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By P. C. McWilliams

The Bureau of Mines investigated ground support problems in four major block-cave mines to assess the current "state-of-the-art" and to delineate areas for future research. The most significant problem is the inability of present support systems to hold moving ground. Further, as mining progresses to greater depth, this problem becomes more serious. Providing adequate temporary support capable of withstanding primary and secondary blasting is the next most significant problem. A detailed analysis of the effect of mining methods on support problems is also recommended for future research.

Jan 1, 1975

By J. S. Walker

The Bureau of Mines monitored surface subsidence and water level fluctuations in 10 shallow observation wells above a series of four adjacent longwall panels in southwestern Pennsylvania, for about 4 yr. This study attempted to correlate the changes in the water levels within the observation wells to the measured vertical and horizontal ground movements associated with subsidence. Results of this study indicate that the fluctuation of the water levels appears to be a function of the well location relative to the mine layout and the proximity of mining. Wells are generally unaffected by mining of a preceding panel unless they are located within the angle of draw for that panel. Wells located at the centerline of a longwall panel exhibit the greatest fluctuation and head loss. This relationship may be related to the strain developed by the advancing longwall face. The water levels in the wells monitored fell at the greatest rate when the ground surrounding the well was in tension. The rate of the decline decreased as the dynamic development of the strains was changing from tension to compression. The water levels were found to be near the premining level before the ground was subject to maximum compressive strain. Nine of the ten wells investigated recovered to their premining water level after mining was completed.

Jan 1, 1988

By Charles K. Rose

The Cebolla Creek titaniferous iron deposits near Powderhorn in southern Gunnison County, Colo., were examined by the Federal Bureau of Mines as part of an overall program to investigate the Nation's titanium and iron resources. The deposits occur around the periphery of the Iron Hill stock, which underlies an area of about 12 square miles. Concentrations of magnetite, ilmenite, and perovskite arc localized along fractures in the pyroxenite stock. Mineralogical studies of composite surface samples collected in 1956 showed that most of the iron is present in ilmenite-bearing magnetite. Perovskite is the chief titanium mineral in the magnetite-rich and augite-rich types, and sphene is the principal titanium mineral in the placer material. The mica-rich rock contains approximately equal amounts of perovskite, ilmenite, and sphene.

Jan 1, 1960

By H. L. Burmeister

This report describes the mining and milling practices used by the Eastern Magnesia Talc Co. at its Johnson, Vt., operation. The report also contains a description of the local geology and all available information on cost and performance data. Since 1925 the mine has produced continuously at an average annual rate of 54,000 tons, and the ratio of ore hoisted to finished product is roughly 2 to 1. Ore is stoped by a combination of shrinkage and sublevel methods. In any 24-hour period the mill produces an average total of 14 grades of finished talc product, 9 by dry grinding and air classification and 5 by wet grinding and flotation methods. The mine operates one shift per day, 5 days per week and the mill operates on a 3-shift, 5-1/2-day-per-week basis. Operating costs for 1958, on a percentage basis, were mining, 22.34; milling, 54.77; ore haulage, 2.89; and all other, 20.00 percent.

Jan 1, 1963

By W. F. M. GOSS

The locomotives in service on the railroads of this country consume more than one-fifth of the total coal production of the United States. The amount is so large that any small saving that can be made effective in locomotive practice at once becomes an important factor in conserving the fuel supply of the nation. For this reason the United States Geological Survey gave attEmtion to the special problems of combustion in locomotive boilers. It approached this task from several different directions. The facts presented herewith constitute one series of results. In the fall of 1906 the locomotive-testing laboratory of Purdue University, at Lafayette, Ind., entered on a series of tests, one purpose of which was to determine in precise terms the degree of efficiency with which a modern high-class American locomotive utilizes the heat energy of the fuel supplied to it. The general interest in the subject, the elaborate plans which had been formulated for conducting the work, and the substantial character of the support which had been pledged to maintain it justified the Geological Survey in aiding the investigation. a The cooperation of the Survey consisted in detailing experts to assist the regular staff of the laboratory in the chemical and calorific work of the tests. These experts, working under the general supervision of the director of the Purdue laboratory, became responsible for the sampling of smoke-box gases, of the fuel used, of the cinders caught in the front end, of the sparks discharged by the stack, and of the refuse caught in the ash pan. The gas analyses were made by them at the university laboratory. The analyses of all solid samples and the calorific tests of the fuels were made at the government fuel-testing plant at St. Louis. The representatives of the Survey were not concerned with other phases of the work.

