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By Scott A. Stebbins

This Bureau of Mines publication presents a method for estimating capital and operating costs associated with the exploration, mining, and processing of placer deposits. To ensure representative cost estimates, operational parameters for placering equipment and basic principles of placer mining techniques are detailed.

Jan 1, 1987

By John J. McClelland

The Bureau of Mines conducted a study of longwall plow operations to identify dust sources and existing control technology. Three longwalls employing either the high-speed overtaking or conventional method of mining were surveyed. Principal operating parameters and on-site dust control technology at the time of each survey are described. Short-term gravimetric and instantaneous sampling results are discussed in detail. The relationship between longwall dust levels and dust control technology was examined.

Jan 1, 1988

By John P. McDonnell

Coal mine bounces and bursts are major problems facing U.S. mine operators. Bounces and bursts have the potential to inflict severe injury on mining personnel, damage equipment, and cause mine closures. High- stress conditions, at or near the working face, are the common denominator in the burst problem, If mine operators can locate high-stress and potentially burst-prone zones, they can then use stress-relief methods to control the burst condition. One method of locating the high-stress zone is the probe-hole-drilling or drilling-yield method. Probe-hole drilling is used frequently in Europe, the U.S.S.R., and Japan as a means for locating potential burst zones. Consequently, the Bureau of Nines performed tests in the laboratory and in a deep, burst-prone western mine to analyze probe-hole drilling. The in-mine method, very simply, involves drilling a hole into the coal seam and measuring the volume of cuttings obtained. A certain volume of cuttings can be expected from a certain diameter and length drill hole. A significant increase in the volume of cuttings means the zone around that particular hole is highly stressed. In-mine use of the drilling yield method has shown it to be a useful tool for locating highly stressed and potential burst zones. Results from laboratory testing confirm that high stress applied tri-axially to a cube specimen will cause a significant increase in the volume of cuttings from a small-diameter drill hole in the specimen.

Jan 1, 1988

By J. Dean Warner

In 1984 and 1985, as part of its critical and strategic minerals studies, the Bureau of Mines investigated lode and placer tin occurrences near Rocky Mountain (Lime Peak), in east-central Alaska. The lode occurrences consist of mineralogically complex, generally fault-controlled veins, and contain an average of approximately 0.05 pct Sn, as cassiterite. Beneficiation testing of two bulk samples of the vein material produced concentrates containing 65 and 59 pct of the total tin values at grades of 0.35 and 13.9 pct, respectively. Although as much as 30 million short tons (MMst) of mineralized rock containing up to 20 MMlb Sn may be present, the grade of these occurrences is too low to be considered economic at this time. Trace amounts of cassiterite were also identified in surface samples of glacial out-wash gravels collected along North Fork Preacher Creek, which partially drains the area of tin lode deposits near Lime Peak. Low tin grades in the samples do not account for the former erosion of a large volume of lode tin mineralization from near Lime Peak; higher tin grades may be present in gravels closer to bedrock.

Jan 1, 1988

By Mark S. Sanders

There is a growing awareness among mining professionals that the human factor plays a significant role in safety and productivity. Since the 1960's, the science of human factors, or ergonomics, has been making inroads into the mining industry, and a considerable amount of research has documented human-factor-related mining problems and solutions. This Bureau of Mines report is directed toward summarizing the application of human factors to improving safety, productivity, and the general physical and psychological working conditions of miners. The aim of this report is to familiarize the readers with the role of human factors in the mining industry and the benefits that can accrue by systematically applying available human factors principles and data. The text contains 10 chapters dealing with human, equipment, and environmental factors. Each chapter builds on the previous chapter; therefore, it is recommended that the chapters be read sequentially However, if the report is used as a supplemental text, say in a mining safety course, chapters can be assigned in any order to supplement other readings.

