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By John W. Scott

INTRODUCTION The design criteria for a particular concentration and dewatering project will provide the formal basis for design of the process, equipment and facilities. These criteria will specify the required capacities and operating schedules for the equipment, as well as the quantity and quality of the feed to be processed and products obtained. The general climatic and geographical conditions at the site, specific information on soil or rock conditions; and applicable design standards and codes will also be included. The design criteria will generally be based on an interpretation of testwork carried out on the particular ore and site, and will thus parallel in detail and completeness this testwork. As the project moves from the early conceptual phases through to final detailed design, the design criteria will be developed and become more detailed as information is generated and made available for use. The design criteria are critical to the design effort as the formal specification to the designer of what and how much is to be processed, what and how much is to be produced, and where and under what conditions. The actual design criteria will be a formal tabulation of the design basis information developed for the project in question. For a preliminary study, this may consist of a single page of data; for a feasibility study several pages and for a detailed design up to several hundred pages and multiple volumes. Depending on the complexity of the process and the level of detail included, each project will be unique to some degree. The design process for a project normally progresses from preliminary conceptual phases through to a final detailed design. The criteria used for the initial concepts are generally developed from rough data and preliminary testwork on the ore in question. Regardless, the plant throughput and products are defined, thus giving a scope and definition to the study phase. In some studies a range of throughputs may be analyzed in order to arrive at the most economically attractive size for the proposed operation. This optimum size is then used as the design throughput for the more detailed design phases. Similarly as more testwork results are available and the ore characteristics and process become more well defined a continuous updating of the design criteria is undertaken.

Jan 1, 1986

By Bruce Kennedy, Dan Nilsson

Mining means drilling and blasting in order to break down the rock, loading and transport, and often also crushing the ore down to a suitable size. These operations can be done in open pits or in underground mines, and also, to a lesser extent, in marine mining. The same operations are also used in various types of construction, i.e., for roads, water power stations, etc. Before beginning a detailed economic analysis of the factors which enter into deciding whether to mine by open-pit or underground mining, and at what point a change should be made from open-pit to underground mining, or vice versa, it is of interest to consider some general factors.

Jan 1, 1982

By M. Guzman, M. Romero, S. Bravo-Thais, M. Flores

The phytoremediation method is proposed to recover valuable metals from polluted soils. In this sense, the objective of this research is to determine if it is possible to use native plants in the recovery of precious metals from abandoned mining liabilities. The tailings samples containing Au and Ag were acquired from the northern region of Peru. Two native plant species, Stipa Ichu and Cortaderia Nitida, were used. Results show that Au was recovery around 19% (1.52 mg/Kg) and 25.43% (1.78 mg/Kg) by using Stipa Ichu and Cortadeira Nitida, respectively. Besides, Ag had a better recovery in the Stipa Ichu reaching a value of 6.83% (0.628 mg/Kg); in contrast, Cortadeira Nitida had an efficiency of 3.6% (0.814 mg/Kg). Bioaccumulation, bioconcentration and translocation factors were calculated by determining the concentration of precious metals in the roots and aerial parts of each plant. Results show that Stipa Ichu had a greater capacity of hyperaccumulated Ag compared to Au; while Cortaderia Nitida tended to have a better performance for Au. In conclusion, both plants are recommended for phytoremediation of mining liabilities.

Feb 1, 2023

By Ezra L. Kotzin

Foundry sands used to make molds and cores have been very important to foundrymen since metal casting began hundreds of years ago. They are now used in two basic ways, either in an uncured green state, grain-bonded with clay, or in a set cured state achieved with sand that, mixed with resins or oils, is cured by baking or by chemical reaction. The term sand, as generally used in foundry applications, may best be defined as material composed of granular particles of mineral matter, ranging in size from 0.5 to 2 mm in diameter. The particulate nature of the material may be the result of natural disaggregation or result from crushing and screening of rock or ceramic materials; crushed and screened products are sometimes referred to as "manufactured sand." Based on their origin, the raw materials for foundry sands will vary in grain shape, grain composition, relative surface, grain size, and grain distribution patterns. These properties, in addition to their chemical analyses, sintering point and expansion characteristics play an important part in the choice of sands used as the base molding or core aggregate in metal casting. Sands with different origins may be blended to produce specific compositions and grain size distributions. Early raw material requirements based on silica sand were simple, but as sand/core/mold technology became more sophisticated and binder technology continued to be developed, the physical properties of foundry sands became more critical. Silica sand is composed of quartz, along with, in most cases, small amounts of feldspar, mica, clay, and other common minerals. Although silica sand is still by far the most widely used base material in production of molds and cores used in metal casting, other natural mineral sands have their own unique characteristics and fill an important niche in special applications. As a result, the term sand, as applied to raw materials used in metal casting, has been logically extended to include granular materials composed of a group of minerals other than quartz. With increased use in advanced foundry technology, natural sands composed predominantly of zircon, chromite, staurolite, or aluminum silicate minerals and of granularized chromite or olivine, have become more than just alternate materials and are now commonly classified as sands when the grains are sand-sized. Foundry sand may therefore be considered under two categories: silica sands and non-silica sands.

