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By Charles L. Kimbell

Virtually every available measure of total world mineral industry activity demonstrated that 1982 was little, if any, better for the industry than 1981 had been. Levels of production, trade, and consumption for virtually every major commodity declined; unit prices for most commodities fell, particularly in terms of constant dollars, and as a result of cutbacks in output and lower prices, capital available for investment within the industry was reduced. These conditions, coupled with the existence of considerable idle capacity, tended to retard investment, although there was an upturn in U.S. oil industry investment overseas. Despite the overall depressed situation of the world's mineral industry, there were indications of possible improvements in market economy countries near yearend, as output of some materials increased marginally and as prices for some mineral commodities reversed their downward trends. The downturns in total world mineral industry activity were not universal from the viewpoint of individual countries. Indeed, output of a number of commodities increased in centrally planned economy countries, and these gains were insufficient to offset declines in market economy countries, thereby sharply altering the proportion of total world output accounted for by each of these two groups of countries. There was a similar shift in consumption on a percentage basis.

Jan 1, 1984

By J. C. Edwards

A series of four coal combustion experiments (I)' was conducted at the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory in the Safety Research Coal Mine to evaluate the response of optical and ionization smoke and CO sensors to a small 0.61 m square smoldering coal fire which transitions to flaming combustion in the presence of diesel emissions. With the increased utilization of diesel engines in underground coal mines, it is important to be able to discriminate fire products-of-combustion (POC) from diesel emissions. One proposed method to accomplish this is the deployment and interpretation of multiple sensors.

Jan 1, 2010

By L. C. IlsLey, M. W. Von Bernewitz

"Introduction.Several hundred thousand open lights are daily carried in coal mines of the United States, each lamp being a menace to life and property through fire or explosion. They have been responsible for many disasters in the past, and will be again. Flame safety lamps have been available for over a hundred years, but during the last ten years safe and practical electric lamps have been perfected. These have eliminated many of the flame safety lamps, and in a few mines have replaced open flame lamps. But there are still more than twice as many open lamps as electric lamps in our mines, and the open lamps should be discarded in favor of an approved type of electric lamp. There are several electric miners' lamps which have been approved by the Bureau of Mines for safety and efficiency, give good light, and are easily maintained and carried, some flame safety lamps will always be used, hut mostly for detecting gas; although they might be supplanted if some simple, reliable, and cheap gas detector were developed.Explosion Hazards from Open Lights.An open light and gas*** constitute a vicious hazard; while if there be coal dust present in the vicinity the consequences are multiplied many times. An open light and black blasting powder also constitute an explosion hazard, vividly attested by several serious disasters."

Jan 1, 1924

By Thomas H. Dubaniewicz

Thirteen miners died as a result of 2 explosions in the Jim Walter Resources No. 5 mine near Brookwood AL in September 2001. Both explosions were ignited in intake air entries, and both were probably ignited by electrical equipment. With few exceptions, permissible equipment is not required in intake air entries of US underground coal mines Researchers with the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory. studied the electrical equipment ignition sources for the Brookwood and other w disasters to develop recommendations for preventing similar disasters Adherence to National Electrical code® requirements for flexible cords installed in hazardous (classified) locations may have prevented the second massive Brookwood explosion. The 30 CFR Part 7 requirements for battery assemblies should be reevaluated, taking into consideration United Mine Workers of America recommendations and the Zone 1"increased safety" standard requirements for battery assemblies, Class 1 Division 2 or Zone 2 explosion protection techniques are recommended for intake air equipment so that they do not present a methane air ignition source under normal operation before mine power is shut down during emergencies Battery powered circuits intake air that are likely to remain energized during emergencies should be protected by more stringent protection techniques, to protect rescue/recovery personnel. Index Terms -Class 1 hazardous location, mine explosion, flexible cord, battery assembly, permissible equipment

By R. Barany

In this paper, closed expressions have been obtained for the frequency spectrum of a Born-Karman square lattice in terms of elliptic and hyperelliptic integrals. This work is part of continuing research by the Bureau of Mines with the thermodynamic properties of metals and minerals. Although other workers have obtained various types of approximations for the general case of the frequency spectrum of a square lattice, no one previously has obtained closed analytic expressions for this spectrum. To understand the optical and thermodynamic properties of crystals, several investigators have studied the distribution of frequencies of normal modes of vibration of the crystal lattice. Born and Karman3 laid the foundation for the theory of lattice dynamics and obtained detailed results for the case of a one-dimensional lattice. Blackman4 used numerical techniques to estimate the frequency distribution of a two-dimensional square lattice. Mbntroll5 analytically determined the frequency distribution of a square lattice for a particular value of the force constants. He also studied the more general problem and obtained some analytic approximations, using the method of moments. However, the calculations by this method were so difficult that it was not always practicable to carry them out. Van Hove6 and Montroll7 studied the nature of the singularities in the frequency spectrum of both a two and

Jan 1, 1962

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1981 was $312.7 million, a decrease of $15.7 million from that of 1980. Output of most non fuel minerals declined; cement, crushed stone, lime, clays, and sand and gravel were the major commodities produced in the State. Alabama led the Nation in the production of crushed marble; was second in bauxite; third in native asphalt, kaolin, and oyster shell; fourth in bentonite, dimension marble, and fire clay; fifth in masonry cement; and sixth in common clay, ferroalloys, and lime.

