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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 R. O. Dannenberg

Exploratory research was conducted to ascertain the feasibility of recovering beryllium from Spor Mountain, Utah, ore by the sodium fluosilicate (Na2SiF6) method used industrially for processing beryl. Na2SiF6 requirements to form water-soluble salts of beryllium were determined for three different samples--two clayey ores containing 0.6 and 1.3 pct BeO, respectively, and a calcareous ore containing 0.6 pct BeO. The ores were sintered with Na2SiF6 at 750° C for 3 hours. About 80 pct of the beryllium was rendered water soluble by sintering the 0.6-pct BeO ores with 30 and 40 lb Na2SiF6 per lb BeO contained in clayey and calcareous ores, respectively. The higher grade 1.3-pct BeO clayey ore required only 20 lb Na2SiF6 per lb BeO to solubilize over 80 pet of the beryllium. As the 0.6-pct BeO clayey ore was possibly the most representative of the deposit as presently delineated, leach liquor prepared from this sample was treated to recover beryllium salts. About 60 pet of the beryllium contained in the ore was recovered as beryllium hydroxide, which then was calcined to yield a 99-pct BeO final product by means of the following operations: (1) Sintering with Na2SiF2, (2) leaching with water, (3) precipitating crude Be(OH)2 by adding NaOH, (4) filtering to separate the hydroxide from the NaF solution, (5) redissolving the crude Be(OH)2 in excess NaOH, (6) filtering to reject caustic-insoluble impurities, and finally (7) boiling the Na2BeO2 filtrate from (8) to precipitate pure Be(OH)2. Reagent consumption was 49 lb Na2SiF6 per lb BeO recovered and 17 lb NaOH per lb BeO.

Jan 1, 1963

By D. B. Dow

The appearance of water in an oil field is the forerunner of various difficulties, and probably represents the greatest technical problem that the producer must face. Water conditions bear-directly on the quantity of oil recovered, and the length of the life of a field. Presence of mater increases the cost of operation, for example, gifting costs. On account of the corrosive action of oil-field waters on pumps and other equipment, frequent replacement of equipment is necessary. Furthermore, water may affect the marketability of the oil produced, as detrimental emulsions of water in oil (?B.S.?, "cut oil", etc.) are often formed. The writer has recently completed a study of oil-field emulsions. The present paper deals with the factors responsible for the formation of emulsions. This will be followed by another dealing with methods now utilized for dehydrating oil-field emulsions, and by a third dealing with the physical chemistry involved in the formation and resolution of such emulsions.

Jan 1, 1925

By V. E. Edlund

Laboratory batch flotation tests were conducted on copper converter slags to evaluate the relative merits of recovering copper from slow-cooled versus water-quenched slags. Three slags containing 1.6, 5.0, and 6.6 percent copper were used. More than 90 percent of the copper was recovered in a rougher concentrate leaving a 0.2- to 0.3-percent copper tailings when treating slow-cooled slag. Lower recoveries and higher copper tailings ranging from 0,5 to 0.6 percent copper were obtained from quenched slag. Grindability studies were made on the respective heat-treated slags. Quenched slags proved more difficult to grind than slow-cooled slags. Cost studies showed that (1) the cost of slow cooling and crushing off-sets any advantages of higher copper recoveries from slow-cooled slag, and (2) water-quenched slag, which requires no crushing preparatory to grinding, could be treated more economically. Costs based on processing 1,000 tons of slag per day would be $1.85 per ton for quenched slag versus $2.37 per ton for slow-cooled slag.

Jan 1, 1971

By Donald W. Mitchell

Certification tests for urethane-foam systems and techniques for apply-ing foam safely in mines are described. Fire hazard from foam exists if flame propagates beyond the ignition source or penetrates the foam. Foam that passes the certification tests can be applied on stoppings, continuous sections of ribs of relatively wide passageways (with no foam on the roof), short sections of roof such as overcasts, roof cavities, and intersections (with no foam on the ribs), and between buntons on one wall of a shaft. Foam on the ribs and adjoining roof presents a fire hazard. Stoppings covered with foam passing the certification tests are resistant to penetration of heat, flame, and smoke than similar stopping without foam. Flame propagation can be arrested by water sprays. Spontaneous ignition of foam can be prevented.

