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By Jeffrey Johnson, Carl Sunderman, Ted Williams, Stephen Signer, Douglas Bayer

To measure the loading behavior of friction bolts, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) installed strain gauges on the interior of friction bolts and developed a battery-powered miniature data acquisition system (MIDAS) that fits inside the hollow portion of the friction bolt. The advantages of this system are that it is protected from face blasts and eliminates the need for external wiring. Laboratory pull-out tests showed that friction bolts installed in a concrete block with resin were loaded to about 1.8 tons/ft of bolt length; bolts installed without resin were loaded to 1.3 tons/ft. Three strain-gauged friction bolts were installed at Hecla Mining Company’s Gold Hunter Mine, Mullan, ID, in the wall or rib of a mechanized cut-and-fill stope. The object of these tests was to establish an installation procedure for the bolt-and-MIDAS combination and to evaluate performance. The stope was advanced in three 15-ft increments and strains induced in the rock bolts by stress changes in the rock were recorded every 30 minutes. The MIDAS proved to be rugged enough to withstand the shock and vibration from nearby (5 ft) face blasting. Data from MIDAS showed that the friction bolt installed with resin was the most sensitive to each face advance. It showed a steady increase in loading to a maximum value of 1000 microstrain. The friction bolt installed without resin showed stick-slip behavior with loads to a maximum of 400 microstrain before the stope was completed.

By E. D. Calvert

The room temperature tensile properties of commercially pure titanium and seven titanium alloys prepared by skull casting were determined in the as-cast and heat-treated conditions. Data were compared with property data from tensile tests on wrought alloys of the same compositions in the as-worked and heat-treated conditions. The alloys evaluated were Ti-5Al-2.5Sn, Ti-6Al-4V, Ti-6Al-4V-lSi, Ti-6A1-2Sn-4Zr-2Mo, Ti-6A1-6V-4Zr-4Mo, Ti-6A1-6V-2Sn, and Ti-11.5Mo-6Zr-4.5Sn. Test specimens were prepared from both static and centrifugal castings and from plate fabricated by forging and rolling vacuum-melted ingots. The data indicate that the alpha and alpha-beta alloys have strength properties in the as-cast condition that are reasonably close to the strength properties of their wrought counterparts in the as-worked condition. An exception to this was the Ti-6A1-6V-4Zr-4Mo alloy for which insufficient data were available to form any firm conclusions. Fine-grained cast structures of Beta III (Ti-11.5Mo-6Zr-4.5Sn) were shown to be generally stronger in the as-cast condition than the wrought alloy in the as-worked condition except for the yield strength of one structure that was unusually low. Heat treatment of this alloy produced properties that were unpredictable. Indications are, however, that optimization of heat treatment parameters for each cast structure could produce strength properties equal to that of wrought materials.

Jan 1, 1974

By W. S. Sanner

Pyrolysis (destructive distillation) techniques developed at the Bureau of Mines to determine the yield and quality of the products from coal were used to convert municipal (household) and industrial refuse into potentially useful solids, liquids, and gases without adding to environmental pollution. The tests demonstrated that a ton of municipal refuse can be converted into 154 to 424 pounds of solid residue, 0.5 to 6 gallons of tar, 1 to 4 gallons of light oil, 97 to 133 gallons of liquor, 16 to 32 pounds of ammonium sulfate, and 7,380 to 18,058 cubic feet of gas. A ton of industrial refuse, consisting of paper, rags, and cardboard, can be converted to 618 to 838 pounds of residue, 1.5 to 3 gallons of light oil, 68 to 75 gallons of liquor, 12 to 23 pounds of ammonium sulfate, and 9,270 to 14,065 cubic feet of gas. The energy from the gas is more than sufficient to provide the heat for the pyrolysis.

