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By Robert Lee Stahl

Comprehensive field tests were made in the Gas Hills, Wyo., to determine whether surface geophysical techniques could be used to detect and delineate faults in marginal uranium deposits. The tests were made on property owned by Federal American Partners, Gas Hills, Wyo., and included seismic refraction, self-potential, induced polarization, magnetometer, electrical resistivity, airborne infrared thermal scanning, and airborne photography. Of the several geophysical techniques tested in the field, horizontal resistivity profiling with electrode spacings in the range of 25 to 50 feet was most diagnostic of faults. The method is quick, cheap, accurate, and one that can be easily used by personnel employed by mining companies to detect and delineate faults.

Jan 1, 1973

By B. B. Letson

The heats of formation of lithium chloride and lithium oxalate were determined with the aid of a Bureau-developed, glass Dewar-type solution calorimeter which uses thermistors as its temperature sensing element. Values obtained at 298.15° K were -98.38 ± 0.54 kcal/mole for lithium chloride and -329.02 ± 0.79 kcal/mole for lithium oxalate, using graphite as the standard state for carbon.

Jan 1, 1965

By A. E. Ketler

The Bureau of Mines Research Program has defined per coal miner's illumination needs. Due to similarity in the environment in which coal and Hardrock miners work, coal mine illumination technology has been applied to Hardtack room and pillar mines.

Jan 1, 1977

By S. L. Ausmus

The work covered in this report is a continuation of an earlier feasibility study by the Federal Bureau of Mines and points out improvements in the skull-melting method for casting reactive metals such as titanium, zirconium, and hafnium. Machined graphite molds with laminated sections can be reused many times. Large tube sections can be produced by spin casting. Graphite powder is the best expendable mold material, but binders for this use must be compounded carefully. The effects of current and furnace atmosphere on the dependent variables of the casting technique are shown. Because of developments in casting technology for titanium which eliminate the basic problems of melting and pouring the metal, opportunities for improvement in the method have increased. The mold material and gate and riser configurations require particular attention. The limits of application of the casting method have yet to be defined. New knowledge in anyone of these areas could result in marked improvements and simplifications in casting methods.

Jan 1, 1960

By Daniel R. Walton

A study to explore the potential of utilizing the transport time required to move coal miners to and from the working sections. Consideration was given to all forms of training and presentation media, taking into account such environmental factors as noise, dynamic interferences, visibility, physical constraints, and contaminants. Indications of managements? and workers' attitudes toward man-trip training were also assessed. The final product was a proposed prototype training system for man-trip training. Includes Bibliography.

Jan 1, 1979

By Rees D. Groves

The Bureau of Mines conducted research on reactions of copper sulfide minerals with chlorine in an aqueous system. Selected samples of covellite, chalcopyrite, chalcocite, bornite, and pyrite were leached with aqueous chlorine solutions. The mineral samples were sized on to minus 100- plus 325-mesh, individually mixed with precleaned sand and leached in an enclosed percolation column. Each mineral was leached in stages to achieve about 90 percent mineral dissolution. The chlorine leaching solutions were produced by reacting sodium hypochlorite with hydrochloric acid within the closed system. The study showed that when the mineral dissolution was complete, the reaction products (copper, iron, and sulfur) were in their highest oxidation states and a stoichiometric amount of chlorine was consumed. Although elemental sulfur formed as an intermediate product, it was oxidized to sulfate during the leach.

Jan 1, 1973

By Ruth F. Brinkley

Principle activities of the Bureau of Mines Explosives Research Laboratory from July 1, 1960 to June 30, 1961 are reviewed briefly in Part 1. Part 1 also includes data obtained in connect ion with several minor investigations which are not sufficient to warrant separate publications. Part 2 gives brief abstracts of publications that appeared during fiscal year 1961; in general, the research reported in these publications antedates this period.

Jan 1, 1963

By E. K. Stanek

This volume describes software developed for programmable calculators that is useful in the analysis and design of mine electrical power systems. The programs are equally useful for any industrial or commercial power system. All programs are written for both the HP-97 and the TI-59 programmable calculators. Listings of both versions of the twelve programs that were developed appear in the report. The programs that were developed can be broken into two groups. The first group encompasses design-oriented programs. The second group encompasses analysis programs. For each program the following items are provided: a description of the program's capabilities, the solution technique used, instructions on how to use the program, a worked out example with data and results and, finally, listings of the programs for the HP-97 and TI-59 programmable calculators. Typical problems that can be attacked with these programs include ground bed design, selection of contactor size, fuse size, relay settings, instantaneous overcurrent trip settings for trailing cables, allowable cyclic cable loading, short circuit analyses, prediction of transient voltages and others.

Jan 1, 1979

By W. W. Graff

This paper describing the mining practices at Mine, No. 4 on the Marquette range, Michigan, is one of a series of articles on mining methods and practices in various mining districts in the United States. Mire No. 4 is located in the Swanzy district, in the southern end of the Marquette range, about 3 miles from Gwinn, Mich. The Swanzy district is an isolated ore-bearing formation, and Mine No. 4 is at the extreme southeastern end.

