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By Friedel. Michael J.

The U.S. Bureau of Mines investigated acoustic emission (AE) and the Kaiser effect in six types of rock: St. Cloud gray granodiorite, Barre granite, Dresser basalt, Salem limestone, Berea sandstone, and a volcanic tuff. AE signatures were used for interpreting the rock deformation stage and for indicating mechanisms of failure in uniaxial compression. The research demonstrated the advantages of using the volumetric stress-strain curve, as opposed to the more conventional uniaxial curve, for correlating AE response signatures with deformation stages and fracture processes in the rock. Standardized experimental procedures were used for the AE monitoring. The Kaiser effect was shown to be capable of determining prestress levels to within a few percentage points in uniaxial compression tests. Also, prestress memory was shown to be retained in the rock for periods of up to at least. 5 months, the maximum period of testing. The Kaiser effect AE technology holds promise for providing a comparatively inexpensive and less complex method for examihing stress history in rock. However, since the conftning stress has a pronounced influence on the Kaiser effect, it must be considered in developing technology for determining peak fteld stresses based on the Kaiser effect.

Jan 1, 1990

By W. M. Traver

During World War II, the Bureau of Mines investigated a large number of ore deposits in the United States and Alaska in a search for domestic sources of strategic minerals. Deposits chosen for exploration included those expected to contain metals of importance in the successful prosecution of the war. This report describes exploration of a district of known antimony occurrence on Coyote or Antimony Creek near Antimony, Garfield County, Utah. A preliminary report by Paul T. Allsman, Chief of the Bureau's Salt Lake City branch made in August 1941, recommended further investigation, and proposed methods for performing the work. The project, begun in November 1941 and completed in January 1942, included trenching and sampling in four of the most promising parts of the area The Federal Geological Survey cooperated in the work by detailed mapping and assisted in the interpretation of geologic data.

Jan 1, 1949

Pillar design is the first line of defense against rock falls—the greatest single safety hazard faced by underground coal miners in the United States and abroad. To help advance the state of the art in this fundamental mining science, the National Institute for Occupational Safety and Health organized the Second International Workshop on Coal Pillar Mechanics and Design. The workshop was held in Vail, CO, on June 6,1999, in association with the 37th U.S. Rock Mechanics Symposium. The proceedings include 15 papers from leading ground control specialists in the United States, Canada, Australia, the United Kingdom, and the Republic of South Africa. The papers address the entire range of issues associated with coal pillars and have a decidedly practical flavor. Topics include numerical modeling, empirical design formulas based on case histories, field measurements, and post failure mechanics.

Jan 5, 1999

By R. Michael Digman

Few efforts have been undertaken to date to assess the quality of mandated coal mine health and safety training for new miners and for experienced miners. This study was concerned with the quality and effectiveness of existing classroom health and safety training programs. The study involved field data collection through pre- and posttesting of trainees, audio-taping class sessions, and administering short feedback forms with trainers and trainees at 14 sites in West Virginia, Maryland, Kentucky, and Pennsylvania. Results indicate that goals, methods, materials, and outcomes of existing training programs vary widely among trainers and sites. The report provides less by way of solution to problems, than it highlights the breadth of issues that relate to the question of training effectiveness and quality. The report concludes that additional work by industry, labor, government, and academia is necessary in order to improve health and safety training programs. Recommended steps are: (a) to develop performance standards and measurable criteria in each of the types of mandated training, (b) to develop better training of trainers, (c) to develop expanded training support services. and (d) to undertake further research and development in health and safety training in the mining industry