Jan 1, 1970

By Travis Q. Lyday

During 1981, Ecuador's gross domestic product (GDP) increased by a reported 4.8% in real terms, a slight improvement over that of 1980. In current prices, the CDP in 1981 was estimated at $13.7 billion.2 The inflation rate increased to 15.6% according to official figures, above that of 1980. Ecuador's production of petroleum increased 3% in 1981 compared with that of 1980. The consortium of Corporación Estat al Petrolera Ecuatoriana (CEPE), the state oil company, and Texaco, Inc., produced almost 98% of the total from their Putumayo Basin operations in Oriente, the eastern jungle region. In sharp contrast, output from the Santa Elena Peninsula Fields, where oil was first produced commercially in 1921, continued to decline, producing only 510,000 barrels, a decrease of almost 8% compared with that of 1980.

Jan 1, 1983

By Thomas E. Lobb, Harry C. Verakis

Significant progress has been made in the reduction of serious injuries and fatalities resulting from mine blasting operations. Despite the progress, injuries and fatalities continue to occur. A leading cause of injuries and fatalities from blasting continues to be inadequate blast area security. Even though significant improvements in technology have been made, insuring adequate blast area security remains a challenge and requires constant vigilance. The advances in technology have created safer blasting products and have improved productivity and economics by enabling large, more efficient and effective blasts. However, as blasts grow larger in size, the complexity of adequately securing the blast area increases even more. Periodically the basic fundamentals involved in blasting safety should be reviewed, particularly for securing a blast site regardless of the size of the planned blast. Factors such as flyrock and toxic fumes must be taken into account to insure the safety of persons and property from the results of a blast. This paper examines the factors related to injuries due to inadequate blasting shelters and blast area security, and identifies mitigation techniques. The key concepts are: (a) accurate determination of the bounds of the blast area, (b) clearing employees from the blast area, (c) effective access control, (d) use of adequate blasting shelters, (e) efficient communications, and (f) training. Fundamentals are reviewed with an emphasis on analyzing task elements and identifying root causes for selected blasting accidents. Mitigating techniques are presented along with discussions and examples.

By David A. Benjamin

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 24,600-acre Orejana Canyon Wilderness Study Area (OR-001-078), in order to evaluate its identified mineral resources. The study area, located in Harney County, 76 mi northeast of Lakeview, OR, is underlain by Miocene basalt, rhyolite flows, tuffs, and tuffaceous sedimentary rocks. No mines, prospects, or claims were found within the study area. According to the U.S. Bureau of Land Management, the tuffaceous rocks have a moderate favorability for the occurrence of diatomite and a low favorability for zeolite resources. Also, the rhyolite flows have a low favorability for the occurrence of perlite resources. However, U.S. Bureau of Mines' studies indicate that no metallic or nonmetallic resources are present in the study area.

Jan 1, 1987

By R. A. Cattell

A technologic group such as the Petroleum and Natural Gas Division of the Bureau f Mines, which conducts research on many of the complicated and frequently interrelated problems f extracting crude oil and natural gas from the ground, transporting them to market or to daces for subsequent treatment, and manufacturing products, should report progress from time to time. Engineers and others who apply the results obtained by this division are closely associated with its personnel, because many of the problems are attached cooperatively with groups in industry. Some of this cooperation is formal, as exemplified by work now in progress under cooperative agreements with the States of Oklahoma, Kansas, and others, but much of it is informal, prompted by the desire to be mutually helpful in the public interest. Furthermore, the published reports of the Bureau on subjects pertaining to petroleum and natural-gas technology come to the direct attention of a relatively large number of persons, whose interest in results and appreciation of the value of this type of work have caused them to be kept currently informed regarding available data.

