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By Jon C. Volkwein

Dust concentrations inside and outside enclosed cabs on several types of mining machinery were measured by the Bureau of Mines. Results indicated that properly enclosed cabs can offer significant dust protection for machine operators. Recommendations for improvements in cab technologies were discussed.

Jan 1, 1979

By Thomas V. Falkie, R. Venkataramani

The method of analysis was to test a large model containing potentially significant variables and on the basis of the results obtained, to reduce the model to one containing only the essential significant variables. This stepwise procedure of "scanning" a large proposed model and subsequently condensing the model consisted of two cycles of the same series of computational procedures. Data Preparation A majority of the variables measured were continuous over a specific range of values; for example, the variable "Width Ratio" varied in practice from 0.25 to 1.00. However, "dummy" values were assigned to certain operational variables in order that these varia¬bles would have numerical expression. The following variables were described in this manner. Variable "Dummy" Value x3: Development/Pillaring 0, if pillar extraction was being done 1, if development mining was being done x4: Boxcut/Open Cut 0, if a box cut was being made 1, if an open cut was being made The variables under consideration are represented symbolically as follows: Y: Loading rate (tons per minuts): TONS/MIN x1: Ratio, width of cut/width of cutter: WDRATIO x2: Ratio, height of cut/diameter of cutter: HTRATIO x3: Development or pillaring: D/P

Jan 1, 1972

By Greenwald, H. P

The Bureau of Mines has been conducting experiments on the explosibility of coal-dust in the experimental mine for more than 17 years. The results have been published from time to time3, and a forthcoming technical paper4 will summarize the results and discuss them in some detail. The present paper will be limited to a statement of the more important facts that these researches have discovered.

Apr 1, 1929

By P. W. Jeran

The Beckley mine is one of five new mines in a heretofore unmined portion of the Beckley coalbed. The remoteness of these new mines from prior mining and their greater overburden preclude applying methane emission experience obtained in the old mines. Four sections of the Beckley mine were monitored. The data gathered show that variations in methane emission cannot be explained by variations in coal production. Although overburdens varied by as much as 30 pct, no correlation with methane emissions could be determined. The rib emissions increase with increased length of rib from a section advancing into virgin coal and do not decline over a prolonged idle period (32 days) whereas some decline has been measured for a section not mining into virgin coal. The indication is that degasification prior to mining will reduce the hazard of methane emissions in this area of the Beckley coalbed.

Jan 1, 1977

By Raymond B. Ladoo

The uses of talc are many but are not, in general well known or fully developed within the last decade several companies have realized the possibilities of greatly increased use and have intelligently proceeded to develop some of the fields which seemed most promising. This has had a tendency to lift talc from the obscurity in which it had existed for years, but the work is only started and much remains to be done. Considerably more attention has been paid to the technology and utilization of talc in Germany and Austria than in this country, despite the fact that the United States produces 65 of the world's talc and Germany and Austria combined but 5.4%. In the "Bericht,uber die tatigkeit des verbends der talcum-interessenten in Oesterreich-Ungarn" (Proceedings of the Austro-Hungarian Talc Association), for the years 1912 and 1913, many notes upon new uses appeared, together with suggestions as to further development of old uses. Aside from a few notes on the use of tar in paper, little has been published in the English language upon this subject. By recent action of the Talc and Soapstone Producers Association (U.S.A.) funds for research into the properties and uses of talc have been made Available and it is hoped that markets will be materially broadened a a result of this work.

May 1, 1920

By H. H. Dewing

The Bureau of Mines conducted a laboratory-scale investigation of a technique that produces zinc sulfate and elemental sulfur from sphalerite concentrates by reaction with sulfuric acid at 175° to 200° C and ambient pressure. The objective of the investigation was to develop a hydrometallurgical method of producing zinc from sulfide concentrates that does not generate sulfur dioxide pollutants. Reaction with 80-to 85-pct sulfuric acid produced 4 moles of sulfur for every 3 moles of sphalerite reacted, with minimal production of sulfur gases under optimum conditions. More than 98 pct of the zinc was recovered as zinc sulfate after 3 hours at 175° C. The reaction mixture was leached with simulated spent zinc electrolyte containing 13-pct sulfuric acid to recover zinc sulfate from the insoluble, high-sulfur residue. Neutral zinc sulfate, which is required for electrolysis, was separated from the sulfuric acid solution by crystallization as ZnS04?7H20 at -10° C. Up to 80 pct of the water in the recycled electrolysis solution was removed by the crystallization process; evaporation was used to further concentrate the sulfuric acid for reuse in leaching sphalerite. Advantages of the proposed method over conven-tional roasting and leaching include virtual elimination of sulfur dioxide, production of a solid sulfur byproduct, and higher zinc recoveries due to elimination of zinc ferrite losses.

