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By Ellsworth Y. Dougherty, Edwards F. Fitzhugh

"INTRODUCTION During the summer of 1945 the Bureau of Mines made approximately 200 miles of reconnaissance magnetic surveys in north-central Mirnesota. The survey started near the western end of the Mesabi Iron Range and extended into the area to the southwest, west, and northwest and also southward to the-northern limits of the Cuyuna Iron Range. The purpose of the survey was to data to assist exploration for iron ore in the region through:1. Supplying a relatively unit form network of traverses, by which and future surveys of localities in the urea ray be correlated. Suggesting localities in which more detailed magnetic surveys may be justified, and, Disclosing localities in which there is lass hope of obtaining significant results from further magnetic surveys.The instrument used was a Hotchkiss Superdip, and traverses for calibration and comparison were run with a Schmidt-type magnetometer. Field observations and work directly related thereto were carried out under contract by E. J. Lang-year Co., Minneapolis. Engineers of the Bureau of Mines planned, directed, and reviewed the survey."

Aug 1, 1946

By G. W. Jones

In a previous report results were given and a method outlined whereby from a knowledge of the composition of the natural gas and of the inflammability limits of the individual constituents composing the natural gas, the limits of inflammability of natural gas and air mixtures could be closely calculated. This method is based on the application of Le Chatelier's law as modified by Coward, Carpenter and Payman, to apply to a mixture of any number of combustible gases. This law must not be used indiscriminately, because many exceptions have been found. For example, when ethylene, acetylene, hydrogen sulphide, or chlorinated hydrocarbons are present the law may not hold. For a discussion of the rally exceptions which have been found, reference should be made to a report by Coward and Jones. Before this method can be used the inflammable limits of the individual constituents must be known. Also, the composition of the complex combustible mixture, and representative mixtures besides, must be tested both experimentally and by calculation to prove whether Le Chatelier's law may be applied.

Jan 1, 1933

To provide for continuous remote sensing of carbon monoxide (CO) in underground mines. The Approach A transducer module has been developed as a wall-mounted, continuously operating instrument that will measure ambient levels of CO, and produce a signal that is proportional to the concentration.

Jan 1, 1982

By L. C. IlsLey

The Bureau of Mines has collected field data and made laboratory investigations of trailing- cable performance in the hope of developing a better and safer cable for use with permissible mining machines . Because of their better insulation and performance , only rubber- sheathed cables were finally considered . The cables tested represented the product of six manufacturers . : After consideration of the results of the preliminary investigations , the conditions under which cables are used in mines , and the better performance of the later types of cables that were submitted as the investigation progressed , the bureau formulated a performance - test requirement and notified the cable manufacturers as follows : The hazards of the trailing cable are such that the bureau has been unable to extend beyond the machine its formal approval to cover the cable as at present developed . However , in the attempt to reduce the hazard as much as possible , cables passing certain tests will be recommended for this service and it is hoped that several cables will be developed to meet this requirement .

Sep 1, 1930

By H. S. Hardman, G. T. Adams, Will H. Goghill

"Usually a newly developed machine leaves the factory ""on a wing and a prayer."" The manufacturer hopes that the operator will hasten to report defects. In turn, when the suggestions arrive the manufacturer makes the required changes and maintains close collaboration with the operator. Thus the history of our machines of today is written.Laboratory concentration tables are exceptions to growth by experiment and collaboration. Their operation never enters directly into the cost sheet; they are seldom used for longer periods than 10 minutes; and the experimenter, while hurrying to another job, accepts the table, good or bad, for a quick test on his ore. Thus we go back about 50 years when we use the preset in factory-built laboratory table.The Southern Experiment Station, Bureau of Mines, in cooperation with the University of Alabama, recognized the existence of a tabling problem net usually considered. That is, instead of using the table to test the ore, the ore was used to test the table. In this critical examination of laboratory table six defects were encountered (and remedied). They are:"

Oct 1, 1945

By John R. Reeves

The development of an new industry, which must prepare its marketable products at or near the source of the raw material, and ship them to a market which may cover half a nation, is more or less influenced by a number of natural and cultural conditions such as (1) location of plants with respect to a large market, (2) climatic conditions, (3) transportation facilities, (4) labor supply, and (5) water supply. An effort is made in this pager to give in detail a number of the more important of these conditions as they affect, either favorably or unfavorably, the development of the oil-shale resources of southeastern Indiana. The utilization of the New Albany formation for the production of oil will be similar to a large scale low-grade ore proposition in which the raw material can be obtained in very large quantities at a relatively low cost. It appears, therefore, in considering the value of this shale or its economic position in relation to other oil shales, tie cost of mining and preparation for the retort are of prime importance.

