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By John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By C. A. Kumke

The Korean crisis and the cessation of Russian manganese-ore shipments to the United States in 1950 reemphasized the almost total dependence of the domestic steel industry on foreign supplies for metallurgical-grade manganese ore. In this emergency, Congress authorized the Bureau of Mines to undertake experimental mine and process development work on the known large reserves of low-grade manganese ore in the Artillery Mountains region in Mohave County, Ariz. The objective of the work was to obtain the basic mining and metallurgical data needed to make specific plans for initiating exploitation of the deposits within 3 years if high-grade foreign ore could not be obtained during the emergency. The manganese deposits of the Artillery Mountains region are in an area of about 25 square miles on the north side of the Bill Williams River in southern Mohave County. Lasky, of the Federal Geological Survey, has estimated reserves at 175 million tons of manganiferous material assaying 3.5 to 4 percent Mn. Although the man¬ganese occurs in various Tertiary and Quaternary formations as both bedded and fissure vein deposits, the more important syngenetic deposits are found in upper and lower manganiferous zones in the sedimentary beds of playa and alluvial fan origin that constitute the Chapin Wash formation.

Jan 1, 1957

By Miro Mihelich

The mines and prospects in the vicinity of Landlocked Bay, 25 miles southwest of Valdez, Alaska (fig. 1), were examined, mapped, and sampled in July and August 1955 as part of a comprehensive investigation by the Bureau of Mines of ore deposits adjacent to Prince William Sound. The purpose of the investigation is to establish and record the location, nature, extent, and metallurgical characteristics of copper and associated metallization in the Prince William Sound district and to indicate, if possible, those areas in which additional exploration and development may be justified. Of particular interest are the possibly numerous deposits of massive iron sulfides that were neglected during early mining operations. These deposits may constitute important reserves of sulfur and iron. At Landlocked Bay deposits of copper-bearing iron sulfide minerals have been mined or partly explored through mine workings, which are in a zone about 1 mile wide along the western side of a large overthrust fault known as the Landlock Overthrust. Eight of the principal mines along this zone were examined end sampled. Although only three of the mines have a recorded production of shipping-grade copper ore, all have deposits of copper-bearing iron sulfide minerals that are similar in occurrence. The deposits occur as lenticular masses and disseminations of chalcopyrite, pyrite, and pyrrhotite which replace crushed rock or fill cavities along shear zones in greenstones and in sedimentary rocks that are exposed between sea level and an altitude of 2,500 feet. These lenticular masses of sulfide minerals range in size from small pods to ore bodies that have been stoped to maximum widths of 9 feet, strike lengths up to 70 feet, and dip lengths as much as 350 feet. Where accessible for sampling,, the copper content of the deposits ranged from a few hundredths of a percent to over S percent; zinc, gold, and silver are present in negligible amounts. Flotation tests of a sample composited to represent typical mine-run ore indicate that 81 percent of the copper is recoverable in a product assaying 28 percent copper at a concentration ratio of 17.5 : 1. INTRODUCTION Statistical records indicate that approximately 110,000 tons of metallic copper (about 16 percent of total Alaskan production) was produced from mines adjacent to Prince William Sound during the 40-year period ended in 1938. Although the principal production was from a large-scale mining and milling operation on Latouche Island (Kennecott Copper Corp., Beatson mine), a substantial amount of the total copper was derived from direct-shipping ores selectively mined or hand-sorted from numerous other deposits in the district. No production has been made since 1938; many of the claims have long been abandoned, and mine workings are either caved or deteriorating rapidly.

Jan 1, 1957

By Irving Hartmann

At the 9th International Conference of Directors of Safety in Mines Research a paper6/ was presented describing the initial phases of research by the Safety in Mines Research Establishment at Buxton, England, on the remote control of timber fires with high-expansion foam plugs in a rock tunnel. The work received extensive publicity, and great interest was aroused by the implied possibility that the method might be used successfully to control coal-mine fires, which for various reasons cannot be approached and attacked by standard fire fighting measures and frequently require sealing extensive, valuable coal properties and lead to loss of production and coal reserves and occasionally loss of lives. To investigate the practicability of the foam-plug technique under American min¬ing conditions, with room-and-pillar-type extraction and multiple entries, the Bureau of Mines in 1957 began an investigation at its Experimental Coal Mine, Bruceton, Pa, In preparation for this work it was necessary to rehabilitate and reinforce an elliptical tunnel in the mine where studies had been made, many years ago, leading to development of a ventilation system used in the Holland Tunnels between New York and New Jersey, and in many other vehicular tunnels.

