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By H. C. Miller

[California's sensational rise to supremacy as an oil-producing State in 1923 was accompanied by a loss of 62 lives. These 62 deaths were from oil-producing accidents alone and do not include fatalities at the refineries, on tankers, or on any work not directly connected with the drilling for and the production of oil. The number of facilities for 1923 was 82 per cent greater than in 1922, the next most fatal year, with a record of 34 lives lost. The data submitted in Table 1 show that for the calendar years 1917 to 1923 inclusive, an average of 4.74 million barrels of oil were produced per Vitality in the California oil fields. On this basis, the record for 1923, hough a trifle below the average, shove up slightly better than that for 1922.]

Jan 1, 1924

By W. P. Diamond, John C. LaScola, D. M. Hyman

In 1972, the Bureau of Mines developed a direct-method test for measuring the gas content of virgin coal core samples for coal mine health and safety considerations. Since that time, approximately 1,500 coal samples from more than 250 coalbeds in 17 States have been collected for gas content determination. The gas content data, when combined with geologic and engineering studies, can be used as a basis for a preliminary estimate of mine ventilation requirements, and to determine if methane drainage in advance of mining should be considered. The data are also critical in delineating coalbed methane resources and in utilization feasibility studies. This report makes the Bureau's extensive data base of gas content data more readily available to the coal and gas industries. The data are presented in tabular form, alphabetically by coalbed name and by State. The components of the total gas content (lost, desorbed, and residual gas) are given, Location (State and county), sample depth, coalbed or formation name, and coal rank are included for geographic and geologic identification.

Jan 1, 1986

By William P. Diamonds, David C. Oyler

Stimulated vertical boreholes are an effective means of removing gas from coalbeds in advance of mining. This Bureau of Mines report examines the coal mine roof damage potential of stimulation treatments. Twenty-two Government-sponsored stimulation treatments have been mined through to determine the effects on the coalbed and roof strata. Vertical fractures in the coalbed were discernible for most treatments and horizontal fractures were present for about half of the stimulations. Sand-propped vertical fractures were usually short in lateral extent. Evidence of stimulation fluid movement could generally be traced beyond the maximum extent of sand-filled fractures when fluorescent paint was added to the treatment fluids. The maximum lateral extent for a sand-filled vertical fracture was 416 ft and a paint-coated vertical fracture extended 630 ft. Horizontal fractures were generally found within bedding planes, most commonly on top of the coalbed. The maximum lateral extent for a horizontal fracture was 265 ft at a coalbed depth of 630 ft. Horizontal fractures have been found to occur as deep as 1,145 ft. Penetration of strata overlying coalbeds was observed in nearly half of the treatments intercepted. Most of these occurrences have been interpreted to be penetrations into preexisting joints. No roof falls or adverse mining conditions were encountered that could be attributed to the stimulations.

Jan 1, 1987

Provide a machine for economically drilling probe holes in coal mines (required where there's a possibility of unmapped, abandoned workings) to check for possible water flood or gas hazards ahead of the face. Approach A lightweight air-powered drill, that mounts on a light-weight frame anchored to the face with an expandable packer, is used to drill one or more probe holes. The anchor installs quickly and will lock the drill in any desired position. How It Works The drill is portable and can be broken down to small components for ease of transportation. One man can carry these sections through restricted access routes to the working place. Components that are separable are the anchor assembly, drill frame assembly, and drill motor assembly. The drilling sequence is as follows: A 2-inch-diameter anchor hole is drilled 2 feet deep. The fixed anchor tube is rubber packer is expanded. A second anchor hole is drilled through a bushing in the anchor frame. The removable anchor tube is inserted and its rubber packer expanded. (This anchoring system withstood pulls of up to 14,000 pounds.) Next, the frame is attached to the anchor with two screw knobs, and the motor is attached to inserted in the hole and the rubber packer is expanded. A second anchor hole is drilled through a bushing in the anchor frame. The removable anchor tube is inserted and its rubber packer expanded. (This anchoring system withstood pulls of up to 14,000 pounds.) Next, the frame is attached to the anchor with two screw knobs, and the motor is attached to the frame with a single locking pin. Installing the anchor and drill takes less than 12 minutes.

Jan 1, 1981

By P. W. Jeran, S. J. Pepperney, M. C. Irani, F. F. Kopsch

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, 1980

By Noel N. Moebs

The Bureau of Mines measured surface subsidence above four small coal mine room-and-pillar sections in southwestern Pennsylvania, to obtain preliminary information on the magnitude and character of selected parameters, such as angle of draw and maximum subsidence, which are essential to the development of subsidence prediction methods. Data varied widely at the four sites; this is attributed to local geologic and mining conditions. Surface deformation at each site was of a magnitude normally associated with severe structural damage.

