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By J. B. Hiskey, V. P. Atluri

Resin-in-leach (RIL) cyanidation experiments were performed on a refractory carbonaceous gold ore. The objective of this investigation was to determine if strong-base ion exchange resins could adsorb the soluble aurocyanide complex in preference to natural "preg robbing" organic constituents. Direct cyanidation of the carbonaceous gold ore used in this study resulted in less than 2% gold extraction in 24 hr. RIL cyanidation resulted in about 70% gold recovery onto the resin. Kinetic experiments indicated that 50% of the gold is extracted after 1 hr of leaching. Resin breakage was investigated for as-received and preattrited resins. Similar results were obtained with three different strong base resins.

Jan 1, 1990

By I. de Jong, G. Van Weert

Silver cyanide adsorbs extremely well on activated carbons. This suggests that the addition of soluble silver salts to trace cyanide containing waste streams should allow efficient cyanide removal with active carbon. Silver losses, however, would make this method expensive and also objectionable, since silver has biocidal effects. When silver impregnated carbon is used, these problems are overcome. Test work has shown that such silver remains on or in the active carbon, that cyanide concentrations can be reduced to the level of detection (< 5 ppb) and that the silver impregnated carbon can be reactivated with equipment similar to that now in use at gold milling operations. Initial results on the type of carbon, the impregnation procedure and the level of silver, and the effect of repeated regeneration are discussed.

Jan 1, 1992

By James G. Sampson

The discarded phosphatic clays from mining operations have historically been stored behind earthen dams for long periods of time before any reclamation was accomplished. In efforts to expedite the dewatering and reclamation of the clay ponds, the phosphate industry explored alternatives to conventional clay disposal practices. One alternative, employed by CF Industries, Inc., combines the clay and the discarded sand prior to disposal behind earthen dams. The sand encourages the clays to &apos;give up&apos; trapped water more readily resulting in enhanced consolidation behavior. This paper provides an overview of the sand-clay mix process including the reclamation of sand-clay disposal areas.

Jan 1, 1992

By J. S. Y. Wang, R. C. Trautz

To evaluate the potential for water seeping into an underground opening, a 9-m- (30-ft-) long drift was constructed in the unsaturated fractured tuff at Yucca Mountain. Forty seepage tests were performed by releasing finite volumes of water at a constant rate into short test intervals located in boreholes positioned above the drift. The seepage threshold flux, defined as the liquid-release flux at and below which water will not drip into the opening, was determined for 10 test intervals. The seepage data, observations and model results indicate that a seepage threshold exists because a capillary barrier diverts water around the opening.

Jan 1, 2002

By A. Knoll, J. W. Beck, W. C. Brice, E. K. Lehmann

A cooperative study was undertaken in a neutral atmosphere by representatives of the environmental community, the mining industry and state government to identify and resolve environmental issues associated with base and precious metal mining before a commercial mining development is announced. The study included testing Minnesota&apos;s as-yet-untried nonferrous mining regulatory program using three hypothetical mining developments sited in environmentally sensitive areas where future mining could occur. Results include identification of critical paths for regulatory decision making, identification of particularly sensitive environmental issues that mill need continued deliberation before resolution and characterization of data necessary for environmental review and permitting decisions.

Jan 1, 1992

By S. B. Bhagwat

Equipment capacities of a sample of Illinois surface coal mines representing about 60% of surface production in the state were studied. Available equipment capacity was compared with the required capacity, as indicated by coal production and stripping ratios reported. Most mines sampled showed surplus equipment capacity, which if avoided, would result in substantial cost savings. The surplus capacity results mostly from market fluctuations that result in underutilization of equipment. Study findings underline the importance of market assessment at the time of mine planning and of communication between marketing and engineering arms of a coal firm.

Jan 1, 1987

By K. N. Han

The dissolution kinetics of cobalt in iodine/ iodide solutions were investigated using a rotating-disc technique. Variables studied included temperature, rotating speed, concentration of lixiviants and the pH of the solution. The overall dissolution reaction appeared to be limited by the mass transfer of tri-iodide through the diffusion boundary layer with an Arrhenius activation energy of <16.2 kJ/mol (4 kcal/mol) over the temperature range of 2 to 42ºC. The pH of the solution had little effect, as long as the pH of the solution was <8. However, when the pH of the solution became >8, the dissolution rate decreased dramatically, due to passivation. The rate of dissolution was in good agreement with the dissolution model developed by the authors earlier.

Jan 1, 1995

By Silvia H. M. Grimaldi, Afonso H. Martins

The scope of this experimental work was to study the yttrium extraction and stripping behaviour in a solvent extraction system with mono(2-ethylhexyl)2-ethylhexylphosphonic acid (IONQUEST 801) in a chloride system The study was performed for only one contact between organic and aqueous phases The experiments were carried out according to a factorial design. Due to the statistical analysis and its experimental proof, the optimum conditions for maximum yttrium loading into the organic phase of the extraction stage were 16 minutes for time of contact between phases, 980 rpm of stirring intensity and pH=2.3 for the aqueous phase of the sovent extraction system. The optimized experimental conditions by the statistical approach for the stripping stage were: time of contact between phases equal to 20 minutes, 1050 rpm of stirring intensity and 1.75 M HCI into the stripping aqueous solution.

