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By James S. Browning

Domestic production of lithium minerals, source of the lightest metallic element, has increased from an average of 1,327 short tons of concentrate in the 1935-39 period to approximately 37,830 short tons in 1954. This rather phenomenal growth in production and use reflects growing industrial interest in the metal and its salts. This information circular has been prepared to summarize for the casual technical reader the reserve, mining, processing, and consumption situation pertaining to the mineral spodumene - the principal source of lithium. A relatively complete bibliography is included for those who may need more detailed information.

Jan 1, 1958

By J. E. Hamak

This publication contains analyses and related source data for 165 natural gas samples from 21 States and 1 foreign country. Of the total samples, 155 were collected during calendar year 1988. The remainder were collected earlier, but releases granting permission to publish were not received until 1988. All samples were obtained and analyzed as part of U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1989

By S. Gallagher

If we consider ergonomics to be an exercise in matching job demands to worker capabilities, one of the principal capabilities we must be concerned with is that of human strength. Our ability to evaluate different characteristics of muscular strength has increased dramatically over the past couple of decades with the development of new and increasingly sophisticated instrumentation. One would think that armed with such advanced techniques, we might be able to develop methods to conclusively identify workers at risk of injury in physically demanding jobs. Unfortunately, this has not yet proven to be the case. Instead, what these instruments have continued to point out is how intricate a function muscular strength really is, and how complicated and ambiguous its relationship is to musculoskeletal injury. While we cannot just use isolated tests of strength to specify precisely who may be at risk of injury, studies have indicated that strength testing can be a useful tool for job design and, under certain circumstances, selection of workers for demanding jobs. However, because strength is such a complex phenomenon, there has often been some confusion regarding the proper application and interpretation of strength tests in ergonomics, especially among persons not thoroughly familiar with the limitations and caveats associated with the available procedures. The purpose of this chapter is to discuss some of the fundamental principles of strength assessment in ergonomics, so that these procedures can be better applied to control the risk of musculoskeletal disorders in the workplace 1.1. What is Strength? (And what are we Measuring?) Many of the complications associated with strength assessment arise from the simple fact that even our most sophisticated machinery does not directly measure the force or tension developed by a muscle in a living person. Instead, we can only observe the consequences of force development by a contracting muscle, or more likely, by a combination of muscles There are many ways in which we can measure the effects of muscular contraction, and the techniques we use can have a dramatic impact on the strength readings we will obtain. Consider the situation illustrated in Figure 1. In this example, the muscle exerts a constant force of 1000 Newtons (N). However, the forces we measure can vary quite dramatically depending on where we place the force cuff - from 167 N if we place it near the wrist to 500 N if we place it near the elbow. Which value should we select as properly representing the muscular strength for this elbow flexion exertion? The preceding example illustrates some important points with regard to strength assessment. Perhaps the most important is that "muscular strength is what is measured by an instrument" (Kroemer et al. 1999). It should also be clear from this example [ ] that two researchers could perform an elbow flexion strength experiqent on the same group of subjects, but if each selected different force cuff positions, they might end up with wildly differing estimates of strength. Differences in the strengths of various muscle groups in the published literature may be the results of differences in the procedures and measurement methods used by the experimenters Thus, it is critical that any strength data presented be accompanied by a detailed account of the manner in which the data were obtained. A few additional points need to be made with regard to the testing of human strength. We must be clear that what we are obtaining in such tests are not a person's maximal strength capability, but their maximal voluntary strength. The voluntary nature of the exertion introduces an unknown, but surely substantial, amount of variability in our measurements of strength. One can imagine two subjects with identical muscular strength capabilities, but with varying levels of motivation or discomfort tolerance, for example. We are likely to observe considerable differences in the voluntary force exerted by the two, but it should be understood that such results may be largely the result of psychological factors, and not differences m muscular strength per se. The important point to be made here is that not only are we unable to directly measure muscular force, what we are able to measure is modified by an invisible filter - a filter subject to a wide variety of influences and which will differ considerably for every person we test To make matters worse, this filter would be expected to change even within a given individual on a given day. From the foregoing discussion, one can perhaps better appreciate some of the difficulties with establishing a definitive relationship between an individual's measured strength and that individual's risk of injury.

