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This Volume documents the Phase 111 effort on the Seismic Detection and Location of Isolated Miners on Contract H0122026 undertaken during the fall of 1972 by a task team composed of ADL staff and several seismic consultants. The team was assembled specifically to work together on complementary tasks, at an accelerated level of effort for four months, to meet the Bureau of Mines' time schedule for obtaining independent, objective, technical judgments regarding seismic methods and systems for detecting and locating isolated miners. The impetus for this work resulted from a compilation and analysis, during the first half of 1972, of new experimental data obtained from a series of in-mine field tests conducted by Westinghouse Corp .+ using the CMRSS* interim seismic location system. The Bureau of Mines took advantage of the availability of these new data to reassess the potential and limitations of various seismic methods and systems, and to direct its seismic system improvement program accordingly. ADL assisted the Bureau in this reassessment by drawing on the skills of seismic consultants from industry, universities and government, to supplement the skills of the ADL project team. The consultants were principal resources of broadly-based and detailed technical expertise in the areas of seismic signal-source and signal-propagation characteristics, natural and cultural seismic noise, seismic sensors and field instrumentation, seismic signal and data processing for detection and location, and overall seismic system utilization in the field under operational emergency conditions. Specifically, the participating consultants were: F. Crowley, Air Force Cambridge Research Laboratories ; W. Dean, Teledyne Geotech, Alexandria Laboratories; R. Greenfield, Pennsylvania State University; J. Kuo, Columbia University; D. Peters and R. Crosson, University of Washington; and F. Pilotte, U.S. VELA Seismological Center. The principal ADL participants were J. Ginty, R. Lagace, M. Roetter, and R. Spencer.

Jan 1, 1974

By R. A. Keaens, L. C. IlsLey

For the purpose of this paper a junction box is defined as " a fused switch, inclosed in an explosion-proof compartment, provided with a ready means of connecting or disconnecting a trailing cable without exterior arcing." Junction boxes are intended for use 'at the end of trailing cables and are usually placed outby the last open break through in a coal mine. Where it is not safe to supply current through nips or a trolley, junction boxes suitably spaced along an entry permit tramming and movement of machines with safety, although not with any considerable speed. Junction boxes serve a threefold purpose: (1) They prevent dangerous arcing at the outby end of trailing cables; (2) they afford a safe, practical means of fusing or otherwise protecting the trailing cable; and (3) they provide an efficient means of transmitting power from the power circuit to the trailing cable. The first purpose is the most important from a safety standpoint. Dangerous arcing-that is, arcing capable of igniting gas-frequently takes place where trailing cab1c.s are attached to the power circuit. At either 250 or 500 volts only a very small arc is required to ignite mine gas. The usual method of connecting the trailing cable to the power circuit by cable nips or trolley taps does not make a good electrical connection; hence arcing may be expected at any time. Furthermore, junction boxes eliminate the personal hazard attendant upon the use of trolley taps by removing the possibility of accidental contact with trolley hooks or wire and the liability to injury due to manipulation of the device. In the general scheme of mine ventilation it is assumed that gas will not accumulate where junction boxes are placed, an assumption based on the normal operation of the ventilating system. In many

Jan 1, 1929

By Eric S. Weiss

The National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) conducted joint research to evaluate explosion blast effects on typical U.S. mine ventilation stoppings in the NIOSH Pittsburgh Research Laboratory?s (PRL) Lake Lynn Experimental Mine (LLEM). An innovative Australian-designed brattice stop-ping was also evaluated. After mine explosion accidents, MSHA conducts investigations to determine the cause(s) as a means to prevent future occurrences. As part of these postexplosion investigations, the condition of underground stoppings, including the debris from damaged stoppings, is documented as evidence of the approximate strength and the direction of the explosion forces. The LLEM data showed that a typical dry-stacked and coated solid-concrete-block stopping survived a total explosion pressure of ~6.7 psi (~46 kPa) and was destroyed at a total explosion pressure of ~7.6 psi (~52 kPa). In comparison, a typical dry-stacked and coated hollow-core concrete block stopping survived a total explosion pressure of ~3.4?4.3 psi (~23?30 kPa) and was destroyed at a total explosion pressure of ~3.6?5.2 psi (~25?36 kPa), depending on the length of the pressure pulse and the value of the pressure-time integral. A typical steel panel stopping design survived a total explosion pressure of 0.8 psi (5.5 kPa) and failed at a total explosion pressure of 1.3 psi (9 kPa). The LLEM data also showed that an obstacle blocking the path of a pressure wave resulted in a higher reflected pressure at the obstacle. An 8-in (20-cm) thick wet-laid solid-concrete-block stopping coated on one side survived a total explosion pressure of ~26 psi (~180 kPa); this stopping was not tested to failure. A 6-in (15-cm) thick wet-laid solid-concrete-block stopping coated on one side survived a total explosion pressure of ~14 psi (~97 kPa) and was destroyed at a total explosion pressure of ~25 psi (~172 kPa). An innovative Australian woven cloth stopping survived an explosion pressure of 4.0 psi (27 kPa) and was destroyed at an explosion pressure of ~6.1 psi (~42 kPa). These results will help investigators determine the approximate explosion forces that destroy or damage stoppings during actual coal mine explosions.

