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By Lester G. Morrell

THE WORLDWIDE economic expansion that has characterized the first 3 years of the 1960's continued through 1964 and was reflected in North America by strength in the industrial economy of the United States, which again was dominant. Advances in production were recorded in virtually all industries, including the mineral industry; 1964 mineral production established a new high, 5.4 percent above the previous peak recorded in 1963. However, the percentage increase in value of North American mineral production was slightly below overall economic growth. For industry in general, consumer demand held firm throughout the year and overall commodity prices averaged 2 percent higher than in 1963. Wages and salary payments also were up. With the single exception of the dock strike in the United States, the year was free of serious labor troubles and unemployment in both Canada and the States was at a low level. Despite the Viet-Nam situation, relatively tranquil international relations contributed to the forward movement of North American business. Total gross national product (GNP) for Canada and United States, in current dollars, was estimated at US$672.2 billion; 6.8 percent above the previous year's figure. Combined national income in 1964 amounted to US$546.9 billion, which was nearly 7.0 percent more than in 1963. In 1964, gains were recorded in each of more than 50 metals, nonmetals, and fuels commodities that comprise the North American output. The greatest category increase was 13 percent in metals, which was in part attributable to the 14 percent rise to a new record in value of iron and steel in United States, a 29 percent higher value of Canadian iron ore and a 57 percent rise in Canadian zinc. Despite a moderate decline in prices of iron ore and iron and steel products, generally favorable markets and rising prices for metallic ores and metals were a stimulant to the metals industry. Nonmetallic materials, with a total value in excess of US$5.25 billion were 7.3 percent higher than in 1963. High levels of highway and building construction and expanding demand for fertilizers and chemicals continued throughout the year. Noteworthy output increases were recorded for lime,

Jan 1, 1966

By J. D. Sargent

Selenium might be described as a paradoxical element, being a metal or a nonmetal, a conductor or nonconductor, amorphous or crystalline, colorant or decolorant, and a hydrogenator or dehydrogenator. Selenium was discovered in 1817 by the Swedish chemist, Berzelius, while studying flue dust from the lead chambers of the sulfuric acid works at Gripsholm, Sweden.

Jan 1, 1954

By Manuel Gomez

The purpose of this study was to evaluate the feasibility of using statistical response surface regression analysis to predict the sulfur and ash distributions and the washability characteristics of coal along a seam in advance of mining. Prediction equations were developed with experimental data from channel, bench, and core samples from the Pittsburgh coal seam in Greene County, Pa. It was not possible, with the available experimental data, to construct mathematical models to predict ash and sulfur concentrations between sample points. In the authors' opinion, however, the good agreement between experimentally determined and predicted values at given sample points demonstrates the usefulness of the method. More input data, such as geologic information, seam characteristics (rock-to-coal ratio), petrographic analysis, and chemical data, would perhaps make it possible to predict sulfur and ash concentrations and washability characteristics between sample points.

Jan 1, 1970

By Donald P. Tuchman

The U.S. Bureau of Mimes is investigating Fourier transform infrared (FTIR) spectroscopy for on- filter quartz analysis of respirable dust. A custom accessory is described for full-face examination of filters utilizing a large-diameter infrared (IR) beam. The accessory positions samples to match diameters with that of the diverging analytical beam. Sample absorbance is then measured. With nonuniform deposition of dust on collection filters being a major issue for such analyses, this approach is the most direct way to accomplish sample area averaging. The approach is unconventional since it utilizes large-beam geometries instead of the usually desired minimized beam dimensions. The issues and problems involved in the analysis of quartz on a filter matrix are discussed. Absorption bands chosen, light-scattering effects, curved baselines, random noise, interference fringes, and possible solutions to technical difficulties are the topics covered. The more significant findings include a 20-pg detection limit for quartz when the custom accessory is used and minimal occurrence of light-scattering effects at low wavenumbers. The custom accessory performance was satisfactory and merits further work. With continued research, an on-filter method for quartz analysis of respirable dusts seems achievable.

