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To restore ventilation and prevent the accumulation of explosive or toxic gases by quickly installing substitutes for stoppings blown down by an explosion. Approach Temporarily replace blown down stoppings with a parachute-shaped brattice which can be erected in minutes. How It Works The self-sealing brattice is secured to the roof, ribs and floor by anchoring its nylon edge strip at several points using extensible poles, shads, or available projections such as roof bolts. The air pressure in the entry pops open the chute of lightweight sailcloth, forcing it tightly against floor, roof and rib. See Figure 1. This emergency brattice has been tested at two locations in the Bureau's Experimental Mine at Bruceton, Pennsylvania. In a test last December, one MESA inspector wearing full rescue apparel (including self contained breathing apparatus) installed a self sealing brattice in an entry at the Bruceton Mine. Although he did not have any previous experience with the device, he easily erected it in slightly less than 10 minutes, using two extensible supports (pogo sticks). Research to improve and refine the self-sealing brattice is continuing.

Jan 1, 1977

By E. J. Gleim

In April 1932, the Bureau of Mines published Information Circular 6595, entitled "Data in Reference to Installation of Cables in Shafts and Boreholes", in which were described methods followed in various sections of the United States when electrical circuits are taken into mines by means of cables suspended in shafts and boreholes. In view of the present tendency to extend high-tension cables along entries and passageways from the bottom of the shaft, borehole, or other point of entrance to coal mines rather than over the surface, it is deemed that the various methods of installing such cables deserve careful consideration, particularly in mines in which gas and coal dust contribute to explosion hazards. This is especially true of localities where there is an inclination to restrict the extension of 2,300- and 4,000-volt circuits into the mines. Probably it is feared that accidental contact with the cables of such circuits may result in more serious shock than with lower voltages; also, it is possible that new circuits are regarded merely as explosion hazards additional to those already existing, regardless of the manner in which the new circuits may be installed. It is the firm belief of some engineers that the circuits can be installed so that they will not be damaged by wrecks or roof falls, thereby eliminating the hazard of explosion from this source while at the same time making the chance of accidental contact remote if not impossible. Moreover, some believe that fire hazards from direct-current systems can be reduced by keeping motor-generator sets close to load centers. Thus, although the alternating-current circuits would be lengthened, the size and extent of direct-current circuits would be kept to a minimum.

Jan 1, 1939

By R. A. Pallanch

This paper, which describes the milling practice at the Midvale concentrator, is one of a series being prepared by the Bureau of Mines. The Midvale concentrator, a custom lead-zinc selective flotation plant, is in Salt Lake County, Utah, on a flat site several hundred yards east of the Jordan River and about 200 yards south of the Denver & Rio Grande Western Railroad tracks leading to Bingham Canyon. The site is at an elevation of about 50 feet above the river, the highest available location, thus allowing maximum storage of tailings.

Jan 1, 1931

By Irving Hartmann

The fire end explosion hazard of excessive coal-dust deposits in mines has been recognized for many years, and important measures have been developed for reducing dust formation and to alley loose dust near its source. Nevertheless, in the course of normal mining it has been estimated that 1 to 3 percent (in some thin, friable seams up to 10 percent) of the total coal mined is reduced to dust of through-20-mesh fineness. In highly mechanized, continuous mining operations the production of fines is even greater. Most dust is trapped near its point of origin and removed from the mine, but large quantities are transported by the air current and by haulage into entries, where the greatest proportion settles on the floor and the balance on the rib and roof surfaces. The latter is generally finer in particle size than the floor dust; this, coupled with its more advantageous position for dispersion, makes the rib-roof dust (also to be referred to as overhead dust) a greater potential explosion hazard.