Jan 1, 2008

By Virgil A. Marple, Susanne V. Hering

"5.1 IntroductionTraditional impactors do not offer much size resolution for submicrometer particles; typically their finest size cut is around 0.4 µ.m. Yet for many aerosol applications it is useful to be able to size segregate aerosols in the size range below 0.4 µ.m. Diesel emissions, welding fumes, cigarette smokes and photochemically generated smog aerosols typically exhibit mass median diameters between 0.1 and 0.6 µ.m. When sampling these aerosols with a traditional impactor, fifty percent or more of the aerosol mass can penetrate the final impactor stage. Allhough the material can still be collected on a backup filter, the filter gives no size resolution. As a result, the investigator has no size information on a substantial portion of the sample. One needs a sampler that size-segregates the majority of the aerosol mass. A lower size cut of 0.1 µ.m or less is required for most combustion smokes and smog aerosol s.To obtain smaller cutpoints two types of impactors have been developed, namely low-pressure impactors and micro-orifice impactors. Both instruments can provide cutpoints as small as 0.05 µ.m. Low-pressure impactors were introduced more than twenty years ago (Stem et al., 1962), and a variety of these samplers are in use today. Micro-orifice impactors have been developed at the University of Minnesota within the last five years (Marple et al., 1981 ). To date theirs are the only examples of these instruments in use.5.2 Operating PrinciplesThe low-pressure and micro-orifice impactors use two different approaches to achieve their very small particle-size cuts. Low pressure impactors resemble ordinary impactors, but are operated at reduced pressures of 5-40 kPa (0.05 - 0.4 atm). They take advantage of the decreased aerodynamic drag on particles that occurs when the mean free path in the air is as large or larger than the particle diameter. Micro-orifice impactors operate at near atmospheric pressure, but employ very small orifices, 40 µ.m to 200 µ.m in diameter. The streamlines of the air impinging upon the impaction plate have correspondingly smaller radii of curvature; the air is accelerated more quickly, making it more difficult for the particles to follow. The basic operating principles for both types of impactors are evident from the particle Stokes number, defined as:"

Mar 1, 1989

By J. D. Davis

"Introduction.Sixty years ago, M. Berthelot found that ethylene could be selectively absorbed from gaseous mixtures by concentrated sulphuric acid, and that the compound formed by the chemical union of the gas and acid was readily decomposed by heating with water, yielding ethyl alcohol. Only within the last few years has there been any attempt to make use of this discovery technically.Bury*, working in England at the Skinningrove Iron Works and on a commercial scale, developed a technical method for converting, the ethylene of coke-oven as into alcohol. With a gas containing less than 3 per cent of ethylene, he obtained a yield of 1.6 gallons of alcohol per ton of coal carbonized.De Loisy** perfected a technical method for treatment of coke-oven as for alcohol. Evidently this work was carried out on a semi-commercial scale. His method is based on the use of catalytic agents for hastening the absorption of ethylene by sulphuric acid. He uses part of the spent acid for drying the gases and pact for the manufacture of ammonium sulphate. Excess acid is reconcentrated by waste heat. Others have worked on the problem, but so far there has been no large recovery of ethylene from coke-oven gases. The chief difficulty seems to lie in the low efficiency (about 50% of methods and tae relatively low concentrations of ethylene in the gases treated. Gas from Trent amalgam*** contains much larger percantages of ethylene than does coke-oven gas, as Will presently be shown, and if it should ever prove practIcal to treat industrial ;as for alcohol, this gas would offer attractive possibilities,* Bury, Ernest, Ethylene as Alcohol from Coke-Oven Gas: Gas Journal' Vol. 148, D. 30, 1919, pp. 718.** DC Loisy, M.E., Sur un procede' industrial de fabrication syntlotique de l'alcool et de l'ether a partir des gaz de distillation de la houil Comp Rend, vol. 170, Jan. 1920, p. 50-3.*** A paste consisting of approximately part oil such as that obtained as for cleaning coal. See Perrott. in cleaning coal, Chem 3 parts finely pulvarized coal and 1 final product in the Trent, process StJ, and Kinney, S.P. The use of oil Vol. 35 August 3, 1921, p, 183.. & Met."

