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By John G. Kovac

A computer simulation has been developed to estimate the chances of a miner making a successful escape while wearing a SCSR. The model takes into account: (1) training in the use of SCSRs, (2) apparatus integrity, and (3) the oxygen cost of a mine escape. This Bureau of Mines report examines survival odds for a prototypical escape, and illustrates how these odds change when SCSR training is improved.

Jan 1, 2009

By Ralph H. Whaite

The Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region is described. A catalog of the maps that have been microfilmed in the Eastern Middle anthracite field--the first area to be covered in the program--is presented. Additional catalogs will be published as significant mining areas are completed.

Jan 1, 1965

By Ralph H. Whaite

The Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region is described. A catalog of the maps that have been microfilmed in the Eastern Middle anthracite field--the first area to be covered in the program--is presented. Additional catalogs will be published as significant mining areas are completed.

Jan 1, 1965

By Danny Hagood

The drilling of horizontal boreholes as a means of degasification in advance of mining has been tried at Jim Walter Resources, Inc., No. 4 Mine. In a joint venture with the U.S. Bureau of Mines, a series of horizontal drainage boreholes have been drilled in the panels of an advancing continuous miner section with impressive results. The combined methane gas production rate has ranged from 205,000 to 680,000 cfd (cubic feet per day} with individual "in-seam" horizontal holes producing up to 332,000 cfd. The methane liberation from the ribs for the entire panel length has decreased from an average of 8.75 cfm (cubic feet per minute) per 100 feet of entry to 4.05 cfm per 100 feet, a 54 per cent reduction. The actual gas concentration as measure at the surface discharge point normally ranges from 85 per cent to 95 per cent methane. As a consequence of the significant reduction in methane liberation rates from the panels of the section, a 50 per cent increase in productivity from the section has been realized.

Jan 1, 1983

By James W. Ballard, H. H. Schrenk

"The X-ray method of quantitative determination is advantageous because it permits determination of compounds rather -than ions or elements; for example, the direct determination of quartz in silicates,4/,5/,6/ The method also takes into account the finest particles of a sample, which may be lost in wet chemical methods because of solubility or in petrographic methods because of limitation of the microscope. The sample is usually reduced to a powder and is easily prepared,7/ only a few milligrams of material being necessary. The sample and its chemical composition are not destroyed and may be used for further analysis by X-ray diffraction or by other methods.This paper presents in detail some of the more essential problems that arise in the application of X-ray diffraction to quantitative chemical analysis, Photometric measurements are discussed in connection with line intensities and the choice of X-ray film. The internal standard method, successfully used in spectrographic analysis, is applied.Copper K-alpha X-rays from a demountable research-type X-ray tube were used with a camera of 20 centimeters radius with a cast-lead-slit collimating system. A combination of a tilted wedge and a lead-slit collimating system permitted irradiation of a large amount of sample with X-rays. This tended to minimize errors due to possible inhonogeneity of the sample, to decrease the time of exposure, and to keep the lines on the X-ray film to a minimum width. There was sufficient dispersion of the lines for satisfactory analysis of most samples. Power was furnished the tube by a. source of constant high potential consisting of a synchronous motor generator furnishing 500-cycle power to a 100-kv. transformer, rectifying valves, and a condenser filter circuit. The X-ray tube was operated as a gas-type tube at 35 kv, and 20 ma,, the exposure times varying from 1 to 2 hours. The constant output of X-rays from the tube, indicated bar an exposure meter built for the purpose, was satisfactory.The recording microphotometer8/has been described. It was found preferable to a nonrecording instrument for measuring blackening of lines above a background on X-ray films. This background, which usually occurs, is sometimes complicated by numerous peaks from lines of complex diffraction patterns. is microphotometer record of the pattern, therefore, facilitates the location of the background 'and the measurement of the heights of the peaks and thus contributes to the accuracy of a determination."

Jun 1, 1946

By Thomas C. Denton

The Old Reliable copper mine was first examined by Harlow D. Phelps , an engineer of the Bureau of Mines , in October and November 1942 , in compliance with a request from the War Production Board , which furnished copies of assay maps of the 100- and 200-foot levels and requested that they be check-sampled . The author and R. li. Grantham and W. D. Hughes , engineers of the Bureau , made a second and more detailed examination later , after a number of manways had been opened that were inaccessible when the first examination was made .