Jan 1, 1992

By Dana Reinke, Launa Mallett, Michael J. Brnich

Some segments of the mining industry, especially underground coal, have seen a large influx of inexperienced miners in recent years. It is anticipated that this trend will reach other mining segments over the next 10 years. This paper discusses the training needs of the younger generation of inexperienced workers who have just entered or are soon to enter the mines. Currently, many trainers are of the so-called Baby Boom generation. Can these different age groups learn to communicate across the generation gap? Even trainers who have been highly effective in the past should reassess their training styles and their classroom materials to determine if they are prepared to meet the needs of these new trainees.

Jan 1, 2002

By Earl L. Phillips

The Bureau of Mines conducted laboratory tests on samples of pozzolanic-cement concrete to develop a low-strength backfill. Results show that support costs can be lowered by replacing a portion of the portland cement in mine backfill with pozzolan (fly ash) and lime. Unconfined compression tests on various ratios of fly ash to cement in 84 samples produced compressive-strength curves that can be used to estimate the best backfill mix for any mine.

Jan 1, 1981

By T. T. Campbell

Research conducted by the Bureau of Mines demonstrated the feasibility of preparing columbium and tantalum metals by the application of Kroll-process techniques. Yields in excess of 95 percent were obtained in a modified Kroll-process reduction apparatus constructed from nickel and Inconel.4 Operating conditions during reduction and distillation were determined. Optimum temperatures during sodium reductions ranged from 650° to 750° C and for magnesium from 700° to 800° C with retort pressures ranging from 3 to 7 psig. Undesirable vapor phase reactions occurred when temperatures exceeded 750° C during sodium reductions or 850° C with magnesium. Vacuum distillation at 850° C effectively removed volatile salts and excess reductant from the reduced metals. Calculations based on the results obtained in small scale tests indicate that reaction rates of up to 34 lb/hr could be obtained during columbium reductions and up to 60 lb/hr during tantalum reductions in production scale reac¬tors. The small, laboratory-scale techniques used in this study could be adapted to commercial practice. The reduced powder or sponge metals can be consolidated by conventional arc-melting techniques, and the arc-melted metals can be fabricated into ductile sheet at room temperature. Analyses of arc-melted buttons prepared from Kroll-process tantalum or columbium showed that tantalum of greater than 99.8-percent purity was obtained and that columbium purity exceeded 99.7 percent. A significant purification of the reduced metals occurred when they were consolidated by electron-beam melting, and the purity and ductility of electron-beam-melted Kroll-process tantalum and columbium compared favorably with the commercial metals. After electron-beam melting, the purity of the tantalum exceeded 99.95 percent, and columbium purity was approximately 99.9 percent.

Jan 1, 1962

By W. W. Weller

Heat-capacity measurements of sodium dimolybdate (Na2Mo207) and sodium ditungstate (Na2W207) were conducted over the temperature range from 51° to 298° K. The entropies of the two compounds at 298.15° K were calculated from the heat-capacity values and were used, in conjunction with other entropy data, to evaluate the entropies of formation of the compounds from their constituent elements and oxides.

Jan 1, 1963

By R. H. Sprute

Hydraulic backfill consisting of siliceous mill tailings was successfully dewatered and consolidated by electrokinetics in a field test conducted by the Bureau of Mines at the Star mine, Burke, Idaho. A stope at the 2,000-foot level was filled in such a way that slimes and coarse sand were retained in the scope. Following settlement of solids and decant of surface water, direct current applied between buried electrodes created a firm, dense material in approximately 3 hours. This rapid densification of fine-grained material demonstrated the utility of this method and suggests other applications, particularly in the control of slime deposits that cause serious problems in many deep mines.

Jan 1, 1975

By J. T. May

The Federal Bureau of Mines investigated the extraction of lithium from hectorite-type clay deposits found on the Nevada-Oregon border. Two clay samples were used in the investigation; one contained 0.36 pct Li and the second contained 0.64 pct Li. The purpose of this laboratory-scale research was to determine how these clays responded to different extraction techniques. Extraction techniques investigated were sulfuric acid leach, sulfuric acid bake-water leach, and roast-water leach procedures with cholorides, sulfates, carbonates, and combinations of these reagents. The processing characteristics of the clay samples showed significant variations, and no one technique was effective for both materials. Lithium extractions near 90 pct were achieved during these exploratory studies.