Jan 1, 1988

Mine waste and mine reclamation are topics of major interest to the mining industry, the government and the general public. This publication and its companion volume are the proceedings of a conference held in Pittsburgh, April 19-21, 1988. There were nine sessions (50 papers) that dealt with the geochemistry, hydrology and problems of mine waste and mine water, especially acid mine drainage. These comprise Volume 1. The nine sessions (43 papers) that dealt with reclamation and restoration of disturbed lands, as well as related policy issues, are included in volume 2. Volume 2 also contains the ten papers that pertained to control of subsidence and mine fires at abandoned mines. Poster session presentations are, in general, represented by abstracts; these have been placed in the back of both volumes.

Jan 1, 1988

Mine waste and mine reclamation are topics of major interest to the mining industry, the government and the general public. This publication and its companion volume are the proceedings of a conference held in Pittsburgh, April 19-21, 1988. There were nine sessions (50 papers) that dealt with the geochemistry, hydrology and problems of mine waste and mine water, especially acid mine drainage. These comprise Volume 1. The nine sessions (43 papers) that dealt with reclamation and restoration of disturbed lands, as well as related policy issues, are included in volume 2. Volume 2 also contains the ten papers that pertained to control of subsidence and mine fires at abandoned mines. Poster session presentations are, in general, represented by abstracts; these have been placed in the back of both volumes.

Jan 1, 1988

By R. J. Fantel

The Bureau of Mines investigated the resources, costs, capacities, market relationships, and short- and long-run supply of phosphate rock and phosphoric acid. The 206 mines and deposits evaluated in 30 market economy countries contain an estimated 35.1 billion mt of recoverable phosphate rock (demonstrated resource level). U.S. resources are sufficient to satisfy the domestic and export markets for phosphate products well beyond the year 2000. Because of resource depletion at current producers, however, new properties (with higher cost levels) need to be developed if U.S. production levels are to be maintained. Existing worldwide capacity can satisfy expected demand through the early 1990's. Expansion at existing mines or low demand growth could mean that no new property development will be needed before the late 1990's. Worldwide, almost $8 billion could be required for development of new phosphate rock properties between now and the year 2000, given 3-pct annual growth in demand. Most properties that could develop in the 1990's would require price increases of 20 to 50 pct to break even. To earn a 15-pct rate of return on investment, prices must rise to nearly double the present level of $24 to $29 per metric ton.

Jan 1, 1988

By Frederick K. Allgaier

This report presents the final data from a 5-yr Bureau of Mines study designed to determine the surface subsidence characteristics resulting from longwall coal mining in a geologic environment common to the Western United States, It includes a description of the geologic setting of the study site, the mine plan, measurement techniques, and results of the monitoring program. Measured subsidence values were obtained over four adjacent longwall panels- Major subsidence characteristics such as longitudinal and transverse profiles, angles of draw, time-related subsidence development, and critical width are discussed. The maxima subsidence value of 5.8 ft was 68 pct of the mining thickness. The average angle of draw was 30°, Subsidence at the center of the first panel continued for 46 months following undermining. The lengths of the longwall panels precluded a definitive determination of the critical width and maximum possible subsidence.

Jan 1, 1988

This report is a proceedings of a briefing recently sponsored by the Bureau of Mines at which Bureau personnel presented findings from their research efforts to improve steelmaking techology currently used in the United States. The papers contained in this report address many areas of concern to the iron and steelmaking industry. Among these are improving arc stability in electric arc furnaces, preheating ferrous scrap to reduce energy consumption, fluorspar substitutes in steel-making, basic steelmaking refractories, corrosion of iron-based materials, improvements in stainless steel acid pickling processes, recycling of stainless steel dusts and other wastes, and use of wastes as a source of zinc for electro/galvanizing.

Jan 1, 1988

By James R. Boyle

The Bureau of Mines initiated a program to address short-and long-term objectives of wetlands restoration as a option for reclamation of lands mined for phosphate. The short-term objectives were to identify a suitable wetland test site, initiate an extensive premining monitoring plan, develop an acceptable mining plan, and recontour and revegetate the test site. These goals were accomplished using a unique combination of expertise provided by Federal and State agencies and private industry. A 6.5-ha forested wetland with an associated streambed was offered by private industry as the test site. A premining monitoring program was established and carried out from May 1982 to October 1983. A control site was established to determine ecological changes unrelated to mining. Clearing and mining began in October 1983 and was completed in April 1984. Grading and streambed restoration was completed in February 1986. Revegetation of the site was completed in February 1987. The program to meet the long-term objective of postmining monitoring is described.

