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By Cox A

A key concern both in public perceptions of the environmental performance of the mining industry and in the development of policy relating to mining activities is the state in which the areas may be left at the completion of mining operations. There is, in effect, concern that the transient economic benefits of mining are enjoyed by the few, while the 'scars' may remain for all. While the techniques of mine rehabilitation have improved rapidly in recent years, an important set of economic issues has generally been neglected.In this paper, the economic and policy aspects of mine rehabilitation are examined. The key issue addressed is how to determine when expenditure on rehabilitation should stop. The answer to such a question requires consideration of the full range of social, as well as private, costs and benefits of rehabilitation at a particular site. Clearly these costs and benefits will vary between sites. From both an economic and policy perspective it is important to establish whether the additional gain from more rehabilitation would exceed the additional cost.It is concluded in the paper that the technical feasibility alone does not justify a paeticular level of rehabilitation activity and expenditure. While more rehabilitation at a particular site may be technically feasible, the additional expenditure incurred in undertaking that rehabilitation may result in little extra benefit. This conclusion has important implications for government policy, particularly with respect to establishing the goals for rehabilitation, criteria for successful rehabilitation and enforcement of rehabilitation objectives.

Jan 1, 1992

By K Matsui, T Sasaoka, S Kubota, Y Yosh

A large amount of wastes from the preparation plant is produced. The properties of these wastes vary depending on the mineralogical contents of the mother rock in which the coal is embedded. The waste quality depends on the method of mining and cleaning. The waste mainly consists of clays, quartz, carbonaceous materials, mica, pyrites and so on. About 55 per cent of coal-ash is now utilised and the remains are disposed of at the disposal sites, however, the life of the disposal site is limited. Moreover, it is difficult to find new disposal sites. Therefore, it is requested that the percentage of the utilisation of the coal-ash be increased in every field in Japan. So, it is very much available if the injection material for natural/artificial openings can be applied on the cement that is added to flyash. Among the man-made pozzolans, a flyash is probably the most successful component used in grout injection. When flyash is added to Portland cement concrete, the same kinds of oxides as those of the cement are being added. As an injection component, flyash acts, in part, as a fine aggregate and, in part, as a binding component. However, there is not a substantial alteration of the properties of the original component. From these points of view, in order to clarify to what degree the flyash content affects the properties of the injected grout mixture; different combinations of flyash, Portland cement and water were considered by means of several experiments.

Jan 1, 2003

By Gray E, Banks J

In mine site revegetation, exotic grasses are more commonly used than native grasses. This is due to unavailability of native grass seed on a commerical scale and lack of information on agronomical aspects of native grasses. This paper lists a number of native grass species that have the potential to grow well on mine sites, and provides some information on their seed collection, processing and germination. Further, it demonstrates via results of a field trial conducted at Ranger Mine spoil the relative performance of ten native grasses and Rhodes grass. It is concluded that (i) some native grasses have similar ability to grow on mine spoils compared to Rhodes grass and (ii) the use of native grasses have added advantages in ecosystem restoration.

Jan 1, 1994

By Smith C. B

Major diamond pipes discovered in Western Australia in the late-1970s exhibited a number of unique features that not only resulted in Australia becoming the largest diamond producer in the world in volume terms by 1986 but also changed geological thinking on the primary occurrence of diamond. They were: - lamproite is an alternative primary diamond host to kimberlite. - the extremely high mean grade of the Argyle lamproite pipe at 5 ct per tonne. - the tectonic setting of the lamproite pipes in mobile zones mar- ginal to the Kimberley Craton in contrast to the traditional African setting within stable cratons. Diamond was one of the earliest economic minerals discovered in Australia but 128 years elapsed between its first recognition and the first Australian economic pipe discovery (Argyle). During that period some 200,000 ct of alluvial diamonds were mined in Australia (mostly in New South Wales), but such alluvial output is insignificant on the world scene where annual production today runs at 95 million ct of natural stones some 76010 of which comes from primary pipe sources such as Argyle which alone produces 30 million ct per annum. Of particular significance therefore is the geological nature of the primary diamond source rocks in Australia. The Argyle and Ellendale Pipes are lamproites, differing from kimberlite in their mineralogy and geochemistry, and characterised by the presence of typical lamproite minerals such as leucite, priderite, potassic richterite, and the abnormally high content of chemical elements incompatible with ultramafic rocks. But not yet widely appreciated is that many other Australian olivine-rich lampro- phyres also contain diamond. Such picritic alkaline rocks can

