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By Eugene T. Sheridan

This report presents statistical data on individual plants in the fuel- briquet and packaged-fuel industries circularized by the Bureau of Mines, United States Department of the Interior, in its 1957 annual survey. This survey revealed that 17 briquet and 23 packaged-fuel plants were active part or throughout the year. The annual production capacity of the fuel-briquet industry was 3,088,000 net tons, a decrease of 17 percent from 1956. The decline in capacity was caused in part by the permanent retirement of 4 plants and also by the reduction in capacities of 4 other plants. The rate of production of briquet plants also decreased as the industry operated at 35.8 percent of capacity compared with 40.9 percent in 1956. Every operating plant in 1957 had an annual capacity exceeding 25,000 tons.

Jan 1, 1958

By Linda L. Chasko, Charles P. Lazzara, Ronald S. (deceased) Conti, William J. Wiehagen

Fire has long been a concern for underground mine workers. A mine fire can occur at any time and can result in a partial or total evacuation of mine personnel and the loss of lives. Fires can grow rapidly. Time is the critical element. Prompt detection, timely and accurate warnings to those potentially affected, and a proficient response by underground miners can have a tremendous impact on the social and economic consequence of a small underground fire. Fire preparedness and response have components of technology and people. These components can work synergistically to reduce the time it takes to bring the system back in balance. This report deals with the preparedness of miners to respond to underground mine fires. It is intended to aid the mining industry in understanding the various roles of emergency responders and the training techniques used to increase their skill levels. The report also presents a technology overview to assist in effective response to mine fires.

Jan 12, 2005

By Robert F. Holub

The Bureau of Mines has evaluated four working-level radiation-measurement methods and optimized them from the inherent and statistical error standpoint. Optimization with respect to various sampling and measurement times yielded no marked improvement over the existing methods. However, when appropriate approximations are made and evaluated, these two-measurement methods can be reduced to simple formulas, eliminating a need to use nomograms. These modified methods also have improved inherent error characteristics. A new method--a combination of two existing methods--with improved inherent and statistical errors has been suggested. All the pertinent equations are given, together with the computer program, so that any two-measurement method can be readily evaluated.

Jan 1, 1980

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 J. M. Stuve

Low-temperature adiabatic heat-capacity determinations were made by the Bureau of Mines in the temperature range from 5 to 300 K for the two crystalline modifications of zinc sulfide, sphalerite (ß) and wurtzite (a). The entropy at 298.15 K of sphalerite was evaluated as l4.02±0.04 cal/deg mole and wurtzite, l4.06±0.04 cal/deg mole.

Jan 1, 1974

By R. V. Ramani, R. Bhaskar

"An airborne dust cloud is an ensemble of particles of varied size, density, shape and states of aggregation. An understanding and quantifying of the dispersion and deposition of the dust generated in mines is essential to the development of measures for reducing worker exposure to dust. In coal mining, the major portion of the dust is generated during the cutting of coal using a shearer or a continuous miner.The major phenomenon affecting ambient concentration is the deposition of dust. Particle deposition may take place due to the effect of gravitational, inertial, electrostatic, and thermal forces, and mechanisms such as Brownian and eddy diffusion and inertial impaction, The three major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. The mechanisms determining particle deposition are size depend,From a review of the literature, there appears to be a knowledge gap in the understanding of the deposition phenomena in mine airways. In order to obtain a better understanding of the deposition of dust for various particle sizes, and to develop a set of data for evaluating predictive mathematical models for dust-flow in mines, a series of dust flow experiments was performed under controlled conditions in mine airways. It appears that the deposition data generally follow the theoretical behavior of dust based on the combined effect of diffusional and gravitational deposition. In this paper, the findings of the study on the deposition of dust in mine airways and its dependence on size, velocity and concentration are discussed. A set of deposition equations that could be used to determine the approximate deposition at various points in a mine airway are presented.The major factor affecting ambient dust concentration in mine airways is the deposition of dust. Particle deposition may take place due to the effect of gravitational, inertial, electrostatic, and thermal forces, and mechanisms such as Brownian diffusion, eddy diffusion and inertial impaction. The major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. Inertial impaction is significant only during changes in direction, but the change in direction of flow with resultant powerful eddies may cause increased re-entrainment of the particles, thus having a compensating effect. While the literature in aerosol sciences contain several references on deposition, most studies were done in small diameter tubes for diffusional deposition (Liu and Agarwal, 1974). The deposition data from small diameter, short tube experiments may not be applicable to studying deposition in mine airways that have large areas and extend several hundred meters. Further, the change in concentration along the length of a mine airway may significantly affect the deposition, an aspect that may not be easily determined in short tubes in laboratory experiments."

