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By Ernest J. Conway

This report presents engineering drawings for six material handling devices for underground coal mines. The devices were designed under a U.S. Bureau of Mines program to reduce injuries from material handling during mine and equipment maintenance. The six devices are (1) scoop-mounted 1411: boom, (2) swing-arm boom, (3) heavy-component lift-transport, (4) mine mud cart, (5) container-workstation vehicle, and (6) timber car. Each device is described briefly, and recommendations are made concerning the design of new devices.

Jan 1, 1989

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

By Daniel Ng

The U.S. Bureau of Mines-Michigan Technological University mine ventilation mainframe program was successfully adapted for execution in a personal computer (PC). The hardware requirement can be as modest as 256 kilobytes (33) of random access memory (RM) and two floppy disk drives. A version compiled for a PC possessing 512 Kb RAM has arrays dimensioned to accommodate 512 separate mine airways and junctions, and it contains all the features and capabilities of the original version. It has successfully analyzed all the ventilation networks tested, including a very large commercial mine (404 airways, 237 junctions, and 5 fans). In all cases the PC version produced practically identical results as obtained from the mainframe computer. In all respects, the PC version performed the same as the mainframe version with the exception of execution speed When a numerical coprocessor is employed, execution time can be reduced by more than 50%.

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 Thomas M. Barczak

The U.S. Bureau of Mines has been conducting research to optimize the design and utilization of mine roof support systems. An objective of these efforts is to evaluate the mechanical and structural responses of various mine roof support systems under simulated load conditions in the Bureau's mine roof simulator. Underground studies are also made to evaluate the in situ behavior of support structures. The purpose of this report is to document practical applications for longwall face and gate road supports that have resulted from these studies. This report is not intended to be an all-inclusive manual on every aspect of support utilization, but it does provide a comprehensive assessment of practical considerations relating to the mechanical and structural behavior of these support systems. Forty-six recommendations are made to provide assistance to mine operators in the testing, selection, and utilization of longwall face and gate road supports. Many of these recommendations offer innovative solutions to everyday problems faced by mining personnel in the control of ground in longwall 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 Robert H. Peters

The U.S. Bureau of Mines has prepared this report on strategies for maintaining high job attendance among underground coal miners because high absenteeism is a threat to miners safety and seriously hampers productivity. A substantial number of research studies on the effectiveness of various strategies for reducing absenteeism among the employees of nonmining industries have been reported in the literature. These strategies have aimed at improving job attendance through one or more of the following: (1) improving employment procedures, (2) overcoming problems that adversely affect one's ability to attend work, and (3) increasing miners motivation to attend work. Many of these strategies appear applicable to the mining industry, and are reviewed in the first half of this report. The second half of this report describes how one could develop and implement a program for maintaining high attendance at underground coal mines. The steps include: measuring and evaluating attendance levels; formulating attendance goals and an absenteeism policy; developing and implementing an attendance promotion program; and periodically going through the preceding steps known as recycling.

Jan 1, 1989

By Robert L. Virta

This U.S. Bureau of Mines paper discusses the structure of the talc industry, talc production, processing of talc ore, applications and demand for talc, and the outlook for the talc industry.

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 Donna L. Anderson

This U.S. Bureau of Mines report describes a system to determine the position and heading of a continuous mining machine during the maneuvers required at the face area of a mine. The system consists of commercially available angular position sensors and a computer interface developed and tested at the Bureau. The sensors employed are laser-based scanning devices that report the angular location of retroreflective targets within their 90° field-of-view. The targets are mounted on the continuous mining machine; the laser scanners are mounted on an external reference structure. The computer interface consists of a single-board computer-controller programmed to gather and process the angular position information, and to calculate the machine's position and heading relative to the reference structure. A sensor fusion algorithm will be incorporated into the computer interface programming to increase the accuracy and reliability of the system.