Jan 1, 1930

By Robert J. Hundhausen, GEORGE M. GRISMER

This circular describes the methods and costs of deepening the Silver Summit three-compartment shaft in the Coeur d'Alene mining region of Idaho. A noteworthy rate of advance was achieved at this operation by the successful use of a mechanical shaft-mucking machine. The Silver Summit mine is 1 mile west from the town of Osburn, Idaho, via U. S. Highway 10. The adit-level portal of the mine is on the south slope of the Coeur d'Alene River Valley at an altitude of 2,700 feet. The Silver Summit shaft is 6,000 feet from the portal. In past years this shaft had been sunk from the adit level to a depth of 1,500 feet. During 1946 the Polaris Mining Co, deepened it to 3,095 feet. The work was done under a co- operative development agreement between the Silver Summit Mining Co. and the Polaris Mining Co.

Jan 1, 1948

By Tyler Blake

This report describes a study designed to evaluate a pro-posed modification in the cap lamp battery cord intented to reduce the incidence of snagging and catching of the cord. A three phase evaluation was 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

INTRODUCTION The pager phones used in many underground coal mines are battery- operated, party-line telephones with provisions for loudspeaker paging. The system is two-wire, non-polarized, and is operated by self-contained batteries. Many of the individual units are certified as permissible. Requirements for installation are specified in state and federal regulations, such as in the Code of Federal Regulations, Title 30, Mineral Resources, Part 75. The major federal regulations that affect communication in coal mines are noted below, with a brief description of the subject matter in each of the relevant paragraphs. Refer to the cited paragraphs of Title 30 for explicit details of these regulations. (This brief description is for reference purposes only.) Minimum Requirements (paragraphs 75.1600, 75.17 13-2, and 75.1003-1) Approved telephone or two-way communication will be provided between the surface and each main shaft landing and each working section ; to the nearest medical assistance; and shall be protected from contact with trolley wires or trolley feeder wires. Installation Requirements (paragraphs 75.5 16-2, 75.52 1, and 77.508-1 ) Communication wires will be supported on insulated hangers, attached to messenger cables, or buried, to protect against mechanical damage ; installed opposite trolley wires; and insulated near power conductors . . . each cable will have lightning arresters within 100 feet of going below ground . . . and arresters will be provided wherever telephone wires enter a building. Wire and Cable Requirements (paragraphs 75.5 16-2, 75.5 17, and 75.52 1) Communication cable means two or more insulated conductors, covered by an additional abrasion-resistant covering; power wires and cables shall be adequately insulated and fully protected; and lightning arresters shall be connected to low-resistance grounds, more than 25 feet from neutral grounds.

Apr 1, 1975

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine the hydrogen cyanide (HCN) concentrations and smoke particle characteristics during the combustion of flexible polyurethane foams and other nitrogen-containing materials, for the development of a test parameter. The experiments were conducted in an approximately 2O-L furnace at set furnace temperatures of 250° and 1,000° C for a 14-min duration, with an airflow through the furnace of 10 L/min. The variables studied as a function of time were the gaseous and aerosol HCN concentrations, the smoke particles average diameter (dg) and particle concentration (no), and the product of the smoke particle diameter and concentration (dgno). Carbon monoxide, carbon dioxide, and oxygen concentrations, sample mass weight loss, and furnace temperatures were also studied; analyses of nitrogen and cyanate content of the material were carried out. Results show that dgno correlates directly with the HCN concentrations, which depend on the nitrogen and cyanate contents of the material.

Jan 1, 2010

By H. Netuka, J. V. Horak, A. W. Khair

"A general review of major problems concerning mathematical modelling of roof bolting problem is given. A mathematical model (MM) of interactive set Bolt - Resin - Rock and its discretization based on the Finite Element Method (FEM) is developed to calculate numerically course of displacement, stress and strain fields in this set. This new MM enables to get also course of the normal and tangential components of contact stress vector, normal displacement and then mutual tangential slip at the bolt - resin and resin - rock interfaces, respectively.Behavior of system on all interfaces is modelled in the MM as a ""unilateral contact"" governed by so called non-classical boundary condition of Signorini's type including Coulomb's law of friction between resin and rock, and ""a given friction"" law between bolt and resin (see Duvaut, Lions (1972) for mathematical formulation).Numerical example and some values of resulting stresses are shown and remarks on necessary and sufficient conditions for solvability of the problem are also given.IntroductionAs is well known roof bolting has become the primary support system in almost all underground coal mines. But the ""theoretical"" design criteria for roof bolt patterns are rather problematic because: "" ... real mechanisms by which the roof bolts reinforce the immediate roof of underground coal mine entry are still relatively unknown"", see Peng (1986).The aim of this contribution is to present brief description of fundamentals of mathematical theory (see Hlavacek et al., 1988) which could be, according to our opinion and knowledge, very helpful for numerical modelling of a such type of problems. For the sake of brevity we restrict ourselves here to just one of the simplest possible problem: analysis of the behavior of interactive set composed by only single full - length - grouted bolt, resin (or cement) and suitable part of domain of a ""immediate"" neighborhood of bolt which should represent physical action of real rock material."

