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By W. R. Hardwick

Nuclear explosive fracturing has been suggested as a method to make hard rock amenable to extraction by a modified block-caving method. To evaluate this possibility, conventional and nuclear blasting practices are discussed, underground mining methods for large deposits and their costs are described, and the cost of fracturing ore with a nuclear explosive and subsequent mining by a modified caving system is estimated and compared with both open-stope and block-caving mining costs. While the direct cost of fracturing the ore in hard rock with a nuclear explosive is less than with conventional explosives, additional costs imposed by the use of nuclear explosives may make their use unattractive for deep mining.

Jan 1, 1970

A spectrochemical procedure applicable to the determination of iron, manganese, and magnesium in titanium metal and to the determination of alloying constituents in three types of titanium alloys is presented. Acid solutions of samples and standards are excited with a spark-type discharge and porous-cup electrode arrangement. The method is particularly applicable for analyzing samples for which a self-electrode method cannot be used. Calibrations are accomplished with synthetic standard solutions, resulting in a primary method that makes calibrations based upon results of other analytical methods unnecessary. Replicate determinations are reproduced to within 5 percent, and the average percentage deviations from reliable chemical values are less than 6 percent. The method can be extended readily to determine additional elements that are similarly soluble and have similar spectral sensitivities. It also can be used as a starting point to establish standards for a direct sparking procedure for analyzing titanium alloys. In view of the absence of established reliable analytical methods in the titanium industry, the spectrochemical method described here should prove to be a timely contribution.

Jan 1, 1956

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 L. C. IlsLey, E. J. Gleim, F. CRAVEN

Electrical apparatus and circuits began to be used in mines about 50 years ago. A search of the literature on mining reveals that in 1882, umping was being done by electricity in some aines of England. One account tells of a small electric locomotive being used in 1882 "to drive eight corves loaded with coal" in a mine near Dresden. In an account of his visit to some English mines, en American in 1892 mentions that he saw underground electric signals, lights, pumps, hoists, and one revolving- cutter-bar 19wall mining machine,. Among the carl electrical installa- tions in the United States was an electric locomotive in the Lykens Valley Coal Co. mine at Lykens Valley, Pa., in 1887. In 1889 the Sperry electric coal digger was being tried out. Tarce mining machines were placed in the Prospect mine, East Palestine, Ohio, in 1890. An electrical pumping plant was put in oneration during 1892 in the Woodward mine of the Delaware, Lacka- rahma & Western Railroad Co. Thus we Almost coincident with the proposed use of this new servant in under- ground workings, came the thought of making it safe in gassy mines. find an account of a design for a protected stationary electric mine lamp proposed by Edison in 1831. Enclosed-type motors rere developed in the United States and shiped to English collieries about 1903. From those early beginnings there has been continuous progress until to-day one finds hundreds of pieces of specially designed electrical apparatus distributed in American coal mines and in mines of nearly all important coal-producing countries. Along with introduction of this equipment grew the idea of the necessi- ty of government aid, in standardization. In most coal-mining countries to- day the governments either directly or indirectly have a considerable in- fluence in guiding the design of electrical equipment intended for use in Pasay mine

Jan 1, 1933

By Jerry Olson

The Bureau of Mines (Bureau) conducted a mineral resource investigation of the French Creek-Patrick Butte study area, in west central Idaho during 1989. No mineral resources or significant occurrences were identified. Other than small scale placer gold, no mineral production is known or recorded. At least 100 lode and 150 placer claims have been located in the study area. Most of the area was examined by ground or areal surveys, and 110 lode and 60 placer samples were taken. Four lode prospects were examined in detail, and all placer claim locations were sampled.

Jan 1, 1991

By Hylton R. Brown

Although extensive research has been carried on to determine the factors affecting the explosibility of carbonaceous dusts, as much has been published on coal-dust and grain-dust explosions recent reports of loss of life and property in explosions if metal dusts emphasize the lack of information on the extent of the dust-explosion hazard in plants manufacturing or handling; aluminum, magnesium, or zinc powder, as well as other metal or mineral dusts. Early investigators believed that only the carbonaceous dusts formed explosive mixtures with air, and it was not until near the beginning of the present century that the explosibility of certain metal and mineral dusts was recognized generally. In his book, entitled "Fire and Explosion Risks," published in 1904, Von Schwartz called attention to such hazards. Many vague references to metallic-dust explosions are found in the literature, such as "a severe explosion of aluminum dust occurred in the Middle West several years ago," but very little information seems to be available on the extent of the hazard, the number of explosions, or the amount of loss caused by explosions in pants handling metallic or mineral dusts or powders other than those of a carbonaceous nature. A search of the records of insurance companies, rating bureaus, fire underwriters,and fire-protection associations as well as the files and records of Government agencies has been made to obtain authentic data on explosion losses. To indicate the extent of the hazard a summary of laboratory tests covering the explosibility of certain metal dusts, with brief reference to their uses and Methods of manufacture, and the data compiled from the information available on losses are presented in this publication.

