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By P A. Grossman, J H. Rubinstein, M Brazil

The installation of truck turntables at above-ground crushers has the potential to yield gains in efficiency and productivity by eliminating the need for the trucks to turn around and reverse up to the crusher to dump their loads. The benefits include savings in time, fuel consumption and tyre wear. In addition, having a smaller area near the crushers dedicated to manoeuvring the trucks can be a significant benefit at some sites. Safety is also enhanced using turntables.This paper describes a project with the Australian Turntable Company to develop software that generates near-optimal layouts for the paths taken by the trucks in the vicinity of the crushers when turntables are present or absent. The geometry of the paths is constrained by the turning radius of the trucks and by the boundary of the manoeuvring area. The software quantifies the benefit of installing turntables by generating a design for paths with turntables and comparing it with the layout in current or planned use by the mining company. Through the use of this software tool, a mining company can readily assess the benefits of using turntables at their site.CITATION:Brazil, M, Grossman, P A, Rubinstein, J H and Thomas, D A, 2014. Demonstrating efficiency gains from installing truck turntables at crushers, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 259–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

Bendigo is AustraliaÆs second-most productive goldfield, having produced some 22 million ounces of gold between 1851 and 1954. Bendigo Mining Limited (BML), the sole lease-holder of the Bendigo Goldfield, is developing a mine that is planned to produce ore from beneath the historical workings for at least the next 25 years. The high-grade Bendigo reefs occur in the proximity of the chevron anticlines, which characterise the goldfield. Typically the reefs display relatively small cross-sectional areas and large (subhorizontal) strike dimensions. They occur in clusters due to interrelated structural controls. Most of the gold occurs as visible grains and laminae, and as such grade estimation is not amenable to ænormalÆ sampling and estimation techniques. The initial phases of exploration and development of the mine focused on understanding and resolving these sampling and estimation issues. In 2005, BML reviewed and updated the March 2004 Feasibility Study, refining the life of mine development strategy. The strategy fundamentally aims to exploit the 11 million ounce Inferred Resource and additional exploration potential by developing the current Kangaroo Flat Mine to produce ore at an initial rate of 450 000 t/yr in 2006/07, expanding to 600 000 t/yr by 2009/10; and developing the Eaglehawk Mine to produce 1 Mt/yr by 2011/12. Ore will be processed initially at the Kangaroo Flat site, and from 2011/12 also at the Eaglehawk Mine 1 Mt/yr processing plant. The two mines will connect underground in 2009. Total ore treatment capacity will be 1.6 Mt/yr, producing 600 000 oz/yr from a head grade of 12.7 g/t gold. The project is planned to operate for 25 years, processing 33.6 Mt of ore producing 13.7 Moz of gold. To achieve this production rate, the exploration and ore delineation programs will require up to 16 diamond drill rigs producing over 200 km of core per year. At the same time, approximately 8 km of on-reef development must be monitored and typically 18 stopes managed concurrently. The processing plants will be located in geographically constrained areas, which will limit the ability for selective stockpiling and campaign treatment.

Jan 1, 2006

A number of gases, such as carbon dioxide, methane, water vapour, nitrous oxide, ozone and chlorofluorocarbons are transparent to incoming short-wave radiation, but are relatively opaque to outgoing longwave radiation. Variations in the concentration of these gases in the troposphere can alter the thermal balance of the earth's atmosphere. Outgoing terrestrial radiation which would otherwise escape to space, is trapped within the inner layer of the atmosphere, resulting in a greenhouse effect. It is estimated that at present greenhouse gases other than carbon dioxide, contribute about 50% to the greenhouse effect. However, in the future, the contribution made to the greenhouse effect by gases other than C02 will become increasingly more significant. Greenhouse gases arise from a wide range of sources and their escalating increease is largely related to an increase in the world's population, an increase in the standard of living of many areas and changes in lifestyle. The effect of increasing man-made greenhouse gases in the troposphere is unknown but it is proposed that it may increase temperature and may modify climate, agricultural response and land use. The sources of greenhouse gases are identified and found to comprise a wide range of activities. The contribution that coals use makes to the greenhouse effect is examined in detail. It is concluded that coals total contribution is small being about 10% of man made greenhouse gases. Envisaged expansion of coal's use will only cause a small increase in greenhouse gas emissions. Whilst developing technology for coal's use for power generation has the potential to reduce greenhouse gas emissions from new plants by approximately 25%.

