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By R. L. Grant

An investigation was undertaken by the Bureau of Mines to determine the relationship between freespace and ignition probability for borehole shots. A series of experiments was concluded which covered six freespace conditions for a pemissible explosive in a 3/4-inch borehole and encompassed some 700 shots. The results were analyzed statistically. From the analysis of variance, it was concluded that the freespace means were different and that this conclusion is not impaired by possible differences in the explosives used. Within the limitation of this experiment, a definite relationship was found between the freespace and the ignition probability. Specifically, the incendivity increases with increased freespace up to a maximum; beyond this maximum there is some indication of decreasing incendivity. Further investigations are in progress to establish whether the effects of freespace on ignition probability reported here are applicable to the large test gallery, INTRODUCTION A borehole loaded with an explosive charge is a common feature of the routine gallery tests for determining the permissibility of coal-mine explosives, of Experimental Coal-Mine shots, and of the small steel cannon shots used in connection with certain research programs on the ignition of firedamp (6, 10).6/ The question of the interrelationship of freespace, weight of charge, and ignition probability of the methane-air atmosphere has been raised

Jan 1, 1959

By Gary M. Larwood

A study was conducted to determine the amount of transportation equipment required to move 1.2 billion tons of coal in 1985. The Federal Bureau of Mines has investigated a majority of the various practices associated with coal transportation and has gathered information on the regional origin-destination patterns, methods of movement, equipment stocks, rate structures, and operational capacities of the most important modes of coal haulage currently in use. Models employing this information were developed to establish the origin-destination pattern for 1985 coal shipments, estimate practical tonnage capacities for selected coal hauling rivers, develop modal shares for both unconstrained (by river capacity) and constrained cases, and present a range of coal transportation equipment requirements for given sets of constraints. Projected transportation shares for rail ranged from 63.7 to 72.3 percent, and for river, from 8.8 to 16.4 percent. Other coal transportation modes (truck, conveyor, Great Lakes, and tidewater) are expected to retain their historic shares of coal traffic. Equipment estimates were made for 1985 rail and water transportation based on 1973 average and best practice. Average practice estimates ranged from 675,000 to 710,000 hopper cars (100-ton) and 3,100 to 5,940 barges (1,400-ton equivalent). Best practice estimates ranged from 126,000 to 142,000 hopper cars and 1,750 to 3,450 barges. Full implementation of 1973 best practice by 1985 is unlikely.

Jan 1, 1976

By Edwin S. Secor

The Federal Bureau of Mines conducted a field survey of 153 bituminous coal strip and auger mines to estimate coal recovery from surface mines in the Eastern United States. Recovery was calculated from field data by measuring coal losses resulting from mining coal and leaving barriers. Mean total recovery for strip mining in States east of the Mississippi River was 83.0 percent and ranged from 72.3 percent for Tennessee to 91.3 percent for Maryland. Mining losses and barrier losses were 10.1 and 7.7 percent, with standard deviations of 4.8 and 10.4 percent, respectively, indicating that barrier losses, although less than mining losses, were more variable. Mean total coal recovery varied only slightly for the two regions studied; 82.7 percent for Appalachia and 84.3 for the Midwest. Total recovery grouped by mining method--contour, area, and mountaintop removal--was 79.8,84.7, and 85.3 percent, respectively. Mean auger recovery was 35.9 percent; of the total average loss of 64.1 percent, over one-half resulted from design limitations while the remainder was attributed to operating losses. The wide recovery range at individual mines indicates the variability of the eastern surface coal mining industry. Because of this, care should be exercised in applying the results of this report to reserve estimates other than those of a general nature.

Jan 1, 1977

By Lowell B. Moon

Concern over possible wartime shortages finally resulted in passage of the Strategic Materials Act in 1939. As authorized by one section of this legislation, the Bureau of Mines proceeded to investigate deposits of seven strategic minerals with the objective of developing tonnages of low-grade material that could be mined in an emergency. During the war, the size of the program and the number of strategic minerals were increased, and the objective was the more immediate one of aiding production. Since the war, the size of the program has been reduced, but the number of minerals on the strategic list continues to be large. The objective has returned to that of 1939. In the course of the program, more than 10,000 examinations were made and about 1,300 projects were run on deposits of 33 different commodities. A considerable contribution to war production was made in six of the commodities investigated, and a minor contribution was made in twelve others. Substantial reserves have been indicated in 19 minerals. Private interest is currently active in some of the deposits developed in 14 commodities.

