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Careful financial analysis of capital investments has always been a vital task in mining which is one of the most capital intensive sectors of the economy. Furthermore, mining costs have leapt ahead at an astonishing rate in recent years not just due to accelerated inflation, which affects everyone, but also due to the imposition of enormous costs of enviromental regulation and the continuing decline in ore tenor. Not only have unit costs risen, but the amount of effort expended to recover a pound of metal has increased due to the inexorable decrease in ore grades. New low-margin, high-volume mining investments place increasing importance on sound financial planning. Owing to the enormous investments involved, a greater share of individual corporate resources is committed to these projects than is normally the case in other industries. Thus, the consequences of failure are extremely grave, and a close examination of all inputs to the evaluation equation is clearly indicated.

Jan 1, 1979

By Winfield G. Wright, Philip L. Verplanck, Philip L. Hageman, Douglas B. Yager, Dana J. Bove, M. Alisa Mast

Geological, hydrological, and geochemical information synthesized in a Geographical Information System (GIS) for water and rock surrounding South and Middle Forks of Mineral Creek, northwest of Silverton Colorado, was analyzed to distinguish between the natural and the mining-related sources of metals to dace waters in the watershed An important natural source of metals to surface water emanates from a porphyry molybdenum deposit south and upslope from the Middle Fork of Mineral Creek. Interaction of surface and ground water with fractured, altered rocks and permeable, Quatemay-age surficial deposits produces downstream water quality that does not meet current State of Colorado water quality standards for metals and pH. GIS site characterization and three-dimensional modeling distinguish surficial deposits as volumetrically substantial, significant sources of naturally occurring metals that strongly influence water quality and complicate ongoing mine-site mitigation efforts. Our findings indicate that regional hydrologic and geologic information needs to be evaluated before realistic water quality guidelines are established and mitigation recommendations are confidently implemented.

Jan 1, 2000

By Kourosh Shahriar

The occurrence of rock falls in underground coal mines entails detrimental effects as fatal or non-fatal injuries on workers, stoppages in mining operations and breakdown of equipment. In this paper, a risk assessment approach on the basis of a decision analysis trend is employed in order to assess the possibility of and manage roof falls. Risk is then assessed by determination of likelihood of occurrence and the cost of consequences (outcomes). In this regard, collected real roof fall data from Tabas and Kerman coal regions comprising of several underground coal mines are used. It is concluded that the annual accidents due to the roof falls occurrence in the all investigated mines are so high that it is economically feasible to improve the support systems and to implement a suitable educational program as well as an accurate supervision and other elements of safety management.

Jan 1, 2009

By R. J. Beckman

This paper traces the history of mica mining in Alabama from 1870-1970. The decline of sheet mica production is noted and emphasis is placed on the more recent activity of scrap mica production and the development of the U. S. Gypsum Co. mica properties in Randolph County, Prospecting for weathered pegmatites of sufficient size to warrant development is a continuing challenge since most deposits are too small and all exhibit varying characteristics as to size, shape, and weathering. Quantity and quality of muscovite mica in the pegmatites is of utmost importance and its recovery during processing of the ore is described.

Jan 1, 1970

By Chi-shing Wang

The U.S. Bureau of Mines has been developing the mechanical roof pulling technique as a method for evaluating the effectiveness and the comparative advantages and disadvantages of various roof bolting systems, based on the characteristic responses of bolted nine roofs to a prescribed external loading system. Preliminary experiments were conducted in the Bureau's Safety Research Coal Mine using a 12-foot and a 16-foot-span test rig. The experiments have proved the capability of the test rigs and suggested the viability of the test method. This paper summarizes the test concept and the experimental results.

Jan 1, 1974

By Richard H. Olson

Talc is currently mined in the U.S. in six major districts. The size and depth of the ore bodies and their mineralogy dictate the types of products manufactured and the mining and processing methods which must be employed. The geology of the major deposits is well known and will be but briefly discussed The major emphasis will be placed upon the past history of the districts, the size and depth and configurations of the ore bodies, the ore mineralogy, and how all of these factors govern the types of mining and processing operations which may be employed in each of the districts.

