Search Documents

By T. M. Ruff

The U.S. Bureau of Mines has developed a portable, inexpensive teleoperation system for mobile hard-rock mining equipment. The system was tested on a compact loader-trammer in a simulated stope. The teleoperation system includes radio remote control and computer-assisted navigation. A recent enhancement includes video cameras mounted on the machine to provide visual information to the operator. This system allows the operator to remain in a safe location while operating the machine from a distance, thus increasing both operator safety and mining productivity.

Jan 1, 2010

By Kenneth M. Earl

In its investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling at the New Galena Deposit in an endeavor to find an additional source of supply of lead. In Bucks County, lead and zinc minerals have been found in shales over a largo area west and northwest of Doylestown. Considerable mining has been done in the vicinity of New Galena on the North Branch of Noshaminy Creek, 3 miles northwest of Doylestown. It has not been possible to obtain a satisfactory history of the New Galena mine, as there is much disagreement in statements. Most of the mining was done in open pits. Two shafts were sunk to shallow depth; one of these became part of the main pit' which is 256 foot long, 50 to 75 feet wide, and 20 to 44 feet deep. Small pits 8 to 10 foot square wore sunk on the ore zone, which extends some 1450 feet to the southwest. The rock containing the minerals is either black or gray shale. The gray material closely resembles limestone. The following minerals have been reported from the mine: quartz, ankerite, calcite, galena, sphalerite, pyrite, chalcopyrite, and bornite. Some of the galena has yielded 10 to 15 ounces of silver and 10 cents in gold per ton. The average grade of the ore as mined is not known. To investigate the downward extension of the ore shoot, the Bureau drilled two holes aggregating 373.9 feet, No additional ore was developed by this work.

Jan 1, 1950

By Liming Yuan

A computational fluid dynamics (CFD) study was conducted to model effects of coal properties on the potential for spontaneous heating in longwall gob (mined out) areas. A two longwall panel district using a bleeder ventilation system was simulated. The permeability and porosity profiles for the longwall gob were generated from a geotechnical model and were used as inputs for the three dimensional CFD modeling. The spontaneous heating is modeled as the low temperature oxidation of coal in the gob using kinetic data obtained from previous laboratory scale spontaneous combustion studies. Heat generated from coal oxidation is dissipated by convection and conduction, while oxygen and oxidation products are transported by convection and diffusion. Unsteady state simulations were conducted for three different US coals and simulation results were compared with some available test results. The effects of coal surface area and heat of reaction on the spontaneous heating process were also examined.

Jan 1, 2008

By A. F. Colombo, D. W. Frommer

Bench- scale tests were made to determine the applicability of flotation as a means of upgrading finished and semifinished magnetic concentrates prepared from reductively roasted iron ores . Both anionic and cationic flotation methods were used to remove siliceous gangue from the magnetic concentrates and produce upgraded products . Seven magnetic concentrates , containing from 6.7 to 13.7 percent SiO2 , were improved by the flotation treatment , yielding final concentrates containing less than 6.0 percent Si02 . Cationic flotation methods were studied on four of the seven samples ; of this group only one sample yielded better results by cationic flotation than by the anionic method .

Jan 1, 1964

By F. E. Block, T. T. Campbell, D. Z. Hobbs

Several methods were investigated for the preparation of high- purity elemental boron in an attempt to develop a feasible process for producing boron on a large scale . In the work described in this report , the metal was prepared by metering boron trichloride gas into a crucible containing molten metal reductants . It was necessary to remove reaction byproducts by acid and aqueous leaching . Magnesium and sodium were tested as reductants , but best results were achieved using lithium or zinc as reductants . Contaminants originating from the materials of construction were the chief impurities in boron made by this method . Impurities ranged from 0.5 to 5.0 percent . Impure boron ( 85 to 90 percent ) was also prepared by the magnesium reduction of boron trioxide in a thermite - type reaction . This product contained magnesium as the chief contaminant . Impure boron made in this way could be upgraded by fusing with potassium fluoborate or potassium acid fluoride . After acid leaching the fusion cake , a product containing 95 to 97 percent boron was obtained . Analytical techniques for accurate determination of impurities in elemental boron are a major problem , requiring solution before a valid comparison can be made of the quality of boron prepared by these various methods .