Jan 1, 1989

A short overview of the research program of SveBeFo, Swedish Rock Engineering Research, which was founded in 1993 is first given. Then four recent and ongoing projects in rock blasting and explosives engineering are presented in greater detail: 1. Burn Equations for Commercial Explosives. 2. Blast Damage in Contour Blasting. 3. The Role of Gas Pressure in Pit Wall Damage. 4. Fragmentation of Aggregate Rock. The goal of the bum equation project is to be able to control the energy release from explosive charges to the desired part of the expansion curve of the reaction products under various rock conditions. SveBeFo's work has reached the stage where a burn equation for a lab emulsion has been established which can model the influence of charge diameter on the VOD and detonation front curvature in a cylindrical charge quite well. This work now continues with other emulsion recipes. In the blast damage project the goal is to develop techniques and recommendations on how to minimise the blast damage in construction blasting. The project has gained extensive practical knowledge from the blasting of more than 200 holes in a granite quarry under controlled conditions. The cracks in the rock surrounding the contour holes have been cut open and measured. The influence of factors like charge concentration, decoupling ratio, hole and charge size, VOD and time delay in initiation have been investigated. A simultaneous initiation of a group of contour holes with EDD detonators is quite superior to single hole blasts, even when they are timed as closely as 1 ms.

Jan 1, 1995

By T Kitajima, T Kawaguchi, T Nakamura

Carbothermic reduction of iron oxide is an attractive mechanism to produce metallic iron, since it can directly utilise coal as both reductant and fuel. To improve energy efficiency and productivity of the metallic iron production based on this mechanism, the combustion bed process packed with the composites of iron oxide and coal powder was experimentally evaluated. The process has a potential of high heat efficiency since it can automatically utilise the heat of reduced materials as that necessary to the subsequent reduction of the composite by a large heat exchange rate between the packed particles and gas flowed across the bed. However, it is hard to perfectly prevent the reoxidation of formed metallic iron in the bed. The present paper reports the effect of coal content, pellet size and so forth on the reduction/metallisation degrees of the samples after the reduction experiment. It also discusses the effect of pretreatment of the composite pellets using CaO bearing materials to suppress the reoxidation of formed metallic iron in the bed.

Jan 1, 2000

By D La Rosa, A Jankovi, A Dance, W Valery

This paper presents the methodology for optimising blasting and comminution processes in terms of fragmentation developed by Metso Minerals Process Technology Asia-Pacific and South America (MMPT). The methodology is called process integration and optimisation (PIO) and involves a number of steps: benchmarking, rock characterisation, measurements, modelling/simulation of blasting and comminution processes and where required, material tracking. The measurements collected while at site are combined with rock characterisation and definition of ore domains to model the complete process chain. These data are used to develop site-specific models of blast fragmentation, crushing, grinding and flotation. This allows customised blast patterns to be developed that optimise both crushing and grinding performance. For each domain, blast designs are recommended to generate the optimal fragmentation size for downstream processes. The objective is to minimise the overall cost for the entire process and the changes often have a positive impact on the mining operation. Process constraints such as wall stability, ore dilution, muck pile characteristics, size of mining equipment, size and installed power of crushing and milling equipment and other process bottlenecks are considered in the blast designs. This methodology has allowed many operations around the world to significantly increase their production: generating typically five to 20 per cent higher concentrator throughput. A number of case studies will be discussed in this paper to describe the structured approach taken and demonstrate the benefits that are achievable. This paper will focus on the role of blasting in the optimisation of the entire mine to mill process chain and discuss elements of the PIO methodology: rock characterisation, fragmentation modelling and measurement, the relationship between fragmentation and mill throughput and material tracking.

Jan 1, 2007

In the general planning of this area, provision was made for the distribution over the whole area as required of the following services:(a) Power and lighting from the substation distribution boards 'located in the winder house.(b) Miscellaneous electrical indicating, control and signalling systems.(c) Telephone lines from the main internal automatic exchange located in the changehouse, the town exchange to the automatic exchange and also direct lines from the town exchange to selected offices.(d) Compressed air from the incoming 16-in. air main. (e) Water, both unfiltered and filtered; and the disposal of the following effluents:(f) Sewage from the area to the town sewage system.(g) Changehouse shower water to the regeneration area.(h) Storm water to the general mine surface drainage system leading out to the naturally drained area north of the No. 8 Shaft.