By Harry E. Tuff

"This paper is based data obtained by the Bureau of Mines from some of the principal mine operators in Pennsylvania, in the course of a study conducted in cooperation with the U. S. Forest Service, with regard to economies that might be effected in the selection storage, and preparations of timber particularly treatment with preservative to prolong its life.The Pennsylvania anthracite region, considered as a single mining district is by far the largest user of mine timber of any mining district, either coal or metal, in the United States, and the bituminous districts of Pennsylvania rank second. The present annual consumption of mine timber by the coal-mining industry of Pennsylvania probably exceeds 100,000,000 cubic feet annually.In 1919, Pennsylvania produced, in round figures, 145,300,000 tons of bituminous coal, 86,200,000 tons of anthracite, and 5,400,000 tons of iron ores. If it be assumed that the bituminous coal mines required 0.33 cubic feet, anthracite mines 0.7, and iron mines 0.9 cubic feet per ton mined the timber requirements were bituminous. 47,950,000; anthracite, 60,340,000; iron mines, 4,860,000 or a total of over 113,000,000 cubic feet.The average cost of round mine timber in the anthracite region in 1905, was, according to the U. S. Forest Service, 6.6 cents per cubic foot, and $15.00 per 1000 board feet for sawed timber. The present cost Las advanced to 27.5 cents per cubic foot for round timber, delivered to the mine, of which cost 57.4, represents freight charges."

Nov 1, 1923

By James J. Olson

The Bureau of Mines used micro fracture density analysis of quartz grains in thin sections and diametric pulse velocity measurements along preblast and postblast cores to determine the nature and extent of rock damage produced by small (0.25-,0.50-,1.0-, and 2.0-kg) charges of high intensity explosive (C-4) in granite. Pulse velocities from the postblast cores were significantly lower than velocities from the preblast cores and, with the core logs, provided clear identification of the upper and sometimes the lower limits of most severe damage. These zones ranged from about 1.68 ft for the 0.25-kg blast to 4.16 ft for the 2.0-kg blast. Microfracture densities from postblast cores were significantly higher and more variable than densities measured from preblast cores. The microfracture density measurements showed that microscopic damage was present far past the zones of most severe damage as delineated by the pulse velocity logs and core logs. An exponential relation-ship was observed between the micro fracture density levels and the charge weight.

Jan 1, 1973

By James P. Ulery, Stephen J. Kravits, William P. Diamond

This report presents results of a cooperative research project between the U.S. Bureau of Mines and Beth Energy Mines, Inc. Four coreholes (two before mining and two after mining) were drilled at a longwall mine operating in the Lower Kittanning Coalbed to obtain coal and rock samples from overlying strata to determine their gas content at various times in the mining cycle. The results of those tests indicate that 91 pct of the gas removed from the overlying strata came from coalbeds. Material balance calculations were made to compare the volume of gas produced both from gob gas vent holes drilled on the panel and gas removed by the mine's ventilation system with the volume of gas removed from strata directly overlying the panel to a height of 275 ft. This analysis indicates that only 40 pct of the total gas produced from the panel actually came from the strata directly overlying the panel. The remaining volume of gas production probably migrated to the Iongwall gob from overlying, and perhaps underlying, strata immediately adjacent to the panel and perhaps from greater distances downdip because of the establishment of a long-term pressure gradient in the study area.

Jan 1, 1992

By E. Morrice

The effect of the temperature of SmF3-LiF electrolyte on the electrolytic preparation of samarium-cobalt alloy by the consumable cathode technique was investigated. The temperatures of the cathode zone, alloy collection zone, and samarium oxide (Sm203) feed zone had to be controlled carefully to obtain a satisfactory samarium-cobalt alloy product. Any appreciable deviation from certain temperature values adversely affected yield and product quality.

