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By Bernard Baum

Combined preservative/fire retardant systems were pressure impregnated into Douglas fir and Ponderosa pine samples and evaluated for decay, flammability, and mechanical properties. The objective of the evaluation was to identify cost-effective systems for use with mine timber, and to provide an information and data base from which Federal code regulations could be established. Thirty systems, based on combinations of commercially available preservatives and fire retardant impregnants and coatings, were applied to Douglas fir samples and evaluated for decay and flammability. The ten most promising systems were ap¬plied to both fir and pine and reevaluated for decay and flammability before and after water leaching. The five best systems were given a thorough laboratory evaluation using both pine and fir. Evaluations included flame spread, smoke density, toxic gases, decay, compressive strength, flammability after artificial weathering, and cost. All systems had acceptable toxic gas levels and smoke densities, but flame spread was only borderline acceptable for most of the samples tested. A trade-off analysis showed Acid Copper Chromate/Fyrprufe with Albi-107A/144 intumescent paint and Koppers NCX to be the-best systems. Recommendations are made for further large-scale testing using the two best Systems.

Jan 1, 1978

By A. Landsberg

Kaolinitic clays are potentially a vast domestic resource for aluminum. Utilization of this resource could decrease or eliminate the nearly complete dependence of the United States on foreign raw materials for this important metal. Furthermore, processing of clay to aluminum through anhydrous chloride metallurgy could reduce the high electrical energy requirements of the conventional Hall-Heroult aluminum reduction process. Several anhydrous chloride processes have been proposed; however, unresolved technical problems have prevented their commercialization. In particular, an acceptable chemical means has not been found to extract aluminum from clay as a highly pure anhydrous aluminum chloride. This Bureau of Mines report identifies and discusses the important chemical problems involved in achieving an acceptably rapid, self-heating, selective chlorination reaction and the subsequent separation of iron chloride byproduct from the anhydrous aluminum chloride.

Jan 1, 1983

By O. Q. Leone

A processing unit was developed for the complete cleaning of titanium alloy chips. The process uses solvent degreasing, magnetic separation, and anodic solution of nonmagnetic impurities in 10 weight-percent sulfuric acid. Vacuum arc-melted ingots weighing approximately 10 pounds each were prepared from cleaning chips according to ingot specifications.

Jan 1, 1973

By Larry Joe Linley

The Department of the Interior, Bureau of Mines is reviewing explosion protection methods for use in gassy coal mines. This performance criteria guideline is an evaluation of three explosion protection methods of machines electrically powered with voltages up to 15 000 volts AC. A sufficient amount of basic research has been accomplished to verify that the explosion-proof and pressurized enclosure methods can provide adequate explosion protection with the present state of the art up to 15 000 volts AC. The routine application of the potted enclosure as a stand alone protection method requires further investigation or development in order to clarify performance criteria and verification-certification requirements. An extensive literature search, a series of high voltage tests, and a design evaluation of the three explosion protection methods performed at White Sands Test Facility indicates that the explosion-proof, pressurized, and potted enclosures can all be used to enclose up to 15 000 volts AC, if the performance criteria and verification-certification requirements recommended in this guideline are implemented.

Jan 1, 1982

By W. W. Fowkes

The Federal Bureau of Mines examined a low-temperature tar obtained from a small-scale commercial unit for carbonizing North Dakota lignite for products that might be important to the economic processing of the tar. Tie tar may be divided into three distinct parts: (1) Tar acids, 45 volume-percent; (2) tar bases, 1 volume percent; and (3) neutral compounds, 54 volume-percent. It has a boiling range of approximately 150° to 380° C. (the decomposition temperature) and yields 18 weight-percent as hard pitch. The tar distillate up to 365° C. may be separated as: (1) Tar acids, 48 volume-percent; (2) tar bases, 1 volume-percent; and (3) hydrocarbons, 51 volume-percent. The tar-acid distillate, boiling to approximately 265° C., was characterized in some detail; the neutral fractions and the tar bases were less thoroughly examined. In general, as might be expected of a primary low-temperature tar, the lower boiling fractions are less in quantity compared with the usual high-temperature tar. The homologous series of each major class appears to be rather complete, although some components are present in very small amounts. The tar is quite unstable thermally, and might be more conveniently processed by extraction methods rather than by distillation procedures. The neutral fraction of the tar is highly aromatic, and might be considered as base stock for the production of liquid fuels.

