Search Documents

By George S. Scott

The Bureau of Mines conducted ignition, flammability, and decomposition experiments on gas mixtures containing ethylene to determine its flammability characteristics at elevated pressures and ambient temperatures. Pure ethylene was found to propagate a decomposition reaction at 1,000 psig and ambient temperatures when ignited with 1 gram or more of guncotton in a 2-inch-id bomb. The decomposition products were primarily carbon, methane, and hydrogen.

Jan 1, 1965

By George J. Conroy

Types and causes of short-circuit and open-circuit faults in mine portable trailing cables are discussed, and techniques for locating these faults are described. Time domain reflectometers (TDR) , tone generator, infrared sensing, and high voltage methods are covered. The paper summarizes Bureau of Mines research, including development of a ~DR/tone generator sender with auxiliary probe.

Jan 1, 1975

By W. L. Cornell

The Missouri Pb ores are the only domestic Co resource being mined and processed for other metals; therefore, they present a viable short-term opportunity for Co production. Lead, zinc, and copper concentrates are produced from the ore. The Cu concentrate can contain up to 30 pct Co and the Pb concentrate up to 15 pct Co. Since Co is detrimental to the processing of the Zn concentrate; the remainder of the Co is rejected to the tailings. The tailings can contain as much as 50 pet Co originally present in the mined ore. Researchers at the U.S. Bureau of Mines have successfully tested on a continuous basis a process that recovers a bulk sulfide concentrate from mill tailings. The concentrate contains up to one-half of the Co and from 50 to 90 pct of the Pb, Zn, and Cu. Concentrate weight represents 10 pet or less of the total tailings.

Jan 1, 1989

To increase awareness of float coal dust explosion hazards in the mining industry.

Jan 4, 2006

By William H. Schiffbauer

This report details a microcomputer-based control and monitoring network that was developed in-house by the U.S. Bureau of Mines and installed on a continuous mining machine. The network consists of microcomputers that are connected together via a single twisted-pair cable. Each microcomputer was developed to provide a particular function in the control process. Machine-mounted microcomputers, in conjunction with the appropriate sensors, provide closed-loop control of the machine, navigation, and environmental monitoring. Off-the-machine microcomputers provide remote control of the machine, sensor status, and a connection to the network so that external computers can access network data and control the continuous mining machine. Because of the network's generic structure, it can be installed on most mining machines.

Jan 1, 1993

Reduce rockfall fatalities and injuries by using innovative blasting practices to reduce damage to the rock at the excavation limits with little or no increase in cost. The Problem Falls of highwall have been a leading cause of fatalities, injuries, and equipment damage in the surface mining industry. Although the number of highwall falls is not great, when such an incident does occur it is about 14 times more likely to be fatal or result in severe injury and damage to equipment than other types of surface mine accidents. Overbreak or damage to the rock from poor or improper blasting practices is a major factor contributing to rock falls. Presplitting or cushion blasting is the technique most often recommended for improved wall control. This type of blasting however, adds to drilling and blasting costs and is not universally accepted by the industry. Air gap presplitting techniques, also called air decks, are currently being used in some mines as a less costly alternative to conventional presplitting. Approach Blasting can cause highwall damage, but proper blasting techniques have been shown to reduce the magnitude of rockfall problems. In preventing rock falls, it is important to maintain the natural strength of the rock structure to the greatest extent possible. Improved blasting practices have three main advantages: 1) they are preventive rather than corrective in nature; 2) they are cost effective; and 3) they have a very low impact on the mining operation when properly implemented. New ways of evaluating highwall integrity, such as seismic refraction tomography, were investigated.

