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By David J. Kusler

This report describes a rapid, reliable, and relatively simple method developed by the Bureau of Mines Pyrometallurgy Laboratory at Bruceton, Pa., for determining lime (calcium oxide) and magnesia (magnesium oxide) in various materials containing these constituents in greater than trace amounts. Optionally, titania (titanium dioxide) may be determined for the same sample. The accuracy of the method, suitable for most purposes, is shown by comparing the Bureau results with those obtained by accepted procedures. The method has been applied satisfactorily to the routine analysis of blast-furnace slags, for which purpose it was primarily developed, and to other calcareous compositions. In the Pyrometallurgy Laboratory it has replaced the standard methods previously used to determine lime and magnesia, and has been in general use by that laboratory for the past several years. The analysis time, generally under 3 hours, is considerably less than required by standard methods.

Jan 1, 1960

By V. R. Miller

The Bureau of Mines investigated methods for testing the tensile and sheer strength of cast specimens of bulk solder and of soldered joints in order to increase the strength and extend the useful temperature range of soft solders. A spread-area test for determining the wettability of solder on copper surfaces was developed. Mannitol was used as a flux in spread tests to control spreading and to avoid plating, etching, and other side effects of regular fluxes. Data on commercial and high-purity solders obtained by these methods show more consistency than those reported by others from similar tests.

Jan 1, 1967

By J. Douglas Causey

The Bureau of Mines conducted mineral investigations of the Peace Rock and Deadwood River roadless areas in Idaho, in 1992. Literature research was done by the Idaho Geological Survey. The study areas contain black sand placers (thorium, columbium, tantalum, titanium, uranium, and rare earth elements), gold, and molybdenum prospects. Except for unrecorded placer gold, there has been no mineral production from the areas. No mineral resources were delineated, but a multi-million tonne molybdenum resource is in the Big Pine Creek area and a 142 million m' black sand deposit is in the Stolle Meadows, Peace Valley, and Deadwood River areas. The Deadwood mine produced zinc, lead, and silver. There are six mining districts in and adjoining the areas; Warm Lake, Deadwood, Garden Valley/Lowman, Banner, Summit Flat, and Grimes Pass. Few claims, mostly placer, were active in the study area in 1992. The study areas are underlain by granitic rocks of the Idaho batholith. Most of the deposits are alluvial accumulations of heavy minerals weathered out of the Idaho batholith. Stockwork and narrow veins along shears account for the base and precious metal concentrations. Eleven prospects were examined. Workings consist of drill holes, pits and adits. Geothermal resources (hot springs) occur mainly along the Middle Fork Payette River; Vulcan Hot Springs is a designated Known Geothermal Resource Area. Sand and gravel resources are of local interest.

Jan 1, 1993

By Manuel Gomez

The heat contents of thermally dried lignite, subbituminous B coal, and their corresponding low-temperature chars were determined at various temperatures below the highest temperature to which these materials had been exposed before testing. Similar studies were made on high-temperature char and coke, spent shale, and ash prepared from both coal and spent shale. Heat content of the carbonaceous materials tested correlated well with temperature. Heat con-tent results for spent shale compared well with the published results. Statistical analysis of experimental data together with published information showed moisture, volatile matter, carbon content, and temperature to be the principal variables influencing the specific heat of coal. The specific heat of devolatilized carbonaceous substances, char and coke, approached that of graphite as the carbonization temperature was increased. The elemental specific heats of coal constituents, estimated from the ultimate analysis and the specific heat of coal, compared favorably with published elemental specific heats.

Jan 1, 1965

By C. M. Mason

The current Bureau of Mines active list of permissible explosives includes 95 brands. Twelve are gelatinous and the rest are the more commonly used granular ammonium nitrate type. The list of permissible blasting devices comprises five Cardox models.

Jan 1, 1968

By M. J. Kovalik, D. E. Wolfson, F. Fischler

Plastometric tests were made to determine the maximum thickness of the plastic layer for different U.S. coals . The effect of test variables on the maximum thickness of the plastic layer was studied . The values for the maximum thickness of the plastic layer were found to be related to the Gieseler maximum fluidity , plastic temperature range , free swelling index , and other plastic properties of coals . Only a general relationship was observed between the plastometric parameters obtained in these tests and the coking properties of coal .

Jan 1, 1964

By R. W. Stahl

Increasing use of continuous miners, especially the boring type, has focused attention on the inadequacy of face ventilation in coal mines. The bulk of the machine, the rapid advance of working faces, and the increased liberation of methane from the larger expanse of freshly exposed coal surfaces have created ventilation problems that were unknown with conventional mining equipment. Ignition of gas, especially that caused by machine bits striking hard rock or pyritic inclusions, have increased at an alarming rate. As the mines penetrate beds under thicker cover at an ever-increasing rate of face advance, this problem will probably increase unless face ventilation is improved. A previous survey, described in Bureau of Mines Report of Investigations 5414, Auxiliary Ventilation of Continuous Miner Places, disclosed that auxiliary fans with tubing generally improved circulation of air and removal of gas at the face. The study here reported attempts to examine, face ventilation at various mines and to note any plan or innovation of. air coursing that industry might adopt to reduce the danger of gas ignition. ACKNOWLEDGMENT The mines visited were very cooperative in the study-and-generously supplied any data requested.