Jan 1, 1961

By P. G. Pigott

This Bureau of Mines laboratory research demonstrated that building bricks meeting ASTM specification C62-66 for grades SW and MW of FBS-type bricks can be produced from waste copper mill tailings. Waste tailings from accumulations at Magna, Utah, Anaconda, Mont., and Hayden, Miami, and San Manuel, Ariz., were dry-pressed into bricks, and the products were tested in accordance with ASTM Designation C67-66 on sampling, and testing of brick. An evaluation derived from pilot-plant production of similar brick at the Coal Research Bureau of West Virginia University indicated the production cost to be about $34 per 1,000 bricks. Utilization of such mill tailings on a commercial scale would eliminate the need for digging new pits for brick raw material production, conserve natural resources, and simultaneously remove potential sources of air pollution.

Jan 1, 1971

By D. Bienstock

As part of the development of the hot-carbonate scrubbing process by the Bureau of Mines, the corrosion rates of steel in boiling solutions of potassium carbonate saturated with carbon dioxide and hydrogen sulfide were determined, and the effectiveness of various inhibitors was evaluated by Bureau researchers. The highly corrosive solution of carbonate saturated with carbon dioxide can be inhibited with a 0.2-percent concentration of either potassium chromate or sodium metavanadate. Solutions of carbonate saturated with carbon dioxide and hydrogen sulfide are mildly corrosive, 0.01 inch per year. Complete absence of corrosion is obtained with 0.2 percent sodium metavanadate or 0.15 percent vanadium pentoxide. Oxidizing inhibitors such as potassium chromate are destroyed in the alkaline sulfide mixture, N-alkyl trimethylene diamines, at a concentration of 0.1 percent, lower the corrosion rate to about 0.005. Sodium metasilicate, at a concentration of 0.6 percent, completely inhibits the corrosion but may deposit free silica in the system. Commercial cladding materials such as the epoxy coatings also prevent corrosion.

Jan 1, 1962

By Floyd C. Bossard

Major air-cooling facilities have been installed and are operating underground in U.S. copper mines (at Butte, Montana and Superior, Arizona), South African gold mines, European coal mines, Zambian copper mines, Kolar gold mints in India, Coeur d'Alene mines of Idaho, plus other locations. Mining districts that utilize spot cooling and local air-cooling facilities would increase the above listing many times. The principal objectives of underground mine air cooling systems are to; 1. Extract heat and water vapor from the mine air and provide for their removal from the mine via (a) water pumped to surface or (b) discharged mine exhaust air. 2. Provide acceptable artificial ambient conditions for efficient working mine development and production areas. 3. Recondition used air, thus supplementing the limited mine ventilation balance. In deep South African gold mines, when rock temperatures exceed about 105°F, cooling of underground air becomes necessary for the poorly ventilated sections of the mine. By U.S. standards, air conditioning in poorly ventilated mines usually commences when the virgin rock temperature exceeds 100°F. On the other hand, well ventilated deep vein-type mines in the U.S. have been able to forego general cooling of mine air until the mines have been extended to such depths that the virgin wallrock temperatures have exceeded 115° - 120°F. It must be noted that spot-cooling of selected development headings may be required in many mines where rock temperatures exceed 100°F. Such local air-cooling practices permit the driving of long headings for exploration or extended development prior to holings which result in establishment of primary ventilation circuitry. The following summary reports on current practices of cooling and dehumidifying mine air. General system descriptions with important details will hopefully permit the reader to gain an understanding of the subject. A list of references is provided for this serious investigator who desires a more thorough knowledge-base and who is responsible for the design of a mine air-cooling system.

Jan 1, 1973

By T. F. Anstett

The Bureau of Mines investigated the availability of platinum from known major deposits in market economy countries. Fifteen of these deposits contain demonstrated resources totaling 302 million troy ounces of platinum. Detailed geologic, engineering, and cost evaluations were performed on each deposit to determine its potential for platinum production. There are large amounts of demonstrated platinum potentially available from market economy deposits that were not analyzed owing to lack of adequate data or to technological limitations. These include 297 million troy ounces contained in the UG2 and Platreef of the Bushveld Complex, South Africa. This analysis indicates that about 11 0 million troy ounces (2.3 million ounces annually) of platinum are potentially available at the January 1980 producer price of $420 per troy ounce, nearly all from South Africa. An additional 85 million troy ounces occurring in Zimbabwean deposits would become available only through more than a quadrupling of that price. In order to meet projected world demand of 3.5 million troy ounces in 1990, platinum price may have to increase. Only one domestic deposit, the Salmon River in Alaska, is capable of producing platinum at $420 per troy ounce. Regardless of price, at assumed production capacities, domestic deposits could supply less than 10 percent of annual U.S. requirements.

