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Construction workers may be exposed to hazardous dust containing silica when working in enclosed cabs during construction activities. The National Institute for Occupational Safety and Health (NIOSH) found that equipment operator exposure could be reduced by retrofitting air pressurization and filtration systems on existing cabs, using sweeping compounds on soiled floors, and implementing a dust control program.

Jan 1, 2009

By Omotayo Kalejaiye

The Siwek 20-L chamber is widely used throughout the world to evaluate the explosibility of dusts. This research evaluated the quality of dust dispersion in the Siwek 20-L chamber using Pittsburgh coal, Gilsonite, and purple K dusts. A Pittsburgh Research Laboratory (PRL) optical dust probe was used to measure optical transmittance through the dust cloud at various locations within the chamber. A total of 540 tests were performed, with triplicate tests at five nominal dust concentrations and six locations. The two standard dispersion nozzles (rebound and perforated annular nozzle) were compared. The transmissions corresponding to the normal ignition delay period were used to: (a) determine variations in spatial uniformity of dispersion obtained with both nozzles; (b) make comparisons between the experimental transmission data and those calculated from theory for the three dusts; and (c) make comparisons with transmission data measured in the PRL 20-L and Fike 1-m3 dust explosion chambers. The uniformity of dispersion for the three dusts was similar with both nozzles, despite the differences in nozzle geometry and mode of operation. Transmission data of the three dusts were all significantly lower than those calculated from theory. This was discovered to be, in part, due to significant reduction in particle size that occurred during dispersion. By measuring particle sizes before and after dispersion, values of 60%, 50%, and 20% reduction in particle size (based on the surface-weighted mean diameter) were obtained for Pittsburgh coal, Gilsonite, and purple K, respectively. Transmission data from the PRL 20-L, Fike 1-m3 and the Siwek 20-L chambers indicated comparable results in terms of uniformity of dispersion. However, transmission data from the Siwek 20-L chamber were significantly lower than those of the PRL and Fike chambers. Again, this was attributed, in part, to the significant reduction in particle size that occurred during dispersion in the Siwek chamber. The design of the outlet (dispersion) valve of the Siwek 20-L apparatus charge vessel was largely responsible for the particle break-up. The contribution to particle break-up by the dispersion nozzles and the high level of turbulence in the chamber were found to be minimal. This is a significant finding in that the dust particle size tested for explosibility in the Siwek chamber is considerably smaller than the original dust sample.

Jan 1, 2010

By D. L. Bickel

This report presents a Bureau of Mines study intended to determine if horizontal stress trends exist and if the stresses can be projected for improved mine design in a selected coalfield. The horizontal stresses were determined in three mines in the Yampa Coalfield and one mine in the adjacent Danforth Hills Coalfield of northwestern Colorado. Stresses were determined from stress-relief measurements using a three-component borehole deformation gauge and overcoring techniques developed by the Bureau. A least-squares method of calculating the average rock stress components in the horizontal plane was performed. Physical properties of the rock from the test sites are also included. For the Yampa Coalfield, the maximum horizontal compressive stress in the floor ranged from 363 to 1,956 psi, and the maximum horizontal compressive stress in the roof ranged from 235 to 875 psi. For the Dan-forth Hills Coalfield, the maximum horizontal compressive stress in the floor ranged from 360 to 1,494 psi, and the maximum horizontal compres-sive stress in the roof was 1,033 psi. Results indicated a trend of low horizontal stresses in the Yampa Coalfield that have not impacted ground control conditions in mines less than 1,000 ft deep.

Jan 1, 1988

By Peter N. Gabby

In 1990, the Bureau of Mines conducted a mineral resource investigation of the 12.321 acre Black Warrior study area, one of several proposed additions to the Sawtooth Wilderness. No identified mineral resources were delineated. There were 123 lode and placer claims in or adjacent to the study area. There is a known hot spring adjacent to the study area, but presently no geothermal leases are pending. Lode mines in pr adjacent to the Black Warrior study area have produced 4,022 tons of ore from which 1,981 oz of gold and 811 oz of silver were recovered. None of the vines are currently active. During the field study 125 rock samples were taken. Significant gold assays and favorable geologic characteristics at seven properties indicate that gold occurrences and resources with byproduct metals may exist in the study area. Two other sites yielded anomalous gold assays; however, sage favorable geologic characteristics are lacking. Presently, identified gold resources are being delineated by drilling programs in the nearby Atlanta and Rocky Bar mining districts. These districts have geologic characteristics similar to the Black Warrior area. During the field study 22 placer samples were taken. In most places where an anomalous concentration of gold was found, the stream channels are too narrow for operations other than recreational suction dredges. However. One area is estimated to contain over 2 million yd3 of gold-bearing gravels.