Jan 1, 1923

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

All output is saved in the file MFIRE OUT m the di¬rectory and on the disk containing the program The file can be inspected with a text processor and sent to a print¬er, if needed CONTENTS OF OUTPUT FILE The comment lines, reference temperature, air densi¬ty, a table of the units of measure for the results, and the average values are shown at the beginning of MFIRE OUT All input data will be shown in the output file if LOUT on Control line number 1 is _<-1 For each contamination source, a new branch will automatically be setup The new airway and junction ID numbers will not interfere with the original numbering scheme of the data file Next are the results of the selected simulation(s) in the following order network balancing, network balancing considering temperatures, transient-state modeling, and altered equilibrium due to fire and distribution of the contaminants. Depending upon the contents of the data file, and the simulation selected, attention, warning, and error message will be shown at locations where calculations resulted in unusual conditions

Jan 1, 1990

Although coal is found in several locations in Virginia, almost all recent mining has occurred in the southwestern part of the state. Potentially minable reserves are estimated at 2.6 billion tons, slightly less than one percent of the national total. Coal ranges from high- to low-volatile bituminous, and seams average three to four feet in thickness. Virginia produces coal with higher BTUs (British Thermal Units) and a lower sulfur content than the national average. Historically its high quality has made Virginia coal attractive for metallurgical coke production and for the export market. Coal production and related industries have a significant economic impact in southwestern Virginia. In the seven coal- producing counties, coal mining is the major industry. In the two largest coal-producing counties (Buchanan and Wise), over 40 percent of total earning is derived from the coal industry. Virginia&apos;s regulatory program was conditionally approved December 15,198 1, and received final approval May 8, 1984. Its Abandoned Mine Land Program was approved with the regulatory program December 15, 1981, with emergency program authority approved November 13,1987.

Jan 1, 1992

By J. E. Chilton, C. R. Carpenter

The U.S. Bureau of Mines has developed an intrinsically safe carbon monoxide (CO) monitoring system for mines by coupling a fiber-optic data telemetry (FODT) system with a prototype electro- chemical CO monitor. The CO monitoring system can be used in a coal mine as one component of an early fire warning system. This system may be used in belt haulage entries when the entries are used for supplying ventilation air to working places. The FODT accepts a 0.1- to 1.1-V analog signal from the monitor and converts it to pulses (0 to 5 V) at frequencies from 1.1 to 11 kHz that drive a light- emitting diode (LED). An electrically nonconducting fiber-optic cable carries the LED signal to a remote receiver. The receiver analyzes the incoming light signal and displays the measured CO concentration in parts per million. This report discusses the performance of the FODT system and characteristics of the CO monitor such as response times, linearity, and temperature and pressure effects.

Jan 1, 1992

By R. Raines, S. P. Signer

Researchers from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health installed 39instrumented, fully grouted bolts at six test sites in a trona mine retreat panel to study mine roof stability for the improvement of workplace safety. Variables at each test site included bolt spacing, bolt length, roof span, and location in the panel layout. At most test sites, two rows of instrumented bolts were installed, one in or near the intersection created during development and the other in or near the intersection created during second-pass mining. The most significant factor affecting bolt load was roof span. The highest loads were on the bolts installed in the intersections of the 6-m-wide entry. Mining-induced stress resulting from panel layout was the next most significant factor affecting bolt loading. Minor variations in bolt loading could be attributed to changes in bolt spacing and bolt length. Gas pressure release in the immediate roof contributed to some bolts showing compressional loading during gas bleed-off.

By Forrest T. Moyer

General injury experience in the mineral fuel industries was less favorable in 1965. Of the major industry groups, the coal mining and the coke industries had higher injury-frequency and severity rates than in 1964. The oil and gas industries had an increased Tate of occurrence of injuries although the severity rate improved. However, in the relatively small peat and native asphalt industries, the injury experience was more favorable than in 1964. Overall operating activity for the mineral fuel industries, as measured by the average number of men working daily and the total worktime, was higher than in 1964. Moderate declines in employment and worktime in the coal and peat industries were more than offset by gain in the other groups. In addition to the industry classifications included in this chapter, similar injury, employment, and worktime data on the metal, nonmetal, stone and aggregate industries are presented in volume I. Corresponding data for broad classifications of mineral industry groups arc given by States in volume III of the Minerals Yearbook.

