë The object of mixing Lucan Mat Chrome closed No data No data and averaging Krastë The object of mixing Laç Kurbin Chrome closed No data No data and averaging The object of mixing Milot Kurbin Chrome closed No data No data and averaging Suspension Klos Mat Chrome Reconstructed No data No data enrichment plant Enrichment Factory Bulqizė Dibër Chrome 17.000 2 300 000 8-10 % Cr2O3 Enrichment Factory Kalimash Kukës Chrome closed 0 0 Enrichment Factory Krastë Mat Chrome closed 162 100 10-12 % Cr2O3 Ferrochrome plant Burrel Mat Chrome 18 700 330 000 8-8.5 % Cr2O3 Ferrochrome plant Elbasan Elbasan Chrome 37 200 240 000 8-8.5 % Cr O3 Figura 5. Pamje te depozitimit te mbetjeve te2 ngurta minerare ne fushe Slag sorting plant Shëngjin Lezhë Copper closed 0 0 Enrichment Factory Golaj Kukës Copper closed 349 691 0.17%Curruges se transportimit Enrichment Factory Fushë-Arrës Puka Copper 240.000 3 103 361 0.22%Cu No.1 and No.2 FAKULTETI I GJEOLOGJISË DHE I MINIER Fabrika e Pasurimit Reps Mirdita Copper closed Rruga3Elbasanit, 695 067 Tiranë, Tel.: +355 0.18% Cu Adresa: 4 2375246/5, web: www.fgjm.ed Nr.1 dhe Nr.2 38

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590 Enrichment Factory Mjedë Enrichment Factory Rëshen Enrichment Factory Kurbnesh Enrichment Factory Rehovë Copper Smelting Plant Laç Copper Refining Plant Rubik Copper Smelting Plant Rexhepaj Copper Refining Plant Rubik

Shkodër Mirdita Mirdita Korçë Kurbini Kurbini Kukës Mirdita

vol. 28, issue 2 / 2022 pp. 37-41 Copper Copper Copper Copper Copper Copper Copper Copper

closed 44 552 0.14% Cu closed 444 588 0.19%Cu closed 3 582 649 0.17%Cu closed 611 037 0.15%Cu closed No data No data closed No data No data closed No data No data closed No data No data In Copper Wires Factory Shkodër Shkoder Copper No data No data reconstruction Enrichment Factory Guri i Kuq Pogradec Iron-Nickel closed 2 600 000 No data Fraction-Fraction Prenjas Librazhd Iron-Nickel closed 1 800 000 No data Factory Nickel Liquidation Elbasan Elbasan Iron-Nickel closed No data No data Plant (U-12) Metallurgical Plant Elbasan Elbasan Iron-Nickel closed No data No data Enrichment Factory Valias Tiranë Coal Stone closed 5 970 000 Calorific Power 400 kk/kg. Enrichment Factory Memaliaj Tepelenë Coal Stone closed 4 520 000 Calorific Power 596 kk/kg. Enrichment Factory Maliq Korce Qymyr Guri closed 800 000 Fuqia Kalorifike 400 kk/kg. Heavy Sand Enrichment (Rushbull) Minerals Rare Durres closed No data No data Plant Durrës Soils (Zircon, Hafmium,etc.) Talc Enrichment Plant Korçë Korçë Talc closed No data No data Phosphorite Memaliaj Tepelena Phosphorite closed No data No data Flourishing Plant Quartz-Olivinite Laç Kurbin Kuarci closed No data No data Enrichment Company Feldspat enrichment GraniteTirana Tirana closed No data No data plant feldshpati Average-ExportPort-Durrës Durres All minerals closed No data No data Import Affiliate TOTAL 30 553 045 valued sterile tons

Figure 5. Dam in Kurbnesh

Waste deposits of coal enrichment plants have faster self-regenerating capacity for the very content of elements in them, which has been observed in some dams or deposits of Memaliaj mine (Figure 6) (AKBN. 2015) [1]. 39

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Figure 6. Vegetation that has covered mining waste at Memaliaj mine

Quantitative-qualitative assessment of stocks of mineral waste and sterile dams, which are currently located near closed mines and factories or in operation is the starting point for studies and projects for their recycling opportunities (use of modern methods of hydrometallurgical enrichment, biolivation, etc.) and the avoidance of pollution, which they cause in the surrounding environment, determining the manner of final rehabilitation of the areas where these sterile wastes are deposited (Figure 4) (AKBN. 2017). Only for the three copper factories of Reps, Kurbnesh and Rrëshen the land area that can be obtained after complete rehabilitation is about 20 ha (194 900 m2) (Bode A. 2009) [5]. It is true that from the past we inherit an aggravated environmental situation in the mining industry [7]. This is because:  The full legal framework for the protection of the environment and health was lacking;  The only priority was given only to the production and growth of industrial activities;  The applied technologies and their work were not performing;  Lack of information on clean technologies;  Very little impact on the environment was assessed and in the mining projects it represented an insignificant part. Currently, mining and environmental legislation is almost entirely in line with the European Community directives. For mining waste, the 2006 directive on solid waste was adopted during the adoption of the new mining law and a series of bylaws were drafted in this regard; every year the Annual Environmental Report for the mining industry is drafted, so the information in this regard is added [8]. But the same situation is not observed in the case of the projects related to mineral waste, whether development or recycling and rehabilitation are concerned; it is important for us to design clear and accurate programs and projects for recycling, pollution preventing and rehabilitating the contaminated areas or surfaces. In the context of rehabilitation, recycling processes take on a special importance, as they generate revenue, reduce the amount of waste that is deposited, and provide opportunities for sterile or previous waste to enter the economic circulation and the landfill to be rehabilitated for use in other purposes, even in industrial purposes [8]. In terms of rehabilitation, it is time to start projects for the closed mining areas, in the case of which a part of the income from environmental rehabilitation should be provided for those closed mining facilities. For such projects, the combining of these revenues with funding that has not been lacking so far from international institutions and partnerships will enable the holders to make the rehabilitation process successful [6]. In this regard, it is definitely required to increase the level of social awareness regarding mining pollution based on the concept of sustainable development of the country. It is necessary to understand the fact that improvement in the mining environment requires the training of many people, employees, technologies, funds and time. 40

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5. Conclusions The environmental management system should include a well-defined coordination and approach from the part of mining and environmental institutions. Environmental monitoring is also important here, the results of which should be transparent to civil society and the public. Recognizing the potential of mineral waste pollution and environmental measures in terms of recycling and rehabilitation would help prevent environmental disasters, but would make mineral waste a no less important part for the development and economic well-being of areas where they are deposited. Promotion and encouragement of foreign investments, through the application of clean technologies for their treatment (especially for copper sterilizers that in addition to the copper element have rare elements such as gold and silver) would guarantee profit and reduction and possible elimination of environmental pollution [6]. Environmental management best practices represent a process of continuous improvement, which enables performance-enhancing operations in specific operations over time. These improvements can be made by changes in legislative requirements, public trends, the opinion of mining companies, and the development of new improved technology. Minimizing the environmental impact of a mining operation depends on sound management practices and in this context an important part of it is the modern management of mining waste

References [1] National Agency of Natural Resources, 2017 Annual reports on mining activity 2011- 2017 http://www.akbn.gov.al/wpcontent/uploads/2015/02/Broshura_Minierat.pdf [2] Working group, ITNPM, 2006 Solid waste of metal mines in Albania - Project [3] Bode A, et al., 2010 Mining Residues Around Lake Ohrid, Journal of Mining and Metallurgy, Section A: Mining, Volume 46 Number (1) ISSN 1450-5959. [4] Mati S., Bode A., 2011 NeË floË-sheet for tailing recycling of the chromium dressing plant of Bulqiza, Vol II pg 729, XIV BMPC Balkan Mineral Processing Congress- Tuzla- Bosnia & Herzegovin, ISBN 978-9958-31-038-6; June 14-17. [5] Bode A., et al., (2009) Post - transition environmental assessment in Albania, Volume II, pp 673. XIII BMPC Balkan Mineral Processing Congress- Bucharest-Romania, ISBN 978-973-677-159-0; ISBN 978-973-677-161-3, 14-17June. [6] Mati S., 2011 Albania- An emerging country, Mining Journal July 29, 2011, p. 14, www.miningjournal.com [7] Mati S., 2009 Strategy for industrial minerals Albania SARMA - EC- Program. Meeting Sustainable Aggregates Resource Management European Territorial Co-operation 2007 - 2013 Split, Croatia March 2009 [8] Mati S., 2010 Mining policy for a sustainable development of mining activities, SARMA - ECProgramme. Workshop in Tirana, Albania 2010

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Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590 vol. 28, issue 2 / 2022, pp. 42-48

