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By D. R. Babich, E. R. Bauer

National Institute for Occupational Safety and Health (NIOSH) researchers are conducting a cross-sectional survey of equipment noise and worker noise exposures in the mining industry. Surface and underground limestone is one commodity recently surveyed. The sound levels of mining and processing equipment were recorded to identify noise sources. Full-shift worker noise exposures were completed to determine the exposure of various occupations. This paper presents the results of the noise research conducted in both underground and surface limestone mines, detailing the equipment likely to cause worker overexposures, and the occupations experiencing overexposures. Implications for worker noise exposure reduction are also reported.

By Oliver C. Ralston, Dorsey A. Lyon

The data reported in this bulletin are largely the result of experiments conducted by the Salt Lake City station of the Bureau of Mines in cooperation with the department of metallurgical research of the University of Utah. The work on lead is only one of the phases of the investigations carried on at that station during the years 1914 to 1916. The results of similar work with zinc ores and with copper and other ores will be published in future reports of the bureau.

Jan 1, 1918

By Robert F. Randolph, Jeffery L. Kohler, David C. Byrne

Multiple versions of an educational message can reach a diverse population more effectively than a single version. For instance, some workers are trained in formal classrooms while others are self-taught. The National Institute for Occupational Safety and Health has developed multiple versions of a hearing loss simulator (an interactive software package, a Web-based module, and an electronic slide show) to show how a single set of information can be readily adapted to different delivery methods. The three versions of the simulator were developed with a minimum of effort and expense compared to a single, less-flexible version. The interactive software is best for training sessions led by a hearing conservation professional, the Web pages are best suited for an individual worker, and the slide show is best for a small, more-generalized, training class. This paper will describe additional advantages and disadvantages of different delivery systems and will show what considerations are helpful in designing content that can be readily adapted to alternate presentations.

Jan 1, 2002

By M. R. Geer, H. F. Yancey

"INTRODUCTION Throughout the history of coal washing, the jig has been one of the most important coal-cleaning appliances. In 1935 34.7 percent of the 45,361,021 tons of clean coal produced was the product of jigging. 4/ Previous to 1928, most of the jigs used in the United States were of the piston type, with which sufficient mobility to allow stratification in bed is imparted by the reciprocating up-and-down movement of a piston in the water compartment adjacent to the screen compartment. In 1928, the Baum type of jig was introduces in this country and has since come into wide spread use. In this type, water pulsations are imparted by application and release of compressed air to the water compartment. All prior studies of the mechanism of seperating cleared coal from impurity by piston-type jigs. 5/ The same laws of settling, of course, apply to both types, piston or Baum, but the character of the separation with the Baum type may be modified more easily because of the flexibility with which air may be handled, as distinguished from the fixed action of eccentrics commonly used in piston jigs. Since no detailed studies are available to show the performance, that is, the character of the separation between coal and impurity, of the Baum type the Bureau of Mines undertook the investigation recorded in this report."

Jan 1, 1938

By Maurice Deul

This bulletin summarizes the work conducted under the Bureau of Mines methane control research program during the years 1964 to 1979. This research effort was directed toward improving existing methods and developing alternative methods of reducing the explosion hazard during mining. The research was performed in three general areas: (1) basic factors that control the emission of methane into coal mines, (2) methane control during mining, and (3) methane drainage in advance of mining. Topics discussed in this bulletin include the magnitude of the methane problem; the equipment and instruments developed; the geological, chemical and physical parameters that control the movement of methane in coalbeds; the direct method of determining gas content; the estimates of gas content from adsorption data; and methane drainage, through shafts, through horizontal boreholes, through vertical boreholes, or through slant holes. Improvements in ventilation, control of methane in gob areas, and water infusion are also discussed, as is the potential use of coalbed methane as a supplement to natural gas supplies. This bulletin provides a comprehensive source of information on the accomplishments of the Bureau's methane control research program, on the technology developed, and on the direction of further research.