Jan 1, 1957

By Agrawal A, Joshi A

Mochia mine, in culmination of depillaring operations, fired India's largest underground pillar blast consuming 145 tonnes of explosive and yielding 0.55 million tonnes of ore in June 1994. To protect main mine structures (situated at a distance of 250 to 350 m from the blast site) from resultant ground vibrations, the charge per delay was restricted to 2300 kg. The post-blast observations revealed that no damage was caused to these structures. However, the damage assessment survey of the mine workings situated in close proximity revealed a general trend in consonance with the distance from the blast and found to be well correlated with peak particle velocity.

Jan 1, 1995

The discovery of copper and nickel sulphides in the Riwaka Complex in 1967 led to considerable exploration activity by a number of companies. Various exploration techniques used by these companies are summarised and discussed. Activity of these companies shows that mineralisation is mainly confined to the southern, ultramafic section of the Riwaka Complex where geological mapping recognised sixteen units within, or associated with the Riwaka Complex. Significant pyrrhotite, pentlandite chalcopyrite mineralisation is restricted to biotite feldspar pyroxenites and to clinopyroxenite units. Lesser and more erratically distributed pyrite chalcopyrite pyrrhotite mineralisation occurs in poikilitic pyroxene hornblendites, melanocratic gabbros, and in marginal diorite lenses. It is suggested that a linear belt of layered ultramafic and mafic rocks described in Fiordland by Williams (1974) may be a southern extension of the Riwaka Complex. The Riwaka Complex has been classified as belonging to the Picritic subtype, (Tholeiitic suite), of Naldrett and Cabri, (1976), and as such it is concluded that it exhibits substantial potential for the discovery of economic copper and nickel deposits. It is considered that the complex is a multiphase differentiated intrusion emplaced in a major tensional fracture zone that developed in a relatively stable tectonic environment, namely a succession of middle Paleozoic shallow water shelf sediments. Based on sparse available evidence it is suggested that the Riwaka Complex was intruded in the lower to middle Permian. It is further suggested that the tensional fracturing was initiated by the onset of subduction process which were responsible for the development of the Permian volcanic arcs and ophiolite belt in the north west Nelson area.

Jan 1, 1977

By T C. McCuaig, D B. Mapleson

The Wannaway Deposit is a structurally modified komatiite-hosted nickel-sulfide deposit. Until recently, nickel sulfide accumulations surrounding the Widgiemooltha Dome had been studied with a focus on understanding volcanological aspects of komatiite flow regimes and nickel-sulfide accumulation. Although volcanological features can be observed at Wannaway they are overprinted by several generations of structures associated with multi-phase deformation of the Dome. On the mine scale, two significant deformational events can be distinguished that control ore distribution. The first deformational event is represented by the formation of a layer parallel foliation within the footwall metabasalt and boudinaging of the ore into two distinct orebodies (mega boudins) during a north-south compressional event. Evidence of a second compressional event (east-northeast-south-southwest) is defined by reverse > dextral thrust-folding of the ore zone. The latter deformational event focussed the sulfide ore into thrust front positions where folded ore sequences are mined with stope widths up to nine metres wide. Later stage compressional and extensional deformation phases are observed but have minor, localised effects on the geometry of the ore zone. Four orders of control on the geometry and distribution of ore are interpreted through a combination of primary and secondary features observed at Wannaway. Extending the structural aspects of the secondary overprint features into areas of potential mineralisation has not only defined targets for extensions to the Wannaway Deposit, but has also aided to delineate high grade mineralisation and aid mining decisions. Obtaining an understanding of the volcanological conditions of formation, and more importantly, the structural evolution of the Wannaway region has been an integral part in optimising production.

Jan 1, 2003

By Stone AM, Romensky G

The requirement for economic operation of unit trains carrying bulk materials has dictated that rapid and accurate bulk loading methods be provided. The train loading station at Phosphate Hill, built for Queensland Phosphate Ltd. to load rock phosphate, provides this facility and whilst the concept used is not unique, it contains a number of novel features that are considered to advance the "state of the art'' in this field. This paper briefly reviews some alternative concepts evaluated, and describes the design and operation of the scheme ultimately selected as being most appropriate to the project requirements. it is one which utilises a variable speed belt feeder whose speed is controlled in proportion to the weight rate of material moving on the belt as measured against a set point

