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By W. H. Oppelt

Two exploratory gasification tests of limited duration were made at Dorsten, Germany, with strongly coking Pittsburgh-bed coal in a fixed-bed pressure gasifier. To reduce the coking potential of the Arkwright coal, ash refuse from the gasification of Dorsten (Leopold) coal was added to pre-pare coal-ash mixtures which contained nominal 20 and 30 percent ash. Major adjustments in principal process variables at the beginning of the tests resulted in wide fluctuations in the rate of gas production, gas offtake temperature, and carbon dioxide concentration in the gas. Because a higher steam-to-oxygen ratio was used in the tests than was customarily employed for routine operation, gas production was lower, and steam and oxygen consumption was higher. After operating conditions had been improved, the results of a 12~-hour-long test with addition of sufficient ash refuse to obtain a nominal 30 percent ash concentration indicated that operation is feasible with this coal mixture using a fixed-bed pressure gasifier equipped with a rotating coal distributor and stirrer.

Jan 1, 1966

By Donald W. Ross

Petroleum oils of widely different grades have long been clarified or decolorized by contact with fuller's earths. More recently, so-called activated clays have also been used for this purpose. Still more recently ouch clays have been used in the form of nodules termed "catalytic pellets." Clays of varied appearance and from different localities possess the desired bleaching qualities, but evaluation of such clays, so useful to the oil industry, has not been simple. Previous methods of identification and evaluation have largely followed procedures of production methods and were not primarily based upon the fundamental properties of the clays. Thus) a false assumption has grown up that) bleaching clays probably have no common properties on which a-method of comparison can be based. Fuller's earths and activated clays have a large absorptive capacity for the color constituents of petroleum and its products decolorizing is accomplished by bringing the oil into intimate contact with the clay and later separating the decolorized oil from the clay with its load of absorbed coloring matter. Former practice in absorbing "color" was to use the clay as granules or In' powdered form. More recent practice is to use clay pellets that are more abrasion-resistant than the granules. The oil is either filtered through a bed of clay, percolation method, or agitated on contact with the clay, contact method. Viscous oils are decolorized at an elevated temperature, so that their viscosity is lowered to the point at which thorough contact with the clay is insured. Nonhumidifying, nonoxidizing gas, such as dry steam or dry nitrogen, is used to seal such hot oil masses from the atmosphere.

Jan 1, 1948

By Charles V. Jude

This U.S. Bureau of Mines report presents a review and evaluation of existing and new backfilling materials and methods for their applicability to the problem of gate road stress reduction in deep retreat longwall coal mines. Candidate backfill materials include pulverized coal combustion fly ash, flue gas desulfurization, and fluidized bed combustion by-products from coal-fired electric power generation plants. Properties of both backfill and its component materials are presented, with particular emphasis on the unconfined compressive strength and elastic modulus of backfill mixtures. Hydraulic mix designs discussed in this report include high-water content slurry and low-water content paste fills. Three gate road stress-transfer-modification concepts are proposed to reduce abutment stresses in gate road systems. The first concept, packwalling, involves packwall construction behind the headgate shield inby the face and adjacent to the headgate pillars. The second concept, gob-filling, involves infilling a strip of gob inset from and parallel to the headgate using paste injection methods patterned after a technology recently developed in Europe. In the third concept, entry-filling, slurry fill methods are used to fill abandoned gate roads and crosscut entries inby the face.

Jan 1, 1995

By R. W. Dougherty

From time to time interest has been evidenced in transporting coal with water in pipe lines. About the year 1895, United States patents broadly covering a method of pumping coal with water through pipelines were granted to W. C. Andrews. His process was used to some extent in pumping anthracite culm and waste back into the worked-out portions of the mines. About 1905, W. T. Donnely was granted patents relating to pumping anthracite silt away from the breakers. From about 1913 until 1924, a British engineer, Gilbert G. Bell, used a short pipeline to convey coal with water from barges on the Thames River to the Hammersmith Electricity Generating Station, London. Minus 5-inch coal was transferred 660 yards through an 8-inch pipe. Some trouble was experienced with fine coal, which tended to plug the line. Bell made several proposals to transport coal by pipeline overland from the Midlands to London, a distance of about 100 miles, but these were never adopted. This survey is concerned mainly with the problems presented by actual pipeline transportation of coal with water. It is assumed that the coal will have been processed to remove most of the abrasive impurities by conventional methods prior to introduction into the line, and that it has been crushed to the required top size. Dewatering at the discharge end of the line is considered part of the conventional cleaning process. There still remain many pump-performance and behavior of water-coal mixture problems that can be solved only by actual performance tests. It is recognized that the distribution of coal to other than very large users is not changed. Large storage areas would be required to supply seasonal markets. Large users, such as power plants and heavy industries, could be supplied by branch lines directly to the point of use, It is also recognized that pipe lines might not be able to carry a full range of sized coal to meet market demands in many areas.

