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By K. R. Van Doren

The polynomial method for estimating virial coefficients from experimental data suffers from three serious defects: (1) There is no known relationship between the polynomial coefficients and the virial coefficients, (2) the values of the estimates depend upon the degree of the polynomial and the particular set of values used for the independent variable, as well as the random errors in the dependent variable, and (3) the variances calculated for the estimates do not represent the mean square errors of estimation. Attempts to overcome these defects have thus far been unsuccessful; these attempts have also failed to account for the fact that none of the virial coefficients are uniquely determined by the values of the dependent variable for a finite set of values of the independent variable. The conclusion is that virial coefficients cannot be reliably estimated from experimental data unless additional information about the virial expansion itself, such as its rate of convergence, is available.

Jan 1, 1969

This report is the 21st in a series summarizing research and technologic work on coal and related investigations by the Federal Bureau of Mines - the Chard of the series published on a calendar-year basis 2/ Subject publica¬tions of the Bureau during 1956 are cited, and pertinent Bureau work is described briefly. The most effective method of conserving our important coal reserves is through improved technology of production and utilization. Associated problems form the program of the Bureau.3 4 5 6/ Potential production is depend¬ent on a knowledge of the quantity and quality of the reserves, and the Bureau continues to contribute information on this subject. Many problems are being studied that relate to improvements in current production, including mining methods and health and safety measures. Preparation of mined coal is necessary for its most efficient utilization. Preparation by conventional methods is being studied, as well as the development or new methods. Fundamental studies on the structure and properties of coal are necessary to insure full advantage of the special qualities of different coals. Controlling factors in the efficient use of coal in combustion, carbonization, gasification, and direct and indirect hydrogenation of coal are being studied continuously, and new processes are being investigated. The many advances in all these fields are discussed.

Jan 1, 1959

By H. W. St. Clair

Sampling of heterogeneous mixtures of fused metals or solidified melts is subject to errors not met in sampling finely ground ores or granular materials. These errors arise largely because of the segregation of constituent metals that usually takes place during solidification. It is seldom that a random sample of a lot of metal will represent the composition of the entire lot. The problem becomes especially difficult when it is necessary to make accurate analyses for a segregated impurity present in very small amounts. This paper discusses some of the pertinent experimental observations made in selecting a method for sampling melts of aluminum and zinc containing small amounts of iron and silicon as impurities. Although this experimental study dealt only with sampling this specific combination of metals, many aspects of the study apply generally to any mixture of mol ten metals containing minor constituents that segregate rapidly during freezing of the melt.

Jan 1, 1949

By B. H. Caudle, A. D. PUCKETT

This paper summarizes precent knowledge of the ignition qualities of pure hydrocarbons likely to be present in modern Diesel engine fuels, as shown by an extensive search of the technical literature. The report also discusses the possible significance of cetane number and hydrocarbon struc- ture. Cetane or cetene numbers, and other physical properties, are tabu- lated for about 100 hydrocarbons, and a bibliography is appended. In recent years the Diesel engine has enjoyed increasing popularity due to its dependability, inherent characteristics of fuel economy, and the fact that it operates on a fuel that hitherto has been available in comparatively large quantities at a low price. These qualities have en- abled the compression-ignition engine to compete very favorably with other types of prime movers in many fields and have led to predictions of fur- ther rapid expansion in the application of Diesel power. In a survey of the field of all petroleum fuels for combustion engines, Holaday et al (9) have predicted that by 1948 railroads will be using 10 times as much Diesel fuel as was used in 1939 and that over-all consumption will have doubled that of 1939. Other estimates of the yearly demand for Diesel fuels five years hence vary from 2,6 to 5 times the amount used in 1944. Into this picture has come the question of whether the greatly in- creased production to meet this estimated demand is compatible with the maintenance and possible improvement in quality of fuels necessary to satisfy future engines. Unfortunately perhaps for the Diesel engine, factors other than those of simple arithmetical multiplication must be considered. For example, the consumption of oil in central heating plants doubled from 1935 to 1943, and a further increase of 57 percent of the 1943 demand is expected by 1950. Jet propulsion has been developed to the stage where it is entirely practical for military aircraft. Catalytic cracking plants, many of which were constructed to meet the war- time accelerated demand for high-octane gasoline, are taking their place in the refining industry. All these developments, as well as the Diesel engine, require material of approximately the same boiling range. Virgin gas oils make excellent burner fuels, perform most satisfactorily in the gas-turbine units for aircraft according to present information, and are at a premium as catalytic cracking stock.