Mar 1, 1992

By W. E. Robinson

Sixty samples, selected from a 2,300-foot core of the Green River Formation in Colorado, were studied to ascertain differences in the structure of the organic material present in the oil shale samples. Emphasis was placed upon relating differences in the aromatic content of the insoluble kerogen and the alkane content of the extractable material obtained from the selected samples. The methods used in determining these differences consisted of fractionation of the soluble material, carbon and hydrogen analysis, volatile material determination, carbon residue determination, oxidation rate determination, and infrared analysis. In general, it was concluded that the organic material in this core does vary in chemical structure and that same of these variations resulted from factors related to depth of burial. Other observed changes in structure of the organic material were not depth-dependent and resulted from other factors such as source material variations, biological alterations, or ecological differences.

Jan 1, 1971

By David E. Siskind

The Bureau of Mines performed a comparative study of nine sites at eight surface coal mines to determine if the presence of near-surface underground abandoned workings resulted in the generation of adverse long-duration, low-frequency blast vibrations. Six of the nine sites had underlying workings, and two had thick layers of low-velocity unconsolidated surface material. Extended seismic arrays were used to identify the vibration characteristics within a few tens of feet of the blasts and also as modified by the propagating media at distances over 1 mile. Production blasts and specially fired single-charge blasts allowed the determination of natural ground frequency and the influence of initiation delay timing. Vibration amplitudes from the production blasts at all sites exceeded historical norms, particularly at the greater distances. This contrasts with the near-normal results from single-charge blasts. Apparently, between-hole time delays were insufficient to separate vibrations from adjacent charges for the low-frequency waves present. Single-charge tests showed that the propagating media produced low-frequency, ground-roIl-type surface waves at nearly all sites. Large blasts at such sites could produce an unacceptable risk of vibration-induced cracks in nearby structures.

Jan 1, 1989

By M. K. Larson, J. P. Dunford, E. G. Zahl, T. M. Brady

Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health, Spokane, WA, have collaborated with three Western longwall coal mines in an on going effort to develop technologies that will aid in providing safe and stable working areas. The goal of the research described here is to develop a stress monitoring system that will provide immediate information to mine managers for making daily safety decisions as areas of poor ground are mined through. Initial work has focused on answering preliminary questions regarding the reliability and use of stress change patterns. Research is concentrated on monitoring horizontal stress because horizontal stress is transmitted over long distances through stiff strata, thus allowing an extended length of entry to be monitored. This paper presents an explanation of the concept, key results from field tests at two mine sites, and a proposed process for implementing a monitoring system. System design layouts, instrument use, data collection and interpretation methods, and processes to present findings to mine staff are described. Additional validation and correlation with actual failure mechanisms are required before this approach can be recommended at ongoing operations. However, initial results indicate that this approach shows promise in mines prone to bumps and roof falls associated with large stress changes. In particular, analyses of measured changes in horizontal stresses appear useful.