Jan 1, 1954

By Frank E. Cash, Max S. Petersen

"INTRODUCTION Explosives have been used in ever—increasing amounts since gunpowder was invented. For hundreds of years only low explosives of the deflagrating type were used, and they were fired by means of a flame or hot object. Ben¬jamin Franklin first ignited gunpowder from a distance in 1751 by means of an electrostatic spark. Further efforts to develop a satisfactory electrical method to ignite explosives from greater distances were overshadowed by the invention of safety fuse in 1831, as this offered a relatively simple and inexpensive means of firing explosives.The discovery and introduction of high explosives of the detonating type and the invention of the fulmitate of mercury blasting cap about the middle of the nineteenth century provided the needed impetus for inventors to develop means of firing the cap by electricity. The original high-tension igniter, following Benjamin Franklin's experiment in which the detonating compound was ignited by a spark, was discarded in favor of a low-tension igniter, in which the detonating compound was ignited by a heated wire. The past 2 decades have seen considerable improvement in the design and construction of electric detonators to make them safer and more efficient, yet in spite of the improvement it is estimated that less than 50 percent of the explosives used in industry today are ignited or detonated electrically. The trend, however, is toward the use of electric methods. In recent years numerous-mining companies have introduced electric blasting exclusively at their mines as a means of improving safety and efficiency."

Sep 1, 1946

By Oliver C. Ralston, Foster Fraas

"INTRODUCTION The predominant characteristic of powdered mica is the thin -plate shape of the particulars, and the thinner the plates, the more enhanced is this characteristic. Consequently, it is frequently desirable to grade mica according to the thickness of the plates. Concerning the various possible methods for grading mica, very little has been published. There is also no information on the relative quantities of mica per given range of plate thickness. This paper presents a graphical method that shows how these quantities are distributed and how the different methods of grading compare.CUMULATIVE BULK DENSITYBulk density, which is an indirect measure of the plate thickness, was determined in a small cylindrical cup of 3.37 cubic centimeters volume. The mica was placed in the cup under a standard procedure. The densities thus measured checked these determined in a 273 cubic centi¬meter cup with less than a 2 percent error.In calculating cumulative densities it is important to know how they are averaged. In any grading operation the bulk density of a series of fractions is determined. Starting with the lowest density fraction, the cumulative percent under-density can be calculated through the various fractions. It is possible that quantity may be measured by volume or weight and that the averaging may be done by a number of methods. However, experimentally it has been shown that the quantity must be by volume and that the averaging must be arithmetic. This is illustrated in table 1, in which the calculated and actual bulk densities are listed."

Sep 1, 1942

By H. P. Rue

The Bureau of Mines has recently collected two samples of crude oil from wells in the Greasewood Flat, area of northeastern Colorado. Sample 31310 was taken from the Continental Oi1 Co.'s well Briggs No. 1 which came in on September 27,7.931, with a maximum production of 940 barrels per day. Sample 31311 was taken from the Reiter-Foster Oil Co.'s well Ida Johnson No. 1 which came in on August 24, 1931 with a maximum production of approximately 1000 barrels per day. These two samples of crude oil are typical "intermediate base" crude oils according to the classification defined by Smith and Lane. The characteristics of these two samples, as shown by the Hempel analyses, indicate that they are almost identical. They have a very low sulphur content, and the residuum has a low carbon-residue content which would indicate that they are excellent crude oils for refining. Crude oils yielding a residuum which has a carbon-residue content of 4 per cent or less usually make good material for the manufacture of cylinder stocks. The pour points of the samples and the cloud test of the fractions obtained from the vacuum distillation indicate that the Greasewood Flat oil contains considerable wax. The high wax content would cause some difficulty in transmitting this oil through a pipe fine during extreme cold weather.