GOLD: PROPERTIES, MINERALS, ALLOYS, USES AND RECYCLING Ioan-Lucian BOLUNDUȚ1* 1

University of Petrosani, Petrosani, Romania, ibol1947@gmail.com

DOI: 10.2478/minrv-2022-0013 Abstract: The paper presents a brief history of Bronze Age gold to the Middle Ages, as well as its properties, minerals and deposits, alloys, uses and recycling. Keywords: gold, gold ore, gold use, recycling 1. Short history Gold has always fascinated people, enriching some or ruining others, provoking wars or facilitating alliances, and leading to the rise of some empires or the disappearance of others. It has been so present in human life that it is mentioned 417 times in 189 verses of Holy Scripture, beginning with Genesis 2:11 and ending with Revelation 21:18. It was one of the three gifts that the Magi gave to Baby Jesus, along with myrrh and frankincense: gold like a king, incense like a God, and myrrh like a man who was to die and be embalmed. U.S. researchers, whose professional integrity cannot be questioned, say there is evidence of the use of gold as early as 6,000 years ago, citing the following more important data [1]: 4000 B.C. A culture, centered in what is today Eastern Europe, begins to use gold to fashion decorative objects. The gold was probably mined in the Transylvanian Alps or the Mount Pangaion area in Thrace. 3000 B.C. The Sumer civilization of southern Iraq uses gold to create a wide range of jewelry, often using sophisticated and varied styles still worn today. 2500 B.C. Gold jewelry is buried in the Tomb of Djer, king of the First Egyptian Dynasty, at Abydos, Egypt. 1500 B.C. The immense gold-bearing regions of Nubia make Egypt a wealthy nation, as gold becomes the recognized standard medium of exchange for international trade. The Shekel, a coin originally weighing 11.3 grams of gold, becomes a standard unit of measure in the Middle East. It contained a naturally occurring alloy called electrum that was approximately two-thirds gold and one-third silver. 1350 B.C. The Babylonians begin to use fire assay to test the purity of gold. 1200 B.C. The Egyptians master the art of beating gold into leaf to extend its use, as well as alloying it with other metals for hardness and color variations. They also start casting gold using the lost-wax technique that today is still at the heart of jewelry making. Unshorn sheepskin is used to recover gold dust from river sands on the eastern shores of the Black Sea. After slucing the sands through the sheepskins, they are dried and shaken out to dislodge the gold particles. The practice is most likely the inspiration for the „Golden Fleece”. 1091 B.C. Little squares of gold are legalized in China as a form of money. 560 B.C. The first coins made purely from gold are minted in Lydia, Asia Minor. 344 B.C. Alexander the Great crosses the Hellespont with 40,000 men, beginning one of the most extraordinary campaigns in military history and seizing vast quantities of gold from the Persian Empire. 300 B.C. Greeks and Jews of ancient Alexandria begin to practice alchemy, the quest of turning base metals into gold. The search reaches its pinnacle from the late Dark Ages through the Renaissance. 218–202 B.C. During the second Punic War with Carthage, the Romans gain access to the gold mining region of Spain and recover gold through stream gravels and hardrock mining. 58 B.C. After a victorious campaign in

Corresponding author: Ioan-Lucian Bolunduț, Prof.Ph.D / University of Petrosani, Petrosani, Romania (University of Petrosani, 20 University Street, ibol1947@gmail.com) *

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Gaul, Julius Caesar brings back enough gold to give 200 coins to each of his soldiers and repay all of Rome’s debts. 50 B.C. Romans begin issuing a gold coin called the Aureus. 476 A.D. The Goths depose Emperor Augustus, marking the fall of the Roman Empire. 600–699 A.D. The Byzantine Empire resumes gold mining in central Europe and France, an area untouched since the fall of the Roman Empire. 742–814 A.D. Charlemagne overruns the Avars and plunders their vast quantities of gold, making it possible for him to take control over much of Western Europe. 1066 A.D. With the Norman Conquest, a metallic currency standard is finally re-established in Great Britain with the introduction of a system of pounds, shillings, and pence. The pound is literally a pound of sterling silver. 1250–1299 A.D. Marco Polo writes of his travels to the Far East, where the „gold wealth was almost unlimited”. 1284 A.D. Venice introduces the gold Ducat, which soon becomes the most popular coin in the world and remains so for more than five centuries. 1284 A.D. Great Britain issues its first major gold coin, the Florin. This is followed shortly by the Noble, and later by the Angel, Crown, and Guinea. 1377 A.D. Great Britain shifts to a monetary system based on gold and silver. 1511 A.D. King Ferdinand of Spain says to explorers, “Get gold, humanely if you can, but all hazards, get gold,” launching massive expeditions to the newly discovered lands of the Western Hemisphere.

2. Properties of gold Gold was one of the first metals used by man, along with copper, the name being given by the Romans (aurum), where aura means gold, brightness or light. It has a bright yellow color, warm and pleasant, being the most malleable and ductile of all metals. So malleable that a 1 m2 semi-transparent sheet can be beaten from a gram of gold and so ductile that it can be pulled into extremely small thick wires. It is a good conductor of heat and electricity, melts at 1,064°C, boils at 2,970°C and has a density of 19.30 g/cm 3, close to that of tungsten (19.25). As a result, tungsten was used to counterfeit gold, by plating it with noble metal or by drilling a gold ingot and plugging the hole with a tungsten rod. As a miscellaneous fact, of all metals, the lowest density is lithium (0.53 g/cm3) and the highest is osmium (22.59 g/cm3). Like all metals, solid gold has a crystalline structure, meaning that its atoms are distributed in the nodes of an elementary crystal cell called a cubic lattice with centered faces. This network consists of 14 atoms, of which 8 in the corners of the elementary cell and 6 in the centers of the faces of the cube. The density of the atoms in the network is 75% (Fig.1). Gold is resistant to the oxidizing and corrosive action of most chemicals, being attacked only by royal water, a mixture of nitric acid and hydrochloric acid, in a volume ratio of 1: 3. It is insoluble in nitric acid, which dissolves silver and base metals, a property used for refining gold and confirming it in various metal objects (acid test). It dissolves in alkaline sodium cyanide solutions, a property on which its extraction from poor ores Figure 1. Crystal lattice of gold is based by the cyanide process, invented in 1887 in Glasgow, which ensures an extraction yield of 97%. Also based on this property is the coating of metal objects with a thin layer of gold, through the electrochemical galvanizing process. Based on this method, some workers in the electrolytic refining sectors of gold during communism in our country have subtilized significant amounts of noble metal through a simple disarming trick. The operator only had to own a gold cigarette case, which he declared at the entrance in exchange, then tied it to the cathode of the electrolysis tank. A layer of 24 carat gold was quickly deposited on the cigar case. No one weighed the tobacconists at the entrance or exit of the exchange, so modern holoangars only had to turn to complicit jewelers to supply them with other tobacconists. This object was used because it had a larger volume and mass than jewelry, less worn by men. Gold dissolves in mercury, forming a solid solution called amalgam, which is an older extraction process with an extraction yield of 60–75%. The amalgam is heated in

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a retort, the mercury is evaporated and a spongy material containing gold and silver, called burnt gold, is obtained [2, 3, 4, 5]. The mechanical properties of gold are weak except for plasticity. Instead, the technological ones are goods, it can be processed by casting, plastic deformation and light gluing, using copper or silver, and as a protective flux borax. 3. Gold minerals and deposits Gold is found in the earth's crust, especially in its native state, but also in the form of combinations with silver, platinum and tellurium. The main minerals of gold are [6]: • Calavera (AuTe2): Au – 43,6%, Te – 56,4%, Ag – 1%. • Silvanit [(AuAg)2Te4]: Au – 34,37%, Ag – 6,27%, Te – 59,36%. • Nagyágit [Pb3(PbSb)3S6(AuTe)3]: Au – 8,18%, Te – 15,89%, Sb – 5,06%, Pb – 60,22%, S – 10,65%. • Krennerit (Au3AgTe8): Au – 34,37%, Ag – 6,27%, Te – 59,36%. • Petzit (Ag3AuTe2) : Au – 25,38%, Ag – 41,71%, Te – 32,90%. All these minerals were discovered in the sec. XIX in the Săcărâmb gold deposit, except for the calavera that was highlighted in 1861 in the Calaveras region of California. The silvanite was discovered in 1835 by the Swiss geographer and crystallographer Lois Necker de Saussure, the petzite in 1842 by the Austrian chemist Wilhelm Petz, the nagyágite in 1845 by the Austrian naturalist Franz Müller, and the krennerite in 1848 by the Hungarian mineralogist Joseph Krenner. Two types of deposits are known to contain significant amounts of gold, namely primary deposits and secondary deposits. The primary deposits are of hydrothermal origin, being associated with quartz and pyrite (stupid gold!) and are presented in the form of veins or as gold scattered in rocks. They were formed by the crystallization of hot solutions produced in the process of cooling magma from inside the Earth. The secondary deposits were formed by the erosion in the superficial area of the terrestrial crust of the filonian or disseminated type deposits, accumulating in the sedimentary deposits at the level of the alluvial terraces or in the sediments at the bottom of the rivers and seas. In addition to gold, there are other metals or precious stones in these alluvial deposits with densities higher than those of quartz (2.65) with which they are associated: uranium, thorium, tin, zirconium, titanium, ruby, sapphire and diamond. As with other useful substances, these alluvial accumulations become ore deposits. The alluvial deposits found along the watercourses were the main sources of gold in antiquity for Egypt, Mesopotamia, Lydia (today in Turkey), Persia, India and China.