Jan 1, 1950

By C. E. Armantrout, H. Kato, M. I. Copeland, M. Krug

The investigation of the nickel - gadolinium phase diagram was undertaken to determine the alloying behavior of these two metals . The data from meltingpoint determinations , thermal analyses , metallographic examinations , and X- ray diffraction analyses revealed a phase diagram with three eutectic points and seven intermetallic compounds . Very limited solubility of the phases in each other was observed . The five phases , Ni Gd , Ni , Gd , Ni Gd , Ni, Gd , and NiGd¸ , melted incongruently at about 1,300 ° , 1,270 ° , 1,180 ° , 1,070 ° , and 775 ° C , respectively . Ni Gd and NiGd melted congruently at approximately 1,550 ° and 980 ° C , respectively . Four of the compounds were determined to crystallize in the hexagonal system : Ni Gd , Ni Gd , Ni , Gd , and Ni Gd . Ni Gd was determined to be cubic and NiGd , orthorhombic . The crystal system of NiGd was not determined . The eutectic points occurred at 13 , 67 , and 85 wt pct gadolinium , and the isotherms at 1,290 ° , 890 ° , and 700 ° C , respectively .

Jan 1, 1964

By Robert L. Montgomery

Heats of solution of samarium (III) oxide and chloride in hydrochloric acid and of samarium (III) oxide, sulfate, and hydrated sulfate in sulfuric acid were measured. The heats of solution of this hygroscopic oxide are larger than those from the literature, probably because of more complete removal of water in the present study. From the literature value for the heat of combustion of samarium, the heats of formation of samarium (III) chloride and sulfate are -244.18 ± 0.41 and -928.5 ± 1.6 kcal./mole, respectively. The heat of hydration of the sulfate is -34.7 ± 1.0 kcal./mole. The heats of formation of other samarium com-pounds have been recalculated, using the new data.

Jan 1, 1959

By A. C. Johnson, es Hol, E. O. Binyon

"INTRODUCTION AND SUMMARYThe tungsten properties of Lincoln Mines, Inc., and North Tem Flute Mining and Development Co. were first explored by the Bureau of Mines in 1942. Work on the project comprised trenching, sampling, a small amount of road and trail construction, and a small amount of core drilling. From April 13 to December 10, 1944, additional diamond drilling was done by the Bureau of Mines to test the lateral and downward extensions of the various tactite zones along the contact south of the Lincoln mine, including the property of the North Tem Piute Mining & Development Co.Claims leased by the Lincoln Mines, Inc., are in secs. 25 and 36, T. 3 S., R. 56 E.; secs. 30 and 31, T. 3 S., R. 57 E.: and sec. 1, T. 4 S., R 56 E., M. D. B. & M., in the Tem Piute Mining District, near the north end of the Timpahute Range in west central Lincoln County, Nev. D. B. Fegles is president of Lincoln Mines, Inc. and general offices are in the Wesley Temple Building, Minneapolis, Minn.In June 1945, the Atolia Mining Co. leased the property and purchased the mill and mining equipment from Lincoln Mines, Inc. P. R. Bradley is president of the Atolia Mining Co., whose offices are in the Crocker Building, San Francisco, Calif. This company surrendered the lease on the property on September 30, 1948. The property owners are continuing operations and are now engaged in building a 20-ton mill.The claims of the North Tern Flute Mining & Development Cc. are in sec. 1, T. 4 S., R. 56 E., M. D. B. & M. Merle F. Schofield is president of the company and maintains an office at Hike, Nev. These claims were leased by H. P. Laslett, of the Utah Nevada Mining Co., in 1945 and by the Atolia Mining Co. in 1946. The owners are now doing some exploratory work."

Jan 1, 1950

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions4/ issued by the Bureau of Mines, the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1957

By R. Blickensderfer

The laboratory wear testing capabilities of the Bureau of Mines are described, Wear tests are used to support the Bureau?s research efforts toward reducing the wear of equipment used for mining and minerals processing and any wear involving a loss of strategic or critical materials. The emphasis is on abrasive wear because it accounts for most of the wear losses that occur in mining and minerals processing equipment, Spalling wear, caused by repetitive impact in grinding equipment, also is included, Ten abrasive wear tests, including high- stress and low-stress and two-body and three-body conditions, are described: dry-sand, rubber-wheel abrasive wear; Taber Abraser; abrasion resistance of refractory materials; dry-particle erosive wear; elevated-temperature, dry-particle erosive wear; low-angle slurry pot; jaw crusher gouging wear; ball mill wear; pin-on-drum abrasive wear; and high-speed impact gouging. Two repetitive impact tests are described: ball-on-block impact-spalling and ball-on-ball impact-spalling. Test equipment, procedures, and specimens are described, and typical test results are presented and discussed.

