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By Henry P. Chandler

TONNAGE of natural abrasives sold or used in the United States in 1959 increased 12 percent. Artificial abrasives produced in the United States and Canada jumped 24 percent. Imports, exports, and reexports of abrasive materials also showed gains. Sales of grinding wheels were up 33 percent and coated abrasives 17 percent. FOREIGN TRADE Imports of abrasive materials totaled $91 million, an increase of nearly 51 percent over 1958. Chief commodities contributing to [ ]

Jan 1, 1960

By G. E. McElroy

As one phase of a general program of enthracite mine-fire research initiated by the Bureau of Mines in September 1935, a study of the records of past fires was considered a necessary approach to a proper understanding of present and future fires because only limited information could be obtained directly from existing active fires on account of their inaccessibility. Through the courtesy of interested operators, all available records of fires that had occurred in a large group of steep-pitch anthracite mines in the Western Middle and Southern fields of the Pennsylvania anthracite district were examined and analyzed for data on the causes, costs, behavior, and control of fires, and this report is primarily a discussion of these factors based on a close study of these particular records. Mining Conditions The records pertain to a group of mines that have contributed about 12 percent of the total Pennsylvania anthracite production and constitute a large proportion of, and well represent, steep-pitch operations in this district. Throughout the area represented, the coal occurs as a series of up to 20 parallel seams in folded slate and sandstone strata and almost entirely on pitches of 400 to 80°, with vein thicknesses of 5 to 60 feet. Practically all are old mines with histories dating back to 1850, or thereabouts, and present operations are either under or adjacent to mined-out areas extending to surface or to the saddles of anticlines. All operations are at relatively shallow depths, that is, within 1,000 feet, vertically, of the surface. Mining methods are largely a heritage of the past and embrace typical breast and pillar operations with practically no mechanized mining and with the coal shot ?off the solid.? Most of the mines are rated as gassy and are operated now on a closed-light basis. Permissible explosives are now used entirely for breaking coal, and dynamites for rock work and chute-starting blasting.

Jan 1, 1938

By N. Kumar Kittusamy

The purpose of this study was to assess the adequacy of the cab design and to determine the percentage of musculoskeletal symptoms among workers. A questionnaire was designed to assess demographics, work information, job history, and musculoskeletal symptoms in operators of heavy construction equipment. Information concerning equipment included design of the seat/chair, levers, pedals, bothersome vibration, quality of egress from the equipment, proper preventative maintenance and repairs, and age of the equipment. The body regions that were evaluated included the neck, middle/upper back, low-back, shoulder/upper-arm, elbow/forearm, wrist/hand, hip, knee, and ankle/foot. One hundred and eighty nine operators completed the questionnaire. The results indicate that these workers are at risk for developing musculoskeletal disorders, the need to perform a larger survey to further substantiate the outcome, and the need to quantify risk factors (i.e., whole-body vibration and static sitting postures).

Jan 1, 2003

By Alan Mayton, Bertrand Valero, Christopher Jobes, Farid Amirouche

Exposure to vibration induced in and around underground mine’s exploration is a major concern to vehicles operators. Most of these drivers over time develop serious spinal musculoskeletal and discs problems causing low back injuries. The first purpose of this paper is to analyze the performance and dynamic response of driver/operator when subjected to different levels of vibration due to rough road conditions depicted in a mine field. The second purpose of the paper is to quantify the energy transmission in the presence of seat padding with special characteristics and active suspension. Using experimental testing data collected at NIOSH/PRL (National Institute for Occupational Safety and Health/ Pittsburgh Research Laboratory) along with model simulation algorithms developed at the University of Illinois at Chicago we investigated how acceleration transfer functions as well as absorbed power affects the different parts of the body. To this end, we used a previously validated human model which includes the head, torso segments and legs. The connective forces between body segments were modeled through modal analysis techniques from previous experimental data at the UIC Vehicle Technology Laboratory. The absorbed power and energy transmitted to the body are used as an index measure to assess the viability of the different seat padding’s and active seat suspension control strategies.

