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Samples collected during the exploration phase of mining represent baseline conditions at the site. As such, they can be very important in forecasting potential environmental impacts should mining proceed, and can become measurements against which future changes are compared. Constituents in stream water draining mined and mineralized areas tend to be geochemically, spatially, and temporally variable, which presents challenges in collecting both exploration and baseline water-quality samples. Because short-term (daily) variations can complicate long-term trends, it is important to consider recent findings concerning geochemical variability of stream-water constituents at short-term timescales in designing sampling plans. Also, adequate water-quality information is key to forecasting potential ecological impacts from mining. Therefore, it is useful to collect baseline water samples adequate for geochemical and toxicological modeling. This requires complete chemical analyses of dissolved constituents that include major and minor chemical elements as well as physicochemical properties (including pH, specific conductance, dissolved oxygen) and dissolved organic carbon. Applying chemical-equilibrium and appropriate toxicological models to water-quality information leads to an understanding of the speciation, transport, sequestration, bioavailability, and aquatic toxicity of potential contaminants. Insights gained from geochemical and toxicological modeling of water-quality data can be used to design appropriate mitigation and for economic planning for future mining activities.

Jan 1, 2011

By Liu Cheng-si

Basing on a brief assessment of the conventional theory of ventilating air distribution, its methods of calculation and practical application, this paper makes an approach to the controllability of different aircourses of a ventilation network and further points out that it is possible for the positions of control to extent into the natural distribution subnetwork of the ventilation network, which was been long considered as a restricted zone. This important discovery makes the regulation of the ventilation system more flexible and diversified, thus attaining quantitative distribution of ventilating air as well as a cost benefit. Because it has been impossible to solve the problem mentioned above by conventional theory and its relevant methods of calculation, the author, based on applying graph theory on the structure, characteristics, and requirements of controllability of the ventilation network, presents a new controllable subgraph concept and the means for determining the rational quantity for control devices of the ventilation network. The solution of all the control alternatives and methods of obtaining all the parameters for the solution of various alternatives have been derived. The economic benefit and the optional positions of the control devices have also been approached. Specific calculation examples are a1 so included in this paper. Along with the conventional theory and its methods, it can be seen that the new theory presented makes a great change in the control aspects of the ventilation network, with the number of possible alternatives increasing in an astonishing manner. Among the alternatives, some may be safer, more economical or technologically superior than those obtained from conventional theory. Thus, the new theory may provide an immense improvement in the choice of a ventilation system.

Jan 1, 1987

By James R. Miller

Recent experience over extensive areas of the Basin and Range Province has demonstrated the importance of the basin's (valley's) geology and geomorphology in locating large quantities of good-quality aggregate. First, a geologic map depicting basic geomorphic-geologic units in a valley is made in the office from aerial photography. Next, derivative maps are made from geologic maps and field-derived information such as parent rock type, source area and depositional environment, relationship to adjacent deposits, and Quaternary geologic history. Studying the derivative maps leads to selection of test sites for potential deposits of high-quality aggregates. Subsequent field studies provide more detailed information about geologic processes and samples for laboratory testing. Combining all information allows the characterization of aggregate potential of very large areas. Favorable areas can be further tested. This phased approach has proven to be cost effective. The methodology used in mapping and characterizing basinfill deposits is applicable over much of the western United States. Map units were developed by focusing on the predominate geomorphic process, grain size, cementation, and relative age. The resulting functional map units are of use to engineers and planners. This study led to many conclusions, including the fact that the best quality basinfill aggregates are found in selected alluvial fan deposits and Pleistocene lakeshore deposits. The best quality aggregates are derived from Paleozoic carbonate and quartzitic parent materials that can also provide high-quality crushed-rock aggregates.

Jan 1, 1987

By Antonio Nieto, Jesus Castillo

Research and Development (R&D) departments in the mining sector are essential for creating new solutions on productivity, safety, and sustainability. Nevertheless, the selection of R&D projects is complex, often influenced by subjective judgments and uncertainties. This paper explores the application of the Multicriteria Decision Analysis (MCDA) as a structured approach to evaluate and prioritize innovation projects based on various criteria such as safety, cost, environmental impact, and social acceptability. By assigning weights and quantifying criteria, MCDA enhances decision-making transparency and objectivity. This study aims to show a method that facilitates strategic thinking, resource optimization, and stakeholder engagement, ensuring that selected innovations align with the company’s long-term objectives and commitment to responsible mining practices.

