Search Documents

By D. P. Lindroth

The thermal diffusivity above 298 K, up to 400 K and at pressures from ambient down to 10-10 torr was measured for the following six igneous rock types: tholeiitic basalt, obsidian, rhyolite, granodiorite, gabbro, and dunite. The thermal diffusivity data were obtained by the laser flash method. Extreme values range from a low of 5.3X10-3 cmF/sec for rhyolite at 383 K and 2X10-7 torr to a high of 13.4x10-3 crrf/sec for dunite at 298 K and 760 torr. Data are also included on a commercial fused silica, which was used as a standard.

Jan 1, 1974

By Richard L. Fowler

An automatic steering control system was designed, installed and tested on a coal mine shuttle car. The system utilizes sensors and associated signal processing electronics developed under a previous phase of this contract. The automatic steering system performs the routine guidance functions of turning corners and straight-through tramming. The shuttle car driver retains full authority of speed, braking, load and unload functions and at any time may exercise his option with manual override or steering. Steering information is generated from signals derived from the existing Lateral Guidance sensor subsystem, and all operational features of the previously developed open-loop system are retained. Above ground system tests were conducted in a simulated mine constructed of wood panel ribs. Results were in good agreement with prior hybrid computer simulations undertaken to validate the basic control system over a broad range of conditions and to select system parameter values. The automatic steering system was successfully demonstrated in the above ground simulated mine to USBM technical representatives. Designed to meet USBM permissibility requirements, the system is ready for a Phase II underground testing program. Testing in actual underground mine environment is expected to provide additional data regarding recommended performance improvements and implementation techniques.

Jan 1, 1975

By Anderson Dana

THIS PAPER describing methods and costs of mining and preparing gravel and sand for market at the Port Jefferson plant of the Seaboard Sand and Gravel Corporation, is one of a series of articles on gravel and sand mining, prepared for and published by the U. S. Bureau of Mines, which is designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total costs, It is recognized that publication of total costs might in many instances cause embarrassment to individual producers, as well as to the industry as a whole. On the other hand, operating costs are essential to the technical [ ]

Jan 1, 1932

By George A. Savanick

This paper reviews advances in the art of borehole (slurry) mining made by the Bureau of Mines from 1974 to 1980. The design of a proto-type borehole-mining tool (BMT) developed by the Bureau of Mines is pre-sented along with production data, reclamation data, and an application of the BMT to the mining of coal, uraniferous sandstone, oil sands, and phosphate ore. The BMT was first used near Wilkeson, WA, where steeply pitching metallurgical coal was mined at 8 st/h from a depth of 25 to 75 ft. Next, 940 st of uraniferous sandstone was mined at 8 st/h from a depth of 75 to 100 ft in Natrona County, WY. One thousand short tons of oil sands was mined in Kern County, CA, at the rate of 14 st/h from a depth of 110 to 150 ft in 1979. Most recently, 1,700 st of phosphate ore was produced at 25 st/h from deep (230-to 250-ft) deposits in St. Johns County, FL. Progressive improvements were made in the borehole mining technique. These include the use of the hydrostatic head of a water-filled borehole for roof support, and the development of methods to survey and backfill mined-out cavities.

Jan 1, 1987

By H. J. Heinen

This Bureau of Mines report reviews the recent developments in the heap leaching of gold ores with dilute cyanide solutions and the recovery of gold and associated silver from the pregnant effluents by a carbon adsorption-desorption method. Mineralogical considerations, experimental work, field studies, and commercial operations are described. Also presented are recent process advances developed by the Bureau, including the application of (1) alcohol additives to the conventional hot alkaline cyanide strip solution to enhance gold desorption from precious metal-laden activated carbon, and (2) Na2S precipitation of the silver from geld-silver cyanide solutions as a means of reducing the inventory of carbon required for precious-metal adsorption from heap leach effluents and for the production of low-silver bullion from activated carbon stripping solutions.

Jan 1, 1978

By Derek Ellis

Volume II of this two-part series on Submarine Tailings Disposal (STD) as a tailings management option for coastal and island mines contains descriptions of lesser known case histories. The Misima gold mine (Papua New Guinea) and the Black Angel lead-zinc mine (Greenland) are described in some detail as the best documented cases. Atlas copper mine (The Philippines) is less fully described due to relative lack of documentation. The Misima and Atlas STD systems are working to their design criteria. At Black Angel the system adopted did not prevent contamination for a number of reasons, which are now understood. Two cases are described where STD is being developed. They are the Cayeli Bakir copper mine Turkey), and the Toquepala and Cuajone mines (Peru). There is excellent documentation available for both cases. Three case histories are described where tailings have reached the sea either through beach or river discharge. In one case the STD option has been explored (Marcopper Mine, The Philippines). In the others we explore in hindsight whether STD might have been a viable alternative using the Screening Criteria that this Volume develops - see below. The mines are Bougainville Copper Mine in Papua New Guinea, and Jordan River Mine (Canada). There is potential for STD at all three sites. Finally, the Volume presents Screening Criteria for appraising STD, based on the experience in design, operation and environmental impact reviewed in the case histories.

