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By N. S. Dalal, X. Shi

"With a view of elucidating the role of glutathione (GSH) in the biochemical pathways of the chromate-exposure related carcinogenesis, we carried out electron spin resonance (ESR) spectroscopic investigations of the chromate-GSH redox reactions. The ESR measurements, employing spin-traps, provide evidence for the involvement of the glutathione (GS•) radical, as well as an isolable Cr(V)-glutathione intermediate. These results indicater a new mechanism for the reduction of chromate by GSH in cellular environment and help understand the (unexpected increase in Cr(VI)-induced DNA strand breaks at elevated GSH levels.We report here indirect electron spin resonance (EGR evidence for the involvement of the glutathionyl (GS) radical and direct evidence for a Cr(V) intermediate in the reactions of glutathione ¬(GSH) with chromate for the first time.. This work was undertaken to clarify the biochemical pathway of the reduction of chromate by GSH, since this reduction process is thought to be a critical step in the pathogenesis of the chromate-exposure related carcinogenesis. This follows from the literature reports which show that (a) Cr(VI)compounds have been proven to be carcinogens in laboratory animals as well as in human studies2-4, (b) Cr(VI) and not Cr(III) compounds are mutagenic 5-7, (c) Cr(VI) and not Cr(III) compounds can penetrate cell membranes 8.9 (d) the final state of Cr(VI) in cellular reductions is Cr(III)', (e) by itself chromate (or Cr(VI)) cannot be directly mutagenic since Cr(VI) is known not to interact with isolated DNA under physiological conditions 10, suggesting the significance of Cr(VI).reduction processes. One of the major reductants in cellular environments is thought to be the GSH, both outside and inside the ce11s 11-13. Other evidence for the role of GSH in the chromate toxicity is seen from recent studies showing that exposure of hamster cells to non-toxic levels of added selenite increases the levels' of GSH as well as the Cr(VI)-induced DNA strand beaks 14, and thatsuch DNA strand breaks in hepatocytes also change in direct proportion to their GSH content 15,16. These observations wereinterpreted as implying that the reduction of chromate by GSH, to some reactive intermediate is an important step in the chromatecarcinogenicity 15,16. The following reaction steps were,suggested 15, 16"

Jan 1, 1988

By J. A. Holmes

As part of its investigation of methods of increasing the efficiency of fuel resources, the Bureau of Mines is continuing the study of the general problems involved in the economic use of fuels in gas pro- ducers that were carried on by the technologic branch of the United States Geological Survey. In the course of this study many inci- dental problems of prime importance have demanded consideration. Among them is the determination, under practically constant con- ditions, of the duration of gas-producer tests necessary to reduce the possible error to a minimum. A discussion of this proper length of test period forms the first part of this bulletin. An attempt to dispel some of the uncertainties that arise in an investigation or to account for some of the minor phenomena often necessitates a systematic and careful study of certain chemical, ther- modynamic, or physical laws, or a combination of these, which in turn may result in information or conclusions of great value. Fur- thermore, seemingly unimportant observations often prove to bear directly upon the design, construction, or manipulation of the machine under test. In attempts to improve the gas producer considerable attention has been given by manufacturers to such questions as fixing or isolating the combustible components of the tar, utilizing the waste heat of the producer for the generation of the steam required by the plant, apply- ing the suction principle to bituminous coal and other tarry fuels, and many allied subjects. Little study, apparently, has been given to the physical-chemical conditions most suitable to the formation of hydro- gen and of carbon monoxide, with a view to regulating the percentages of these gases in generators using fuels other than anthracite coal or charcoal. An attempt was made to introduce such investigations when the operations of the government coal-testing plant began at the Louisi- ana Purchase Exposition in St. Louis in 1904, but owing to adverse conditions these problems were abandoned until the plant was trans- ferred to Norfolk in 1907. The delay in beginning this line of inves- tigations, together with the short testing season at Norfolk, limit the second part of this report to preliminary physical-chemical studies, which, however, were sufficiently significant to warrant careful ex- amination pending more complete researches, which are being carried on at the station located in Pittsburg.