Jan 1, 1989

By John J. Sammarco

The U.S. Bureau of Mines has developed a regulated, intrinsically safe, rechargeable power supply for portable electronic equipment for underground use. The regulated output is ideal for microprocessor power requirements and is suited for operation in hazardous environments. Two rechargeable, sealed batteries are contained within the power supply. Provisions are made to use an external source of power if these batteries fail. Provisions are also made to charge these internal batteries when needed. The circuit is composed of three main circuits: the main regulator circuit, the input protection circuit, and the output protection circuit. The main regulator circuit provides remote voltage sensing, current sensing, fault monitoring, and internal thermal protection. The input protection circuit checks for excessive input current and low battery conditions. The output protection circuit contains two overvoltage detection devices. Schematics, a parts list, and a calibration procedure are provided in this report to enable readers to fabricate the power supply.

Jan 1, 1989

By J. C. Duchon

The U.S. Bureau of Mines is conducting human factors research for the purpose of reducing accidents and improving the person-machine interface found in surface and underground mining operations. Miners are exposed to a variety of environmental stressors, e.g., extreme heat, noise, vibration, and adverse illumination, throughout the workday. Exposure to these environmental stressors has been noted in the literature to affect performance on vigilance tasks. Since impaired performance at vigilance tasks can lead to industrial accidents, further investigation of the effects of environmental stressors on human performance is warranted. A brief description of the environmental conditions present in the mining workplace is followed by a review of experiments dealing with the effects of environmental stressors on vigilance task performance. The applicability of past research to actual mining operations is considered.

Jan 1, 1989

By Frank T. Duda

A U.S. Bureau of Mines interactive FORTRAN computer program can screen explosion-proof enclosures intended for underground service. The program incorporates important information and criteria to assist enclosure manufacturers and Mine Safety and Health Administration (MSHA) personnel by providing a first-order approximation of rectangular explosion-proof enclosure characteristics prior to actual certification testing. The program uses information and data that can be retrieved automatically during program execution. The program also performs the calculations for a series solution algorithm and various equations to evaluate the enclosure for both a static internal pressure and an internal explosion. The program writes the intermediate and final calculations and information concerning the status of the screening process to a summary file on a floppy disk. One data base contains MSHA certification requirements given in the Code of Federal Regulations (30 CFR 18). A second data base contains material properties of acceptable construction materials and weld joint efficiencies. A series algorithm determines bolt and cover stresses for a simply supported rectangular cover with arbitrary bolt locations. Limit and yield line analysis is used to calculate the strength of body panels.

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

By Thomas J. Albin

U.S. Bureau of Mines research has found that maintenance of surface mining equipment is involved in slightly more than one-third (34.1 pct) of all surface mining accidents. Two groups of machines, haulage trucks and power shovels, accounted for over one-half of all surface mining mobile equipment maintenance accidents in 1978-84. Maintenance work-time histories for these machines were compared with accident records to identify the most hazardous-to-maintain systems within the machines. Recommendations to reduce the accident risk associated with maintenance of these hazardous systems are presented.

Jan 1, 1990

By John J. Sammarco

The U.S. Bureau of Mines is conducting research into computer-assisted mining, which requires investigation of new techniques for development and application of computer-based technologies. Today's technology can require significant effort in software development, as has become evident in the early stages of this Bureau research. Technologies for software automation, such as computer-aided software engineering (CASE), are available. This report explores CASE, its general features, and its importance in software development. Information is presented to assist in selection and application of the variety of CASE tools and methods for automating various stages of software development. When evaluating CASE for use, it is important to examine tools that support an organization's existing methods of software development. Support for existing hardware platforms must also be examined. Merely selecting a "good" CASE tool does not insure success. Thorough evaluation of implementing CASE is also critical. Subjects to evaluate for CASE implementation include organization culture, support from management and end users, training resources, and pilot projects. Organizations that benefit the most from CASE evaluate CASE features with respect to their needs and they properly implement CASE.