Jan 1, 1966

By S. H. Ash

The Pennsylvania anthracite-mining region is the only one in the world of major magnitude. As the deposits of anthracite in the United States are limited virt113.lly to Pennsylvania, the difficulties of this industry have been commonly considered a State rather than a national problem. However, there is also national interest in the conservation and wise utilization of all fuel resources and in the control of interstate waterways. The anthracite industry is confronted with the very se:;-ious :problem of accumu.lation of water in many of the mines. This problem must be solved soon if progressively higr-er mi~ing costs are to be avoided. The water proble~ cannot be solved by the operating compa,nies without State or Federal aid, or both, owing to the magnitude of the work requir~d, diversity of interests of the coal ana surfa.ce ovmerships, hazard to the whole mining community, and interests affec~ed outside the mining region. The cost of abati~ the ever-increasing_surface seepage to mine workings and of handling this seepage once it }3s occurred is beyond the economic resources of most ope~ating ma.'18.gements. The data in this paper giving the high lights of the water problem and indicating what appears to be a step in the right direction are based upon observations made during the past year that the industry desires and believes it is to the npublic interesttr to keep mine workings free of flood end surface waters.

May 1, 1941

By D. Harrington

Fine ventilation was discussed. much more 15 to 20 years ago than it is now, yet today there are tendencies in connection with ,-line ventilation (in fact, numerous ventilation systems have been installed in recent years) indicating that the lessons learned by bitter experience in the past either have been forgotten or lave not been brought to the attention of the present generation. Possibly, the mining min of today considers that conditions have changed so much that experiences of the past cannot be repeated today. At any rate, it seems desirable to restate some of the principles of mine ventilation that were understood more or less in the past and to call attention to some danger in connection with present-day trends or practices.

Jan 1, 1939

PURPOSE: Evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. RESEARCH SUMMARY: The results of previous NIOSH research show that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and gender. Using hearing thresholds at 4,000 Hz as an indicator, coal miners experience hearing loss 2.5 to 3 times greater than would be expected for persons not exposed to occupational noise. At age 50, 90% of coal miners and 49% of metal/nonmetal miners were found to have a hearing impairment. In comparison, only 9% of a nonoccupationally exposed control group had a hearing impairment at age 50.

Jan 1, 2000

By Ben E. Lindsly

The study of "bottom-hole samples follows in natural sequence the study of samples obtained under high pressures at the well heads of flowing wells. The principal object of this phase of gas-solubility research, started actively in January, 1930, was to gain a more accurate knowledge of the physical and chemical characteristics of the oil-gas mixtures that exist in natural reservoirs.. In possession of actual data regarding the condition of the oil; the quantity of gas liberated from solution upon dimunition of pressure; and the relative volumetric proportions of gas to oil at various pressures throughout the flow string in a well, it should be possible to predict, with a fair degree of accuracy, That physical changes these mixtures would undergo throughout the life of a pool. Such information not only is important in designing flow strings in flowing Tells but is important also in solving problems relating to pumping efficiency and the power required for pumping. Although certain fundamental data were obtained in the study of samples taken at the well head, "bottom-hole" samples are more representative of subsurface mixtures of oil and gas because they are obtained at reservoir temperatures, and before the oil has had the opportunity of intermingling with extraneous gas; that is, gas which either was not in solution originally, or which was liberated from solution at higher pressure, and later became mixed with the original undissolved gas.

Jan 1, 1933

By N. C. Tomoeda, W. D. Bensema, J. W. Adams

Measurements of surface magnetic field noise were made at various locations over the Geneva Coal Mine near Price, Utah, on June 12, 1973. The locations selected were on the surface over emergency locator beacons underground at depths between 350 meters (1150 ft .) and 488 meters (1600 ft .) . The surface terrain where these measurements were made was mountainous, and access was difficult. There were no power lines within several miles, and the weather was clear; therefore, the magnetic noise levels were about as low as will normally occur. Results of measurements of distant sferics indicate rather sharp cutoff frequencies below which broad- band, impulsive noise is attenuated. The mechanism of propagation for this noise above the daytime cutoff frequency of 3500 Hz and the nighttime cutoff frequency of 1700 Hz is deduced to be a waveguide formed by the D or E layers of ionosphere as an upper plane and the earth as a lower plane. The measurement systems used are similar to those used earlier. The technique is to record broadband, analog signals, digitize the data, and use a fast- Fourier transform to obtain spectral plots. This tech- nique is novel in that it can measure simultaneously all magnetic field energy within a limited portion of the spectrum for a limited time, and, after processing, reproduce the events occurring in that time interval in great detail .