Feb 1, 1947

By H. E. Powell, T. E. Hill, W. A. Calhoun

The object of this investigation was to determine the effectiveness of certain cationic flotation collectors , Ethomeens , in recovering fine particles of lead minerals from mill tailings at a grade equal , at least , to that of the mill feed ( 1.7 percent lead ) . The Ethomeens , derived from tertiary amines having one fatty alkyl group and two polyoxyethylene groups attached to the nitrogen , were evaluated by bench- scale flotation tests . The 14 Ethomeens tested consisted of four groups : Coco amine , soybean amine , tallow amine , and stearyl amine . The best results were obtained with coco amine C / 12 , soybean amine S/ 15 , tallow amine T / 12 , and stearyl amine 18/20 . From a feed containing 0.23 percent lead , rougher concentrate grades of 2.12 to 3.89 percent lead were obtained , with recoveries of 17.3 to 27.5 percent of the total lead . Some of the lead mineral particles recovered had diameters of less than 1 micron . In comparative tests , the Ethomeens , or polyethoxylated amine types of cationic surface active agents , were more selective than conventional xanthate collectors for flotation of slimed lead minerals .

Jan 1, 1964

By R. V. Ramani, K. V. K. Prasad

"This paper was the subject of a cross-disciplinary presentation under the chairmanship of Dr A.M. EdwardsManagers need quality information for effective decision making. This demand, at the present time, is being fulfilled by the increased use of computers via information systems, decision support systems and management information systems. The idea of incorporating intelligence into computers to aid decision-makers has been evolving for over two decades. In recent years, significant progress is reported on applications to business and sciences. In engineering functions, the Artificial Intelligence approach that seems to have great potential is the application of Knowledge Based Systems.The primary objective of this paper is to identify domains in mining engineering where application of knowledge based systems could be beneficial. Incorporation of the expertise required during the analysis and interpretation stages of an engineering design problem through knowledge based systems is recognized as an area of significant benefit. To this end, the components of knowledge based systems for mine ventilation and strata control design are described. The potential applications and limitations of knowledge based systems are outlined. IntroductionCorrect decisions are the key to success in any enterprise. Scope of decisions varies with the echelons of management hierarchy. The decisions of top management are strategic, relating to the long-term future of the organization. In a mineral organization, these deal with such issues as the acquisition of a new mineral property or the diversification of the business to exploit additional markets. At the operational level, a manager is concerned with decisions pertaining to day-to- day eventualities related to production activities and other short-term needs. In either case, the prerequisite is the timely availability and use of information. The difficulty involved in decision-making depends on the situational aspect. In. many cases, the decisions to be made under given conditions are fairly straight-forward and standard. This may be due to experience gained from decision-making in similar situations in the past. In fact, many decisions in operations management are either repetitive or routine."

Jan 1, 1989

By G. L. Hundley

An anhydrous chlorination process has been developed by the Bureau of Mines for the production of copper, ferric oxide, and sulfur from chalcopyrite. The first part of the process is a chlorination step in which elemental sulfur and a mixture of iron-copper chlorides are produced. This paper describes the second step of the process in which the copper and iron chlorides are reacted with oxygen to selectively convert the iron chloride to ferric oxide and chlorine leaving the copper in the chloride form. The chlorides are pulverized and dropped countercurrent to a flow of oxygen in a vertical 20-cm-diam. reactor at 800° C. By leaching with brine, the copper chloride may be separated from the insoluble iron oxide and reduced to copper powder by electrowinning. It has been demonstrated that 70 to 80 pct of the iron can be converted to oxide in a single-stage operation with a chlorine content in the offgas of 80 pct. After removal of the oxygen, this chlorine could be recycled to the chlorination step. A two-stage operation will convert 98 to 99 pct of the iron in the mixture to insoluble oxides. The offgas from the second stage contains 70 pct chlorine.

Jan 1, 1974

A spectrographic procedure applicable to the semiquantitative determination of 29 elements in tungsten is presented. The method is designed to give estimates of impurity concentrations up to 500 p.p.m. Limits of detectability range from 0.3 p.p.m. for the more sensitive elements to 100 p.p.m. for the less sensitive ones. Tungsten metal samples varying in particle size from minus 300-to 30-mesh are excited in the presence of 5 percent germanium with a direct current arc. Germanium acts to stabilize the arc, minimizes the volatilization of tungsten, and serves as an efficient carrier to sweep impurities from the tungsten into the excitation zone. Curves are presented that show the volatilization behavior of germanium, tungsten, and impurities in tungsten at different concentration levels. Data obtained were used as guides in establishing the method of analysis. In the absence of established reliable analytical procedures for determining many impurities in tungsten in the parts per million concentration range, the spectrographic method described here should prove to be helpful in evaluating high-purity tungsten.

