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By K. C. McMahon

This report is the result of the engineering efforts performed by the Mining Equipment Operations of FMC to develop methods of automating a continuous miner. This work was done as part of modification number three of the contract for the development of a miner/bolter system. As the demand for energy places an ever-increasing pressure on the coal mining industry to produce more coal, methods for underground mining which will increase productivity with a con-current increase in safety are being actively sought. Removing the machine operator from his station on the continuous miner and placing him at a safer location behind the machine while retaining his control functions via an umbilical cable or a radio link was an important first step. However, the problems of poor visibility, no control "feel", and the judgmental problems of controlling the sump distance and the shear limits have not been conducive to the productivity increase that is desired.

Jan 1, 1975

By Jeffrey A. Aldinger

This U.S. Bureau of Mines report presents an analysis of surface coal mining accidents involving mobile equipment for the years 1989 through 1991. Mobile equipment is defined as haulage trucks, front-end loaders, bulldozers, scrapers, and road graders. These five pieces of mining equipment accounted for 20 pct of all surface coal mine accidents and 41 pct of the fatalities. The general discussion of these accidents covers the accident causes, the primary activity of the accident victims, and other contributing factors. A more detailed analysis of accidents associated with each piece of mobile equipment is also provided. This report will provide mine managers and mine safety personnel with a better understanding of the hazards associated with mobile mining equipment. It identifies where improvements in mobile equipment safety can be made and those areas requiring additional safety emphasis, such as safety training, work procedure changes, or engineering changes to the equipment or work environment. The analysis was performed by a team of researchers using accident data and narratives provided by the Mine Safety and Health Administration.

Jan 1, 1995

By Fraser M. Walsh

The objective of this program was to determine by laboratory experiments the kinetics and mechanics of the reactions that produce acid in coal mine drainage. The program was divided into three phases: In Phase I, five coil mines, representative of Appalachian coal mines, were chosen for sampling and an experimental design was identified suited to accomplish the program objectives. In Phase II, the five mines were sampled and test protocols applied. The results showed most pyrite weathering to be based on oxidation in the presence of water. Iron bacteria, especially Thiobacillus ferrooxidans, catalyzed the rate of pyrite weathering by a factor of three. An increase in initial iron concentration in a system that modeled the nine environment acted to inhibit bacterial catalysis of weathering. In Phase III, five tailings piles were sampled and the material obtained was used to evaluate this method of bacterial catalysis inhibition. The evaluation verified method effectiveness; inhibition of over 80% of the release of weathering products was observed.

Jan 1, 1982

By J. R. Thoenen

In Progress Rerort 1,4/ a number of facto were demonstrated and conclusions drawn from experimental tests and records made during commercial blasting operations at a number of quarries. For example, the tests showed (1) that vibrations received on outcrops were of comparatively

Jan 1, 1938

By Earl C. Redman

The Juneau Gold Belt, centered on Juneau and approximately 120 miles long by 10 miles wide, stretches from Berners Bay on the north to Windham Bay on the south (fig. D-l). Access within the Juneau Gold Belt is provided by the Glacier, Thane, and North Douglas Highways. The Glacier Highway extends northwest from Juneau for approximately 40 miles to Echo Cove, and the other two roads end 5.5 miles southeast and 12.6 miles west from Juneau, respectively. None of these roads connect with other highway systems and access to other areas is restricted to airplanes, the State ferry system, and commercial barge lines. BUREAU ACTIVITIES The majority of lode gold produced in Alaska came from the Juneau Gold Belt portion of the Juneau Mining District. To evaluate the economic potential of the Gold Belt, the Bureau located 173 mines and prospects within the area. A total of 263 ad its and shafts were found and 56,650 feet of underground workings were mapped. The Bureau collected and analyzed 1,557 samples during the study. In addition, considerable detailed geologic map-ping was done in the vicinity of the mines and prospects from which ore control models were developed.

Jan 1, 2012

By R. E. Gray

[The purpose of the study is to investigate cases of subsidence over abandoned mined-out areas of the Pittsburgh Coal identified from published and unpublished sources and to determine through a consideration of the geology, topography, climate, mining activity, and evidence at ground surface, what mechanisms control subsidence .and under what circumstances it takes place. The study wan performed it two phases, the first to identify all documented incidents of subsidence in mined-out areas of the Pittsburgh coal Region; and the second, to study a particular portion of the region in detail, collecting pertinent data relative to the sites within, characterizing roil the nature of the subsidence and its economic consequences, and determining the applicability of the findings to other areas whore similar problems with the collapse of abandoned miner have been encountered.]