Jan 1, 1990

By Louis J. Sousa

In November 1989, the U.S. Bureau of Mines sponsored a 2-day conference to stimulate thinking and discussion about changing materials technologies and implications for the Government's materials information programs. On the first day of the conference, speakers provided overviews of developments occurring in each of the major materials groups. Emerging technological developments, applications, economic and national defense significance, intermaterial competition, and potential market growth in advanced plastics, polymer composites, ceramics, metals, and electronic materials were described. In general, the speakers forecast advanced materials market growth rates in excess of overall gross national product (GNP) though high costs will tend to limit growth outside of aerospace, defense, electronics, medical equipment, and other typically high value-added businesses. On the second day, a wide range of speakers representing several facets of the materials community described how advances in materials technology are creating a need for new types of data, statistics, information, and analysis. Reflecting the speakers' broad range of organizational, professional, and personal perspectives, an array of information needs was identified. Most requirements, however, seemed to fall into one of five major categories: Federal materials research activities, material standards, market and economic information, health and safety, and public policy.

Jan 1, 1990

By D. G. Willard

The U.S. Department of Interior, Bureau of Mines has evaluated the potential resource and annual availability of cobalt from 27 deposits or districts in 11 market-economy countries. More than 95 pct of primary cobalt production from market-economy countries, mainly byproduct output from copper and nickel operations, was analyzed. Approximately 1,200,000 mt of cobalt is potentially recoverable at the demonstrated resource level. Very large additional resources exist, especially in laterite deposits, but are at the inferred level. The producing operations evaluated in this study are expected to produce about 19,000 mt of cobalt in 1989, significantly less than the available capacity of about 31,000 mt. More than 14,000 mt per year of cobalt is produced from copper-cobalt deposits in Zaire and Zambia, of which 11,000 mt can be produced at a copper price of $O.60jlb or less with a O-pct discounted cash-flow rate of return (DCFROR). Approximately 4,400 mt of cobalt is produced annually from nickel-cobalt deposits in six countries, of which about 1,800 mt (in Canada and Brazil) could be produced at a nickel price of $1.50jlb or less at a D-pct DCFROR. Approximately 200 mt per year of cobalt is produced from a cobalt mine in Morocco. Most of the evaluated nonproducing operations and prospects that could potentially produce cobalt as a principal product or byproduct would require a total cost (including a 15 pct-DCFROR) significantly exceeding January, 1989 market prices of the principal commodities. Principal-commodity dependence, transportation routes, cobalt toxicity, and other issues that could affect the availability of cobalt are addressed herein.

Jan 1, 1991

By Russell J. Foster

Many important materials are derived entirely or partially as byproducts of primary copper, lead, and zinc production. This U.S. Bureau of Mines report examines the collective role of byproducts with regard to the economics of domestic mineral production, and their individual significance in terms of dollar value, end uses, and strategic considerations. The study also analyzes circumstances that have affected the competitiveness and structure of the U.S. copper, lead, and zinc industries, and factors that impact byproduct availability. These factors include production capacity at smelters and refineries, process technology, changing sources and composition of ores, regulations, foreign ownership, and byproduct demand and price. Policy considerations regarding stockpiling, regulations, and research are assessed.

Jan 1, 1991

By Jay C. Hanson

Various electrical and electromagnetic (EM) geophysical techniques are currently being evaluated by the U.S. Bureau of Mines for their effectiveness in the detection and monitoring of electrically conductive (1 to 5 S/m) lixiviant (leach solution) to depths of 600 m, either above or below the water table. These techniques include magnetotellurics (MT) , controlled source audiofrequency magnetotellurics (CSAMT), resistivity and focused resistivity, ground-penetrating radar (GPR), frequency-domain electromagnetics (FEM), and time-domain electromagnetics (TEM). Of these techniques, TEM may be the most effective, but CSAMT and focused resistivity also hold promise. Geophysical computer modeling of the borehole TEM technique was conducted based on an idealized geoelectric section (layered earth) with characteristics based on the Santa Cruz porphyry copper deposit near Cas a Grande, AZ. Layer resistivities and thicknesses were obtained from geophysical data and geologic logs available from the site. Modeling of borehole TEM in both preleach and during leach situations was conducted. Simulating the TEM method using computer modeling proved to be encouraging since there were substantial differences between leached and nonleached responses. The modeling does not prove the effectiveness of TEM in the field, but does indicate that detection of deep lixiviant zones is theoretically possible.

Jan 1, 1992