Jan 1, 1992

By O. C. Blade

This report on the properties of motor fuels sold through service stations in the United States was made in accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. By agreement with the American Petroleum Institute, identification of the items is confidential. .It presents analytical data for 4, 457 samples, representing the products of 92 companies. The samples were collected by companies during June, July, and August 1956, As in previous surveys, the gasolines covered by this survey include those from both large and small suppliers. The data were obtained by laboratories of various refiners, motor manufacturers, and chemical companies and submitted to the Bureau of Mines for compilation. A list of the National Motor Gasoline Survey reports published during the past 10 years is on page 5.

Jan 1, 1957

By Edwin B. Cook

This report presents the results of calculations of the equilibrium composition of the products of combustion with air of six different mixtures of octane CgH18, plus PbEt4 and halogen-bearing scavengers at three air-fuel ratios, at pressures of 5 and 30 atm., and at temperatures of 350°, 1,000°, 1,800°, and 2,000° K. The air-fuel weight ratio has the values 12, 15:12, and 18. The concentration of PbEt4, M, in milliliters per gallon of iso-octane, has the value 1 or 3. The word "case" is used to designate the halogen concentration. Three cases have been considered [ ]

Jan 1, 1953

By G. C. Branner

The bauxite diagram presented as figure 1 was developed to clarify, by graphic means, the theoretical chemical constituents of gibbsite-kaolinite-type bauxite for all possible proportions of these two minerals from pure gibbsite to pure kaolinite. The tables in the report reflect the same date. The diagram provides (1) a graphic representation of the relations of constituents with respect to a ill possible percentages of alumina and silica, (2) a basis for verifying the accuracy of analyses of gibbsite-kaolinite bauxite, and (3) a basis for estimating the type and proportion of alumina hydrate and/or silicate minerals that may be present in gibbsite-kaolinite-type bauxite. The diagram, with accompanying interpretations and use formulas, will be useful to those connected with the mining and processing of bauxite.

Jan 1, 1955

By J. J. Forbes

Ventilation is the most important safety factor in the production of coal because on it depends the safety, health, and efficiency of those who work underground. Without adequate and efficient means of supplying fresh air to the working faces, mining could not have advanced as it has. The extent of the workings, the increase in mechanization, and the increasing use of electricity are largely responsible for changes in methods of ventialtion. Ventilation in the early, days of coal mining was accomplished by means of a natural draft, created principally by a difference in the weights of columns of air between the intake and return openings: Later the furnace was introduced for the purpose of increasing the quantity of air in circulation. Mines continued to become larger, their output increased, men were employed in greater numbers, and more fresh coal surfaces were exposed. Coal beds near the surface, and practically free from explosive gas became exhausted, and deeper beds that liberated methane were opened as development advanced. Mechanical ventilation became necessary and was first accomplished by disc-type steam driven fans she old-.fashioned steam driven disc fan has generally been supplanted by the powerful electrically operated centrifugal fans in use at modern coal mines. In order to be secure against gas explosions and provide ample fresh air for persons employed in large coal mines, air must be conducted through the mine to all working places and to all other unsealed parts of the mince in sufficient quantities to dilute and render harmless all dangerous and noxious gases.

Jan 1, 1929

By Albert W. Deurbrouck

This Bureau of Mines report describes the washability characteristics of 13 coalbed samples collected in Colorado. Such data are needed to evaluate the quality of the coals of the West, where most of our low-sulfur-content coal reserves are found. Of the 13 samples included in this report, 11 had a total sulfur content of 1 percent or less. All of the samples contained low percentages of ash or could be readily washed to a desirable ash level with minimal loss of yield. The coals ranged in rank from high-volatile A bituminous to subbituminous B; nine of the samples were high-volatile C bituminous. The coalbeds ranged in thickness from 6 to 26 feet; the average was about 8 feet.

Jan 1, 1970

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 Ott F. Heizer

This paper describing the mining practices at the mines of Massachusetts, Massachusetts Co., Inc., at Mill City, Nev., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in tie various mining districts of the United States. The author acknowledges the assistance of William C. Vanderburg, associate mining engineer, U. S. Bureau of Mines, in the preparation of this paper.

