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The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment: including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that arc recommended in this document, but all of the panic bars are characteristically of the "fire door" type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they arc required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in "Guidelines for the Design and Installation of Devices for Deenergization of Self-Propelled Electric Face Equipment/Automatic Emergency Brakes" by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel al the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By R. T. MacMillan

A number of chemical techniques have been applied to manganese ores from three areas of Aroostook County, Maine. Although large tonnages of these ores have been proved, they are low grade, and their exploitation has awaited a suitable beneficiation scheme. As conventional ore-dressing methods had failed to yield satisfactory results, attention was turned to chemical procedures. Leaching with dilute (7-percent) H2S04 extracted over 90 percent of the manganese from ore of the Dudley farm area, consuming 3.8 pounds of acid per pound of manganese extracted. Ores from the Littleton Ridge and Maple Mountain-Hovey Mountain areas were less amenable to this treatment, yielding approximately 80 and 60 percent of their Mn content, respectively. To increase the percentage extraction of manganese in the latter two ores, a number of factors were varied, including (1) acid concentration in the extracting solution, (2) ratio of acid to Mn in the slurry, and (3) preliminary heat treatment of the ore with a reducing agent. Other acids, including HNO3, HC1, and H2SO3, were tried also; however, no significant improvements in the Mn leached from Maple Mountain-Hovey Mountain ore were made. The manganese extraction of Littleton Ridge ore was raised to 90 percent by providing 9 to 11 pounds of HNO3 per pound of Mn in the ore.

Jan 1, 1954

By Michael M. Hamilton

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied a 37,542-acre portion of the 57,002-acre Riordan?s Well Wilderness Study Area (NV-040-166) in order to evaluate its mineral resources. The area studied is located in Nye County, NV, about 60 miles southwest of Ely, NV. Subeconomic mineral resources of limestone and sand and gravel were identified in the study area. The Troy and Irwin mining districts, 4 miles to the west, were active between 1868 and 1963, producing small amounts of gold, silver, lead, and tungsten from mines well outside the study area. Except for minor prospecting activity, most mining activity in the study area has been since 1980, consisting of claim locations and geochemical surveys.

Jan 1, 1987

By W. F. Faragher

The principal equipment in the catalyst plants at Ludwigshafen-Oppau was inspected and is presented in the form of flow sheets for the manufacture of four of the principal catalysts. The equipment is in many cases of special design rather than stock items that was built by the company and modified in the coarse of the growth of the high-pressure synthesis of hydrocarbons in Germany. It is believed that if the manufacture of catalysts were to be undertaken elsewhere, the selection of equipment for the operations involved could be made successfully from the guidance furnished by this rather general report. Five additional catalysts are described, also. II. CATALYST 5058 FROM FRESH TUNGSTIC ACID In a supply tank of about 2,000 liters capacity, 500 kg. of tungstic acid (W03.H2O) that contains about 92-93 percent of W03 is dissolved at 60-70° C. in 1,500 liters of mother liquor. The solution is-effected by stirring for about 1-1/2 hours. The mother liquor is obtained from a previous, lot of catalyst and is first adjusted to a concentration of 13 percent 1H3 by passing in gaseous ammonia. The solution is allowed to stand without stirring for 1 hour, then is pumped into the saturating vessel through a cloth filter (three-quarters hr. to one hr.). The saturator is purged with H2S and thereafter the solution, which has been cooled to about 75° C., is heated in an atmosphere of hydrogen sulfide with stirring to about 70° C. This charge is slowly cooled to 50°, and then more rapidly to about 20° C. (time of cooling 6-7 hours).