Jan 1, 1982

By T. H. Miller

This piper is a continuation of a series of yearly review articles started in 1925 by Thomas Varley. The development of flotation has been rapid, and better understanding of the functions o' flotation reagents has resulted in many changes in the kinds and quantities o reagents used. It is the purpose of this report to present the information in such a manner as to be of value to the milling industry as well as to the manufacturer of flotation reagents. These data have been compiled from a. survey of approximately 250 flotation plants of all classes within the United States. Many of these plants made complete reports of their operations, out others were apparently unable to supply this information in sufficient detail to meet the requirements of this investigation. Although it is realized that the data obtained in this survey are not as full as they should be to render the greatest service possible to the milling industry, it is hoped that succeeding articles will include complete information regarding milling; conditions and recoveries. As in the past, every effort has been made to conceal individual plant operations. RESULTS OF INVESTIGATION Table 1 gives the tons of ore treated by gravity and flotation methods and the concentrates produced as reported by 208 plants. The totals of 77,043,535 tons of ore and 4, 596,640 tons of concentrates from this table compare with totals of 78,973,012 tons and 4,683,972 tons respectively (furnished by the Bureau of Mines, Division of Mineral Statistics), indicating that the milling survey is about 98 per cant complete.

Jan 1, 1930

By A. U. Miller

For many years Illinois has been one of the leading coal producers in the United States and as such its safety record has compared very well with the other large coal producing States , both in tons produced and millions of man -hours of exposure per fatal accident . ( See Table 25 in Bureau of Mines Bulletin 293. ) During the 10-year period from 1917 to 1926 , inclusive , the average production in the United States per fatal accident was 278 , 109 tons . The aver age for the State of Illinois for the same period was 409,249 tons . Illinois produced 450,464 tons per fatal accident, and in 1928 produced 390,630, tons , or an average of 419,721 tons for the 12- year period from 1917 to 1928 , inclusive . In 1927 During the year 1929 , the shipping mines of the State made a decided improvement in their record over any previous year . Table 1 shows the monthly production and the tons produced per fatal accident . During 1928 and 1929 safety work was actively carried on in Illinois . Safety meetings were held with mine officials , representatives of the State. De partment of Mines , and the United States Bureau of Mines . At these meetings mine hazards and accidents were discussed and remedies suggested for : their elimination in the future . It is believed that first - aid training was to a considerable extent instrumental in reducing accidents and in making the good safety records in Illinois during 1928 and 1929. During these years ( as well as in 1926 and 1927 to a somewhat less extont ) en intensive rirst-aid training campaign was con ducted in Illinois by the officials and members of the United Mine Workers of America , coal companies, State Department of Mines and Minerals , and the U. S. Bureau of Mines , Every first -aid class was made a safety meeting ; where accidents and general safety were discussed freely while teaching first aid. During this time , anproximately 25,000 persons were trained in first aid, and 17 coal companies were issued certificates for having 100 per cent of their employees. trained in first aid. Since January 1 , 1926 , more than 40,000 have received first -aid training in and around Illinois mines , and including those who received training previous to this date , it is believed that at least 90 per cent of the miners in Illinois have received first -aid training . This state ment is based on the fact that the labor turnover in Illinois is not large .

Apr 1, 1931

By D. S. Burgess

An investigation of the hazard of spillage of liquefied natural gas (LNG) onto water is described. About 2,000 gallons of LNG were consumed in various tests. The initial vaporization rate of LNG following spillage was found to be 0.037 lb/ft2 sec; when the spill was confined, this vaporization rate was moderated after about 20 seconds by the growth of an ice layer on the water surface; when the spill was unconfined, a coherent ice floe was not observed and the vaporization rate was essentially time independent. The maximum diameter (in feet) of the spreading LNG pool was found to be given by 6.25 Wo 1/3, where Wo is the weight of LNG in pounds, Downwind of a natural gas source, time-averaged methane concentrations were given in good approximation by standard air pollution equations. However, peak concentrations were as much as twentyfold higher than average, adding an additional factor to the assessment of hazard. The effect of layering by the cold vaporized natural gas was similar to the effect of a temperature inversion on normal gases in the atmosphere. Small-scale explosions were observed on pouring LNG onto a water surface; no single explanation seems pertinent to all of the incidents observed.

