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Objective To improve seats on mine shuttle cars with ergonomic design and by reducing shock impact transmitted through the mine vehicle seat to the vehicle operator. Background Operators of underground mobile equipment, particularly shuttle cars, are often exposed to significant levels of shock and whole-body vibration. Past studies have reported that as many as one-third of underground equipment operators could be exposed to adverse levels of shock and whole-body vibration. Moreover, seats on mining equipment, historically, are inadequate relative to the ergonomic needs of the equipment operator. In the extreme, amine vehicle seat has sometimes consisted of blocks of wood or a bent steel plate bolted to the machine frame. Also, the lack of sufficient vertical clearance in some underground mines is an impediment to providing adequate shock isolation systems on mine equipment seats. Approach The NIOSH Pittsburgh Research Center (PRC) is conducting research with viscoelastic foams to improve seats on mine shuttle cars. Viscoelastic foams were used in an ergonomically designed seat to reduce the amount of shock transmitted through the mine vehicle seat to the vehicle operator. Data on selected viscoelastic foams were analyzed from laboratory shock tests at PRC. Using information from the analysis, two ergonomic seats incorporating selected foam were constructed for in-mine testing on a shuttle car (Joy 21SC) in eastern Kentucky. The shuttle car operated in a 35-in-thick coal seam with an approximate mining height of 43 in. Operational data were recorded on the ergonomic and original seats. Further, the shuttle car operator was asked to compare these seats. Results When comparing the original seat (figure 1) with the ergonomic seat (figure 2), the shuttle car operator described the ergonomic seat as generally “much better” than the original seat. The operator explained. “It’s just easy to adjust. And it’s got the lower lumbar support. And the pad is thicker. It’s just much better all the way around.” He added, “It does support you more and [there is] less shock when you hit a hole...I liked the lower lumbar support. That’s where most of your shock is at, in your lower back.” The operational data supported the operator’s comments. In the full-load case, significant improvements in isolation were achieved(down to 15 Hz) with the ergonomic seat. Additional laboratory testing of seven viscoelastic foams was done to further improve the level of isolation from shock and better characterize the material properties of each foam. Data from this testing were used in an analytical model of the seat pan isolation system. Results showed that two of the viscoelastic foams, SUN-MATE EXTRA-SOFT and PUDGEE, gave the most effective shock isolation of the seven materials tested. A composite of EXTRA-SOFT and PUDGEE foams improved the isolation characteristics of the seat pan to approximately 4 Hz. Similarly, EXTRA-SOFT by itself provided isolation to 5 Hz. These results will be validated with future in-mine measurements. Cooperative Research Opportunity NIOSH is seeking cooperators to assist in further research and development of this technology. Additional information on cooperative reseach may be obtained by contacting Jacqueline H. Jansky, Technology Transfer Officer, NIOSH Pittsburgh Research Center, P.O. Box 18070, Cochrans Mill Rd., Pittsburgh, PA 15236-0070, phone: (412) 892-6615, fax: (412) 892-6678, e-mail:jgj7@cdc.gov

May 1, 1997

By E. Shekarchi

The mineral industry of Afghanistan improved substantially in 1976 as asbestos production was begun and feasibility studies were made of possible copper and iron and steel industries. The remarkable event of the year was the introduction of Afghanistan's 7-year economic and social development plan which covered the years 2976-82. The 7-year plan established ambitious goals for a gross national product (GNP) annual growth rate of 6.3% during its duration. To achieve this target, large increases in expenditures for economic development were programed in virtually every sector of the economy. Foreign assistance, in particular, was expected to finance a large share of new development projects. The major components of the plan were the development of transportation (highways and railroads), oil and gas exploration, construction of a copper smelter to exploit the copper deposits near Kabul, and development of an iron and steel industry to exploit the rich iron ore deposits in the central part of the country. Exports during the plan period were to continue to be principally agriculture products and natural gas to the U.S.S.R.

