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By Michael G. Zabetakis

Investigation of gas explosions usually reveals that the combustible gases have come from transmission and storage facilities or from natural gas or oil wells. However, combustible gases such as methane and hydrogen can derive from biological processes. Hazardous situations have been created in the past by the use of abandoned mines for the disposal of sewage and rainwater, by the interconnection of storm and sanitary sewers, by sealing the openings in manhole covers when repaving the roadway over a sanitary sewer, and by the construction of buildings over or near garbage fill areas without adequately providing for the release of combustible gases.

Jan 1, 1962

By R. V. Ramani

"The importance of adequate mine ventilation for good health and safety conditions has been recognized since miners first ventured underground. All over the world, governmental actions on mine health and safety arc directly connected with mine atmospheric environments their assessment and control. These governmental actions have been, and continue to be, motivated by the repeated experience that potential threats from inadequate control can evolve, either suddenly or in the long-term, into unpleasant reality, with catastrophic health and safety consequences. These governmental actions arc also an indication of the remarkable professional progress being made in the field of mine ventilation.Surely, no developed country allows underground mines to operate without strong measures for the control of ventilation under legislation specific to the mining industry. In the United States, the federal government's responsibility for mine safety has evolved over the years through a series of legislative actions beginning in 1865 and continuing through 1910, 1941, 1947 and 1952.The passage of the Federal Metal and Nonmetallic Mine Safety Act of 1966 (the 1966 Metal Act), the Federal Coal Mine Health and Safety Act of 1969 (the 1969 Coal Act) and the Federal Mine Safety and Health Amendments Act of 1977 (the 1977 Mine Act) arc the most important milestones in this long legislative history. The 1977 Mine Act adopted many of the stronger features of the Occupational Health and Safety Act of 1970, perhaps the most significant piece of legislation on workers' occupational health and safety in US history.It is worthwhile to ask, ""How far has the United States come in mine ventilation since the enactment of the 1969 Coal Mine Health and Safety Act?"" This Act and its associated regulations defined in great specificity many standards for healthful and safe operation of a mine and. in some cases, what constitutes good ventilation practice."

Nov 1, 1995

By W. C. Hudson

"The Miami-West Palm Beach belt of silica sand, which may be suitable for the manufacture of high-grade glass, extends 65 miles northward from the neighborhood of Miami to the vicinity of West Palm Beach, The sand presumably originated in the host rocks constituting the oceanward slope of the Appalachian Mountains and the Piedmont Plateau of Georgia and the Carolinas. The sand now lies in a long, narrow, and probably thin belt that forms a dune-capped terrace marking a previous stage of submergence. The highest dune crests appear to be no more than 30 feet above sea level, and the water table is about 10 or 15 feet below the general level of the terrace.The width of the belt in several places is known to be more than a mile, and the thickness of the clean glass sand sampled ranged from 4 to more than 7 feet. Visual inspection and the meager data indicate the existence of bodies of glass sand large enough to supply foreseeable markets.Analyses of three samples indicate that beneficiation would make the sand suitable for the better grades of ordinary and flint glass.The prospective grade and quantity of sand, an available market in Florida for glassware, and the expectation of postwar expansion of the new industry of glass producing justify more detailed exploratory work and beneficiation testing.U. S. Route No. 1, Old Dixie Highway, the Seaboard Railway, and the Florida East Coast Railway, all substantially parallel and usually within a width of a mile or two, run along parts of the belt or between it and the coast. In addition to many streets and unpaved roads, a paved road crosses the belt at right angles about every 5 miles. Numerous towns are situated within or near the belt. Any area selected for a mining, processing, and manufacturing plant would be near a railroad, a highway, and water and also accessible to public utilities.The subtropical climate, famous for its pleasantly warm winters, would preclude seasonal interruption of plant operations."