Jan 1, 1967

By Maria I. De Rosa

Table 19 and figure 7 show the number of fires and fire injuries for surface coal mines by state during 1990-1999. Table 19 also shows by state the risk rates, employees&apos; working hours, lost workdays, and coal production. For surface coal mines, 215 fires occurred in 21 states during 1990-1999. Ninety-four of those fires caused 93 injuries and I fatality (the yearly average was 21.5 fires and 9.3 fire injuries). Fourteen fires and seven injuries involved contractors. The Ewhr value was 729 x 10° hr (In = 0.026), the CP value was 6,355 x 10° st (Fn = 0.034), and the LWD value was 8,141. Kentucky had the most fires and fire injuries (45 fires and 23 injuries), followed by Pennsylvania (33 fires and 14 injuries), West Virginia (25 fires and 14 injuries), and Indiana (20 fires and 8 injuries). Among these states, Pennsylvania had the highest fire risk rate value (Frr=0.145), while Kentucky had the highest injury risk rate value (In 0.041).

Jan 1, 2004

By E. Shekarchi

The mineral industry of Afghanistan improved substantially in 1976 as asbestos production was begun and feasibility studies were made of possible copper and iron and steel industries. The remarkable event of the year was the introduction of Afghanistan&apos;s 7-year economic and social development plan which covered the years 2976-82. The 7-year plan established ambitious goals for a gross national product (GNP) annual growth rate of 6.3% during its duration. To achieve this target, large increases in expenditures for economic development were programed in virtually every sector of the economy. Foreign assistance, in particular, was expected to finance a large share of new development projects. The major components of the plan were the development of transportation (highways and railroads), oil and gas exploration, construction of a copper smelter to exploit the copper deposits near Kabul, and development of an iron and steel industry to exploit the rich iron ore deposits in the central part of the country. Exports during the plan period were to continue to be principally agriculture products and natural gas to the U.S.S.R.

Jan 1, 1980

By E. C. Lane

"INTRODUCTION This is the fourth in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C.F.R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-36 3/. The second resort gave the same data for motor gasolines sold during the summer of 1936 4/. The third report of the series gave the same data for motor gasolines sold during the winter of 1936-37 5/.This report covers 63 brands of gasoline represented by 1,136 samples excluding the Pacific Coast. Those from the Pacific Coast were averaged by the Pacific Coast technical group before being submitted and are published exactly as they were submitted. In some areas reports were received from five or six companies on the same brands of gasoline, whereas in other areas only one company reported on a brand. Thus, it can be seen that some of the data are more representative than others."

Dec 1, 1937

By C. M. Flynn

The Bureau of Mines prepared and investigated xanthated sawdust adsorbents to determine their effectiveness in removing heavy metal ions from dilute aqueous solutions, mine-drainage waters, and brines. Stripping of the metal values from the metal-laden adsorbent was also investigated. The treated sawdusts had an adsorption capacity of 0.3 to 0.4 meg/g dry adsorbent for Mn, Co, Ni, Cu, Ag, Zn, Cd, Hg, or Pb from feed solutions with pH 5 to 6. The feed solutions tested included mine-drainage waters and geothermal brine. Effluent metal concentrations as low as 0.05 to 0.1 mg/l were obtained at effluent pH values of 6 to 9. The order of affinity of metals for the sawdust adsorbent is Na«Ca~Mg~Mn<Zn<Ni<Cd<Pb~Cu. The presence of Ca, Mg, or Na in concentrations as high as 2 g/l does not seriously impair the heavy-metal adsorption. Metals were desorbed from the metal-laden adsorbent by elution with dilute mineral acids, sodium cyanide, or salts of ethylenediaminetetra-acetic acid.

