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By Robert P. Vinson

This report describes three coal mine ventilation studies by the Bureau of Mines in which sulfur hexafluoride (SF6) was used as a tracer gas. One of these studies was conducted to determine air movement and leakage in a sealed area. Another was run to determine the ventilation efficiency of a bleeder system. Finally, a study was made of air leakage across permanent stoppings of parallel intake airways. These studies proved sulfur hexafluoride to be a useful addition to the equipment commonly used in coal mine ventilation analysis.

Jan 1, 1976

By James A. West

COUNTRIES of the Near East, with the world's largest and insist prolific petroleum resources, produced nearly 277 percent of the world's estimated total output of crude& oil in 1964 and accounted for about 60 percent of world exports of this commodity. Although petroleum largely dominated the mineral industry of tine area, production of antimony, chromium, copper, mercury, boron, potash, and phosphate rock was of world significance. Production of crude oil in Near East countries reached a record high of 7,520,000 barrels per day in 1964, an increase of nearly 11 percent over that of 1963. Kuwait maintained its position as the leading producer, accounting for almost 28 percent of the area's output. Saudi Arabia, Iran, and Iraq followed with 22.5, 22.2, and 16.5 percent of total area output, respectively. Despite record production, the Near East, proved crude oil reserve remained in excess of 211 billion barrels, or more than two-thirds of the estimated world proved crude oil reserve.

Jan 1, 1966

By Christopher C. Jobes, Alan G. Mayton, Farid Amirouche

Based on prior mine vehicle studies of operators’ exposure to whole-body vibration, researchers from the National Institute for Occupational Safety and Health (NIOSH) evaluated four seat designs on mine haulage vehicles, with regard to roadway-induced jarring/jolting and operator comfort. Investigators collected objective and subjective data from vehicle operators on two existing and two NIOSH seat designs. This study included time and frequency response data using accelerometers and a data recorder, operator perceptions of jarring/jolting and discomfort levels using a linear visual analogue scale, and data from a questionnaire developed for this study. Results from the analysis of subjective data show that operators generally favoured the NIOSH-designed seats over the existing seats. The results of analyses from the absorbed power method and the threshold limit method, based on ISO 2631-1 (ISO, 1985), support the premise that NIOSH seat designs are superior to the existing vehicle seat designs on both models of mine shuttle cars used in the study. The NIOSH seat designs, featuring viscoelastic foam padding, were more effective in reducing vibration energy for operators exposed to vehicle jarring/jolting. In this paper, the performances of the NIOSH and existing seat designs are compared relative to the operator’s exposure to vehicle vibration (mainly jarring/jolting).

By F. P. Haver

The Bureau of Mines developed a process to extract about 90 percent of the sulfur from molybdenite flotation concentrate by compacting the concentrate with one-quarter of its weight of aluminum powder, heating it at 800° C for 30 minutes, and then allowing the product to react with water. This thermite reduction yields an impure molybdenum alloy plus aluminum sulfide. The latter readily hydrolyzes, to yield pure hydrogen sulfide which can be converted to elemental sulfur by the Claus process. At least 95 percent of the molybdenum can be subsequently recovered as 99.95-percent-pure molybdic oxide.

