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By H. Winkelmann

The author, who himself has worked inn the field with various types of torsion balances, expresses in the article his experience with the recently marketed Haff-Torsion-Balance. The advantages of practical work with Haff?s s torsion balance as compared with other types are mentioned. In spite of low weight and corresponding small dimensions (Model M = 23.5 kg., Model Al = 11.5 kg.) the sensitiveness is not less than that in the largest instruments. It is at 1.10-9, which is proved by calculations. A comparison with the corresponding values of other types of torsion balances (Eötvös, Askania, Gepege) is given. The mechanical features of the instrument are briefly described, and the balance is illustrated by a, cross section of it. -- W. Ayvazoglou. DETERMINATION OF THE ELEMENTS OF THE MAGNETIC AND GRAVITATIONAL FIELDS INDUCED BY AN INFINITELY LONG HOMOGENEOUS CYLINDER By G. A. Gamburzeff Gerlands Beiträge zur Geophysik, Band 19, Heft 2/3 Leipzig, 1928, pp. 210-230. The present work is a. contribution to the quastion of the reason for the magnetic and gravitational anomalies in the government of Kursk (Russia).

Jan 1, 1929

By Anthony W. Sparks

The Bureau of Mines conducted tests designed to compare its breathing metabolic simulator (BMS) with other methods that are currently used to evaluate the performance of respiratory protective equipment. The BMS is a commercially developed device that uses a piston cylinder to simulate breath movement. Using a propane furnace that consumes oxygen and forms CO2, the BMS also simulates the respiratory metabolism of humans. The breathing and metabolic subsystems of the BMS are described in detail in this report. Results are compared from tests that used the BMS to evaluate respiratory equipment and from tests that used human subjects for the same purpose. The BMS was also tested against a pulsatile breathing machine (PBM) previously designed by the Bureau. Both machines were used to test respiratory equipment, and the test results are compared in this report. To illustrate typical applications of the BMS, the report briefly describes how the BMS was used to test two different types of closed-circuit respiratory apparatus, and the test results are presented. This research showed that BMS test results compared more closely to the results of tests that used human subjects than did results obtained using the PBM.

Jan 1, 1980

By R. F. Zaffarano

Reservoir oil in the Greater Aneth area, Utah, part of the Paradox basin, was studied to detect variation in oil characteristics within the reservoir and to determine its relation to age of accumulation and fluid equilibrium. At least three subsurface oil samples were obtained from each of the four largest of five field divisions comprising a producing area of 45,000 acres. Height of the oil column in the Pennsylvanian Desert Creek zone is about 230 ft. In general, the oil characteristics were found to be uniform across the area, and averages were developed for use in engineering applications. Average saturation pressure was 1,780 psia; the oil was undersaturated at the initial reservoir pressure, 2,200 psia. Variation in saturation pressure shows a lack of complete fluid equilibrium and continuing diffusion of solution gas from the main body of the reservoir to two extensions linked by narrow arms. By assuming early accumulation, the time involved in this diffusion process was calculated to be about the same as the age of the reservoir formation. Cause of the concentration of gas in the main body is attributed to differential entrapment during accumulation of oil and gas from an exterior source.

Jan 1, 1963

By W. L. Heidenreich

This report describes the methods and results of field investigations conducted by the Bureau of Mines between December 1956 and December 1957 on seven deposits of nickel-cobalt-iron-bearing laterite and weathered serpentine near the west coast of Puerto Rico east and south of Mayaguez. These deposits were named, for purposes of identification, Guanajibo, Punta Guanajibo, Las Mesas, north and south deposits of the Rosario Southeast group, and the west and east deposits of the Maricao Southwest group. In addition, the lower 17 miles of the Guanajibo River Valley was tested at widely spaced intervals for possible concentrations of magnetite and chromite in the alluvial sands. The objective of the investigations was to appraise, by drilling and sampling, the two largest deposits--the Guanajibo and Las Mesas. Testing of the smaller deposits was much more restricted. Field investigations consisted of mapping, drilling with power auger, sampling drill-hole sections, and pre-paring samples for chemical analyses, mineralogical studies, and metallurgical tests. The work was financed jointly under a cooperative agreement by the Bureau of Mines and the Economic Development Administration, an agency of the Puerto Rican Commonwealth.

Jan 1, 1959

By H. S. Caldwell

This report describes work by the Bureau of Mines on the vacuum distilla¬tion of some of the more volatile metals such as cadmium, zinc, and magnesium from lead and tin. Evacuation within a distillation apparatus allows rapid diffusion of vapor away from the evaporation surface and prevents reaction of the vapor with residual gases. A reduction of pressure to several tenths of a millimeter makes possible practicable distillation rates, at temperatures for which the partial pressure of the metal vapor exceeds 10-3 atmosphere. The rate and selectivity of distillation depend primarily on the volatility and molal ratios of the alloy metals, and their chemical activity to each other. For very rapid evaporation or low concentration of the more volatile constituent, the rate is determined by the rate of diffusion of the evaporating metal, to the surface of the melt. Cadmium, zinc, magnesium, and tellurium were found to volatilize readily from both lead and tin. Tellurium appears to volatilize as an intermetallic compound rather than the pure metal. Antimony could not be removed from lead at 1,000° C.; the condensate was nearly all lead. Antimony, bismuth, and lead were removed from tin.