By F. Keith Shelton

"INTRODUCTION Cobalt is an essential metal in the normal industrial ac¬tivity of the United States. Being an important constituent of high-speed steels and other cutting-tool materials, it becomes of critically essential importance during periods of national emergency. 3/ The Presidential order of December 20, 1940, included cobalt among other essential commodities that could be exported only under license. The Executive order 4/ listed cobalt metal, cobalt oxide, and alloys containing more than 5 per¬cent cobalt as being within the licensing requirements.There was no domestic marketed production of, cobalt products from 1931 until 1940 when the Pyrites Co. 5/ produced some cobalt oxide. The major portion of the domestic cobalt requirements has been obtained from Northern Rhodesia, the Belgian Congo, and French Morocco. 6/ The uncertainty of sea transportation from those sources of supply demanded that steps be taken to obtain from domestic raw materials an adequate supply of cobalt for use in the materials required for production of indispensable machined war metal products. In connection with the national policy for attaining self-sufficiency of strategic and critical materials, the Bureau of Mines, Boulder City, Nev., Experiment Station initiated studies to recover cobalt from the low-grade oxidized cobalt deposits in the Goodsprings district, Nevada. Hewett 7/ reported occurrence of cobalt specifically in the Blue Jay, Columbia, Copper Chief, and Highline mines and generally over a widespread area in the district."

Jan 1, 1946

By J. Fletcher Smoak

Consumption of abrasive materials in the United States increased 22% in value over that of 1982 to $320 million; of which, 59% was manufactured abrasive, 35% was industrial diamond (natural and synthetic), and 6% was natural abrasive. Production value of natural abrasives, excluding industrial diamond, remained virtually unchanged. Production of crude tripol, a porous siliceous rock, decreased slightly; however, shipments of processed tripoli increased 13% in quantity and 32% in value. Production of garnet, an abundant iron-aluminum silicate, continued to increase primarily because of further increases in production from one plant that had completed an expansion program in late 1981. Production of special silica stone, both crude and finished, decreased in 1983 because of reduced demand for oilstones

Jan 1, 1984

By Alvin Schallis

The. problem of supplying enough magnesia for the American war effort has become highly important. Before hostilities began, only about two-thirds of our, require vents came from domestic sources; now they must supply almost all the magnesia we need. A further burden is placed upon our own supply by the fact that more and more magnesia is being required, not alone to pace the war tempo of general industrial activity, but also to replace chrome ore in refractories and to make magnesium metal. The domestic magnesite and brucite industry is equipping itself to satisfy much of this greater demand for magnesia, but the remainder must be obtained elsewhere. The principal sources of magnesia are magnesite, brucite, dolomite or high-magnesium limestone, natural brines, sea water, salt-works bitterns, magnesium silicates, and magnesium salts. Although dolomite is tae subject of this paper, it should be considered in perspective with all these highly competitive sources of magnesia.

Jan 1, 1943

By Douglas D. Reynolds

Intense vibration can be transmitted to the hands and arms of workers who use hand-held percussive or vibrating devices, tools, and work pieces. Continued habitual exposure to vibration directed to the hands can cause patterns of various symptoms associated with hand-arm vibration syndrome (HVAS). The International Organization for Standardization (ISO) first published ISO 5349 in 1986.3 This standard specified methods for measuring and evaluating vibration directed into the hands from hand-held vibrating devices, tools, and work pieces. The American National Standards Institute (ANSI) published ANSI S3.34 the same year.1 This standard was modeled after ISO 5349-1986 and specified methods for assessing exposure to hand-arm vibration. The Parliament of the European Union has issued the European Union Human Vibration Directive-2002/44/EC, which specifies vibration daily exposure action values (DEAV) of 2.5 m/s2 and daily exposure limit values (DELV) of 5.0 m/s2. These values have generally been accepted by medical experts, scientists, and engineers in governmental agencies, research institutions, and industry in the USA and other countries.2 When they are achieved, they will reduce the potential for the development of symptoms related to HAVS among workers exposed to hand-arm vibration. Significant improvements in measurement and analysis instrumentation, miniature and subminiature accelerometers, and medical diagnostic and assessment protocols have being introduced since 1986 when ANSI S3.34 was first published. In response to these improvements and the introduction of the EU Human Vibration Directive, ANSI Working Group S2.39 developed the revision to ANSI S3.34, which has now been published as ANSI S2.70-2006.2 Method ANSI S2.70 specifies the use of the hand-arm vibration measurement procedures outlined in ISO 5349, Parts 1 and 2.2,4,5 It requires the measurement of ISO frequency-weighted acceleration values in three mutually orthogonal axes of vibration. These values are then vectorially added to obtain the vibration total value, ahv: [ ] where ahwx, ahwy, and ahwz are the measured r.m.s. ISO frequency-weighted acceleration values in the x, y, and z directions, respectively. If multiple vibration exposure events are experienced during a work day, the overall vibration total value is obtained from: [ ] where ahvi is the vibration total value of the ith operation, Ti is time duration in hours of the ith operation, n is the total number of operations, and T is total time in hours associated with the n