Jan 1, 1951

By M. G. Zabetakis

The use of liquid hydrogen as a high-energy fuel introduces numerous hazards not ordinarily associated with the use of other more conventional fuels. These hazards are attributable to the unique properties of hydrogen in the liquid and gas states (table 1). Since little work has been conducted on explosion and related hazards of cryogenic fuels, a research program was undertaken to obtain basic data on such dangers for hydrogen and other combustibles under these conditions. These data were used to outline emergency procedures for protecting personnel and equipment when an accidental spillage of liquid hydrogen occurs and to establish a quantity-distance table for the storage of this fuel. The vaporization of liquid hydrogen from a surface is treated as a prob¬lem in heat transfer theory. Two extreme cases are briefly considered: (1) The transfer of heat occurs at constant temperature drop between, the boiling liquid and the hot surface, and (2) the transfer of heat is limited by the rate at which it can flow to the surface from a hot insulating medium. The available data indicate that the former case (1) is applicable when vaporizing from a conducting surface and, initially, when vaporizing from an insulating medium; the latter case (2) is applicable after initial flash vaporization has occurred from the insulating medium. The vaporization rate determines in part the rate at which flammable hydrogen vapor-air mixtures are formed above a spill area. However, the rates at which heat is transferred to the vapor, and air is brought in contact with it also are of importance. Accordingly, the distribution of flammable mixtures above a spill area was determined experimentally. In general, flammable mixtures were found to be both above and within the visible vapor cloud.

Jan 1, 1961

Large quantities of combustible materials are often found in underground metal and nonmetal mines, with support timber most often the predominant combustible material. Oils, lubricants, paper, cartons, and rags are additional combustible materials and are commonly found in maintenance shop areas. Welding and cuting, shorted or overloaded electrical cables, spontaneous combustion, and careless smoking are some of the common fire ignition sources. Inexpensive, reliable fire detection and suppression systems are available to provide early warning of such fires and to isolate and extinguish fires that originate in underground maintenance shop areas. Technology developed and demonstrated under Bureau of Mines Contract H024216, Mine Shaft Fire and Smoke Protection System, may be applied to protect underground maintenance shop areas. The mine area described in this report is a representative ex-ample only; the fire protection system described considers costs, benefits, equipment performance and includes the concepts of: ? Early warning and alarm ? Isolation ? Extinguishment ? Control. Each fire protection system application requires analysis of numerous variables including total mine profile (depth, personnel, escape routes, hazards, etc.).

Jan 1, 2011

By Kenneth Wardell

Criteria have been fully developed for determining the optimum size of oil and gas well blocks. The criteria lead to the formation of well barrier pillars which are, of themselves, inherently stable and take account of variable mine roof and floor conditions. The criteria ensure, through considerations of ground movement, that strains transmitted to well casings, are within tolerable limits of casing specifications. The criteria cater for well barrier pillars in multi-seam mining situations and where previous old mining has taken place. The criteria maintain flexibility in being adaptable to local mine design situations. The criteria are applicable to proposed extraction thicknesses up to 15 feet at depths up to 2,400 feet. The criteria are related to producing wells and to abandoned wells. In the latter connection, various states of well abandonment are recognised.