Jan 1, 1978

By Robert P. Vinson, Fred N. Kissell

This report describes three coal mine ventilation studies by the Bureau of Mines in which sulfur hexafluoride (SFG) was used as a tracer gas. One of these studies was conducted to determine air movement and leakage in a sealed area. Another was run to determine the ventilation efficiency of a bleeder system. Finally, a study was made of air leakage across permanent stoppings of parallel intake airways. These studies proved sulfur hexafluoride to be a useful addition to the equipment commonly used in coal mine ventilation analysis.

Jan 1, 1976

By G. Nuñez, M. A. Pathak, C. F. Stanley

"Holographic interferometry is a non-destructive technique to detect small deformations1 of an object. It is a whole-field technique· with an accuracy of a few microns. An adaptation of holographic interferometry is time-averaged holographic interferometry which is particularly useful in detecting small vibration amplitudes of an object under investigation. Its application to biological tissue is especially difficult due to the combination of (a) the high sensitivity of the technique, and (b) the tendency of these objects to deform excessively, or move during the testing period. (This is also compounded by the changing moisture content of the tissue surface.)Ideally, a pulsed laser and fast-acting thermoplastic film camera could be chosen to overcome these difficulties, but the total equipment cost could exceed $75,000. In this paper we describe our relatively economical method to apply time· averaged holographic interferometry to an excised animal lung, utilizing holographic plates and a mechanically-shuttered continuous-wave Argon laser.EXPERIMENTAL METHODThe schematic of the experimental setup is shown in Fig. 1. The holographic equipment, including the laser, is fixed on a 3 ft x 6 ft x 4 in. honeycomb holographic table. This table is functionally similar to one described by Mark and Horsch2 which can be constructed for about one thousand dollars. The holographic table itself rests on six inner tubes to absorb floor vibrations. All unnecessary vibrations must be reduced to preserve the quality of the holograms. A laser beam from a 0.5-watt continuous-wave Argon laser is split by a circular variable beamsplitter (Newport Corporation Model 50GOOAV.1) into two beams, i.e., an object beam and a reference beam. The object beam is again split into two beams of equal intensity by a 50150 beamsplitter (Newport ·Corporation Model BS.1). These beams are optically filtered and expanded by spatial filters (Newport Corporation Model 910) to cover as much area of the object as possible. Soft biological tissues exhibit low reflectives, resulting in a relatively high reference to object beam ratio of roughly 5 : 1 at the holographic plate."

Jan 1, 1989

By Ted C. Briggs

A removable-jacket distortion apparatus was constructed and used to measure distortion coefficients for two high-pressure vessels. The measured distortion coefficients were used to compute distortion coefficients for volumes VI and (V1+V2) of a 1,000-atmosphere Burnett compressibility apparatus for the temperature range 0° to 75° C. Young?s modulus for Armco 17-4 PH stainless steel, heat treated to condition H1150-M, was computed from experimentally determined distortion coefficients. A 10-to 14-percent correction to the values obtained for Young's modulus may be required because pressure vessel end effects were neglected. The distortion coefficients of the compressibility apparatus are believed to be accurate to about 1 percent.

Jan 1, 1970

By A. W. Ambrose

"Records of individual wells form the basis for the successful operation of any company engaged in the production of petroleum. The expense attached to the compilation of records is negligible in comparison with the benefits resulting from their use. There a company has not a complete system of records, immediate attention should be given to the preparation of forms upon which to collect data, and, to the collection of data for these forms. The records needed vary with each district, but for each field a set should be adopted that will best meet the needs of each property. Practically all operators, and particularly all successful operators, agree on the necessity of good records, shopping what the wells have done, are doing, and may be expected to do in the future. Any operator realizes the value of records of sales of oil and should place almost equal emphasis on the records of well logs and histories showing the east and present performances of wells. Indeed, trustworthy records are absolutely necessary for the proper operation of any oil or gas property.Complete records should be kept on each well from the time the location and elevation are determined until the well is abandoned, and the engineer should review old records often enough to be familiar with the past performance of the various wells and with the conditions that affect production. Some of the forms that may be prepared are:--"