Jan 6, 2006

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

Underground coal mine tracked vehicles have been studied to determine the state of the art and how brakes might be added to the coal haulage cars. Specific areas of interest are: brake sys terns, couplers, car trucks and car handling procedures. Problems related to adding brakes to the haulage cars appear to be: the limited amount of room to mount the brakes on the cars, brake line connection between rotary dump cars, achieving desirable braking characteristics without over complicating the system and keeping the installation cost to a reasonable figure. This document combines the information contained in the first issue of the "State-of -the-Art of Underground Coal Mine Tracked Vehicle Brake Systems," BRL Report No. 6080, with that contained in a subsequent monthly report.

Jan 1, 1973

By Joel N. Van Sant

An investigation was conducted to study possible sources of Utah refractory and structural clays that could be used for the manufacture of refractories and light or buff burning heavy-clay products. A field study was made and the clay samples tested to determine their firing characteristics. Results of the Bureau's work indicate many small noncommercial deposits of hypogenic clay occur in igneous rocks. Commercial hypogenic deposits are mostly halloysite clay developed by hydrothermal replacement of limestone. The high firing shrinkage of halloysite precludes its use as a refractory, however, halloysite produced at the Dragon Mine south of Eureka, is used fur making oil catalysts. Clays and shales suitable for low heat duty refractory products are found in the Manning Canyon shale, in shales associated with coal bearing rocks, and in the Dakota formation. Some of the clays from the Dakota formation are also suitable for high-duty refractory products.

Jan 1, 1964

By Sean Gallagher

The vast majority of ergonomics research has addressed the demands of work in standing or sitting postures, and understandably so. However, many workers (for example, underground miners, aircraft baggage handlers, plumbers, agricultural workers, mechanics, and others) are often required to adopt postures such as kneeling, stooping, squatting, or lying down for significant periods of the work day.

Jan 1, 2005

By O. C. Blade

"INTRODUCTION This report on the properties of motor fuels sold through service stations in the United States is a continuation of a series of reports made in accordance with a cooperative agreement between, the Coordinating Fuel Research (C.F.R.) Committee of the Coordinating Research Council (C.R.C.) 3/ and the Bureau of Mines of the United States Department of the Interior. The first of these reports presented data on motor gasolines sold during the winter of 1935-36.-4/ Further reports have been issued describing motor gasolines sold during the succeeding summers and winters to the summer of 1941 and during the winter of 1942-43 and the summer of 1943 5/ No reports were made on motor gasolines sold during the winter of 1,) 41-42 and during the summer of 1942. The present report presents analytical data for 1,356 samples, representing the products of approximately 103 companies. As in previous surveys, the companies covered by the survey include both large and small suppliers. Conforming to former reports, the data cover three groups of samples - regular-price, premium-price, and third-grade gasolines - and each group has been averaged separately. The number of samples, items and brands comprising each group is as follows: Regular-price, 770 samples, 286 items, and 94 brands; premium-price, 537 samples, 236 items, and 72 brands; third-grade, 49 samples, 31 items, and 18 brands. The meanings of these terms as used in the surveys are as follows:"

May 1, 1944

By Charles E. McCarthy, MORTON T. PAWEL, E. A. GEE, FRANK S. RIORDAN

Large tonnages of the magnesium silicate mineral , olivine, are known to exist in the mountains of western North Carolina and in the Puget Sound region of Washington. The North Carolina deposits alone are reputed to contain at least 230 million tons of ore averaging 45 to 49 percent of magnesium oxide In both areas the mineral is readily accessible and can be mined by the simplest methods ; one of the largest of the Washington deposits is located at tidewater .