Jan 1, 1984

By Gary E. McIntosh

This paper will discuss a U.S. Bureau of Mines project designed to assess and predict the impacts which surface coal mining will have on the regional shallow groundwater systems in the Powder River Basin. The primary objective will be met through the accomplishment of the following: (1) The design and establishment of a regional network for monitoring of shallow groundwater systems in the Basin. (2) Monitoring of the direction and rate of flow, water quality, and aquifer characteristics of the shallow groundwater systems. (3) Development of a regional groundwater simulation model with appurtenant subroutines to determine local effects.

Jan 1, 1978

By Paul Soros

A major share of the increase in the energy demands of Ontario province in the next decade will be supplied by bituminous coal mined in the U,S, To be competitive with alternative sources of energy, it is essential that the delivered cost of coal, inclusive of all transportation charges, be kept at a minimum. The Bessemer aid Lake Erie Railroad Company and the Pittsburgh and Conneaut Dock Company are currently building a shiploading terminal at Conneaut, Ohio, to service this tonnage, together with expected increases in coal consumption in the Eastern Lake Erie - Lake Ontario area, (see Fig, 1).

Jan 1, 1965

By C. E. Jordan

The U.S. Bureau of Mines investigated flotation hydrodynamics to improve the recovery of coarse phosphate. Fluid velocity profile measurements were used to characterize the hydrodynamics within commercial phosphate flotation cells and laboratory flotation cells. The effects of agitation, aeration, and pH on coarse phosphate recovery were measured in the laboratory flotation cells and correlated with the hydrodynamics measurements. Test results revealed that the agitation energy and aeration level had a significant effect upon flotation response. By optimizing these two parameters, 92 pct of the phosphate was recovered in a rougher flotation concentrate grading 28 pct P2O5?

Jan 1, 1994

By J. S. Jaspal

Mining of thin coal seams is both difficult and uneconomical. As a result, most of thin-seam coal reserves in the U. S. are not being mined. It is estimated that nearly 910 Gt (K. Unrug, 1985) of coal reserves exist in 355 to 710 mm thick seams. The Bureau is attempting to develop new techniques for mining 150 to 1065 mm thick coal seams. This paper summarizes the research work on existing thin-seam mining techniques, testing on small and full scale physical models of the Bureau slot mining concept, and computer modeling of the full-scale process.

Jan 1, 1992

By P. L. Sibrell

Previous research by the U.S. Bureau of Mines showed that autoclave cyanide leaching of used automobile exhaust catalysts for recovery of platinum group metals (PGM) was technically feasible. This work involves a more detailed investigation of the chemistry of the dissolution of PGM in cyanide solutions. The PGM species in solution identified by ultraviolet spectroscopy. Pt and Pd cyanide complexes were square were The planar in geometry, while the Rh complex was octahedral. The rate of dissolution of the PGM was also investigated using a rotating disk technique. Dissolution rates increased in the order of Rh, pt, and Pd, respectively.

Jan 1, 1994

By Wen L. Chen

The steam coal quality is less stringent than metallurgical coal quality. The steam coal is prepared either by cleaning full size range of raw coal or cleaning coarse coal only, leaving the fine coal raw. The latter scheme is more cost competitive. It is particularly applicable to U.S. eastern soft coal where low ash coal is concentrated in fine sizes. For raw coal size separation, a recently developed Rotating Probability Screen, developed by the British Coal Board, may be advantageously used for easy change of raw coal separating size and to avoid screen deck plugging when handling wet and clayey raw coals.

