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By C. Melvin Lepper

High-resolution shallow seismic reflection methods are being used by the Bureau of Mines to map underground geologic features in coal mines. These features include faults, channel sand, washouts, rolls, and steep dips. The seismic method is proving useful for locating all of these at reasonable cost and with better definition than available with drill programs alone. This report provides a capsule description of the techniques and their application to mine planning.

Jan 1, 1976

By W. W. Odell

"It is common knowledge that extensive lignite deposits occur in the States of Montana, North and South Dakota and Texas. The total area of these deposits and the total amount of lignite in them is so great that the true economic value of lignite is seldom realized. These deposits underlie areas of thousands of square miles. The area of the lignite lands in North Dakota alone is estimated to be approximately 32,000 square miles. Nearly one-third of the total solid-fuel resources of the United States is lignite and approximately 90 per cent of this lies in the Northwest.To the people of the Northwest the more extended utilization of lignite is of fundamental importance, hence any methods for commercially producing salable products from lignite that promise further development of these great fields deserve careful study.The development of our lignite resources has been slow, partly because the districts wherein lignite is found is not thickly settled or highly developed in manufacturing industries, but also because of the physical and chemical characteristics of the lignite. Lignite is classed as a low-grade fuel and may be con¬sidered as imperfectly developed coal -which has a more or less woody structure; it may be of the brown-coal type or darker, denser and more homogeneous, approaching subbituminous coal in character. As mined it contains more than 30 per cent of moisture exclusive of the -rater of decomposition formed .then it is carbonized or burned. The heating value as determined by the calorimeter is approximately half that of good quality bituminous coal. Upon exposure to the air lignite loses part of its moisture, whereupon the lumps chock and split until after considerable exposure, a large percentage of slack is formed. It cannot be stored in large piles so successfully as come other fuels, and it some instances it is more apt to ignite spontaneously in storage or in transit then the higher grade fuels."

Feb 1, 1924

By J. E. Murphy

The Bureau of Mines developed a hydrometallurgical method for recovering mercury metal from mercury sulfide concentrates. Sulfide flotation concentrate from the McDermitt Mine was leached in a cupric chloride solution at 80° C. The redox potential of the solution was maintained at 850 mV during leaching by chlorine sparging. Mercury extractions exceeded 99 pct in 3 h of leaching. After leaching, the pH of the solu-tion was increased from 1 to 4.5 to precipitate copper as atacamite. The pregnant solution typically containing 100 giL Hg was sent to elec-trolysis to produce high-purity mercury metal and chlorine for recycle. In a 200-A electrolytic cell operated for 24 h, current efficiency was 99 pct and the energy requirement was 0.9 kW·h/lb of mercury produced. Mercury removal from the waste stream was also investigated. Iron or zinc cementation, sulfide precipitation with H2S, and activated carbon adsorption all decreased the mercury concentration from 10 giL to 0.01 mglL, which is less than the Environmental Protection Agency limit on wastewater of 0.02 mg/L.

Jan 1, 1987

By T. H. Dubaniewicz

Many mines rely on toxic gas sensors to help maintain a safe and healthy work environment. This report describes a prototype monitoring system developed by the U.S. Bureau of Mines (USBM) that uses light to power and communicate with several remote toxic gas sensors. The design is based on state-of-the-art optical-to-electrical power converters, solid-state diode lasers, and fiber optics. This design overcomes several problems associated with conventional wire-based systems by providing complete electrical isolation between the remote sensors and the central monitor. The prototype performed well during a 2-week field trial in the USBM Pittsburgh Research Center Safety Research Coal Mine.

Jan 1, 1995

By Donald P. Schlick

This report presents a representative cross section of methods success- fully used to ventilate continuous-miner places as well as various factors that should be considered when selecting auxiliary ventilating equipment. Line brattice can direct fresh air to the active face reasonably well, provided that adequate area for installation is available. Continuous mining equipment, however, often restricts clearances to such an extent that proper installation of line brattice is impossible. Consequently, in many instances face ventilation is inadequate; therefore, many methods of auxiliary ventilation for continuous-mining equipment have been developed and have been discussed in this study.

