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By T. H. Jeffers

Significant amounts of cobalt, a strategic and critical metal, are present in readily accessible spent copper leach solutions. For example, recovery of cobalt at two major u.S. copper operations could produce about 1,300,000 lb Co annually, about 13 pct of domestic consumption. However, techniques such as solvent extraction and precipitation have not proven cost effective in separating and recovering the cobalt from these low-grade domestic sources. The Bureau of Mines has devised a procedure using a chelating ion-exchange resin to extract cobalt from a pH 3.0 copper leach solution containing 30 mg/L Co. Cyclic tests in 4-ft-high by 1-in-diam columns gave an average cobalt extraction of 95 pct when 65 bed volumes of solu-tion were processed at a flow rate of 4 gpm/ft2 of resin area. After an impurity scrub, eluates contained, in grams per liter, 0.4 Co, 0.2 Ni, <0.001 Cu, 1.3 Fe, 2.8 Zn, and 0.008 AI. Solvent extraction procedures to remove impurities, reject nickel, and concentrate cobalt produced a cobalt sulfate solution containing 80 g/L Co, 0.05 g/L Ni, and not more than 1 mg/L Cu, Fe, Zn, or AI. Based on data from commercial electro-winning operations, this solution appears suitable for production of metallic cobalt.

Jan 1, 1985

This report was limited to a search of available literature on under- ground methods to combat acid water pollution. From this review it is evident that very little work has been done in this specific area. It is also evident that there are specific areas of mining engineering and mining related hydrology and geology that need further research efforts to solve the many water problems. They are: (A) Composition, variation and availability for oxidation of sulfur in strata. (B) Rate of oxidation of sulfuritic materials. (C) In situ limestone and its influence on underground acid drainage. (D) Structural, stratigraphic and hydrologic character of old mining areas as a basis to make decisions about adjacent new mining areas. (E) Operational changes in mining methods to prevent pollution. (F) Sealants for underground coating to exclude water from contact with pyrite to inhibit formation of the contaminants. Such a program has been initiated on refuse piles. The prime purpose of this report is to investigate those practices which have been used to regulate or control water accumulation and prevent harmful mine drainage. A supplemental purpose is to indicate those areas which need further research to prevent underground mine water pollution.

Jan 1, 1970

By John D. Corrick

Three species of chemosynthetic iron- and sulfur-oxidizing autotrophic bacteria have been isolated from the leaching waters of copper mining areas. These species are: The sulfur-oxidizing Thiobacillus concretivorus, the iron-oxidizing Ferrobacillus ferrooxidans, and a sulfur- and iron-oxidizing bacterium closely resembling Thiobacillus ferrooxidans, INTRODUCTION Among several suggested new processes for treating marginal ores in the United States, none is more intriguing than the possibility of extracting metals from low-grade materials by the action of microorganisms One phase of a Federal Bureau of Mines investigation toward developing such a procedure was to isolate and identify specific chemosynthetic iron and sulfur. oxidizing autotrophic bacteria native to certain domestic copper deposits where leaching is practiced. The bacteria or microorganisms considered important to this investigation are those capable of producing solutions of ferric sulfate and sulfuric acid. Solutions of this type are excellent solvents for some copper minerals By establishing the presence of these bacteria at certain copper-leaching areas, strength would be given to a theory that microbial activity is partly responsible for the oxidation that takes place at these areas. Their presence also advances possibilities for controlled use of microbial action in metal extraction processes. Leathen4/ has demonstrated that one of the chemosynthetic iron-oxidizing bacteria, Ferrobacillus ferrooxidans, can oxidize 200 parts per million of ferrous iron to the ferric state in 3 days,

Jan 1, 1961

By G. W. Elger

The Bureau of Mines conducted laboratory and larger scale studies on samples of domestic perovskite and ilmenite ore concentrates to devise a procedure for recovering TiC from these ores. From the concentrates, mixtures of titanium and calcium carbides were produced. The carbides were then ground and reacted with water. This reaction decomposed the CaC2 to acetylene and hydrated lime and simultaneously liberated the TiC. Using a combination of elutriation and gravity-separation techniques to separate the hydrated lime, approximately 93 pct of the titanium was subsequently recovered as purified carbide containing 54 to 70 pct titanium with CaO content as low as 0,6 pct. This combination of techniques can be used to separate more than 90 pct of the CaO from the TiC. Therefore, this carbiding procedure is a viable method for treating titaniferous materials, including perovskite, that contain more than 20 pct CaO. Tests made in a static-bed reactor showed that for the reaction of TiC with elemental chlorine to produce titanium tetrachloride (TiCI4), a temperature of at least 940° F is desirable to achieve a suitable extraction of titanium in a laboratory chlorination reactor. In fluidized-bed tests at 840° F, 98 pct of the titanium contained in TiC was extracted.