Jan 1, 1994

By B. W. Gandrud

This is the third report published by the Bureau of Mines concerning the washability of Black Creek coal. Both of the former reports.5/6/ dealt with the Black Creek coal at the Bradford mine, Dixiana, Ala., near the northeastern extremity of the Warrior field, whereas the present report is based on float-and-sink tests of coal from what is presumably the Black Creek bed near the southern extremity of the field. Although the Yolande Coal & Coke Co., owners of the property at Yolande No. 6 slope, consider this opening to be on the Black Creek bed, the authors do not feel that there is as yet positive proof that this correlation is correct. There has been little or no development of the Black Creek bed in the Yolande Basin in the past, and a positive identification of the bed at Yolande No. 6 will have to await further exploration and development. The Yolande No. 6 is an exploration slope 3/4 mile north of Rockcastle, Ala. The slope is approximately 400 feet from top to bottom on a dip of 180. As far as the authors can ascertain, coal has never been produced commercially from the Black Creek bed in the southwestern part of the Warrior field. Exploration work in the past has indicated that the Black Creek coal in this area is extremely friable and high in sulfur. Extreme friability would naturally discourage its use as a domestic and railroad fuel, and high sulfur content would be a disasvantage in its use for coking coal. The present study of this coal has been made with particular reference to sulfur elimination on the assumption that it would make a good coking coal provided enough of the sulfur could be eliminated by washing.

Jan 1, 1939

By Robert W. Metcalf

Corundum, natural alumina, or aluminum oxide (A1203) is the hardest mineral known except diamond. Theoretical composition is Al 52.9 percent and 0 17.1 percent, but it always contains small quantities of impurities, chiefly silica, iron, and lime. The melting point of corundum is above 1950° C., and it is insoluble in the strongest acids. Its hardness (9 on the Mohs scale) varies slightly according to purity, and its specific Gravity ranges from 3.95 to 4.10, 4 being a fair average. The index of refraction is 1.760 to 1.768 and its streak is white. Luster is adamantine to Vitreous, come specimens pearly, and color varies widely from white, gray, pink, and blue to black, brown, or bronze. Gem varieties are transparent or translucent, and of more brilliant coloring - red, blue, yellow, purple, or green. Corundum occurs in opaque massive or block structure with parting planes little developed or only roughly delineated and in granular form as minute crystals or small, irregular grains interspersed throughout the contact zones of schists and gneisses.

Jan 1, 1944

By Jesse L. Hoyer

A Bureau of Mines turbomill was evaluated for use in the production of high-purity, ultrafine x-Sic powders suitable for advanced ceramics that could substitute for high-temperature alloys containing critical materials such as chromium, cobalt, and nickel. The effect of milling param-eters, such as type of dispersant, temperature, pH, and gas environment, on the milling of x-SiC was studied. The addition of dispersants improved the grindability of x-SiC. Of the six dispersants studied, the best results were obtained with Mara-sperse N-22. Grinding efficiency was also increased when the x-SiC was milled in a basic slurry and at elevated temperature. Gas environments did not appear to affect grinding of x-SiC. Optimum grinding efficiency was obtained at 50° C in a slurry at pH 9.5 with Marasperse N-22 as the dispersant. Under these conditions, minus 100-plus 200-mesh x-SiC was ground to 80 pct less than 1 um in 4 h.

Jan 1, 1987

By Louis Schaffer

The objectives of the research were to determine whether a model health and safety program could be defined in terms which would enable its application to mines of all types, and, if such a model program could be defined, to determine through evaluations in two mining companies whether it would achieve measurable improvements. Volume 1 describes the model, how it was applied in the field and how it was evaluated. This, Volume 2, describes the literature and field research that preceded the model definition.

