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Jan 1, 2012

By ROBERT R. ROUGH, FRANK L. BACON, John Dasher

(being shipped as bailast in ocean freighters). Within the last 10 years it has become more economical to use local sands, and there has been a general shift from the Belgian sand. Deposits of purer sand were treated and used for 'some time: but the suprly became limited, and means were sought to beneficiate the more bountiful subpay-f impure beach sands. These sands are composed of, 50 percent feldspar and 50 percent quartz, with small amounts of iron- bearing minerals, The most objectionable impurities in these West coast sands are the oxides of iron and aluminum. The Del Monte (Calif.) beach sand contains about 0.13 percent FeqQg and about 11.0 percent Aig03 (the latter being furnished by the large amount of feldspar present.) For the manufacture of feldspar present.) For the manufacture of flint-glass containers the maximuni quantities of these two impurities permitted in the sand are 0.05 percent F20 and 6 to 8 percent A1203.. The Fe0g occurs in the sand as follows: Traces of iron-bearing minerais resistant to weathering, ferruginous clay stains on the sand grains, and iron minerais not visible and possibly in solid solution or as colloidal incisions in the grains of feidspar or quartz. A good part of the iron in the sand is present in the traces of iron-bearing minerals, biotite, ilmenite, garnet, monazite; and hornblende. Biotite is present in larger quantities than the others. Samples of quartz, were freed of iron-bearing minerais by the use of heavy liquid (sp.gr. 2.70), leached with boiling HCI and SnCl2. Under a microscope a few apparently clean quartz grains were selected, and Fe203 was determined spectrographically to be 0.03 percent. The technique is similar to that described by Gabriel and Slavin. 4/

Dec 1, 1943

By Henry Kreisinger, WALTER T. RAY

The investigation of the transmission of heat into steam boilers is one of several researches now being carried on by the Bureau of Mines that have for their object the testing of methods by which the mineral fuels in this country may be used more efficiently. A better understanding of the laws governing heat transmission into boilers will result in the design of more efficient boilers, and more efficient boilers will reduce waste in the use of fuel. The results of the investigations described in this report indicate that the conductivity of the heating plates of steam boilers is so high that the present steaming capacities can be tripled or quadrupled by forcing over the heating surfaces three or four times the weight of gases now passed over them. With well-designed mechanical-draft apparatus this greater weight of gases can be forced through the boilers at a small operating cost. It is possible to increase the capacity of many of the present boilers in this way without reducing their efficiency much; in fact by a proper arrangement of the heating surfaces the efficiency can be made higher than the present rating. The efficiency of any boiler can be increased by arranging its heating surfaces in series with respect to the path of hot gases. New boilers of high efficiency can be constructed by making the cross section of the gas passages small in comparison with the length. In Bryan Donkin's book, entitled "The Practical Physics of the Modern Steam Boiler," it is stated that James Watt obtained nearly as good an evaporation per pound of coal and per square foot of heating surface as is obtained now. The remark is probably true. At any rate, about the only decided superiority of the modern steam boilers over older types is in mechanical construction, and for this superiority credit should be given to the designers of machine tools quite as much as to the boiler engineer. The main reason for tardi- ness in boiler improvement probably lies in the reluctance of educated engineers to do the dirty and disagreeable work involved in boiler tests.

Jan 1, 1912

By BUREAU OF MINES

Atentative Draft of a standard smoke abatement ordinance has been prepared by a joint committee made up of representatives of the American Society of Heating and Ventilating Engineers, the Stoler Mamufacturers Association, the American Civic association, and the Fuels Division of the American Society of Mechanical Engineers. The Committee is desirous of obtaining helpful criticism and suggestions about this ordinance, which should be mailed to the chairman, Dr. O. P. Hooi, Bureau of lines, ashington, D. C. Te personnel of the committee is as follows: Dr. O. P. Hood, chairman, and Henry Kreisinger, representing the Fuels Division of the American Society of Mechanical Engineers; P. J. Dougherty, representing the American Society of Heating and Ventilating Engineers; Lloyd R. Stowe, representing the Stoker Mam- facturers Association; Everett L. Hillard, representing the American Civic Ascociation; and Osborn Monnett and Harry 3. Meller, members at large.