Jan 1, 1988

This research is about human development and socio-economic progress of the main mining areas of Chile in the period 1990 - 2007, and especially about the positive effects that mining activity has on poverty reduction and indicators related to the Millennium Development Goals of the United Nations. The analysis is doubly interesting, if one considers that the economic and social developments in Chile, recognised and prominent among the Latin American economies and developing nations, are more evident in mining areas as Tarapacß and Antofagasta (northern Chile), which concentrated than more 70 per cent of investments and mining assets in the country. Additionally, the study concludes with methodological reflections for the evaluation of socio-economic impact in the mining industry in developing countries.

Jan 1, 2009

By J Borthwick, M Yusi, M Douge

Feasibility studies form a vital and significant component of the project delivery cycle. They are at the heart of the valuation process. This paper focuses on variables which can affect a project and how these are assessed as part of the decision-making process through feasibility studies. Test work and site selection needs; the degree of engineering required to meet the study requirements and the quality of owner project information are discussed. Also, local factors including permitting needs, social, environmental and government relations are considered. Engineering and site factors are crucial in the estimating process. The interaction of detailed engineering, engineering assumptions and estimating methodologies are therefore examined. The ownerÆs perspective is considered along with risk analysis, which is fundamental in project feasibility study activities. The impact of this is also discussed.

Jan 1, 2009

By D Schwab, R M. Tosdal

The Quesnell-Stikine arcs, in the Canadian Cordillera, are host to Triassic and Early Jurassic alkalic porphyry Cu-Au and calc-alkalic porphyry Cu-(Mo-Au) deposits formed outboard of ancestralNorth America in island-arc tectonic settings (McMillan, 1991). The majority of the alkalic porphyry Cu-Au deposits are products of a discrete magmatic event at the end of the Triassic, with a second and smaller event in the Early Jurassic (Mortensen, Ghosh and Ferri, 1995). Of the Triassic complexes, the Galore Creek alkalic intrusive suite is one of the largest and most silica-undersaturated intrusive complexes, and host to the most significant undeveloped alkalic porphyry Cu-Au resource in North America (Lang, Stanley and Thompson, 1995). Because of the common presence of feldspathoidal-bearing rocks in the complex (Enns et al, 1995), Galore Creek likely represents an end member example of the alkalic porphyry Cu-Au class. The Galore Creek alkalic Cu-Au-Ag porphyry district, located in NW British Columbia (Canada), contains 12 mineralised prospects (Enns et al, 1995; Micko et al, 2007; Schwab et al, in press) with a total measured and indicated resources of 785.7 Mt at 0.52 per cent Cu, 0.29 g/t Au and 4.87 g/t Ag (NovaGold Resources Inc, February, 2008). The Central Zone is the largest and best delineated. Other economically important mineralised centres include the South-West, Bountiful, West Fork and Junction deposits. The South-West Zone, the focus of this contribution, is a Cu-Au-Ag breccia-centred deposit with a measured and indicated resource of 69 Mt grading 0.42 per cent Cu, 0.69 g/t Au, 2.67 g/t Ag. Hosted in brecciated intrusive rocks, the South-West Zone is distinctly younger than the Central Zone and most of the other mineralised centres (Enns et al, 1995; Schwab et al, in press). The South-West Zone therefore preserves the late stages of hydrothermal evolution at Galore Creek. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