Jan 1, 1911

By Clarence Karr

RESINS from a bituminous pitch, a bituminous coal, a lignite tar, a subbituminous pitch, and an electrode binder pitch wore investigated by the Bureau of Mines. The compositions of these resins were determined by four independent methods of structural detemination: (1) Molecular formula and ring analysis, including ring (2) infrared and ultraviolet spectra; (3) combined pyrolysis/gas chromatography, and (4) catalytic dehyrogenation followed by spectra and pyrolysis. The resin structure was correlated with coal structure, and it was concluded that pitch resins probably consist of essentially unaltered coal molecules carried over with the tar vapors in low-temperature carbonization.

Jan 1, 1966

By Doris M. Hyde

The petroleum sector continued to dominate Ecuador's economic activity in 1978, accounting for nearly 10% of the gross domestic product (GDP) and 42% of total export earnings. In 1978, a more flexible petroleum export price was adopted which permitted an expansion of foreign market opportunities. During 1979, Ecuador took advantage of disruptions in the world petroleum supply and renegotiated existing export contracts to accomodate the rapidly escalating world market price. Petroleum sales on the spot market were maximized, and prices reached unprecedented levels. By taking royalty payments in-kind, Ecuador increased its volume of petroleum available for term and spot sales. Although the volume remained about the same as in 1978, the total value of 1979 petroleum exports increased to about $920 million, reflecting a 76% increase over the $523 million received for 1978 crude oil exports. Concerned about its steadily decreasing petroleum reserves (recently estimated at about 1.1 billion barrels), rapidly increasing and heavily subsidized domestic consumption, and the prospect of having to import substantial amounts of petroleum by 1983, Ecuador announced plane which it anticipates will double reserves within the next 5 years. The Government plans to spend $1 billion over the 5-year period. Plans include drilling 325 exploration and development wells and establishment of a secondary recovery program for the Sachs and shushufindi fields. Some exploration wells are expected to reach a depth of 17,000 feet. It is thought that substantial reserves exist in the southeast Amazon region. Late in 1979, it was announced that some 10 million hectares will be available for exploration tenders-probably in blocks of about 200,000 hectares each-in the Amazon jungle of the Orients and in the coastal and offshore regions. The Government planned to commission a private, independent analysis of Ecuador's petroleum reserves that would also include recommendations on efficient production levels.

Jan 1, 1981

By J. O. Lewis

"The significant facts in the problem of the relation between the production of crude petroleum, and the ever-increasing demand for petroleum products are that in spite of continually increasing production, improvements in methods of refining and utilization, and heavy increases in imports, demands grow still more rapidly and we seem always faced with a shortage at hand or lust ahead. On the other hand, our foremost authorities warn um of entirely inadequate domestic reserves. Looking abroad we find some large fields and many of speculative promise, 'tut the situation is complicated by international relations and demands by other countries which promise to be even more insistent than oars. This is the situation, then. We can not rely upon our own Crude Petroleum to meet the Ever Increasing Demand for Petroleum Products.I wish to follow this somewhat alarming statement by saying at once that the Bureau of Mines is not pessimistic in facing this situation. To my mind those who discuss the oil situation may be placed in three categories; the pessimists, the optimists, and the super-optimists. The pessimists I call those who see darkly and will concede no possibility of solution. According to them a few years will see the automobiles piled in windrows of 'dilapidated junk, I have no sympathy with this point of view and deem it vicious and entirely unwarranted.The optimists I term those who believe that there is a solution and that we shall be able to meet all of our reasonable requirements for as far into the future as can be foreseen, yet who recognizes that this desired end can not be attained without prevision and energetic effort.The super-optimists are those who will say to you, ""There is nothing to this talk of shortage, whenever we have needed oil we have always found it and always will."" To these gentlemen the possibility of an inadequate supply of oil is as incomprehensible as the possibility of the extinction of the passenger pigeon was to the early settlers who saw flocks that hid the sun for days during their passage. The passenger pigeon disappeared within two generations thereafter, and I deem this point of view as being perhaps more vicious than that of the extreme pessimist. It seems to me it is nothing less than improvidence lulling us into a false sense of security. There is an old proverb to the effect that ""The Lord helps him who helps himself."" I believe that we shall solve the oil problem, but I do not think it will be solved by vague optimism. It is going to call for our most energetic efforts and I believe we shall have to do a lot of ""helping ourselves."""

