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By J. S. Dunning

One Federal Bureau of Mines research goal, to minimize requirements for domestically scarce mineral commodities through conservation and substitution, can be accomplished by utilizing more abundant elements such as iron, molybdenum, and titanium. An example of this research is the study of precipitation-hardening, iron-base alloys containing molybdenum and titanium, as substitutes for the high-tonnage stainless steels that are high in imported nickel and chromium. The precipitation hardened iron-base alloys are strengthened by a dispersion of the ternary Laves phase, Fe2 (Mo, Ti). Aluminum and chromium additions changed the solid solubility limits of molybdenum and titanium in a-iron and affected the composition of precipitating phases. A baseline composition of Fe-7Mo-2Ti was selected to study the effects of aluminum and chromium additions on the precipitation-hardening mechanism and microstructure and was also used in studies of mechanical properties and oxidation resistance. The study yielded workable, precipitation-hardening alloys, with elevated temperature strengths equivalent to or superior to types 304 and 316 stainless steels. Chromium and aluminum additions in combination were more effective in providing oxidation resistance than either addition was alone.

Jan 1, 1980

By F. E. Armstrong

An instrument using a gamma-ray backscatter technique for determining the weight-percent incombustibles content of coal dust and rock dust mixtures in coal mines has been built and tested. The unit gives a direct readout in per-cent incombustibles for coal mine dust mixtures containing between 50 and 100 percent incombustibles; calibration of the device requires using a sample of the rock dust employed; this is usually limestone but occasionally dolomite or gypsum. A small americium-24l source is used with a scintillation detector whose output feeds a rate meter. The source-detector geometry used was chosen to reduce the effects of variation in bulk density. Accuracy of the system is within ±3 percent for most mixtures. The instrument is portable and completely self-contained; the rechargeable batteries supply power for 300 to 400 determinations.

Jan 1, 1974

By E. Shekarchi

A year after the Soviet Union invaded Afghanistan and replaced President Amin with their choice, President Karmal, Afghanistan remained in turmoil. In some respects, the political and economic situation in Afghanistan was no better by the end of 1980 than it was preceding the December 1979 invasion. The Government faced widespread and growing alienation and resistance, virulent factionalism within the ruling party, and an acute shortage of material. The mining sector of the country did not fare better either; the only raw material produced in a significant amount was natural gas, which was exported mainly to the Soviet Union. No statistics on production of other minerals and materials were available by yearend. Most of Afghanistan's gas production was from the Hodja-Gugerdag Field, southeast of Shibarghan. The gas flow from this field had been about 300 million cubic feet per day since 1961. An estimated 230 to 250 million cubic feet per day of Hodja-Gugerdag's production was moved by pipeline across the Amu-Darya River into the Soviet Union. Most of the remainder was transmitted eastward to a 105,000-ton-per-year fertilizer plant and an electric power station built near Mazar-i-Sharif with Soviet assistance. After the Soviet invasion, the second gasfield, Djar-Kuduk, in the Shibarghan area, was brought under production. This field, which will produce about 200 million cubic feet per day, consists of four gas zones in the Jurassic and lower Cretaceous zones between 3,000 and 8.500 feet deep. The gas has a high hydrogen sulfide content, with considerable carbon dioxide, A new treatment plant was built at Djar-Kuduk by Soviet technicians under a turnkey contract at the end of 1980. It is believed that most of the Djar-Kuduk's initial flow will be sent to the Soviet Union.

Jan 1, 1982

By Eldon Keith Stanek

This annual report deals with four distinct tasks related to research on the safety and reliability of mine electrical power systems. Task one is to develop tests and the associated instrumentation to detect incipient faults on a mine or any low-voltage power system. Task two is a dual effort related to the digital prediction of electrical transients on mine power systems and laboratory testing of transient suppression devices. Task three is also a dual effort. This task consists of both theoretical and laboratory work to assess both the reliability and the fail-safe characteristics of several items of protective equipment used in mine power systems. Task four consists of an effort to use programmable calculators and/or computer terminals to check overcurrent protective device coordination.