A description of:1. Air-lock at No. 14 Upcast shaft.2. Pit-top gates at Dudley winding shaft.3. Safety rider employed in sinking No. 18 shaft.1. AIR-LOCK AT No. 14 SHAFT.Some time ago it became desirable to raise and lower the McBride tunnel men to save them walking the inclined tunnel, about a mile in length, with a dip of nearly 600 ft., and a maximum gradient of 1 in 4. The main Upcast shaft, No. 14, was, therefore, equipped for winding the men. As this shaft was the main ventilating shaft for the McBride tunnel mine, it was necessary to take the greatest precautions against leakage of air. The writer therefore devised the concrete structure shown in Plate 1.The structure, as shown, surrounds the shaft inside the poppet legs. As the men are wound on double-decked cages (twelve men to each deck) provision is made at both top and bottom for the two decks to be loaded and emptied simultaneously. The doorsover the sky shaft, shown in the drawing, have been cut out and the sky shaft has been close-timbered with a double layer of T. and G. flooring boards, with building paper between, nearly up to the thimble frame, a small hole only being left for the winding rope topass through. The space between the ramps is glazed with plate glass to allow the winding-engine driver a good view of the pit top.The men are wound from two levels, 302 ft. and 611 ft.2. PIT-TOP GATES AT DUDLEY WINDING SHAFTTo minimise the shock to cage, couplings and rope when winding quickly, the writer devised the apparatus and arrangement shown in Plate n.

Jan 1, 1928

By Z U Bajwah

During the Palaeoproterozoic, a large number of granitic intrusions were emplaced in the various parts of the Pine Creek Geosyncline (PCG). In the central region, the granitic magmatism is represented either by the coalesced mass, eg the Cullen Batholith, or individual plutons such as the Mount Bundey Granite which together with the Mount Goyder Syenite intrude the metasedimentary strata, causing wide spread contact aureoles. Some of these granitic intrusions are temporally and genetically related to gold (and less commonly base-metals) mineralisation present in the adjacent metasediments. These plutons are characterised by the presence of biotite and homblende which appear late in the paragenetic sequence. Electron microprobe analyses of biotite and homblende show that these minerals are poorly to moderately zoned. Biotites are characterised by a decrease in Fe/(Fe + Mg) ratios when plotted against AIVI. Similarly a modest decrease in Ti from centre to the margins of the biotite crystals has also been observed. Furthermore, an increase in Mg/(Mg + EFe) ratios from centre to the margins as well as in mafic to felsic rocks is also apparent. On the other hand, homblendes from the granitic bodies display less well marked trends and are poorly zoned. However, they show systematic increases in Mg/(Mg + EFe) ratios, and decreases in Fe, Al"' and Fe/(Fe + Mg) ratios, when plotted against Si. Magnetic susceptibility measurements on powdered samples of the plutons give results characterised by high values ranging from 0.8 x 10-4 to 2.0 x 10-3 emu/g which place the granites in magnetite- series field. This indicates that the oxidation state of the magma was high during crystallisation. The range of chemical compositions of the mafic phases indicates a rise in the oxidation state of the magma as it progressively became saturated in H20-volatiles and other metals, not partitioned into the earlier crystallised phases in the final stages of magma consolidation. These variations in chemical compositions also indicate that initially fOz was high and became progressively higher during fractional crystallisation of magmas; this subsequently led to the emanation of hydrothermal fluids responsible for the mineralisation in the adjacent metasediments.

