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By Edmund S. Leaver

[In previous reports 5/ of ore-testing studies standard methods of conduction tests with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail.]

Jan 1, 1941

By Edmund S. Leaver

[In previous reports5/ of ore-testing studies standard methods of conducting; test with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail. In addition to standard tent procedures such as direct cyanidation, amalgamation, gravity concentration, and flotation, or a combination of these methods, it is sometimes necessary to apply other methods, such as preliminary roasting and washing of the calcine with plain or acidulated water before cyanidation. In all of this work standard tenting procedure has been supplements by he necessary assaying and analyses of original ore and test products.]

Jan 1, 1941

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations No. 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the sixth. The data are accompanied by maps showing the loca.ion of holes, drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test geophysical anomalies. The locations of those holes are shown on figure 13 in Volume I. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By C. W. Owings

The Bureau of Mines has conducted a survey to determine potential exposure of mine workers to dust produced in connection with intermittent rock drilling in coal mines. Eighteen mines in 3 states were visited, and 30 different operations were observed, as follows: 10 drilling in draw slate, 8 drilling top rock for brushing or grading, 2 drilling in the coal face, 4 drilling in the bottom, 2 drilling top rock for overcasts, 2 drilling in faults or boulders, 1 drilling for roof bolting, and 1 drilling for trolley hangers. Dust respirators were worn by drilling crews during 16 of the 30 operations. Three hundred thirty-two samples of air-borne dust were collected during the survey. ACKNOWLEDGMENTS The information in this report is based on samples collected and observations made in bituminous-coal mines. Operating officials at these mines have contributed to this study, and their cooperation is gratefully acknowledged. All samples were counted by Thomas B. Kirby, chemist, and Dominick A. Ambrosia, scientific aid, and were analyzed by Gretta S. Baur, physicist, and Patricia M. Gussey, scientific aid, of the Health Branch of the Bureau of Mines.

Jan 1, 1953

By S. M. Shelton, W. A. Calhoun

"INTRODUCTION Discovery and development of a southwestern Arkansas quicksilver district are recent history. In July 1930 4/, a specimen was discovered near the Little Missouri River in sec. 1, T. 7S. R. 26 W., which was identified as cinnabar. In the summer of 1931, Leo Yount began prospecting for cinnabar near the Little Missouri River. In the fall of that year he operated a small three-tube retort near the present Parker Hill mines and produced several flasks of quicksilver. Yount optioned a considerable block of ground containing the best showings in the Little Missouri River area, and on February 19, 1932, he and W. C. McBride, Inc., of St. Louis, Mo., formed the Southwestern Quicksilver Co., which was the largest producer in the district until operations ceased in September 1934.The Southwestern Quicksilver Co. installed a rotary furnace on Parker Hill in April 1932, which treated ore from the three principal mines Gap Ridge, Parker Hill, and Parnell Hill. In 1934 production was entirely from the Gap Ridge and Parker Hill mines. Nothing was done at Parnell Hill except a little small-scale work on a share basis.Mercury Producers, Inc., later took an option on the holdings of the Southwestern Quicksilver Co. and in June 1935 began operations. The company produced considerable quicksilver before the lease and option were surrendered in the summer of 1936. Most of the work of Mercury Producers, Inc., was on Parnell Hill, but some work was done on Parker Hill and at the Bell prospect on ground not controlled by the Southwestern Quicksilver Co."

Mar 1, 1942

By Walter E. Lewis

The Fort Randall Reservoir project, on the Missouri River at Pickstown, S. Dak., was designed by the Corps of Engineers and is part of the Missouri River Basin Development Program. The location of the project with respect to adjacent features is shown' in figure 1. When the project is finished, it will include a large earthwork dam and 12 circular tunnels, 8 of which will be equipped for power and 4 for flood control. Various phases of the construction have been contracted to independent companies, and at present four companies are working on different phases of the project under a rigid time schedule. Western Contracting Corp. is the contractor on stage II, earthwork; Johnson-Winston Construction Co. is the contractor for construction of the intake towers at the upstream side of the dam; McCarthy Improvement Co. has the contract for the power house and the outlet works on the downstream side; and Silas Mason Co. has the contract for driving the power and flood-control tunnels. The latter two companies use the same roads for ingress and egress to their respective work areas and the same general waste dump area. Under such circumstances, it is necessary that each company stay on a time schedule in regular sequence to avoid interference with the other.