Apr 1, 1946

By B. R. Mohal, F. F. Aplan, S. Chander

"The wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5] and to control the flotation, flocculation, filtration and flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series contains a linear hydrocarbon chain containing nine carbon atoms ( CH3 ( CH2 ) 8-C6H4-( OC2H4 )""' where n is the number of ethoxy groups). The octyl phenol series contains a branched hydrocarbon chain containing eight carbon atoms ( ( CH3 ) 3CCH2C ( CH3 ) 2-C6H4-( OC2H4)"").Initial wetting rates - modified Walker techniqueWalker et al. [ 6] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determined. This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7] to determine the effect of surfactants on wettability of cotton fibers."

Jan 1, 1989

By D. R. Brooks

The Bureau of Mines has tested a dewatering technique for phosphatic clay waste. The technique utilizes a flocculant, polyethylene oxide (PEO), that forms strong, stable flocs that can be dewatered on a static screen followed by further dewatering on a rotary screen or trommel. In field tests conducted in central Florida, clay wastes containing approximately 4 pct solids have been consolidated to greater than 20 pct solids. The rate at which PEO-treated material continues to dewater in a mine cut also was monitored. Preliminary results indicate that PEO-treated material will dewater to 30 pct solids in 80 days. Pretreatment of phosphatic clay waste with lime lowers the PEO dosage required for dewatering.

Jan 1, 1986

By Webster S. Anderson

The design, development, and testing of hydraulic props to provide a lightweight, high strength, recoverable unit is described. Modifications in design incorporating threaded components resulted in the development of a lightweight hydraulic prop fabricated from aluminum alloy tubing. This new design facilitates interchange and replacement of component parts, and the physical properties of the material are not changed as they are when welding is required. The new prop is 65,000 pounds and has a maximum load capacity of a lower weight-to-load capacity ratio than the hydraulic props now available.

Jan 1, 1967

By Frank D. Lamb, D. A. Woodard

"INTRODUCTION The iron-ore deposits near Cranberry, N. C., were worked as early as 1820, and records show that to date at least 1,500,000 tons of ore has been mined.. The early operators depended on selective mining and hand cobbing to yield a product containing 40 to 50 percent iron. Later, a magnetic concentrator was erected by the Cranberry Furnace Co. and was operated periodically until 1930. The magnetic cobbing method employed yielded satisfactory concentrates, but the plant was shut down because costs were too high. 4/Early in 1944, in connection with the sponge-iron program of the Bureau of Mines, North Carolina and Tennessee were surveyed for the purpose of finding a readily available source of high-grade iron ore for use in the experimental production of sponge iron at Salisbury, N. C., and samples from various sources were tested in the laboratory. The Cranberry ore proved to be best with respect to grade of magnetite concentrates produced, and it was decided that a pilot mill should be built on the Cranberry mine property and that the concentrate made there should be shipped to Salisbury for direct-reduction tests in a commercial brick kiln."

Dec 1, 1946

By G. S. Baur, J. W. Montoya, S. R. Wilson

Beryllium occurs in the Honeycomb Hills area in volcanic tuff similar to the more extensive berylliferous tuff occurring 20 miles east at Spor Mountain , Juab County , Utah . Samples from the two areas have been mineralogically examined to ascertain whether they have similar characteristics . The Honeycomb Hills samples showed the presence of beta- Be ( OH ) 2 , as well as an amorphous berylliferous substance , whereas in the Spor Mountain tuff the beryllium- bearing minerals are hydrated bertrandite and berylliferous saponite .

Jan 1, 1964

By Stephen P. Holt, John A. Bowsher

A preliminary examination of the mica deposits in Culberson and Hudspeth Counties , Texas , was made in September 1942 by A. B. Needham, district engineer of the Bureau of Mines . The deposits were reexamined by R. C. Redfield , associate mining engineer of the Bureau in November 1942, at which time he was accompanied by Philip S. Hoyt , geologist , and J. C. Moore , foreman of the Texas Mica and Feldspar Company . Exploratory work was started on February 16 , 1944 , and terminated on April 30 , 1944. A crew of 4 to 10 men was employed under the supervision of the authors .