Jan 1, 1960

By George H. Schnakenberg

This Bureau of Mines publication describes a passive personal sampling device for N02 in air, developed by the New York University Medical Center under Bureau Grant G0133066. The sampler has been successfully demonstrated in the field and in the laboratory. In corroborative laboratory trials the agreement with reference method is excellent. The overall accuracy is approximately ±5 pct of reading to a precision of about ±l pct. All evidence indicates that these samplers should indicate the time-weighted-average N02 concentration to the above accuracy and precision equally well in the field since effects of wind velocity and relative humidity are negligible and the effects of temperature are about 0.1 pct per °F. The duration of exposure and the approximate temperature are the only data that need to be collected in the field. A two-step analysis procedure in field or service laboratory is then used to obtain the total cumulated exposure to N02 in parts per million-hours (ppm times hours), which can be converted to the time-weighted-average concentration of N02 in ppm by dividing cumulated exposure by the duration of the exposure.

Jan 1, 1976

By Jerome J. Hoeppner, Walter W. Fowkes

The Federal Bureau of Mines has determined the distribution of forms of sulfur for several lignites and gasification chars and noted the changes induced by the gasification process . A method was adopted for quantitatively determining sulfide sulfur that was found to be present in the chars , although absent in the lignites . Changes in the behavior and distribution of sulfur forms were further investigated concerning the ashing of lignites and chars under standard conditions , as well as at various temperatures , and the determination of volatile matter applied to both chars and lignites . The authors concluded that the first and greatest change in the form of sulfur present in natural lignite , upon heat treatment , resulted from the reduction of pyritic and sulfate sulfur to sulfide . Organically - bound sulfur originally present is less reactive , but largely disappears on strong ignition . An appreciable part of the sulfur content of natural lignite is fixed in the char as sulfide and in the ash as water - soluble sulfate and will affect the summation of constituents , to a greater or lesser degree , in reporting the ultimate analysis of a lignite or char .

Jul 1, 1960

By D. H. Baker

THIS REPORT presents the technique and equipment used in determining the hardness of titanium sponge. Detailed descriptions are given of the methods used in preparing test samples for chemical analysis and hardness testing, the method of melting and surfacing test ingots, and the technique of reading Brinell-hardness impressions. The arc-melting furnace described, for which engineering drawings are included, will produce from 70 to 90 double-melted buttons each 8 hours of operation. Experimental data are also presented depicting the effect on hardness of the methods of surfacing specimens, temperature of test specimens, and the effect of time at test load. These data show that surfacing of the specimen involves no critical machining operations but that the test surface must be paralleled by a relatively flat surface for contact with the anvil of the Brinell tester. The heating of a specimen to 150° C. during surfacing does not materially affect the results if the ingot is cooled to room temperature before the hardness impressions are made. The optimum time at load appears to be approximately 30 seconds, but load times of as much as 1/ ½ minutes will not cause major errors.

Jan 1, 1959

By C. H. Herty, J. K. Gaines

"Nearly every piece of electrical equipment used in mines ""breathes."" In other words, motors, controllers, rheostats, switches, and other similar equipment, even though encased in seemingly tight compartments, breathe in the atmosphere that surrounds them.As the apparatus is used, the temperature of metallic parts is changed generally in positive direction through the heat by friction and the heat due to the electric current. When the apparatus is idle it gradually cools down to the temperature of the surrounding atmosphere.This increase of temperature during operation and return to normal temperature when operation stops alternately raises and lowers the temperature of the atmosphere within the compartments which, in strict accordance with Charles' law -T = VT1 V'will expand or contract in proportion to any given temperature change.As compartments are not gas-tight, such expansion and contraction will force the atmosphere out of the compartment =on expansion and suck the surround¬ing atmosphere into the compartment during contraction, hence the term ""breathing.""Investigators of explosion-proof equipment have recognized that such an interchange would take place and have designed their equipment to safeguard possible explosions within the compartments."

