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By Bertrand L. Johnson

As potash is more necessary to the agricultural economy of the United States now than ever before it is gratifying to find that the virtual stoppage of imports from Germany in late 1939 caused none of the anxious foreboding that gripped American farmers in 1914. For long decades this country, in common with tie rest of the world, depended upon German potash, but today our expanded needs can be mot from domestic sources. The present armed conflict in Europe, like that of 1914, disrupted a world monopoly, but the cartel that in recent years controlled 90 percent of the world output (see fig, 1) was an international syndicate comprising French, Polish, and Spanish as well as German producers and having reported sales agreements covering production in the U. S. S. R. and Palestine. The break-up of these commercial agreements has necessitated readjustments but generates no such alarm as the closing of a single source of supply. In striking contrast to the critical shortage that developed a quarter century ago, no increase in prices has occurred or is anticipated in the domestic market.

Jan 1, 1940

By C. H. Fisher

[Many methods of analyzing tar oils for their tar acid and base content have bun employed in connection with both academic and. industrial investigations. Most of these analytical procedures are based on the diminution in volume caused by extraction with alkali and mineral acids (contraction method), although other methods haves been employed.4/ In many instances the adoption of an analytical method was not preceded by adequate study, and, as a consequence, the literature, on this subject is conspicuous for its contradictory claims and recommendations. It has bin shown in the, case of certain synthetic solutions5/ that large errors may result if the analysis is carried out by simple extraction with alkali and mineral acids.]

Jan 1, 1936

By C. H. Fisher

[Mxny methnhs of ,analyzing tpr oils fnr thoir tar acid ~nd base cnntent hava boon employL~d in connection mith both ac~d,.mic and. industrial investigs- tions. Mnst of thznu nnalyticel proc?durn~s aro bpsed nn th; diminution in volums caused by extract lon sit5 alkali 5 minL+ra,l acids (cantrsction rn,>thod) , although othrr mr~thrids havu &apos;sL<on ?q~lnglt 8 . In many instmccs th-: donti ti on of RT~ m~lytic~l m ithod was not ;r.:c ~d~d by ~d.jqunt9 study, and, ns 3 cone+ qucnce, tha lit .,ratur ? on thls sub,jr:.ct is consoScuous for its cnntr~dictnry . claims and rocnmmondatinna.. 1.t tiR.s b9~n shoyn in th;, cnsn of c.lrtn.in synth?tic solut innsfi/ thnt larg~ jr-orn sny rcsult if th2 ,mnlysis is c~rri~d out by sim~la extraction wi.th alidi r.nd min 3rd ncids.]

Jan 1, 1937

By Sean Gallagher

This report was written in an effort to provide better control measures for low back pain (LBP) and low back disability in the mining industry. There are numerous factors associated with development of LBP, many of which can be effectively controlled while some cannot. Better job design is promoted as the best method of reducing cases of LBP and can also reduce the disability (i.e., lost time from work) associated with LBP when it happens. The report draws attention to what is currently known about LBP, what the causes are thought to be, and discusses recent back injury trends in the mining industry. Research describing unique physical demands in mining, such as the capabilities and limitations of working in awkward postures, is also presented. Methods that can be used to prevent initial LBP episodes are provided, including facilities design and layout for materials and supplies, use of mechanical-assist devices, improved design of lifting tasks, and better seat design. Methods of reducing the disability associated with LBP (including workplace design, proactive return-to-work efforts, communication, and management commitment) are also discussed. The report concludes that control of LBP and disability in mining requires a comprehensive approach to limit the repetitive loading that can occur on the low back due to manual materials-handling tasks and exposure to whole-body vibration (WBV). Specific recommendations include the following: ? Successful LBP prevention efforts require a proactive program that has strong management commitment and incorporates employee involvement. ? More efficient supply handling systems and use of mechanical-assist devices can greatly reduce exposure to hazardous lifting tasks. ? Lifting tasks should be designed to minimize low back stress. Tools to evaluate and redesign lifting tasks are presented. ? Improved seat design can reduce exposure to WBV and improve posture, leading to reduced LBP risk. ? The disability associated with LBP can be reduced. Getting the worker back on the job as quickly as possible is in the interest of everyone involved.