Jan 1, 1980

By F. E. Brantley, D. M. Yergensen, D. A. Martin

Fluidized - bed roasting was investigated as a means of decomposing gypsum and gypsum mixtures to produce a gas rich in sulfur dioxide and a lime or portland cement residue . Ninety- eight percent desulfurization of gypsum in a 10 - inch fluidized- bed reactor took 1.5 hours at an operating temperature between 1,200 ° and 1,225 ° C. A cement- type residue was obtained but had to be refired at 1,450 ° C before mortar prepared from it met the physical specifications for cement .

Jan 1, 1963

By D. K. Deardorff, Laurance L. Oden, H. Kato, M. I. Copeland

The equilibrium relationship of hafnium and tantalum was studied to facilitate alloy and property investigations . The data obtained are presented graphically as the equilibrium diagram . Alloys were prepared from high - purity components by nonconsumabletungsten- electrode arc melting . Data for the equilibrium diagram were obtained by optical pyrometry , metallography , X- ray diffraction of heat treated specimens , X- ray diffraction using a high- temperature camera , and differential thermal analysis . During the investigations , a casting apparatus was constructed , and the existing melting - point apparatus was improved . The bcc allotrope of hafnium forms a continuous series of solid solutions , called beta , with tantalum which exhibit a minimum melting point at 20 wt pct tantalum and 2,110 ° C. At 24 wt pct tantalum and 1,050 ° C , hafnium- rich beta decomposes in a monotectoid reaction to yield alpha and tantalum- rich beta . The monotectoid isotherm extends from 5.5 to 60 wt pct tantalum . The twophase region , in which hafnium- rich and tantalum- rich beta solid solutions are immiscible , rises to a maximum temperature of 1,265 ° C at 38 wt pct tantalum . The solubility of hafnium in tantalum decreases from 40 wt pct at the monotectoid temperature to 20 wt pct at 750 ° C.

Jan 1, 1964

By Maria I. De Rosa

For all coal mining categories, data on coal mine fires during 1990-1999 have been reported as actual numbers and calculated values. 1. For each mining category, actual numbers include the total number of fires, fire injuries, employees&apos; working hours, lost workdays, and coal production (for underground and surface mines only) for a 1 0-year period (1 990- 1999) and for five successive 2-year periods with the 10-year period. These numbers have also been reported by state ( 10-year period). The actual number of fire fatalities has been reported by time period. Furthermore, actual numbers of fires for the five 2-year periods have been reported by ignition source, method of detection and suppression, equipment involved, location, and burning material. Actual numbers of fire injuries per number of fires causing injuries and total fires have been reported by year, ignition source, equipment involved, and location. 2. For each mining category, the calculated values include the fire and injury risk rates during the 10-year period and the five 2-year periods. The fire risk rate (Frr) values were calculated according to the USBM formula [Pornroy and Carigiet 19951. The injury risk rate (Irr) values were calculated according to the MSHA formula [MSHA 1991a, 1992, 1993, 1994a, 1995a, 1996, 1997, 1998b, 1999c, 20001. Also, risk rate values for individual states (10-year period) were calculated according to the above-mentioned formulas. Of note is that only the risk rate values for the 10-year and five 2-year periods and risk rate values for individual states with the highest number of fires and fue injuries were considered for comparison purposes. The fatality risk rate values were not calculated because of the extremely small number of fire fatalities during the 1 0-year period. 3. Calculations of risk rate values are as follows: a. Fire risk rate (Frr) value: Number of fires per million tons of coal produced [Pornroy and Carigiet 19951. b. Injury risk rate (Irr) value: Number of fire injuries multiplied by 200,000 working hours per total employees&apos; working hours [MSHA 1991a, l992,1993,1994a, 1995a, 1996, 1997, 1998b, 1999c, 20001. The Irr value is the average risk rate value for the number of fire injuries per 200,000 working hours for a given time period.