Feb 1, 1947

By Lincoln A. Stewart

"INTRODUCTION The First Supplemental National Defense Appropriation Act, approved August, 25,, 1941, authorized the Bureau of Mines to investigate sources of raw, material for western production and appropriated funds for that purpose. Numerous iron deposits and prospects in the Western States were investigated. Among those selected for more detailed investigation were tile Apache and Chodiski deposits in Arizona.The United States Geological Survey had examined these deposits in 1929 3/ and estimated that ""the quantity of minable ore reasonably to be expected in this locality will reach 10,000,000 long tons, but it will require prospecting by core drill to demonstrate this quantity with certainty"". C. H. Johnson, a mining engineer of the Bureau of Mines, made a preliminary examination in October 1941 and proposed exploration of the Apache deposit Canyon Creek.A trench sampling project was set up, and work at the Apache deposit commenced in November 1941. Mapping, trenching, and sampling of outcrops was completed in March 1942. Trenches were laid out at approximately 200-foot intervals for about 9,200 feet along the iron outcrop east of Canyon Creek, and channel samples were taken across the iron formation. The outcrop also was explored by trenching and sampling along a 1,900-foot outcrop on the west side of Canyon Creek.The first diamond-drilling campaign at Apache was initiated in May 1942 and continued to January 1943, when work was suspended owing to depletion of funds. Six holes spaced at approximately 500-foot intervals and, 500 feet back from the outcrop on the east side of Canyon Creek were drilled through the iron formation during this period.While this drilling was in progress, the Chediski deposit was mapped, trenched, and sampled. The trenches were spaced at intervals of approximately 800 feet along 10,000 feet of the iron-ore outcrop."

Jul 1, 1947

By Raja V. Rarnani, Robert L. Frantz

"The more than 75 research projects funded throughout the first 10 years of the Dust Center's operation have resulted in numerous cumulative findings fulfilling the goals of the Center. These project descriptions present the methodologies and project-to-project relationships leading to their various accomplishments and demonstrate the mesh between project objectives and Center goals.To develop equipment for collecting respirable dust samples.To develop experimental methods for particle-by-particle characterization of morphology, size, and chemistry.To develop experimental methods for overall respirable dust sample characterization of size distribution, chemistry, and crystallography.The project directly addresses the Center's goals to enhance the understanding of the scientific and engineering characteristics of fine and respirable mineral particles found in mining and milling atmospheres and to establish the relationship between natural and cultural factors (mine geology, mineralogy, mining and milling methods, equipment, and control measures) in the generation of fine particles. The project also aims to contribute to the development of control mechanisms for reducing ambient respirable dust concentrations and worker exposures.The work on this project is related to similar work on Coal Mine Dust Characterization (Project No. 2701/MN1) and Characterization of Dust Particles (Project No. 4203/PS3).Airborne dust sampling was performed at the following locations: 1) a sand and gravel quarry in Southern New Hampshire, 2) a welding facility, 3) a ceramic powder facility, 4) a metal powder facility, and 5) the air in Cambridge, Massachusetts. A portable sampling box incorporating two Sierra personal cascade impactors was designed and produced. At a 2-LPM flow rate, the effective cut-off diameters of the Sierra impactors were 10.0, 6.0, 3.5, 2.0, 0.9, and 0.5 mm, respectively, for each stage, and the air passed through a PVC filter after the last stage. In addition, the sampling box contained a total respirable dust filter. The substrates were weighed carefully before and after collection, and the weight increases were recorded. All films, foils, and filters were put in the balance chamber for more than 8 hours to stabilize the temperature and humidity before weighing. A Cash 21 microbalance (±0.001 mg) was used to weigh the Mylar films, SS films, and filters."