Jan 1, 1976

By Nar S. Dalal, Xianglin Shi, Val Vallyathan

"INTRODOCTIONIn an earlier communication 1 from our laboratory it was reported that mechanical crushing of coal and quartz under normal air atmosphere generates of free radicals on the particle surfaces, and that these radicals decay with time, hence pointing to a higher toxicity of fresh dusts in relationship to pneumoconiosis and silicosis. More recently Fubini et al.2 have also reported the detection by electron spin resonance (ESR) of the formation of SiO. and Si-type of radicals from quartz particles crushed under atmospheric conditions. In agreement with earlier ESR studies on single crystals of quartz crushed under high vacuum ( -10-10 torr>3 and subsequent exposure to air,3 and to other gases,4 these radicals were identified2 as being formed by the homolytic cleavage of the Si-0-Si bonds and the reactions of the Si• and SiO- radical with atmosphere. Fubini et al.2 also suggested that these radicals might be involved in the mechanism of the fibrotic action by silica, either by transforming the particle surface into a selective oxidating agent or as an initiator of a sequence of reactions leading to fibrosis. Earlier Gabor and Anca5 bad reported that lipid ·peroxidation caused by free radicals on the silica surface might be involved in the red blood cell membrane damage. Thus far, however, no parallel cytotoxicity, fibrogenicity, and free radica1 studies on a given quartz dust sample have been reported, except for some earlier work from our laboratory.1·6·7 We now present more recent results obtained from parallel cytotoxicity, fibrogenicity, and free radica1 measurements on a freshly made quartz dust. The dust's free radica1 content was measured using ESR spectroscopy while its cytotoxicity potential was estimated via hemolysis. Hemolysis was employed as the toxicity test because it is a widely used method for estimating the potential of a dust for disrupting the cell membrane. 8 The fibrotic potential was followed by measuring the dust-induced lipid peroxidation, using linoleic acid as a model lipid. As discussed below, the results obtained suggest new clues to the mechanism of the quartzrelated cytotoxicity and fibrogenicity. MATERIALS AND METHODSReagentsCrystalline quartz particles with a size range of 0.2-2.5 mm were obtained from the Generic Respirable Dust Technology Center, Pennsylvania State University, University Park, Pennsylvania. These particles were crushed in air to obtain quartz dust samples with particle sizes smaller than 20 microns. We chose to work with a dust with mixed particle sizes, rather than a specific range, as an effort to simulate the mining atmosphere. An agate mortar-pestle arrangement was used for the crushing and grinding because of the close similarity of the structure of agate to that of quartz. Diethylenetriaminepentaacetic acid (DETAPAC) were purchased from Sigma. All other chemica1s were purchased from Fisher or Aldrich.Hemolysls ExperimentsHemolytic activity of silica was measured, following an established procedure,9 as the amount of hemoglobin released from a 2 % suspension of sheep erythrocytes after incubation with 10 mg of silica dust for one hour at 37 °C. The hemoglobin release was estimated via the absorbance at 540 nm using a Gioford spectrophotometer. The procedure was calibrated by substituting the silica dust by a phosphate buffer solution as a negative control (background) and O.S % Triton-X-100 as a positive control (100% hemolysis). The percentage of hemolysis was calculated as follows:"

Jan 1, 1990

By Seth T. Reese

THE INJURY and related employment experience of the coking industry in the United States for 1953 contained in this bulletin are presented under three general sections, as follows: (A) General injury experience: Tables 1 to 9: Contain current and comparable statistics on operating data, number, frequency, and severity of injuries, and major accident agencies involved in the cause of injuries. Data are tabulated for the industry as a whole, for each type of oven, and for the States in which coke is manufactured. (B) Selected injury experience: Tables 10 to 15: Contain comparable injury data covering 5- and 10-year periods on the number and severity of injuries and major accident agencies. (C) Historic injury experience: Tables 1.6 to 19: Contain data on the number and rates of injury occurrence and related employment statistics on the industry from the earliest records through 1953.

Jan 1, 1955

To predict the spontaneous combustion potential of bituminous coals using a simple expression based on an easily acquired coal property. Background Approximately 20% of underground coal mine fires in the United States since 1978 have been attributed to spontaneous combustion. Spontaneous combustion fires in underground mines are most likely to occur in gob area; and are difficult to detect and to extinguish by direct fire fighting methods. Often, sections of the mine or the entire mine must be sealed for long periods, at a great economic loss to the mine operator, mine employees, and the surrounding community. It is conservatively estimated that the cost of scaling a large mine is about $50 million.

