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By Stephenson. E. L.

"INTRODUCTION In the spring of 1942 a series of magnetometer surveys on deposits of black sand underlying Pleistocene raised marine terraces along the coast of southwestern Oregon was nada by the Division of Geophysical Exploration of the Federal Bureau of Mines in cooperation with the Oregon Department of Geology and Mineral Industries. A few preliminary tests had been made in the same area in May 1940 and December 1941.The sands contain fine gold and metals of the platinum group, and, beginning in 1852, extensive, but spasmodic mining and exploration have been done for these precious metals. There are many old placer, mines and prospects, although for the most part the yield of the metals has been small. The sands also contain other minerals of potential value, including ilmenite, magnetite, garnet, zircon, and particularly chromite, and the wartime demand for domestic chromite resulted in extensive testing and development of the known deposits. The purpose of the magnetometer surveys was to determine the efficacy of, magnetic methods in tracing and outlining these known deposits and in prospecting for new ones. The field work was done between March 17 and May 29, 1942, by the author assisted by W.W. Paulsen of the Oregon Department of Geology and Mineral Industries."

Jun 1, 1945

By Louis H. Berkelhamer

"INTRODUCTION ""Free silica"" includes all free forms of silicon dioxide, such as quartz, chalcedony, tridymite, cristbbalite, opal, diatomaceous earth, and lechatelierite. The term, has been used rather loosely however, as synonymous with quartz, as quartz is the most abundant form of free silica. ""Combined silica,"" on the other hand, has been reserved to denote silica combined with other elements as silicates.Improvements in methods for the determination of free silica, and quartz in particular, have been the subject of considerable interest during the past decade, owing mainly to the accented and increased knowledge concerning quartz as a causative factor in silicosis. Analysis for quartz, however, is of importance in many other fields, including the determination of quartz in ceramic raw materials, such as feldspar and clay; the evaluation of a beneficiation procedure by the ore dresser, such as in the concentration of iron ore; control studies of a manufactured product, such as silica brick; and routine analysis of rock, mineral, and ore samples by chemists and petrographers."

Jul 1, 1944

By Paul W. Jeran, Michael A. Trevits, William P. Diamond

In this U.S. Bureau of Mines study, production trends have been analyzed for 82 gob gas ventholes on 7 longwall panels in the Lower Kittanning Coalbed, Pennsylvania. Cumulative production from individual holes was found to vary considerably, ranging from 0.03 x 106 to 10.1 x 106 m3. Peak production rates were generally about 0.03 x 106 to 0.06 x 106 m3/d, but rates over 0.10 x 1@ m3/d were observed. The variability of gas production from individual holes can be attributed to several factors, including completion practices and problems, the extent of fracture development in the strata above the extracted panel, water production, and location on the panel. Of particular significance is hole location. Holes on the ends of the panels, where overburden strata are in tension because of the support of the surrounding pillars, were generally the highest and longest producers. This observation led to the experimental placement of gob gas ventholes in the zone of tension along the margin of a panel, instead of in the traditional centerline location, which is in compression. Analysis of 7 months of gas production data indicates that the experimental near-margin holes produced 77 pct more gas than did centerline holes on the same panel.

Jan 1, 1994

By S. T. Reese

STATISTICS of injuries in the quarrying and related industries in the United States first became available when the Bureau of Mines collected reports from the operating companies for the calendar year 1911. Since then reports have been collected annually. The present bulletin, covering the calendar year 1952, is the 33d publication containing statistical data on injuries at quarries and related plants, and it is the first to be published since 1944. The last publication was Bulletin 458, Quarry Accidents in the United States during the Calendar Year 1942. The unpublished statistics for 1942-51 may be found in the Appendix of this bulletin. The Bureau of Mines is authorized to collect data on injuries at quarries, but there is no Federal law that compels operators to supply such data, and the reports received from operators are voluntary responses to the Bureau's requests for information. Although the figures presented herein may not be complete for the entire industry, every effort has been exerted to make them so, and the figures given are believed to be thoroughly representative of the hazards to which quarry workers are exposed. Moreover, the figures are com¬parable as between States -which is significant in view of the lack of uniformity among the States as regards classes of plants covered by State laws, classes of injuries covered by State reports, and other factors that tend to make it impracticable or impossible to compare the injury experience of one State with that of another or to comprehend the relative importance of the various causes of injuries in the industry as a whole.

