Search Documents

By R. Stefanko

This first Annual Report covers the work on Contract No. H0377043 "Cable for Face Equipment", from August 1, 1977 to July 31, 1978. It reports the progress in the three areas of over-and short-circuit protection, cable ampacity research and cable couplers. Field trips have established many interesting facts related to circuit breaker settings and cable size. For example, the determination of cable sizes depends on the RMS duty cycle current determined by a particular piece of equipment, but the actual selection of the cable to be used is often a function of the maximum allowable circuit breaker instantaneous settings as specified in Title 30. In order to avoid nuisance tripping as a result of instantaneous starting current field, laboratory and analytical studies are being conducted to determine proper settings and cable sizes Also an extensive program has been established to monitor the performance of high voltage cable couplers and determine their modes of failure. Various equipments are being designed for laboratory testing, and an extensive reeled cable experiment is also under way.

Jan 1, 1978

By E. L. Rawlins

Systematic leakage surveys of natural-gas transmission lines not only aid in the conservation of gas, but can be made to show direct financial returns of large magnitude. 1. Such surveys reveal the actual leakage from the lines, and indicate repairs to be made in order, to eliminate unnecessary waste. 2. Tests on lines, after repairs are made, show the actual saving that has been accomplished. 3. Tests on newly constructed lines reveal the presence of leakage that should be eliminated before the lines are put into service.

Jan 1, 1926

By Wesley T. Holmes

This report describes the first phase of an investigation aimed at obtaining a wider knowledge of the problems involved in smelting titaniferous magnetites. Liquidus temperature measurements were made on selected slag compositions in the titania-alumina-silica-calcia-magnesia system. Both the melting-holding-quenching method and the hot-stage microscope method were used in the tests. Liquidus temperatures of slags studied ranged from 1,217° to 1,667° C. The lowest liquidus temperature of the slags occurred when the difference between CaO plus MgO and Si02 was less than 12 weight-percent. Liquidus temperatures were also lowered when Si02 was substituted for Ti02 plus Al2O3 when CaO and MgO levels were held constant. Improved methods for the measurement of liquidus temperatures on very small samples are described.

Jan 1, 1968

By Masami Hayashi

The Bureau of Mines estimated the cost for ,3 uranium ion-exchange recovery system using five grades of 17.0, leach solution producing 815,570 pounds of U 0? per year from an ammonium bicarbonate in situ leach solution. The system flowsheet consisted of four unit operations: (1) Multiple-compartment ion-exchange (MCIX) absorption; (2) MCIX elution; (3) precipitation of the uranium as yellow cake, filtering, calcining, and packaging; and (4) waste disposal. The total fixed capital cost of a system treating 2,000 gallons per minute of 0.1-gram-per-liter-U308 leach solution was estimated as $6,888,000. For n basic case of an MCIX system depreciating in 9 years, unit production cost of U308 was $3.51 per pound. A decrease in feed solution grade from 0.[4] to 0.03 gram per liter increased the production cost exponentially. Shorter depreciating periods significantly increased the production cost particularly for the lower grade feed solutions.

Jan 1, 1979

By R. Barany

This report contains the results of experimental work conducted by the Bureau of Mines to obtain the heats of formation at 298.15° K. of analcite, dehydrated analcite, lawsonite, anorthite, hexagonal anorthite, and leonhardite. Thermodynamic data for these minerals have applications in ceramics, extractive metallurgy, and particularly in geochemistry. Except for data on anorthite, no previous similar data existed. The present results will be a substantial aid in deriving the temperature-pressure-equilibrium relationships among these minerals. The heats of formation were determined by solution calorimetry, with hydrofluoric acid as the reaction medium. The results were expressed both in terms of the constituent oxides and in terms of the constituent elements. The heat of formation data were combined with related entropy values to obtain the free energies of formation at 298.15° K.

Jan 1, 1962

By F. W. Wood

Ingots of zirconium and other highly reactive metals such as titanium and hafnium produced by the consumable-electrode arc-melting process require conditioning before forging or rolling. A nondestructive, arc-conditioning technique has been developed as a substitute for lathe conditioning. The technique employs en electric arc under an inert atmosphere to fuse surface metal on the sidewalls of ingots without seriously affecting the general quality of the ingots. Advantages of the practice are Increased yields, lower accumulation of inferior scrap, and actual cost savings. The work cited in this report was done on zirconium. INTRODUCTION The consumable-electrode arc-melting process as practiced at the Bureau of Mines3 4/ has proved to be a technique for producing sound, homogeneous, commercial-size ingots of zirconium and its alloys. Ingots produced by this process, however, have as a characteristic a layer of partly fused metal on the sidewall to a depth of 3/16 to 3/8 inch. To prevent extension of surface imperfections during forging, the ingots are ordinarily conditioned by removing defective material in a lathe. If the metal were less reactive or the requirements less severe, the machine chips could be recycled and remelted. However, zirconium, being so oxygen sensitive, is contaminated by merely being machined despite extensive cooling of the tool bit. Further, being contaminated with oxygen, the chip metal upon remelting is 10 to 25 Brinell-hardnese numbers harder than the ingot from which it was machined. For this reason, the ingot specifications for naval reactor use have prohibited remelting machine chips, except as required for starting pads. Again, were zirconium less costly or less in demand this ever-increasing pile could be burned to oxide and recycled through the Kroll sponge process. Economics do not favor this, as melting feed stock has an estimated increase In value over oxide of about $8.80 per pound of contained zirconium. The efforts of the Bureau to solve the problem have been directed along two lines: To reduce the contamination of the machine chips produced and to reduce the quantity of the chips produced. This paper presents the technique developed to reduce the quantity of chips produced by arc-conditioning the remelted ingot.