Jan 1, 2004

By E. D. Gardener, Byron O. Pichard

"Methane, frequently called fire damp or marsh gas, is very well known to coal miners but to thy average gold miner it means nothing, as it is not associated generally with the rock formations in which gold is found.We have recently been conducting a study of mine air in typical gold mines on the Pacific Coast, and out of five California mines in which the air was sampled, three showed methane. Each of these three mines, referred to below as mines A, B, and C, have had accumulations great enough to be ignited. An authentic report from another California, gold mine, which has not yet been sampled, states that recently the superintendent was seriously burned by the ignition of a pocket of gas. This mine is later mentioned as mine D.Mine A is an old mine which had been abandoned for several years and permitted to fill with water. It has been unwaterad recently, and is now being developed at greater depths. During the unwatering, gas bubbles formed on the water and upon being ignited burned freely. It is reported that two men were seriously burned from accidentally igniting the gas. Samples of the bubbles on analysis showed high percentages of methane. Since the mine has been unwatered, no trouble has been experienced through gas being ignited. However, out of a total of six air samples which we took recently in scattered working places, all showed small amounts of methane, the methane content being 0.06, 0.04, 0.05, 0.04, 0.04 and 0.07 per cent, respectively. When these samples were taken methane was not suspected, but its general presence in the mine air indicates that it is being given off constantly."

Dec 1, 1921

By E. D. Gardner

The Bureau of nines, in cooperation with the mining companies of the Southwest, is conducting an investigating to ascertain the safest and most economical explosives to use in metal mines, and to ascertain the best methods of blasting under various conditions. A part of this investigation has been a study of drilling and blasting drift rounds in metal mines. This paper covers one phase of work on drift rounds and discusses the methods of loading the individual holes of the rounds. The blasting tests, on which this paper is based, were made at the Copper queen Branch of the Phelps Dodge Corporation at Bisbee, Arizona.

Jan 1, 1927

By Henry J. Kellner, Michael J. Brnich

This U.S. Bureau of Mines report addresses issues involved in using a limited number of training apparatus to give hands-on self-contained self-rescuer (SCSR) training to a succession of miners, and provides guidance regarding methods for minimizing the spread of infectious diseases. Procedures used for preventing the spread of infectious organisms in dentistry, cardiopulmonary resuscitation (CPR) training, and scuba training are examined. The sanitizing methods of three organizations that require individuals to insert the mouthpiece as part of the SCSR donning sequence are discussed. It was found that each of these organizations was able to render their mouthpiece assemblies microbe free simply and inexpensively.

Jan 1, 1989

By L. C. IlsLey

The service given by a flame safety lame is twofold: It provides a safe light and it gives evidence of the condition of the mine atmosphere relative to the presence of methane and the deficiency of oxygen. Since the development of portable electric mine lamps, flame safety lamps are little used for lighting,but their use as detectors is as extensive and important as ever. A flame safety lamp in the hands of a trained user will definitely how methane concentrations as low as 1 percent, which in well below the lower explosive limit of methane and air. However, this does not always suffice, especially when making studies of mine ventilation, where it may be desireable to detect concentrations below 1/2 of 1 percent.

Jan 1, 1936

By L. C. IlsLey

[The service given by a flame safety lame is twofold: It provides a safe light and it gives evidence of the condition of the mine atmosphere relative to the presence of methane and the deficiency of oxygen. Since the development of portable electric mine lamps, flame safety lamps are little used for lighting but their use as detectors is as extensive and important as ever. A flame safety lamp in the hands of a trained user will definitely show methane concentrations as low as 1 percent, which in well below the lower explosive limit of methane and air. However, this does not always suffice, especially when making studies of mine ventilation, where it may be desireable to detect concentrations below 1/2 of 1 percent.]

Jan 1, 1936

Great strides have been made in recent years to reduce the disaster potential of underground mine fires. However, mines can still be caught unprepared for a fire emergency. Fires can grow too large before they are detected, warning systems can be too slow and uncertain to reliably signal the danger, and suppression systems can be inadequate to extinguish the flames. New mining systems and equipment may create unanticipated fire hazards, and new materials may generate highly toxic combustion products. This report contains papers that summarize recent significant developments from the Bureau of Mines mine fire protection research program relating to these problems. Certain of these findings are also applicable to surface mining operations. The papers fall into the general categories of fire detection and instrumentation, fire warning, fire suppression, diesel equipment, spontaneous combustion, and toxicity analysis of combustion products.

