CONTENTS
Gheorghe MANOLEA Capitalization the creativity potential of universities by innovation and technology transfer
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Dumitru FODOR, Petre DIACONESCU Evolution of lignite exploitation in the coal pits of Rovinari coal basin
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Svetlana BRATKOVA, Anatoliy ANGELOV, Alexandre LOUKANOV, Katerina NIKOLOVA, Sotir PLOCHEV, Rosen IVANOV Biotechnological removal of heavy metals from mining wastewaters by dissimilative sulphate reduction
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Cristina IONIC , Victor ARAD The stability of the heap branch II Coroie ti - E.P.C.V.J. Vulcan
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Ecaterina BALANEANU, Victor ARAD, Leti ia Susana ARAD, Flavius BALANEANU Preparation and development of geotechnical map of Alba Iulia town, Alba district
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Roland Iosif MORARU, Gabriel Bujor B BU A contextual analysis of occupational accidents occurred in Valea Jiului collieries during the last four decades
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CAPITALIZATION THE CREATIVITY POTENTIAL OF UNIVERSITIES BY INNOVATION AND TECHNOLOGY TRANSFER Gheorghe MANOLEA*
Abstract The paper presents the results of an experience based on the management inside the team, which combines the intellectual power and the emotional impact, specific to the innovative and creative activity, and which can be a response to the problems with which the academic technical education and the research face nowadays: the candidates and students’ lack of motivation while in an acute need of rehabilitation/rejuvenation and automation of industrial activities; the decrease of the competitiveness of the Romanian institutes of research; the necessity to transform the universities into entrepreneurial units where the share of extra-budgetary financing increases proportionately to the financing from the state budget; the lack of legal and organizing frame within which the students could acquire and practice creative-innovative and applicative-practical skills. Keywords: innovation, technological transfer, university 1. Innovation. Technology transfer Innovation has almost the same definition in all specialized literature [1],[16] as being an activity of improving a product in order to be applied in industrial activity which comprises its design, its production, its experiment and its market launch. As a result, innovation, in comparison with
invention, does not represent absolute news, but its application and speed implementation are more accessible. Within engineering society from Romania, invention has had a privileged status compared with innovation, fact which stimulated the setting up the group of the „patent collectors”, thinking that the number of the patents is more important than the number of the applications of an invention. At the same time, in universities it is unanimously accepted the idea that scientific papers are valuable even if they avoid, through number stimulation or direct evasion, confront with practice, application or applicability. These two mentalities are not useful for the creator and for the social life. It can be said that the definition, the demonstration of a solution opens the way towards progress, and its application, namely the innovation, carries the society towards progress. By these associations we can justify the saying “innovation is a way of capitalization the academic research”. Taking into account the experience accumulated during years, we defined innovation as an architecture (figure 1) based on: - a idea, a concept, a scientific procedure; - a qualified industrial partnership; - a network of national and/or international capitalization; - a powerful extended protection of industrial property.
Technology Transfer Centers
Industry
Search Necessity
Fundamental research, interdisciplinary, applied
University
Innovation
Technology Transfer
Science parcs
Fig.1 Explanation regarding innovation concept _____________________________ * Prof.eng.Ph.D University of Craiova
Trader Companies
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2. Citt Craiova – my example or case study The Centre of Innovation and Technology Transfer was set up in 1992 [15] as a unit of Ministry of Education and Science, and nowadays it functions as a Research Department within University of Craiova [14]. Its initial purposes [2],[3] have permanently been completed and adapted [4],[5] so that they can be fulfilled [6]. Currently, the purposes of the centre are: - capitalization of research results and technology transfer from research and development units to interested companies together with necessary technical assistance and service; - fund management form different sources in order to sustain the innovation and technology transfer projects; - organization and participation to local, national and international activities which stimulate innovation and technology transfer;
- stimulation of new technological companies which are organized or led by graduates, especially from University of Craiova; - representation and market launch strategy for new products and technologies, drawing marketing policies and strategies; 3. Management of human resources Management of human resources [7],[8],[10] was adapted to current economic conditions, in which the research project subjects have had a spectacular development. This phenomenon needs to convince the best specialists to join the existed research teams, taking into account, at the same time, the fact that all of them cannot be maintained in these teams for a long time because: - they are wanted in other research teams; - they can not perform at their maximum professional capacity; sometimes their specialization is overshadowed; This is why the human resources has two components (fig.2): full-time employees and collaborators (professors, Ph.D. students, specialists, students). For each category we can enumerate the arguments for their collaboration and their selection criteria, but, in this paper, we will insist on full-time employees.
PERMANENT
SELECTION FORMATION SEPARATION TEACHERS
COLLABORATORS
Technology transfer is regarded either as a subprocess of innovation or as a stage which follows it in order to complete the architecture of innovation concept. Within the context of capitalizing the research results, the technology transfer can be achieved as: - a transfer between two research activities – from fundamental research to applicative science; - a transfer between applicative research and industrial application; - a transfer from creative-innovative activities carried out by individuals (Ph.D. students, inventors, creators) to applicative activity (we have to mention that sometimes it is necessary to have an intermediate stage of applicative research or technological adaptation). It results that units, organizations in charged with technology transfer are an interface among interested social groups: the bidders of research results and the potential beneficiaries. Based on our experience, we can state that for the Romanian academic conditions there is possible for centers of innovation and technology transfer to function because they are directly connected with research and they can easily set up intermediate contracts, of interface. The object of technology transfer is made up by the research, innovation and development activities for which it was signed an intellectual property document and which is made up of knowledge, products, procedures, methods, technologies, execution documents, computer programs, data bases. The results or/and the intellectual property documents can be transferred. [16]
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Romanian Students Foreign Students Industry specialists with higher education Technical, Economic, Administrative and other Specialized
Fig.2 Human resource management, general assembly In the first place, the existence of these categories is absolutely necessary in order to form an organizational culture, otherwise this culture will be naturally imposed or borrowed from the university the centre and research department functions in.
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The strategy for selecting the full-time employees (fig.3) is based on several value criteria, following their performances, collectivity spirit, motivation capacity for innovative research oriented toward application and technology transfer. The target group is formed of students from technical faculties, but also from science faculties. Step I IDENTIFICATION
Step II SELECTION
It is recommended that these students should be supervised before being employed during several types of activities (professional, social, associated) over 1-2 years, and the best of them should be selected, the ones who are motivated and who are capable to integrate themselves within an already formed research team. Their capacity should be previously checked during common activities. Step IV
Step III FORMATION
Inovation Technology Transfer
Students
Year IV
The doctoral training
Tehnical Colleges
Scientific events
Visit to documentation
Year V
Teaching activity
Detachment
Fig.3 Strategy to select and form full-time employees 4. Management of research projects The research activity is organized in such a way that every research project should comply with the following stages: - market study regarding the product necessity; - identification of a potential manufacturer and of a potential distribution of the product; - research; - design; - manufacture of the prototype; - experiments; - technology transfer. We also consider that centers of Innovation and Technology Transfer which functions together with a university should select research themes taking into account the following characteristics: - they use latest technologies; - innovation- transfer cycle is short; - for use there are not necessary huge investments or the production conditions already exists; - resulted products are largely required on the market; - they have a strong social impact; - they can be used also in complementary fields apart from the basic one. Within this context the strategy of the themes of B.A. diplomas, of M.A. diplomas and Ph.D. thesis should take into account the following initial sources: - the research contracts of the Centre;
- the Ph.D. thesis written or supervised by the professors; - internal researches of the departments which can represent a starting point for a future research project; - requests from companies when signed professional contracts between professors and representatives of these companies. 5. Link to the socio-economic environment The University is permanently present in educational, social, economic and cultural life. Its activities must be permanently adapted to the environment which also changes all the time and which considers “excellence” to be a priority. Nowadays, when the market is regulated by demand and offer, the University makes available its values to the economic environment, helping the field of contractual research and continuous training. The offer of university belongs to the fields of fundamental research –institutional base, applicative research, services for society. In Europe the link between a university and social-economic environment is made up through an interface which holds several names – Link Office with Industry, Companies-University Interface, Centre for Technology Transfer. This interface allows companies to take advantage of the human and technical resources which is concentrated in university and to adapt the
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- searching the opportunities of collaboration with socio-economic environment, promoting companies with universities, promoting the equipment in universities and the academic services in industrial field.
Prototype ACVAR First appl ication
6.1 Frequency and power static converter for ACVAR variable speed electro-mechanical drives This example (fig.4) illustrates both the application of human resources strategy and the innovation: applicative research, patenting the product, transfer to SC AS INTERNATIONAL SRL. It is emphasized the fact that technology transfer is also concerned here with the human resources delivered by CITT.
Modernization - ACVAR Promotion Eng. Cerban Gabriel
Modernization - ACVAR Promotion
Transfer
Technology
Transfer
Technology
EXPANSION AS INTERNATIONAL
Transfer
Technology
Transfer
Technology
Technology
Eng. V duva Alexandru
6. Results of CITT regarding innovation and technology transfer
DEVELOPMENT AS INTERNATIONAL
Transfer
Student CRIVINEANU DO RU
AS INTERNATIONAL
academic research results. It facilitates: capitalization of researches in economy, continuous training, promotion of researches, identification of research projects, professional assistance in research field. The advantage of an university consists of interdisciplinarity based on an exchange system in which every part does its best. Within local development and world growth, an university represents a guarantee for success for all companies that ask for its help. The roles of the interface are: - identification of companies’ necessities: filed study and data analysis which can allow a correct interpretation of the collaboration between University and Small and Medium-Sized Companies; - transfer of academic excellence: it can accomplished by technology transfer, industrial projects design, patent use, etc;
Modernization - ACVAR Promotion
Eng. Doroban u Elian
Student
IN NOVATION and TE CHNOLOGY TRANSFER CENTER 1991 - 1993
1994 - 1996
1997 - 2000
2000 - 2003
Fig.4 History of ACVAR 6.2 Heating System with elements having SIR DUNA 2000 positive temperature coefficient This example illustrates the way in which the products that use high technologies were selected and the possibilities of use them in more fields.
Fig. 5 Static characteristics of heating element
The application was started with a heating unit which uses an element with a positive temperature coefficient. The electric power obtained (up to 2000 W) depends on the air flow that goes through it (figure 5). In order to regulate the flow it is used a micro motor (50W) which is supplied by an AC variator. Initially, the heating unit, called DUNA 2000, was developed for home appliances, but the big success was represented by warming up storage rooms for food products. For this application [9] it was used a system with a microcontroller (figure 6) in order to measure the temperature in several points of the storage room and to regulate the dissipated power by every heating unit according to the zone in which it was placed [11]. Presently, the product is used for heating the cabin of electric locomotives modernized by several Small and Medium-Sized companies from Craiova and for heating the spaces where Pleurotus mushrooms are planted [12 ],[13].
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6.3 Programmable PROCOMAND automaton Starting from the conclusion that the Romanian industry needs retechnologization, modernization in automatizations, it was created a basic system with a microcontroller MICRON [3] which was used in several applications (figure 7), one of them for SIR DUNA 2000 system. The advantage is determined by the fact that the hardware is accompanied by software that assures capitalization of creativity potential of professors and students. One of the applications, the teaching variant called PROCOMANDID, is used with students during lab classes from the Faculty of Electrical Engineering from University of Craiova.
Temp. sensor
Fig. 6 The structure of SIR DUNA 2000 heating system MICROAS Command automatically lifts food
CROBIL System for counting time use of billiard tables
PROCOMANDID Teaching PLC
CROMON Time monitoring of machine tools
PROCOMAND - PAN Comand line wafer
PROCOMAND - PROMAT Engine test stand equipment
ICMET Scales - tackle - pallet trucks - vehicles
PROCOMAND - PLC
Fig. 7 Applications PROCOMANDID automaton 6.4 Monitoring System for testing rubber products – MONIPRES This example illustrates very well the concept of innovation that can be defined as an activity of improving, of modernization of a product. SC RONERA from Pitesti is a company specialized in building composite subassemblies - metal, rubber. The external beneficiaries requested the supply of
Fig.8.Unmodernized press
some electronic bulletins. RONERA has several presses which registered the diagram F=f(s) with a pen on paper (figure 8). The modernization proposed by CITT was represented by a purchase system (figure 9) based on the programmable automaton MICRON and on a software that analysis the information obtained during the test (figure 10).
Fig.9.Modernized press
The same solution was applied in 2012 at ARTEGO Tirgu-Jiu.
Fig.10 Stretching - force diagram
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6.5.System for monitoring the launching units of anti-hail rockets This example illustrates the strategy of elaborating the subjects of B.A. diplomas, of M.A. diplomas and of Ph.D. theses and the strategy of industrial property protection with the help of patents and the internationalization of researches. The National Anti-Hail System was set up in Romania in 1999. This type of system functions in two neighbouring countries for more than 40 years: The Republic of Moldavia and Bulgaria. Based on the collaboration with the Technical University of Moldavia, it has been developed a monitoring system of transferring the energy from the photovoltaic panels to power elements and to consumers so that some functional conditions should be fulfilled (fig. 11). The subject was developed by Laurentiu Alboteanu, professor at Faculty of Electrical Enginnering, in his M.A. diploma, his Ph.D. thesis and during a post-doctoral research. For the solution he proposed he was awarded the Invention Patent.
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ramp of rockets which will have a different concept and which will be used in Romania, Republic of Romania and Bulgaria.