Jan 1, 1983

By B. J. Scheiner

The presence of organic materials in gold ores cyanidation. The presence of organic materials interferes with gold extraction by The carbon contained in the ore has been shown to adsorb gold cyanide complex from solution. Removal of the carbon content by roasting or chemical oxidation prior to cyanidation results in gold extractions of 85 to 95 pct. This paper by the Bureau of Mines, U.S. Department of the Interior, discusses how the mineralogy of the carbonaceous gold ores affects gold recovery by cyanidation. It also discusses the advantages and disadvantages of roasting and chemical treatment to render the ore amenable to cyanidation.

Jan 1, 1987

By Harold E. Goetzman, Blair R. Benner

The U.S. iron ore industry is located primarily in Northern Minnesota and Michigan's Upper Peninsula with one additional small plant in Missouri. There are currently some 10 plants operating that produce about 48 million tons per year of pellets. The major reagent use occurs in the three general areas of: flocculation, flotation and pellet additives. Minor areas of usage are for corrosion inhibition and dust suppression. Current practice as to types of reagents, consumption, and method of application are reviewed. The interaction of reagents with other parts of the process are discussed. Also included is a discussion of future reagent needs.

Jan 1, 1994

By T. Ruff, J. Steele

The lack of visibility near earthmoving equipment results in an average of five fatalities in U.S. surface mines each year. These accidents occur when a piece of equipment either strikes another vehicle or worker, or travels over the edge of an embankment. Researchers at the National Institute for Occupational Safety and Health have evaluated off-the-shelf proximity warning systems that sense obstacles near the equipment and provide an alarm to the operator. Limitations of existing systems have necessitated the development of new systems designed specifically for mining equipment, including a GPS-based proximity warning system and a computer-assisted stereovision system.

Jan 1, 2004

By Dwayne C. Kicker, Duk-Won Park

As the use of longwall mining increases in the U.S.. there is a need to better understand the stress redistribu- tions indicative of this method. To control high stress concentrations, the yield pillar concept has been developed. A physical longwall mine model has been designed to study the effect of yield pillars in deep mining. The model in- cludes sensitive stress measuring devices, a new excavating technique, and a new model material. This study includes the use of both regular and yield pillar systems and has successfully simulated the mode of stress change in chain pillars.

Jan 1, 1986

By Houston Kempton, David Atkins

Mining in semi-arid climates can produce environmental impacts that will not begin for hundreds of years, but once started, may continue for thousands of years. Pit lakes may eventually exceed toxicity thresholds as metals are evaporatively concentrated, and slow unsaturated flow through acid-generating waste can eventually load several kg-SO4/m2-yr to underlying water tables. U.S. regulations are poorly equipped to respond to delayed and long-term environmental impacts, delaying permits as operators and regulators grapple with uncertainty. Improved uncertainty analysis, additional long-term mitigation options, and explicit regulatory guidance offer solutions to this dilemma.

Jan 1, 2000

By M. E. Poad

In 1986, a cooperative effort by the Homestake Mining company, the U.S. Bureau of Mines and the University of Utah was initiated to determine shaft stability while recovering high grade ore in a nearby pillar. Premining finite element simulations indicated the shaft would remain in elastic ground. Six years have elapsed and, despite some initial concern during the first lifts, it appears that the bulk of the original reserve will be safely and profitably recovered. An integrated application of rock mechanics tools from laboratory testing through numerical modelling to mine measurements and observations contributed substantially to the operational success of the project.

Jan 1, 1994

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 E. William Rossi, Audrey F. Glowacki, Richard L. Unger

The U.S. Bureau of Mines has developed a graphics-based computer model to assess operator visibility for continuous miners, shuttle cars, and scoops. Using digitized drawings of the machine, the program can analyze visibility for both 5th percentile female and 95th percentile male operators. This model was used to predict 95th percentile male operator visibility for two shuttle car designs. These results were then compared to those obtained from a manual assessment of visibility using the actual shuttle cars. The methods showed good correlation except for several cases which were attributed to imprecise digitization of the machines.

Jan 1, 1992