Jan 1, 1980

By C. H. Herty

Intensive work on the deoxidation of steel with manganese-silicon alloys by the U. S. Bureau of Mines has shown that the use of those alloys, which may be produced from our domestic manganese ores, would decrease the ferromanganese requirements of a very large tone of our steel by from 60 to 30 per cent and in some cases by 100 per cent. The open-hearth heats made with these alloys have been of excellent quality. The tonnage of our ferro-grade ores which has been made available by the bureau's ore-dressing studies, combined with the ,products resulting from such processes as those developed by the bureau and by Bradley for Cuyuna ores, should easily fill our reduced ferromanganese requirements Then manganese-silicon alloys and ordinary spiegel are used in the way described in this report. There are no technical difficulties in the application of this practice, and any difficulties involved in its wide and immediate application would only be those arising from habituated ideas of the necessity of ferromangenese. General acceptance of this practice and development of the available sources of domestic ferro-grade material by already proven processes should make this country independent of foreign ores.

Jan 1, 1931

By Richard C. Repsher

Intermittent mining in the slope section at Dutch Creek No. 1 mine, Carbondale, Colo., of the Mid-Continent Coal and Coke Co. has resulted in erratic and minimal rock noise data, which, in turn, has necessitated a change in the method used to plot daily mine noise in order to be useful to the researchers at the mine. Daily and weekly cumulative plots of rock noise under these conditions have not shown significant stress changes as clearly as bimonthly or longer noise rate plots. Hence, longer term cumulative rock noise plots, as described in this Bureau of Mines report, have been added to the data analysis at Dutch Creek No. 1 mine, and have been shown to delineate unique areas of rock noise activity more clearly than shorter term plots. The longer term plots should aid in the detection and delineation of potential failure areas, when used in conjunction with other proven forms of data analysis.

Jan 1, 1979

By Michael R. Yenchek

Contacts with energized conductors are a major cause of electrocutions in underground coal mines. Sensitive ground fault interrupters (GFI's) installed on in-mine three-phase ac utilization circuits would probably prevent the majority of these deaths. A sensitive GFI is a protective device that detects and interrupts small deadly ground currents in the milliampere range before those currents can cause ventricular fibrillation in humans. Commercially available three-phase sensitive GFI's have not been specifically designed for application in coal mines. The Bureau of Mines therefore tested three commercial GFI models to determine their worthiness for mine power systems. GFI design and construction, transient immunity, reliability, and time-current characteristics were evaluated in laboratory tests. No commercial device was found suitable for mine use without design modifications. The tests results will serve as a basis for the development of a mineworthy sensitive GFI in ongoing Bureau research.

Jan 1, 1985

By Jr. Harty

Intensive work on the deoxidation of steel with manganese-silicon alloys by the U. S. Bureau of Mines has shown that the use of those alloys, which may be produced from our domestic manganese ores, would decrease the ferromanganese requirements of a very large tonnage of our steel by from 60 to 80 per cent and in some cases by 100 per cent. The open-hearth heats made with these alloys have been of excellent quality. The tonnage of our ferro-grade ores Which has been made available by the bureau's ore-dressing studies, combined with the products resulting from such processes as those developed by the bureau and by Bradley for Cuyuna ores, should easily fill our reduced ferromanganese requirements when manganese-silicon alloys and ordinary Spiegel are used in the way described in this report. There are no technical difficulties in the application of this practice, and any difficulties involved in its wide and immediate application would only be those arising from habituated ideas of the necessity of ferromanganese. General acceptance of this practice and development of the available sources of domestic ferro-grade material by already proven processes should make this country independent of foreign ores. This paper resents the results of work done under a cooperative agreement between the Pittsburgh Experiment Station of the United States Bureau of Mines and the Carnegie Institute of Technology, the Metallurgical Advisory Board, and the University of Pittsburgh, Pittsburgh, Pa.; between the Mississippi Valley Experiment Station of the United States Bureau of Mines and the Missouri School of Mines and Metallurgy, Rolla, Mo.; between the North Central Experiment Station of the United States Bureau of Mines and the University of Minnesota, Minneapolis, Minn.; and between the Rare and Precious Metals Experiment Station of the United States Bureau of Mines and the University of Nevada, Reno, Nev.