Jan 1, 1988

By W. M. Myers

The U. S. Bureau of Mines conducted an investigation to determine the cause of the deterioration of Portland cement during storage and transportation , and to discover a means of preventing it . All available printed sources of information on this subject have been examined and a bibliography has been compiled . The subject has also been discussed with the leaders in the cement industry ; the present report is the result of their cooperation , and is based principally on information thus obtained . Deterioration of Portland cement during storage over any considerable period of time has long been noted ; closely related to it is deterioration of cement during transportation, which involves not only the time factor of storage but also exposure to varied climatic conditions . Deterioration in both cases is due to hydration of the cement by absorption of moisture from a humid atmosphere , or by exposure to actual rain-fall . After hydration cement possesses no cohesive power ; the degree of deterioration is directly proportional to the degree of hydration . The amount of deterioration of Portland cement during storage has been accurately determined in an investigation by the Structural Materials Research Laboratory , in cooperation with the Portland Cement Association . Cement stored in a shed in cloth sacks retained 80 per cent of its original strength after three months storage ; 71 per cent after six months ; 61 per cent after one year ; and 40 per cent after two years . The deterioration of Portland cement during storage and transportation was noted particularly in France during the World War . Information concerning cement used by the American Expeditionary Forces was furnished by Lt. Col. H. S. Spackman and Major E. C. Eckel , U. S. R. , who had charge of practically all matters concerning cement used by the A. E. F. The cement used by the A. E. F. came from the following sources : 42,000 tons was French , Swiss , and Spanish cements ; 120,000 tons was English cement ; 55,000 tons made in plants operated by the A.E.F .; 500 tons ( Not over) from America . Deterioration was most marked in cement from the first source .

Jun 1, 1922

By Thomas M. Garland

Reports that set forth the pertinent facts of existing secondary-recovery operations are an integral part of the work of the Bureau of Mines in promoting conservation and efficient utilization of the petroleum resources of the Nation. Knowledge of the success or failure of waterflood projects in an area is very useful to other operators. Although projects will not have identical results, information concerning the flood performance, method of operation, and difficulties encountered on one project will help operators to determine the feasibility of flooding a similar sand and to select the methods of operation most likely to prove successful. The increasing cost of discovering and developing new oil reserves, as well as the unending effort to reduce operating costs and increase ultimate oil recovery from known petroleum reservoirs, has required the petroleum industry to evaluate continuously the performances of various secondary-recovery methods. Waterflooding was recognized early by the petroleum industry as a possible means of increasing oil recovery. From the early accidental floods in Pennsylvania and through many haphazard attempts to inject eater into oil-bearing formations, waterflooding emerged as one of the more important methods of oil recovery. Waterflooding is important not only to the oil industry but also to the economy of the area concerned.

Jan 1, 1962

By Anthony W. Sparks

The Bureau of Mines conducted tests designed to compare its breathing metabolic simulator (BMS) with other methods that are currently used to evaluate the performance of respiratory protective equipment. The BMS is a commercially developed device that uses a piston cylinder to simulate breath movement. Using a propane furnace that consumes oxygen and forms CO2, the BMS also simulates the respiratory metabolism of humans. The breathing and metabolic subsystems of the BMS are described in detail in this report. Results are compared from tests that used the BMS to evaluate respiratory equipment and from tests that used human subjects for the same purpose. The BMS was also tested against a pulsatile breathing machine (PBM) previously designed by the Bureau. Both machines were used to test respiratory equipment, and the test results are compared in this report. To illustrate typical applications of the BMS, the report briefly describes how the BMS was used to test two different types of closed-circuit respiratory apparatus, and the test results are presented. This research showed that BMS test results compared more closely to the results of tests that used human subjects than did results obtained using the PBM.

Jan 1, 1980

By C. P. Mangelsdorf

When the finely bedded shale frequently encountered over coal seams experiences a separation, the material below the separation must behave like a beam or plate in that it must resist both bending and shear. Be-cause of the weakness in interlaminar shear inherent in such strata, shear deflections that are usually ignored in isotropic beam theory may account for a significant part of the total roof sag. Similarly, when a roof truss is installed in such a roof the upward displacement reducing the sag will have components due to shear as well as bending. Questions asked by mine operators about the installation of roof trusses frequently deal with optimum position, slope, and initial tension of the inclined chords. This Bureau of Mines report examines the effects of those chord parameters on the strain energy of both shear and bending and offers optimum values that will minimize the total strain energy of the immediate roof. Design charts are provided, several design examples are included, and the results are compared with current practice. The effects of in situ stresses are investigated and are shown to be equivalent to an additional load on the beam.