Jan 1, 1994

By D Michaelsen, S Miller

The Grasberg Mine is a copper and gold open pit mine operated by PT Freeport Indonesia (PTFI) and located in the high equatorial mountains of the Indonesian province of Papua. The climate is alpine/subalpine with little seasonal variation in temperature or rainfall. The daily average temperature ranges from about 2¦C to 14¦C and the annual rainfall in the vicinity of the mine and overburden stockpiles is about 4000 mm to 5000 mm. Mining of the Grasberg open pit will continue until 2014 at which time approximately 2750 Mt of overburden will have been produced. Current overburden production rates are 200 Mt per annum. The current mill rate is 230 000 t/day from the Grasberg pit (190 000 t/day) and the underground operations (40 000 t/day). The acid rock drainage (ARD) issues associated with overburden from the Grasberg operations were identified early in the mining operation. Almost all overburden placed to date has been Potentially Acid Forming (PAF). Laboratory testing has identified four main overburden types: limestone and non-acid forming (Green waste), PAF low capacity (Blue waste) and PAF high capacity (Red waste), and Heavy Sulfide Zone (HSZ), which contains greater than 20 per cent pyrite. Waste type block modelling indicates that at least 30 per cent of the overburden production from 2003 to the end of Grasberg pit operations will be limestone. Strategies are being developed to maximise the beneficial use of limestone through strategic blending and placement for ARD mitigation and control.

Jan 1, 2003

By J Zhang, L Klemettinen, A Jokilaakso, J Biswas, J Partinen, H O’Brien, A Klemettinen

Waste lithium-ion batteries (LIBs) are important secondary sources of many valuable materials, including Critical Raw Materials (CRMs) defined by the European Union (EU): lithium, cobalt, manganese, and graphite. Additionally, LIBs typically contain nickel and copper, which are classified as Strategic Raw Materials for EU since 2023. In recent years, great effort has been made to develop efficient recycling processes for waste LIBs. Pyrometallurgical processes have been essential in industrial production of metals for many decades. These technologies are relatively mature, with high adaptability for different raw materials. Pyrometallurgical treatment in LIB recycling typically involves the use of smelting processes, in which waste batteries are heated above their melting points and metals are separated through a reduction reaction in the liquid phase. Through this recycling route, cobalt, copper, and nickel can be efficiently recovered in the form of a metal alloy, whereas lithium and manganese are lost in the slag phase. The goal of this work was to increase the recoveries of valuable battery metals through a combination of hydro- and pyrometallurgical unit operations. First, industrial Li-ion battery scrap underwent a selective sulfation roasting stage, where the aim was to transform LiCoO2 and Mn-oxides into Li, Co and Mn sulfates. After roasting, the battery scrap was leached in distilled water with a solid to liquid ratio of 100 g/L at 60°C and recovered 95 per cent of Li, 61 per cent of Mn and 35 per cent of Co. After leaching, the solid leach residue was mixed with industrial Ni-slag and biochar, followed by reduction at 1350°C in argon atmosphere. The high-temperature smelting experiments were conducted as a function of time (5–60 mins) to investigate the reduction behaviour of battery metals. The results show that Co and Ni from the slag and leach residue can be efficiently recovered in the slag cleaning stage.

Jun 19, 2024

The long-term production schedule of open pit mines that maximises the net present value (NPV) of a given project relies on the proper design of phases (pushbacks) within the ultimate pit limits. There is not a phase design algorithm applied in the mining industry today that gives yearly production schedules that are optimum.The majority of phase design algorithms currently in use by the mining industry aims at grouping the blocks that fall within the ultimate pit limits into phases such that the average value of the blocks within each phase decrease as the size of the phases increase. Current phase design methods are typically based on a pit limit optimisation algorithm, originally introduced by Lerchs and Grossmann (LG) in 1965. To obtain multiple pit shells to be used for the phase design, the LG pit limit algorithm successively applied to economic block models by changing the price of the commodity or some other factor that properly parameterises the size of the pit. These modified economic block models are developed by predetermining the destination for each block in the model based on a breakeven analysis and highest economic outcome between alternative destinations. Phase designs determined by these existing algorithms may be suboptimal if a given project utilises multiple processing facilities for metal recovery and particularly if these facilities have restrictions (constraints) that require blending of attributes in the feed. To overcome these problems in obtaining phases that optimise overall production schedules, a new algorithm is developed at the Colorado School of Mines. The algorithm determines the phases of an open pit mine by taking into account multiple process options for the blocks and period by period blending requirements. This algorithm has been implemented within a software program (the software) and is being prototyped successfully in the design of improved pushbacks at a copper mine in South America and on a gold mine in Nevada. This presentation will demonstrate the shortcomings of the traditional phase design methodologies based on comparison of results coming from the new approach versus the traditional.