Jan 1, 1977

By A. C. Fieldner

This report is the fourth of a series of annual summaries of research and technologic work on coal by the Technologic Branch of the Bureau of Mines. The coal research program of the Bureau has been broadened and made more flexible to adapt it to changing conditions and needs of the coal industry, and as a result information as to the properties and composition of coal has been increased and new and improved practices in mining, preparation, and utilization of coal have been devised. The present

Jan 1, 1940

By Joel N. Van Sant

THIS REPORT describes the occurrence, mining, and use of refractory clay in Colorado within Region III of the Federal Bureau of Mines, which includes the States of North arid South Dakota, Nebraska, Wyoming, Colorado, Utah, New Mexico, and Arizona. Field work by the Bureau of Mines, United States Department of the Interior, included examination of active and abandoned refractory-clay mines as well as a reconnaissance survey and sampling of numerous clay-bearing formations exposed in Colorado. Information from the survey and the sampling will help guide private industry in its search for virgin sources of refractory clay. Library research of published and unpublished reports from various Federal, State, and private sources was conducted during the early phase of the investigation. Most of the refractory clay mined in the Denver-Golden district of Colorado is not used for refractory purposes but is blended with other clays in the manufacture of structural clay products. The predominantly flint-clay de-posits in the Pueblo and Fremont County districts are mined and utilized chiefly in fabricating refractory products.

Jan 1, 1959

By L. A. Neumeier

The Bureau of Mines investigated hot-rolling and forging characteristics of experimental ductile iron castings, both sand and permanent-mold, made with charges containing up to 70 pct foundry pig iron and 95 pct steelmaking pig iron. Between 1,550° and 1,950° F, most castings could be rolled to 90-pct reduction or forged to 70-pct reduction without serious cracking. Charge and composition have less bearing on workability than on subsequent properties. Permanent mold castings could be worked as readily as sand castings at 1,750° and 1,950° F. Plasticity improved with temperature. Small billets were also forged cold to 50-pct reduction without cracking. With equivalent nodularity, composition affects properties of wrought materials by altering matrix structure and strength. Properties vary with reduction and improve with increasing working temperature. Rolled material has high strength and anisotropy, and low ductility, particularly in the trans-verse direction. Annealing reduces strength and improves ductility, but anisotropy persists. At 70-pct reduction, impact resistance in the longitudinal direction is about twice that in the transverse. Annealing roughly doubles impact resistance. Deformation enhances damping capacity. The feasibility of die-forging and bar-rolling of ductile iron was evaluated in trial tests conducted under a Bureau contract. Although workability and ductility of ductile iron are inferior to those of steel, more advantage could be taken of ductile iron's plasticity to work rough shapes to final dimensions.

Jan 1, 1980

By A. Iannacchione

Major Hazard Risk Assessment (MHRA)1 is used to help prevent major hazards, e.g., fire, explosion, wind-blast, outbursts, spontaneous combustion, roof instability and chemical and hazardous substances, etc., from injuring miners. The structured process associated with MHRA helps to characterize the major hazards and evaluate engineering, management and work process factors that impact how a mine mitigates its highest risk. The National Institute for Occupational Safety and Health (NIOSH) studied the application of this technique to US mining conditions through a field-oriented pilot project. Risk assessment teams used in the pilot project were primarily composed of mining company personnel. Ten case studies were performed over a wide cross-section of mines. These mines were representative of the important mining commodities in the US minerals industry, i.e. coal, metal, non-metal, and aggregate. Also, the sizes of the mines ranged from small to large and were located across the country. The ten case studies demonstrate that most US mines have the capability to successfully implement an MHRA and that the MHRA methodology produced additional prevention controls and recovery measures to lessen the risk associated with a select population of major mining hazards. The basic ingredient for a successful MHRA is the desire to become more proactive in dealing with the risks associated with events that can cause multiple fatalities. A successful outcome is marked by a thorough examination of existing prevention controls and recovery measures. When pressed to consider more controls to further mitigate the risk, a well-staffed risk assessment team was able to identify additional controls. For these mining operations, it was important to add additional controls, even if they were not required by existing mining regulations, to lower the risks associated with the major hazards under consideration. If a mining operation is not willing to commit its best people to an MHRA or will not provide them with sufficient time to see the process through to its conclusion, the MHRA output may prove to be useless. Additionally, if a mining operation is not prepared to discuss its major hazards in an open and honest fashion and to present the findings of the risk assessment in a written report, the MHRA output will be unclear, and attempts to monitor or audit important controls may not be possible. A MHRA is most effective when the mining operation possesses 1) a proper understanding of its hazards, 2) experience with informal and basic-formal risk assessment techniques, 3) proper facilities, machinery and equipment, 4) suitable systems and procedures that represent industry Best Practice, 5) appropriate organizational support with adequate staff, communications and training, 6) a formal and thorough plan for emergency response, and 7) a safety risk management approach that is promoted and supported at all levels of the organization.

