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By J. A. Holmes, EDWARD C. FRANKLIN, RALPH A. GOULD

The commission may be permitted to express its earnest hope that the litigation which comes to an end with the findings and recom- mendations herein set forth will be considered by both parties to the action as definitely and equitably decided. The commission trusts that its work will show the value of the commission form of settlement and that its work will serve as a prece- dent to be followed in disputes relative to technical subjects. If the work of the commission is productive of a tendency on the part of technical litigants to avoid the use of the courts for the settlement of disputes it will not have been done in vain. Such tendency will surely grow and ultimately such differences will be arbitrated by technically trained men without recourse to the courts of law. Appended to the report of the findings of the commission are to be found the detailed reports covering the several lines of inquiry and investigation carried on by the commission and upon which its findings are based, and also a detailed statement of the fiscal affairs of the commission. A word of explanation is necessary in regard to the fiscal statement. While each party to the litigation has agreed to bear one-half of the expense of the investigations of the commission, it will be noted that the Selby Smelting & Lead Co. is credited with $21,000, while Solano County is credited with but $6,000. In order that the investigations of the commission might go forward without interruption the Selby Smelting & Lead Co. has generously supplied funds at the times they were needed. This assistance has been

Jan 1, 1915

By Robert H. Peters

Several significant problems associated with employee turnover among underground miners are described in this Bureau of Mines report. Although a vast amount of research has been conducted on turnover among employees in nonmining industries, there has never been an attempt to empirically investigate the causes of turnover among underground miners. This report presents the results of empirical research on employee turnover in other industries and describes and critiques the research methods that have been used to investigate turnover. Using the findings on employee turnover in other industries and known data about miners and the mining industry, a conceptual model of the factors that cause turnover among miners was generated. This model, which is expected to provide a basis for later empirical studies, is presented. Several recommendations for controlling miner turnover are also presented.

Jan 1, 1986

By C. J. H. Brest van Kempen

The objective of this contract was to provide thrust and torque control and visual output torque readout systems to an existing mine roof bolting machine and to test the consistency of torques obtained under actual field conditions. A Lee Norse TD1 roof bolter was modified by adding a simple torque sensing device to the drill rotation mechanism and a pneumatic logic control circuit that measures torque and controls the hydraulic circuit to the rotation motor. The modification controls and indicates the final installation torque of mine roof bolts. A total of over 5,000 mechanical roof bolts were installed in an operating coal mine. The installed torque of these bolts were within an error band (standard deviation) of 8%.

Jan 1, 1978

By Richard V. Ageton, Harry E. Tufft, E. A. Holbrook

When an underground excavation is made, the rock surrounding the sides and top of the opening is deprived of its natural support and tends to fall. Whenever caving takes place, the time and extent of the caving depend on the character and condition of the rock. In strong homogenous rock, such as solid granite, even a large chamber may stand indefinitely, whereas a soft material, such as clay or a loose material like unconsolidated sand, falls immediately if not supported. Weaknesses in the rocks induced by structural features, such as joints, :fissures, bedding and cleavage planes, and fractures produced by blasting, will cause the falling of insecure blocks or slabs unless means are provided to support these in place. In an unsupported mine opening, as a tunnel, the first slight settling or adjusting movement of the rocks (the "initial creep" or "set") is caused by the great weight of overlying material pressing down the rock masses above and around the roof and sides of the opening until they key together in roughly the form of an arch. The rock, after it has adjusted itself to this shape, becomes. selfsupporting. Timbering is necessa.ry in all mining only to support, therefore, those comparatively small blocks or pieces of rock which tend to loosen from the top and sides of the opening during or after the formation 'of the natural rock arch, and which lie between this natural rock arch and the opening. This statement, of course, has its limitations. For example; a layer of strong rock, like limestone, may act as a beam; then only the material under the limestone will need support. Timbering is not, as is commonly supposed by the layman, used to supp!ort the huge mass of rock between the back (roof) of an underground opening and the surface. It would be impossible to place enough timbers in a:ny underground opening to support such a mass. This fact is not'·perceived by all miners.