Feb 1, 2025

By J. J. Davis, C. A. J. Fletcher, M. Li, T. Jancar

This paper summarises the experimental approach to spiral modelling at the Julius Kruttschnitt Mineral Research Centre, University of Queensland, involving the use of plastic density tracers to determine partitioning performance on three models of coal spiral. This work has led to phenomenological models of the three spiral profiles most widely used in the Australian coal industry. The results from a parallel computational fluid dynamics approach to spiral modelling currently underway at the University of New South Wales are also presented. The computational simulation has been successfully applied to generic spiral geometries and is capable of predicting the fluid phase three dimensional flow fields and corresponding free surface profiles for moderate Reynolds' number and Froude numbers. Simulation predictions are compared with experimental results from a Mineral Deposits LD9 coal spiral.

Jan 1, 1995

By M. T. Worley

Joint Development Associates International, Inc. (JDA) began humanitarian relief and community development in Central Asia in1992, following the collapse of the former Soviet Union. Appropriate technology has played an important role in their efforts to assist those segments of society that are most vulnerable to poverty and disease. Three case histories are described to illustrate the successful implementation of simple, but effective technology in community development.

Jan 1, 2004

By M. M. Hajdasinki

A project's rates of return (RORs)1, be it the internal rates return (IRRs) or one of the many IRR surrogates, frequently needs to be approximated. The success and efficiency an ROR- approximation procedure depend on the quality the approximation-initiating parameters, such as bounds or seed values (guesses). The existing approximation procedures commonly use bounds and guesses suggested by intuition rather than supported by mathematical considerations. This paper presents three mathematically founded ROR-bounding and eleven ROR-guessing approaches and examines their suitability by using examples of typical project cash-flowpatterns (CFPs). The calculated bounds and guesses not only improve the approximation efficiency, but also allow the process of the ROR discovery to be automated, thereby making it more convenient and reliable.

Jan 1, 1999

By Rene Steensma

The possibilities of the use of ultrasonics in the extraction of gold and silver is the subject of a study initiated in our laboratory since the beginning of 1986. The study consisted of various aspects of extraction, the results of which are in· different stages of advancement. Reduction in leach time combined with higher recovery are the most striking effects so far. The ultrasonics machine, originally part of a small pilot plant, forms now part of a much larger unit. This has the remarkable effect of even higher recoveries and shorter leach times. These data suggested a study on the possibilities of reduction of thiourea consumption. Although promising, the results of these studies require check testing and will be published as soon as our findings have been confirmed. During the study, which consisted of the application in thiourea and cyanide leaching, some interesting side effects were observed. In the first place, a reduction in penetration time which might make coarse grinding feasible. Secondly, an increase in compaction of the filter cake which reduces pregnant liquor losses, especially with clayey ores and industrial waste products. These will be studied under contract in the near future.

Jan 1, 1998

By W. Kemp Wait

Electronic ore sorting is a coarse particle beneliciating process which performs a function which in the past was primarily achieved through the use of hand picking belts. Photometric ore sorting is capable of separating waste from mineral bearing rock having a distinct difference in surface light reflectance levels. This type of ore sorter can be applied to gold and silver ores which are contained in quartz veining. Photometric ore sorting has been used at gold mines in South Africa as well as the Black Pinc silver mine in Montana. A new ore sorter has recently been developed with precious metal ores in mind. This ore sorter is capable of sorting ores on both photometric and conductivity sensing parameters. The first production machine has been installed at a gold mine near Beardmore, Ontario and currently is being used to process low grade waste dumps.

Jan 1, 1998

By D. Brabec

One of the analytical problems in exploration geochemistry is the choice of a method of sample attack which would be rapid, simple and reliable in terms of precision and discrimination between different concentration levels of elements sought. The wet sample attacks currently used in analysis of silicate rocks vary from total decomposition to leaching by weak extractants. The total decomposition of such materials is usually achieved either by alkaline fusion or hydrofluoric acid attack. The first method requires the use of platinum vessels which is both expensive and slow for batch operation. The second type of attack is more widely applied in rock geochemistry1, but it is still relatively slow for exploration purposes and requires extra care (especially when hydrofluoric acid is used in mixture with perchloric acid). Considerable improvement in speed can be achieved by using the sample attacks which release only part of the metal present in a rock.2,4 One of such attacks is the leaching of pulverized rocks by hot aqua regia.3 Another technique widely used in geochemical prospecting involves fusion of the samples with potassium pyrosulfate (or bisulfate) followed by an acid leach of the malt .5 One of the advantages of these techniques is the use of glassware in decomposition stage which considerably increases the analytical productivity. It should be noted that partial chemical attacks tend to extract from a rock mainly the non-silicate metal which may give results more significant for exploration purposes than the analysis for total metal.