Jan 1, 1951

By Richard D. Miller

The helium resources base of the United States was estimated by the U.S. Bureau of Mines (Bureau) to be 894.6 Bcf as of January 1, 1989. These resources are divided into four categories in decreasing degree of assurance of their existence: (1) helium in storage and in proved natural gas reserves, 282.4 Bcf, (2) helium in probable natural gas resources, estimated at 237.7 Bcf, (3) helium in possible natural gas resources, estimated at 263.1 Bcf and (4) helium in speculative natural gas resources, estimated at 111.4 Bef. These helium resources are further divided into depleting and nondepleting, with the helium in storage being in a classification. The depleting resources are those associated with natural gasfields that are, or will be produced for the natural gas they contain. Almost all of the helium in potential (probable, possible and speculative) natural gas resources is included in this classification. These depleting resources are estimated to contain 775 Bcf of the total helium resource base. Helium resources contained in nondepleting natural gas resources, i.e., those in shut-in, abandoned, or otherwise nonproducing natural gas fields, are estimated to total 84 Bcf There is 35 Bcf of helium in storage in the Federal Government-owned Cliffside Gasfield near Amarillo, TX.

Jan 1, 1990

By John B. Gayle

The Bureau of Mines has designed and constructed an experimental coke oven, using a commercial oven as a model where practicable. Because the rate of carbonization is important in determining the quality of the coke produced and may affect the "mount of pressure developed during carbonization, particular attention was given to those elements of the design that govern the heat transfer to the charge. The new oven deviates in design from most existing test ovens in that the charge is full width (17 inches), the heating walls ore constructed of 4-1/2-inch silica brick, and zoned, heat-input arrangements compensate for heat losses at the ends, top, and bottom of the charge. This report describes the oven, which was designed by H. S. Auvil and installed under his direction, at the Southern Experiment Station, Tuscaloosa, Ala., while he was supervising, engineer, Coke Section. It gives the results of a limited number of carbonizing tests. These results indicate that the main objective in designing and building this oven, that off duplicating commerical, slot-oven carbonizing conditions, has been accomplished; if coke-discharge conditions simulate commercial-oven conditions, the cokes from the experimental oven arc very similar to oven coke, in soma tests being fully as close is duplicate tests from a Angle batch of coke.

Jan 1, 1952

By Lu Li, Sara E. Wilson

Occupational exposure to whole body vibration has long been associated with increased incidence of low back pain and low back injuries1. A number of studies have investigated transmissibility of seat pan vibration 5, 6. While transmissibility has been well researched, the mechanism by which vibration may induce injury has not been thoroughly studied. Winter et al. identified increased reflex response delay after vibration exposure and speculated that muscular fatigue may be the cause of this increase9. However, a mechanism has yet to be demonstrated completely. A potential mechanism that may explain the increased risk is neuromotor habituation. Muscle spindle organs have been shown in the extremities to be sensitive to muscle and tendon vibration. Rapid length changes in muscle have been shown to result in kinesthetic illusions as the regular firing of the muscle spindles is interpreted as muscle lengthening4, 7. These illusions have also been demonstrated in the paraspinal musculature2. With removal of vibration, research in the extremities has demonstrated increased positioning errors, probably due to neuromotor habituation8. In this research, it has been hypothesized that neuromotor habituation after exposure to occupational vibration will increase positioning errors. It is further hypothesized that these errors can be shown to be linked to increased reflex response time. Such increased reflex response time could, in turn, decrease spinal stability and increase low back injury risk. Methods Both positioning error and sudden load response were measured before and after exposure to 20 minutes of 5 Hz, 0.223 m/s2 RMS seat pan vibration. Subjects were asked to sit on an unpadded seat without a backrest. Throughout the whole body vibration period, subjects were instructed to put their hands on a stable hand rest and feet on an adjustable stable footrest. The subjects were instructed to assume a comfortable and relax sitting posture for the duration of the exposure. Positioning error was measured using an active-active reposition sense protocol. Electromagnetic markers (Motionstar, Ascension Tech, Burlington, VT) were used to track trunk motion. With markers attached to the skin at the T10 vertebra, the S1 vertebra and manubrium, trunk flexion (the angle from vertical of the line connecting T10 and S1) and lumbar curvature (the difference in inclination of the T10 and S1 markers) were tracked. In the reposition sense protocol, subjects were asked to maintain an upright trunk flexion and to rotate their pelvis and lumbar curvature to assume a target lumbar curvature. In the protocol subjects completed training trials, where they were asked to match their lumbar curvature using a visual display, and assessment trials, where they were asked to reproduce the lumbar curvature from memory. After two initial training trials, training trials and assessment trials were alternated for a total of 3 assessment trials. Reposition error was defined as the absolute difference between the target lumbar curvature and the lumbar curvature the subject assumed during the assessment trials.

