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Lower the respirable dust exposure of longwall shearer operators by keeping the dust cloud confined to the face. Approach Change the location of face-side machine cooling, water sprays. How It Works The dust breathed by the longwall shearer operator is usually produced by the shearer itself. The dust cloud originates at the face, and the exposure of the operator depends largely on how quickly this cloud spreads into the walkway. Water sprays on the shearer body can have a large effect on dust cloud spreading. Results to date indicate that sprays can help confine the dust cloud to the face if they are carefully placed. Otherwise they can make dust levels far worse. The worst offenders are often face-side sprays used to discharge cooling water from the cooling jackets of the shearer motors. These face-side sprays set up an air circulation pattern as illustrated in the drawing. Air induced by the sprays to flow towards the face, raises the air pressure in front of the face, which causes the air flow to turn and then move back over the shearer, bringing dust with it into the walkway.

Jan 1, 1981

By L. B. Berger, W. P. Yant, R. R. Sayers

"At the request of the Chesapeake & Ohio Railroad Co. a number of tests were made to determine the temperature, humidity, and composition of the atmosphere in certain tunnels of that railroad between Clifton Forge, Va., and Hinton, W. Va. The purpose of these tests was to determine conditions in the cabs of freight locomotives while pulling trains through these tunnels. Tests were made of two types of locomotives, classified by the railroad company as the H-6 and H-7. Both are of the Mallet type, but the H-6 class has one pair of cylinders operating at boiler pressure and the other pair compound, whereas the H-7 operates all four cylinders at boiler pressure, thereby exhausting steam at a higher temperature than the H-6. It was desired to determine the relation between conditions on the H-6 and H-7 engines under comparable conditions of operation. This information supplements previous tests by the Bureau of Mines, discussed in its Reports of Investigations Serial No. 2624, entitled, ""Temperatures in Cabs of Freight Locomotives Passing Through Tunnels of Chesapeake & Ohio Railroad, 11 by s. H. Katz and E. G. Meiter, July, 1924. Three incidental tests of passenger engines were also made."

Feb 1, 1928

By D. E. Wolfson

The Bureau of Mines carbonized 21 coal samples from Fayette, Greene, and Washington Counties, Pa., at 900° C, using the Bureau of Mines-American Gas Association (BM-AGA) method, and determined yields of products and physical properties of the coke. These samples represented high-volatile A Pittsburgh, Sewickley, Waynesburg, and Upper Freeport and medium-volatile Upper Freeport and Lower Kittanning coals. About 20 percent of all coals presently carbonized in commercial coke ovens in the United States are mined in Greene and Washington Counties, principally from the Pittsburgh seam. Sulfur content of the Pittsburgh coals in these counties is moderately high (1.0 to 3.2 percent) but, because of extremely large reserves, accessibility to eastern United States markets and excellent blending characteristics to yield strong coke, these counties will continue to be an important source of metallurgical coals in the future. Most coals from the other seams contained more than 2 percent sulfur, which would limit their use as metallurgical coals.

Jan 1, 1968

By Edward A. Mihok

Laboratory batch-flow tests conducted on a highly ferruginous acid mine water with an activated carbon showed that ferrous iron is rapidly oxidized. This indicates that air oxidation of ferruginous acid in mine waters is catalyzed by activated carbon. The ferrous iron content of an acid mine water flowing through an aspirated activated carbon column was reduced from about 700 to about 10 parts per million in less than 1 minute. Highly efficient ferrous iron oxidation was achieved by conditioning the activated carbon by repeated treatment with acid mine water and air. The reaction proceeds rapidly in the acid environment (pH about 2.5) engendered by ferrous iron oxidation. The activated carbon was used repeatedly with little loss in efficiency, no discoloration, or solids deposition. In these batch tests, about one-third of the iron was adsorbed by the carbon, but with continuous flow, little iron adsorption is expected. Incorporating a catalytic oxidation step in the treatment of acid mine waters containing ferrous iron would greatly facilitate neutralization--precise control of pH, lower reagent costs, elimination of aeration equipment, and smaller holding ponds.

