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By R. R. Wells

For several years the Klukwan deposit near Haines, Alaska, has attracted interest as a potential source of iron. Limited field and laboratory investigation has indicated that the deposit contains a large amount of Iron that is recoverable as high-grade concentrate. This report summarizes the results of laboratory beneficiation testing of the Klukwan ore, as represented by six samples submitted to the Alaska Experiment Station of the Bureau of Mines, Juneau, Alaska, Iron is present in the ore as a fine-grained magnetite associated with a pyroxenite type basic rock.. Satisfactory magnetic-separation procedures were developed for the production of concentrates assaying more than 60 percent Fe and 2 to 4 percent Ti02. During the investigation many data were obtained and compiled, but for convenience and clarity data of secondary importance have been omitted or condensed; only the more pertinent test results are discussed in detail.

Jan 1, 1953

By David C. Oyler

Three long horizontal holes were drilled from a directionally drilled surface hole at the Emerald Mine near Waynesburg, Pa. The purpose was to adapt the technique of directional drilling for use in draining methane from coalbeds. A 504-m (1,652-ft) long, 76-mm (3-in) diameter, circular arc pilot hole was drilled, using a downhole mud motor, to enter the Pittsburgh coalbed at a vertical depth of 305 m (1,000 ft). The hole was reamed to 222 mm (8-3/4 in) and was cased to a measured depth of 486 m (1,595 ft). Three 76-mm (3-in) diameter horizontal drainage holes were then drilled, totaling 2,909 m (9,544 ft) of horizontal hole. Improvements in drilling methods increased the average drilling rate from 20.4 ill (67 ft) to 64.9 m (213 ft) per day. The cost of drilling the directional and horizontal holes (using a Government-owned drill rig) was $1,169,530, a figure inflated by inexperience and by delays caused by lost-circulation problems and fishing operations. An estimated total drilling cost of $960,000 (including rental of a drill rig) for an improved system, was determined by a detailed cost analysis. Initial gas and water production from November 1979 through May 1980 was low because of caving of the horizontal holes drilled in shale near the bottom of the casing.

Jan 1, 1982

By Wendell R. Peters

Shallow underground voids resulting from early coal mining and other resource recovery activities over the past several decades are now being recognized as a significant cause of ground subsidence problems in developing urban areas. Uncertain knowledge of abandoned coal mines also imposes potential hazards in coal excavation operations since water inundation or the release of methane gas is a pricnipal hazard when mine excavation operations break into an abandoned mine. U.S. Army requirements for an effective method for detecting and mapping subversive man-made tunnels have resulted in a surface-operated automatic earth resistivity survey system with a digital computer data processing system. Field tests aimed at demonstrating the system performance resulted in successful detection of tunnels having depth-to-diameter ratios up to 15 to 1. Under the sponsorship of the Bureau of Mines, a similar system was designed and constructed for use in the detection of coal mine workings. This report discusses the hardware and software aspects of the system and the application of the high-resolution earth resistivity method to the survey and mapping of abandoned coal mine workings. In the field tests reported, the targets of interest were both air-filled and water-filled workings.

Jan 1, 1980

By Oliver C. Ralston

Nonmetallic technologic investigations of the U. S. Bureau of Mines are headquartered at experiment stations in three widely separated localities of the United States. During 1936, the Nonmetals Division of the Technologic Branch was formally set up by combining the direction off the work of these three experiment stations under one administration. The New Brunswick (N.J.) station which in the past has been known as the Nonmetallic Minerals Experiment Station, is henceforth to be at College Park, Md., as part of the Eastern Experiment Station, and its principal activities will be related to the nonmetallic resources of the Eastern and New England States.

Jan 1, 1937

By W. W. Adams

The year 1937 was signalized by increased employment in the metal-and nonmetal-mining 4 industry of the United States. Measured by the number of men working, there was a 17-percent gain in employment compared with 1936. In total number of man-hours worked at all mines, the gain was slightly over 18 percent. Hazards connected with mining resulted in more accidents to the workers than in 1936, but the increase in number of accidents caused only a slight rise in the accident rate because of the much larger increase in the number of man-hours worked. In fact, the fatality rate per million man-hours of exposure was lower in 1937 than in 1936, but the rate for nonfatal injuries increased slightly.