Mar 1, 1920

By Charlie Wyche

Principal mineral products in the Dominion of Fiji were gold, silver, pit and quarry construction materials, and cement. In 1981, the combined value of these commodities accounted for about $11.6 million,2 over 85% of the total value of mineral output. Production of cement, sand and gravel, and quarry products increased substantially above the 1980 level. Mining bated on gold production was decreasing, and employment in the industry was declining. The better grade deposits in the one active mine were worked out, and only another 10 years' production at current rates was estimated to remain. While the high world gold price of 1979-80 led to intensive exploration, there has been little sum.

Jan 1, 1983

By J. E. Murphy

Field freezing was used by the Bureau of Mines to effect the redistribution of the components in a cerium-12.5-atomic-percent-iron alloy. The application of the electric field caused the iron to migrate toward the anode. A field intensity of 0.04 v/cm and a current density of 240 amp/cm2 were used. The conditions that yielded the greatest redistribution of alloy components were a small thermal gradient along the specimen (from 5° C/cm to 10° C/cm) and a very slow freezing rate (0.15 cm/hr). Under these conditions it was possible to process specimens of ½ -inch diameter as compared with the capillary-size specimens used by most previous investigators.

Jan 1, 1968

Crosson and Peters treat the errors that result in miner location due to errors in the overburden earth model used for computing location. A parallel effort by J. Powell of PMSRC is discussed here, where the location method used is that of the Westinghouse location program - "Miner". This location program was tested by Powell by using arrival times generated from the overburden earth model of Table l* rounded to the nearest millisecond. Location computations were then made using 3 geophones at a time. The average location is tabulated for all geophone triplets except when 3 geophones are in line. Geophone arrays were as shown in Tables 2 and 3. The manner in which the test was done is illustrated in Figure 1. I. SUMMARY OF RESULTS The arrival time differences, based on the Table 1 earth model, together with geophone locations based on the array geometries of Tables 2 and 3, were entered into the computer, together with a stated depth of 700 feet and an estimated overburden seismic velocity of 10,000 feet per second. These parameter values were processed by the location program - "Miner". Figure 2 illustrates the interpretation of the plots and data. The tabular data and plots of Table 4 and Figures 3, 4, and 5 illustrate the location error results obtained. These plots indicate that for sources within the array, the errors are considerably less than the measured errors obtained during field tests of the present location system. The possible reasons for this discrepancy are noted in Part Eight (Earth Models).

Jan 1, 1974

By Murray Weintraub

The Bureau of Mines investigated the aerodynamic factors that control the functioning of the blowcase devices used in pneumatic processes for dispersing solids. Alumina powder of 8-micron mass-mean diameter was placed in 0.75- inch-diameter by 10-inch-long cylinders} and a blowcase technique was employed. It was determined that dimensions and gas rates for discharging the powder from the cylinder by a stream of gas may be calculated by assuming a fluidization mechanism and extrapolating residues to a desired finite quantity or to zero at the terminal velocity. The state of agglomeration of a powder at discharge may be determined from measurements of the velocity required for zero residue.

Jan 1, 1967

By Marvin L. Whisman

A radiotracer technique developed by the Bureau of Mines extends to the parts-per-billion range the sensitivity for determining contributors of deposits formed in stored and thermally stressed jet fuels. The method depends upon measuring radioactivity associated with thermally induced deposits from fuels containing one labeled compound. The technique was applied to 88 test blends, representing 12 fuels and nine carbon-l4 labeled fuel constituents or fuel additives, or both. Data from results of these tests are included in this report. With this radiotracer technique, the contribution of fuel components and additives to thermally induced deposits in a variety of fuel environments was estimated before and after storage.