Jan 1, 1980

By J. S. McNabb

"A search for manganese ore by core-drill exploration was carried out by the Bureau of Mines in the Philipsburg mining district in Granite County, Mont., in 1939 and 1940. This work was based on detailed studies of the manganese ore bodies of the district previously made by the Geological Survey.In 1949 further search for manganese in the district was deemed advisable. Diamond drilling was begun the following year as a joint program by the Geological Survey and the Bureau of Mines with the primary purposes of probing ore-leasing structures and extending the limits of known ore bodies. A secondary objective was to test a geologic theory based on a new conception of manganese-ore localization. The exploration targets were designated and the drilling results interpreted by the Geological Survey, and the Bureau of Mines was responsible for the drilling, sampling, and core handling. Improved drilling equipment and methods were utilized in an effort to obtain better core recoveries than resulted from the earlier drilling campaign.The Philipsburg mining district, Granite County, Mont., is 27 miles south of Drurrnnond, about 45 miles airline northwest of Butte, and 1 mile east of Philipsburg. During the course of the investigation patented lode-mining claims owned by the American Machine & Metals, Inc., the Contact Mines, Inc., and the Moorlight Mining Co. were diamond drilled.The district has been an important source of domestic manganese dioxide ore since local recognition of the mineral's importance during World War I. Peak annual output in 1918 of about 127,000 tons of manganese ore was utilized principally by the steel industry. A small but relatively steady output has persisted to the present to satisfy demands by battery manufacturers for battery-grade manganese dioxide.The known manganese deposits of the district are in sedimentary rocks of Paleozoic age. These rocks lie along a north-trending anticline traversed by a series of east-west tension veins. The east flank of the anticline terminates at a steep-dipping fault contact against a small granodiorite batholith.Replacement deposits of manganese oxides and carbonates occur locally in or closely associated with tension veins cutting calcareous rocks, or adjacent to the intrusive. Rhodochrosite has been a common accessory mineral in deposits valuable chiefly for lead, zinc, and silver. Some of the replacement deposits characteristically are irr2gular in outline, whereas others have fairly regular walls marking the limits of favorable beds."

Dec 1, 1955

By W. P. Haynes

To evaluate the potential use of battery-powered vehicles, the Bureau of Mines studied the performance of a battery-powered truck propelled by a 9.6 kw dc motor in considerable detail under various driving conditions. Some of the factors investigated were: Gear ratios, payload (1,468 lb maximum), road grade, stops made per mile, and charging time. With the exception of some difficulty with brush wear, operation and maintenance of the truck was generally trouble-free. On range tests carrying an 868-lb payload a distance of about 50 miles at an average speed of about 19 mph in normal driving, the Bureau's battery-powered truck averaged 1.6 to 1.9 miles per ac kwhr input. Stop-and-go tests indicated that prospects for the use of battery-powered trucks in house delivery service within city limits are good; performance of the Bureau truck was sufficiently high for that type of service. The estimated power cost of 2.65 cents per mile while making 10 stops per mile was attractively low from the standpoint of fuel costs.

Jan 1, 1967

By Thomas M. Barczak

Wood cribs are used extensively by the mining industry to stabilize mine openings. While the cost per crib is relatively low, their extensive use can result in annual mine costs of over $1 million. In an effort to improve the utilization of these supports and to reduce ground control hazards, the U.S. Bureau of Mines has developed engineering methods to assist mine operators in wood-crib design and employment. Design and employment criteria are established based on the strength, stiffness, and stability of the crib structure in relation to the load conditions imposed by the mine environment. Models have been developed based on full-scale tests in the USBM's Mine Roof Simulator that compute the capacity of wood cribs of various configurations and material constructions as a function of displacement of the crib structure due to roof-and-floor convergence. These models permit the comparison of the loading characteristics and costs of employment of different crib designs, and in conjunction with roof behavior models, provide a means to determine the optimum design and employment strategy.

Jan 1, 1993

By Robert H. King

An analysis of low-voltage shielded trailing cables is performed to develop a method for calculating the differences in operating costs between shielded and non-shielded cables. Two types of shield constructions are considered (SH-C and SH-D) for the three major underground coal mining methods. Data from laboratory and in-mine testing are presented in addition to an analysis of safety benefits. Recommendations for further investigations are proposed. Example calculations with sensitivity analyses are presented. Recommendations for further investigation include costs impact considerations.

