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By Oliver Bowles

The wire saw, introduced by the Bureau of Mines about two years ago, has revolutionized slate quarrying in Pennsylvania. The success of the saw since its early accomplishments has become greater and greater as the equipment has been perfected and skill acquired .in its use. In the first test made, a cutting rate of 9.7 square feet per hour was attained; in the next four cuts, made early in 1927, the average rate of cutting was increased to 12.8 square feet per hour; in 1928 a maximum of 34 square feet per hour had been attained, with a general average of about 20 to 25 square feet, The wire saw is now regarded as essential equipment in practically all of the quarries in the Bangor, Pen Argyl, and Windgap districts. The wire saw consists of a three-strand steel cable of 3/16 or 1/4 inch diameter running as an endless belt. The driving pulley is a 40-inch double-groove cast-iron sheave. A tension pulley supported by a frame mounted on wheels may travel back and forth on a short track. A weight of 800 to 2,000 pounds gives the desired tension on the wire. The driving units consist of electric motors with direct-drive compactly enclosed gear reduction, or double-belt speed-reduction units; the former is preferred. Silent chain and. pinion gear reductions are used to a limited extent. The travelling speed of the wire is about 15 feet per second. The driving and tension equipment are shown in Figure 1, A.

Jan 1, 1929

By L. B. Pankratz

The heat contents of the sesquioxides of erbium, holmium, thulium, and ytterbium (Er203, Ho203, Tm203, and Yb203) in the cubic crystalline form were measured over the temperature range from 298° to 1,800° K. The erbium and holmium sesquioxides gave regular heat content-temperature curves. Thulium sesquioxide had a minor thermal anomaly near 1,680° K, with a heat absorption of 310 cal/mole; similarly, ytterbium sesquioxide had a minor anomaly near 1,365° K, with a heat absorption of 150 cal/mole. The heat content results are presented in both tabular form (at 100° intervals) and in algebraic form. Entropy increments, corresponding to the tabulated heat content results, also are listed.

Jan 1, 1963

By James P. Bennett

In this Bureau of Mines study, portions of four acidproof bricks (two red shale and two fireclay) were exposed to 20 wt pct RCI at 900 C for periods of 30 days. Three different techniques were selected to deter-mine volume expansion of these materials after exposure. Linear expansions ranging from about 0.02 to 0.12 pct were noted from Ta pin and dilatometer measurements. The use of strain gages to measure expansions was not successful. The red shale and fireclay brick with the lowest apparent porosities had the lowest expansions. Expansion data obtained by direct measurement of samples exposed for 30-day periods or by dilatometric measurement of autoclaved samples ex-posed for 2 h were comparable. This suggests the use of an accelerated autoclave exposure procedure for determining volume expansion effects of ceramic materials in acid environments.

Jan 1, 1985

By John W. Buch

Upon review of German World War II mining practices and equipment for planning coal, the Federal Bureau of Mines initiated research leading to the development of a pneumatic planer for anthracite. The results of tests are reported in this manuscript. It was demonstrated (1) that hard anthracite can be planed and (2) that the design and operating requirements are within the limits of present-day engineering and technology. For hard anthracite, the depth of cut indicated is 4 to 6 inches; with a chain pull of 20 to 40 tons and the speed of planer travel of 18 to 20 feet per minute, a 40-hp. motor will be required for the planer hoist. Compressed-air requirements for the planer will be 250 to 300 c, f, m, at 60 to 70 p. s, i. It was learned that the length of the 4 individual sections of the planer should not exceed that of the individual troughs of the armored chain conveyor (5 feet in this instance); otherwise, bottom coal will be left in synclines, and the planer will override the conveyor at anticlines. Pneumatic pushers should be operated from a separate compressed-air line fitted with a pressure regulator. Results indicate that additional development work is warranted.

Jan 1, 1957

By Natalie A. Sapola, Knox Van Dyke, Jean Rabovsky, Vincent Castranova, William H. Pailes, Melanie McPeek, Deloris J. Judy

