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Prevent the propagation of a fire and control the spread of smoke and toxic gas in underground mines. Approach A fire door suitable for large openings in underground noncoal mines and providing protection for openings requiring 11/2 hours of fire resistance, a 250°F maximum temperature rise, and high pressure differentials was de-signed, laboratory tested, and in-mine tested. How It Works The door is a double-acting swing type. Its two panels. connected by an overhead linkage, open in opposite directions. Consequently, high pressure differentials across the door have little effect on the force required to open and close the door. The door is constructed of 14-gauge sheet steel skins welded to both sides of a 5-inch-wide steel channel frame. The frame is rein-forced with 5-inch-wide steel channels in a horizontal and diagonal pattern. The voids between the reinforcing members are filled with a ceramic fiber insulation material to limit the surface temperature rise of the unexposed side of the door during a fire. A fire -resistant neoprene-coated fabric is used to seal around the edges of the door panels. The door is opened and closed by an air cylinder, attached to the over-head linkage and operated by lanyards on either side of the door. The door design includes an optional airlock manway for drifts of adequate width.

Jan 1, 1983

Provide a low-maintenance, reliable means of generating bubbles and controlling bubble size for column flotation. Approach Commercial sparger systems used in flotation columns to process minerals provide only limited means of controlling the size of bubbles generated and the rate of air injection. Generally, these limitations are a detriment to flotation performance, particularly in recovering coarse or fine mineral particles. In addition, conventional bubble generation systems require frequent maintenance, often requiring shut-down of the column itself for repairs. To permit greater control of the bubble size generated in the flotation column and to eliminate the counter-productive problems associated with the operation of current air sparger systems, the Bureau of Mines investigated alternative methods for generating bubbles. Based on the investigation, an external bubble generation system was designed, developed, and laboratory and commercially tested.

Jan 1, 1987

By A. D. Mah

Thermodynamic data on compounds of arsenic and sulfur were critically evaluated by the Bureau of Mines. Changes of standard enthalpy and Gibbs energy, and logarithms of the equilibrium constants were tabulated as a function of temperature for reactions involving these compounds.

Jan 1, 1982

Prevent collisions between large mine-haulage trucks and smaller vehicles parked in areas not visible to the haulage-truck operator, Approach Two electronic systems were developed to detect the presence of vehicles in the blind areas of a parked haulage truck. The systems can warn haulage truck operators of presence of vehicles that are blocked from view. The systems do not apply for trucks in travel. How It Works The systems use electronic transmitting techniques-one system is based on low-frequency radio waves and the other on very-high-frequency radio waves. Each system requires that a signal transmitter be mounted on the smaller vehicle to be detected. Continuous signals from this transmitter are sensed by receiving antennas mounted on the right front and rear of the large haulage truck. Upon receiving a signal, the receiver energizes warning lights and a buzzer in the cab of the haulage truck, alerting the operator to a possible collision hazard. Detection distance is adjustable, depending upon the size of the haulage truck, but a minimum of 30 feet was the design goal.

Jan 1, 1990

This Information Circular from the National Institute for Occupational Safety and Health (NIOSH) documents and supplements the information presented in a series of workshops held during 2002 and 2003. The primary intended audience consists of all who are involved in developing and conducting miners? training. According to the Mine Safety and Health Administration (MSHA), mine operators reported 240,000 full-time equivalent workers and independent contractors reported 42,000 full-time equivalent workers working on mine property during the year 2000. Unfortunately, these workers have a relatively high risk of suffering serious work-related injuries and illnesses. The mining industry has the highest rate of occupational fatalities among all U.S. industries. The fatality rate is 30 deaths per 100,000 workers compared to 4.6 for all private industry(Morbidity and Mortality Week Report, 2001; NIOSH, 2002).Compared to workers in other industries, miners also have a relatively high rate of nonfatal lost-time injuries, and their injuries tend to be more severe (Bureau of Labor Statistics, 1999). Many miners are also exposed to significant health hazards, including coal and silica dust, diesel exhaust, and noise. More than 1000 U.S. miners die of lung disease each year(NIOSH, 1999).

Jan 1, 2002

Eliminate accidental tramming of a cleanup tractor. Approach A switch was installed in the operator's seat cushion to pre-vent the cleanup tractor from tramming without an operator in the driver's seat. How It Works The operator must be seated, and the Forward/Reverse Switch (that controls tramming direction) must pass through the NEUTRAL position before the vehicle will tram. See Figure 1. A pressure-sensitive seat cushion switch, a solid-state relay, and a double-contact relay were added to the control circuitry of an S & S BMUAT -88 cleanup tractor to create this tramming interlock. The weight of the operator on the cushion closes the seat cushion switch (Figure 2, A). This activates the solid-state relay (B), which completes the initial circuitry. Moving the For- ward/Reverse Switch (C) to NEUTRAL energizes the coil in the double-contact relay (D) and closes both contacts. One contact completes a sustaining circuit which keeps the double-contact relay energized. The second contact transfers power to the remaining contacts within the Forward/ Reverse Switch. These circuits are shown in greater de- tail in Figure 2.