Jan 1, 1980

By John R. McWilliams

This is one of a series of reports being published by the Bureau of Mines on mining methods and costs at various mines throughout the United States. Including the Holden mine in this series is particularly appropriate at this time. The mine was operated on a low-cost, large-scale production basis to compensate for low-grade ore. Even with the best conditions and the most efficient methods, the margin of profit was small. Under the present situation of rising costs and lowering metal prices, the profit margin vanished. On June 28, 1957, the mine operations ceased; therefore, this report can review the entire life span of the mine.

Jan 1, 1958

By John C. Cook

Channel sand bodies ("wants" or "cutouts") are deposits of barren, hard sediments which interrupt production and pose safety hazards when encountered in underground coal mining. To locate these costly impediments to mining in advance, from the surface of the ground, the seismic reflection method is recommended. High-resolution (high frequency) techniques for shallow seismic exploration of coal beds have been worked out and are reported here, including a field example. Newly-developed high-frequency, digital recording equipment was used, together with light-weight shot-drilling equipment and a variety of down-hole seismic impulse sources. Techniques for rapid but complete coverage of a coal prospect area with a crew of 2 to 6 men n 2 or 3 vehicles are described in detail.

Jan 1, 1976

By David R. Wilburn

The U.S. Bureau of Mines investigated the resources, costs, capacities, market relationships, and short-and long-term supply of bauxite, alumina, and aluminum. The 45 evaluated mines and deposits in 14 market economy countries (MEC's) have a demonstrated resource of 8.4 billion mt of bauxite and an aluminum content of approximately 2.1 billion mt. Developed world bauxite resources and existing primary aluminum smelting and refining capacity are sufficient to satisfy demand through at least 1995, when additional properties (with higher cost levels) would need to be developed to satisfy future demand levels. It is anticipated that new alumina or aluminum production most likely would occur in developing regions with large bauxite potential, low-cost energy sources, and a close proximity to refining and/or smelting capacity. An increase in aluminum recycling capacity would help meet future demand increases. A series of network model supply analyses was performed for the period 1988 through 2000. Based on announced future production levels and assuming demand grows at the level outlined in the analyses, model results indicate there is sufficient material available to meet demand until 1998, where-upon an aluminum shortfall is projected. Additional analyses investigated the effect of a reduced growth rate of demand and regional production variations in Venezuela on the international aluminum industry.

Jan 1, 1993

By Paul W. Johnson

Economic studies of four processes for using the glass fractions obtained from processing municipal incinerator residues are presented. Three processes--brick production, floor tile production, and glass wool production--use the colored glass fraction from an incinerator residue separation plant, and the fourth process, glass spheres production, uses the colorless glass fraction. The fixed capital cost and the estimated annual operating cost for six plants are presented in the report and summarized, as follows: [ ] The value of the product obtained from each of the plants was calculated on the basis of the interest rate of return method. Each of the processes appears economically attractive when comparing the product values with estimated selling prices. However, the effect of the products on market size and price must be determined.

Jan 1, 1973

By Staton L. Tainter

"The Johnny Bull and Silver Knight claims were selected for exploratory diamond drilling after having been examined by the Bureau of Mines 3./The property was considered attractive for two reasons: (1) A prominent outcrop, recognized as an extension of the Tennessee vein, persisted over a distance of 2,000 feet across the claims; (2) its proximity to the known ore shoots in the Tennessee-Schuylkill mine, one of the largest zinc-load producers in Arizona.Actual drilling was started September 18 and was terminated December 8, 1943. Eight holes, aggregating 2,979.5 feet, were drilled with two machines. ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resource to the end that they make the greatest possible contribution to national security and economy. I is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R.G. Knickerbocker, chief, analyses samples and performs beneficiation tests."