Jan 1, 1994

By H. K. Lin

Elemental sulfur is founded to be the predominant sulfur-containing species in a leaching residue resulting from ferric chloride leaching, under given conditions, of a chalcopyrite concentrate. The mineralogical study of the leaching residue which consists of 52% elemental sulfur reveals that the sulfur formed at the end of leaching process is in the form of discrete crystal rather than coating film. Flotation has been applied to recover the sulfur successfully using xanthate as a collector. Dispersants arc needed to prevent the mechanical entrapment of silicate and quartz by sulfur. Very high recovery of sulfur with satisfactory grades can be achieved with a relatively simple notation scheme.

Jan 1, 1991

By T. C. Rao, N. Suresh, M. Vanangamudi

Experiments have been conducted on a 76¬mm water-only cyclone treating cowl below 2 mm size having different proportion of -0.075 mm fines. The effect of cone angle of the cyclone (compound cone) has been analyzed on water split, separation of -0.075 mm fines, separation of coarse solids, and on separation behavior of individual size ructions of the feed. It has been noted from the results that there exists a linear relationship between the flow rate of water in the feed and flow rate of water reporting to overflow stream. This relationship is independent of the cone angle and, with changes in the fines content in the feed, only the intercept of the straight varies, keeping the slope constant. Further, it has also been found that the percentage of fines below 0.075 mm reporting to the overflow is directly proportional to the percentage of feed wafer reporting to the overflow. This relationship is found to be independent of the cone angle and the fines in the feed. The performance of the water-only cyclone has been analyzed by plotting partition curves for different experimental conditions. In addition to this, the Rosin-Rammler equation has been fitted to the partition curves of the hulk feed and individual size-fractions. Tile analysis of the results has revealed that the specific gravity of separation increases with increase in the cone angle of the cyclone while it decreases with increase in percent fines present in the feed. Mathematical relationships have been developed to relate the variation in SG50 with cone angle and percent fines in the feed.

Jan 1, 1990

By J. C. Purcupile

In this time of increased coal demand, a faster and safer method for roof support is needed. This report outlines the preparation and testing of a machine which we feel will help answer this need. The results of the tests are encouraging, and indicate that further exploration of the method should be continued.

Jan 1, 1975

By F. A. Aplan, Richard R. Klimpel

This article discusses the role of mathematical optimization techniques as applied to the design and analysis of particulate processing plants. The emphasis will be placed on the macro engineering view of integrated multiple operation plants such as those that typically involve stages of size reduction, sol id-sol id separation, solids storage, chemical reactions involving sol ids, sol ids disposal, etc. The macro engineering view is chiefly concerned with balancing and optimizing the bigger picture of how various unit operations interact technical and economically with each other in an approximate sense rather than how a specific unit operation can be technically described and optimized in detail (micro engineering.)

Jan 1, 1991

By T. Shungu, N. Vermaut

The various copper-cobalt ores mined by Gecamines, together with typical plant applications and results, are briefly described. Intensive laboratory investigations have been undertaken in recent years to improve the metallurgical performances of the various concentrators. As a result of these tests, it was shown that the flotation of the siliceous oxide ores could be improved by increasing the efficiency of the palm oil collector (energetic conditioning, chemical emulsifier, petroleum sulfonate addition) and by varying the froth depth in the cells. A new flowsheet incorporating these modifications and a regrinding stage has been approved for the rehabilitation of the Kolwezi concentrator. For what affects dolomitic oxide ores, hydroxamates were tested as secondary collectors and, based on successful laboratory results, plant trials were run but failed due to excessive frothing. In other plant tests, xanthates were replaced by a xanthate- fatty acid mixture; plant trials over more than one year proved successful for copper, but not for cobalt. Mercaptans were tested as secondary collectors for the sulfides flotation from sulfide or mixed oxide-sulfide ores; laboratory results proved successful but, to date, no plant test has been run.