Jan 1, 1978

By A. T. Iannacchione, D. G. Puglio

The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata. Trends established from mapping, including prediction of areas of high methane emissions, were extrapolated to unmined areas. "Wants" in the coalbed are of two types: Erosional and depositional. Erosional features occur where north-south-trending sand-filled channels cut into the coalbed. Variations in depositional environments have caused the coalbed to "split" into several thinner units. Slickensides, commonly indicative of unstable roof, are adjacent to and on the underside of sandstone channels; they were caused by differential compaction and by soft sediment sliding along the contact between the sandstone and adjacent shale. The frequency of unstable roof also increases where the interval between the Middle and Lower Kittanning coalbed is less than 30 feet. The zones of weakness at the contacts above and below the Middle Kittanning coalbed are the controlling factors for unstable roof in these strata. Methane emissions from the coalbed are controlled primarily by depth, fracture permeability, and rank of coal. Local geologic factors are coalbed thickness, associated rock strata, structure, and proximity to outcrop.

Jan 1, 1979

Provide longwall operators with practical information and guidelines concerning mine design to reduce problems associated with the interaction of adjacent workings in multiple-scam longwall mines. Background The high productivity achieved by longwall mining demonstrates its potential to provide a substantial segment of underground coal production. Longwall mines produce more than 30 pct of underground coal, up from pct just 15 years ago. However, the continued growth of this mining method without appropriate multiple-seam planning may increase the cost and risk of mining. Research by the U.S. Bureau of Mines (USBM) indicates that 25 longwall mines (32 pct of the total number in the United States) have mining in adjacent coalbeds either above or below. About half of these longwall mines report some type of interaction problem with the adjacent workings, such as caving due to subsidence. Optimization of mine design factors is the best means for controlling interactions between operations in adjacent scams. To avoid higher mining costs, operators should focus on adopting practices and procedures that prevent and control interactions in multiple scams. The USBM, in an effort to improve longwall mine planning, has been investigating multiple-seam longwall design and development.

Jan 1, 1994

By A. W. Maynard

Simple chemical spot tests for the identification of major alloying elements in aluminum-base alloys are described. The tests are suitable for use by nontechnical personnel working outside a laboratory. Tests for zinc, copper, manganese, and magnesium employ electrographic sampling methods and sample papers. Use of electrographic sampling in a test for magnesium in aluminum is made possible by using glass fiber filter paper. Differentiations between magnesium and magnesium-silicon alloys of aluminum and between aluminum-base and magnesium-base alloys are made by direct chemical solution tests. Description of a device for obtaining reliable electrographic samples is included. A sequence of testing for identification by alloy groups is given.

Jan 1, 1971

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

THIS PROGRAM TRANSFORMS FREE FORHATED BRANCH DATA INTO A FORMAT SUITABLE FOR INPUT TO THE PENNSYLVANIA STATE UNIVERSITY MINE VENTILATION SIMULATOR (PSU/HVS 1. BRANCH RESISTANCES ARE ASSUMED TO HAVE BEEN ALREADY CALCULATED, IIOWEVER THIS PROGRAM CAN BE EASILY MODIFIED TO HANDLE THE ADDITIONAL INPUT DATA REQUIRED FOR RESISTANCE CALCULATIONS IN THE PSU/MVSO THE PROGRAM IS WRITTEN IN FORTRAN IV WITH WATFIV.

Jan 1, 1977

By Timothy J. Orr, Michael J. Beus, Frank T. Duda

The technology to enhance safety and control features for mine shaft hoists is being investigated by researchers at the U.S. Bureau of Mines (USBM). The objective of the research is to prevent injuries and fatalities related to hoist and elevator operations. Monitoring and controlling mine hoisting operations will allow hoist operators, inspectors, and maintenance personnel to increase their awareness of potentially dangerous situations and provide controls for safer operations. Process simulation and visualization software, real-time data sensing, and advanced programming techniques are being applied to this problem. Development of reliable and cost-effective sensors and data acquisition interfaces to monitor hoist loads and detect slack rope conditions is underway. Three-dimensional design software was used to visualize mine hoisting to enhance understanding of hoist operations. Quick Basic and Visual Basic (an object-oriented Windows interface) are being used for acquiring and processing hoisting data. Testing and evaluation of components are underway at USBM testing facilities. The resulting system will allow hoist personnel to assess critical operating parameters, such as hoist position, speed, acceleration, conveyance load, and rope tension.