Jan 1, 1991

By Ed Mchugh

NIOSH researchers collected basic data from two blast rounds at the SSX-Steer Mine as a component of a larger study on controlled blasting, the goal of which is to reduce injuries from falling rocks in underground mines. Drilling and blasting procedures at the mine were observed. Rock mass property data were collected, a program of seismic monitoring and analysis was conducted, and 3-D laser survey scans of the workings before and after each blast were performed. The geologic data showed that the rock mass quality was characterized as poor to very poor. It was essentially uniform within the panels examined. The recorded seismic data indicated that fill material acted as an effective damper to seismic energy. The pre- and post-blast laser scans showed both over-break and under-break conditions, highlighting the problems associated with blasting a weak rock mass. By comparing the achieved results to the intended design, potential improvements in the drilling and blasting practices can be identified. Comparison of these data with similar data from other mines will help define how various combinations of rock and fill behave during blasting. Through studies such as these, data collection procedures and analysis techniques can be refined. An ultimate goal is to develop blast procedures tied to rock mass characteristics that can minimize damage to rock in the perimeter of the opening, limiting the amount of loose rock and improving the safety of miners.

Jan 1, 2007

Reduce spillage hazards and contamination when adding hydraulic nil to mining machine reservoirs. Approach An easily transported module, that delivers hydraulic oil directly into mining machines, was built and tested. How It Works The Hydraulic Oil Delivery Module is carried, from the oil storage area to the equipment needing oil, in the bucket of a scoop or other utility vehicle. Oil is pumped into the module reservoir from storage, or out of the module reservoir into the machine being serviced, through a long hydraulic hose. During long-term testing, the 115 foot long delivery hose made it possible to replenish the hydraulic oil in mining machines at the face with only limited interruption to the mining operation. (Figure 1 shows one! version of the module.) The compact Hydraulic, Oil Delivery Module consists of: an oil reservoir: a pump driven by a hydraulic motor; two high pressure, low volume oil lines, filters; and a low pressure, larger capacity delivery hose equipped with quick-connect-couplers. The high pressure oil lines are connected to the scoop's hydraulic power takeoff, which supplies the power to pump oil in or out of the module reservoir.

Jan 1, 1977

By Stuart R. Zimmerley, John Gross

"In the study of ball-mill grinding at the Intermountain Experiment Station of the United States Bureau of Mines at Salt Lake City, Utah, it was desirable to measure the work input to a ball mill at the mill itself so that consideration of motor efficiency and transmission losses would be eliminated.The device adopted is essentially that used by Prof. H. E. T. Haultain4 in measuring work input to rolls. The mechanism was changed only so as to adapt it to a ball mill.Figure 1 is a diagrammatic sketch of the apparatus.The pulley which rotates the mill is loose on the mill shaft and is equipped with ball bearings. This pulley is connected by means of three tangential springs to the driving plate, which is solid on the mill shaft. Power applied to the loose pulley is transmitted to the driving plate, and hence to the mill, by the three springs; the greater the resistance of the mill, the greater the spring extension. The extension of the springs is transmitted by the steel extension tape to the differential integrating meter.The integrating meter is operated by two friction wheels in contact with the integrator disk which revolves at a definite ratio of speed to that of the mill. The friction wheels are held in contact with the disk by the spring suspension of the integrator and are connected to a differential gear cage, the revolutions of which are recorded on a counter such as is used in gas meters. Due to the differential gears the c e is stationary when the two friction wheels revolve at the same speed in opposite directions; this condition exists when the integrator is centered on the disk and corresponds to no load or to a zero spring extension. As the lead is applied, the springs extend and move the integrator from the center or zero point, resulting in a difference of speed between the two friction wheels. Due to the revolution of the differential cage this change in. speed is transmitted to the counter. The integrator and extension tape system is kept taut by means of a light spring attached to the integrator, the spring having just enough tension to assure that the integrator returns to zero when the load becomes zero."

Feb 1, 1931

By N. E. Hanna

To be approved for use in underground coal mines in the United States, explosives and blasting devices must pass certain safety tests prescribed by the Federal Bureau of Mines. These tests are described in Schedule 1-G4/ (explosives) and Schedule 26A5/ (blasting devices). An explosive or blasting device that passes the appropriate tests is placed on the active permissible list. As this list is subject to continuous revision, it has been the practice of the Bureau of Mines to publish periodically the names of explosives and blasting devices that have been added to the active list, as well as those that have been transferred to the inactive list; changes in brand names also are reported. The present circular gives all explosives and blasting devices on the active permissible list as of December 31, 1957, and shows all changes, additions, and transfers in that list between December 31, 1951,6/ and December 31, 1957.