Jan 1, 1946

By J. Roger Loebenstein

Small amounts of arsenic trioxide were shipped in 1988 from remaining stocks at ASARCO Incorporated's closed plant at Tacoma, WA. Imports of arsenic trioxide were at about the same level in 1988 as in the previous year. Legislation and Government Programs The Occupational Safety and Health Administration (OSHA) levied a $1.6 million fine against Asarco for exposing its workers at its East Helena lead smelter in Helena, MT, to unacceptably high levels of lead and arsenic. The bulk of the fine was for violations of a respiratory protection program. The same smelter and its environs has been listed as a Superfund toxic-waste site by the Environmental Protection Agency (EPA). Tests had shown high levels of lead, cadmium, and arsenic in the soil near the smelter. EPA planned to extend the cleanup to areas within the town of East Helena because high levels of arsenic had been found in shallow test wells outside the smelter site. Federal and State health officials have warned residents living in the vicinity of East Helena to avoid eating certain home-grown vegetables because of high concentrations of heavy metals.2

Jan 1, 1990

By Walter E. Lewis

A mothod of cutting St. Poter sandstono by streams of water under pressuro from nozzles and pumping the resulting, sand to the surface has roduced the cost of storm-sowor construction in the Minneapolis-St. Paul aroa. The hydraulic tunneling method, has boon in uso since 1934, and it is adaptable only to the lower part of tho St. Potor, sandstone, which lios within or just abovo the ground-wator levol. Tho upper part of the formation, immediately bolow tho Plattoville limestone, 18 comonted and camot bo mined by hydraulic mothods. The tunnel oporation observed in this instance is a main storm sowor starting at tho Mississippi Rivor below the 10th Avenuo SE bridge and will be drivon 6,000 foot at a grado of 1 foot por thousand undor the city of Minneapolis to Konnody and Arthur Stroots NE. A lateral storm sowor, which branchos from the main sovor at 8th Street SE, will oxtond from 10th Avonuo SE to 15th Avonuc SE. Tho tunnele are being drivon with the floor approximately at ground-wator lovol. All waters ontoring the main storm sower vill drain into the Mississippi Rivor. Tho main storm sewer cross soction is excavated to a roughly hox- agonal shapo 10 foot high by 10 foot wido at the contor. The upper half of the tunnol soction is solidly lined with either timber or stool. After all oxcavation is completed, the tunnel will be finished with a concrete circular lining 8 feet in inside diameter. The lateral storm sewer is excavated to a 5-1/2-foot by 7-1/2-foot section and will event- ually be finished with concrete to a modified horseshoe-shaped section 6 feet by 4 feet. Where the back or walls are considered unsafe during excavation, the upper half of the tunnel is lined solidly with timber. The equipment used by the Sower Division, City of Minneapolis, has been selected to meet a number of applications in storm-sewer work with diversified usage in mind. The sand pumps used on this job are rubber-lined, designed to work against a head of 100 foet. Either 4-inch or 6-inch diameter suction and discharge openings may be used. Other equipment, such as pipe, mine rail, flexible hoses, compressors, and general surface shop equipment, is drawn from a contral warohouse. It may be either new or used, depending on what is available at the warehouse. Much of the pipe and mine rail has been used for many years on several different tunnol jobs.

Jul 1, 1950

By C. M. Flynn

The solubilities of sideronatrite [Na2Fe(OH)(SO4)2?3H20] and ferrinatrite [Na3Fe(SO4),&apos;3H2O] were determined by the Bureau of Mines in the Na2SO4-Fe2O3-H2SO4-H20 system at 25°, 40°, 60°, and 90° C. The solution compositions investigated ranged from Na+-Fe&apos;+ mol ratios of 0.5 to >100 (Na2SO4 saturation) and H+ -SO4 2-mol ratios of 0 to 1. O. The results are presented in the form of contour plots. The solubilities were determined by seeding supersaturated solutions of known composition with the specified solid phase to precipitate a substantial amount of solid. Water was then added in small portions to the solution until the last portion of the solid dissolved. Equilibration times at 25°, 40°, 60°, and 90° C were 2 days, 1 day, 8 to 16 h, and 2 to 4 h, respectively. The accuracy of the solubility data is estimated to be 1 to 2 pet. Low iron solubilities of <0.36 pct Fe2(SO4)&apos;, or 1 g Fe/kg solution, were obtained in solutions containing at least 8 pet Na2SO4 in the absence of H2SO4 or a total of at least 36 to 38 pet Na2SO4 + H2SO4 at high acidity. The filterability and density of sideronatrite and ferrinatrite in comparison with other iron compounds are reported. These compounds are suitable vehicles for iron removal in Na2SO4-rieh solutions. Additional solubility data on the Na2SO4-H2SO4-H20 system were also obtained.

