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By Frank L. Wideman

THE TREND towards larger quantities of waste in materials handled at metal and nonmetal mines (excluding fuels) continued. A gain of 10 percent from 1962 in the tonnage of waste removed in mineral operations reflects the kind of technological problems being encountered. Technology has a major role in the mineral industry in the task of supplying raw materials obtained from resources occurring beneath the surface of the earth and used in manufacturing commodities essential to modern living. Changes in technology are often brought about by such factors as variations in economic conditions, differences in physical properties of raw material and changes in mineralogical compositions of ore. Mining is usually begun on the richest and most accessible of known deposits, and when these are exhausted, is continued with leaner ores or with less accessible deposits that are either lying at greater depths or are more remote from markets. The increasing difficulties of extraction and depletion of reserves are offset by improvements in extraction technology, improved transportation, and exploration for new deposits. Although depletion has prevailed at many individual mines and in many districts, technology has been the means of providing for increasing demands of an expanding economy with adequate supplies of minerals despite either the changing character or decreasing grade of certain ores. This has been accomplished by various methods applicable to minerals. Among the implements of technology are utilization of lower grade or more complex refractory ores by mass mining, concentration, processing, recovery of byproducts, and mechanization. Better methods to find concealed deposits or to penetrate to greater depths also have been helpful in maintaining a supply of particular minerals.

Jan 1, 1964

By E. Rupprecht, J. Volkwein, K. Cashdollar, R. Gürtunca

The National Institute for Occupational Safety and Health (NIOSH) mining research program at the Pittsburgh Research Laboratory (PRL), includes the areas of coal mine dust control and monitoring, and explosion prevention. One very important project at PRL is development of a continuous recording person-wearable respirable dust monitor. This Personal Dust Monitor (PDM) is a respirable dust sampler and gravimetric -equivalent analysis instrument that is part of a belt-worn mine cap lamp battery unit. Prototypes were successfully tested in the laboratory and in four underground coal mines. The PDM testing demonstrated that it was convenient to wear and use, robust, and provided accurate and timely data. NOSH is also conducting research in the program area of coal mine explosion prevention, suppression, and mitigation. Aspects of this research program include: full scale explosion research, laboratory scale research, frictional ignition of methane, mine ventilation seal construction, prediction of coal mine methane emissions, mine monitoring systems, flame cutting and welding operations, spontaneous combustion, and emergency preparedness.

By Robert F. Chaiken

Burnout Control is a process developed by the U.S. Bureau of Mines for accelerating the burning of wasted coal fires in situ, while at the same time controlling the heat and fumes produced. The Albright fIre project is a fIrst fIeld trial of Burnout Control as applied to a coal waste bank. An exhaust ventilation system was designed and constructed and then operated over a 1-year period at the site of an existing abandoned mine land fire near the town of Albright, WV. While predicted exhaust gas temperatures of 900° C and thermal power levels of 5 MW were achieved at 20-to 3O-in H20 vacuum levels, problems were encountered with engineering designs, equipment breakdown, and fuel-rich combustion that curtailed the time period of satisfactory operation. Effective afterburning of the exhaust gases (as they were drawn from the bank) corrected the problems associated with combustion stoichiometry and led to high thermal outputs. It is believed that with (1) improvements in engineering design and construction, (2) better control of the afterburning process, and (3) the use of conventional stack gas air-pollution controls, Burnout Control can be applied successfully to a coal waste bank fire.

Jan 1, 1991

By J. P. Morris

An experimental blast furnace in normal operation was quenched by substituting cold nitrogen for the hot blast air. More than 2,200 samples from the stack, bosh, and hearth were taken; 500 of these were selected for detailed analysis. Deductions are made as to the patterns of burden movement and gas flow; the reduction of iron oxides, including a comparison of ore and sinter; and the behavior of sulfur above the smelting zone. Metal and slag beads from the bosh were analyzed, as were samples from the hearth metal and slag. A brief description of a petrographic examination of the quenched burden is included.

Jan 1, 1963

By Mark S. Sanders

This report presents a summary of the work reported by Sanders and Kelley (1981). A task analytic approach was used to define information requirements and visual features which served as sources of information. Information requirements were prioritized and the location of visual features determined. From this analysis, visual attention locations, containing one or more important visual features, were indentified. The visual attention locations are contained in this report. A procedure was developed for assessing whether operators in existing machines could be expected to see the visual attention locations. The procedure makes use of a Human Eye Reference Measurement Instrument (HERMI) designed for this project and an outside-in photographic procedure for documenting compliance with the recommendations. A sample of continuous miners, shuttle cars & scoops were used to test the procedure. Illustrative results are presented in the report.

Jan 1, 1981

By Stephen C. Tadolini, Dennis R. Dolinar

The risk of injury caused by minor roof falls continues to increase in underground mining. Most ground control injuries result from small rock falls that occur in a supported area, but do not involve the failure of the support system. In the roof, these are the "skin failures" that occur between previously installed primary or secondary bolting systems. To minimize skin failures and the associated accidents, several devices were designed and tested in the laboratory to maximize stiffness, minimize material thickness and weight, and ease material storage and handling on roof bolting machines. The goal of this project was to design and evaluate devices that can be installed with traditional primary or secondary roof supports, and that are easy to handle/install under temporary or previously supported roof.

