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By E. W. Dean

The Bureau of Mines is engaged in the work of obtaining data regarding the physical and chemical properties of typical crude oils from the various producing fields of the, United" States. Preliminary reports have been published that cover the eastern fields* and the' Rocky Mountain districts.** Since the appearance of these, reports: it has been suggested that certain additional data. I regarding the samples would be of practical value. It was believed that a knowledge of the viscosity of crude oil was desirable, particularly in connection with the design and operation of pipe lines. In accordance with this suggestion, the authors have made viscosity tests upon as many of the samples of the two series as wore still available for examination. Determinations were made at temperatures of 70° and 100°F., and in addition the oils were Subjected to the A. S. T M, pour-test*** to as certain the lowest temperatures at which they remain in a fluid condition.

Jan 1, 1921

Provide a method for obtaining in situ measurements of coal cutting forces which are needed for mining machine design. Approach A portable in-seam testing device is carried to the face of an underground coal mine heading to measure the cut-ting force encountered by a continuous miner pick directly at its maximum depth of cut. How It Works The tester frame is attached directly to the coal surface with four one inch diameter threaded studs resin-bolted into 1-1/4 inch diameter holes which are drilled 30 inches deep. Spherical nuts and washers compensate for misalignment between the bolts bearing plate, and traverse beams. Spacers can be placed over the studs to assure that the traverse beams remain in the same plane. Cutting forces are applied by a hydraulic cylinder that moves the pick of the tester through a twin-chain arrangement which gives a 20-inch cutting stroke with

Jan 1, 1982

To restore ventilation and prevent the accumulation of explosive or toxic gases by quickly installing substitutes for stoppings blown down by an explosion. Approach Temporarily replace blown down stoppings with a parachute-shaped brattice which can be erected in minutes. How It Works The self-sealing brattice is secured to the roof, ribs and floor by anchoring its nylon edge strip at several points using extensible poles, shads, or available projections such as roof bolts. The air pressure in the entry pops open the chute of lightweight sailcloth, forcing it tightly against floor, roof and rib. See Figure 1. This emergency brattice has been tested at two locations in the Bureau's Experimental Mine at Bruceton, Pennsylvania. In a test last December, one MESA inspector wearing full rescue apparel (including self contained breathing apparatus) installed a self sealing brattice in an entry at the Bruceton Mine. Although he did not have any previous experience with the device, he easily erected it in slightly less than 10 minutes, using two extensible supports (pogo sticks). Research to improve and refine the self-sealing brattice is continuing.

Jan 1, 1977

By Phyllip Worley, Frank E. Chase, Christopher Mark

The Harris No. 1 Mine, located in Boone County, WV, has been longwalling the Eagle Coalbed for over 30 years. Harris has experienced numerous interactions associated with the extensive room-and-pillar and longwall mining operations which have been conducted in the overlying No. 2 Gas Coalbed. The problems have included roof falls, excessive rib sloughage, and gateroad and bleeder entry closure. A detailed evaluation of the multiple seam experiences at Harris No. 1 Mine was conducted as part of the National Institute for Occupational Safety and Health (NIOSH) nation-wide multiple seam mining case history data base. One observation from the Harris gateroad case histories was that smaller, critically loaded, upper seam pillars seemed to cause more severe ground conditions than did wider pillars. The LaModel program was used to investigate this supposition, and the results confirmed that “critical” sized pillars do transmit the highest amounts of stress to adjacent seams. In addition, the data suggest that the probability of a major multiple seam mining interaction increases when the depth of cover is 1,000 ft or greater and when the Eagle seam pillars have a Analysis of Longwall Pillar stability factor less than 1.50.

Develop a down-hole replaceable diamond core bit that will reduce overall drilling costs and increase total available drilling time per hole. Approach A one-piece diamond core drill bit of unique geometric shape has been designed, fabricated and field tested. The bit can be withdrawn (or replaced) from the bottom of the well-bore without removing the drill rods from the hole, saving a significant amount of non-productive drilling time. How It Works The replaceable bit system consists of two basic subsystems: the removable core bit, and the equipment necessary to replace the wornout bit without pulling the drill rods out of the hole. The geometric configuration of the bit is that of a one-piece diamond studded cutting element created by "slicing off" two parallel sides of a conventional diamond cone bit. This geometric configuration, along with some minor modifications to the outer core barrel, allows the bit to be rotated in two planes and, with the retraction-insertion tools, raised or lowered through the interior of the drill rods using a conventional wire-line system. For example, to retrieve the bit, a retraction tool is lowered through the drill rods using a conventional wire-line system and at the hole bottom, the tool automatically orients itself within the outer core barrel.