Jan 1, 1947

By Frank E. Cash, Max S. Petersen

"INTRODUCTION Explosives have been used in ever—increasing amounts since gunpowder was invented. For hundreds of years only low explosives of the deflagrating type were used, and they were fired by means of a flame or hot object. Ben¬jamin Franklin first ignited gunpowder from a distance in 1751 by means of an electrostatic spark. Further efforts to develop a satisfactory electrical method to ignite explosives from greater distances were overshadowed by the invention of safety fuse in 1831, as this offered a relatively simple and inexpensive means of firing explosives.The discovery and introduction of high explosives of the detonating type and the invention of the fulmitate of mercury blasting cap about the middle of the nineteenth century provided the needed impetus for inventors to develop means of firing the cap by electricity. The original high-tension igniter, following Benjamin Franklin's experiment in which the detonating compound was ignited by a spark, was discarded in favor of a low-tension igniter, in which the detonating compound was ignited by a heated wire. The past 2 decades have seen considerable improvement in the design and construction of electric detonators to make them safer and more efficient, yet in spite of the improvement it is estimated that less than 50 percent of the explosives used in industry today are ignited or detonated electrically. The trend, however, is toward the use of electric methods. In recent years numerous-mining companies have introduced electric blasting exclusively at their mines as a means of improving safety and efficiency."

Sep 1, 1946

By G. F. Kuncir

The analysis described herein evaluates the Bureau of Mines Program for Advancing Mining Technology - Oil Shale in terms of the economic benefits which may be derived for the Nation as a result of its successful research and development efforts. On the basis of postulated oil shale production scenarios, benefit-cost ratio indicators are computed for the program elements as they apply to surface, underground, and modified in situ oil shale mining systems. Eight value indicators are used to measure the Program's beneficial impact on the future oil shale industry in relation to planned research and development costs. These are: capital cost savings, operating cost savings, labor savings environmental quality maintenance cost reduction, reduction in production costs, byproduct production benefits, total production benefits, and additions to recoverable reserves. Program costs are aggregated from 1974 through 1987 and major benefits are accrued from 1982 through 2040. Both cost and benefit streams are discounted to mid-1975 present value.

Jan 1, 1977

By Ross. C. Barkley

A computer program has been written to simulate ground vibrations induced by multiple-hole surface blasts. The program is an inexpensive and relatively easy to use tool for predicting the principal blast vibration characteristics that determine damage and annoyance potential: peak particle velocity, frequency content and pulse duration. The program generates a complete ground motion history by superposing, at any surface position, the vibrations induced by each individual explosives charge. It requires specification of (hence allows accounting for) the blast geometry, initiation sequence (including random delays), position with respect to blast, pulse characteristics induced by each charge, and propagation laws. A methodology is outlined to determine the necessary variables either on the basis of site investigations (e.g. velocity, attenuation, pulse), or by backcalculation from measured blast vibration records. The latter procedure has been applied to blasts from two coal strip mines. Main difficulties are backcalculating individual pulses, propagation (especially dispersion) parameters and delays. A normal distribution of delays, based on published results, has been shown to influence the results and the response of a single degree of freedom structure significantly. Broadening of the wave types included and additional verifications with field results are required.

Jan 1, 1983

By R. S. Dean

"It has long been recognized that the properties of polycrystalline substances are not the same as those of single crystals. These differences are especially marked in metels and metallic minerals, and are of greatest practical importance in metal working and ore treatment. The property changes encountered in passing from a metal single crystal to a poly-crystalline aggregate are the same as are produced by cold-working a metal or by the precipitation of a disperse phase. Hence, we may logically assume that the property changes are all due directly or indirectly to the formation of interfacial area or internal surface. Our problem, then, is to ascertain the physicochemical state of the metal atoms at such internal surface and show how this physicochemical condition accounts for the pronounced changes of mechanical, magnetic, and electrical properties that accompany increased internal surface.GENERAL CONCEPT OF INTERNAL SURFACEIn 1678, Huyghens attempted to explain the double refraction of calcite by postulating that crystals were built from a regular arrangement of ellipsoidal particles. Over 100 years later, Abbé Hauy concluded from his studies of cleavage that crystals might be built from small units, but the units were of the same shape as the entire crystal. This idea, which was prevalent in mineralogical thought before the advent of X-ray spectrometry, was discarded when the great success of Bragg made it appear that the chemical atoms were in reality the elements of structure. In the further development of X-ray technique, however, C. G. Darwin, in England, and P. P. Ewald, in Germany, found it necessary to postulate crystal units con¬taining many atoms. The latter gave the name of mosaic crystals to those so constituted. The individual units are supposed to Possess the ideal atomic arrangements revealed by the X-ray but are not oriented with respect to one another."

May 1, 1938