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By Scott Turner

Within recent years , people have begun to realize the importance and significance of the mining and allied industries . The leading part the engineer plays in civilization is becoming recognized . However , accurate quantitative knowledge of the industrial importance of mining is still seldom possessed except by those close to this business . It is true that there are a few who go to the extreme and represent the whole progress of civilization as a reflection of man's gradual mastery of mineral utilization , but on the whole , the magnitude of the industry is underestimated . The uncertainties of mining , as evidenced by the variable results of prospecting on surface or underground , in an unknown new field or from the bottom levels of a mature mine , the ins and outs of tonnages and metal contents , the possibility of a widespread or even a sudden change between cost and realization-price , add to its picturesqueness and make mining attractive to some . To many , the fact that results are generally more uncertain and less predictable than in other industries lends added charm . The following pages may serve to call attention briefly to the importance of mining relative to other industries in the United States , in Canada , and in the world . Ordinarily , the annual primary mineral production of the United States amounts to about 5 billion dollars . The average for the last five years has been a little over 5 billion dollars . Last year , sadly enough , it was less than 34 billions . Just now , we are on the decline , and have been for the past two years . In Canada , the 5-year average was about 268 million dollars . Last year it was 227 million . Due in part to gold output ( in 1930 , for the first time , Canada's gold production exceeded that of the United States ) , the Canadian average is holding up better than ours . It has been estimated that the average world mineral production over the past five years has amounted to about 12 billion dollars , while in 1931 it was less than 8 billions . The mineral industries are as indispensable for the conduct of modern society as are those of agriculture , but , in the United States at least , they receive far less recognition from the Government . With us , agriculture is fostered by a great department that is maintained by enormous appropriations , while the mineral industries get but little financial support . In the United States , in the calendar year 1930 , the value of production by these two industries were as follows : to 1 . Agriculture ( inclusive of forestry ) 9.9 billion dollars ; mining 4.8 billions ; ratio 2 Direct appropriations by our Federal Government were 109 million dollars to agriculture and 2.8 million to mining , a ratio of 39 to 1. Obviously this is out of balance to the extent of 19 to 1 in favor of agriculture .

Jun 1, 1932

By Harry E. Tuff

"This paper is based data obtained by the Bureau of Mines from some of the principal mine operators in Pennsylvania, in the course of a study conducted in cooperation with the U. S. Forest Service, with regard to economies that might be effected in the selection storage, and preparations of timber particularly treatment with preservative to prolong its life.The Pennsylvania anthracite region, considered as a single mining district is by far the largest user of mine timber of any mining district, either coal or metal, in the United States, and the bituminous districts of Pennsylvania rank second. The present annual consumption of mine timber by the coal-mining industry of Pennsylvania probably exceeds 100,000,000 cubic feet annually.In 1919, Pennsylvania produced, in round figures, 145,300,000 tons of bituminous coal, 86,200,000 tons of anthracite, and 5,400,000 tons of iron ores. If it be assumed that the bituminous coal mines required 0.33 cubic feet, anthracite mines 0.7, and iron mines 0.9 cubic feet per ton mined the timber requirements were bituminous. 47,950,000; anthracite, 60,340,000; iron mines, 4,860,000 or a total of over 113,000,000 cubic feet.The average cost of round mine timber in the anthracite region in 1905, was, according to the U. S. Forest Service, 6.6 cents per cubic foot, and $15.00 per 1000 board feet for sawed timber. The present cost Las advanced to 27.5 cents per cubic foot for round timber, delivered to the mine, of which cost 57.4, represents freight charges."

Nov 1, 1923

To predict the spontaneous combustion potential of bituminous coals using a simple expression based on an easily acquired coal property. Background Approximately 20% of underground coal mine fires in the United States since 1978 have been attributed to spontaneous combustion. Spontaneous combustion fires in underground mines are most likely to occur in gob area; and are difficult to detect and to extinguish by direct fire fighting methods. Often, sections of the mine or the entire mine must be sealed for long periods, at a great economic loss to the mine operator, mine employees, and the surrounding community. It is conservatively estimated that the cost of scaling a large mine is about $50 million.