Jan 1, 1983

By M. J. Ferrante

Laboratory-scale tests were undertaken to examine several electrolytes for possible use in separating nickel and cobalt from products being prepared at Nicaro, Cuba. The most extensive work was done with nickel sulfate-ammonium fluoride, ammonium fluoride, ammonium sulfate, and nickel sulfate-boric acid electrolytes. All four electrolytes exhibited some selectivity for dissolving nickel carbonate from Nicaro basic carbonate used for regeneration. The nickel sulfate-ammonium fluoride electrolyte exhibited less selectivity for dissolving nickel carbonate from Nicaro basic carbonate than it did from synthetic mixtures. Ammonium fluoride leaching experiments showed that a low concentration and high temperature gave a good nickel extraction with C. P. reagents; however, this was not confirmed in tests using Nicaro basic carbonate. Electrolytic tests employing ammonium fluoride leach liquors gave no further separation, since approximately 90 percent of the cobalt was deposited at the cathode with the nickel.

Jan 1, 1958

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in the' production of crushed stone. These studies, made at quarries scattered over the eastern and southeastern parts of the United States, have not been completed, but to make results available to the industry as early as possible it was decided to publish summaries of the studies made to January 1, 1939, as a series of progress reports. The first of these reports dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The present circular discusses analyses of the time Studies of the haulage systems at the same quarries. OBJECT OF STUDY The pressure of business problems frequently requires the entire atten¬tion of quarry management and in consequence internal plant economies often are neglected, Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that similar studies of many plants by impartial engineers would disclose possibilities for cost reduction or greater efficiency in internal plant processes.

Jan 1, 1939

By Nicholas Kyriazi, John P. Shubilla

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory, has undertaken a study to determine how well self-contained self-rescuers (SCSRs), deployed in accordance with Federal regulations (30 CFR 75.1714), hold up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSRs in the sixth phase of testing from mid-1996 to early 1998. The SCSRs were tested on human subjects and on a breathing and metabolic simulator. These results indicate that most of the apparatus, if they pass their inspection criteria, perform satisfactorily. However, the deployed CSE SR-100s exhibited significantly higher inhaled CO2 levels than new units, as in the previous phase. This will cause higher ventilation rates in most users, which will, in turn, result in higher breathing pressures, possibly causing users to prematurely remove the apparatus. CSE Corp. has developed a noise test that can identify apparatus suffering from chemical-bed degradation causing the early CO2 breakthrough. This test was added to the inspection criteria for the SR-100. In addition, several of the MSA Portal-Packs that passed their inspection criteria were found to have KO2 dust in their mouthpieces. Further investigations by NIOSH and the Mine Safety and Health Administration confirmed these findings, which resulted in the decertification of the apparatus and their removal from service.

Jan 1, 2000

By B. R. Klahold

Each year hundreds of mineral specimens and numerous inquiries regarding tests and analyses of minerals and related inorganic substances are received by the Bureau of Mines. In response to this demand, in years past Information Circulars were published containing a list of laboratories. This paper is a revised version of Information Circular 7523, The listing has been changed from a regional basis to one of States arranged alphabetically and grouped by cities, again alphabetically, with Alaska and Canada listed at the end. All the services given at these laboratories are listed on one page for convenience and brevity. This list is compiled as a public service, and none of the laboratories listed herein are recommended over any other nor can the Bureau of Mines vouch for their results.

Jan 1, 1954

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in the production of crushed stone. These studies, made at quarries scattered over the eastern and southeastern parts of the United States, have not been completed, but to make results available to thee industry as early as possible it was decided to publish summaries of the studies made to January 1, 1939, as a series of progress reports. The first of these reports dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The present circular discusses analyses of the time Studies of the haulage systems at the same quarries. OBJECT OF STUDY The pressure of business problems frequently requires the entire attention of quarry management and in consequence internal plant economies often are neglected, Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that similar studies of many plants by impartial engineers -would disclose possibilities for cost reduction or greater efficiency in internal plant processes.

Jan 1, 1939

By John R. Bartels

This Bureau of Mines report describes the development of a preliminary design for a novel, protected, cab-shuttle car for use in working seam heights down to 40 in. Because of the severe restrictions imposed by low-coal operation, Mine Safety and Health Administration (MSHA) regulations only require canopy protection on shuttle cars operating in seam heights of 42 in or greater. MSHA routinely grants variances for canopy use in seams 48 in high or less. The design was generated by giving the operator needs equal priority as related to machine performance parameters. Cab-shuttle car concepts that led to the recommended design are described, along with criteria and testing used to evaluate their potential effectiveness.