Jan 1, 2008

Papers presented at a U.S. Bureau of Mines (USBM) technology transfer seminar describe the causes of violent material failure in U.S. mines, measurement techniques for monitoring events that result in violent failure, and mitigation techniques for controlling failure. Specific factors contributing to violent failure are identified on the basis of geotechnical monitoring in 16 U.S. hard-rock and coal mines and on statistical analyses of 172 coal bump events. New monitoring and analysis techniques developed as tools for assessing violent failure; geotomographic methods that provide new capabilities for the study of material failure and stress changes over large areas; and seismic methods for determining source locations, calculating energy release, and determining source mechanisms are described. Fair correlations have been established among seismic parameters, elastic stresses, face support load, and violent events. USBM studies have identified the advantages using both yielding and stable pillars for coal bump control. A computer program has been developed as an aid for selecting room-and-pillar layouts. The practical aspects of implementing a destressing program is outlined for coal mines, while the importance of mine orientation and timely support installation in controlling buckling-type failure is identified for hard-rock mines.

Jan 1, 1995

By Richard L. Unger

The Bureau of Mines entered into a cooperative agreement with an eastern Kentucky coal mining company to comprehensively redesign the flow of equipment and supplies throughout its underground mines. Items were tracked from delivery to the warehouse and from surface storage areas to their final usage locations underground. Three underground mines were visited, and a great variety of tasks were videotaped for subsequent laboratory analysis. Of particular interest were tasks that required manual handling of the supplies or equipment components. Activities such as handling daily supplies (concrete blocks, rock dust, and cross- beams) and handling or lifting the continuous miner power cable were determined to be the most hazardous. Recommendations to the company included redesigned surface storage areas to facilitate the use of forklift vehicles to load the underground supply cars. Designs were also developed for different mechanical- assist devices to help in unloading the supply cars underground and to handle equipment maintenance tasks underground. Additionally, the videotapes of the underground manual handling tasks became the basis for simulating those activities in controlled laboratory conditions. This testing will contribute to developing guidelines for proper lifting techniques for low-seam coal mines.

Jan 1, 1986

By R. G. O'MEARA, Alexander M. Gow, W. T. SCHRENK

Lime is used extensively in the various industries. The National Lime Association in an excellent and recent bulletin lists 23 important in- dustries in which lime plays a vital role; and it thereby justifies the statement that "Lime is one of the most versatile and widely used reagents in the chemical and industrial world." There is, however, one application of this "universal" reagent which has not been mentioned. It is the use of lime in the flotation of ores. An appreciable percentage of the lime produc- tion is consumed by ore-dressing plants. The uses of lime throughout all the industries are more or less re- lated, but "lime" is a broad term; the varieties of lime are more mumerous than the limestones from which it is made, and its use involves a complicated technique. The interrelated application and growing importance of lime in flotation warrant this additional publication on the various "limes," with emphasis on those uses related to the function of lime in flotation. ཁྐྲ་ Lime in water treatment, cyaniding, and amalgamating will be men- tioned, after which its use in flotation will be taken up. This compendium was prepared by the Mississippi Valley Experiment Station of the United States Bureau of Mines and the Missouri School of Mines and Metallurgy, Rolla, Mo.

Apr 1, 1931

By R. W. Stahl

A survey of firefighting facilities and practices in coal mines conducted by the Bureau of Mines3/ showed such variations in equipment and apparent attitude toward fire protection that a comparison with other industry seemed advisable. Although other industry is confined generally to surface operations and the hazards probably are not as great, the same general methods of extinguishment are employed, so that the cost and protection at least should be comparable. An investigation of industry other than mines revealed a generally greater emphasis placed on fire-combating equipment, fire-brigade training, fire-fighting facility inspection, and fire-hazard elimination, as well as a greater average expenditure for fire protection.