Jan 1, 1930

By W. J. Fene, R. D. Currie

The value of protective clothing in the prevention of injuries has long been recognized in many of the leading industries , but the adoption of the idea into mine safety programs is comparatively new . Once started , however , the idea has grown rapidly and the results already obtained by mining companies have shown that it is fundamentally sound . Both coal and metal mining companies are rapidly adopting these protective measures , and since 1924 many mines have become well equipped with eye , head , and foot protection . At the present time approximately 70 percent of the employees in the anthracite mines of Pennsylvania are provided with safety hats . At many metal mines all employees are provided with safety hats, shoes , and goggles . The Pennsylvania mining law provides that all shaft · workers in anthracite mines shall wear protective hats . In According to a study³ made of the nature of 3,485 temporary injuries and of the parts of the body of underground coal mine employees most exposed to occupational hazards , the head and face were injured 665 times , the hands 856 times , and the feet 565 times . Of 2,555 temporary injuries in metal mines , the head and face received 484 , the hands 788 , and the feet 357 . a similar study4 made by a coal -mining company for the year 1928 , of 556 injuries the scalp received 9 , the skull. 4 , the eyes 47 , the hands 62 , the thumbs 21 , the fingers 141 , the ankle , the feet 51 , and the toes 35 . Probably most of these injuries could have been prevented by suitable protective clothing and equipment . This study also revealed that at least one injury occurred

Jun 1, 1933

By P. A. Cox

Guidelines are provided for the design of explosion-proof electrical enclosures that will meet MSHA certification requirements according to Part 18, Title 30, of the Code of Federal Regulations, and fulfill their intended service underground. The guide covers only those aspects of design which affect enclosure strength, ruggedness, endurance and flame path, i. e., the enclosure ability to properly contain an internal explosion. Internal static and explosion pressures, external impact and thermal heating load are treated as well as the proper selection of materials and welding procedures.

Jan 1, 1985

By H. A. Watson

The introduction and use of synthetic materials in various applications may lead to potential hazards from toxic, gaseous, decomposition products if these materials are subjected to conditions abnormal to their intended use, such as high temperatures or burning from accidental causes. This report covers an investigation of such possible hazards from toxic gases produced by the burning or thermal decomposition of some low-density, expanded, synthetic materials, three of which consisted of polyvinylchloride and one of acrylonitrile. In the production of certain expanded plastic materials, Chemical blowing agents frequently are used to produce a cellular structure. One of these blowing or foaming agents contains azo-bis-isobutyronitrile, which is designated in this report as PN. Information indicates that a product of decomposition of this blowing agent, formed in the blowing operation, is tetra-methyl-succino-nitrile, designated as TSN, Which is significantly toxic. Decomposition of the blowing agent, with release of its azo nitrogen, is represented by the following reaction:

Jan 1, 1951

By L. R. Burdick

This paper presents a review of published investigation dealing with the importance of sulfur compounds in the deterioration of materials or providing some basis for estimating the extent of loss shareable to such air pollution. Materials included are cement, stone, metals, paint, leather, paper, sand cloth. The investigations may be divided into two classes, one of the laboratory type in which the sulfur content and the humidity of the air were controlled and the other dealing with the exposure of materials to atmospheres not under control. The first type of work has shown that cement is subject to deterioration by the action of sulfur dioxide gas. The experiments with stone indicate that although limestone takes up sulfur dioxide, from the air, moist sulfur dioxide-air mixtures alone cannot be used for establishing- the comparative weathering- qualities of the different types of stone by accelerated test methods. Laboratory tests indicate that sulfur compounds in the air accelerate the corrosion of iron, steel, zinc, copper, and nickel at normal air temperatures and at certain relative humidities. It has also been indicated that certain types of paint are, affected by high sulfur dioxide concentrations, and that paper is attacked by sulfur dioxide in the atmosphere. The investigations of the second type show the amount or variation of corrosion in different localities and under different types of exposure. The investigations (10) (18)4/ during which sulfur determinations were made indicate that sulfur dioxide is a main controlling factor in the corrosion of iron and steel but according to Quick (18) may not be for some nonferrous metals. In general, the laboratory tests do not Jive definite data on the loss due to sulfur compounds at the concentrations normally found in the air. The data from atmospheric exposures are not complete from the standpoint of the exact effect of the sulfur compounds. Damage to materials so exposed is affected by factors such as other chemical contaminants, humidity, rainfall, solid deposits, and sunlight. A simple scheme has been devised in Great Britain which is considered to provide a measure of the attack of sulfur compound, on building materials (1). Small cylinders coated

Jan 1, 1939

By PAUL L. FISHER

This bibliography has been compiled by the Bureau in answer to many requests now being received for information on the briquetting coal and other carbons . In addition to publications issued by the Government in printed or mimeographed form, references are included to articles appearing in the technical press and in cooperative reports of work done jointly with states , colleges , and industries . References and patents are arranged in chronological order . Bureau of Mines bulletins , technical papers and Minerals Yearbooks are printed , and are obtainable from the Superintendent of Documents ,. Government Printing Office , Washington 25 , D. C. Reports of investigations , information circulars , and the directories and reports of the mineral industry surveys are published in mimeographed form and may be obtained without charge from the Publications Distribution Section , Bureau of Mines , 4800 Forbes Street , Pittsburgh 13 , Pa . Many Bureau of Mines publications , as well as bound copies of the foreign and American scientific and trade periodicals , may be consulted in technical , college , and large public libraries throughout the country. Dealers in new and second-hand books sometimes have copies of these reports for sale .

