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"Requests are frequently received by the Information Service of the Bureau of Mines for published information on the coals of different foreign countries, as compared with coals mined in the United States. The analyses of various coals from several countries on the Pacific, which were submitted to the Fuels Division for certain tests between the years 1913 and 1916, may be of interest, and are shown below: Results of Analyses of Various Coals from China, New Zealand, Japan and Australia."

Sep 1, 1925

By Judith L. Bolis

The Bureau of Mines estimated the potential availability of iron ore from 129 domestic and foreign mines and deposits in 25 market economy countries. The availability of four products on a total and regional basis was determined from demonstrated resources of 75.3 billion It. From the resources evaluated there are a total of 18.6 billion It of sinter fines, 4.9 billion It of lump ore, 14.7 billion It of pellets, and 820 MMlt of pellet feed potentially available at a 15-pct DCFROR, f.o.b. port. On a regional basis, at or below a total cost of $0.26 per iron unit there are 1.7 billion It, 2.8 billion It, and 186 MMlt of sinter fines potentially available from Brazil, Australia, and Africa, respectively. There are 825 MMlt of lump ore from Brazil and 1.4 billion It from Australia potentially available at or below a total cost of $0.24 per iron unit. There are 2.1 billion It of pellets potentially available from the United States at or below a total cost of $0.80 per iron unit, while 442 MMlt are potentially available in Brazil at or below $0.38 per iron unit. South America has 208 MMlt of pellet feed potentially available at or below a total cost of $0.28 per iron unit. While the resources of iron ore are more than adequate to satisfy demand, the future of the iron ore industry is very dependent upon changes in the world economy, and on the domestic scene, changes in the domestic steel industry and steel imports.

Jan 1, 1987

By N. Kumar Kittusamy

Operators of construction equipment perform various duties at work that expose them to a variety of risk factors that may lead to health problems. A few of the health hazards among operators of construction equipment are: (a) whole-body vibration, (b) awkward postural requirements (including static sitting), (c) dust, (d) noise, (e) temperature extremes, and (f) shift work. It has been suggested that operating engineers (OEs) are exposed to two important risk factors for the development of musculoskeletal disorders: whole-body vibration and non-neutral body postures. Method: This review evaluates selected papers that have studied exposure to whole-body vibration and awkward posture among operators of mobile equipment. There have been only few studies that have specifically examined exposure of these risk factors among operators of construction equipment. Thus other studies from related industry and equipment were reviewed as applicable. Conclusion: In order to better understand whole-body vibration and postural stress among OEs, it is recommended that future studies are needed in evaluating these risk factors among OEs.

Jan 1, 2004

By W. A. Cole

Underground mining methods at the Gray mine of Tri-State Zinc, Inc., are of special interest because of the low unit costs achieved through use of jumbos and loading equipment mounted un crawler-type tracks and of diesel trucks that haul from the stoping areas to the mill through inclined adits. The operating company, Tri-State Zinc, Inc., is a wholly owned subsidiary of Gold Fields American Development Co., Ltd., the latter being the American branch of New Consolidated Gold Fields, Ltd., a British-owned company.

Jan 1, 1957

By R. H. Church

As part of the research effort of investigating the effects of microwave energy upon the chemical and physical properties of different minerals and ores, the Bureau of Mines has conducted basic research into identifying those properties of minerals that are affected by microwave energy, namely, the dielectric constant and loss tangent. These properties were determined utilizing the theory of microwave propagation in a coaxial waveguide filled with a dielectric material and measuring the input impedance with an RF impedance analyzer that operates from 1 MHz to 1 GHz. By knowing the microwave frequency and filling the waveguide with a powdered mineral, the dielectric properties of the mineral sample were determined. From these dielectric properties, theoretical microwave heating characteristics of each mineral could be calculated. These same mineral samples were then irradiated by a 915 MHz 30 kW variable power microwave oven and dielectric heating studies were performed. A comparison of the theoretical heating characteristics and the results from actual dielectric heating studies was conducted to evaluate the dielectric property measurements on each mineral. This report presents the results of the Bureau's research in identifying the dielectric properties of low-loss minerals according to the mineralogical classification scheme along with their irradiation studies. Though far from complete, this study represents some of the more frequently encountered low-loss minerals.

Jan 1, 1988

By Robert L. Rough, William E. Eckard

Laboratory data obtained from a Bureau of Mines rotary air core of a well near Sugar Grove , Warren County , Pa . , were instrumental in initiating hydraulic fracturing in the area to stimulate oil recovery from Glade sand oil reservoirs . This report outlines the general geology , lease development , reservoir- rock characteristics , and oil - production history of Glade and Clarendon sand reservoirs in Warren County . The methods of well completion for single- stage and multiple- stage hydraulic fracturing of old and new wells are discussed , and a range of hydraulic fracture treatment data from 29 Glade sand and 10 Clarendon sand wells is presented . A composite decline curve representing oil - production data from six wells shows probable results of hydraulic fracturing . Average cumulative oil production during the first 100 days after hydraulic fracturing with a sand - carrying liquid is compared with production after conventional shooting with liquid nitroglycerin .