Jan 1, 1941

By Jerry J. Gray

Transportation charges for mineral commodity movements in western Oregon and western Washington were determined mainly by a stratified random sample canvass of producers. Total 1965 mineral production value for this area was $53.3 million; the cost or charge to move this production from the mine to the consumer or to the point of consumption was determined to be an additional $38.7 million. Thirty seven companies were contacted as a sample out of a total population of 349; the statistically expanded sample production value deviated 3.6 percent from that obtained by the Bureau's annual canvass. The agreement between the sample results and the canvass totals demonstrated the effectiveness of the sampling method for obtaining data with a predesigned level of accuracy. For comparison, the north-central Idaho and western Montana area was studied, A random sample experiment was designed, but because of the dominance of a few major companies, a random sample technique would have required more visits to producers than if only the larger firms were contacted. Eighty-four percent of the 1966 mineral value ($198.6 million) was accounted for by interviewing 27 firms out of a total population of 199. Total transportation costs or charges for the area were $26.7 million. The significant difference observed between the relationship of minerals production value and transport charges between the two areas investigated can be attributed to the difference in the minerals produced. The western Oregon and western Washington region is a nonmetals-producing area as opposed to the predominance of metals production in the Idaho-Montana region.

Jan 1, 1968

By P. A. Cox

Guidelines are provided for the design of explosion-proof electrical enclosures that will meet MSHA certification requirements according to Part 18, Title 30, of the Code of Federal Regulations, and fulfill their intended service underground. The guide covers only those aspects of design which affect enclosure strength, ruggedness, endurance and flame path, i. e., the enclosure ability to properly contain an internal explosion. Internal static and explosion pressures, external impact and thermal heating load are treated as well as the proper selection of materials and welding procedures.

Jan 1, 1985

By C. A. Herbert

Timber decay is due largely if not wholly to a fungus growth on the timber from which it derives' food; a warm, moist atmosphere is necessary for rapid growth. The decay is spread from infected timber to sound timber by countless microscopic spores or seeds given off by the fungus growth and carried by air currents or by long, cottonlike threads, which spread from timber to timber. Haulage roads in most mines in the central coal fields are also return aircourses; hence moisture and temperature conditions are ideal for the rapid decay of mine ties and mine timber. Possibly the return air, which contains a higher percentage of carbon dioxide than normal outside air, also stimulates the growth of fungi. Those familiar with coal mining have observed the more pronounced growth of fungi and decay of timber in poorly ventilated worked-out sections of mines where the air is moist and where usually the percentage of carbon dioxide in the air is considerably above normal.

Jan 1, 1934

By P. H. Mutschler

The Bureau of Mines studied the Chattanooga Shale to determine the quantity and quality of the uranium resources present and to assess specific environmental effects of mining the shale. Geologic data and chemical analyses, mainly concerning a 12-county area of Tennessee, were compiled from previous published and unpublished reports. Uranium resources in the Gassaway Member of the Chattanooga Shale in this 12-county area were estimated to be between 4.2 and 5.1 million tons, contained in 76 to 91 billion tons of shale. These figures represent inground tonnages and do not allow for mining or processing losses. Depending upon efficiency of mining and processing systems, enough uranium could be available to satisfy a large part of the cumulative domestic and world demand through the year 2000. A model was developed which assesses the total tons or acres of shale to be mined if the Gassaway Member were to satisfy 1 percent of the United States demand for uranium in 1991. This partially demonstrates the environmental impact of mining the shale and is easily factorable to any specified demand.