Jan 1, 1955

By Nancy Estrada, Jane Nowell, Cathy Jennings, Debra Yniguez, Carol Lavery, Kristin Harrer

Pilots of the MH-60S helicopter are exposed to continuous whole body vibration (WBV). Pilot fatigue is a growing operational concern due to the increased frequency of extended durations of missions (6-8+hours) in support of Operations Iraqi Freedom and Enduring Freedom. Endurance aspects of the currently used rotary wing seating systems were not optimized for the longer missions and wide range of pilot anthropometric measurements, which is now typical of naval aviation. The current seating systems were designed primarily to meet crashworthiness requirements, not for the wide range of pilot anthropometry or to mitigate WBV. Albeit, an issue, pilot fatigue and reduced mission effectiveness are also critical concerns. Current Hazard Reports indicated that pain in pilots’ legs and backs begin two to four hours into the flight and increase with time. Mission readiness also decreases with an increase in flight duration due to the constant distraction of pilots shifting in their seats while trying to get comfortable. Froom, et al [2] reported a dose-response relationship between the length of military helicopter flights and back discomfort. He also concluded that this pain is typically dull, over the lower back, and its prevalence and intensity are dependent on the total flight hours of exposure. Methods This study evaluated WBV produced in the pilot seating systems onboard the MH-60S. The purpose of the study was to test and compare the effectiveness of two different seat cushions, the current seat cushion versus an anti-vibration seat cushion. Both seat cushions were measured for acceleration levels averaged over five-minute intervals using a triaxial seat pad accelerometer. The recordings were completed for a 3-hour straight and level flight. A frequency analysis from 0-80 hertz (Hz) was conducted on all acceleration measurements to determine the dominant axis and frequency of the pilots’ vibration exposure. The results were then compared to the applicable Threshold Limit Values (TLVs) established by the American Conference of Governmental Industrial Hygienists (ACGIH) [1] and the International Organization for Standardization (ISO) 2631.1 [3] to determine the MH-60S pilots’ permissible exposure time for both seat cushions. Results The results of the study showed that for both seat cushions the vibration levels of the z-axis at 16 Hz had the shortest allowable exposure duration, according to the ACGIH TLVs. In the z-axis at 16 Hz, the MH-60S’s current seat cushion’s acceleration levels indicated an exposure time limit of approximately 6 hours, while the anti-vibration seat cushion’s acceleration levels pierced the 8-hour exposure time limit curve. This is shown in the graph below.

Jan 6, 2006

By John A. Kost

Previous work performed under Contract H0220003 suggested that the mean incombustible content could be obtained with fewer samples and smaller samples without greatly increasing the sampling error. Under Modification No. 4 additional surveys were made in twelve coal mines, representing six states. Same 2,500 samples were collected, analyzed for incombustible content, and statistically evaluated. The earlier findings were substantiated.

Jan 1, 1975

By Oliver Bowles

Granites are classed as igneous rooks; they have been formed by the solidification of rook magmas or Solutions from deep within the earth. It is an almost invariable law of nature that mamas which cool quickly form fine-brained or glassy rocks, while those that cool slowly are completely crystallized and are coarser-grained. Granites, being of the latter class, are regarded as having attained their solid form at considerable depth below the surface under conditions of high temperature and pressure. The constituent minerals crystallized out slowly, the crystals interlocking with one another. The great depth of overlying rocks that must have been present when crystallization took place has been removed by erosion over large areas on the surface of the earth in consequence of which granites appear at or near the surface in many localities.

Jan 1, 1930

Now more than ever, the United States must have an adequate and dependable supply of minerals to meet its defense and economic needs. A chief mission of the U.S. Department of the Interior Bureau of Mines is to help ensure that the United States meets these needs at acceptable environmental, energy, and economic costs. As it looks toward the 21st century, the Bureau of Mines will focus its attention on the following areas: - upgrading the capabilities of its mineral information and analysis program - expanding mineral land assessment activities - disseminating the practical results of federally funded research activities to the private sector through enhanced technology transfer - addressing the impact of regulations on mineral industries - addressing the needs for mineral-oriented training and research in the Nation's universities - enhancing mine worker health and safety - improving mining and mineral processing productivity through automation, robotics and other innovative technologies - reducing the environmental impact of mining and mineral processing operations - and enhancing the accessibility and conservation of domestic mineral resources.