Jan 1, 1987

By Doris M. Hyde

The Bahama&apos;s petroleum-dominated minerals sector constricted again in 1985. The declines were mostly the result of a soft market demand for crude oil and petroleum products. In early 1984, it was a growing unprofitability that prompted Charter Oil Co. to cease using the 350,000-barrel-per-day Bahamas Oil Refining Co. facility that it jointly owns with Chevron Oil Bahamas Ltd. After midyear 1985, because of poor petroleum economics, Chevron announced it would close the refinery, leaving only a maintenance crew. In 1984, the refinery exported less than 26 million barrels of petroleum products. Chevron&apos;s throughput was reported as averaging about 8,000 barrels per day at the time of the announcement. The crude oil transshipment terminal also registered declining activity and financial losses in 1984 and 1985. Transshipments of petroleum in 1985 amounted to about 100,000 barrels per day, one-half as much as in 1982.

Jan 1, 1987

By R. A. Cattell

Every finding of the year&apos;s work, obtained under stress to meet present objectives, contributed to postwar needs, because the very nature and constitution of petroleum and natural gas require that research be conducted along the same general lines whether the results are applied in peace or war. More than 40 reports were submitted to the Petroleum Administration for War and others concerned with (1) evaluation of crude oils to determine their content of aviation-gasoline base stock, (2) evaluation of base stocks for blending with high-octane, synthetically manufactured components, (3) analyses of naphthas to determine their content of various types of hydro-carbons, such as benzene and toluene, and (4) the improvement of quality of marginal base stocks to meet future requirements of aviation gasoline. This upgrading of marginal stocks is being attained by selective distillation and chemical and catalytic removal of sulfur compounds. Asphalts were studied with respect to the characteristics of their various constituents in order to compound them, in the same way that aviation fuels now are being "built" to meet exacting requirements. The work previously initiated to give the industry fundamental data on thermodynamics of hydrocarbons progressed satisfactorily, and the heats of combustion of 10 hydrocarbons in the lubricating oil -range of petroleum were determined. Thermodynamic data requiring highly specialized techniques are so broad in application that their commercial usefulness is not yet fully appreciated.

Jan 1, 1946

By James Spiers

This paper describing the mining practice at the Central-Eureka mine is one of a series of similar papers being prepared by the United Staten Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The mining practices described in this paper are illustrative of the methods employed in the exploitation of comparatively low-grade gold ores under the extremely heavy and swelling ground conditions which occur in the Mother Lode belt of California. The Central-Eureka Mining Co. comprises a group of adjoining mines in Amador County near Sutter Creek. The principal mines of the consolidated group are the Central-Eureka, formerly known as the Summit mine, and the Old Eureka mine, which is also known as the Hayward Quartz mine. The group is situated in the most productive part of tae main Mother Lode belt, the 10-mile portion which lies between the towns of Plymouth and Jackson. The three largest producing mines of the entire belt at the present time are the Argonaut, Kennedy, and the Central-Eureka; these lie within a radius of less than 1-1/2 miles.