Jan 1, 1923

The U.S. Bureau of Mines, Department of Labor, and United States National Committee of the CIE hosted the TC4.10 Mine Lighting Committee Meeting and Second International CIE Mine Lighting conference at the MSHA Academy in Beckley, WV from October 12-16, 1981. This was the first time the meeting and conference had been held in the United States. The TC4.10 Mine Lighting Committee, chaired by Dr. Adam Peretiatkowicz of Poland, was attended by 15 committee members and six guests representing eight countries. Discussion during the meeting covered mine lighting instrumentation, open cast (surface mine) lighting, and lighting sources. The committee also reviewed a draft of proposed lighting terminology and suggested changes to make the definitions more acceptable to representatives of the nations present. The mine-lighting conference featured 20 papers presented by 18 speakers representing six countries. The papers covered all phases of mine lighting, including research, hardware development and application, personnel acceptance, and requirements for system maintenance. The conference attracted 126 attendees and also included displays by eight lighting hardware manufacturers and four mining machine manufacturers. Papers from the conference are being published by the Government Printing office, with copies presented to the conference attendees. Copies will be available to others interested through the NTIS. During the course of the TC4.10 meetings and conference, committee members toured three mining equipment assembly plants, and six of the foreign representatives visited a longwall installation in an underground mine. Planning and administrative services for the meeting and conference were handled by Bituminous Coal Research, Inc., under USBM Contract H0318038.

Jan 1, 1982

By L. B. Pankratz

High-temperature heat contents were measured for two praseodymium oxides and three terbium oxides. There were: Pr2O3 (298° to 1,600° K), PrO1.833 (298° to 1,050° K), Tb2O3 (298° to 1,600° K), TbO1.719 (298° to 880° K), and TbO1.812 (298° to 850° K). With the exception of PrOl.833, all results were regular. PrO1.833 had a small thermal anomaly at 760° K with an extra absorption of 380 cal/mole. The measured heat content values, tabulated smooth heat contents, and entropy increments are reported. Heat content equations were derived.

Jan 1, 1966

By Larry A. Haas

The U.S. Bureau of Mines is investigating ways of enhancing the high-temperature softening-melting (HTSM) properties of domestic taconite pellets. These properties, which are important for determining the performance of pellets in blast furnaces, include pellet bed contraction, pressure drop, S-value (area under the pressure-temperature curve), and softening and metal-slag drainout temperatures. Experiments showed that HTSM properties were related to the physiochemical properties (fired strengths and reducibilities) of pellets containing different levels of limestone and dolomite flux. Flux additions resulted in slightly lower green and fired pellet strengths, but improved metallurgical properties, such as reducibility. The influence of reduction conditions on HTSM properties was evaluated by varying the pellet metallization starting temperature and the carbon monoxide content of the CO-N2 gas mixture. HTSM property change was more sensitive to flux addition levels when metallization was initiated at 1,100° C with 20 pct CO in the gas stream. The S-value and the metal-slag drainout temperature were found to be the best criteria for characterizing HTSM properties. The optimum flux addition level was about 8 pct (4 pct dolomite, 4 pct limestone) or a basicity of about 1. At higher flux levels, a higher metal-slag drainout temperature was obtained.

Jan 1, 2010

By Albert E. Schreck

[THE COMPOUNDS of strontium were confused with those of barium until 1790, when A. Crawford discovered that the mineral strontianite, long believed to be a barium mineral, was a compound of a new element. This discovery was confirmed 2 years later by I. C. Hope. The mineral was named strontianite because it was found near the town of Strontian in Argyllshire, Scotland. In 1808 Sir Humphrey Davy isolated strontium metal by the electrolysis of fused chlorides. Celestite (strontium sulfate) and strontianite (strontium carbonate) are the principal strontium minerals. Because of its more widespread occurrence, celestite is more important commercially.]