Jan 1, 1979

By Jeffrey Johnson, Thomas Brady, Radford Langston, Mary MacLaughlin, Hendrik Kirsten

The magnitudes and directions of in situ stresses affect the stability of mine openings, as well as the type and amount of ground support needed to maintain a safe working environment for miners. Using hollow inclusion stress cells, researchers from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health obtained two in situ stress measurements from the face of two footwall lateral drifts at the Stillwater Mine near Nye, MT. The first measurement, obtained in 1997, was collected under the valley beneath the Stillwater River. The second measurement was obtained in 2002 under the main frontal massif of the Bear tooth Mountains in the western sector of the mine. Although few data are available, the major principal stress under the valley has been recorded as nearly horizontal in a north-south direction perpendicular to the ore body, while beneath the mountains, stress runs east-west parallel to the ore body. This paper documents the measurements, describes the in situ stress state, and discusses a finite-difference analysis of the biaxial test.

Improve the safety of salt mine workers by providing a means for quickly identifying areas within the mine that?s how an increased potential for gas and salt outbursts. Approach Outbursts occur in salt mines when a high-pressure pocket of gas is intercepted during the mining process, resulting in a sudden and sometimes catastrophic expulsion of gas and salt. In one case, the amount of gas released through such an event caused an explosion that resulted in five fatalities. The U.S. Bureau of Mines has designed and developed a gas outburst prediction system that can quickly determine the potential instability of areas within rock salt mines. The determination is based on noise measurements obtained from samples of the salt as they are dissolved in water. This system improves upon technology currently available because it provides information in only a few minutes instead of in several days. In addition, present prediction systems are not only time consuming, but expensive because they require laboratory conditions and highly trained personnel to operate them and determine results.

Jan 1, 1989

By David M. Hyman

Outbursts are sudden and violent releases of gas and coal that result from a complex function of geology, stress regime, and gas pressure and content. The Bureau of Mines has reviewed methods for prediction and mitigation of such outbursts in use worldwide, as an aid in selecting the proper techniques for use in specific mine environments. Outburst-prone coal may be distinguished from normal coal by its sorption-desorption velocity. Three types of methods used to characterize the kinetics of sorption-desorption are described; all are based on the ability of outburst-prone coal to release, through desorption, methane or carbon dioxide much more rapidly than normal coals. Other prediction methods, based on borehole samples, are also described. Various mitigation methods described and evaluated include (1) working the least stressed, less disturbed, lowest gas content seam in multiple-seam areas; (2) mine opening geometry; (3) inducer shot firing; (4) water infusion; (5) localized stress relief, using boreholes or by cutting a reliever slot in the longwall face; and (6) other gas drainage methods.

Jan 1, 1987

By Van E. Shaw

Bastnaesite is a natural rare-earth fluorcarbonate of the cerium group that affords an abundant and high-grade source of the lighter rare-earth elements. A simple and efficient method has been developed by the Bureau of Mines for extracting rare-earth compounds from this mineral. Digesting of a flotation concentrate with sulfuric acid converts the rare-earth compounds from fluorcarbonates to sulfates. Action of the acid releases gaseous com-pounds of fluorine and silicon, leaving the sulfated material free of these elements; carbon dioxide from carbonate decomposition is eliminated at the same time. Calcining the sulfated material at 1,200° F. renders the gangue constituents insoluble, whereas the rare-earth sulfates are left in water-soluble form. Leaching with water yields a solution of pure rare-earth sulfates. Bastnaesite could become prominent as a source of cerium-group rare-earth elements. It is rich in the light rare-earth elements and comparatively easy to process; reserves of the mineral are extensive enough to supply a greatly expanded market for many years.

Jan 1, 1959

By A. F. Colombo

Infrared spectroscopy employing attenuated total reflectance (ATR) techniques on thin films of dried gelatinized starch solution was used during Bureau of Mines research to determine the structural and impurity differences in starch products and to correlate these characteristics with the flotation response of a nonmagnetic taconite. All of the starch products evaluated gave spectrograms which were characteristic of the anhydroglucose monomer and its polymerization product. Distinct infrared absorption peaks caused by the protein molecule were observed and were used to classify the starches. Correlation of laboratory flotation of calcium-activated gangue from a Mesabi Range nonmagnetic taconite and infrared spectra produced from gelatinized starches showed that protein impurities and linear chain structure limited the effectiveness of starches as iron mineral depressants. Starch products having spectrograms similar to pure amylopectin were generally good depressants for iron oxides, were effective at about one-half the addition that was required for starches that gave infrared responses similar to pure amylose, and yielded acceptable iron concentrates containing 61.5 percent iron and 6.5 percent silica.

Jan 1, 1969