Nov 1, 1922

By Steven J. Page, John A. Organiscak

The amount of airborne respirable dust generated from break- age of different coals varies widely. This research was conducted to identify the facets of airborne respirable dust liberation from the coal product. Laboratory crushing experiments were conducted on a range of low to high volatile bituminous coals to investigate the various factors influencing airborne respirable dust generation. Bituminous coal samples from 8 mines (5 U.S. and 3 Polish) were uniformly prepared and processed through a double roll crusher located in a low air velocity wind tunnel. Experimental factors studied included inherent coal seam constituents, specific energy of crushing, product size characteristics, dust cloud electrostatic field, and specific quantity of airborne respirable dust generated. The results of this investigation build upon previously published results, which indicated that a combination of several factors are associated with the generation of airborne respirable dust. One factor involved is the effect of coal rank, described by the inherent moist fuel ratio, on the product size characteristics, defined by Schuhmann size function parameters. However, since coals of high moist fuel ratio (high rank) are generally more extensively cleated, it is suggested in the present work that the degree of cleating is directly responsible for the quantity of respirable-sized particles produced in the crushed product material for eastern U.S. coals. This is implied by the relationship of ash content and at least one mineral constituent (pyrite, determined from pyritic sulfur analysis) to the percentage of airborne respirable dust. To validate this hypothesis, a description is offered that is based on known coal petrography. Another key factor is the effect of air dry loss moisture in the coal seam on the breakage-induced electrostatic field of airborne dust. The air dry loss moisture factor appears to control the amount of airborne respirable dust that is liberated from the product. The resultant effect of these factors is that different percentages of coal particles smaller than 10 µm are dispersed as airborne respirable dust with a well-defined peak in the normalized airborne respirable dust for a narrow range of air dry loss moisture - ash ratios. A clear delineation of coals, based on well-known proximate analysis characteristics, that generate the most respirable dust appears to be possible. It was also shown that the dust-generating characteristics of coals could be reasonably described by both the moist fuel ratio

By Bob Thomas, Syd Peng, Quanzhong Gu, Gene Wilson, Gerald L. Finfinger

Identifying the properties of overlying rocks in underground mining operations is important to ensure the appropriate roof support design is used to maintain stability of the mine entries. Recently J. H. Fletcher & Co. developed a monitoring and control system for roof bolters for the underground mining industry. The system records the drilling parameters used during roof bolt drilling and the information can provide insight into the physical properties of the roof strata. The parameters include thrust, rotational speed, torque and velocity and the measurements are collected every 0.1 second during the operation. The drilling parameters were analyzed to determine the application of identifying the strength of rocks being drilled from the measurements. The data was converted into the specific energy of drilling which is a measure of the amount of energy required for removing a given unit of rock during a drilling operation. The laboratory studies completed to date indicate a fairly high correlation between the specific energy of drilling and the unconfined compressive strength of :he rocks that were drilled. Additionally, the drilling parameters were shown to be effective for identifying the presence of fractures or bed separations between rock layers. The thrust, torque and specific energy of drilling were all good indicators for identifying the fractures or separations. Regardless of the drilling parameters used during the drilling experiments, the location of the fractures were identified. In order to determine the application of the drilling parameters for identifying roof rock properties, two series of experiments were conducted. The first series of experiments used three "manufactured" roof layers that had various rock samples embedded in concrete blocks. The rock samples included three types of sandstone, marble, and argillite. Another concrete block was poured with foam inserts to simulate large bedding separations (2 to 8-in). Two other manufactured blocks were constructed using high-strength concrete with cardboard layers embedded to simulate smaller fractures or bedding separations. The size of the cardboard layers varied from 1/8- to 1-in thick. One of the blocks had the cardboard layers embedded at an inclined angle to determine the effect of the orientation on the drilling parameters. A series of experiments was conducted with the rotational speed and the penetration rate held constant and the thrust and torque allowed to vary. The information collected from the experiments is used to determine the application of the drilling parameter measurements for identifying rock properties, fractures and bedding separations.