Jan 1, 1963

By P. E. Churchward

The Bureau of Mines developed a process using amines for recovering tungsten as ammonium paratungstate from alkaline leach liquors without producing synthetic scheelite as an intermediate product. Over 90 pct of the tungsten in low-grade scheelite or ferberite concen-trate was recovered as ammonium paratungstate by (l) autoclave leaching the concentrate with Na2CO3, (2) solvent extraction of the acidified leach liquor with kerosine solutions of either a quaternary amine (Aliquat 336) or a primary amine (Primene JM-T), (3) stripping the tungsten values from the quaternary amine with ammoniacal NH4C1 or from the primary amine with NH4OH, and (4) crystallization of ammonium paratungstate from the strip liquor. Reagent consumption in pounds per pound of W03 recovered was, for the quater¬nary amine, 3 Na2CO3, 3.5 H2SO4 , 2.2 NH4Cl, 1 NH3, and 0.4 glacial acetic acid; for the primary amine, it was 3 Na2CO3, 3.5 H2SO4, .06 NH4Cl, and 0.9 NH3. Both reagents extract molybdenum along with tungsten. Silicate and phosphate are partly extracted and contaminate the product; leach liquors containing these impurities require preliminary purification.

Jan 1, 1966

By Robert W. Geehan

"INTRODUCTION The Bureau of Mines, in cooperation with the Federal Geological Survey, explored the Crowell fluorite mine by core drilling in 1945. Claims investigated are in sec. 14, T. 12 S. R. 47 E., M. D. B. & M., in southern rye County, Nev., about 5 miles east of 'Beatty.The twelve holes drilled by the Bureau totaled 3,661 feet. During 1945 the mine operator drove extensive exploration drifts, in part to verify results of the Bureau's work. The drilling program was designed to test for extensions of ore bodies known in the mine.The Crowell mine has shipped Ore to steel plants on the west coast for the past 20 years. During the war this market called for all the fluorite the mine could produce, but previously there were periods when it was difficult to sell ore or concentrates.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Nines has as its primary objective the 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 prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Special acknowledgment is due to Glenn Allen, district engineer;A. C. Johnson, chief, Reno Division, Mining Branch; S. R Zimmerley, chief, Salt Lake City Division, Metallurgical Branch; W. R. Thurston of the Federal Geological Survey for advice on geological problems; and J. Irving Crowell, Jr., operator of the property, for his cooperation."

Nov 1, 1946

By D. C. Dahlin

The Bureau of Mines conducted laboratory batch beneficiation tests on samples from four potential platinum resources in southeastern Alaska to concentrate platinum and other precious metals. Thin Investigation was done as part of the mission of the Bureau to insure an adequate supply of minerals to meet the Nation's needs. Petrographic studies and beneficiation methods including gravity concentration, froth flotation, and magnetic separation were used to determine mineral association and to attempt to concentrate the platinum values with a primary mineral value such as chromite, copper sulfide, or magnetite. A high-graded sample from the Salt Chuck copper sulfide deposit yielded the platinum-group metal concentrate; the maximum grade attained was 0.04 oz Pt and 1.5 oz Pd per ton of high-grade copper sulfide concentrate. The other samples yielded low-grade primary mineral concentrates with low platinum-group values, and/or the platinum-group metals did not concentrate with the primary mineral value.

Jan 1, 1981

By James J. Dowd

The investigation to evaluate the reserves of coking coal in the United States suitable for the manufacture of metallurgical coke is being made by the Bureau of Mines in three parts: (1) To estimate known measured and indicated recoverable reserves of all coking coal; (2) to upgrade marginal coals through effective preparation; and (3) to study the carbonizing properties of coals and coal blends not now widely used for metallurgical coke making. This is the eighth of a series of reports giving the results of studies by counties under part (1) of the investigation. (See appendix.) This report covers Jefferson County, Pa., which comprises parts of Marienville, Hallton, Ridgway, Brookville, DuBois, Penfield, Smicksburg, and Punxsutawney quadrangles. (See fig. 1.) A short resume of the chemical and carbonizing properties of the coals is included. Data on the coal beds in the county were obtained from mining companies, land companies, individual landowners, and other sources of authentic information. A base map for each bed in each quadrangle was made to the scale 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all available data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds 0 to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick, These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and in each category, mined-out areas, areas excluded from the estimate, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1952

By J. A. Eisele

The Bureau of Mines is investigating the recovery of alumina from domestic nonbauxitic resources, including anorthosite. The United States has large reserves of anorthosite, but its aluminum content is less than 50 pct soluble in acid, unless a source of fluoride is added to the acid. A flowsheet that includes leaching with HCl and fluoride followed by crystallization of AlC13.6H20 from the pregnant liquor by HCl gas injection was designed. Approximately 90 pct of the aluminum values were recovered from the anorthosite when a ratio of 0.14 mole of fluorine per mole of aluminum was used. Sodium chloride is cocrystallized with the A1C13.6H20 but is removed by water washing of the Al203 product. A material balance is given based on results of laboratory studies of the unit operations.