Jan 1, 1989

By G. L. Oldright, Virgil Miller

"This paper is the tenth 4 of a series on smelting in the lead blast furnace, and the fifth 5 on modifications brought about by the introduction of richer charges.ACKNOWLEDGMENTSAll of the data on handling rich charges in lead smelting given in this recent set of five articles describing the results of a cooperative study by the United States Bureau of Mines and the University of Utah were obtained through the courtesy and with the cooperation of the staff of the Bunker Hill & Sullivan Mining & Concentrating Co. at Kellogg, Idaho. The authors acknowledge with appreciation the assistance given by Stanly A. Easton, vice.-president and general manager, F. M. Smith, smelter director, and A. F. Beasley, smelter superintendent, whose generosity, sympathy, and assistance made it possible to obtain this information for the mining industry.GENERAL DISCUSSIONWhen the charge has been dropped into the lead blast furnace, it is out of control of the operator to the extent that, whatever the material is, it must practically all be melted and run out of the blast furnace. The necessary uniformity of mixture to produce slags of regular composition and the choice of the slag—forming ingredients and products to be formed can be made only before the charge to dropped.It was found (R.I. 3096) at Kellogg, where the charge is mostly sinter, that the ratio of the slag—forming ingredients taken from each tuyere was nearly constant, in contrast to the irregular composition of slags taken similarly from a furnace whose charge consisted of ingredients differing greatly in chemical and physical nature, including size. If the charge consists almost entirely of sinter, the blast furnace should then operate more uniformly."

Aug 1, 1932

By R. V. Ramani, C. B. Manula, A. Owili-Eger

Recently, a collection of programs that will simulate a ventila¬tion system with extensive analyses and report-generating capabilities and error diagnostics has been developed (Didyk, 1974). It has pro¬visions to handle air injections, methane or gas emissions, and leakage. Additionally, it will solve problems where fixed and/or maximum air quantities are specified for some airways. Finally, the simulator has been structured to be extremely modular so that additions and revisions to the model can be easily made. The general aspects of the information flow and logical structure of the mine ventilation simulator are shown in Figure 14. The output from the methane emission model is input into the ventilation simulator for calculation of the concentrations in all branches of the network. The methane model and the ventilation simulator provide powerful tools for the analysis and planning of mine ventilation systems. INPUT DATA REQUIREMENTS In all of the mathematical models, several coefficients that de¬fine the characteristics of the ventilation system are used. For the ventilation simulator, these include the frictional characteristics of the ventilation regulatory devices. Considerable work has been done on the experimental determination of these coefficients for smooth pipes and well-defined mediums, but only limited data are available for actual mining conditions. FRICTION FACTORS: The frictional characteristics of mine airways affect both the dispersion of pollutants and air flow through the roadways,. They

Jan 1, 1975

By Ralph B. Adair

The Bureau of Mines conducted laboratory and continuous pilot plant flotation tests to determine the feasibility of recovering commercial-grade mica from an Alabama graphitic-mica schist. Preconcentration of the ground ore on a Humphrey's spiral was employed to reject the heavy minerals and part of the quartz in a product virtually free of mica. The acid-cationic mica flotation process recovered over 89 percent of the mica in a product containing 98.7 percent mica. Grinding of the mica concentrate in a fluid energy mill produced a product with a bulk density of 12 lb per cubic foot.

Jan 1, 1969

By T. A. Sullivan

Refining in a molten salt electrolyte was investigated as a means of recovering nickel containing less than 1 percent and preferably less than 0.2 percent cobalt from nickel products containing up to 5 percent cobalt. Electrolytic separation of nick and cobalt was accomplished in a molten KCl-LiCl-NiCl2 electrolyte. Nickel containing less than 0.10 percent cobalt was routinely prepared. Factors that influenced the transfer of cobalt to the refined product were the nickel concentration of the electrolyte, the cobalt concentration of the electrolyte, the ratio of nickel to cobalt in the electrolyte, and cathode current densities. A method of recovering the cobalt from the electrolyte was developed. The possibility of preparing high-purity nickel by this process was shown, as well as the preparation of various cobalt-nickel-tungsten alloys.

Jan 1, 1968

By John C. Franklin

A radon survey was made at five different locations in the Twilight mine near Uravan, Colo., to determine chances in radon concentrations in an inactive mine. Data were taken with a continuous monitor set for 1-minute count periods and readings were taken 24 hours a day for 9 days. The 12 readings per station each hour accurately showed how t w radon concentration varied during the day. From the data collected from the intake portal to station 4, the average radon emanation rate was estimated at 18 picocuries per second per square foot (pCi/sec/ft3). A daily cycle in radon concentration was detected that apparently was related to barometric pressure change.