Jan 1, 1995

By A. L. Service

Idaho has nearly 6 billion tons of potential sources of phosphorite, 10 to 31 percent P2O5' above and within 100 feet below entry level, the largest potential of any State in the United States. In 1963 Idaho ranked third after Florida and Tennessee in total mine and marketable production of phosphate rock; Montana ranked fourth. This report describes phosphate deposits, mines, and prospects in 10 districts covering most of the Idaho phosphate field. All mine production of phosphate rock in Idaho comes from surface mines and is processed to phosphate fertilizers, phosphoric acid, and elemental phosphorus. Producing districts are Fort Hall (Gay mine), Trail Creek (Conda and Ballard mines), and Crow Creek (Georgetown Canyon mine). FMC Corp. and J. R. Simplot Co. at Pocatello have the largest elemental phosphorus and fertilizer production facilities, respectively, in the State, followed by Monsanto Co. and El Paso Natural Gas Products Co. (formerly Central Farmers Fertilizer Co.). The only other major phosphate processing plant in the State is the phosphoric acid and phosphate fertilizer complex at Kellogg operated by the Bunker Hill Co. In 1963 a plant was constructed and put on line at Monsanto, Idaho, to recover vanadium from ferrophosphorus produced by electric furnace operations in the area. El Paso Natural Gas Products Co. completed construction of a fertilizer and phosphoric acid plant near Conda in 1965. There is a small fertilizer plant producing phosphate fertilizers for local consumption in Soda Springs.

Jan 1, 1966

By A. C. Fieldner, SIDNEY GOTTLIEB

This report summarizes the research and technologic work of the Bureau of Mines on coal and coal products from July 1, 1947, to July 1, 1948. It is the thirteenth of a series presenting resumes based largely upon publications issued during the year . In some instances , research and testing results , not otherwise available in published form , are presented . The individual publications given as footnote references herein will provide further detail to the interested reader . The period covered by this report was marked by an ever -mounting concern for the adequacy of the Nation's fuel resources and for fuel shortages arising from an increasing demand for fuels at home and abroad . Several reports appeared which delineated the place of synthetic liquid fuels in the future fuel technology and economy of the Nation , emphasized the fact that eventually the principal raw material for the production of such fuels will bet,5,6 coal, and described the progress made by the Bureau of Mines in developing processes for the production of synthetic liquid fuels . heard testimony along similar lines . Increased awareness of the fuels problems confronting the Nation led to an authorization by the 80th Congress for the erection of an anthracite research laboratory at Schuylkill Haven , Pa . , to house expanded Bureau of Mines research on anthracite . Design of the structure was well under way by the end of the fiscal year . ( See fig . 1. ) Looking forward to expansion of Bureau research on lignite , the 80th Congress heard testimony on the problems and programs of lignite research10, 11 as a prelude to authorizing the construction of a lignite research laboratory in North Dakota .

Aug 1, 1949

By V. Castranova, T-M. Ong, V. Vallyathan, M. J. Keane, W. E. Wallace Jr.