Fig.12. Manually positioned ramp 6.6. Example regarding technological animation Technological animation done by a university supposes a permanent research of the opportunities which led to the better relationship between social and economic environment and university; it also supposes the promotion of companies within academic environment and of academic idea within industrial environment. An example of this promotion is represented by the relationship between CITT Craiova and Cummins Generators Technologies Ltd. The collaboration started by carrying out some tests regarding the heating of the connections between the windings of the generator and connecting cables with the exterior (fig.13)
Fig.11 Energetic system of launching units of anti-hail rockets
This example also illustrates the approach of some research themes with a strong social impact. Taking into account the fact that the National AntiHail system in Romania is developing, the researches have continued with two Ph.D. theses. One, which will be submitted this year, belongs to Constantin Dulea who proposes a complex integrated system to monitor the important information regarding the fight against hail. For the proposed solution it was applied for an Invention Patent A00452/20.06.2012. the second thesis, started in 2011 by professor Stefan-Marian Nicolae, who graduated the Faculty of Automation and Computers from Craiova, discusses the automatic positioning of the launching ramp of anti-hail rockets (figure 12), and the solution is part of the integrated system for which it was requested an invention patent. The analyzed theme is also the subject of a cross-border project between Romania and Bulgaria during 2011-2014. Among the products that will be modernized within this project is also the launching
Fig.13. The exemplification of the connections and their thermal values Afterwards, the collaboration consisted of teaching some 8-hour courses by professors from Faculty of Electrical Engineering. After these courses, there were signed some contracts which
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follow the steps described in figure 1: fundamental research, the application of the solution to the beneficiary. This can be also exemplified with the heating of the connections. There were produced models which were analyzed mathematically and by numeric stimulation. The best technological
Fig. 14 After visiting Cummins
7. Conclusions We consider that the accumulated experience in over twenty years of activity carried out in the above presented context justifies the setting up of a dialogue regarding technology transfer, capitalization of academic research results, link between university and socio-economic field. We have to emphasize that this experience should be considered a model which can be extended, adapted, but not neglected. References 1. Ciotea, Fl., Ple a, O., Naum, N. The Innovation and Change Defiance, Editura MULTIMEDIA, Târgu Mure , (1996). 2. Manolea, Gh., B l nescu, S. The management particularities of innovative enterprises Acta Universitatis CIBINIENSIS, vol XXI, Sibiu, pp.13-17, ISBN 1221-4949, (1995). 3. Manolea, Gh. and others PROCOMAND – equipment for the aquisition of system parameters for electric actions. National colocvium „Methods, installations and equipments for the energy management and preservation”, 5th edition, Craiova, pp 163-165, ISBN 973-0-00917-1, (1999). 4. Manolea, Gh. The innovation at the point between technical high education and research. 4th National Symposium ,,Transdisciplinary perspective across creativity and creation. Innovation paradigm in Romania”. Romanian Academy. Engineering sciences department, (1995). 5. Manolea, Gh, The Invention Implementation Center Craiova, regional interface for education-research and small companies. International Regional Symposium YugoslaviaRomania-Hungary „Regional interdisciplinary research”, Timi oara., (1996). 6. Manolea, Gh. Innovation Center for Engineering and Technology Transfer, management model of the research human resources. Sesiunea jubiliar Electroputere '99, Craiova., (1999)
solution was chosen. There were built several samples of connections which were tested. The reduction of the contact resistance was from 20 μ to 12 μ . The technological animation was repeatedly discussed between the engineers from Cummins and professors [17] (fig.14), (fig.15)
Fig.15 After discussions at faculty 7. Manolea, Gh. The success of The Invention Implementation Center Craiova regarding innovation and technology development – case study. Symposium „Communication, innovation and transfer technologies for small and medium companies”, Bucure ti, (1998). 8. Manolea, Gh. Innovation and Technology Transfer Center entrepreneurship structure model. Summer school „University in society” UNISO 2002, Drobeta Turnu Severin, (2002). 9. Manolea, Gh., Novac, Al., Nedelcu , C. Electrical heating system with distributed elements, guided through microcontroller SIR DUNA 2000. Installation Technique. No.2/2003, pp.30-35, (2003). 10. Manolea, Gh. The innovation and technology transfer, capitalization methods for the research and creative potential from universities. Journal of science policy and scientometric,. no.3/2003, pp.121-127, (2003). 11. Manolea, Gh. Le transfert technologique-solution de valorification des resultats des recherches scientifiques. Buletinul Institutului Politehnic din Iasi, Tomul LII (LVI), Facicula 5, pp.159-168, ISSN 1224-5860, (2006). 12. Manolea, Gh., Nedelcu , C., Novac, Al. Heating system of the incubation area for the Pleurotus type mushrooms, Proceedings of the 14-th National Conference on Electrical Drives, September 25-26, Timisoara, Romania, pp. 157-162, ISSN 1582-7194, (2008). 13. Nedelcu , C. and others The automation and supervision of the cultivation environment for horticulture products-functionary food. Buletinul Institutului Politehnic din Iasi, Tomul LII (LVI) Fascicula 5A, pp. 123-128, ISSN 1223-8139, (2006). 14. http://em.ucv.ro/cercetare/ciitt 15. Order of Industry Minister no. 3204 of 24.01.1992 regarding the reorganization of the activities in the domain of inventions 16. Romanian Standard SR 13547- Business development model by innovation – 2012 17. http://gheorghe.manolea.ro
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EVOLUTION OF LIGNITE EXPLOITATION IN THE COAL PITS OF ROVINARI COAL BASIN Dumitru FODOR*, Petre DIACONESCU**
Abstract Rovinari Coal Basin represents a very important mining entity for Romania’s economy. In 60 years of continuous activity, it has been extracted and capitalized over 430 mil. tons of lignite. Today, into the coal basin are highlighted the industrial reserved by leased of approximately 180 million tones, accounting for the continuation of the activity, at the current capacity of 6 million tons/year, for a period of at least 30 years. Balta Unchia ului coal pit was the first coal pit opened in the basin, then followed by Beterega and Cicani coal pits and Urdari coal pit was the last one, which was put in service in 1987. Currently, in the Rovinari Coal Basin works the following coal pits: Gârla, Rovinari, Tismana I, Tismana II, Pinoasa, Ro ia de Jiu, Pe teana South and Pe teana North. Balta Unchia ului, Cicani and Beterega coal pit, were closed because they have exhausted the reserves, and Urdari coal pit has been closed because the unfavorable economical and technical results. 1. Introduction The beginnings of exploitation and capitalization of lignite deposits from Gorj County, dates back to the period from 1916 to 1917, when it was removed manually from the crop of lignite layers from Rovinari Coal Basin, about 1000 tons of coal. In 1924 the first underground mine was opened for lignite exploitation from Rovinari Basin, during the years 1924-1929 was a production of almost 3,200 tons of lignite. After this period due to the economic crisis and the events that followed, including the World War II, the activity is interrupted and it will be resumed in 1950. _____________________________ * Prof.eng.Ph.D University of Petro ani ** Eng.Ph.D stud.University of Petro ani
Geological investigations undertaken beginning in this year, highlighted the existence of important reserves of lignite both in Rovinari Mining Basin and in surrounding areas as well. At that time, were highlighted the particularly advantageous conditions of surface mining of lignite reserves in the Jiu, Jale and Tismana meadow. As a result, parallel to the underground exploitation is to exploit the lignite deposits from Rovinari Mining Basin. At the beginning, the exploitation was done in small coal pits having discontinued technology flow, after which it moved on to larger coal pits equipped with continuous technology flow with modern high-capacity machines and increased productivity. Prospecting activity continued throughout Oltenia, highlighting the new coal reserves in Motru, Jilt, Husnicioara and Berbe ti-Alunu, within have been designed and put into service new mines and coal pits. Of the 12 coal pits designed and put into operation in Rovinari Coal Basin, so far have been exploited and flat-out the Balta Unchia ului, Cicani and Beterega coal pits, Urdari coal pit has been closed and still in operation: Gârla, Rovinari East, Tismana I, Tismana II, Pinoasa, Ro ia de Jiu, Pe teana South, Pe teana North, located in the north-western part of the mining basin adjacent to the Rogojelu power station and extended to the South to the Turceni power station (figure 1). Geological speaking, the lignite deposits from Rovinari Basin, belongs to the Pliocene stratum (Romanian, Dacian, and Pleistocene) and consist of 17 lignite layers, from which are entirely exploited the layers V, VI and VII and from VIII to XII are locally exploitable in areas where the thickness exceeds 1.0 m. Layers I to IV are not exploitable because of the aquifer sands from the bed and layers XIIIXVII insular appear being mostly flat-out.
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Fig. 1 Coal pits location in Rovinari Coal Basin The average thickness of a layer varies between 4 and 8.0 m, and the coal complex, in the case of many layers, the thickness is 100-120 m, in the hilly areas and 20-40 m in meadow areas (figure 2).
Fig. 2 Geological sections through Rovinari Mining Basin Rocks from the bed and roof of lignite layers are generally poorly consolidated and made up of vegetable soil consisting of 5-20%, clays and marl, 50-70% and sans 5-20%.
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In terms of quality, the lignite from deposits has a calorific power of 2.000-2.200 kcal/kg. Through the excavation process there is a dilution, as a result of the addition of sterile, which leads to obtain a lignite with a calorific power of 1.500 – 1.800 kcal/kg. The deposit has an angle up to 50 with undulation on many directions and being interrupted by a series of major faults on East-West direction. 2. Presentation and case analysis of coal pits from Rovinari coal basin 2.1. Coal pits with discontinuous technological flow Balta Unchia ului coal pit The first coal pit put into service in Rovinari Mining Basin and in Romania as well, was Balta
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Unchia ului coal pit. This coal pit was opened in 1955 in the meadow of the Jiu river, in the most favorable conditions from the point of view of stripping ratio. Until completion of the technological process of Balta Unchia ului coal pit, was need to experiment more kinds of excavation, transportation and dumping machines which impress an experimental character to the coal pit. In the coal pit activity are distinguished two stages: - Stage I is characterized by making the stripping with a dragline excavator type Markwart E200 (Figure 3) with lignite transport with a belt conveyor band to the exterior dump, from where the sterile material is conducted throughout the Jiu river bed by a monitor working at a pressure of approx. 10 atmospheres, on a dumping bridge, adapted to a stepping dragline.
Fig. 3 Stage I of exploitation for Balta Unchia ului coal pit stripping by a Markwart E-200 type bucket-chain excavator In 1959, it gave up of using the bucket-chain excavator because the cutting effort used for clay and marl rocks was superior to the cutting force of excavator's cups, of which, the excavation capacity was significantly reduced and the wear of cutting equipment was high.
- Stage II represents the completion of the technological process from Balta Unchia ului coal pit. This stage is characterized by making the stripping with discontinuous action excavators and sterile transport with dumpers to the interior dump, (figure 4).
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Fig. 4 Design of exploitation method from Balta Unchia ului coal pit – Rovinari, in stage II of activity Coal extraction was done in both cases in the first and the second stage, in coal pit faces of 10 m wide and up to 9 m height, with discontinuous action excavators like mechanical shovel type with bucket capacity of 1.0-1 á 1.5 m3, and transportation of useful material was done with belt conveyors with rubber mat width of 1000 mm and speed of 1.2 m/s to selection station, ensilage and shipping. Were used excavators type SE-3 and Ry-1.5, stepping dragline type ES-1, Kirov scrapers, "Red Flag" and Molotov dumpers. The maximum production of this coal pit was 582.000 tones per year. 2.2 Coal pits with continuous technological flow Technologies in continuous flow extraction of sterile and useful material with bucket and cutting buckets excavators and transport of excavated material using belt conveyors with high-capacity belt, were applied for the first time in Romania in
1967 in Rovinari Mining Basin, in Cicani coal pit and in 1969 in Beterega coal pit, based on technology projects drawn up by German companies. At the beginning the lignite pits from Rovinari Basin, equipped with continuous technology was applied the operation method by transport the sterile to the interior or exterior dumps beside the available place for dumps location (figure 5). The technology flow used for extracting the sterile was made by excavation machines, belt conveyors with specific elements of switching and dumpers. The extracted coal from working front was transported from the coal pit to the coal yard, equipped with specific dumping machines and taking out the production for being sent to the beneficiary. So each machine from the technological has it own task to achieve the production process as a whole.
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Fig. 5 Exploitation method with continuous transport of sterile rocks in interior dumps, used in the coal pits of Rovinari Mining Basin Bucket excavators are responsible for the excavation of working benches within the exploitation perimeter in blocks with a width of 45 ÷ 55 m (figure 6). Vertical, the working front can be developed only in sterile or only in coal or in a mixed formation - sterile and coal. Bucket excavator and cutting buckets excavator can excavate both above and below the displacement level.
Fig. 6 Bucket excavator type ERc – 1400 Excavation above the displacement level is made by straight buckets placed on rotor (+15m÷ +30m) and for excavation of a bench located under
30 and its location into the working front 7 the displacement level, the excavation is made by back-acting buckets placed on rotor (-3,5m÷-7,0m), figure 7.
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Fig. 7 Working possibilities of Sch Rs 1400 The bucket excavators types currently used in Rovinari Mining Basin are: SRs 2000-30/7 type, ERc 1400-30/7 type, SRs 1300-28/3,5 type and exceptional ERc 470 -15/3,5 + CBs 1200 type. Technological flows from coal pits of Rovinari Mining Basin have 33 functional bucket excavators, which can ensure an excavation capacity of approx. 83.000 m3/h. High capacity belt conveyors (TMC) make the excavated material in the distribution joint, and from there to the coal yard and inside or outside dumps of the mining perimeter. Practically all the TMC make up the composition of technological flow and ensuring the transport of excavated mass and represents the moving vector into a coal pit. TMC can be stripped when it make up the front technological flow for a bucket excavator or dumper and can be stationary when it makes up the main transport circuits to the coal yards or dumps.
30 excavator 7
The TMC may be fitted with carts on tracks (MAN) in order to achieve the switches in the distribution joint or can be special constructed with "extensible head" in order to switch into the coal yards. The currently used types of TMC are the ones with the width of the rubber mat of 1400รท1600รท1800รท2000รท2200mm with metal insertion, or in special cases being used rubber mats with textile insertion (figure 8). The technological flows of coal pits belonging to Rovinari Mining Basin have currently in operation a total of 165 pieces of TMC with a total length of approx. 115 km. The high capacity belt conveyors (TMC) represent a part of the technological flow where are concentrated the highest cost of electricity with rubber mat, idlers, with additional and monitoring machine, where from result their up to date and decreasing of transport length.