Jan 1, 1968

By G. R. Hopkins

"Summary An apparent decline in fuel efficiency at refineries, which first became came evident in 1930 and continued through 1933, was checked in 1933 when the average amount of heat needed to refine a barrel of crude oil amounted to 660,000 B.t.u. This compares with an average requirement of 692,000 B.t.u. In 1932 and with a low of 639,000 B.t.u. in 1929. (See fig. 1.) The improvement in fuel economy in 1933 probably was closely related to the increase of 5 per cent in crude runs to stills. As much of the fuel burned at refineries is utilized for purposes other than under crude-oil stills and in relatively stable amounts, it is evident that a material increase in crude runs will usually reflected in a decrease in average fuel requirements. Another factor which has influences fuel economy at refineries in the past is the trend in cracking, a refining process requiring more than the average expenditure of heat. In 1933 production of gasoline by cracking increased slightly, but no appreciable rise in heat requirements resulted as an equivalent amount of fuel was saved in improved technique, particularly in the field of heat exchange.Since the beginning of the refining industry, the transition in fuels has been from solid to liquid to gaseous; in other words, the leadership was first held by coal, then passed to oil, and is now held by gas. In 1933, 54.7 percent of the total heat units generated came from gas, 39.0 percent from oil (including acid sludge), and 6.3 percent from coal and coke. The principal change in the relative importance of the various refinery fuels in recent years has been the rapid growth in consumption of refinery or still gas at the expense of all the other common fuels. Still gas owes its ascendency to its cheapness and availability, and probably it would have become the primary refinery fuel years ago if recovery methods had been perfected. The relative importance of coal showed a small increase in 1933, the first gain recorded since these surveys were inaugurated in 1925. The increase in use of coal was undoubtedly due to increased operations at plants using it,"

Feb 1, 1935

By Earl L. Phillips

The Bureau of Mines conducted laboratory tests on samples of pozzolanic-cement concrete to develop a low-strength backfill. Results show that support costs can be lowered by replacing a portion of the portland cement in mine backfill with pozzolan (fly ash) and lime. Unconfined compression tests on various ratios of fly ash to cement in 84 samples produced compressive-strength curves that can be used to estimate the best backfill mix for any mine.

Jan 1, 1981

By Terry J. Close

The highly-mineralized 43,700-ha Rapid River study area, on the southeast side of Hells Canyon Wilderness and west of the village of Cuprum, in Adams County, western-Idaho, was investigated in 1992 by the USBM (U.S. Bureau of Mines) in conjunction with its Idaho Land Assessment Program. The 1992 study updated data gathered during the USBM's 1974-76 Wilderness investigation. The studies consisted of the evaluation of 61 mineralized sites and the estimations of tonnages, grades, and minability of these sites. Most of the sites studied are in two mineralized locales--Windy Ridge and Jackley Mountain. A few isolated sites, peripheral to the two locales, were also examined. The 61 sites contained more than 340 mine and prospect workings, including about 10,300 meters (34,000 feet) of underground workings, plus 134 drill holes.

Jan 1, 1993

By W. P. Diamond, John C. LaScola, D. M. Hyman

In 1972, the Bureau of Mines developed a direct-method test for measuring the gas content of virgin coal core samples for coal mine health and safety considerations. Since that time, approximately 1,500 coal samples from more than 250 coalbeds in 17 States have been collected for gas content determination. The gas content data, when combined with geologic and engineering studies, can be used as a basis for a preliminary estimate of mine ventilation requirements, and to determine if methane drainage in advance of mining should be considered. The data are also critical in delineating coalbed methane resources and in utilization feasibility studies. This report makes the Bureau's extensive data base of gas content data more readily available to the coal and gas industries. The data are presented in tabular form, alphabetically by coalbed name and by State. The components of the total gas content (lost, desorbed, and residual gas) are given, Location (State and county), sample depth, coalbed or formation name, and coal rank are included for geographic and geologic identification.

Jan 1, 1986

By A. W. Ambrose

"Records of individual wells form the basis for the successful operation of any company engaged in the production of petroleum. The expense attached to the compilation of records is negligible in comparison with the benefits resulting from their use. There a company has not a complete system of records, immediate attention should be given to the preparation of forms upon which to collect data, and, to the collection of data for these forms. The records needed vary with each district, but for each field a set should be adopted that will best meet the needs of each property. Practically all operators, and particularly all successful operators, agree on the necessity of good records, shopping what the wells have done, are doing, and may be expected to do in the future. Any operator realizes the value of records of sales of oil and should place almost equal emphasis on the records of well logs and histories showing the east and present performances of wells. Indeed, trustworthy records are absolutely necessary for the proper operation of any oil or gas property.Complete records should be kept on each well from the time the location and elevation are determined until the well is abandoned, and the engineer should review old records often enough to be familiar with the past performance of the various wells and with the conditions that affect production. Some of the forms that may be prepared are:--"