Jan 1, 1932

By Steven J. Page

The increasing concern for dust control in metal and nonmetal mining prompted the Bureau of Mines to investigate the comparative effectiveness of three wet dust control techniques for face drilling. Previous attempts to achieve effective dust control on face drills with dry collectors have not met with success, the largest problem being sustained effective dust capture at the face. Results show that (1) foam-through-the-drill can provide 95-pct average total dust reduction in gypsum; (2) water mist-through-the-drill can provide approximately 91-pct average total dust reduction and 93-pet average respirable dust reduction in salt; (3) external boom-mounted water sprays can provide approximately 50-pet average dust reduction for both total and respirable dust in salt. The investigation showed that (1) foam and water in small quantities are very effective dust control techniques for face drills when applied through the drill steel at the point of dust generation, and (2) boom-mounted water sprays are only minimally effective for dust control on face drills.

Jan 1, 1981

By E. F. Ferrell

Gold was recovered from scrap electronic 60-40 (tin-lead) solders by drossing with aluminum or zinc at elevated temperatures. The gold, together with other metallic impurities, collected in the dross phase which could then be separated from the molten solder by skimming or filtering. Drossing upgraded the gold concentration by a factor of 10. Further upgrading was achieved by a combination of steps including an oxidation roast and either a combined cyanidation-amalgamation treatment or an aqua regia leach. The gold was then recovered in highly concentrated form from the aqua regia or cyanide solutions by cementation and from the amalgam by volatilization or dissolution of the mercury. The solder was purified by reaction with NaOH to remove dissolved aluminum or with SnCl2 to remove dissolved zinc.

Jan 1, 1976

By T. Bieniawski

"INTRODUCTION The Congress theme ""Improvement of Mine Productivity and Overall Economics by Modern Technology"" is probably beat: addressed by the subtheme allocated to this Plenary Session. It is appropriate that .Theme 1 emphasizes the simple point that effective use of geotechnical information is the key to improving mine productivity. In essence, this means that: (1) geological and geomechanics, (rock mechanics) data must be collected in sufficient quantity and of high quality; (ii) data interpretation must be performed specifically for purposes of engineering design; (iii) innovative design approaches should be used to bring about Improvements in productivity and safety.While, each of these three aspects .may: seem obvious to any mining engineer it is a fact that the above sequence is seldom followed and as a result, mining engineering not infrequently lags, behind other branches of engineering when it comes to design creativity, efficiency and safety.. . After all, mining is still-one of the most hazardous occupations and we are gathered here to discuss, at the highest world professional forum, how to use more effectively the modern technology. This however, does not mean that mining engineers are less capable than other engineers or that their achievements are any lesser; far from it! Mining engineers are the cream of the engineering society on whose efforts depends the welfare of mankind. Moreover, they have produced minerals and coal evergrowing quantities against evergrowing difficulties. Yet, we must and can become even better because we are not making full use of the modern technology and rock mechanics knowledge already at our disposal, and. we are not being innovative enough to the full extent of .our capabilities."

Jan 1, 1989

By Edward D. Thimons

A remote-actuated stench gas fire-warning system has been designed and tested by the Bureau of Mines. This system makes use of the hard-wire network for the mine's phone pager system, thus greatly reducing the system cost. By locating stench gas canisters with remote-actuation release capabilities near working sections, the fire-warning time can be greatly reduced. In a test of the system in a Missouri lead mine, the time required to warn miners of a fire at two working faces was reduced from about 20min with the conventional system to less than 4 min with the remote-actuated system.

Jan 1, 1984

By L. H. Johnson

"INTRODUCTION The Pennsylvania anthracite industry produced 53 million net tons of anthracite during 1945. Fifty-one million tons was prepared for the commercial market (3), 3/ and 2 million tons (consisting of fine sizes) was used for colliery power consumption. Of the number of tons prepared for market, 17 million tons (33 1/3 percent) was prepared by the use of acid mine water treated with lime.Mine water from underground workings is pumped, drained, and stored in huge quantities. The mine-drainage systems in the anthracite region handle over 200 billion gallons of water annually, of which 150 billion gallons is pumped to the surface. More than 69 billion gallons of water is impounded in underground pools (1). Much of this water is employed for breaker use, dust-control installations; hydraulic backfilling, combatting mine fires; and aiding in the transportation of anthracite in gently dipping places where sheet iron is used Roos(4) estimates that 1,100 gallons of mine water is utilized in the preparation of anthracite mined."