Jan 1, 1959

These proceedings consist of an overview of the in situ mining research currently being carried out by the Bureau of Mines. The following papers emphasize two general aspects of the in situ mining method: the environment and productivity. Both areas are extremely important, particularly because in situ leach mining is a relatively new mining method from a commercial point of view. Topics covered include the restoration of ground water, the selection of lixiviants, in situ mining of commodities other than uranium, in situ mining costs, the application of resistance measurements to in situ mining, an acid leach mining case history, and the use of branched boreholes for in situ mining. A bibliography of Bureau of Mines publications on in situ mining is appended.

Jan 1, 1981

By H. C. Miller

Several agencies of the Federal Government are engaged in research and fact finding relative to petroleum and natural gas, and others are concerned with carrying out the provisions of specific laws that affect these natural resources in their broad aspects. The Bureau of Mines, however, is the only Federal agency designated by law to engage in research in oil and natures gas production, chemistry, refining, and

Jan 1, 1941

By Oliver Bowles

Accidental explosions in coal mines are due to various causes, but many of them can be directly attributed to coal dust; others that probably in no way depend on dust as a primary cause are propagated, greatly intensified, and made more disastrous by the presence of coal dust. The fact that coal dust in a bituminous mine will explode as a result of a fire-damp explosion has been generally accepted for many years, but the belief has also been held by many that coal dust is not in itself dangerous when unmixed with an explosive gas. Therefore, in past years little attention was given to dust in mines free from fire damp, and many disastrous explosions have resulted from lack of knowledge of the danger from coal dust. In the explosives gallery and experimental mine of the Bureau of Mines experiment station, Pittsburgh, Pa., it has been proved repeatedly and conclusively that coal dust will explode violently when no inflammable gas is present. PROPAGATION OF DUST EXPLOSIONS A coal-dust explosion is an extremely rapid burning or combustion of the coal particles. Their burning consists essentially of the combination of the hydrocarbons in the coal with the oxygen of the air, a process that generates heat and flame and produces hot gases and water vapor. These gases and vapors have a volume many times that of the original coal particles; thus they exert an outward motion and pressure which constitute the explosive wave. When fine particles of coal are suspended in the air, each particle is surrounded by the oxygen of the air, and thus is well placed to oxidize or burn rapidly whenever the temperature is high enough. If some particles are ignited from any cause they will fire others, and the combustion will extend from particle to particle with extreme rapidity wherever enough coal dust of sufficient purity is present.

Jan 1, 1925

By Fred W. Snow

This paper describing the mining practices at the Magma mine, Superior, Ariz., is one of a series being prepared by the Bureau of Mines on mining prac¬tices, methods, and costs in the various mining districts in the United States. At present (1929) practically all the mineral production in the Superior district is from the Magma mine of the Magma Cooper Co. The ore is mined for its copper but contains associated silver and gold. Both direct smelting ore and ore of concentrating grade are produced. The mining methods now in use at the Magma mine were adopted or developed as knowledge was gained of the physical condition of the ore bodies and the inclosing formations; the wall rock is soft and crushed and the ore is relatively hard. In general, existing methods have been adapted to fit local conditions, but some of the mining practices used were originated at this mine. Most of the ore is mined by a combination of rill stopes and pillar stopes. The pillars are extracted by underhand mining.

Jan 1, 1929

By J. H. East, D. Harrington

"INTRODUCTION Considerable interest has been shown in the prospective use of Diesel-powered haulage equipment in both coal and non-coal mines. Foreign technical magazines have devoted considerable space to discussions of the use of Diesel locomotives in European mines and some mention of it has been made in technical papers in the United States. The Bureau of Mines has extensively tested the gases produced in the exhaust of the Diesel engine under various atmospheres and conditions of use; it has established a schedule of tests for permissibility of Diesel engines for use in underground coal mines, including, gassy or dusty mines.This publication provides information as to the successful use of Diesel-powered equipment underground workings in the United States and Europe, briefly discusses the characteristics of some of the toxic gases found in the exhaust of Diesel engines, and points out that Diesel-powered equipment can be used with reasonable safety in underground minus if necessary and entirely feasible precautions are taken."

Apr 1, 1947

By Will B. Jamison

An ignition detection and suppression system was developed under the scope of this contract. The objective of this machine mounted system was to detect flames caused by frictional sparking from the cutting bits of a continuous mining machine and to suppress it with sufficient speed to prevent the development of an explosion, and to keep the flame from harming the machine operator.

Jan 1, 1976