Jan 1, 1971

By Pablo Velasco

Ecuador had limited mineral output, al-though the Government attempted to stimulate metallic mineral exploration and also evaluated a gypsum and a phosphate deposit. A pilot plant to exploit gold deposits was established, and there was extensive gold exploration activity in southern Ecuador. Domestic output of iron and steel declined sharply. Among all minerals, petroleum output was the dominant factor with both exports and production increasing significantly over that of 1988. Crude oil exports contributed 63% of total export earnings and about 70% of the central Government's revenue.

Jan 1, 1986

By Ray J. Holmquist

"INTRODUCTION The Copper King or Red River copper mine was examined on December 13, 1942, by the Bureau of Mines at the request of Richard Kelly of Santa Fe, N. Mex. The examination was made to determine whether the expenditure of funds for rehabilitation work necessary to make the workings accessible for examination would be warranted.As a favorable report was made, the workings of the Copper King mine were opened and sampled under the direction of the author. The portal of the Copper King adit was opened first. Considerable rehabilitation was necessary in the first 50 feet of the workings, but the remainder of the drifts and crosscuts were sufficiently open to permit surveying and sampling.An attempt was made to open the Waterbury atilt, which was reported to be about 30 feet east of the Copper King portal, and to crosscut the ore body nearly to its southern border. However, slide rock and mine dumps had completely obscured the portal of this adit, and no opening into it could be found or made.Work on the project was started on September 27 and vas completed on November 6, 1943."

Apr 1, 1947

By Northcutt Ely

Jan 1, 1961

By M. H. Kline

The Chestatee mine is one of several well known pyrite deposits in Georgia that are reputed to carry appreciable quantities of copper with the ore. The deposit is? in Lumpkin County on the Chestatee River, 6 miles northeast of Dahlonega (fig. 1). Old records and reports indicated the probable existence of an extensive unmined ore body, but the mine is inaccessible at present. The Bureau of Mines, after studying old maps and records, decided to cor8-drill along the strike of the lense beyond the limits of the indicated old workings in an attempt to extend the possible reserves. The advantageous location of the property indicates that it could become an economic source of pyrite to be used for the manufacture of sulfuric acid. Iron sinter resulting from the roasting of the ores could be sold at a premium in the Birmingham, Ala., area, and the copper content could be extracted to help replace the nation's depleted resources of this metal.

Jan 1, 1949

By J. E. Tiffany, Z. C. Gaugler

"In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 20 and 25 outlining the conditions in use under which, and only under which, the explosive or blasting device is permissible.In view of a recent publication recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 20 and condition 2 on page 25. An explosive or a blasting device enumerated in the permissible lists of this Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.PERMISSIBLE EXPLOSIVES TESTED UNDER SCHEDULE 17CAn active list of permissible explosives was published in October 1938 as part of Bureau of Mines Report of Investigations 3421, under the title ""Active List of Permissible Explosives and. Blasting Devices Approved Prior to June 30, 1938."" This list included 191 brand names.Changes in the list that have been authorized to June 30, 1939, placed 56 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Fifty-seven permissible explosives were transferred from the active to the inactive list. The brand names of four explosives were rescinded curing the year. The present list contains 18G brand names. The brand names of the Permissible explosives placed on the active list are as follows:"

Sep 1, 1939

By Donald I. Kurth

This Bureau of Mines report describes the development and application of a computer model of aquifer hydrology associated with in situ leaching of uranium. The model provides uranium resource developers with a simulation of leachant flow characteristics in a preproduction or pilot five-spot leaching operation. Various types of aquifers are modeled using closed form solutions of the partial differential equations describing the change in fluid head (pressure) as the leaching operation is carried out. User-supplied descriptive input consists of aquifer, well, and leachant flow characteristics. Numeric and graphic outputs such as isopressure, iso-velocity, and isotime contours are available. A typical application is shown.