Jan 1, 1985

By John A. Ruppert

1. It has been proposed that the addition of enough limestone to an open -hearth s lag to give a CaO-3P2O5 ratio of approximately 2-followed by SiO2 firing in an oxidizing atmosphere under the proper conditions of time and temperature will result in a clinker having a magnetic phase containing a preponderance of Mn, Fe, Al, and Mg as oxides and a nonmagnetic phase consisting for the most part of a phosphorus-containing dicalcium silicate. It has been postulated further that the metal oxide phase can be recovered by fine grinding and magnetic separation. These broad principles have been substantiated by numerous clinkering operations made in an electrically fired studio-type kiln, a batch rotary kiln, and a continuous rotary kiln and by magnetic separations made in a Davis -tube separator and a laboratory-size Jeffrey-Steffensen three -roll continuous separator. 2. Quenching the clinker after firing seems to improve its grindability. Microscopic examination of the ground clinker indicates .that the oxide phase grinds down at a somewhat faster rate than the silicate phase. 3. Very fine grinding is necessary to approach liberation, of the oxide phase from the silicate phase. Grinding to ininus-325-mesh, followed by magnetic separation, gave only a rougher concentrate, which had to be reground before final separation. 4. Although the manganese content of the final concentrate was higher, there was some evidence that manganese recovery was lower from a clinker made from a flush s lag than one made from a mixture of tap and flush slags. A possible explanation is that a clinker made from a mixture of slags has a higher iron content and hence is more magnetic and more easily separated.

Jan 1, 1952

By Peter N. Gabby

A mineral purvey of 40,000 acres of the 42,213-acre Little Humboldt River Wilderness Study Area was conducted by the U.S. Bureau of Mines in 1985 at the request of the U.S. Bureau of Land Management. There are no identified mineral resources but anomalous gold, silver, mercury, and arsenic concentrations were found. The study area is located in Elko County, NV, in the Owyhee Upland geomorphic subprovince. It is underlain by mid- to late-Miocene-age rhyolite, basalt, tuff, vitric ash, and tuffaceous siltstone. On the south side and partly within the study area, a mining company recently (January 1986) located 125 contiguous claims over an area of hydrothermally-altered volcanic rocks that have anomalous surface concentrations of gold, mercury, arsenic, and silver. Anomalous gold-silver concentrations in altered rocks were encountered at several other widely scattered localities in the study area. These elevated metal concentrations and associated hydrothermal alteration indicate gold resources may be present in the study area. A 20-ft-thick bed of diatomaceous earth, which contains 60 to 85 percent diatoms, crops out 0.3 mi north of the study area. Elsewhere, three samples of altered volcanic tuff taken within the study area contain from 46 to 70 percent zeolite (clinoptilolite). The diatomaceous earth and zeolite sampled are not of sufficient quality to compete with materials presently being marketed. There has been no mineral production from the study area, but a caved adit, about 25 ft long, and six prospect pits were found.

Jan 1, 1987

By Wallace W. Roepke

The Bureau of Mines tested new designs of drag bit cutters with sintered diamond inserts instead of standard tungsten carbide tips. The bits were tested for orthogonal cutting forces, primary dust generation, and incendivity, with a standard plumb-bob type conical cutter (600 included tip angle) as the reference. Preliminary wear and impact-failure testing were also done. The results were mixed. Two new designs had forces similar to those of the reference bit, but one new design had about twice the normal force. This same design had almost twice the specific energy during shallow cutting but generated an equal or slightly lower amount of primary dust than did the reference bit. Incendivity was eliminated for two radial designs. One conical design had ignition only after more than 15 impacts, but the other conical design was incendive. Impact failure occurred, but not so quickly as anticipated. Over 7,500 impacts on a sandstone face, with a total cutting distance of more than 1,981.2 m, only scuffed the leading edge of the sintered diamond cutting face but put hairline cracks in the substrate mounting pad. Additional design and testing are needed to develop an optimum cutter, but prospects look good for this material.