Sep 1, 1946

By Joan Weinberg

Real gross national produce (GNP) grew at a seasonally adjusted annual rate of 2.0% in the fourth quarter (table 1). The restrained quarterly growth rate was the slowest in 2 years, and was substantially slower than the 2.5 % rate of the previous quarter. According to the U.S. Department of Commerce, the summer drought reduced the fourth-quarter growth rate by 1.1 percentage points. A growing trade deficit and a reduction in business investment were the key economic factors curtailing growth. The trade deficit widened by $6.8 billion, reflecting both a surge of imports and a slowing of exports. Business investment declined 3.7%, mainly as a result of a slowdown in computer sales. On a year-to-year basis, the economy grew at an inflation-adjusted rate of 3.8% for 1988, the fastest in 4 years, despite the drought. However, on a fourth-quarter-to-fourth-quarter basis, real growth measured 2.7%. Increased exports and business spending for plant and equipment accounted for much of the 1988 GNP growth. Employment continued to grow as the manufacturing sector added 414,000 new workers (table 2). Of these, the primary metals industry added 26,000 workers, and the clay, glass, and stone industry added 10,000. The civilian unemployment rate remained low throughout 1988, fluctuating between 5.3% and 5.4% during the last quarter.

Jan 1, 1989

Anaconda Aluminum Co. began production from a new 60,000-ton-per-year potline at Sebree, KY, which brings the total capacity of the plant to 180,000 tons per year. A strike by workers at Alcan Aluminium Corp. primary aluminum smelters at Arvida, Que., Isle Maligne, Que., and Beauharnois, Que. shut down the plants and the company announced force majeure on part of its ingot supply commitments. Kaiser Aluminum and Chemical Corp. announced plans to increase its price for primary aluminum from 60.0 cents per pound to 63.0 cents per pound effective July 1.

Jan 1, 1979

By D. E. Andrus

This paper, which describes the milling practice at the Montana mine concentrator of the Eagle-Picher Lead Co., is one of a series being prepared by the United Slates Bureau of Mines. LOCATION The Montana mine is situated on the eastern edge of the Oro Blanco mountains at an elevation of 4,300 feet. It is in the Oro Blanco mining district, Santa Cruz County, in the southern part of Arizona, about 4 miles north of the Mexican border, 30 miles northwest of Nogales and 80 miles southwest of Tucson. Amado, a station on the Southern Pacific Railroad, midway between Tucson and Nogales, and about 40 miles northeast of the mine, is the shipping point and is reached over an excellent highway.

Jan 1, 1931

By D. E. Wolfson

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report The inherent suitability of coal for metallurgical purposes depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, Be well as the amount of available reserves, are considered in selecting coals for carbonization tests. The selection of coal beds in Harlan County, Ky., for coking tests was based, in part, on recent studies of coal reserves by Wallace,3/ who estimated the recoverable reserves in beds 28 inches or more thick, in tons, as follows:

Jan 1, 1956

The value of U.S. mineral raw material output reached a record $63.1 billion in 1975. This high exceeded the 1974 value of $55.2 billion by 14 percent. Among the three major mineral categories -fuels, metals, and nonmetals -only fuels showed an increase in value. Both the metal and nonmetal categories showed declines in value. The significance of this nearly $63 billion mineral output can be noted in the fact that it is the basis for the subsequent production of over $270 billion a year in energy and processed materials. Of the 78 individual mineral commodities included in these 1975 totals, only 17 registered gains in output, while 45 registered value increases, reflecting higher prices.

Jan 1, 1976

During fiscal year 1966 the Bureau of Mines published 99 scientific and technical papers and engaged in 67 research projects on petroleum, natural gas, and oil shale. A basic appropriation of $3.4 million was supplemented by $1 million in cooperative funds from other Governmental agencies and industry groups. Petroleum conservation was advanced by development of scientific knowledge and improvement of technologic methods in both the extraction and utilization of petroleum, natural gas, and oil shale. Experimental work was carried out at research centers in Bartlesville, Okla., and Laramie, Wo., and in laboratories in Morgantown, W. Va., and San Francisco, Calif. ACHIEVEMENTS IN FISCAL YEAR 1966 Bureau of Mines--Petroleum Research in fiscal year 1966 (July 1, 1965- June 30, 1966) was involved in many public issues--air pollution, peaceful uses of nuclear explosives, utilization of oil-shale resources, computerization of recovery-stimulation techniques, and fuels for supersonic airplanes. Scientific contributions included compositional studies of petroleum and oil shale, determination of thermodynamic properties of petroleum compounds, development of analytical techniques, and correlations of petroleum properties with geologic occurrence. Technologic advances included rock-fracturing research, in situ combustion studies, waterflood techniques, use of radio-tracers to study stability of petroleum fuels, and hydrogenation as a tool to prepare shale-oil products.

Jan 1, 1968