Jan 1, 1940

By J. E. Crawshaw

"The few previous observations of the effect of turbulence on limits of inflammability have been made on a small scale in turbulence produced either by a fan or by movement of the mixture.By a suitable amount of turbulence from a fan the lower limit of methane was 5 per cent as compared with 5 per cent observed for quiescent mixtures in the same vessel.3 With a streaming movement of the gas mixture within the range of speed from 35 to 65 centimeters per second (69 to 128 feet a minute) the lower limit was approximately 5 percent,4 For a quiescent mixture of ethane the lower limit was 3.10 per cent ethane, but with fan running at a moderate speed a 3 per cent mixture exploded.5The object of the tests herein reported was (1) to determine the lower limit of natural gas in a mixture of natural gas and air Which would be ignited and propagate violently when the turbulence was produced by explosives fired from a cannon into the mixture; (2) to observe the behavior when the mixture contained less than this low limit; and (3) to determine how turbulence produced by a fan affects thin limit.Four series of tests were run, three of which were to determine the effect of different sources of ignition: Tests with (1) an electric igniter; (2) 3F black blasting powder stemmed with 2 pounds of dry fire clay stemming used to ignite the mixture, and (3) 40 per cent straight nitroglycerin dynamite unstemmed. The fourth was made to study the effect of turbulence produced by a two-speed electric fan, using an electric igniter as the source of ignition.In both series of tests with explosives, charges of 50 and 200 were used to determine the effect of increased quantity of explosives on the lower limit of natural gas."

Jul 1, 1930

By John J. Sammarco

The mining industry has the highest average annual fatality rate among major U.S. industries. To address this, the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory (PRL), is conducting major research programs to reduce the hazard exposure of miners. One of the recently concluded programs at PRL developed the enabling technology for remote-controlled mining. An application involves the manual process of extracting and hauling coal where operators, in the tight confines of a mine, can be struck or caught by mobile machinery. The approach to remedy this problem uses a guidance system on the continuous haulage equipment so that it follows the continuous mining machine that extracts coal. This, in essence, involves sensor-based docking of the machines. Sensors functioning in the hostile mine environment of dust, methane gas, and water play the key role. Computer analysis of the mining machine's movements and empirical machine characterizations established operating requirements and spatial limitations to ensure proper loading of coal into the haulage equipment. These data served in the selection of a guidance sensor. Technologies such as scanning laser systems and ultrasonic sensors have frequently been used in other applications, but were found unacceptable. However, a near-infrared sensor employing active targets met the requirements. The sensor has a nominal 75b conical field of view and a range from 0.1 to 18.0 m. For the single-target mode, nominal range accuracy was 4.3% at a distance of 3.65 m. Correction algorithms were generated, which reduced the error to 0.6%. Airborne dust testing showed less than an additional0.8% accuracy (worst case) degradation at dust levels up to 15 mg/m3. Using four targets, the nominal range accuracy was 0.4% without correction algorithms. Analysis of dynamic testing of a continuous miner and haulage showed that accuracy was maintained and total target loss did not occur. A guidance system for the haulage system to follow the mining machine does not exist commercially. Such a system can reduce fatalities, injuries, and exposure to dust and noise.

Jan 11, 1998

By P. C. McWilliams

Theoreticians in soil mechanics have been pursuing a probabilistic approach to the factor of safety of an embankment or darn for the past 10 years. The motivation for this work is in contrast to the current practice of deterministically computing a factor of safety and treating it as an absolute with no regard to its inherent statistical variability. Basic to the probabilistic approach is the selection of an appropriate statistical model to represent the histogram or probability density function (PDF) of the factor of safety values, Rather than simply assuming which PDF is appropriate, the Bureau of Mines collected data at two waste disposal embankments for consideration, This report addresses three candidate models, using the techniques of nonlinear curve fitting, and identifies the "best" model. A propagation of error formula for estimating the variability of Fellenius? factor of safety is also discussed.

Jan 1, 1983

By M. J. Ferrante

Laboratory-scale tests were undertaken to examine several electrolytes for possible use in separating nickel and cobalt from products being prepared at Nicaro, Cuba. The most extensive work was done with nickel sulfate-ammonium fluoride, ammonium fluoride, ammonium sulfate, and nickel sulfate-boric acid electrolytes. All four electrolytes exhibited some selectivity for dissolving nickel carbonate from Nicaro basic carbonate used for regeneration. The nickel sulfate-ammonium fluoride electrolyte exhibited less selectivity for dissolving nickel carbonate from Nicaro basic carbonate than it did from synthetic mixtures. Ammonium fluoride leaching experiments showed that a low concentration and high temperature gave a good nickel extraction with C. P. reagents; however, this was not confirmed in tests using Nicaro basic carbonate. Electrolytic tests employing ammonium fluoride leach liquors gave no further separation, since approximately 90 percent of the cobalt was deposited at the cathode with the nickel.