Fig. 8 High capacity belt conveyor (B=1800mm)
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The knee-type dumpers ensure the deposition of sterile materials into dumps which can be internal or external. The deposition is done generally in deposition blocks with a maximum width of 45 ÷ 90 m in high-bench or under track (low bench), figure 9. If they are located on the floor of the coal pit and are used with bucket excavators it would
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perform the transshipment of sterile in the dumps. The currently used types of machines are A2Rs-B 6500x90, A2Rs-B 6300x95, A2Rs-B 4400x170, A2Rs-B 12500x95 and A2Rs-B4400x60. Knowing that the stripping ratio has increased substantially over time, these machines have had and would have an increasingly annual targets.
Fig. 9 The knee-type dumper and the deposition mode of the material into the dump Dumping/dumping and i taking out machines (AsG, KSS) ensure the deposition of coal into the coal yard. These machines are part of technological flows quite complicated where is
ensured the deposition, taking out and transfer of coal from the coal pits to the power station or loading points into cars (figure 10).
Fig. 10 The mixed machinery of deposition and loading the coal from the coal yard 1- input belt; 2- loading-deposition belt; 3- roller; 4- taking-over mass; 5- delivery shaft; 6-displacement system; 7- transportation belt
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Revista Minelor - Mining Revue no. 3 / 2012
The technological flows of coal pits belonging to Rovinari Mining Basin have currently in operation a total of 25 pieces of knee-type dumpers and 16 pieces of dumpers, which can provide a storage capacity of approx. 150,00 m3/h, and a coal storage capacity greater than 0.6 mil tons in stock. Cicani coal pit The Cicani mining perimeter is located on the left bank of river Jiu, between the mining perimeters Gârla North and Beterega South. It has been exploited the layers V,VI and VII from the 17 th lignite layers of the basin. The layers have the width of 1,5 ÷ 5m, angles up to 5º, having undulation on many directions, being interrupted by
a few faults. The industrial reserves from this perimeter were approx. 15 mil. tons from which have been exploited 14.133.656 tons of lignite. In terms of quality, the lignite from this deposit has a calorific power of 1800-2200 kcal/kg. By exploitation process there is a dilution, because it’s not possible to separate the interlayer under 0.4 m, which conduct to a calorific power of 1750÷1820 kcal/kg. The evolution of coal production and the sterile from the stripping ratio is shown in Figure 11. The average stripping ratio was 1,61/1(m3/t). In Cicani coal pit has been applied the method of transport the sterile rocks to the interior dump.
(mc, tone)
(pers.)
4.500.000
400 377
380 315
3.953.986
357
342
4.000.000
350
315
3.500.000
300 2.854.997
3.000.000
2.322.259
2.402.850 1.933.457
2.000.000
250
244
2.500.000
1.500.000
3.145.420
250 2.179.384
2.270.951
2.066.261
1.902.660 1.868.865
104
1.199.336
500.000
2.144.623
150
1.813.609
1.440.256
1.000.000 801.052
195 200
100
STERIL 985.104
983.846
CARBUNE 50
574.727
Nr.pers.
97.707 0
0 1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
Fig. 11 The evolution of coal production in Cicani coal pit The technical equipment was: bucket excavators, 2 pieces of SRs 470 type, a knee-type dumper ARsB2500x50, a CBs 1200, 8 pieces of TMC 1200 type, with a total length of approx. 7.5 km. The technological flow presented in figure 12 dumps the excavated sterile in the interior dump and the coal is transported into a coal yard with a capacity of approx.1500 tons from a loading point.
The Cicani coal pit was closed in 1974 because the coal deposit went flat. The hole of the coal pit was used in the first phase for dumping the sterile from Beterega coal pit, after which it was used to dump the ash from Rogojelu power station of Rovinari Energy Complex. In a few years the dump of Cicani coal pit was arranged and integrated to agricultural circuit.
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SRs 470-18/1,5
T1 T2 T4 SRs 470-15/3,5
T3
T21 A2RsB 2500x50
T22
T5 Siloz Carbune
T23
Legenda TMC. carbune TMC. steril SRs 470-15/3,5 excavator cu rotor A2RsB 2500x50
Punct de incarcare in vagoane
masina de haldat
Fig. 12 Technological flow from Cicani coal pit In Beterega coal pit was applied the method of transport the sterile rocks to the exterior dump. The technical equipment was: 3 bucket excavators type SchRs 400 12,8/5, a knee-type dumper A2Rs B4400x60, 3 CBs 1200, 7 TMC type 1200, 1400 with a total length of approx. 8,95 km, 2 pieces of slope bridge with 50 m length with a belt conveyor with a width of 1600mm. The technological flow shown in Figure 14 deposit the excavated sterile into the exterior dump of Cicani and the coal was transported into the coal yard of Rogojelu.
Beterega coal pit The Beterega mining perimeter was located in the meadow area of Rovinari Basin, to the South of Cicani coal pit. The industrial reserves were approx. 20 mil. tons from which 19.566.742 tons of lignite were extracted, with an average stripping ratio of 1,78:1 (m3/t). The layer V had a width of approx. 5,5m. The calorific power of extracted coal was 17851855 kcal/kg. The evolution of coal production, sterile and employees is shown in figure 13.
(pers.)
(mc, tone) 6.000.000
600 5.476.680 4.992.972
5.000.000
500
498
450
450
4.780.963 450
3.994.377 4.000.000
400
3.779.008 3.779.663 3.278.485
3.039.478
3.070.662 3.000.000
300
2.814.020 237
229 268
261
2.000.000
277
1.898.442
2.433.550 200
1.747.452
1.506.394
1.751.257 123
1.451.428
129
1.285.363
1.453.115
1.000.000 764.533 41
100
STERIL CARBUNE
870.955
Nr.de pers.
131.824
94.000
18.200
0
0 1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
Fig. 13 The evolution of coal production in Beterega coal pit
1980
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Revista Minelor - Mining Revue no. 3 / 2012
Rovinari East coal pit. The hole of Beterega coal pit is used today to dump the ash from Rogojelu power station.
The Beterega mining perimeter was closed in 1980 because the coal deposit went flat.. Continuing the exploitation to the East of Beterega coal pit represented actually the opening of
Flux tehnologic cariera Beterega A2RsB 4400x60 T53/54
T51 T60
T59
T IX T VIII T VI e1315
SchRs 400-13/5 T18 Depozit de carbune Rogojelu
e1318
SchRs 400-13/5
Legenda TMC carbune TMC steril SchRs 400-13/5
T48/49 SchRs 400-13/5
e1316
excavator cu rotor
A2RsB 4400x60
masina de haldat
Fig. 14 Technological flow in Beterega coal pit 1967 is the year base for the Romanian coal pits, because of the start of the first modern technological line with a bucket excavator (SRs 470), belt conveyors with textile insertion with B=1200mm and a knee-type dumper (ARsB2500x50) at Cicani coal pit. Development of
these working technologies in lignite extraction, has guided for a long time the Romanian energy strategy, thus in Rovinari Mining Basin have been opened new coal pits (Figure 15): G창rla, Tismana I, Ro ia de Jiu etc. Cariera Urdari Cariera Pinoasa Cariera Pesteana Nord Cariera Tismana II Cariera Pesteana Sud Cariera Rovinari-Est Cariera Rosia de Jiu Cariera Tismana I Cariera Garla
Cariera Beterega Cariera Cicani 1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
Fig. 15 The coal pits from Rovinari Mining Basin If the designed production capacity of the first coal pits with continuous technological flow were small, respectively for Cicani and Beterega were 1.350 thousand tons/year, according to the existing technical equipment like bucket excavator type SchRs 400 12,8/5, transport circuits made of TMC with textile insertion belt with a 1.200-1.400 mm width, today, the production capacities have increased, so that Pinoasa and Ro ia de Jiu coal pits have a production capacity of 3.500 thousand tons/year respectively 4.400 thousand tons/year. The technical supply from the coal pits of Rovinari Basin has bucket excavators like
ERc1400 2000
30 26 type, SRs1300 type and SRs 7 3,5
30 type, high capacity belt conveyors with a 7
metallic insertion in the rubber mat, having a width of 1.400-2.200 mm, knee-type dumpers with deposition capacity of Q = 4.400-12.500 m3/h and the length of L = 60-170 m. The evolution of Rovinari Mining Exploitation from 1967-2011, being considered a standard for Romanian coal pits is shown in figure 16. The mining perimeters from
ISSN-L 1220 – 2053 / ISSN 2247 -8590 Universitas Publishing House, Petroşani, Romania
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that time were: Cicani, Beterega, Gârla, Tismana I, Tismana II, Rovinari East and Pinoasa from 2002. It has to be highlighted the continuous growth of the coal production from 1989 when Rovinari Mining Exploitation has extracted 12.24 mil. tons, and the stripping sterile was 44,48 mil. m3. After 1990 the coal production has decreased because of the major changes of the society, having a minimum in 1999 of 3.32 mil. tons with 23.86 mil. m3 of sterile, and also because of the workers
dismissing in 1997. Today, the coal production is approx. 6.5 mil. tons of extracted coal with a stripping ratio of approx. 7.0:1 (m3/t). It is obvious the increase of stripping ratio, which was 3:1(m3/t) in 1981 and after 30 years has become 6.65:1(m3/t) in 2011, in conditions of developing the coal pits to the final limit (Gârla, Rovinari East) and others have moved to the hilly area (Tismana I and Tismana II).
(pers.)
(mil.mc,mil.tone)
3500
60,00 STERIL
52,19
50,00
2878
2888
LIGNIT 44,48 nr.personal
2573
3000 47,44
2630
45,34
44,83 2551
2500 38,71
2343
40,00
40,34 42,32 36,89
31,75
30,00
1582
1500
27,60
24,24 1210
20,00
23,86 16,60
907
1000 12,10
10,00
10,37 8,92
9,93
5,23
1,93 1,44
0,98
8,16
8,30 6,78
7,79
12,24 8,26
7,08
380
3,66
5,21 6,93 3,89
6,14 5,29
6,80
6,79
500
5,59 5,76
19 71 19 73 19 75 19 77 19 79 19 81 19 83 19 85 19 87 19 89 19 91 19 93 19 95 19 97 19 99 20 01 20 03 20 05 20 07 20 09 20 11
19 6
7
0 9
0,00
19 6
2000
31,34
Fig. 16 Evolution of coal production at Rovinari Mining Exploitation Nowadays, the most representative coal pits from Rovinari Mining Basin are: Tismana, Rovinari and Pinoasa coal pits which have the technological flows presented in figures 17, 18 and 19 and in table 1 are shown their economic results from 2011.
Today, the extraction of coal from Oltenia Mining Basin is made by SNL Oltenia Târgu-Jiu SA, SC Rovinari Energy Complex SA, SC Turceni Energy Complex SA and SC Craiova Energy Complex SA from the leased perimeters, which ensure the lignite demand from Romania.
Table 1 Economic results of the coal pits from Rovinari Mining Exploitation
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Revista Minelor - Mining Revue no. 3 / 2012
Fig. 17 Technological flow in Rovinari coal pit
Fig. 18 Technological flow in Tismana coal pit
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Fig. 19 Technological flow in Pinoasa coal pit 3. Conclusions References The first coal pit opened in Romania was Balta Unchia ului from Rovinari Mining Basin, which from 1955 has practiced different extraction methods. The continuous and discontinuous technology flow of sterile and lignite extraction with bucket excavators and cutting buckets and transportation by high capacity belt conveyors of excavated material, have been applied for the first time in Romania in 1967 in Cicani coal pit and in 1969 in Beterega coal pit, using German technological projects. Exponential development of lignite extraction in the coal pits of Rovinari Mining Basin and the lately progress are a result of an update of transport systems and equipment from the technological flows. To satisfy the demand in 2013-2030 must highlight the existing perimeters and satisfy the research for capitalizing the new perimeters. Therewith the expropriation procedures have to be improved for a better efficiency of lignite extraction.
1. Diaconescu P, Scientific research report – The influence of the technologic equipment modernization on the production capacity of the tech lines. 2. Fodor D. The open pits exploitation of useful minerals and rocks. vol.1 i 2. Editura Corvin, Deva, 2008 3. Huidu E. Mining monography of Oltenia - vol. I Rovinari Basin 1950-2000 - Editura Funda iei Constantin Brâncu i Târgu - Jiu -2000 4. Jescu I. The lignite extraction through open pit exploitations in România - Editura Tehnic Bucure ti 1981.
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BIOTECHNOLOGICAL REMOVAL OF HEAVY METALS FROM MINING WASTEWATERS BY DISSIMILATIVE SULPHATE REDUCTION Svetlana BRATKOVA*, Anatoliy ANGELOV*, Alexandre LOUKANOV** Katerina NIKOLOVA*, Sotir PLOCHEV*, Rosen IVANOV* Abstract: Acid drainage wastewaters contaminated with Cu – 200 mg/l, Fe – 20 mg/l, Zn – 20 mg/l, Ni – 10 mg/l, Cd – 10 mg/l and Co – 10 mg/l were remediated by hydrogen sulphide precipitation reaction in laboratoryscale installation. The installation design includes anaerobic bioreactor, chemical reactor and settler, connecting in series. The recirculation of treated wastewater from settler to anaerobic bioreactor was performed by peristaltic pumps. Sulphate-reducing bacterial consortium is adhered in biofilm, which is immobilized on zeolite particles in the anaerobic bioreactor. The bacteria were cultivated on a medium containing lactate as a source of carbon and energy. Heavy metals removal was achieved in a chemical reactor by biogenic produced H2S and bicarbonate ions. In addition, X-ray diffraction analyses proved that the precipitated above heavy metals are mainly in forms of relevant insoluble sulfides and carbonates. In batch conditions was investigated also the resistance of sulfatereducing bacteria to various heavy metals. The reported treating method allows to removes heavy metals from wastewaters below the permeable level for water intended for use in the agriculture and/or industry.
mines. Wastewater generated from mining industry is often acidic and typically characterized by a significant content of sulphates and soluble metals, such as Zn, Fe, Cu, Ni, Pb and Cd. Sulphate rich wastewater is derived also by many industrial processes that use sulphuric acid. Conventionally, hydroxide precipitation is the most commonly applied method for the treatment of metal containing waters. There are some serious limitations in terms of application and effectiveness in this treatment. The production of high quantities of sludge is the main disadvantage of the method. Also, sulfate removal is only possible when Ca2+ containing chemicals, such as lime, are used for neutralization. In recent years, the use of sulphate reducing bacteria (SRB) to reduce sulphate and precipitate metals has been proposed as an alternative to hydroxide precipitation (Kaksonen and Puhakka, 2007; Liamleam and Annachhatre, 2007; Hoa et al., 2007; Costa et al., 2007]. Sulphate-reducing bacteria oxidaze simple organic compounds (such as lactate, acetate, butirate and other products of fermentations) with sulphate under anaerobic conditions:
Keywords: Acid mine drainage, sulphatereduction, bioreactor, heavy metals, metal sulphides.