Jan 6, 1974

By John S. Berber

Olefin and paraffin mixtures (C10-C16 and C10-C22) were separated from low-temperature lignite tar by urea adduction and sulfated to yield secondary alkyl sulfate detergents. The C10 ?C16 secondary alkyl sulfate showed a 99.3 percent biodegradability, and the C10-C22 fraction showed a 96.8 percent biodegradability, exceeding the required standard of 80 percent for the biodegradability of anionic detergents in washing and cleaning compounds. Chlorination of paraffins yielded a detergent of 93.2 to 93.4 percent biodegradability.

Jan 1, 1968

By Michael Rieber

Rail cars are referred to as "yellow-balled" when they are sufficiently old or damaged to preclude their efficient operation on long-haul or main line routes. For most coal carrying railroads, their alternative value is salvage. This, however, does not necessarily preclude their effective use, on a limited basis, by small mines located near existing trackage. Because of age, the sizes of these hopper and gondola cars ace currently 50 and 70 tons rather than the 100 tons commonly built at the present time. As a gathering system, yellow-ball rail could provide an alternative, particularly in Kentucky, western Pennsylvania and west Virginia, to coal trucks, conveyor belts and pneumatic pipelines [4, p.17], belts and pneumatic pipelines. Rail service of this type provides a limited alternative to track abondonment, a possible financial return to a railbank [3], a direct contribution to service demand on main lines, and a means by which many small eastern coal mines could retain or regain competitive viability [4]. In terms of energy efficiency, compared to trucking coal, the total direct energy impact (fuel) of yellow-ball rail can be expected to range from 280-990 Btu/ton-mile while that for trucks ranges from 1850-3120 Btu/ton-mile [2].

Jan 1, 1977

By T. H. Miller

This piper is a continuation of a series of yearly review articles started in 1925 by Thomas Varley. The development of flotation has been rapid, and better understanding of the functions o' flotation reagents has resulted in many changes in the kinds and quantities o reagents used. It is the purpose of this report to present the information in such a manner as to be of value to the milling industry as well as to the manufacturer of flotation reagents. These data have been compiled from a. survey of approximately 250 flotation plants of all classes within the United States. Many of these plants made complete reports of their operations, out others were apparently unable to supply this information in sufficient detail to meet the requirements of this investigation. Although it is realized that the data obtained in this survey are not as full as they should be to render the greatest service possible to the milling industry, it is hoped that succeeding articles will include complete information regarding milling; conditions and recoveries. As in the past, every effort has been made to conceal individual plant operations. RESULTS OF INVESTIGATION Table 1 gives the tons of ore treated by gravity and flotation methods and the concentrates produced as reported by 208 plants. The totals of 77,043,535 tons of ore and 4, 596,640 tons of concentrates from this table compare with totals of 78,973,012 tons and 4,683,972 tons respectively (furnished by the Bureau of Mines, Division of Mineral Statistics), indicating that the milling survey is about 98 per cant complete.

Jan 1, 1930

By Lloyd A. Morley, Robert Stefanko

Before going directly to the analysis, it would be good to summar¬ize explosion-proof container approval methods. Both Magison (52) and Short (84) state that in general practice, the systems are certified for: 1. a rugged enclosure able to withstand an internal explosion but not allow explosively hot gases to escape, and 2. maximum surface temperature, with equipment operating inside, that will not ignite the surrounding atmosphere. Also, testing insures that any material in contact with the container surface will not be ignited by a hot spot. Associated with the first practice, the enclosures are inspected for: 1. a safe flange gap width, 2. a pressure increase during ignition, and 3. an hydrostatic pressure withstand level. The hydrostatic pressure level is almost always determined by a meas¬ured ignition-pressure test and is usually applied to prove the mechan¬ical design to some safety factor. Consequently, explosion-proof enclosure testing includes temper¬ature, permissible flame gap, and pressure. Specifications and prev¬ious research also can be similarly separated even though some interre¬lation exists between the flame gap size and internal enclosure pressure during an explosion. The Schedule 2G Sections applicable to these subjects are: 1. 18.2 Definitions; 2. 18.6 Applications;