Oct 1, 1920

By R. V. Ramani, R. Bhaskar

"The National Academy of Sciences (1) recognized the importance of studying the spatial and temporal characteristics of respirable coal mine dust atmospheres. In this paper, the progress to date of a research project on dust transportation and deposition in mine airways is presented. A mathematical model is proposed for studying the transport of dust. A source representative of dust generation in underground coal mining is defined. The influence and applicability of surface roughness, dispersivities, coagulation and reentrainment to vine dust flow arc examined. A convective-diffusion model is proposed for the transport and deposition of dust in mine airways. Using the model, the spatial and temporal characteristics can be evaluated in terms of dust concentrations in the mine atmospheres.INTRODUCTIONThe prediction of the behavior of fine particles Is Important in many fields of science and engi¬neering including physics, chemistry, mining, mineral processing, and atmospheric science. In mining from the health point of view, fine coal dust is associated with the appearance of pneumoconiosis in miners exposed to the dust. Also, in addition to being a nuisance factor obscuring visibility and general mobility of miners, it can lead to sudden catastrophic incidences of explosions. This paper outlines the progress to date of a research project on dust transportation and deposition in mine airways. A mathematical model is proposed for studying the transport of dust for the various mechanisms. The dust dispersion is defined in terms of a dispersion term determined from experimental data by Skubunov (23). Coagulation is considered as one of the mechanisms that can lead to changes in the particle size distribution. Reentrainment as a possible secondary source of dust was examined during model development but was not included in the final model."

Jan 1, 1988

By Juel H. Stears

Research was done to determine if a hydraulically operated penetrometer developed by the Bureau of Mines could be used to estimate the roof-bolt anchorage capacity of mine roof rock. Tests were conducted both in the laboratory using cement cylinders and underground in shale rock. Hardness readings were measured by the penetrometer around the periphery of the bolt holes at the anchorage horizon. Roof bolts Nere then installed and subjected to an anchorage test. The results showed that the penetrometer readings could be used to determine the optimum stratum for roof-bolt anchorage but could not be used to make an accurate estimate of the anchorage capacity.

Jan 1, 1965

By Thomas O. Llewellyn

This U.S. Bureau of Mines (US8M) report presents a concise review on sources, processes, supply, and historical use patterns of domestic cadmium. It also covers a preliminary estimated cadmium material balance for the year 1989.

Jan 1, 1992

By M. M. Myers

"Importance pf the small stone problem.Profitable disposal of limestone too small for making lime in the shaft kiln, is one of the most urgent problems in the lime industry. Reports received by the Bureau of Mines from 31 quarries show that the proportion of small stone varies from 2 to 40 per cent, averaging 18 per cent of gross pro¬duction, Modern methods of heavy blasting, and the use of crushers in large quarries tend to increase the proportion of small stone above that produced in early days when light blasting and hand sledging were almost universally used. There is also a growing movement toward underground operation of lime deposits, a method which in general produces a greater proportion of fines than is encountered in open-pit work. Thus the small stone problem is of growing importance, and demands the attention of every progressive lime producer. As the problem is of almost universal interest, it is urgently desired that every operator who reads this report will contribute from his knowledge or experience, answers to the questions on the final sheet.There are several markets in which small stone may be sold but in these markets the competition is generally keen and the prices low. The lime producer's chief product is lime, he understands its manufacture and marketing, and brings him a greater return than can be obtained from most limestone by-products. For these reasons it is evident that the conversion of small into lime is the nest desirable means of disposal."

Apr 1, 1924

By J. Hyvarinen, A. D. Look

"INTRODUCTION AND SUMMARYElectricity is used extensively in open-pit metal mines to provide illumination, heat, and power to operate hauling and loading equipment, drills, pumps, signal systems, and other machinery. Good installation and maintenance of equipment and power, circuits, are essential to minimize the hazards of shock, burns, and fire.In the 13 years from 1931 to 1943, 20 fatal and 82 nonfatal injuries resulted from the use of electricity in open-pit mines in the United States ; 4/ these figures represent about, 10 percent of all fatalities and 1 percent of the nonfatal injuries. The ratio of fatal to nonfatal injuries from electricity in such mines was very high during this period; the figures show one fatality to every five accidents from this cause.Electricity may cause personal injury through abnormalities in equipment, such as short-circuit, accidental ground, overload, and poor contact; however, each year some fatal electrical accidents are due to persons touching uninsulated ""live wires."" These contact injuries are the result of careless body movements of persons in the vicinity of 'wires at places not normally frequented, or of accidental contact with live circuits when handling metal objects. Electrical hazards can be minimized by the enclosure or elevation of current-carrying parts; ample working space around equipment, adequate insulation, locking switches in the open or closed position under certain conditions, identifying and warning devices, protective grounding, insulating flooring, platforms, or rubber gloves, and proper inspection and maintenance."