Jan 1, 1970

By A. W. Deurbrouck

The separations achieved by eight conventional cyclone washers have been evaluated to determine their performance when processing intermediate size coal of 28 mesh bottom size. The dense-medium cyclones provided efficient, sharp separations in treating feeds of up to 44 percent of near-gravity material at separating specific gravities ranging from 1.42 to 1,55 (one separation of a secondary feed was made at 1.63). Complete washability analyses are shown by sizes of the composite feed to these cyclones. The magnetite losses per ton of coal processed ranged from 0.6 to 2.0 pounds; however, of the eight plants reporting losses, seven indicated magnetite losses were 1.1 pounds or less per ton of coal processed.

Jan 1, 1972

By Roy L. Grant

The Bureau of Mines investigated the up-and-down method with factorial designs to determine if shorter, and therefore less costly, trial sequences could be used. Although sequences of 50 trials are usually recommended, sequences of 20 trials were arbitrarily chosen for the experiments with permissible coal mine explosives described in this report. These explosives were fired from a cannon pointed into a flammable natural gas-air atmosphere at the Bureau of Mines Explosives Research Center gallery to ascertain their safety properties. The investigation demonstrated that the shorter sequences led to useful conclusions with a reduction in cost of the experimental program.

Jan 1, 1967

By Thomas C. Atchison, Joseph M. Pugliese

Six explosives were compared by measuring their strain- producing abilities in limestone . Peak strain , e , varied with scaled distance , R/Ro , according to the following equation : € = Kc (R /R 。)- ". The distance exponent , n , was a constant of the rock and did not depend upon explosive . The strain intercept , Ke , increased with increasing detonation pressure of the explosive . The strain intercept also depended upon the explosive- to - rock impedance ratio . For impedance ratios from 0.53 to 1.38 , the strain intercept was approximately proportional to the medium stress , Pn , as calculated from the explosive detonation pressure , P , and the explosive - torock impedence ratio , Z , by the simple elastic theory relation : P = 2P / ( 1 + Z ) . PD However , the data indicated that , at lower values of impedance ratio , the strain intercept is relatively larger than would be expected from the simple elastic theory . The results presented provide a simple method for predicting the relative effectiveness of different explosives in breaking limestone from the detonation pressures and characteristic impedances of the explosives .

Jan 1, 1964

By A. C. Fieldner

In the course of its investigations on the properties of coal and in rendering fuel-inspection service to other agencies of the Government, the Bureau of Mines has accumulated a comprehensive file of coal analyses that includes data on virtually every coal field of commercial importance in the United States. As knowledge of the composition of coal is potentially valuable to every user of coal, the Bureau publishes its analytical records. Before 1921 such publications contained analyses of coal from all parts of the United States; individual analyses or average analyses of a series of shipments of coal were given with the name and location of the mine producing the coal. Beginning in 1921 the analyses were published by separate States because the quantity of data had become so great. The separate papers published to date, with Bureau of Mines Technical Paper numbers, are as follows: Alabama, 347; Arkansas, 416; Colorado, 574; Illinois, 634 and 641; Indiana, 417; Iowa, 269; Kansas, 455; Kentucky, 30S; Maryland, 465; Missouri, 366; Montana, 529; New Mexico, 569; Ohio, 344; Oklahoma, 411 ; Pennsylvania (bituminous), 590; Tennessee, 356; Utah, 345; Virginia, 365; Washington, 491 and 618 (618, published in 1941, supplements 491); West Virginia, 405 and 626; and Wyoming, 484. From time to time the various papers will be revised to include later analyses and other data. The Bureau of Mines annually receives many inquiries as to the composition of coals obtained from specific localities or, conversely, as to the localities from which a given kind of coal may be obtained. This paper presents a summary, in tabular form, of the composition of commercial coal resources of the country. Specimen analyses are given exemplifying the analysis of coal mined in each coal-producing county, or, where it was feasible, coal from each bed in each county; also, ranges of analyses, within which the composition of most of the coal represented will fall, are given where there were enough analyses to permit satisfactory determination of the ranges. In addition, the degree of metamorphism from lignite toward anthracite of much of the coal is indicated by the classification by rank. This classification reveals to more experienced users of coal some of the general properties of coal, that is, whether the flame will be long or short, whether the coal will cake in the fire, and how it is likely to behave on exposure and in storage.