Mar 1, 1930

By G. J. Conroy

Cable whip occurring during normal movement of a shuttle car can result in a personnel hazard and excessive tensions in the cable. This Bureau of Mines report discusses preferred payout and reel-in torque settings to reduce cable whip. A simplified adjustment procedure is described.

Jan 1, 1974

By Gary P. Sames

This report discusses some practical applications of a geotechnical investigation conducted by the U.S. Bureau of Mines that can help mine operators meet revised Federal regulations in their roof control plans. The investigation, designed to characterize roof conditions near the coalbed outcrop in drift coal mines in eastern Kentucky, revealed that weathered stress-relief joints near outcrop are crucial ground control factors in the region. The joints' origin and character were determined through underground mapping of many joints in coal mine roof and detailed observations and measurement of joint trends and physical characteristics in widely separated strip mine highwalls and roadcuts. This resulted in an understanding of stress-relief-joint patterns and the effect of various rock types on the intensity of weathering in the joints. That information is used in this report to show how stress-relief joints contribute to roof failure and how, through improved roof support and mine planning, safer roof support plans can be developed.

Jan 1, 1992

This chapter describes the adverse health effects associated with exposure to respirable coal mine dust. Epidemiological studies of underground and surface coal miners in the United States and other countries are discussed. Also discussed are animal studies that add to our understanding of particle deposition and retention in the lungs and associated disease responses. This chapter emphasizes studies that (1) were performed since the passage of the Federal Coal Mine Health and Safety Act of 1969 [P.L. 91- 173], (2) used standardized methods of exposure monitoring and disease classification, and (3) investigated exposure-response relationships between respirable coal mine dust exposure and disease. Several published review articles contain further discussion of health effects studies of coal miners [Attfield and Wagner 1992b; Petsonk and Attfield 1994; Cotes and Steel 1987; Merchant et al. 1986; Morgan and Lapp 1976; Morgan 1975].

Jan 1, 1997

By Henry E. Blake

The purpose of this Bureau of Mines investigation was twofold. The first phase of the work was to determine the technical and mechanical feasibility of defluorinating low-grade siliceous fluorspars on an intermediate scale by high-temperature pyrohydrolysis in a rotary kiln. The second phase was to react the liberated hydrogen fluoride (HF) offgas with alumina monohydrate to produce commercial-grade aluminum fluoride (85 percent AIF3). The two phases of the work were to be integrated into a single continuous process. Evaluation of the data shows that low-grade siliceous fluorspars can be successfully defluorinated, either in a solid or a molten state, in a gas-fired rotary kiln in the presence of water vapor at 1,250° to 1,350° C. The water produced by combustion of propane was sufficient to yield defluorinatians of 75 to 85 percent.

Jan 1, 1962

By I. D. Shah

Thermal decomposition of copper (II) sulfate (CUS04) and copper (II) oxy-sulfate (CuO?CUS04) are important steps in the overall oxidative roasting of covellite (CuS) and chalcocite (Cu2S). Nonisothermal thermogravimetric techniques were used to investigate the decomposition reactions in flowing Na and air. Thermal decomposition of CUS04 and CuO?CUS04 followed "linear" kinetics with an apparent activation energy of 55±2 and 66±3 kcal per mole decomposed, respectively. These apparent activation energies comply with those previously reported when isothermal kinetic techniques were used. The addition of oxygen decreased the rate of decomposition, while small amounts of iron which were admixed with CuO?CUS04 did not have a significant effect. Neither oxygen nor iron had any appreciable effect on the apparent activation energy of the decomposition reaction.

Jan 1, 1972

By Eugene T. Sheridan

This report presents statistical data on individual plants in the fuel- briquet and packaged-fuel industries circularized by the Bureau of Mines, United States Department of the Interior, in its 1957 annual survey. This survey revealed that 17 briquet and 23 packaged-fuel plants were active part or throughout the year. The annual production capacity of the fuel-briquet industry was 3,088,000 net tons, a decrease of 17 percent from 1956. The decline in capacity was caused in part by the permanent retirement of 4 plants and also by the reduction in capacities of 4 other plants. The rate of production of briquet plants also decreased as the industry operated at 35.8 percent of capacity compared with 40.9 percent in 1956. Every operating plant in 1957 had an annual capacity exceeding 25,000 tons.