Nov 1, 1946

By M. J. Reasor, M. DiMatteo, J. M. Antonini, K. Van Dyke, Z. Ye

"The inhalation of silica has been shown to produce a dramatic inflammatory and toxic response within the lungs of humans and laboratory animals. A variety of cellular and biochemical parameters are used to assess the silica-induced lung injury. The purpose of this paper is to introduce the use of luminok:Jependent chemiluminescence as a new method to study inflammation in both phagocytic cells and lung tissue recovered from silicaexposed animals. Chemiluminescence, or the emission of light, accompanies the release of reactive forms of oxygen when phagocytic cells are challenged. In this study, male Fischer 344 rats were intratracheally instilled with either silica (10 mg/100 g bw) or saline vehicle. One day after the instillations. a marked increase in the chemiluminescence was observed in the lung tissue and bronchoalveolar lavage cells recovered from the silica- treated animals when compared with the saline controls. The light reaction was markedly decreased by either superoxide dismutase or N-nitro-Larginine methyl ester hydrochloride. Superoxide dismutase is involved in the enzymatic breakdown of superoxide anion. while N-nitro-L-arginine methyl ester hydrocholoride, a nitric oxide synthase inhibitor, prevents the formation of nitric oxide. When superoxide anion and nitric oxide react. they form the highly oxidizing substance peroxynitrite. This study then implicates peroxynitrite as an agent that may be responsible for some of the oxidant lung injury that is associated with silica exposure. The use of luminol-dependent chemiluminescence may prove valuable as a method to measure the earliest events in the inflammatory process. and may be an adjunct in studying the mechanisms that produce inflammation. - Environ Health Perspect 102(Suppl 10):37-42 (1994) IntroductionResearch on inflammation has not produced a method that links the initial events of the process to the controlling events. Rather, a variety of parameters are measured that are the result of and not the basis of the inflammatory reaction. Parameters such as tissue weight, edema, blood flow, enzyme and protein release, or production of metabolites (prostaglandins, leukotrienes) have been used extensively. A method is needed that could be applied to cells of a particular type, groups of cells of different types, and even tissue, in an attempt to study the kinetics of the inflammation as well as being sensitive enough to monitor the early events of the process . Since inflammation is so complicated, the relationship between the control of the initial events and the oxidation process has never been explained nor studied in any derail."

Dec 1, 1995

By Dean H. Ambrose

This Bureau of Mines publication summarizes the status of mine electrical equipment reliability research. Failure rate data were estimated from theoretical, laboratory, and field studies. Tables are presented listing reliability characteristics of molded-case circuit breakers, undervoltage relays, ground check monitors, cables, motors, and control circuitry. Application of failure rate data is shown in tables listing maintenance scheduling intervals of components and components that are most sensitive to the probability of hazardous voltages on power distribution systems in the mines. Complete, accurate, and appropriate failure rates on mine equipment are of the utmost importance for reliability evaluations.

Jan 1, 1985

By Robert D. Schmidt

This Bureau of Mines report describes the development and application of a computer model for simulating the hydrological activity associated with in situ leaching. The model is intended to provide uranium resource developers with a description of the flow behavior of leachants and ground water during the development, production, and restoration phases of a leaching operation involving an arbitrary pattern of injection and recovery wells. Different aquifer environments are modeled, using a closed-form solution to the partial differential equation that describes three-dimensional changes in piezometric head as a result of pumping from leachant injection and recovery wells. The computer program can model a maximum of, 50 arbitarily located wells. Numerical techniques involving difference quotients and Taylor expansions about time points are used to derive time, velocity, areal sweep, and fluid volume parameters associated with leaching hydraulics. These parameters are output by the program in graphic and tabular formats. Other numeric methods insure that the program running time is minimized without significantly affect-ing the accuracy of results.