Jan 1, 1986

By R. V. Higgins

The Bureau of Mines investigated the use of electronic computers for obtaining more information about relative permeabilities of reservoir rock to oil and water. It was found that there are many possible combinations of relative permeability curves that will result in virtually the same recovery versus injection) but they require different times and rates to recover the oil even with different mobility ratios. Permeability curves obtained by the use of non-viscous oil and employed for calculating the waterfloods of viscous oils can lead to serious inaccuracies. For viscous oils) the wettability characteristics in the middle portion of the permeability curve affect recovery nearly as much as other portions of the curve; this) however) is not true for non-viscous oils in water-wet reservoir rock.

Jan 1, 1967

By J. Chilton

The fact that methane ignitions continue to occur at the mining face indicates that monitoring with machine-mounted methanometers does not always indicate the presence of high methane concentrations. Methane concentrations at the face change quickly due to changes in airflow. By measuring these changes in airflow, it may be possible to predict changes in face methane levels more quickly. Currently there are no techniques or instruments to accurately measure airflow in by the mouth of the ventilation curtain or tubing. Tests conducted in the NIOSH ventilation test gallery compare the data provided by one-, two-, and three-axis ultrasonic anemometers. The effects of changes in airflow direction and turbulence on instrument readings are discussed, and guidelines are given for selecting the type of instruments to be used for monitoring airflow near the mining face.

By Gerald T. Homce, James C. Cawley

Arc flash generally refers to the dangerous exposure to thermal energy released by an arcing fault on an electrical power system, and in recent years, arc flash hazards have become a prominent safety issue in many industries. This problem however, has not been effectively addressed in the mining industry. MSHA data for the period 1990 through 2001 attributes 836 injuries to “non-contact electric arc burns”, making it the most common cause of electrical injury in mining. This paper presents results from several elements of a recent NIOSH study of arc flash hazards in mining, and provides information and recommendations that can help reduce these injuries. Characteristics of past arc flash injuries in mining are first outlined, such as the electrical components and work activities involved (based on MSHA data). This is followed by a review of important concepts and terminology needed to understand this hazard. Next, methods for identifying, measuring, and managing arc flash hazards on a power system are covered, with emphasis on recommendations found in NFPA 70E, Standard for Electrical Safety in the Workplace. Finally, results are presented from a detailed arc flash hazard analysis performed on a sample mine electrical power system using IEEE 1584-2004a, focusing on components and locations presenting severe hazards as well as engineering solutions for reducing the risk to personnel. Index terms – electrical arcing, electrical burns, mining, arc flash hazard analysis

To mine uraniferous sand-stone in an economically feasible and environmentally compatible manner without placing men underground. Approach Uraniferous sand is remotely extracted through a single borehole by cutting Into the are around the borehole with a high pressure water Jet, and pumping the resulting slurry to the surface. How It Works A 16-inch-diameter borehole Is drilled from the surface down into the burled mineral deposit, and the mining tool Is installed. High pressure water Is released as a jet from a nozzle In the mining tool to erode the are, forming a slurry that flows to the bottom of the cavity. The slurry Is drawn Into Inlets located near the bottom of the drill string. See drawing. After being pumped to the surface, the slurry is weighed, metered, and checked for radioactivity. It is then deposited Into one of a pair of sumps. Water collecting in the sumps drains Into an adjoining pond for reuse. Thickened are In the sumps is removed and placed In piles.