Jan 1, 1970

By J. S. Meyer

Although salmonid fishes (including Pacific salmon and trout) have only intermediate sensitivity to copper (Cu) for traditional toxicity endpoints (survival, growth, and reproduction) and thus do not ?drive? the freshwater Cu criteria (e.g., see species-sensitivity ranking in US EPA 2007), Cu concentrations as low as 1 to 2 µg/L have been reported to impair olfaction (the sense of smell) in salmonids in laboratory experiments using dilute fresh water (see references in Meyer and Adams 2010 and DeForest et al. 2011). Olfaction is crucial to predator avoidance, recognition of kin, and reproductive synchronization (Baldwin et al. 2003); and Cu is of general ecotoxicological concern because it can be present in acid/mine rock drainage, industrial and municipal effluents, agricultural runoff, and urban stormwater runoff (Meyer et al. 2007). Therefore, there is public concern that the current regulation of Cu in surface waters is not stringent enough to protect salmonid fishes against olfactory impairment (e.g., OSU 2007; Pearson 2007). Because the toxicity of metals to aquatic organisms is a function of water chemistry [e.g., acute toxicity of Cu generally decreases as pH, water hardness (Ca2+ + Mg2+), alkalinity, and dissolved organic carbon (DOC) concentrations increase; Meyer et al. 2007], hardness-based freshwater criteria for metals are lower at lower water hardness. The recently-developed biotic ligand model (BLM) explicitly takes into account all four of those water chemistry parameters and the concentrations of other major inorganic cations (Na+, K+) and anions (Cl-, SO42-) to predict the acute toxicity of cationic metals (e.g., Ag, Cd, Cu, Ni, Pb, Zn) to aquatic organisms; and the BLM has been adopted by the U.S. Environmental Protection Agency (US EPA) to calculate acute and chronic national freshwater criteria for Cu (US EPA 2007). Consistent with observations of Cu toxicity to aquatic organisms, BLM-based Cu criteria generally are lower at lower pH, water hardness, alkalinity, and DOC concentrations. Therefore, although threshold concentrations for olfactory impairment by Cu can be low in dilute fresh waters, the corresponding hardness-based and BLM-based Cu criteria for the same waters also tend to be low. This leads to a logical question: Are Cu criteria already protective against impairment of olfaction in salmonid fishes, thus obviating the need to decrease those criteria even lower to protect against adverse effects to this physiological/ecotoxicological endpoint? Herein, we demonstrate that in all studies conducted to date, the US EPA?s BLM-based freshwater Cu criteria would have been protective against olfactory impairment in salmonid fishes, but the US EPA?s hardness-based criteria would not always have been protective. This distinction is important because all 50 States in the USA still use hardness-based Cu criteria in their water quality standards, and only some of the States allow use of the BLM to calculate site-specific Cu criteria. Additionally, in the absence of empirical results for calibration of a saltwater Cu-olfactory model, we demonstrate that a proposed unified freshwater-saltwater Cu-olfactory BLM predicts the US EPA?s current saltwater Cu criteria would be protective against olfactory impairment caused by Cu in sea water.

Feb 27, 2013

By D. W. Boening

Xanthate salts have demonstrated effectiveness as a flotation reagent in the recovery of heavy metals from mining wastewater. However, due to their strong ionic potentials, they are generally toxic to aquatic life. Under ambient environmental conditions, the half¬life of a xanthate is approximately four days. As a soluble salt, xanthates will complex with the metallic ions contained in water and fish. Some researchers have proposed that this complexing may extend the halflife, as well as optimizing the transfer of a given metal from solution across the gill surface. Leakage of xanthate treated wastewater into the surrounding surface waters is the most common route of exposure for aquatic plants, invertebrates and fish. Because this is an emerging mineral-recovery technology, more information is needed regarding xanthate toxicity and environmental fate before environmental impacts can be assessed with any degree of certainty.

