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By Richard E. Dawes

Physical variables, a principal factor in the economies of mineral production, affect both capital and direct operating costs. By using a revenue-cost system for the framework, the analyses of revenue and cost categories demonstrate the relative importance of groups of physical variables, whether explicitly defined or not, to a lead-zinc mining operation. Physical variables affecting the producer represent about 60 percent of the total system influence as expressed by cost ranking. Other physical variables affect the remaining costs as controlled by the smelter, the transporter, and the landowner. Such resource conservation aspects as mineral losses due to mining method and mineral processing constitute a portion of the total revenue effects of physical variables. The physical variable revenue-cost system presented in this report offers a framework for cost-benefit analysis of mineral related research.

Jan 1, 1969

By J. Roger Loebenstein

Demand for arsenic exceeded supply, and major domestic and foreign producers allocated available supplies to customers for the fourth consecutive year. Major demand for arsenic was about evenly divided between industrial chemicals and agricultural chemicals. Legislation and Government Programs.-Effective April 1, 1981, taxes were collected from companies producing and importing 42 chemicals and petroleum products designated as hazardous, The revenue was used to begin funding of the 5-year, $1.6 billion "superfund" being established under Public Law 96-510, the Comprehensive Environmental Response, Compensation, and Liability Act, designed to help clean up spills of hazardous substances throughout the United States. As hazardous chemicals, arsenic metal and arsenic trioxide were taxed at the rate of $4.45 and $3.41 per short ton, respectively.

Jan 1, 1982

By Thomas P. Mucho, Dennis Dolinar, Christopher Mark

During the 1990s, the former U.S. Bureau of Mines conducted a number of field studies in which the performance of different types of roof bolts were evaluated in different geologic environments. The studies used a standard suite of measurements, including multipoint extensometers, strain-gauged roof bolts, and roof bolt load cells. The sites were chosen to investigate the effect of a variety of parameters, including installed tension, bolt capacity, grout annulus, and horizontal stress orientation. Although not fully successful, the measurements provided valuable insights into each of these issues. They also showed that instrumentation and monitoring have important advantages over observational methods for comparing the performance of different roof bolting systems.

Jan 10, 2000

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

INPUT FORMAT INSTRUCTION FILE FOR PROGRAM MFIRE GENERAL RULES FOR DATA INPUT: $THERE IS NO NEED TO DISTINGUISH INTERGER AND REAL NUMBERS. $ $ SYMBOLS FOR NUMERICAL INPUT INCLUDE THE FOLLOWING $ $ 1234567890 -+BLANK $ $ * FREE FORMAT IS ALLOWED. COMMA AND BLANK SPACE CAN BOTH BE $ $ DELIMITERS. SEQUENTIALLY DISTRIBUTED BLANK SPACES ACT AS ONE $ $ DELIMITER. BLANKS ADJACENT TO A COMMA HAVE NO DELIMITING EFFECT $ $ * A ZERO INPUT CAN BE OMITTED BUT NOT THE DELIMITERS EXCEPT WHEN $ $ THE ZERO INPUTS ARE THE LAST ONES ON A LINE. $ $ * A LINE WHOSE FIRST NON-BLANK SYMBOL IS "$ IS AN INSTRUCTION $ $ LINE WHICH WILL BE IGNORED IN A PROGRAM RUN. $ $ * A LINE WHOSE FIRST NON-BLANK SYMBOL IS NEITHER ONE USED IN THE $ $ ABOVE LIST FOR NUMERICAL INPUT NOR "$, OR WHICH CONTAINS MORE $ $ THAN 3 SYMBOLS OUTSIDE OF THE LIST, IS A COMMENT LINE WHICH WILL $ $ BE SHOWN IN THE OUTPUT FILE. $

Jan 1, 1990

By John J. McClelland, Gerald T. Homce, John R. Thalimer

The U.S. Bureau of Mines has investigated the early detection of insulation failure in squirrel cage induction motors for the past 4 years. Research was done using a sophisticated empirical data-modeling technique based on values calculated from a motor's voltage and current phasors. This technique produces two polynomial equations that calculate the insulation leakage current and power. These models were implemented in a prototype system that monitors six motors on a continuous miner for insulation leakage. These insulation leakage values are used to anticipate insulation failure. The system consists of a motor-data-system for each motor on the machine and a control computer located away from the miner. Each motor-data-system consists of an analog interface to the motor's voltages and currents, a single-board computer that reads digitized data and calculates voltage and current phasors, and a bus node that interfaces the single-board computer with the rest of the system by way of a serial bus system. Using this bus system, the control computer requests and receives phasor data from the motor-data-systems. From these data the control computer calculates and displays two deterioration values for each motor, for leakage current and power, using Bureau-developed models. These values are stored in a data base from which the user can display graphs of each motor's deterioration values over time.