Jan 1, 1942

By Van H. Manning

The term war minerals has been applied t.o those ores and minerals that were largely imported. before the war. Among the mon important of these are manganese, essential for making high-grade steel for munitions and industrial use; graphite, for u,.akin1 crucibles; tin, for plating utAmsils and for bearing-met.al; mereury, used as fulminate t.o explode shells; pot.uh, for making fertilizer and explosives; tungsten and molybdenum, for high-speed t.ool steel; antimony, for hardening bul!et lead; chromite, for tool steel, for tan- , ning leather, and as a refractory lining in furnaces; magnesite, for :refract:A>ry linings; mica, as insulating material; platinum, for the manufacture of sulphuric acid and for electrical apparatus. When the United States entered the war it was clear that every ship would be needed and that the number available for importing minerals would be small. Hence a quick and thorough survey of domestic resources was necessary. . Throughout the war the scope and volume of the war-minerals work increased until it covered practically every mineral that was known t.o be or was liable to be in short supply.

Jan 1, 1919

By T. C. Campbell

This Bureau of Mines publication presents an analysis of information related to the transportation of bituminous coal by unit trains and slurry pipelines. Even for short hauls from mines to markets, transport costs frequently account for between one-third and one-half of the delivered price of coal. Minimizing these costs has become an even more critical objective for hauls from the western mines than for hauls from farther east. Factors related to minimizing costs and transporting the western coal receive special attention. Although no general rule of preference is likely to be developed that can be applied to all shipments, both rail and pipeline service will be needed on an increasing scale. The study should provide useful background information and analysis for government and industry in approaching investment decisions in the mining and transportation industries.

Jan 1, 1975

By Frederick W. Lee

List of contributing editors of Geophysical Abstracts:

Sep 1, 1932

By Suresh K. Bhatt

Although overall worker productivity for U.S. underground coal mines is available, productivity by mining method and seam thickness is not. Mining technology has gone through dramatic changes in the past decade, and the industry has experienced a lack of accurate productivity Figures addressing these changes. This information is of great interest in planning for future mining systems as thick and shallow coal seams currently being mined are depleted and exploitation of thinner, deeper, and better quality seams is considered to partially meet the requirements of the 1990 Clean Air Act Amendments. In a cooperative program, the U.S. Bureau of Mines obtained raw mine level production and related data from U.S. Energy Information Administration for 1989 and 1990 and performed the needed statistical analysis. Base criteria, parameters, and salient results of the mine productivity analysis are presented in this report.

Jan 1, 1994

By V. A. Nieberlein

The purpose of this investigation is to determine the reserves of columbium (niobium) minerals in Arkansas and to develop metallurgical methods for concentrating the minerals and extracting the metal. The columbium resources of central Arkansas were explored by drilling and trenching, and a number of samples were taken. On the basis of this exploration the known reserves of the metal were estimated to be over 78,000,000 pounds. The reserves could possibly be extended by additional exploration to 150,000,000 pounds.

Jan 1, 1954

By D. Randolph Berry

The U.S. Bureau of Mines awarded a contract to Foster-Miller Associates, Inc. (FMA) to provide recommendations on the safest, most practical methods for complying with new regulations requiring that all underground coal miners have a self-contained, self-rescuer (SCSR) -a device capable of supplying, in an emergency, 1 hr of self-contained oxygen (no breathing of mine air). This report develops information and recommendations which could be used during the early stages of nationwide compliance, especially in the areas of inspection, testing, and underground storage of SCSRs. Volume I contains an Executive Summary, Introduction, Definitions, Recommended Guidelines for District Managers and Mine Operators, and a Storage Plan Checklist and Sample Form.