By Peter Kovalchik, Ed Kwait, T. Michael Durr

1. BACKGROUND Many research projects on engineering controls for noise reduction in mining were conducted by the former U.S. Bureau of Mines, mostly under contracts from 1972 through 1986.1 Contracts were awarded to determine which mining equipment was responsible for worker noise exposure over the permitted Federal Regulation level of 90 dBA for 8 hours. Dominate noise sources, for each piece of equipment was also determined. The final goal was to develop engineering noise controls for those pieces of equipment and then evaluate them. This was the general approach taken in each research project or contract. This paper deals with what is known about the control of noise from continuous miners, one of the most commonly used underground mining machines. A literature review on continuous miners revealed that the relevant noise sources were divided into four categories: conveyor, cutting head, drive train, and motor noise. The dominate noise sources reported were the conveyor noise and the cutting noise.2 Conveyor noise consists of impacts and scraping at various locations on the conveyor structure. These impacts are associated with discontinuities on the top and bottom decks, impacts between the chain and the tail roller, impacts on the sidewalls at path points of discontinuity under horizontal pivot, and impacts on the flex plate.3 Scraping occurs along the entire length of the chain conveyor. The other dominate source, the cutting of coal, has also been addressed in past research.4, 5, 6 The research presented in this paper only addresses the controls associated with the conveyor. The literature suggests several effective treatments for noise control: retrofitting the chain conveyor with a urethane coating or a urethane sleeve on the chain flights, using a urethane coating or urethane sleeve on the tail roller, constrained layer damping of the decks, and the use of a modified take up plate.7, 8 However, the in-mine durability of these concepts has yet to be proven for the conveyor system. This paper analyzes extensive noise and urethane durability testing on a Joy 14CM9 continuous miner’s conveyor assembly, tail roller, and bottom plate conducted at the Pittsburgh Research Lab facilities. It will also discuss the initial underground testing results for the urethane-coated conveyor flights and tail roller.

By Corwin L. Cooper

This vapor, which describes mining and milling methods and costs at the Knob Hill gold mine, is one of a series being prepared by the Bureau of Mines on gold mining and milling practices in the United States. The mining properties owned or controlled by Knob Hill Mines, Inc., are situated in the Eureka mining district on a country road 2 miles up Eureka Gulch from the town of Republic, county seat of Ferry County, Wash. The district is about 140 miles northwest of Spokane by road and 35 miles south of the international boundary line. The altitude at the mine office is 2,700 feet.

Jan 1, 1940

By R. S. Fowkes

A study was made by the Bureau of Mines of the penetration of selected granular materials in an unconfined state by wedge-shaped tools having dimensions comparable with the dimensions of the particles composing the materials. The output force for larger particles fluctuated radically. A custom-designed integrator was used to obtain work as a function of depth of penetration in the form of smooth curves. The influence of wedge angle, depth of penetration, penetration rate, entry angle, compaction state, and particle size on the force required and the work performed was ascertained. Empirical equations describing force and work as a function of penetration were obtained for each set of experiments.

Jan 1, 1973

By David D. Hottinger

Only a minimum amount of illumination is generally provided for many types of mobile surface mining equipment. This condition presents a hazard to operating personnel working on and around such equipment. To reduce this hazard MSHA has proposed safety regulations requiring minimum levels of illumination for hazardous zones on and in the immediate area surrounding surface mining equipment. This report describes a Bureau of Mines sponsored project demonstrating the feasibility and effectiveness of providing dragline illumination in compliance with the proposed MSHA regulations. A description of the computer aided design, on site installation and field evaluation of individual lighting systems for each of three different size draglines is presented

Jan 1, 1981

By Pedro Lilienfeld

The objective of this program was the development, design, and fabrication of six personal-sized completely self-contained dust monitors capable of real-time as well as time-averaged monitoring of the concentration of respirable particles in coal mines, in the range of 0.1 to 100 mg/m3. The operation of these monitors is based on light scattering and passive air sampling. The design stressed overall miniaturization, ruggedness, simplicity and versatility. These instruments incorporate a single-chip CMOS microprocessor to perform all signal processing, data display and storage, and timing functions. The overall dimensions of these devices are, approximately, 10 by 10 by 5 cm.

Jan 1, 1982

By N. Kyriazi

A performance study of oxygen self-rescuers from the United States and other countries was undertaken as an assessment of present worldwide technology. The apparatus were tested a an breathing and metabolic simulator in the Life Support laboratories of the Bureau of Mines. Parameters monitored during the testing were inhaled levels of C02 and 02, inhaled gas temperature, and breathing resistance. The metabolic demand placed on the apparatus represented the average demand of the 50th percentile miner performing a 60- min man-test 4, as described in 30 CFR 11H. Results presented include ;apparatus service life and subjective comments as well as averages and peaks of monitored parameters.