Figure 2. Formation of an alluvial deposit

Experts estimate that the world's gold reserves are currently about 50,000 tons, of which almost 70% are located in 10 countries (Table and Fig.3). In Romania, the gold mines were closed, as unprofitable, in 2006, but in the basement of the country there are still important reserves in the Gold Quadrangle of the 44

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Apuseni Mountains and in the Baia Mare mining basin. In the absence of official data, it is difficult to assess the gold reserve left in the basement, which is certainly quite significant. In Romania, about 2,070 tons of gold were extracted over time, as follows: pre-Roman period (before 106 A.D.) – 10%; Roman period (106-270) – 24%; the Middle Ages (270-1492) – 24%; period of the Habsburg Empire (1492-1918) – 27%; the interwar period (1918-1945) – 4%; the communist period (19451989) – 9%; post-communist period (1989-2006) – 2%. The largest amount of gold on the territory of Romania (actually from Transylvania, Banat and Maramureş) was extracted in the period 1492–1918 by the Habsburg Empire (27%). No. crt. 1. 2. 3. 4. 5.

Country Australia Russia South Africa USA Indonesia

Reserves, t

No. crt.

10.000 5.300 3.200 3.000 2.600

6. 7. 8. 9. 10.

Country

Reserves, t

Brazil Peru China Canada Uzbekistan

2.400 2.100 2.000 1.900 1.800

Figure 3. World's major gold reserves [7,8]

4. Gold alloys Because gold is too soft to withstand long-term use, it is alloyed with other metals to increase hardness and wear resistance. Also, the alloying elements lead to a variety of shades or colors. The amount of gold in an alloy equal to 24th of the total mass is called the carat. So 24 carat gold is pure gold. Carats

% Au

99,99

91,67

Thousand ths

999

917

83,34 75,01 66,68 58,35 833

750

667

584

12 50,02 500

41,69 33,36 25,03 417

337

250

16,7

8,37

167

Silver and copper are the main metals with which gold is alloyed, but it can also be alloyed with platinum, nickel, zinc, manganese and palladium, obtaining alloys with different destinations, properties and colors. Only 24 and 18 carat alloys are recognized as universal. The others are considered to be specific to the culture of certain countries or regions of the world, as follows: they have 22k – UK, Asia; Au 20k – Asia; They have 15k (625 ‰) – Great Britain, Australia, New Zealand; Au 14k – Europe, Asia, USA, Turkey; At 12 k – USA, South Africa; Au 10k – USA, South Africa; Au 9k (375 ‰) – Europe, Australia, New Zealand; Au 8k – Germany. 45

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4.1. Gold alloys for jewelry Pure gold cannot be used in the manufacture of jewelry, having a very high malleability. To increase the hardness and resistance to breakage and wear, it is especially alloyed with copper and silver, but also with zinc, iron or aluminum. The first jewelry made of gold and silver alloys appeared in ancient and then preColumbian civilizations. Today, most gold jewelry is made of 18 carat alloys, with 9 different shades: ● Yellow gold: Au – 75%, Ag – 12.5%, Cu – 12.5%. ● Rose gold: Au – 75%, Cu – 20%, Ag – 5%. ● White gold: Au – 75%, Ag – 18.5%, Zn – 5.5%, Cu – 1%. ● Gray gold: Au – 75%, Fe – 17%, Cu – 8%. ● Red gold: Au – 75%, Cu – 25%. ● Green gold: Au – 75%, Ag – 25%. ● Blue gold: Au – 75%, Fe – 24.4%, Ni – 0.6%. ● Purple gold: Au – 75%, Al – 21% (can be assimilated with Au 18k). ● Black gold: White gold plated by rhodium plating. Currently about 53% of world gold production (3,300 t/year) is used in jewelry manufacturing. As nickel used in the alloys of watch cases and bracelets has been found to cause contact dermatitis in one in ten people, the European Union recommends giving it up. 4.2. Dental gold alloy Dental alloys are standardized internationally by the standards established by ISO 22674:2016. Based on this standard, the following dental gold alloys have been standardized in Germany [9]: Type A B S M M0

Gold, % 87,5 75,8 79,3 74,8 65,6

Silver, % 11,5 15,0 12,3 13,5 14,0

Platinum, % – 1,4 0,3 4,4 8,9

Palladium, % 1.0 3,3 1,6 2,0 1,0

Copper, % – 4,1 5,5 4,1 10,0

Zinc, % – 0,4 1,0 1,2 0,5

They melt at 860–1,080°C, have a breaking strength of 30–59 kg/mm2, a density of 15.6–17.4 g/cm3 and a relative elongation at break of 34–43%. 5. Uses of gold Due to its rarity, beauty and properties, gold has been used as an exchange since ancient times. Early transactions were made with gold or silver pieces, easily portable and divisible. Later, gold coins were minted, which circulated even after the printing of paper banknotes. The banknotes were backed by a safekeeping stockpile of gold, as the United States did by using the gold standard, storing a quantity of precious metal for paper dollars in circulation. According to this standard, anyone could exchange the banknote with its gold plating, but the process proved to be too cumbersome and was abandoned. Gold coins are no longer used in financial transactions, but are popular ways of investing or are issued for commemorative purposes. Today, much of the world's gold reserves are held in national banks in the form of bullion, so that in the event of a financial crisis it can be converted into foreign currency, guaranteeing the liquidity of the holding countries. The official gold reserves of over 100 tons were thus distributed in March 2022 [10]: Country USA Germany Italy France Russia China Switzerland Japan India

Reserves, t 8 133 3 358 2 452 2 436 2 302 1 948 1 040 846 760

Country

Reserves, t

Portugal Kazakhtan Uzbekistan Saudi Arabia United Kington Lebanon Spain Austria Thailand

383 368 337 323 310 287 280 280 244 46

Country Venezuela Philippines Singapore Brazil Sweden South Africa Egypt Mexico Libya

Reserves, t 161 156 154 130 126 125 125 120 117

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612 431 424

vol. 28, issue 2 / 2022 pp. 42-48

Poland Belgium Algeria

229 227 174

Greece South Korea Romania

114 104 104

Gold also has many industrial uses, the most important being in the manufacture of electronic products. They operate with very low voltages and currents, which can be easily interrupted by corrosion at the contact points. With very good electrical conductivity and corrosion resistance, gold is an extremely reliable element used in connectors, switching contacts, printed circuits, relays, solder joints and wires or conductive strips. All of this can be found in mobile phones, standard computers, laptops, camcorders, memory cards, global positioning systems (GPS) and satellites. About 200 tons of gold are consumed annually for the manufacture of these products, from which almost nothing is recovered. Almost a billion mobile phones are produced every year, with a lifespan of about two and very few being recycled. The cost of gold in a mobile phone is 50 cents, so recovering it is not cost effective. The same is true of other electronic products. The construction of satellites or spacecraft, in which the possibility of lubrication, maintenance and repair is ruled out, could not be achieved without the use of gold, which is a reliable conductor and connector. Many parts of spacecraft are also covered with gold-plated polyester foil, which reflects infrared radiation, ensuring the stability of the interior temperature. Without this protection, the dark parts of the vehicles would absorb too much heat. Gold also reduces the friction of moving mechanical parts, replacing organic lubricants, which would volatilize in the presence of cosmic radiation. With a very low shear strength, the gold atoms slide easily on the surfaces of moving parts, ensuring very good lubrication. Gold has applications even in medicine, not only in dentistry, but also as a medicine. Injections with weak solutions of sodium aurothiolate (C4H4AuNaO5S) or aurothioglucose (C6H11AuO5S) are used to treat rheumatoid arthritis, pemphigus vulgaris (autoimmune disease that causes fluid bubbles and skin ulcers) and dermatitis. The particles of a radioactive gold isotope are implanted in tissues for the treatment of certain types of cancer. Also, small amounts of gold are used to treat lagophthalmia, a condition that is manifested by the inability of the upper eyelid to cover the eye, which remains open during sleep. The gravitational force of the gold particles helps the eyelid to close completely. Many surgical instruments, electronic equipment, and life support devices contain small amounts of gold, which is extremely reliable and compatible with living tissues. The list of gold uses can continue with the medals of the winners of major sports competitions and school Olympics, Nobel, Oscar, Grammy or other awards, but also with some church objects of worship. The snobbery of the rich has gone so far that some people drink champagne with 24-carat (0.000125 mm) inert organic gold microparticles at exorbitant prices or order gold dusted food, especially in luxury restaurants in Saudi Arabia, France and the USA. Saudi princes drive gold-plated luxury cars, which defies any ethics. It is estimated that today there are about 200,000 tons of gold above the ground, which would fill a cube with a side of 21.8 meters. 6. Gold recycling It is estimated that about 1,100 tons of gold are recycled annually, which is 33% of the world's 3,300 tons of consumption. 90% of jewelry, ingots, coins and dental gold and 10% of industrial waste are recycled. Recovering gold from industrial waste costs less than extracting it from ores and is less polluting, but 2/3 of what could be recycled is dumped in landfills. There are countries that do not have gold deposits, but recover the precious metal from waste, covering their domestic consumption. Most European industrial waste from which gold could be mined, as well as other deficient metals, is shipped for nothing to Asia or Africa, losing billions of euros. Country China India Turkey Italy United States