Jul 1, 1948

By George A. Morgan

The production and processing of crude petroleum and natural gas are the dominant economic sectors of the Middle East. The IS countries that constitute the region accounted for 26% of world crude petroleum output, 17% of world natural gas plant liquid production, and almost S% of world dry natural gas production. About 66% of total world crude petroleum reserves and 31 % of total world natural gas reserves are in the Middle East. Transportation and port facilities in the region are geared to expediting efficient and rapid shipment of these materials. U.S.-dollar-denominated export sales of these fuels, estimated at $120 billion in 1989, provide funding for further diversification of the mineral industry. This is usually through development of downstream facilities for producing energy intensive metals such as aluminum and byproducts of the fuels such as petro-chemicals and fertilizers. Earnings from the industry are also channeled by sever-al Governments in the region to mineral industry projects in Africa and elsewhere. A fairly wide range of nonfuel minerals is produced in the region. However, the variety of minerals produced, output levels, and the size of the overall nonfuel mineral economy is dominated by Iran and Turkey. Turkey, with a diverse mineral production and strategically situated between Europe and the Middle East, ranked among the top three world producers of boron, chromite, pumice, and strontium. It was also a significant world producer of magnesium com-pounds, mercury, and sodium sulfate. Iran had generally lower output owing to 9 years of neglect to the mining sector between 1979 and 1988. It was a significant producer of gypsum and fifth in world production of strontium. Despite a very small domestic mineral industry, Israel was second in world production of bro-mine and a significant producer of phosphate rock and potash. Jordan ranked fifth in world production of phosphate rock. Iraq ranked about eighth in world production of sulfur, a commodity of major importance in the metallurgical, petrochemical, and fertilizer industries.

Jan 1, 1992

By Horace C. Porter, F. K. OVITZ

The various fuel investigations that were being carried on by the technologic branch of the United States Geological Survey were transferred by law on July 1, 1910, to a new federal bureau, the Bureau of Mines, that was authorized to continue the investigations and make public reports of the results. In consequence of this transfer, the following report is published as a bulletin of the new bureau. The United States Geological Survey had been engaged in analyzing and testing coals, lignites, and other mineral fuel substances under authority given by act of Congress. This work, now centered at the experiment station at Pittsburg, Pa., had its beginning in the operations of the coal-testing plant erected at the Louisiana Purchase Exposition in St. Louis, Mo., in 1904. The results obtained at that plant showed that the work of determining the fuel value of the coals and lignites in the United States with a view to increasing efficiency in their utilization would be incomplete if it did not include systematic physical and chemical researches into the processes of combustion. Hence in its later investigations the Survey carried on such re- searches, concentrating attention on those lines of inquiry which promised results of greatest economic importance. This bulletin is a report on an investigation of the volatile matter in several typical coals-its composition and amount at different tem- peratures of volatilization. As the investigation is still in progress and will doubtless include other coals than those already examined, the bulletin may be considered a preliminary report, stating the prob- lems studied, the methods used, and the results thus far obtained.

Jan 1, 1910

By J. P. Capp

The Bureau of Mines conducted field-scale experiments in underground gasification of coal with oxygen-enriched air. A path about 140 feet long was linked at the rate of LO feet per day through a coalbed hydraulically fractured with a mixture of starch gel and sand. During the best gasification period, which extended for 2-1/2 days, 785,000 std. c.f. per day of 124-B.t.u. gas was produced. In other periods the heating value at times was almost 300 B.t.u. per std, c.f,, but sustained production of such gas was not achieved. During gasification, a total of 50 tons of coal was gasified and 114 tons of coal was carbonized. Approximately 12 million B, t .u. per foot of nominal path was recovered at the surface.

Jan 1, 1962

By S. H. Ash

THE MAGNITUDE of the anthracite industry's drainage problem in the Northern field of Pennsylvania is realized when it is known that, for the 8-year period 1944-51, all pumping plants in this region pumped an average volume of 112.5 billion gallons of water from the mines to the surface each year. This is over 214,000 gallons per minute pumped against an average hydrostatic head of 400 feet each year for that period (12).4 By comparison, Lake Wallenpaupack, the largest artificial body of water lying wholly in Pennsylvania, contains 71 billion gallons of water in its 24-square-mile area; the average volume of water pumped from the mines in the Northern field each year during the 8-year period was 58 percent more than the volume impounded in Lake Wallenpaupack. The natural configuration of the drainage area overlying the Northern field subdivides the total area into two major drainage areas-the Lackawanna River drainage area and the Susquehanna River drainage area overlying the Wyoming Basin. Although the 169-square-mile drainage area overlying the Wyoming Basin is slightly less than half that of the Lackawanna River drainage area (10), the total volume of water pumped to the surface from mines in the Wyoming Basin is 21 percent more than the total volume pumped to the surface from mines in the Lackawanna Basin. From this, it is apparent that the Susquehanna River and the pervious deposits in the buried valley over which it flows in its course across the coal measures of Wyoming Valley is the greatest single source of mine water affecting mines in this area. Because of its relatively flat terrain, the wide flood plain of Wyoming Valley does not facilitate rapid runoff; consequently, much of the surface water seeps directly into the buried-valley deposits and eventually into the mine workings.