Mar 1, 1920

By W. D. Bensema, J. W. Adams, W. W. Scott, H. Dobroski

Measurements of the absolute value of electromagnetic noise and attenuation along a hoist rope were made in an operating hard-rock mine, Lucky Friday Mine, located near Wallace, Idaho. Spectra of electromagnetic noise generated by various pieces of equipment, spectra of specific noise signals at various depths, and noise and attenuation on the 4250 foot (1295 meter) hoist, were measured. Three techniques were used to make the measurements. First, noise was measured over the en- tire electromagnetic spectrum of interest for brief time periods. Data were recorded using broadband analog magnetic tape for later transformation to spectral plots. Second, noise amplitudes were recorded at several discrete frequencies for a sufficient amount of time to provide data for amplitude probability distributions. A third technique gave attenuation data through the direct measurement of field strength at various depths. The specific measured results are given in a number of spectral plots, amplitude probability distribution plots and amplitude curves as a function of depth.

Jan 10, 1974

By Robert M. Becker

A multistage probability model for assessing the reliability of mineral samples following any number of stages of sample reduction is presented. Sample reduction is the process of alternately crushing or grinding and sampling mineral particles prior to assaying. The final multistage model developed accurately describes the ideal sample reduction practice. This model is based on previously developed and experimentally tested models for a single stage of sampling. The problem is approached through the probability distributions for the various stages of sampling. The probability distribution, moments, and moment relationships for a single stage of sampling are first reviewed, and the useful concept of unit moments is defined. In presenting the models for two stages of sampling, emphasis is placed on the physical description of the sample reduction process which leads quite naturally to its mathematical representation. In this representation, crushing or particle-size reduction between the stages of sampling is viewed as a random process with respect to the number and proportion of particles of the various kinds produced. The physical and mathematical description is extended to more than two stages of sample reduction, and the first three moments for any number of stages are developed. In common sample reduction practice the effects of a finite population (finite amount of material) at each stage of sampling appear to be important in describing the variance contribution of each stage. This is also true for the third moment about the mean. An example is cited in which the skewness increases by more than an order of magnitude when several stages of sampling are considered. This is largely due to the dependence of the multistage third moment about the mean on the variance. In general the model and results should be useful in helping to understand, control, and reduce the random errors that arise in the sample reduction process.

Jan 1, 1968

By W. W. Adams, E. E. Getzin, T. D. Lawrence

"The thirteenth annual accident-prevention competition conducted by the Bureau of Mines during the calendar year 1937 was completed with 318 mines and quarries participating. This contest, known as the National Safety Competition, is open to all minas and, quarries employing 25 or more men underground or in the quarry or open pit. The entries are divided into five groups to obtain as nearly as possible uniformity of operating conditions and hazards. The five divisions are: (1) Underground anthracite mines, (2) underground bituminous-coal mines, (3) underground metal mines, (4) underground nonmetal mines, (5) quarries and open-pit mines. A bronze trophy, known as Sentinels of Safety, provided by the Explosives Engineer magazine, is awarded to the winner of each group. The trophy is kept by the winning company 1 year and then transferred to the winner of the succeeding year's contest. Certificates of Honorable Mention are given to plants ranking second, third, fourth, and fifth in each group and to all plants operating without a lost-time accident provided the period of exposure to hazard was not less than 30,000 man-hours. Relative standing in the contest is determined by the contestant's accident-severity rate, which represents the total number of days of employee disability from accidents per thousand man-hours worked by all employees.The 1937 contest was outstanding in that the accident-frequency rate for the contest group as a, whole was the lowest on record. Moreover, with one exception 1934, the accident-severity rate was the lowest ever attained: For frequency, 3S.0 accidents per million man-hours worked; and for severity, 8.2 days lost from accidents per thousand man-hours worked. The rates represent a decline of 62 percent in accident frequency since 1925, the first year of the contest, a remarkable accomplishment both for the contest group and for the purpose of the contest because a majority of the contestants have not only participated during the past year but have been enrolled several years, some enrollments even dating back to 1925."