Jan 1, 1964

By John B. Gayle

The suitability of fluid petroleum coke as a blending agent for producing metallurgical coke has been investigated using the Tuscaloosa and sole-heated experimental ovens. From the results of tests with three representative blends, it has been fond that additions of fluid petroleum coke effect the following changes: (1) Increase in size, resistance to shatter, and apparent specific gravity of cokes produced; (2) little or no change in coke hardness and stability or in the amount of breeze formed; (3) increased charge density; (4) modification of expansion characteristics of blends charged; and (5) decreased ash and increased sulfur contents of blends charged and cokes produced. Substitution of a calcined sample of fluid coke of greatly reduced sulfur content resulted in a coke of inferior physical properties. This effect indicates that additions of the calcined product should probably be limited and that other methods for producing a low sulfur fluid coke should be considered.

Jan 1, 1956

By P. C. Good

This Bureau of Mines report describes the preparation of phosphoric acid directly from phosphate ore, without prior beneficiation, in a small-scale, continuous process research unit, as part of an effort to improve minerals and metals recovery from domestic resources while minimizing environmental effects. Three phosphate-matrix samples, ranging in grade from 18.2 pct P20S5to 11.9 pct P205, were dry-fed at a rate of 1.82 kg/hr (4 lb/hr) to a continuous-circuit, 12-liter, single-tank digester to yield phosphoric acid and byproduct gypsum filter cake. Comparison with earlier data shows that a significantly improved filtration rate was attained in a single-tank reactor compared with that attained in a five-tank reactor train processing the same ore. Iron and aluminum impurities in the product phosphoric acid averaged about 60 pct higher than amounts reported in commercially prepared, concentrate-derived acid. All gypsum filter cakes prepared had a firm, sandy texture, rendering them physically suitable for stacking or landfill use. Introduction of dry attritioning and air classification approximately doubled the attainable filtration rate when the dry-beneficiated product was digested. In air classification, there was a 12-to 14-pct P205 loss. Depending on the technique used and the matrix grade, overall P205 recovery ranged from about 72 to 89 pct.

Jan 1, 1979

By Lloyd Carpenter

Eighteen elements were determined spectrochemically in vanadium metal and its compounds in the general range of 1 to 1,000 ppm by means of spark-ignited unidirectional arc excitation. The samples were converted to vanadium pentoxide and combined with a mixture of graphite, lithium carbonate, and gallium oxide. For the molybdenum determination, the oxidized samples were mixed with sodium chloride and packed in copper electrodes. Average precision of the method was 15.6 percent relative standard deviation and relative error was 4.4 percent.

Jan 1, 1963

By A. F. Jolly

In an effort to better predict the useful service life of friction rock stabilizer mine roof bolts in coal mine environments, the Bureau of Mines has evaluated the corrosion resistance of stabilizer steels in air-saturated and deaerated waters from seven Eastern and Midwestern underground coal mines. Accelerated electrochemical corrosion tests were used to estimate corrosion rates for the two high-strength, low-alloy (HSLA) steels used to fabricate Split Set stabilizers and for galvanized steel. Long-term static-immersion weight-loss tests were also conducted with the HSLA steels. Corrosion rates developed from the weight-loss tests (steady-state air dissolution) were roughly comparable to rates determined from electro-chemical testing in aerated waters. Although the highest rates occurred in waters with the highest chloride contents, rates in the other waters were low (<2.0 mpy) and exhibited little correlation to the widely varied chloride contents of the waters. The generally low corrosion rates are attributed in part to the tendency to deposit a protective CaC03 film, reflecting susceptibility to carbonate precipitation as indicated by positive Langelier (saturation) index values for the waters. With one exception, corrosion rates for the galvanized steel were (2.0 mpy. Rates with aerated waters were higher than those with deaerated waters. Pitting tendencies of the steels were also estimated.