Jan 1, 1983

By Max F. Lee, Warren A. Peck

The applicability of the Q-system [Barton et al. 1974] to Australian underground metal mines is discussed with reference to two common design issues: ground support for horizontal mine development, and assessing the stability of bored raises. Installed ground support in mine development is com-pared to empirical estimates using the Q-system and associated support capacity calculations. Data are graphically presented from 59 specially selected sites at 15 contributing mines. The actual performance of large-diameter raise-bored shafts is also compared to empirical stability assessments using a modified version of Q (Qr, after McCracken and Stacey [1989]). Lower-bound Qr values are plotted against raise diameter for 47 selected sites at 23 mines in Australia and Papua New Guinea. The influence on Q and Qr of some geotechnical aspects of the Australian landscape, the dynamic nature of mines (compared to civil construction), and occupational health and safety regulations are discussed. Stability and support assessments that are based just on Q or Qr are not always conclusive. It is often necessary to consider other rock mass parameters, the regulatory environment, and risk issues. These results are interim; further data collection and analysis are required with regard to comparing actual performance versus empirical assessments.

Jan 5, 2007

By R. G. Gürtunca, J. A. Breslin

This paper briefly describes the progress in mine safety in the United States, with emphasis on recent events that have followed since the explosion at the Sago Mine in January 2006. Legislation following the mine accidents last year and areas of work carried out by the National Institute for Occupational Safety and Health (NIOSH) related to the accidents are discussed. American coal production in 2006 was 1,150 million short tons. Most of this coal is consumed domestically, with annual exports of coal about 50 million tons. One third of annual production is produced at surface mines and the rest from underground. This coal is produced by about 82,000 miners working at 1,400 coal mines. Major improvements in coal mine safety have been made in the US since the Federal Mine Safety and Health Act of 1977. The fatal injury rate in underground coal mines between 1977 and 2004 was reduced by 47.8% to 0.036. The annual number of fatalities dropped from 112 to 14 during that period. Likewise, the non-fatal days-lost injury rate was reduced by 42.6% from 10.87 to 6.24. The improvements in mine safety during this period can be seen in the graph of underground coal mine explosion fatalities and injuries from 1980 to present, which is shown in Figure 1. Between 1984 and 1993 (9 year period) there were 5 explosions and one major mine fire, for a total of 55 fatalities. Over the seven year period from 1993 to 1999 there were no fatalities from coal mine fires and explosions. However, in the six years since 2000 there have been 5 explosions and one fire, which have caused 37 fatalities. [ ]

By Robert R. Stein

Occupational noise caused by the rock drills used in mining was investigated by the U.S. Bureau of Mines. Using a large reverberation chamber and an automated drill test fixture (ADTF), the sound power levels of mining drills were measured to determine if there are types of drills that are advantageous from a noise production standpoint. Test results show that while there are not large variations among types of drills, there are still some choices that could produce a positive effect on overall noise exposure. It is also shown that lower noise exposures are possible using larger drills because of higher production rates and better operator positioning.

Jan 1, 2010

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 A. J. Kraemer

[A great deal of interest has been manifested in the question of sulphur in fuels for automobile engines. Many different opinions have been expressed with respect to the effect of sulphur in gasoline on engine wear and engine performance. A wide difference of opinion exists as to the permissible limit of sulphur content for satisfactory operation.]

Jan 1, 1927

By Gerald T. Homce, James C. Cawley

Arc flash generally refers to the dangerous exposure to thermal energy released by an arcing fault on an electrical power system, and in recent years, arc flash hazards have become a prominent safety issue in many industries. This problem however, has not been effectively addressed in the mining industry. MSHA data for the period 1990 through 2001 attributes 836 injuries to “non-contact electric arc burns”, making it the most common cause of electrical injury in mining. This paper presents results from several elements of a recent NIOSH study of arc flash hazards in mining, and provides information and recommendations that can help reduce these injuries. Characteristics of past arc flash injuries in mining are first outlined, such as the electrical components and work activities involved (based on MSHA data). This is followed by a review of important concepts and terminology needed to understand this hazard. Next, methods for identifying, measuring, and managing arc flash hazards on a power system are covered, with emphasis on recommendations found in NFPA 70E, Standard for Electrical Safety in the Workplace. Finally, results are presented from a detailed arc flash hazard analysis performed on a sample mine electrical power system using IEEE 1584-2004a, focusing on components and locations presenting severe hazards as well as engineering solutions for reducing the risk to personnel. Index terms – electrical arcing, electrical burns, mining, arc flash hazard analysis