Jan 1, 1959

By B. K. Shibler, W. G. Sandell, G. M. Potter, H. D. Snedden

"INTRODUCTION During the course of the investigation of the occurrence of manganese deposits in the western United States, examining 'engineers of the Bureau of Mines collected samples from seven manganese properties in Grand and beery Counties, Utah. These were supplemented by five samples submitted by property owners. Since all of the ores were too low-grade for use in producing ferromanganese for steel manufacture, some means of beneficiation was required to produce marketable concentrates, and metallurgical studies were made on each of the samples.Most of the ores Investigated are similar in one respect: At least part of the 'manganese oxide areas contains minute inclusions of gangue. This occurrence materially enhances the complexity of the ore, partly by .increasing the complexity of mineral association, but largely through making manganese-quartz liberation more difficult. In such ores, there is a marked tendency for the manganese minerals to be retained as shells or coatings on the surfaces of quartz particles when crushed. Particles of this type represent considerable loss of manganese in tailing, if gravity-concentration methods are employed, or tend to' float, thus carrying an appreciable quantity of gangue into the concentrate, if treated by flotation.Plus 48-percent manganese sinters were made from some of the ores tested, but, in general, intimate association of manganese minerals with silica limited the degree of beneficiation attainable."

Dec 1, 1947

By John R. McWilliams

This is one of a series of reports being published by the Bureau of Mines on mining methods and costs at various mines throughout the United States. Including the Holden mine in this series is particularly appropriate at this time. The mine was operated on a low-cost, large-scale production basis to compensate for low-grade ore. Even with the best conditions and the most efficient methods, the margin of profit was small. Under the present situation of rising costs and lowering metal prices, the profit margin vanished. On June 28, 1957, the mine operations ceased; therefore, this report can review the entire life span of the mine.

Jan 1, 1958

By Jack L. Woodward

The evolution of surface mining equipment has resulted in larger, faster haulage units, loaders, etc., resulting in increased demands on steering technology. Careful analysis of these systems was warranted to determine if steering-related safety problems have been introduced. The objectives of this program were to: 1. Define the generic types of steering systems being used on mobile mining equipment used in surface mining operations. 2. Gather information on steering-related accidents in mining operations. 3. Assess the need for initiating government-sponsored research into steering system technology. A comprehensive literature survey was conducted concurrent with extensive contacts with mining operations, mining equipment manufacturers, steering system component manufacturers, and government agencies. A Technical Evaluation Group composed of representatives from the above organizations was formed to review the data gathered. It was concluded that the steering systems in use on surface mining equipment are reliable and do not present a safety problem. The Society of Automotive Engineers, Inc. is active in pre-paring voluntary consensus standards to assure that the minimum levels of performance are defined for industry.

Jan 1, 1979

By Jack E. Fraley

In this Bureau of Mines study, sealants containing mineral wool, cement, etc, were sprayed through dry-process equipment that propels dry material pneumatically to the water-adding nozzle. Advantages over slurry applications include no mixing, no extensive cleanup, and freedom from hardened cement in equipment should power be lost. Sealants with large mineral wool nodules (>l-inch) were sprayable at rates to 900 square feet per hour for 1/2-inch thickness with little dust and smooth material flow through equipment, but they were weak for mine use, Materials containing small wool nodules (1/4-inch) were stronger but tended to plug lines because the nodules were inadequately separated in the shredder. Increasing the dedusting oil also increased line plugging by holding the nodules together in larger lumps. Best results were obtained using a 3/4-inch-nodule wool with cement binder, which provided both smooth flow through the machine and adequate strength.