Jan 1, 1931

By W. N. Poundstone, W. M. Merritts, B. A. Light

A joint investigation by the Bureau of Mines and the Christopher Coal Co. at the Humphrey No. 7 mine, operating in the Pittsburgh coalbed in northern West Virginia, was undertaken to gain more insight concerning the hazardous emission of methane gas in mining. This report describes the equipment, procedure, and results. Horizontal bleeder holes drilled in the faces drained large quantities of methane, eliminating downtime of mining equipment. Also, larger quantities of methane were removed by forcing 14 to 25 g,.p.m. water at 25 to 200 p.s.i. 5 pressure into the bleeder holes. In one infusion test a fluorescein dye was added to the infusion water; in later mining operations, the infusion water was traced for a distance of 1,500 feet. With vacuum pump applied to the horizontal hole the gas-flow rate increased, and the methane content decreased. Tests indicated that methane and water infused in bleeder holes traveled along the bedding planes of the Pittsburgh coalbed at a faster rate than across the planes. Methane associated with coalbeds is produced by the slow decomposition of carbonaceous material in the absence of air and the presence of water. It is lighter than air and, depending on its concentration, forms an inflammable or explosive mixture with air. It is believed that methane is entrapped in and around the pores of the coal and adjacent strata--often under great pressure. In many cases where the strata have been disturbed by geologic movements the

Jan 1, 1962

By A. L. Murray

"Welfare endeavor in connection with both the metal and the coal mines of Utah has shown gratifying progress during recent years, and in most mining towns of the state, both the operators and their employees deserve much credit for the efforts put forth to better the living, working, educational and recreational conditions. Progress has been and is being made, but there are still a few important towns where purer water and better sewage disposal are pressing needs.In the older metal-mining towns that are incorporated and are independent of the mining properties operating in the vicinity, less opportunity is presented for the companies to exercise efforts looking toward improved welfare conditions than in company towns controlled by the mine operators.However, even in such towns the companies can do much to better welfare conditions, as shown by the progress in Bingham Canyon during the past several years. The Utah Copper Company has spent $800,000 since 1920, in the erection of modern brick cottages, apartment houses and the Germnell Memorial Club. The cottages and apartment houses have every convenience to be found in up-to-date city homes. The Gemmell Memorial Club erected and equipped at a cost of $175,000 was provided by the company for the benefit of the Utah Copper employees living in the canyon and has been made the recreational center for the camp. Another improvement is the $100,000 fireproof hotel built by the United States Mine of the United States Mining, Smelting and Refining; Co. in the Copperfield section of Bingham Canyon. This hotel will accommodate 105 men exclusive of hotel help and has all the conveniences of a city hotel."

Sep 1, 1925

To provide a means for rapidly evaluating proposed mine layouts in order to avoid potential hazards while minimizing loss of coal. The Approach: Development of a computer program that will compute many possible mine layouts by changing the mine plan until the arrangement giving minimal hazards with optimum extraction is found. How It Works: The Hazard Evasion Program for Mine Planning, developed by the Bureau's Denver (Colo.) Mining Research Center, tests hundreds of possible solutions to a mining layout, and by sorting out the 10 best (based on the criteria of maximum safety for workers with minimum abandoned coal), limits the number of choices that need to be considered and appraised for applicability to a given mine scheme. The program is applicable for room and pillar or longwall mining, for oil and gas well hazards, and for other hazards that can be described mathematically such as channel sands, potential bad roof areas, faulting, voids, or water pockets.

Jan 1, 1974

By J. Davitt McAteer

Dear Mine Operator, Training for new employees, refresher training for new employees, refresher training, and new task training can mean the difference between life and death for workers. Part 46 spells out how you can develop a training program to protect workers for on-the-job hazards. Together, labor, industry, and the U.S. Department of Labor reached a milestone with the development and publication of Part 46. We want to continue working together toward the next milestone, October 2000, when the regulations take effect. We want to make sure you have all the information you need about these new training requirements. Throughout the next 12 months, MSHA personnel will be holding regional meetings across the country, delivering information and sample training plans to your operation, and offering you help to develop your plan. If you are among the many operators who are already providing training to your workers, keep up the good work. The rule will tell you exactly what is expected. If you currently have no training program, we can help you develop one. A brochure is being distributed, which highlights the main provisions of the rule. It is designed to introduce the rule to you. More detailed materials will be delivered to you. If you want information right away, simply call us, or e-mail us. We also welcome your comments, suggestions, and success stories. Part 46 will be successful and beneficial to miners through our combined efforts. Together, we can make our mines safe and healthier for everyone. Sincerely, J. Davitt McAteer, Assistant Secretary of Labor Mine Safety and Health Administration