Jan 1, 1964

By J. M. Kuchta

The Bureau of Mines used laminar hot air jets of l/8- to 3/4-inch diam-eter to determine the hot gas ignition temperatures of various combustible vapor-air mixtures. The combustibles were n-hexane, n-octane, n-decane, a hydrocarbon jet fuel (JP-6), and an adipate ester aircraft engine oil (MIL-L- 7808). Minimum ignition temperatures occurred at a fuel to air weight ratio of about 0.5 and were not greatly sensitive to variations of fuel concentra¬tion. Moderate variations of jet velocity also had little influence on these ignition temperatures. However, these temperatures decreased with increase in heat source dimensions (jet diameter). The hot gas ignition temperatures of the combustibles were not necessarily much greater than corresponding autoignition and wire ignition temperatures when the size (,F the heat source and the ignition criterion were the same.

Jan 1, 1966

By Norman A. Pace

This paper is one of a series being published by the Federal Bureau of Mines on methods and practices used in mining and preparing crushed stone for market. Performance, in terms of units of work or tons produced per machine and per operator man-hour, is given whenever that information can be obtained. Direct operating costs are useful for comparing different methods and are included, if available. In addition to describing equipment and methods used} the Bureau considered it desirable to discuss the engineering reasons for the choices that have been made. This paper is particularly concerned with operation of the Camak quarry and plant of the Weston-Brooker Co. The quarry and plant are near Cedar Rock, north of State Highway No. 80 and east of Middle Creek in Warren County, Ga., and about 40 miles west of Augusta. Rail access is by a spur line of the Georgia Railroad from Camak, 5 miles southwest. The main office of the company is at Cayce, S. C.

Jan 1, 1959

By James H. Aase

[This study provides data on the physical and hydrological makeup of the ,t hakes waterway system and forecasts quantities, traffic patterns, and ping cost of prospective bulk mineral commerce projected to be transported it. Factors affecting the shipping cost of iron ore, bituminous coal, imestone were quantified and integrated into a computer program that can d to estimate costs under varying sets of conditions. Combined ship of iron ore, bituminous coal, and limestone in 1995 were estimated at million tons. The cost of operating the U.S. vessel fleet for trans-ng an indicated 80 percent of this traffic tonnage was projected to be $163. 5 million.]

Jan 1, 1970

By Beatrice Lukens, David Schlain, John D. Prater

"The electrolytic manganese process4/ developed by the Bureau of Mines involves the electrolysis of a solution of manganese sulfate and ammonium sulfate in a diaphragm-type cell. Metallic manganese is deposited on the cathodes, and sulfuric acid is produced at the anodes. The spent electrolyte contains, in addition to the sulfuric acid, approximately 40 percent of the manganese sulfate and most of the ammonium sulfate originally present in the feed solution. This spent solution is used to leach fresh ore that has previously been subjected to a reducing roast. The resulting leach liquor is purified and returned to the cell.Manganese of very high purity is produced by the electrolytic process. The properties of this metal are so different from those of the best grade of manganese that can be made by any other commercially feasible process that it is virtually a new material. Electrolytic manganese has been used in the preparation of new high-manganese alloys with valuable properties.3/ and further developments are to be expected. The electrolytic manganese process not only results in a product of superior qualities, but is applicable to large tonnages of domestic ores that are unsuitable for direct use in producing ferromanganese.The future industrial use of electrolytic manganese is of course, related to its cost. Decreases in the cost of production will lead to wider use of the metal; conversely, increases in the volume of production made possible by greater demand will bring further .decreases in cost."

May 1, 1946

By W. W. Odell

"It has long been recognized that coke is a more desirable fuel than bituminous coal in water-gas apparatus of present design, but still considerable headway has been made in the use of the latter fuel as a substiaute for coke. This is particularly true in the Central States where the supply of high-grade coke has been very limited and uncertain during the past few years, and where coking coals of low sulphur content were available in quan¬tities. In fact, with, the present difference in price of coal and coke, it is possible to realize a marked saving when using a coking bituminous coal as generator fuel.Difficulties have been encountered in the use of such fuel, but they have, to a large extent, been overcome. One of the chief obstacles in the use of the more general utilization of bituminous coal for water-gas manufacture, is the fact that, with normal operation, the capacity per unit of time is reduced. This of course is a serious problem for plants operat¬ing at capacity with coke fuel. However, this difficulty can, to a large extent, be remedied by a changed method of operating, and can be entirely remedied by a combination of the latter with a change in the design (or proportions) of a water-gas set. The preceding statement, the reader will understand, refers more particularly to a carburetted water-gas set.In the manufacture of water gas from coke, present practice requires that for continuous 24-hour service the heat of combustion of all the carbon monoxide (CO) generated during the air blow be utilized in addition to the sensible heat of the gas coming from the generator. This is doubly true when making carburetted water gas from bituminous coking coal. The reasons why this is so are apparent when the following factors are considered."