"INTRODCJCTJONPlatelet activating factor (PAF) is a glycerophospholipid (1-0-alkyl-2-acctyl-sn-glycerol-3-phosphoryl choline) which has been shown to mediate a broad range of biological activities. 1·3 Its pulmonary actions include contraction of pulmonary tissue,4 secretion of leukotrienes from leukocytcs,5 airway constriction,6 pulmonary edema,7 and enhanced migration of neutrophils into the airspaces of thelungs.8-9PAF can be released from several different cell types, such as, basophils, neutrophils and alveolar macrophages, in response to a variety of particulates or membrane stimulants which include zymosan, calcium ionophore, phorbol esters, chemotactic agents, and endotoxin. 1~1 3 Therefore, PAF may play an important role in the development of pneumoconioses by mediating pulmonary responses of lung cells to a variety of occupational dusts. To investigate this possibility, we determined the effects of P AF on several physiological parameters of neutrophils, alveolar macrophages, and alveolar type Il epithelial cells.METHODSIsolation of CellsNeutrophils were isolated from human blood by dextran settling and centrifugal elutriation.14 Isolated neutrophils (93% pure) were resuspended in HEPES-buffered medium (145 mM NaCl, 5 mM KCI, 10 mM HEPES, 5 mM glucose, and 1 mM CaC12; pH = 7.4). Cell number and volume were determined with an electronic cell counter equipped with a sizing attachment.Rat alveolar macrophages were obtained by pulmonary lavage with ea2+, Mg2+-free Hanks balanced salts solution. 15 Alveolar macrophages (94% pure) were resuspended in HEPES-buffered medium, counted, and sized electronically.Rat alveolar type Il cells were isolated by enzymatic digestion for 35 minutes at 37°C with 40 µ/ml type I elastasc and 0.1 % collagenase and purified by centrifugal elutriation. 16.17 Type Il cells (92 % pure) were resuspended in HEPES-buffered medium for measurement of membrane potential, oxygen consumption, and trypan blue exclusion. Type Il pneumocytcs were resuspended in 0.1 M NaCl plus 0.05 M HEPES (pH = 7.8) to measure cytochrome P450-dependent activities and aggregation. Cell size and number were determined electronically."

Jan 1, 1990

By E. C. Lane

Although motor gasoline marketed in the United States in January of this year was, on the average, slightly more volatile than that sold in January 1925, the improvement in quality is too small to be of importance. In other words, there is no evidence that any radical change in the quality of gasoline is being made at the present time. During the past six years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States, the survey just completed being the thirteenth in the series. The cities in which samples have been collected have been chosen as representative of the more important marketing territories as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country.

Jan 1, 1926

By Margaret R. Egan

A study of the combustion emission products of rigid ventilation ducting was completed by the U.S. Bureau of Mines. The ducting was composed of fiberglass-reinforced polyester resin. Four properties of the ducting were evaluated: (1) propensity to ignite, (2) smoke characteristics, (3) gas emissions, and (4) heat release. Particle sizes, obscuration, optical densities, and production constants for gas and smoke were also calculated. These results provide comprehensive data about the emission products, detectability, and relative hazards of fiberglass-reinforced plastic ducting and other mine combustibles under realistic fire conditions.

Jan 1, 1990

By Alfred L. Ransome

The plan to develop a standard system of names and definitions of regions and districts in Alaska was borne of the need for a tool to use in statistical and economic studies of the mineral industry of the Territory. The purpose of this report is to present to the mineral industry, and to those individuals interested in the mineral or allied industries in Alaska, the system used by the Bureau of Mines in connection with its legal function of collecting and disseminating mineral statistics. It is hoped that the specific descriptions given will result in a more complete understanding of what is meant by the regional and district names that appear in publications of the Bureau of Mines relative to the mineral industry of the Territory. Problem of Standardization of Names and Definitions The question might be asked, does the naming and defining of regions and districts in Alaska present a problem relative to the establishment of a standard? Is it necessary to establish a standard?

Jan 1, 1954

By W. H. Coghill, B. W. Gandrud, F. D. DeVaney

"The self-fluxing iron ores of Alabama are the foundation of the thriving iron and steel industry of that State. In addition to these deposits of self fluxing ores there are seams containing practically the same percentages of iron but too much silica. These ores at present are valueless, but if they could be concentrated by reducing the silica content, the ore reserves of the Birmingham district would be greatly augmented. A detailed report on the iron-ore deposits of the district, describing the types of ore and their extent, has been published.In forwarding its mineral conservation policies the United States Bureau of Mines has given some attention to the siliceous ores of this district.The low cost of gravity concentration gives this process first rank in the beneficiation of iron ores. For this reason many experimenters have tried to concentrate the Alabama iron ores on tables. In the face of the early failures a new trial has been made and the results have justified the effort.In this work more attention than formerly has been given to the physical, properties of the ores. The removable siliceous gangue is in the form of oolitic grains which ""shell"" out like corn, leaving the hematite as rich high-grade ""slime"" and as clean granular grains. The ""slime concentrate"" may be recovered by well known desliming processes. The oolitic grains and granular hematite are separated on tables."

May 1, 1929

The Bureau of Mines analyzed the cycle of secondary gold to determine the quantity of gold not being recovered from scrap, and to identify areas for research to increase the supply of gold from scrap. Secondary gold in 1967 was estimated to be 2.4 million troy ounces; this excludes secondary gold which is recycled within consuming plants. Firms contacted included consumers using about 41 percent of the gold in 1967, And refiners that recovered about 90 percent of the secondary gold. Results of the study indicate that loss of gold is small, and refiners and consumers are accelerating programs designed to reduce recovery costs. With the increasing generation of low-grade industrial scrap, research is needed to improve present recovery techniques and to develop methods to accelerate the flow of secondary gold back to supply.