Jan 1, 1911

By D. Harringtong

"There has been much writing and argument on the subject of giving bonuses to miners, quarrymen, metallurgical and chemical workers, and others as a stimulus for safe work and for work safely done. Theoretically, everyone should be careful and should not need monetary or any other type of encouragement for the prevention of accidents; as a. fact, few people are careful, and this is primarily the reason way many if not most accidents occur. A bonus, however, is not simply money given away by an employer; it must be earned, so to speak, before it becomes due; in other words, if the standard established is not reached, no bonus is paid, and in many cases some disciplinary action is taken.The United States Bureau of Mines Is asked from time to time for suggestions for rewards to mine workers who have a good attitude toward working safely or who need some stimulus to cause them to make greater or more earnest efforts toward safety for themselves and their co-workers. A recent inquiry prompted the collection of data on some safety bonus systems from reports of this bureau's field engineers and others, and some of these Now given. Bonus practice at both coal and metal mines is included because a system used at metal mines is generally adaptable to coal mines; in fact, in numerous cases, bonus systems recently started at some coal mines are based on systems in vogue and giving satisfaction some metal mines; in-some instances, also, metal mines have been able to get good suggestions from coal mines or from the cement or petroleum industries. it .should be understood that a bonus, even as applied to the encouragement of safety, does not necessarily mean payment of money; in fact, some successful bonus systems have in them no direct money exchange; hence, the bonus as treated in this paper is that defined as ""Something given in addition to what is ordinarily received by, or strictly due to, the recipient.""Acknowledgment is given here to members of the safety division of the Bureau of Mines who sent in some of the information here presented; to the Engineering and Mining Journal and Mining Congress Journal, from which some items were abstracted; to various mining officials who gave data in one form or another; and to M. von Bernewitz, of the United. States Bureau of lines who aided in framing parts of this paper."

Jun 1, 1932

By Paul T. Allsman

THIS CHAPTER reviews the highlights of developments in mining technology during 1956 and presents a special report on the design of mine openings in stable ground. This special report is presented each year in an endeavor to stimulate use of the scientific approach to the solution of problems related to mining technology. Assuming that the literature on mining technology reflects trends in mining, it appears that two areas of activity were given most attention in 1956. One was research on mining technology,4 and the other was improvement of transportation, particularly trackless transportation, both at surface and underground mines.

Jan 1, 1958

Roof screening for ground control originated with metal miners in the western United States. At first chain-link fence was used, but because it was so difficult to handle, the miners started installing a more rigid welded wire screen used in the concrete industry. Eventually coal mines in the west began to use screen, and now more and more coal operations, especially longwall mines, are installing roof screen on a regular basis. Screen use has recently increased in the Illinois basin and is now making its way to underground coal mines in the eastern U.S.

By David A. Lipton

In 1980, the U.S. Bureau of Mines conducted a mineral survey of the 23,500 acre Garcia Mountain RARE II area (No. 5107) in the Los Padres National Forest. Bureau of Mines data indicate a low potential fur gold, silver, and mercury resources. Twenty-nine placer samples, representative of small yardages, showed small amounts of gold or other economic mineral values. Mercury deposits in faulted siliceous rocks in the Franciscan Formation occur north of the area. Similar rocks are in the southwest part of the study area, but apparently contain no mercury deposits. Geothermal and oil and gas potential is low.

Jan 1, 1982

By A. J. Barry

Recent developments in mechanizing longwall it mining in Europe have aroused considerable interest among American coal-mine operators because this method provides an opportunity to improve safety, production, efficiency, and recovery. The success of longwall mining in Europe has depended to a large degree on development of effective roof-control systems. One of the major contributing factors in designing these systems is development off improved supports, which combine high load-bearing capacities with controlled yield characteristics, to use in the face areas. Other factors that relate to successful longwall mining involve knowledge of the structural properties of the strata above end below the coal bed being mined, movements of these strata induced by mining, and effects of the strata movements on the strata itself, as well as on the support system used. Extensive studies of the above factors relating to long-wall mining have been made in coal-mining countries abroad, and corresponding studies (1, 2, 3, 4, 5)3/ of room-and-pillar operations have been made in this country. Although descriptions and results of experiments of mechanized longwall operations in the United States have been published (6, 7, 8), this is the first instrumented study of roof behavior on a longwall operation. In view of the possible widespread application of this method of mining to American coal mines, where underground mining conditions are different from those found in European mines, an investigation was conducted at a mechanized longwall operation inn the Lancashire No. 15 mine, Barnes & Tucker Co., Cambric County, Bakerton, Pa., to study the factors that affect roof control. This report describes this investigation and discusses the results. ACKNOWLEDGMENTS This investigation was made under a cooperative agreement between the Bureau of Mines and the Barnes & Tucker Co., Barnesboro, Pa., end was conducted in the Lancashire No. 15 mine located at Bakerton, Cambria County, Pa. The authors acknowledge the cooperation given by Richard Z. Todhunter, Sr., president, Richard T. Todhunter, Jr., general manager, and other mine officials and employees of the Barnes & Tucker Co. Mr. Edward Thomas, chief, Roof Control Section, Bureau of Mines, Washington, D. C., and Dr. Leonard Obert, chief, Applied Physics Branch. College Park, Md., collaborated in the planning and promulgation of the program investigation.