Jan 1, 1987

By Allan D. Fernie

Growing interest in pit crushing and conveying is evident from the many articles, technical papers, and new equipment development recently presented. Application of a pit crushing and conveying system is complex, as many factors such as mine design, production scheduling as well as initial and ongoing capital and operating costs must be thoroughly and realistically examined. This paper will address the fundamentals to be considered and review several approaches to developing a total system for a new and existing mine situation. The planning function will be outlined and operating and design criteria defined to interface the mining operation and the pit crushing conveying system.

Jan 1, 1983

By Spencer R. Titley

The subject of this lecture, a late century perspective on porphyry copper geology, is one of current interest and importance as the search for these ores remains intense. It is presented in the belief that an appreciation of our present understanding of the subject requires it to be viewed historically, thus providing a basis for evaluating appropriate directions for con¬tinued study. At the outset, it is important to note that the technology of mining and extractive metallurgy has developed ore from these low grade orebodies, starting with D. C. Jackling, and has continued to create them as copper grade and price have diminished. But the continued search for them is a geological problem that responds to growing expectations of people and societies; exploration based upon ever increasing knowledge of the habits of the ores has been very successful. This is the story of evolution of geological thought and practice in porphyry ore search across an interval of time beginning with the bulk mining of "low grade copper ores at Bingham and ending with late Century concepts. "How did we get here?" The lecture concerns the ideas of many different people. The ideas and events discussed reflect a bias on North American thought, where the great low grade orebodies were first recognized as such and where many of the basic geological ideas were developed. A very great number of geologists have contributed to this understanding. In no sense is it meant to minimize the contributions to the story that have evolved in the study and mining of ores of the Andes, whose development and expansion has been nearly synchronous with that in North America - nor to minimized comparable contributions made in the late century from studies of the newer discoveries of deposits in other regions, especially the southwestern Pacific regions. In expansion of this topic, I have found that many important concepts are marked by appropriate publication but some are not, or I have not been able to discover documentation. Many notions appear to have become conventional knowledge without publication, mostly being geological viewpoints developed synchronously from similar observation. Thus, apologies are extended in advance to those whose work I have might have missed and to those unknown to me whose unpublished ideas may have seeped into the pool of common knowledge without appropriate recognition. . The analysis here addresses events of two time segments, an older one extending from the developments at Bingham in the early 1900s through the Second World War, ending about 1950; the second period extends from that time to the present. This separation is seen in Figure 1, which traces numbers of publications through the period as extracted from some 700 publications, again with a North American bias, from an annotated bibliography of porphyry copper geology in preparation. During the early period, exploration was "immature" in North America, that is, geologists looked for new districts and sites of the deposits. Outcrops were sought that carried the signatures of former mineralization and regional controls related to structural geology were closely studied. In the later period, North American exploration had "matured" into a study of districts, rather than a search for them. As the studies of these ores intensified during the younger period concommitant with increasing demands for the metal, they did so with a broadened understanding of some habits of occurrence, of hydrothermal alteration, mineral zoning, petrology, and geochemical and geophysical signatures. Outside of North America, search remained "immature" but closely related to the

Jan 1, 1997

By D. C. McDonald, P. R. Whincup, H. Duke

Due to grade, overburden depth and stability and the presence of groundwater it was considered impractical to recover gold contained in unconsolidated palaeochannel sediments by conventional mining, dredging or borehole mining techniques. A series of field experiments was conducted to determine the feasibility of recovery of gold by in situ leaching from sediments located at a depth of about 80 metres. The test wellfield site and plant are described together with field test procedures, results and wellfield rehabilitation procedures. Choice of sodium cyanide as leachant and laboratory testing are discussed in relation to groundwater and sediment chemistry and problems encountered in field tests.