Jan 1, 1995

By K. N. Han

The adsorption of gold onto activated carbon in iodide solutions was studied. The adsorption rates were determined as a function of temperature, salt concentration and pH, as well as activated carbon concentration. A kinetic model was developed for the adsorption. The adsorption rate was believed to be controlled by a combined mechanism of film diffusion and pore diffusion with the film diffusion having the most significant effect. Experimental findings were in good agreement with the model developed. The apparent activation energy was found to be 14.9 kJ/mol.

Jan 1, 1995

By Regina N. Tempel, Laurie S. Balistrieri, Lisa L. Stillings, Maggy F. Lengke

The Dexter pit lake, within the Tuscarora volcanic field in Elko County, Nevada, formed after closure of the Dexter mine. Mineralogy at the Dexter mine is related to widespread feldspar, silica, and chlorite alteration. Major mineralogy includes quartz, alkali feldspar, albite, phlogopite-biotite, hornblende, iron-titanium oxide, chlorite, kaolinite, smectite, illite, and sericite, with lesser amounts of calcite, zircon, apatite, and rutile. Trace element geochemistry is characterized by high levels of As, Ba. Cr, Cu, V, Zn, B, Zr, Li, and U. Detailed mineralogy and geochemistry are required for geochemical models to accurately predict trace element concentrations in pit lake waters.

Jan 1, 2000

By B. Yarar, R. Buchan

Mineral-processing techniques were adopted for use in the separation of various plastics used in beverage bottles. A complete flowsheet, which utilized size reduction, heavy-media separation and flotation, was developed to separate PE, PVC and PET. In addition, the mixtures contained cellulose fibers (from labels) and aluminum (from bottle caps). It was demonstrated that, while heavy-media separation allows for the separation of a PVC/ PET mixture, froth flotation can be used to separate PVC and PET. For this purpose, the differential action of a pH 11 alkaline aqueous solution containing methanol and MIBC as surface-tension control agents, has been found to be a suitable flotation medium. This paper reports on some aspects of a flotation flowsheet that was developed for the separation of plastics contained in municipal solid wastes.

Jan 1, 1997

By Allan E. Koski

Michigan is the second largest iron ore producing state in the United States. The Empire Mine, celebrating its 30th anniversary in 1994, is the largest iron ore mine in the state. The Empire Iron Mining Partnership is an iron ore mining, concentrating and pelletizing facility managed by The Cleveland-Cliffs Iron Co., a subsidiary of Cleveland-Cliffs Inc. The Empire Mine is located near Palmer, MI on the Marquette Iron Range in Michigan&apos;s Upper Peninsula. The partnership includes Inland Steel Co., LTV Steel Co., Wheeling-Pittsburgh Steel Corp. and Cleveland-Cliffs. Mine construction began in 1960. The first pellets were produced in late 1963. Successive expansions in 1967, 1974 and 1979 resulted in Empire reaching a present annual capacity of 8.1 Mt (8 million long tons) of pellets. In late 1993, a milestone was reached with the production of Empire&apos;s 152-Mt (150-millionth long ton) of iron ore pellets.

Jan 1, 1994

In order to analyze and quantify distinct environmental properties in the vicinity of sites, the Site-Specific Natural Resources Information System (SARIS) has been developed based on a Geographic Information System (GIS). SARIS is one of the fundamental databases of a collaborative research program aiming at the resource orientated analysis of metallic raw material flows with aluminum and copper serving as exemplary case studies. The spatial database incorporates all present production sites of ore extraction, refining and smelting. Environmental data for each location were derived from global digital survey data covering land cover, soils, morphology, climate, topography and population density. The main application of this database is the characterization of environmental safeguard objects, which may be affected by the activity of concern. This site-specific environmental impact assessment is used to determine the relevance of environmental issues based on the distribution pattern of sites in a global framework. The derived results are used to suggest a tailored indicator approach to measure progress and performance of industrial developments relative to the predetermined site-specific conditions.

Jan 1, 2003

By R. A. Metz, Ted H. Eyde, Dan T. Eyde

Industrial minerals deposits present sampling and grade control problems not normally encountered in metal mining operations. No longer are industrial minerals simply crude ground mineral products but are in fact high purity chemical raw materials. Operators of industrial minerals mines and processing plants now must meet increasingly stringent specifications established by the consumer of the final products. Meeting these stringent specifications requires not only sophisticated processing techniques but equally important careful sampling and grade or quality control at the mine. A well-trained geological staff can assure an adequate supply of uniformily high quality feed to the processing plant. In the final analysis this results in significantly higher operating profits.