Jan 1, 1953

By Jürgen F. Brune, Liming Yuan, Alex C. Smith

To provide insights and assistances for the optimization of ventilation systems for U. S. under-ground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study is being conducted to investigate the effect of the ventilation scheme on the prevention of spontaneous combustion in longwall gob areas. This report focuses on the flow patterns within the gob under three different ventilation systems; one-entry and two-entry bleederless systems as well as a three-entry bleeder system. The gas flow in the caved gob area is simulated as a laminar flow through porous media while the gas flow in ventilation airways is simulated as a fully developed turbulent flow. The air flow patterns are visualized using flow path lines. Air velocity contours and vector data are also obtained. The possible location of critical velocity zones where the gob is most liable to spontaneous heating is discussed.

By W. C. McBee

Technology for the preparation of densifiable sulfur concrete (sulfapave) materials has been devised by the Bureau of Mines. The materials are intended as new construction materials for use in corrosive areas where conventional materials fail. A series of modified sulfur cements were developed, which can be used in combination with dense-graded aggregates to prepare sulfapave materials with excellent corrosion-resistant properties. The materials can be mixed, laid, and compacted into place with conventional hot-mix asphalt pavi.ng equipment. Mixture designs utilizing 5-to 30-pct-modified sulfur cements and dense-graded aggregates gave material properties ranging from rigid to flexible. Laboratory corrosion tests in sulfuric acid showed no material loss or deterioration of physical properties over a 1-year test period in concentrations ranging from 0 to 60 pct at ambient temperatures. Preliminary results on field testing the materials for durability to weathering, corrosion, and traffic have been excellent, with no evidence of failure in the materials.

Jan 1, 1985

By James Paone

The Bureau of Mines studied the behavior of rocks at the initial state of crater formation that results from the stresses created under a drill bit to determine which mechanical properties of rock are important in rock fragmentation by drilling. Although a definite relation between the drilling strength and relevant mechanical properties has not been established, maximum yield strength of rock is apparently a parameter of drillability of rock. The strengths of rock were considered from the Mohr-Coulomb criterion from which the surface of failure was constructed. The results from previous tri-axial tests on Solenhofen limestone were adopted to verify the criterion of failure. Inelastic behavior of some rock types was observed under a low-velocity impact of a hemispherical bit and under static indentation with a similar bit. Quantitative determinations of strengths of Solenhofen limestone) Indiana limestone, and Tennessee marble were made under static indentation. The maximum yield strength estimated from the average stress over the indented area was used as the crushing strength of rock under a drill bit.

Jan 1, 1966

"Status of the Mineral Industries" provides a written and graphic view of the Nation's mineral position and its mineral industries. The report, issued annually by the Bureau of Mines, U.S. Department of the Interior, describes recent activities in mineral production, consumption, imports, exports, and uses of significant minerals and mineral raw materials. Charts profile trends for the past 28 years in supplies and uses of iron, steel, major nonferrous metals, primary nonmetallic construction raw materials, fertilizers, and plastics. Also included are current and historical financial data on the mineral industries, such as debt-equity ratios, asset-to-liability ratios, and plant and equipment expenditures.

Jan 1, 1979

By A. Aly Selim

This report describes the feasibility of predicting percussive drilling rates by equations derived from statistical regression analysis. The least squares statistical method was used and the analysis was performed both by direct and by stepwise linear regression analysis. The predicted penetration rate is a function of the drill power and the physical properties of the rocks penetrated. The results show promise that the technique may be of value in providing a mathematical model by which percussive drill manufacturers and users can predict the performance of a given drill. Experimental work involved two mining type percussive drills. Penetration data for these drills were determined from nine rocks drilled in the laboratory. Drill work rates (power) were determined in a separate series of experiments. Rock physical properties were measured from diamond-drill core samples taken from the same blocks used for percussive drilling.