Jan 1, 1991

By A. F. Robertson

"INTRODUCTION This report is supplemental to R.I. 4178 and deals with the work accomplished between June 15, 1945, and September 7, 1945, on the Mitchell-Hodge mine, Grady mine, Albea and York property, and Cuzzort property.ACKNOWLEDGMENTSIn its program or exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources 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 exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurigcal Branch, O. C. Ralston, chief, analyzes samples and performs benefication tests.Acknowledgment is due Mitchell H. Kline, chief, Raleigh Division, Mining Branch; Abraham L. Fox, acting chief, Raleigh Division, Metallurgical Branch; and Rowe McCrae, district engineers, U.S. Bureau of Mines, Gainesville,"

Jan 1, 1946

By E. Chin

The countries of Asia and the Pacific have large resources of diverse minerals. Australia and China have extensive mineralization that are commercially being exploited. The major minerals in Australia with known reserves adequate for both domestic demand and export markets include bauxite, clays, copper, diamond, gold, iron ore, lead, manganese, mineral sands (titanium minerals), nickel, salt, silver, tin, uranium, and zinc. China is the world leader in proven reserves of antimony, barite, magnesite, molybdenum, rare earths, titanium (ilmenite), tungsten, and vanadium. It also has about 55 billion tons of iron ore, albeit with an average grade of only 30 % to 35 % elemental iron content. With the exception of chromium and copper, China has significant resources of a wide array of minerals and metals, based on its production and/or export capability for these commodities. Additionally, India has significant resources of bauxite and mineral sands; Indonesia, bauxite, copper, nickel, and tin; Malaysia, tin and associated titanium; Mongolia, copper, fluorspar, and lead-zinc; New Caledonia, nickel; New Zealand, gold and iron sand; North Korea, magnesite; Papua New Guinea, copper, gold and mineral sands; Philippines, copper, chromite, and gold; and Sri Lanka, gemstones. Moreover, there appears to be extensive mineralization III Burma (Myanmar), Cambodia, Laos, Thailand, and Vietnam, but they have yet to be definitively delineated.

Jan 1, 1994

By David Schlain

IN 1942 the Bureau of Mines began to develop the Kroll process for use in the large-scale production of titanium. Titanium and titanium alloys are now commercial metals. These metals are relatively expensive, but It is now evident that they will have important industrial uses and that in many instances these will be related to their remarkable corrosion resistance. This bulletin presents the known corrosion properties of titanium and its alloys in useful form. In marine environments titanium is highly resistant to corrosion and does not pit, or undergo crevice corrosion, stress corrosion, or corrosion fatigue. Titanium is also highly resistant in many salt solutions, including most chlorides. It is very resistant to corrosion in nitric acid solutions. It is also resistant to white fuming nitric acid. However, it may react violently with red fuming nitric acid. In phosphoric acid solutions titanium has rela¬tively good resistance to corrosion, but it has less resistance to sulfuric acid and still less to hydrochloric acid solutions. Titanium corrodes very rapidly in hydrofluoric acid Solutions. It is very resistant to corrosion in many organic chemicals. However, it has only moderate resistance to formic acid solutions and poor resistance inn oxalic acid solutions. Titanium does not corrode in dichloroaretic acid but, corrodes rapidly in 100 percent trichloroacetic acid at 100° C. Titanium is resistant to barium, calcium, magnesium, ammonium, and sodium hydroxides. Titanium is inert in wet chlorine, bromine, or iodine gases. However, in dry chlorine gas titanium reacts rapidly enough to ignite. It also reacts rapidly with dry bromine gas, but, it is resistant to dry iodine gas. When titanium is exposed to red fuming nitric acid solutions with high nitrogen dioxide content and low water content, it corrodes, undergoes stress-corrosion cracking, and becomes pyrophoric. This occurs more readily with some titanium alleys, such as titanium-8 percent manganese. A fresh titanium surface immersed in water or in an aqueous solution and in contact with an oxygen-rich atmosphere under sufficientt pressure is unstable and will ignite spontaneously. Inherently an active metal, titanium has a tendency to become less active in environments containing oxidizing agents such as air, oxygen, chlorine, or ferric, cupric, or platinic ions. Titanium is more noble than most structural metals in roost, environments and its excellent corrosion resistance is generally not, affected by contact with these metals. However, some of the other metals corrode faster because of contact with titanium. Titanium undergoes anodic polarization readily, so that even when it is the less noble member of a galvanic couple it may corrode less because of the contact. Titanium alloys often have corrosion properties and electrochemical characteristics similar to those of commercially pure titanium. Titanium alloys containing noble metals, zirconium, molybdenum, vanadium, tantalum, or copper sometimes have better corrosion resistance than pure titanium.