Jan 1, 1978

"In sum, significant benefits to mine worker health have resulted and should continue to result from the synergistic scientific, engineering, and medical research in respirable dust. As always, an important objective is the rapid dissemination of the results of this research to industry. Video tapes and the Technology News series published by the United States Bureau of Mines (USBM) have been a very effective means of technology transfer. Individual no-cost subscriptions to the Technological News series are available from the Bureau of Mines, Branch of Technology Transfer, 2401 E St., N.W. Washington, DC, 20241.Two respirable dust conferences have been jointly sponsored by the Center, USBM, NIOSH, and MSHA. The proceedings from these conferences are titled:1. Coal Mine Dust Conference held in Morgantown, West Virginia on October 8-10, 1984 and2. Respirable Dust in the Mineral Industries: Health Effects, Characterization and Control held in University Park, Pa. on October 14-16, 1986.Copies of the proceedings from the first conference are available from the National Technical Information Service (NTIS):National Technical Information Service5285 Port Royal RoadSpringfield, VA 22161NTIS # PB86-169380Telephone Number: (703)487-4650Copies of the second conference proceedings, ISBN: 0-936712-76-7 (publication #3010), are available from ACGIH by writing toWilliam D. KelleyExecutive Director, A.C.G.I.H.6500 Glenway Avenue, Building D-FCincinnati, Ohio 45211Telephone Number: (513)661-7881During the period 1984-1987 more than sixty-four (64) papers and publications have been produced by the Center researchers. These publications have appeared in scientific journals and have been presented at national and international symposiums and meetings. A list of these papers, organized by topical headings, has been included in this publication.The generic center maintains a reference center that serves as a clearinghouse for technical information for the generic area and supplies reports on generic center accomplishments."

Nov 1, 1988

By M. J. Friedel, D. E. Scott, T. J. Williams

Rock masses in deep level mines are subject to high stresses, which can result in unexpected failure of rock into mined-out openings. Historically, various independent methods have been used to discern the causes of rock bursts and to evaluate stress conditions in rock masses susceptible to violent failure. Personnel from two research centers of the former U.S. Bureau of Mines, Spokane and Twin Cities, investigated a rock burst that occurred in May of 1994 in a rock mass between the 4400 and the 4600 levels of the Sunshine Mine, Kellogg, ID. The team evaluated the current state of stress in the pillar and the most likely cause of the rock burst by studying the seismic history of the pillar, examining the geology, analyzing the available in situ stress data, calculating possible fault-plane solutions for the burst, and performing a seismic velocity tomographic survey. The results of the study showed that post-rock-burst seismicity was concentrated about 15 to 30 m west of and about 15 m above the rock-burst location. The pillar is composed of a very hard sericitic-to- vitreous quartzite of a type rarely found in the mine, but that is often found in other district mines having a history of seismic activity. In situ stress analysis of the pillar and the surrounding rock mass showed a probable stress rotation from northwest-southeast to east-west. Of four fault plane solutions, the most probable was either a left-lateral, strike-slip movement with a compressive principal stress oriented nearly north-south, or a right-lateral, strike-slip movement oriented east-west. Finally, tomographic images showed low-velocity areas (interpreted as areas of low stress) associated with the crosscuts and haulageways, and high-velocity areas (interpreted as areas of high stress) associated with the rock-burst location. High velocities were also found in a planar area oriented in an elongate northeast-southwest direction.

By J. D. Marchant

As part of its mission to assure the maximum recovery and use of the Nation's mineral resources, the Bureau of Mines, investigated an improved procedure for producing rare earth-silicon alloys. For example, a charge consisting of 681 grams of mixed rare-earth oxides, 309 grams of ferrosilicon (75 wt-pct Si), and 182 grams of aluminum metal along with a flux consisting of 681 grams of CaO and 45 grams of MgO was reacted at 1,500° C in an induction furnace. Good slag-metal separation was achieved. The alloy product contained, in weight-percent, 53 RE, 28 Si, 11 Fe, and 4 Al with a rare earch recovery of 80 pct. In current industrial practice rare earth recoveries are usually about 60 pct in alloy products that contain approximately 30 wt-pct each of rare earths and silicon. Metallurgical evaluations showed the alloys prepared in this investigation to be as effective in controlling the detrimental effect of sulfur in steel and cast iron as the commercial rare earth-silicon-iron alloys presently used in the steel industry.