Jan 1, 1978

By Mendeckl A. J

Anglo American Corporation has always viewed technological development as vital and as such has placed research and the implementation of new technological practices high on its priority list. Support is given to a number of research institutes but a significant degree of reliance is placed on in-house research carried out at individual companies and at the Group's main laboratory complexes. The Corporation's interests are diverse with advanced practices and innovative technology ranging from new battery technology with wide application to deep level shaft technology with very specific application. In this paper, we aim to concentrate on a particular system developed primarily for use in seismically active deep mines. The system has proved to have far wider application and has the potential to be further enhanced to meet the needs of users across a broad range within the industry and even beyond. As the nature of this conference is to inform delegates of advanced mining practices, we should simply mention that we could have talked on subjects relating to the advances made in deep level winding technology including winder drive and brake control to alleviate dynamic rope loads, shaft steel design for high pay load high speed winding and shaft safety systems such as slack rope devices and moving lip loading facilities to cater for rope stretch. Other areas of interest relating to refrigeration using ice technology or non-explosive rock cutting using diamond wire or saw technology could also have been of interest. As the South African gold mines become deeper and the problems associated with depth become more acute, answers had to be found and systems developed to cope with very high rock stress and the related seismicity. The fundamental understanding of the behaviour of the rock mass has always been important but became critical on our mines to ensure the safe extraction of the orebody. Basic research into and the application of physics, applied mathematics, seismology, rock mechanics, electronics and computer technology have helped us to develop the Integrated Seismic System - Integrated because of the system's abilty to monitor seismic and non-seismic sensors simultaneously and because it encompasses data acquisition, processing and interpretation into one system. The system which is in use at all our gold mines has found application not only in South Africa but also in such locations as Australia, Chile, Canada, Europe and Japan. A highly motivated team of scientists under the leadership of Aleksander Mendecki developed the majority of the hardware and software needed for the system. In essence, the system allows us real time monitoring of energy release and stress transfer data that with the aid of modern computers is turned into useful information. The information so obtained has allowed us to improve our mine and extraction designs to minimise the inherent hazards. The system has proved to be an extremely useful management tool as substantiated by the demand for the product. The paper is intended to convey to the reader the technical concepts and the presentation is intended to demonstrate the usefulness of the system.

Jan 1, 1995

By D Wallace, H Guo, B Shen

Appropriate management of the ground subsidence induced by coal mining activities is essential. To assess the effectiveness of grout injection for mining subsidence control, time-lapse ground penetrating radar (GPR) imaging data were collected before and after grouting. The pregouting subsurface responses were interpreted to have changed after grout injection. The changes were caused by injecting the grout materials (flyash and water) into the delaminated strata and permeable fracture zones. The largest distance of the observed GPR event changes at the right end of the main profile is 132 m away from the injection borehole. Although the GPR images could not easily tell if the image changes were caused by the injected ashes or the water, it does suggest that the injection materials had been pushed at least 130 m away from the injection borehole. This is consistent with the borehole scan monitoring, which confirmed that the grout has travelled more than 90 m from the injection borehole.

Jan 1, 2006

By F Minz, P Lamberg, A Mwanga, C Lund, C Wanhainen, M Amiri Parian, J Rosenkranz

A geometallurgical model is currently built in two different ways. The first and the most common way relies on geometallurgical testing, where a large number of samples are analysed for metallurgical response using small-scale laboratory tests, eg Davis tube testing. The second, mineralogical approach focuses on collecting mineralogical information over the orebody and building the metallurgical model based on mineralogy. At Lules University of Technology, Sweden, the latter method has been adopted and taken further in four ongoing PhD studies. The geological model gives modal composition by the help of element-to-mineral conversion and Rietveld X-ray diffraction. Texturally, the orebody is divided into different archetypes, and liberation measurements for each of them are carried out in processing fineness using IncaMineral, a SEM-based technique. The grindability and liberation spectrum of any given geological unit (sample, ore block, domain) are extrapolated from the archetypes. The process model is taken into a liberation level by mass balancing selected metallurgical tests using the particle tracking technique. The approach is general and can be applied to any type of ores. Examples of ongoing studies on iron and massive sulfide ores are given.CITATION:Lamberg, P, Rosenkranz, J, Wanhainen, C, Lund, C, Minz, F, Mwanga, A and Amiri Parian, M, 2013. Building a geometallurgical model in iron ores using a mineralogical approach with liberation data, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 317-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Evans A, Jones O