Jan 1, 1988

By Shail J. Butani

In 1986 the Bureau of Mines conducted a probability sample survey, Mining Industry Population Survey, to measure such employee characteristics as occupation; principal equipment operated; work location at the mine; present job, present company, and total mining experience; job-related training during the last 2 years; age; sex; race; and education. The population estimates are necessary to properly analyze the Mine Safety and Health Administration (MSHA) injury (includes illness and fatality data) statistics; that is, to compare and contrast injury rates for various subpopulations in order to identify those groups that are exhibiting higher than average injury rates. This report uses the survey's results to characterize the U.S. sand and gravel mining workforce from March through September 1986. Similar reports have been prepared for the metallic, stone, and nonmetallic mining industries, as well as for the entire metal and nonmetal mining (includes metallic, stone, sand and gravel, and nonmetallic industries) sector and the coal mining sector.

Jan 1, 1988

By Donna L. Anderson

The first section of this U.S. Bureau of Mines report includes a discussion of the navigational tasks performed by operators of mobile mining equipment, with the focus on the navigational information and guidance techniques required by continuous mining machine operators. Some previous research and attempts in remote and autonomous navigation of continuous mining machines are mentioned. Issues of research in autonomous navigation of various other mobile robots are presented, with attention focused on their applicability to a continuous mining machine navigating in the mining environment. Conclusions are stated on methods of automating the navigational tasks of a continuous mining machine, and a decision to concentrate initial attempts on the tasks of autonomous face navigation is defended. The second section of this report includes a presentation of the Bureau's proposed solution for autonomous face navigation of a continuous mining machine, which includes the employment of a mobile roof support as a reference for guidance in the face area, and a navigational guidance system for the continuous mining machine.

Jan 1, 1989

As part of its research on advanced mining technology, the U.S. Bureau of Mines emphasizes studies on in situ leach mining. This research enables the Bureau to develop technical information that can allow mining companies to adopt in situ leach mining methods. Research results should help to remove the technical and economic barriers currently hindering the development of commercial in situ leach mining operations. This report contains papers summarizing results of Bureau research on various aspects of in situ leach mining. A featured topic is the cooperative field experiment of the Bureau and Santa Cruz Joint Venture in a copper deposit near Casa Grande, AZ. Discussions in-clude an overview of the entire project, cost modeling, environmental permitting, laboratory core-leaching experiments, petrographic studies, and an evaluation of the geologic structure in the region. In addition, papers describe hydrologic modeling and geophysical studies of solution flow during leaching. Preliminary geochemical modeling studies are also summarized. A final paper describes a nonionic chemical additive with potential for significantly reducing the high costs of drilling in in situ leach mining.

Jan 1, 1989

By Paul C. McWilliams

The U.S. Bureau of Mines has, primarily through its contract program, used large-scale centrifuges to determine design criteria for tailing embankments. The centrifuge runs were made at two installations, the University of Cambridge, Cambridge, England and Sandia National Laboratories, Albuquerque, NM. The major problems considered were as follows: slope stability of embankments, modeling erosion and seepage, use of the phreatic surface level to ascertain the validity of centrifuge modeling, and the effects of compaction and weathering on a tailings embankment. This report summarizes the results of the four test series conducted at University of Cambridge and Sandia National Laboratories. A review of prior centrifuge applications to mining problems is included. Consideration is given to future centrifuge application to mining problems in both soil and rock mechanics.

