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By A. J. Kraemer

The Bureau of Mines for a number of years has been carrying on an investigation of properties of crude oils from producing fields in the United States and has published a series of reports on different fields, including oil fields of Texas3. Production Data The Spindletop field was discovered in 1901 when the pay sand was found at deaths of about 800 feet. During the following twenty-five years a number of attempts were made to find a deep productive sand. All attempts sere failures until a roll drilled by the Yount Lee Oil Company found oil late in 1925. An intensive drilling campaign began at once, and the production of the Spindletop field increased to a daily average of 93,217 barrels in September, 1926; the present production is estimated at 66,000 barrels doily. Tile following table taken from the Oil and Gas Journal for February 10, 1927, shows the daily average and the total production by ninths for 1926.

Jan 1, 1927

By A. W. Khair, M. Ahmad, L. D. Gehl

"This paper presents an analysis of the dynamics of bit wear on the productivity of the continuous miners. Two field surveys have been carried out. The first survey was to assess the impact of bit wear on productivity and production cost. The second survey was to study the wear characteristics of the cutting tool (i.e. magnitude, forms, and mechanisms of bit wear). Primary factors affecting bit wear is identified and laboratory experiments were carried out to study the effects of some of these primary factors on wear in detail. Results indicate that bit wear has a significant effect on the productivity of the continuous miners. Furthermore under the severe geologic conditions (i.e. cutting rock partings and roof and floor rocks) bit wear not only hampers the productivity, but also increases the production cost due to a higher number of bit consumption. This study also indicated that bit wear accelerates beyond 20% of the conical height loss which corresponds to 7% of the weight loss. This increase rate of wear is an indicative of higher abrasion between bit body and cutting material, resulting in a more dusty environment.IntroductionThe high demand for coal production has increased the need for mechanized coal cutting in underground coal mines. Continuous miners have been used in the United States of America for nearly four decades and now presently more than 2000 are in operation. Almost half of the underground coal production of the country is by continuous miners. Today, competition in the coal industry has increased, due mainly to market conditions and legal restrictions, thus placing an emphasis on production, efficiency, and safety. The use of continuous miners has resulted in the generation of respirable coal dust which causes black lung in mine workers. On the other hand, bit wear presents a serious problem as it affects productivity and economy.Much research in the put has been done on energy requirements and mechanism of energy dissipation for ideal rock fragmentation in the cutting process. Recently, dust hazards in underground coal mines as a result of coal cutting has been a great concern to mining engineers as well as environmentalist of the country. In past, much emphasize has been given to fragmentation mechanics (Khair et al, 1989), dust generation due to regrinding (Khair and Xu, 1991) and dust generation due to bit wear (Khair, Xu. and Ahmad, 1992). These studies concluded that dust concentration increased considerably after a bit weight loss of 7% and thereafter the bit should be replaced. Thus, legal restriction by the Mine Health and Safety Administration for the respirable dust concentration in underground might be a factor deciding the level or rate of production using continuous miners. While efforts in research are on reducing dust generation, it is also important and relevant to study bit wear in more detail.Bit wear is affected by three major groups of parameters: (1) machine operating parameters, (2) insitu conditions and (3) properties of rock. Again, past studies have shown that depth of cut, material of tool, position of water jet and velocity of the rotating drum are very important machine operating parameters. The content of the rock/coal material is important as bit wear is usually due to abrasion or adhesion. Diffusive wear becomes dominant only when the temperature exceeds the sensitive range i.e critical temperature. Mechanical tools have indicated that a rise in temperature is a function of drum velocity, properties of cutting material (rock or coal) and properties of tool. Bit wear due to chemical reaction and oxidation art almost negligible in coal cutting."