Surface subsidence resulting from "total extraction" of coal in the Collie Basin first occured in 1987 when Western Collieries Ltd trialled the Wongawilli mining method. Because very little quantitative subsidence data existed for the weak, Permian sediments, a research program was set up prior to the extraction of the first panel. The objective of the study was to be able to predict subsidence characteristics and effects prior to mining future total extraction panels. Attempts at predicting subsidence began using existing subsidence models from other coal mining regions, however, as more site information became available, it became clear that it was necessary to develop a separate, she specific predictive model for the Collie Coal Basin. Analysis of extensive field monitoring data for both surface and subsurface subsidence has produced a series of empirical models which can predict the shape of surface subsidence troughs and corresponding tilts, and strains for rectangular panels and describe the sequences of ground movement from the mine roof through to the ground surface.

Jan 1, 1992

By D Thornton

Geologists use large data sets and spend many hours and much computing time modelling the distribution of minerals throughout a rock mass. Significant investments in drilling, assaying and quality assurance and quality control (QA/QC) are made before sophisticated geostatistical techniques are applied to the collected data. A large amount of research has been done in this field such that the ore control model is a reasonably accurate reflection of the mineral that is actually in the ground. However, after all this effort, the mining engineers then work just as diligently to blast the in situ rock mass to a particle size that can be efficiently handled and further reduced by downstream comminution processes. In open cut mines, this invariably requires large amounts of explosive energy that displaces the ore boundaries from where the geologists originally defined them. Failure to accurately account for blast movement will result in misclassification, whether that is ore to waste; low grade to high grade; sulfide to oxide; or other contaminates û collectively referred to as ore loss and dilution. The financial consequence of getting this wrong is substantial and not well quantified. This diminishes all of the good geological QA/QC done in defining the ore. This paper discusses various technologies used to physically measure blast-induced orebody movement and the difficulties in modelling this with a purely theoretical approach. Rock mass structure, blast energy, design and timing contours all have significant and interrelated effects on blast movement vectors. Measured blast movement has a large variance due to the uncertainly of many of the controlling parameters û arguably dominated by the heterogeneous nature of the rock mass. Although there have been significant advances in blast movement modelling capability in recent years, this unpredictable blast movement limits their use in the context of production ore control. Certainly, without physical field measurements, accurate predictions of movement are near impossible.Limitations of traditional surface markers in determining three-dimensional (3D) blast movement within the orebody are also reviewed, and advancements in accurately measuring these vectors within blasted ore discussed

Sep 26, 2011

By H M. A Ilyas, M Yahyaei, S Amari, M Darestani

Tailings are generally deposited on or near to the mine sites, occupying the site area, and being an economic burden for mining companies. Tailings can cause several environmental impacts, such as leaking toxic substances and contaminating underground water, emitting greenhouse gases, and damaging natural bodies and wildlife. Geopolymerisation of mine waste effectively transforms mine waste into more valuable, environmentally friendly products. Geopolymers are inorganic aluminosilicate materials that are widely applied in the construction industry (Araya, Kraslawski and Cisternas, 2020). The high performance and the low-CO2 emission of geopolymers make this type of material potentially more desirable than ordinary cement, given that manufacturing one ton of traditional cement generates approximately 0.8 tons of CO2. This process is seen as a promising method for repurposing tailings and reducing the environmental impact of mining waste. However, the environmental impact of geopolymer production is not sufficiently comprehended (Mazzinghy et al, 2022). Moreover, geopolymerisation of mine waste can offer several economic benefits, including reduced waste management costs (Amari et al, 2019; He et al, 2022), reduced raw material costs, and potentially lower production costs. However, there are several challenges that need to be addressed to ensure the economic feasibility of the process. This study aims to demonstrate the potential environmental impacts of geopolymer concrete produced using mine wastes and industrial by-products such as blast furnace slag (BFS). For this, a comparative cradle-to-gate life cycle assessment (LCA) methodology was conducted on different geopolymer mix designs, and the greenhouse gas (GHG) emissions results were compared to the ordinary cement. LCA can be used to evaluate the environmental impact of geopolymerisation of mine wastes in various ways. One important impact category is GHG gas emissions, which contribute to climate change and is the focus of this study. Another aim of this study is to evaluate the economic feasibility of the geopolymerisation of mine wastes via economic analysis (EA) to identify the key economic factors and trade-offs associated with repurposing mine wastes through geopolymerisation.