Jan 1, 1981

Develop an alternative to water bath exhaust conditioners (water scrubbers) for permissible diesel equipment used in gassy mines. Background Water scrubbers are a safety device used on diesel-powered vehicles in gassy mines. Exhaust from the engine passes through the scrubber, where it is cooled, and any flames or sparks present in the exhaust are extinguished. This prevents the ignition of combustible mine dust or methane that may be present. Unfortunately, water scrubbers consume large amounts of water and require frequent maintenance. Approach Methods that do not require water replenishment and frequent maintenance were investigated. The dry exhaust conditioning system was selected for investigation because no water is consumed and existing heat exchanger technology can be adapted to underground mine vehicles. In accordance with U.S. Mine Safety and Health Administration (MSHA) requirements, the system was designed to cool exhaust and trap flames and sparks. The U.S. Bureau of Mines (USBM) developed and evaluated a system for large engines and evaluated a second system for smaller engines. Both systems were evaluated on an engine test bed; if warranted, the system was then tested underground.

Jan 1, 1993

By D. Cummins

This Information Circular presents a brief history of the lead-acid battery and describes ways to prevent serious injury from battery explosions when servicing and charging lead-acid batteries, particularly in the surface mining industry. The Mining Safety and Health Administration (MSHA), U.S. Consumer Product Safety Commission, battery manufacturers, and the mining industry have all contributed information as well as recommendations for injury-free handling for this report.

Jan 1, 1980

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 Donald W. Fausett

This Bureau of Mines publication presents a system of thermal decompositions providing an adequate description of the mechanism of oil shale pyrolysis. Specific rate constants for systems of thermal decompositions studied are estimated via a least-squares procedure. The estimates thus obtained provide a mathematical model of the corresponding thermal decomposition system. A model that generates a good fit to published Bureau of Mines experimental data, in comparison with other models studied, is based on a thermal decomposition system consisting of two first-order reactions and three second-order reactions. Values computed for the specific rate constants corresponding to this system are shown to exhibit a temperature dependence that is in good agreement with the Arrhenius equation.

Jan 1, 1974

By D. E. Traut

A fluidized, countercurrent ion-exchange system was developed, operated, and evaluated by the Bureau of Mines in support of its objective to help assure an adequate uranium supply for future national needs. The system consisted of integrated multiple-compartment absorption and elution columns in which the solution flows are continuous, except for short periods when resin increments are withdrawn. The exchange of uranyl sulfate between a simulated acid-leach-uranium solution and a strong-base, ion-exchange resin was studied, together with subsequent elution using an acidified sodium chloride solution. The effects of the number of compartments, compartment height, amount of resin withdrawal, solution flow rate, and column diameter were investigated. Also examined were the kinetic and equilibrium relationships for the absorption and elution steps. The experimental data indicate a strong interdependence between variables. Solution retention time appears to be a major limiting variable in the absorption process, while resin residence time is the determining factor in the elution process. The columns system was efficient over a range of conditions, but close control was needed for optimum operation.