Jan 1, 1976

By G. A. Smyres

A GaC12--B2 l-eachtng procedure and meEal-recovery method for treating an arsenical Cu-Co sulfide concentrate was developed by the Bureau of Mines as an alternative to smelting, which is no longer considered an environmentally acceptable method for treating arsenic-containing ores. The procedure involved leaching in a CaC12 solution with CaC03 for 96 h at 26 pct solids (concentrate and CaC03), 1150 C, and a pressure of 50 psig (345 kPa) with oxygen. More than 98 pct of the cobalt and 97 pct of the copper were extracted, and 99.98 pct of the arsenic and 99.9 pct of the iron remained in the leached residue. A filtration rate of 2.9 gal/(ft2.h) [118 L/(m2.h)] and a cake formation rate of 36 Ib/(ft2.h) [172 kg/(m2.h)] were obtained by filtering reacted pulp at 1000 C. More than 99 pct of the copper in the pregnant solution was extracted as CuCl2 by golvent extraction with a new copper extractant. Copper was stripped from the loaded organic with a sulfate-chloride solution, which was used as the anolyte for electrowinning of copper in a membrane cell. Copper plate produced was more than 99.99 pct pure and requi.red 0.81 (kW'h)/lb Cu [1.78 (kW·h)/kg Cu]. Cobalt sulfide was precipitated at pH 3 with Ca(HS)2.

Jan 1, 1986

By W. A. Cole

As the mines get older and the active workings get Farther and farther away from the original mine openings, it becomes increasingly difficult and expensive to ventilate most coal-mines properly. At the same time, the avenues of escape for those employed underground have become so extended' as often to make it impossible for them to make their way out of the mine in the event of a fire, mine explosion, or other emergency. Where such Conditions exist, the only satisfactory solution is to make new ventilation and emergency-escape openings near the active mine workings. At most mines this would necessitate sinking shafts, which is often slow and expensive.

Jan 1, 1945

By Joseph S. Coffman

To determine the availability of manganese for metallurgical purposes from selected world resources, the Bureau of Mines evaluated the potential production of contained manganese in concentrates based on the demonstrated resources of 23 foreign and 8 domestic mines and deposits in 9 market economy countries. All but 2 of the 23 foreign deposits are operating mines; none of the domestic deposits are in operation. The demonstrated resources of the mines and deposits used in this study represent an in situ ore resource of approximately 2.2 billion tons," containing 780 million tons of manganese with a total recoverable production potential of 514 million tons of contained manganese in concentrates. The analyses of mines and deposits in this study indicate that about 213 million tons of the contained manganese (41 pct) is potentially available at a January 1981 constant dollar long-run total cost of up to $1.50 per long ton unit (22.4 lb, or 10.15 kg contained Mn), approximately 428 million tons (83 pet) is potentially available at a cost of about $1.75 or less, and 491 million tons (95 pet) is available at less than $3.30. The remaining 23 million tons, which is potentially available at much higher costs (about $8 to $35 per unit), represents the U.S. deposits. On an annual basis, with a cost range of up to $1.75 per long ton unit, the availability from currently operating mines would last at least 80 years based on 1980 world production data. Total manganese production costs are estimated to comprise mining-8 pet, beneficiation-3 pet, transportation-26 pet, and smelting-63 pet.

Jan 1, 1984

By Steven A. Fechner

In 1984 the Bureau of Mines cunducted mineral investigations of specific sites within the Yentna Mining District. One hundred eight placer and rock samples were taken. Reconnaissance placer samples were collected from drainages in the Talkeetna, Susitna, and Yentna River basins. The highest placer gold values were found in the historic placer gold producing creeks of the Cache-Peters Creek area. Samples taken from an outcrop in the Middle Fork of Iron Creek in the Talkeetna Mountains contained previously unreported high lead, zinc, and silver values.

Jan 1, 2011

By T. I. Weston

This is one of a series of papers being prepared for and published by the United States Bureau of Mines, describing mining and milling methods and costs at crushed-stone plants throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total production costs. It is recognized' tat publication of total production costs might in many instances cause embarrassment to individual producers, as well as to the industry as a whole. However, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no mis-understanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance-of F. W. Horton, mining engineer, United States Bureau of Mines, in the preparation of this paper.

Jan 1, 1933

By Gregory B. Beacher

Analyses have been performed on geotechnical properties of copper, uranium and phosphate (gypsum) tailings materials, with the intent of identifying typical measures of variability within and among sites, and of characterizing such variability for use in reliability modeling of tailings embankments. In all, data from approximately 41 sites were analysed. Fairly consistent results were obtained for within site variabilities. However no one probabilistic model was found to be applicable to all sites. The distributional forms for most of the data sets are regular, and tend toward Normality when spatial trends are removed. At many of the sites sufficient in situ data were available to allow estimates of vertical autocorrelation distances and measurement noise. Available data indicate that variability in pore pressures may have a more important effect than strength property variation. A major problem in interpreting available strength property data results from the unknown drainage conditions during testing.