Jan 1, 1964

By Michel C. Frippel

This section of the Minerals Yearbook reviews the minerals industries of 27 countries: the 12 nations of the European Community (Belgium, Dermark/Greenland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain, and the United Kingdom); 6 of the 7 nations of the European Free Trade Association (Austria, Finland, Iceland, Norway, Switzerland, and Sweden); Malta; the 8 Eastern European economies in transition (Albania, Bulgaria, Czechoslovakia, Hungary, Poland, Romania, and Yugoslavia); and the U.S.S.R. Western Europe Western Europe [loosely defined to include the 12 nations of the European Community (EC) and the 7 nations of the European Free Trade Association (EFTA)] is the single largest trading area and consumer of raw materials in the world. If Western Europe was at one time an important mining sector, it has now increasingly relegated the role of supplying minerals for its minerals processing industry to the more minerally endowed countries in North and South America, Africa, and Australia. In this regard, Western Europe is the most important determinant of raw materials consumption (and thus, indirectly, raw materials production). Western Europe has significant reserves of industrial minerals but has limited availability of metalliferous raw materials. It, therefore, imports significant quantities of the latter and ranks along with the United States and the U.S.S.R. in the production of refined metals. Nonetheless, there is an inherent tendency to underestimate the importance of Western Europe in the world of minerals, both as a minerals processor and raw materials buyer. The reason for this is that Western Europe is generally thought of on the basis of individual nations rather than as a whole. Viewed in this limited context, the United States, the U.S.S.R., and Japan appear to dominate the world economy. Viewed as one regional area, however, Western Europe includes the fourth (FRG), fifth (France), sixth (United Kingdom) and seventh (Italy) largest economies of the world, all bordering on one another. With the remaining 15 EC and EFTA countries, Western Europe has a land area approximately 40 % of that of the United States, exceeds the U.S. population by 50 % and has a gross domestic product about the same as that of the United States.

Jan 1, 1993

By Leon W. Dupuy

Marquette's first reported the existence of iron In Missouri in 1673. Recorded production wan begun in 1815, increasing in size and importance until 1888, when the low price of iron resulting from Minnesota's production of high-grade ore caused most of the operators to close down. Missouri's iron production came from three types of ore: (l) Brown ores, including the deposits of primary and secondary limonites in southeast and southwest Missouri, (2) hematites of the filled sinks, including the ores of Central Ozark district, and (3) specular ores in porphyry, including the deposits of the St. Francois Mountains.

Jan 1, 1949

The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment; including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that are recommended in this document, but all of the panic bars are characteristically of the ?fire door? type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they are required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in "Guidelines for the Design and Installation of Devices for Deenergization of Self -Propelled Electric Face Equipment/Automatic Emergency Brake s II by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel at the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By Charles L. Kimbell

In overall aggregate, the world's mineral industry in 1987 experienced a more satisfactory year than in 1986, at least insofar as its performance could be assessed from traditional statistical indicators. Production, trade and consumption seemingly advanced in the case of the majority of commodities, and prices for a number of commodities advanced. It was by no means certain, however, whether 1987 investment in mineral industry ventures would top the levels of 1986, when, in the case of petroleum industry investment expenditures there had been a sharp decline, this in contrast to evidences of a slight upturn in steel industry investment. World crude mineral output value was estimated at more than $1,084 billion, and the value added by minerals industry processing of this material probably raised the total value of the industry's production from primary materials to more than $2,600 billion constant 1983 dollars. Less easy too assess was the value of mineral commodities moving in international trade, but with a resurgence in oil prices from the 1986 levels, an increase above the 1986 $500 billion mark seemed assured. There are no comprehensive aggregate statistics on mineral consumption comparable to those on production and trade, but quantitative growth recorded for most major commodities suggested a favorable trend, particularly when coupled with a general (though by no means universal) upturn in unit prices.