Jan 1, 1982

By T. H. Jeffers

Significant amounts of cobalt, a strategic and critical metal, are present in readily accessible spent copper leach solutions. For example, recovery of cobalt at two major u.S. copper operations could produce about 1,300,000 lb Co annually, about 13 pct of domestic consumption. However, techniques such as solvent extraction and precipitation have not proven cost effective in separating and recovering the cobalt from these low-grade domestic sources. The Bureau of Mines has devised a procedure using a chelating ion-exchange resin to extract cobalt from a pH 3.0 copper leach solution containing 30 mg/L Co. Cyclic tests in 4-ft-high by 1-in-diam columns gave an average cobalt extraction of 95 pct when 65 bed volumes of solu-tion were processed at a flow rate of 4 gpm/ft2 of resin area. After an impurity scrub, eluates contained, in grams per liter, 0.4 Co, 0.2 Ni, <0.001 Cu, 1.3 Fe, 2.8 Zn, and 0.008 AI. Solvent extraction procedures to remove impurities, reject nickel, and concentrate cobalt produced a cobalt sulfate solution containing 80 g/L Co, 0.05 g/L Ni, and not more than 1 mg/L Cu, Fe, Zn, or AI. Based on data from commercial electro-winning operations, this solution appears suitable for production of metallic cobalt.

Jan 1, 1985

By M. A. Reyes

This experiment investigated the effects of different machine mounted area lighting technologies on visual performance. The primary objective was to conduct a comparative evaluation of the lighting technologies based on the visual performance of thirty-six human subjects in a simulated underground mine environment. Incandescent (Incand), fluorescent (Fluor), and light-emitting diode (LED) technologies were used to create four lighting combinations. Visual performance was quantified for the detection of movement in the peripheral field of view and the identification of ground hazards. Measurements were made of the speed [response time measured in milliseconds (ms)], the accuracy (the number of targets and objects missed), and the subjective discomfort rating of the glare experienced for each lighting combination. A secondary objective explored the effects of aging on visual performance. The results indicate that lighting combinations which consisted of LED area lights significantly improved visual performance for the detection of hazards found in the peripheral field of view, as well as those found on the ground. They furthermore, indicate that age plays a significant role in visual performance.

Jan 1, 2009

By John Millhiser, Margaret Bonarek, Dennis McLaughlin

This report contains a description of the contract activities performed by ENSCO, Inc. under contract No. H0178069. The purpose of this project was to enhance the Bureau of Mine&apos;s Cableless Electronic Survey System use to aid in the drilling of long (approx. 2000 feet) boreholes in coal. This drilling is performed as part of the methane drainage program. The system that was ultimately developed was field tested and demonstrated in actual in-mine drilling activities. The significance of this system as compared to previous drill survey systems is the fact that it surveys without having to be inserted and removed for each survey point. It is so designed that it can withstand the shock and vibration experience by the drill string during drilling. This means an increased productivity is now possible in that drill operators can determine drill bit positioning in a near real-time environment.

By David R. Hanson

Experimental work performed by the Bureau of Mines in a laboratory environment has shown that the formation of failure zones within certain rock types is accompanied by the emission of significant amounts of radiofrequency (RF) electromagnetic (EM) energy. This radiation was detected using nonresonant, "electrically short," broad-band antennas. Rock types for which emission was observed include granite, quartzite, and taconite; sandstone and marble did not emit measurable radiation. Amplitude spectra of the radiation showed the energy to be concentrated between 10 and 40 kilohertz. These data indicate that emission is directional, but this has not yet been proven. In addition, amplitude of RF emission increases with increasing crack size. Since emission was observed only for brittle quartz-bearing rocks, it appears the formation of piezoelectric fields is a necessary condition for RF radiation. Plausible mechanisms for emission include rapid decay of piezoelectric fields accompanying the sudden stress release at failure and/or the acceleration of an "exoelectron plasma" through the intense local piezoelectric fields. Since emission appears to increase with the scale of failure, and since antennas do not need to be coupled directly to rock surfaces as with conventional geophones, the possibility of developing a portable system to monitor seismically active areas exists.