Recycled gold, t 222,1 103,1 77,4 67,5 56,4

Country Japan Egypt United Kington Russia South Korea

Recycled gold, t 48,2 45,9 40,7 37,6 32,9

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References [1] * * *, 2004 The History of Gold, National Mining Association. Washington [2] Bolunduţ I.L., 2017 The monography of the village Bucium – Alba (in Romanian), Altip Publishing, Alba Iulia [3] Lăzărescu I., Brana V., 1972 Gold and silver (in Romanian), Technical Publishing, Bucureşti [4] Popescu C.Gh., Tămaş-Bădescu S., Tămaş-Bădescu G., Bogatu L., Neacşu A., 2007 The economic geology of gold (in Romanian), AETERNITAS Publishing, Alba Iulia [5] Verdeş Gr., 2010 Das Gold- Museum in Brad, Silber und Salz in Siebenbürgen (in German), Bochum, Bd. X/1, S. 571–580. [6] Ghiţulescu T.P., Socolescu M., 1941 Étude géologique et minière des Monts Métallifères (Quadrilatère aurifère et régions environnantes) (in French), Anuarul Institutului Geologic al României, Tome XXI, pag. 181–464. [7] * * *, 2021 GFMS Gold Survey [8] * * *, 2021 World Gold Council Report [9] * * *, 2016 ISO 22674:2016. [10] * * *, 2022 Gold Reserves by Country 2022 – Word Population Review.

This article is an open access article distributed under the Creative Commons BY SA 4.0 license. Authors retain all copyrights and agree to the terms of the above-mentioned CC BY SA 4.0 license.

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590 vol. 28, issue 2 / 2022, pp. 49-53

ANALYSIS OF ORIENTATION ACCURACIES IN UNDERGROUND POLYGONAL ROUTES Ofelia-Larisa FILIP1*, Anca Daniela FILIP2 1

Mining Engineering, Surveying and Civil Engineering Department, University of Petrosani, Petrosani, Romania, larisafilip@yahoo.com 2 Ph.D student, University of Petrosani, Petrosani, Romania

DOI: 10.2478/minrv-2022-0014 Abstract: Topography has an important role in the realization of underground mining works, hydro-technical constructions, roads, etc. Appropriate topographic measurements and processing are required to trace these objectives in the necessary safety and efficiency conditions. An appropriate topographic basis must first be established for which scientific analyzes focusing mainly on topographical guidance elements are required. It is considered an independent polygonal route, easy to achieve and with superior quality effects. Keywords: topography, accuracy, underground routes, polygon 1. The importance and purpose of the paper The topographical base of support has an important role for tracing underground works. The topographic base may be dependent (linked to the surface geodetic network), but may be independent (free from orientation). This eliminates errors in the transmission of surface orientation underground and increases the accuracy of underground directions. Therefore, the propagation of orientation errors in a polygonal path (with two fixed points) is analyzed below. 2. The content of the paper End points A, B (fig. 1) of the underground polygon are transmitted from the surface.

Fig. 1

Larisa-Ofelia Filip, Assoc.prof. eng., Ph.D / Mining Engineering, Surveying and Civil Engineering Department, University of Petrosani, Petrosani, Romania (University of Petrosani, 20 University Street, larisafilip@yahoo.com) 49

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Without taking into account the design errors (they have a negligible influence on the orientation of the sides of the polygon), the analysis to be performed takes into account the influence of the measurement errors of the angles and sides of the polygon. The quadratic error of the orientation of the sides in an underground polygonation as a function of the angle measurement errors is expressed by the relation [1], [2]: 𝜕𝜃 ) 𝜕𝛽𝑖

𝑚𝜃2𝛽 = ∑𝑛−1 𝑖=1 (

𝑚𝛽2𝑖

(1)

but: θ = θAB − τAB + 𝜏

(2)

where: θAB - orientation of the AB direction in the general reference system; τAB - orientation of the direction AB in the particular reference system; τ - side orientation in the particular system. but how: 𝜕𝜃𝐴𝐵 =0 𝜕𝛽 it results: 𝜕𝜃 𝜕𝛽

𝜕𝜏 𝜕𝛽

on the other hand: tgτAB =

𝜕𝜏𝐴𝐵 𝜕𝛽

(3)

yB′ xB′

and: 𝑑𝜏𝐴𝐵 𝑐𝑜𝑠2 𝜏𝐴𝐵

′ ′ ′ ′ 𝑥𝐵 𝑑𝑦𝐵 −𝑦𝐵 𝑑𝑥𝐵 ; ′2 𝑥𝐵

𝑥𝐵′ = 𝑐 𝑐𝑜𝑠𝜏𝐴𝐵 𝑦𝐵′ = 𝑐 𝑠𝑖𝑛𝜏𝐴𝐵

or: 𝑑𝜏𝐴𝐵 𝑐𝑜𝑠2 𝜏𝐴𝐵

′ ′ 𝑐 cos 𝜏𝐴𝐵 𝑑𝑦𝐵 −𝑐 sin 𝜏𝐴𝐵 𝑑𝑥𝐵 𝑐 2 𝑐𝑜𝑠2 𝜏𝐴𝐵

where from: 𝑐 𝜏𝐴𝐵 = 𝑐𝑜𝑠𝜏𝐴𝐵 𝑑𝑦𝐵′ − 𝑠𝑖𝑛𝜏𝐴𝐵 𝑑𝑥𝐵′ or: 𝑐

𝜕 𝜏𝐴𝐵 𝜕𝛽

′ 𝜕𝑦𝐵 𝑐𝑜𝑠𝜏𝐴𝐵 𝜕𝛽

−

′ 𝜕𝑥𝐵 𝑠𝑖𝑛 𝜏𝐴𝐵 𝜕𝛽

(4)

From the figure 1, it is observed that: ′ 𝜕𝑥𝐵 𝜕𝛽

= −𝑅 𝑠𝑖𝑛𝛾;

′ 𝜕𝑦𝐵 𝜕𝛽

= 𝑅 𝑐𝑜𝑠𝛾

(5)

With these we can write: 𝑐 𝜕𝜏𝐴𝐵 𝜕𝛽

= 𝑅 𝑐𝑜𝑠(𝜏𝐴𝐵 − 𝛾)

𝑅 𝑐𝑜𝑠(𝜏𝐴𝐵 − 𝛾) is the projection of the radius R on the line AB and is denoted by R′ [3].

(6)

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Accordingly: 𝜕𝜏𝐴𝐵 𝜕𝛽

R′ 𝑐

(7)

And relation (3) is: 𝜕𝜃 𝜕𝛽

𝜕𝜏

= 𝜕𝛽 −

𝑅′ 𝑐

(8)

Using the equality (8) the errors of the orientation of the sides can be established in this way [4]: First side orientation error 𝜏1 = 0;

In this case and as a consequence: 𝜕𝜏1 = 0; 𝜕𝛽𝑖

𝑖 = 1,2 … , 𝑛 − 1

It results from (8): 𝜕𝜃1 𝛽𝑖

=−

𝑅𝑖 𝑐

(9)

With the sizes in (9), the equality (1) becomes: 𝑚𝜃21𝛽 = 𝑘 ∑ 𝑅𝑖2

(10)

It was noted: 𝑚𝛽 2 𝑘=( ) 𝑐 Second side orientation error In this case [5]: 𝜏2 = 𝜏1 + 𝛽1 ± 200 𝑔 and as a consequence: 𝜕𝜏2 = 1; 𝛽1

𝜕𝜏2 = 0; 𝛽𝑖

It results:

𝑖 = 2,3, … , 𝑛 − 1

𝜕𝜃2 𝑅1′ =1− 𝜕𝛽1 𝑐 𝜕𝜃2 𝑅𝑖′ =− ; 𝜕𝛽𝑖 𝑐

𝑖 = 2, … , 𝑛 − 1

With these we can write: 𝑛−1

𝑚𝜃22𝛽

= 𝑘 ∑ 𝑅𝑖 + 𝑘𝑐(𝑐 − 2𝑅𝑖′ ) 𝑖=1

or: 2 2 𝑚2𝛽 = 𝑚1𝛽 + 𝑘𝑐(𝑐 − 2𝑅𝑖′ )

(11)

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On long polygonal routes 𝑐 − 2𝑅𝑖′ < 0 and as a consequence: 𝑚𝜃2𝛽 < 𝑚𝜃1𝛽 Side orientation error i By generalization one can write: ′ 𝑚𝜃2𝑖𝛽 = 𝑚𝜃21𝛽 + 𝑘𝑐 ∑𝑖−1 𝑗=1(𝑐 − 2𝑅𝑗 )

(12)

or: 𝑖−1

𝑚𝜃2𝑖𝛽

𝑚𝜃21𝛽

+ 𝑘𝑐 [(𝑖 − 1)𝑐 − 2 ∑ 𝑅𝑗 ] 𝑗=1

The influence of side measurement errors on their orientations shall be determined taking into account the equality of: 𝜃 = 𝜃𝐴𝐵 − 𝜏𝐴𝐵 + 𝛽 and 𝜕𝜃 𝜕𝜏𝐴𝐵 = ; 𝜕𝑠 𝜕𝑠

𝜕𝜃𝐴𝐵 = 0; 𝜕𝑠

With these we can write:

𝜕𝛽 =0 𝜕𝑠

𝑛

𝑚𝜃2𝑠

𝜕𝜃 2 = ∑ ( ) 𝑚𝑠2𝑖 𝜕𝑠𝑖 𝑖=1

but: 𝜕𝜃 𝑠𝑖𝑛𝜀𝑖 =− 𝜕𝑠𝑖 𝑐 Accordingly: sin 𝜀𝑖 2 2 ) 𝑚𝑠𝑖 𝑐

𝑚𝜃2𝑠 = ∑𝑛𝑖=1 (

(13)

Influence of errors in measuring angles and distances in the calculation of guidelines results from cumulative relationships (12) and (13). You get: sin 𝜀𝑖 2 2 ) 𝑚𝑆1 𝑐

2 𝑛 ′ 𝑚𝜃𝑖 = ±√𝑚1𝛽 + 𝑘[(𝑖 − 1)𝑐 − 2 ∑𝑖−1 𝑗=1 𝑅𝑗 ] + ∑𝑖=1 (

(14)

3. Conclusions The analysis performed were completed through relationships that were easy to apply in practice. The sizes used can be obtained by geometrically representing the polygonal path. The orientation of underground works in the process of their technical execution is controllable, precise and safe. The topographic elements of interest are located in the development points of the topographic base.

