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By W. A. Selvig

The experiments described herein were made at the request of Committee D-5, on Coal and Coke, American is n Society for Testing Materials, in order to obtain data as to the probable contamination of laboratory samples of coke Then pulverized to pass a No. 63 sieve of tine U. S. Standard Sieve Series2 by methods other than by ball-mills or hard-steel diamond mortars, which methods are specified-in the standard methods of that Society.3 After pulverizing, representative samples were analyzed by the Bureau of Mines at Pittsburgh for ash content to detect any contamination of the samples by the pulverizing apparatus. Preparation of Core Samples for Tests. Two samples of 48-hour beehive coke (Continental and Leisenring) made from Pittsburgh coal were selected for the tests. These cokes were crushed approximately to No. 10 sieve size, by first passing through a jaw crusher and then through a, roll crusher. The crushed coke was then carefully mixed and riffled into portions of about 800 grams each, and sent to three cooperating laboratories for grinding, through a No. 60 sieve. Size tests on these samples shoved the fineness to be as follows: [ ]

Jan 1, 1925

By K. K. Kershner

Important contributions can be made to conservation of natural resources by recovering mineral values from primary and secondary metallurgical slimes and flue dusts. This applies particularly to ultrafine mineral particles that escape recovery by conventional mineral dressing. In the interest of economy and conservation the Bureau of Mines is investigating fundamental properties of ultrafine mineral values in slimes as a means of developing new or improved methods of mineral recovery. The work described in this progress report was carried on in the Bureau's laboratories at Rolla, Mo., from 1951 to 1953. The mineral material used as a subject for study was tin-ore slimes. DESCRIPTION OF TIN SLIMES The tin slimes consist principally of quartz, with appreciable quantities of tourmaline and sericite mica and small amounts of cassiterite, pyrite, hematite, and arsenopyrite. The tin content is approximately 0.5 percent.

Jan 1, 1954

By Kenneth H. Johnston

Information and data necessary for research on improving methods of oil recovery from low-permeability reservoirs and for comparison and evaluation of performance of such reservoirs with those producing from more permeable sands were obtained. Core analyses, well logs, production tests, well stimulation techniques, primary and secondary production records, and data on two water-flood projects were examined for wells producing from the Bartlesville sand, West Avant field, Osage County, Okla. Overall recovery from the study area was generally poor with only 9.0 percent of the pore volume recovered to January 1, 1968. Larger fracture treatments (8,000 to 12,000 gal) could have resulted in an increase in primary oil recovery. Secondary recovery by water-flooding accounted for only 1.9 percent of the pore volume because of the inability to control the large volume of injection fluid that escaped from the flood patterns and the excessive volumes of water produced with the oil. Future waterflood development in other low-permeability reservoirs should include the drilling of new input wells, use of injectivity surveys to locate possible natural fracture systems, or zones of high permeability, and control of injection fluids by altering flood patterns and/or plugging of the more permeable zones.

Jan 1, 1968

By J. E. Zeilinger

The technical feasibility of using energy from explosive ignitions of coal dust to pump water was .demonstrated in an exploratory investigation. Ignition of small amounts of pulverized coal that were dispersed in air over columns of water pumped up to 5.3 gallons of water per cycle when operated against a head of 30.75 feet. Water displacement was accomplished by either manual or automatic operation through a single cycle, and by automatic operation through a continuous series of cycles of I-minute duration. Operating through single cycles, slurries containing up to 3 pounds of coal and 4.6 gallons of water were also pumped. Possible uses of an efficient coal-fired pump would include pumping water for irrigation purposes, removing water from mines, transporting coal from mines in the form of a slurry, and pumping water to elevated reservoirs at electric powerplants so that it could be used to generate electricity during peak periods of demand.

Jan 1, 1966

By Howard C. Turnage, Dana T. Updyke

An evaluation was made of one of several improved underground communication systems sponsored by the U.S. Bureau of Mines. The system evaluated was installed in a typical metal/non-metal room and pillar mine and utilized UHF repeaters connected to a unique distributed antenna and passive reflector system which provided mine-wide communications. A microprocessor controlled data collection system was assembled and installed for the evaluation. Data consisting principally of times and durations of messages and identities of the originating transceivers was collected between February and August of 1982 (6 mos.). Analysis of the data shows that the principal benefits are reduction in time required for unscheduled maintenance and repair, enhancement of safety, and better coordination of production activities. A cost benefit analysis shows a net benefit over cost, although it is also concluded that the capacity of the system is greater than can be justified by current activity in the mine.

Jan 2, 1983

By Jon C. Volkwein

The canopy-air curtain was originally developed by the Bureau of Mines to surround the operator of a continuous mining machine with a zone of clean air. This report describes the application and testing of a canopy-air curtain on a gathering-arm loader, as well as some of the problems associated with providing a zone of clean air to a standing, semimobile operator. The area of air-curtain coverage and effects of air velocity are discussed. In its present form, the canopy-air curtain provides a 50 percent reduction in respirable dust to the operator.