Establish a procedure for reliably determining cation exchange parameters at an in situ mining site. The Problem Predicting the movement rates of pollutants from waste disposal sites requires reliable measurements of cation exchange parameters since cation exchange can retard pollutant movement. Reliable measurements of these parameters are also required for predicting the length of time needed to restore groundwater quality after in situ mining. Cation exchange is otten the controlling mechanism for the replacement of leach solution cations by the cations in the returning ground-water. Unfortunately, laboratory measurements using core samples are of minimal reliability. The uneven clay distribution at most sites produces a high variability in laboratory results. In addition the flow pattern in the laboratory tests is different from that in the field. Approach Bureau of Mines research has developed a field-test procedure that is quick and yields reliable and representative data. A corresponding data analysis procedure was also established in order to verify the' applicability of the computer simulation model of cation exchange used in the analysis, and of the general analysis procedure, with actual field data.

Jan 1, 1986

By Fred C. Turin, Sean Gallagher, Kim M. Cornelius, William J. Wiehagen

An important part of initiating a site-wide ergonomics evaluation process is prioritizing jobs to be analyzed. While injury data is important, other factors such as worker discomfort and physical exertion requirements, should be considered. This paper describes the use of four sources of data (injury records, the Nordic Standardized Musculoskeletal Questionnaire, supervisor interviews, and management concerns) to prioritize jobs for ergonomic analysis. The approach described integrates the four sources using a decision matrix to prioritize jobs for ergonomics analysis.

By Sarkis G. Ampian

The Bureau of Mines has developed a method for identifying fine particles of beryl in mineral samples by preferentially staining the beryl grains. The sample is first subjected to a heated sodium hydroxide solution to etch the beryl particles, which are subsequently stained an intense blue color in a boiling alkaline solution of quinalizarin. Positive identification of beryl grains permits quantitative analyses by microscopic techniques. INTRODUCTION Beryl, a beryllium aluminum Silicate, is the principal ore mineral of beryllium. The only known commercial concentrations of this mineral are found in pegmatite dikes of granitic composition. Normally beryl is associated with muscovite mica, quartz, and the sodium-and potassium-bearing feldspars (orthoclase, microcline, and albite). Other beryllium-bearing minerals which are found occasionally in minor amounts with beryl are phenacite, a beryllium silicate, and chrysoberyl, a beryllium aluminate.

Jan 1, 1962

By R. Karl Zipf

A method is presented for creating realistic numerical models for practical coal mine ground control. The method includes procedures to collect the necessary mechanical input parameters from a geologic core log, procedures to set up a model, and procedures to interpret calculation results. The input parameters come from a detailed geologic core log and extensive point load tests of estimate rock layer strength. A suite of material property input parameters is proposed that allows the user to go from core log to numerical model inputs. Rock bolt anchorage properties are also linked to the material properties of each geologic layer in the model. Following this procedure leads to very realistic calculations of the rock failure process and rock support system behavior. These calculations in turn enable realistic comparison of the effectiveness of alternative rock support systems.

Jan 5, 2007

Reduce shaft sinking costs and workers exposure to mechanical hazards, drill dust, blast dangers, and fumes. Approach Replace drilling and blasting by using a large, cab-mounted impact breaker suspended from the bottom work deck of the galloway. How It Works The pneumatically actuated impact breaker is positioned by an articulated boom con-trolled from an operators cab. The breaker delivers 2,000 ft-lb blows that fragment the rock at the shaft bottom. Mucking is accomplished by a backhoe bucket on an articulated boom mounted on the cab. See photograph. The mucked material can be removed either by dumping into a previously drilled borehole or by being lifted out in a muck bucket as shown in the drawing. Positioning of the breaker, rotating the cab around its vertical axis, and moving the cab support frame around the perimeter of the shaft are all controlled by one joystick. Separate controls position the mucker boom, which can be swung horizontally through a 180° degree arc towards either side of the cab. Because the cab can be rotated to any position around its vertical axis, and can also be moved in a horizontal circle around the shaft, virtually any position on the bottom of the shaft can be reached by the breaker and mucker.