M2+ + H2S MS + 2H+ (3) where M includes metals such as Fe, Cu, Zn, Ni, Cd. Numerous reactor designs for microbial sulphate reduction have been reported (Kaksonen et al. 2004; Bayrakdar et al. 2009; Nagpal et al. 2000; Steed et al. 2000; Nevatalo L. et al. 2010). Biological sulfate reducing reactors used for metal precipitation can have either one or more stages, i.e. the sulfate reduction and metal precipitation can occur simultaneously, or in separate process units. Single-stage processes are low-cost to operate, but it may not be viable if the treated wastewater is high acidic or contains high concentrations of heavy metals (Hao, 2000). Metals can be preprecipitated to the biological step by reaction with sulphide- or H2S- containing solution. The
1. Introduction Acid mine drainage is a major environmental hazard that affects the aquatic ecosystems around _____________________________ * Laboratory of General and Geological Microbiology, Department of Engineering Geoecology, University of Mining and Geology “St. Ivan Rilski”, Sofia, Bulgaria ** Laboratory of Engineering NanoBiotechnology, Department of Engineering Geoecology, University of Mining and Geology “St. Ivan Rilski”, Sofia, Bulgaria
2CH3CHOHCOOH + SO42- 2CH3COOH + H2S + 2HCO3- , 2-
(1) -
CH3COOH + SO4 H2S + 2HCO3 ,
(2)
-
The HCO3 ions increase pH and alkalinity of the water. The soluble sulfide reacts with the metals in wastewater to form insoluble metal sulfides:
ISSN-L 1220 – 2053 / ISSN 2247 -8590 Universitas Publishing House, Petroşani, Romania
separation of microbial sulphate reduction and metal precipitation alleviates toxicity on SRB. The stoichiometry of sulfide addition to the metal solution should be carefully controlled, because the unreacted sulfide remains in the solution and needs to be removed (Veeken et al. 2003). Cadmium, copper, iron, lead, mercury, nickel, and zinc are some of the metals that precipitate as metal sulphides. Arsenic, antimony, and molybdenum form more complex sulphide minerals. Metals such as manganese, iron, nickel, copper, zinc, cadmium, mercury, and lead may also be removed to some extent by co-precipitation with other metal sulphides. The present work study the treatment of acid wastewaters containing Cu, Fe, Zn, Ni – 10, Cd and Co by means of laboratory-scale installation. The two processes – microbial sulphate-reduction and formation of insoluble metal sulphides are divided into separate reactors. The composition of the metal precipitates in vertical-flow settler was determined. 2. Materials and methods Mixed SRB culture was obtained from a laboratory anaerobic cell with mixed solid organic matter (cow manure, spent mushroom compost and sawdust) for treatment of model acid mine water solutions. Modified Postgate medium was used for the cultivation of SRB. It contained per liter of distilled water: K2HPO4 - 0.5g, NH4Cl - 1.0g, Na2SO4 - 2.0g, CaCl2 - 0.1g, MgSO4.7H2O - 4.0g, FeSO4.7H2O – 0,5g sodium lactate - 6.0g, yeast extract - 0.25g. The initial pH is adjusted to 6.5. The formation of ferrous sulphide was detected as a black precipitate. It indicates that bacterial growth had taken place. 2.1 The effect of Fe, Cu, Zn, Ni, Co and Cd on dissimilatory sulphate reduction Experiments with heavy metals were carried out using the modified nutrient medium, which does not contains Fe(II). Batch experiments were carried out in 20 ml glasses bottles heavy metals and nutrient solution. Iron (FeSO4.7H2O), copper (CuSO4.5H2O), zinc (ZnSO4.7H2O), nickel (NiSO4.7H2O), cobalt (CoCl2) and cadmium (CdCl2.5H2O) were added separately to the bottles reach to final concentration in the range of 0.01 to 2 g/l for the different experiments. The initial pH was adjusted to 6.0. 2.2 Treatment of waters polluted with heavy metals by the laboratory installation The laboratory installation for heavy metals removal from waters is given in fig.1. The geometric volume of an anaerobic fixed bed reactor
23
(2) is 1.2 dm3 and it is filled with 1.13 kg zeolite and 0.67 dm3 modified Postgate medium. The anaerobic bioreactor is inoculated with 40 ml enriched microbial culture of sulfate-reducing bacteria. After formation of active biofilm of SRB, the reactor was kept with medium feeding and continuous cultivation. Nutrient medium (1) is fed with adjustable flow rate into the bioreactor through a peristaltic pump (9). Homogenization in the reactor is due to upward flow performed by a recirculating pump (11). A sand filter (7) is provided in the scheme to precipitate the insoluble particles. The microbial produced H2S is in contact with the solution of heavy metals in a chemical reactor (4). The solution of heavy metals is fed into the chemical reactor through a peristaltic pump (10) from tank (3). The geometric volume of the reactor is 0.5 dm3. The insoluble sulfides precipitated in a vertical-flow settler with a volume of 0.85 dm3. The greatest part of the effluents of settler was pumped into mix tank by a recirculating pump (13). The other part of effluents accumulates into collector tank (8) with volume of 6 dm3. Adjustable flow peristaltic pumps (10 and 11) support the necessary volume loading rates with sulfates in the bioreactor and the maintenance the total organic carbon content to final electron acceptor ratio of 0.67. The concentrated medium with lactate was used for the cultivation of SRB. It contained per liter of distilled water: K2HPO4 - 1.0 g, NH4Cl - 2.0 g, CaCl2 - 0.5 g, sodium lactate - 16.0 g, yeast extract - 1.0 g. The initial pH is adjusted to 7.0. The heavy metals Cu – 200 mg/l, Fe – 20 mg/l, Zn – 20 mg/l, Ni – 10 mg/l, Cd – 10 mg/l and Co – 10 mg/l are involved in the synthetic solution in the forms of CuSO4.5H2O, FeSO4.7H2O, NiSO4.7H2O, ZnSO4.7H2O, CdCl2.2.5H2O and CoCl2. The other ingredient of synthetic solution of heavy metals is MgSO4.7H2O - 2.5 g/l. The pH of the solution is adjusted in the range of 2.5 – 2.7 with 1 N H2SO4. The experiment is performed at temperatures ranging from 21oC to 22 oC. 2.3 Analytical methods In some certain sampling points of the installation are determined the parameters pH and Eh, mV. In the same points are conducted spectrophotometrical measurments of the concentrations of sulfates using BaCl2 reagent at a wavelength of 420 nm and of hydrogen sulphide using a Nanocolor test 1-88/05.09 at a wavelength of 620 nm. The concentration of heavy metals was measured by ICP. X-ray diffraction (XRD) patterns were obtained with a DRON-1 diffractometer (CuK radiation, Ni filter, I = 20 mA, U = 30 kV) and a 57.3 mm Debye-Scherrer TUR–M–60 camera.
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Numbers of sulphate-reducing, anaerobic heterotrophic and fermenting sugars bacteria with gas production in the liquid phase of anaerobic bioreactor are counted through standard microbiological methods, including those of most probable number and colony-forming unit on plate with nutrient agar.
3. Results and discussion 3.1 The effect of Fe, Cu, Zn, Ni, Co and Cd on dissimilatory sulphate reduction The effect of heavy metals on microbial sulphate reduction was estimate after 14 days of incubation. The data about established growth of sulphate reducing bacteria in different concentration of heavy metals are sowed in table 1.
9 5
2
13
1
11 10
6 7
3
4
8 12
Fig. 1 Schematic diagram of the laboratory installation for active treatment of wastewaters polluted with heavy metals: 1 – Nutrient medium tank, 2 - anaerobic fixed-bed biofilm reactor, 3 - Heavy metals solution tank 4 – chemical reactor, 5 - mix tank, 6 – settler, 7- sand filter, 8 - collector tank, 9 and 10 – peristaltic (roller) pump, 11 and 13 – recirculating pump, 12 – sludge During incubation, black precipitate was detected on the bottom of all glasses bottles at the concentrations of ferrous ions in range 0.01 to 2.0 g/l. However, it was found that bacterial growth is strong affected by the presence of the other studied metal ions. Reduction of sulphates was carried out at maximum concentration of Co and Zn respectively 0.6 and 0.2 g/l. Copper and zinc have strong inhibitory effect on enrichment mixed culture of sulphate-reducing bacteria at concentrations above 0.06 g/l. Bacterial growth was found only at 0.01 g/l cadmium. Experiments with heavy metals showed that cadmium toxicity to this mixed SRB culture is highest. The reported toxic concentrations of heavy metals to sulphate-reducing bacteria in different studies range from a few mg/l to as much as 100 mg/ (Utgikar l.et al. 2002). Cabrera et al. (2006)
reported that the relative order for inhibitory metal concentration was Cu >Ni >Mn > Cr > Zn for two cultures of SRB (Desulfovibrio vulgaris and Desulfovibrio sp.), as an increase in the metal concentration in solution led to a decrease in the sulphate reduction rate and this effect was accompanied by a low level of metal precipitation. In other study (Medircio et al. 2007) were assessed the effects of cadmium and manganese at concentrations 20 mg/l on the SRB growth rates and the batch experiments showed 90% manganese and 85% cadmium precipitation. 3.2 Treatment of waters polluted with heavy metals by the laboratory installation The adherence of active biofilm of SRB onto the natural occurred zeolite is carried out for a period of three months. For this purpose the
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rates of microbial sulphate-reduction are estimated in previous studies (Bratkova et al. 2011). During this study with the same fixed bed bioreactor was established a maximum rate of sulphate-reduction 273 mg SO42-/l.h at initial concentration of sulphates – 3 g/l and the residence time is 10.5 h.
Postgate medium is inoculated with obtained mixed SRB culture. For a period of some months progressively is decreased the residence time and respectively increases volume loading rate of the bioreactor with sulphates. The data about Influence of SO42- volume loading rates (SO42-g/l.h) to the
Table 1. Growth of SRB in different concentration of heavy metals Fe Cu Zn Ni Co Cd
0.01 + + + + + +
0.02 + + + + +
0.04 + + + + +
0.06 + + + + +
Concentration of heavy metals, g/l 0.08 0.1 0.2 0.6 + + + + +
+
+
+
+
+
The other important parameter is total organic carbon/SO42- ratio (Vossoughi et al. 2003). Velasco et al. 2008 reported that the feed COD/SO42- ratio can be an useful parameter to control hydrogen sul de production in the metal precipitation process when ethanol is used as sole electron donor and carbon source. Kaksonen et al. 2004 showed that the stoichiometric COD/SO42- ratio of 0.67 was adequate to attain around 60% of sulfate reduction with an initial sulfate concentration of 2000mg/L in a uidized-bed reactor inoculated with SRB capable to completely oxidize ethanol to CO2. Cao et al. (2009) reported that when lactate is used as sole electron donor, while COD concentration increased from 963 mg/L to 17330 mg/L with the same concentration of SO42-, sulfate removal rate
0.8 +
1.0 +
1.5 +
2.0 +
+
increased and strong sulfate-reducing activity was achieved under the initial COD/SO42- ratio of 3.0. In this study the stoichiometric total organic carbon content to final electron acceptor ratio is 0.67. The concentration of sulphates in the solution of heavy metals is in the range 1.10 - 1.15 g/l. Both adjustable flow peristaltic pumps (for polluted acid water and nutrients) support the maintenance of volume loading rates with sulfates of the fixed-bed sulphate-reducing reactor in the range of 190 - 200 mg/l.h. In the course of this volume loading rate and COD/SO42- ratio 2.7, the rate of microbial sulphate-reduction is in the range of 180 - 185 mg/l.h. It was found the removal of heavy metals from polluted waters in the range 98.9 - 99.9% (Table 2).
Table 2 General parameters measured in sample points at the outlets of main facilities of the laboratory installation Parameter h, mV SO42-,g/l H2S, mg/l Cu, mg/l Fe, mg/l Zn, mg/l Ni, mg/l Cd, mg/l Co, mg/l Removal of heavy metals ratio, %
Solution of heavy metals 2.50 – 2.73 1.09 – 1.23 194.8 – 207.3 18.9 – 20.86 17.6 – 21.44 8.81 – 9.72 9.35 – 10.29 9.32 – 10.17
The effluents contain low concentration of sulphates – 0.11 – 0.12 g/l. Also the excess amounts of H2S are determined in the sample points after chemical reactor and settler. This result shows that it is necessary to perform precise dosing of flow rates into the chemical reactor and maintaining the optimal ratio between the concentrations of heavy metals and that of microbial produced sulphide or after the settler to be provided the necessary
Outlet of the anaerobic bioreactor 7.56- 7.80 - 231 - -258 0.08 – 0.10 24 – 37 0.01 – 0.08 0.42 – 1.43 0.21 – 2.76 0.08 - 0.21 0.006 – 0.01 0.026 – 0.04
Outlet of the settler 7.46 – 7.69 -209 - -234 0.11 – 0.12 16 – 34 0.001 – 0.07 0.63 – 0.98 0.03 – 0.76 0.05 – 0.10 0.006 – 0.01 0.031 – 0.05 98.9 - 99.9
oxidation step to remove the excess of H2S as elemental sulphur. In Table 3 are presented the data about analyzed microbial content of the liquid phase of anaerobic bioreactor. The dominants in a formed mixed culture are sulphate-reducing bacteria. They are using lactate as a carbon and energy source. The concentrations of all investigated groups of
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Revista Minelor - Mining Revue no. 3 / 2012
microorganisms are higher with orders in the microbial biofilm. The precipitation of metal ions as metal sulphides from solution is dependent on the availability of HS- ions in solution, which in turn is pH-dependent. Due to microbial generated bicarbonate ions, the pH of the treated wastewater remains relatively unchanged between 7.46 and 7.69. Under these conditions precipitation of metal ions as metal sulphides is enhanced. The results obtained for composition of metal sulphide sludge are shown in Table 4.
fixed bed bioreactor and effluent. The metal sulfides with low solubility products tend to initially form very small particles and later on small crystals in the solution. Remoundaki et al. (2008) reported the formation of mainly amorphous Zn and Fe sulfides in a sulphate reducing fixed-bed reactor, which are not suitable for the recovery of metals. Other authors (Kaksonen et al. 2003, Bijmans et al. 2009) reported the formation of crystalline sphalerite, pyrite and wurtzite for fluidized-bed reactors and gas-lift reactors.