Nov 1, 1920

By B. D. Nash

The Bureau of Mines continued its research into the recovery of fluorine by the phosphoric acid acidulation defluorination of phosphate rock concentrates. A small process development unit with a capacity of about 10 kilo-grams of charge per hour was operated, and concentrates from both Idaho and Florida were processed. Over 80 percent of the fluorine was evolved and recovered as a dilute fluosilicic acid solution. Phosphate extraction from the concentrates always exceeded 98 percent. The fluorine was converted to a synthetic fluorspar product (3CaFa?SiOa) suitable for use as a slag conditioner in electric furnace steelmaking operations.

Jan 1, 1977

By D. S. Kingery

Investigations over several years have disclosed that the principal manners of occurrence of shuttle-car injuries are in order: 1. Victims in contact with roof or crossbars. 2. Victims in contact with ribs or timber legs. 3. Victims falling from, or jerked from, shuttle cars. 4. Victims in contact with overhanging brows or protruding pine for pin timbers, or water lines. 5. Contact with persons or collisions with parked equipment. 6. Victims injured by roof falls or falling timbers caused by knocking out roof supports with shuttle cars. 7. Victims injured by runaway shuttle cars. 8. Victims injured while loading or unloading timbers or other materials from shuttle cars. These recurring types of shuttle-car accidents reflect the physical conditions of the working sections, certain safety deficiencies in shuttle-car maintenance and design, and unsafe practices by operators.

Jan 1, 1952

By Paul M. Tyler

Graphite is chemically identical with diamond, both being crystallized allotropic forms of carbon. Graphite obviously differs greatly from diamond in physical properties and is easily recognized by its blackness, its softness (1 to 2 on Mohs' scale), and its slick feel when rubbed between the fingers. Strictly speaking, all graphite is crystalline, but grades in which the individual grains cannot be distinguished with the naked eye are commercially classed as amorphous. Natural mixtures of the two varieties occur in all proportions, and the classification of a given sample as "amorphous" or "crystalline" graphite is based largely upon trade practice. Until recently different varieties of vegetable or animal charcoal, lamp black, soot, gas carbon, and coal ware considered strictly amorphous, but modern examination by X-ray methods indicates that even these materials possess the same internal crystalline structure as graphite, differences in physical properties being perhaps explained by porosity or presence of combined hydrogen or other impurities.

Jan 1, 1941

By Nunna Malakondaiah

Plant samples collected from the mined sites of Beulah, Center and Zap and the test sites of North Beulah 1, North Beulah If, South Beulahh and Center were analyzed for their nutrient concentrations. The vegetation from the mined areas generally showed lower concentrations of Na, P and Cu and failed to meet the nutritional requirements for beef cattle as defined by National Research Council (minimum requirements are: Na, 600; Cu, 4; P, 1800 µg/g dry weight). Plants from Beulah showed generally higher concentrations than from Center or Tap. Tissue concentrations of K varied significantly between sites for 5 species due to the low tissue concentrations at Center. Deficiencies are difficult to isolate as the sampling was done in mid-summer and generally during that season the tissue concentrations tend to decrease in several species. All of the plant species at the unmined sites, with the exception of western wheatgrass at Zap, had lower concentrations of P than the minimum nutritional requirements for beef cattle. Sodium concentration was low but Cu was marginal to adequate in plant species at the unmined sites. Concentrations of K, Mn and Cu in western wheatgrass were greater at Center than at Zap while the opposite was true of the concentrations of Zn, Cu and P in blue grama and Cu in green needlegrass. Amending the spoil with slack at North Beulah I decreased the concentrations of Zn, Cu and P in wheatgrasses grown on spoil from 0-2, 5-10, and 20-25 foot depths, respectively. In general, the mean tissue K+/Na+ ratios were greater in plants on slack amended spoils, primarily due to the reduced Na concentrations in the tissue. At North Beulah II test site, only wheatgrasses grown on spoil amended with slack showed significant increase in K and decrease in Na and Mn concentrations. At South Beulah test site which received 12" topsoil over graded spoil, leonardite amendment decreased P concentrations in all of the grasses as compared to control, whereas fertilizer treatment increased the same. Nutrient concentrations were lower in both fescue and needlegrass with leonardite treatment and higher with fertilizer treatment although not significantly different from control. The concentrations of Ca, Mg, Na, Fe, Cu and N in grasses grown on topsoil at Center test site were significantly higher than on slack amended spoil. Legumes grown on topsoil at Center site contained higher concentrations of P than those grown on spoil; there were no significant effects due to slack on spoil or topsoil. The data presented in this report act only as an indication of between-treatment and between-species differences in tissue composition of plants harvested in mid-summer season. With respect to the nutrients analyzed, since none were found to be toxic, the cattle can safely feed on the vegetation of these mined areas.