Jan 1, 1981

By Frank E. Cash

Large quantities of explosives are consumed in the underground mining of ores in the Lake Superior district. Because of the recognized danger of accidentally releasing the potential highly destructive forces contained, the safes possible procedure in the transportation, storage, and use of explosives is necessary. Underground magazines recently constructed in the district give evidence of the earnest desire of the mine operators to incorporate all possible safe-guards in the storage of explosives, including a careful choice of location and arrangement in the plan of the magazine.

Jan 1, 1946

By M. C. Irani

The Bureau of Mines has designed and put into operation a fail-safe control system for use in underground coal mines equipped with methane drainage pipelines. This control system can detect certain unsafe conditions and respond by automatically shutting off the flow of methane from the degasification borehole to the drainage pipeline. Methane flow is shut off when the methane content in the return airways reaches a predetermined level (typically 1.5 pct), when the methane drainage pipeline is ruptured by roof fall, or when there is an electric power failure. The fail-safe control system was designed using commercially available components and a methane analyzer system previously developed by the Bureau. The fail-safe system consists of a unit that combines a shutoff valve and pneumatic valve actuator, and electronic and mechanical equipment designed to detect hazards and effect shutdown. The fail-safe control system was designed to meet regulatory requirements issued by the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, and State regulatory bodies for the safe operation of underground methane pipelines used for mine degasification. MSHA has inspected and tested this system and permitted its use in two mines. The Bureau installed the fail-safe system in two working coal mines, where successful performance has been demonstrated.

Jan 1, 1979

By J. A. Lamonica

The Bureau of Mines studied two types of approved coal mine dust personal samplers to determine the effect of decreasing the amplitude of airflow velocity fluctuations on cyclone performance. Results indicate that more dust is collected when pulsation free flow is used. Velocity fluctuations were reduced by means of a pulsation damper; damper efficiency of about 85 percent was needed to reduce the fluctuations to an acceptable level. The data were obtained employing both pulsating and non-pulsating flow. A comparison was made of (1) the masses of respirable coal dust as determined by weighing and of (2) the particle size distributions as determined by an electronic counter. An empirical relationship is given between the ratio of masses collected using pulsating and nonpulsating flow (M') and the ratio of the maximum air velocity to the minimum air velocity (V') as measured in the cyclone entrance channel.

Jan 1, 1972

By R. R. Brandenthaler

A series of open-flow tests was conducted in the Chickasha gas field, Grady County, Oklahoma, during June, 1927, under the direction of the U. S. Bureau of Mines and at the request of the Oklahoma Corporation Commission. The purpose of these teats was to determine whether or not any differences existed in the open-flow volume of a gas well when taken through well-head nipples of different diameters, and further, to establish if possible a relationship between open-flow volumes taken through well-head nipples of various diameters. The open flow of a well is the volume or quantity of gas, measured under standard conditions, that a well will produce when open to the atmosphere. There are several methods used for determining the open flow of wells; some of the methods are more suitable under certain conditions than others. The Pitot tube method is the simplest, is applicable to almost any condition, and is the one most commonly used. In the tests described in this paper no attempt was made to compare the Pitot tube method with the minute pressure measurement method or the orifice measurement method.5

Jan 1, 1928

By Thomas P. Mucho, William D. Monaghan, John Wood, Michael A. Trevits

We have tested the ability of ground penetrating radar (GPR) to resolve adjacent mine workings. The work was conducted at two National Institute for Occupational Safety and Health locations – an underground coal mine and an underground limestone mine. The objective of our work was to determine if GPR signals could be received from distant mine workings. The GPR system was calibrated on underground mine pillars of known dimensions using a variety of antennas. The system was then tested at several underground locations in an effort to detect an adjacent drift entry; and an adjacent abandoned coal mine. As a means of verification, an in-seam horizontal hole was drilled from the active coal mine to the abandoned mine to confirm the presence and location of the abandoned mine workings. Our results show that in the case of the limestone mine the maximum depth of penetration where the mine workings could be resolved was 85 ft; and in the case of the coal mine the abandoned mine workings could be resolved at a depth of 205 ft. We conclude that it may be possible to utilize GPR for initial underground mine studies followed by directional drilling to accurately delineate the extent and position of adjacent abandoned mine workings.

By W. A. Cole

The sulfur shortage that existed during the Korean conflict stimulated interest in coal measures as possible sources of sulfur. One of the areas brought to the attention of the Bureau of Mines was in Marion County, Iowa, where comparatively high-sulfur coals and other marcasite-bearing strata were known to occur. A Bureau of Mines engineer inspected the marcasite occurrence on December 4, 1954; this prompted further work on the Iowa coals and associated formations as a source of iron sulfides. An investigation of the Iowa high-sulfur coals was undertaken including core drilling, field reconnaissance, and compilation of data pertinent to consideration of the following: 1. Upgrading Iowa coal by mechanical cleaning and the feasibility of recovering sulfur from coal brasses. 2. Possibility of processing the high-sulfur coals by adaptation of methods employed in processing industrial gases to produce sulfur and sulfur products. 3. Possibility of finding concentrations of iron sulfides in associated rock formations in sufficient quantity for economical recovery.