Jul 1, 1927

As part of remote sensing research on an abandoned mine lands (AML) site in the Colorado Springs, Colorado area, a geographic information system (GIS) database was generated. This GIS database contains information on the locations and extents of abandoned underground coal mines, the geology of the area, subsidence features and degrees of subsidence risk, topography, drill hole locations, and lineaments (linear features) related to subsurface geologic structures. A GIS database allows the reproducible and accurate comparison and analysis of any data sets which geographically overlap and are within the same coordinate system. The database has been released to the public domain so that government agencies, researchers, educators, and the general public can access this coherent database for the purposes of better understanding the study area and GIS technology. Data files and maps are available in formats that are compatible with the GIS software used in the research project and with most CAD systems so that as many people as possible can make use of the majority of the database. This document serves as the data dictionary for the database by providing descriptions and origins of the data files.

Jan 1, 1992

By A. L. Engel

The sample of ore on which the work described in this paper was done came from Mina Oriente, Carrizal Bajo, Provincia de Atacama, Chile, South America, and was sent at the request of the Chil.ean Government through the Foreign Minerals Division of the Bureau of Mines. This ore had been tested locally for treatment by flotation and cyanidation without satisfactory results. An additional difficulty was the absence of water near the ore deposits, so that in any treatment method considered the water requirements would have to be very low. It was desired to develop a practical method of recovering the gold and, if possible, the copper in the area. No data of previous investigations were made available. The sample received was mostly quartz, highly brecciated, with limonite and hematite in the fractures. Copper occurred as malachite and azurite, also in the fracture s and to a slight extent as a stain in the quartz. Some fine-grained pyrite with a little arsenopyrite occurred within the quartz. An occasional grain of chalcopyrite was observed. No free gold was seen during examinations of the ore, but amalgamation indicated that some was present.

Jan 1, 1949

By Robert B. Fisher

[The purpose of this paper is to acquaint manufacturers of various types of asbestos product's, particularly those that specialize in materials used for sound deadening, vibration damping, and filtration, with a recently invested depth deposit of paligorskite, a type of asbestos usually called mountain leather. In the past this mineral has been only a museum curiosity but it possesses characteristics that may adapt it to industrial uses. The deposit is on Lemesurier Island, near this entrance to Glacier Bay, in the northern portion of southeastern Alaska, at approximately latitude 58° 17? N., longitude 1360 05' W. The island is about 4 ½ miles in east- west length and miles in width. The property on which the deposit occurs is owned by the locator Joe Ibach, end it was brought; to the attention of the Bureau of Mines by Col. George B. Norris. A Bureau of Mines engineer, accompanied by the owner and Chris Ellingen, visited the property sand examined the open-cuts from May 7 to 10 in 1944. The purpose of the examination was to determine the approximate extent of the occurrence and to obtain samples of the material for identification end study of its utilization.]

Jan 1, 1945

By J. P. Barkley

"The accompanying tabulation gives the results of a series of operating tests on two types of small stokers. One was an inclined, natural-draft, moving-grate, overfeed ""hand-stoker"" fired and manipulated by hand; the other was. a horizontal, forced-draft, stationary-grate, underfeed, mechanical unit-stoker operated by an electric motor. These were installed as shown by the accompanying sketches (figs. 1 and 2) under horizontal return tubular boilers of a nominal rating of 150 bl.h.p. each.The steam load carried by these boilers was a rather typical heating load. It was fairly constant and of about 30 bl.h.p. throughout the summer months, with small variation between day and night. During the winter months the daily variations were dependent upon the outside temperature. The boilers were banked a considerable part of the night.As noted in the table, two kinds of coal were used. The size of one kind was run-of-mine and the other 11/4 inch nut and clack. These coals from two different mines of the New River district both caked considerably during burning, the nut and slack more than the other. Analyses of the coal were as follows:"

Jun 1, 1929

By S. H. Ash

California leads the Nation in the number of operating metal mines and the small number of persons employed at individual mines, which reached a minimum irk 1932 with an average of seven men. The mines are scattered over the entire State, which is the second largest in area (155,562 square miles) in the United States. The mines are situated at various altitudes, with portals ranging from approximately 300 feet below sea level to almost 12,000 feet above. Many of the mines can be reached only during the summer, while at others the heat of the regions adds so the difficulties during the summer months Supplied of explosives the use (or, probably more correctly, the misuse) of which constitutes one of California's gravest mining problems; are handled and stored under condition that contribute many hazards. The problem of providing medical care is serious and complicated, especially at small mines and more particularly in the almost inaccessible mountainous regions; instances in which a knowledge of first aid would have been beneficial but was lacking, or when first aid was instrumental in saving life or limb because it was available are too numerous to be mentioned.

Jan 1, 1936

By P. A. Rey

Water recycle is an important part of the coal preparation process. This study was directed toward: (1) a survey of current practice and an evaluation of both the solid and liquid components of blackwater, (2) an experimental study of blackwater flocculation, and (3) a fundamental analysis of the flocculation process. The solids contained in the blackwater discharge to the fine refuse thickener of a coal preparation plant were found to contain, on average, 56% coal and 44% mineral matter. The mineral matter was largely illitic clay, while the water phase contained relatively large amounts of S04 and Ca++. Detailed studies were made of both natural and synthetic flocculants and the influence of polymer type and pH on the settling rate, turbidity of the supernatent liquid and sludge volume of the settled solids. More tundamental studies were made that clearly indicate the need for controlled mixing of polymer into the suspension to be flocculated, and the need to evaluate, more closely, the structure of the flocs formed during the process. Research recommendations are given.