Dec 6, 2010

By Akerkar D. D, Dey M. L, Mathur S. B, Chowdhury S. K R

The extraction of gold and silver from chalcopyrite concentrates has been investigated. In view of the recent interest in non-cyanide leachants for gold and silver, one such alternative reagent, namely thiourea, has been employed in the present work. Precious metal leaching was attempted from received copper concentrates as well as pre-oxidised concentrates. Pre-oxidation of the concentrates was carried out by three different methods, namely roasting, pressure oxidation and biological oxidation. After pre-oxidation and leaching of the base metals, the leach residues were subjected to further leaching for precious metal extraction. The results obtained on the extraction of gold and silver from received concentrates as well as pre-oxidised concentrates are presented and the effectiveness of the three pre-oxidation routes employed is compared.

Jan 1, 1992

By Subrahmanyam T. V, Rao V. D

GOLD, the most important and highly coveted valuable metal, is being sought and exploited in almost all the geological environ- ments by the developed, developing and underdeveloped coun- tries of the world. Brazil, one of the five largest countries of the world, has similar geological and lithological environments as of Africa, Australia and Canada and also produces this noble metal. With the recent gold rush in Serra Pelada Hill in Para State of Brazil and the consequent migration of a large number of enter- prises to the Amazon region in search of geological conditions similar to that of Serra Pelada, the status of Brazil in gold produc- tion has been considerably elevated to be among the first five of the world. The principal geological environments or the lithologies where gold can be explored are the greenstone belts, banded iron for- mations, quartz lodes and placers; and the tectonic controls like shear zones in these horizons, or the tectonic relics or the annular- structures that limit the quartz vein systems in felsic as well as volcanogenic systems and epithermal models. The greenstone, BIF associations are present in all the Archean-Proterozoic ter- rains in Central and Northern Brazil. The quartz boudins in Al rich schistose rocks and the weathered and chemically enriched

Jan 1, 1988

By S Vink, V Nanjappa, C J. Moran

Poor quality water resulting from interaction of surface run-off with saline mine spoil and soils can cause significant problems for water reuse on mine sites. Not only can this saline water lead to machine corrosion and increased maintenance costs, but may cause detrimental effects on the environment. Determining the geochemistry of mine spoil, and the likelihood of salt dissolution during rainfall events, may aid in more effective mine site management of water. Spoil samples were taken from three areas of the German Creek mine site, situated in the Bowen Basin coalfield, Queensland. Samples from two undisturbed areas on the lease were also collected for comparison. Analyses were performed using a variety of laboratory techniques: leaching tests, effective cation exchange capacity determination, X-ray diffraction, clay quantification, and total organic content determination. Results show that dissolution of surface (top 2 cm) salt minerals from spoil areas is an important contributor to surface run-off salinity during rainfall events. Equally, ion exchange with clay minerals appears to be a significant source of elevated ion concentrations in run-off waters. Findings from the undisturbed areas show undetectable quantities of salt mineral species, resulting in waters with low ion concentrations. More generally, monovalent cations (sodium, and to a lesser extent potassium) appear to be derived from dissolution of salt precipitated whereas divalent cations (calcium, magnesium) are more likely to be sourced from exchange reactions with clay minerals. Incorporating knowledge about the mechanism of cation mobilisation from spoil with the spatial distribution of spoil properties and understanding of the dynamics of water quality variations on the site will aid in development of integrated water quantity and quality management strategies.