Jan 1, 1958

By J. T. Schimmel

The purpose of this investigation was to obtain complete information on some of the uses of a 24-inch-diameter auger in the underground mining of pitching anthracite beds. The auger was placed in operation early in 1958 to drive ventilation connections between coal gangways driven by a continuous miner. Although designed to drill rise holes only, it was used also to drill dip holes. The latter holes were drill id from an adjacent gangway to avoid interference between the auger and the continuous miner. These holes established immediate ventilation returns when intersected by the continuous miner. Bureau participation in the project covered 361 working days. The auger was used on 288 shifts, usually one 7-hour shift per day, and drilled 3,246 feet, of which 493 feet were reamed. The longest hole was 87 feet; hence the maximum drilling depth of the machine (rated at 100 feet) was not required. Holes drilled normal to the strike of the bed ranged from 30 to 66 feet deep, averaging 45 feet. The continuous miner drove gangways on 575 shifts. Thus, the auger worked one shift for each two worked by the continuous miner and was used on less than 80 percent of the workdays. The auger drove 24-inch holes 10 times faster than the larger, conventional openings could have been driven by usual mining methods and exceeded the workload for which it was purchased. Augering eliminates exposure to the hazards encountered in driving chute-work by conventional methods and provides adequate circular ventilation openings, which are strong in self support and are adaptable to reaming when required. With alterations, the auger may have limited use as a production machine in thin-bed pitch mining but cannot compete with established methods of thick-bed pitch mining.

Jan 1, 1962

By R. A. Keaens, L. C. IlsLey

For the purpose of this paper a junction box is defined as " a fused switch, inclosed in an explosion-proof compartment, provided with a ready means of connecting or disconnecting a trailing cable without exterior arcing." Junction boxes are intended for use 'at the end of trailing cables and are usually placed outby the last open break through in a coal mine. Where it is not safe to supply current through nips or a trolley, junction boxes suitably spaced along an entry permit tramming and movement of machines with safety, although not with any considerable speed. Junction boxes serve a threefold purpose: (1) They prevent dangerous arcing at the outby end of trailing cables; (2) they afford a safe, practical means of fusing or otherwise protecting the trailing cable; and (3) they provide an efficient means of transmitting power from the power circuit to the trailing cable. The first purpose is the most important from a safety standpoint. Dangerous arcing-that is, arcing capable of igniting gas-frequently takes place where trailing cab1c.s are attached to the power circuit. At either 250 or 500 volts only a very small arc is required to ignite mine gas. The usual method of connecting the trailing cable to the power circuit by cable nips or trolley taps does not make a good electrical connection; hence arcing may be expected at any time. Furthermore, junction boxes eliminate the personal hazard attendant upon the use of trolley taps by removing the possibility of accidental contact with trolley hooks or wire and the liability to injury due to manipulation of the device. In the general scheme of mine ventilation it is assumed that gas will not accumulate where junction boxes are placed, an assumption based on the normal operation of the ventilating system. In many

Jan 1, 1929

By BUREAU OF MINES

The Bureau of Mines, in its investigations of respiratory apparatus for use in mines and allied industries; tests equipment that is voluntarily submitted by manufacturers in accordance with published schedules of tests. These tests are designed to insure that the equipment has the minimum requirements for safety in use. Approval certificates are issued for apperatus that meets the bureau's specifications, and the manufacturer is permitted to mark his equiment with a seal showing that it has been approved as "Permissible." A complete list of per- missible self-contained oxygen breathing apparatus, gas masks, and hose masks tested prior to January 1, 1930, was published in Bureau of Mines Information Circular 62309. The present list includes all equipment tested and approved prior to July 1, 1930.