Jan 1, 1983

By Victor E. Kral

"INTRODUCTION The Segerstorm-Heizer property was examined by engineers 3/ of the Bureau of Mines in May and June 1942 and Mach 1943. As a result of these examination, the Nevada State Department of Highways,constructed 9.3 miles of graveled road under the mine access-road program. A magnetometer survey was made by the Geophysical Division 4/ in October 1943, and as a result the Mining Branch set up and conducted a core-drilling,project. Work on the deposit started May 24, 1944, and was suspended on July 31, 1944, but was resumed on December 4, 1944 and continued until completion on March 27, 1945.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as it, primary objective the more effective resource to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploration work, and prepares the final report. The Metallurgical Branch, R. G. Kinickerbocker, chief analyses samples and performs beneficiation tests."

Mar 1, 1947

By Winton J. Gale

Coal pillar design has been based on generalized formulas of the strength of the coal in a pillar and experience in localized situations. Stress measurements above and in coal pillars indicate that the actual strength and deformation of pillars vary much more than predicted by formulas. This variation is due to failure of strata surrounding coal. The pillar strength and deformation of the adjacent roadways is a function of failure in the coal and the strata about the coal. When the pillar is viewed as a system in which failure also occurs inthe strata rather than the coal only, the wide range of pillar strength characteristics found in the United Kingdom, United States, Republic of South Africa, Australia, People's Republic of China, Japan, and other countries are simply variations due to different strata-coal combinations, not different coal strengths. This paper presents the measured range of pillar strength characteristics and explains the reasons. Methods to design pillar layouts with regard to the potential strength variations due to the strata strength characteristics surrounding the seam are also presented.

Jan 5, 1999

Provide long-term measurement of mine sidewall closure in backfilled stapes subject to flooding. Approach A water resistant extensometer is made by enclosing a rod-actuated transducer in a telescoping tube which is enclosed within an oil-filled outer housing. How It Works To assemble a water resistant extensometer, a cylinder -shaped transducer and two support rings are pushed into the small-diameter section of the telescoping tube where the transducer is held in place by friction. The outside of the small-diameter section of the telescoping tube is then greased and slid into the slightly larger-diameter section. See drawing. The cylinder-shaped transducer contains a potentiometer whose actuating arm is attached to a stainless steel extension rod that passes through one end of the telescoping tube. A similar rod is attached to the opposite end of the transducer body, and extends through the other end of the telescoping tube. A coil spring inside the large diameter end of the telescoping tube extends the tube

Jan 1, 1978

By D. S. Colby

Statistics on the volume of natural gas produced in the United States were first collected for 1906. A summary of those statistics covering 1906-35 was incorporated in the 1937 Minerals Yearbook. This summary, covering 1936-50 presents, by States, a number of the more important statistics that have appeared in the natural-gas chapter of the Minerals Yearbooks. The period covered has been one of rapid expansion, especially of long-distance transmission lines. Natural gas was made available to some States for the first time; in other States the degree of dependence upon supplies transported from outside their boundaries changed rapidly. Thus, an isolated series of statistics cannot be studied without considering other regional influences that reflect in the overall operations of the industry. These tables accordingly have been designed to show for each State the simultaneous changes taking place in the various sectors surveyed. The tables show production data in the upper portion and consumption data in the lower portion. They are arranged alphabetically, by States. A copy of the 1906-35 production summary from the 1937 Minerals Yearbook has been included.

Jan 1, 1952

Assure fail-safe stopping of a mining vehicle immediately following a loss of electric power. Approach A separate emergency brake system which actuates when electrical power is interrupted, was installed on several mining vehicles and tested in a long-term underground mining demonstration. How It Works Separate, spring-actuated brakes, which press against brake discs, are used to stop the vehicle following power failure. To allow norm al movement of the vehicle, hydraulic oil under pres? sure from the vehicle's hydraulic system is directed to a spring? loaded piston in each emergency brake housing. That pressure causes the piston to compress the spring and relieves the spring pressure against the puck, thereby allowing the brake disc to turn freely. See Figure 1 A. If the electrical power fails or if the machine is turned off, a valve in the hydraulic line to the emergency brakes opens. That valve, shown as ?Solenoid Valve (automatic)" in Figure 1, which is normally held closed by its electrical solenoid while the vehicle is electrically powered, is opened by the spring in the valve assembly. The pressure in the hydraulic line which is connected to the emergency brakes then drops to

Jan 1, 1978