Jul 1, 1948

By Emory Smith

The preface of the United States Bureau of Mines Manual of First Aid Instruction contains the following paragraphs: One of the most important inquiries that Congress has authorized the Bureau of Mines to conduct relates to health condi- tions among those engaged in the mineral industries. Investigations made early with a view to bettering these conditions demonstrated the need of prompt care of injured miners, as, under the difficulties inherent to mining and other mineral industries; wounds seemingly unimportant, if not treated promptly, may become infected and possibly cause permanent crippling or even death of the porach. In the past many seriously injured persons have been treated by fellow workers ignorant of approved means of treatment and transportation and have been handled in such a manner as to cause suffering and to accentuate injuries to such a degree as to bring about permanent disablement. Accordingly, the need of general instruction in first aid became apparent. It must be recognized that the conditions in and about the mines, mills, smelters, quarries, oil fields, etc., usually present difficulties not found in large industrial centers where experienced surgeons are available and hospitals close at hand. Many mines are isolated and, when an accident occurs several miles underground, there may be a serious lapse of time before the injured person can be brought to the surface and taken to the hospital or given attention by a sur- geon who may have to come a long distance. Under such conditions it has been frequently demonstrated that, if effective first aid is not given, the injured person may die or become permanently crippled... First-aid instruction has been found to be an excellent aid3in pre- venting accidents. In addition to the immediate relief of injured persons, it has been found that most persons while in the act of practicing dressings for

Apr 1, 1931

Early American history is filled with records of the search for and extraction of minerals-a Northwest passage to the treasures of the Indies-an overland route to the goldfields of California. Mining and its associated minerals industry have heralded advancing civilization throughout the ages. The two basic resources on which we all depend for our food, clothing, shelter, and other comforts are agriculture and minerals. Our endowment and how we use it; the spirit and industriousness of our people; our form of social organization all converge to make up our standard of living-our way of life.

Jan 1, 2012

By John F. Papp

International and U.S. chromium material flow, losses, and environmental releases and transfers from mining through industrial processing, end use, and recycling are identified and quantified. Average (1983-92) U.S. consumption has been: metallurgical industry, 87 pct; chemical industry, 10 pet; and refractory industry, 3 pct. Average chromium content of aluminum, cobalt, copper, nickel, and titanium alloys and alloy, carbon, and stainless steel alloys was estimated. Anthropogenic chromium consumption was estimated for the cement and copper industries. N on-commodity cycle anthropogenic chromium mobilization resulting from U.S. fuel and fertilizer use was estimated. Commodity cycle anthropogenic world chromium loss from mining and primary consumer industry was estimated to be equivalent to about 56 pct of chromium contained in chromite ore production and represented a loss rate of 181 kt-Cr/Mt-CrOre. Chromium released to the atmosphere from natural and from anthropogenic sources were comparable in magnitude. Chromium released to soil was mostly from anthropogenic sources, and aquatic releases were all anthropogenic. Domestic product chromium losses exceed process losses by more than a factor of 10 showing the importance and potential environmental impact of post-consumer recycling. The location of historical and current domestic chromium industry processing sites in 23 States were reported. Chromium releases and transfers to the environment were estimated from 1973 through 2002 by primary consumer industry. A decrease in chromium releases and transfers to the environment was anticipated.

Jan 1, 1995

By Bernard M. Larsen, Clyde F. Williams, Edward P. Barrett

"Introduction.The Bureau of Mines at its Northwest Experiment station has been studying the production of sponge iron for the past four years, and during 1923 progress advanced to the point industrial applications can be safely considered. A furnace was operated commercially at silver City, Utah, producing about three tons of sponge iron daily.The Bureau was led to undertake this work by the interest in the use of sponge iron for copper precipitation and for conversion to iron and steel in the electric furnace.If a piece of iron oxide is completely reduced at such a low temperature (850 to 900° C) that no sintering or fusion takes place, then the piece of metallic iron formed has the same size and shape as the original piece of oxide on account of the removal of oxygen, the structure is finely porous, exposing a large surface of iron, and the apparent density is less than that of the original piece of iron oxide. This material is called ""sponge iron"". Chemically, it is a very reactive material."

Nov 1, 1924