Jan 1, 1999

By K. J. Liles

To encourage the development and conservation of the Nation's ceramic raw materials, the Bureau of Mines, U.S. Department of the Interior, under an agreement with the Georgia Department of Natural Resources, evaluated samples from a clay resource located in Clay County, Ga., for use as a raw material for lightweight aggregate. The physical properties of clay samples, taken from 5-foot increments of drill cores from 11 holes, were determined. Raw materials were plasticized and extruded to produce 1/2-inch by 1-inch pieces and fired in a rotary kiln to produce lightweight aggregate samples. The resulting expanded material had excellent loose pour weights ranging from 30 to 37 lb/cu ft. The expanded test materials were crushed, sized, and used as aggregate to form concrete cylinders. The unit weight and compressive strength of the cylinders averaged 106 lb/cu ft and 3,350 lb/sq in, respectively; these values meet American Society for Testing and Materials specifications for structural concrete. The clay from the drill cores was also used to make test bars that were evaluated for building brick.

Jan 1, 1980

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine if primary gas toxicities that evolve during the early (~300° C) and later (~.400° C) combustion stages of polyvinyl chloride and chlorinated brattices could be predicted by a smoke particle characteristic, which could be used as a simple and inexpensive test parameter. The experiments were conducted in an approximately 20-L furnace at set furnace temperatures of 2500 and 1,0000 C, for 14 min duration, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were the hydrogen chloride (HCl) and carbon monoxide (CO) concentrations, sample and furnace temperatures, the sample mass weight loss, the average smoke particle diameter (dg and number concentration (no), and the product of the average smoke particle diameter and concentration (dgno)' Results show that the inverse of the smoke particle diameter-concentration (l/dgno) correlates directly with the primary gas toxicities evolved during both stages of combustion.

Jan 1, 1989

By G. E. McElroy, A. S. Richardson

"The Bureau of Mines, in cooperation with the Anaconda Copper Mining Co., has conducted a series of experiments an air measurement in fan-pipe installa¬tions in a Butte mine during the fall and winter of 1922-3. The chief purpose was to determine the friction factors for different types and sizes 3f fan piping, but much attention was devoted to methods of air measurement, not only with respect to the methods used for friction factor tests, but also to com¬parison with other methods.The air flow was measured simultaneously at two points 380.6 feet apart in six different fan-pipe installations, each over 500 feet in overall length, in a rock cross cut adjacent to an air shaft,The air pressure was regulated by two sinoco multivane fans, driven by 7 ½ h.p. motors, the fans being connected in tandem so that one discharged into the intake of the other through a short connector and the latter discharged into the line through a straight connection equipped with a honeycomb of 4-inch squares or S radial vanes to prevent spiral flow of air, At each point where it was desired to measure the air flow, measuring sections equipped with piezometer rings pierced for easy insertion of pitot tubes, thermometers, etc. Piezometer static pressures were used in all the tests as standard, and dynamic or total pressures only were obtained with the pitot tubes, except for purposes of comparison.The tubes had special guide blocks, designed especially for underground work. To insure greater accuracy two tubes were used simultaneously, in order to obtain the velocity pressure at the center of the section simultaneously with that nearer the circumference, so that the mean velocity would be determined as accurately as possible. The tubes were held in proper place by means of flat guide boards. Velocity pressures were measured in manometers."

Sep 1, 1923

By Todd M. Ruff

Current methods of inspecting wire rope for broken wires or excessive wear include visual inspection, physical measurements of rope diameter, and electromagnetic nondestructive testing (NDT). Visual inspection and physical measurement arc the least comprehensive methods. Electromagnetic NDT enables a more thorough assessment of the condition of a wire rope, but the repeatability, accuracy, and objectivity of this method can be improved. One means of achieving this goal is to use a computer to analyze the test data and determine the condition of the wire rope, including the presence of broken wires and corrosion, and the amount of wear. An off-the-shelf data acquisition and analysis system was tested in a U.S. Bureau of Mines laboratory using a continuous loop of wire rope containing fabricated flaws. The test rope was run through a commercially available NDT instrument. The output of the instrument, normally connected to a paper strip chart recorder, was digitized and analyzed with a personal computer. These initial tests were successful in showing that the use of a computer can improve current methods of NDT waveform collection and analysis.