Jan 1, 1983

By G. S. Scott. R. L. Grant

Ammonium nitrate (NH4NO3), a white crystalline chemical compound composed of 35 percent nitrogen, 60 percent oxygen, and 5 percent hydrogen, has again attracted attention, due largely to the recent catastrophe on April 16 and 17, 1947, at Texas City, Tex. The fire and subsequent explosion on the steamship Ocean Liberty, outside the harbor of Brest, France, on July 28, 1947, has fur- ther increased the interest in the properties of ammonium nitrate. As a result of the Texas City disaster, several laboratories have undertaken research to determine more certainly what causes ammonium nitrate to detonate and under what circumstances. This is not the first time that ammonium nitrate has been involved in a disaster, and its properties reviewed from the standpoint of safety. The disaster at Oppau, Germany, in 1921, which involved an equimolec- ular mixture of ammonium nitrate and ammonium sulfate, prompted an intensive study in Europe and in America. In the United States the properties of am- monium nitrate are now of especial concern because very large quantites are being manufactured and shipped in interstate commerce and abroad. Many an- monium nitrate factories, which were built during the war, will manufacture increasing amounts of this compound for use as a fertilizer. It is the purpose of this report to present a brief summary and biblio- graphy of the published experimental facts about the properties and behavior of ammonium nitrate. The reader is referred to original publications for greater details of the investigative work, and for theoretical discussions. This report also includes a survey of ammonium nitrate fertilizer of the type involved in the Texas City explosions. In the past, authorities have not always agreed on the degree of hazard involved in the manufacture and handling of ammonium nitrate, as the following quotations from the literature indicate: Munroe (82) quoted the following from Turner's Chemistry (a book pub- lished in 1835): "When this salt is exposed to fire, it liquefies, emits aqueous vapor, dries and detonates." Berthelot (14) in his book, Explosives and Their Power, 1983, wrote: "Ammonium nitrate from the point of view of its volatility, and cn account of many considerations, may be regarded as a typical explosive substance."

Jun 1, 1948

By Henry Kreisinger, L. P. BRECKENRIDGE, WALTER T. RAY

The investigations of fuels conducted by the technologic branch of the United States Geological Survey had their inception at the Louisiana Purchase Exposition in 1904. By an act approved Febru- ary 18, 1904, Congress authorized the work of analyzing and testing at the Louisiana Purchase Exposition the coals and lignites of the United States, under the supervision of the Director of the United States Geological Survey. An appropriation of $30,000 was made for this purpose. In the general deficiency bill dated April 27, 1904, the sum of $30,000 was added to the appropriation. To carry out these investigations the Director of the Geological Survey appointed a committee consisting of E. W. Parker, statistician of the Geological Survey; Joseph A. Holmes, State geologist of North Carolina; and Marius R. Campbell, a geologist of the Geological Survey. Under the first act authorizing this work all of the machinery and coal for the tests was to be furnished the Government free of charge. The buildings containing the testing apparatus were all paid for out of the first appropriation. After the close of the Louisiana Purchase Exposition every Congress made an appropriation for continuing these fuel tests. These subsequent appropriations permitted the purchase of appliances better adapted for the testing work.

Jan 1, 1912

By I. F. Avery

The productive capacity of natural-gasoline and cycling plants in the United States on January 1, 1958, was 48.8 million gallons per day, according to the Bureau of Mines biennial survey. This represented an increase of 2.4 million gallons per day during the 2-year period since the last survey. In the previous 2-year period, capacity had increased 7.5 million gallons per day. The major increase in operating capacity occurred in Texas and New Mexico. In New Mexico, capacity increased 43 percent. The total number of plants decreased from 600 on January 1, 1956, to 584 on January 1, 1958. The number of operating plants decreased from 571 to 558. Five new plants were completed in Colorado, increasing the number of operating plants from 7 to 12.