Jan 1, 1970

By James A. Wasson

Because of the danger to life and property in a coal mine if an oil or natural gas well should be accidentally intersected during mining operations, certain precautionary measures should be carried out prior to entering previously unmined areas. The locations of all wells both at the surface and at the depth of the coalbed should be accurately determined. The condition of the well should be learned from surface observations, and more importantly, from subsurface examination by geophysical logging devices where possible. It is also desirable to learn the physical properties of the hydrocarbon-bearing rock formation and the hydrocarbon fluids. The major hazard presented by oil or natural gas wells to mining operations is that of explosion and fire due to the rapid release of gas into the mine atmosphere. Wellbore pressure, the principal index of danger, should be determined by one or more of the methods described and by a service company such as those listed in the appendix. Because of high pressures involved and the consequent hazard, much emphasis has been placed on underground storage of natural gas in areas containing minable coalbeds. Maps are shown of the principal coal producing areas and the locations of currently active gas storage reservoirs. A checklist has been included of factors to be considered when mining coal in an area where oil or gas wells exist.

Jan 1, 1973

By D. Harrington

Notwithstanding all the effort maa.e to introduce wet drills to prevent dustiness of air of metal-mine workint;s pl2.ces, there has during the pa.st few years arisen in Australia and South Africa an impression that wet drills, in­cluding the Leyner typa, actuali"y cause und..ue quantities of finely divided ore and rock to rise into the air, these fine particles being chiefly attached to · P=i-rticles of fog or spray escc:.ping frow holes using water drills. This fs saia. to have created consternation in the ranks of the min operators who have com­piiei With drastic wet dri llin rf,ubtions, 2nc:i. purchased and operateC1. various types of wet drills at no inconsiderable expeniiture in both money and effort.

Mar 1, 1922

This report describes the activities and publications of the Bureau of Mines Health and Safety Research and Testing Center, Pittsburgh, Pa., for the fiscal years 1960-65. It includes a discussion or work being conducted on roof control, dust explosions, ventilation, health, coal mine fire control, and electrical-mechanical testing, and an abstract of each paper published during the report period.

Jan 1, 1966

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1962, to June 30, 1963, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1963; in general, the research reported in these publications antedates the report period.

Jan 1, 1965

By C. J. Wilhelm

The Carthage field, in Pamela County, Tex., is one of the largest gas-condensate in respect to both areal extent and volume of recoverable gas in the United States. The field (shown in fig. 1) is approximately 25 miles long by 20 miles wide on a southwest to northeast axis and includes 306 producing wells as of July 1, 1948. 3 distinct reservoirs in the Rodessa and Sligo formations have been found in the Carthage area the two main producing zones being the Upper and Lower Pettit, less important production being found in the Hill zone. Although a small amount of commercial production has been obtained in the Travis Peak formation, it has not been included in this report. An engineering study has been made by Bureau of Mines engineers, with the ultimate objective of arriving at an estimate of the gas reserves, by application of the data made available by the operators in the Carthage field. During World War II the Bureau of Mines submitted a restricted petroleum-engineering report on the Carthage field to the Petroleum Administration for War, at which time (March 1944) the development consisted of only 19 producing wells, 7 of which were dual completions. Because of the restricted nature of the first report and the limited development at the time of writing, a more complete investigation and subsequent publication was considered advisable. Bureau of Mines engineers have made use of all available records such as electric logs, drilling-time logs, core descriptions and results of core analyses, well-completion records, and production data in developing this report.

Jan 1, 1950

By D. Harrington

Coal mines and mining-, as well as metal and nonmetallic mines and min¬ing, are not inherently unsafe, although mining people think they are and would like to have everyone else think so. It is now being demonstrated that mines can be operated with essentially as much safety as any other major industrial enterprise; but most mining people, including workers as well as officials, have been slow to realize or admit this. In the past, and with most people even at present, the idea has prevailed that it is utterly impossible to operate a mine without accidents. Although, as in all other kinds of industrial activity, it is true that some injury is likely on occasion to occur to some workers and an extraordinary accident may occur to one or more persons under exceptional conditions, mines can be operated with few if any accidents if a reasonable amount of the right kind of precautionary effort is exerted and kept in effect.

Jan 1, 1934

By Juh W. Chen

A process for recovery of energy from waste coal fines was investigated. The process, which was developed through laboratory, bench, and pilot plant scale experiments, consists of mechanical cleaning followed by high temperature oil agglomeration and pelletization. The process can produce a quality product under an economically and environmentally acceptable condition. Waste coal fines with ash less than 35: and HHV greater than 6,000 BTU/1b have been upgraded to a product with less than 15% ash and HHV Greater than 11,500 BTU/lb. A computer model has been developed to optimize the processing costs and to perform economic evaluation of specific sites. Ultimately tine model can be utilized to establish a priority listing for a region in assisting the determination of reclamation strategy.

Jan 1, 1983