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To devise an economical, environmentally acceptable method for recycling scrap lead-acid batteries. Approach A combination electrorefining-electrowinning method for recycling lead metal and sludge from scrap batteries was devised which produces a 99.99 + percent pure lead product and eliminates the lead and sulfur oxide emissions that are the normal by-products of high-temperature smelting processes. How the Method Works Lead metal grids and lugs are separated from the battery sludge by washing and screening, and are melted and cast into anodes for electrorefining by the Betts process. The electrolyte used is fluosilicic acid, a large volume waste product generated during the production of phosphate fertilizer. During the electrorefining process, impurities in the anode are trapped and held in an adherent slime blanket on the surface as the anode dissolves while pure metallic lead is deposited on a lead cathode. The major problem in the past has been to recover the lead from the battery sludge which consists of approximately 60 percent lead sulfate, 21 percent lead, and 19 per-cent lead dioxide. In the flow sheet developed by the Bureau

Jan 1, 1983

Prevent the explosion of methane gas or coal dust by replacing air with inert gas inside highwall mine excavations. Approach Use combustion gases as a source of inert gas with low oxygen content to blanket the cutting, head of highwall mining machines. This gas is placed strategically at the collar of the excavation where it enters the hole to replace the mined coal volume. The elimination of oxygen from the hole prevents explosions of gas or dust. How It Works Highwall mining methods arc used when surface mining becomes uneconomical. One method of highwall mining involves use of a horizontal auger to enter the coalbed from a surface mine bench. The coal is mined in a series of horizontal, parallel, and large-diameter holes. Historically, little methane has been associated with auger mining. However, mining technology has extended the reach of auger mining, which can increase the occurrence of methane. Methane explosions at auger mining operations have been increasing. Methane has been the primary fuel source of these ignitions, but coal dust also may have been involved.

Jan 1, 1993

By L. D. Gehi, A. W. Khair, M. Ahmad

"Bit wear presents problems to mining operations because it affects both productivity and economics. Most bit research deals with energy requirements and energy dissipation mechanics for ideal fragmentation during the cutting process.Mechanical cutting leads to dust generation. Past studies involving dust generation due to bit wear concluded that dust concentrations increased considerably after a 7% bit weight loss: leading researchers recommend that the bits be changed at that point.Bit wear is affected by three factors: machine operating parameters in-situ mining conditions and rock properties. Operating parameters such as the depth of cut tool material spray position and the drum's rotating velocity are very important and have a definite impact on bit wear.During the mining process the amount of rock in coal and the strength of that rock is important as abrasion and adhesion take affect. Diffusive wear or deformation becomes dominant only when the temperatures exceed critical. Temperatures rise as a function of drum velocity rock properties and the cutting tool itself.Miner bit surveyIn this study, 15 mines were surveyed, and of those six responded for nine seams. The survey reflected a wide range of information about coal production and bit consumption from continuous miner sections. Also used bits were collected to get first-hand information to analyze wear."

Nov 1, 1995

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Jan 1, 2012

By John J. Mulligan

Lead-silver deposits in the Omilak area, on the western slopes of the Darby Mountains, Seward Peninsula, Alaska, were investigated by the Bureau of Mines, during the 1953 and 1954 field seasons, as a part of the U.S. Department of Interior's continuing program for the development of Alaska's resources. The Omilak area was the scene of early day prospecting and mining activity. The Omilak mine, which operated from 1881 to 1890, was the second producing lode mine in Alaska; the first was a small gold mine near Sitka. Several hundred tons of ore were produced at the Omilak mina; as an indication of grade, 41 tons shipped from Omilak in 1889 contained 75 percent lead and 142 ounces of silver per ton. A prominent, nearby occurrence of lead-silver minerals, found but not explored during this period, has since become known as the Foster prospect. Subsequent exploration of this prospect revealed an abundance of massive galena occurring on an outcrop and as float scattered through limestone talus. Evidence of lead deposition, together with the generally high silver content of lead ores previously shipped from the district, indicated that deposits might be found which would be commercially valuable even in this remote area. To investigate the possibility, the Bureau of Mines made a reconnaissance of the Omilak area and did bulldozer trenching, diamond core drilling, and sampling at the roster prospect. Data resulting from the investigation are presented in detail in this report and are summarized in the following paragraphs.

Jan 1, 1962

By James L. Hendrix

A study was made of the United States Bureau of Mines' chlorine-oxygen leaching process for complex sulfide concentrates. The investigation sought to determine the kinetic order and IT mechanisms involved in the reactions betweens sphalerite, and galena with chlorine. The influence of copper on the extraction rates was also studied. It has been shown the rates of reaction of chlorine in aqueous solutions with sphalerite and galena are both zero order at 373K with the rate limiting step being the chemical reaction. Addition of cupric chloride increased the extractions of both lead and zinc.