Jan 1, 1978

By Gregory Molinda

NIOSH has recently completed a study of the interaction between polyurethane (PUR) and coal mine roof in order to determine the mechanism of reinforcement, in both highly fractured rock and unfractured rock. Four case studies of PUR rein­forcement are presented. At a West Virginia site, a borehole camera revealed the location of roof voids and guided the PUR injection. By injecting polyure­thane into a zone from 0.6 to 1.8 m (2?6 ft.) high in the roof, a roof beam was created and ongoing intersection falls were halted. In another highly fractured roof in a western Pennsylvania mine, a total of 5.8 cm (2.3 in.) of rubbleized rock was found in a zone up to 3 m (10 ft.) into the roof. Untargeted PUR injection filled approximately 1/2 of the fractures. These two case studies showed that it is not necessary to fill up 100% of the void space to create stability. In the other two field sites, polyurethane was injected into weak, but unfractured roof. Post-injec­tion video monitoring showed that weak bedding planes were hydraulically wedged open and polyure­thane injected along bedding. The reinforcement value of this injection method is limited because of the wafer-thin layer of PUR introduced along bedding, and the lack of a PUR ??webbing?? which would serve as a structural framework to provide strength. It was determined that video inspection prior to PUR injection can aid in identifying the fracture zones to target, and minimize ??blind?? pumping and loss of PUR.

Jan 1, 2008

By Kim M. Cornelius

Musculoskeletal injury is a term used to describe a wide range of soft tissue disorders which affect the nerves, tendons, and muscles. Common examples include lower back pain, tendonitis, and carpal tunnel syndrome. The majority of these injuries are not the result of sudden mishaps, but usually develop gradually from repeated wear and tear. Symptoms may first appear after weeks, months, or even years. Symptoms may result from many types of activities, performed at work or at home, and it is often difficult to attribute a single event. In fact, it is more common to identify the factors which may have contributed to the development of the condition. The terms repetitive strain injuries or cumulative trauma disorders (CTDs) have been commonly used to refer to disorders that have occurred due to work related activities (Putz-Anderson, 1988; Fraser, 1989). Three main risk factors contribute to CTDs: force, repetition, and awkward postures. Any one or combination of these may contribute to the development of CTDs. Therefore, the design of equipment in conjunction with the required tasks should attempt to reduce these risk factors. Examining the layout of the work area to help identify tasks which may contribute to cumulative trauma is necessary. The following list(Putz-Anderson, 1988), describes ergonomic concerns that, overall, should be minimized at the work area:

Jan 1, 1997

Objective To reduce dust generated from soiled floors within enclosed operator cabs. Background Enclosed operator cabs are widely used on mobile excavation equipment in the mining and construction industries. They protect the operator from bad weather, noise, and airborne dusts. The inside cab environment usually must be kept at very low dust concentrations because of quartz dust generated from the excavation of silica-bearing rock. For cabs to be effective in controlling airborne respirable dust, they must have an efficient air filtration system, while providing a positive pressurization of the cab interior. Ideally, the recirculated and exterior makeup air filtration should provide at least 99% capture efficiency for dust particles as small as 0.3-µmaerodynamic diameters. Many of these enclosed cabs use heating units mounted or directed along the floor (see figure 1), which can cause dust entrainment problems. Prior studies by the National Institute for Occupational Safety and Health (NIOSH) of enclosed cabs have shown that these floor heaters can generate notable amounts of dust within the cab enclosure (see Technology News 486). Multiple-shift dust levels measured inside a drill cab increased on average from0.04 mg/m3 during the summer months to 0.68 mg/m3 during the winter months. Additional dust level measurements, made with optical particle counters during a nondrilling time period, verified that dust levels inside the cab increased from 0.03 to 0.26 mg/m3when the floor heater/fan was turned on. Dust levels within the cab also became greater than the ambient air dust levels outside of the cab when the floor heater was turned on during the nondrilling time period. This shows that the floor heater was a notable dust source problem. Cab floors are commonly soiled from operators tracking dirt inside the cab upon entering from the mine or construction site. Interior cab dust levels can be increased by (1) airflow disturbance of the soiled floor or (2) operator disturbance of the soiled floor. Approach During prior NIOSH surveys of surface coal mine drills, several drills with very low cab dust levels (#0.1 mg/m3) were observed to have floor sweeping compound spread out over the cab floor during the working shift. This initial observation led to a more controlled A-B study of the effect of the sweeping compound on the interior cab dust levels. This study involved dust sampling with and without sweeping compound inside the cabs of a bulldozer and two drills. Sweeping compounds commonly use sawdust or cellulose as the main bulk material, with oil or wax added for dust adhesion purposes. Sand is sometimes added to increase bulk density. Sweeping compounds with sand are commonly used to sweep up concrete floors. Those without sand (usually referred to as "gritless") are used to sweep up smooth finished floors. Most of the oils and waxes used for the adhesive ingredient are petroleum-base and can have an irritating odor. People sensitized to petroleum distillates could have allergic reactions to these sweeping compounds. A few companies offer non petroleum-base sweeping compounds, using either a natural oil or chemical additive for dust adhesion. During this study, it was decided that only the gritless sweeping compound (without sand) would be used, eliminating the addition of another potential silica source inside the cab. Since the sweeping compound would be applied on the enclosed cab floor for the duration of the shift, it was decided to use a canola oil-base sweeping compound to eliminate irritating odor from the petroleum-base sweeping compounds. The natural canola oil-base sweeping compound had a slight woody scent. The three pieces of equipment used in this study had notably different cab layouts. The bulldozer had a small cab with vents discharging air-conditioned or heated air from adjustable louvers at operator waist level and floor level. The bulldozer also had a cloth fabric seat and a carpeted floor. Drill A had a large cab with the heat directed from adjustable louvers at operator knee level and the air-conditioned air directed from cabin ceiling louvers. This drill had a vinyl fabric seat and a steel plate floor. Drill B had a small cabin with the heat directed across the floor (see figure 1) and the air-conditioned air directed down from the ceiling. It had a vinyl fabric seat and a worn rubber mat on a steel floor.

