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By D. K. Marjaniemi

The U.S. Bureau of Mines inventoried and characterized mineral sites and production plants within 200 km of the border in both the U.S. and Mexico. Sources of information included the USBM Minerals Availability System, the USBM Automated Mineral Information System, the USGS Mineral Resources Data System, the Mine Safety and Health Administration Address/Employment File, and the literature. Three hundred seventy-eight major construction material and industrial mineral properties were identified and characterized in the U.S. and Mexican parts of the Borderlands. Sixty-six major metallic mineral properties were identified and characterized in the Mexican part of the Borderlands.

Jan 1, 1996

By L. Blain

In practice, geochemical analyses can be grouped in two broad categories according to their aim. Those that seek to determine the exact chemical composition of geological materials fall under the heading of assays, whereas applied geochemistry concerns itself with the detection of anomaly contrasts. Recent trends have blurred the distinction between both approaches for many users, as methods that were traditionally used for assays are being adopted in applied geochemistry and assays make increasing use of instrumental techniques. Nevertheless. it is important to keep a clear distinction between the two types of analyses because it has immediate practical consequences, cost is the most obvious, as well as fundamental implications. In the broadest terms, the goal of geochemistry is to strike an optimal balance between throughput and accuracy, at the lowest reasonable cost, while assays strive for accuracy. Traditionally, complete silicate analysis has been the concern of assayers whereas exploration geochemists have been more interested in base metal analyses where acid extractions of the elements, without dissolution of the silicate matrix, has been the norm. This kind of distinction is less realistic now, especially with the growth in lithogeochemical studies, and some overlap in methodology is unavoidable. However, where such overlaps occur the distinction remains in the emphasis of the work. A commonly used example is that although HF acid preparations are used by both, the emphasis in applied geochemistry is on sample throughput and batch analysis, whereas assayers are more concerned with the range of elements to be determined (Thompson and Walsh, 1983).

Jan 1, 1993

Simulation has established itself as an accepted tool for the design and optimization of complex minerals processing plants. This paper addresses the use of simulation as a tool for the design and optimization of carbon-in-pulp and carbon-in-leach (CIP/CIL) plants. The complex, interactive nature of CIP/CIL plants makes detailed experimentation an expensive and time consuming approach to CIP/CIL plant design and/or optimization. This paper discusses a simulation-based software tool that can make the process of CIP/CIL plant design and/or optimization much more cost effective. Many of the issues and problems pertaining to the use of simulation for CIP/CIL design and operation are generic. Thus, this paper also attempts to highlight generic issues that must be solved before simulation will become a more widely used design and optimization tool. Requirements for the application of simulation for CIP/CIL plant design and optimization are highlighted. Similar problems and issues can be identified for most mineral processing plants.

Jan 1, 1994

By P. S. Hettinger

Land Application Discharge (LAD) is a useful method of disposing of waste water from mining operations and in certain climatic regimes, stormwater runoff. LAD systems function under the premise that metals, salts and nutrients in water are dispersed over a large area and are effectively assimilated into the soil profile. Depending on the soil structure, migration or mobilization of dissolved metals through the soil profile can be Substantially reduced. Land application of treated effluent from sewage lagoons or waste water plants was probably the first general use of land applied water. LAD has gained popularity with the mining industry as a means of disposing of waste water and process water. In addition, large volumes of snow meltwater and stormwater are often placed in storage in Montana during spring, and Land Application Discharge has shown to be an effective method for disposing of stormwater during the dry, summer season. LAD can also provide an alternative to recycling or treating waste water at on-site waste water treatment plant&. Application of stormwater or process water can result in little or no change to the background concentrations of metals in baseline water quality samples. One cautionary note about LAD: high salt concentrations and pH values are associated with process water from heap-leach facilities and are known to cause burning of local vegetation. Some pre-treatment of process water may be necessary to prevent such environmental problems.

Jan 1, 1994

By Ahmed I. A. Salama

The problem of estimating separation characteristics by utilizing mass distributions of feed and products is considered. The separation characteristics include mass yield and partition curve. The cases of mass balance and partition functions balance are identified. The developed techniques can handle the cases of two- and three-product separation. Actual data are utilized to demonstrate the proposed techniques.