Jan 1, 1988

By Maria I. De Rosa

Coal mine fires pose a constant danger to the safety of miners and to their livelihood. Underground mine fires pose an added hazard because of the confined environment with remote exits. Enactment of safety regulations [30 CFR2 75 and 771 for under- ground coal mines and surface coal operations has greatly improved the safety of miners. However, mine fires and fire injuries remain serious hazards for all coal mining operations. This report analyzes mine fires and fire injuries for all U.S. coal mining categories (underground coal mines, surface of underground coal mines, surface coal mines, and coal preparation plants) during 1990-1999. Fires involving contractors are also included in the analysis. Similar analyses (for underground coal mines only) by the former U.S. Bureau of Mines (USBM) were reported by McDonald and Pornroy [I9801 and Pornroy and Carigiet [I9951 for 1950-1977 and 1978-1992, respectively. For comparison purposes, data for 1978-1 992 are mentioned in the "Underground Coal Mine Fires" section of this report. Detailed analyses of mobile equipment fires for all underground and surface coal and metal/nonmetal mining categories during 1990-1999 have recently been reported by NIOSH [De Rosa 20041. Risk rate values (fire and injury risk rates) for the 10-year period (1990-1999) and for five successive 2-year periods within the 10-year period are derived. Risk rate values for individual states for the 10-year period are also derived. Other variables by state and time period include employees&apos; working hours, lost workdays, and coal production (underground and surface coal mines only). The number of fire fatalities is reported by time period. Variables such as ignition source, method of detection and suppression, equipment involved, location, and burning material are reported by five 2-year periods only. Furthermore, the number of fire injuries per number of fires causing injuries and total fires has been analyzed by year, ignition source, equipment involved, and location. For comparison purposes, the major fire and fire injury findings for all coal mining categories have been reported. The data in this report were derived from "Injury Experience in Coal Mining" [MSHA 1991a, 1992,1993,1994a, 1995a, 1996, 1997, 1998b, 1999c, 20001, "Fire Accident Reports" [MSHA 199 1 b,c; 1994b; 1995b,c; 1998a,c,d,e,f; 1999a,b,d,e], MSHA "Fire Accident Abstracts" internal publications, and verbal communications with mine personnel. Mining companies are required by 30 CFR 50 to report to MSHA all fires that result in injuries and fires that are not extinguished within 30 min of discovery. A small number of fires lasting <30 min without injuries reported in the "Fire Accident Abstracts" have been included in this report. The analysis in this report will provide the National Institute for Occupational Safety and Health (NIOSH), the Mine Safety and Health Administration (MSHA), and the mining industry with a better understanding of the causes and hazards of mine fires and fire injuries. It will also form a basis for developing future fire research programs.

Jan 1, 2004

By Paul Hopkins

The following methods have been selected from a large number tried while assaying several hundred samples of placer concentrates. It is thought that some of these methods may be useful to those who are required to assay similar products containing large quantities of metallic articles, such as jeweler&apos;s sweepings. No great difficulties will be encountered in assaying black sand from beaches or river bars. Such samples require care in grinding and sifting so that no oversize particles of sold or platinum are lost. It is also necessary to have sufficient silica in the flux to form a fluid slag with the excess of iron, magnesium, or chromium Which such samples contain.

Jan 1, 1934

By Paul Hopkins

The following methods have been selected from a large number tried while assaying several hundred samples of placer concentrates. It is thought that some of these methods may be useful to those who are required to assay similar products containing large quantities of metallic articles, such as jeweler&apos;s sweepings. No great difficulties will be encountered in assaying black sand from beaches or river bars. Such samples require care in grinding and sifting so that no oversize particles of gold or platinum are lost. It is also necessary to have sufficient silica in the flux to form a fluid slag with the excess of iron, magnesium, or chromium which such samples contain. It is much more difficult to assay black sands, or concentrates, produced in large-scale placer-mining operations. These products are usually much harder and more abrasive than the beach black sands. They also contain numerous metallic particles resulting mainly from wear on the mining machinery. These particles consist chiefly of iron or steel but also contain lead, copper, and alloys such as babbitt, solder, brass, ferrosilicon, etc. Fairly large particles of gold are often found. Some samples will contain as much as 10 percent of such metallic particles. It is not feasible to remove the particles of iron with a magnet and discard them, as they invariably contain gold, sometimes a considerable amount. This gold is attached to the iron particles by rust or wedged into cavities. Scraps of sheet iron are often found which have become tightly folded or rolled and contain gold or amalgam within the folds.

Jan 1, 1934