Aug 2, 2023

By M Miller

Operators of nickel laterite pressure acid leach and gold pressure oxidation technology frequently employ a series of steam condensing heaters to preheat the leach feed slurry. The heaters are an economic pinch point û although the thermal performance of the heaters is critical to overall process viability and operating cost minimisation, they are also a significant capital item and must be sized accordingly. Despite this, discussions of the factors underlying heater design are conspicuously absent from technical literature, and existing operations feature a conflicting range of heater sizes and configurations. This variety would suggest that at least some of the chosen heater designs are oversized. As part of its detailed design stage, the Ravensthorpe Nickel Project (RNP) constructed and tested a pilot plant heater to develop an understanding of the heating process and to ensure that the RNP heaters were appropriately sized. This testwork used RNP slurry at design density and viscosity on a 450 mm diameter, 6500 mm high column. The pilot plant testwork demonstrated the intrinsic efficiency of the direct steam condensation heating process, which was essentially independent of slurry density and viscosity. Presence of non-condensable gases in the steam phase decreased the heat transferred in certain circumstances, but heater performance remained consistent with thermodynamic limitations. Stagewise heat transfer within the column was rapid, and suggested either a very high slurry surface area or excellent heat transfer within the slurry phase. While the testwork did not set out to distinguish between these effects, physical evidence pointed to droplet formation in the inter-tray shower zone, giving a high heat transfer area. For scale-up purposes, the key facts were that the heat transfer rate was not limited by using high viscosity slurries and heaters could be designed using the principles applied to the smaller of those in existing operations. This paper discusses existing slurry heater designs, the current understanding from open literature, the pilot plant testwork, results and analysis, and scale-up to commercial sized equipment.

Jan 1, 2005

By Muldoon T

Water sprays on mining machines are generally put there to reduce dust; however, research by the Bureau of Mines and others has shown that considerable airflows may also be generated by these sprays. This recognition of water spray-gen- erated air movement led to the "Spray-Fan" - a continuous miner auxiliary ventilation system which was shown to reduce methane peaks by a factor of 15. Recent successes and failures of the Spray Fan are reviewed. More recently, the same principles were used in the design of the "Shearer- Clearer" for reducing dust at longwall shearer operators. The original design was successful; however, a new design is now available which is more practical to install and does a much better job of holding the dust against the face downwind of the shearer. The latest research objective is to eliminate the negative impact of spray- generated air turbulence on continuous miner dust control. Most coal faces in the USA are ventilated in the exhaust mode using "line curtain", and the forward airflow on the side of the heading opposite the curtain is inevitably weak. Air turbulence generated by sprays which are incorrectly located and/or operated at excessive pressures can cause roll back - in which the dust cloud at the face is forced unwind against the ventilation and spreads over the miner cnerator. The general approach to reducing "roll back." is reviewed and art anti-roll back water spray system is presented.

Jan 1, 1983

By D J. Williams, E M. Rykaart

Soil cover systems are routinely used to reduce acid rock drainage (ARD) from mine waste rock dumps and tailings impoundments. A technology for the analysis, design, instrumentation and monitoring of barrier-type (oxygen limiting) and store/release-type covers has rapidly developed and the number of covers under construction has grown extensively during the past ten years. Mine operators are currently investing in this relatively new technology with the expectation that these covers will reduce long-term liability with respect to acid generation, drainage and treatment costs. While the design life for cover systems may extend into hundreds of years, we have less than ten years of construction experience and proven performance. Some cover designs appear to be functioning well; however, the performance of many more is now being called into question. The paper presented herein evaluates the integrity of cover systems from a global perspective. Soil cover systems for the control of ARD are being constructed at mine sites located within high rainfall equatorial regions, deserts ranging from low to high latitude, humid temperate regions, and cold-continental climates. While the technology for analysis and design of soil cover systems is well developed, factors that compromise the performance of cover systems (in addition to the paramount issue of climate) relate to material selection and availability, cost and construction practices. Long-term performance is also strongly affected by physical stability (ie erosion), volume change (ie cracking, desiccation, settlement and freeze/thaw cycling), vegetation, soil evolution and ecological stability. This paper provides a review of the application of soil cover systems for the control of ARD. Cases where cover systems have been constructed with both success and failure are illustrated. General criteria and recommendations for cover selection, design, construction, and maintenance are provided.

Jan 1, 2003