Jan 1, 1989

By Paul I. Eimon

Mineral exploration involves the selective collection, organization, evaluation, and interpretation of geologic and economic data. The sources for such data are original field observations and existing documented information of various types (publications, reports, maps, company files, etc.). As exploration data are accumulated, their storage, organization, indexing, and J retrieval is key to exploration progress. Initial use of computers by mineral exploration groups indicates that data can be meaningfully handled by machines. A computer system makes possible: 1) the storage, manipulation, collation, and selective retrieval of data; 2) the utilization of data banks developed by geologic service groups and available at relatively low cost; and 3) the retrieval of stored data more rapidly, completely, and effectively than by manual systems. Profitable utilization of these capabilities is conditioned by several factors, particularly by the information selected for the system data base and by the design of the computer system itself.

Jan 1, 1968

By Patrick Corser, Mitch Usibelli

Introduction Coal mining in Alaska's interior, specifically in the Healy area, began as early as 1918 with the construction of the Alaska Railroad. Mining was originally limited to underground operations but has expanded to entirely surface operations. In 1943, the Usibelli Coal Mine was formed and started developing Alaska's first surface mine east of Suntrana (Usibelli Coal Miner, 1984). Production from the local coal deposits has steadily increased and, in 1978, surface mining of Poker Flats was initiated (Fig. 1). Currently, a 25-m3 (33-cu yd) walking dragline strips two coal seams, using an extended bench on the second pass. In addition, a fleet of trucks and shovels are used for coal removal and some limited overburden stripping. In 1984, a contract was signed between Usibelli Coal Mine and Sun Eel Shipping Co. in 1984. Since then, production has nearly doubled to more than 1.3 Mt/a (1.5 million stpy). This article will discuss geotechnical constraints on mining within the steeply dipping coal deposits that exist within the Poker Flats mining area. Specifically, the article will describe how the mining operation retriggered an historic landslide on the No. 5 coal seam (Fig. 2). And the article tells how a mine plan was developed that allowed the coal to be safely removed without inducing additional movement. Regional geology The coal-bearing group in the Nenana coal field is of Tertiary Age. It is overlain in some areas by several thousand feet of Tertiary gravels - the Nenana Gravels. In areas mined by surface methods, the Nenana Gravels have been eroded off, and up to 30 m (100 ft) of quaternary outwash gravels overlay the coal-bearing formations. The coal-bearing group is divided into five formations: Healy Creek, Sanctuary, Suntrana, Lignite, and Grubstake (Wahrhaftig, 1969). Lignite Creek lies on the north limb of a west plunging anticline. This has brought the Suntrana coal-hearing formations near enough to the surface to allow surface mining. Mining is presently in progress on the south side of Lignite Creek in the Poker Flats area. The coal-bearing formation is cut off to the south by a fault having perhaps several thousand feet of vertical displacement, with the upthrust side to the north. South of this fault, Nenana Gravels are exposed on the surface. The Suntrana Formation contain the minable reserves at Poker Flats. This formation is a repeated sequence of poorly consolidated pebbly sandstone near the bottom, grading through a silty fine sandstone to a footwall clay unit immediately below a coal seam cap. The footwall clays are high plasticity clays to silty clays. It has been reported that they contain 30% to 50% montmorillonite (Usibelli Coal Mine Inc., 1982). There are six coal seams in the Suntrana Formation, No. I (the lower seam) through No. 6. Only the top four seams are currently exposed. No. 3, No. 4, and No. 6 seams are the only mined seams. The No. 5 seam is very thin or not present. Portions of the undisturbed Suntrana Formation are overlain by up to 15 m (50 ft) of Quaternary outwash gravels or recent landslide rubble. The surface is overlain by a very thin layer of muskeg and isolated areas of permafrost. In many areas, the outwash gravels are found immediately below the surface muskeg. Numerous landslides have been documented along the north facing slopes of Lignite Creek (US Geological Survey, 1970, and Wahrhaftig, 1958). These appear to be surficial solifluction or skin flow types of landslides. In addition, deep-seated structurally controlled slides are also evident on both the north and south sides of Lignite Creek. Structural features Premining aerial photographs (Fig. 3) of the Lignite Creek slopes in the Poker Flats area indicate substantial evidence of deep-seated landsliding. The landslides noted in Fig. 3 are both inside and outside of the current mining area. Surface mapping and geologic exploration indicate that the coal seams are dipping out of the slopes within the noted slide areas. It is suspected that, historically, these landslides were triggered by undercutting of the toe of the slopes by Lignite Creek. And sliding it thought to have taken place on one or more of the clay beds underlying the coal seams (Golder, 1985). The slide areas are characterized by semicircular head scarps and slumped topography. Based on the premining photographs, these slides do not appear to have been recently active. However, they are expected to be in a state of only marginal stability. Extensive coal exploration indicates that the primary structural feature within the