Jan 1, 2010

By Richard J. Mainiero

Traditional techniques for the experimental determination of toxic fumes produced by the detonation of high explosives are not applicable to blasting agents. To detonate properly, blasting agents require confinement, a significant booster, charge diameters of 3 inches (7.5 cm) or greater, and charge lengths greater than two-times the charge diameter. Without these conditions, blasting agents will not detonate at full order, leading to a misrepresentation of the gaseous products. A facility for detonating large, confined charges in a controlled volume has been constructed at the Pittsburgh Research Center’s Experimental Mine. The facility consists of a portion of mine entry (once used for full-scale mine explosion research and demonstrations) enclosed between two explosion proof bulkheads. Total volume of the chamber is 9,666 ft (274 m). The chamber is equipped with an air circulating system and is3 3vented using the mine's airflow. Up to 10-pound (4.5-kg) charges can be detonated in the chamber using a variety of confinements. For a typical test, the blasting agent is confined in a 4-inch (10-cm) schedule 80 steel pipe and initiated by a 3-inch (7.5-cm) diameter, 1-inch (2.5-cm) thick Pentolite booster. This combination of confinement and initiation yields a detonation velocity of about 4,000 m/sec for ANFO. This velocity is in line with that measured for blasting in the field. Twenty four 2-inch thick steel plates are suspended around the pipe bomb to stop shrapnel that would otherwise seriously damage the chamber. Following detonation of an explosive in the chamber, a circulating fan is run for about 10 minutes to uniformly mix the chamber atmosphere. Fumes samples are taken out of the chamber through 1/4-inch (0.6-cm) Teflon or polyethylene2tubes for analysis. The fumes are analyzed using bubblers or Vacutainers to collect samples for analysis by the analytical chemistry lab. The technique described here has been employed to determine the fumes produced by the detonation of a variety of ANFO formulations and commercial explosives. This technique may be developed as a standard test to measure fumes produced by blasting agents or may be used to provide data with which to develop a computer model that will reliably predict the expected fumes production based on chemical composition.

By James J. Olson

Previous Bureau of Mines studies of vibrations from quarry blasts have shown that the square root of the charge-weight may be used to group particle velocity data from various charge sizes, and that empirical propagation equations may be used to estimate vibration amplitudes. Particle accelerations of the sandstone roof of the White Pine Copper mine, Michigan, were measured to determine whether similar propagation equations may be developed for underground mine blasts. Vibration data from White Pine blasts were best grouped by scaling with the square root of the charge weight. Cube root scaling did not effectively group the data. The empirical propagation equation AW1/2 = 50,000 (R/W1/2)-2.21 where A is peak-to-peak acceleration in g's, W is the zero-delay charge-weight in pounds, and R is the distance from the blast in feet, may be used to estimate maximum vibration amplitudes from production sized blasts. Vibration differences among headings and types of explosive charge (AN-FO and dynamite), while statistically significant, were not a major factor in the estimation of maximum vibration amplitudes with an empirical propagation equation. Vibration differences between types of explosive charge were larger than the differences among headings, indicating that some reduction of vibration amplitude might be gained by using AN-FO rather than dynamite. Acceleration records from both White Pine's AN-FO and dynamite production blasts show that high intensity vibrations from the delayed portions of the blast (each delay interval = 25 milliseconds) were separate events, and that the zero-delay portion of the blast produced the maximum vibration amplitudes. If the pull of the underground blast round can be maintained, a reduction of the zero-delay charge-weight may effectively reduce the maximum vibration amplitude of the blast.