Jan 1, 1969

By E. R. McMillan, M. R. Geer, Joseph Daniels, H. F. Yancey

Investigations of coking properties of Washington coals made before 1939 and studies of coking precesses indicated that PiaTceC:Countyx:oals, particularly those from the Vlilkeson-Carbonado--Fairfax area, yield excellent coke structures. ThE: ash content of the cokes W2S relatively high, sulfur ordinarily.was low, and the phosphorus, although variable, was not excessively high for some purposes. For years the coals had been coked in beehive and standard byproducts ovens and had entered Pacific coast markets for every purpose to which coke is adapted. Certain areas of the Roslyn bed of Kittitas County also were known to possess coals with coking properties. This coal had been employed largely for bench-gas manufacture and occasionally, blended with other coals, in byproduct ovens. Coals from other western Washington areas also had baen utilized for coking in the past but were not of immediate significance.

Aug 1, 1943

By Rad B. Langston, Ted J. Williams, John A. Marjerison, Rimas T. Pakalnis, Tom M. Brady, Doug C. Bayer, Mark J. Bren

Underhand cut and fill mining methods are used at the Lucky Friday, Stillwater, and Galena mines in the western US in an effort to safely mine in difficult ground conditions and as a primary mining method where access below the ore is limited. The method has evolved at each mine to meet the unique situations associated with their milling procedure and mine layout. Details of the operational aspects of the backfilling and mining cycles at each mine are presented in this paper, accompanied by a summary of the mechanical properties of the backfill and its in-situ geomechanical behavior.

By Oliver Bowles

"Waste Granite in the Barre, Vermont, District: Waste in the great granite center at Barre, Vermont, consists of three types of material, the rough blocks rejected at the quarries on account of imperfections, the chips or spalls resulting from trimming and dressing at the cutting plants, and the granular and pulverized material from the dust collectors. The waste piles at the quarries of are immense proportions and constitute a serious handicap to quarrying in that they cover up good rock deposits, and are also so large that waste disposal becomes more and more expensive. The problem of utilization of such waste material is a topic of keen interest to all granite producers.Barre is not situated on a water route, and thus transportation costs prohibit the shipment of waste blocks for rip rap or ballast. Crushing plants use a small amount of this material for road construction, but aside from this, the waste is practically valueless.Investigators of waste utilization problems are awaiting with interest further information concerning an enterprise undertaken at Montpelier, Vermont, to utilize crushed granite for the production of brick similar to sand-lime brick. Granules of granite are mixed with lime, moulded, and hardened under steam Pressure, The brick produced are said to be of excellent quality for structural Purposes.There seems to be no logical reason why waste granite could not be utilized for the manufacture of building stone, and paving blocks, for many of the defects which condemn a stone for monumental purposes are not at all detrimental for building or street paving. F or the most part, monumental stone workers are not particularly interested in other branches of the granite in-dustry, and a combination of industries such as that suggested"

Jan 1, 1920

By L. A. Johnson

This Bureau of Mines report presents the analysis of three cores from the Asphalt Wash area of the P.R. Spring tar sand deposit of northeastern Utah. Two tar sand zones are indicated in the Asphalt Wash Area. Total net thickness of the tar sand ranges from 23 to 39 ft, with occurrences between 56 and 263 ft in depth. The sand has average porosity of 24.7 pct of bulk volume, average permeability before and after extraction of 87.5 and 596 md, respectively, and average oil saturation of 58.1 pct of pore volume. Oil gravity averages 10.9° API.

Jan 1, 1975

By William L. Rice

Geochemical humus sampling techniques were used by the Bureau of Mines in investigating a potential large, low-grade gold deposit in the Orogrande district, Idaho. Conifer needle humus samples were processed by ashing and fire assay-atomic absorption analysis. An area bearing anomalous concentra¬tions of gold and silver was outlined by the geochemical method.