Jan 1, 1958

By Maurice Deul

A special short-term research project was initiated to develop plant design parameters for treating mine waters to yield an effluent acceptable for discharge into streams and a sludge amenable to effective and economic disposal. Neutralization was investigated to provide simple and direct treatment of ferruginous acid waters using lime; coarse limestone, and limestone followed by lime. Limestone treatment was accomplished using a small cement mixer as a simple reactor to provide abrasive agitation of limestone and mine water. Results from tests with nine mine waters encompassing a wide range of iron and acid concentrations showed that coarse limestone, one of the cheapest neutralizing agents known, is potentially useful for treating mine water discharges. However, process variables must be defined more completely before the practical applications and limitations of the process can be fully established. In all the tests a pH of >7.2 was obtained ultimately with limestone. Reaction time to reduce the iron content below 7 ppm in the water was dependent on the original ferrous iron concentration. For waters with high ferrous iron content, treatment with limestone followed by lime rapidly produced an acceptable treated water, Sludges with good settling and handling characteristics resulted when limestone was used for neutralization either alone or with subsequent treatment. Reaction rates are expressed graphically as pH change and iron depletion curves; characteristic solids settling curves are shown. The temperature dependency of ferrous iron oxidation was verified.

Jan 1, 1967

By J. H. Jacobs

The first authorization, in November 1940, was for a plant of only several hundred pounds capacity at Boulder City, Nev. Improvements in the process and subsequent additions to some sections have enabled the plant to produce more than 2,000 pounds of manganese per day for substantial periods. By the time pilot-plant operations were suspended in June 1945, over 1,500,000 pounds of metal had been produced. The future of electrolytic manganese production obviously depends not only on satisfactory development of methods but on availability of raw material and demonstration of valuable uses. Investigations of manganese-ore deposits in this country, made since 1938 by the Bureau of Mines, have revealed large amounts of ore suitable for making electrolytic manganese. At first the pilot plant was operated on ore from the Three Kids mine near Las Vegas, Nev. After practical features of the process had been worked out, other ores from throughout the United States were tested in the pilot plant. The purpose of this paper is to compare the results obtained on the following ores: Three Kids; Ladd mine, Tracy, Calif.; Chamberlain, S. Dak., nodules; and ore from Metals Reserve stockpiles at Deming, N. Mex.; Cushman, Ark.; and Philipsburg, Mont.

Dec 1, 1947

By Paul W. Jeran

This Bureau of Mines report has been prepared to provide a means whereby mineworkers without specific geologic training can recognize and record the existence of potentially hazardous geologic features encountered in coal mines. Each geologic feature described in this report has been implicated in roof failure. Through the recording of the observations of mineworkers, based on this report, a geologic map of mine workings and the associated ground control problems can be compiled. From such maps, the trends of changes and features can be determined and projected ahead of mining. The face crew can be alerted to a potential problem and what to look for as the face is advanced.

Jan 1, 1983

By R. D. Leitch

Tests have recently been conducted by the Bureau of wines on the ignition hazard of exposing heated filaments of electric mine lam bulbs in an explosive mixture of methane and air. This investigation was undertaken in order to settle a question that had arisen in connection with the safety of miners? electric lamps. For several years, in view of former studies made by the Bureau and reported in Bulletin 524, the fact that the heated filaments of even low voltage, lour candlepower bulbs constitute a danger was generally accepted by the Bureau's engineers. These early tests, as well as subsequent tests, were conducted with Pittsburgh natural was as the testing medium.