Jan 1, 1982

By Leo A. Schrider

A prediction for oil recovery from a pilot waterflood in the Kane oil- field, located in Elk, Forest, and McKean Counties, Pa., was made and compared to actual field performance. Water-injection and production histories, well logs, other field data, and results from laboratory tests of core material were used in this analysis. Performance of the pilot waterflood, initiated in January 1963, was predicted using a modified Craig, Geffen, and Morse calculation technique. Maximum recovery from this low permeable, preferentially oil-wet formation was predicted to be about 22,500 barrels of oil after 300,000 barrels of water had been injected into the pilot waterflood area. After additional field data were collected it became necessary to reevaluate the pilot waterflood area. The gas saturation prior to the waterflood was estimated to have been 20 percent, based on an assumption regarding the required volume of water injected to initiate oil production. In view of the actual field performance, a gas saturation of 13 percent is indicated. When this gas saturation and the method originally proposed by Craig and others are used) the predicted results are more representative. In December 1965, field performance was further analyzed using a hyperbolic-decline curve as presented by Arps. Based upon this evaluation method, the pilot water flood in the Kane sand should produce 37,000 to 42,000 barrels of oil with the injection of 300,000 barrels of water into the pattern. By continuing this secondary-recovery project to a reasonable economic limit, ultimate oil recovery may be as much as 50,000 to 55,000 barrels, or 129 to 142 barrels per acre-foot from 36.5 acres.

Jan 1, 1967

By Corwin L. Cooper

This paper, describing; the milling and cyanidation methods and costs at the Yellow Aster gold mine, is one of a series of papers being prepared by the Bureau of Mines on bold milling practices in the United States. Acknowledgments Acknowledgment is made to the executives of the Anglo American Mining Corporation, Ltd., for permission to publish this article, and to A. W. Frolli, manager, and other members of the company staff, for assistance` in preparing the, paper.

Jan 1, 1936

By B. B. Letson, D. F. Smith, T. E. Gardner, A. R. Taylor

Low- temperature heat capacities of strontium chloride (7° - 300° K) and strontium fluoride ( 11 ° - 300 ° K) were measured with an adiabatic calorimeter . Smooth values of heat capacity , entropy , enthalpy function , and free - energy function were calculated from the heat - capacity data . The smooth values are reported at 10 ° K intervals and at 273.15 ° and 298.15 ° K.

Jan 1, 1963

By Manuel Gomez

The heat contents of thermally dried lignite, subbituminous B coal, and their corresponding low-temperature chars were determined at various temperatures below the highest temperature to which these materials had been exposed before testing. Similar studies were made on high-temperature char and coke, spent shale, and ash prepared from both coal and spent shale. Heat content of the carbonaceous materials tested correlated well with temperature. Heat con-tent results for spent shale compared well with the published results. Statistical analysis of experimental data together with published information showed moisture, volatile matter, carbon content, and temperature to be the principal variables influencing the specific heat of coal. The specific heat of devolatilized carbonaceous substances, char and coke, approached that of graphite as the carbonization temperature was increased. The elemental specific heats of coal constituents, estimated from the ultimate analysis and the specific heat of coal, compared favorably with published elemental specific heats.

Jan 1, 1965

By J. Tomlinson

Shuttle car trailing cable splices were tested for resistance to failure upon being subjected to repeated bending, abrasion, and tensile shocks using a new testing method that closely simulates shuttle car induced stress. The results show that under normal stresses, splices can be made to withstand the equivalent of three months of operational use. Restoring the tensile strength to the conductors is found to be as critical as restoring flexibility. Splices in which the conductors are of slightly unequal length did not present as serious a workmanship problem as previously thought since test results show that the conductors tend to equalize when longer cables, in contrast to short cables employed in previous testing methods, were used. Dynamic recordings of cable tensile stresses are presented for a shuttle car and the new simulated testing method. Two simple but effective methods for removing insulation using a knife and a pair of pliers are described. None of the designs tested for a sacrificial splice covering were satisfactory.

Jan 1, 1979