Table 3 Number of main physiological groups of microorganisms in effluent from fixed bed anaerobic bioreactor Physiological group Anaerobic heterotrophic bacteria Fermenting sugars bacteria with gas production Sulphate-reducing bacteria, using lactate
Number, cells/ml 2,5.106 5,0.105 1,3.107
Table 4 The composition of the sludge of the settler Element Cu Fe Zn Ni Cd Co S
Weight, % 41.00 2.24 4.09 2.30 2.14 0.50 26.50
Based on theoretical stoichiometry of relative reactions between heavy metals and HS- ions, the metal precipitates in sludge are metal sulphides. The metal precipitates were analysed as XRD diagrams in order to verify their composition (Figure 2). XRD diagrams of metal precipitates revealed that the precipitates were predominantly CuS, FeS, ZnS, NiS, CoS2 CdS, and CuFeS2. Steed et al. (2000) reported that in addition to sulphides, metals precipitate as hydroxides or carbonates. XRD analysis of the precipitates (figure 2) demonstrated also the presence of insigni cant amounts of carbonate phases (CuCO3, FeCO3, ZnCO3 and CdCO3) Hydroxide and carbonate precipitation is of concern especially when the pH of the wastewater was 6.2–7.5, wastewater was treated with filters containing alkaline materials or when the pH of the treatment process was adjusted with e.g. NaOH, NH4OH or Na2CO3 containing buffers (Kaksonen et al. 2003). The conditions in the settler (pH between 7.46 and 7.69) allowed the precipitation of insigni cant amounts of metal ions as metal carbonates. The amount of fine particles leave the setter due to the high recycle ratio and it was detected in
Fig. 2 X-ray diffractogram of metal sulphide sludge 4. Conclusions The following conclusions can be drawn from this study: The mixed culture of sulphate reducing bacteria showed high resistance to ionic forms of Fe, Co, Zn, Cu. and Ni. Cadmium has highest inhibitory effect on sulphate reducing bacteria. A high removal rate of heavy metals Cu – 200 mg/l, Fe – 20 mg/l, Zn – 20 mg/l, Ni – 10 mg/l, Cd – 10 mg/l and Co – 10 mg/l was achieved by fixed bed anaerobic bioreactor when lactate was used as sole source of carbon and energy and the initial COD/SO42- ratio was around 2.7. The produced alkalinity neutralized the wastewater from pH 2.50 – 2.73, resulting in effluent pH of 7.46 – 7.69. References 1. Bayrakdar A., Sahinkaya E. , Gungor M., Uyanik S., Atasoy A Performance of sulfidogenic anaerobic baffled reactor (ABR) treating acidic and zinc-containing wastewater, Bioresource Technology 100 4354–4360., 2009. 2. Bratkova S., Angelov A., Nikolova K., Babanova E. Removal of Cu(II) ions from waters using biogenic hydrogen sulphide, Proceedings of the XI-th national conference with international participation of the open and underwater mining of minerals, Varna, Bulgaria, 19-23 june 2011.
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3. Buisman C., Huisman J., Dijkman H, Bijmans M. Trends in application of industrial sulphate reduction for sulphur end metal recycling. Proceedings of European Metallurgical Conference, 11-14 June 2001, Düsseldorf, Germany vol 2:383-387, 2007. 4. Cabrera G., Perez R., Gomez J., Abalos A., Cantero D. Toxic effects of dissolved heavy metals on Desulfovibrio vulgaris and Desulfovibrio sp. Strains, Journal of Hazardous Materials A135 (2006) 40–46, 2006. 5. Cao J., Zhang G., Mao Z., Fang Z., Yang C. Precipitation of valuable metals from bioleaching solution by biogenic sulfides, Minerals Engineering 22 (2009) 289–295 6. Costa,M.C., Martins,M., Jesus, C., Duarte, J.C. Treatment of acidmine drainage by sulphate-reducing bacteria using low cost matrices. Water Air Soil Poll. 189,149–162, 2007 7. Hao, O.J. Metal effects on sulfur cycle bacteria and metal removal by sulfate reducing bacteria. In: Lens, P.N.L. and Hulshoff Pol, L. (eds.) Environmental technologies to treat sulfur pollution, Principles and engineering. IWA Puplishing, London. Pp.393-414, 2000. 8. Hoa, T.T.H., Liamleam,W., Annachhatre, A.P. Lead removal through biological sulfate reduction process. Bioresour. Technol. 98, 2538–2548, 2007. 9. Kaksonen, H., Franzmann, P.D., Puhakka, J.A.. Effects of hydraulic retention time and sulfide toxicity on ethanol and acetate oxidation in sulfate-reducing metalprecipitating fluidized-bed reactor. Biotechnol. Bioeng. 86, 332–343, 2004 10. Kaksonen, A.H., Puhakka, J.A. Sulfate reduction based bioprocesses for the treatment of acid mine drainage and the recovery of metals. Eng. Life Sci. 7, 541–564, 2007. 11. Kaksonen, A.H., Riekkola-Vanhanen, M.L., Puhakka, J.A Optimization of metal sulphide precipitation in fluidizedbed treatment of acidic wastewater. Water Res. 37, 255– 266, 2003. 12. Liamleam, W., Annachhatre, A.P. Electron donors for biological sulfate reduction. Biotechnol. Adv. 25, 452–463, 2007.
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13. Medircio S., Leao V., Teixeira M. Specific growth rate of sulfate reducing bacteria in the presence of manganese and cadmium. Journal of Hazardous Materials 143 593–596, 2007. 14. Nagpal, S., Chuichulcherm, S., Peeva, L., Livingston, A. Microbial sulfate-reduction in a liquid-solid fluidized bed reactor. Biotechnol. Bioeng. 70, 370–380, 2000. 15. Nevatalo L., Mäkinen A., Kaksonen A., Puhakka J. Biological hydrogen sulfide production in an ethanol– lactate fed fluidized-bed bioreactor, Bioresource Technology 101 276–284, 2000. 16. Remoundaki ., Kousi P.,Joulian C., Battaglia-Brunet F., Hatzikioseyian A.,Tsezos M. Characterization, morphology and composition of biofilm and precipitates from a sulphate-reducing fixedbed reactor Journal of Hazardous Materials 153, 514–524, 2008. 17. Steed, V., Suidan, M., Gupta, M., Miyahara, T., Acheson, C., Sayles, G. Development of a sulfate-reducing biological process to remove heavy metals from acid mine drainage. Water Environment Research 72: 530-535, 2000 18. Utgikar, V.P., Harmon, S.M., Chaudhary, N., Tabak, H.H., Govind, R., Haines, J.R. Inhibition of sulfate-reducing bacteria by metal sufide formation in bioremediation of acid mine drainage. Environ. Toxicol. 17, 40–48, 2002 19. Veeken, A.H.M., Akoto, L., Hulshoff Pol, L.W., Weijma, J. Control of the sulphide concentration for optimal zinc removal by sulphide precipitation in a continuously stirred tank reactor. Water Res. 37, 3709–3717, 2003 20. Velasco A., Ram rez M., Volke-Sepulveda T., Gonzalez-Sanchez A., Revah S. Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation, Journal of Hazardous Materials 151, 407–413, 2008 21. Vossoughi, M., Shaketi, M., Alemzadeh, I. Performance of anaerobic baffled reactor treating synthetic wastewater influenced by decreasing COD/SO42- ratios. Chem. Eng. Process 42, 811–816, 2003
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THE STABILITY OF THE HEAP BRANCH II COROIE TI - E.P.C.V.J. VULCAN Cristina IONIC *, Victor ARAD**
Abstract Research on the stability of the heap have begun by setting the factors that contributes to instability, after which the steady state analysis of talus using several methods of calculation, and in the end, were designed some steps to stabilise tripping or slipping. The stability analysis was performed using the dedicated geotechnical software Slide. After the stability analyses it can be concluded that the heap Coroie ti Branch II is stable when the sterile material is deposited under normal conditions of humidity and may become unstable in terms of increasing the humidity up to saturation, what it is, however, unlikely, considering the large capacity of dispose of water by the stockpiled rocks. Keywords: heap, stability, resizing 1. General considerations Landslides are geo-dynamic occurrences altering the relief, with a generally slow and periodically character, which restores the natural balance of mountainsides and slopes. When they occur unexpectedly, depending on their location, landslides may result in loss of life and substantial material damage. The slopes sliding occurrences take place, usually, when the local balance or assembly of forces that stress them is destroyed and the internal solidity forces that oppose sliding is destroyed, under the effect of internal and external factors, natural or artificial. 2. Stability analysis In terms of morphology area deployment of branch RII Coroie ti, the surface stockpiled is an irregular surface, represented by the hillsides in the area. Their inclination favors the occurrence of slides on the surfaces of contact heap – base terrain when accordance between the inclination of mountainsides and expansion of heap exists and ensures stability when declivity is reversed – just like the west slope of the pillars P2 and P3. _____________________________ * Eng.Ph.D stud. University of Petro ani ** Prof.eng.Ph.D University of Petro ani
For the first case, with increasing declivity of the base terrain the tangential component of the sliding forces is amplifyed and the stability reserve is reduced. In such cases the literature recommends the build up in stairs or scabbing when the declivityes of the base terrain is above 10°. In case of branch RII, the occurrences that could change the ratio between the forces of resistance and the active sliding forces of the slopes by impairment appear on the North side because of the presence of Priboi gill. It’s considered that today, because of the absence of expanding developments of the heap in this area, the erosion activity of the gill is very depressed. The other erosion processes as gap formation due to drip waters, although they are present, they can’t change into proper slides themselves. In case of the heap bellow branch RII we can see overloads of the slopes by rocks deposit and increase of geometrical elements. The bigger the values, the frequent the processes of deformation and instability can be. In case of heap bellow branch RII, the slopes angles generally correspond to the natural slopes angles of rocks and they depend on the granulometric property and the index of compaction of material. According to the surface mapping for the transversal and longitudinal sections, the slopes angles are between 28-33° and can reach 40-44° and the heights of the slopes change because of the morphology of the terrain and the configuration of the heap, values being registered of 21-30 m, reaching 50-69 m. Because the values of those parameters are quite large new process of instability can appear that would affect the surrounding areas therefore certain geotechnical measures would assert. To analyze the stability of slopes, Slide has been used, a software specialized in geotechnical analyze. Slide analyses the stability of natural and artificial slopes by any geometry, both in statically conditions, seismically and by analyzing the presence of water in the pores of the dumped material or on the slope of the heap. The first stage in the usage of Slide is entering the geometrical and geotechnical elements that characterize the slope, then the definition of the slide surfaces.
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The software automatically calculates the stability factors, using for this the Fellenius, Janbu and Bishop methods. Finally, the critical sliding surface is determined, which coincides to the minimum value of the stability index.
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The software analyses the stability of slopes and natural mountainsides with complex geometry, homogeneous and heterogeneous, considering the hydrostatical level both in normally static conditions and in the influence of seismically shocks.
Fig. 1 Transversal section T3-T3 –eastern slope, natural humidity
Fig. 2 Longitudinal section L1-L1 –northern slope, natural humidity Table 1. Stability analysis for cilindrico-circular sliding surfaces Section T1-T1 western slope T1-T1 eastern slope T2-T2 western slope T2-T2 eastern slope T3-T3 western slope T3-T3 eastern slope T4-T4 western slope T4-T4 eastern slope L1-L1 northern slope
Maximum heigth H (m) 43,157 42,845 41,707 41,756 40,501 39,016 21,927 21,927 68,500
Angle of slope (degrees) 35 33 28 41 33 44 32 42 30
Methods used Bishop Fellenius 2,063 1,850 1,922 1,831 1,464 1,346 2,180 2,000 1,650 1,525 1,398 2,322 2,807 2,620 1,783 1,622 1,538 1,410
Janbu 1,822 1,797 1,326 1,968 1,506 1,298 2,548 1,599 1,392
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Using the Fellenius method, the software automatically calculates the effective weight of sections, considering the real hydrostatical level. Janbu’s method used by the software is a simplified version, extrapolated for the situations in which the slope has more layers with different physical-mechanical properties and it’s based on the calculation of the effort to lump meaning the hypothesis of multiple section calculation. First, the software determines the value of the stability index using Fellenius’s method and then it uses the calculated value as a starting point for the iterative cycle. Considering that we can analyze using different software the slopes made of multiple layers with different geotechnical parameters, those software determine the weighted average of the coefficient Cf. From the table we can observe that the smallest values are given by Janbu’s method. We haven’t considered the values of the physical parameters, the cohesion and the internal angle of friction to the moisture saturation, because, generally, Jiu Vallye’s heaps (because of the material’s granulometry and the permeability slightly raised) assure a good drainage of the waters from rain. For all of the sections analyzed, conditioned by the physical-mechanical characteristics of the material used in natural humidity, higher than one values for the stability index have been calculated, over 1.3, recommended by the Technical prescriptions concerning the design, execution and conservation of heaps. At the limit of stability is the eastern slope from the section T3-T3 (Fs < 1,3), the others being slopes that become instable only in the presence of a material with the humidity on its saturation, as a result of higher geometrically elements (height and tilt) that are less favorable. Based on those presented, we can conclude that branch RII of Coroie ti heap is stable when the dumped material is stored on normal humidity conditions and risks to become unstable when the humidity raises to the saturation limit, which is, still unlikely, considering the large capacity of water disposal that dumped rock have. One of the reasons of sliding could be the failure to regard the geometrical elements of build up in stairs, especially the tilt of slopes, as a lack of slope maintenance and the development of intermediate berms. 3. Resizing the geometrical elements of slopes Based on the results of stability analysis made for several slopes with different combinations of height and slope angle, for the result of sizing calculation and the technological characteristics of
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dumping it’s recommended to ensure a geometry of the heap so that the height of the slopes are top 25 m and the angle of the slopes is maximum 35°. Considering the existent slides on the eastern slope from this area, stable by this time and the current configuration of the terrain, is proposed the re-geometrization by developing intermediate berms at height +665 and +680 that would build the slope in stairs with a maximum height of 15 m that would meet the stability requirement of slopes even if the humidity of rocks is at the saturation limit. By this re-geometrization of the eastern slope, at the northern limit of the heap, is assured, on one hand, the increase of dumping capacity on the heap and on the other hand, mining redevelopment and biologically recultivation. 4. Measures to assure the stability of the heap and protection of the environment Considering the characteristics of the base terrain, the shape of the heap and the factors that influence the stability, the analysis made for the slopes of branch RII of Coroie ti heap, was made thinking that most likely the slide occurs on cylindrical-circular surface, the sliding process risking to affect some areas of the eastern slopes, respectively the western side of the heap. Instability problems can occur under the buildup of rock humidity, on the saturation limit, by worsening the resistance characteristics of the dumped material. Sliding occurrences can appear near pylons P1, P3 and P4, if the humidity of the dumped sterile reaches the saturation limit, which is unlikely, considering the configuration of the heap and the bordering areas that favor the flow of water, the possibility of infiltration and drain of water because of high permeability of the dumped rocks. To ensure a greater stability of the dumped volume of sterile in the last three years, a regeometrization is recommended so that the angle of the slope is decreased to 30°, renouncing the actual 44.5°. Therefore is recommended a process of rearranging from top to bottom using a bulldozer. Rearranging from top to bottom consists in displacing the rocks from the top and requires bigger surfaces of terrain to store the entire volume of rocks initially stored and can be done any time the required surfaces are available. To do so, excavator type draglima, type shovel with large working parameters can be used, but the most used is the bulldozer. According to the angle that is used to rearrange the slope we can calculate the volume of material that needs displacement and the time required to achieve.