Jan 1, 1977

By John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By W. D. Striffler

Land disturbed by surface mining in Colorado and other western states has increased substantially over the past several years and is likely to increase even more in the future. This study was initiated to provide basic information on hydrologic and erosional characteristics of regraded coal spoils in Colorado as an aid for planning future reclamation activities. Eleven of twenty-one surface mines licensed in Colorado were sampled during the summer of 1980 and 1981. Mines not sampled included mines which had not progressed to the point that reclamation had begun, and mines where operators denied permission to sample. All coal regions were sampled with the exception of the San Juan Coal Field. Physical and hydrologic characteristics of regraded coal spoils in Colorado were determined using standard field and laboratory procedures. Field sampling included characterization of sites (slope, vegetation density, proportion of surface rock, bare soil, etc.) and infiltration measurements using a l-meter square drop former raining on a 1/2 square meter rectangular plot frame. Core samples collected in the field were analyzed for saturated hydraulic conductivity, bulk density, organic matter, moisture retention and texture. The erosion potential of each site was determined using the Universal Soil Loss Equation (USLE). Results of the sampling indicate that infiltration rates vary widely both within and between sites. However, definite trends with respect to coal fields are apparent. For example, the Green River (Yampa) coal region had a wide range of sampled infiltration rates (1.2 to 5.1 cm/hr). However, most of the sites clustered towards the low end of the range. The North Park (Marr Strip) also was rated at the low end of the infiltration range (2.0 to 3.0 cm/hr). Average infiltration rates for the Canon City and Uinta Coal Regions were at the high end of the range (4.9 to 5.5 cm/hr). Multiple correlation analysis of infiltration rates vs. site characteristics showed that infiltration rates were most closely correlated with the depth of wetting, the amount of mulch cover, and site slope. The depth of wetting was highly correlated with the depth of the topsoil and the bulk density of the spoil. In general, the topsoil at all sites appeared to be highly permeable to water intake but once saturated, subsequent infiltration depended upon characteristics of the underlying spoil. Vegetation cover affected infiltration on individual mine sites but was not as pronounced as topsoil characteristics or mulch. Erodibility of topsoil and spoils, as determined by Wischmeier's "K" factor, ranged from 1.34 to 0.56 tonnes/ha. (topsoil) and 1.25 to 0.66 tonnes/ha. (spoils). Definite trends in erodibility are evident. The Green River (Yampa) Coal Region displayed consistently higher erodibilities (1.34 to 0.75 tonnes/ha.) than other coal fields (0.72 to 0.56 tonnes/ha). Lowest erodibilities were observed in the Uinta, North Park, and Raton Mesa Coal Regions (0.56 to 0.62 tonnes/ha). Erodibilities of underlying spoils showed similar trends as the topsoils. Erosion potential (the product of soil erodibility and rainfall erosivity) was detennined using calculated ?K? factors and rainfall erosivities (R) taken from Clyde (1976). Results show that the Delagua coal field, Raton Mesa Coal Region had the greatest erosion potential due to the high rainfall energies in the region, while the North Park and Uinta Coal Regions had the lowest potential erosion.

Jan 1, 1981

By Stephenson. E. L.

"INTRODUCTION In the spring of 1942 a series of magnetometer surveys on deposits of black sand underlying Pleistocene raised marine terraces along the coast of southwestern Oregon was nada by the Division of Geophysical Exploration of the Federal Bureau of Mines in cooperation with the Oregon Department of Geology and Mineral Industries. A few preliminary tests had been made in the same area in May 1940 and December 1941.The sands contain fine gold and metals of the platinum group, and, beginning in 1852, extensive, but spasmodic mining and exploration have been done for these precious metals. There are many old placer, mines and prospects, although for the most part the yield of the metals has been small. The sands also contain other minerals of potential value, including ilmenite, magnetite, garnet, zircon, and particularly chromite, and the wartime demand for domestic chromite resulted in extensive testing and development of the known deposits. The purpose of the magnetometer surveys was to determine the efficacy of, magnetic methods in tracing and outlining these known deposits and in prospecting for new ones. The field work was done between March 17 and May 29, 1942, by the author assisted by W.W. Paulsen of the Oregon Department of Geology and Mineral Industries."