Jan 1, 1988

By I. Liebman

A Bureau of Mines study is in progress to determine the effectiveness of passive water barriers in suppressing coal-dust explosions. A 2.9-ft3-capacity water-filled plastic tub was found effective in suppressing dust explosions propagating at speeds of 250 to over 1,000 ft/sec. Work directed at determining the limitations of water barriers showed that the passive water barrier technique is also feasible for the suppression of weak dust explosions propagating at speeds of 100 to 250 ft/sec. For relatively slow accelerating flames, dynamic wind forces appear to be the important quantity governing fragmentation of the plastic tub and subsequent water release and dispersion, whereas dynamic impulse appears to be the significant quantity for rapidly accelerating flames. The acoustic approximation (relation between static pressure and flame or wind speed) is shown to be valid in a long single mine entry. This relationship appears to be useful in predicting the regions within a long single entry where passive water barriers are effective in quenching a dust explosion.

Jan 1, 1974

By J. C. Edwards, C. C. Hwang

In ventilated tunnel fires, smoke and hot combustion products may form a layer near the ceiling and flow in the direction opposite to the ventilation stream. The existence of this reverse stratified flow has an important bearing on fire fighting and evacuation of underground mine roadways, tunnels and building corridors. In the present study, conducted by the National Institute for Occupational Safety and Health, a CFD program (fire dynamics simulator) based on large eddy simulations (LES) is used to model floor-level fires in a ventilated tunnel. Specifically, the critical ventilation velocity that is just sufficient to prevent the formation of a reverse stratified layer is simulated for two tunnels of different size. The computer code is verified by checking the computed velocity profile against experimental measurements. The CFD results show the leveling-off of the critical ventilation velocity as the heat release rate surpasses a certain value. At this critical ventilation, the ceiling temperature above the fire reaches a maximum for both tunnels. The velocity leveling-off can be explained from this observation. An extended correlation of Newman (Combust. Flame 57 (1984) 33) is applied to the temperature profiles obtained by CFD. At the critical ventilation, temperature stratification exists downstream from the fire. The computed critical ventilation velocity shows fair agreement with available experimental data taken from both horizontal and inclined fire tunnels. The CFD simulations indicate that the Froude modeling is an approximation for tunnel fires. The Froude-scaling law does not apply to two geometrically similar fire tunnels. The CFD results are compared with two simple theories of critical ventilation by Kennedy et al. (ASHRAE Trans. Res. 102(2) (1996) 40) and Kunsch

By Annie G. Smelley

As a part of research conducted in its mission to effect pollution abatement, the Bureau of Mines, U.S. Department of the Interior, is developing a dewatering technique that allows for disposal of clay wastes, for reuse of water now lost with clays, and for reclamation of mined land. The technique utilizes a high-molecular-weight nonionic polyethylene oxide polymer (PEO) that has the ability to flocculate and dewater materials containing clay wastes. In laboratory experiments, coal-clay waste, potash-clay brine slurry, phosphatic clay waste, uranium tailings, and talc tailings were successfully consolidated. Coal-clay was te was consolidated from 3-. 6 to 57 percent; potash-clay brine slurry was consolidated from 3.8 to 35 percent; phosphatic clay waste from 15.6 to 49 percent; uranium tailings from 15.4 to 67 percent; tailings from talc production from 9.7 to 53 percent; and an acidic Ti02 slurr slurry from 1.68 to 30 percent.

Jan 1, 1980

By V. F. Swanson

As part of the Bureau of Mines titanium resources examination program, samples of altered rock (saprolite) and unaltered rock from the Roseland anorthosite near Roseland, Nelson County, Va., were tested for amenability to beneficiation by flotation. A flotation technique was developed to produce bulk concentrates of ilmenite, rutile, sphene, and leucoxene. It was necessary to first float apatite using oleic acid as the collector, in an alkaline pulp with dextrine as a titanium mineral depressant. The titanium minerals could then be floated from the apatite tailing, using fluosilicic acid to depress the remaining apatite, morin to depress ferromagnesian minerals (when present), and oleic acid as the collector. A bulk titanium mineral concentrate, analyzing 66.0 percent Ti02 and 0.08 percent P205, was obtained from a sample of the unaltered rock which contained 5.45 percent TiO2 and 2.81 percent P205. Overall recovery in the concentrate was 47.1 percent of the total TiO2 in the ore. About 55 to 65 percent of the saprolite sample was clay and was removed by attrition scrubbing and decantation. The apatite prefloat procedure was applied to the saprolite sands; subsequent titanium mine: 1 flotation recovered 72.2 percent of the Ti02 in a bulk concentrate containing 65.1 percent TiO2 and 0.20 percent P205.

Jan 1, 1962