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By T. V. Durkin

Approximately 1,390 t (44.7 million ounces) of gold have been produced in South Dakota since 1875. South Dakota's mining laws attempt to strike a balance between economic development and environmental protection by promoting mining as an industry while requiring prevention of pollution and reclamation of affected lands to a beneficial use. The mining laws have evolved since their inception in 1971, especially in response to gold mining. The laws have remained flexible to meet changing regulatory needs. Gold production has continued relatively unabated, even in the face of public scrutiny, two mining moratoriums, and isolated environmental problems. The department's system of "one-stop-shopping" for environmental permits streamlines the permit process, fosters quick resolutions to compliance problems, and helps keep enforcement actions out of the courts. Specific case histories at heap leach mines within the Black Hills are presented.

Jan 1, 1998

By Lennart Mukka

LKAB has been mining iron ore in northern Sweden for about 100 years and now enters the next century with a major new investment in Kiruna. The under- ground projects involve construction of a new main haulage level, a new mining system and a new ventilation system. This paper describes the Ventilation Procject from the investigation stage through to construction.

Jan 1, 1995

By H. Reginald Hardy, Maochen Ge

Data analysis is one of the most important steps required for the successful application of the acoustic emission/ microseismic (AE/MS) technique. A dedicated computer software package to analyze acoustic emission/ microseismic data associated with field applications in the geotechnical area has been developed recently at Penn State University. This paper addresses the major features and applications of this computer software package.

Jan 1, 1986

By Robert Moore Lewis

A unit for separating minerals Into two prescribed size fractions, designated as a Lewis Hydrosizer, was developed at the North Carolina State University Minerals Research Laboratory Ore samples with different mineral compositions, including coal, were separated effectively with the laboratory continuous unit Commercial size units are in operation in North Carolina and Mexico, and under construction In Norway Additional units are being built or are in the planning stage at several companies.

Jan 1, 1983

By Alan M. Ritchie, Paul Miskelly

The 2-D code FIDHELM has been used to simulate conditions in piles of pyritic material with vertical dimensions of 20 to 70 m and a horizontal dimension of 500m. Those properties of the pile and its external environment (wind, temperature) important in determining the time and space dependence of sulfide oxidation, have been identified. A prescription to evaluate the overall sulfide oxidation rate in a pile of known volume but variable geometry has been developed.

Jan 1, 2000

By Haydn H. Murray

Common clay includes a wide variety of clay and other fine- grained rocks that are used in many ways. These clays are some- times classified as miscellaneous clay and shale. Most products made from them are fired and include such things as structural and face brick, drain tile, vitrified pipe, quarry tile, flue tile, conduit, pottery, stoneware, and roofing tile. Very large tonnages of these materials are bloated by firing to form lightweight aggregate, and large quantities are used in making portland cement (see the specific chapters in this volume). Uses not requiring firing of a finished product include filler for paint and other products and shale and clay used for packing dynamite in blastholes and for plugging oil and gas wells that are no longer in use.

Jan 1, 1994

By W. R. Dearman, N. Turk

The theoretical relations between the strain and stress Mohr circles make it possible to establish a relation between the internal friction angle [ ] and the Poisson's ratio (v) of rocks. The internal friction angle is related to the Poisson's ratio as Sin [-] = (1 - v)/(l + v). This relation gives lower friction angle values than the triaxial Mohr envelopes and higher values than those given by surface sliding friction tests.

Jan 1, 1986

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 A. F. Symonds

The effects of harmonic resonance between the supply impedance and power factor correction capacitors on systems with large harmonic sources, such as mine winders, are well known. The similar effects of resonance with cable capacitance are not commonly encountered and, hence, are not always considered in the design of medium-voltage networks. This article considers some of the aspects of resonance between the supply impedance and the cable capacitance and presents one successful approach to solving the problem.

Jan 1, 1998

By R. M. Campoy

In this review of the copper, lead, zinc, and molybdenum industries in Mexico, the author describes how the country's position in the world base metals market and the climate for foreign investment in Mexico have been affected by the nationalization of the banking industry in that country and by recent mining legislation and the current national debt crisis.

Jan 1, 1988

By G. D. Hood, B. E. Davis

A fundamental study of the mechanisms involved in the conditioning of coarse Florida phosphate has led to some interesting discoveries. Studies by the US Bureau of Mines have shown that conditioning time and mixing intensity greatly affect the grades and recoveries of the phosphate minerals and quartz in the rougher concentrate. In particular, as the conditioning time or mixing intensity increased, the phosphate recovery remained constant while the amount of quartz floated decreased. This phenomenon is contrary to conventional wisdom and could lead to a more efficient coarse flotation circuit.