Jan 1, 1982

By I. L. Nichols

The Bureau of Mines is investigating vanadium recovery from various domestic resources. A low-grade carnotite ore sample containing 0.34 pct V20S and 0.04 pct U30S was leached, and the results were compared with those of similar leach tests using a mill-grade sample containing 1.26 pct V205 and 0.19 pct U308. Experiments on the two ore samples included agitation leaching, pugging, salt-roast leaching, and autoclave leaching. None of the leaching methods investigated showed any significant advantage over another except autoclaving, which reduced the leach time but at the expense of greater acid consumption. Typical of the experimental results attained are the data gathered from the agitation leaching tests. Agitation leaching of the mill-grade ore with 100 lb/ton H2S04 resulted in extractions of 94 pct U308 and 33 pct V205. To increase the vanadium extraction from 33 to 91 pct required concentrations of 300 lb/ton H2S04 and 10 lb/ton NaC103. Complementary agitation leach tests on the low-grade ore required 200 lb/ton H2S04 to extract 94 pct U308, and 300 lb/ton H2S04 and 10 lb/ton NaC103 to extract 90 pct V205.

Jan 1, 1983

By L. B. Pankratz

Enthalpies above 298° K were determined for AgCl to 1,400° K and for AgBr to 1,200° K by copper-block calorimetry. Before melting, both compounds showed an anomalous increase in enthalpy, an effect associated with lattice defect formation. Melting points and heats of fusion were determined to be AgCl, 730° K and 2,945 cal/mole; AgBr, 700° K and 2,030 cal/mole. The heat capacity of both melted substances decreased with increasing temperature over the entire liquid ranges investigated. Enthalpies above 298° K were tabulated at even temperatures along with derived entropy increments and heat capacity values. The results were combined with the known heats of formation and entropies at 29.8.15° K to obtain values of the heats and free energies of formation over the range 298.15° to 1,400° K for AgC1 and 298.15° to 1,200° K for AgBr.

Jan 1, 1970

By Carl Fisher

A microseismic roof fall warning system was field tested in Western and Eastern coal mines in the United States to better define the capabilities and limitations of the microseismic method in predicting roof fall Microseismic event and energy type data were obtained and documented for twenty-three coal mine roof falls. Field test results indicate that both the microseismic event and energy methods, as applied in this development effort, have a high probability for successful application in a commercially practical roof fall warning system. Based on the results and experience obtained during field testing, a commercial prototype microseismic roof fall warning system was designed and constructed. Although it was the intent of the program to field test the commercial prototype system, delays in equipment fabrication and contract time limitations did not permit field testing.

Jan 1, 1980

By G. W. Jones

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

Jan 1, 1933

By Louis Schaffer

This report characterizes several coal Dine mobile equipment operator populations with respect to age, mine experience, machine operator experience, and training. The information is used to demonstrate a method of normalizing the injury data collected by the Mining Enforcement and Safety Administration-Health and Safety Analysis Center.

Jan 1, 1977

By W. W. Odell

"It has long been recognized that coke is a more desirable fuel than bituminous coal in water-gas apparatus of present design, but still considerable headway has been made in the use of the latter fuel as a substiaute for coke. This is particularly true in the Central States where the supply of high-grade coke has been very limited and uncertain during the past few years, and where coking coals of low sulphur content were available in quan¬tities. In fact, with, the present difference in price of coal and coke, it is possible to realize a marked saving when using a coking bituminous coal as generator fuel.Difficulties have been encountered in the use of such fuel, but they have, to a large extent, been overcome. One of the chief obstacles in the use of the more general utilization of bituminous coal for water-gas manufacture, is the fact that, with normal operation, the capacity per unit of time is reduced. This of course is a serious problem for plants operat¬ing at capacity with coke fuel. However, this difficulty can, to a large extent, be remedied by a changed method of operating, and can be entirely remedied by a combination of the latter with a change in the design (or proportions) of a water-gas set. The preceding statement, the reader will understand, refers more particularly to a carburetted water-gas set.In the manufacture of water gas from coke, present practice requires that for continuous 24-hour service the heat of combustion of all the carbon monoxide (CO) generated during the air blow be utilized in addition to the sensible heat of the gas coming from the generator. This is doubly true when making carburetted water gas from bituminous coking coal. The reasons why this is so are apparent when the following factors are considered."