"Inhalation of certain forms of silica, asbestos and some other respirable dusts can result in pulmonary fibrosis, characterized by destruction of the surfaces of alveoli and respiratory bronchioles. Fibrous thickening of the alveolar septa decreases the lung's capacity for gas exchange.Pulmonary macrophage damage by respired dust may initiate the fibrotic response.In one proposed mechanism, dust particles interact with the plasma membrane of a macrophage. This damages the cell or induces some hyperactivity of the cell, resulting in excessive release of lysosomal enzymes and reactive forms of oxygen (1). These reactive enzymes or radicals then damage the alveolar surface epithelial cells. A second mechanism has also been pro¬posed (2,3) in which dust damage to the macrophage causes the release of mediator substances which induce pulmonary fibroblast cell proliferation and increased collagen synthesis. This produces fibrous tissue in the terminal air spaces (4,5).Mineral surface interactions with plasma membrane lipoproteins have been proposed as a mechanism of lytic damage of pulmonary cells by silica dust in numerous models (6,7). The significance of dust surface proper¬ties has been further revealed in studies showing significant changes in dust induced cytotoxicity as a function of dust surface crystallinity and organic or inorganic contamination or coating of mineral surfaces (8,9). Such modification of the mineral surface might interfere with surface sites responsible for the toxicity of dusts for pulmonary macrophages, thus interrupting the early stages of the process of fibrosis.In vitro cellular assay systems using erythrocyte hemolysis or the release of macrophage cytosolic or lysosomal enzymes following dust challenge, have been used to analyze the initial mechanism of dust damage to cells. However the ability of these assays to predict the pulmonary disease producing potential of various dusts is imperfect owing to some ""false positive"" results. These assays as performed are therefore questionable models for the initial lesion in pneumoconiosis or silicosis. In particular, kaolin frequently is found to have comparable biological activity to silica quartz in these assays (10,11).Silica and kaolin have distinctly different fibrogenic potentials. Silica is highly fibrogenic, resulting in both acute and chronic silicosis (12). Some epidemiological data and animal experimentation data have indicated that long term exposure to kaolin can result in pneumoconiosis; however, kaolin is relatively benign as compared to silica (13-18). Kaolin is also of interest because it is one of the major mineral inclusions in Eastern U.S. bituminous coals. We have observed that exposing respirable sized native silica or kaolin for two hours to pulmonary macrophages results in a greater enzyme release for kaolin exposures, on a dust mass basis. Exposure of erythrocytes to the dusts also results in greater levels of hemolysis by kaolin for equal mass respirable dust doses. Therefore, these results do not correlate positively with known disease inducing potentials of the two dusts.Characterization of physical and chemical surface properties of dusts involved in occupational exposures, and characterization of the alteration of those surface properties which are likely to occur upon deposition of the dust in the lung, should improve the identification of respiratory disease hazards.Inhaled dust particles deposited in the lower respiratory tract will come in contact with pulmonary surfactant. This surfactant forms a surface film on and emulsion in the liquid hypophase coating of the alveoli and respiratory bronchioles. The primary constituent of this pulmonary surfactant is the lipid diacyl glycerophosphorylcholine, lecithin (19). Because this lipid is also a major component of cell membranes, it is possible that surfactant can interact with mineral dust to alter its Interaction with macrophages and other pulmonary cells and, thus, it"

Jan 1, 1988

By H. Polat, Q. Hu, M. Polat, S. Chander

"The electrostatic charge on spray droplets of ionic surfactant solutions and coal particles was measured and the results were correlated with the dust collection efficiency. When various surfactant were added, the magnitude of the droplet charge increased significantly and it was observed to be a function of surfactant type and concentration. The concentration of maximum droplet charge coincided with surfactant concentration where maximum collection efficiency was observed for these surfactants. Particles of coal also carried substantial amount of charge magnitude of which seemed to be a function of coal rank.Based on the results presented in this paper, it was concluded that ionic surfactant primarily act as a strong electrostatic charge inducer for droplets. Due to interactions between these highly charged droplets and naturally charged particles, the efficiency of droplet-particle collisions play a primary role when compared to the wetting and engulfment phenomenon which could only follow a successful collision. INTRODUCTIONWater spray are widely used to suppress airborne dust in mine atmospheres (Walton and Woolcock, 1960; Kobrick, 1970; Hamilton, 1974; Jayaraman et al., 1986). Several investigators have considered the use of surfactants to enhance the effectiveness of water sprays especially for difficult to wet particles such as those of coal (Glanville and Wightman, 1979). The capture of dust particles by water droplets involves droplet-particle collisions, adhesion of particles to droplets, and engulfment of particles into droplets. Surfactants affect these sub processes through their influence on droplet charge, surface tension, and wetting. The last two mechanism have been thoroughly studied in recent years (Walker et al., 1952; Cohen and Rosen, 1981; Glenville and Haley, 1982; Chander et al., 1988; 1991). However, little attention has been paid to the role of electrical charge on particles and droplets on the collision and adhesion of spray droplets and dust particles."