Jan 1, 1981

By Suresh K. Bhatt, Dennis R. Dolinar

The roof bolt system of a mine, if properly selected and installed, can allow for better roof control and reduce the potential for roof falls. Because of this potential to reduce roof falls and improve ground control conditions, the National Institute for Occupational Safety and Health (NIOSH) has an interest in the types of roof bolts that are used by the coal industry. Further, NIOSH has conducted research into how various support parameters can affect the number of roof falls that occur, including support type. Today, the five main types of roof bolts installed in U.S. coal mines are mechanical anchor bolts, point-anchor or resin-assisted mechanical anchor bolts, torque-tension bolts, combination bolts, and fully grouted resin rebar. This paper describes each support in detail. Because of the importance of resin in the functioning of the majority of bolts installed, resin grouts are also discussed. Further, trends in the types of roof bolts used are reviewed. Over the last 10 years, the significant trend has been the large reduction in the relative number of mechanical anchor bolts that are installed. These bolts have been replaced mainly by the resin-grouted rebar system. Data are also presented to show the impact of these changes in bolting on the number of roof falls.

Jan 10, 2000

By W. H. Eddy

Laboratory batch and small-scale continuous flotation tests were con-ducted by the Bureau of Mines on a mica waste tailing from Kings Mountain, N.C., to determine the feasibility of producing high-quality mica, feldspar, and glass sand. Mica was recovered by two methods; one was by flotation in an alkaline circuit, which produced a mica concentrate assaying 92.0 percent mica with a recovery of 87.l percent, and the other by flotation in an acid circuit, which produced a mica concentrate assaying 91.0 percent mica with a recovery of 79.4 percent. Continuous flotation processing yielded a feldspar concentrate assaying 1.10 percent Na20 and 13.50 percent K20, with recoveries of 66.4 and 80.6 percent, respectively. The feldspar tailing was high-quality quartz glass sand analyzing 98.6 percent Si02 and 0.02 percent Fe203.

Jan 1, 1969

By H. B. Salisbury

The Bureau of Mines conducted research to determine if low-grade California chromite ores could be beneficiated to produce products suitable for commercial use. This research is part of a Bureau goal to provide technology capable of using low-grade domestic ores to meet emergency demands of the Nation for metals and minerals and in particular those minerals, such as chromite, which are considered critical. Two ores from California were ground and treated using gravity concentration and magnetic separation techniques. An are from Auburn in central California, assaying 2.5 pct Cr203, was treated by tabling and magnetic separation to yield a nonmagnetic product containing 44.7 pct Cr203 at a recovery of 36.4 pct. Core drilling samples from the Seiad Creek area of northern California, assaying about 6 pct Cr203, were upgraded by tabling to yield a concentrate containing nearly 50 pct Cr203 with a recovery of 50 pct. Both products are suitable for metallurgical and/or chemical use.

Jan 1, 1981

By J. E. Murphy

Field freezing was used by the Bureau of Mines to effect the redistribution of the components in a cerium-12.5-atomic-percent-iron alloy. The application of the electric field caused the iron to migrate toward the anode. A field intensity of 0.04 v/cm and a current density of 240 amp/cm2 were used. The conditions that yielded the greatest redistribution of alloy components were a small thermal gradient along the specimen (from 5° C/cm to 10° C/cm) and a very slow freezing rate (0.15 cm/hr). Under these conditions it was possible to process specimens of ½ -inch diameter as compared with the capillary-size specimens used by most previous investigators.

Jan 1, 1968

By Mark I. Copeland

The Bureau of Mines discovered that silicon and nickel additions can prevent the formation of copper alloys of Sn, Sb, and As on the surface of steel during reheating to hot-working temperatures. When molten, these copper alloys cause surface hot shortness during hot working. Wrought steels were reheated isothermally and by simulated industrial practice; the resulting surfaces were metallographically evaluated. The steels contained, In weight-percent, 0.20 C, 0.45 Mn, and up to 1.00 Si, 1.00 Cu, and 0.15 Ni, and up to 0.30 Sn, Sb, or As. The larger the Cu, Sn, Sb and As content of the steels, the greater the amount of silicon necessary to prevent copper alloy formation. A content of 0.10 Ni considerably decreased the amount of silicon necessary for copper steels containing tin and antimony, but not for those containing arsenic. Theories for the beneficial effect of silicon and nickel additions are presented.