Jan 1, 1954

By W. T. Culler

"The ""rate-of-preduotion curve"" described in the revised Treasury Manual* was devised by the author in May, 1920, and since that time has been use by the oil and gas valuation section of the Treasury Department in determining the rate of production of wells for purposes of taxation. This curve is most useful for estimating the future production of a well, or group of wells, of known daily settled production, where future-production curves and tables based on yearly production records are available. It also provides a means for determining the past year's production of a well of known daily settled production, or conversely, the estimated production on any day for a well of known yearly production.The rate-of-production curve is auxiliary to the production decline curve and is derived from it in estimating the future production of a tract, a production decline curve formed from the records of the tract itself should be used. If such records are not available, and there is no information which leads to the belief that the average production decline of the wells in this tract differs from the average for the pool or district, an average curve for the pool or district may be used.The accompanying chart illustrates a typical rate-of-production curve, with the yearly production decline curve from which it is derived. The production decline curve shown is for an average well in the Augusta district, Butler County, Kansas, and has been constructed from the tables given on page 128 of the revised Treasury Manual.The ordinate (vertical scale on the chart) of any point on a yearly production decline curve represents the production of the well during the year previous to the date shown by the abscissa (horizontal scale). For example, the chart shows that an average well, which produced 100,000 barrels of oil in 1915. produced 92,000 barrels in the year previous to January 19, 1916, produced 53,300 barrels in the year previous to June 1, 1916; produced 49,000 barrels in the year previous to July 1, 1916, 27,000 barrels in 1916, and 10,000 barrels in 1917."

Oct 1, 1921

"A coordinated, integrated research effort aimed at studying the scientific, engineering and medical aspects of the respirable dust problem is underway in the areas of dust generation, dust dispersion and dilution, dust characterization, interaction of dust and lungs, and relationship of seam characteristics to dust generation and mobility. (FIGURE 24) The Center's research program explores these concerns with the objective of refining existing strategies and developing new respirable dust control techniques that are consistent with the dust-lung interaction processes that lead to mine worker disability. The fundamental aspects of this work are applicable to the control of respirable dust problems in both hard rock mines and coal mines and to other dusts such as diesel-generated.Research projects in the Generic Mineral Technology Center for Respirable Dust have effected several improved methods for the preparation and characterization of the dusts needed by these projects. Superior procedures for generating ""standard"" dust samples have been developed and are in regular use in the laboratory. Questions raised during the course of some projects regarding ""stale"" versus ""fresh"" dust have led to the development of sampling techniques where the dust is directly collected in a surfactant. MSHA and CANMET have requested and received information on Center generated software. An equipment manufacturer, TSI, Inc., requesting input on modifying the inlet of an aerosol sampler has been assisted as a result of research that was conducted at the University of Minnesota.The objectives, scope and progress of all the research projects in the Center, in the form of abstracts and reports, have been detailed in Volume 1 of this series. Research papers written by the principle investigators and resulting from the findings of projects (FIGURE 25) and which are funded by U.S. Bureau of Mines grant number G1135142 have been published in Volumes 3 through 6 and Volume 8 of this series. Volume 2 relates the cooperation and interaction of the U.S. Bureau of Mines and the Generic Mineral Technology Center for Respirable Dust in research on the problem of respirable dust in the mineral industries."

Aug 31, 1989

By D. W. Bridges

Solvent extraction has become important in recent years as a unit process in extractive metallurgy. The flexibility and simplicity of the technique have attracted widespread attention, and numerous papers describing actual and projected metallurgical applications have been published. However, differences in terminology, procedure, objectives, and standards, as reflected in reports by different operators and investigators, have sometimes made appraisals and comparisons difficult. Consequently, a need appeared for n series of basic reports on the subject. This Bureau of Mines Information Circular is the first of such a series. It deals with the status of solvent extraction in metallurgy, as well as with the rudiments and terminology of the unit operation. In analytical chemistry, extraction of molecular species from aqueous media by immiscible organic solvents has been used for many years to separate and determine chemical elements (61).4 Complex chlorides of iron and other metals are readily soluble in ethers and ketones, as are the nitrates of uranium and thorium. Most metals are extractable as complex salts of some organic reagent, such as dithizone, 8-hydroxyquinoline, or cupferron.