Jan 1, 1970

By F. B. Petermann

The Bureau of Mines conducted electric furnace smelting tests on sintered flotation concentrate and siliceous log-washed are. The flotation concentrate was derived from the Maggie Canyon deposit of the Artillery Mountains area, Mohave County, Ariz., and contained, before sintering, 35.6 percent Mil and 19.4 percent Si02 + A1203. The log-washed ore was from the McGregor deposit of the Artillery Mountains area, Mohave County, Ariz., and contained 31.2 to 33.6 percent Mil, 19.5 to 27.6 percent Si02 + A1203, and 2.5 percent Pb. This work was undertaken to determine the most effective smelting technique for producing standard products from such nonspecification ore and concentrates. The objective was to collect data, using a small furnace, which would be reasonably accurate and permit extrapolation to large-scale practice for comparing with results on specification-grade are.

Jan 1, 1962

By Henry C. Meeves

The Bureau of Mines investigated the silver production potential of the Leadville (California) mining district, Lake County, Colo., in 1966-67. The mining history of the district, the ground conditions encountered in mining, and the mine-support methods used are reviewed. The drainage problem is discussed in detail. An initial objective was to establish the existence of potential silver resources minable by low-cost open-pit methods, particularly in the silver-bearing manganese halos surrounding the major deposits. The report concludes that under present conditions, development of the deposits in the area is not economically feasible; however, a pioneer rotary noncore drilling program demonstrated that this type of exploration is technically feasible. Potential reserves of silver and associated metals are estimated. Possible mining methods for recovery of the reserves are discussed. Future production possibilities from the various subareas of the district are analysed, considering optimum operating size. Consolidation of small individual holdings for unit operation is recommended. Type of operation, amount of rehabilitation, size and type of concentrating plants required, drainage and other mining problems, and metal price trends are discussed as they bear on economic feasibility of development.

Jan 1, 1970

"The Generic Mineral Technology Center on Respirable Dust was established in August 1983, at the request of the Bureau of Mines, to conduct research that affords ""...each miner the opportunity to work underground during the period of (his/her) adult working life without incurring any disability from pneumoconiosis or any other occupational disease"". The Center consists of the Mining and Mineral Resources Research Institutes (MRI) of The Pennsylvania State University (PSU) and West Virginia University (WVU) in association with the MRIs of the Massachusetts Institute of Technology (MIT) and the University of Minnesota (UMN). (FIGURE 34) Michigan Technological University (MTU) is also affiliated with the Center in the area of diesel particulates.The Center brings together experts concerned with particles causing potentially disabling or fatal diseases including pneumoconiosis (""black-lung""), silicosis, and asbestosis. The latter is of deep concern not just to workers in the mineral sector of the economy but also to the general populace. The primary goal of the Center is to reduce the incidence and severity of respirable dust disease through advancing fundamental understanding of all aspects of respirable dust associated with mining and milling, and the interaction of dust and lungs. The research program of the Generic Mineral Technology Center explores these scientific, engineering or medical concerns with the objective of refining existing strategies and developing new respirable dust control techniquesand technology that are consistent with the fundamental dust-lung interaction processes that lead to mine worker disability. The work concentrates on five areas (FIGURE 35):"

Nov 1, 1988

By Max J. Spendlove

The secondary copper industry is comprised of numerous enterprises which collectively employ many of the recovery and refining processes now used in primary plants as well as many other processes that are unique to the industry. Effective methods are used for identifying and segregating all types of scrap according to widely accepted standard classifications. Segregated scrap and waste materials usually require some preliminary processing to remove both valuable and deleterious associated constituents. Smelting, melting, alloying, and pyrorefining are common methods used for producing secondary metal, but operating techniques usually differ from primary metal operations because of the difference in physical and chemical properties of the respective raw materials. Some copper scrap is converted to copper chemicals rather than to refined metals or alloys. Recovery efficiencies of all processes are reasonably high, and the quality of products meets rigid specifications.

Jan 1, 1961

By Charles D. Litton

This U.S. Bureau of Mines report details the results of a series of large-scale experiments where small coal fires were used to ignite the conveyor belt at air velocities ranging from 0.76 to 6.1 m/s. In the tests, electrical strip heaters imbedded within a pile of coal were used to heat the coal to a point of flaming ignition. The flaming coal subsequently ignited the conveyor belt located approximately 5 to 10 cm above the coal pile. During the tests, temperature, CO, and smoke levels were continuously measured in order to determine both alarm time and level as the fire intensity progressed through the stages of smoldering coal, flaming coal, and flaming coal plus flaming belt. Analysis of the data leads to certain conditions of air velocity and sensor alarm levels that are required for early detection of conveyor belt entry fires. Two nomographs are presented, which define sensor alarm levels and sensor spacings as a function of belt entry cross-sectional area and belt entry air velocity.