Jan 1, 1976

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

SUMMARY AND CONCLUSIONS This report describes a study to develop a detailed set of guide¬lines and equipment recommendations to be used as a guide for mine operators, mine inspectors, and equipment manufacturers in implementing the emergency escapeway standards for metal and nonmetal underground mines. It was sponsored by the United States Bureau of Mines. The first part of this report reviews the historical background of metal and nonmetal mine fires and the development of present and proposed mandatory standards. This is followed by a discussion of the survey of representative mines and how the proposed standard effects these mines. The remainder of the report covers technical discussions of each escapeway component including a comprehensive computer sim¬ulation of mine evacuation. Following the technical discussion of each group of escapeway components is a list of the pertinent guidelines. A study of past mine fires indicates that a serious commitment by operators to the proposed escape standards would be instrumental in saving lives in the future. The most significant event in a recent mine fire, in which no deaths resulted, was the very early discovery of the fire. The evacuation was orderly thanks to careful preparation by the mine personnel. However, the mine was possibly only spared a real disaster because of the discovery of the fire almost at its inception. Installation of automatic fire and smoke warning devices may be the single most important step in preventing future disasters. The self-rescuer has saved many lives in mine fires. Men have also died while attempting to use them. The reason men died was either because the unit was not working or the miner did not understand how or when to use it. There is no good excuse for either of these conditions occurring. Regular maintenance and inspection should prevent unit failures. Frequent instruction on when and how to use the self¬rescuer would prevent confusion and potential fatalities. A means of

Jan 1, 1976

By Lloyd R. Michels, Burke Cartwright, S. F. Ravitz

"INTRODUCTION Frequent attempts have be,made in the electrolysis of molten magnesium chloride to regenerate the electrolyte by allowing the chlorice generated at the anwdo to read with magnesium oxide and carbon within the melt according to the following reactions: (1) MgO + C + CL2 = MgCl2 + CO,(2) 2MgO + C + 2C12 = 2MgC12. + CO2.The principal advantages of such a procedure are that (1) the direct source of magnesium is magnesium oxide rather than the more expensive dehydrated magnesium chloride and (2) it is not necessary to handle or dispose of large quantities of chlorine or hydogen chloride.Grätzll 5/ proposed the use of an MgO carbon feed in a more or,less compact form in the anode compartment, of the cell. In a patent issued to Magall Aktiengecellschaft, 6/ a compact mixture of MgO and carbon is used as the anode itself. Kato 7/ and Backer 8/ add the feed in finely divided form to the surface of the anode compartment. The Bureau of Mines 2/ recently made a pilot-plant investigation of the electrolysis of suspension of MgO and carbon from chloride melts, in which it was found that although,current efficiencies of 60 to 70 percent were obtainable, the formation of sludges containing MgO, carbon, and magnesium seriously interfered with the operation of the cell,"

Apr 1, 1945

By R. V. Ramani, S. Shankar

"A convective dispersion model has been utilized to calculate the real-time airborne dust concentration in mine airways using re-entrainment as the only source term for airborne dust. It incorporates two important sources of re-entrainment in mines -- air velocity and movement of objects. The model has a sink term accounting for the deposition of particles along the airway. The model is solved using a finite difference scheme which is coded for computer. The computer model outputs airborne respirable and total dust concentrations along the airway as a function of time. The real-time and average gravimetric concentrations from several in-mine experiments were compared with the results from the simulation of the experimental conditions. This model can be used for estimating airborne dust entrainment due to air velocity, equipment movement, and persons walking. INTRODUCTIONEdwards and Ford (1988) developed a model for coal dust explosion suppression and utilized a predetermined value of threshold velocity for flowing air to pick up dust from floor. Depending on the strength of the removal forces, re-entrainment can increase the airborne dust concentration in mine airways. The most prevalent forces causing re-entrainment in mine airways are the drag and lift forces due to flowing air, and removal forces due to the movement of persons and vehicles. Shankar and Ramani (1991) have investigated the unique characteristics of the re-entrainment phenomenon in mine airways. Experiments on re-entrainment of coal dust particles were conducted in mine airways, and in a wind tunnel (Shankar and Ramani, 1994a, and 1994b). The results from the two experimental studies were found to compare well (Shankar and Ramani, 1995). There is no reported model to determine the airborne dust concentrations due to airflow or persons walking under conditions existing in mines. The present study is a part of a continuing research project in the Generic Mineral Technology Center for Respirable Dust on the spatial and temporal behavior of airborne dust in mine airways (Ramani, 1983)."