Jan 1, 1940

By W. P. Yant, R. R. Sayers, H. W. Shoaf, John Chornyak

"The contemplated use of dichloro-difluoro methane in domestic and commercial refrigerating appliances and in air-conditioning equipment for Public buildings and possibly homes, brings attention to the health hazards involved in a wide potential exposure of the public to vapors of another new product, and for the first time to vapors of an organic fluorine compound. The objective in the development of this new refrigerant, however, has been the mitigation of health and explosion hazards in automatic refrigeration, and accordingly these factors have been given primary attention. Early in the development, the Bureau of Mines was requested to make a laboratory study of the toxicity and potential hazard:"" and it was on the basis of the results of this work and the results of a preliminary investigation made in another laboratory5 that the compound has been selected for commercial use. Although the investigation conducted by the Bureau of Mines is still in progress, information has been obtained to indicate the order of the toxicity and the magnitude of the health hazards involved in the use of dichloro-difluoro methane as a refrigerant. The following is a summarized report of the work completed to date:Additionally work rich is in progress at the present time includes a determination of the lethal time-concentration curve for animals and a study of the response of persons within the range of safe concentrations.The writers desire to jive acknowledgment to T E. Midgley, Frigidaire Corporation, Layton, Ohio, for suggesting the investigation, for arranging for the cooperation of the Frigidaire Corporation, and for advice during the experimental work; to Robert A. Kehoe, The Eichberg Laboratory of Physiology, University of Cincinnati, Cincinnati, Ohio; and E. R. Hayhurst, college of Medicine, Ohio State University, for consultation and advice in planning the work; and to the following employees of the Bureau of Mines for assistance in performing the experimental work: L. M. Berger, chief scientific aid, S. J. Pearce, junior chemist, and Ethel B. Stead, technician."

May 1, 1930

By Wm. W. Odell

This report comprises a brief outline of the experimental cracking of natural gas in a water-gas generator at Louisville, Kentucky, and a discussion of the results obtained. The work was done under a cooperative agreement by the U. S. Bureau of Mines with the Louisville Gas & Electric Co. The re-forming or partial cracking of natural gas is not a new process, but one which has been employed in the manufacture of city gas for a number of years. However, the apparatus used heretofore was not a water-gas generator containing a bed of ignited fuel, but instead it was a plurality of connected chambers containing spaced and arranged checker bricks, with means for heating the bricks and for admitting the natural gas. The procedure previously followed was quite different from that used during the tests at Louisville; likewise the results obtained were different. It is not uncommon for companies distributing natural gas to provide gas-generating equipment for producing manufactured gas which is used, mixed with natural gas, during periods of peak demand. Because this equipment is idle much of the time, in some instances being in use only for a few days a year, some of the gas companies have considered using it, during off-peak periods, in the manufacture of some gaseous products and for carbon black which might he produced and marketed with profit. There is one plant of this kind at Louisville. Kentucky. Its maintenance in condition ready to be operated is necessary because of the limited supply of natural gas and because of the variation in demand. The engineers of the Louisville Gas & Electric Co. considered in particular the possibility of cracking natural gas in a water-gas generator by injecting the gas into the incandescent fuel bed, thereby producing a gas comprised largely of hydrogen (H2) and carbon black, an appreciable amount of which is entrained in the gas as it leaves the generator, Because power and gas are available at low prices, Louisville was believed to be a satisfactory location for a plant which could use hydrogen. It was evident that this method of treating natural gas might directly benefit the gas company by: 1. Lowering, the cost of manufactured gas.

Jan 1, 1930

By M. J. Ferrante

A process was investigated for preparing Specification-grade nickel (containing less than 1 percent cobalt) by stripping it electrolytically from a nickel sulfate-boric acid solution and using the stripped electrolyte for the preferential dissolution of nickel from basic carbonates of nickel and cobalt. The basic carbonates were produced at the plant at Nicaro, Cuba, owned by the U.S. Government. Determination of the optimum conditions for deposition of Specification-grade nickel indicated that the upper limit of cobalt concentration was 0.1 gram per liter. The pH, temperature, and concentrations of nickel and boric acid in the electrolyte were not critical. An aluminum cathode and two lead anodes were used at a cathode current density of 1.2 amperes per square decimeter.

Jan 1, 1959

By A. B. Hooker

Investigations at the Pittsburgh Experiment Station of the Bureau of Mines have shown that satisfactory operation of a flame safety lamp depends not only upon proper design and assembly of the lamp but also upon the kind

Jan 1, 1945

By Robert S. Warfield

The Federal Bureau of mines and U.S. Geological Survey conducted exploratory investigations and geologic mapping in the Wishbone Hill district of the Matanuska coalfield almost continuously from 1942 through 1958. These investigations delineated reserves of high-volatile bituminous coal necessary to supply the rapidly expanding military and civilian requirements in the Anchorage area. This report describes the program conducted by the Bureau of Mines from 1949 through 1958, and briefly summarizes previous investigations, the results of which have already been published. The coal-bearing structure on both the north and south limbs of the prominent Wishbone Hill syncline was explored by 8,719 feet of churn drilling and 25,460 feet of diamond-core drilling. A total of 33 holes were drilled ranging in depth from 60 to 2,114 feet. To supplement the drilling operations, bulldozer and dragline trenching were undertaken at key locations; about 25,000 cubic yards of dragline trench were excavated in the vicinity of the old Premier mine.