Sep 1, 2008

By John J. Mulligan

Lead-silver deposits in the Omilak area, on the western slopes of the Darby Mountains, Seward Peninsula, Alaska, were investigated by the Bureau of Mines, during the 1953 and 1954 field seasons, as a part of the U.S. Department of Interior&apos;s continuing program for the development of Alaska&apos;s resources. The Omilak area was the scene of early day prospecting and mining activity. The Omilak mine, which operated from 1881 to 1890, was the second producing lode mine in Alaska; the first was a small gold mine near Sitka. Several hundred tons of ore were produced at the Omilak mina; as an indication of grade, 41 tons shipped from Omilak in 1889 contained 75 percent lead and 142 ounces of silver per ton. A prominent, nearby occurrence of lead-silver minerals, found but not explored during this period, has since become known as the Foster prospect. Subsequent exploration of this prospect revealed an abundance of massive galena occurring on an outcrop and as float scattered through limestone talus. Evidence of lead deposition, together with the generally high silver content of lead ores previously shipped from the district, indicated that deposits might be found which would be commercially valuable even in this remote area. To investigate the possibility, the Bureau of Mines made a reconnaissance of the Omilak area and did bulldozer trenching, diamond core drilling, and sampling at the roster prospect. Data resulting from the investigation are presented in detail in this report and are summarized in the following paragraphs.

Jan 1, 1962

By P. G. Barnard

The Nation&apos;s steel industry is largely dependent on shipments of manganese from foreign sources for steel production. An adequate substitute for the manganese requirements of our present steel technology would improve our national self-sufficiency and also contribute substantially to the conservation of our manganese resources. As each of these objectives is a major interest of the Bureau of Mines, possible substitutes for manganese in steel were investigated. Titanium was selected as the most promising substitute because the published results of several investigations indicate that titanium would perform the most obvious function of the manganese in steel: The elimination of iron sulfide and its deleterious effects. The investigation involved extending the published data on titanium additions in steel to provide enough information for an accurate evaluation of the practical value of the substitute. Therefore, quantitative data were obtained on the partition of sulfur and carbon between iron and relatively small titanium additions.

Jan 1, 1962

By W. N. Marchant

The Bureau of Mines performed chemical research to elaborate details of sulfur chemistry pertaining to the citrate flue gas desulfurization process in which sulfur dioxide (SO2), absorbed (as bisulfite ion) in a buffered sodium citrate solution, is reduced by hydrogen sulfide (H2S) according to the overall reaction 2H2S + HSO3 + H+ ? 3S + 3H20. The rate-limiting step in the process was shown to be the reduction by H2S of thiosulfate (S2031-) that is formed as an intermediate. Pseudo first-order kinetic measurements were made at room temperature to retard the reaction sufficiently that adequate analysis was possible. These measurements showed the rates of the following net processes to be -d [S02]/dt (pH 4.5) = (0.409±0.050)min-1 [S02]; d [S2032-]/dt (pH 4.5) = (0.199±0.017)min-1 [S02]; -d [S2032-]/dt (pH 4.0) = (0.0437±0.0265)min-1 [S2032-]~1; -dH2S/dt (pH 3.9) = (21.6±3.0) mmoles/min-atm [H2S]g1.4, where [H2S]g is the partial pressure of H2S in the gas phase, in atmospheres, and the rate describes the consumption of H2S, in millimoles per minute; d[S]/dt (pH 4.0) = (38.0±3.4)min-1 [H2S]1, where [H2S] is the concentration of H2S in solution. Hydrogen ion consumption during the slow phase of regeneration was shown to occur at (2.1±0.5) times he rate of thiosulfate consumption, which is interpreted as evidence for the following as the rate-limiting reaction: 2H2S + S2032- + 2H+ ? 4S + 3H20 A scheme consisting of five sequential general reactions is proposed to account for sulfur formation.

Jan 1, 1981

By D. A. Paice

A portable calibrator to check tie trip setting of dc circuit breakers within an accuracy of +5% has been developed for the Bureau of Mines. It operates from a 300 volt dc trolley wire to provide controlled current pulses of 120 milliseconds duration and continuously adjustable from 1400 to 3600 A. These current pulses enable a breaker dc trip current to be determined and subject the contacts to full current rating. The equipment is simple to use and weighs 86 pounds. Connections are made with protected, clamp-on leads which are separately connected and weigh about 22 pounds. An accurate calibration procedure takes less than 5 minutes to complete.