Dec 1, 1996

By Gordon L. Kinney

The only economically important mineral currently produced in Bangladesh was natural gas. Bangladesh was not a world? ranked producer of any mineral commodity, but the possibility of producing and exporting commercial amounts of liquefied natural gas (LNG) was being examined. Proved reserves of natural gas were sufficient to supply most of the country's industrial and domestic heating and electric needs and still support an export-oriented LNG plant. Other mineral production was of virtually no significance to the economy, although there were a few prospects for nonmetallic mineral development. Bangladesh continued to make economic progress during 1978 and into early 1979. Gross domestic product (GDP) at current prices rose from $6.6 billion in 1976-772 to $8.2 billion in 1977?78 and $9.3 billion in 1978.79.2 In fiscal 1979, the economic conditions were favorable until a severe drought hit most of the country. It W88 reported that conditions were the worst in 40 years, and 88 of July 1979, substantial crop losses were predicted. The agricultural sector accounts for over 53% of the GDP and about 75% of all employment. The poor weather will cause economic problems in the form of slower growth, larger trade deficits, and a higher rate of inflation. The 1978.79 statistics showed that real GDP increased just 4%.

Jan 1, 1981

By V. E. Erwin, W. W. Adams, E. V. Walters

"Increased production of explosives in the United States in 1933 compared with 1932 is shown by statistics compiled by the Demographical Division, Health and Safety Branch, United States Bureau of Mines. The figures relate only to explosives used for industries purposes, such as mining, quarrying, and road building, and do not cover nonindustrial explosives, such as ammunition or fireworks. Industrial explosives include black blasting powder, permissible explosives, 5 and high explosives other than permissibles figures in the tables of this report were compiled from reports covering sales by the individual companies manufacture of explosives in the United States in 1933. Because of the close agreement among the several series of figures, the quantity of explosives sold is considered as reflecting production and consumption, and the three terms ""sales"", ""production"", and ""consumption"" are used interchangeably in the discussion unless otherwise stated.Of the principal industries that use high construction operations accounted for the largest percentage of increase in consumption during 1933; metal mining and quarrying also used more of this class of explosives than in the previous year. Coal mining is the chief consumer of permissible explosives; the figures for 1933 showed that bituminous-coal mining used a larger quantity than in 1932, and that anthracite mines also showed a small increase. Although a net increase of less than 1 percent in consumption was reported for black blasting powder, large increases in use of this class of explosives were reported for metal mining, miscellaneous types of work, and bituminous-coal mining. (See table 1.)"

Nov 1, 1934

By J. P. Hansen

The Bureau of Mines has investigated the S02 leaching of MgO from high-MgO-bearing Florida phosphate concentrates. The S02 was effective in leaching some of the MgO from three phosphate concentrates; flow rate of the S02 and leach time were major factors in determining the amount of MgO leached. Calcining the samples, then grinding to minus 200 mesh, and elevating the leach temperature gave only small increases in the amount of MgO leached. The research also showed that some of the MgO was so intimately associated with the phosphate mineral that it could not be removed by S02 leaching. This amounted to about 0.6, 0.7, and 1.0 pct MgO in three leached residues. The calculated heads for the three concentrate samples averaged 1.4, 1.1, and 1.5 pct MgO, respectively, before leaching.

Jan 1, 1985

By Robert E. Manning

The Federal Coal Mine Health and Safety Act of 1969 has placed stringent limitations on the noise levels in which employees may work. This act can result in both increased labor costs because of noise-exposure time limitations and in high capital costs for modification of present equipment, and the design of new equipment, to comply with the law. The development of new noise-control systems is thus of immediate interest to industry. A current Research program at U. S. Steel is aimed at developing methods of controlling both the exhaust-air noise and the mechanical noise of a Stoper drill, a pneumatic percussive tool used for roof-bolting purposes in coal mines which has an approximate air consumption of 100 cubic feet per minute. This program is being performed under a contract between USS Engineers and Consultants, Inc. and the Pittsburgh Mining and Safety Research Center of the U. S. Bureau of Mines. In previous work at U. S. Steel, kidney-shaped mufflers were designed that wrap around the air leg of the drill for control of the exhaust noise. These mufflers were designed with the aid of a digital computer program that predicts the acoustic performance of mufflers.