Dec 1, 1995

By T. L. Joseph

The size and accessibility of the Minnesota manganiferous iron ore deposits make them attractive as a potential source of ferromanganese, which is essential in the production of steel. For several years the Bureau of Mines has been conducting experiments to determine the feasibility of producing ferromanganese from these ores by a three-step process which involves (1) the smelting of the ores in the blast furnace to produce a high-phosphorus spiegel; (2) the treatment of the spiegel produced from step 1 in an electric or open-hearth furnace to separate the manganese from the phosphorus and the iron; and 3) the smelting of the high-manganese slag from step 2 to produce ferromanganese. The details of the first two steps of the process and the results of tests with the experimental furnaces have been given in previous reports.

Jan 1, 1931

The Technology Transfer Seminar on Mine Communications held on March 21-77, 1973, at the Pittsburgh Mining and Safety Research Center, Bruceton, Pa., presented information about recently developed equipment, instruments, and techniques for use in mine communications systems. All of the basic ideas presented in the fine seminar are operational in the Bureau of Mines Safety Research Mine in Bruceton.

Jan 1, 1974

By Earle S. Burnett

Rotating piston deadweight gages have been used for many years for measurement of pressure to several hundred atmospheres. They have been calibrated by comparison of fluid pressures produced by various loads bearing on the piston bases, as measured by corresponding heights of balancing columns of mercury. When expressed in appropriate units, these ratios of column heights to piston loads are called piston constants. Experimental arrangements and procedures for their determination are presented in this paper, followed by a discussion of their significance and of their subsequent applications.

Jan 1, 1966

By Donna lynne Anderson

This report documents the status of a laser-based underground guidance system for tracking and controlling the movements of underground mobile mining equipment. This research is part of a multiple project effort at the U.S. Bureau of Mines to increase mine safety and efficiency by developing technology for computer-assisted mining. Guidance systems, which can track and control the movements of underground mining equipment, are essential during computer-assisted mining operations. A continuous mining machine at the Bureau's surface test facility served as the test-bed for initial development and experimentation of this guidance system. Subsequently, a continuous mining machine in an underground mine served as the platform for in-mine experimentation. The first section of this report includes details of the laser sensors, communication network, and computer hardware. The next section includes experimental results, which show the system capable of accurately tracking and controlling the tram maneuvers of a continuous miner underground. The final section discusses conclusions and recommendations.

Jan 1, 2010

By Thomas M. Barczak, Joe Bower, Jinsheng Chen

Pumpable roof supports provide an alternative longwall tailgate roof support and have grown in usage during the past few years. Heintzmann Corporation has been installing pumpable roof supports at the RAG Resources Emerald Mine in western PA since 1998, where they have provided effective roof control in their longwall tailgates. Despite the success of these supports in this application, questions remain regarding critical design issues for optimizing the use of this support technology. The support loading profile is characterized by a high initial stiffness with peak loading occurring at less than one inch of convergence, followed by significant load shedding with a post failure capacity comparable to that of wood cribbing. Therefore, the key to optimizing the support utilization is to provide sufficient load density to prevent convergence from occurring beyond the peak loading capacity. This requires an understanding of how the supports interact with the ground conditions, hence measurement of the ground reaction curve. In order to obtain this information, pumpable roof supports were instrumented to measure support loading. Roof deformation and roof-to-floor convergence measurements in the vicinity of the instrumented supports were also made. The experimental parameters for the installation were the support spacing and water-to-solids ratio of the grout, which controls the grout strength and ultimately the maximum capacity of the support. The study clearly shows that at this mine a 24-inch diameter support is fully capable of providing adequate ground control under depths of cover of 750 ft as only 50 pct of the available support capacity was utilized outby the longwall face. It was also shown that the 2.00 to 1 water-solids ratio, despite providing a slightly softer support response, is sufficient for maintaining the same degree of roof control provided by the traditional 1.75 to 1 grout mix. The 10-ft spacing of the supports did not cause any ground control problems outby the face. However, inby the face the performance of the support is degraded once the peak capacity of the supports is exceeded. It appears that the large load shedding behavior, which is characteristic of this support following peak loading, allows the immediate roof to separate. When this happens, the support is unable to regain control of the roof in time to prevent failure of the immediate roof beam.

By Jeffrey Shawn Peterson

The testing procedures of the U.S. Mine Safety and Health Administration specify that intrinsic safety acceptance tests be conducted using a standard tungsten-cadmium electrode configuration in the break- flash apparatus. However, in realistic mining environments, other materials may be more likely sources of sparking. Information defining the probability of spark ignition between common materials such as aluminum, brass, copper, lead, tin, cold-rolled steel, and stainless steel is of more practical value in determining ignition hazards. The U.S. Bureau of Mines has completed an investigation of the influence of material on the ignition probability using the breakflash apparatus. By comparing ignition currents or ignition voltages corresponding to a probability of one ignition per thousand sparks to those found previously for cadmium, a margin of safety may be estimated for each material. This report presents the results of an investigation into the influence of disk electrode material on the probability of ignition.

Jan 1, 2002