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FEATURE

EROSION CONTROL

CASE STUDY

RECLAIMER TUNNEL

Advanced ground engineering methods help stabilise soils With increasingly strict regulations in place for mine site remediation and soil quality, organisations are examining a variety of methodologies to identify and remediate weakened foundations, soil subsidence, underground voids, ageing assets, and control erosion.

C

ommon issues and challenges experienced in mining environments are as varied as the locations and sites they impact. Subsidence and ageing infrastructure, commonly associated with extracting resources, can bring underground mining operations to a halt and create serious safety hazards that may put lives at risk. Likewise, surface mining sites including open-cut coal mines and hard rock mines, iron ore, silver, lead, zinc, bauxite, copper, and diamond mines can also be prone to issues that require ground stabilisation, re-levelling and asset rehabilitation. Mining operations can also increase the risk of ground subsidence. For instance, high or low frequency mechanical vibration combined with narrow entrances at underground mines can put undue pressure on mining infrastructure. When an asset is out of level or signs of subsidence appear, such as misalignment, cracks, pooling water on the ground, drainage issues, fractured grout pads, jamming belts, or excessive wear on the edges, identifying the cause is a vital step toward determining the best solution.

FINDING THE CAUSE IS KEY TO IDENTIFYING THE RIGHT SOLUTION Pinpointing where the failure or weakness is occurring by analysing the soil conditions underneath the structure or asset is the first step to determining the right type of ground remediation solution required.

A Cone Penetrometer Test (CPT) may be recommended to determine the geotechnical engineering properties of soils and strength of the foundation ground beneath the asset or structure, and can be applied easily and quickly to depths of 10m, subject to equipment used. 50

AUSTRALASIAN MINE SAFETY JOURNAL / Summer 2019 / www.amsj.com.au

Dynamic Cone Penetration (DCP) tests may also be used to gather supporting information to identify the bearing capacity of the soil and where weakness is within the foundation. Geotechnical experts use this data to evaluate the soil conditions throughout the test areas. The information helps identify the weak areas to be targeted in a subsequent remediation program.

UNDERSTANDING SOIL CONDITIONS

Soil or landfill may be imported to the mining site, which means that soil conditions can vary considerably within a horizontal distance of just a few metres and within a 100mm depth. This is why samples should be extracted from a number of areas to thoroughly analyse soil conditions.

CASE STUDY

GROUND REMEDIATION USING STRUCTURAL RESINS TO IMPROVE LOAD BEARING IN SOILS

The Wiggins Island Coal Export Terminal (WICET), a green-field coal export facility which exports Queensland thermal and metallurgical coals through the Port of Gladstone, where weak ground was impacting critical service tunnels. The service tunnels, which were 2.6m in diameter and constructed from a number of pre-cast sections, were at risk of damage or failure due to uneven and uncontrolled ground settlement. If the tunnels had failed, there was a risk that some concrete sections would have to be removed via excavation which would be costly, time-consuming, as well as impacting the safety of the site and WICET’s ability to meet long-standing service contracts. 

Profile for Mining Safety Journal

Mining Safety Journal | Summer Edition  

Australasian mine safety journal provides highly relevant content on the latest mining safety practices, mine safety incidents, mine safety...

Mining Safety Journal | Summer Edition  

Australasian mine safety journal provides highly relevant content on the latest mining safety practices, mine safety incidents, mine safety...

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