By Lisa Steiner, Robin Burgess-Limerick

Working with or near underground coal mining equipment is hazardous because of the multiple sources of energy and adverse environmental conditions. Of the 4169 injuries reported to Coal Services during the three years to June 2005,447 were associated with continuous miners, 232 with LHD (load-haul- dump) vehicles, 140 with shuttle cars, and 140 with personnel transport - a total of 959, or 23% of all injuries reported during the period. An analysis of the injury narratives accompanying these injury claims highlights a number of opportunities for controlling injury risks. Using the frequency of reported injuries for the prioritisation of risk control strategies has limitations because of the tendency to underestimate the importance of relatively uncommon but potentially high consequence events. Injury reports also underestimate the contribution of risk factors such as whole body vibration, which have a long-term cumulative contribution to an elevated risk of injury. However, taking these limitations into consideration, the results of the injury narrative analysis suggests the following hazards as the highest priority for elimination or control: • handling continuous miner cable • strain while bolting • slipping off continuous miner platform • inadvertent or incorrect operation of bolting controls, and operation of controls while a person is in a position of danger • hitting potholes or other roadway abnormality • collisions while driving underground vehicles

By A. J. Strazisar

The Bureau of Mines conducted a laboratory investigation to study the effectiveness of low-pressure steam and water spray in suppressing respirable dust at the tips of a saw-type cutting wheel. Suppression efficiencies were found to be proportional to the amount of the water or steam applied at the cutter tips. For equivalent water output rates, a maximum efficiency of approximately 80 percent was reached for both steam and water spray. Results from the steam and water spray tests showed an increase in suppression efficiency with an increase in particle size of 1 to 8 micrometers. The data indicate no advantages for using steam as a dust suppressant.

Jan 1, 1972

By J. W. Walkiewicz

One of the objectives of the Bureau of Mines is to develop substitution technology for scarce materials. In accordance with this goal, alloys containing lanthanum, cobalt, copper, and magnesium were investigated for fabrication of rare-earth-cobalt (RE-Co) permanent magnets. A complete substitution of lanthanum for samarium and a partial substitution of copper for cobalt was accomplished. Magnets of La-Co and La-Co-Cu-Mg alloys were fabricated by powder metallurgy techniques and evaluated. A maximum intrinsic coercivity of 23.2 kOe was obtained with a La-Co-Cu-Mg alloy. In comparison, maximum values of 9.3 kOe and 11.6 kOe were obtained with La-Co and La-Co-Cu alloys, respectively. The substitution of copper and magnesium for part of the cobalt resulted in a large increase of intrinsic coercivity, similar to the results of Bureau research with mischmetal-Co-Cu-Mg alloys. Unlike the mischmetal-Co-Cu-Mg magnets, the La-Co-Cu-Mg magnets showed signs of physical deterioration on exposure to air. The effects of fabrication parameters on the magnetic properties of the La-Co-Cu-Mg alloys were also determined.

Jan 1, 1982

By Fun-Den Wang

A two-dimensional plane strain analysis by the stiffness matrix method was used to analyze two basic pit slope configurations. The magnitudes and the directions of stresses are given for a V-shape and for a flat-bottom pit with the slope angle varying from 30° to 90° at 10° intervals, Stress effects due to irregular pit configuration or to in-situ forces are discussed. Equations of similitude for gravity loading are given. Expressions are also given for the stresses at the toe as a function of slope angle. Procedures are given for finding the stresses in any geometrically similar pit slope of different dimensions and material properties from the stresses and equations presented in this report. Numerical results show that the V-shape pit slopes have lower stresses than the flat-bottom pit slopes; hence, they are inferred to be more stable.

Jan 1, 1970

By D. E. Kirby

In the preparation of beryllium-copper alloys by fused-salt electrolysis, beryllium was electrowon from beryllium oxide dissolved in fluoride electrolytes and deposited on copper cathodes. At 880° to 1,030° C, deposition was on solid cathodes. Beryllium deposited on the copper, forming a liquid alloy that dripped from the cathode. Dripping alloys containing 3 to 4 weight-percent beryllium were produced with as high as 90 percent cathode current efficiency, by electrolysis at 910°.C. To prepare alloys of higher beryllium content, attempts were made at depositing beryllium on liquid copper cathodes. These efforts were generally unsuccessful, although alloys containing as much as 12 percent beryllium were prepared by this method. At temperatures of 1,100° to 1,300° C, requisite to maintaining beryllium-copper compositions as liquids, the beryllium reacted with cell structures.