Aug 1, 1938

By John M. Devine

The oxygen bomb-is used extensively for determining sulphur in petroleum, although it has been suspected that the results obtained with this method are somewhat lower than the true varies. In this paper are compared the results given by the oxygen-bomb and Carius methods, the latter being generally accepted as the standard procedure for the determination of sulphur in organic compounds. The Carius determinations given hero were made in connection with a special study of this method.4 Only petroleum oils of the less-volatile type are covered in the present work. Summary and Conclusions. When used with oils containing 2.3 to 0.15 per cent of sulphur the oxygen-bomb method gives results that are consistenly if slightly lower than those obtained with the Carius method. This variation, for the oils used, amounts to 3.1 per cent (on tae basis of sulphur present) for the sample containing 2.47 per cent of sulphur, and gradually increases (as the percentage of sulphur in the oils decreases) to 7.3 per cent for the oil containing 0.15 per cent of sulphur. With the oils studied the presence of ammonium nitrate in the bomb does not influence the results materially.

Jan 1, 1928

By Martin Hertzberg

The Bureau of Mines 8-liter flammability system was used to study the effectiveness of a variety of powdered inhibitors in preventing the propagation of explosions of coal dust or methane in air. Over 35 different chemical additives were evaluated against Pittsburgh seam pulverized coal. The least effective inhibitors were the carbonates, which required mass additions in the range of two to three parts inhibitor to one part of coal dust in order to prevent propagation. The most effective inhibitors were the derivatives of ammonium phosphate, which were effective quenching agents at additions of only one part inhibitor to four parts of coal dust. Alkali halide powders were of intermediate effectiveness. These laboratory-scale results are in good agreement with full-scale mine experiments in all cases where detailed comparisons have been made. Data were also obtained for the effectiveness of several of the same powdered inhibitors against methane-air explosions. Their relative order of effectiveness and the concentration ranges required for quenching the gas explosion are comparable to those measured for coal dust explosions. Data are also presented for the effectiveness of N2 and CF3Br addition. Some preliminary data are also presented for powder addition to methane burner flames. Those data are compared with other burner data and evaluated in terms of their relevance to explosion tests.

Jan 1, 1982

By C. K. Rose

A hydraulic scaling rig was placed in operation at the Bureau of Mines oil-shale mine near Rifle, Colo., in 1953. The rig consists of a self-leveling platform mounted on a hydraulic-powered boom. The boom is mounted on the bed of a diesel truck. The equipment provides a movable work platform from which two men can work in safety and comfort while barring loose rock from the backs and walls of the rooms, pillars, and haulageways. INTRODUCTION As a part of its synthetic liquid fuels program the Bureau of Mines has developed a mine in the richer oil-shale beds of the Green River formation near Rifle, Colo. An important part of the work of the Oil-Shale Mining Branch is investigation of techniques for low-cost mining of oil shale on a commercial basis. It is evident that scaling loose rock from the high backs and walls of the mine represents a portion of the direct mining cost. This paper describes the development of a scaling rig for operation in the upper heading of the mine, which is 39 feet high.