Jan 1, 1995

By Thomas W. Camm

The U.S. Bureau of Mines has extensive experience estimating the cost of mining and mineral processing operations as an ongoing part of its information and analysis studies. With the increased interest in remediation of mine wastes, the USBM is developing a methodology to expand its cost estimating expertise to include costs of various remediation techniques applicable to mineral processing and mining wastes. By integrating waste remediation costs with existing USBM cost estimating systems for mine and mill operations, a comprehensive system for cost engineering studies will be developed.

Jan 1, 1995

By Bruce A. Brown

Construction aggregate is the most important nonmetallic-mineral commodity in quantity and value that is produced in Wisconsin. Crushed stone is produced from the Precambrian crystalline rocks and the Ordovician and Silurian carbonates, and sand and gravel is extracted from Quaternary glacial deposits. Dimension stone is quarried from both the Precambrian crystalline rocks and Paleozoic carbonate rocks. Other nonmetallic minerals include industrial sand, lime, roofing granules, terrazzo aggregate, and peat.

Jan 1, 1999

By Daniel P. Coughlin, Robert C. Thomas, Christopher S. Romanek, Kristian W. Paul

Two separate constructed treatment wetland (CTW) systems receiving the same metal contaminated, acid sulfate water over different lengths of time and at different rates were evaluated for metal attenuation. Both wetlands are the alkalinity generator portion of a succesive alkalinity producing system (SAPS). Sequential extractions are employed to determine phases of metal removal. Results indicate that Fe, Al, Zn, Ni. and Cu accumulate in the organic substrate over time. Manganese accumulates initially, but is not retained in the system over time.

Jan 1, 2000

By C. M. Lundell, F. S. Kendorski, R. D. Prager

The criteria for the design of the shaft/tunnel system excavation at the Rocky Mountain Project was to provide a stable opening during and after construction to receive the concrete lining and to minimize the disturbance of the surrounding rock mass so that the rock mass resists the displacement of the tunnel mining upon internal pressurization. This paper will summarize the geotechnical design of the shaft, elbow, tunnel, bifurcations, and penstocks

Jan 1, 1986

By J. J. Schwoebel

Resource Enterprises Inc. (REI) is exploiting the coalbed gas resource by working in unison with active underground mining operations. At REZ7s pilot project at the Soldier Canyon mine, Carbon County, UT, RE1 has drilled nearly 15.25 km (50,000 ft) of horizontal in-seam and slant boreholes during the initial two years of drilling activity. Produced gas has been sold to a natural gas transmission company on a continuous basis since mid 1983.

Jan 1, 1988

By P. Venkatsubramanian, D. R. Maneval

An insufficient hydrologic data base exists for most large and small coal basins in Alaska owing to the lack of need in the past to collect data. The runoff process is insufficiently understood which is complicated by specifically northern phenomenon, and the lack of understanding of hydrologic relationships in permafrost environment. This paper presents an understanding of the hydrologic effects of frozen ground and presents methods by which the influence of surface mining upon the hydrologic balance can be analyzed.

Jan 1, 1987

By Sandra L. Maxfield, Alan Mair

Strategic design of groundwater monitoring programs can increase public confidence in mine management, decrease financial assurance requirements, and minimize environmental budgets. Monitoring of inorganics is challenging because many occur naturally with baseline concentrations fluctuating spatially or temporally. Evaluating monitoring data to distinguish between a hazardous release or a natural fluctuation in baseline concentration can be controversial. In order to develop an effective program, monitoring parameters should be selected which are mobile and stable. Statistical procedures should be customized to address the uniqueness of groundwater systems. Calculated baseline concentrations should minimize the false negative & false positive rate.

Jan 1, 1995

By Veliko Kertikov

Complicated processes of heat exchange and evaporation, leading to changes in the temperature and humidity of the ventilating air flow, take place during the driving of headings. In the case when virgin rock temperature is high, the increase in air temperature and humidity is significant. This causes a deterioration of climatic conditions in the headings. Procedures for predicting the changes in air temperature and humidity are discussed, together with appropriate calculations and computer programmes. Predicted results for example scenarios are used as a background for the selection of approaches and means to improve the climatic conditions in a dead-end heading using auxiliary ventilation.

Jan 1, 1997

By Dean J. Soderstrom

Soil and sands were contaminated with depleted uranium from weapons testing. This resulted in the formation of a complex mixture of uranium compounds. Characterization studies of the soil indicated the uranium was present as uranium metal, uranium oxides, silicon-bearing metallic uranium, and uranium silicates. A process was developed to selectively remove dense uranium compounds using gravity separation and a chemical extraction system to remove uranium which was not available for separation by gravity methods. Results from characterization studies and pilot scale testing are presented for background information. The primary purpose of this presentation is the report of the results achieved in the field application of the processes.

Jan 1, 1995