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 Galen G. Waddell

The Deep Creek zinc and lead mine afforded an excellent example of a relatively small underground mine operation that approached the low mining costs of large, highly mechanized mines. An open stope mining method incorporating sublevel benches and vertical long holes was used (fig. 1). Detailed descriptions are given on the exploration program, stope development, stoping procedures, and pillar removal. Pressure grouting was used to check the inflow of water and thus prolong the life of the mine. Statistics on mining costs and on electric power consumption, haulage from mine to mill, and milling costs are included.

Jan 1, 1963

By C. R. Summers, J. N. Murphy

In response to the Coal Mine Health and Safety Act of 1969, mandatory noise standards have been developed that specify time-noise limits of mine personnel exposure. Most affected by elevated noise levels is the pneumatic roof bolter operator, both in terms of levels near or in excess of 115 dbA and in terms of length of exposure. Therefore, the principal emphasis of this Bureau of Mines report is on pneumatic drill noise control. It is not the intent of this report to suggest any drill redesign; instead, methods are suggested to reduce the noise level by complementing existing machines. An integral muffler system and a separate muffler system were tested in an attempt to lower pneurnaric drill noise levels. Pneumatic drills, when new, operate at about 115 dbA when drilling in sandstone. Using the drill muffler systems, it was possible to decrease the noise level of a 115 -dbA s rope drill to approximately 100 dbA.

Jan 1, 1974

Longwall minim; is a highly mechanized, high productivity mining method that is finding increasing applications in coal. Although the method would be highly advantageous in certain hard rock mining applications it cannot be applied in hard rock because no suitable cutterhead exists for such materials. The wedge longwall cutterhead is a, roller cutter device that is wedge-shaped, with cutters arranged to eliminate the very large normal force ordinarily required to cause such cutters to penetrate hard rock. However, the wedge geometry cannot be extended to a point: special nose cutters are needed to open a narrow slot for the wedge. This report describes the design, fabrication, and successful field testing of these critical nose cutters.

Jan 1, 1974

By Francis E. Federspiel

In 1984 and 1985, at the request of the U.S. Forest Service, the U.S. Bureau of Mines examined the 87,720-acre South Boise Yuba study area (formerly known as RARE II Wilderness Recommended area I-4553) to evaluate mineral resources. The study area and additions are in Blaine, Camas, and Elmore Counties, 10, about 60 mi east of Boise. Granitic rocks of the Cretaceous age Idaho Batholith occupy the western two-thirds of the study area. A Tertiary age granitic complex has intruded, and broken into small blocks, Paleozoic age sedimentary rocks in the eastern third of the study area. Tertiary Challis Volcanics overlie both of these rock types. Principal mineralized structures are gold-and silver-bearing quartz veins and shear zones trending northwest to easterly in the Cretaceous granitic rocks. Copper, lead, and zinc are accessory metals in many mineralized structures.

Jan 1, 1987

By Steven W. Schmauch

The U.S. Bureau of Hines conducted e mineral resource survey of approximately 232,000 acres in part of the Humboldt National Forest, Nevada, during 1989. About 7S percent of the study area was covered with mining claims. About 1,800 samples were collected end analyzed for 16 elements. Geologic structure, including thrust faults, is the most important factor in the localization of mineral deposits in the study area. The Independence mine (formerly Jerritt Canyon), Big Springs, and Wood Gulch are the most well known active properties, all developed on large, low-grade, disseminated gold deposits. These deposits have produced almost 3 million ounces of gold and are known to contain more than 8 million ounces of gold. At least 10 barite deposits in the south end of the range have had significant past production and contain 0.2 million tons of resources. Numerous precious and base metal targets have been identified and in some cases quantified during this study.

Jan 1, 1992

By William M. Hinton

This report describes the approach, procedures, and results of a program to develop training materials for roof bolter operators. The objective of the program was to design and produce a training sequence which would prepare roof bolter trainees for job performance. Data was collected and analyzed using the general procedures of Instructional Systems Development (ISD). Input data came from a previous roof bolter training analysis program. This data was expanded and structured through a series of ISD steps: objectives hierarchies, media selection, syllabus, lesson specifications, and train¬ing materials development. The resulting program consisted of an ordered sequence of 15 lessons. The media mix for the 15 lessons included lectures, slide-tape lessons, and hands-on instruction using operational roof bolters. Contents of all lessons were reviewed and approved by the Bureau. The key recommendations were to (1) validate the materials and measure relative effectiveness of media formats; (2) survey mines for training resources and conditions - match materials to user capabilities, rather than selection state of the art technology/media; (3) develop job performance aids (JPAs) rather than simulators; (4) create a style/media/JPA development guide for use in future projects of this kind.

