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By John P. Gooch

Data for the ternary phase diagram for the system 1,1,2,2-tetrabromoethane/water/2-propanol at 25° C have been measured. Experimental methods used are described, and the complete ternary phase diagram is presented. A simple example is given to review the use of the ternary diagram.

Jan 1, 1972

By Larry J. Nicks

The Bureau of Mines is investigating the catalytic activity of rare-earth compounds to develop a catalyst for the cathode reaction of a hydrogen-oxygen fuel cell. This report presents the results of studies of the catalytic activities of lanthanide oxides for the oxidation of hydrogen at 150° to 250° C. Preliminary activity tests were made with approximately stoichiometric mixtures of hydrogen and oxygen diluted with helium. A series of tests was also run under oxygen-rich conditions in which specific rate constants and activation energies were determined. Variations in rate constants up to 2,000 times were observed for the various lanthanide oxides. The three most active catalysts were oxides of Ce, Pr, and Eu, having specific activities of 6.93 X 10-7, 4.88 X 10-7, and 4.06 X 10-7 moles H2.sec-1.m-2, respectively, at 200° C.

Jan 1, 1973

By H. H. Dewing

The Bureau of Mines conducted a laboratory-scale investigation of a technique that produces zinc sulfate and elemental sulfur from sphalerite concentrates by reaction with sulfuric acid at 175° to 200° C and ambient pressure. The objective of the investigation was to develop a hydrometallurgical method of producing zinc from sulfide concentrates that does not generate sulfur dioxide pollutants. Reaction with 80-to 85-pct sulfuric acid produced 4 moles of sulfur for every 3 moles of sphalerite reacted, with minimal production of sulfur gases under optimum conditions. More than 98 pct of the zinc was recovered as zinc sulfate after 3 hours at 175° C. The reaction mixture was leached with simulated spent zinc electrolyte containing 13-pct sulfuric acid to recover zinc sulfate from the insoluble, high-sulfur residue. Neutral zinc sulfate, which is required for electrolysis, was separated from the sulfuric acid solution by crystallization as ZnS04?7H20 at -10° C. Up to 80 pct of the water in the recycled electrolysis solution was removed by the crystallization process; evaporation was used to further concentrate the sulfuric acid for reuse in leaching sphalerite. Advantages of the proposed method over conven-tional roasting and leaching include virtual elimination of sulfur dioxide, production of a solid sulfur byproduct, and higher zinc recoveries due to elimination of zinc ferrite losses.

Jan 1, 1978

By Jamie Girard Dwyer, Edward McHugh, Stanley Miller, Jeffrey Whyatt

This user's guide covers the operation of a suite of three computer programs-Bplane, Bstepp, and Bwedge. These programs can be used to evaluate the potential for plane shear, step-path, and wedge failures along the crest of a slope bench. Such failures reduce the width of a catch bench and may compromise the bench's ability to catch rolling or sliding material before it reaches miners working below. The Bplane and Bwedge programs address sliding of blocks defined by continuous planar joints. The Bstepp program examines sliding of blocks defined by more complex failure surfaces that include steeply dipping cross joints and may even include breaks across small bridges of intact rock. The programs are applicable to jointed rock masses where the joints are small relative to the overall slope and form a number of sets with uniform statistical characteristics within a slope sector. The theoretical basis, application, and operation of these programs are described.