Jan 1, 1983

By Michael D. Dunn

The Bureau of Mines evaluated a quartz schist formation within the Blue Joint Wilderness Study Area which was identified as having a "high potential" for copper-silver-cobalt-barium resources. Stratiform and remobilized copper occurs near, and bedded barite within, the study area. In addition, the black to gray Proterozoic quartz schist may correlate with the Yellowjacket Formation which contains cobalt-copper-gold-silver deposits at Blackbird, ID, about 30 miles to the south. Eighty soil and 43 rock samples collected across the quartz schist formation were analyzed for gold, silver, copper, cobalt, and barium. During the reconnaissance and sampling, particular attention was given to looking for malachite (copper carbonate) and erythrite (cobalt arsenate, also known as "cobalt bloom"). The sample analyses and geology in this localized area do not provide enough evidence to support the "high potential" designation for copper-silver-cobalt resources. Barium potential still appears high, however.

Jan 1, 1987

By R. L. Soderberg

Large open stopes mined by vertical crater retreat or sublevel s are sometimes backfilled with uncemented sand to support the stope walls and alleviate rock bursts. The failure of bulkheads in two different mines prompted a research project at the Bureau of Mines to prevent a recurrence of these failures. A series of laboratory tests with drains and sand filters was conducted to measure the bulk-head pressures when adequate drainage was maintained. Results showed that bulkhead pressure was reduced to near zero while drains were in operation, as compared to full hydrostatic pressure when drains were blocked or drainage was restricted. A relatively simple, free-draining bulkhead was shown to be adequate.

Jan 1, 1985

By John P. Capp

The feasibility of simultaneously burning several paths through a coalbed to develop a multiple path underground gasification system was investigated by the Bureau of Mines during two experiments, Boreholes were drilled through the overburden and into the coal and arranged in a circle approximately 50 feet from a central borehole. In the first experiment, in an area which had previously been hydraulically fractured,5 air was injected at the center borehole. The coal was ignited at the other boreholes and the fire fronts traveled toward the center, counter to the flow of air, to backward burn paths through the coalbed. Two paths were linked during the first 5 days of operation. The outlets of these two paths were throttled and air pressure was increased to maintain the flow of air, but no other linkages were made. Fourteen days after the two linkages these two paths were opened and gasification was carried on for 10 days, but with only moderate success. In an effort to overcome operating difficulties air was injected at the peripheral boreholes, and the gases were drawn off at the center borehole. Reversed flow operations continued for 12 days and two more paths linked. The heating value of the gas generally was higher than 100 British thermal units per standard cubic foot (B.t.u. per std. c.f.). Because only four of seven paths linked, however, the entire system could not be evaluated with respect to product-gas output and recovery of energy.

Jan 1, 1961

By P. D. Tracy, M. W. Von Bernewitz

"IntroductionA study of 256 coal-mine explosions, which occurred during the period 1909-1924 killed 4113 men and injured 570 others, reveals the fact that there are the critical times of day when explosions are most likely to occur, and when corresponding care should be exercised to guard against disaster. Of these 256 explosions, 83 straight as explosions, 89 were straight coal-dust explosions, and 81 were mixed gas and dust explosions, while three were undetermined.It has been determined from the times given in these reports (in several cases no times were given,that the critical period in the morning ranges between 6 and 9 o'clock when 83 explosions took place with a peal. at 7;30 o'clock. Of these 55 were straight gas explosions, the remainder being either coal dust or mixed gas and coal dust explosions. The critical period in the afternoon or early ranges between 3 and 7 o'clock, when 113 explosions took place, with a peak at 6 o'clock. Of these, 87 wore straight coal-dust explosions the remainder being neither gas or mixed gas and coal-dust explosions. Between these morning and evening periods is one which might be called the noon period - that is, from 11m to 7. p. m. - when 26 explosions occurred while some of these were normal type of explosions - that is, as to causes - others were of unusual cause and character, and. are discussed later. A number of explosions (29 in all) took place during mid-afternoon, late at night, and early in the morning - that is, after midnight."

Sep 1, 1924