Jan 1, 1992

By I. R. McGowan, J. Tilk, J. I. Hershman, R. L. Lewis

The White Pine Mine is a large underground copper mine located in the Upper Peninsula of Michigan. A numerical ground water flow model of the White Pine Mine was constructed to evaluate potential engineering controls that would reduce the rate of mine-water discharge after closure. Of the passive controls evaluated, the placement of bulkheads within the mine workings was predicted to offer the greatest benefit, reducing the rate of discharge by as much as 35%.

Jan 1, 1998

By Deepak Malhotra

The economic viability of mineral companies not only depends on maximizing mineral recoveries but also on their ability to do so at minimum cost. Increasing pressure to cut costs has resulted In reduced staff, thereby decreasing the capabilities of routine metallurgical audits. This paper reviews a systematic approach to plant auditing which has been used successfully at several operations. Several case studies illustrating the potential benefits that can be attained from flowsheet auditing of mineral processing plants are discussed.

Jan 1, 1991

By Mark R. Stanton

Geochemical and mineralogical analyses of 46 samples from six drill cores in the Mayday mine pile near Silverton, Colorado, demonstrate wide variability in trace metal contents with spatial location. This variability results from the original geochemical composition of mined rocks, mixing of ore and non- ore rocks during emplacement of the pile, and weathering since rocks were placed in the pile. Weathering reactions are controlled by factors such as pile thickness (depth), water availability, microbial activity, and mineral dissolution and formation kinetics. These factors result in variable redistributions of trace metals from primary (ore) to secondary (weathering products) minerals within each core.

Jan 1, 2000

By W. D. Hall, M. Norris, J. R. Henke

Dewatering wells producing iron-rich water experience rapid declines in yield and drawdown due to the formation of ferric (Fe3+) hydroxide deposits in well screens, pump intakes and riser pipes. Precipitation is caused by a combination of dewatering-promoted iron oxidation and iron oxidizing bacteria. Physical and chemical well rehabilitation techniques, as well as alternative well-construction and well development techniques, were evaluated in this study. The addition of acid downhole feed systems to dewatering wells that are prone to iron encrustation can, in many cases, prolong their operational lives up to 500% that of unacidified wells.

Jan 1, 1992

By George D. Tikkanen

The world supply of zinc and lead is reviewed. The nature of zinc and lead deposits, production constraints, current production and reserves, new developments, possible future developments, and closures are considered. Lead sup- plies for the future are adequate. Zinc supplies are expected to tighten in the longer term due to growth in zinc consumption and orebody depletion.

Jan 1, 1986

By S. R. S. Sastri

By using the data of E.A. Hersam and F.C. Bond's equation for energy consumption in comminution, a method was developed to analyze the performance of industrial jaw crushers. The study showed that industrial jaw crushers are generally operated below capacity. The study also showed that industrial jaw crushers generally have sufficient installed power to operate at, full capacity. The method presented can be used to estimate the capacities and power requirements of jaw crushers.

Jan 1, 1995

By S. D. Thompson, L. Adler

This study reviews and analyzes the empirical methods available for designing the capacities of coal mine gathering belts. The analyses lead to recommendations concerning the application and implementation of each empirical method. Operations research techniques, mainly simulation models, are also briefly mentioned, and a few recommendations are made concerning their selection and application. The objective of the study is to provide a reliable basis for the practicing engineer to properly select, apply, and implement a capacity design method.

Jan 1, 1988

By Mark W. Springett

The examination of relatively well behaved distributions subject to truncation by a cutoff grade in the mine clearly demonstrates that a bias is inevitably introduced when the selection is based on the results of samples which are subject to even the most idealised error distribution. The idealised error used in this paper is assumed to be normally distributed with a mean of zero and is thus unbiased. The bias introduced can be minimised but it cannot be eradicated. A better understanding of the bias can lead to improved procedures for mine sampling, sample preparation, assaying and estimation of selection units which will not only reduce the discrepancy but more significantly will increase the efficiency of mining selection and hence profitability.