Jan 1, 1962

By Irving Hartmann

When permissible explosives are used in coal mines according to the procedure recommended by the Bureau of Mines they are relatively safe, and no mine explosions are known to have resulted from this type of blasting. However, unsafe blasting practices - the use of nonpermissible explosives or the improper use of permissible explosives - have caused many serious disasters. In fact, such unsafe practices constitute the third most important cause (exceeded only by electricity and the use of open lights and smoking) of coal-mine explosions in the United States. During 1929-1947, inclusive, 81 explosions, resulting in 475 fatalities, were ascribed to unsafe blasting. The hazards of black powder, dynamite, and other nonpermissible explosives in coal mines have been recognized for many years, and attention has been called to this in numerous Bureau of Mines publications. Not only can these explosives ignite namable gas-air mixtures readily, but they can also ignite coal dust, as has been illustrated repeatedly in tests and at educational public demonstrations at Bruceton and elsewhere.

Jan 1, 1952

By Bruce D. Hanson

The Bureau of Mines conducted a series of ignition tests with two types of conical bits (plumb bob and pencil) used on continuous mining machines, to determine their ignition potential at various bit speeds, cut depths, and wear conditions. The tests were conducted using single bits mounted on a 34-in-diam drum in a Bureau ignition test facility. The bits impacted blocks of Berea sandstone in a 6.5 pet methane atmosphere at various bit speeds and cut depths. In a new condition, the plumb bob bits were considerably more incendive than the pencil bits, causing ignitions in 32 of 35 tests at 60 rpm, compared with ignitiolls in 2 of 22 tests for the pencil bits. The results from new bit testing also show that reduction of bit tip velocity to 180 fpm does not eliminate ignition potential. When subjected to progressive wear, bits of both types were more incendive when they were locked in place, unable to rotate, than when they were free to rotate.

Jan 1, 1983

By C. C. Furnas

Despite the fact that a great many industrial processes depend on efficient contact between a gas stream and a bed of broken solids for their operation, the data in the literature are very meager. Several investigations3 have been undertaken, but the work has been limited in scope and application. BUREAU OF MINES PROGRAM OF RESEARCH For the past 10 years the United States Bureau of Mines has been engaged in research with the object of formulating a more or less complete quantitative theory of the workings of the iron blast furnace. Obviously, in order to do this one of the essentials is to have considerable definite information on the laws of gas flow through beds of broken solids. This report in a brief summary of the experimental work on the problem which has been done at the North Central Experiment Station. The complete report with more detailed tabulation of the data and explanations of the experimental procedure is in process of publication in the form of a bulletin.

Jan 1, 1928

By M. M. Wong, J. E. Klosterman

Scrap beryllium chips ( nominally 96 to 97 percent Be ) were electrore fined in a prototype cell with 408 lb of electrolyte composed of 52.4 mole - percent LiCl , 36.3 mole - percent KC1 , and 11.3 mole - percent BeCl2 . The cell temperature was 500 ° C. In a typical 10-3 /4 - hour deposition cycle , 0.415 pound of metal was produced ; the metal contained impurities in parts per million as follows : C , 700 ; 0 , 610 ; Al , 34 ; Ca , 32 ; Cu , 20 ; Fe , 25 ; Mg , 9 ; and Mn , 23 . Operation of the prototype cell for 2 years demonstrated that adapting the electrorefining process to an enlarged scale of operation presented few difficulties in mechanical functions , maintenance of optimum operating conditions , and control of product purity . After the spent anode feed was leached in a 5 - percent nitric acid solution and the fine - sized particles were removed , it was recycled in some tests . The metal produced was somewhat higher in impurities than metal from the fresh scrap chips .

Jan 1, 1964

By Byron M. Bird, Earl R. McMillan

"The method and apparatus described herein was developed at the Northwest experiment station of the Bureau of Mines, Interior Department, in cooperative research work with the University of Washington. A fuller description will appear in a bulletin entitled ""study of coal washing problems in the Pacific Northwest, to be published by the University. During the past four years this Bureau and the University have been co-operating with various coal companies in the Pacific Northwest in an extensive study of coal washing problems. Much of the valuable data resulting from this study has been obtained with the well-known float-and-sink test. This test has known for a number of years****, but its possibilities have not been thoroughly understood. A few investigations have developed apparatus and technique suitable to their needs, but these were not adopted to the conditions faced in the Northwest. Thus, the necessity arose for designing suitably equipment and working out a method of procedure or technique in carrying on the fundamental studies of coal washing by means of the float-and-sink test method."