Jan 1, 1999

By Yues Bertube

Molybdenite and chalcopyrite are two often-associated minerals. In Quebec, the Gaspe Copper Company, a subsidiary of the Noranda group, currently operates a molybdenite flotation circuit to recover a one percent trace of this mineral in the chalcopyrite concentrate. The low levels of molybdeni 2 preclude the use of flotation to remove molybdenum directly from the ore while scavenging of chalcopyrite concentrate for molybdenite yields a concentrate of the latter of somewhat inadequate quality. Such a situation could possibly best be solved by hydrometallurgical means, if molybdenite could be leached selectively from the chalcopyrite concentrate. Work in the field of extractive metallurgy was initiated about 22 years ago in the laboratory of the department of mining and metallurgy at Laval University, Quebec. Following a literature search, two objectives were selected. The present talk will outline some of the results obtained to-date and it is hoped the ensuing discussion of the paper can raise questions of immediate assistance to us for the future. First, as an immediate objective of-practical use, the oxidation rates for molybdenite and chalcopyrite in alkaline media would be studied under conditions of possible industrial application. Secondly, the kinetics of mass transfer of gases in pressure reactor are to be studied. Solubility data for various gases in aqueous solutions have been gathered by a few investigators, to mention the work of Pray1, Wadsworth2, Pawlek3 and Gerlach. Scattering in experimental results and discrepancies between authors are ominously present. Kinetics of mass transfer have somewhat been more neglected. A systematic investigation by the school of Berlin has greatly helped in the design of impeller most suitable for gas dispersion, without much reference however to the solid dispersing ability of the various designs. Variables affecting rates of gas transfer to the solution have not been studied. Studies on the aqueous oxidation of sulfide minerals are much more numerous. While molybdenite has been relatively less studied, work has been carried in two areas namely in alkaline oxidation of MoS2 , work performed by Dresher2 and Wadsworth, and in the hypochlorite leach of molybdenite by Bhappu4 and co-workers, These two methods showed appreciable rates of leaching for molybdenite. In general, comparisons between rates of oxidation of this sulfide with that for chalcopyrite have not been made.

Jan 1, 1972

By Bruce D. Hulman, Robert .. F. Gorman

Introduction Groundwater resource evaluation has historically required extensive field investigative work, usually at great cost. More recently, the advent of the microcomputer has made difficult aquifer and groundwater evaluations comparatively simple and less expensive. A groundwater model is a numeric solution to a set of equations that calculates the water level in an aquifer or other types of water bearing strata. A computer will execute the solution of the set of equations rapidly and thereby permit evaluation of large amounts of hydrogeologic data rapidly. Computer modeling of groundwater resources is very often used to forecast the effects of multiple uses of a single groundwater resource. Modeling of heavily used aquifers has proven to be beneficial for averting problems arising from competitive use of a groundwater resource. This paper describes the work tasks performed in order to evaluate a large alluvial aquifer and thereby predict the hydrologic impact of additional groundwater withdrawal. Purpose and Scope Neyer, Tiseo & Hindo, Ltd. (NTH) was retained to evaluate the groundwater supply potential of the Missouri River alluvium underlying the Fairfax District in Kansas City, Kansas (Figure 1). The proposed groundwater supply is being considered for industrial use as non-contact process water and a heat exchange medium for plant climate control. The anticipated peak groundwater demand is estimated to exceed 30 million gallons per day (MGD) during the summer months, with an average daily demand of nearly 25 MGD. The proposed groundwater supply was to be developed from 15 large-diameter production wells located at positions that would minimize potential interference.

Jan 1, 1987

By Henri Letient, Tom Aley, David Evans

Antamina is a large open-pit copper and zinc mine located within the Central Andes of Northern Peru at an altitude of 4300 masl. The facilities are situated within the headwaters of several watersheds, within the Amazon basin. Nearby villages rely heavily on springs and streams for drinking and irrigation water. The principle source of baseflow during the dry season is from Cretaceous karstic limestone aquifers. Antamina will produce nearly 1.4 billion tonnes of waste rock over its mine life. Finding suitable sites for storing large volumes of waste rock is often a challenging task – especially in karstic, alpine terrain. Detailed hydrogeological investigations are essential for delineating the karstic hydrogeologic watersheds associated with the proposed waste facilities, which are often very different than topographic (hydrologic) watersheds. Contamination vulnerability mapping at Antamina consisted of geological and karst mapping, geophysical surveys, geochemical testing, dye-tracer studies, drilling and aquifer testing. Detailed mapping followed by dye-tracer studies proved to be the most cost-effective methods for characterizing the karst aquifer systems. The results were used to optimize waste rock management at the site to minimize potential impacts on groundwater resources.

Jan 1, 2005

By C. Bailey Williams

Aragonite "sand," an oolitic lime-stone, is distributed throughout the Bahamas on the Grand Bahama Bank, adjacent to Southeast Florida. Bahamian deposits hold 75-100 billion tons of recoverable Aragonite. Aragonite's precipitation from seawater over 700 years ago assures low contaminates, making it a pure material for such industries as cement, glass, etc. A 90-acre, man-made production island was built south of Bimini, adjacent to ocean shipping channels mining is by cutterhead, suction dredge, dewatering, and stockpiling for further drainage and shipping. Aragonite is transferred to the U. S. East and Gulf Coasts via bulk carriers to points of sale.