Jan 1, 1989

By Dorothy A. Canter

Three Federal programs exist for identifying significant environmental chemicals, including minerals, that should be tested for toxicological effects. Two programs are mandated by law and can lead to industry-funded studies; they are administered by the Environmental Protection Agency and the Agency for Toxic Substances and Disease Registry, respectively. The third is the National Toxicology Program, a Federally-funded testing initiative. This paper summarizes the three programs, describes their similarities and differences, and discusses their applicability to minerals.

Jan 1, 1991

By Michael L. Nave

Mining belt conveyor elements are becoming larger and more expensive. Conveyor reliability requirements are rising. Conveyor condition monitoring can aid maintenance, reliability, and risk management in conveyor system operation. This paper examines the application of condition monitoring in coal mining belt conveyor systems. Types and form factors of condition sensors are described. Example costs are included. Suggestions for OEM developments are examined. Application problems are discussed. Two simple cost case studies are presented.

Jan 1, 2000

By R. R. Rollins

Field data combined with theoretical derivations were used to design a surface mining operation using explosive casting. Calculated casting results varied from 44% to 65% depending on bench height. The field tests were performed at an Eastern, contour, coal stripping operation. Results from five experimental casting shots, using a shovel and trucks, are summarized and compared to conventional mining methods. The overburden material removed by casting ranged from 35% to 65%, with an average of 50%. Fragmentation was improved, and it was demonstrated that this procedure is economically attractive, with a resultant cost savings of $0.59/m3 or $5.93/t of clean coal.

Jan 1, 1988

By Kal V. S. Sastry, Stephen N. Little

Computer simulation of comminution systems is found to provide significant cost savings by enabling efficient circuit design and development of control systems. These simulation systems are based on sound mathematical models and numerical methods. Nevertheless, they are found to be hard-to-use and hard-to-modify to carry out more elaborate process analysis. This paper discusses the fundamental principles and practical aspects of an advanced, highly functional, and user-friendly SIMulator for COMminution, SIMCOM, that is being developed at Berkeley by incorporating state-of-the-art software engineering principles.

Jan 1, 1992

By John A. Herbst

Mineral processors have evolved from "handbook-based" decision makers to "model-based" decision makers. With this evolution have come significant improvements through increasing productivity, decreasing capital and operating costs and increasing product quality. This paper traces the development of model-based decision-making technology over the last 40 years and documents the benefits resulting from systems optimization using these tools. Some speculation is ventured concerning the future of model-based decision-making tools and their use in the field of mineral processing.

Jan 1, 2000

By W. K. Tolley, D. G. Kotlyar

Oxidized sulfide minerals, commonly formed by weathering, are becoming increasingly important resources as primary sulfide deposits are depleted. Oxidation, in general, reduces selectivity and recovery in flotation. The objective of this research was to determine the mechanisms of oxidation and collector adsorption in sulfide systems as a step towards developing improved technologies for beneficiation of oxidized sulfides. Data from microcell flotation tests are combined with electrochemical and spectrophotometric measurements. The adsorption of ethyl xanthate (EX) on oxidized sulfides was characterized using AC impedance and voltammetry techniques, and correlated to flotation response. Oxidation resulted in an electrically resistive, nonporous surface layer. The floatability of chalcocite, chalcopyrite and pyrite was dependent on the extent of oxidation. Oxidation for one day or more at 65ºC suppressed chalcocite flotation. Oxidized chalcocite also inhibited flotation of chalcopyrite and pyrite. Oxidation caused decreased chalcopyrite flotation. Pyrite flotation, however, increased after oxidation.

Jan 1, 1995

By Bernard J. Reddy

This paper describes in detail the economic forces affecting cobalt supply, demand, and prices. The major factors that will determine the growth or decline in the use of cobalt in each of its applications are discussed. The flows of cobalt from mine to refinery are described on a company-by-company basis. The paper concludes with a discussion of how the characteristics of the supply and demand sides of market interact to determine cobalt prices.

Jan 1, 1986