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To protect the environmental factors from the areas affected by the presence of heaps a series of measures need to take place, among the mentions: a. Measures to prevent the pollution of ground waters and surface waters by harmful substances that could drain in Priboi gill. Because the extracted material doesn’t contain harmful substances, there’s no water pollution with this kind of substances. b. Measures to avoid carrying the dumped material by running water. This means bed planning work of Priboi gill and the avoidance of carrying of dumped material by the drip waters from the slopes by directing them to the sides, foresting and grassing marginal slopes. c. Measures to avoid carrying the dust particles by predominant winds. This is not applicable here, although the heap is done by aggradation, because the granulation of the dumped material is large. Sources of dust are created by disintegration and alteration of rocks from the slopes and this is the reason why grassing the slopes is recommended in the areas where dumping is no longer achieved. 5. Conclusions The heap U.P. Coroie ti branch RII, was classed 4.2 by the nature of objectives from the area of influence and degree of stability, according to “Technical prescriptions regarding the design, the execution and the conservation of heaps”, 5-th appendix from “Specific rules of work protection for the coal mines, shales and bituminous sands”, 1997-th edition, being considered a relatively stable heap that could move dangerously if certain factors are met (relief condition, meteorological condition, accumulation of water in upstream, water infiltration at the base and so on) without
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constructions and sporadic access of persons in the area. Is made in a single step with heights between 10y12 m and 47y50 m, according to the terrain configuration and the deposit geometry. The heap bellow branch RII has a regular geometry except the northern part from pillars P4 and P5 where slides occurred in 1999 and pillars P2 and P3 in 2006. The upper platform elevations varies between +714.04 m in the southern extremity, +681.85 m in the northern extremity, and it’s width between 60y115 m. Based on those presented, we can conclude that branch RII of heap Coroie ti is stable when the dumped sterile material is in normal natural humidity conditions and risks to become unstable when the humidity increases to the saturation limit, which is, unlikely, considering the large capacity of water disposal by the dumped rocks. One of the risking sliding reasons may be the failure to regard the geometrical elements of build up in stairs, especially the tilt of slopes, as a lack of slope maintenance and the development of intermediate berms. References 1. Laz r M., Dumitrescu I. Anthropogenic impact on the environment, Editura Universitas, Petro ani, 2006 2. Laz r M. Ecological rehabilitation, Editura Universitas, Petro ani, 2001 3. Rotunjanu I. Stability of slides and slopes, Editura Infomin, Deva, 2005
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PREPARATION AND DEVELOPMENT OF GEOTECHNICAL MAP OF ALBA IULIA TOWN, ALBA DISTRICT Ecaterina BALANEANU*, Victor ARAD**, Letitia Susana ARAD***, Flavius BALANEANU* Abstract The continuous change of the legislation dealing with the geotechnical domain, the orientation toward the European legislation through EUROCODES and the endless intervention of man in the given landscape, determines a permanent need for updating the maps, no matter their type. The ecology and environmental protection together with the terrain structure in depth must be correlated all the time so as to allow a positive cohabitation of all citizens. In order to draw up and make a geotechnical map, it is compulsory to take into consideration several elements that will work together in the process of reaching the final result. The final result must grant the requests and the complex needs of all parts involved-including the environmental requirements. The geotechnical dividing of the Alba Iulia town will be made according to the three existent morphological elements, id est: the meadow area-of the Mures River and the common meadow of the Mures River and the Ampoi River relating to the old town, the terrace area of the Mures Riverwhere the fortress is located together with all its contiguous constructions; and thirdly, the deluvial sediments area-identified in the western part of the town where there are no building regulations set. The present work wants to draw up and make a geotechnical map that presents the foundation layers and the geotechnical framing of each and every area in Alba Iulia town, Alba county. Thus, there will be a summarization of the geotechnical data that can be used as a starting point when carrying the geotechnical studies for every planned objective considered alone. Keywords: ecology, geotechnics, terrain structure, geotechnical risk, geotechnical map
The present work will be structured according to each morphological element encountered in the geomorphology of Alba Iulia town.For each element there will be considered the following aspects: location, stratification, recommended foundation terrain, recomended basic pressure and placing the element in the appropriate geotechnical category following the present regulations. 2. The geomorphologic categorization
Fig. 1 The geomorphological categorization of Alba Iulia town From a geomorphological point of view, Alba Iulia town is to be related to the chute of the Mures River. This develops alongside the Mures River and comprises landforms dug and shaped by the river course or meandered. In the course of time, the shape of its river course changed producing beaches and eroding shores. These iterative phenomena led to the change and migration of the river course resulting in sediments of alluviations on one side and erosion in the opposite direction.
1. Introduction The present work intends to make a geotechnical map of Alba Iulia town so as to exist a database sufficient to become a starting point for making the geotechnical study for every objective that is to be built. _____________________________ * Eng.Ph.D stud. University of Petro ani ** Prof.eng.Ph.D University of Petro ani *** Assoc.prof.eng.Ph.D University of Petro ani Fig. 2 The meandered course of the Mures River
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The Thedeluvial deluvial sediments area area sediments The terrace The terrace area area
The meadow area The meadow area
Fig. 3 The geotechnical map of Alba Iulia town The paper refers strictly to the built-up area of the Alba Iulia town without considering the localities that are part of it. We encounter the following land levels: - Zone I – the meadow area of the Mures River and the common meadow of the Mures River together with the Ampoi River ; - Zone II – the terrace area of the Mures Riverwhere the fortress is located together with all its contiguous constructions; - Zone III - the deluvial sediments area-identified in the western part of the town where there are no building regulations set. Location The meadow area is divided into two sections related to the river courses that cross it.
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of the characteristics related to the foundation layers of the existing buildings .[1] At the same time, the migration of the underground water toward the surface through coarse and mixed layers leads to degradation- the pollution of the environment and human habitat due to the direct link between the river courses and the the level of the underground water .[1] Thus, we have: the meadow area of the Mures River and the common meadow of the Mures River together with the Ampoi River . Zone I – the meadow area The meadow area of the Mures River This area comprises the “downtown”-named like this because the first houses were built here. The area is located in the newer neighbourhoods of the town, named after the Ampoi River. The floods of 1970 caused significant damages to the buildings and affected the entire town of that time. The dams built alongside the Mures River and the climate change of the past few years have led to the stabilization of the underground water of this side of the town. The common meadow area of the Mures River together with the Ampoi River The common meadow area of the Mures River together with the Ampoi River is bordered by the watercourse of the two rivers. The Watercourse of the Ampoi River does not present a significant flow but enough to maintain the level of the underground water constant in that perimeter.
Fig. 4 The meadow area of the Mures River The meadow area has been flooded numerous times, the old buildings have been weakened by the water penetrating the walls. For this area there is a need to take also into account the Geotechnics of the Environment because water, as an environmental factor, concurred to the deterioration
Fig. 5 The common meadow area of the Mures River together with the Ampoi River Stratification In all the undergone drillings the stratification presents the pattern of the meadow areas : - Vegetative layer or filling;
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- The fine Complex : Brown silty sand; - The mixed Complexul:Silty sand with gravel; - The coarse Complex: Gravel with sand. 120
vegetative soil or filling fine clay mixed clay coarse clay
0
Fig. 6 The distribution of stratification in the meadow area [2][3][6][7] In all the layers mentioned above there are insertions of organic materials presenting different thickness. These insertions must be identified and clearly defined because it is not allowed to found on them. They must be taken out and then found deeper entering 0.20 m in the good foundation terrain existing in that location. The undergorund water appears at a depth of 2.00-2.50 m from the natural terrain to the contact between the fine Complex and the mixed one. To its superior part, it becomes flooded. The variation of the underground water level are closely connected to the flow amountof the surface water in the area and the rainfall. Thus, it is taken into account an increase with +50 m from the altitude where it is encountered. The recommended foundation terrain According to the Regulatory document INDICATIV NP 074 - 2007[4] , it is recommended to consider the following foundation layers:
¾ The fine Complex: Brown silty sand- without taking further measures, ¾ The mixed Complex: Silty sand with gravelwith extra measures to support diggings accoringly and ¾ The coarse Complex: Gravel with sand-with both extra measures to support diggings accordingly and measures related to dewatering. It is not allowed to found on vegetative soil and local fillings. Also, it is forbidden to cast concrete if coming across muddy ground or with organic material. These will be dug out and the diggings deepened. The recommended basic pressure It is allegedly considered that the layers presented below are clean and do not contain muddy intercalations. The calculating values of the conventional pressure are determined according to Stas 3300/2-85 [5] from the natural terrain level. For each layer, we will have the following values: ¾ The fine Complex: Brown silty sand : Pconv =220 KPa ¾ The mixed Complex: Silty sand with gravel: Pconv =250 KPa ¾ The coarse Complex: Gravel with sand: Pconv =350 KPa Geotechnical categorization According to the Regulatory document INDICATIV NP 074-2007 [4] the foundation terrain will be placed into the adequate geotechnical category, thus resulting the geotechnical risk.
Table 1 Geotechnical categorization [Table A3][2][4] Difficult terrains Good terrains Medium terrains 6 pts 2 pts 3 pts Underground water No dewatering With normal dewatering With exceptional dewatering 1 pt. 2 pts 4 pts Particularly exceptional The building Reduced Normal 5 pts classification according 2 pts 3 pts to the importance class Vicinity Major risk No risks Moderate risk 4 pts 1 pt. 3 pts Overall score = 7 - 10
Terrain conditions
According to the table above, the geotechnical risk is reduced and the geotechnical category is 1 – 2 . Table 2 Geotechnical risk [Table A4][2][4] Nr.crt Geotechnical risk Type Score limits 1 Reduced 6…….9 2 Moderate 10………14 3 Major 15..……..21
Geotechnical category 1 2 3
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Zone II – the terrace area Location The terrace area of the Mures River comprises the fortress with all the contiguous constructions- located in the centre of Alba Iulia town. The area gathers all the terraces of the Mures River. This area has undergone the most intense town planning. In the plans dealing with the enlargement of the town it was necessary to join the “downtown” to the fortress lying above. As a result of consulting the specialists of that period, it was stated that fillings resulting were the best solution. Thus, all the fillings resulting from constructions were stored in this zone. The thickness of the fillings is big. In some areas it is even as thick as 3.00 m, the blocks of flats built afterwards having wide foundations in order to resist.
35 vegetative soil or filling fine clay
120
mixed clay
The terrace area
coarse clay
0
Fig. 8 The distribution of the stratification in the terrace area [2][3][6][7] The tickness of the filling is evident. The exact thickness of the fillings must be known because the process of founding on them takes place under special conditions. The underground water appears at a depth of – 8.00 – 10.00 m from the natural terrain to the contact between the fine Complex and the mixed one. To its superior part, the mixed Complex is moist whereas to its inferior part it becomes flooded. Of course, it is necessary to mention the streams in the area. There are streams even in the ditches existing alongside the fortress. The recommended foundation terrain According to the Regulatory document INDICATIV NP 074-2007 [4] , the following foundation layer is recommended: The fine Complex: Brown silty clay – without taking further measure. The mixed Complex: Silty sand with gravel, and the coarse one: Gravel with sand appear at great depths. It is not considered a foundation layer except for objectives requiring great depths. Since the thickness of the filling layers is big and there are already finished constructions, this may be taken as a foundation layer as well.
Fig. 7 The terrace area Stratification The stratification encountered is as follows: - Filling layer; - The fine Complex: Brown silty clay - The mixed Complex: Silty sand with gravel - The coarse Complex: Gravel with sand.
The recommended basic pressure For the fine Complex: Brown silty clay; the values of the conventional pressure are to be considered. This is calculated according to Stas 3300/2-85 from the level of the natural terrain [5]. We will have the following values: ¾ The fine Complex: Brown silty clay: Pconv =240 KPa ¾ Filling – older than 25 years but not compacted under control: Pconv =180 KPa Geotechnical categorization According to the Regulatory document INDICATIV NP 074-2007 [4] the foundation terrain will be placed into the adequate geotechnical category, thus resulting the geotechnical risk.