May 1, 2001

By D. Harrington

The greatly extended use of the underground trolley-locomotive system for hauling coal without doubt was one of the most important factors in the rapid progress of coal mining and the increased production of coal in American coal mines during the period 1910-20. Much of the superior efficiency of production of our underground coal and metal lines should also be credited to the trolley locomotive system. The trend to mechanization of mines during the past 15 years, mere particularly the past 5 years, with higher production per man employed and greatly accelerated advancement of working places, has required increased use of trolley locomotives, necessitating larger equipment, higher speeds, and more 'frequent turn over of pit cars. This is re¬flected in increased size of locomotives and the use of larger mine ears (some with a capacity up to or over 10 tons); moreover, heavier rails and larger-size trolley wires have boon or ought to have boon installed. Trolley-locomotive haulage has proved to be rapid; economical, efficient, and productive; nevertheless; in spite of these advantages, so-many hazardous features and, unsafe conditions are involved and the price paid in life and property is so high as to justify the statement that the system should be scrapped if it cannot be operated under reasonably safe conditions. Since bare trolloy wires were introduced into underground mines, they have boon responsible for the death of hundreds of diners, property damage totaling millions of dollars, an indeterminate loss of tonnage through the abandonment of mines or parts of mines, and loss of time after disasters caused by fires or explosions originated by the trolley haulage system.

Jan 1, 1945

By Paul C. Hyndman

The U.S. Bureau of Mines investigations of the three subunits (fig. 1) of the Homestead RARE II area (No. 6291) revealed no evidence of mining activity or mineral deposits in the area. The Iron Dyke Mine, 3 mi (5 km) outside the study area produced ore between 1916 and early 1982 from a volcanogenic massive sulfide deposit in the Permian volcaniclastic Hunsaker Creek Formation of the Seven Devils Group. The Hunsaker Creek Formation does not crop out in the RARE II area, but extends into the area beneath Miocene flows of Columbia River Basalt. The abundant basalt in the area could be used as aggregate or dimension stone, but equivalent deposits exist closer to markets. INTRODUCTION Location and Access The Homestead RARE II area (fig. 1) encompasses 6260 net acres (253U ha), in three units, of the Wallowa-Whitman National Forest in Baker and Wallowa Counties, Oregon. Two small units of 160 and 300 acres (65 and 120 ha) are 5 mi (8 km) north and east of the main study area. Homestead, Oregon, on the Snake River, is about 3 mi (4 km) south of the two small areas, and about 3 mi (4 km) northeast of the main study area. Peripheral access is provided by State Highway 86, U.S. Forest Service Road 39, and ancillary roads and trails.