Jan 1, 1958

By W. M. Mahan

This report describes work carried out by the Federal Bureau of Mines in cooperation with the General Services Administration (GSA). Tests on nickel oxide reduction were conducted at the Pyrometallurgical Laboratory at Pitts-burgh and Bruceton, Pa., and at a rented plant at Canonsburg, Pa. Nickel oxide was reduced to sponge nickel, which was then melted to produce specification-grade nickel ingots containing a minimum of 98.50 percent nickel plus cobalt and a maximum of 1.00 percent cobalt. One purpose of this study was to determine if specification-grade nickel could be made from nickel oxide produced at the United States-Government-owned plant at Nicaro, Cuba, in pilot-plant scale operations involving direct reduction and melting processes. A second and equally important purpose was to obtain cost data on the pilot-plant operation to estimate the cost of producing ingot nickel at an annual rate of 12 million pounds. Laboratory tests verified that nickel oxide, in saggers and in the presence of anthracite fines and dolomite in the ratio of approximately 20:5:1, could be converted to sponge nickel when heated to approximately 1,900° F. for about 2 to 4 hours, depending on the size and density of the oxide charge. The tests also determined the type of saggers suitable for pilot-plant operations.

Jan 1, 1959

By V. B. Dale

This is one of a series of reports covering the mineral resources of the Nation. It describes briefly most of the known tungsten deposits in Yuma, Maricopa, Pinal, and Graham Counties, Ariz. Most of those described were examined by the author. An effort was made to determine the position of the various deposits by section, township, and range and to give accurate road direction to each property from a prominent landmark. All available maps have been used in making these determinations, but in unsurveyed areas it was necessary to make approximate projections of subdivisions. The township and range numbers refer to the Gila and Salt River base and meridian.

Jan 1, 1959

By V. B. Dale

This paper is one of a series covering the mineral resources of the Nation. It briefly describes most of the known tungsten deposits of New Mexico. Most of the descriptions are from field examinations by the senior author. Reported tungsten occurrences that were not visited are listed below: Colfax County: Occurrences of ferberite in thin veins in Willow Creek near Elizabethtown.4/ Dona Ana County: Small, low-grade occurrences of scheelite near the summit of the Organ Mountains about 15 miles east of Las Cruces. Hidalgo County: Scheelite reported in the Daisy mine 7 miles southeast of Hachita. Ores are carbonates containing copper, gold, silver, and bismuth.5/

Jan 1, 1959

By R. J. Leary

The natural gas-air burner described in this report was designed and constructed to meet the thermal requirements of a convective process for heating steel scrap. This process involved downward combustion of natural gas with air, blending the combustion products with diluent air, and then passing this tempered stream of gases downward through a porous bed of steel scrap contained in the furnace chamber. The scrap would be heated to a temperature limited by the adiabatic flame temperature of the gas stream in a period that depended on the rate at which heat was supplied per unit of bed cross section. The temperature of the gas stream would be limited to that beyond which an objectionable degree of oxidation would occur; for carbon steel this limit had been found to vary from 1,900° to 2,100° F. with the superficial velocity of the gas stream. The productivity of the process was dependent on the rate of heat input per unit of furnace cross section; for the 3-foot-diameter experimental furnace an input of 680,000 B.t.u. per hour was desired. The burner described was designed to meet these conditions of temperature and heat input. It provided for three streams of entering gases: (1) A primary air-fuel mixture too rich to be combustible, that is, above the upper flammable limit; (2) secondary air for combustion of the primary mixture; and (3) tertiary air, principally for cooling the combustion products to the temperatures desired for process operation. Downward combustion of the primary and secondary streams occurred in a flame stabilized on an annular port, while tertiary air flowed in an annular path surrounding the port and also through an axial channel whose wall formed the inner ring of the annular port. This burner performed beyond the designed heat-input rates while producing stable flames, which were adjusted readily to the temperatures desired. Gas-stream temperatures were easily controlled to within 15° F. of the desired value by simple manual adjustment of the flow valves.