Jan 1, 2009

By G M. Evans, C M. Phan

This paper presents an analysis on the dynamic adsorption of frothers and collectors onto air bubbles in flotation. The analysis was carried out using the theory on the surfactant transfer by diffusion and adsorption. The bubble size was considered when solving the diffusion equation for the dynamic surface excess. The adsorption kinetics was modelled employing the Langmuir adsorption isotherm and its extension with the inclusion of the lateral interaction of the adsorbed molecules (the Frumkin adsorption isotherm). The numerical computation was applied to solve the governing equations. The dynamic adsorption of the surfactants was measured in terms of the dynamic surface tension for sodium dodecylbenzene sulfonate (SDBS) and Dowfroth 250, using pendant bubble tensiometry. The results show that for air bubbles with diameter of the order of 1 mm, the bubble size effect on the dynamic surface tension is small and the solution of the diffusion equation for a planar gas-liquid surface can be used to describe the dynamic adsorption onto the air bubbles. The experimental data obtained with SDBS were well described by the Frumkin adsorption isotherm and the molecular diffusion. The model description for the experimental data obtained with Dowfroth 250 required the kinetic equations. The paper is relevant for further analysis of the role of the adsorbed surfactants in the particle collection.

Jan 1, 2005

By J Rayner, R P. Langmead, J A. R Coote

Gosowong is situated within the Neogene magmatic arc of Halmahera island in the Maluku province of eastern Indonesia. It was discovered as the result of a rigorous ground reconnaissance program in an area with no previous mining activity. The broad structural setting in the Gosowong District comprises an elongate dome formed by the forceful upward intrusion of magma along a deep-seated structure, resulting in associated tensional fracturing trending parallel to the long axis of the dome. Four copper-gold porphyries and numerous low-grade epithermal veins occur within this mineralised corridor, with the Gosowong Deposit being the only economic occurrence discovered to-date. Gold mineralisation is hosted within multiphase epithermal quartz-adularia and quartz-chlorite fissure veins, breccias, and stockworks. High-grade gold mineralisation is emplaced in two gently south-plunging ore shoots along a 400 m section of the north-striking, east-dipping, Gosowong Fault, the primary control on mineralisation. The Gosowong Fault is believed to be a tensional fracture associated with uplift of the dome. Lithological variation and structural intersections play a large role in grade distribution within the vein zone. Host rocks comprise a wide range of shallow marine, intermediate-basic volcanic and volcaniclastic rocks of ?late Miocene age. The Gosowong gold deposit is a classic example of a low-sulphidation epithermal gold deposit, based on the abundance of adularia and illite in the alteration assemblage, and low base-metal sulphide content within quartz-adularia veins. The indicated resource is estimated at 0.99 Mt at 27 g/t Au and 38 g/t Ag for a total of 870 000 ounces Au, using a cut-off grade of 2 g/t Au.

Jan 1, 1999

By C Preston, T Williams, D Roy

The easiest way to mine valuable orebodies is through the use of explosives and well-planned blasting layouts that produce fragmentation profiles designed specifically for conveyance equipment in underground mines. The design of blasting patterns is specific to not only the explosives being used but also the rock or ore type being fragmented. Many blasting designs are based solely on the experience of those developed for similar orebodies in terms of properties and orientation or individuals that have some blasting experience.The primary technical objective of this paper is to outline a unique methodology for determining underground blasting methodologies (developing specific blasting parameters) commensurate with explosive energies and rock/ore equations of state for a narrow-vein gold property located in Northern Quebec and for underground mines in general.The procedures developed are to define the desired fragmentation specification so that a specific thermodynamic break is generated, taking into account powder factor, energy factor, tonnages, explosive energies and distribution along with blasthole diameter and orebody orientation for a specific set of explosive and dynamic rock/ore properties. Determining dynamic modulus values for the ore using seismic sensors to measure P- and S-wave velocities, the aforementioned parameters will be utilised to set the design constraints to maximise recovery and minimise overbreak and dilution.New underground blasting software (AEGIS) will use thermodynamic break in conjunction with defined fragmentation profiles to create an array of blasting parameters used to design and plan ring layouts. This software will also allow mining planners, prior to drilling and loading a production blast, to appraise future intended blasting patterns to minimise the potential of diluting ore with host rock and the likelihood of damaging mine support structures.CITATION:Roy, D, Williams, T and Preston, C, 2015. Underground stope drill and blast designs optimisation program, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 137–148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By N Power, A D. Costar