Nov 1, 1995

By A. J. Kraemer

"During the past several years a great deal of discussion has centered around the question of the permissible limit of sulphur content in fuels for automotive and aviation motors. Under certain conditions of operation, sulphur in motor fuels causes the formation of corrosive substances which attack bearings, wrist pins, and other parts of engines. On the other hand, in making gasoline from certain stocks, the gasoline fraction normally contains a relatively large proportion of sulphur compounds. By the generally used processes of reducing the sulphur content, a significant part of the gasoline fraction is lost as motor fuel, and added expenses are entailed for chemicals, labor, and other process costs. This condition has been an economic burden to some refiners of high-sulphur crudes. In some instances the treating losses have been rather severe and the treating costs relatively high, but the data presented in this paper indicate that the reduction of sulphur content of motor fuel is a problem to a relatively small number of refiners and of little or no concern to the remainder; in fact, more than 90 per cent of the 153 samples analyzed passed the Federal specification requirement, Which limits the sulphur content to 0.10 per cent. 3This report is based upon the results of an examination for sulphur content, Doctor test, copper strip corrosion, and color of the samples collected during January, 1930, for the twenty-first semiannual gasoline survey of the Bureau of Mines. The results of the gravity ad distillation tests of the survey were published as Report of Investigations 2995. The numbering of the samples given in this report is the same as in Report of Investigations 2995; for example, No. 25 of this report is the same sample as No. 25 of Report of Investigations 2995."

Jun 1, 1930

Rock mass classification is widely used throughout the underground mining industry—in both coal and hard-rock mines. The technique has been successful because it— • Uses simple measurements to rate rock mass strength. • Helps mine planners to make the best use of geologic information in mine design. • Makes it possible to compare ground control experiences between mines, even when the geologic conditions are very different.

Jul 1, 2007

By Jr. Watts, B. K. Cantrell, D. H. Carlson, K. L. Rubow

"Abstract — The use of diesel equipment in underground coal mines is controversial because the National Institute for Occupational Safety and Health (NIOSH ) regards ""wholediesel exhaust"" as ""a potential occupational carcinogen."" Threshold limit values (TLVs ) are recommended for the gaseous pollutants CO, CO2, NO, NO2, SO2 and some hydrocarbons emitted in diesel exhaust. There is, however, no TLV recommended for diesel exhaust aerosols (DEA) nor is there a standard method for sample these aerosols.The University of Minnesota and the USBM have collaborated to develop a personal diesel exhaust aerosol sampler (PDEAS) that utilizes size selective, partial impaction and gravimetric analysis. During the field tests of this sampler, numerous air quality measurements were conducted in underground coal mines that used diesel equipment. The objective of this report is to present these data and to assess the impact of diesel face haulage equipment on mine a quality.Air quality data were collected in four underground coal mines. The mines used continuous miners and diesel haulage equipment. Daily samples were collected at the section intake, haulage way and on haulage vehicles. Both full- and partial-shift samples were collected using a variety of aerosol instruments. These included the PDEAS and the micro-orifice uniform deposit impactor (MOUDI) that sample the mine aerosol diesel exhaust fraction. Two of the mines were also monitored for the major gaseous constituents found in diesel exhaust CO,CO2, NO, NC, and SO2. These measurements were made by either collecting bag samples for subsequent gas analysis or by Palmes dosimeters.Concentrations of CO, CO2, NO, NO2 and SO2 were well below regulated levels. The mine average DEA concentration determined by the PDEAS in the haulageway for the three mines surveyed was 0.79 mg/m4, with a standard deviation of 0.19 mg/m3 DEA contributed 65% of the respirable aerosol, at this location. These results were the same as the mean DEA concentrations calculated from size distribution measurements obtained using the MOUDI. This was 0.78 mg/m3, with a standard deviation of 022 mg/m3."

Mar 1, 1992

By Joseph J. Wallace

1. From the standpoint of known recoverable reserves, the following is the order of importance of the beds: Upper Kittaoning, Lower Kittanning, Upper Freeport, Lower Freeport, Middle Kittaning, Clarion, Pittsburgh, and Redstone. 2. mown measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and on 1,800 tons per acre-foot of coal in place, me estimated at 1,859 million short tons as of January 1, 1952. Of this, 1,351 million short tons me in beds 28 inches and more thick. Areas in each bed were omitted from the estimates because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1953

By Charlie Wyche

The principal minerals produced in the Dominion of Fiji in 1982 were unrefined gold, silver, and tellurium. The combined value of these commodities was about $16 million,2 representing over 85% of the total value of mineral output. Cement, sand and gravel, and quarry products were the other minerals produced in Fiji. Despite the small part played by minerals in Fiji's economy, exploration on land and in the coastal areas was carried out by several international mining companies representing Australian, British, Canadian, West German, and U.S. interests. At the end of 1982, 30 prospecting licenses covering 2,300 square kilometers were issued. Most licenses were for copper, zinc, gold, and silver. Total expenditure on mineral exploration was $3.5 million.