Jan 1, 1980

By M. M. Tilman

The Bureau of Mines conducted research to evaluate superplastic behavior in commercial magnesium-base alloys AZ6IA, ZK60A, ZW3, AZ3IB, ZWI, and an experimental Mg-12 pct Al alloy. Strain-rate sensitivity indices (m-values), maximum elongations, and effects of superplastic elongation on tensile properties were determined on fine-grained sheet. Inert-gas-pressure hemisphere-forming tests were conducted on selected sheet stock of the five alloys. Formability trials on AZ31B alloy sheet were conducted on industrial equipment for comparison with commercial superplastic forming of Zn-AI alloy. Closed-die-forming tests were performed on extruded ZK60A rod. All alloys exhibited well over 100-pct elongation, indicating superplasticity, at temperatures and strain rates near the maximum m-values. Tensile properties were generally reduced following 100-pct superplastic elongation, but not to an extent that would preclude use of the commercial alloys in the superplastically deformed condition. The potential for industrial superplastic forming of AZ31B sheet was indicated by hemisphere forming in the laboratory and substantiated in industrial forming trials.

Jan 1, 1982

By Curtis H. Elder

In studies conducted by the Bureau of Mines, two test areas were hydraulically stimulated and exposed by mining: One in the Pittsburgh coalbed at the Vesta No. 5 mine, Washington County, Pa.; and one in the Illinois No. 6 coalbed at the Inland mine, Jefferson County, Ill. Induced fractures were contained totally within the coalbed with no adverse effect on the stability of associated rock strata. Induced fractures were vertical and were propagated normal to the direction of least residual tectonic stress. Gas production was increased fivefold to twentyfold by hydraulic stimulation.

Jan 1, 1977

By J. T. Schimmel

The purpose of this investigation was to obtain complete information on some of the uses of a 24-inch-diameter auger in the underground mining of pitching anthracite beds. The auger was placed in operation early in 1958 to drive ventilation connections between coal gangways driven by a continuous miner. Although designed to drill rise holes only, it was used also to drill dip holes. The latter holes were drill id from an adjacent gangway to avoid interference between the auger and the continuous miner. These holes established immediate ventilation returns when intersected by the continuous miner. Bureau participation in the project covered 361 working days. The auger was used on 288 shifts, usually one 7-hour shift per day, and drilled 3,246 feet, of which 493 feet were reamed. The longest hole was 87 feet; hence the maximum drilling depth of the machine (rated at 100 feet) was not required. Holes drilled normal to the strike of the bed ranged from 30 to 66 feet deep, averaging 45 feet. The continuous miner drove gangways on 575 shifts. Thus, the auger worked one shift for each two worked by the continuous miner and was used on less than 80 percent of the workdays. The auger drove 24-inch holes 10 times faster than the larger, conventional openings could have been driven by usual mining methods and exceeded the workload for which it was purchased. Augering eliminates exposure to the hazards encountered in driving chute-work by conventional methods and provides adequate circular ventilation openings, which are strong in self support and are adaptable to reaming when required. With alterations, the auger may have limited use as a production machine in thin-bed pitch mining but cannot compete with established methods of thick-bed pitch mining.

Jan 1, 1962

By W. D. Bensema, J. W. Adams, W. W. Scott, H. Dobroski

Measurements of the absolute value of electromagnetic noise and attenuation along a hoist rope were made in an operating hard-rock mine, Lucky Friday Mine, located near Wallace, Idaho. Spectra of electromagnetic noise generated by various pieces of equipment, spectra of specific noise signals at various depths, and noise and attenuation on the 4250 foot (1295 meter) hoist, were measured. Three techniques were used to make the measurements. First, noise was measured over the en- tire electromagnetic spectrum of interest for brief time periods. Data were recorded using broadband analog magnetic tape for later transformation to spectral plots. Second, noise amplitudes were recorded at several discrete frequencies for a sufficient amount of time to provide data for amplitude probability distributions. A third technique gave attenuation data through the direct measurement of field strength at various depths. The specific measured results are given in a number of spectral plots, amplitude probability distribution plots and amplitude curves as a function of depth.