Jan 1, 1981

By R. F. Abernethy

A chemical method of determining microgram quantities of arsenic in coal was investigated by the Bureau of Mines to supplement a semiquantitative spectrographic method of determining arsenic in coal ash. In accordance with a method recommended by the International Organization for Standardization, 1-gram samples of coal are decomposed by wet oxidation with boiling sulfuric acid (H2S04) and nitric acid (HN03) to remove the organic matter. After heating to fumes of SO3 to remove HN03, the arsenic is separated as arsine by the action of zinc in H2S04 solution. The arsine is absorbed in dilute iodine solution in which the arsenic is determined colorimetrically by the molybdenum-blue reaction. Two modifications of the method for obtaining the arsenic in solution, in addition to the wet oxidation method, give satisfactory results. The modifications are (1) furnace ashing with MgO added to the coal, followed by treatment with H2S04, and (2) extraction of arsenic from the coal by dilute HNO3 without ashing. Float-and sink-tests show that arsenic is associated mainly with mineral matter in the three coals examined. High-temperature ashing tests show that very little arsenic is volatilized from coal ash below 1,000° C, but it is virtually all removed from the ash at 1,300° C.

Jan 1, 1968

Provide an inexpensive, simple means of supporting highly yielding ground In underground mines. Approach The Bureau of Mines developed a high capacity support post made from standard steel pipe which, when using a 60-inch post configuration, has a 45-ton capacity and a yield length of 24 inches. How It Works The post mechanism is a three-piece unit consisting of a top and bottom leg (made from standard steel pipe) and a separate foot bracket. During installation in the mine, the bottom leg is placed on a relatively flat surface on the mine floor and the top leg is placed over it until its flared end contacts an expansion ring attached to the bottom leg. As the roof and floor converge, the flared end of the top leg is forced into the expansion ring, causing the walls of the top leg to be deformed radially and along the axis. The mechanism will yield until the unit bottoms out after about 24 inches of yield.

Jan 1, 1987

By Robert S. Sanford

In April 1948, the Bureau of Mines was requested to evaluate the graphite deposit' known as the Benjamin Franklin and Just mines in Chester County, Pa. After preliminary investigation, it was recommended that the Bureau core-drill, trench, and sample the deposit and make beneficiation tests on the ore. During the first and second World Wars, flake graphite was in short supply, and a number of deposits in the United States were exploited. In 1942, the Defense Plant Corporation, through its lessee, the Benjamin Franklin Graphite Co., purchased 70.263 acres of graphite-bearing land and built a complete mining and milling plant with a capacity of 300 tons of crude ore per 24-hour day at a cost of $426,250 (Plancor No. 1254).

Jan 1, 1949

By Maria I. De Rosa

Table 1 and figure 1 show the number of fires and fire in¬juries that occurred in underground coal mines by state during 1990-1999. Table 1 also shows by state the risk rates, employ¬ees' working hours, lost workdays, and coal production. Over¬all, 87 fires occurred in 12 states. Twenty-seven of those fires caused 34 injuries (the yearly average was 8.7 fires and 3.4 injuries). One fire and one injury involved a contractor. The underground mine fires required 25 mine rescue team interventions and 30 mine/section evacuations followed by 13 mine/section sealing/flooding/CO2/N2, gas injections. The Ewhr value was 1,003 x 106 hr (In = 0.007), the CP value was 4,008 x 106 st (Frr = 0.022), and the LWD value was 208. Virginia had the most fires (15 fires and 7 injuries). Pennsyl¬vania had the most fire injuries (12 fires and 9 injuries), fol¬lowed by Kentucky (12 fires and 6 injuries), and Alabama (12 fires and 4 injuries). Among these states, Alabama had the highest fire risk rate value (Frr = 0.073), whereas Pennsylvania had the highest injury risk rate value (In = 0.016). Table 2, partly illustrated in figure 2, shows by time period the number of fires, fire injuries, risk rates, employees' working hours, lost workdays, and coal production. The number of fires and fire injuries show a decrease followed by an increase during the five time periods (see table 2 and figure 2). This was ac¬companied by a decline in employees' working hours throughout the periods and an overall small decrease in coal production. The In and Frr values follow patterns similar to those shown by the fire and injury values. By comparison, data from Pomroy and Carigiet [1995] show that during 1978-1992 a total of 11 states were involved in 164 underground coal mine fires (yearly average, 10.8) with 43 injuries (yearly average, 2.9) and 27 fatalities (yearly average, 2; however, the 27 deaths occurred during a single fire caused by an overheated air compressor [MSHA 1984]). The CP value was 5,340 x 106 st (yearly average, 356 x 106 st) (Fn = 0.031). Data on employees' working hours and injury risk rates were not available. Tables 3-8 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 3 shows the major variables during 1990-1999. Table 9 shows the number of fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004