Jan 1, 2010

By R. L. Brown, H. G. Berger, E. F. Pohlman

"The Bureau of Mines in cooperation with the American Gas Association investigating the relation of properties of gas oils to the gum-forming properties of carbureted water gas. The present report deals with the effects of operating practice on the composition of the light oils from carbureted water gas. A general outline of the gummy meter problem has been presented in a previous paper.*Carbureted water gas is a mixture roughly of 80 per cent water gas by volume and 20 per cent oil gas. The latter, though small in relative volume, supplies more than half of the heating value of the gas under the present-day standard. Therefore, it is logical that the oil used in the carbureting process and the operating practices involved should be subjected to scientific study. Many investigations***** bearing on the aspects considered in this paper have been carried out in the past."

Oct 1, 1923

Although alternating-current (a.-c.) power systems and equipment have been used in coal mining for many years, most mines in the United States are powered mainly by direct current (d.-c.). There are several logical reasons for this, but the use of d.-c, equipment is, in most instances, a direct outgrowth of the original practice of using such power for haulage systems. For traction equipment such as the electric trolley locomotive the d.-c. motor has ideal operating characteristics, and thus it has been widely used for haulage locomotive service. The first efforts at electrification of coal mines started with the haulage system and from there branched out to include the many types of electrically powered mining machinery used in the industry today.

Jan 1, 1960

By Richard W. Knostman

A study was made of the factors affecting lead and zinc production in the Pacific Northwest. Costs, ore reserves and potential resources, and domestic demand were analyzed. It was concluded that a projected 3.1-percent average annual increase in U.S. demand for zinc through 1975 and a corresponding 2.5-percent rise for lead will be supplied mainly from mines in the Eastern and Central States. Annual Pacific Northwest mine production of lead is estimated to fluctuate around 82,000 tons, while zinc output may average 135,000 tons through 1975. Measured, indicated, and inferred reserves in the Pacific Northwest, containing 1.56 million tons of lead and 2.59 million tons of zinc, are more than sufficient to maintain this level of production. Annual production from Pacific Northwest electrolytic zinc plants is expected to increase to over 300,000 tons of slab zinc by 1975. Lead smelters may experience difficulty in maintaining output at 1964 levels.

Jan 1, 1967

By Irving Hartmann

In recent years various modifications in the methods of blasting have been tried as a means of increasing the production of cod and of reducing mining costs. Following an investigation by the Bureau or Mines, authorization was granted to increase the charger limit for permissible explosives par shot hole from 1.5 to 3 pounds under contain conditions; this greatly facilitates the blasting of coal in some cool fields the practice has gradually evolved of simultaneously charging several shot holes in a face and then firing the charges singly without inspecting for gas after each blast. This practice is disapproved by the Bureau of Mines. In other coal mines the explosive chews in several adjacent shot holes are fired simultaneously. This form of shooting is claimed to increase the rate of production, generate smaller volumes of noxious gases, promote the health and safety of workers by eliminating the need of inspection of the face after each charge is fired, produce less float dust, and require less explosive than single shooting. However, simultaneous blasting may have a more harmful effect on the immediate roof strata; in some instances it leads to wedging of the broken coal, thereby making the coal more difficult to load out; it makes misfired shots more difficult to detect and possibly increases the chances of misfires. This lacy be duo to variations in the characteristics of detonators, because of more stringent requirements for adequate firing current, to the need for better electrical connections in the shot-firing circuit, and partly to the inadequacy of present permissible multiple blasting devices.

Jan 1, 1952

By Sathit Tandanand

This report presents a Bureau of Mines study on the time-dependent behavior of coal measure rocks for future implementation in stability analysis and safety evaluation of in-mine rock structures. This initial study focused on moisture adsorption rate and strength degradation of shales in Pennsylvanian coal-bearing strata in the Illinois Basin. A reaction of clay minerals in Illinois shales with atmospheric water vapor was hypothesized as the adsorption and strength degradation mechanism. Part of energy exchange between shales and the environment was attributed to a free energy controlled by pore pressure of the rock and partial pressure in the environment. The relationships between adsorption versus time and strength degradation versus moisture content were derived and correlated with the experimental data. Partial saturation at various levels of relative humidity occurs within approximately 2 weeks at room temperature. The strength of shales tested decreases linearly with increasing moisture content. When the moisture exceeds 7 pct of the dry weight, these Illinois shales become unstable. To this end, the moisture content is a good predictor of rock strength for shales.

Jan 1, 1987