Jan 1, 1955

By M. D. Aldridge

This document reports the results of a two-year research effort aimed at improving communication systems used in coal mines. This work was conducted under a program whose original goal not only involved the development of practical and effective electronic systems for operational communications, but also for monitoring, at a central location, remote instruments at key positions in a mine. About half way through the originally proposed three year effort, the program was redirected to phase out the communication effort at the end of two years and to concentrate the program" resources on the investigation of new monitoring system concepts developed by this research. Thus, the work reported here is incomplete relative to the originally pro- posed program. However, the work was carried to the point of providing sufficient evidence to aid in the comparison of certain new communication concepts. For the concepts chosen for this study, the work was stopped short of hardware development and field testing, Several reports in the form of Master's theses and a Doctoral Dissertation have resulted from this research. They each report in considerable detail the results of several individual" contributions to this program. In preparing this report, an attempt has been made to provide a complete description of the significant results but with- out burdening the reader with the minute details. These more detailed reports are referenced heavily for the convenience of those interested. PRESENT COMMUNICATION METHODS Two types of communication systems are presently used In coal mines. They are: 1, Various forms of telephone systems, and 2. Carrier current radio systems using the trolley line as the interconnection circuit. Carrier current radio is used almost exclusively for control of rail trafflc by the dispatcher. Almost all other communication uses the telephone system, Telephone lines generally extend to areas where trolley lines are not present such as the outside offices and warehouse. Therefore the telephone system provides the primary means of voice communication. Telephones - Telephone systems employed in American coal mines fall into three categories. 1. Paging type telephone systems - these systems have individual stations which use battery powered transistor audio amplifiers to boost signal levels for normal communication. When in the page mode,

By Mark Sanders

This report describes an experiment which was conducted to compare the relative bumping hazard of a low and high profile hard hat (helmet) in a low seam mining environment. The study was specifically designed to assess the effect of lowering the helmet profile on frequency of head impacts in an underground low seam coal mine simulator. This involved subjects performing four common low coal mining tasks wearing the low and high profile helmets in the low seam simulator (36" and 48? heights). The results of the study indicated that a low profile helmet could reduce bumping frequency in underground low coal approximately 25%, and as much as 80% on selected tasks. It was beyond the scope of the study to measure the impact force, thus it was not possible to estimate the effect of the low profile helmet on severity of impacts underground. The research team recommended that a more extensive investigation be made of head injuries experienced in low seam mining (both underground and surface) with the objective being to assess the impact of a low profile helmet on total head accident exposure.

Jan 1, 1980

By Steven W. Schmauch

The U.S. Bureau of Hines conducted e mineral resource survey of approximately 232,000 acres in part of the Humboldt National Forest, Nevada, during 1989. About 7S percent of the study area was covered with mining claims. About 1,800 samples were collected end analyzed for 16 elements. Geologic structure, including thrust faults, is the most important factor in the localization of mineral deposits in the study area. The Independence mine (formerly Jerritt Canyon), Big Springs, and Wood Gulch are the most well known active properties, all developed on large, low-grade, disseminated gold deposits. These deposits have produced almost 3 million ounces of gold and are known to contain more than 8 million ounces of gold. At least 10 barite deposits in the south end of the range have had significant past production and contain 0.2 million tons of resources. Numerous precious and base metal targets have been identified and in some cases quantified during this study.

Jan 1, 1992

By M. John Brodie

This report reviews the regulatory environment as it pertains to tailings management and disposal from mining operations, excluding coal and placer gold operations, in the state of Alaska. It is based on the EPA's staff position on an effective program to regulate mining wastes as presented in the May, 1990 Strawman II document, The unique conditions which occur in parts of the state, including a fragile environment, high seismicity and permafrost, are identified. The special waste management practices which are necessitated by these conditions are delineated. The report provides a detailed outline of the current technologies that are suitable for designing, constructing, operating and closing a railings disposal facility to meet environmental protection objectives. Cost implications to the mining industry of potential regulatory actions, such as the degree of groundwater protection are examined.