Jan 1, 1980

Use instantaneous sampling to pinpoint dust sources and to Improve dust control on longwalls. Approach Use a dust monitor developed under a Bureau contract. How It Works Sampling can be done by either a moving or a stationary method. In the "moving' method, the dust monitor is carried by a survey engineer walking at the midpoint of the shearer Dust levels and face position (support number) are taken during all phases of the mining cycle while the shearer is cutting. These measurements can show how changes in airflow along the face, face specific; (rock partings) and cutting sequence (cutting the wedge) variables affect dust levels. In the "stationary sampling" method, the survey engineer stands with the RAM at a fixed location on the face. As the shearer approaches, the dust level and the distance to the shearer are recorded at 10-second intervals. Typically measurements start when the shearer is 20 feet from the sampling position and continue as the shearer passes the position until it is 20 feet away on the other side. Dust profiles around the machine are obtained at several fixed locations along the face only while the shearer is cutting.

Jan 1, 1982

By R. V. Ramani, C. B. Manula, A. Owili-Eger

Network analysis of mine ventilation systems is not new, having been traced back to 1854. A Committee Report (1970) has also reported the extensive work done in this respect in the United Kingdom, Japan, U.S.S.R., South Africa, United States, and other countries. Wang, et al (1970) developed a computer program which is an improvement over the earlier one developed by Wang et al (1967). The program has been recently modified and extended to include methane emission features by Owili-Eger (1973). This computer program incorporates all the novel features of the earlier programs. These include the capabilities of mesh selection, free splitting, internal or external fans, natural ventilation pressure and fixed quantity branches. The program is written in Fortran IV and, in effect, is an experimental mine in which many ideas can be tried out. The computer produces, besides the input data and certain computational data, the quantities and head losses in the branches, the head losses to be adjusted in the fixed quantity branches and the fan operating point. The last named program, hereafter to be referred to as the PSU/MVS, is presented in Appendix I. The application of this program is demonstrated in this manual through a series of selected examples. Application of the methane generator program is not included here as a detailed report on the subject is available elsewhere (Ramani et al, 1975).

Jan 1, 1975

By d&apos, Kathleen J. Amico

THIS SUMMARY is shown in volumes I and III of this series on mineral production in the United States (including Alaska and Hawaii), its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, and on the principal minerals imported into and exported from the United States. For further details on production, see the several commodity and area chapters. A summary table comparing world and U.S. mineral production also is included. [ ]

Jan 1, 1960

By Sean Gallagher, William S. Marras, Alan S. Litsky, Deborah Burr

Background. There is currently little information regarding factors associated with specific modes of motion segment failure using a fatigue failure model. Methods. Thirty-six human lumbar motion segments were fatigue tested using spinal compressive and shear loads that simulated lifting a 9 kg weight in three torso flexion angles (0, 22.5, and 45). Twenty-five segments failed via fatigue prior to the 10,000 cycle maximum. These specimens were visually inspected and dissected so that the mode(s) of failure could be determined.Failure modes included endplate fractures (classified into nine varieties), vertebral body fractures, and/or zygapophysial joint disruption. Logistic regression analyses were performed to determine whether certain morphometric variables, amount of motion segment flexion, disk degeneration scores, and/or loading characteristics were associated with the occurrence of specific failure modes. Findings. Results indicated that stellate endplate fractures were associated with increased posterior shear forces (P < 0.05) and less degenerated discs (P < 0.01). Fractures running laterally across the endplate were associated with motion segments having larger volumes (P < 0.01). Endplate depression was more common in smaller specimens (P < 0.01), as well as those experiencing increased posterior shear force (P < 0.05). Zygapophysial joint damage was more likely to occur in a neutral posture (P < 0.01).Interpretation. These results suggest that prediction of failure modes (e.g., specific endplate fracture patterns) may be possible (atleast for older specimens)