Jan 6, 2006

This report summarizes the work performed and results achieved on the above contract from October 18, 1971 through July 14, 1972 under Phase II, Task 1: Detailed Design of Prototype and Task 3: Supporting Experimental Investigation. Operation and Service Manuals resulting from Task 3 are submitted under separate cover as are detailed design drawings and specifications, prepared under Task 1. Both items accompany this report. This report also includes (A) an estimate of the cost of construction, (B) a description covering the use of the equipment, and (C) a proposed test plan to demonstrate performance of the equipment in both the laboratory and a mine.

Jan 1, 1972

By Walter D. Holland

This is one of a series of instruction guides developed to help instructors present health and safety training courses to workers in the coal mining industry. This course is intended for training those, usually the safety officers, who perform surveys fur inhalation contaminants in above ground work areas. The handbook entitled ?Handbook for Surveys of Inhalation Contaminants in Above Ground Coal Mining and Processing Work Areas? (NTIS #PB-243-35";) is used as a manual for the course and as a prime reference when performing the actual surveys or interpreting the sampling results. There are six experiments for the students to perform during the course to familiarize them with the sampling devices routinely used during the surveys.

Jan 1, 1976

By Eric R. Bauer

The ground control aspects of extended depth-of-cut mining are presented in this U.S. Bureau of Mines report. A trend analysis of extended cut approvals was performed. A comparative review of roof fall fatalities for extended and nonextended cut mining is included. Current ground control guidelines for extended cut approval are summarized. The problems and concerns of this extraction system are addressed, and typical extended cutting face operations are described.

Jan 1, 1993

By F. D. DeVaney

In the course of the investigation by the U. S. Bureau of Mines and the Missouri School of Mines and Metallurgy at the Mississippi Valley Experiment Station at Rolla, Mo., on the beneficiation of the low-grade manganese ores of the country, some samples from the Cuyuna District, Linn., have been examined. The work was done under the direction of W. H. Coghill, supervising engineer of the Mississippi Valley Experiment Station. Joseph and Kinney in writing about the relative importance of Minnesota deposits of low-grade ore compared to the total reserves say: "***It has been estimated that 26 to 35 million tons of ore contain 5 to 35 per cent of manganese, and the total domestic tonnage is from 75 to 48 million tons. The mean of these values is 30.5 million and 42 million tons, so it is seen that about 75 per cent of the reserves are in Minnesota." The manganese-bearing ores of the Cuyuna district maybe roughly grouped into two classes. The most abundant ore is of the low-silica, low-manganese, and high-phosphorus type called brown are. The other type is the so-called black ore, which is characterized by a higher manganese and silica content and by a lowe phosphorus analysis than the brown ore. As a general rule the brown ore carries less than 10 per cent of manganese while the black ore contains about 15 per cent and sometimes as high as 22 per cent of manganese.

Jan 1, 1930

By W. K. Cunningham, Edwin A. Gee

"INTRODUCTION This paper is one of many reporting on various aspects of the Bureau of Mines program during World War II directed toward alleviation of shortages in certain critical minerals some of these papers are published as technical papers information circulars, and reports of investigations, of the Bureau of Mines or in technical journals.The investigation described in this report was begun as part of the Bureau, of Mines program to develop acid processes for the extraction of alumina from low-grade bauxites and clays. A domestic shortage of high-grade bauxite suitable for treatment by the Bayer process became acute as a result of World War II; and intensive search for a practical acid process using lower-grade alumina-bearing raw materials was therefore warranted.A survey of the various methods for extraction of alumina from clay has been presented in an early Bureau of Mines publication. 4/ The principal barrier to the successful operation of an acid process has been the difficulty experienced in developing a suitable commercial method for purifying the crude aluminum salts after the clay extraction is complete. Iron salts are the foremost contamination influence. A review of the more prominent procedures that have been proposed for separating iron and aluminum salts can be found in the well-known text on aluminum by Edwards, Frary, and Jeffries. 5/The majority of acid processes to extract alumina from clay employ sulfuric acid as the leaching agent, and the purification is thus reduced to the separation of iron and aluminum, sulfates."

Feb 1, 1948

By J. C. Dumbrille

The following account of wining practices of the Kirkland Late Gold twining Co., (Ltd.), at Kirkland Lake, Ontario, is one of 4 series of papers being prepared by the United States Bureau of Mines on mining practices, methods, sad costs in various districts. The author has prepared this paper with the help and permission of J. B. Tyrrell and W. M. Sixt, the managing director and the mine manager, respectively. This mine is operating at a daily rate of about 150 tons.