Jan 1, 1992

Coal miners, especially roof bolter and continuous miner operators, work in a hazardous underground environment where they are often exposed to poor roof conditions. Nearly 500 rock fall injuries are reported each year, and 99% of them are caused by rocks falling from between the roof bolts. These loose rocks that injure miners are usually just a few inches thick, but on average weigh 280 pounds. NIOSH has found that most rock fall injuries can be prevented by installing roof screen during the bolting cycle. Roof screen is a sheet made of steel wires in a grid pattern. When screen is bolted up against the mine roof, it provides far more coverage than any common surface control used in the mines today. Because more mine roof is covered, there is less chance that a rock will fall and injure a miner. The facts about roof screen are shown in the new NIOSH video entitled “Make It Safer With Roof Screen.” Using extensive underground footage, the 7-minute video shows how well screen keeps loose rock from falling in difficult roof conditions. Techniques for installing screen from both outside-controlled and walk-thru roof bolting machines are shown. The video also provides safe handling tips, best practices, and information about machine technology that can greatly improve material handling. Throughout the video, a coal mine safety manager and a shift foreman talk about the tremendous difference that roof screen has made at their mines. An instructional booklet supplements the video with additional information. It presents compelling data from mines that have practically eliminated rock fall injuries with a roof screening program. Other sections of the booklet discuss in greater detail roof screen installation, tips for manual screen handling, a material handling system for roof screen, and use of the personal bolter screen, which can be easily handled by one person. Screen specification and custom ordering are described, including the sizes of screen, grid sizes, reinforcing (indicator) wires, edge cut options, and screen strength. A list of additional sources of information is also provided. Nearly every mine eventually encounters poor roof. Screen is one of the most powerful control techniques available. This new video will help make mine managers aware of screen, and it can help them in developing a roof screen installation program. It also serves as an information source and teaching tool for safety managers and trainers. The video can easily be integrated into new miner training programs or annual refresher training.

Mar 1, 2005

By Fred N. Kissell

The new MSHA diesel rules have stone mine operators looking hard at pos¬sible upgrades to their ventilation systems. There are existing methods to reduce diesel engine emissions (MSHA, 2001)(Head, 2001b),but many operators will decide that a ventilation upgrade is necessary is well. NIOSH hay several stone mine ventilation projects underway, but in the meantime a good information resource is the work done by the U.S. Bureau of Mines in the 70's and 80's on ventilation for oil shale mines. The Bureau conducted this research because oil shale mines were projected to be gassy and would, therefore, require a lot of ventilation air. The focus of this oil shale work was on the use of jet tans for lace area ventilation, and on stoppings that would he low Lost and leak-tight. The work also considered changes in mine design to reduce the number and size of stoppings. The findings are still applica¬ble to stone mines.

Jan 1, 2002

Improve the dust-control effectiveness of the Rotoclone1 dry-dust collection systems used on surface coal mine drills.

Jan 1, 1994

By G. T. Brow

An experimental method is described for testing diffusion of gases in crude oils at pressures and temperatures up to 3,000 psia and 200° F. A sampling technique was developed to withdraw by constant-pressure mercury displacement about 60 µl of oil from the diffusion cell through any of several 1/2-in vertically spaced capillary tubes and to trap about 4 µl of the oil in a specially designed microsampler. Oil trapped in the microsampler can be completely inserted in the sample inlet of a chromatograph. From analysis in a three-stage chromatograph (GLC), gas concentration in a sample is determined from the ratio of gas peak heights to area of peaks of reference components (hexanes or heptanes) in the oil. A diffusion coefficient is calculated from measured concentration profiles with known equations for diffusion in finite or semi-infinite systems, depending on whether the gas has or has not reached the end of the oil column. Results are given for a test of methane diffusing at 2,560 psia and 160° F in crude oil from the Weber Sandstone reservoir in the Rangely field, Colorado. A constant diffusion coefficient of 3.34 X 10-5 cm2 per sec was obtained which gives a good fit between calculated and experimental profiles determined at six times after start of diffusion. The maximum standard error of gas concentration determinations experienced with this method was ±0.88 ml per ml of gas-free oil.