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Table 3 Geotechnical categorization [Table A3] [2][4] Difficult terrains Good terrains Medium terrains 6 pts 2 pts 3 pts Underground water With exceptional No dewatering With normal dewatering 1 pt. dewatering 4 pts 2 pts Particularly exceptional The building Reduced Normal 5 pts classification according 2 pts 3 pts to the importance class Vicinity Major risk No risks Moderate risk 4 pts 1 pt. 3 pts Overall score = 7 - 9 Terrain conditions
According to the table above the geotechnical risk is reduced and the geotechnical category is 1. Nr.crt 1 2 3
Table 4 Geotechnical risk [Table A4] [2][4] Geotechnical risk Type Score limits Reduced 6…….9 Moderate 10………14 Major 15..……..21
Geotechnical category 1 2 3
Zone III – the deluvial accumulations area Location Zone III presenting deluvial accumulations can be identified in the western part of Alba Iulia town where there are no building regulations yet. These areas are proposed to be inserted within the buildup zone, currently being the zone for building holiday cottages. The vegetative soil is thick – aproximately 1.00 or even 1.50 m. The presence of tree roots takes its toll. For this area as distinctiveness appears the possibility to control the process of building in the area. Even though in the I-st and II-nd geotechnical zones it is not possible to impose a regulation, discipline concerning building, the III-rd zone is ideal for this thing.
The deluvial accumulations area
Stratification The stratification encountered is as follows: - Layer of vegetative soil with thick roots; - The mixed Complex: Silty sand with gravel - The fine Complex: Clayey marly silt. The recommended foundation terrain According to the Regulatory document INDICATIV NP 074-2007 [4], the following foundation layer is recommended : The mixed Complex: Silty sand with gravel; in this case, it is of deluvial origin and has high percentage of gravel. Its deluvial origin resulting from erosion and hard material transportation makes it suitable for becoming a foundation layer.
Fig. 9 The distribution of stratification in the deluvial accumulations area 120
vegetative soil with thick roots mixed clay fine clay
0
Fig. 10 The distribution of stratification in the deluvial accumulations area [2][3][6][7]
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The recommended basic pressure For the mixed Complex: Silty sand with gravel; the values of the conventional pressure are to be considered. This is calculated according to Stas 3300/2-85 from the level of the natural terrain [5]. We will have the following values:
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¾ The mixed Complex: silty sand with gravel: Pconv =250 KPa Geotechnical categorization According to the Regulatory document INDICATIV NP 074-2007 [4] the foundation terrain will be placed into the adequate geotechnical category, thus resulting the geotechnical risk.
Table 3 Geotechnical categorization [Table A3] [2][4] Difficult terrains Good terrains Medium terrain 6 pts 2 pts 3 pts With exceptional Underground water No dewatering With normal dewatering 1 pt. dewatering 4 pts 2 pts Particularly exceptional The building Reduced Normal 5 pts classification according 2 pct 3 pts to the importance class Vicinity Major risk No risks Moderate risk 4 pts 1 pct 3 pts Overall score = 7 Terrain conditions
According to the table above the geotechnical risk is reduced and the geotechnical category is 1. Nr.crt 1 2 3
Table 4 Geotechnical risk [Table A4] [2][4] Geotechnical risk Geotechnical category Type Score limits Reduced 6…….9 1 Moderate 10………14 2 Major 15..……..21 3
3. Conclusions In the present work there has been crafted a geotechnical map of Alba Iulia town based on the data related to the stratification determined by drillings and the morphology of the terrain in Alba Iulia. The database that resulted is sufficient to become a starting point for making the geotechnical studies for every objective that is to be built. Of course, the data put together are not comprehensive enough to replace a geotechnical study but they offer the possibility to become aware of the nature of the terrain at the desired depth. Furthermore, the recommended basic pressure and geotechnical categorization may be used according to the existing regulations. The geotechnical categorization is made at the initial level and asks for special attention to: the terrain conditions, the possibility of emergence of underground water, the class of the constructionand especially to the the vicinity. The vicinity is a very important factor in the context of determining the geotechnical risk for the future building.
References 1. Arad, S., Arad, V., Chindris, G. Environmental geotechnics, Polidava Publishing house, Deva, 2000; 2. Arad, V., Bogdan, I. Geotechnics and foundations, Solness Publishing house, Timi oara, 2001; 3. Arad, V. Rock mechanics, Didactic and Pedagogic Publishing house, Bucure ti, 2004; 4. Regulatory document NP 074/2007 regarding the elaboration and verification of Geotechnical studies from 08/05/2007 Published in the Official Journal, Part I no. 381 from 06/06/2007; 5. Stas 3300/2-85 – for determining the basic pressurei.e. conventional, calculated according to Appendix B, for foundations with B=1.00 m and foundation depth Df= 2.00 m 6. SR EN ISO – 14688 – 1st – November 2004– The identification and classification of soils. Part 1: Identification and description ; 7. SR EN ISO – 14688 – 2nd – September 2005 – The identification and classification of soils. Part 2: Principles for classification (from a granulometric perspective). 8. www.google.ro 9. http://alba-iulia-ab.pe-harta.ro/
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Revista Minelor - Mining Revue no. 3 / 2012
A CONTEXTUAL ANALYSIS OF OCCUPATIONAL ACCIDENTS OCCURRED IN VALEA JIULUI COLLIERIES DURING THE LAST FOUR DECADES Roland Iosif MORARU*, Gabriel Bujor B BU *
Abstract An analysis of accident records provides a useful means for identifying patterns in the incidence of accidents in professional populations. Despite all precautions, underground coal mining is one of the dangerous industries leading to fatal occupational accidents. Accidents are complicated events to which many factors effect on their causation and preventing them is only possible by analyses of the events occurred in past and by proper interpretation of the statistical results. This paper synthesizes the analysis of accidents occurred in Valea Jiului collieries from 1972 to 2010. It is found that methane remains the main concern for the future, despite a favourable evolution trend in overall fatality rate. At last, it brought forward some conclusions and prospects for the improvement of safety levels in the collieries in Valea Jiului. Keywords: statistics, events, methane, explosion, risk, occupational safety and health.
x the need for rational use of methane drainage technology [8]. Although the main reason for extracting methane from coal deposits continue to be the methane emissions reduction from mining operations, an important incentive was draining the gas and provide a source of fuel and the need to reduce emissions of greenhouse gases. Black coal mining in Jiu Valley coal basin is being carried out in difficult geological-mining conditions, which creates many hazards to health and safety of underground personnel. The major mining risk factors are including the explosions of methane-air mixtures, which too often have been causes of mine disasters [6]. Practical materialization of scientific principles to prevent methane explosions has significantly contributed over time to the decrease of the explosion risk in coal mines [7, 11]. However, despite numerous scientific and technological achievements in this field, explosions continue to occur, remaining a potential threat to life and health of underground workers, contributing to generate considerable costs associated with fighting and rescue actions, asset damages, reserves immobilization and compensation granted.
1. Introduction Methane, entity present in worldwide coal mining industry, has represented along time the main risk factor and subject of major concern in research and ensuring higher safety levels [1, 2, 9]. Worldwide, thorough research aimed at deeper knowledge about the occurrence and prevention of hazards caused by methane gas, shows that no price is too high to reward achievements in possession and control of safety in underground environment. Methane was continuously a maximum point of care in study and analysis for three main reasons, namely: x methane is a natural product and appears frequently in underground excavations; x methane is the cause of several accidents with catastrophic consequences, which resulted in casualties, more than other risk factors in the history of mining [3]; _____________________________ * Assoc.prof.eng.Ph.D University of Petro ani
2. Nature of methane gas impact on health and safety of underground workers Methane associated with coal deposits in the Jiu Valley coal basin has been a constant concern, over time, both in terms of safety and health of workers, deposit, equipment and machinery used in underground protection and in terms of impact on the atmosphere. Today, in the mines within the Jiu Valley basin are applied mining methods that have in common the downward removal of thick coal seams in slices, namely seam 3, with mining pressure release by the total overthrow of rocks [4]. In the specific case of method the mining method with undermined coal bank, the fragmentation and crumbling of rock massif is developed on a much larger area, creating the occurrence of exploitation gaps and remainder coal quantities in the caved goaf [14]. In this case, through the existing ventilation systems, increases the likelihood of large bodies of methane accumulation, which
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together with coal dust is the main source of potentially explosive atmospheres, with all the related adverse consequences on ensuring safety in underground and proper atmospheric underground environment for a normal course of mining activities. Air inleakage through the space of caved goaf carries oxygen in the goaf and, meanwhile, discharges methane stucked in gaps between collapsed rocks and the heat of oxidation of the material. Depending on the intensity ratio of involved processes, air leakage through the exploited space can lead to self-heating and spontaneous combustion of coal left after mining operations. Research conducted worldwide have shown that the self-heating and spontaneous combustion intensity is even lower with higher methane content in the exploited area, namely in the goaf [10, 12]. In recent years in the Jiu Valley the collective accidents recorded were caused by accumulations of methane in the goaf area. Technical and organizational measures aimed at reducing methane concentrations in underground environment and quantities of methane released into the atmosphere through the main ventilation stations are targeted, directly or implicitly, to the accomplishment of the following objectives: x increased safety and protection of the coal deposit; x ensuring continuity of coal extraction;
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x increased safety of workers in the extraction of coal; x reduction of the reserve immobilization; x reduction of explosive mixture formation risk and reduction of the probability of endogenous fires occurrence; x improving working conditions and safety by decreasing risk factors generated by spontaneous combustion and explosions of methane; x decrease in technical and human accidents due to dynamic phenomena; x the increase of safety and comfort of staff directly involved in the exploitation of coal; x minimizing the environmental impact. 3. Analysis of accident statistics collective mines in the Jiu Valley A statistical record, including collective accidents occurred in the last 33 years in coal mines in the Jiu Valley, presented in Table 1 [16], is particularly indicative of risk associated with explosive mixtures formation while the means to prevent accumulation methane de not have the expected effectiveness [5, 15]. Insufficient dispersion of methane in the ventilation currents, associated with technical failure and/or human error have generated numerous events with extremely severe consequences on human and economic plan.
Table 1. Statistics on collective accidents occurred between 1972-2004 in collieries within Jiu Valley coal basin DATE
OCCURRENCE LOCATION
EVENT CHARACTERIZATION AND EFFECTS
CAUSES OF EVENT’S OCCURRENCE
E.M. Uricani, 02.11.1972 Chamber face, seam. 3, bl. III
Methane explosion x 53 injured (43 mortal,10 ITM); x 2 hours no ventilation in bl. III area.
x x x x
inadequate selected mining technology; inadequate ventilation; faulty AG 25 switch-gear; other organizational causes.
E.M. Petrila 16.01.1980 Frontal face seam 13, panel B3, bl. I
Methane ignition x 7 injured ITM.
x x x
x
failure to respect working technology; inadequate ventilation; other organizational causes. inadequate ventilation; un-proper operation and maintenance of electrical and mechanical equipment; other organizational causes.
x x
inadequate selected mining technology; other organizational causes.
x
error in developing the automated release system of electrical energy; other organizational causes.
E.M. Livezeni, Methane explosion 29.11.1980 Frontal face, seam 5, bl. x 77 injured (53 mortal, 24 VI ITM). E.M. Petrila Coal dust explosion 18.02.1982 Chamber face no. 331, x 29 injured (14 mortal, 15 seam 3, bl. II ITM). E.M. Paro eni Methane explosion Head gallery, level 360, x 24 injured (17 mortal, 7 09.09.1982 frontal face panel ITM). 1,seam 5, bl. V
x x
x x
E.M. Aninoasa Hydrogen explosion 26.06.1985 Frontal face no. 4, seam. x 4 injured mortal. 3, bl. V, level X
x x
inadequate endogenous fire suppression technique, resulting in thermal dissociation of water in hydrogen and oxygen; inadequate ventilation; other organizational causes.
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DATE
21.03.1986
22.03.1986
Revista Minelor - Mining Revue no. 3 / 2012 OCCURRENCE LOCATION
EVENT CHARACTERIZATION AND EFFECTS
CAUSES OF EVENT’S OCCURRENCE x x
x x
inadequately selected blasting technology; failure to reinforcement monograph compliance, respectively lack of old mining area closure; inadequate ventilation; erroneous placement of methane detectors. other organizational causes, respectively granting permitting to access an area with explosive methane concentration. failure to apply correctly the methane and coal dust mitigation systems; use of open fire, without appropriate safety measures; inadequate ventilation; erroneous placement of methane detectors.
Methane ignition
x x
methane concentration build-up; spontaneous combustion development.
Methane ignition
x x
methane concentration build-up; blasting operation.
x
inadequate dam insulation methods and materials.
Methane ignition
x x
methane concentration build-up; electrical short-circuit.
Methane ignition
x x
methane concentration build-up; self-heating process.
x
failure to comply with regulation on breaking oversized blocks technology; other organizational causes. wrong handling of the winch driving the working bridge; other organizational causes.
E.M. Vulcan Seam 7, bl. 0, level 420
Methane explosion x 19 injured (17 mortal, 2 ITM).
E.M. Vulcan Seam 7, bl. 0, level 420
Methane explosion x 17 injured (8 mortal, 9 ITM).
x x x
x
E.M. Vulcan 18.09.1989 Preparation gallery panel 1, seam 5, bl. 0 E.M. Uricani 13-14.11. Frontal face, panel 1, 1991 seam 3 E.M. Paro eni 17.06.1993 Frontal face, seam 5, bl. V E.M. Vulcan 21.06.1993 Mine workings at seam 3, bl. II E.M. Câmpu lui Neag 12.08.1994 Chamber face, seam 17/18, bl. VI.S E.M. Paro eni 30.03.1995 Longwall face, panel 1, seam 5, bl. 0 E.M. Petrila 12.09.1996 SCRI face no. 332, seam 3, bl. II, Level O 25.07.1996
E.M. Petrila Sud Auxiliary Shaft
Methane explosion x 39 injured (29 mortal, 10 ITM).
Carbon monoxyde intoxication
Methane ignition x 5 injured (4 mortal, 1 ITM). Technical accident x 3 injured mortal.