Jan 1, 1980

By Michael G. Zabetakis

The process of ?gasfreeing? has been defined3/ as "* * * the removal of oil and vapors from tanks, pipelines, and compartments to render such spaces safe for the intended work," Generally, part or all of a vessel is gasfreed for one of several reasons: Periodic cleaning; tank inspection or repairs; shipyard overhaul or major repairs; or change of cargo, Curing the gas- freeing, flammable or explosive4/ mixtures (mixtures through which a flame can propagate after ignition by an open flame, heated object, electrical charge, or other means) may be produced. These mixtures create an explosion hazard, as the pressures produced after their ignition are often great enough to completely demolish the vessel and kill all those aboard, This paper outlines a study by the Federal Bureau of Mines of the gas explosion hazards likely to be encountered while gasfreeing a vessel compartment. To better understand these hazards it will first be necessary to review the language used in gas- explosions work. This language is considered in the following sections. Inert gases such as carbon dioxide, nitrogen, water vapor, and others can be used to decrease the range of combustible-vapor concentrations in which flammable mixtures are formed. Sufficient quantities of such gases can often be added to cause a mixture that originally was flamable to become nonflammable. Unfortunately, the use of water vapor in this application is complicated by the fact that elevated temperatures are required to keep the water in the vapor state. In practice, it may be difficult to maintain these elevated temperatures throughout the space (such as a cargo tank) to be inerted for any length of time. Accordingly, where other inert gases are not available, it may be desirable to gasfree a Lank by using heated air. To do this, the combustible vapors should be flushed as quickly as possible from the space to be gasfreed. In a properly designed system, large tanks were gasfreed with a littlee as 6 volumes of air per volume of tank capacity.

Jan 1, 1961

By F. M. Carlson

Comparisons are made between the results of the Buckley-Leverett and Kern solutions, which describe immiscible displacement of oil by gas in a linear system and the results obtained from a less restrictive numerical model. This model takes into account the effect of compressibility of the oil and gas and the effect of allowing changes in the amount of gas in solution in the oil. These effects are best exemplified by imposing large pressure drops across the system. With these large pressure drops, comparison of the model solution with the Buckley-Leverett solution reveals that the Buckley-Leverett solution provides estimates of recoveries at breakthrough of the gas that are too low. In contrast to the model, the Kern solution predicts breakthrough recoveries that are too high. A modification to the Kern solution is presented to facilitate more accurate predictions of recovery at gas breakthrough for gas injection at pressures higher than the saturation pressure of the oil.

Jan 1, 1974

By J. D. Hadden

The Bureau of Mines conducted drilling studies in the Pocahontas No. 3, the Pittsburgh, and a western coalbed to establish the gas migration characteristics for each. Gas pressures in the Pittsburgh coalbed were about 260 lb/in2 and in excess of 550 lb/in2 in the Pocahontas No. 3. Caving in drill holes prevented pressure measurements in the western coalbed. The Pittsburgh coalbed contained intersecting "clay veins" which formed gas pressure cells. Although these geological features hamper mining, they can be used to control the flow of methane into a mine working. Methane control techniques are proposed for the Pittsburgh and Pocahontas No. 3 coalbeds.

Jan 1, 1969

By David R. Forshey

This Bureau of Mines report presents a quantitative theoretical analysis of a coupled gasdynamics-heat release system involving the kinetics of water condensation in and behind the rarefaction wave in a shock tube using the method of characteristics. The merger of characteristics to form a shock wave is included.

Jan 1, 1977

By P. J. Dallimore

The Bureau of Mines has calculated general time-dependent solutions for radon diffusion from cylindrical and slab rock samples containing uniform radium distribution. Results have been obtained for several sets of boundary conditions. The method is suitable for determining the effective diffusion coefficient and the effective porosity for radon.

Jan 1, 1983

By L. C. IlsLey

The Bureau of Mines has collected field data and made laboratory investigations of trailing- cable performance in the hope of developing a better and safer cable for use with permissible mining machines . Because of their better insulation and performance , only rubber- sheathed cables were finally considered . The cables tested represented the product of six manufacturers . : After consideration of the results of the preliminary investigations , the conditions under which cables are used in mines , and the better performance of the later types of cables that were submitted as the investigation progressed , the bureau formulated a performance - test requirement and notified the cable manufacturers as follows : The hazards of the trailing cable are such that the bureau has been unable to extend beyond the machine its formal approval to cover the cable as at present developed . However , in the attempt to reduce the hazard as much as possible , cables passing certain tests will be recommended for this service and it is hoped that several cables will be developed to meet this requirement .