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References [1] Dima N., Pădure I., 1997 Mine surveying (in Romanian), Corvin Publishing, Deva [2] Dima N., e.a., 1999 Error theory and least squares method (in Romanian), Universitas Publishing, Petroșani [3] Cucăilă M., Cucăilă S., 2021 Evaluation of topographic works necessary for underground mining activities (in Romanian), Universitas Publishing, Petroșani [4] Filip L., Dima N., 2014 Special mining surveying (in Romanian), Universitas Publishing, Petroșani [5] Vereș I., 2006 Automation of topo-geodetic works (in Romanian), Universitas Publishing, Petroșani

This article is an open access article distributed under the Creative Commons BY SA 4.0 license. Authors retain all copyrights and agree to the terms of the above-mentioned CC BY SA 4.0 license.

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590 vol. 28, issue 2 / 2022, pp. 54-62

METHODOLOGY FOR QUANTIFYING THE RISK OF OCCUPATIONAL ACCIDENT AND / OR DISEASE SPECIFIC TO COMPLEX TECHNICAL SYSTEMS Daniela FURDUI (PEAGU)1, Sorin Mihai RADU2* University of Petroșani, Petroșani, Romania Department of Mechanical, Industrial and Transports Engineering, University of Petroșani, Petroșani, Romania sorin_mihai_radu@yahoo.com 1

DOI: 10.2478/minrv-2022-0015 Abstract: This paper presents a scientific research in the field of the risk assessment, in order to secure the activities carried out in the presence of specific hazards of industrial work systems. The methodology for quantifying the risk of occupational is an innovative tool which highlights the analytical solution for quantify the occupational risks with impact, both on the human component, as well as at the level of the other component elements specific to the work systems. Keywords: accidents, industrial work systems, hazard, risk 1. Technical aspects specific the process of occurrence of the injury phenomenon The comprehensiveness of total risk makes the systemic assessment and management of risk tractable from many perspectives. The expected value of risk is an operation that essentially multiplies the consequences of each event by its probability of occurrence and sum (or integrates) all these products over the entire universe of events [1]. This operation literally commensurate adverse event of high consequences and low probabilities with events of low consequences and high probabilities. The mechanism of occurrence the working accident in the labour system is based on the work-specific risk generator and the time at which a certain lucrative activity takes place depending on the exposure to the risk factors. At any type of work activity there are risk factors associated to the potential hazards that can lead to accidents at work or occupational diseases. 2. Quantification of the global risk Mathematically, the values of the level of global risk (Nglobal risk ) can be calculated based on the rank of 𝑗=1,4 the risk factor (𝑟R𝑗=1,4 ) and the level of risk (R 𝑖=1,9 ̅̅̅̅00 ), as follows relation [2] (1): ̅̅̅̅𝑜𝑜 𝑖=1,9

N𝑔𝑙𝑜𝑏𝑎𝑙 𝑟𝑖𝑠𝑘 =

(𝑟R1

̅̅̅̅00 i=1,5

𝐑𝟏 ̅̅̅̅𝟎𝟎 )+(𝑟R2 𝐢=𝟏,𝟓 𝑟 R1

̅̅̅̅00 i=1,5

𝐑𝟐 ̅̅̅̅𝟎𝟎 )+(𝑟R3 𝐑𝟑 ̅̅̅̅𝟎𝟎 )+(𝑟R4 ̅̅̅̅00 𝐢=𝟏,𝟕 ̅̅̅̅00 ̅̅̅̅00 𝐢=𝟏,𝟗 i=1,8 i=1,7 i=1,9 𝑟 + 𝑟R2 + 𝑟 R3 4 R + ̅̅̅̅00 ̅̅̅̅00 ̅̅̅̅00 i=1,8 i=1,9 i=1,7

𝐑𝟒 ̅̅̅̅𝟎𝟎 ) 𝐢=𝟏,𝟖

(1)

- For risks generated by the work equipment available and the materials and substances used. These types of risks are generated by the endowment of the workplace in the basic location but also in other locations where the worker is occasionally or conjecturally:

Corresponding author: Radu Sorin Mihai, prof. Ph.D. eng., University of Petrosani, Petrosani, Romania, (University of Petrosani, 20 University Street, sorin_mihai_radu@yahoo.com) 54

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𝑟R1

̅̅̅̅00 i=1,5

𝐑𝟏𝐢=𝟏,𝟓 ̅̅̅̅𝟎𝟎

vol. 28, issue 2 / 2022 pp. 54-62 𝑟R100 1 𝑟R100 2 = 𝑟R1300 𝑥 𝑟R100 4 𝑟 R [ 100 ] 5

𝐑𝟏𝟏𝟎𝟎

1.00 𝐑𝟏𝟐𝟎𝟎 1.00 𝐑𝟏𝟑𝟎𝟎 = 1.00 𝑟𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟 𝑥 𝐑𝟏𝟑𝟎𝟎 1.00 𝐑𝟏𝟒𝟎𝟎 𝐑𝟏𝟒𝟎𝟎 [1.00] 𝟏 𝟏 [𝐑 𝟓𝟎𝟎 ] [𝐑 𝟓𝟎𝟎 ] 𝐑𝟏𝟐𝟎𝟎

where: [𝐑𝟏𝟏𝟎𝟎 ] = [𝐑𝟏Technical equipment ] [𝐑𝟏𝟐𝟎𝟎 ] = [𝐑𝟏Tools ] [𝐑𝟏𝟑𝟎𝟎 ] = = [𝐑𝟏Energy sources that put work equipment into operation,or from the place where the intervention is made or in the ] [𝐑𝟏𝟒𝟎𝟎 ] [𝐑𝟏𝟓𝟎𝟎 ]

= =

conjectural location 𝟏 [𝐑 Materials and substances used in the work process or in connection with the work process ] [𝐑𝟏Other risks generated ]

- For risks generated by the work environment in which the worker is in the work process: 𝐑𝟐𝟏𝟎𝟎 𝐑𝟐𝟏𝟎𝟎 𝑟R200 1.00 1 𝐑𝟐𝟐𝟎𝟎 𝐑𝟐𝟐𝟎𝟎 𝑟R200 1.00 2 𝐑𝟐𝟑𝟎𝟎 𝐑𝟐𝟑𝟎𝟎 𝑟R200 1.00 3 𝟐 𝟐 𝑟R2 00 𝐑𝟐𝐢=𝟏,𝟕 𝑥 𝐑 𝟒𝟎𝟎 = 1.00 𝑟𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟 𝑥 𝐑 𝟒𝟎𝟎 ̅̅̅̅𝟎𝟎 = 2 𝑟 R ̅̅̅̅ i=1,7 400 1.00 𝐑𝟐𝟓𝟎𝟎 𝐑𝟐𝟓𝟎𝟎 𝑟R200 0.33 5 𝐑𝟐̅̅̅̅̅̅̅̅̅̅̅ 𝐑𝟐̅̅̅̅̅̅̅̅̅̅̅ 𝑟 2 [1.00] 𝟎𝟏 ,𝟔𝟎𝟑 𝟔 𝟔𝟎𝟏 ,𝟔𝟎𝟑 01 03 [ R̅̅̅̅̅̅̅̅̅̅̅̅ ] 6 ,6 𝟐 𝟐 [ 𝐑 𝟕𝟎𝟎 ] [ 𝐑 𝟕𝟎𝟎 ] where: [𝐑𝟐𝟏𝟎𝟎 ] = [𝐑𝟐Generators related to weather conditions,temperature,brightness,air pressure,relative humidity ] [𝐑𝟐𝟐𝟎𝟎 ] = [𝐑𝟐Chemical agents ] [𝐑𝟐𝟑𝟎𝟎 ] = [𝐑𝟐Biological agents ] [𝐑𝟐𝟒𝟎𝟎 ] = [𝐑𝟐Dangerous animals and persons ] [𝐑𝟐𝟓𝟎𝟎 ] = [𝐑𝟐Dangerous meteorological situations,geological et.al. ] [𝐑𝟐𝟔𝟎𝟎 ] = [𝐑𝟐Hazardous situations generated by other jobs in the vicinity of the assessed job ] [𝐑𝟐𝟔𝟎𝟏 ] = [𝐑𝟐Noise ] [𝐑𝟐𝟔𝟎𝟏 ] = [𝐑𝟐Noise ] [𝐑𝟐𝟔𝟎𝟐 ] = [𝐑𝟐Vibrations ] [𝐑𝟐𝟔𝟎𝟑 ] = = [𝐑𝟐Risk−generating lucrative activities,carried out in jobs in the immediate vicinity of the assessed workplace or in the ] vicinity of the workplace where the intervention takes place or in the vicinity of the conjunctural place