Jan 1, 1992

By Virginia E. Gleason

In this report, recommendations are made for programs to develop workable techniques to stop or prevent acid mine drainage formation in those underground coal mines where acid production could take place. These recommendations include development of mine closure technology, development of surface water infiltration control procedures, study of the effect of roof collapse on mine water characteristics, evaluation of the long-term effects of flooding underground mines above drainage, investigation of the effectiveness of section sealing in active mines, development of a simple model for predicting mine water quality and quantity, preparation of a manual on mine drainage abatement procedures, and development of a program to disseminate information on mine drainage abatement to the coal industry. These recommendations are based on an in-depth evaluation of information acquired over years of research on acid mine drainage formation, on numerous laboratory and field studies of methods of preventing or minimizing acid mine drainage formation, and on review of the geological, hydrological, and mineralogical factors involved. There are 772 references.

Jan 1, 1978

By L. W. Brandt

The Bureau of Mines, as part of its mission to effect pollution abatement, conducted research to study various means of dewatering Florida phosphatic clay wastes and reclaiming mined lands. The work was done in cooperation with 10 Florida phosphate companies. During this work, a novel technique to effectively dewater phosphatic clay wastes was developed. The solids contained in the clay waste slurry are slowly compressed by moving wire mesh screens through the system. In a typical application, the screens were moved downward, compressing solids ahead of the screens. The rate of movement of the screens is an important variable in the process. It is believed that the moving screens distort the gel structure of the phosphatic clay system and cause the release of water. Samples of 18 clay wastes, including a high-grade attapulgite from beneficiation plants of the Florida phosphate field, were studied using the method. Typical samples were concentrated from initial solids of 4.7 and 11.9 percent to 16.8 and 25.2 percent, respectively, in 3-1/2 days. The high-grade attapulgite sample was dewatered from 2.7 percent solids to 13 percent solids in the same period.

Jan 1, 1980

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag compositions. The present report deals with the CaF2-Y203 system for which solidus and liquidus temperatures and solid solubilities were determined. The information is presented as the phase diagram. All specimen compositions were blended from high-purity materials and encapsulated in Mo or Pt20Rh prior toheat treatment. Liquidus temperatures were determined by ceramographic examination of heat-treated and quenched specimens. Solidus temperatures were determined by differential thermal analysis and by electron microprobe analysis of quenched specimens. Terminal solid solubilities were derived by parametric methods. The peritectic system was found to be pseudobinary due to the formation of yttrium oxyfluoride at temperatures near the liquidus. The peritectic point occurs at 7 mole pct Y203 and 1,438° ± 5°C. The terminal solid solubility of Y203 in CaF2 decreases from 7 mole pct at 1,438° C to 1 mole pct at 1,100° C, and the solubility of CaF2 in Y203 decreases from 9.5 to 7 mole pct over the same temperature interval.

Jan 1, 1970

By George T. Faust

The petrographer engaged in examining the products resulting from the beneficiation of ores and rock minerals is constantly required to develop new means and methods of assaying microscopically the results of such operations. From time to time investigators have published descriptions of apparatus that have aided in solving problems in processes f physical separation. Thus, in 191.9, Coghill and Bonardi 31 published a paper covering the application of the binocular microscope and camera lucida to the microscopic analysis of pulverized ores. Similar work has been published by Schneiderhohn 4/, Schwartz 5/, and Head and his associates6/, 7/, 8/. The present paper goes further and considers application of the polarizing comparison-microscope to problems directly concerned with mineral dressing where it is desirable to compare analogous products, and in addition it suggests new uses in various related fields. This work was conducted under the cooperative agreements of the Southern Experiment Station of the Federal Bureau of Mines and. the University of Alabama.

Jan 1, 1940

By C. E. Hennig

On January 1, 1961 there were 311 petroleum refineries in the United States with a total crude-oil throughput capacity of slightly more than 10 million barrels per day, according to the Bureau of Mines' annual survey. Compared with a year ago, this represents net increases of one in the number of plants and 109 thousand barrels per day in total capacity. Contributing to this increase was the completion of two new plants, one in Hawaii and another in Michigan, during the year. At the beginning of 1961 the industry was building facilities which will increase this overall crude capacity by 36,500 barrels per day. As part of its building program, it was also replacing 329,000 barrels per day of its present capacity. Of the total 10 million barrel per day installed capacity, the industry reported 380,000 barrels per day as being shut-down on January 1, 1961. This included 11,500 barrels per day considered inoperable without extensive reconditioning.