Jan 1, 1978

By John W. Kopp

Stemming is used in blasting operations to help contain explosive gases as long as possible. Stemming can reduce airblast, improve fragmentation, and reduce the chances of hot explosive gases igniting methane and dust explosions in underground mines. Stemming is required in underground coal mines but is generally not used in underground metal and nonmetal mines. Some underground metal and nonmetal mines are classified as gassy and can require special blasting procedures such as the use of stemming to minsure the safety of miners. The types and amounts of stemming material that are desirable in underground metal and nonmetal mine blasting to ensure good or improved fragmentation while containing the hot gases are largely unknown. This Bureau of Mines research examined the effectiveness of differing lengths of stemming by measuring stemming ejection times as related to burden movement. With properly stemmed blasts, stemming is contained until some burden movement has occurred. Test blasts at two surface limestone quarries were evaluated using high-speed photography. For the conditions of these tests, a stemming length of at least 26 charge diameters was found to prevent premature stemming ejection. In tests with stemming lengths of 16 charge diameters, the stemming was effective but there was early venting of hot gases through fractures in the rock. Further testing with other rock types, hole diameters, explosive types, and stemming materials as they affect incendivity is recommended.

Jan 1, 1987

By John J. Henn

Ten proposed processes for the recovery of manganese from domestic resources as a high-grade oxide product are described. Nine of the processes employ sulfur dioxide, sulfuric acid, or a combination of both for leaching. The tenth process utilizes sulfur dioxide to sulfatize the ore at 600° to 850°C before water leaching. In addiction to these ten complete processes, six processes from the patent literature are described. Methods for receovering MnSO4?H2O are also reviewed.

Jan 1, 1968

By Maurice E. Bailey

The purpose of this study is to determine worker acceptance of modified mine equipment at various intervals during a twelve month period. A survey instrument was administered to the workers by two experienced miners in four interviews. All four interviews showed a significant positive response to all modifications, except the small size of the cab of the shuttle car; however, the small size produced significant negative responses with respect to comfort in each of the four interviews. Initially, (interviews one and two), there were significant negative responses with respect to manufacturer receptivity to operator suggestions and program management follow-through on operator suggestions; however, the third and fourth interviews showed no significant negative responses with respect to these items. Likewise, there were significant neutral responses in the first two interviews; however, the third and fourth interviews showed no significant neutral responses with respect to these items.

Jan 1, 1975

By James Paone

This report shows the feasibility of predicting drillability, analytically, by using regression analysis techniques. The approach is new in diamond-drilling research. Further, the study shows that this technique may be of value to drill manufacturers and others in mathematically delineating performance characteristics of new drills in specific rock types. Another application might be the prediction of penetration speeds in extraterrestrial material based on the physical properties of the materials as samples become available. Prediction equations for penetration rates are presented for 9 rocks drilled in the laboratory and for 20 rocks drilled under field conditions. The prediction equations are based on drill operating parameters and on characteristics of the rock penetrated. No single physical property appeared consistently in the best predictor equations, and all the physical properties were found to be highly correlated with each other.

Jan 1, 1966

By Cecil E. Lester

Since the advent of coal mining, the minimal lighting in the under¬ground working place has been an obstacle to the safe and efficient performance of the miner&apos;s many tasks. Compounding this problem is the fact that the machines being operated in the working place are so large that the vertical and horizontal clearances around the machinery are severely limited. Consequently, in these poorly lighted and congested working places, the machine operator is unable to utilize his peripheral vision. He cannot see hazards as they develop and, too often, cannot react in time to avoid serious injury or death to himself or his fellow miners. The greatest hazard to miners inby the last open crosscut is from falls of roof which are often preceded by warning signs such as falling rock fragments, roof supports taking weight, or a sudden reduction in the height of the working place. These warning signs often go undectected because the machine operator&apos;s attention is focused on the small circle of light emitted from his cap lamp. Congress recognized the illumination deficiencies, and, in the Federal Coal Mine Health and Safety Act of 1969, charged the Secretary of the Interior with the authority and responsibility for development and promulgation of minimum standards for illuminating working places in coal mines. These standards have been developed and, as stated in the April 1, 1976 Notice, Federal Register, Volume 41, No. 64, will be promulgated on October 1, 1976, as mandatory regulations under Section 75.1719, Title 30, Code of Federal Regulations. The regulations require that the designated surfaces within the miner&apos;s normal field of vision be illuminated to 0.06 foot-lamberts while self¬propelled mining equipment is being operated in the working places. The term "working place" is defined in the Act as "the area of a coal mine inby the last open crosscut".

Jan 1, 1976

By A. Aly Selim

This report describes the feasibility of predicting percussive drilling rates by equations derived from statistical regression analysis. The least squares statistical method was used and the analysis was performed both by direct and by stepwise linear regression analysis. The predicted penetration rate is a function of the drill power and the physical properties of the rocks penetrated. The results show promise that the technique may be of value in providing a mathematical model by which percussive drill manufacturers and users can predict the performance of a given drill. Experimental work involved two mining type percussive drills. Penetration data for these drills were determined from nine rocks drilled in the laboratory. Drill work rates (power) were determined in a separate series of experiments. Rock physical properties were measured from diamond-drill core samples taken from the same blocks used for percussive drilling.