Jan 1, 1983

By Richard Mainiero

In any construction project involving explosives, care must be taken to protect workers from carbon monoxide (CO) generated by blasting operations. CO is an odorless, colorless gas that can cause illness and death by asphyxiation. In general, the first symptoms include headache, fatigue and lightheadedness. At higher exposures to CO, skin flushing, rapid heart rate, and lowered blood pressure occur. At ever, higher exposure levels, decreased attention span is followed by nausea, vomiting, unpaired coordination, fainting, coma, convulsions and, finally, death. The detonation of explosives in blasting operations generates a range of toxic fumes, but CO is the most insidious because it is colorless, odor less, and is long lasting, since it is not readily removed try reaction with ground water, soil or rock. Additionally CO is generated in relatively large quantities compared to other toxic: fumes. CO may continue to seep out of blasted material long after the odor commonly associated with detonated explosives has dissipated. It is never safe to assume as confined space in the vicinity of a blast is clear of toxic fumes. CO may be present even if the area looks Clear and many hours have passed since the last blast.

Jan 1, 2000

By Martin D. Conyac

A mineral resource survey of rock types and geologic structures indicates that the Mt. Henry RARE II area has low potential for the discovery of metallic minerals. Potential for coal and geothermal resources is negligible. Essentially, the Mt. Henry RARE II area has had no claim-staking activity, nor has any mine been developed in it. SETTING Size and Location The 23,000-acre (9,308 ha) "1t. Henry RARE II area (No. 1-666) lies within the Kootenai National Forest approximately 36 mi (58 km) north of Libby, Montana, in the Purcell Mountain; of Lincoln County. Irregularly shaped, the area measures roughly 5-1/2 mi (8.9 km) north-south by 8 mi (12.9 km) Past-west, and lies about 1-1/2 mi (7.2 km) south of the Canadian border.

Jan 1, 1982

By A. H. Shoemaker

This paper describing the mining practices at the Old Dominion mine, Globe, Ariz., is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various minim districts in the United States. The Old Dominion mine is situated in the eastern port of the Globe-Miami district, about 1-1/2 miles north from the center of the town of Globe. An average of nearly: 1,200 tons per day was mined during 1928. The prevent production is about 1,500 tons per day; of this amount,, approximately 100 tons is direct-smelting ore that is shipped to the smelter at Miami and 1,400 tons milling ore which is treated in the company?s concentrator at Globe. About 600 men are employed at the mine.

Jan 1, 1930

By R. P. Vinson, Abdurrahman Cetinbas, Joseph Cervik, M. G. Zabetakis

The effect of water infusion on the flow of methane and on the production of dust was investigated at an active face in the Pittsburgh coalbed. The average total flow of methane at the face decreased by approximately 79 percent, whereas the flow from the ribs increased about 24 percent after infusion. On the day after infusion, dust concentrations appear to have been reduced; however, the presence of large quantities of rock dust obscured the results on the following days.

Jan 1, 1972

By Adam K. Smith

Occupational hearing loss is a permanent illness with no recovery currently possible. For underground coal mine workers, Noise Induced Hearing Loss (NIHL) continues to be a serious health issue. One of the principal and fundamental machines used in underground mining operations is also one of the loudest. Noise generated on the continuous mining machine is the result of 3 operational components: the cutting system, the dust collection system, and the onboard conveying system. During underground acoustic evaluations, the conveyor system noise was observed to be dominant. In order to more closely examine sound generated by the continuous mining machine, sound power levels were measured in a reverberation chamber at the Pittsburgh Research Laboratory (PRL). Different chain types and configurations were installed on the conveyor system, and the resulting sound power level ranged from 118 dB(A) to 108 dB(A). Noise generated by the dust collection system was also examined and found to be 107 dB(A).

Jan 1, 2008

By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining the potential for reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain t did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A bibliography of pertinent literature is included as an appendix. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978