Jan 1, 1984

By G. P. Sturm

This work was undertaken by the Bureau of Mines in cooperation with the Environmental Protection Agency to determine photochemical specific reactivities of emissions from automobiles using leaded-premium-and regular-grade fuels and prototype lead-free fuels of comparable octane quality. Emissions were photoirradiated in a 100-ft3 environmental (smog) chamber constructed of aluminum and Pyrex glass at three sets of initial hydrocarbon (HC) and oxides of nitrogen (NOx) concentrations. Reactivity was measured and expressed in terms of rate-of-NO formation (RNo2) and dosages of oxidant, peroxyacetyl nitrate (PAN), peroiypropionyl nitrate (PPN), and formaldehyde (HCHO). The results indicate that the evaporative emission samples and the evaporative plus exhaust emissions samples from the lead-free fuels have, in general, higher reactivities per gram than those from the leaded fuels. For the samples containing only exhaust emissions, the only trend observed was the lower specific reactivity exhibited by the leaded premium fuel exhaust. These differences in specific reactivity are taken to reflect the differences in hydro-carbon composition of the fuels and their evaporative and exhaust emissions rather than any difference in lead content per se.

Jan 1, 1973

By B. W. Gandrud

In 1927 Coghill5 showed that there is considerable liberation of the iron oxide mineral from gangue when the Alabama red iron ores are ground to a size suitable for classification and tabling, but that there is not sufficient to make possible a high extraction and a high grade of concentrate. Coghill states: High extraction and high grade of concentrate cannot be obtained without grinding to a size comparable with flotation or cyanide practice. If grade of concentrate be sacrificed the grinding need not be so severe.

Jan 1, 1934

By C. O. Hawk

As an exploratory effort to produce useful products from coal by a new path, the Bureau has made a few experiments on the fast heating of finely ground coal particles by irradiation with a flash of high intensity light. The flash was produced by an electrical discharge at high voltage through a xenon-filled tube. The flashes lasted from 2 to 3 milliseconds. The reaction took place in small sample tubes, ½ inch-dimeter by 4 inches long, and with small amounts of coal (total amount charged 0.1 gram, probable effective amount not more than 20 milligrams). Average particle size of the coal, estimated on a numerical basis, was 20 microns. Temperatures reached were evidently quite high, because all products obtained in quantity were characteristic of high temperature pyrolysis. Apparently, conversion of the coal was extensive where isolated particles received the full benefit of a flash. It seems particularly significant that acetylene was present in appreciable amounts--comprising almost 3 percent of the total gaseous product in one case. This is good evidence of a short heating period to very high temperature (well above 1,000° C) followed by rapid quenching. Although the results are interesting, they do not suggest any immediate practical application.

Jan 1, 1963

By T. T. Read

"Employee representation in the management of large mining enterprises was first introduced in organized form, by the Colorado Fuel and Iron Co. in 1915. Within the past few years a number of the larger mining enterprises have introduced similar systems and there is growing interest in the subject. This will be stimulated by the final report of the President's Second Industrial Conference, in which the following statement occurs:""The conference finds that joint organization of management and employees where undertaken with sincerity and good will has a record of success. The general principles governing such organizations are stated at length under the title 'Employee Representation. It is not a field for legislation, because the form which employee representation should take may vary in every plant. The conference, therefore, does not direct this recommendation to legislators but to managers and employees.""If the joint organization of management and employees in the plant or industry fails to reach a collective agreement, or if without such joint organization, disputes arise which are not settled by existing agencies, then the conference proposes a system of settlement close at hand and under Government encouragement, and a minimum of regulation. The entrance of the Government into these problems should be to stimulate further cooperation."""