Jan 1, 1970

By Kent Volkmer, Mark Sanders, Gregory Krohn, Tyler Blake, Daniel Wick, Barry Beith

This report describes a study designed to evaluate a proposed modification in the cap lamp battery cord intented to reduce the incidence of snagging and catching of the cord. A three phase evaluation as performed comparing a prototype with the standard, currently available cord. First, a "pull test" equipment was run. The second evaluation was a body conformity study. The third evaluation involved subjects performing common tasks in a low seam coal mine simulator. The results of these evaluations clearly demonstrated significant safety advantages of incorporating coiled cord into the design of the cap cord. The coil cord presented less of a snagging hazard, allowed the wearer more time to respond to a snag, and transmitted lower levels of force to the helmet when snagged. The research team recommended that cap lamp cords be commercially developed which incorporate coiled cord at the battery and helmet.

Jan 1, 1980

By A. R. Rule

Research was conducted by the Bureau of Mines to develop a process for utilization of Idaho kyanite. A continuous gravity-flotation separation process was applied successfully to recover kyanite-group minerals from an Idaho ore containing about 21 percent combined kyanite, andalusite, and sillimanite. Dry magnetic separation of the concentrate resulted in a product containing about 90 percent kyanite at a recovery of 63 percent of the kyanite-group minerals in the ore, Alumina and silica analyses were within the range generally accepted for conversion to mullite, and the finished products had a pyrometric cone equivalent of more than 38. A recovered garnet coproduct may be of commercial value.

Jan 1, 1973

By James R. Coldwell

Mining and processing cost analyses were conducted by the U.S. Bureau of Mines on stratiform zinc-lead-silver, coal, and stratiform barite deposit types that are found in the Colville Mining District. Reserves and gross revenues which would allow these deposits to be minable were modeled. A 15% Discounted cash-flow rate-of-return economic threshold was selected as the minimum acceptable return on investment for the three deposit types. The economic modeling indicated combinations of grades and tonnages for stratiform sulfide deposits that could be economically viable for orebodies ranging in size from 25 to 130 million metric tons. The gross revenues for a surface mine range from $200/mt for a 5,000 mtpd operation using the proposed South corridor to $140/mt for a 17,000 mtpd mine using the proposed North corridor. The economic modeling indicated underground coal mining was subeconomic for deposits ranging in size from 42 to 250 million metric tons. The required gross revenues ranged from $300/mt for a 2,200 mtpd mine to $21 D/mt for a 13,000 mtpd mine. The economic modeling indicated supplying projected in-state barite demand was subeconomic for the three seasonal surface mines modeled. The required gross revenues ranged from $600/mt for a 90,000 mtpy mine to $840/mt for a 6,000 mtpy mine.

Jan 1, 1995

By Paul E. Loustaunau, Devah Galloway, Catherine Wetherby

This report describes a project in which Development of a Supervisory and Management Training Program for the Underground Coal Mining Industry was developed and evaluated. The project was carried out in two phases. The first phase was a research effort to develop specifications for the program. The second phase was a development and evaluation effort. In the second phase, training programs for first-line supervisors (section foremen) and for middle managers (mine/shift foremen and mine superintendents) were prepared in accordance with the specifications and evaluated by members of the industry. This report describes the project and presents the conclusions drawn there from.

Jan 5, 1983

By Gregory J. Chekan

In order to reduce waste and improve resource conservation, mine planning, and development, the U.S. Bureau of Mines is investigating multiple seam interactions associated with longwall mining. Longwall gate entry and panel stability have been influenced by previous mining in coalbeds above and below a mine in Virginia that operates in the Lower Banner Coalbed. Directly superjacent, approximately 115 ft, the Upper Banner Coalbed has been partially worked by room-and-pillar mining. Directly subjacent, approximately 730 ft, the Tiller Coalbed has been worked by partial room-and-pillar retreat mining. The study mine has experienced problems during development of gate entries in areas of overmining and undermining. It is anticipated that stress fields associated with adjacent mining may further affect gate entry stability and face advancement during the extraction of the longwall panel. To assess overmining and undermining effects on ground stability, the Bureau gathered geotechnical information at the site. Headgate entries and pillars were instrumented and monitored to study loading behavior as the longwall face approached and passed potential problem areas. Measurements indicate that although increases in average pillar pressure were greater than predicted values, previous mining in adjacent coalbeds had little effect on headgate stability.

Jan 1, 1989

By Steve Iverson, Jeffrey C. Johnson, Henry Rodriguez, Rene Rodriguez, Michael Lhamond

To reduce fatalities resulting from personnel falling into voids formed above feeders in coal piles, the National Institute for Occupational Safety and Health at the Spokane Research Laboratory established a project to monitor coal surge piles to detect the formation of voids. A resistivity imaging method has been developed by GECOH Exploration, of Lexington, KY, in which a geophysical technique known as vertical electrical sounding (VES) is used to scan for these voids. VES operates by measuring the electrical field produced by a current in the ground at the bottom of the coal pile. This paper summarizes the results obtained from a field-scale test and shows that mapping voids within a coal pile is possible.