[𝐑𝟐𝟕𝟎𝟎 ] = [𝐑𝟐other environmental situations ] - Risks generated by the employer and other factors responsible internally and externally to the employer who according to the law have certain obligations and responsibilities in the field of OSH [3]:

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

vol. 28, issue 2 / 2022 pp. 54-62 𝑟R300 1

𝑟R3̅̅̅̅̅̅̅̅̅̅̅̅ 201 ,204 R300 3 R3̅̅̅̅̅̅̅̅̅̅̅̅ 401 ,405

𝑟

𝑟 𝑟R3

̅̅̅̅00 i=1,9

𝐑𝟑𝟏𝟎𝟎 𝐑𝟑̅̅̅̅̅̅̅̅̅̅̅ 𝟐𝟎𝟏 ,𝟐𝟎𝟒 𝐑𝟑𝟑𝟎𝟎 𝐑𝟑̅̅̅̅̅̅̅̅̅̅̅ 𝟒𝟎𝟏 ,𝟒𝟎𝟓

𝑟R3̅̅̅̅̅̅̅̅̅̅̅̅ 𝑥 𝐑𝟑 𝐑𝟑𝐢=𝟏,𝟗 ̅̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅𝟎𝟎 = 501 ,503 𝟓𝟎𝟏 ,𝟓𝟎𝟑 𝑟R300 𝐑𝟑𝟔𝟎𝟎 6 𝑟R300 7 𝐑𝟑𝟕𝟎𝟎 𝑟R300 8 𝐑𝟑𝟖𝟎𝟎 𝑟R3̅̅̅̅̅̅̅̅̅̅̅̅ [ 901,904 ] 𝐑𝟑 ̅̅̅̅̅̅̅̅̅̅̅ 𝟗𝟎𝟏 ,𝟗𝟎𝟓

𝐑𝟑𝟏𝟎𝟎 𝐑𝟑̅̅̅̅̅̅̅̅̅̅̅ 𝟐𝟎𝟏 ,𝟐𝟎𝟒 1.00 0.25 𝐑𝟑𝟑𝟎𝟎 1.00 𝐑𝟑̅̅̅̅̅̅̅̅̅̅̅ 𝟒𝟎𝟏 ,𝟒𝟎𝟓 0.20 𝟑 = 1.00 𝑟𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟 𝑥 𝐑 ̅̅̅̅̅̅̅̅̅̅̅ 𝟓𝟎𝟏 ,𝟓𝟎𝟑 1.00 𝐑𝟑𝟔𝟎𝟎 1.00 𝐑𝟑𝟕𝟎𝟎 1.00 [0.25] 𝐑𝟑𝟖𝟎𝟎 𝐑𝟑̅̅̅̅̅̅̅̅̅̅̅ 𝟗𝟎𝟏 ,𝟗𝟎𝟓

where: [𝐑𝟑𝟏𝟎𝟎 ] = [𝐑𝟑Risks generated by the employer when framing with workers of the evaluated job ] [𝐑𝟑𝟐𝟎𝟎 ] = [𝐑𝟑Risks posed by persons responsible for training workers in the assessed job ] [𝐑𝟑𝟐𝟎𝟏 ] = [𝐑𝟑General introductory training ] [𝐑𝟑𝟐𝟎𝟐 ] = [𝐑𝟑On−the−job training ] [𝐑𝟑𝟐𝟎𝟑 ] = [𝐑𝟑Regular training ] [𝐑𝟑𝟐𝟎𝟒 ] = [𝐑𝟑Return−to−work training ] [𝐑𝟑𝟑𝟎𝟎 ] = = [𝐑𝟑Risks posed by persons who should ensure the proper functioning of the work equipment that is in the endowment of the ] assessed job,maintenance,repairs,service et.al.

[𝐑𝟑𝟒𝟎𝟎 ] = = [𝐑𝟑Risks posed by persons providing personal protective equipment (PPE) to workers at the assessed workplace ] [𝐑𝟑𝟒𝟎𝟏 ] = [𝐑𝟑Purchase of PPE ] [𝐑𝟑𝟒𝟎𝟐 ] = [𝐑𝟑PPE compliance ] [𝐑𝟑𝟒𝟎𝟑 ] = [𝐑𝟑If the purchased PPE provides protection against the assessed risks ] [𝐑𝟑𝟒𝟎𝟒 ] = [𝐑𝟑If the PPE has a service life correctly calculated ] [𝐑𝟑𝟒𝟎𝟓 ] = [𝐑𝟑If PPE is replaced whenever necessary ] [𝐑𝟑𝟓𝟎𝟎 ] = [𝐑𝟑Risks posed by persons who should monitor the health of workers ] [𝐑𝟑𝟓𝟎𝟏 ] = [𝐑𝟑Medical control at employment ] [𝐑𝟑𝟓𝟎𝟐 ] = [𝐑𝟑Periodic medical check−up ] [𝐑𝟑𝟓𝟎𝟑 ] = [𝐑𝟑Medical examination at the request of the worker ] [𝐑𝟑𝟔𝟎𝟎 ] == [𝐑𝟑Risks posed by people who should do special checks and do not do them at the assessed workplace ] [𝐑𝟑𝟕𝟎𝟎 ] = = [𝐑𝟑Risks posed by persons who should provide OSH signalling in the workplace whether or not they provide staff training ] [𝐑𝟑𝟖𝟎𝟎 ] = [𝐑𝟐Risks posed by people who should provide first aid at the assessed workplace ] [𝐑𝟑𝟗𝟎𝟎 ] = [𝐑𝟑Risks posed by job leaders for the assessed job ] [𝐑𝟑𝟗𝟎𝟏 ] = [𝐑𝟑If they are or not professionally trained ] [𝐑𝟑𝟗𝟎𝟐 ] = [𝐑𝟑If the selection is made on the principle of competence ] [𝐑𝟑𝟗𝟎𝟑 ] = [𝐑𝟑If they know how to formulate,transmit work tasks and control how they are accomplished ] [𝐑𝟑𝟗𝟎𝟒 ] = [𝐑𝟑If they know how to properly manage the situations at the evaluated workplace ]

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

vol. 28, issue 2 / 2022 pp. 54-62

- Risks generated by the employee:

𝑟

R4i=1,8 ̅̅̅̅00

𝐑𝟒𝐢=𝟏,𝟖 ̅̅̅̅𝟎𝟎

𝑟R400 1 𝑟R400 2 𝑟R400 3 𝑟R400 = 𝑟 44 𝑥 R500 𝑟R400 6 𝑟R400 7 𝑟 R [ 400 ] 8

𝐑𝟒𝟏𝟎𝟎 𝐑𝟒𝟐𝟎𝟎 𝐑𝟒𝟑𝟎𝟎 𝐑𝟒𝟒𝟎𝟎 𝐑𝟒𝟓𝟎𝟎 𝐑𝟒𝟔𝟎𝟎 𝐑𝟒𝟕𝟎𝟎

𝐑𝟒𝟏𝟎𝟎 1.00 1.00 1.00 1.00 = 𝑟 𝑥 1.00 𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟 1.00 1.00 [1.00]

𝐑𝟒𝟖𝟎𝟎

𝐑𝟒𝟐𝟎𝟎 𝐑𝟒𝟑𝟎𝟎 𝐑𝟒𝟒𝟎𝟎 𝐑𝟒𝟓𝟎𝟎 𝐑𝟒𝟔𝟎𝟎 𝐑𝟒𝟕𝟎𝟎 𝐑𝟒𝟖𝟎𝟎

where: [𝐑𝟒𝟏𝟎𝟎 ] = [𝐑𝟒If he knows the hierarchical structure − direct bosses and the immediate bosses ] [𝐑𝟒𝟐𝟎𝟎 ] = [𝐑𝟒If he knows the significance of the existing signs and signals at the workplace ] [𝐑𝟒𝟑𝟎𝟎 ] = [𝐑𝟒If he knows how to use,maintenance and replacement of PPE ] [𝐑𝟒𝟒𝟎𝟎 ] = [𝐑𝟒If he knows how to remedy any non−conformities that may occur at work ] [𝐑𝟒𝟓𝟎𝟎 ] = [𝐑𝟒If there are working procedures available to the worker and if he knows them ] [𝐑𝟒𝟔𝟎𝟎 ] = = [𝐑𝟒If the workers in the evaluated job have physical,mental,moral,intellectual,professional qualities corresponding to the ] evaluated job 𝟒 = [𝐑 𝟕𝟎𝟎 ] = [𝐑𝟒If the workers in the assessed job have had disciplinary offenses,occupational diseases,accidents at work or incidents ] [𝐑𝟒𝟖𝟎𝟎 ] = [𝐑𝟒Other risks generated by the executor in the work process ]