Sep 1, 1930

By Jennifer A. Slatnick

The U.S. Bureau of Mines estimated the potential availability of titanium from 39 mines and deposits in 12 market economy countries. The evaluated properties account for 76 pet of the market economy country demonstrated resources, which total 603 Mt of contained titanium dioxide (Ti02) in the minerals rutile, ilmenite, leucoxene, and anatase, and represent 95 pct of current production. Approximately 250 Mt of contained Ti02 could be economically recovered from evaluated titanium operations at January 1992 market prices. In terms of mineral concentrates, this equals approximately 19 Mt of rutile concentrate, 110 Mt of ilmenite concentrate, 47 Mt of synthetic rutile concentrate (in addition to the ilmenite), and 160 Mt of titanium slag that could be recovered. Over the past decade, the titanium minerals industry has adapted to the changing market. In the 1980's, titanium producers expanded production because of the rising demand for titanium products. Today, the titanium industry is in a state of overcapacity, and byproduct revenues, such as that from zircon, have become essential in keeping operations profitable. The industry has also witnessed a greater dependence on upgraded ilmenite products, such as titanium slag and synthetic rutile, because of the expense of rutile and the lower wastes emitted from these upgraded products. As a result of this dependence on upgraded ilmenite products, South Africa has become a leading titanium producing country and has displaced Australian production.

Jan 1, 1994

By B. W. Gandrud

[The meaning of the term "bauxite' has always been somewhat vague and indefinite, and the term has been used in various applications to denote sometimes a rock, sometimes a mineral, but more frequently an ore. It seems logical to think of bauxite as an ore, however, because a very large part (probably at least 85 per cent) of the entire world's production of bauxite is at present being used as a source of aluminum and aluminum chemicals. In the United States there are two districts that, produce bauxite - the Arkansas district and the Alabama-Georgia-Tennessee-Mississippi district. The deposits in Mississippi have been discovered recently and are riot as yet productive but it seems reasonable to consider them as apart of the-district hat includes the deposits of Alabama, Georgia, and Tennessee. The, two districts are often referred to as the Arkansas field and the Appalachian field. Of these two the Arkansas field has been by far the largest producer, and at present over 90 per cent of the bauxite production of they United States comes from the Arkansas field. The bauxite industry in the Appalachian field had its beginning in 1889, and since that time the total production of the states of Alabama, Georgia, and Tennessee has been, nearly a million tons. The production of bauxite in this field has languished in the last five, or six, years, and In 1927 its production was only about 14,000 tons, according to Harder4. The recent decrease in production is due mainly to the fact that many .of the known deposits of commercial-grade ore have become exhausted. There are, however, considerable quantities of low-grade bauxite in the Appalachian field, but these have not been available because there has been no satisfactory way of concentrating low-grade bauxite. The quantity, of low-grade material in the Appalachian field is probably, fully as large as the tonnage of commercial ore which the field has already produced.]

Jan 1, 1928

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

SUMMARY AND CONCLUSIONS This report describes a study to develop a detailed set of guide¬lines and equipment recommendations to be used as a guide for mine operators, mine inspectors, and equipment manufacturers in implementing the emergency escapeway standards for metal and nonmetal underground mines. It was sponsored by the United States Bureau of Mines. The first part of this report reviews the historical background of metal and nonmetal mine fires and the development of present and proposed mandatory standards. This is followed by a discussion of the survey of representative mines and how the proposed standard effects these mines. The remainder of the report covers technical discussions of each escapeway component including a comprehensive computer sim¬ulation of mine evacuation. Following the technical discussion of each group of escapeway components is a list of the pertinent guidelines. A study of past mine fires indicates that a serious commitment by operators to the proposed escape standards would be instrumental in saving lives in the future. The most significant event in a recent mine fire, in which no deaths resulted, was the very early discovery of the fire. The evacuation was orderly thanks to careful preparation by the mine personnel. However, the mine was possibly only spared a real disaster because of the discovery of the fire almost at its inception. Installation of automatic fire and smoke warning devices may be the single most important step in preventing future disasters. The self-rescuer has saved many lives in mine fires. Men have also died while attempting to use them. The reason men died was either because the unit was not working or the miner did not understand how or when to use it. There is no good excuse for either of these conditions occurring. Regular maintenance and inspection should prevent unit failures. Frequent instruction on when and how to use the self¬rescuer would prevent confusion and potential fatalities. A means of