Nov 1, 1920

By Frank E. Cash

The information in this report covers the accident experience of the pebble-phosphate industry of Florida for 1935 and 1936, as well as the 5 years 1930-34, inclusive, statistics of which were published in Information Circular 69174/. The compilation and publication of such accident experience statistics enable the pebble-phosphate industry, as well as other industries, to consider relative hazards and to compare experience and thereby promote accident prevention.

Jan 1, 1937

By Dipak Sengupta

This study analyzes the safety, technology, and economic impact of eliminating safety fuse from metal/nonmetal mines, based on operation and manufacturer experience over the past five to ten years. If safety fuse is eliminated, blasting accidents will decrease with no technical impact except for some limited, specific applications. The economic impact will be minor for large operations, but will be significant enough for small operations that some small operations will likely close rather than change. The majority of the mines would probably change over, with the extra cost absorbed by the market. Elimination of safety fuse would have obvious impact on the two manufacturers of safety fuse; one manufacturer already produces an alternative system, and will remain unaffected; the other will be affected if they do not change their production strategy. There will be a very minor effect on the mining industry as a whole due to abolishment of safety fuse from the standpoint of employment or production.

Jan 1, 1980

By D. A. Reynolds

A few studies on the relationship of the fusion temperature of the ash on coke to that of the corresponding coal have been made on commercial high-temperature cokes. H. J. Rose3/ in 1921 compared the fusion temperatures of the ashes of 10 coals and the cokes produced from them and concluded that they were in such hose agreement that either figure could be used. More recently, Quarfort4/ found that the ash of coke fused at a somewhat lower temperature than that of the original coal. As the ash of a coal and that off tie coke produced therefrom have the same origin their chemical composition should be identical, provided that carbonization has not altered the inorganic, or ash-forming, constituents of the coal, and such alteration seems highly improbable. However, it has been shown5/ that coke is liable to contamination by iron during crushing and grinding preparatory to sampling. Pieters6/ found that coke ash was contaminated in this manner up to 0.4 percent. Extraneous iron would lower the ash-fusion temperature because such iron may form ferrous silicate, which is readily fusible.7/ These results provide a basis for the prediction that the ash of coke will fuse at a lower temperature than that of the corresponding coal, especially if the fine grinding of the coke was done by rubbing -surfaces of iron, as in a disk pulverizer or bucking plate.

Jan 1, 1940

By John Gross

Studies in grinding efficiencies carried out at the Midvale plant of the U. S. Smelting, Refining & Mining Co. and at the Tooele plant of the International Smelting Co. Were made possible by the cooperation of these two companies with the U. S. Bureau of Mines. Mr. Alan Probert of the U. S. Smelting, Refining & Mining Co. and Mr. E. C. Peterson of the International Smelting Co., devoted their entire time to the work during the respective tests, and their services are hereby gratefully acknowledged. It is a pleasure to acknowledge also the assistance and kindness of the staffs of both companies in making it possible, at considerable trouble and expense, to sample the entire mill circuits and in furnishing the necessary supplies and special apparatus required in the work.

Jan 1, 1929

By Robert E. Green

This Final Report summarizes the results of work accomplished under Contract No. J0215039. It is in an executive overview or executive summary format. The number and description of the various technical reports prepared and submitted is outlined. The essential changes and reasons for the revised program schedule/contract modifications actually enacted in May 1982 are discussed in detail. The evolving mines/deposits list and the accompanying criteria classifications are explained along with the verifications/justifications for adding or deleting specific mines/deposits to the list. Difficulties and problems experienced during the different phases of the project in conjunction with the ensuing remedies are highlighted. The final section of they report is devoted to presenting Davy McKee's suggestions for improvements to future MAS commodity studies. Appendix I is comprised of three of the evolving mines/deposits lists starting with the original RFP list and ending with the final completed list. Appendices II and Ill are tabulated summaries of property data including reserves/resources, assays, production, and operating costs. The figures for the specific mines/deposits are given in "range of values" so as to protect the confidentiality of the individual owners/ operators.

Jan 1, 1983