E.M. Uricani Carbon monoxide Gallery of return 08.11.1996 intoxication ventilation seam 8/9, bl. x 5 injured mortal. VI S, level 400 E.M. Vulcan Methane ignition 18.11.1996 SCRI face no. 3, seam 3, x 3 injured (1 mortal, 2 bl. VI ITM).
x
x x x x
failure to comply with the regulation of mining rescue.
x
failure to comply with framework mining method; entering a fire zone, where methane concentrations were above the lower explosion limit; other organizational causes.
x
x
E.M. Petrila Directional opening-out Caving 30.01.1997 on floor of coal seam 4 injured (2 deceased, 2 no. 355 E - 334, seam 3, ITM). bl. II E.M. Dâlja Workings of short-wall 19.05.1997 face no. 2311, seam 3, bl. II
Methane explosion x 12 injured (7deceased, 5 ITM).
x x x x x x x
failure to respect working technology; no correlation of the distance of the front face entries and roads front of top slice; other organizational causes. inadequate ventilation; technical noncompliance with requirements on how to conduct blasting operation; erroneous placement of methane detectors; other organizational causes.
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DATE
OCCURRENCE LOCATION
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EVENT CHARACTERIZATION AND EFFECTS
CAUSES OF EVENT’S OCCURRENCE x
x
changes and improvised electrical equipment enclosure constituting the power switch type electric motor scraper conveyor in cross-entry no. 2, that canceled intrinsic safety protection type of the control circuit of the scraper conveyor; inadequate ventilation.
x x
methane concentration build-up; blasting operation.
x x
x
unfit mining method; technical noncompliance with requirements to prevent and suppress fires and spontaneous combustions; other organizational causes.
x x x
failure to respect working technology; noncompliance with reinforcement monograph; other organizational causes.
x x
x
methane concentration build-up; open flame. lack of knowledge on geological and geomechanical characteristics of the coal and surrounding rock; the presence of numerous excavations around face area, state of intense secondary and variable stresses; the seismic waves generated by explosion loads.
x x
mechanical sparks; failure to respect working technology.
x x x
un-properly performed blasting operations; inadequate ventilation; other organizational causes.
x
methane concentration build-up in insulated area.
x x
x
unfit mining method; technical noncompliance with requirements to prevent and suppress fires and spontaneous combustions; other organizational causes. technical noncompliance with requirements to prevent and suppress fires and spontaneous combustions; other organizational causes.
Methane ignition
x x
methane concentration build-up; blasting operation.
Methane ignition
x x
methane concentration build-up; mechanical friction spark.
Exogenous mine fire
x x
coal behind supporting system; welding operation.
Methane ignition
x x
methane concentration build-up; blasting operation.
E.M. Vulcan Methane ignition 22.07.1997 SCRI face no. 6, seam.3, x 8 injured (2 deceased, 6 bl. IX ITM).
E.M. Dâlja, 28.04.1998 SCRI face no. 331, seam Methane ignition 3, bl. III E.M. Paro eni 29.04.1999 Longwall face panel 2, seam 5, bl.0
Methane explosion x 2 injured ITM.
E.M. Lupeni Longwall face with Caving 02.11.1999 undermined coal bench x 1 injured deceased. panel 3, seam 3, bl. V E.M. Lupeni 17.01.2000 Methane explosion Ventilation raise SABO
x
E.M. Uricani 14.09.2000 Frontal face panel 4, seam 3, bl. III North
E.M. Valea de Brazi 30.09.2000 Frontal face panel 2 S, seam 17-18, bl. VIII
Caving x 2 injured deceased.
Methane ignition x 2 injured ITM.
Methane explosion, with E.M. Vulcan coal dust fines 07.08.2001 SCRI face no. 1-4, seam participation 3, bl. VIII x 7 injured (1 dead, 6 ITM). E.M. B rb teni Methane explosion in Longwall undermined 30.08.2001 closed area with insulating face no. 8 E, seam 3, bl. dams XI, under level 615 Flammable gasses mixture E.M. Vulcan explosion 12.06.2002 SCRI face no. 3, seam 3, x 14 injured (10 deceased, 4 bl. VI ITM).
31.07.2002
22.12.2002 05.07. 2003 18.04.2004 22.05.2004
E.M. Petrila Closed area of face SCRI no. 138, seam 3, bl. 0 E.M. Lonea SCRI face no. 74, seam 3, bl. VII E.M. Lonea SCRI face no. 74, seam 3, bl. VII E.M. Petrila Skip shaft E.M. Uricani Frontal face BS, panel 5, seam 3, bl. III-IV
Flammable gasses mixture explosion x 7 injured (1 deceased, 6 ITM).
x
x x
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Revista Minelor - Mining Revue no. 3 / 2012
Overall analysis of the available statistics allowed highlighting the following issues: x from the total of 35 events classified as collective occupational accidents, 13 are explosions of methane, 13 ignitions of methane, 3 cavings (collapse), 2 carbon monoxide intoxication, an explosion of hydrogen from thermal dissociation of water into hydrogen and oxygen, an explosion of coal dust, a technical fault by incorrect handling winch drive and an exogenous fire; we considered the fact that is unlikely to achieve the minimum explosive concentration of coal dust without prior methane explosion in a state of suspension raising coal dust deposited and - consequently - we considered the event in 18/02/1982 as having the presence of methane as a primary cause; x from the total number of 344 victims of these dynamic phenomena, 239 have died (69,48 %) and the other 105 have suffered temporary work disability (30,52 %); x the 13 methane explosions have resulted in 200 deaths (83,68 % of all deaths) and 87 cases of temporary disability; x the 13 ignitions of methane resulted in 5 deaths (2,09 % of all deaths) and 18 cases of temporary disability;
x the event framed according to the research as â&#x20AC;&#x17E;coal dust explosionâ&#x20AC;? had the effect of 14 human deaths (5,86 % of all deaths) and 15 people who have had varying periods of temporary disability. We can say therefore that 91,63 % of deaths resulting from accidents investigated were due to collective events leading as one of the primary causes accumulation of methane in underground mine openings. To them were added other causes that created the conditions for propagation of accident causation scenarios for the worker staff [13]. 4. Statistical analysis of occupational accidents and safety indicators during 1981-2010 In order to establish the necessary measures and find solutions for increasing occupational safety and health at mines in the National Hardcoal Company, it is required an analysis of accidents evolution and the development of indicators of health and safety at work. Statistically, the situation of events occurrence in the past two decades is shown in Table 2.
Table 2. Occupational injuries and specific indicators evolution in Valea Jiului collieries Year 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Number of occupational injuries ITM Temporary Invalidity Fatalities Work Disability 1002 926 907 826 731 751 948 1377 1625 1368 1337 1489 1646 1669 1506 1940 1413 1136 1131 1278 1338 1165 962 575 319 291 251 220 267 216
14 25 10 23 22 15 18 13 24 5 2 7 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
21 56 17 25 28 45 31 42 77 17 23 23 24 21 16 43 28 6 10 12 18 17 6 7 7 2 1 15 2 1
Total
Ifrequency
Igravity
Iaverage duration
No. acidents/ 1000 t
1037 1007 934 874 781 811 997 1432 1726 1390 1362 1519 1673 1690 1522 1983 1441 1142 1141 1290 1356 1182 968 582 326 293 252 236 269 217
34.5 39.5 35.6 34.5 30.3 27.3 43.9 52.8 51.8 34.7 34.0 36.5 40.5 38.7 37.0 48.0 38.1 49.0 57.2 70.7 75.7 68.5 59.0 39.7 24.5 24.5 21.4 20.5 25.1 23.5
1259.3 1139.3 1176.2 991.4 987.5 752.4 661.0 927.2 947.2 925.7 1042.5 1539.3 1237.6 1243.8 1433.1 1782.8 1543.2 1709.2 2043.0 1399.6 2657.1 2328.3 1966.1 1402.8 1096.4 1261.7 1154.7 1036.1 1356.8 1066.9
32.8 33.6 37.9 33.5 41.3 33.3 26.5 30.7 32.2 26.1 31.9 39.3 32.5 34.7 39.4 35.9 40.6 35.6 36.7 30.2 35.5 34.6 35.4 37.9 45.4 51.7 53.4 52.6 52.1 45.4
0.11 0.10 0.09 0.08 0.07 0.07 0.09 0.13 0.16 0.26 0.28 0.29 0.33 0.30 0.27 0.32 0.28 0.28 0.31 0.34 0.33 0.29 0.28 0.19 0.10 0.11 0.09 0.08 0.12 0.09
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It can be noticed from Table 2 that the worst period in terms of safety and health was recorded from 1988 to 2002. The highest number of accidents occurred in 1996, respectively in 1983, representing over 25 % of the total number of accidents occurred in Romania. The highest number of deaths registered in 1989, 77 fatalities respectively. The accidents frequency index, reported as the number of accidents per thousand workers had the highest value in 2001 being 75.7. In the same year 2001 was recorded also the highest severity index, respectively 2657.1. In year 2000 there were the highest number of occupational injuries reported in the 1000 tons extracted, namely 0.34. From the analysis driven on the evolution of occupational injuries in the last decade, we may find the following: x it significantly decreased the number of accidents involving deaths and disability; x the number of fatalities was influenced by collective accidents occurrence; this is shown from the fact that the number of fatal accidents in years when there were no casualties, is very low, 1-2 fatalities/year; x the reduction, in real terms, of the number and severity of accidents is also highlighted by the evolution of the occupational safety and health indicators; frequency index fell from 75.7 to 23.5, the severity index decreased from 2657.1 to 1066.9, while the index which relates to the production extracted (coal output) fell from 0.33 to 0.09; x although the frequency index fell from 75.7 to 23.5, yet he is the highest in Romania; but if we analyze the frequency and severity index in different industries and activities, we find high severity indexes in fields with low-frequency index; from this analysis we can conclude that in other areas are declared only casualties; the fact that the National Hardcoal Company declares all accidents at work (last year being reported and investigated also the slight injuries) is a positive remark; x the only indicator that increased in the last 10 years is the average duration index from 35.5 to 45.4; this increase indicates that mining workers are having ever lower resilience; the number of days to recover work capacity after an event is becoming bigger; this is mainly due to the increasing average age in the National Hardcoal Company personnel, poor health state of staff, lack of younger workers to perform work requiring high physical intensity work; x between 2000-2010 it increased significantly the number of fatalities at work that can not be classified as occupational injuries: heart attacks, strokes and even suicides, events that occur due to exacerbation of psychosocial risk factors.
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5. Conclusions The statistic analysis of events occurred, accidents, occupational diseases, hazardous incidents, mine fires, self-heating and spontaneous combustion, the analysis of safety indices, nonsafety related costs and loss of production and, especially, the causes that led to these events must underpin any policy setting in the field of occupational health and safety in Valea Jiului collieries. The increase in average age of staff employed in the National Hardcoal Company, the specific conditions of underground activity, the layoffs and employment cessation in mining has led to damage of employees health, this in turn generating the following consequences: x lower resilience and physical recovery capacity; x diminished responsiveness, respectively predisposition to injury; x reduced attention levels and predisposition to stress; x occurrence at higher rate of events likely to be favored by stress causes (cardiovascular accidents, suicide, alcoholism); x emergence of unfitness to perform certain activities; x reduced ability to physical loads; x the emergence in recent years, of new occupational diseases, mostly related to manual handling of loads and noise. Not covering certain jobs or work stations, on which health and safety of employees highly depends, or covering them with workers who do not have the necessary competence or skills or medically they are unfitted, the impossibility to sanction through demotion or dismissal, all these are contextual elements that are conducive to an inadequate safety climate. Since 2006 the focus was legally put on risk assessment to reduce or avoid the risk of major events, especially the methane explosion risk, since the occupational accident statistics and the statistics of non-safety related costs are confirming that these events most influenced the safety status of the National Hardcoal Company. Unfortunately, quite often this fundamental process has a formal character, of exclusive legislative compliance. When undertaking a risk assessment it is of importance to consider the range of hazards proposed by personnel of all disciplines present in the affected area. This may include the mine manager, with whom ultimate responsibility lies, electrical and mechanical engineers, mine safety personnel and workerâ&#x20AC;&#x2122;s representatives. Depending on the perceived severity of the hazard difficulty in fire fighting or the length of the escape
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route, it may also be prudent to consult the Mine Rescue Service, or other emergency service who may attempt to undertake rescue or fire fighting underground. Despite the positively evolving picture painted by the statistics above, the reality may be even worse. A chronic lack of accurate information, at many levels, combined with poor statistical measures probably underestimates the severity of coal mining safety challenges. Closing mines without careful consideration has other negative consequences. A failure to sufficiently fund other aspects of the coal mining industry also contributes to unsafe mining conditions. Fundamentally, solving the coal industry’s problems will require appropriate statistical measures and accurate information. To this end, the use of intensity based measures standards for safety improvement must be adjusted to include quantitybased safety targets. The former, while important, is merely a measure of fatalities relative to coal production and thus an abstract statistic. A reduction in this rate may be offset by higher absolute numbers as a result of increased production levels. By using quantity-based standards, on the other hand, the industry is forced to reduce absolute numbers of coal mining injuries and deaths. This also places greater emphasis on the individuals and their tragedy and loss resulting from coal mining accidents. Aggressive quantity-based targets are achievable if supplemented with effective enforcement. Gathering and publicizing accurate information is also basic to any solution for coal mining safety. In addition, the government must focus on adequate mine capacity in order to meet both the national coal demand as well as ensure safe working conditions. For this to happen, investment in mining technology, safety equipment and adequate enforcement of safety measures are all imperative. Sufficient funding to ensure appropriate safety measures for Romanian coal enterprises has been chronically neglected. Romania’s coal mining industry and its safety record also raises deeper issues about the nation’s modern social, economic and political life. What is the balance between the country’s needs for rapid economic growth versus the wellbeing of society? How should the overall progress of the nation be measured against the rights of the citizens that comprise it? Fundamentally, these are the thorny questions behind the relations between state and society and the widening gaps that we must address as it moves relentlessly forward.
Revista Minelor - Mining Revue no. 3 / 2012
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