Jan 1, 1989

By Oliver Bowles

Marble is one of tile most beautiful and enduring materials employed in the construction industries. Because of its diverse colors, decorative patterns, and varying textures, it has furnished material for artistic architectural design for many centuries. The marble industry is described in some detail in Bureau of Mines Bulletin 106, The Technology of Marble Quarrying, which, unfortunately, is now out of print but may be consul ted at most large libraries. Onyx marble and travertine are discussed in Bureau of Mines Information Circular 6751. The purpose of this paper is to describe the main features of a distinctive group of ornamental marbles known as the serpentine marbles or verde antiques.

Jan 1, 1938

By M. E. Tyrrell

Lightweight basic refractories suitable for use in some sections of the all-basic furnace were developed. Potential advantages of such refractories are lower weight, improved resistance to thermal shock, and less tendency to spall off the working face. Plant trials in positions not subject to heavy loading or severe erosion seem warranted. Forsterite (2MgO.SiO2), stabilized dolomite (2Ca0?SiO2 + MgO), and chrome-spinel [(Fe,Mg)0?(Cr,Al) 031 refractories were fabricated using bubbles as the principal component in the brick mixtures. Bubbles were blown from melts of the basic raw materials as they were tapped from a conducting-hearth arc-resistance furnace. The bubbles were graded, bonded with synthetic Forsterite plus mineralizers, dry-pressed, and fired to temperatures of 1,600° C. or over in a gas-fired kiln. Refractory properties of the bubble brick were compared with those of insulating refractories made by burning combustibles out or dense brick mixtures. Lightweight refractories fabricated of bubbles were one-third lighter in weight than dense bricks of like materials. Their mechanical strength was satisfactory, and their resistance to thermal shock was excellent. In tolerance to open-hearth slag and in resistance to thermal shock, the chrome-spinel bubble bricks wore the best of the refractories tested. Basic refractories of the insulating type were about 40 percent lighter in weight than dense commercial refractories, but they were mechanically weak and not suitable for superduty service.

Jan 1, 1962

By Sam S. Taylor

Subsurface disposal of oil-field brines was practiced in Oklahoma on a limited scale as early as 1925. The technique of subsurface injection has been improved immensely and has been applied with varying success in many oil-producing areas in Oklahoma, and elsewhere. This method of disposal, however, is only one of several methods available to operators of oil-producing properties, but, in contrast with usual methods of handling brines on the surface it eliminates the damaging effect of mineralized water on fresh-water supplies, vegetation, and aquatic and other animal life. Other methods of brine disposal approved by regulatory agencies in some States include (1) impounding in impervious ponds and solar evaporation, (2) controlled diversion into surface waters, and (3) recovery of the mineral salts of the brine. In most States where oil is produced regulatory bodies authorize the use of one or more of these methods of brine disposal. In Oklahoma, for example, the .Oklahoma Planning and Resources Board of the Conservation Commission has been authorized4/ to adopt whatever methods or means may be necessary to prevent contamination by mineralization of all potable waters within the State.

Jan 1, 1942

By Ferron A. Olson

Natural bornite (Cu5FeS4) leached in ferric chloride or in sulfuric or hydrochloric acid solutions with oxygen showed several differences. In ferric chloride 80 of the copper was leached in two stages. The first (30 copper removal) requiring one minute was controlled by mixed kinetics (liquid ferric ion diffusion and chemical surface reaction). The second was controlled by formation of a surface sulfur layer and then diffusion through the sulfur. With oxygen in sulfuric acid reaction was slow and only the first stage was studied. Copper removal had an induction period. The bornite structure disappeared at 12% copper removal (also found with ferric chloride) and covellite formed on the surface with a species inside the particles having an x-ray structure similar to CuFeS2 but with composition Cu3FeS4 (also with ferric chloride). Copper removal was controlled by iron dissolution. Surface iron vacancies filled with Cu+ to give CuS while interior copper dissolution produced Cu3FeS4. Preliminary results with oxygen and hydrochloric acid showed 80% copper removal and sulfur as end products (similar to ferric chloride).