Jan 1, 1982

By M. A. Trevits, J. E. Urosek, A. C. Smith, M. P. Valoski

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

By H. D. Kline

This paper describes the methods of mining and washing brown iron are in 1957 at the Sawyer mine, leased by Wayne County Mining Co., and the Fore mine, leased by Four Mining Co., both in southern Missouri; it is one of a series prepared by the Federal Bureau of Mines on mining and milling methods and costs in various districts of the United States. The Sawyer mine is in Wayne County, about 10 miles north-northeast of Williamsville (fig. 1); the Fore mine is in Howell County, about 20 miles southwest of West Plains (fig. 2). Both are open-pit mines from which the crude are was upgraded by washing and hand-sorting to produce are of grade and quality suitable for sale to operators of iron and steel furnaces. The operations described are typical of many others that produce or have produced marketable brown iron are from small sedimentary deposits, several hundred of which outcrop on the crests or hill sides of southern Missouri (fig. 3). The 1957 production of marketable brown iron are by 40 separate operations in the southern part of the State was 281,427 wet long tons, valued at $1,637,243. Production from the Sawyer mine that year was 17,000 dry long tons of washed are, and from the Fore mine, 20,816 dry long tons.

Jan 1, 1960

By R. R. Faddick

Properties of coal-water slurries were studied in two separate phases: a rheological phase and a pipeline phase. The purpose of the study was to investigate the rheology of fine coal slurries to determine the effect of fine particles in a coal-water mixture on the economic and operational aspects of a slurry pipeline. The slurries consisted of 6x10, 100x200, and 200x0 mesh coal in water. A fourth slurry consisted of a mixture of the 6x10 and 200x0 mesh coal. Brookfield and Stormer rotational viscometers were used to obtain or simulate rheograms for a range of fine coal concentrations, temperatures, and particle sizes. All the slurries were pumped through a 1-inch diameter acrylic pipe. The fine coal slurries were found to encompass four distinct rheological models. The narrow size distribution of the coal slurries was apparently responsible for the high pipewall friction losses, more so than the particle size. A scale-up method applicable to Bingham plastics was found satisfactory for predicting pipeline headlosses of fine coal slurries from rheology data.

Jan 1, 1974

By V. B. Dale

San Manuel has been a modern prodigy from its inception to its present status as a block-caving operation producing 33,000 tons per day. The deposit was discovered, prospected, and developed with modern techniques, and nearly all planning was done from results of an extensive drilling program through an average overburden of 670 feet. The Federal Government had a prominent part in the discovery and primary development of San Manuel. The first 17 holes were drilled by the Bureau of Mines, and discovery of the large, low-grade, disseminated copper deposit is credited to the Bureau. A loan fund of 94 million was granted through the Reconstruction Finance Corporation to the San Manuel Copper Corp. for development of the deposit and erection of concentrating and smelting facilities. Then, while the mine was still being developed, the Defense Materials Procurement Agency contracted to buy a large amount of copper at a pegged price.

Jan 1, 1962

By J. A. Lamonica

The Bureau of Mines conducted an environmental noise survey to determine the noise levels to which underground coal mine employees are exposed, to evaluate noise survey techniques and equipment, and to compare noise exposures using two criteria, Walsh-Healey and CHABA, for determining allowable exposures that were under consideration for the Federal Coal Mine Health and Safety Act of 1969- Time study techniques and Bureau-approved standard sound level meters were employed. The shift exposures of 20 percent of the miners studied were in excess of the safe standards established by both criteria. The shift exposures calculated using the Walsh-Healey criteria were greater than those calculated using the CHABA criteria owing to the intermittent nature of the exposure. Ultimately the CHABA criteria were rejected, and the Walsh-Healey criteria were adopted.

Jan 1, 1971

By L. C. IlsLey, M. W. Von Bernewitz

"Introduction.Several hundred thousand open lights are daily carried in coal mines of the United States, each lamp being a menace to life and property through fire or explosion. They have been responsible for many disasters in the past, and will be again. Flame safety lamps have been available for over a hundred years, but during the last ten years safe and practical electric lamps have been perfected. These have eliminated many of the flame safety lamps, and in a few mines have replaced open flame lamps. But there are still more than twice as many open lamps as electric lamps in our mines, and the open lamps should be discarded in favor of an approved type of electric lamp. There are several electric miners' lamps which have been approved by the Bureau of Mines for safety and efficiency, give good light, and are easily maintained and carried, some flame safety lamps will always be used, hut mostly for detecting gas; although they might be supplanted if some simple, reliable, and cheap gas detector were developed.Explosion Hazards from Open Lights.An open light and gas*** constitute a vicious hazard; while if there be coal dust present in the vicinity the consequences are multiplied many times. An open light and black blasting powder also constitute an explosion hazard, vividly attested by several serious disasters."

Jan 1, 1924

By S. Gallagher, A. G. Mayton

Back injuries account for a high proportion of lost workdays in the mining industry and are a leading cause of disability in mine workers. Two risk factors for low back injuries are manual lifting and whole-body vibration exposure when operating mobile equipment. Recent research has shed light on possible mechanisms through which low back injuries may occur, and the results of these studies can be used to improve the design of lifting tasks and seats to decrease injury risk. This article discusses recent research results and how this knowledge can be leveraged to reduce the risk of low back pain.