By Victor Erickson

ECONOMIC recovery, which began in 1958, carried through into 1959 but was somewhat retarded by the 116-day steel strike beginning in July 1959. Recovery and economic growth increased production and consumption of mineral fuels 3 percent above 1958. The increase was accomplished despite a drop of 26 percent in coal exports. Prices remained constant during the year so that the value of production and consumption also increased 3 percent over 1958. Stocks in the hands of producers at yearend were little changed from the supply at the beginning of the year. Employment in the field of mineral fuels decreased 6.4 percent from 1958. Average hourly earnings were up 7 percent, and average hours worked were up 5 percent, with the result that weekly earnings gained 11.8 percent. Internal freight rates were relatively constant, but ocean tanker rates declined both in 1958 and 1959 from the high rates charged during the Suez crisis. The index of major input expenses decreased for anthracite, held constant for bituminous coal, and increased for petroleum. The index of labor cost per dollar of product and per ton of product declined again in 1959 to a new low in anthracite and bituminous-coal mining industries.

Jan 1, 1960

By Max J. Spendlove

This Bureau of Mines publication reviews current recycling trends in the United States. Although near-term prospects are poor for recycling most present wastes, urban refuse is an important exception. Such wastes comprise a mine above ground, and much less processing energy is normally required to recycle the constituents of urban ore than to obtain them in equal amounts from natural raw materials.

Jan 1, 1976

By James R. Boyle

The value of mineral production in-creased 13% in 1977. Nearly all commodities registered an increase in production and value, continuing a trend that started in 1976. In addition, practically all commodities registered an increase in unit value. Alabama led the Nation in the production of crushed marble, was second in bauxite and scrap mica third in kaolin and oyster shell, and fourth in bentonite, dimension marble, and fire clay.

Jan 1, 1981

By Avery H. Reed

RECORD production of portland cement, crushed limestone, marble, lime, and clays highlighted the mineral industry of Alabama in 1959. Among the States, Alabama ranked second in production of bauxite, and third in output of iron ore, scrap mica, and native asphalt. Alabama's mineral industry was dominated by the mining and processing of coal and iron ore, which accounted for 51 percent of the total value of production in 1958 and 1959. Other important industries were cement manufacturing, petroleum, and stone quarrying. Leading companies were Tennessee Coal & Iron Division of United States Steel Corp. (coal;. iron ore, limestone, lime, and magnesium compounds), Southern Cement Co. Division of American-Marietta Co. (cement, lime, limestone, and miscellaneous clay) , Woodward Iron Co. (coal and iron ore), Alabama Power Co. (coal), and Ideal Cement Co. (cement lime, and miscellaneous clay) .

Jan 1, 1960

By D. Bienstock

As part of the development of the hot-carbonate scrubbing process by the Bureau of Mines, the corrosion rates of steel in boiling solutions of potassium carbonate saturated with carbon dioxide and hydrogen sulfide were determined, and the effectiveness of various inhibitors was evaluated by Bureau researchers. The highly corrosive solution of carbonate saturated with carbon dioxide can be inhibited with a 0.2-percent concentration of either potassium chromate or sodium metavanadate. Solutions of carbonate saturated with carbon dioxide and hydrogen sulfide are mildly corrosive, 0.01 inch per year. Complete absence of corrosion is obtained with 0.2 percent sodium metavanadate or 0.15 percent vanadium pentoxide. Oxidizing inhibitors such as potassium chromate are destroyed in the alkaline sulfide mixture, N-alkyl trimethylene diamines, at a concentration of 0.1 percent, lower the corrosion rate to about 0.005. Sodium metasilicate, at a concentration of 0.6 percent, completely inhibits the corrosion but may deposit free silica in the system. Commercial cladding materials such as the epoxy coatings also prevent corrosion.

Jan 1, 1962

By F. E. Armstrong

The Bureau of Mines has conducted a research program to systematize the art of locating uncharted and lost oil and gas wells that penetrate coal seams; this publication presents a preliminary summary of its findings. Although no method or combination of methods will guarantee finding all uncharted and abandoned wells in a particular area, at least 75 percent of such wells can be located by compiling and applying all available information and using modern metal detectors.

Jan 1, 1973

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1986 was $405.2 million, a slight decrease from that of 1985. Alabama was second in the Nation in production of bauxite, crushed marble, and ferroalloys; third b fire clay; fifth in masonry cement and lime; sixth in total clays; and seventh in recovered sulfur. Alabama ranked 19th nationally in value of nonfuel minerals produced. Cement, clays, lime, sand and gravel, and stone were the major commodities produced.

Jan 1, 1988

By R. F. Stewart

A nuclear meter based on measurement of prompt capture gamma rays is being developed for monitoring the sulfur content of coal streams. Equipment has been built to measure sulfur rapidly, and methods have been devised to compensate for changes in moisture, ash, and bulk density of coal flowing through a bin. Pilot plant tests of the system with various additives to different coals show a precision and accuracy of 0.02 percent sulfur and 0.04 percent sulfur, respectively. Based on these results, a hardwired meter has been fabricated for testing in a commercial coal preparation plant.

Jan 1, 1974