Jan 1, 1970

By Louis D. Dornetto

The effects of electric shocks on man are an important factor in the design of power systems and protective devices. The current levels just below let-go and just prior to the onset of ventricular fibrillation must be known and taken into consideration in the design of power systems and protective devices. Isolated (ungrounded) electrical distribution systems are compared with resistance and solidly grounded systems. The advantages and disadvantages of each are discussed and recommendations are made. Transients on coal mine power systems are a problem that, until recently, have been ignored. Transient voltage levels that can be expected on both the high and low side of the load center and the effects of transients on electronic equipment and personnel are covered.

Jan 1, 1975

By G. W. Murrie, W. P. Diamond, C. M. McCulloch

It is estimated that more than 1 trillion cubic feet of methane is contained within the coals of the Mary Lee group in Jefferson, eastern Tuscaloosa, and southern Walker Counties, Ala. Most of this methane will be encountered by mining. Coals of the Mary Lee group are presently being mined at depths exceeding 1,000 feet and will in the near future be mined at even greater depths, where the problem of methane gas affecting the mining operations will be acute. It is calculated that approximately 90 pct of the methane is at depths greater than 1,000 feet, and over half of the gas is contained within only 12 pct of the study area which is under more than 1,500 feet of over- burden. Degasification in advance of mining will increase mine safety, reduce ventilation expenditures, increase productivity, provide an additional energy source, and make it possible to mine parts of deep coalbeds that probably could not otherwise be mined.

Jan 1, 1976

By R. V. Ramani, V. T. Burgos, J. A. McClay

Cost Systems Cost systems are organized methods of collecting, allocating, and accumulating resource utility expressed in terms of money. There are two major spheres of cost accumulation: financial accounting and cost accounting. Financial accounting deals primarily with historical costs and provides a means of measuring and recording cost events which have al¬ready taken place. While there are no legal requirements to control the methods of recording and reporting cost data in the United States, the procedures in use are guided by professional organizations such as the American Institute of Certified Public Accountants. The final pro¬ducts of financial accounting practices are the income statement and balance sheet which describe the financial status of the organization under study. Cost or managerial accounting is an expansion of financial ac¬counting procedures, providing more detailed cost breakdowns on present operations with one objective being the projection of present costs into the future. The projection process tends to limit the accuracy of the information; however, to management and project justification per¬sonnel, data on future operations tends to be of greater value. The basic principle behind cost accounting is the cost cycle. As products are developed from raw materials, the value of the work-in¬process increases due to the cost input of the various fabricating ele¬ments. Thus, from the basic input elements of facilities, labor, and raw materials, costs are added to each unit of production as a function of the work performed on that unit.

Jan 1, 1975

By Dhaval Patel, Kim Witte, Charles Vaught, Michael T. Stephenson, Steve Booth-Butterfield, Cynthia Zuckerman, Brian L. Quick

This longitudinal field study was designed to encourage Appalachian coal miners in West Virginia and Pennsylvania to engage in hearing-protection behaviors. Method: Participants were mailed postcards that featured either a positive, negative, or neutral message on the outside of the postcard and a message encouraging hearing protection behaviors on the inside. The first posttest measurement of the effectiveness of the persuasive messages was conducted about a week after the postcards were mailed. The delayed posttest measurement was conducted six weeks later. Results: Responses from 307 coal miners revealed that the positive or neutral messages generated significantly more self-reported hearing protection behaviors than the negative message. Identical results were obtained in a delayed posttest assessment of miners' self-reported hearing protection behaviors. The positive message was also more effective than either the neutral or negative message in preventing defensive mechanisms from emerging over time. Impact on Industry: Positive and neutral messages were convincingly more than negative messages in facilitating self-reported hearing protection behaviors among coal miners. Similarly, the positive messages kept defensive processes at bay. Keywords: Hearing protection; Hearing loss; Coal miners; Campaign; Messages