Jan 1, 1983

By J. W. Town

As part of the Federal Bureau of Mines titanium resources examination program, samples from seven deposits in the Pacific Northwest were tested for amenability to various beneficiation techniques. The samples obtained by the Bureau's Office of Mineral Resources at Spokane, Washington represent a large potential source of titanium. This report summarizes the results of tests at the Bureau's Metallurgy Research Center, Albany, Oregon. Recoveries from tabling placer samples were about 50 percent at grades of 30 percent titanium dioxide. Flotation was the most effective method for concentrating the fine ilmenite in clay samples; recoveries of approximately 50 30 percent titanium dioxide. Flotation was the most effective method for concentrating the fine ilmenite in clay samples; recoveries of approximately 50

Jan 1, 1961

By A. A. Cochran

Methods of preparing small heats of steel containing radioisotopes were developed, and the techniques of stripping film autoradiography were used to detect and study the carbide and sulfide phases in titanium-bearing steels. Metallography had revealed areas of titanium sulfide and ferrite or pearlite adjacent to areas of titanium carbide and ferrite, and unidentified, irregular phases at the boundaries between these two areas. Sulfur 35 was used to deter-mine the extent of the titanium sulfide inclusions, and carbon 14 was used to delineate the titanium carbide phase. Individual radioactive areas were located with a resolution of approximately 10 microns. A general background exposure that was not correlated with microscopically visible phases was observed in the carbon 14 autoradiographs. The evidence from both sulfur 35 autoradiographs and carbon 14 autoradiographs indicated that the unidentified inclusions were sulfides rather than carbides. INTRODUCTION The use of radioisotopes to facilitate the work at the Rolla Metallurgy Research Center was expanded in fiscal year 1959 when the Bureau of Mines authorized the installation of an intermediate-level radioactivity laboratory. Before this time, sealed cobalt 60 sources had been employed for radiography, but no tracer work was done. The primary objective of the first experiments conducted in the new laboratory was to supplement physical metallurgy investigations of selected problems in steel research.

Jan 1, 1962

By J. R. Bartels

The U.S. Bureau of Mines has established a wire rope research laboratory to examine the factors that affect the life of wire rope. Two sin-diameter 6x25 fiber core (FC) ropes were degraded on a bending fatigue machine, These were the second and third ropes in a series of tests on this construction and size rope. Tensile and nondestructive tests were performed on samples of the rope to determine the relationship between rope deterioration and rope breaking strength. The tests indicated that once a wire rope nears the end of its service life, both deterioration and the consequent loss of rope strength begin to increase at an accelerated rate.

Jan 1, 2010

By Lawrence W. Scott

The performance of RETIMET metal foam as a flame arrester on explosion-proof enclosures was investigated by the U.S. Bureau of Mines both in laboratory tests and at the U.S. Mine Safety and Health Administration's (MSHA's) Approval and Certification Center, Triadelphia, WV. The objective of this research was to develop a permissible pressure vent for use on lightweight, vented, explosion-proof enclosures. In laboratory tests, four grades of RETIMET, a stainless steel foam material, were evaluated: (1) 45 NC-7, (2) 45 NC-13, (3) 80 NC-7, and (4) 80 NC-13. Explosive gas mixtures were prepared by a dynamic flow system. Ignition was by a low-voltage arc. Each grade of RETIMET metal foam successfully arrested the flame front in all methane-air tests. To evaluate RETIMET metal foam on large, commercial size enclosures,a multi compartmented enclosure was designed and tested in MSHA's explosion gallery in Triadelphia, WV. Extensive explosion testing revealed that a minimum vent-area-to-enclosure-volume ratio of 11.33 in2/ft3 is required to keep internal pressure rises below 3 psig. The RETIMET metal foam functioned satisfactorily in all tests as evidenced by the absence of external ignitions.

Jan 1, 2010

By David L. Veith

Caustic scrubbing followed by silica flotation with cationic ether primary amine proved effective in upgrading commercial magnetic concentrates to supergrade products containing 2 percent SiO2, or less. Samples representing 41 million long tons per year of commercial magnetic concentrates from the Lake Superior region were tested by the Bureau of Mines. Bench-scale and pilot plant research indicated an estimated potential of 32 million long tons per year of superconcentrates to be available. Two pilot plant investigations yielded superconcentrates containing 1.1 and 1.9 percent SiO2 that were derived from commercial concentrates containing 7.0 and 4.2 percent SiO2, respectively. Corresponding iron recoveries were 90 and 93 percent at reagent costs of just over 33 cents per long ton of superconcentrates produced. Additional sources evaluated on a bench scale resulted in iron recoveries of 72 to 95 percent in products containing 1.7 to 2.0 percent Si02. Although reagent cost ranged up to 60 cents per long ton of superconcentrate, it is probable that these costs would be reduced in plant applications where benefits are derived from material and reagent recycle.