Jan 3, 2007

By M. L. Davis

The principal causes of many methane-gas explosions that have occurred in anthracite mines, especially in thick pitching veins, during recent years can be traced to lack of a satisfactory method of testing for such gas in areas adjacent to those in which blasting is to be done or other sources of ignition introduced. As coal-mine officials and inspectors are required to make examinations for methane in all accessible open workings, including high places, and permissible flame safety lamps have been used almost universally for making these examinations, considerable difficulty has been experienced in proper testing of atmospheres at elevations beyond the normal reach of the examiner, and resultant explosions have often indicated perfunctory tests. The accepted practice of testing for gas in voids or high places generally consists of raising a flame safety lamp, suspended from the end of a long drill, stick, or pipe, into the atmosphere to be tested. Disadvantages noted are: Action of the flame within the lamp cannot be seen readily when the lamp is more then 18 inches overhead, the flame will not be extinguished when less than about 4-1/2 percent of methane is present, and indications of small percentages of methane within the lamp may disappear entirely while the lamp is being lowered slowly to view; the examiner must usually be exposed unnecessarily to falling material; and the lamp may fall and be broken. Thus, the need for a more reliable, safe method of testing for gas in out-of-reach places is apparent. Several electrical methane detectors, tested and approved by the Bureau of Mines, have been used satisfactorily, though infrequently, for making the aforementioned gas tests. Some of these detectors employ a rubber aspirator bulb and rubber tubing of suitable length to draw the atmosphere from high places through and over energized parts of the detector. However, the original expense, susceptibility to damage, and awkwardness of tarrying these instruments in steep-pitch workings has precluded their general use in everyday examinations. Although not as efficient as the electrical detector for determining small percentages of methane or as reliable because of the limitations imposed by oxygen-deficient atmospheres, the modern per¬missible flame safety lamp can, it is believed, be used safely with the rubber aspirator bulb and tubing to greater advantage and with comparative reliability in testing for gas in out-of-reach places. Slight reference to this method of introducing air into a safety lamp is made in a Bureau of Mines publication of l921,2/ and it is quite possible that the method has been utilized in some manner by individuals in American mines during the intervening years. A similar method was used in connection with a nonpermissible Wolf flame safety lamp in at least one coal mine in Japan before World War II. A major change in the construction of this lamp would bar its approval by the Bureau of Mines. An American adaptation of the Wolf lamp, developed

Jan 1, 1954

By D. D. Bolstad

The Bureau of Mines has developed procedures for sampling the geometry of fractures in underground coal mines. Stratified cluster sampling and the unit area concept are applied to the collection of fracture orientation data. The use of unit area mapping, stratification, and site delineation is made to assure collection of representative data. The procedures developed here help to isolate sources of variability in the fracture patterns.

Jan 1, 1973

By T. T. Campbell

This report describes the development of new electroplating baths from which tin-nickel alloy plate was deposited. Although tin-nickel plate can be deposited from an aqueous ammonium bifluoride bath, the corrosive nature of this bath has served as a deterrent to its use. The Bureau of Mines felt that more general acceptance of this new alloy plate would follow if neutral or alkaline baths could be developed. Promising results were obtained from electrolytes containing both tin and nickel chlorides dissolved in triethanolamine-hydrochloric acid or in ethylene glycol hydrochloric acid baths. Current efficiencies close to 100 percent were obtained with these baths. Research revealed that tin-nickel plate could be produced from organic solvents or from mixed aqueous-organic electrolytes. The composition of the alloy deposit - 65 percent tin and 35 percent nickel - was found to exhibit the same single-phase structure that is obtained from the commercially accepted fluoride-type bath.

Jan 1, 1959

By E. J. Gleim

Many people consider the mining of coal to be an extremely hazardous occupation; but it should be remembered that most large industries have to meet special conditions which, if not dealt with properly, might become hazards to life and property. Mining men may not always be fully aware that some practices and certain equipment that is incorrectly designed or maintained can lead to dangerous conditions. In endeavoring to help the coal-mining industry to prevent accidents and disasters, the Bureau of Mines has engaged in a program of education on conditions and practices that must be avoided. An effective way to teach safety is by visual demonstration. For example, it is generally known that certain kinds of electrical flashes have ignited explosive atmospheres in mines, but actually to see and hear explosions caused by electrical sparks of different size and character under laboratory control is likely to teach a much more emphatic and lasting lesson than would be learned by merely reading about them. The interest manifested by those who witness the demonstrations seems to prove that this is true. The purpose of the demonstrations is not to discourage the use of electricity in mines, but rather to indicate what types of equipment (including some generally regarded as harmless) can ignite gas and what safeguards have been developed to prevent such ignitions. It is hoped that this information will improve the ability of mining men to cope with underground hazards.