Starting from the risks listed above, we define the domains of definition of the risk function R, as follows: 3 2 4 R = f(R1i=1,5 ̅̅̅̅00 , R i=1,7 ̅̅̅̅00 , R i=1,9 ̅̅̅̅00 , R i=1,8 ̅̅̅̅00 ),

(2) ̅̅̅̅̅̅̅

𝑚=I,VIII In the case of a normal 8-hour work schedule, the values of the risk factor correction coefficient (𝑘𝑖=1,9 ) ̅̅̅̅ ̅̅̅̅̅̅̅ depending on the exposure for different scenarios (𝑚 = I, VIII) are shown in Table 1:

Time (h) Scenario m Exposure (h)

1 (h)

2 (h)

3 (h)

Table 1 4 (h)

5 (h)

6 (h)

7 (h)

8 (h)

III

VII

VIII

1.3x10-1

2.5x10-1

3.8x10-1

5.0x10-1

6.3x10-1

7.5x10-1

8.8x10-1

10.0x10-1

If we take into account the quantitative ratio that exists at group and subgroup level, transforming the weighting result into a scaled value that constitutes the momentary value of the range of values corresponding to the rank of the risk factor, results the following mathematical relation [4, 5]: - For risks generated by the work equipment available and the materials and substances used, according to the Table1 (𝑚 = ̅̅̅̅̅̅ I, VIII):

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

vol. 28, issue 2 / 2022 pp. 54-62 𝑟 𝑚 R100 1

𝐑𝟏𝟏𝟎𝟎

𝐑𝟏𝟐𝟎𝟎

𝑟 𝑚 R100 𝑟 𝑚 R1

̅̅̅̅00 i=1,5

̅̅̅̅̅̅̅ 𝑟 𝑚 R100 𝑥 𝐑𝟏 𝟎𝟎 = [𝑘 𝑚=I,VIII 𝐑𝟏𝐢=𝟏,𝟓 ] 𝑟𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟 𝑥 𝐑𝟏𝟑𝟎𝟎 ̅̅̅̅𝟎𝟎 = ̅̅̅̅ 𝑖=1,5 𝟑 3 𝑟 𝑚 R100 𝐑𝟏𝟒𝟎𝟎 𝐑𝟏𝟒𝟎𝟎 4

𝑚 𝟏 [𝑟 R1500 ] [𝐑 𝟓𝟎𝟎 ]

𝟏

[𝐑 𝟓𝟎𝟎 ]

I 𝑘𝑖=1,5 ̅̅̅̅ II 𝑘𝑖=1,5 ̅̅̅̅ III 𝑘𝑖=1,5 ̅̅̅̅ ̅̅̅̅̅̅̅ 𝑚=I,VIII [𝑘𝑖=1,5 ] ̅̅̅̅

IV 𝑘𝑖=1,5 ̅̅̅̅ V 𝑘𝑖=1,5 ̅̅̅̅ VI 𝑘𝑖=1,5 ̅̅̅̅ VII 𝑘𝑖=1,5 ̅̅̅̅

1.3x10−1 2.5x10−1 3.8x10−1 −1 = 5.0x10−1 6.3x10 7.5x10−1 8.8x10−1 [10.0x10−1 ]

VIII ̅̅̅̅ ] [𝑘𝑖=1,5

For risks generated by the work environment in which the worker is in the work process, according to the Table 1 (𝑚 = ̅̅̅̅̅̅̅ I, VIII): 𝑟 𝑚 R200 1

𝐑𝟐𝟏𝟎𝟎

𝐑𝟐𝟐𝟎𝟎

𝑟 𝑚 R200

𝐑𝟐𝟑𝟎𝟎

𝑟 𝑚 R200

𝐑𝟐𝟒𝟎𝟎

𝑟 𝑚 R200 3

𝑟 𝑚 R2

̅̅̅̅00 i=1,7

̅̅̅̅̅̅̅

𝑚=I,VIII 𝟐 𝑚 𝐑𝟐𝐢=𝟏,𝟕 ] 𝑟𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟 𝑥 𝐑𝟐𝟓𝟎𝟎 ̅̅̅̅𝟎𝟎 = 𝑟 R200 𝑥 𝐑 𝟓𝟎𝟎 = [𝑘𝑖=1,7 ̅̅̅̅ 5 𝐑𝟐𝟔𝟎𝟏 𝐑𝟐𝟔𝟎𝟏 𝑟𝑚 2 R601

𝑟R202 6 𝑟R203 6 𝑟 R [ 2700 ]

𝐑𝟐𝟔𝟎𝟐

𝐑𝟐𝟔𝟎𝟑

𝐑𝟐𝟕𝟎𝟎

I 𝑘𝑖=1,5 ̅̅̅̅,7 II 𝑘𝑖=1,5 ̅̅̅̅,7 III 𝑘𝑖=1,5 ̅̅̅̅,7 ̅̅̅̅̅̅̅

𝑚=I,VIII [𝑘𝑖=1,7 ]= ̅̅̅̅

IV 𝑘𝑖=1,5 ̅̅̅̅,7 V 𝑘𝑖=1,5 ̅̅̅̅,7 VI 𝑘𝑖=1,5 ̅̅̅̅,7 VII 𝑘𝑖=1,5 ̅̅̅̅,7

1.3x10−1 4.125x10−2 2.5x10−1 8.250x10−2 −1 3.8x10 12.375x10−2 −1 ̅̅̅̅̅̅̅ 𝑚=I,VIII 16.500x10−2 = 5.0x10−1 , [𝑘𝑖=6 01 ,603 ] = ̅̅̅̅̅̅̅̅̅̅ 6.3x10 20.625x10−2 −1 7.5x10 24.750x10−2 8.8x10−1 28.875x10−2 [10.0x10−1 ] [33.000x10−2 ]

VIII ̅̅̅̅,7 ] [𝑘𝑖=1,5

- For risks generated by the employer and other factors responsible internally and externally to the employer who according to the law have certain obligations and responsibilities in the field of OSH, according to the Table 1 (𝑚 = ̅̅̅̅̅̅̅ I, VIII):

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

vol. 28, issue 2 / 2022 pp. 54-62 𝑟 𝑚 R300 1

𝐑𝟑𝟏𝟎𝟎

𝐑𝟑𝟐𝟎𝟏

𝐑𝟑𝟐𝟎𝟐

𝐑𝟑𝟐𝟎𝟑

𝐑𝟑𝟐𝟎𝟒

𝐑𝟑𝟑𝟎𝟎

𝑟 𝑚 R301

𝐑𝟑𝟒𝟎𝟏

𝑟 𝑚 R302

𝐑𝟑𝟒𝟎𝟐

𝐑𝟑𝟒𝟎𝟑

𝑟 𝑚 R301 2

𝑟 𝑚 R302 2

𝑟 𝑚 R303 2

𝑟 𝑚 R304 2

𝑟 𝑚 R300 3 4 4

𝑟 𝑚 R303

𝑟 𝑚 R3

̅̅̅̅00 i=1,9

̅̅̅̅̅̅̅

𝑚=I,VIII 𝑚 𝐑𝟑𝐢=𝟏,𝟗 𝑥 𝐑𝟑𝟒𝟎𝟒 = [𝑘𝑖=1,9 ] 𝑟𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟 𝑥 𝐑𝟑𝟒𝟎𝟒 ̅̅̅̅𝟎𝟎 = 𝑟 R3 ̅̅̅̅ 04 4 𝐑𝟑𝟒𝟎𝟓 𝐑𝟑𝟒𝟎𝟓 𝑟𝑚 3 R 05 4 𝑚 3 𝑟 R 00 5 𝑟 𝑚 R300 6 𝑟 𝑚 R300 7 𝑟 𝑚 R300 8 𝑟 𝑚 R301 9 𝑟 𝑚 R302 9 𝑟 𝑚 R303 9 𝑚 3 𝑟 [ R 04 9

𝐑𝟑𝟓𝟎𝟎

𝐑𝟑𝟔𝟎𝟎

𝐑𝟑𝟕𝟎𝟎

𝐑𝟑𝟖𝟎𝟎

𝐑𝟑𝟗𝟎𝟏

𝐑𝟑𝟗𝟎𝟐

𝐑𝟑𝟗𝟎𝟑

𝐑𝟑𝟗𝟎𝟒

] I 𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904

I 𝑘𝑖=1,3,5,8 ̅̅̅̅ II 𝑘𝑖=1,3,5,8 ̅̅̅̅ III 𝑘𝑖=1,3,5,8 ̅̅̅̅

̅̅̅̅̅ 𝑚=I,VIII [𝑘𝑖=1,3,5,8 ̅̅̅̅ ]