Feb 1, 1924

By R. D. Eash

The purpose of this research contract was to develop and test a Saran latex modified portland cement concrete lagging to be used as a replacement for wood lagging. The scope of work performed was divided into four phases: Phase I - Engineering Criteria; Phase-! I1 - Design Study; Phase III - Fabrication of Lagging; and Phase IV - Prototype Demonstration Project. Each phase of work was completed and is described in detail in this report. The prototype latex modified concrete lagging developed in this program weighed 52 pounds. When tested in flexure, it supported center point loading of 4500 pounds and under 1/4 point loading it supported loadings of 7000 pounds. Deflections at maximum loading ranged from 1/2 to 1 inch. Maximum deflections exceed 2 inches. The lagging does not exhibit catastrophic failure. Two hundred and twenty of the LMC lagging were produced and shipped to the Bunker Hill Company in Kellogg, Idaho for installation in their mine at the 17 level. The lagging are performing satisfactory after 22 months exposure in the mine.

Jan 1, 1980

By Jack Mantel

The goal of this 42-month contract was to increase safety in low-seam underground coal mines through development and in-mine evaluation of a temporary roof support system for roof drills and floor-riding operator compartments for a loader and shuttle car. The program was performed in three phases. During Phase I, state-of-the-art canopy technology was investigated, and preliminary design and mock-up evaluations were performed for temporary roof supports for single-and dual-boom bolters and for transverse-mounted floor-riding canopies for a shuttle car and coal loading machine. The shuttle car and loader canopies were approved for further development, and the design, fabrication, testing, and certification were completed in Phase II. In Phase III, the Bureau of Mines furnished an FMC 6L shuttle car fur use in the evaluation of the canopy for 45 shifts. The shuttle car canopy was evaluated at Virginia Crews Coal Company in West Virginia. Efforts to secure an evaluation site for the loader canopy were unsuccessful. The loader canopy was shipped to Bruceton for possible future evaluation.

Jan 1, 1985

By Merle Randall

Application of a new chemical spray in a mercury mine in which ore rich in native metal was causing salivation among the miners has given such favorable results that it is believed the process will be useful in other mines and perhaps in some plants where similar conditions exist. The process was originated by Merle Randall, professor of chemistry at the University of California. GENERAL PROBLEM The presence of native quicksilver in mines from which the metal is produced has long been a source of trouble and danger to the workers. Men have been sickened and some of them have been disabled by exposure to the vapors present (even in workings that were well-ventilated by ordinary standards) and to contact with dust, dirt, and moisture with which the finely divided quicksilver was mixed. Where the ore was rich and this exposure was considerable men were able to work only a few days or weeks; where the exposure was less they were weakened and subject to ailments often attributed to other causes.

Jan 1, 1942

By R. R. Sayers

The effect of comparatively low concentrations of carbon monoxide for short periods and under normal air conditions.of temperature and humidity , with the subject at rest , was studied by Dr. Yandell Henderson and his co -workers . In making recommendations to the New York and New Jersey tunnel commissions * he advised that , if the New York New Jersey vehicular tunnel be so ventilated that persons passing through the tunnel would be exposed to not more than 4 parts of carbon monoxide in 10,000 parts of air for not longer than 45 minutes , they would experience no ill effects . supplementary experiments , carried out by us in connection with our studies at the Bureau of Mines experiment station at Pittsburgh, substantiated this advice . ** In continuing our studies on low concentrations of carbon monoxide , we made a few experiments in a gas chamber where the conditions could be accurately controlled . The factors investigatel were : ( 1 ) The effect of long exposure in low concentrations of carbon monoxide ; ( 2 ) The effect of strenuous exercise ; ( 3 ) The effect of high temperature and humidity in low concentrations of ccarbon Lonoxide .

Mar 1, 1922

By W. L. Crentz

The Black Mesa coal field is part of the Hopi and Navajo Indian Reservation in Apache, Navajo, and Coconino Counties, Ariz. The field is in an isolated area with the nearest railroad 70 to 90 miles to the south. Travel is restricted by roads that become impassable during inclement weather. The area is a mesa and rises from 500 to 2,000 feet above the surrounding territory. Water is very scarce, and the nearest stream of any consequence is the Colorado River about 90 miles northwest from the center of the field. Coal beds are found in the Mesaverde formation of the Cretaceous age, but they are uncorrelated and range from subbituminous to bituminous in rank. Huddle2/ estimates the reserves of subbituminous coal in Arizona at about 15 billion tons, most of which is in the Black Mesa field. The geology of the field has been reported by Campbell and Gregory.3/ Coal production is small, and the output is used almost exclusively for domestic fuel in the Indian schools, missions, and trading posts.

Jan 1, 1955