Jan 1, 1989

By Thomas M. Barczak

State-of-the-art longwall roof supports provide effective strata control, but failures of these support systems still occur. To identify failure mechanisms and the impact these failures have on the safety of the support system, the U.S. Bureau of Mines has been conducting research on shield mechanics in the Bureau's unique mine roof simulator, as well as field studies of in situ support loading and investigations of longwall failures, Three types of failures are discussed: (1) inadequate support capacity, (2) structural failure, and (3) instability. Hypothetical situations with proposed courses of action and case studies of actual longwall failures are described. This information is intended to assist the Mine Safety and Health Administration (MSEIA) and industry mining personnel in safety evaluations of longwall roof support systems.

Jan 1, 1989

By George H. Schnakenberg

Automation of coal mining activities at the face offers improvements in worker safety, health, and productivity. Introduction of integrated computer-sensor systems to current mining machines will enable these machines to perform some of the most hazardous tasks through supervised teleoperation. The U.S. Bureau of Mines is pursuing the development of the enabling technology necessary to achieve this goal. The research program consists of both basic and applied research, each focused on the fundamental issues of computer and sensor technologies. Short-term research is directed to providing computer-assisted, remote supervisory operation of present underground equipment; the long-term goal is the development of progressively more intelligent mining systems. The research program includes a review of robotic machine and autonomous vehicle technologies and of current mining technology, which provides a base for developing innovative mining methods; research in navigation and guidance technology, emphasizing control of a continuous mining machine; research on coal-rock interface sensing technology for horizon control, and rib thickness control in highwall mining; the development of computer systems and hierarchical architectures for real-time control; and development of expert systems for machine system fault diagnostics and predictive maintenance. This report presents a brief background and the current status for each of these research areas.

Jan 1, 1989

By Jasinder S. Jaspal

Most of the underground coal in the United States is mined via room-and-pillar mining methods with continuous miners. These machines operate intermittently because they have to wait for shuttle cars to interchange positions. To overcome this discontinuity in shuttle car haulage and to realize the full production potential of continuous miners, the U.S. Bureau of Mines developed a multiple-unit continuous haulage (MUCH) system through a research contract with Jeffrey Mining Machinery Div. (JMMD). The MUCH system consists of 12 rubber-tired vehicles and a bridge conveyor. The rubber-tired vehicles are connected by a unique mechanical linkage system to form a 250-ft train. The mechanical linkage permits the vehicles to track-retrack the preceding vehicle in both inby and outby directions. The cut coal cascades from one vehicle to another until it is discharged on the section conveyor belt. The MUCH system provides continuous haulage to the continuous miner. The MUCH system was initially surface tested by JMMD. Subsequent extensive testing was conducted by the Bureau at its test facilities at Bruceton, P A. Deficiencies found during testing were corrected. This report summarizes initial tests by JMMD and subsequent extensive tests and evaluation by the Bureau.

Jan 1, 1989

By Pamela J. Watson

A novel technique has been employed by the U.S. Bureau of Mines to determine the zeta potential of particles for a far-reaching series of material types in a wide variety of baseline waters, both alone and with many different chemical additives. The materials tested ranged from naturally occurring Sioux Quartzite and Tennessee marble to commercially produced magnesium oxide bricks. The waters tested ranged from ultrapure distilled, deionized water to municipal tap water and mine-site water. The chemical solutions tested included inorganic additives, such as aluminum chloride (AICI3) and sodium chloride (NaCl); organic additives, such as dodecyltrimethyl ammonium bromide (DTAB); and nonionic polymers, such as polyethylene oxide (PEO). The results of precise zeta potential determinations have application in a large number of laboratory studies as well as in various mining and processing operations.

Jan 1, 1989

By Robert H. Peters

This report presents a literature review conducted by the U.S. Bureau of Mines. The review summarizes what has been learned from recent empirical studies of the relationship between mine safety and characteristics of miners, mine management, and mining companies. The review is based on literature published in the United States during the period from 1976 to 1988. In addition to summarizing the empirical findings, this report discusses the implications and limitations of these studies, and gives recommendations for improving mine safety. An annotated bibliography section appears in the appendix.

Jan 1, 2009