By J. H. Maysilles

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

Jan 1, 1977

By J. H. Perry, Joseph Cervik, G. N. Aul

The Bureau of Mines is conducting research to determine the effectiveness of long holes in degasifying an area of the Upper Split of the Lower Sunnyside coalbed at Kaiser Steel CO.'s Sunnyside No. 1 mine. These holes were drilled from the two outside entries of a section that was closed to mining because of excessive methane emissions. Two holes drilled to 430 and 450 feet produced initial gas flows of 160,000 and 127,000 cfd, respectively. Sixteen days after the completion of the second hole, the total gas production declined to just over 144,000 cfd. In 9 months of degasification, over 35 MMcf of commercial-quality gas has been removed from the coalbed. The combined gas flows declined to 106,000 cfd in the 9-month period. The two holes have reduced face emissions by about 40 pct.

Jan 1, 1978

By Gregory J. Chekan

In order to reduce waste and improve resource conservation, mine planning, and development, the U.S. Bureau of Mines is investigating multiple seam interactions associated with longwall mining. Longwall gate entry and panel stability have been influenced by previous mining in coalbeds above and below a mine in Virginia that operates in the Lower Banner Coalbed. Directly superjacent, approximately 115 ft, the Upper Banner Coalbed has been partially worked by room-and-pillar mining. Directly subjacent, approximately 730 ft, the Tiller Coalbed has been worked by partial room-and-pillar retreat mining. The study mine has experienced problems during development of gate entries in areas of overmining and undermining. It is anticipated that stress fields associated with adjacent mining may further affect gate entry stability and face advancement during the extraction of the longwall panel. To assess overmining and undermining effects on ground stability, the Bureau gathered geotechnical information at the site. Headgate entries and pillars were instrumented and monitored to study loading behavior as the longwall face approached and passed potential problem areas. Measurements indicate that although increases in average pillar pressure were greater than predicted values, previous mining in adjacent coalbeds had little effect on headgate stability.

Jan 1, 1989

By BUREAU OF MINES

The approval of the U. S. Bureau of Mines when granted to a manufacturer for a gas mask is a certification that the particular device has been submitted to the Bureau of Mines for inspection and test and has been found to meet that bureau's published minimum requirements for safety , durability , and satisfactory performance . Any de- Gas masks are approved by the Bureau of Mines only as a complete unit or assembly of parts , as canister , facepiece and harness . This is in order that responsibility for rigid adherence to the bureau's requirements may be definitely located and not divided . vice marketed under this approval must be a unit composed of parts identical in detail of design , assembly , workmanship , and quality , and produced under the same control and inspection as the original device to which approval has been granted . The particular parts which comprise the approved assembly are designated in a letter to the manufacturer at the time the approval is granted . In recent years they are also specified in the approval plate authorized for use in connection with the sale of the device . Each part permitted in the assembly is legibly marked by name or number for the guidance of users of masks in ordering and identifying approved parts when making repairs , and thereby maintaining their equipment as an approved device . In view of the foregoing , any change in the design of parts or deviation from the permitted assembly of parts would violate the conditions under which approval was granted and the device would not be considered as meeting the approval requirements of the Bureau of Mines . The U. S. Bureau of Mines has been frequently requested to interpret the approval status of a gas mask assembled from parts which have separately met its requirements as components of two or more approved devices but which in the form of a complete unit has not been submitted for tests or been granted approval . Responsibility for the elements and for their proper assembly is in such case divided . Such assembled units have no status as permissible equipment under the Bureau of Mines system of schedules . The reasons underlying this policy are that the approval is granted only to some one who assumes responsibility for the whole and that the details of assembly and coordination of parts are considered to be important to the satisfactory performance and safety of the device .