Jan 1, 1987

By M. E. Adam

This report describes the construction and testing of large (30 ft high by 55 ft wide) stopping and overcast structures in an oil shale mine. The work was undertaken to develop construction techniques and cost data, and to measure leakage rates on full scale structures in an oil shale mine. A design data base was developed by reviewing industry practice, oil shale industry plans, and technical literature. Alternate layouts for room and pillar mining were examined to find ways to reduce the size and number of ventilation control structures. Six full size stoppings and one overcast were built in the Colony Pilot Mine. Leakage rates were measured using both SF6 tracer gas techniques and the ?brattice window? method. The leakage was measured both before and after a full scale face blast. Blast air pressures were measured across two of the stoppings. Cost and leakage data were used to evaluate the projected overall performance of various combinations of the stoppings in a two-panel oil shale mine.

Jan 1, 1986

By D. Harrington

"There is continued activity in connection with probable reopening of old-time silver producers, but this is largely offset by other obstacles which make metal mining in Colorado a rather precarious proposition. Discussions at the joint meeting of the Colorado chapter of the American Mining Congress and the Colorado Metal Mining Association in Denver, January 20, 21, and 22, brought out many interesting facts, among them that Colorado, once a producer of high-grade ores, and with freight rates, smelting charges, etc. to accommodate high-grade ores, is now compelled to depend almost wholly upon low-grade complex ores or abandon mining, In the face of this, the railroads threaten to advance freight charges, and smelters , because of decreasing tonnage, high labor, etc., must either advance smelting charges or close (the Globe Smelter et Denver recently closed, and it is said that the Salida Smelter will close in February). A serious menace is the possibility of increase of rates by companies supplying electrical power, and the threat of the agricultural interests, now in the saddle in Colorado, to alter the laws so as to greatly increase the burden of taxation to be borne by the mines.In order to stimulate interest in Colorado metal mining, the Colorado Metal Mining Association and Colorado chapter of the American Mining Congress have planned to have an elaborately staged exhibit in the Denver Auditorium during the latter part of the coming summer, This exhibit will reproduce an old time mining camp,including mining structures such as mills, headframes, etc., as well as the camp saloons, dance and gambling halls, etc., together with mineral exhibits from many of the old time mines, no abandoned, but possibly to be reopened. due to increased price of silver, Inasmuch as the Bureau of Mines plans a National First-Aid meet at Denver in August or September, and the Rocky Mountain Mining Institute will also hold its summer meeting in Denver, it seems advisable to hold the three meetings simultaneously and it is proposed to have this done.Labor supply is fairly abundant and apparently not inclined to be dissatisfied; few, if any, strikes or other labor disturbances being found. In some mining regions advances in wages were posted January 1 and no wage reductions are noted.The Rocky Mountain Coal Mining Institute held its meeting at Denver, January 20, 21, and 22, and much attention was devoted to methods of bringing down coal without use of explosives chiefly by undercutting and subsequent use of hydraulic processes of forcing down the coal. Some attention was given the question of labor and it was suggested that the time is at hand when labor unions should be made responsible bodies by incorporation or otherwise. It was agreed to hold the summer meeting in Denver simul-taneously with the holding of the National First-Aid. and Mine Rescue Meet.In general, coal production in Colorado is proceeding satisfactorily with occasional interruption by local strikes, and tonnage is up to that being produced before the strike, but not nearly up to the record of 1918. In general, the labor supply is plentiful, but demand for coal is by no means great and unless some cold weather intervenes, it is probable that the lignite mines will have to go to a three or four day a week basis. There have been no recent disasters, but the Pictou mine of the Colorado Fuel and Iron Company encountered a heavy supply of water, and had to be abandoned until such time as arrangements can be made to pump or bale the water out."