Jan 1, 1982

By Herbert H. Einstein

Instability of rock slopes often occurs in the form of excessive movement of bodies that are bounded by discontinuities. The well known limit equilibrium analysis for wedges and blocks suffer, however, from procedural simplifications and from the basic deficiency of limit eguilibrium analysis--the rigid body assumption. Thus, stability analysis for 2-and 3-plane wedges with a wide range of additional features regarding failure modes and external forces have been developed. The deficiency, due to the rigid body assumption, was corrected by an approach that includes the effects or the in-situ stress field and of the stiffness of discontinuities. The final step in making limit equilibrium approaches more valid was achieved with the method of artificial supports which makes it possible to identify among all possible failure modes the critical one and to determine the corresponding factor of safety. The analytical development includes the creation of appropriate computer codes and routines for programmable pocket calculators.

Jan 1, 1979

By F. D. DeVaney

Metallurgists and coal-washing engineers have used heavy liquids for years in studying the characteristics of ores and coal. By such means true separations can be made between the various specific-gravity increments in the materials examined. To use of heavy liquids has permitted determination of the possible grades of tailings and concentrates by specific-gravity methods on any particular size, and therefore the size to which the ore must be crushed to free the valuable material. The simplicity of float-and-sink separation and the high degree of efficiency attained in the laboratory are factors that commend the method for commercial concentrations.

Jan 1, 1940

By Paul M. Buttermore

As part of a national canvass of water use the Bureau of Mines compiled data on water requirements in the petroleum and natural gas industries for the calendar year 1962, specifically in well drilling, secondary-recovery operations, and natural gas processing plants. Total new water use in the petroleum industry of the United States, excluding refining, was 5.3 billion barrels. Secondary-recovery operations and natural gas processing plants required about 2.5 billion barrels of new water input; each of these requirements was about eight times greater than that for well drilling. Total use, including recirculated water, was 45.3 billion barrels of which 3.4 billion barrels was consumed. The greatest use of recirculated water was for natural gas processing, amounting to 38.2 billion barrels. Projections of total water use show that by 1975, 75.4 billion barrels will be used by the petroleum industry, of which 10.2 billion barrels will be new water. By 1985, the total use requirement will be 92.8 billion barrels, of which 13.1 billion barrels will be new water.

Jan 1, 1966

By Paul M. Buttermore

As part of a national canvass of water use the Bureau of Mines compiled data on water requirements in the petroleum and natural gas industries for the calendar year 1962, specifically in well drilling, secondary-recovery operations, and natural gas processing plants. Total new water use in the petroleum industry of the United States, excluding refining, was 5.3 billion barrels. Secondary-recovery operations and natural gas processing plants required about 2.5 billion barrels of new water input; each of these requirements was about eight times greater than that for well drilling. Total use, including recirculated water, was 45.3 billion barrels of which 3.4 billion barrels was consumed. The greatest use of recirculated water was for natural gas processing, amounting to 38.2 billion barrels. Projections of total water use show that by 1975, 75.4 billion barrels will be used by the petroleum industry, of which 10.2 billion barrels will be new water. By 1985, the total use requirement will be 92.8 billion barrels, of which 13.1 billion barrels will be new water.

Jan 1, 1966

By James L. Ash

This report contains the results of a technical and economic evaluation of conceptual systems for the underground mining, rubblization; and in situ retorting of deep oil shale deposits. Study efforts were first directed towards evaluation of the applicable geology, associated minerals, rock mechanics, in situ retorting, access mining, ventilation, rubblization, safety, and environmental impact factors. Conceptual systems were synthesized and then evaluated against these factors from both a technical and limited economic viewpoint. The results of these evaluations were then analyzed 'and, based upon this analysis, the following two systems were selected for further study: System II: Room and Pillar-Vertical Drill and Blast System IV: Tunnel Boring-Horizontal Ring Drill and Blast Due to the large number of variables to be considered, a computer program was developed and utilized to provide data for the cost trade-off studies and economic analysis. Results of the early computer runs indicated the value of the tool available in the computer program and led to an extension in the contract to determine the sensitivity of the systems to several of the more apparent significant variables. These results in turn led to a refinement in the design assumptions and a better understanding of the technical and economic options available to an owner-operator of a Vertical Modified In Situ Shale Oil Extraction System. This report is submitted in fulfillment of the requirements of Contract Number S0241073 by Fenix & Scisson, Inc. to the Denver Research Center, United States Department of the Interior, Bureau of Mines. Work was completed as of November, 1976.