Jan 1, 1959

By Joel N. Van Sant

THIS REPORT describes the occurrence, mining, and use of refractory clay in Colorado within Region III of the Federal Bureau of Mines, which includes the States of North arid South Dakota, Nebraska, Wyoming, Colorado, Utah, New Mexico, and Arizona. Field work by the Bureau of Mines, United States Department of the Interior, included examination of active and abandoned refractory-clay mines as well as a reconnaissance survey and sampling of numerous clay-bearing formations exposed in Colorado. Information from the survey and the sampling will help guide private industry in its search for virgin sources of refractory clay. Library research of published and unpublished reports from various Federal, State, and private sources was conducted during the early phase of the investigation. Most of the refractory clay mined in the Denver-Golden district of Colorado is not used for refractory purposes but is blended with other clays in the manufacture of structural clay products. The predominantly flint-clay de-posits in the Pueblo and Fremont County districts are mined and utilized chiefly in fabricating refractory products.

Jan 1, 1959

By R. F. Tenney

This report has been prepared because little detailed information has been published on the production and use of anthracite producer gas for industrial-process and brick-kiln heating. To obtain this information, an investigation was conducted by the Federal Bureau of Mines in cooperation with a building-brick manufacturer (firing both periodic and tunnel kilns with anthracite producer gas) and with a manufacturer of anthracite-gas producers. In addition to a study of available plant records, 2 weeks was spent in systematic observation and measurement during regular operation of the Hazleton Brick Co. plant, Hazleton, Pa., in July 1953. This report presents the results of this investigation and a description of producer and periodic-kiln equipment, operating procedures, and labor requirements. A summary of the conditions of producer and kiln operation is given for the 2-week observation and for the 11 preceding months. The two 10-foot standard anthracite-gas producers consumed 301 tons of Rice and Buckwheat No. 1 anthracite, as delivered, averaging over 13,000 B.t.u. per dry pound during the 2-week period, with a producer hot-gas efficiency of 95 percent, at an average gas offtake temperature of 5400 F. The yield of gas5/ of 153 gross B.t.u. per cubic foot amounted to 140,000 cubic feet per ton of fuel as fired, or 73,500 cubic feet per kiln heating hour, which was sufficient for kiln requirements.

Jan 1, 1960

By R. F. Tenney

The performances of four anthracite-burning stokers have been observed under identical 74-hp. steam boilers. Fifty runs of 12 and 24 hours' duration were made in accordance with the test code of the American Society of Mechanical Engineers (ASME). The capacity of each stoker for burning anthracite has been determined, the heat efficiency at each fuel rate has been computed, and the various significant items of hear loss have been estimated. The operating data and results from each run are tabulated in this report in the form used in the test code. The heat efficiencies and most significant operating data for each run are also presented graphically for each stoker to establish the trends with increasing boiler outputs, The tests show that rice anthracite can be burned on stokers adapted to its use at heat-conversion efficiencies of 82 percent or more under continuous firing. These high efficiencies are maintained with fuel inputs 30 percent higher and lower than the peak efficiency rate. Moreover, a heat efficiency of 70 percent or more is obtained at 50 percent of the optimum fuel rate, even though the excess air into the furnace cannot be held below 150 percent.