Jan 1, 1957

By John P. Coughlin

Software techniques developed by the Bureau of Mines Denver Research Center for real-time microseismic data analysis are presented. These techniques focus on the simple acquisition of P-wave arrival times and their use in event location. The paper discusses in detail software techniques to separate microseismic events from mining noise such as drilling and from very large events such as rock bursts. Incorporation of these techniques has enhanced the reliability and accuracy of computer-based monitoring of microseismic activity in ongoing research by the Bureau.

Jan 1, 1982

By Andrew B. Cecala

The Bureau of Mines conducted laboratory and in-mine tests on the Racal airstream helmet (Model #AR21) to evaluate its protection efficiency. Laboratory tests indicated that as ambient air velocity increased, the protection offered by the helmet decreased. In tests conducted at several coal mine long-wall sections with face velocities under 400 fpm, the helmet was 84 pct effective at reducing respirable dust in the miner's breathing zone. However, at a high-velocity section, 1,200 fpm, the efficiency of the helmet was significantly reduced, confirming our laboratory results.

Jan 1, 1981

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 John J. Sammarco

As part of a project to automate coal extraction, computer control of a continuous mining machine test bed has been developed and tested by the Bureau of Mines. A computer system and control software were developed for accurate positioning of the conveyor elevation and swing, stabilizer jack, gathering head, and shear elevation. Tramming actions are also controlled by the computer. The computer system was designed to access data from sensors installed on a continuous miner and to interface with the existing control circuits of the miner. Testing in free space was used to characterize the operation of the machine. From this information, control algorithms were written and stored in the computer. The ability to control each function of the continuous miner with a high degree of accuracy and stability was successfully demonstrated in a series of tests in free space and in mining a block of simulated coal. In the mining of simulated coal, the cutting drum was instructed to position the shearer at the top of the block and shear down to the bottom under closed loop control. The cutting drum came within 0.27 in of the top and within 0.49 in of the bottom of the block for this shearing test.

Jan 1, 1988

By Walter W. Fisher

A kinetic investigation of copper cementation in a revolving drum was undertaken by the Bureau of Mines to explore the effects of a porous copper deposit attached to the iron surface and a fluidized slurry of copper particles surrounding the iron precipitant. The rate of cementation was found to be significantly enhanced by the increased cathodic areas provided by a porous copper deposit or the presence of a fluidized bed of copper particles contacting the iron precipitant. The cementation rate was found to be retarded by increased ionic strength, low pH, and the presence of oxygen. The cementation reaction was first order with respect to precipitant surface area. Copper cementation on iron is visualized to occur by two basic mechanisms. Precipitation may occur through a series of shorted electrochemical cells, whereby cupric ion precipitates on a growing cathodic copper deposit, or, deposition may occur via a fluidized cathode of copper particles contacting the ion precipitant.

Jan 1, 1976

By C. J. Thompson

In the course of the work currently conducted by the Bureau of Mines in cooperation with the American Petroleum Institute Research Project 48 on identifying sulfur compounds in petroleum, a micromethod was developed (12)5 for catalytically removing the sulfur atom from sulfur compounds. The product is the residual portion of the molecule; the structure otherwise was unaltered except for hydrogenation of any unsaturated bonds that were present in the original compound. Positive identification of sulfur compounds isolated from crude oils is a difficult problem. Direct comparison of properties of the unknown with those of reference compounds is often impossible because of the limited number of reference sulfur compounds available. However, a relatively large number of pure hydrocarbons is available, and the conversion of the sulfur compound to a hydrocarbon enhances the possibility of identification. The technique also can be used to prepare microquantities of scarce hydrocarbons by hydrogenating compounds that are readily available.

Jan 1, 1962

By E. J. Gleim

The construction of explosion-proof electric mine equipment for operation in gassy coal mines of the United States was begun as early as 1903. In 1.906, similar equipment with special protective devices was built for export. An investigation of explosion-proof motors was conducted by the United States Bureau of Mines during 1910 and 1911. In other words, this was among the first efforts of the Bureau directed toward the saving of life and property subsequent to its establishment by act of Congress in 1910. In these early motors, those with special devices for relief of explosion pressures predominated. At that time it was generally considered that, by providing for pressure relief, the enclosures could be made lighter in weight because of the lower explosion pressures developed within.

Jan 1, 1954

By Jamie Girard Dwyer, Edward McHugh, Stanley Miller, Jeffrey Whyatt

This user's guide covers the operation of a suite of three computer programs-Bplane, Bstepp, and Bwedge. These programs can be used to evaluate the potential for plane shear, step-path, and wedge failures along the crest of a slope bench. Such failures reduce the width of a catch bench and may compromise the bench's ability to catch rolling or sliding material before it reaches miners working below. The Bplane and Bwedge programs address sliding of blocks defined by continuous planar joints. The Bstepp program examines sliding of blocks defined by more complex failure surfaces that include steeply dipping cross joints and may even include breaks across small bridges of intact rock. The programs are applicable to jointed rock masses where the joints are small relative to the overall slope and form a number of sets with uniform statistical characteristics within a slope sector. The theoretical basis, application, and operation of these programs are described.

Jan 3, 2007