Jan 1, 1970

By L. H. Lange, F. F. Hintze

"Mineralogical Composition of Cyanite RockIn the group of minerals used in making this study, the cyanite is associated with quartz, mica, and feldspar in the schist. The amount of quartz is variable, but it is always an abundant mineral. Both large and small crystals of quartz occur in irregular masses, rarely ever showing crystal outline. Mica is of the clear and dark varieties the larger crystals being dark as a rule, and the finer crystals of light color, The present mineralogical composition of the mica is rather variable as most of the original biotite and muscovite have suffered alteration, and much secondary mica is present as a result of alteration of the original mica and other minerals present, especially the larger cyanite crystals. A large part of the mica now found in the ore is chlorite, with varying amounts of Jefferisite and others, especially sericite. These are in the form of aggregates, or felt-like intergrowths filling the spaces between the quartz, cyanile, and feldspar.The feldspar is plagioclase probably mostly albite. It is white, possesses good cleavage, and is one of the hard brittle minerals of the rock. It alters to kaolin, and sericite, and more or less of these alteration minerals are present within the feldspar crystals but not separated from them.The cyanite is of two varieties, distinguished by their colors as blue and white cyanite. The blue color varies in intensity, being a pronounced blue in some crystals and paler in shade in others. Some crystals have been seen which possess the blue color in one-half of their mass and are pure white or clear in the other half. The purity of the cyanite is probably not affected by the color, but it is difficult to detect the white cyanite in the ore by macroscopic examination, so that great care has to be exercised in the selection of the ore in the field."

Apr 1, 1931

By Charles E. Munroe

On March 14, 1921, an explosion occurred at about 6:15 A.~. on the premises of an iron-mining concern throug:1 which two magazines, one containing upwards of 9,000 pounds ot a high explosive of the dynamite class, and a second, 60 feet distant, containing upwards of 10,000 No. 6 detonators, were completely destroyed, and a ncratertt,? f3et deep by 30 feet in diameter, was excavated in the gro~ at ~he place whare the mag~iine containing the high explosive had been lo~ated. As a rule any eye wit~esses to the circumstances im.~ediataly preceding and d(irectly concurrent with a.c.ci.:lental ex;losions ar.e victims of s11ch explosions, and, therefore, the conclusions reached as to the cauoa. of such explosions must, perf'orce, be based aln:ost completely on circumstantial evidetJ.ce. In this iii.stance, b:ecause both the explosive and detonators were of -orov{:;d: character; because of the time of the day and the state of operations iit the·· time of the e:.q,losion; because the rerroteness of the location of the n:-1agazi::1es 1 0::1 the side of a ravine, easily admittfi of unobserved approach; beca:iise differencas existed, and because no obvious cause was at once apparent, there arose suspicfon that the explosion was not accidental.

Sep 1, 1921

"Fire fighting in metal mines under the best of conditions is a dangerous, a slow, and a difficult task. Certain gases generated from combustible material burning in restricted areas are poisonous, even in small quantities, and can not be breathed without serious and often fatal results. In addition to poisonous gases, smoke is given off which obscures the vision of the fire fighter and frequently prevents him from gaining access to the fire area. Many fire-fighting crews have had to turn back because their vision was so impaired by the dense smoke that the fire area could not be located and there was danger of them becoming lost in the mine.In mines having mechanically controlled ventilation - that is, mines not dependent entirely upon natural air currents - the gas and smoke can be forced ahead of the fire-fighting crews, thereby facilitating exploration of the mine and saving the time, energy and oxygen of the mine rescue apparatus crews.Where currents of fresh air can be circulated up to points near the fire without danger of seriously spreading the fire, fresh air bases can be established in the immediate vicinity, and a more intelligent campaign for fighting or controlling the fire can be mapped out.Positive air currents through forced ventilation may also result in saving the lives of miners who otherwise might have been trapped in smoke and poisonous gases.It is generally known that comparatively few metal mines have attempted to regulate or control air currents, with the result that when a fire occurs underground, the normal ventilation may be reversed, short circuited, or the air current may be in one direction one minute and in the opposite direction the next; or, generally speaking, the ventilation can not be depended upon, and smoke and poisonous gases may accumulate in any part of the mine or ""drift"" on the fire-fighters or on the miners endeavoring to escape."

Apr 1, 1921

By Oleg Terichow

The Bureau of Mines studied the penetration of a slender cylindrical tube into a sand bed, simulating seafloor material under the application of a static load. The factorial experimental design was based on three factors: tube diameter, geometry of penetrating bit, and seawater saturation of sand, all of which were found to be significant in influencing the depth of penetration. The geometry of the penetrating bit, or shoe, is of major significance in the mechanics of penetration and should be considered the most important factor for additional study. Linear regression analyses of the load-penetration data show that the relationship is linear.

Jan 1, 1970