Jan 1, 1961

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 Barry L. Warner

This program involves testing to determine whether a fire hazard exists when the exposed wood surface area of timber in a mine passageway equals 40 percent of the surrounding strata surface, excluding the sill. Twelve full scale fire tests were conducted in a simulated mine passageways, using kerosene pan fires as the ignition source. The tests included three timber sizes, plus one test with roof lagging, two wood types, plus one test with treated timbers, and two ventilation air velocities. The results show air velocity to be an important factor in the occurrence of flame propagation, and that the 40 percent surface area ratio of wood to surrounding strata appears to b0. a valid criteria for fire safety at 150 fpm, but not at 350 fpm.

Jan 1, 1975

By R. K. Koch

The vapor pressures of liquid titanium and liquid platinum were studied under the Bureau of Mines program for the determination of thermochemical data on the transition elements. Beating was done in a 2-kw electron-beam furnace with a water-cooled copper crucible to contain the melt. Temperature was measured with a disappearing-filament brightness pyrometer. The vapor pressure data for liquid titanium in the range 2,008° to 2,379° K are represented by the least-squares derived equation [log p (atm) = 6.268 - 22, T] Two series of determinations were made on liquid platinum. Results of the first series are expressed by the least-squares derived equation [log p (atm) = 8.240 - 30,460T] for the range 2,0860 to 2,4200 K. Results of the second series are expressed by the least-squares derived equation [log p (atm) = 7.795 - 29,580 T] in the range 2,045° to 2,442° K. Third-law evaluations of each series gave mean standard heats of sublimation of 112.4 kcal/mole, 133.3 kcal/mole, and 133.8 kcal/mole for titanium first series on platinum, and second series on platinum, respectively. Second-law heats of sublimation and equations for heats, free energies, and entropies of vaporization were obtained from sigma plots of each data set.

Jan 1, 1969

By Fredrick L. Johnson

No mineral resources were identified during the investigation of the White Cloud-Boulder RARE II area. Only a few claims have been located in the area and only two workings were found. However, there has been considerable exploration and mining activity near the RARE II area. Sand and gravel resources are abundant but similar deposits occur closer to market areas. There are no known coal, oil, or gas deposits. Most of the RARE II area is underlain by volcanic rocks. The likeliest host rocks for metallic minerals are the metasedimentary rocks exposed in the south part of the area; there is potential for zinc and silver resources at a prospect in that part. Traces of scheelite and powellite were observed in the Kent Peak-Ryan Peak area along hair-line fractures in calcareous country rock. While no significant concentrations of the minerals were found, their presence, a northwest alignment of prospects with similar deposits, and an abundance of dikes near the deposits, suggest that the intrusive system (Summit Creek stock) exposed near the head of Little Fall Creek may extend to the northwest under the RARE II area.

Jan 1, 1983

The production of harmful pollutants from coal mines and/or from coal and associated strata has been a recognizable fact in the United States for over two hundred and seventy years. In 1698, Gabriel Thomas observed(l) that the colored water flowing from streams in this country was similar to that which flowed from the coal mines in Wales. Hence, water pollutants such as acid were being produced before any known coal mines were operating in this country. The coal mining industry has contributed to the increase of pollution by exposing large amounts of sulfide materials that enable the reaction of water, oxygen and sulfur containing materials to form acid. A map of the United States coal fields can be seen on Figure 1. The anthracite regions of Pennsylvania, although small when compared to the total reserves, have produced some of the country's major water problems. The map indicates the extent of bituminous reserves of the Appalachian and midwest regions. Also evident are the bituminous, subbituminous and lignite coal reserves in the west which have recently come into greater demand. Acid mine pollution is encountered in numerous states, but the major problem is found in the Ohio, Susquehanna, and Potomac River basins.(2) Most coal beds contain some sulfur which may be in the inorganic, sulfate, or sulfide form, and thus have the potential to produce sulfuric acid. However, much of the strata that overlays the coal beds also contains acid neutralizing materials. Therefore, the amount of acid produced depends upon the amount of both acid and alkali materials that dissolve in the water in any given mine. The common sources of sulfurous material in the seam or surrounding rock are generally called sulfur balls or "nigger heads" by the miners. Sulfur balls that have been observed(3) seem to be equally divided between those containing sulphuritic iron capable of producing sulfuric acid upon oxidation and those that are primarily calcium carbonate. It has been observed in many instances that two types of water, acid and alkaline, are being produced in the same mine. A study of the geological strata and a survey of subsidence, faults and sulfur balls will usually give some indication of why this happens. The reaction of pyrite (FeS2) with oxygen and water to form ferrous sulfate (FeSO4) and sulfuric acid (H2SO4) by a series of complex chemical interactions is well documented but not well understood.(4,5) However, it is well known that the reactions to form the acid cannot occur unless all three constituents are present. Since pyrite is inherent in most coal seams and air is needed to sustain the miner, the most logical answer is to eliminate water infiltration into the mine, or to remove it from the mine before acids can form.

Jan 1, 1970