Sep 1, 1932

By F. K. OVITZ

In its endeavor to promote a more efficient use of coal the Bureau of Mines, in cooperation with the Illinois State geological survey and the University of Illinois, has undertaken an investigation of the coking of Illinois coals. The investigation was started by collecting from various sources the data regarding experiments already made by others; these data have been compiled and are presented herein. The present methods of using coal seem wasteful. When coal is burned in furnaces for the generation of steam, only the heat gener- ated by the fuel is utilized; possible by-products are not only lost but frequently are the source of the smoke nuisance. The volatile matter containing the tar and heavy hydrocarbon gases is difficult to burn completely in many furnaces, and its decomposition produces black smoke. When coal is coked in a by-product oven, the volatile matter is no longer a nuisance but, on the contrary, is the source of many by-products, including benzol, toluol, gas, tar, ammonia, and cyano- gen, all of which increase the value that may be obtained from coal. The coke that remains after the volatile matter has been driven off is a valuable fuel that can be used for almost all purposes for which bituminous coal can be used, and it is necessary for some metallurgical work. It has about the same heating value as anthracite coal. Because of its cleanness and its burning without smoke, it is well suited for domestic heating and the generation of steam in plants where smokelessness is demanded. The use of coke for these pur- poses would do much to eliminate smoke in cities. The best grades are regarded as essential in many metallurgical processes for reduc- ing ores to their metals. By-product coking in the United States during the past three years has increased greatly. When the ovens now in course of construction are completed, the total capacity of by-product ovens will be more than double what it was in 1913. This increase has led to a search for coals other than those now known to be available for use in by- product ovens. Tests with coals from the southern part of Illinois have indicated that coke from Illinois coal unmixed with other coals can be used for fuel purposes and that coke from mixtures of Illinois coal with low-volatile coking coal might be suitable for some metal- lurgical work. In the tests the yield of ammonia was larger than is obtained from Eastern coal. Evidently the development of methods by which good coke can be made from Illinois coals and the by-products recovered is a matter of high importance. Any investigation that will indicate how, by proper treatment, these coals can be made available to supply the market for coke and gas in the Middle West will increase efficiency in their use, and will aid in conserving the country's supply of high-grade coking coal.

Jan 1, 1917

By James P. Rider

This U.S. Bureau of Mines report describes a viewing transformation algorithm that generates a perspective view of a three-dimensional scene. This tool may be used by researchers to improve mine safety by assessing the visual capabilities of a mobile equipment operator. Three-dimensional transformations used to build the viewing transformation and techniques used to project the image onto a two-dimensional display screen are defined. The algorithm is written in the C-programming language and designed to stress portability, allowing it to work without significant modifications on numerous computers. A listing of the computer routines along with sample output is included in the report.

Jan 1, 1992

By Henry D. Hibbard

The object of this report is to give briefly information of present value relating to the manufacture and uses of the various commercial alloy steels, with the hope of stimulating the demand for such steels and extending their practical use. The report is issued by the Bureau of Mines as a contribution to the increase of efficiency in the preparation and utilization of the mineral resources of the United States. Alloy steels are included in the so-called special steels, but as the latter term is often used in the mills to designate broadly any steels intended for purposes other than those served by the regular product, it has seemed best to use the more specific term of alloy steels in this report. Alloy steels are bringing about a series of revolutions in various in- dustrial fields in which steel plays an important part. Most elements that could be procured in sufficient quantity have been alloyed with iron in various proportions, either alone or in combination with others, in the search for useful alloy steels. Those steels that have gained and maintained for themselves a place in current use are discussed in this report. Some of them have had an ephemeral life of usefulness which would no doubt have been prolonged had not some other more satisfactory steel been developed. Probably the first useful alloy steel was Mushet's self-hardening tungsten tool steel, patented in 1868. Fifteen years later chromium steel, really containing chromium, was struggling for recognition for some purposes, the chief of which was for the manufacture of solid shot for piercing armor. In both of these steels the effect of the alloying element as used was in a way proportional to the amount contained. In 1882 Hadfield made his epoch-making discovery of manganese steel and demonstrated that in iron metallurgy it is not safe to take for granted anything as to the properties of an alloy of iron with other elements, basing one's opinion on past experience and knowledge, and that the effect of an alloying element may not be proportional to its content. The development of useful nickel

Jan 1, 1915