Jan 1, 1962

By Albert S. Konselman

This paper describes the mining methods and operating costs for 1938 at the South Burns shaft, situated in the Cripple Creek district, Colorado. The shaft is operated by Golden Conqueror Mines, Inc., through which portions of the properties of the Acacia Cold Mining Co., The Free Coinage Gold Mining Co., and The United Gold Mines Co. are worked under lease. During 1938, 30,773.61 dry tons of ore averaging $9.59 in gold per ton was mined. Of this, 10,138.439 tons averaging $10.65 per ton was produced on company account, and 20,635.171 tons averaging $9.05 per ton was produced by "split-check" lessees.

Jan 1, 1940

By Oliver Bowles

The following discussion of waste rock utilization constitutes the fifth paper of the current series of reports on lime- plant quarry problems . As here tofore lime manufacturers are invited to cooperate to the fullest extent by supplementing the Bureau's information with the results of their own experiences and observations . Waste utilization is the key to success in many enterprises , and with a broader knowledge of this branch of the lime industry more economical operation is made possible . Your assistance in compiling additional data on this subject is solicited , and such assistance may be rendered by writing answers to the questions on the final page of this report .

Apr 1, 1923

By E. A. Johnson

The Bureau of Mines determined the effect of slag additives on copper solubility and the distribution of typical impurity elements between copper-iron matte and silica-saturated fayalite (iron silicate) slag at 1,250° C, in CO-C02 atmospheres with 10 pct S02. Small additions (<10 pct) of CaO, A1203, and MgO were shown to decrease copper solubility in the slag. Additions of CaO increased the solubility of bismuth and tellurium in the slag at lower matte grades. Al 20 3 additions decreased the solubility of tellurium in the slag, but increased that of bismuth at lower matte grades. A1203 additions increased the solubility of both at lower matte grades. With no additives, matte grade did not affect the solubility of bismuth in slags, whereas increasing matte grade resulted in a slight decrease in the tellurium solubility in slag. Additions of CaO or As203 alone to the slag increased selenium and arsenic distribution to the matte, but had little or no effect on antimony distribution; whereas small MgO additions decreased antimony distribution to the matte but had no effect on arsenic and selenium distribution. In slags with no additives, selenium distribution to the matte increased with increasing matte grade, while that of antimony decreased and that of arsenic was unchanged.

Jan 1, 1982

By H. P. Hermance

The Ely mine, which at one time was the largest producer of copper in the United States, has been idle for the past 30 years. A remarkably continuous ore shoot probably averaging 100 feet wide and 19 feet thick was mined on about a 25° slope for 3,400 feet on the incline. The ore was massive sulfides containing chalcopyrite, pyrrhotite, pyrite, and sphalerite. The estimated production of the Ely mine is 400,000 tons of ore averaging 3.3 percent copper. Because of the critical position of copper during the recent war, a search for extensions and recurrences of parallel ore shoots at the Ely deposit seemed warranted. The Bureau of Mines surveyed selected areas by geophysical methods, diamond-drilled nine holes, and sampled mine dumps during its investigations, which began in 1942 and terminated in 1946. The diamond drilling totaled 5,229 feet. The logs of the holes include chemical analyses of mineralized sections.

Jan 1, 1949

By F. J. Gallagher

Some serious fires have occurred in bituminous-coal mines because of short circuits on direct-current power systems that do not have adequate circuit-breaker protection. The writer&apos;s observation of circuit-breaker installations in numerous coal mines leads to the conclusion that many persons am not properly informed as to the true functions, limitations, and operation of circuit breakers. Faulty protection results in fire hazards that endanger lives and property. Proper circuit-breaker protection would greatly minimize or, in many instances, eliminate the hazards; moreover, many operating advantages of proper application of modern circuit breakers would be gained. The purpose of this circular is to show why fire hazards exist in many mines despite the use of circuit breakers and how, the hazards may be overcome. A method is given for determining whether additional circuit-breaker, protection is required for a specific 250/275-volt direct-current distribution system, and, if so, the approximate locations and capacities of the required supplemental breakers.