Jan 1, 1958

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in the production of crushed stone. These studies, made at quarries scattered over the eastern and southeastern parts of the United States, have not been completed, but to make results available to thee industry as early as possible it was decided to publish summaries of the studies made to January 1, 1939, as a series of progress reports. The first of these reports dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The present circular discusses analyses of the time Studies of the haulage systems at the same quarries. OBJECT OF STUDY The pressure of business problems frequently requires the entire attention of quarry management and in consequence internal plant economies often are neglected, Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that similar studies of many plants by impartial engineers -would disclose possibilities for cost reduction or greater efficiency in internal plant processes.

Jan 1, 1939

By A. J. Kraemer

For a number of years the Bureau of Mines has been conducting an investi-gation of crude petroleum from producing fields in the United States and the Western Hemisphere and has published a series of reports on these fields. Analyses of crude-oil samples from some oil fields of Louisiana are given in Bulletin 291. Analyses Of 26 representative crude oils from various producing formations of southern Louisiana are given in this report. These samples are from 14 fields in 10 parishes in the southern part of the State, usually designated as the "Louisiana Gulf Coast area."

Jan 1, 1934

By J. Koster

During the past several years, alunite from the Marysvale (Utah) region has been the subject of investigation by the Electrometallurgical Section of the Bureau of Mines. The nature and occurrence of this mineral, with considerable data on the Utah deposits, together with a number of results of preliminary experiments, have been given in a previous report.6/ The geology of the Marysvale region has been reviewed recently.7/ The present paper reports the results obtained by a method involving the sintering of alunite with boric acid and subsequent treatment of the sinter to produce alumina and potassium sulphate.

Jan 1, 1939

By M. J. Ferrante

The Bureau of Mines investigated the applicability of the freeze-drying technique for preparing dispersion-strengthened tungsten powders suitable for conversion by powder metallurgy into materials which might have improved high-temperature strength. Extruded rods from compacts of tungsten-5 vol pct thoria had at 1,650° C a tensile strength of 30,300 psi and a 10-hour stress-rupture strength of 12,700 psi, These are slightly below those measured for swaged rods of commercial tungsten-3.7 vol pct thoria. Only those tungsten-thoria dispersions containing a stoichiometric deficiency of oxygen yielded a significant strengthening effect. A low-melting eutectic formed in extruded tungsten dispersions containing either zirconia or yttria, which caused a lowering of the tensile strengths. These tensile strengths were only slightly higher than strengths of elemental tungsten made from commercial powder having a particle size of 2.4 microns (Fisher subsieve). Sheet made from this commercial tungsten had a slightly higher tensile strength than tungsten made by freeze drying, but the freeze-dried tungsten sheet had a lower recrystallization temperature, a lower ductile-to-brittle transition temperature, and a higher purity.

Jan 1, 1971

By d&apos, Kathleen J. Amico

This summary appears in Minerals Year-book volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1966

By Gabriel S. Esterhuizen, Anthony T. Iannacchione

The roof rock in underground limestone mines in Northern Appalachia can be subject to high horizontal stresses in spite of the shallow depth of the workings. The high stresses can cause roof stability problems. The National Institute for Occupational Safety and Health staff have observed a distinctive asymmetrical mode of failure at the pillar-roof contact in two underground stone mines, which is different from the typical failure mode observed in response to excessive levels of horizontal stress. A dip of greater than 5° was identified as a possible cause of this mode of failure. Numerical model experiments showed that an increase in the dip of the workings can cause an increase in the stress at the up-dip corner of the roof beam. A case study is presented in which failure at the pillar-roof contact was observed where the dip of the workings was 7° in a high horizontal stress field. Numerical modeling showed that the relatively small dip of the workings could have induced stresses changes in the immediate roof that would explain the failures. The model results also showed that this mode of failure is less likely to occur if the limestone pillars contain weak bedding planes that provide stress relief. In addition, the results showed that for the conditions at the case study site, the stress in the roof beam was not sensitive to the thickness of the roof beam or to the excavation span. The high horizontal stresses at this site are an important contributing factor to the observed failures.