Apr 1, 1949

By Kenneth G. Skinner, Hewitt Wilson, Thomas L. Hurst

Although chromite deposits occur in California , Oregon, Washington, Montana, Wyoming , Pennsylvania, Maryland , New Mexico , North Carolina, Alaska, and the Phillippine Islands , less than 1 percent of the ore used in the United States is obtained from these deposits . Most of the ore in peacetime has been supplied by imports from South Africa, New Caledonia, Turkey, and Cuba . The mineral chromite , the most important chromium ore , is an isometric spinel with an ideal composition of FeO Cr2O3 , but commercial chromite has the variable composition (Fe , Mg) Oʻ (Cr , Al , Fe) 203. Chromite has a black color , a specific gravity of 4.4 , and a hardness of 5.5 . In thin section the color is reddish -brown to black . Chromite occurs in dunite and pyroxenitic ultrabasic rocks , which are composed of iron- magnesium silicate minerals such as olivine , saxonite , serpentine , and enstatite . These are also the gangue minerals . Com mercial ore occurs at random in the country rock in kidney- or lens - shaped deposits , which have no apparent relationship to each other . Stringers , veins , and bands often cut the country rock without regard either to fracture or to other deposits . Some beach sands , such as those in southern Oregon, contain chromite .

Mar 1, 1943

By Franklin H. Persse

Domestic bismuth supply was projected from production figures for the ores in which it occurs--copper, lead, zinc, and tungsten. Published and unpublished data concerning host ores were examined to determine bismuth reserves and resources, and mine production. Potential recoverable bismuth occurring with reserves and resources of copper, lead, and zinc was estimated to be 36.3 million pounds. A bismuth availability diagram was developed from quantity estimates and ratios of production cost to value for these host ores. Additional recoverable bismuth occurring with domestic tungsten reserves was estimated to be 1.5 million pounds. Domestic byproduct production of bismuth will approximate 1.3 million pounds annually by 1980. This quantity will provide about 37 percent of the 3.5-million-pound estimated requirement for that year. Known world supply of bismuth appears to be sufficient for world demand to the end of this century. The study indicates that bismuth reserves and potential resources in the rest of the world have not been adequately reported.

Jan 1, 1970

By J. F. Barkley

The following questions and answers were prepared principally to supply information in answer to general inquiries received by the Bureau from those contemplating the use of propane and butane fuels . Primary or basic information only is covered; this usually gives enough guidance for most inquirers . To those who wish information of the treatise type , the handbook , Butane- Propane Gases , published by the Jenkins Publications , Inc. , 1709 West 8th Street , Los Angeles 14, Calif . , is suggested .

May 1, 1949

By Raymond O. Dannenberg

The gas-combustion retort developed by the Federal Bureau of Mines at the Rifle Oil Shale Project near Rifle, Colo., is a continuous, gravity-feed retort. The heat required to convert the kerogen in the oil shale to liquid oil is generated by the combustion of product gas and carbonaceous residue remaining on the retorted shale after the kerogen has been converted to oil, gas, and residue. A study of the effects of the process variables on retort operation, product yields, and product properties is important to the successful solution of the problems encountered in the development of a satisfactory process. Statistical methods were used to design the experiments and analyze the effects of the rate of shale throughput, the composition of dilution gas, the height of the shale bed above the air entry, air-gas distributor design, shale size range, and the ratios of the flow rates of the various gas streams entering the retort to the rate of shale throughput.

Jan 1, 1960

By J. G. Walters

Analyses of light oils produced from the fluidized carbonization of coal at 485°, 550°, 600°, and 660° C are presented. Tar vapors from 485 C fluidized carbonization were thermally treated at 600°, 700°, and .800° C, and the analyses of light oils produced by this treatment are also presented. Procedures were developed for analysis of coal carbonization light oil by gas chromatography to permit a more definitive analysis than can be obtained by the conventional distillation procedure. An increase in low-boiling olefins, benzene, and toluene, a decrease in low-boiling paraffins, and little change in the remainder of the aromatics was observed with increased temperature of carbonization.

Jan 1, 1965

By Robert E. Wood

The compressibility factors, Z, of helium, nitrogen, and helium-nitrogen mixtures in the three-dimensional space of temperature, pressure, and gas composition have been related to the Leiden form of the virial equation of state. The dependency of virial coefficients through the fifth on temperature and gas composition has been established for the temperature range 133.15° to 748.15° K. Compressibility factors, Z, have been computed from the equation of state and tabulated as functions of gas composition, pressure, and temperature. Tabular values of Z are presented for 30.00 through 100.00 percent helium for temperatures from 240° through 700° R for pressures from 14.696 through 3,050 psia and for temperatures from 720° through 1,300° R for pressures from 14.696 through 1,500 psia. Tabular values of Z are presented at increments of 5.00 percent helium and 20° R, and, for pressures greater than 50 psia, at increments of 50 psi.

Jan 1, 1967

By M. Howard Berliner

In August 1943 the Bureau of Mines completed seven churn-drill holes in an area of old mine workings near Linden, Wis., formerly known as the Argall mine. The work was undertaken as part of a general investigation by the Bureau of the zinc and lead producing area of southwestern Wisconsin at a time when special effort was being made to increase the production of metals necessary for war. The area was selected for investigation on the basis of its favorable geologic structure, past history, and apparent mineralization.

Jan 1, 1948