IV 𝑘𝑖=1,3,5,8 ̅̅̅̅ V 𝑘𝑖=1,3,5,8 ̅̅̅̅ VI 𝑘𝑖=1,3,5,8 ̅̅̅̅ VII 𝑘𝑖=1,3,5,8 ̅̅̅̅

1.3x10−1 2.5x10−1 3.8x10−1 ̅̅̅̅̅ 5.0x10−1 𝑚=I,VIII ,[𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904 ] −1 6.3x10 7.5x10−1 8.8x10−1 [10.0x10−1 ]

VIII

[𝑘𝑖=1,3,5,8 ̅̅̅̅ ]

II 𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904 III 𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904

IV 𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904 V 𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904 VI 𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904 VII 𝑘𝑖=2 ̅̅̅̅̅̅̅̅̅̅ ̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904 VIII

̅̅̅̅̅̅̅̅̅̅ 01 ,204 ,9 01 ,904 ] [𝑘𝑖=2̅̅̅̅̅̅̅̅̅̅ I 𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05 II 𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05 III 𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05

̅̅̅̅̅ 𝑚=I,VIII [𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05 ]

IV 𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05 V 𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05 VI 𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05 VII 𝑘𝑖=4 ̅̅̅̅̅̅̅̅̅̅̅ 01 ,4 05 VIII

01 ,4 05 ] [𝑘𝑖=4̅̅̅̅̅̅̅̅̅̅̅

2.500x10−2 5.000x10−2 7.500x10−2 10.000x10−2 12.500x10−2 15.000x10−2 17.500x10−2 [20.000x10−2 ]

3.125x10−2 6.250x10−2 9.375x10−2 12.500x10−2 , 15.625x10−2 18.750x10−2 21.875x10−2 [25.000x10−2 ]

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

vol. 28, issue 2 / 2022 pp. 54-62

For risks generated by the employee: 𝑟 𝑚 R400 1

𝑟 𝑚 R4 00 ̅̅̅̅ i=1,8

𝐑𝟒𝐢=𝟏,𝟖 ̅̅̅̅𝟎𝟎

𝑟 𝑚 R400 2 𝑟 𝑚 R400 3 𝑟 𝑚 R400 4 𝑟 𝑚 R400 5 𝑟 𝑚 R400 6 𝑚 4 𝑟 R 00 7 𝑚 4 [𝑟 R 00 8

𝑥

]

𝐑𝟒𝟏𝟎𝟎

𝐑𝟒𝟐𝟎𝟎

𝐑𝟒𝟑𝟎𝟎

𝐑𝟒𝟒𝟎𝟎 𝐑𝟒𝟓𝟎𝟎

̅̅̅̅̅ 𝑚=I,VIII [𝑘𝑖=1,8 ̅̅̅̅ ]𝑟𝑟𝑖𝑠𝑘 𝑓𝑎𝑐𝑡𝑜𝑟

𝑥

𝐑𝟒𝟒𝟎𝟎 𝐑𝟒𝟓𝟎𝟎

𝐑𝟒𝟔𝟎𝟎

𝐑𝟒𝟕𝟎𝟎

𝐑𝟒𝟖𝟎𝟎

I 𝑘𝑖=1,8 ̅̅̅̅ II 𝑘𝑖=1,8 ̅̅̅̅ III 𝑘𝑖=1,8 ̅̅̅̅

𝑚=̅̅̅̅̅ I,VIII [𝑘𝑖=1,8 ̅̅̅̅ ]

IV 𝑘𝑖=1,8 ̅̅̅̅

V 𝑘𝑖=1,8 ̅̅̅̅ VI 𝑘𝑖=1,8 ̅̅̅̅ VII 𝑘𝑖=1,8 ̅̅̅̅ VIII

1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 [10.0x10−1 ]

[𝑘𝑖=1,8 ̅̅̅̅ ] In the case of a total or partial exposure, we obtain the results that obtained by used the above mathematical relations and Table 2.

Group of risks

R1i=100 R1i=200 𝐑𝟏𝐢=𝟏,𝟓 ̅̅̅̅𝟎𝟎

R1i=300 R1i=400 R1i=500

𝐑𝟐𝐢=𝟏,𝟔 ̅̅̅̅𝟎𝟎

Table 2 The fact of multiplying the rank of the risk factor, The fact of multiplying the associated with the risk rank of the risk factor, group according to the associated with the risk hourly exposure subgroup Risk subgroup The value The value of the Exposure time Exposure of the multiplication m=I÷VIII time multiplication fact m=I÷VIII fact 1.00 1.3x10−1 1.00 2.5x10−1 1.00 3.8x10−1 1.00 5.0x10−1 1.00 6.3x10−1 1.00 7.5x10−1 1.00 8.8x10−1 1.00 10.0x10−1

Rank value based on exposure ̅̅̅̅̅

𝑚=I,VIII 𝑘𝑖=1,9 ̅̅̅̅

1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 10.0x10−1

R2i=100

1.00

1.3x10−1

R2i=200

1.00

2.5x10−1

1.00

3.8x10−1

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

vol. 28, issue 2 / 2022 pp. 54-62

R2i=300

1.00

5.0x10−1

R2i=400

1.00

6.3x10−1

1.00

7.5x10−1

1.00

8.8x10−1

1.00

10.0x10−1

R2i=500 R2i=700

R2i=601 R2i=602 R2i=603

R2i=600

𝐑𝟑𝐢=𝟏,𝟗 ̅̅̅̅𝟎𝟎

R3i=100 R3i=300 R3i=500 R3i=600 R3i=700 R3i=800

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

0.33

R3i=201 R3i=202 R3i=203 R3i=204

R3i=401 R3i=402 R3i=403 R3i=404 R3i=405

R3i=400

0.25

0,20

R3i=901 R3i=902

R3i=900

R3i=903 R3i=904

R4i=100 R4i=300 R4i=500 R4i=600 R4i=700 R4i=800

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 10.0x10−1 1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 10.0x10−1 1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1

4.125x10−2 8.250x10−2 12.375x10−2 16.500x10−2 20.625x10−2 24.750x10−2 28.875x10−2 33.000x10−2 1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 10.0x10−1 3.125x10−2 6.250x10−2 9.375x10−2 12.500x10−2 15.625x10−2 18.750x10−2 21.875x10−2 25.000x10−2 2.500x10−2 5.000x10−2 7.500x10−2 10.000x10−2 12.500x10−2 15.000x10−2 17.500x10−2 20.000x10−2 3.125x10−2 6.250x10−2 9.375x10−2 12.500x10−2 15.625x10−2 18.750x10−2 21.875x10−2

10.0x10−1

25.000x10−2

1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 10.0x10−1

R3i=200

𝐑𝟒𝐢=𝟏,𝟖 ̅̅̅̅𝟎𝟎

1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 10.0x10−1

0.25

1.3x10−1 2.5x10−1 3.8x10−1 5.0x10−1 6.3x10−1 7.5x10−1 8.8x10−1 10.0x10−1

Revista Minelor – Mining Revue ISSN-L 1220-2053 / ISSN 2247-8590

vol. 28, issue 2 / 2022 pp. 54-62

3. Interpretation of the results obtained This methodological tool for quantifying risk parameters has been developed for risk estimation and assessment, in order to diagnose and predict the probabilities of the injurie phenomenon that can manifest itself at the level of a complex work system. For the purpose of this paper, risk is defined as a measure of the probability and severity of harm (adverse effects) because measuring risk is an empirical, quantitative, scientific activity. The premise that risk assessment must be an integral part of the overall decision-making process necessitates following a systemic, holistic approach to dealing with risk. Such a holistic approach builds on the principals and philosophy upon which system analysis and safety system engineering are grounded. Applying this method, for the same type of different activity evaluated, at the same time, for the same work point, many evaluators, independent of each other, finally obtain approximate equal results. At the same time, the method is flexible, allowing its adaptation to any work system with activity in the normal or potential explosive environment and to any organizational structure where the human component is analysed in the work process. 4. Conclusions For determining the risk, this methodical tool is a modern technique used to identify and assess occupational risk factors for quantifying the risk indicators was developed, in order to make the diagnosis and the plausible forecast of the mechanism of occurrence of an undesirable event. This method is flexible allowing its adaptation to any work system for different types of activities for which specific risk categories and subcategories and to any organizational structure where the human component is analysed in the work process. References [1] Gabor D.S., Radu S.M., 2021 An innovative method for testing electronic detonating caps regarding sensitivity to electrostatic discharges, Mining Revue, Vol. 27, Nr. 1/2021, pp. 61-65, ISSN-L 1220-2053 / ISSN 2247-8590 [2] Marhavilas K., 2008 A risk-estimation methodological framework using quantitative assessment techniques and real accidents' data: Application in an aluminum extrusion industry, Journal of loss prevention in the process industries, 21, 596 – 603, 2008. [3] Pece, Şt., 2010 Risk assessment in the workplace, Rubin Publishing House, Galaţi, Romania [4] Vasilescu G.D., 2008 Probability calculation methods used for industrial risk diagnose and prediction (in Romanian), INSEMEX Publishing, Petrosani, Romania, ISBN 978-973-88753-2-6. [5] Vasilescu G.D., 2008 Unconventional methods for the professional risk analysis and evaluation (in Romanian), INSEMEX Publishing, Petrosani, Romania, ISBN 978-973-88590-0-5.

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