There has been significant growth in mining and energy exploration in South Australia, which has identified new major potential opportunities. This sector generates significant economic value to the state and their support remains a priority for the state government. The delivery of this economic and associated community value to the state is dependent on the mining and energy sector being able to access reliable water supplies.The vast majority of priority areas for the mining and energy sectors are located in areas that have traditionally been of low priority from a water-use perspective and hence, data and knowledge levels are generally low.Recent studies have identified a potential increase in demand for water in the mining and energy sector for potential developments from approximately 40 GL to over 170 GL over the next ten years. The studies found that water and water infrastructure is the second highest proportion of planned infrastructure capital investment by resource companies. The South Australian GovernmentÆs Plan for Accelerating Exploration (PACE) initiative (PACE 2020), also identifies addressing the issues of location, use and management of South AustraliaÆs water resources as a key priority for the growth of the mining and energy sector.The Department of Environment, Water and Natural Resources (DEWNR) has developed the facilitating long-term outback water solution (FLOWS) initiative. DEWNR is currently undertaking a suite of programs to provide groundwater information at the regional scale to better target water supply options for mining and energy developments and community water supplies.The Goyder Institute for Water Research has leveraged significant research investment of $3 M to develop methodologies to interpret airborne geophysics to map groundwater sources.The FLOWS Initiative will provide key content for the PACE Water Program and will also assist in the development of water supplies for remote far north communities by identifying alternate groundwater sources to improve water supply security.This paper will discuss how developing an appropriate science and knowledge base will encourage and secure development where appropriate, enable prudent decision-making and policies regarding water allocation, accounting and licensing, whilst ensuring the protection of environmental assets.CITATION:Power, N and Costar, A D, 2013. Finding long-term outback water solutions, in Proceedings Water in Mining 2013 , pp 191-196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By R L. Verburg, R Johnstone

DeBeers Canada Mining Inc (DeBeers) recently submitted an Environmental Assessment (EA) for its proposed Snap Lake Diamond Mine located in Northwest Territories, Canada. As part of the EA process, a site water quality management plan must be developed. Plan development requires an integrated approach such that the key factors influencing water quality can be identified and managed to minimise potential impact. A system model was therefore developed to simulate the site-wide water quality conditions and mass loadings to the principal environmental receptor of concern, Snap Lake, during operations and post-closure. Requirements of the simulation included integrating hydrology, geochemistry, hydrogeology and site management practices in a dynamic way. A unique feature of the site was the need to accommodate a complex flow system that included a feedback loop between lake water and mine water. A system model was constructed using the GoldSim software package that integrated on-site water quality and flow measurements, as well as results from independent groundwater flow and geochemical modelling efforts. The GoldSim model simulated concurrently the movement of 39 solutes through the subsurface mine and surface facilities. Solute sources considered included four different waste rock and tailings types, explosives use in the mine, treatment plant discharge, and recycled process water for dust suppression. Separate solubility constraints were identified for different regions of the flow system (eg underground mine; treatment facility; surface water bodies). Kinetic test data were used to derive temperature-dependent rate constants for use in calculating mass inputs from surface sources such as waste rock piles. The model generated water quality estimates over time for a variety of management scenarios at several potential discharge locations. The integrated approach used by the model was effective in identifying the significance of key factors influencing overall water quality such as explosives use, mine water inflow rates, waste rock reaction rates, site/mine management options, and effectiveness of treatment. The model provides an example of an effective tool for comprehensive, integrated system evaluation and management.

Jan 1, 2003