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Note: This is a progress report and therefore not necessarily conclusive. Further data may result in conclusions somewhat different from those reported here. Crop Growing Season The monthly average temperatures, total precipitation, and evaporation for the demonstration mine are shown in Table 1. [ ]

Jan 1, 1980

By G. L. Anderson

The critical importance of wire rope integrity to the mining industry has led to the creation of standards for the retirement of wire rope as well as to the development of electromagnetic devices and procedures that would allow wire ropes to be tested against these standards without destroying them, The U.S. Bureau of Mines (USBM) conducted research to evaluate these devices by measuring loss of metallic cross-sectional area and the number of wire breaks, or local faults. The intent was to define the extent to which the technique can identify degradation within the rope, e.g., broken wires, corrosion, and wear. Experimental results showed that instrument sensitivity depended on a number of factors, including rope diameter, placement of sensors, location and characteristics of flaws, rope speed, and tension on the rope. The experiments also demonstrated the importance of having an elongated recorder trace and a properly trained and experienced operator to interpret overall results. A design of a rope and test procedures for use in laboratory evaluation of instruments have been recommended by the American Society for Testing and Materials Committee E07.07.10, Wire Rope Applications. The USBM is working through this committee to develop standards for an electro-magnetic method of wire rope inspection.

Jan 1, 2010

By N. E. Hanna

As part of a program for improving, the safety of permissible explosives, the Federal Bureau of Mines has undertaken an investigation to establish the ability of sodium chloride to reduce the incendivity of permissible explosives to firedamp atmospheres. A motivating influence for this investigation has been the comparatively extensive experience of British and other European investigators, who used sodium chloride as a component of their permitted explosives (1, 5, 6 7).5/ In the United States research and development work of this type has been less extensive, although sodium chloride has been added to permissible explosives as a cooling agent (9) for many years. The results of the first phase of this investigation were presented in a previous paper (8), which established that adding up to 10 percent sodium chloride to permissible explosives reduces the likelihood of ignition of firedamp in the gallery test; however, the results were somewhat inconsistent, and the conclusions were qualified. Accordingly, the investigation was continued with a study of the effect of added sodium chloride as a function of the quantity added and of the particle size of the salt.

Jan 1, 1960

By G. W. Jones

"INTRODUCTION As part of its work in promoting safety, the Bureau of Mines is investigating various means of eliminating or mitigating the explosion hazards of combustible gases encountered in mining and industry. Information has been obtained and a procedure developed whereby the explosibility of many complex gaseous mixtures may be calculated in a rather simple manner without the necessity of performing laborious laboratory experiments. An earlier publication 3/ described the method of determining by calculation the limits of inflammability of gaseous mixtures, including methane, hydrogen, carbon monoxide, nitrogen, carbon dioxide, and oxygen. The information published in the above report permitted calculation of the limits of inflamnability of such gases as are liberated by mine fires, gases from explosives, automobile exhaust gases, gases present after mine explosions, blast-furnace gas, and other gases of similar type.Gases liberated in certain potash mines in the western part of the United States sometimes contain ethane, in addition to the gases named. An investigation was made to obtain data from which the limits of inflammability of such gaseous mixtures could be determined by calculation. 4/Similar data have been Published covering all types of natural gases containing wide ranges of concentration of nitrogen and carbon dioxide.5/"

Dec 1, 1944

By Charles Vaught

The purpose of this study was to determine mine workers' state of fie-fighting preparedness and the technology being used to detect and respond to underground coal mine fires. To investigate this problem, 214 underground coal miners were interviewed by U.S. Bureau of Mines researchers. Frequency distributions of workers' responses are presented in this report, along with segments of narrative accounts, to profile miners' fire-fighting capabilities. The data indicated that much variability exists from mine to mine and that there are several important changes operators may undertake in order to make miners better prepared to deal with fire underground: select appropriate sensors, establish and test a warning and communication protocol, construct a system capable of delivering hundreds of gallons of water per minute for sustained periods, institute formal fire preparedness audits, develop case studies of events that occur at an operation to use as teaching and assessment tools, and provide structured practice that can be incorporated into fire drills.