Jan 1, 1961

By Ralph H. Whaite

The Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region is described. A catalog of the maps that have been microfilmed in the Eastern Middle anthracite field--the first area to be covered in the program--is presented. Additional catalogs will be published as significant mining areas are completed.

Dec 1, 1964

By Synthia N. McIntosh

The U.S. Bureau of Mines investigated the feasibility of using ammonium carbamate (NH2CO2NH4) leaching to recover manganese from steel plant slag. This investigation showed that treatment of the slag in hydrogen prior to leaching enhanced manganese extraction. Up to 80 pct of the manganese and 50 pct of the iron could be extracted from a silicon steel slag that had been pretreated in hydrogen at 700° C. Two 4-h leaching stages conducted at ambient temperature with a solution containing ammonia and carbon dioxide dissolved manganese and iron as their carbamate complexes. Heating the pregnant solution to 65° to 85° C decomposed the complexes and precipitated the metals as insoluble carbonate salts. Ammonium carbamate leaching of other slags from several steelmaking plants produced lower manganese extractions, which suggests that the method cannot be applied satisfactorily to all steelmaking slags

Jan 1, 2010

By C. Watson Owings

"The mining Industry in the United States is becoming fully cognizant of the hazards of dust in underground mining as well as in surface plants. The dust problem in metal mines has been brought to focus through knowledge of the harmful effects of dust, especially silica, and through adoption of more or less stringent legislation classifying certain types of pneumoconiosis as occupational diseases. The coal-mining industry is aroused principally by the apparently great increase in the dust-explosion hazard resulting from the rapid growth of mechanized mining. The United States Department of the Interior, through the Safety. Division of the Bureau of Mines, has been requested repeatedly to recommend methods of allaying dust in both coal and metal mines. Methods adequate under hand-mining conditions fail to effect satisfactory reduction of dust in more rapid extraction with modern equipment. Studies of methods and equipment for allaying dust are being conducted in both metal and coal mines. Results of these studies are discussed, and indications of possible means of reducing dust concentrations are presented in the hope that the health and 'safety of men employed in the mining industry may be increasingly safeguarded.DUSTThe term ""dust"" is a common one, and yet the meaning is applied to widely different particle sizes. The general term means ""earth or other matter reduced to fine, dry, and powdery particles."" The root from which the word is derived means ""something that can be blown about by the wind."" As a result of tests on the explosibility of coal, the Federal Bureau of Mines has arbitrarily defined dust as being. ""that which will pass through a 20-mesh screen,"" based upon the fact that particles coarser than 20-mesh have little influence on the development of an explosion of Pittsburgh coal-bed dust. The study of dust, from a health standpoint, has given rise to still another definition of dust, namely,- according to Drinker3/, ""solid particles ranging in size from less than 1 micron to about 150 microns."" A micron is 1/25,400 inch, and 150 microns are approximately 1/1,700 inch. Atmospheric dust usually is considered as 10 microns or less, larger particles not being counted under the microscope in determination of dust concentrations."

Apr 1, 1942

By Lloyd A. Morley, Alan M. Christman

General Six open-pit metal mines, five copper and one molybdenum, were visited during the course of the research. Four were investigated twice, in summer and in winter, in order to determine the effects of seasonal variations In temperature and moisture upon the measured parameters, Permission to enter the fifth mine was received too late to make an examination during the summer months. The sixth mine was visited to confirm the results obtained from the other five and specifically, to observe how the project recommendations (as will be presented in this chapter) would apply to open-pit metal mines in general. Information gathered during the ten plant visits is sufficient to form an adequate data base for the report. A complete presentation of all field trip data is given in Appendix 1. Further, a detailed description of the electrical distribution and grounding practices at each mine is also contained there. Typical System. At a typical mine as shown schematically in Figure 62, one or more substations with resistance-grounded secondaries are employed to transform the incoming utility-voltage to the lower potential used by the mining machines, generally three-phase 4160 V. At this level, pit distribution is carried on overhead lines, supported by wooden poles, to supply switchhouses located in benches near the particular piece of equipment. A switchhouse is a small portable (often skid-mounted) structure at the termination of an overhead line which contains disconnect

Jan 1, 1976

By Rogers F. Davis

The Bureau of Mines developed a new method for the determination of oxides of nitrogen in diesel exhaust gas. The procedure, a modification of the Saltzman method, uses a NO2 absorbent for the diesel exhaust gas; the colorless absorbent becomes purple on contact with N~. When used properly this procedure gives satisfactory results in 2 hours, whereas the standard phenoldisulfonic acid method required approximately 8 hours. The new method is not satisfactory for determination of oxides of nitrogen in the overrich fuel to air ratio range.