By John R. Benham

The Blue Joint Mtn. RARE II area may contain barite resources. One claim, the Woods Creek Barite No. 1, contains two veins of barite of drilling mud quality. The quantity of barite present could not be determined due to limited surface exposures. Sections 1, 2, 11 and 12 of T. 2 S., R. 23 W. in the study area are classified by the U.S. Geological Survey as prospectively valuable for geothermal energy resources. These sections border Blue Joint Creek Hot Springs, which are outside the study area.

Jan 1, 1981

By R. C. Gabler

Laboratory tests on a combined nitrogen roast--two-stage leach--electro-winning approach show promise as a possible process for recovering copper, sulfur, iron oxide, and valuable minor metals (gold, silver, and molybdenum) with a minimum impact on the environment. During the nitrogen roast at 800° C, 15 to 20 percent of the sulfur together with a significant fraction of the volatile elements, such as arsenic, bismuth, lead, and zinc, are removed from the chalcopyrite concentrate. The resulting calcine, consisting of 8-chalcopyrite, troilite, and a bornitelike structure, is leached with hydro-chloric acid to remove 70 to 85 percent of the iron. The digenite in the leach residue is dissolved in an oxygen-saturated, spent sulfate electrolyte. Using a graphite 'anode plus sulfur dioxide to reduce interference from ferric iron, copper of 99.99+ purity is electrowon at current efficiencies of 88 to 92 percent and a cell voltage of 0.4 to 0.5 volt. Copper recovery for the overall process is 98 to 99 percent. Sulfur is obtained in the elemental form from the roasting and leaching steps. Iron can be recovered from the hydro-chloric acid leach solution. Gold, silver, and molybdenum are concentrated in the silica residue from the spent electrolyte leach.

Jan 1, 1975

By I. F. Avery

The productive capacity of natural gasoline and cycling plants in the United States on January 1, 1956, was 46.4 million gallons per day, according to the Bureau of Mines r biennial survey. This represented an increase of 7.5 million gallons per day during the 2-year period since the last survey. In the previous 2-year period, capacity had increased 4.8 million gallons per day. The total number of plants increased from 535 on January 1, 1954, to 600 on January 1, 1956. The number of operating plants increased from 521 to 571. The major increases in capacity took place in Texas, Louisiana, New Mexico, and Oklahoma, with the absorption-type plants continuing to account for most of the new construction. All types of plants showed construction gains with the exception of charcoal which showed no change.

Jan 1, 1957

By Alex C. Smith

This report describes laboratory studies conducted by the Bureau of Mines to evaluate the effectiveness of 10 additives to inhibit the self-heating of coal. Aqueous additive solutions were applied to a bituminous coal with a high spontaneous combustion potential, and the minimum self-heating temperatures (SHT's) of the dried coal-additive mixtures were determined in the Bureau's adiabatic heating oven. The relative effectiveness of the additives was determined by the observed changes in the minimum SHT's of the mixtures, or by the time required for the sample temperature to reach 150" C, compared with the untreated coal and a coal-water blank. Sodium nitrate, sodium chloride, and calcium carbonate were found to be the most effective inhibitors, followed by ammonium dihydrogen phosphate, calcium chloride, ammonium chloride, sodium acetate, and potassium chloride. Two additives, sodium formate and sodium phosphate, promoted the self-heating process. Differential scanning calorimetry experiments on the coal-additive mixtures showed that reactions occurred between the coal and some of the additives, but these reactions did not influence the self-heating process.

Jan 1, 1988

By Wilbur I. Duvall

The Bureau of Mines presents a theoretical solution for the stresses and displacements in an infinite elastic plate containing a circular hole whose boundary is subjected to applied shear loads over four separated arcs. The results for the applied shear loads can be superimposed on the results for applied radial loads, given in a previous publication, to obtain a complete two-dimensional approximation of the stresses and displacements induced in the rock by tunnel boring machines anchored in a circular tunnel by means of four props. Analysis of the various solutions shows that the tangential tensile stresses induced on the boundary of the circular tunnel by applied radial loads can be minimized in the roof and floor of the tunnel by the application of appropriate shear loads to each of the four props. Thus when planning tunnel boring operations, consideration should be given to the in situ stress field in the rock and the induced stresses in the rock resulting from the applied radial and shear loads produced by the props of the boring machine.

Jan 1, 1968