Jan 1, 1976

By H. Miller

In recognition of the need for a portable low-profile hard rock crusher, the Bureau of Mines sponsored the development of such a unit capable of moving up as the face advances. By allowing primary ore reduction at or near the mine face, the advantages of conveyor haulage From the face as demonstrated in soft ore and coal mines, could be realized for hard rock Brines as well. This report presents the results of a development and testing program for such a portable low-profile crusher, designed by Eagle Crusher Company and called the M44. The unit has an extremely low vertical profile considering its size and capacity. The crushing jaws, which form the crushing lumber, are inclined, with the lower jaw mounted for eccentric movement relative to the stationary upper jaw. This provides efficient crushing while also forcing material through the crushing chamber. As a result, the inlet feeder can be disposed horizontally. To facilitate correct processing of different materials, the size of the discharge opening and the action of the movable crushing jaw are variable. The unit also incorporates a feeder hopper and discharge conveyor that provides for efficient ore handling through the machine. Tests demonstrated the M44 Crusher's high capacity, efficiency and reliability. During testing, it crushed over 120,000 tons of materials of up to 32,000 psi compressive strength at production rates in the 200-350 tons/hour range. The unit operated smoothly under simulated low-headroom conditions, and Proved readily transportable.

Jan 1, 1983

By H. G. Wolfhard

The propagation of explosions through short cylindrical channels has been investigated by the Bureau of Mines. In the experimental apparatus set up by the Bureau, a single such channel formed a connection between a small explosion vessel in which a gaseous explosion was initiated and a larger, partly enclosing, explosion vessel filled with suitable gaseous mixtures; the larger vessel permitted observation to determine if an explosion was induced therein by mass, energy, and species transfer through the channel, as a result of tie initial explosion, It has been found that transmission of flame through to channel is not an essential to induce the second explosion, for hot gases from an extinguished explosion are able to ignite cold combustible mixtures in the larger vessel. The schlieren patterns of flames or hot burned gases emerging from a channel into the explosion chamber were photographed. These show, in most instances, that vortexes of hot gas ejected from the jet into the cold explosive mixture are responsible for ignition. The study has practical significance in problems of rendering electrical equipment safe for use in potentially flammable atmospheres, INTRODUCTION The propagation of flames through cylindrical or annular channels has practical importance in flameproofing electrical equipment and for flame traps. Much practical work has been done to determine the minimum safe breadth of flanges and the maximum safe gap between the flanges that will permit venting an electric motor without allowing flames to pass.

Jan 1, 1959

By D. Harrington

Seldom, if ever, has any mining hazard presented itself that some method has not been devised to control it to some extent; the degree of success of such control depends largely upon the intensity of desire to prevent suffering, injury, and death. The economic saving to be realized and the more definitely this is realized by all concerned, the more quickly and effectively will the hazards be handled is an important incentive to prevention of accidents. Preventing coal-mine explosions is by no means a complex problem; all that is necessary is sensible, conscientious, sustained effort. The fact that explosions can be prevented has been well-demonstrated by the record of the post few years; the average annual death toll from explosions for the 5 years 1906-1910 was 438, and for the 20 years prior to 1929 it was 265: during the past 4 years an average of only 32 deaths per year resulted from this cause, although the annual production during that time varied but slightly from that of 1906-10. This is a truly remarkable reduction, and if other types of mine accidents had been reduced in the same ratio only about 300 would be killed annually in our mines instead of the nearly '1,300 killed in 1936 and the approximately 2,000 killed annually for many years. Although frequency of occurrence of explosions has not lessened greatly during the last decade, their severity decreased markedly, which would indicate that effective means are being taken to prevent the spread of explosions, even though ignitions and their causes are not being handled nearly as effectively as they might or should be handled. Several large coal-producing States, which in the past have experienced numerous disastrous explosions, have been free from such disasters for continuous periods as long as 8 years in the relatively recent past. The application of rock dust to underground surfaces has been an important factor in preventing widespread explosions; some of the mast dangerous mines have been rock-dusted fairly adequately, and this has been amply repaid in the reduced severity of explosions, as heretofore indicated; however, many have applied rock dust apparently without giving much consideration to the amount required to prevent

Jan 1, 1938

By Floyd G. Anderson

A study was made of the effectiveness of dust-control methods being employed in connection with continuous-mining operations. Airborne dust exposures of workmen and dust loadings of return air were determined for six types of continuous-mining machines. The conditions required for control of dust exposure are summarized and include ventilation of the working face by an exhaust system. Return-air dust loadings ranging up to 13 pounds per hour are reported.

Jan 1, 1963