Jan 1, 1966

By F. E. Cash

Much has been written concerning accidents in coal mines; the fact that accidents cost the employer and employee money is generally well known, but how much accidents actually cost is vague, even in the minds of many operators. Unquestionably there are hazards in coal mining, but many of them can be eliminated; and from the prevention of accidents there can be realized a material saving in dollars and cents as well as in human suffering. In presenting the frequency, severity, and cost of accidents in some Tennessee coal mines, it is hoped that other mines in Tennessee, as well as mines in other States, will by a comparison of the data with their own ex¬ perience be enabled eventually to reduce the number of' their accidents.

Dec 1, 1932

By G. M. Potter

During the investigation of the occurrence of manganese deposits in the western United States, examining engineers of the Bureau of Mines collected samples from four properties in Siskiyou and Mendocino Counties northern California. As the ores were too low-grade to be acceptable to manufacturers of ferromanganese, beneficiation studies were made between 1941 and 1945 to determine the amenability of the ores to concentration. The Johnson and Reynolds properties are near Fort Jones Siskiyou County. The ore occurs in a number of small lenses in that area. Samples were taken for testing for amenability to treatment in a small custom-gravity plant, tentatively planned. by the Waiter Johnson interests of San Francisco. A 2-ton representative sample was obtained from numerous exposed portions of an outcrop on the property of the Mayland Mining Co. The Mayland mine is about 8 miles from Sawyers Bar in Siskiyou County. The ore body consists of stringers and irregular masses of oxide, and. silicate ore scattered through quartz, which these minerals have replaced.

Jan 1, 1952

By P. C. Good

This Bureau of Mines report describes the preparation of phosphoric acid directly from phosphate ore, without prior beneficiation, in a small-scale, continuous process research unit, as part of an effort to improve minerals and metals recovery from domestic resources while minimizing environmental effects. Three phosphate-matrix samples, ranging in grade from 18.2 pct P20S5to 11.9 pct P205, were dry-fed at a rate of 1.82 kg/hr (4 lb/hr) to a continuous-circuit, 12-liter, single-tank digester to yield phosphoric acid and byproduct gypsum filter cake. Comparison with earlier data shows that a significantly improved filtration rate was attained in a single-tank reactor compared with that attained in a five-tank reactor train processing the same ore. Iron and aluminum impurities in the product phosphoric acid averaged about 60 pct higher than amounts reported in commercially prepared, concentrate-derived acid. All gypsum filter cakes prepared had a firm, sandy texture, rendering them physically suitable for stacking or landfill use. Introduction of dry attritioning and air classification approximately doubled the attainable filtration rate when the dry-beneficiated product was digested. In air classification, there was a 12-to 14-pct P205 loss. Depending on the technique used and the matrix grade, overall P205 recovery ranged from about 72 to 89 pct.

Jan 1, 1979

By Gordon L. Kinney

The only economically important mineral currently produced in Bangladesh was natural gas. Bangladesh was not a world? ranked producer of any mineral commodity, but the possibility of producing and exporting commercial amounts of liquefied natural gas (LNG) was being examined. Proved reserves of natural gas were sufficient to supply most of the country's industrial and domestic heating and electric needs and still support an export-oriented LNG plant. Other mineral production was of virtually no significance to the economy, although there were a few prospects for nonmetallic mineral development. Bangladesh continued to make economic progress during 1978 and into early 1979. Gross domestic product (GDP) at current prices rose from $6.6 billion in 1976-772 to $8.2 billion in 1977?78 and $9.3 billion in 1978.79.2 In fiscal 1979, the economic conditions were favorable until a severe drought hit most of the country. It W88 reported that conditions were the worst in 40 years, and 88 of July 1979, substantial crop losses were predicted. The agricultural sector accounts for over 53% of the GDP and about 75% of all employment. The poor weather will cause economic problems in the form of slower growth, larger trade deficits, and a higher rate of inflation. The 1978.79 statistics showed that real GDP increased just 4%.

Jan 1, 1981

The Bureau of Mines equipped a longwall shearer with a water-jet-assisted cutting system and measured dust levels during the cutting of a simulated coal block. The block was cut dry, at a conventional water spray pressure of 190 psi, and with water-jet-assisted cutting pressures ranging from 1,000 to 6,000 psi. At water pressures of 3,000 psi and higher, dust concentrations were reduced by as much as 85 pct via water-jet-assisted cutting in comparison with conventional water sprays. This reduction was achieved without any increase in the water flow rate.

Jan 1, 1986