Jan 1, 1954

By Stephen C. Brown

THE expansion of the world economy which has been in process since 1958 continued in 1963 and both production and consumption of minerals rose. Gross national product (GNP) rose sharply in the United Kingdom and Japan, continued to expand in the United States and Canada, and maintained a high though slightly declining rate of growth in the European Economic Community (EEC) despite the appearance of excess capacity in certain lines and inflationary pressures in Italy and France. The steel and motor vehicle industries both increased output in North America, Western Europe, and Japan. The less developed areas benefited substantially from an improvement in their terms of trade, and their export earnings increased some 8 percent in 1963; although estimates of GNP for the majority of them are 110t yet available, it is probable that this increase was partly reflected in a substantial rise of GNP.2 In the United States the expansion was steady and extended through all sectors of the economy producing no distortions likely to disturb its continuing growth; at yearend with unemployment still at about 5.5 percent of the labor force and operating rates of industry estimated at about 87 percent of capacity, there was a substantial margin for further expansion. Though the balance of payments was still in heavy deficit for the year, in the last half it was moving rapidly toward equalibrium as net exports rose and capital outflows declined; prices were relatively stable, inventories increased only slightly and the activity of mineral-consuming industries remained high, steel output rising by 11 percent to highest level since 1957 and the auto industry output equalling the 1955 record.3

Jan 1, 1964

By Bryan F. Ulrich

If resin-grouted roof bolts are not installed correctly, mine roof reinforcement can be affected, and roof falls can result. A bolt installation variable that is readily controlled by the mine operator is annulus thickness. The objective of this U. S. Bureau of Mines investigation was to study the effect of annulus thickness variations on the integrity of 3/4-in-diam resin-grouted bolts. Forged-head test bolts, 2 and 1 ft long, were installed in concrete blocks that had been drilled with 1-, 1-1/8-, 1-1/4-, 1-3/8-, and 1-1/2-in-diam bits. Standard pull tests were performed; then the concrete was broken away from the bolts so that grout mix quality could be inspected. It was found that the optimum annulus thickness is 1/8-in (l-in-diam drill hole), and as annulus thickness increases from the optimum, there is a corresponding decrease in grout mix quality, effective grout ratio, and axial stiffness.

Jan 1, 1989

By John J. Mulligan

Ear Mountain is an isolated mountain mass that rises abruptly from the coastal plain on the northwest shore of the Seward Peninsula. Geologically it resembles the more accessible Brooks Mountain and Cape Mountain areas to the southwest, being composed of a granitic core surrounded and partly capped by metamorphosed sediments. The occurrence of lode- and placer-tin deposits in this area has been known since the early 1900's, when the Seward Peninsula region was prospected extensively for both gold and tin. The Federal Bureau of Mines investigated the tin deposits in the Ear Mountain area during the 1953 and 1954 field seasons. The objectives were to delimit the areas in which tin minerals occur, as a guide to future prospecting, and to determine the amount of tin in the known prospects. Work by the Bureau of Mines included both placer and lode sampling.

Jan 1, 1959

By Arcy P., D&apos Banister

Several gold-antimony geochemical anomalies were outlined near Stibnite, Idaho, using the humus sampling technique. Several hundred reconnaissance humus samples were collected and analyzed by a combination fire-assay atomic absorption method. The results partially outlined several gold-antimony anomalies and are very encouraging for further work in this part of Idaho.

Jan 1, 1970

By E. J. Gleim

In the movement of self-controlled direct-current machinery, particularly shortwall cutting, machines, from one place to another in coal mires, "nipping" or it stinging" has been practiced quite commonly. These terms refer to the method of obtaining current for propelling or tramming the machines along trolley haulageways by sliding the trolley trip (hook or nip), which terminates one conductor of the trailing cable, along the trolley wire. This is usually done by the machine operator or runner while sitting on the machine truck and holding the nip terminal against the trolley wire as the machine travels along the rails. This procedure is objectionable for several reasons. Under the best conditions, the area of contact between the nip and trolley wire is snail end, consequently, sparking and flashing ore most likely to be continuous as the machine proceeds. This is undesirable, not only because of the detrimental effect of electric flashes upon eyesight, but because of the pitting and roughening the trolley wheels which decrease the efficiency of current collection by locomotive trolley wheels and shoes and at the same time shorten their useful life by increased wear.

Jan 1, 1939