Jan 1, 1960

By John C. Holtz

"The Federal Bureau of Mines serves the mining industry by approving equipment that is designed to prevent explosion, fire, shock, or toxic hazards in mines when such equipment is used and maintained in a proper manner, through research, consultation, testing, and inspection, the Bureau studies machinery and component parts submitted by manufacturers and others. Before receiving the Bureau's approval as permissible for safe use in mines, equipment must pass exacting tests and must meet strict requirements established through research and experience and listed in the Bureau's various permissibility schedules. An important phase of the Bureau's research is the testing of diesel engines.Mobile diesel-powered equipment can be used safely in underground noncoal mines and tunnels when mechanical ventilation is provided to dilute and remove the exhaust gas and to replenish oxygen in the underground atmosphere. Safe ventilation is determined by suitable tests of each engine used in a diesel machine. This ventilation cannot be predicted safely, accurately, and economically from any general empirical relationship.In determining safe ventilation, the quantities of carbon dioxide, carbon monoxide, and oxides of nitrogen generated by a diesel engine must be ascertained. These quantities are related to the displacement of the engine, its speed of operation, the design of the combustion chamber, and the fuel:air ratio needed to produce useful power. At overrich fuel:air ratios, all diesel engines generate excessive quantities of toxic carbon monoxide and smoke. The results of engine tests are used to determine a maximum fuel-injection rate at or below which carbon monoxide can be controlled by a reasonable ventilation and smoke is essentially eliminated. Toxic oxides of nitrogen are related to fuel:air ratio and the design of the combustion chamber. Their concentration in the exhaust cannot be controlled by engine adjustments, and each engine appears to have individual characteristics concerning formation of these oxides. Production of oxides of nitrogen frequently is the most important factor in determining safe ventilation."

Oct 1, 1959

By Joel N. Van Sant

The rapidly expanding economy of the West, with its growth of heavy industry, and increased steel production, is primarily responsible for the refractory clay industry's concern over the adequacy of the clay supply in States of the Great Plains and Rocky Mountains. Hence, the investigation by the Federal Bureau of Mines of the occurrence and use of refractory clays in North Dakota, South Dakota, Nebraska, Wyoming, Colorado, Utah, New Mexico, and Arizona has been encouraged by the major consumers and producers of this commodity. The Wyoming investigation is a part of the national program devised to close gaps in the domestic supply of specific types of clays to determine their characteristics and properties and to provide information that will assist the refractory-clay industry. Forty-two locations of clay-bearing rock in 17 areas in Wyoming were examined (fig. 1). Location 3 was not examined during this survey. Its description was taken from an earlier report. Locations 20, 21, and 22 were previously reported but were, also, examined by the Bureau. No samples were collected from these locations because field examination indicated that the shales were not refractory grade. The Hulett, Aladdin, and Newcastle areas are discussed in the section on the Black Hills district; the other 14 areas are described separately.

Jan 1, 1961

By Henry H. Ginsberg

The Federal Bureau of Mines made pilot plant investigations of the process requirements necessary to produce heavy fuel oil by the liquid-phase hydrogenation of bituminous coal. The investigation was carried out in three separate series of experiments. The first series studied the effect of temperature and contact time on product distribution at 3,500 p.s.i.g. and 420° to 480° C. in the presence of 0.1 wt.-pct../ stannous sulfide plus 0.05 wt.-pct. iodoform based on gross coal. As a result of increased contact times and temperatures, the conversion-6/ and yield of hydrocarbon gas increased, the viscosity of product oil decreased, and elimination of oxygen, nitrogen, and sulfur from coal increased. The yield of oil did not indicate any definite trend with changes in temperature and contact time. The yield of oil ranged from 76 to 85 pct. for Pittsburgh coal and from 60 to 85 pct. for Rock Springs coal. Asphaltenes in the product oil ranged from 17 to 38 pct. of the total oil for Pittsburgh coal and from 12 to 22 pct. for Rock Springs coal. Fuel oils meeting Bunker C or American Society for Testing Materials (ASTM) Grade 6 specifications were produced with Rock Springs coal at 0.2- to 1.0-hr. contact time and 440° to 480° C. and with Pittsburgh coal at 0.3- to 1.0-hr. contact time and 420° to 460° C. In the second series of experiments tin, nickel, iron, and zinc were evaluated as catalysts for the hydrogenation of Rock Springs coal to heavy fuel oil at 3,500 p.s.i.g. and 460° C. Using the apparent conversion of coal as criterion of catalyst activity, at a contact time of 0.45 hr. tin was the most effective catalyst; nickel and iron were nearly as effective, but the use of zinc resulted in much lower conversion. When the contact time was increased to 0.80 hr., the apparent conversion of coal was essentially the same for each of the catalysts. When the yield of oil boiling below 3550 C. was used as criterion of catalyst activity, at 0.45 hr. the order of activity was tin, iron, nickel, and zinc; at 0.80 hr. tin was far superior and the others were essentially equal. The product oils contained from 8 to 20 pct. asphaltenes.