Jan 1, 1976

Improve surface mine haul-age truck safety and efficiency by providing a means for sensing the weight and distribution of the truck's load. Approach The safety hazards and the economic implications of overloading mine-haulage trucks were analyzed to determine the net effect of that practice on mine operations. The analysis indicated that: Ten to 25 pct overloading is typical; Higher haulage, tire, and maintenance costs occur due to overloading (a 20 pct overload was estimated to increase operating costs 7 pct per ton); Ten to 15 pct of haulage? truck injuries and fatalities are attributable to overload conditions, at a cost over one million dollars per year to the mining industry. Vehicle-weighing technology that conformed to the performance specification for an off-highway haulage truck overload detection system was selected for in-mine testing. How It Works Normally, volumetric estimates are made during the loading sequence which do not account for the varying ore density. Hence, the actual weight of a load is never precisely known. By providing a precise measurement, an overload detection system will not only indicate vehicle overloading, but will also show under-utilization of the truck. One system tested by the Bureau of Mines was the ?Load Analyzer" manufactured by Pactronics Corporation in California. This system consists of a meter-type analog readout for the cab console and three "Electrosensors" (linear variable differential transformers) attached to the main frame. Using conventional welding and brazing techniques, two sensors are attached between the front members of the engine sub-frame and the top of the left and right trailing arms (one sensor per arm). The same techniques are used to attach the third sensor to the rear centerline of the truck. between the main frame cross member and the A-frame. The readout unit on the cab console indicates by color-coding whether each sensor loading is under (green), at (yellow), or over (red) the pre-set rated load. The three-sensor configuration with in-dependent readouts also detects uneven distribution of the load.

Jan 1, 1984

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 Joseph Cervik, Maurice Deul, Albert Sainato

This Bureau of Mines report deals with water infusion of coalbeds, which can control methane emission at face areas during developmental mining and which may sometimes suppress dust. Studies show that water infused into the coalbed flows through the fracture system and displaces the methane in the fractures and prevents migration from the solid coal. Displaced gas migrates away from the face area that has been water infused and enters the return ventilation airways. A gradual decrease in methane emission is observed from the start of infusion until the infused zone is mined through. Depending on the permeability of the coalbed, infusion pressures ranged from 300 to 2,200 lb/in2. Face emissions in the Upper Kittanning coalbed were reduced by 89 pct; reductions of 38 to 79 pct were measured in the Pittsburgh coalbed depending on the relationship between the face cleat direction and mining direction. Respirable dust levels were reduced by about 75 pct on a longwall section in the Pocahontas No. 3 coalbed and by about 50 pct on a development section in the Upper Kittanning coalbed, but no statistically reliable reduction was found in the respirable dust levels in the Pittsburgh coalbed.

Jan 1, 1977

By Edward D. Thimons

The Bureau of Mines conducted in-mine tests to determine correction factors applicable to low-velocity airflows (below 150 fpm) measured by the smoke cloud, vane anemometer, and oil of wintergreen tracer gas techniques 0 The average correction factors found for these methods of measurement were lower than those reported in the literature for use with higher velocity measurements. All tests measured airflows with controlled average velocities ranging from 50 to 100 fpm. Correction factors averaged about 0.75 for readings taken by the centerline smoke cloud method, remotely controlled and stickheld center" line anemometer, and split traverse stick-held anemometer. For hand-held centerline anemometer and oil of wintergreen tracer gas readings, correction factors averaged about 0.67. Since special anemometers are needed to measure airflows in this low-velocity range, and since proper calibration of these anemometers is difficult and expensive, the use of anemometers for low-velocity measurement is imprac-tical. On the other hand, smoke and oil of wintergreen give results as con-sistent as those obtained with specially calibrated, low-velocity anemometers. Furthermore, they are easy to use and inexpensive.

Jan 1, 1979

By G. B. Shea

The accident experience of the California petroleum industry for 1927 was characterized by a decrease it .the number of fatalities. The year closed with a total of 41 fatal accidents, as compared with a total of 54 for the preceding year. 3 In percentage, the figure for 1927 represents a decrease of 24 per cent from that of 1926 and evidences the promising results of organized safety work, in which the industry in California has taken an absorbing interest. The percentage of decrease for 1927 is the largest recorded in any one year since the compilation of the fatality record in the California petroleum industry was begun. Although good progress has been made during the past few years, much remains to be done to reduce still further the human and economic waste caused by accidents. This review is intended to show the employee, as well as the employer, the proximate and contributing cause of accidents. To increase the value of the report, preventive measures in various instances are suggested, on the theory that accidents of a similar nature will occur unless remedial action in taken to remove the cause.

Jan 1, 1928