Jan 1, 1974

By G. W. Grove

Coal-mine officials and those who are preparing to become officials should be familiar with the instruments and devices that are employed rather commonly in and around mines and should know how to use them with safety and efficiency. Among these axe instruments and devices used in determining the pressure, velocity, volume, and certain other conditions of ventilation and in detecting the more common mine gases, such as methane, carbon monoxide, and hydrogen sulphide, or a deficiency of that very important agent, oxygen. Water gages, anemometers, barometers, psychrometers, flame safety lamps, lamp-testing boxes, and methane, carbon monoxide, and hydrogen sulphide detectors are described and their use and operation discussed in this paper.

Jan 1, 1938

By Louis A. Panek

The practice of roof bolting, now recognized as an effective method of support, is based largely on rule of thumb. Among the various applications of bolting, the support of stratified mine roof is by far the most common. The general principles relating to this type of reinforcement are presented in two companion reports; the first describes the function of the bolts, the bolting pattern, and the behavior of bolted roof (1), 2/ and the second describes the design of the models and the theory of the experimental method (2). This report presents a rational method for designing systems of vertical bolts to reinforce horizontally bedded mine roof, developed from model tests. The structure treated herein may be described as follows: The immediate roof, consisting of beds of like material and equal thickness with no bond between them, is reinforced by vertical bolts installed in straight lines across the opening; the case of suspension is excluded because the bolts are assumed not to extend above the immediate roof. The assumption is made that the behavior of the lowest bed approximates that of a rectangular plate clamped along two opposite sides (the ribs). These specifications represent approximately the roof conditions encountered in mining bedded deposits of all kinds - coal, potash, iron ore, etc. Thus, for the design of a roof-bolting system a quantitative solution to the following problem is required: For a roof composed of beds of given thickness and physical properties, how does the support depend upon the length, spacing, and tightness of the bolts?

Jan 1, 1956

By D. J. Parker

Before the various States began to enact workman's compensation laws accidents were considered inherent in many industries, and little or no effort was made to prevent or reduce them. The hazard was accepted by the employee with the job, and the avoidance of accidents by mental alertness or physical agility was largely his responsibility. After the employee had given evidence of enough skill inn performing his allotted task efficiently the responsibility of the employer apparently ceased with respect to the personal safety of the employee. However, following the enactment of workmen's compensation laws, at least two facts that had not before been fully appreciated soon became apparent: (1) The majority of accidents can be prevented if the management firmly determines to prevent them; (2) frog a monetary point of view alone accidents are decidedly expensive, both to employer and to employee. It is now evident that savings effected by conscientious safety effort add substantially to net profits of operation.

Jan 1, 1934

By Robert J. Timko

Because of leakage through and around permanent stoppings in underground mines, more air must be forced into a mine than would otherwise be required for ventilation. As power costs increase, costs resulting from air leakage add increasingly to the operating costs of mining. The Bureau of Mines evaluated four different stopping construction techniques based on the ideas that (1) airtightness could be enhanced by brushing rather than troweling on mortar sealant and that (2) modified mortars (mortars containing glass fibers and other additives for increased strength and adhesion) would improve sealing performance. Air leakage tests comparing conventional to modified stoppings were done when the stoppings were built, after 6 months, after 1 yr, and following simple maintenance. It was found that stoppings can be built and maintained better if-- The area where a stopping is to be built is properly prepared. Stoppings are constructed using the techniques devised by the Bureau. Stoppings are periodically examined for leaks. Stoppings found to be leaking, especially at the perimeters, are resealed.

Jan 1, 1983

By P. G. Clites

A laboratory furnace was developed by the Federal Bureau of Mines for use in studying the interrelationships among variables associated with skull melting and casting high-temperature metals. Although additional work is necessary to determine the extent to which the information obtained by using this furnace can be extrapolated to larger furnaces of the same type, many casting characteristics of metals and alloys can be determined on equipment of this size. This furnace is a laboratory-size, consumable-electrode, skull-casting furnace equipped with a water-cooled copper ladle. The ladle, which is a tilt-pour or over-the-lip type, has a volume of approximately 30 cubic inches and provides up to 20 cubic inches of molten metal for castings. Castings of various reactive and refractory metals, including zirconium, titanium, hafnium, columbium, molybdenum, tantalum, and tungsten, have been produced. In addition, castings of iron, chromium, and copper have been made. The simplicity and versatility of the apparatus would make it useful to metallurgical laboratories preparing cast specimens.

Jan 1, 1961