Jan 1, 1980

By M. A. Schellhardt

"INTRODUCTION The augmented demands for natural gas in many parts of the United States as a result of war have increased the need for information regarding the producing characteristics of natural-gas and gas-condensate-type wells capable of delivering large volumes of gas, as such information is important to the formulation of conservative and efficient operative and recovery practices.,For many years, the capacity of natural-gas wells to produce gas has received studied consideration by Bureau of Mines' engineers, and three reports 3/ on gaging gas-well capacities have been published. In Report of Investigations 2929, Pierce and Rawlins point out that for accurate gaging, the actual pressures at the face of the sand in the well and the relationship between such pressures and the rates of flow of gas through the sand must be determined. Their report describes a method of attacking the problem of determining the actual pressures at the sand by means of observations of pressures and volumes at the wellhead.In Report of Investigations 2930, Pierce and Rawlins explain how the fundamental relation"

Aug 1, 1944

By Clyde M. Pearce

The Lake Superior iron-mining district includes parts of the States of Michigan, Minnesota, and Wisconsin. The laws of each State provide for an industrial commission and for inspection of mines. The following extract from the General Orders on Mines, effective October 25, 1937, issued by the Industrial Commission of Wisconsin, is the only reference to the use of safety catches on mine cages or skips found in the laws and regulations in the Lake Superior iron-mining district: Order 316 - Cages for Hoisting Men. (c) Sides, Gates, and Safety Catches. ***Every cage shall be provided with safety catches of sufficient strength to hold the cage with its maximum load at any point in the event the hoisting cable should break. (d) Testing Safety Catches. The safety catches of cages and skips used to hoist men shall be kept well oiled and in good working order. They shall be tested at least once each month by tying up the cage or skip with hemp rope, lowering a few feet of hoisting cable on top of cage, then cutting the hemp rope, provided that any other system of testing, which is equally effective, may be used.

Jan 1, 1945

By Frank J. Susko

The U.S. Bureau of Mines has developed a computer model to describe a flotation process. Coal data from conventional flotation has been converted to a simple, two-parameter kinetic model developed by Reuter and van Deventer (1,2)3. Each set of coal data was represented by two constants, a and ß, and an average flotation rate. The success of the model was demonstrated when the calculated and experimental recoveries showed good correlation. The two-parameter model allows complex data to be defined much more efficiently than traditional knowledge-based models.

Jan 1, 2010

By M. R. Geer

The ever-increasing need to guard against stream pollution has intensified interest in the problems of handling and disposing of flotation tailing. Therefore, the Bureau of Mines investigated the possibility of using crushed washery refuse to adsorb the free water in thickened flotation tailings on a bench scale and then in a pilot plant because the conventional methods of disposing of coal flotation tailings--impounding them or filtering them so they are dry enough to be conveyed to the refuse dump--are sometimes either impractical because of space limitations or costly because of low filter capacity. Most of the refuse samples tested were of similar mineralogical composition and exhibited similar water retention capability. The amount of crushed refuse required to adsorb the water in a particular tailing was influenced greatly by the fineness of the solids in the tailing and hence the percentage of solids to which it could be thickened. The ratio of crushed refuse to tailing solids required to provide a mixture dry enough to be carried on an inclined conveyor belt varied from 2.4 to 6.4. Several chemical agents that were tested were very effective in turning the free water in tailings into a stable gel. Fly ash also was very effective in adsorbing water.

Jan 1, 1968

By Fred N. Kissell

A self-sealing brattice intended for use during coal mine rescue and recovery operations has been designed and tested by the Bureau of Mines. The major design difference between self-sealing and conventional brattice is that the fabric is cut and sewn BS a hemisphere instead of as a flat sheet. This new type of brattice offers reduced weight, leakage, and installation time. Preliminary testing indicates that the concept is worthwhile, but that further developmental research is required.

Jan 1, 1976