Jan 1, 1937

By T. J. Lutz, G. T. Homce

A standard Ford1 4600 agricultural tractor was converted to remote control to perform ASAE/SAE field upset tests (rear rollover and side rollover). This paper discusses the engineering process to develop a remote-controlled tractor in determining the critical parameters of operation, to choosing appropriate actuators, designing the circuitry to control them, installing the actuators on the tractor, testing the system for functionality and then conducting numerous overturn tests. The system uses off-the-shelf components for simplicity, replaceability, and economic concerns. The remote control system has withstood 21 tests to date with no failures and will continue to be used for at least three more years of testing.

To reduce front-end loader (FEL) collision accidents by detecting obstacles in the rear blind area. The Problem Federal regulations require an audible backup alarm to activate when an FEL is backing. Since the device is constantly being activated, the warning soon becomes a normal part of the mine environment and is less effective as a warning device. Also, when several machines are working together, it is difficult to detect by ear alone just which machine is backing. Approach The Bureau defined the location for hazard detection to include an area extending 15 to 20 ft behind the rear bumper of an FEL. Then, existing surveillance and detection technology was assembled, ruggedness, and applied to the FEL's rear blind area to form a new discriminating backup alarm system employing either infrared light, ultrasonics or radar

Jan 1, 1986

By B. J. Scheiner

Carbonaceous gold-bearing ores of the type that occur in north-central and northeastern Nevada were investigated by the Bureau of Mines as part of its Heavy Metals Program. Specific objectives were to identify the carbon and organic compounds that prevent adequate gold recovery from the ore by cyanidation and to develop an economical process that would overcome the detrimental effect of the carbonaceous constituents. Activated carbon and long-chain organic compounds containing sulfur and nitrogen were found in the ore. Part of the material consisted of stable gold organic complexes. A mild oxidation technique that allowed gold extraction as high as 96 percent by subsequent cyanidation was developed. A variety of oxidants was shown to be effective in improving gold recovery, including chlorine and sodium hypochlorite (NaOC1). An electrolytic oxidation process was developed that was particularly advantageous from an economic and effectiveness standpoint.

Jan 1, 1971

By Charles Vaught

This paper discusses the fact that US coal mining organisations are losing the knowledge they need in order to be able to respond to emergencies. The authors note that knowledge management provides a useful perspective from which to view the problem, but that the debate about what constitutes knowledge should be broadened to include a debate about what constitutes management. It is argued here that knowledge is actually shared knowing distributed across group members; that such knowledge can be managed by cultivating it; and that narrative is the medium through which this may be done. The paper then examines NIOSH research that has attempted to use such an alternative knowledge management approach to help potential mine emergency responders better deal with the predicaments they are likely to encounter on-site.

Jan 1, 2006

Develop a curved ray geotomographic program with constraints to counteract non-uniqueness in order to improve the reliability of seismic tomographic imaging of geological structure in mining regions. Background Seismic tomography provides a two-dimensional image (tomographic reconstruction) of the distribution of the seismic velocity in geologic structures using measured travel times of seismic waves crossing the area. It can provide a more complete representation of features be¬tween boreholes than other crosshole processing methods that measure only average properties or borehole logging methods that measure properties only near each borehole. Seismic tomography has many mining applications. They include locating geologic structures of contrasting seismic velocity, detecting fractured regions where the seismic velocity is low, and monitoring solution injected above the water table where the increase in saturation increases the seismic velocity. Thus, tomographic imaging techniques show great promise for detecting and locating geologic hazards that affect the productivity, safety, and environment of mining operations.

Jan 1, 1992

By Dennis Cox, Stephen P. Signer, Joanne Johnston

A method to assist in the evaluation and selection of roof bolts using in situ measurements of roof bolt loading has been developed by researchers of the Spokane Research Center, National Institute of Occupational Safety and Health. Both axial and bending forces are measured by strain gauges at many locations along the length of fully grouted bolts during various stages of mining. This information is then used to (1) predict bolt loading for variations in bolt spacing, grade, and diameter, (2) calculate the design changes necessary in zones where bending loads are high, and (3) determine if bolt length is adequate. Results from several case studies of full-column bolt loading in coal mine gate roads are used to illustrate the design method. This knowledge will give design engineers a tool for the selection of roof support systems that will improve underground safety by reducing roof bolt failures.