Jan 10, 1974

By R. J. Hundhausen

The continued worldwide shortage and strategic value of nickel place great importance upon the continued development and exploitation of new sources of nickel in the United States, The deposits of nickel-bearing minerals in Oregon and Washington have attracted considerable attention, particularly since the Hanna Development Co. has engaged in development work aimed at producing ferronickel from the Nickel Mountain deposit, near Riddle, Douglas County, Greg. The Red Flats nickel deposit in Curry County, Oreg., was first examined by the Bureau of Mines in dune 1945, but it was not until 1952 that the deposit was drilled and sampled. In 1953, a 15-ton sample of Red Flats material was procured and subjected to continuous smelting tests in the Bureau's Northwest Electrodevelopment Laboratory, Albany, Greg.

Jan 1, 1954

Lower the respirable dust exposure of longwall shearer operators by keeping the dust cloud confined to the face. Approach Change the location of face-side machine cooling, water sprays. How It Works The dust breathed by the longwall shearer operator is usually produced by the shearer itself. The dust cloud originates at the face, and the exposure of the operator depends largely on how quickly this cloud spreads into the walkway. Water sprays on the shearer body can have a large effect on dust cloud spreading. Results to date indicate that sprays can help confine the dust cloud to the face if they are carefully placed. Otherwise they can make dust levels far worse. The worst offenders are often face-side sprays used to discharge cooling water from the cooling jackets of the shearer motors. These face-side sprays set up an air circulation pattern as illustrated in the drawing. Air induced by the sprays to flow towards the face, raises the air pressure in front of the face, which causes the air flow to turn and then move back over the shearer, bringing dust with it into the walkway.

Jan 1, 1981

By August J. Kwitowski

This Bureau of Mines report describes how the reinforcement mechanisms of untensioned, full-column resin bolts were determined during one underground study. Both axial and transverse shear loadings were identified for two instrumented resin bolts that replaced standard resin bolts in an opera-ting room-and-pillar mining section. The strain responses of resin bolt steel cores to local axial and transverse shear loadings are described. This information was obtained from laboratory testing of resin bolts installations; it was also used to analyze the data from the underground test.

Jan 1, 1980

By F. P. Haver

The Bureau of Mines developed a process to extract about 90 percent of the sulfur from molybdenite flotation concentrate by compacting the concentrate with one-quarter of its weight of aluminum powder, heating it at 800° C for 30 minutes, and then allowing the product to react with water. This thermite reduction yields an impure molybdenum alloy plus aluminum sulfide. The latter readily hydrolyzes, to yield pure hydrogen sulfide which can be converted to elemental sulfur by the Claus process. At least 95 percent of the molybdenum can be subsequently recovered as 99.95-percent-pure molybdic oxide.

Jan 1, 1968

By Nicholas Kyriazi, John P. Shubilla

The National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, has undertaken a study to determine how well self-contained self-rescuers (SCSRs), deployed in accordance with Federal regulations (30 CFR 75.1714), hold up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSRs in the seventh phase of testing from May 1999 to August 2000. The SCSRs were tested on human subjects and on a breathing and metabolic simulator. The results indicate that most of the apparatus, if they pass their approved inspection criteria, perform satisfactorily. The deployed CSE SR-100s, however, exhibited significantly higher inhaled carbon dioxide (CO2) levels than new units, as they did in the previous two phases. Several Draeger OXY K-Pluses that rattled when shaken were found to have potassium superoxide (KO2) particles throughout the breathing circuit, including the mouthpiece. Draeger investigated the problem and developed a shake test to detect damaged units. The durations of new Ocenco M-20s were statistically significantly longer than those of deployed units, although only by 2 min.

Jan 3, 2002

By James A. West

COUNTRIES of the Near East, with the world's largest and insist prolific petroleum resources, produced nearly 277 percent of the world's estimated total output of crude& oil in 1964 and accounted for about 60 percent of world exports of this commodity. Although petroleum largely dominated the mineral industry of tine area, production of antimony, chromium, copper, mercury, boron, potash, and phosphate rock was of world significance. Production of crude oil in Near East countries reached a record high of 7,520,000 barrels per day in 1964, an increase of nearly 11 percent over that of 1963. Kuwait maintained its position as the leading producer, accounting for almost 28 percent of the area's output. Saudi Arabia, Iran, and Iraq followed with 22.5, 22.2, and 16.5 percent of total area output, respectively. Despite record production, the Near East, proved crude oil reserve remained in excess of 211 billion barrels, or more than two-thirds of the estimated world proved crude oil reserve.

Jan 1, 1966