Jan 1, 1978

Objective To develop and evaluate the effectiveness of safety training tools specific to underground metal/nonmetal mining. Background In a series of stakeholder meetings held in the western United States beginning in 1998, participants identified a critical lack of appropriate training materials applicable to metal/nonmetal mining. Participants in the meetings provided many insights into what types of training materials are most effective in dealing with both experienced and inexperienced miners. Most important was that the materials should be realistic and interesting and that some way should be found to capture the wisdom and expertise of older miners before they retired. In response, training videos that focus on safe practices during the mining cycle are being produced. Two videos one on handling explosives underground and one on identifying roof hazards and proper scaling techniques were completed during1999, and a third video is now available. This video, entitled “Ground Support...It’s Important, or Miner Mike Saves the Day,” presents information on why ground supports work and how to install them properly. Approach The new video, “Ground Support…It’s Important,” presents a scenario in which two young miners make a bad decision to leave some supports out in order to catch up in their mining cycle. An expert miner, “Miner Mike,” sees this potentially disastrous situation and educates the young miners about what could happen if they continued to leave supports out. He introduces the young miners to several expert miners, who explain how to install different types of supports correctly, as well as share what experience has taught them over the years. How It Works All footage was taken in operating, underground mines, using14 experts to provide the teaching. Because of the wide variety of supports used underground, it was necessary to focus on those types more common to hard-rock mining. While more complex support systems, such as shotcrete and cable bolts, are mentioned, detailed material is not included. In the course of educating young miners Jeff and Jason, Miner Mike provides information on— •Why supports are necessary in underground mines. •The main types of supports commonly used in underground hard-rock mines. •How supports work. •How holes for bolts are drilled correctly using jacklegs, drill jumbos, and bolting jumbos.• How wire mesh, wire panels, metal mats, and different types of bolts, including mechanical bolts, friction bolts, grouted bolts, and cable bolts, are installed properly. •How to recognize that supports have failed and what to do about it.

Jun 1, 2000

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

By John L. Reuss

A laboratory study was conducted by the Bureau of Mines to investigate the technical feasibility of decomposing hydrous magnesium chlorides by using a steam pyrohydrolysis technique. This procedure consisted of injecting steam into the atmosphere of a decomposition furnace containing samples of hydrous magnesium chloride and determining the rate of hydrolysis by measuring the rate of chloride evolution. The variables investigated were temperature, amount of water vapor in the decomposition atmosphere, and hydration stage of magnesium chloride. The application of steam was shown to accelerate both the rate and completeness of magnesium chloride decomposition reactions. For example, when magnesium chloride hexahydrate is exposed to a furnace temperature of 600' C in an air atmosphere for 20 minutes, the decomposition is 37 percent. Under identical conditions in a steam atmosphere, the decomposition is in excess of 70 percent. The magnesium oxide produced by the steam pyrohydrolysis of magnesium chloride dihydrate at 800° C contained 98 percent magnesium oxide. Based on magnesium oxide composition, this is equivalent to that of burned magnesite produced at temperatures in excess of 1,300° C. To demonstrate the quality of the product on a practical basis, metal reduction tests have shown it to be equivalent to reagent-grade magnesium oxide as a carbothermic reduction feed material.

Jan 1, 1974

By George S. Koch

A statistical analysis of silver assay data from rotary-drill-hole cut-tings and diamond-drill-hole cores from the Round Mountain prospect, Custer County, Colo., demonstrates several useful methods for estimating grades and tonnages of ore from the drilling of wide-spaced holes in disseminated deposits of precious metals. A new method of are appraisal is introduced which estimates grade and tonnage of are by calculating convex hulls (smallest convex polygons) for sample points with assay values above specified cutoff grades. Analyses of variance compare the consistency of data from rotary-and diamond-drill holes, from rotary-drill holes sampled at 2-and 4-foot intervals, from two methods of sample preparation, and from atomic-absorption and fire assaying. Evidently, data from the two types of drill holes, from holes sampled at the two intervals, and from different methods of preparation are in agreement. Atomic-absorption silver values are consistently lower than fire-assay silver values.

Jan 1, 1971

By Peter F. Steidl

As part of the Bureau of Mines methane control program, the Upper Free-port coalbed was studied in Fayette County, Pa., where this coalbed lies about 650 feet below the Pittsburgh coalbed and contains the largest remaining reserves of any coalbed in the county. Its estimated recoverable reserves in Fayette County are between 670 and 800 million tons. Coal and overburden isopachs, structure and joint pattern maps, and a fence diagram were prepared using data from gas and oil exploration logs and coal outcrops. These maps will aid in determining the need and/or feasibility of degasifying the Upper Freeport coalbed in the study area. Much of the coalbed in this area is under 600 to 1,400 feet of overburden. By correlation with data from the Pittsburgh coalbed, the gas content at depths of this order is estimated to be between 140 to 300 cf/ton of coal.