By Gary L. Mowrey, William D. Monaghan, George F. Persetic, Gregory M. Molinda

Ground penetrating radar (GPR) has been investigated by the U.S. Bureau of Mines Pittsburgh Research Center for its potential to determine rod hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth to determine the value of GPR for roof hazard detection. The resolution of the current systems allows detection of gross roof fractures (>6A mm (>0.25 in) zone) or rider beds in coal measure roof. Data quality is not yet sufficient to detect small bed separations or subtle lithologics changes in the roof. Differences in data quality are discussed, as well as suggestion for collecting improved data.

Jan 1, 1996

Reduce dust generated during bagging at minerals processing facilities, such as silica sand operations. Approach Installation of a new type of bag nozzle system eliminates the major dust sources during the bag filling process. How It Works The drawing illustrates components of the new bag nozzle system. The system differs in several ways from the conventional nozzle system. An improved bag clamp reduces the amount of blow-back during bag filling, because it has direct contact with approximately 80 per-cent of the nozzle. A two nozzle arrangement includes an inner or "fill" nozzle surrounded by another nozzle, which is designed to exhaust excess pressure from the bag after it has been filled. The exhaust is powered by an eductor, which uses a venturi effect to exhaust the bag at approximately 50 cfm. The exhaust exits into a bucket elevator and is recycled. A pinch valve automatically opens and closes the exhaust system to the bag.

Jan 1, 1984

By Fun-Den Wang

A new approach for evaluating pit slope stability by the limiting equilibrium method has been developed by the Bureau of Mines. The finite element method of plane strain analysis is used to find the stress field of the pit slope structure. This stress field is then used to find the normal and shear stresses along a potential failure surface. The normal stresses are used with the Coulomb equation to calculate the shear resistance. The shear stresses are integrated to determine the total driving force. The factor of safety is evaluated from the ratio of the resisting force to the driving force along a failure surface, and is found to be affected by the elastic material properties, modulus of elasticity, and Poisson's ratio.

Jan 1, 1970

Montana's coal reserves are estimated to be more than 120 billion tons, 24.6 percent of U.S. reserves. Montana's reserves are the largest in the nation. Coal fields are located throughout the state, primarily east of the Continental Divide. Three of the state's 17 coal fields have producing mines. Coal resources range from lignite to high volatile bituminous; however, most of the coal currently mined is subbituminous. Although Lewis and Clark mentioned the presence of coal along the banks of the Missouri River in Montana in 1805, the first major mine was not opened until 1867, at Chestnut, Montana, near Bozeman. The mine at Chestnut served Fort Ellis until the mine was bought by the Northern Pacific Railroad in 1883. By 1900, underground coal mining had developed throughout the state, primarily to supply fuel to the railroads. In the 1920s, large-scale surface mining began in Colstrip to fuel railroad steam engines. Currently, all coal mined in the state is produced from surface mines. The Office of Surface Mining granted the Montana regulatory program conditional approval April 1, 1980, followed by final approval February 1 1,1982. Montana's Abandoned Mine Lands Program was approved November24,1980, and its emergency program was approved August 18, 1983. A Federal Lands Cooperative Agreement was approved May 8, 1981.