Jan 1, 1989

By Robin J. Batterham, Stephen H. Algie

It is often stated that innovation is central to the economic survival of mining and mineral processing in the face of global competition, and yet technology is often far from a core strategy in our industry - hence the concerns that are often voiced about the apparent slow rate at which new technology is applied. Much of the discussion stems from a lack of understanding of the role of technology in innovation, and of the role of R&D within the innovation process. To a large extent this has all been said, however, the messages are clear and deserve repetition. This paper expresses the personal views of the authors, based on experience in government-funded (CSIRO and universities) research, and in CRA Ltd, a large mining and mineral processing company. Further than this, it explains how our own development unit within the CRA Group has come to see its key roles as including the transfer of technology, and the training of technologists to move into the operating business units. We conclude that these critical tasks are the keys to creating the environment that will allow us to maximise the contribution of technology.

Jan 1, 1995

By Jacob L. Brinkman, Catherine E. Johnson

Unmanned aerial vehicles (UAVs) are being explored by researchers to measure concentrations of gas emissions in situations where such measurements are otherwise extremely difficult to obtain, such as NO and NO2 (NOx) emissions from surface mine blasting. Recently, countries have imposed or are planning to impose surface blasting gas pollution regulations, which creates a need for an improved understanding of UAV-based gas measuring systems. The experiments detailed in this paper were performed to determine if airflow generated by the rotors, also known as downwash, unnaturally alters concentration measurements. Downwash turbulence could create locations of varying pressure, which could affect concentration. A UAV fitted with gas sensors was attached to a stand in a controlled environment containing a mixture of NOx. The gas sensor measuring points were placed at various distances on and from the UAV body to evaluate downwash effects on gas concentration. Results show that the presence of downwash turbulence causes no statistically significant changes to concentration measurements at any distance or direction from the UAV. Based on these results, it is possible to use a UAV-mounted gas monitor to measure concentrations without concern for downwash interference, provided the UAV and measuring point are entirely contained within the gas cloud.

May 20, 2021

By S. Tuylu, D. Adiguzel, A. Bascetin, O. Ozdemir, U. Cinar

"In recent years, use of mineral processing tailings as a paste backfill has been significantly increased due to the environmental problems occurred during the disposal of the tailings in mine area. The paste material used to fill the stopes excavated is generally consisted of tailings (solid ratio: 70–85%) and cement (3-7%w/w). Meanwhile, the strength of the paste material is completely related to ratios of these materials. Cemented Paste Backfill (CPB) system is used as support depending on the roof pressure and also as an underground disposal method. Therefore, temporary strength value of the paste material gains a great importance. For example, the paste backfill material must compensate the minimum 4 MPa strength value in order to procure the permanent fortification, and the mixture cost must be minimal as well. For this reason, in this study, the Pb-Zn tailings were used to prepare for the paste backfill material using cement in order to perform the uniaxial compressive strength (UCS) tests. Additionally, a statistical experimental design and linear programming techniques was used to find the optimum mixture in terms of strength and cost. The pulp solid ratios (PSR) of the tailings and cement (by the solid) were varied as 75-85% and 3-8%, respectively. The results of this study; the optimum mixture is ~79.5%PSR and 6.8% cement ratio (by the solid) for 4 MPa UCS (28 day) and 16-17 cm slump value determined by this method with statistically reviewed experimental data. INTRODUCTION Fine-grained tailing waste materials resulting from mining activities are an important environmental problem. In terms of environmental protection, the use of tailings with paste backfill is a very attractive approach and a desirable solution to tailings management. Paste backfill, which is used to fill underground openings, is made by primarly mine tailings mixed with hydraulic binders and water. Its main benefits are not only disposal of mine tailings in underground, but also providing a certain strength to ensure a safe working environment. Therefore, it is necessary to use hydraulic binders due to durability of the system (Benzaazoua et al., 2004). Paste backfill, formed from the mix of dewatered plant tailings (75-85 wt. % solids), water and binder (3-8 wt. %) (Brackebusch, 1994; Landriault et al., 2005).Water is used to determine the chemical reactions between tailing and binder materials for strength as well as increasing pumpability. Portland cement and ash can be used as binder materials (Douglas and Malhotra, 1987). The factors which affect strength and stability of paste backfill separate into two groups called interior and exterior factors. Interior and exterior factors determine the strength, stability and deformation features of backfill in short and long terms and also affect the transportation of backfill to underground (Benzaazoua et al., 2004; Erçikdi et al., 2006; Yilmaz et al., 2010; Nasir and Fall, 2010). Material properties of tailings as well as site operations to fill the underground openings are the most important steps for the design purposes. Grain size distribution, chemical, and physical properties of tailings, and mechanical properties of paste fill material are used to understand the suitability of tailings as paste fill material (Ozturk et al., 2014). In addition, Fig. 1. is also proposed to apply a typical design for the operational stages of paste fill applications on the site."