Jan 1, 1960

By W. A. Grosh

Records show that much of the lead produced in the Upper Mississippi Valley lead-zinc field was taken from natural openings along crevice systems at shallow horizons or at the surface. During the early history of the district, the shallow deposits were worked intensively; but in recent years the production of lead, except as a byproduct of deeper mining for zinc ores, has not been significant. Considering the methods of early mining, the character of mineralization, and the fact that galena can still be found on the surface of the old digging areas, it was reasoned that enough mineralization might remain on and above bedrock to permit, through the use of modern equipment and methods, economical re-treatment of surface material in the digging areas.

Jan 1, 1960

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions5/ issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1961

By T. A. Henrie

One objective of Project Gnome is to study the feasibility of a phase of the Plowshare program recovering thermal energy from an underground nuclear explosion. The test will be conducted in an underground salt deposit. It is anticipated that some of the energy thus released will be stored as thermal energy in molten salt. This report describes the pre-Gnome experiments conducted at the Federal Bureau of Mines Metallurgy Research Laboratory, Boulder City, Nev. The objectives of this study were to determine the problems involved in the recovery of thermal energy from molten salts to assist in planning the experimental program for the Gnome project.

Jan 1, 1961

By Edward J. Murphy

A comparative study has been made by the Bureau of Mines of several analytical methods for determining carbon monoxide and nitrogen oxides in toxic gases produced by the detonation of explosives. Laboratory and field methods and detector-tube devices are described. Analytical results are compared, and reliability of the various methods is discussed. INTRODUCTION In all underground mining there is ever-present danger to persons from possible overexposure to carbon monoxide and nitrogen oxides created by explosives or blasting agents. These health hazards, recognized for many years, led to the early establishment by the Bureau of Mines of specific requirements regarding fumes generated by explosives authorized for use in underground coal mines in the United States.3

Jan 1, 1961

By Henry M. Harris

Low-carbon shales from 65 deposits and 11 sources of coal-mine waste in western Oregon and Washington were tested in a rotary kiln for their suitability as raw material for expanded aggregate. Shales from 41 sources bloated enough to produce crushed, expanded aggregates, weighing less than 65 pounds per cubic foot in the preliminary tests. The samples were judged on the basis of processing qualities, physical properties, and size and uniformity of the source. Nine low-carbon shale deposits and three coal-mine waste sources were selected for more extensive bloating tests and for examination of the expanded aggregates in concrete shapes. Composite samples from these 12 sources and from 2 commercial operations, when processed for testing in concrete shapes, had bulk densities ranging from 37.S to 72.9 pounds per cubic foot. Damp-cured concrete shapes made with these aggregates had bulk densities ranging from S6 to 119 pounds per cubic foot, and all but three of the lightweight concretes had crushing strengths ranging from 3,270 to 6,810 p.s.i. Properties of the lightweight concretes were compared with those of concrete shapes made with commercial aggregates, and with sand and gravel.

Jan 1, 1962

By David D. Walker

The purpose of the investigation was to describe and appraise tungsten deposits in Montana . The work supplements previous investigations made by Pattee ( 10 ) and Walker ( 17 ) in selected areas of the State . Scheelite deposits in tactite are the most numerous and most important economically , having accounted for nearly all of the State's tungsten production . Of the 64 deposits examined during the current study , 50 contained scheelite , 11 hubnerite , 2 wolframite , and 1 ferberite . The State's major tungsten production has been from scheelite deposits in Beaverhead County . The report lists , by counties , the type and grade of each deposit . The more important occurrences are accompanied by geological and assay maps .

Jan 1, 1963