Jan 1, 1975

By Richard Rittenhouse

This program was to develop a new base line system for automated continuous room and pillar type mining. The primary requirement estab¬lished for this machine is that the machine be capable of mining and bolting simultaneously. Additionally, this machine was to provide temporary and permanent roof control, have a productive - full - face semi-automatic mining system, leave a clean entry outby the machine, provide maximum operator protection, provide effective dust suppression and provide air scrubbing to restrict respirable dust to permissible levels. The machine has effectively demonstrated the ability to mine and bolt simultaneously. Additional above ground operation, testing, and time studies are recommended to further verify the machines abilities. Design improvements are recommended for future generation AES machines. These relate to marginal design areas such as side loading on vent duct lift cylinders, etc., that will not impair additional testing of the existing machine.

Jan 1, 1983

By David K. Hylbert

This study investigated stratigraphic and structural causes of roof falls in room-and-pillar drift coal mines in nine mines in eastern Kentucky. A contract modification provided for remote sensing studies in the Dunkard Basin of West Virginia and Pennsylvania. Results of stratigraphic and structural studies of an earlier contract (H0133018) were applied to several new mines. It was found that similar rock sequences contributed to unstable roof conditions. Structure contour and isopach maps were found useful In projecting these trends together with fence diagrams. Using Landsat imagery, a direct relationship was found between lineament direction and the trends of rock jointing, roof fall zones, "snap top" zones and sandstone channels in the examples cited. It was found that, by analyzing lineament intersections, from 50 percent to 65 percent coincided with roof falls.

Jan 1, 1980

By Sam Friedman

The Bureau of Mines conducted experiments using bench-scale apparatus to explore the effect of large changes in process variables on the yield and composition of the gases produced by passing 800° C steam through a fixed bed of Pittsburgh seam (hvab) coal. The total yield of combustible gases increased throughout the given range for the following variables: Superficial steam velocity increasing from 0.02 to 0.12 fps, pressure increasing from 1,000 to 6,000 psig, residence time increasing from 0 to 60 minutes, and temperature increasing from 800° to 900° C; however, a greater increase in the yield of hydrogen in comparison with the increase in yield of methane reduced the gross heating value of the gas to around 470 Btu per scf at conditions giving the maximum yield. Pressures of 1,000, 3,000, and 6,000 psig at 0.09 fps steam velocity, 800° C, and 60 minutes residence time, respectively, produced methane yields of 20, 24, and 22 percent, based on maf coal, with the gross heating value of the CO2-free gas decreasing from 552 to 520 and to 470 Btu per scf. Methane concentrations in the CO2-free gas were 26, 22, and 14 percent, respectively. Based on the gross heating value of the coal, the percentage of the heating value recovered in the gas was 60, 71, and 87 percent, respectively. The use of tungsten sulfide as a catalyst for converting carbon oxides and hydrogen into methane was explored briefly using both a sulfur-free gas rich in methane and a sulfur-bearing synthesis gas (3H2:1CO).

Jan 1, 1968

By M. Kanefsky

Two channel polarity coincidence and polarity difference statistics are analyzed. The signal, common to both channels, consists of sinusoidal bursts where the exact frequency of the signal is nearly known, but other parameters such as amplitude, phase, and pulse starting time are unknown. The noise inputs are dependent, narrow band, Markov processes. It is shown that the performance depends not only on the signal uncertainties, but on the precise shape of the cross-correlation functions between the noise in-puts. By using two polairty difference statistics in addition to the polarity coincidence statistic, it is shown that the decrease in performance, as well as the cost of hard limiting due to correlated inputs, can be made small.

Jan 1, 1981

By T. D. Moore

Methane emission from two surface gob-degasification boreholes was measured by the Bureau of Mines. The investigation took place during mining of a 3,200-foot longwall panel in the Lower Kittanning coalbed in central Pennsylvania. The first hole was 500 feet from the start of mining, and the second hole was 2,200 feet. The first hole went on natural draft as soon as the longwall face passed it. This caused the methane flow in the return entries to drop 75 pct. In the 6 months required to complete the panel, the two holes emitted 69 MMcf of methane in varying percentages of concentration in air. In 3 years, the holes emitted a total of 150 MMcf of methane.

Jan 1, 1976