Jan 1, 1931

By James J. Jessop, Richard E. Thill, Michael J. Friedel

As part of an investigation aimed at improving the health and safety and competitiveness of the mining industry, the U.S. Bureau of Mines evaluated the application of common offset radar profiling, using a 250-MHz ground-penetrating radar (GPR) system, for the detection of fractures in igneous rock. A series of radar reflection surveys were conducted to detect and delineate the extent of fracturing at various granodiorite and gabbro quarries and outcrops located in Minnesota. The application of radar profiling for detecting joints, sheeting fractures, shear zones, and depth to water table was demonstrated to be feasible with minimal processing. Radar reflection interpretations were verified by visual inspection of the rock mass and field mapping of local structure. The radar reflection section provides a simple, rapid, and cost-effective means for mapping of shallow (less than 10 m) small-scale fractures (greater than 0.25 cm) in igneous rock masses (characteristic of velocities between 0.061 m/ns for gabbro and 0.125 m/ns for granodiorite). Depth or distance estimates to fractures are within 10 pct of the actual, and time-shift compensation is necessary only when topographic irregularities exceed 30 cm.

Jan 1, 1992

By W. O. Vanderburg

The leasing or tribute system has been an important factor in the development of our metal-mining industry, particularly in the gold and silver mines of the Western States. It has received its widest application in. the early history of many camps and in the last stages of many mines. The system is especially adapted to mining where the ore&apos;s occur in narrow veins or are erratically distributed in small bunches or pockets so that selective mining, hand sorting, screening, or hand cobbing is required to produce shipping or milling-grade ore. The leasing system is also applicable to the development of prospects where the owners are unable or unwilling to assume the risks of searching for ore. The virtue of the system lies in the opportunity it affords miners with little capital to get started; at the same time, it rives owners an opportunity to have their property developed at small cost.

Jan 1, 1934

By Gary R. Gavan

This report presents the documentation and User&apos;s Manual for a data retrieval and report generation computer program. The program operates on a data base containing over 19,000 pieces of coal mine equipment in use in 1976.

Jan 1, 1979

A revolutionary development in blasting materials has occurred in recent years. Ammonium nitrate, sensitized by the addition of a small percentage of No. (class) 2 diesel fuel or other suitable petroleum product, has been adopted as a low-cost, efficient blasting agent2 in a wide variety of mining, quarrying, and heavy construction operations. Moreover, the ready availability of the component supplies throughout the Nation, together with the ease of formulating them into effective blasting agents, has made it possible for the blaster himself to prepare the mixes at the site of use. Recently, most established explosives manufacturers have begun supplying premixed AN-FO (ammonium nitrate-fuel oil) or a comparable product to various mining operations. However, many individuals and small business establishments are marketing premixed products prepared in facilities that are often poorly constructed and poorly located. Although these blasting agents have partly or wholly displaced explosives such as dynamites in many applications, there are some blasting operations in which the fuel-sensitized ammonium nitrate agents do not appear to be well adapted. As long as the hazards they present are clearly understood and respected, ammonium nitrate-based blasting agents have important safety characteristics when prepared under competent factory control or field-mixed under equivalent close control. This publication attempts to summarize the knowledge of those hazards and to incorporate practical ways to cope with them.

Jan 1, 1963

By Leonard Obert

The investigation reported herein is concerned with the generation and propagation of the strain wave produced in rock by the detonation of a high-velocity explosive. This report is the second of a series that will deal with this and related problems. The rock type in which these experiments were carried out was greenstone. Subsequent reports will discuss similar investigations in other rock types. Specifically, the problem under study is concerned with how certain characteristics of the strain wave, such as the maximum compressive and tensile strain, the maximum time rate of change of strain, the frequency components present in the pulse, the duration of the pulse, and other measurable characteristics, vary with the size of the charge and the distance from the detonation point to the point of measurement. . Other investigators have studied certain aspects of the generation and propagation problem in rock. However, in these studies the travel distances from the detonation to measurement point were comparatively long and the frequency components in the explosive wave were usually under 100 c.p.s. In this study the detonation to measurement distance covered. the range from 2 to 54 feet, and the strain gages and recording equipment employed in the instrumentation of the problem had a frequency response range from 200 to 10,000 c.p.s.

Jan 1, 1950

By A. J. Kraemer

This paper is the third and concluding report of the results of the United States Bureau of Mines twenty-third semiannual survey of motor fuel marketed in the United States. The first paper, reporting data relative to gravity, vapor pressure, and distillation range of the samples, was published as Report of Investigations 3129. The second report dealt with the data of the twenty-third survey in accordance with the revised specifications for United States Government Motor Gasoline. These data were published as Report of Investigations 3142.