Sep 1, 1930

Only limited work has been reported in the literature about the use of latex in soil. Unisol 91 2,3 (a 9:l oil-latex emulsion made b International Synthetic Rubber Company) and Phil1ips Petroset4 geotechnic emulsions are surface soil stabilizers which penetrate a maximum of two inches, but do not reduce permeability. Diamond Alkali 5 found that styrene-butadiene rubber latex as a one percent latex-soil mixture reduced permeability to 0.7 from 21 feet per year under a head of twenty feet of brine. We have found no literature reference for use of latex as sealant at depth in the soil, although asphalt has been applied at depth using civil engineering methods6,7. Most of the materials investigated as soil sealants in the present work were latexes, although some studies were also conducted with a variety of inorganic and organic chemicals. Of the latexes tested, most were rubber but a few were plastic, e.g. polyvinyl chloride. Sealants examined in this investigation are listed individually in Table I with supplier, code number, and other pertinent information. The materials consisted of the following general classes with additional details as indicated: 1.Anionic latexes: a. styrene-butadiene copolymers and terpolymers (SBR) b. butadiene-acrylonitrile copolymer (Paracrils®) c. polyvinyl chloride homopolymers and copolymers (WC) d. ethylene-propylene terpolymer e. vinyl acetate homopolymers and copolymers (VA) f. acrylics (acrylate copolymers) g. 2-chlorobutadiene homopolymer (chloroprene) (prepared specially as cationic material coagulated by soil). 2. Water Soluble polymers: a. polyvinyl ether b. methylcellulose c. polyethyleneimines d. polyacrylic acid homopolymer e. copolymers and terpolymers with acrylic acid types (water soluble as sodium or ammonium salts) f. alginates g. monomers (for polymerization in soil, e.g. acrylamide)

Jan 1, 1972

By R. V. Ramani, A. S. C. Owili-eger

The Federal Coal Mine Health and Safety Act of 1969 (sec. 303 (b)) stipulates that no working section of the mine shall contain more than 0.5 percent carbon dioxide and no harmful quantities of other noxious or poisonous gases such as the oxides of nitrogen. The concentration of methane should at all times be maintained below one percent. A split of air returning from any working section shall contain no more than 1.5 percent of methane (sec. 303 (i) (2)) and air that has passed by an opening of any abandoned area shall not be used to ventilate any working place in the coal mine if such air contains more than 0.25 percent of methane (sec. 303 (j)). Methane concentration in the returns from the bleeder entries should not exceed 2.0 percent (sec. 303 (i) (3)), and no air that has passed through an opening which is inaccessible for examination shall be used to ventilate any active areas. While the air quantity requirements alone can easily be met, the governing condition in most mines is the dilution requirements for quality control. A sufficient quantity of air is required to render harmless and carry away noxious and respirable pollutants. In recent years, changes in coal extraction methods, rates of advance, location of available reserves, position of prominent methane sources and horizons, and geological sequences have contributed sig¬nificantly to alterations in rates, patterns and character of numerous methane emissions. Gas production of 10 to 15 million standard cubic feet per day is not uncommon from deep mines (Cervik, 1969). Thus, because of the large capital outlay involved in the instal¬lation and subsequent remedial actions of methane drainage systems, knowledge of gaseous flow patterns and storage characteristics of the

Jan 1, 1974

By J. P. Barkley

"The accompanying tabulation gives the results of a series of operating tests on two types of small stokers. One was an inclined, natural-draft, moving-grate, overfeed ""hand-stoker"" fired and manipulated by hand; the other was. a horizontal, forced-draft, stationary-grate, underfeed, mechanical unit-stoker operated by an electric motor. These were installed as shown by the accompanying sketches (figs. 1 and 2) under horizontal return tubular boilers of a nominal rating of 150 bl.h.p. each.The steam load carried by these boilers was a rather typical heating load. It was fairly constant and of about 30 bl.h.p. throughout the summer months, with small variation between day and night. During the winter months the daily variations were dependent upon the outside temperature. The boilers were banked a considerable part of the night.As noted in the table, two kinds of coal were used. The size of one kind was run-of-mine and the other 11/4 inch nut and clack. These coals from two different mines of the New River district both caked considerably during burning, the nut and slack more than the other. Analyses of the coal were as follows:"