Jan 1, 1969

By Stuart R. Zimmerley, John Gross

"In the study of ball-mill grinding at the Intermountain Experiment Station of the United States Bureau of Mines at Salt Lake City, Utah, it was desirable to measure the work input to a ball mill at the mill itself so that consideration of motor efficiency and transmission losses would be eliminated.The device adopted is essentially that used by Prof. H. E. T. Haultain4 in measuring work input to rolls. The mechanism was changed only so as to adapt it to a ball mill.Figure 1 is a diagrammatic sketch of the apparatus.The pulley which rotates the mill is loose on the mill shaft and is equipped with ball bearings. This pulley is connected by means of three tangential springs to the driving plate, which is solid on the mill shaft. Power applied to the loose pulley is transmitted to the driving plate, and hence to the mill, by the three springs; the greater the resistance of the mill, the greater the spring extension. The extension of the springs is transmitted by the steel extension tape to the differential integrating meter.The integrating meter is operated by two friction wheels in contact with the integrator disk which revolves at a definite ratio of speed to that of the mill. The friction wheels are held in contact with the disk by the spring suspension of the integrator and are connected to a differential gear cage, the revolutions of which are recorded on a counter such as is used in gas meters. Due to the differential gears the c e is stationary when the two friction wheels revolve at the same speed in opposite directions; this condition exists when the integrator is centered on the disk and corresponds to no load or to a zero spring extension. As the lead is applied, the springs extend and move the integrator from the center or zero point, resulting in a difference of speed between the two friction wheels. Due to the revolution of the differential cage this change in. speed is transmitted to the counter. The integrator and extension tape system is kept taut by means of a light spring attached to the integrator, the spring having just enough tension to assure that the integrator returns to zero when the load becomes zero."

Feb 1, 1931

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine if the primary gas toxicities evolved during the early (-300° C) and later (>400° C) combustion stages of mine conveyor belts could be predicted by a smoke particle characteristic. The experiments were conducted in an approximately 20-L furnace at set furnace temperatures of 150°, 250°, and 1,000° C, with a furnace airflow of 10 L/min. The variables studied, as a function of time, included hydrogen chloride and carbon monoxide concentrations, the average smoke particle diameter (d8 and number concentration (no), and the product of the average smoke particle diameter and concentration (dgn0) Other variables included the sample and furnace temperatures and the sample mass weight loss. Results show that the inverse of the smoke particle diameter-concentration product (ldgn0), correlates directly with the hydrogen chloride and carbon monoxide toxicities released in large quantities during the early and later stages of combustion.

Jan 1, 1989

By Oliver Bowels

Many inquiries are received by the United States Bureau of Mines for the names of elementary books on geology, mineralogy, methods of identifying minerals, prospecting, and similar subjects. In response to this demand the following brief bibliography has been prepared. As many of the inquiries are received from those who have limited technical knowledge of the subjects involved, the bibliography includes the simpler texts which present the subjects in nontechnical language. Other texts contain glossaries which define the technical terms used. A short note following the title indicates the character of each book, the number of pages, and the price. Thus, elementary mineralogists or geologists, prospectors, mineral collectors, nature students, or travellers may select the texts that best suit their requirements and their capabilities. To supply the needs of more advanced students, quite a number of the standard texts used in schools and colleges are included in a second group. A short list of books on economic geology and mineralogy has also been added.

Jan 1, 1929

Several federal and state agencies have promulgated regulations that require the installation of operator protective structures on mobile equipment used in mining, construction, agriculture and logging industries. These regulations cover many different types of vehicles, from small farm tractors to large rubber-tired front-end loaders, and require structures that help protect the operator from death or injury from vehicle overturns, from falling tree tops and logs, from falling rocks, and from tree limbs in clearing operations. Two general types of vehicle operator protective structures have evolved over the past twenty years. The first of these is the "Roll-Over Protective Structure'' or "ROPS" that is essentially a "roll bar" or "roll cage" that provides a relatively safe area for the vehicle operator if the vehicle should tip over and roll. The second protective structure is the "Falling Object Protective Structure" or "FOPS" that provides overhead protection against falling material. The terms "ROPS" and "FOPS" are often used interchangeably (sometimes inaccurately) with "cabs", “canopies” , "roll bars" , protective structures" and other such descriptive names. In this report, "ROPS" describes the function of the structure; "FOPS" also describes a particular function. Thus a ROPS/FOPS could describe a cab or a canopy that provides both roll-over protection and falling object protection. “MESA” is used as an abbreviation for the Mining Enforcement and Safety Administration; "USBM" is used to abbreviate the U, S. Bureau of Mines.

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Jan 1, 2012