Jan 1, 1960

By E. G. Erspamer

Laboratory investigations were made by the Bureau of Mines on ore containing the sulfides of both mercury and antimony to develop a method or methods for the economic recovery of mercury metal and the concurrent recovery of antimony as metal or salts,. If standard mercury-recovery techniques are applied to such ores, the antimony content interferes with the effective production of mercury metal; further-more, the antimony is lost. This report presents the results of tests on a sample of cinnabar-stibnite ore from the Red Devil mine near Sleitmute, Alaska. Red Devil ore was chosen for the investigation because it is purported to be typical of ores of the Kuskokwim River area, which, in their aggregate, constitute large potential reserves of mercury and antimony. Studies included petrographic, spectrographic, and chemical analyses, gravity-separation tests, bulk flotation of mercury and antimony sulfides, differential flotation, leaching, and furnacing of crude ore and of flotation concentrate.

Jan 1, 1956

By R. R. Schehl

The Bureau of Mines analyzed the structure of a high-grade metallurgical coke, carbonized at different temperatures in the range 500° to 1,000° C, through X-ray diffraction studies. Growth in the crystallite size with increasing coking temperature was calculated from profile analysis and compared with values obtained from the radial distribution function. The carbonization temperature appeared to have little influence upon the stack height, whereas the layer diameters more than doubled in size between 500° and 1,000° C. These results are comparable to those obtained from other studies of poorer quality cokes.

Jan 1, 1974

By P. A. Richardson

The current Bureau of Mines active list of permissible explosives includes 76 brands. Eleven are gelatinous and the rest are the granular type. The list of permissible blasting devices comprises five Cardox models.

Jan 1, 1970

By G. W. Jones

An important activity of the Bureau of Mines is the promotion of safety in mining and industry. As a part of this program, the Bureau determines the explosion hazards of combustible gases, vapors, and solids and investigates means of controlling and preventing explosions. The limits of inflammability (explosive limits) of combustibles are not only of theoretical but also of practical importance, because many industries at one time or another contend with explosive mixtures of combustible gases or vapors in their manufacturing processes. At present many new organic compounds are being manufactured, transported, and used in huge quantities which a few years ago were only laboratory curiosities.

Jan 1, 1941

By E. G. Davis

A research program to evaluate the use of ceramic die inserts for ferrous diecasting was initiated by the Bureau of Mines at its Tuscaloosa Research Center. Data were compiled from the literature to characterize selected ceramic materials with respect to thermal properties, thermal-shock resistance factors, chemical reactions with molten metals, and processes required to form die components. With this information and a computer model developed for predicting temperature and stress patterns induced in ceramic materials during simulated ferrous diecasting operations, 27 candidate materials were evaluated. After evaluation, only 15 were considered for testing in an apparatus constructed to immerse the ceramic specimens in molten cast iron. Of these, 13 were tested in a modified testing unit in which cast iron was poured onto the specimens. These tests resulted in the selection of three materials for further testing: boron carbonitride (50 pct B4C:5O pct BN), boron nitride-grade M (BN-M, 40 pct BN, 60 pct Si02), and pyrolytic boron nitride (PBN). Tests in a gravity-flow die unit showed that PBN was thermal-shock resistant and could be used in diecasting of ferrous metals.

Jan 1, 1981

By Russell R. Trengove

In order to extend or delimit the known ore reserves adjacent to the Comet Coalition property on the western slope of the Highland Peak Range about 8 airline miles west of Pioche, Nev., the Bureau of Mines undertook an exploration project of diamond drilling. Production figures from this property, formerly known as the Schodde, are not available, but it has been reported that small amounts of rich silver and gold ore were Shipped by wagon to a smelter in the Salt Lake valley during 1900-1910. Small shipments were reported for the period 1915-1927, also. A study of the Pioche District by the Federal Geological Survey in 1942 and 1943 was the basis for the exploration program of the Bureau of Mines in 1947 This program consisted of diamond-drilling three holes. The total footage was 2,967 feet. No. 1 hole was drilled 1,260 feet, a record depth for diamond drilling in the Pioche District. Silver-bearing lead-zinc sulfide ores are found in the Combined Metals limestone, known locally as the C.M. bed, These deposits have been formed by replacement of the limestone that is inclosed in the Pioche shale.

Jan 1, 1949

Southeast Alaska's mining industry has come to life after nearly 50 years of relative dormancy. Commencement of operations of the Greens Creek Mine in 1989 marked a turning point in the industry as the first large scale mining operation in the region since closure of the Alaska-Juneau Mine in 1944. The Greens Creek Mine is now the nation's largest silver producer. Other large scale mining projects are now on the drawing board, including development of the Kensington Mine and reopening the Alaska-Juneau Mine, which could become North America's largest underground gold mine. The region's mining industry includes more than these large scale projects, however. For example, a significant level of mineral exploration occurs each summer in Southeast Alaska. In addition, mining operations in British Columbia and Yukon Territory are generating jobs and income in Southeast Alaska.