Mar 1, 1920

By D. W. Scott

Thermodynamics is a powerful tool for investigating rotational isomerism in substituted ethanes and related molecules. Accurate calorimetric data can be interpreted to give information, not only about the energy difference between conformations, but also about the shape of the potential barrier hindering rotation from one conformation to another. However, a deterrent to this use of thermodynamics is the labor required to calculate the contributions to the thermodynamic functions for assumed potential functions. Tables of thermo-dynamic contributions for appropriate potential functions can eliminate that labor and greatly facilitate the thermodynamic study of rotational isomerism. In this research, tables of contributions to the thermodynamic functions were compiled for two potential functions typical of some commonly encountered examples of rotational isomerism. TYPES OF POTENTIAL FUNCTIONS Potential function 1, illustrated in figure 1, A, has two equal minima higher than the third. It has the general shape of the barrier to internal rotation in n-butane, for example. The trans conformation of n-butane has the lowest energy, and the two skew or gauche conformations have equal but higher energy. Potential function2, illustrated in figure 1, B, has two equal minima lower than the third. It has the general shape of the barrier in 2-methylbutane, for example. The two C1 conformations of 2-methylbutane have equal energy much lower than the assumed Cs conformation, which has not been observed spectroscopically.

Jan 1, 1962

By David N. Montgomery

The characteristics of a closed cavity acoustic coupler were measured. Various configurations were investigated to determine their feasibility for use in a portable audio dosimeter calibrator.

Jan 1, 1976

By Laxman S. Sundae

In the vast majority of American coal mines, roof bolt holes are drilled dry, mainly because of mine operator concern with the spent water creating adverse working conditions. Wet drilling, however, can increase drilling rates and the effective lifetime of the drill bits used. This study, carried out as part of an ongoing cooperative research program between the U.S. Bureau of Mines and the University of Missouri-Rolla, shows that the large volumes of water conventionally used in wet drilling are not necessary, and the performance benefits from wet drilling can be achieved with total volume flows on the order of 0.4 L per hole. This conclusion is validated based on the measured respirable dust generated in drilling Berea sandstone. The results are confirmed using a variety of bit shapes, which are also shown to have a significant effect on penetration rate.

Jan 1, 2010

By Clarence O. Babcock

Model pillars of limestone, marble, sandstone, and granite having length to diameter ratios of 3:1, 2:1, 1:1, and 0.5:1 were broken in axial compression to determine whether lateral end constraint affected the breaking strength. Steel rings bonded to the ends of the model pillars with epoxy provided, during the loading cycle, a lateral end constraint of about 17 to 30 percent of the average axial stress. The effect of this constraint was to increase the breaking strength of the rock as compared to cylindrical pillars without constraint. The percentage increase in breaking strength varied with rock type and increased as the length to diameter ratio decreased. The maximum increase in breaking strength was 35 percent for marble pillars having a length to diameter ratio of 0.5:1. A theory was developed which relates the expected constraint to the physical properties of the ring and rock.

Jan 1, 1968

By W. H. Young, R. L. Anderson

"Physical conditions, such as thickness and character of the coal seam, dip or pitch of the seam, depth of cover, character of roof and overlying strata, mine water, etc., affect the productivity in bituminous-coal mining. Thickness of the coal seam being mined is probably the most important single item that determines whether the output per man per day shall be low or high; however, in strip mining the depth of cover or overburden to be moved is of equal importance.Bituminous coal is mined today from seams of exceedingly variable thickness - less than 2 feet to more than 50 feet; however, a large majority of the mines are producing .coal from seams 3 to 6 feet thick. The average thickness of the coal seams mined in the United States has not changed materially in the past 25 years. The average seam thickness for all bituminous-coal mines was 63 inches in 1920 4/ and 65 inches in 19)45. As thick seams have been exhausted in the older fields, other thick seams, have been opened in the newer fields.Productivity increased from 4 net tons per man per day in 1920 to 5.78 in 1945. This 45 percent increase in productivity resulted from increased mechanization. The percentage of underground production represented by coal cut by machines increased from 61 in 1920 to 91 in 1945 Mechanical loading increased from less than 1 percent of underground production in 1920 to 56 percent in 1945, and strip mining increased from less than 2 percent to 19 percent of the total production during the same period."