Jan 1, 2010

By D. A. Elkins

Design plans and detailed cost estimates of mining and treating ore from Maggie Canyon deposit by two alternative methods which can be used in the event of a sudden need to exploit this resource are given . Lower costs are estimated for the operation employing oil - emulsion flotation . The total capital investment required for this operation is estimated at $ 11,750,000 . Assuming an 85 percent recovery in mining , 55.6 pct of the manganese in the ore reserve would report in 153,333 tons of ferromanganese containing 75 pct manganese . The production cost for the 5 - year operation would be about $ 245 per ton of ferromanganese . The total annual operating cost would be approximately $ 7.5 million , distributed , in pct , as follows : Mining 11.9 , milling 24.4 , sintering 9.9 , smelting 47.2 , hauling ore and sinter 2.8 , and general offices 3.8 . Recovery and costs are both higher for the operation employing dithionate leaching . In this operation the required investment is about $ 17,220,000 . Manganese recovery would be 67.6 pct in 186,160 tons of ferromanganese . Production cost would be about $ 284 per ton of ferromanganese . The total annual operating cost would be about $ 10,575,000 , distributed , in pct , as follows : Mining 8.4 , milling 44.4 , sintering 7.4 , smelting 34.7 , hauling ore and sinter 1.3 , and general offices 3.8 . Potential process modifications might reduce the operating cost of the first operation by as much as 7 pct and that of the second operation by as much as 9.5 pct , but exploitation of the deposit by the techniques studied is not economical today .

Jan 1, 1964

By R. S. Dewey

The purpose of this study was to assess the various aspects of public safety related to the thousands of abandoned or inactive underground mines found throughout Western Colorado. Review of available published mine inventories yielded data on over 8,000 abandoned underground mines. A random sample of 200 mines was then selected for field visits representative of mining activity in Colorado. Inspections of the openings at two hundred abandoned underground mines were performed recording descriptive information regarding the opening, the mine site, the surrounding area, the primary opening hazard, secondary hazards related to structures or dumps, other openings to the same mi ne, available construction materials, possible safeguard methods, and any special observations such as apparent activity, previous closure attempts, environmental constraints on construction, and access problems. Of the 200 mines visited, twenty mine openings representative of varying geologic, environ-mental, access, and mining conditions were selected for detailed low-cost safeguard application. Description of these safeguards is presented in narrative, itemized labor-materials equipment tabulations, and illustrations. Research into the regulations of mine closure and safeguards was also undertaken to determine jurisdiction of public lands. Recommendations were suggested to improve the awareness and ability to continue this program into an implementation stage.

Jan 1, 1980

By H. M. Cooper

The determination of moisture in coal is an empirical test, because the time, temperature, and equipment are specified. The essential features of the equipment and details of the procedure are given in A.S.T.M. Designation: D271-44.:2. According to the specifications, the following features should be incorporated in the equipment used: 1. Oven must have uniform temperature in all parts. 2. Oven must be constructed with minimum of air space. 3. Oven must have means of changing the air two to four times per minute. 4. Air must be dried over sulfuric acid (sp. f-7. 1.84). The analytical procedures governing most of the nation's coal purchases are those given in A.S.T.M. Standards referred to above. These standards are general arid of such scope as to cover all ranks and types of coal. In cases where only the moisture is required, a faster method than the standard procedure is desired.

Jan 1, 1948

The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment: including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that arc recommended in this document, but all of the panic bars are characteristically of the "fire door" type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they arc required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in "Guidelines for the Design and Installation of Devices for Deenergization of Self-Propelled Electric Face Equipment/Automatic Emergency Brakes" by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel al the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By Khamis Y. Haramy

This U.S. Bureau of Mines report describes the use of Bureau-developed flat and cylindrical hydraulic borehole pressure cells. A brief description of the fabrication, installation, and pressurizing equipment is given and pressurizing procedures are discussed. Theories available on evaluation of data from the flat and cylindrical pressure cells and examples of data analysis and stress evaluation are also presented.