Jan 1, 1984

By R. E. Perry

To develop new or improved flotation methods for beneficiating low-grade red iron ores, the Bureau made many bench scale and continuous anionic flotation tests on ferruginous sandstones and calcareous iron ores from the north-eastern part of the Birmingham, Ala., iron district. The ores contained about 21 to 36 percent iron, a to 11 percent lime, and 22 to 64 percent silica. Production of iron concentrates containing 48 to 52 percent iron was technically feasible in batch tests, and the iron recoveries ranged from 85 to 92 percent. In continuous tests 49 to 51 percent iron products were obtained with 80 to 90 percent recovery.

Jan 1, 1962

By Wm. O. Vanderburg

This paper describing the mining practices at the Block P mine of the St. Joseph Lead Co. at Hughesville, Mont., is ore of a series of similar papers being prepared by the Bureau of Mines on mining practices, methods, and costs in the various miner of the United States. ACKNOWLEDGMENTS In the preparation of this paper the writer acknowledges the assistance of R. H. Willcomb, general manager, William Thorson, mine superintendent, and B. P. Bellport, mining engineer, of the Hughesville division of the St. Joseph Lead Co.; and of E. D. Gardner; supervising engineer, U. S. Bureau of Mines, Southwest Experiment Station, Tucson, Ariz.

Jan 1, 1931

By J. G. Donaldson

A bench-scale method for recovering lead and zinc from slimes and mill tailings from the Tri-State District of Missouri, Oklahoma, and Kansas was developed by the Bureau of Mines. Dilute hydrochloric acid, containing sodium chloride, and chlorine gas were used to decompose the mineral constituents. Lead was electrolyzed from the pregnant acid solution, and zinc was precipitated from the depleted electrolyte by neutralization with lime. Up to 98 percent of the lead was recovered in an impure lead electro- deposit assaying approximately 85 percent lead. Zinc recoveries up to 90 percent of the total were attained in a precipitate assaying approximately 40 percent zinc.

Jan 1, 1963

By J. J. Jakosky, D. H. Zellers

"IntroductionThe Bureau of Mines has been conducting experiments in underground communication during a period of several years, and a brief summary of what has been done is as follows:During 1919-1920, investigations were conducted with the geophone. This instrument was used extensively during the World War for detecting enemy digging and mining operations, by means of the vibrations transmitted through the earth strata.A preliminary investigation using short wave-length (200 to 300 meters) radio equipment carried out jointly with engineers of the Westinghouse Electric & Mfg, Co. during 1922.The step was to investigate ground conduction signaling, (called T.P.S. in Signal Corps parlance)."

Nov 1, 1924

By Wilbur L. Webb

This publication reports on the design, fabrication and test of an Improved methane monitor system for compliance to 30CFR75.313. The system will Initiate automatic shutdown of mining machinery when excessive concentrations of methane are encountered. The prime consideration: In the design were small size, Improved accuracy and reliability, fast response and a transient resistant power supply capable of reliable operation from any mine power source. The power supply contains an internal battery that provides operating power to the detection system prior to mining machine start-up or after machine shutdown. This report documents the development program from conception through in-mine testing.

Jan 1, 1978

By Robert F. Droullard

The Bureau of Mines has investigated techniques of using gross alpha or beta detectors to continuously measure working levels. Both methods measure radioactive particulates collected on a filter paper using a constant airflow. Inherent-error studies indicate a value of about ±3 percent for the gross alpha method and about ±8 percent for the beta method in typical mine atmospheres. However, the beta method avoids problems associated with alpha detectors and is therefore more useful. Applications of these continuous working-level detectors include work area monitoring of exposure levels in underground openings, such as mines and caves, and calibrating personal dosimeters exposed over extended time intervals.

Jan 1, 1977

By F. D. Everett

The Burgin shaft of Bear Creek Mining Co. near Eureka, Utah, was sunk during 1956 and 1957 as part of an exploratory program, searching for lead, zinc, copper, silver, and gold ore bodies hidden from the surface by several hundred feet of volcanic rocks. This paper describes the sinking methods and operating practices of Centennial Development Co., contracting firm for Bear Creek Mining Co., in sinking a 3-compartment vertical shaft 1,100 feet. The operation featured the Cryderman positive-action, clam-type shaft mucker. The shaft was completed in 142 days by a shaft crew of 10 men and a top force of 10 men, including supervision.

Jan 1, 1959