Jan 1, 1958

By S. L. McGill

The U.S. Bureau of Mines has determined the microwave heating rates for a suite of minerals and reagent-grade compounds. Maximum temperature achieved for the samples and the time required to reach temperature are reported. Heating rates of powdered samples are presented as a function of incident powers up to 3,000 W at 2,450 MHz. Descriptions of the microwave cavities, test cells, and a thermocouple assembly used to measure temperature in the microwave field are given. Many minerals of value heated in the microwave field, whereas host rock or gangue materials did not. In general, heating rates increased as incident power was increased. Exceptions to this were some very good (CuO, Fe304, and PbS) and very poor (CaC03 and SiO2) microwave-absorbing materials that showed negligible changes with increased power. Applications demonstrating the use of microwave energy in mineral processing that are described herewith include oxidation-reduction reactions, mineral liberation, and mercury retorting-vaporization. Microwave data on mineral heating rates will provide insight to possible chemical and mineral processing applications as well as assist in predictions of processing parameters.

Jan 1, 2010

A symposium on the health hazards of respirable dust in the mining and milling of talc was held on May 8, 1973, in Washington, D.C. The results of medical effects on both human and animal subjects were presented. Methods for identification and classification of talc minerals were also presented. Analytical techniques discussed included X-ray diffraction, scanning electron microscope observation, electron probe, and optical microscopy.

Jan 1, 1974

By R. M. Creamer

Attempts have been made to electroplate titanium and zirconium from aqueous, nonaqueous, and fused-salt electrolytes. Metals were produced only in fused-salt electrolytes, the major product being sponge metal. All other electrolytes gave only partial reduction of the metal ions. Fused alkali borate electrolytes containing titanium salts gave titanium boride powders and coatings of poor adherence. Some of the problems encountered in the deposition of these metals and some of the aspects of titanium and zirconium chemistry involved are discussed. INTRODUCTION Titanium and zirconium are both relatively light, noncorrosive metals with both military and civilian uses. This has led to intensive investigations into the metallurgy of these metals. Both metals are high in the Electrochemical Displacement Series and are difficult to prepare in a pure state. At present they are prepared by reducing their chlorides, using magnesium. Electrolytic reductions have resulted in the preparation of fine powders or sponge of variable quality. It is believed that a good process of electroplating these metals on a baser metal would result in a very desirable product. The objective of the research summarized in this report was to investigate methods of electrodepositing these metals, with the idea of producing uniform, coherent plates. Most of the work was concentrated on titanium, the more abundant of the two metals. A system developed for titanium should be applicable to zirconium owing to their chemical similarity. Information gained from these experiments may also be applicable to the electro-winning of the metal.

Jan 1, 1954

By Bruce I. Thomas

As a part of the United States Department of the Interior program for developing natural resources in Alaska, the Bureau of Mines studied the tin-bearing gold-placer deposits in the Tofty area of the Hot Springs district in central Alaska. The principal objective of the Bureau's work was to obtain facts about the extent and character of the placer deposits (including tailing) to indicate the economic or strategic tin-production potential of the Tofty "tin belt." A secondary objective was to determine (if possible) the bedrock Source of the cassiterite and other minerals found in the placer deposits. The placer phase of the work was begun in July 1954 and was continued during the 1955 and 1956 field seasons. Extensions to, and connections between, known placer channels were sought by 82 churn-drill holes. The Bureau drilling did not expand the placer deposits beyond the limits established by drift-mining operations and by previous drilling done by private concerns.

Jan 1, 1957

By R. J. Kuczynski

The U.S. Bureau of Mines operated a 2,000-g (4.4-lb) batch process development unit for recovering platinum-group metals (PGM) from automobile catalysts. Virgin monolith, used pellet, and used monolith catalyst samples were tested. Leaching twice with 1-pct sodium cyanide (NaCN) solution at 1600 C for 1 h dissolved more than 95 pct of the PGM from virgin catalysts and more than 90 pct from used pellet catalysts. More than 85 pct of the PGM was dissolved from used monolith catalysts when a third autoclave step was added. Solid PGM concentrates containing more than 99.8 pct of the dissolved PGM and analyzing greater than 70 pct PGM were recovered by heating the pregnant leach solutions from virgin catalysts to 2500 C and used catalyst to 2750 C for 1 h. The solution after heating contained less than 0.2 ppm. total cyanide. The virgin residues passed the EPA Extraction Procedure Toxicity Test (EP Tox Test), the EPA Toxicity Characteristic Leaching Procedure (TCLP), and the California Waste Extraction Test (WET) for all elements except Ba. Adding sodium sulfate (Na2S04) to the virgin leach residues reduced the amount of Ba dissolved to an acceptable level. The used leach residues passed the EP Tox Test for all elements but failed the WET and TCLP for Pb.

Jan 1, 2010