Jan 1, 1975

Improve the safety and reduce the cost of longwall entry support. Approach Replace the conventional wood cribbing with stronger, non-rotting and lower cost cribbing made of steel-fiber-reinforced (SFR) concrete. How It Works Conventional concrete can suddenly fail under excessive compression loads, but adding steel fibers to the concrete, before it is mixed with water, changes the failure mode to a gradual and controlled failure characteristic similar to wood. A system for making SFR concrete crib blocks was designed and developed (or use in constructing walls and cribs to support coal mine roofs. The SFR concrete cribbing is stronger and stiffer than wood, and avoids wood&apos;s disadvantages of: flammability, deterioration under chemical or bacteriological attack, methane generation, and relatively high cost. Use of SFR concrete also allows freer movement of miners, equipment, and ventilation air, because much less volume of SFR concrete is required than wood for a given amount of support, and because the roof-to-floor closure is greatly reduced by the stiffer supports.

Jan 1, 1981

By B. W. Madsen

As part of a program to maintain an adequate supply of minerals and metals to meet national economic and strategic needs, the Bureau of Mines conducted research to determine the diffusion coefficients for ferric ions in synthetic copper leach solutions. Determination of ferric ion diffusion coefficients in typical dump leach solutions is necessary for predicting leaching rates of copper from large-scale leaching operations and for optimizing concentrations of ferric iron in solutions to maximize leaching efficiency. Derivative chronopotentiometry, an electroanalytical technique, was used to determine ferric ion diffusion coefficients. The diffusion coefficient decreased dramatically with increasing concentration of iron in solution. An empirical model was used to relate the ferric ion diffusion coefficient to the total amount of sulfate in solution. Measuring the diffusion coefficient dependence on temperature yielded an activation energy of 5.5 kcal/mole of ferric ion. Activity coefficients of ferric ions as a function of concentration were calculated from diffusion coefficient data.

Jan 1, 1981

The object of this program was to extend the capabilities of visual paging systems both in size and function. The system developed uses the mine pager phone line for communication, monitoring, and remote control. A central station, using a mini-computer, transmits signals by phase inversion modulation of a 16,384 Hz carrier to as many as 999 remote units. The remote unit addressed returns an echo to indicate that it is functioning and, in the case of monitor units, to convey the monitor data. Magnetically latched display discs, which can be seen from both sides when posted, are used for visual paging. Lists of the addresses of posted pages, unanswered pages, and non-echoing units are prepared by the central station computer. The system was designed to be intrinsically safe and should operate for three months on a 12-volt lantern battery.

Jan 10, 1980

By W. M. Weigel

"Sand is one of the commonest materials for industrial use, not only as a building material, but in many industrial processes. The general name applies to all grades, from the comparatively impure, unsorted product used in concrete, to especially sized products of extreme chemical purity. Various definitions have been proposed, all more or less open to objection, as they fail to cover special applications. One is: ""Sand - The fine granular material naturally or artificially produced by the disintegration or crushing of rock or slag"". This does not fit the definition of sand as understood by geologists, who consider sand only as a naturally formed product. Another is: ""Sand - The fine granular material naturally produced by the disintegration of rock"". This does not take the chemical com-position into account, and for practically all uses, except in concrete and plaster products, a material composed predominantly of silica or rather quarts is implied.Sand for special purposes usually requires different methods of preparation from those where the ordinary mixture of sizes as naturally occurring are suitable. One of the classes requiring the most uniformly sized grains is sand blast sand.Sand Blast SandThe use of the sand blast has increased rapidly during the past few years. It was formerly used almost entirely in the foundry to clean and remove inequalities from rough castings. This is still the most important application, but in addition, it is now employed for the removal of paint from old surfaces, carving and engraving on stone and marble, glass cutting, cleaning or renovating the rails of stone and brick buildings that have become discolored, preparing the surface of metals for the electrolytic bath, putting the final finish to metal surfaces, and has even been proposed as a means of channeling or cutting out blocks of stone in the quarry."

Jun 1, 1924

By W. A. Cole

This report covers the preliminary phase of an investigation of clays, shales, and certain rocks in Wisconsin to determine the feasibility of processing lightweight aggregate in the State. The study was extended to include rotary-kiln testing of a limited number of shale samples, and to an appraisal of the Maquoketa shale resources in eastern Wisconsin. A total of 45 samples of clays, shales, and other argillaceous rocks of Wisconsin were tested. The lower Maquoketa shale is the only material found to date that offers possibilities as a source of material that can be processed in a rotary kiln for lightweight aggregate. Bedrock occurrences of the Maquoketa shale are found in the eastern and southwestern parts of the State. The populous southeastern region of Wisconsin presents a large potential marketing area for lightweight aggregate. For this reason special study was directed to the Maquoketa shale in the eastern district.

Jan 1, 1961