Jan 1, 1977

By James A. West

THE South Asian countries of India, Ceylon, Pakistan, Afghanistan, Nepal, Bhutan, and Sikkim have a large variety of mineral resources; however, in spite of mineral industry growth during 1964, development of resources remained far short of possible development, and, in terms of value of trade in minerals, the area remained a sizeable net importer. India's mineral industry is by far the most significant; its minerals production in 1964 accounted for more than 90 per cent of the total value of all minerals produced in the area. The total value of all minerals produced in South Asia in 1964 was only about 1 percent of the area's estimated gross national product of $55,125 million. Despite the rather small current contribution of minerals to the economy, development of mineral resources figures prominently in plans for the industrial development of the nations of this area.

Jan 1, 1966

By J. H. Maysilles

The Bureau of Mines is examining a variety of low-grade uranium ores because projections indicate that an appreciable percentage of future U.S. uranium production will be derived from resources containing 0.01 to 0.1 percent U308. One possible source is represented by a granitic material from Wyoming; the available samples contained 0.06 and 0.12 percent U308. Tests were conducted to explore the general leaching characteristics of this potential resource. The material responded to both acidic and alkaline leaching techniques. Conventional acid leaching extracted 93 percent of the uranium in 18 hours; the required acid addition was 50 to 100 pounds of H2S04 per ton of ore, and the oxidant addition was 3 pounds of NaCl03 per ton of ore. The acid consumption continues after maximum uranium recovery has been reached; this effect may complicate heap or in situ leaching with acidic solutions. Some variation in reagent requirements was noted between the two ore samples. Conventional carbonate leaching with strong solutions at 85° C extracted 94 percent of the uranium in 24 hours. These granitic materials also showed some response to dilute carbonate solutions, and the results suggest that the material may be chemically amenable to heap or in situ leaching with dilute carbonate solutions.

Jan 1, 1977

By J. K. Whyatt, B. G. White

Various methods of monitoring slip movements on bedding planes, as well as examination of rock burst damage in stopes, suggest that many rock bursts in the Lucky Friday Mine are closely associated with these movements. Slip displacements along bedding simultaneously reduce the physical dimensions of stopes and increase compressive stress along stope margins. Such changes, in turn, contribute directly to sudden failures of rock and cemented sandfill surrounding stopes. We believe that the reduction of rock burst hazards must be based on a clear understanding of the basic mechanisms involved. The current work emphasizes the mechanical role of wall rock movement and seismicity in generating conditions that promote rock burst damage. Based on our interpretations of these mechanisms, we briefly address several hypothetical practices that could influence rock burst hazards in similar mining situations. The overall goal of this research is to advance the NIOSH mission of improving the health and safety of the nation’s workers.

By D. S. Colby

The productive capacity of natural gasoline and cycling plants in the United States or. January 1, 1954, was 926 thousand barrels per day, according to the Bureau of Mines biennial survey. This represented an increase of 114 thousand barrels per day during the 2-year period since the last survey. In the previous 2-year period, capacity had increased 164 thousand barrels per day. The total number of plants increased from 521 on January 1, 1952, to 535 on January 1, 1954. The number of operating plants increased from 506 to 521. The major increases in capacity took place in Texas, Illinois, Oklahoma, Louisiana, and New Mexico, with the absorption-type plant continuing to account for most of the new construction. In 1954, however, 6 plants reported using a refrigeration process whereas only 1 plant reported this in 1952. The number of operating compression-type plants continued to decline and combination plants showed a decline this year because a number of these plants were reclassified as absorption-type.

Jan 1, 1954

By A. V. Petty

In accordance with its objective to maximize minerals recovery from secondary domestic resources, Bureau of Mines conducted research on recycling chrome refractory wastes. Since 20 pct of the U.S. demand for imported chromite is used in the production of refractories, primarily for the steel, copper, and glass industries, samples of used chrome-containing refractories from copper converter and reverberatory furnaces were investigated to determine their potential for recycling. The samples were beneficiated using a combination of wet magnetic separation, flotation, and leaching techniques, and the concentrates were reformed into briquets for refractory evaluation. Small refractory test specimens produced from the beneficiated concentrates gave modulus of rupture values at 1,350° C comparable to those of commercial mag-chrome brick of similar composition; however, grinding the waste refractories to at least minus 65-mesh was required in order to liberate the metallic copper. Most of the copper was easily recovered using conventional beneficiation techniques, but the finely ground chrome concentrate would require briquetting, calcining, and crushing to produce a coarse grain suitable for recycling into secondary mag-chrome refractories.

Jan 1, 1981