Jan 1, 1991

By G. L. Gates

The Bureau of Mines studied the scales formed in producing wells in the Wilmington field, California. The scales were primarily barium sulfate and resulted from the mixing of injected sea water and formation waters; there was excess sulfate in the injection water and the formation waters contained appreciable barium. After breakthrough, the produced brines were supersaturated with barium sulfate. Laboratory tests indicated that barium sulfate precipitated quickly When the supersaturated brines were agitated with crystals of barium sulfate and fairly rapidly when more sulfate solution was added. Precipitation occurred slowly on standing or under nonturbulent conditions. Both the apparent and equilibrium solubilities of barium sulfate in these brines were determined and compared with equilibrium solubilities in distilled water and sodium chloride solutions.

Jan 1, 1965

By Donald W. Ross

Petroleum oils of widely different grades have long been clarified or decolorized by contact with fuller's earths. More recently, so-called activated clays have also been used for this purpose. Still more recently ouch clays have been used in the form of nodules termed "catalytic pellets." Clays of varied appearance and from different localities possess the desired bleaching qualities, but evaluation of such clays, so useful to the oil industry, has not been simple. Previous methods of identification and evaluation have largely followed procedures of production methods and were not primarily based upon the fundamental properties of the clays. Thus) a false assumption has grown up that) bleaching clays probably have no common properties on which a-method of comparison can be based. Fuller's earths and activated clays have a large absorptive capacity for the color constituents of petroleum and its products decolorizing is accomplished by bringing the oil into intimate contact with the clay and later separating the decolorized oil from the clay with its load of absorbed coloring matter. Former practice in absorbing "color" was to use the clay as granules or In' powdered form. More recent practice is to use clay pellets that are more abrasion-resistant than the granules. The oil is either filtered through a bed of clay, percolation method, or agitated on contact with the clay, contact method. Viscous oils are decolorized at an elevated temperature, so that their viscosity is lowered to the point at which thorough contact with the clay is insured. Nonhumidifying, nonoxidizing gas, such as dry steam or dry nitrogen, is used to seal such hot oil masses from the atmosphere.

Jan 1, 1948

By Jerry A. Wichser

A series of linear programmed instruction modules was developed in the general subject areas of Blasting Technology & Explosives Safety & Electrical Training. The linear programs (modules) were developed in the form of tape-slide plus workbook materials, while the branching format evolved from the LTS teaching machine system from MIT, through several other teaching machines and micro-computers, finally settling on Radio Shack TRS-80 microcomputers, Models I & III. Initial validation figures indicate that essentially the same result, are attained from both methods (based on pre and post test scores), with the most noticeable difference being an approximately 25% savings in study time with the branching modules. In December 1980, the development of modules on High-Voltage Training, Trolley Wireman Training, and Compressed Gas Safety was added to the overall tasks of the contract.

Jan 1, 1984

By J. F. McCoy

As mining develops into deeper and hotter regions, the safety and health of miners require that the workspace be cooled. Toward this end, this program has successfully developed a high performance, low maintenance spray cooler of 5000 cfm nominal capacity. Further, a series of four 25,000 cfm, nominal capacity, spray coolers has been built and mine tested with satisfactory results. The smaller coolers have been patented and become commercialized with 50 units currently in service. The concept has been developed independently overseas with an unknown number of units in operation.

Jan 1, 1984

By William C. Cooley

Data on equipment and components which have been used in hydraulic mining experiments, tests, and operations were collected from the literature. Also data were obtained from U.S. manufacturers and suppliers of equipment which is potentially applicable and available in the U.S. for hydraulic mining. The data have been divided into 24 main categories (see the following page) and have been assembled on two-page data sheets which follow. Wherever possible, drawings or photographs are included immediately after each data sheet.

Jan 1, 1975

By Thomas M. Barczak

This U.S. Bureau of Mines report examines the causes and consequences of longwall face sloughage. Theoretical relationships were developed to evaluate mechanisms that produce slough age. From these relationships, contributory factors were identified for further analysis in field efforts. A survey identified 12 mine sites with sloughage problems, and these were investigated. From these studies, it was determined that the depth of cover and mining height are the two most significant factors causing sloughage on longwall faces. Coalbed friability and cleat orientation also were found to be significant factors in promoting sloughage. It was concluded that sloughage is primarily a problem in thicker seams or seams with friable coalbeds, and that the problem is more severe as the depth of cover increases. Sloughage also was found to increase as the rate of mining decreased. Observations indicated that face slough age can increase dust generation significantly on longwall faces. Current efforts to control dust generation from longwall sloughage are described.