Jun 1, 1929

By Gerald T. Homce, Michael R. Yenchek, H. Kenneth Sacks, James C. Cawley

Accidents occur when least expected, from sources that we rarely anticipate and with outcomes that can vary greatly. Anyone who has ever been involved in an automobile accident knows, the transition from driving comfortably and safely down a highway to being involved in a potentially life-threatening situation can occur in a heartbeat. Accidents on the job are no different. The mining industry has a relatively small number of electrical injuries, compared to industries such as construction or agriculture, due to the small total employment in mining. Mining does, however, have one of the highest occupational electrocution rates of any U.S. industry, at 2.8 for every 100,000 workers per year. This is approximately four times the average for all industries. Data from the Mine Safety and Health Administration (MSHA) shows that 75 electrical fatalities occurred in the mining industry between 1990 and 1999. Of these, at least 17% involved high-reaching mobile equipment that contacted overhead power lines.

By E. P. Youngman

The mining law of the Belgian Congo does not cover the Province of Katanga nor the District of Kivu (in Eastern Province). Regulations of the Comité Spécial du K tanga are in force in Katanga and those of the Comité National du Kivu in Kivu. The three laws differ only in detail, and grants made by the Comité Spécial du Katanga or by the Comité National du Kivu must be approved by the Ministry of Colonies. The following résumé is designed to coordinate the three sets of regulations.

May 1, 1930

By Rudolf Kudlich

"During the coming winter, it is probable that many householders who have habitually been users of anthracite coal will be obliged to turn to some other fuel for heating purposes, because of the limited supply of anthracite. The next best fuel, from a standpoint of cleanliness and ease of operation, is coke, but here again the supply is inadequate and the householder will have to fall back on bituminous coal. Though bituminous coal has the dis¬advantage of being dirty to handle, requiring more care in firing, and of giving off considerable smoke, it will be more generally available, costs less, and in the better grades which will naturally find their way to the domestic market, is higher in heat value, and contains less ash than anthracite.Choice of CoalThere a variety of bituminous coals are available, the householder should choose a low volatile coal, such as New River, Pocahontas, or some other ""smokeless"" coal, or the British coal now being offered in the markets along the Atlantic seaboard. Though not necessary to have the coal sized, as is the case with anthracite, it will be found cleaner to use coal from which the fine dirt has been screened. If it is found that excessive dust is caused when firing the coal, this can be reduced by slightly wetting the coal at the front of the bin, as it is being used.Method of Firingusing bituminous coal instead of anthracite in the domestic furnace, it will be necessary to use an entirely different method of fir Instead of leveling the fuel bed and putting on fresh coal in an even layer over the entire fire box, the coked and partly burned coal remaining from the previous firing should be pushed as much as possible to one side of the box, and the fresh coal thrown into the empty side so as to leave some burning coal exposed. In this way the green coal is heated slowly, the volatile gases are given off gradually, and are ignited by the burninggoing to waste up the chimney unburned."

Oct 1, 1922

By L. C. IlsLey, R. A. Kearns

As the use of electricity becomes more and more general in mining opera- tions, interest in regulations governing its application becomes greater. During the past year the electrical section of the Bureau of Mines has made a study of State regulations now in force relating to the use of electricity in coal mines. Technical Paper 271, entitled "State Mining Laws on the Use of Electricity in and about Coal Mines", has been published as a result of this study. The present paper represents a compilation of all laws relating to accident prevention with respect to electrical circuits. This group of regulations is perhaps the most important of any that relate to safety in coal mines. Its importance is shown by reference to accident statistics in Bulletin 115, (Fay, A.H., Coal-Mine Fatalities in United States, 1870-1914, Bureau of Mines, 1916), which show that about 77 per cent of the fatalities due to electricity in and about coal mines were caused by direct or indirect contact with trolley or other power circuits. In actual number this means that of 710 men killed by electricity, 546 were killed by contact with electric wires. Undoubtedly, a large percentage of these accidents might have been prevented had the wires been properly guarded. The compilation follows:

Mar 1, 1921