Jun 1, 1945

By Dennis R. Dolinar

Physical property tests were conducted on drill core from three exploratory holes on the Naval Oil Shale Reserve near Anvil Points, Colo. Data and regression analysis curves are presented. Data obtained above the Mahogany zone were used to estimate the potential zone of surface effects from under-ground mining. Single specimen testing was primarily used to obtain Mohr's envelope and subsequent rock properties. The technique is shown to provide satisfactory results for this rock type with a significant reduction of core preparation and testing time.

Jan 1, 1981

By H. E. Heide

"Before the war, the United States was the world’s leading consumer of tin, the industrial applications of which had become widespread. Domestic production was negligible, and requirements were met almost entirely by imports, principally from British Malaya, United Kingdom and China. Average annual imports for the years 1925-1929 amounted to 78,009 long tons.With the advent of war in Europe and signing of the Japanese-German pact, it was realized that foreign sources of supplies were threatened, and steps were taken by Congress to forestall critical shortages of tin and other minerals. These steps in regard to tin included stock-piling, improving reclamation and conservation, increasing South American production, constructing a smelter in the United States for treatment of tin, ores, and intensifying the search for domestic tin deposits. Annual imports were raised to 140,873 long tons by 1941. On 1945, annual imports had shrunk to 37,675 long tons and consumption had been reduced to 52,100 tons of primary and secondary tin but not tin content of scrap alloy.The Strategic Minerals Act, passed by the Congress in 1939, authorized the investigation of domestic tin deposits.As Alaska had supplied virtually all of the domestic output of tin, an investigation of Alaska deposits was undertaken in 1940 and 1941 by J. B. Mertie, Jr., and Robert R. Coats of the Geological Survey.The Lost River lode tin mine on the Seward Peninsula was examined by H. E. Heide of the Bureau of Mines in 1942. Possibilities for developing a significant amount of tin appeared favorable, and exploration of the ore bodies was started in August 1942."

Jul 1, 1946

By Abrasive Materials

Table 1.-Salient abrasive statistics in the United States [ ]

Jan 1, 1967

By Daniel T. Rogers

The Bureau of Mines, in its alumina miniplant project to investigate alumina recovery from domestic, non bauxitic ores, has conducted research on the use of a hydrochloric acid leaching, gas sparging crystallization technology. An important element of this research is the efficient separation of undissolved, siliceous residue from AICI3 -bearing leach liquors by continuous, horizontal, countercurrent vacuum belt filtration. In an effort to calculate material balances quickly and to predict material balances based on different belt filtration configurations, the perfect-mixing-cells-in-series model (PMCS) for calculating material balances around belt filters was used. Because of the porous nature of the solids, the model produced erroneous material balances. Therefore a reliable model, the shrinking voids model, was developed postulating the presence of an unwashable voids liquor volume that decreases with decreasing liquor AICI3 concentration. This volume decrease postulation is equivalent to assuming that dilute liquors flow more freely, causing more voids liquor volume to become washable. Least-squares based computer programs are provided, which are useful not only in producing material balances from plant data but also in predicting balances for untested configurations using the same feed materials.

Jan 1, 1982

By Thomas L. Starks

Surface soil/spoil Samples (0-10 cm) from experimental test sites in western North Dakota were aseptically collected during August 1975 and each month (May through September) during 1076 and 1977. Selected samples were Cultured in a defined inorganic medium and after six weeks the algae were identified. Chlorophyll u content of the soil/spoil was used as a measure of the algal abundance. Soil physical-chemical properties, species variety and abundance were statistically analyzed. All test sites revealed distinct soil algal communities and demonstrated a successional trend as evidenced by significant increase, in species variety and bionmass over time. Some soil factors, calcium, copper, and phosphorus affected species variety and abundance at more than one situ. Others were important at specific sites; silicon and aluminum at the South Beulah test site; manganese sodium and zinc at the North Beulah test site No. 1 and boron, cadmium and magnesium at the North Beulah test site No. 2. Topsoiled areas had higher species varieties and abundances when compared with control areas, as did plots treated with amendments such as leonardite and fertilizer Generally.

Jan 1, 1982