Jan 1, 1925

By C. T. Baroch

This report summarizes cost data accumulated during 15 months of sustained operation of the Bureau of Mines Boulder City (Nev.) titanium plant, which had a capacity of about 1,350 pounds of titanium sponge per day. The plant was constructed during the 1952 fiscal year with funds supplied by the Ordnance Corps, Department of the Army. Its original purpose was to engage in process development work as a continuing phase of the Bureau of Mines policy to seek improvements in producing titanium metal. In early 1953 the Defense Materials Procurement Agency contracted with the Bureau of Mines for producing approximately one-half million pounds of usable ductile titanium sponge. Production began in May 1953, ended in September 1954, and yielded 492,503 pounds of acceptable metal. Operating costs covering this period of operation, with suggested depreciation and administrative costs, are given, as well as outlines of building and equipment capital costs. In addition, miscellaneous economic considerations are discussed, including labor and operating-time schedules.

Jan 1, 1956

By W. W. Adams

"Although rock-dust is an effective and generally recognized preventive of wide-spread explosions in bituminous-coal mines and although in explosions many lives have been saved by its use that almost certainly would have been lost otherwise, yet more than two thirds of the yearly production of bituminous coal from underground mines in the United States is still being obtained from mines that do not use rock-dust, and more than two thirds of all men that work underground in bituminous mines are employed in nonrock-dusted mines. These facts are revealed by a statistical survey of all mines in the United States that were in operation during 1930, 1931, and 1932. The survey was conducted by the Demographical Division of the Health and Safety Branch of the United States Bureau of Mines and was based upon reports from operating companies received in connection with the Bureau's annual statistical surveys of accidents in the mining industry.In 1932, the latest year for which complete figures are available, rock-dust was used, to some extent at least, in 393 bituminous-coal mines whose total production of coal during the year was 83,632,327 tons, or 30.6 percent of the entire output of bituminous coal from all mines in the United States not including opencut mines. The number of men employed underground at mines that used rock-dust was 25.7 percent of the total number employed underground at all bituminous mines, and the number of man-hours worked at these mines was 27.1 percent of the total number of man-hours worked underground at all bituminous mines during the year."

Nov 1, 1934

By James H. Cobbs

The purpose of this study is to investigate the application of boring equipment to the production of anthracite coal from steeply pitching beds. Both raise boring and augering equipment were considered. Previous studies (11) have indicated that boring equipment may have definite applications to the development of steeply pitching anthracite beds. This investigation was to carry forward previous work to determine the possible application of the two different types of equipment being considered. Previous conclusions have been substantiated by the results of this study.

Jan 1, 1975

By Richard G. Burdick

The Bureau of Mines conducted this research to determine the feasibility of using soil redox measurements, a relatively new method in mining geophysics, to locate or define a variety of conditions that are hazardous or otherwise of interest to the mining industry. The method was used in three widely separated areas in an attempt to de- fine subsurface concentrations of methane, the edges of coal-burn areas, and a hydrothermal vein set. Both a description of the method used and test cases are given in this report.

Jan 1, 1982

By A. B. Hooker

Investigations at the Pittsburgh Experiment Station of the Bureau of Mines have shown that satisfactory operation of a flame safety lamp depends not only upon proper design and assembly of the lamp but also upon the kind

Jan 1, 1945

Reduce worker exposure to respirable dust without interfering with bag-filling operations. Approach A dust control hood was developed which contains and captures dust close to its source and prevents it from entering the bag-filling operator's work place. How It Works A sheet metal hood is placed around the nozzle of the bag filling machine. The hood is connected through ducts to the plant exhaust ventilation system. Air pulled into the front of the hood and around the sides of the bag picks up dust generated inside the hood, and carries it to the dust collector. The size of the hood can be adapted to fit most fluidized valve-type bag-filling machines. The height of the hood depends on the bulk density of the product and weight of the bags being filled. The 14-inch-width of the hood allows it to be used on multi-nozzle baging machines spaced 16 inches on center. Only 2/3 of the bag is actually within the hood, and this allows easy operator access for placing the bags on the nozzle.

Jan 1, 1978