Jan 1, 1992

By Harold J. Bennett

This report deals with the processing and marketing of iron and steal scrap in the intermountain States of Arizona, Colorado, New Mexico, Utah, and Wyoming and the northwestern Plains States of Nebraska, North Dakota, and South Dakota. The quantity and quality of iron and steel scrap consumed in both the steel mills and iron foundries in these States in 1964 were decided by (1) the type of facilities used to produce an end product; (2) the availability of a dependable source of iron and steel scrap at competitive prices; and (3) the, ratio of the cost of iron in iron ore to iron in scrap. In recent years the quantity of scrap used per ton of steel ingot produced has decreased. The major individual. consumers of iron and steel scrap were the steel mills in Arizona, Colorado, and Utah, foundries in Utah and Arizona, and copper leaching, operations in Arizona, New Mexico, and Utah. About 2 million tons of iron and steel scrap was used by the iron and steel industry in 1964. Although there has been a decline in the amount of scrap used per ton of steel ingot produced because of changes in steelmaking methods, there has been a slight increase in the overall quantity of scrap used because of the increase in ingot production. It is estimated that the scrap consumption in the steel industry will increase by 19 percent by 1980. In addition to the scrap consumed by the steel industry, 273,000 tons of ferrous scrap were used by copper-leaching operations. Thirty-one percent of the ferrous scrap used by the steel industry in 1964 was purchased from dealers and other sources. The CF&I Steel Corp. (formerly The Colorado Fuel and Iron Corp.) at Pueblo, Colo., complemented its blast- and open-hearth-furnace operations with basic-oxygen converters in 1962. The basic-oxygen and open-hearth furnaces were charged with 30 and 90 percent scrap, respectively. Future use of the open-hearths would probably be used to supplement ingot production requirements. Because it was more economical to use less scrap and a high molten-metal charge, the United States Steel Corp. at Geneva, Utah, which uses the open-hearth process to make steel, charges the furnaces with 25 to 35 percent scrap. The Allison Steel Manufacturing Co. at Tempe, Ariz., uses a 100 percent scrap charge in its electric furnace. Although it was estimated that there were 327,000 tons of various grades of motor vehicle scrap generated in 1963, no estimates were made concerning the total quantity and grade of scrap available in the area. Most of the scrap used in the steelmaking industry originated within the area. It was advantageous to sell scrap generated in eastern Nebraska, North Dakota, and South Dakota to markets in the Midwest because of freight costs.

Jan 1, 1967

By H. J. Fissan, G. Ananth, K. Rubow, V. Marple

"INTRODUCTION Over the past several years a new type of cascade impactor that utilizes small nozzle diameters (micro-orifice nozzles) has been under development (Kuhlmey et al., 1981; Marple et al., 1981). The small nozzle dimensions allow for particles to be collected as small as 0.024 µm aerodynamic diameter on the last stage of the impactor. To obtain a reasonable flow rate of 30 I min - i through the impactor, a large number of nozzles (up to 2000) are required per stage.Furthermore, by locating the nozzles of multi-nozzle stages in a prescribed manner (described in detail by Marple et al., 1981) and rotating the impaction plates relative to the nozzle plates, uniform deposits can be achieved on the impaction plates. As described by Marple et al. (1981), the advantages of a uniform deposit impactor over the conventional impactor that collects particles only beneath stationary nozzles are: (1) maximum use of the impaction substrate surface, reducing both particle bounce (if substrates are greased) and tare weights of the substrates (if particle mass is measured gravimetrically); (2) deposited particles can be analyzed for elemental composition by X-ray fluorescence (Dzubay and Rieke!, 1978); and (3) the pressure in the impactor can be kept relatively high compared to low pressure impactors that depend on a large slip correction to achieve small particle collection (some types of particles may evaporate at low pressures). The work described in this paper investigates two additional advantages of a uniform deposit impactor. These are: (1) the possibility of collecting two separate deposits at one time on one stage for two types of analysis techniques, and (2) the possibility of utilizing piezoelectric quartz crystal impaction plates more effectively by eliminating the deposit location sensitivity nature of the crystals (Schulze-Frohlich, 1981 ).MICRO-ORIFICE UNIFORM DEPOSIT IMPACTOR (MOUDI)A photograph of an eight-stage MOUDI is shown in Fig. 1. Each stage body of the impactor supports the impaction plate for the stage above and the nozzle plate for the stage below as shown in Fig. 2. By rotating alternate stage bodies, while holding the other stage bodies stationary, the impaction plates (or nozzle plates) will be rotated relative to the nozzle plates (or impaction plates).Rotation of the alternate stage bodies is achieved by gears on these bodies that mesh with gears on an electrically driven drive shaft of a rotating mechanism (Fig. 1 ). The alternate stage bodies are restrained from rotation by pins that rest on the drive shaft."

Mar 1, 1989