Jan 1, 1920

Reduce the potential of haulage related injuries in underground mines by providing a method for quickly assessing the state of repair of mine haulage track. The Problem Currently, there are no established standards or procedures for inspection or cleaning of underground mine haulage track. Many track defects are hidden from an inspector because of layers of dirt and debris on the ballast, spikes, fishplates, etc. When a visual inspection can be performed, it may be highly subjective, except for a few items that can be categorized or counted, such as missing bolts or spikes. Track inspectors may even become tolerant of defects that can gradually worsen. For these reasons, mechanical inspection methods are needed to supplement visual inspections. Approach The Bureau investigated this problem and designed a towed vehicle to both mechanically clean and inspect underground coal mine haulage track. The vehicle was developed using a systems approach, paying particular attention to human factors issues such as operator field of view, operator ingress-egress, control positioning, and seating design. The prototype was built using simple fabrication techniques and off-the-shelf components.

Jan 1, 1990

By G. M. Potter

During the investigation of the occurrence of manganese deposits in the western United States, examining engineers of the Bureau of Mines collected samples from four properties in Siskiyou and Mendocino Counties northern California. As the ores were too low-grade to be acceptable to manufacturers of ferromanganese, beneficiation studies were made between 1941 and 1945 to determine the amenability of the ores to concentration. The Johnson and Reynolds properties are near Fort Jones Siskiyou County. The ore occurs in a number of small lenses in that area. Samples were taken for testing for amenability to treatment in a small custom-gravity plant, tentatively planned. by the Waiter Johnson interests of San Francisco. A 2-ton representative sample was obtained from numerous exposed portions of an outcrop on the property of the Mayland Mining Co. The Mayland mine is about 8 miles from Sawyers Bar in Siskiyou County. The ore body consists of stringers and irregular masses of oxide, and. silicate ore scattered through quartz, which these minerals have replaced.

Jan 1, 1952

By A. E. J. Gallagher

This report summarizes the results of flotation studies conducted by the Federal Bureau of Mines on samples of extremely fine-grained lead-zinc sulfide ores. Samples from five ore deposits in the Pine Creek area, Coeur d&apos;Alene district, Idaho, and one deposit in the Metaline district, Washington, were studied at the Albany Metallurgy Research Center to determine the recovery of sulfide lead and zinc by flotation. During the investigation it was found that flotation could be effectively applied to the selective recovery of exceedingly fine-grained lead and zinc sulfide minerals. Separation of galena and sphalerite was obtained on pulps ground through 1,600-mesh, in which most of the particles were smaller than 5 microns. Selectivity and recovery of minerals in this fine size range were enhanced by use of a chemical dye, diphenylthiocarbazone, as a galena promoter. Although unsuccessful on one ore, application of the dye in treatment of two other very fine-grained ores yielded lead concentrates containing over 62 percent Pb at recoveries in excess of 85 percent. More than 55 percent of the lead in these concentrates occurred as particles smaller than 2 microns.

Jan 1, 1961

By Eugene Frey

"INTRODUCTION The Blue Bell fluorite deposits were examined in August and November 1944 by an engineer 3/ of the Bureau of Mines, and an underground project was set up. The Bureau of Mines began development of fluorite here February 10, 1945, and completed its survey on June 21, 1946.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepared the final report. The Metallurgical Branch, C. C. Ralston, chief, analyzes samples and perform beneficiaticn tests. The exploratory project was under the direction of Paul T. Allsman, chief, Salt Lake City Division, Mining Branch. Acknow¬ledgment is due R. Thurston of the Federal Geological Survey for mapping the topography of the area, and to F. H. Gunnell and W. A. Young of the divisional office for detailed mapping of the surface and underground development and interpretation of the results.The chemical analyses included in this report was performed under the direction of H. E. Peterson, analytical chemist; the petrographic studies on the ore were written by LaMar Evans, petrographer; and the beneficiaticn section was written by C. H. Schack, metallurgist, under the direction of S. R. Zimmerley, chief, Salt Lake City Division, Metallurgical Branch."

Jul 1, 1947

By Rogers F. Davis

The Bureau of Mines developed a new method for the determination of oxides of nitrogen in diesel exhaust gas. The procedure, a modification of the Saltzman method, uses a NO2 absorbent for the diesel exhaust gas; the colorless absorbent becomes purple on contact with N~. When used properly this procedure gives satisfactory results in 2 hours, whereas the standard phenoldisulfonic acid method required approximately 8 hours. The new method is not satisfactory for determination of oxides of nitrogen in the overrich fuel to air ratio range.