Jan 1, 1981

By James H. Gary

Data regarding the composition and physical properties of Florida land-pebble phosphate-waste slime are presented, and the feasibility of dewatering and beneficiating the slime by several different methods is discussed. Chemical analyses, electron micrographs, and X-ray diffraction data showed that principal constituents of the slime included quartz, attapulgite, and flaorapatite. Viscosity of the slime changed with pH; thixotropic, Newtonian, and rheopectic states were observed as the pH increased. Use of various flocculating agents was not effective in improving thickening properties of the slime. Dewatering tests using pressure filtration showed that temperature influenced the filtration rate more than pressure; the filtration rate at 165° C was tenfold that at room temperature. Selective flotation of the slime, using two different processes, gave promising results. About 25 pct of the phosphate was recovered in a concentrate assaying 31 pct P205, Other tests demonstrated that the slime could be successfully fractionated at 20-microns using a hydrocyclone. In hydrometallurgical tests about 80 pct of the phosphorus and alumina were chemically extracted from the slime using sulfuric acid. Limited bacteriological studies made of the slime showed that several types of microorganisms were present and grew in the material despite the presence of fluorine-bearing minerals.

Jan 1, 1963

By C. Thomas Hillman

This Bureau of Mines report describes an investigation of factors influencing economic viability of a proposed system to mine and process manganese nodules. The system consists of hydraulic dredging and ammonia leach processing designed to recover three metals: nickel, copper, and cobalt. A ferromanganese recovery plant is a considered option. Annual capacity is 3 million dry metric tons (t) nodules. Aftertax rates of return (ROR's) of only 7.38 and 6.63 pct are predicted for three-and four-metal base scenarios, respectively. Sensitivity analyses indicate that variations in commodity prices, metal recoveries, and deposit grades produce similar incremental changes in ROR. Estimated cumulative effects of price variations are greatest. While three-metal operations generally yield higher predicted returns, potential increases in manganese price and process recovery could make four-metal operations most profitable. Maximum variations in both capital costs and three-metal operating costs result in ROR changes of about 25 pct. In contrast, four-metal ROR's exhibit variations to 70 pct. Even so only a best case analysis, utilizing favorable variations in all categories tested, generated ROR's approaching a level thought necessary to trigger company interest. Consequently, it is concluded that nodule mining will not take place in the foreseeable future without significant financial incentives.

Jan 1, 1985

By J. M. Mutmansky, C. Lee

"Measurement of the size and elemental characteristics was performed on airborne coal mine dust samples collected by multi-stage cascade impactors as well as channel samples of the geologic materials. Size distributions were obtained using precise weighing techniques on the impactor substrates. Elemental analysis on the samples was performed by the proton-induced x-ray emission (PIXE) method, a rapid and non-destructive method of multi-element analysis.The various analyses were performed on 9 major and 21 trace elements. The results indicate the importance of intake air and shuttle car movements as sources of dust. The association of coal dust characteristics with channel samples was investigated using the coefficient of proportional similarity as a statistical measure. Results show a strong relationship between major elements and the geologic material being cut but a similar relationship between trace elements and geologic materials is not consistent.1. INTRODUCTIONThe most significant occupational disease in the coal industry is known ·as coal workers' pneumoconiosis (CW'P). While CW'P has existed for centuries, its mechanism of occurrence and association with coal dust has been well understood for only a few decades. In the 1930s, the significance of this disease led state and government officials in the USA to perform extensive epidemiological and environmental studies in the major coalfields. Study of these results plus later studies in the coal producing countries of Europe eventually led to the dust regulations that appear in the Federal Coal Mine Health and Safety Act of 1969.The impacts of the 1969 act were a productivity decline and increased production cost. Many analysts attributed this in large part to difficulties in complying with the new dust standards (Brezovic 1981). However, compliance was met in most continuous miner sections rather quickly. The remaining problem area is that of longwall mining where the procedures and layout of the minin~ system make it difficult to meet the standards."

Jan 1, 1989