Jan 1, 1931

By A. J. Kraemer

This paper is the third and concluding report of the results of the United States Bureau of Mines twenty-third semiannual survey of motor fuel marketed in the United States. The first paper, reporting data relative to gravity, vapor pressure, and distillation range of the samples, was published as Report of Investigations 3129.7 The second report dealt with the data of the twenty-third survey in accordance with the revised specifications for United States Government Motor Gasoline. These data were published as Report of Investigations 3142.8

Jan 1, 1931

By H. E. Powell

The magnetic susceptibilities of 34 manganese-bearing minerals were determined. The source of each sample and petrographic, spectrographic, and chemical analyses are given. Included are values for ismorphous series showing wide ranges of composition and for a few high-purity synthetic minerals.

Jan 1, 1968

By Everett P. Partridge, J. E. Conley

Available statistics show that the demands of the American chemical industry for sodium sulphate have been increasing slightly in recent years. The supply from domestic sources, particularly in the form of byproduct salt cake from the acid manufacturers, has been tending to decrease this to the growing manufacture of synthetic acid. Both hydrochloric and nitric acids are being synthesized from their elements. The natural result has been that a smaller amount of salt cake is available. Simultaneously, the expansion of the kraft-paper industry, especially in the South, has brought about greater demand for sodium sulphate in that section. This demand is being met by domestic byproduct salt cake, by imported German sodium sulphate made from potash waste liquors, and by favorably situated domestic deposits of Glauber salts and the anhydrous salt, thenardite. No shortage of natural sodium sulphate exists in the United States, but usually such deposits occur in semiarid regions far removed from transportation facilities and from markets. Moreover, the major portion of the natural deposits is Glauber salt or mirabilite (Na2 504 • 10H20), which must be dried or dehydrated in order to meet consumer requirements. The water of hydration represents, roughly, 55 percent of the total weight of the crude salts and therefore has a very important influence on transportation costs, in many instances the cost of getting even the dehydrated product to market is the deciding economic factor. Therefore, the recovery of production of anhydrous sodium sulphate from plant-waste liquors or from natural brines of suitable composition might be economically feasible.

Mar 1, 1936

By Jack L. Henry

The monocarbide region of the ternary system U-C-O has been investigated at 1,700° C as the first phase of a more extensive study of a portion of the four-component system U-C-O-N. An area bounded by the following compositional limits in atomic percent was studied: U, 44 to 55; C, 30 to 60; 0, 0.2 to 20. Compacts composed of mixtures of uranium, graphite, and uranium dioxide powders were sintered at 1,700° C under an equilibrium pressure of carbon monoxide to produce uranium oxycarbide specimens having a variety of compositions. Sintered specimens were evaluated by X-ray, chemical analysis, and ceramographic techniques. Solid-solution boundaries and phase relations have been established, and the effects of composition on the lattice parameter as well as the decomposition pressure have been investigated. Oxygen can be substituted for carbon in stoichiometric uranium monocarbide to the extent of about 17 atomic percent at 1,700° C. The composition range of the oxycarbide solid solution extends from about 48 to 51 atomic percent uranium in the low oxygen region. Above 10 atomic percent oxygen the composition range narrows to less than 1 atomic percent uranium. Carbon monoxide exists as a gaseous phase in equilibrium with all compositions which contain oxygen. Five separate phase fields were found bounding the solid-solution area. Other phases within this portion of the system include uranium, uranium dioxide, uranium dicarbide, and uranium sesquicarbide. Decomposition pressures of oxycarbide compositions at 1,700° C have been found to vary from a few microns for stoichiometric and uranium-rich compositions to 35 torr for carbon-oxygen-rich specimens. Lattice parameters were found to depend upon the U to C + 0 ratio as well upon the extent of substitution of oxygen into the stoichiometric monocarbide lattice.

Jan 1, 1967