Jan 1, 1951

By S. M. Dar

The U.S. Bureau of Mines constructed a full-scale model of a 15-ft-wide coal mine entry to use in combination with finite-element analyses to investigate roof support systems and various types of roof bolts. The objective was to enhance understanding of the fundamental mechanics of the interaction between rock and supports and the relative integrity of bolted mine roof as a function of roof bolt type, length, spacing, and tension, and the basic characteristics of the roof strata. The laboratory test results, when correlated with computer simulations using fmite-element analysis and underground verification tests, should provide a basis for desigillng safer, more cost-effective roof control systems and help to establish guidelines for employing fully grouted resin and mechanically anchored bolting systems. The background for this research, the research approach, the methods and equipment employed, and the results are described in this report.

Jan 1, 1989

By J. C. Hartley

The most important single operation in mining is the ventilation of underground areas in a manner conducive to the health and safety of employees. Adequate volumes of pure air must be supplied at the working faces, along the haulageways, and wherever men work, so as to dilute and carry away the methane liberated from the coal and adjoining strata, noxious gases evolved by the use of explosives, and the carbon dioxide exhaled by men and formed by oxidation of carbonaceous material, as well as any other gases, and also dusts which may be found in mine workings. A sufficient quantity of air must also sweep abandoned or worked-out areas of the mine to prevent the accumulation of gases, where sealing methods are not utilized to isolate old workings. Air, in a quantity adequate to meet the needs of the particular mine to which it is applied, is necessary, and supplying it can be made very expensive through failure to observe good practices in its direction and apportionment." Leaky stoppings, doors, and overcasts rob the working faces of air and add to the ventilating cost by burdening the fans with fugitive air,

Jan 1, 1944

By W. T. Abel

The difficulties associated with wet-processing fine size coal led the Bureau of Mines to investigate a dry process for removing pyrite from coal pulverized to powerplant fineness. The dry process that was investigated consists of two cleaning steps: First, centrifugal separation is used to remove a fine, pyrite-depleted portion as a product; second, the remaining coarser, pyrite-enriched portion is taken to electrostatic separation in which pyrite is concentrated and rejected. Ball milling and Hardgrove milling were used to pulverize the coal. Three coals from the Pittsburgh seam were treated by the dry-removal process. Over 55 pct of the pyrite, which amounted to 70 pct of the available pyrite, was removed in a reject of 10 to 20 pct from one of the coals. Similar treatment of the other two coals removed about 35 to 50 pct of the pyritic sulfur, which amounted to about 70 pct of the available pyritie, sulfur from these coals. Both centrifugal and electrostatic separations were more efficient when pyrite particles were as large as possible. Separation efficiency was improved by confining the particle size of the feed to a relatively narrow range and by avoiding excessive amounts (more than 10 pct) of dust in the electrostatic range. The removal efficiency was increased with the use of stage grinding.

Jan 1, 1973

By H. Kenneth Sacks

The Bureau of Mines has developed hardware for electromagnetic (EM) detection and location of miners trapped in underground coal mines. This report describes a technique for using the developed equipment for locating uncased boreholes underground. Results of several field and laboratory experiments are described.

Jan 1, 1978

By Ludwig Schmidt

Investigations conducted by the Bureau of Dines pertaining to the reduction of evaporation losses of petroleum have shown that such losses may be reduced 70 to 80 per cent by the use of vapor-tight tanks equipped with vacuum and pressure relief valves, and vapor-tight thief hitches. Additional studies have shown that it is often economical to supplement this type of construction with other measures that will reduce evaporation losses still further. Water-cooling systems, insulation, and light colored paints are the measures most often used in connection with vapor-tight tanks. Painting with light colored paints probably is employed in the greater number of cases. On account of the cost of insulation, or of installing water cooling systems, the use of these methods are restricted to tanks containing gasoline or crude petroleum with a very large content of low-boiling fractions. The effect of cooling systems has been discussed in a previous report.2 In choosing paints for tanks many factors must be considered. Probably the three most important are cost, protective value, and color. Many companies have adopted a standard color for all of their tanks in this way they reduce the initial cost of paint by buying in large quantities. The tank farms of such companies usually have a neat appearance, resulting from the uniform painting of all tanks. This procedure also has advertising value. Unfortunately, most of the paints used to protect steel are of the darker colors, usually red or black. These colors accelerate the rate of evaporation. Several companies have solved this difficulty by using a dark colored metal-protective paint as a primer coat, and a paint of any desired color for the final coat. Special metal-protective primers to be used under light-colored cover coats have been placed on the market by several paint manufacturing companies.

Jan 1, 1925