Jan 1, 1992

By T. Kessler

As part of a respirable mine-dust research program at the U.S. Bureau of Mines, spark-source mass spectrometry has been used for the semiquantitative determination of trace elements (200 ppm weight or less) in raw coals. In addition, several minor and major elements have been determined using this technique. Sixty-four elements ranging in concentration from 0.01 to 41,000 ppm weight were determined in one anthracite, two mvb, four lvb, and six hvab raw coal samples. The samples represented 10 coal seams located in Pennsylvania, West Virginia, Virginia, Utah, and Colorado.

Jan 1, 1973

By G. V. Sullivan

This report summarizes the results of a preliminary study concerning manganese extraction from low-grade dolomitic materials from the Philipsburg district in Montana by the Dean-Leute ammonium carbamate process. Studies were made to determine the relationship between the variables involved in treating these materials by a roast-leach process and the amount of manganese extracted. The variables studied were the roast temperature, the roast particle size, the molar ratio of NH3 to CO2 in the leach solution, the liquid-solid ratio in leaching, the leach time, and the size of the particles being leached. The roast-leach studies were statistically designed, and the experimental results were evaluated by an analysis of variance.

Jan 1, 1962

By Aarne Visnapuu

Dissociation and vaporization of gold chlorides and bromides were investigated by a static pressure method and by Knudsen cell mass spectrometer. Two distinct chlorine and three distinct bromine pressure-temperature relation-ships were observed for the respective salts. The chlorine pressures are attributed to the dissociation of Au2Cl6 and Au2C12, and the bromine pressures to the dissociation of Au2Br6, Au2Br4, and AU2Br2, These pressure-temperature relationships were used to calculate dissociation pressure equations, enthalpies, and entropies of dissociation for each salt. Mass analysis of the vapors over AU2Cls between 83° and 152° C confirmed the existence of gaseous AU2C16. Ionization potential of this molecule is 11.0±0.1 ev and enthalpy of vaporization is 28.l±2.0 kcal/mole. Mass analysis of the vapors over the gold bromides detected only Bra in the temperature range 15°-150° C.

Jan 1, 1971

By H. M. Cooper

Many analysts have had difficulty in obtaining accurate and consistent determinations of the volatile matter in low-temperature coke when the usual standard method for coal was followed. The tendency is toward too-high results, due to mechanical losses which are extremely difficult to avoid or control. With cokes there also may be an error due to excessive oxidation of the fixed carbon. Much of the earlier experimental work on the volatile-matter determination in coal, such as that of Parr, Fieldner and Davis, and others, has been on the effect of time, temperatures, shape and size of crucibles, method of applying heat, and type of furnace, all of which data has evolved the present A.S. T. M. standard method for volatile matter in coal and coke. It is not the purpose of this investigation to deal directly with the above phases of the procedure, but rather to study some of the factors affecting the results in those types of fuel which give erroneous results due to mechanical losses. This mechanical loss is usually designated as "sparking." There are two kinds of sparks or incandescent particles which may appear: particles of soot from partially condensed carbon from the burning gases, and unburned particles of the material itself which escape. The first type does not affect the accuracy of the volatile matter results, and is therefore negligible. The second type, however, causes appreciable loss and results in showing higher volatile percentages than actually exist.

Jan 1, 1932

Rock mass classification is widely used throughout the underground mining industry—in both coal and hard-rock mines. The technique has been successful because it— • Uses simple measurements to rate rock mass strength. • Helps mine planners to make the best use of geologic information in mine design. • Makes it possible to compare ground control experiences between mines, even when the geologic conditions are very different.

Jul 1, 2007

By H. H. Schrenk, W. P. Yant, P. H. Mautz

"In a study of the chemistry and pathology of chronic benzene poisoning, which was conducted cooperatively by the United. States Bureau of Mines, the Barrett Co., and the producers of benzene, it was necessary to make quantitative determinatious of the abzorption, distribution, and: fate of benzene in the organism. Although methods for determining benzene in relatively large amounts were available no satisfactory method was found for removing and determining the small amounts that are present in the tissues or excretions after exposure to conditions which ultimately cause chronic poisoning. This no doubt accounts for the lack of information in the literature on this particular phase of benzene poisoning.The writers have found in work that will be described in a subsequent publication that the amounts of benzene present in the tissues and excretions under conditions of exposure which produce chronic benzene poisoning arc of the order of a fraction to a few milligrams per 100 grams of tissue. This report describes a method developed and found satisfactory for these determina¬tions.RÉSUMÉ OF PERVIOUS METHODSA method for the determination of benzene in tissue was developed by Joachimoglu. 5 In the Joachimoglu procedure the ground organs are mixed with water and acidified with diluted sulphuzic acid, and the benzene is distilled into a receiver containing carbon tetrachloride. The benzene is nitrated in the carbon tetrachloride, the carbon tetrachloride evaporated, the acid mix¬ture neutralized, and the dinitrobenzene extracted with ether. After removal of the ether the dinitrobeuzene is determined gravimetrically. Joachimoglu reports that this method is about 55 to 60 percent quantitative."

Aug 1, 1935