Jan 1, 2016

By Dmitriy A. Malovichko

The general theory for the description of seismic sources is briefly discussed. The effect of excavations on seismic radiation is considered. Expressions for seismic source mechanisms in terms of the geometrical and mechanical parameters of source processes are provided for the following cases: fault slip and shear failure in a confined environment, dynamic stress fracturing around a tunnel, rock fall, landslide and sudden subsidence. A classification of seismic events in mines based on source mechanisms is introduced. The classification separates blast-, slip- and crush-type events. Various approaches of analysis of source mechanisms involving forward modelling and inversion are discussed. The following examples demonstrating the utility of source mechanisms in mining are presented: forensic analysis of damaging seismic events, assessment of the increase in the depth of failure for dynamic stress fracturing around tunnels and its duration, examination of the rockmass deformation regime, assessment of deformation around tunnels using crush-type events, identification and parameterisation of weak geological structures, stress inversion from slip-type events. Finally, the requirements for seismic data to ensure high quality source mechanism solutions are briefly reviewed and future challenges in the interpretation and utilisation of seismic source mechanisms in mines are speculated on.

Apr 26, 2022

By Charles Kocsis, Pedro Nascimento, W. Patrick Arnott, Samuel J. Taylor

Respirable crystalline silica (RCS) is an inhalation health hazard for mining and industrial work environments and must be monitored. We provide theoretical analysis of real-time measurements for determining RCS mass concentration without the use of filters by using photoacoustic spectroscopy. The suspended dust in the mine air can be continuously sampled by the photoacoustic instrument. A tunable quantum cascade laser is the light source, allowing for determination of interferences such as kaolinite, coal dust, and water vapor. The most useful spectral region is found to be between 11 and 13 μm. Absorption by water vapor, and, to a lesser extent, carbon dioxide, in this spectral region has gaps that allow for quantification of the aforementioned dust species as well as a convenient check on the calibration of the instrument. This work brings photoacoustic measurement of aerosol to the mid infrared range where spectrally dependent light absorption can be used to quantify dust composition and mass concentration.

Jul 31, 2022

By J. Loredo

Wastes related to abandoned mine sites can constitute important potential pollution sources, depending on their mineralogical and geochemical characteristics and volume. Mine waste disposal sites contain a diverse variety of wastes including overburden material and waste rocks, the ore which cannot be economically removed and wastes from the smelting processes when they are accomplished at the mine site. These materials are usually heterogeneous in size, mineralogy and metal concentrations. Asturias, in northern Spain, has an extensive mining history and, in consequence, there are abundant unreclaimed and derelict mine sites with abandoned mines and spoil heaps of different age, morphology, content and dimensions. In these spoil heaps, waste materials are subjected to the intense action of a humid environment, so the instability of sulphides and sulpharsenides results in the production of acid and metal-rich leachates, which are incorporated to surface water or infiltrated through the land reaching groundwater bodies. The mineralogical and geochemical characteristics of the stored materials are key data to evaluate if they represent an environmental risk. Mineralogy and geochemistry of wastes and the particular specific environmental conditions of each site affect the rate of weathering and therefore the metal release. The characterisation of mine wastes is a necessary step in order to establish suitable assessment strategies with the aim of reducing the leaching, transport and widespread of ecotoxic elements from mining wastes to the environment (surface water, sediments, soils and air). As a consequence of the weathering of As-rich mineral phases, high arsenic contents are commonly detected in effluents from mine voids and spoil heap leachates.

Jan 1, 2006