Jan 1, 1992

By Jun Li, Marc Le Vier, Rong Yu Wan, Jan D. Miller

The hydrometallurgical treatment of gold and silver ores by ammoniacal thiosulfate solutions in the presence of a copper catalyst has been actively studied in recent years. Such a process strategy is very attractive due to the low toxicity of the lixiviant and the efficient recovery of the precious metals from difficult-to-treat ores. Important features of the ammoniacal thiosulfate system for the recovery of precious metals from various sources are reviewed in this paper, including leaching, metal recovery, and system stability.

Jan 1, 1995

By Donald L. Meredith, Jeffrey Harris, Donald A. Stanley

Principal Components Analysis (PCA) is a versatile, multivariate statistical method that the Bureau of Mines is applying to mineral processing data to achieve data simplification and pattern recognition. The principal components are obtained from an eigenanalysis of the data matrix. To achieve data simplification PCA replaces a larger number of measured variables with a smaller set of principal components and at the same time removes a significant amount of experimental error. Data simplification and error reduction make PCA useful in process control. Plots of the individual principal components form the basis of a pattern recognition technique that allows detection of significant variations in the structure of the data. These applications of PCA are illustrated with appropriate mineral processing data.

Jan 1, 1993

By David J. Gurtler

In early 1988, Chino Mines Co. began using a system of economic splits for all materials encountered in mining. All mined material is evaluated as mill ore, solvent extraction electrowinning plant feed, and non-ore material, to determine its disposition. Results thus far indicate a significant increase in financial returns on material mined compared with the copper cutoff grade previously in use. Chino Mines is a partnership between Phelps Dodge Corp. (two-thirds ownership) and Mitsubishi Corp. (one-third ownership). The company produces copper and byproduct metals from the historic Santa Rita del Cobre mining district in southwestern New Mexico. The history of copper production in the district began with the use of surface native copper by native Americans before 1800. Spanish soldiers from Mexico later became aware of this district and mining began in 1801. The district was worked intermittently until 1909 when the Chino Copper Co. was formed, with Daniel C. Jackling as vice president and managing director. Concentrator operations were started in 1911. Kennecott purchased the company in 1933 and built a smelter in 1939. Chino Mines Co. was formed in 1980 when Mitsubishi purchased one-third of Kennecott&apos;s holding at the property.

Jan 1, 1990

By Gordon C. Gutrath

Queenstake Resources Ltd. has been exploring and mining alluvial gold deposits in the Yukon Territory and British Columbia since 1980. The five mines in production produced, in 1987, a total of 13,222 ounces. This paper will briefly review Queenstake&apos;s exploration program, property descriptions and mining methods, environmental concerns and a comparison of costs. (Sueenstake has been successful in developing a cash flow base from these operations that provide the capital for the acquisition and exploration of new, and hopefully, larger scale gold producers. NOTE: The historic alluvial mining unit of ounces per cubic yard and English units of measurement have been used throughout this paper. Dollars are Canadian unless otherwise noted.

Jan 1, 1988

By Djamhur Sule, Husaini

Almost 90 % of phosphate in Indonesia is consumed for natural and manufactured fertilizers, while the rest is used in chemical industries. The consumption of phosphate always increases each year, while Indonesian phosphate production is almost constant at around 75,000 tons annually, except the production in 1988 was 165,000 tons. Due to the limited amount of domestic production, the imported phosphate is increasing each year. Phosphate trading in Indonesia is unique. Some of the domestic production is exported to Taiwan, while phosphate from USA, Morocco, Jordan and Nauru is imported. Indonesian phosphate includes guano phosphate, caving phosphate and small amount of marine phosphate sediment. Problems with Indonesian phosphate include: scattered deposits in difficult locations and a relatively small amount of reserves. Exploitation of phosphate deposits for domestic purpose has a good prospect, mainly because of the rapidly increasing phosphate demand as natural fertilizer or as a raw material for manufacturing fertilizer to support an agricultural sector.

Jan 1, 1993

By M. Ericsson

The extractive industries consist of five major sectors: - Mining equipment and services - Dimensional stone - Industrial minerals - Aggregates - Metal mining These industries produce some finished goods but mostly semi-finished products as they feed into other industrial sectors: Basic metals, fabricated metals, construction, chemicals, dyes and pigments, inorganic chemicals, fertilizers, rubber and plastics and non-metallic mineral products. These are the major down-stream industries in this study. Taken together with the extractive industries they form the mineral resource based cluster. The mineral resource based cluster is a substantial part of the Finnish economy: It employs 211 000 persons, 39% of the number of employees in industry. The cluster?s exports account for 20% of industry exports. Value added is 34% of total value added in industry. Investments reach 35% of total industry investments.

Jan 1, 2003