Jan 1, 1989

By Edward L. McHugh

The study area, which comprises 28,443 acres within the Jacumba Wilderness Study Area, is in the California Desert Conservation Area, and along the U.S.-Mexico border 25 miles west of Fl Centro, CA. The U.S. Bureau of Mines evaluation of mineral resources is based on examination of mining claims, known mineral occurrences, and mineralized zones during the fall of 1983. Limestone resources were identified inside the study area; tungsten resources may he present. Metasedimentary rocks intruded by Cretaceous Quartz diorite predominate in the study area. Tungsten and some gold have been found in skarn zones along intrusive contacts; limestone deposits are in the pre-Cretaceous rocks. Tertiary and Quaternary volcanic flows, pyroclastic rocks, clay beds, and diatomite in lake deposits nave been investigated for possible non-metallic resources. Evidence of mining or prospecting was found at 26 sites in or just outside the study area. In 1983, 106 claims were held in 13 claim groups. One claimant was sporadically prospecting for gold on claims in the north part of the study area in 1983, and gravel was being mined from alluvium 1/4 mile to the east.

Jan 1, 1985

By L. A. Conley

This report, covering the period January through December 1976, contains abstracts of articles related to cost engineering and economics for chemical and petroleum plants, mining, and other mineral industries from the following periodicals: 1. Air Pollution Control Association Journal 2. Chemical Engineering 3. Chemical Engineering Journal 4. Chemtech 5. Coal Age 6. Coal Mining and Processing 7. Combustion 8. Drilling-DCW 9. Electrical World 10. Engineering and Mining Journal

Jan 1, 1977

By L. R. Herrmann

The research described in this report is the first phase of a comprehensive program for the development of a characterization for the structural properties of rock masses. The mathematical expression of the characterization is especial' tailored for use in conjunction with modern structural analysis procedures. The objective of the first phase of the project is to determine the feasibility of representing the structural properties of rock masses in terms of the analysis of an appropriate "representative volume" the results of this investigation are described in detail in the body of the report. The current state-of-the-art concerning the understanding and description of the fundamental mechanisms of rock behavior are determined from a survey of existing literature. The development of a representative volume that captures the most important of these mechanisms is described, In order not to unduly obscure the fundamental aspects of this development, the mathematical analysis of the representative volume is limited to plane strain conditions. A subroutine for the numerical evaluation of the proposed model (i.e., the analysis of the representative volume) is presented. The steps necessary for the incorporation of the subroutine directly into existing two-dimensional finite element structural analysis programs are described. Comparisons between the predictions of the proposed characterization and published results of simple laboratory tests are presented and discussed. Finally recommendations are given concerning suggested improvements of the model and the extension of it to the general three-dimensional case.

Jan 1, 1974

By Jeffery L. Kohler

This final report on Bureau of Mines Contract J0338028 presents the results of a research effort to predict incipient failure in electric-power-system components. The development of continuous monitoring techniques to detect an incipient failure would represent a significant improvement in system maintainability, availability and safety, This report describes the analytical and experimental aspects of the project. Mathematical models have been developed to study the behavior of cables and motors which are undergoing a deterioration process. These models allow a detailed study of the effect of deterioration on the component's terminal characteristics and performance. The efficacy of using negative-sequence monitoring is a reliable indication of deterioration has been established. Techniques for assessing the sensitivity of the prediction algorithm to component deterioration have been presented. An approach for modelling electrically-excited vibrations, and including these in the algorithm, has been presented.

Jan 1, 1987

By NEFE AEWFW

Changes in the 1980 quantity and value of the sales of various natural abrasives, compared with the data for 1979, were of a mixed nature. Output of garnet and special silica stone products increased in both tonnage and value during the year, while emery and tripoli-type materials production decreased in both tonnage and value. The reported quantity and value of sales of manufactured abrasive material-fused alumina and alumina-zirconia, silicon car-bidet and metallic iron and steel shot and grit-also decreased for 1980. [ ]

Jan 1, 1981