Jan 1, 1974

By S. R. Borrowman

Physical beneficiation, leaching, and solvent extraction investigations were made to recover a high-grade thorium oxide product from Bald Mountain, Wyo., conglomerate. The monazite in the Bald Mountain deposit contains 8.8 percent Th02 and, therefore, is higher in thorium content than the usual domestic or foreign monazite. A sample of composited drill cuttings for the study contained 4.3 pounds of monazite per ton of are. The work showed that the monazite, although unusually fine grained and friable, could be concentrated by tabling and magnetic treatment to yield a product assaying 5.65 percent Th02 with a recovery of 61 percent of the thorium. Subsequent decomposition of the concentrate by treatment with sulfuric acid and solvent extraction of the resultant solution with a primary aliphatic amine yielded a thorium oxide product of 99-percent grade.

Jan 1, 1962

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing gypsum mining and crushing methods and costs at various operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs may in many instances cause embarrassment to individual operators as well as to the industry as a whole. On the other hand, operating costs are essential to a technical discussion and study of the methods employed. The attention of the reader is called specifically to this differentiation so that there may be no misunderstanding of the scope of the cost tabulation. This paper deals specifically with the mining and crushing methods employed by Victor Plaster, Inc., Victor, Ontario County, N. Y. The maximum annual production capacity of this company is 150,000 tons of crushed gypsum. The methods and practices employed arc typical of those followed in the gypsum mines in western New York State. The shaft is, perhaps, the deepest and the thickness of the gypsum mined is above the average for the section.

Jan 1, 1937

By S. M. Shelton

The widespread occurrence of domestic manganese deposits and the shortage of ferromanganese-grade ore have been sources of much speculation and investigative effort for many years. The present emergency has intensified the search by the Bureau of Mines for methods of producing ferromanganese-grade concentrates4/ from low-grade ores.

Jan 1, 1941

By S. M. Shelton

[The widespread occurrence of domestic manganese deposits and the shortage of ferromanganese-grade ore have been sources of much speculation and investigative effort for many years. The present emergency has intensified the search by the Bureau of Mines for methods of producing ferromanganese-grade concentrates4/ from low-grade ores.]

Jan 1, 1941

By W. T. Abel

The Bureau of Mines tested 48 materials for their ability to absorb H2S from hot simulated producer gas (1,000°-1,500° F). The material found best from the standpoint of absorption capacity, durability, and amenability to regeneration was sintered pellets of 75 percent fly ash-25 percent Fe203. The performance of this absorbent under simulated and actual conditions is described. The effect of absorbent composition, absorbent temperature, steam content of the gas, and tar vapors and dust in producer gas is discussed.

Jan 1, 1974

By C. W. Davis

Two general schemes have been used for the determination of gold and silver in material containing considerable quantities of copper ; one is known as the " all fire " method , and the other as the , " combination " , or " wet and dry" method . The all fire crucible method , using an excess charge of litharge , has been found satisfactory when the copper content of an ore is under 6 per cent , ( Loevy , J. , Zur Edelmetallbestimmung in hochprozentigen Kupfererzen : Chem. Ztg . Jarhrg . 35 , 1911 , p . 278 ) , or where the precious metal value is so great that a small sample can be used . In the latter case , silica is added until the copper ratio is sufficiently low . If there is more than 6 per cent of copper in an ore , the lead button obtained from a crucible fusion will require repeated scorification before . it can be cupelled successfully . Rescorification is not only tedious , but also causes a slag loss of precious metals . In combination methods , the copper is dissolved , and the gold and silver in the residue . is determined by fire assay Although some combination methods have given satisfactory results for gold and silver , they are not applicable when an estimation of the platinum metals is required . Since substances containing platinum are frequently high in copper , a study of methods which might be used for the estimation of small quantities of gold , silver , and the platinum metals in such material was considered worth while . The estimation of platinum in ores by fire assay methods has been described in Technical Paper 270 of the bureau; ( Davis , C.W. , The detection and estimation of platinum in ores : U. S. Bureau of Mines Tech . Paper 270 , 1921. ) the present paper , which is supplementary to that report , deals chiefly with the application of combination methods , taking them up to the point where the fire assay is to be applied .

Mar 1, 1921