Nov 1, 1995

By E. Divers

This Bureau of Mines report presents results of an underground evaluation to determine the respirable dust and gas control effectiveness of a combined (push-pull) face ventilation system for coal mines. The system utilizes both blowing and exhaust curtain, continuous miners equipped with radio remote control, and flight conveyors. Bureau of Mines tests showed a 97% reduction in respirable dust concentrations from the usual cab position on the continuous miner to the remote control operator's position. This allowed the remote control operator to be well within, and the usual cab position to exceed, Federal respirable dust standards. Tests utilizing a safe tracer gas, sulfur hexafluoride (SF6), to determine the face ventilation effectiveness of the combined blowing and exhaust system showed that the system also has excellent methane dispersion capability. Where wide entries permit, this combined face ventilation system and use of remote control can be a very effective method for dust and gas control.

Jan 1, 1982

By C. A. Komar

Renewed interest in the underground gasification of coal evolves from comprehensive studies of earth fracture systems that indicate that the movement of fluids can be controlled in the coalbed. In particular, directional property studies of natural microfissure occurrence, permeability, ultrasonic velocity, tensile strength, and orientation of intervals of inherent rock weakness, together with geologic structure setting and fracture trace analysis, can predict the gaseous flow paths in the coalbed. Having this information, the dominant direction in which gases generated and/or liberated by heat would move can be determined so that appropriate well patterns can be developed. Together with advances made in drilling technology that permit long horizontal holes to be drilled through the coal seams, tests can be conducted to determine whether directional control will permit devolatilization of the coalbed and gasification of the remaining hot coke in a systematic manner to produce a low-Btu gas suited for the generation of electricity.

Jan 1, 1973

By Jeffrey H. Welsh

The Bureau of Mines studied the use of computerized, continuous, remote monitoring systems for safety from power system faults in underground coal mines. In this report the need to improve protection against power system faults is documented, and types of faults are identified. The relationship between mine safety regulations and computerized, continuous, remote monitoring is analyzed.

Jan 1, 1983

By C. H. Larsen

A 9-month study of the uses of wire rope associated with U. S. underground coal mining is reported. Rope applications are broken down into hoisting and nonhoisting applications where "hoisting" refers to transport in vertical and inclined shafts. The former receives the greatest emphasis since it represents the most critical rope application from the stand-point of production and safety. The discussion of hoisting practice includes aspects related to the mine operators as well as those related to the equipment builders and wire rope manufacturers. U. S. state and Federal laws regulating hoisting and wire rope use are also presented and discussed. Canadian and other foreign hoisting practice and laws are included. The state of the art in electromagnetic nondestructive inspection of hoist ropes is presented. Capabilities and use of one Canadian electromagnetic device are discussed in great detail. Conclusions are drawn regarding the present state of wire rope and hoisting technology in U. S. coal mines. Recommendations are made for improving rope practice, in general, and hoisting, in particular, consistent with greater safety.

Jan 1, 1971

By R. B. Crookston

Oil shales differ from coals in that they contain less carbonaceous material, convertible to volatile hydrocarbons, and more inorganic rock. In all pre-commercial oil shale development, involving extensive full scale mining operations, there have been no explosions. However, large scale mine tests with oil shale dusts by the Bureau of fines showed that propagating explosions could be induced under certain circumstances. Laboratory tests were conducted on a broad spectrum of oil shale dusts to define chemical properties and to seek correlations with subsequently determined fire and explosivity properties. These latter properties, indicative of safety hazards, increased as the Fischer assay oil yield of the dusts increased and as particle size decreased. Laboratory data were used to relate fire and explosivity properties of oil shales to those of coals and other carbonaceous materials and to assist in the identification and evaluation of potential hazardous situations which may be encountered in oil shale mining and processing.

Jan 1, 1978