Jan 1, 1966

By Robert M. Doerr

The oxidation kinetics of Ni-Y alloys in the range 0.04 to 8 weight-percent Y, and of high-purity Ni, were compared by the use of a sensitive volumetric apparatus. The reactions followed approximately the parabolic rate law; for oxidations in 02 at 0.5 atm and 1,200° C, the parabolic rate constant was about 0.37 + (0.064) (Y-2.11) mg cm-2 min-1/2, where Y represents the weight-percent Y in the alloy. Internal oxidation of Y occurred in the alloy specimens and the resultant Y203 particles, which were in patterns related to the eutectic structure of the alloys, served as markers showing that the subsequent oxidation of the surrounding Ni was by inward diffusion of O. The scale consisted in each case of NiO, but the inner parts of the scale on the alloy specimens included the patterned Y203 particles. The thicknesses of the inner parts of the scale depended directly on the Y concentration, and the thicknesses of the Y2O3-free outer parts of the scale were inversely related to the Y content of the alloys. There is thus a relationship between the thickness of the outer part of the scale and the protectivity of the scale. Outward diffusion of Ni and inward movement of 0, from the inner boundary of the Y2O3-free part of the scale, is proposed as a mechanism for these results.

Jan 1, 1966

By H. R. Batchelder

Much information on oxygen production and the manufacture of synthetic liquid fuels has been published during the past several years. From time to tine the investment and operating cost of oxygen plants of various sizes has been estimated. Surveys have been made so that the various processes by which oxygen is produced commercially might be compared. The gas-making processes in which oxygen is employed, which wore used in Germany during the war, have been described in T.O.M. reels, and this information has been published. Descriptions of pilot-scale or proposed commercial plants for the production of synthesis gas or hydrogen and their conversion to synthetic liquid fuels also have been published. In general, each of these publications has dealt with a particular phase of the over-all problem. The present paper will discuss the relationship between these phases: The factors that affect oxygen manufacture and costs, the methods for the use of oxygen and for the production of synthetic liquid fuels, and, to some extent, the economic factors that must be considered.

Jan 1, 1951

By Paul S. Schopf

The results of an experimental investigation into the possible use of medium energy acoustic fields (130 to 140 dB) to precipitate 1 to 10 micron particles is presented. The aerosol was produced with a LeMer generator using oleic acid and nitrogen. The sound field was a sinusoidal standing wave field in an acrylic tube, with light transmission data used for concentration determination. The results showed collection efficiencies of up to 80% on 2 micron particles with a residence time of 11.8 seconds at a sound pressure level of 139 dB re 2x10-5 N/m2. A discussion of the possible turbulent mechanism is made, as well as review and comparison with others? work.

Jan 1, 1972

By John B. Gayle

The probable inadequacy of physical tests of coke for the purposes for which they are made has been a subject for discussion for many years. However, little has been published in this connection, even though most workers in the field believe that the physical properties of coke are of major importance in its utilization in the steel and allied industries. In fact, the reproducibility of the recognized tests is largely unknown or can only be approximated. This situation occasions many difficulties when attempts are made to judge the coke-production qualities of various coals or coal blends. During World War II the Coke Production Committee, composed of representatives from industry and the Solid Fuels Administration, concluded that study of existing testing methods and possible improvements would be of material assistance in answering questions relating to coke quality. Since that time the Bureau of Mines has taken samples of coke produced in industrial slot-type coke ovens in connection with studies aimed at extending coking-coal reserves by adding to the list of sources known to be suitable for this purpose. Testing procedures on these cokes were arranged so that the data obtained would yield information on (1) the degree of precision of tests commonly used in the industry, (2) the causes of the known poor reproducibility in several of the physical tests, and (3) possible improvements or modifications of existing physical testing procedures.

Jan 1, 1953