Jan 1, 2010

By K. C. Dean

Fine-sized mineral wastes discarded by ore milling plants require stabilization to prevent air and water pollution. Stabilization has been attained by physical, chemical, vegetative, and combination procedures. Vegetative reclamation is preferred to physical and chemical stabilization but is diffi¬cult to achieve because the wastes are sterile, contain deleterious inorganic salts, and lack the essential nutrients and physical characteristics required for sustaining vegetative growth. Methods now have been developed for attain¬ing vegetative growth on all but excessively acidic, basic, or saline tailings at costs ranging from $120 to $650 per acre. The cost for stabilizing tail¬ings requiring more intensive treatment techniques may range upward to $1,750 per acre. This report summarizes procedures developed by the Bureau of Mines and industry for vegetating amenable tailings, lists costs for the various processes, and suggests procedures that may be applicable for stabilizing saline and pyrite-containing tailings. Ridged planting beds, drip irrigation, and deep-furrow planting techniques are suggested for stabilizing saline wastes. A combination of mill tailings and sewage sludge can be used for pro¬ducing synthetic soils, and layers of sewage sludge buried under a layer of tailings offer promise of inhibiting acid formation from oxidation of sulfides in mineral wastes.

Jan 1, 1974

By C. E. Jordan

The Bureau of Mines is conducting research into the pneumatic recovery of coarse mica and has used this method to produce mica concentrates that contain more than 90 percent mica. This research is being carried out pursuant to the Bureau's objective to develop technology that will help maintain an adequate supply of minerals and metals to meet national economic and strategic needs. Researchers used a Bureau-designed system of crushers, screens, and zig-zag air classifiers to concentrate coarse liberated mica particles from mica-bearing materials. This pneumatic system was used to concentrate four mica ores from Arizona, North Carolina, and South Dakota and three waste tailings from Alabama, Georgia, and South Dakota. Using these samples, it was demonstrated that plus 65-mesh size mica can be effectively recovered by the pneumatic method. Not only were the concentrates high in mica content; it was also demonstrated that this method can be used to recover up to 78 percent of the mica that was originally contained in the samples. Because it is a dry concentration method, the pneumatic beneficiation technique may be advantageous in areas where water resources are limited.

Jan 1, 1980

By Jennifer S. Riefenberg

The U.S. Bureau of Mines conducts basic and applied research related to predicting, eliminating, and/or controlling rock bursts in underground hard-rock mines and coal bumps in underground coal mines. An important element in this research is the development of a reliable and efficient microseismic source location technique. This report presents the results of a Bureau study to develop and evaluate a new algorithm to locate microseismic events based on the Simplex method, a powerful linear programming technique. The technique was tested on both field data and simulated data. Microseismic event source locations obtained with this new Simplex-based algorithm were shown to have less error than those locations obtained using a least squares method. It was concluded that the Simplex approach to source location of microseismic events can be used effectively in microseismic monitoring.

Jan 1, 1989

By Thomas Brunsing

The program was carried out to develop deep kerfing and core breaking techniques to be incorporated into the design of a field prototype hard rock mining machine. The field machine is designed to mine non-abrasive bedded deposits up to 20,000 psi in uniaxial compressive strength. The mining technique involves cutting approximately 2 ft deep parallel kerfs spaced 2 ft apart in either a horizontal or vertical direction and subsequently breaking out the cores so defined. The prototype machine is intended for demonstration of the technique in a quarry or equivalent field environment. The program was aimed at minimizing the required kerf width, obtaining reliable breaking within that kerf width and determining cutter blade requirements necessary to achieve a mining rate of 20 ft3/min. Full scale breaking experiments and 1/2 scale kerfing experiments were employed to evaluate the system. High strength concrete test specimens were used to simulate the rock being cut and broken. The test results indicate the kerf/break technique can achieve the desired mining rate by utilizing two 7 ft diam blades to cut 2 in. wide by 24 in. deep kerfs. A lateral load applied at the base of the kerf (base shear) was selected at the core breaking technique to be employed by the full-scale prototype machine.

Jan 1, 1983