By John H. Johnson

Diesel tailpipe CO, C02, NO, and N02 concentrations by the Emissions Measurement Apparatus (EMA) were found to compare satisfactorily with simultaneous concentrations by instruments in the MSHA engine certification laboratory in Bruceton, Pa. The EMA was then applied to the measurement of LHD vehicle diesel tailpipe gases and smoke opacity in the White Pine and Brushy Creek Mines. A general experimental approach was developed by which instruments could be compared for the measurement of diesel exhaust pollutant concentrations in the 1/2 to 5TLV range. The concentrations are changed by varying engine speed, dynamometer load, and the portion of the exhaust which enters the dilution tunnel. Dräger detector tube diluted exhaust CO, CO2, NO, and NO2 measurements were compared with simultaneously taken portable instrument measurements. Diesel exhaust interference inaccuracies were separated from inaccuracies due to detector tube calibration by comparing the instrument readings with both actual detector tube readings and detector tube readings corrected by recalibration of the detector tubes alongside NBS traceable calibration gases. The detector tubes' accuracy was found to be only slightly affected by diesel exhaust interferences and it was concluded that most measure within certification limits established by the National Institute for Occupational Safety and Health. The effects of 2 exhaust system configurations on the pollutant concentrations in a dead-end heading were studied. Both of the configurations exhausted the gases near the roof, directing them toward the crosscut, and both improved the stratification of the air in the heading, due to the bouyancy of the hot exhaust gases. One of the configurations was a pair of Fume Diluters which diluted the exhaust with air by a 10:1 ratio, and the second system was simply a pair of exhaust pipes, bent to direct the exhaust similarly to the fume dilutors. By redirecting the exhaust, the concentration of C02 measured on the LHD vehicle was reduced by as much as 507, in dead-end headings up to 200 ft long. The Fume Diluters showed no improvement over the simple redesign of the exhaust system.

Jan 1, 1980

By Curtis H. Elder

In studies conducted by the Bureau of Mines, two test areas were hydraulically stimulated and exposed by mining: One in the Pittsburgh coalbed at the Vesta No. 5 mine, Washington County, Pa.; and one in the Illinois No. 6 coalbed at the Inland mine, Jefferson County, Ill. Induced fractures were contained totally within the coalbed with no adverse effect on the stability of associated rock strata. Induced fractures were vertical and were propagated normal to the direction of least residual tectonic stress. Gas production was increased fivefold to twentyfold by hydraulic stimulation.

Jan 1, 1977

By Avery H. Reed

RECORD production of portland cement, crushed limestone, marble, lime, and clays highlighted the mineral industry of Alabama in 1959. Among the States, Alabama ranked second in production of bauxite, and third in output of iron ore, scrap mica, and native asphalt. Alabama's mineral industry was dominated by the mining and processing of coal and iron ore, which accounted for 51 percent of the total value of production in 1958 and 1959. Other important industries were cement manufacturing, petroleum, and stone quarrying. Leading companies were Tennessee Coal & Iron Division of United States Steel Corp. (coal;. iron ore, limestone, lime, and magnesium compounds), Southern Cement Co. Division of American-Marietta Co. (cement, lime, limestone, and miscellaneous clay) , Woodward Iron Co. (coal and iron ore), Alabama Power Co. (coal), and Ideal Cement Co. (cement lime, and miscellaneous clay) .

Jan 1, 1960