Jan 1, 1972

By Joan C. Biordi

The Bureau of Mines used molecular beam-mass spectrometry to determine the microstructure of a 10.1% CH4-2l.2% 02-67.6% Ar-1.1% CF3Br inhibited flame and its uninhibited analog, both stabilized at 32 torr on a cooled flat-flame burner. Composition profiles of atomic, radical, and stable species and temperature profiles for both flames were obtained and compared. Kinetic analyses of the profiles yielded values for the rate coefficients of several elementary methane flame reactions and information on the reactions of formation and decay of the observed halocarbon species. CF3Br is judged to decay by thermal decomposition as well as by abstraction reactions, and the fluorocarbon chemistry occurring in the inhibited flame is due primarily to CF2 radical reactions. Rate coefficients and mechanisms for reactions of the inhibitor-related species are given.

Jan 1, 1978

By Kenneth M. Earl

In its investigation of deposits of strategic minerals, the Bureau of Mines lid some development drilling at the Milan deposit in an endeavor to find an additional source of supply of copper. The deposit, which is in Coos County, northern New Hampshire, is about 8 miles northwest of Berlin. It was discovered in the seventies and was worked steadily until 1886, yielding a monthly production of 2,600 tons of ore. Lessees opened the mine again in 1695 and mined 1,500 tons. The Milan Mining & Milling Co. acquired the property in 1907 and made regular shipments of ore and concentrates until 1910. From 1911 until 1938, the tract was held by a local resident for timber land, Ventures, Limited, a mining concern with headquarters at 25 King Street, West, Toronto, Canada, acquired the property in 1938. No production has been recorded since 1910. To cut the vein below the old mine workings and to search for extensions to the northeast and southwest, the Bureau of Mines diamond-drilled eight holes for an aggregate of 3,596.2 feet.

Jan 1, 1950

By D. R. Douslin

This report describes an inclined-piston pressure gage that operates from a zero-pressure datum level. The gage is adaptable to accurate vapor-pressure measurements in the low and intermediate pressure range, 0.01 to 40 mm (mercury). Residual friction in the oil-lubricated piston-cylinder combination is eliminated by a unique oscillatory method that is free of end thrust on the piston and allows the full sensitivity of the gage to be realized. The axial component of the weight-to-area ratio of the piston is determined by measuring the angle of inclination with a goniometer that can be read to 1 sec. Accuracy of the gage proper is estimated to range from 0.001 to 0.012 mm from lower to upper pressure limits. Its highest practical sensitivity is about 0.0005 mm. As a test, the vapor pressures of ice and water were measured in the range -30° to +20° C.

Jan 1, 1963

By Charles Anema

The Mancarried and Helicopter Receivers were developed under the contract I for trapped miner location. This program was a five phase program with 15 mancarried and 5 helicopter production receivers delivered under Phase IV and equipment documentation required under Phase V.

Jan 11, 1976

By L. G. Marsh

The manufacture of lubricating oils from wax-bearing crude petroleums involves the removal and recovery of the paraffin wax contained in the lubricating distillates. During this process several intermediate products are formed, among them the mixture of waxes and oils known to the refiners as "foots oil." Because of its complex character, foots oil is little understood, and therefore methods of handling it in refineries are often inefficient. The Bureau of Mines is studying the manufacture of lubricating oils, and during the work has investigated the redistillation of foots oil. This report gives in brief the results of the investigation, and recommendations based upon it.

Jan 1, 1926

By Daryl E. Radcliffe

This report describes an instrument system developed by the Bureau of Mines to continuously monitor and record changes in roof displacement during underground mining activity. The instrument consists of a single-wire extensometer coupled to a mechanical-drive chart recorder mounted in an aluminum frame installed in the roof. The unit is small and simple to install and meets safety requirements for use in underground coal mines.

Jan 1, 1977