Jan 1, 1978

By Ronald P. Wright

ARAMIDS UNDERGROUND COAL MINING

Jan 1, 1993

By Gregg R. Bierei

Arch of Illinois is a mining complex comprised of two surface and two underground mines located in Perry County, in southern Illinois. The company a division of Apogee Coal Co. of St. Louis, MO. Arch of Illinois' two surface mines, the Captain and Horse Creek Mines, use large stripping shovels and cross-pit bucketwheel excavators to remove overburden from three seams of coal, the Herrin No. 6, Harrisburg No. 5 and Danville No. 7. All are considered high sulfur reserves. The two underground operations are managed by Arch of Illinois. They are the Kathleen Mine and the newly constructed Conant Mine, which began production in 1991. Both underground mines are continuous miner operations. They mine the No. 6 coal, which is about 1.8 m to 2.1 m (6 to 7 ft) thick. All coal is currently transported by truck to a central preparation plant located at the Captain Mine. This preparation plant produces 27 kt/d (30,000 stpd) of clean coal. Production in 1992 reached 5.9 Mt (6.5 million st) of saleable coal. Of that, about 66% or 4 Mt (4.4 million st) are produced by the surface mines and the rest the by under ground operations. Change is in the wind for Arch of Illinois. In 1988, 100% of all production (6.2 Mt or 6.9 million st) came from surface operations. By 1995, only 38% of production is scheduled from surface mines. And by the year 2000, 100% of production will from underground mining methods. Dwindling low ratio reserves, compounded by increasing environmental and land acquisition costs, coupled with more efficient underground mining equipment, have started an evolutionary trend toward development of underground reserves. For Arch of Illinois to maintain profitability of remaining surface reserves and to compete effectively mining underground, it must improve efficiency, productivity and cost reductions. These efforts are essential for maximizing current surface reserves and to ensure a continued existence in the presence of clean air legislation and the softening of the high sulfur coal market.

Jan 1, 1993

By Drew Hobert, John Nielson, Erich Dohm

Metallurgical coal is an essential component for the blast furnace-basic oxygen furnace (BF-BOF) steelmaking process, which accounts for roughly 70% of total global steel production. To meet the growing demand for metallurgical coal, Arch Resources identified the potential to recover low- ash coal from ultra-fines discarded prior to the deslime flotation circuit across their portfolio of operations. Historically, many flotation circuits were designed to discard this ultra-fine coal due to high clay content and technological barriers to cost-effectively upgrade and dewater the coal to a saleable product. Recent advancements in high-intensity flotation technology, including the Eriez StackCell, have enabled coal producers to recover ultra-fine coal while minimizing capital and operating costs. In July 2023, Arch Resources commissioned the first full-scale ultra-fines recovery circuit utilizing StackCell high-intensity flotation technology at the Leer Mining Complex. This paper reviews the approach utilized to develop the flotation process design, learnings from the commissioning and ramp-up period, and performance data through the first year of operation.

Feb 1, 2025

By Andreas G. Mueller

Gold-silver and copper-gold deposits with high-temperature wallrock alteration of Ca-Mg-Fe-Al silicates occur in ca. 3.0 Ga old greenstone belts of the Yilgarn Block, Western Australia. The deposits are hosted by amphibolite-facies komatiites, basalts and BIF, controlled by ductile shear zones and located within the contact-metamorphic aureoles of composite granodiorite-granite batholiths. Disseminated sulfides and free gold form foliation-parallel ore zones in a gangue of anhydrous silicates (garnet, clinopyroxene, olivine), hydrous silicates (amphibole, biotite) and calcite. The deposits may be classified on the basis of their dominant economic metals as: 1(1) Gold skarns with substantial silver as by-product, represented by the Marvel Loch mine (production: 2,200,000 t at 3.5 g/t Au), and characterized by the mineral association pyrrhotite, loellingite, arsenopyrite, galena, gold and magnetite. (2) Gold skarns with low silver contents, represented by the Nevoria mine (production:1,850,000 t at 3.4 g/t Au), and characterized by the mineral association pyrrhotite, chalcopyrite, arsenopyrite, gold, Bi-tellurides and magnetite. (3) Copper-gold skarns, represented by the Elverdton mine (production: 850,000 t at .7 5 Cu, 0.81 g/t Au), and characterized by the mineral association magnetite, chalcopyrite, pyrrhotite, pyrite, gold and Ag-Bi tellurides.

Jan 1, 1990