Jan 1, 1970

By John C. Edwards

The Bureau of Mines developed a mathematical model to predict the oxygen requirements for a miner evacuating a mine. The model accounts for variations in the miner&apos;s escape speed with mine airway height, and for the empirically determined expressions for the weight-specific oxygen uptake rate for upright walking, stooped walking (duck-walking), and crawling. A Fortran computer program that is user oriented was prepared based upon the model&apos;s constitutive equations. Specific instructions for utilizing the program, as well as applications to miner evacuation from a mine, are presented.

Jan 1, 1986

By R. L. Marek

[An important problem in the efficient conduct of industry is that of helping the individual employee to formulate in attitude toward his work which will result in the reduction of accidents and the promotion of safety. Perhaps nowhere is the need greater for this type of psychological training of carefully selected men than at oil refineries whore both the raw materials and the finished products are highly inflammable and explosive in nature. However, the refinery organization usually is well adapted to educational safety activities -- much more so than in the producing, pipe line, and marketing departments where the personnel are more or less scattered; but the sore general principles of conduct hold true in any industrial organization. This problem of directing the attention of tie employees to their specific tasks or helping them to control and frequently eliminate hazards engendered by adverse mental attitude or emotion is met most satisfactorily by carefully selecting applicants and placing theta at jobs for which their ability best fits them. The subsequent training of these carefully selected employees to assure their Most effective work in accident prevention may be accomplished in a variety of gays, ouch as by personal supervision and instruction, inspections, drills, and by the studied use of well thought out safety pamphlets and posters.]

Jan 1, 1932

By L. D. Schmidt, Wm. Seymour, W. S. Landers

"INTRODUCTION The relative value of the various individual physical and chemical properties of coke as a measure of its performance in the blast furnace as aroused considerable controversy but it is generally agreed that uniformity in these properties is extremely important if maximum mum pip-iron production is to be attained. The control of,the bulk density or weight per cubic feet of the coal charge in the coke ovens is a major, and frequently overlooked, factor in producing a uniform product and in efficient operation of the coke plant.This report presents a brief discussion of the general problem of bulk-density control and the results of tests on samples of coke-oven charges from several operating plants experiencing difficulties due to lack of adequate control. These tests covered the effect of moisture and oil content on the bulk density of the coal. Some tests on the effect of a wetting agent and furnenous of gained were also made. A description of the methods used to determine the bulk density of the coals studied in this investigation and of the methods used to apply oil to the coal at byproduct-coke plants are included in this product. No theoretical analysis of the data presented in this report, because the primary purpose of the investigation was to obtain data of immediate practical value to the plants concerned."

Apr 1, 1945

By H. S. Auvil

[The shrinkage of coke after formation is one of the variables that effects the net expansion of the change in both industrial and test ovens. Various test results5/ have been interpreted as indicating that cokes from certain coals shrink to a marked extent and that other cokes show very little shrinkage; but no comprehensive experimental study of the shrinkage of coke after its formation and of the factors influencing this shrinkage has come to the attention of the authors.]

Jan 1, 1940

By Leonard Obert

The investigation reported herein is concerned with the generation and propagation of the strain wave produced in rock by the detonation of a high-velocity explosive. This report is the second of a series that will deal with this and related problems. The rock type in which these experiments were carried out was greenstone. Subsequent reports will discuss similar investigations in other rock types. Specifically, the problem under study is concerned with how certain characteristics of the strain wave, such as the maximum compressive and tensile strain, the maximum time rate of change of strain, the frequency components present in the pulse, the duration of the pulse, and other measurable characteristics, vary with the size of the charge and the distance from the detonation point to the point of measurement. . Other investigators have studied certain aspects of the generation and propagation problem in rock. However, in these studies the travel distances from the detonation to measurement point were comparatively long and the frequency components in the explosive wave were usually under 100 c.p.s. In this study the detonation to measurement distance covered. the range from 2 to 54 feet, and the strain gages and recording equipment employed in the instrumentation of the problem had a frequency response range from 200 to 10,000 c.p.s.

Jan 1, 1950

By R. A. Guereco

Accurate measurements of physical dimensions of a section of stainless steel capillary tubing are presented and used to develop two final working equations for an absolute gas viscosimeter. The effects of pressure and temperature on these dimensions are considered. The internal surface finish and nonuniformity of the capillary bore are discussed, as well as entrance, kinetic energy, gas slippage, and gas compressibility correction factors.

Jan 1, 1967