Dec 1, 1947

By W. G. Hopkins

The development of systems for location of miners who have become entrapped following a mine disaster has been one of the major research goals in the Bureau of Mines. This study details the preliminary development of such a system. Current technologies for locating trapped miners from the surface are either simple direction finders or time difference pulse systems that have accuracy limitations. Developing technologies using full vector field measurements at several receiving points are currently being studied. The necessity of measuring field strength with great accuracy can be a drawback in these systems. A system that operates with continuous wave radio signals, whose phase differences can be measured accurately even in weak signal conditions, greatly improves the location accuracy. A microcomputer would be used in conjunction with the system, to gather and manipulate the data to automatically pinpoint the location of the trapped miner. Comparison of this system with existing technology indicates a favorable accuracy/complexity ratio for the phase difference of arrival technique.

Jan 1, 2011

By J. J. Drost

This Bureau of Mines investigation studied the effect of thermal treatments upon concentratability of a western Mesabi Range nonmagnetic taconite ore and is a sequel to Bureau of Mines RI 7567. Magnetic tube tests were used to develop the data needed to calculate separation efficiency, the primary measure of concentratability. A horizontal tube furnace was employed to heat treat and reduce the hematitic ore samples. The two variables studied were roasting temperature and cooling method. The manner of cooling, either by slow cooling or quenching in water, produced no significant difference in concentratability. Roasting temperatures employed ranged from 500° to 1,000° C, and a temperature of 650° C effected the best concentratability. The temperature of 650° C correlated with the most effective roasting temperature for grindability.

Jan 1, 1973

By Steven R. Davis

Dear Interested Party: Subject: Notice of Intent to Solicit Outside Opinions Regarding Amendments to the Rules Concerning the Leasing of State Owned Lands for the Mining of Metallic Minerals The Department of Natural Resources, Division of Minerals, is seeking outside opinions concerning the leasing of state owned lands far the mining of metallic minerals. Enclosed for your information in a copy of the Notice of Intent to Solicit Outside Opinions Regarding Amendments to the Rules Concerning the Leasing of State Owned Lands for the Mining of Metallic Minerals.

Jan 1, 1994

By T. F. Dumm, L. G. Austin

"INTRODUCTIONGomez and Austin (1,2) have recently described calibration procedures for quantitative chemical analysis of particles by energy dispersive spectroscopy using particles mounted and polished in a resin matrix and scanned by an SEM under computer control. Their software is specifically designed for the analysis of Si, Al, Ca, Na, K, Fe and S in coal particles, and in this case the resin is loaded with iodine (3) to enable the exposed cross-section of an embedded coal particle to be differentiated from the matrix. However, the basic ideas of their procedures could be extended to any system of particles where it is desired to measure inorganic species in particles containing light elements such 0, C, H and N which are not directly detected. In these circumstances it is necessary to perform a quantitative determination of the measured components, so that the equivalent volume of light elements in the excited sample volume can be estimated by difference using ZAF and other corrections applied to the raw count intensities.Part of their procedure involves a new technique (2) for estimating background spectrum intensities; the intensity for a particular energy window is then subtracted from the total measured intensity for that window to enable the concentration of the corresponding element to be calculated. In addition, corrections for overlap of peak spectrums are applied. For example, Figure 1 shows some typical spectrums for known materials for the system they used, demonstrating a wide Gaussian spread about the theoretical peak energy. Since background spectrum and peak overlap corrections require a knowledge of the composition of the material, as does the application of the ZAF corrections, it is necessary to have an iterative solution of the equation sets, starting with estimates of the composition based on initial count rate corrected solely for dead time and detector efficiency."

Jan 1, 1989