Jan 1, 1931

By J. D. Warne

The ferberite district of Boulder County, Colo., has been an important producer of tungsten since 1900. During World War I, high prices for tungston concontrates resulted in a brief period of intense activity, and the production in 1917 was 2,707 tons of 60 percent W03 concentrates. Production declined thereafter, and in 19.2 the tungsten produced in Boulder County represented about 4 percent of the Nation's output, being exceeded only by the scheelite production in California, Nevada, and Idaho. Boulder County has boon an important source: of tungsten in the Korean emergency; the present report does not describe this recent activity, as it will be covered by a future publication. Tungsten occurs in small ore shoots of narrow and irregular veins. Most of the ore shoots have been found outcropping on the surface. Core drilling; has been used by the larger operators to explore for new veins and to locate extensions of known veins.

Jan 1, 1953

By E. D. Calvert

The Bureau of Mines, in its effort to promote greater utilization of domestically abundant materials, conducted reasearch on an alternate mold material that has commercial potential for titanium investment casting. Using variations of the conventional lost wax molding process, investment shell molds were formed entirely of fused, calcia-stabilized Zr02 and a Zr02-forming binder. Optimization of binder/slurry properties', stucco grain size and dis¬tribution, and curing practices resulted in a structurally sound investment shell that was distortion free and thermally stable. Small titanium castings, weighing up to 10 pounds, were prepared in unheated molds by both static and centrifugal casting techniques. Microstruc¬tural examination of the castings revealed that mold fill and surface quality were enhanced by centrifugal casting, although good results also were obtained from the statically poured molds. Microstructural and electron microprobe examinations showed that excessive, brittle case formation could be avoided by curing the dried shell molds in air for at least 2 hours at 1,400° C. Increasing curing temperature and time above these levels yielded added bene¬fits. Molds fired in vacuum at 1,500° C for 4 hours yielded castings essen¬tially free of case formation. The tensile properties of as-cast test specimens (no surface conditioning performed) id the chemical composition of representative metal samples showed that castings produced were comparable to Grades C-1 and C-2 unalloyed titanium This indicated that no sifnificant degradation of metal properties resulted from mold/metal interaction.

Jan 1, 1981

By David A. Benjamin

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 24,600-acre Orejana Canyon Wilderness Study Area (OR-001-078), in order to evaluate its identified mineral resources. The study area, located in Harney County, 76 mi northeast of Lakeview, OR, is underlain by Miocene basalt, rhyolite flows, tuffs, and tuffaceous sedimentary rocks. No mines, prospects, or claims were found within the study area. According to the U.S. Bureau of Land Management, the tuffaceous rocks have a moderate favorability for the occurrence of diatomite and a low favorability for zeolite resources. Also, the rhyolite flows have a low favorability for the occurrence of perlite resources. However, U.S. Bureau of Mines' studies indicate that no metallic or nonmetallic resources are present in the study area.

Jan 1, 1987

By William L. Crentz

In a Nation-wide appraisal of coking-coal reserves and of the practicability of upgrading marginal deposits to metallurgical standards, this study of the preparation characteristics of the coals in Cambria County, Pa. , was undertaken. Over 90 percent of the coal remaining in Cambria Comity is found in the Upper Freeport, Lower Freeport, Upper Kittanning, and Lower Kittanning beds. The Middle Kittanning bed, although mined on a commercial scale in the past, is not an important bed now, as most of the remaining reserves are too thin to be mined over wide areas. For many years, Cambria County has been an important source of coal for industrial and metallurgical purposes. The) principal production comes from the Lower Kittanning bed, which accounts for almost .60 percent of the Cambria County coal output. Table 1 shows the county's coal production, by beds, during 1948.

Jan 1, 1950

By Tom Retka

This three volume final report summarizes the activities and conclusions of this contract. The objective of the contract was to develop noise control modifications on a retrofit basis, for auger miner coal-cutting systems. Manuals were prepared to assist mine shop personnel in retrofitting the auger miner with these noise controls. Final Report Volume I - Details all vibration and acoustical tests conducted in develop¬ment of the noise controls. Final Report Volume II - Noise Control Modification Manual for the Jeffrey 100-L Auger Miner describes the various noise control modifications to the auger miner, along with fabrication procedures, cost and vendor information. Final Report Volume III - Noise Control Modification Manual for the Jeffrey 94-L Bridge Conveyor describes the various noise control modifications to the bridge conveyor, along with fabrication procedures, cost and vendor information.

Jan 1, 1978