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By John C. Edwards

The Bureau of Mines has developed a time-dependent mathematical model of radiative heating of bulkheads in mines. The model includes both reradiation from the duct (cylindrical) walls and direct radiation from the fire zone. Thermal loss into the wall of the duct and into the bulkhead is included. Both brick and wood bulkheads are considered. It is found that the heating rate of the system scales as the duct length-to-diameter ratio and the flame temperature. In particular, the time required for the irradiated surface of the bulkhead to reach a specified temperature decreases with increasing flame temperature for a fixed length-to-diameter ratio and increases with increasing length-to-diameter ratio for a specified flame temperature. It is also deter-mined that the time, T, for the bulkhead surface temperature to reach a specific value, Tb, for a fixed length-to-diameter ratio less than 4 and for a flame temperature of 1,200 K is approximately linearly dependent on Tb for 500 K < Tb < 700 K, and is nearly exponentially dependent on the length-to-diameter ratio for Tb = 600 and 700 K.

Jan 1, 1979

By V. D. Smar

The flotation process may be considered an interactive system consisting of many chemical, operational, and equipment variables. Changing anyone of these variables causes an overall system response change. This study examines the effects of simultaneously changing the operating variables of: (1) frother concentration and air flow rate, and (2) frother concentration and collector concentration. It is part of a comprehensive study to look at how changes in several of the major variables may be used to produce interactions which will allow the rougher flotation process to be optimized. Ultimate recovery, flotation rate, concentrate grade and froth quality, are used as the major evaluative criteria.

Jan 1, 1993

Since mid-July, most domestic producers have been marketing 99.5 percent unalloyed aluminum ingot at 53-57 cents per pound. Dealers in the United States have recently quoted ingot at 52.3-52.8 cents. On October 2, London Metal Exchange will trade aluminum, selling contracts on a cash and a 3-month basis. New York dealers were quoting August ingot at 52.3 52.8 cents. The Bonneville Power Administration announced that, effective December 20. 1978, electric power rates charged primary aluminum producers in the Pacific Northwest would be increased The increase (equivalent to about 4 cents per pound of aluminum produced) will raise the average rate to about 8.7 mills per kw-hr compared to 3.2 mills per kw-hr.

Jan 1, 1978

By John Stubbles

Data are presented on the global warming issue to reinforce the decision by the U.S to reject the Kyoto protocol. The evidence that CO2 is a problem rather than a benefit is inconclusive and will be discussed in this paper. Nevertheless, for economic reasons alone, the US steel industry will continue to minimize CO2 emissions (and the release of real pollutants) per ton of steel through energy reduction programs. However, relative to inevitable increases in absolute CO2 emissions from the utility industry and the transportation sector, future reductions by the steel industry will be inconsequential in the "big picture."

Jan 1, 2004

The 1990s present many challenges, not the least of which is in the area of health and safety. Integrating of safety and health into the management process to suit the overall needs of a company will require commitment. Organisations which consistently perform to high success levels do so because they plan it that way. By using tools of total quality management, the potential to continually improve all safety processes exists. The successful integration of total quality measurement principles used in the improvement of safety processes, and the measurement of performance-based activities allow for prevention of accident causing scenarios and performance improvement.

Jan 1, 1993

By John L. Bolles

The Phelps Dodge Corporation&apos;s Morenci Concentrator includes facilities for coarse crushing, fine crushing, grinding, flotation, tailing, disposal, concentrate filtering, and drying. The Morenci Concentrator daily throughput is in excess of 60, 000 tons. The ore milled is mainly a medium-hard monzonite porphyry in which the principal sulfide minerals are chalcocite and pyrite. The ore is transported by rail from the Open Pit Mine to the primary crushing plant located at the concentrator site. Ore is side-dumped from 80¬ton railroad cars into a sixty-inch gyratory crusher. The ore is then conveyed to a. 12, 000 ton coarse ore storage bin. Fine crushing is accomplished by four parallel lines of conventionally stacked crushers in open circuit. Each unit consists of one seven-foot standard cone followed by two seven-foot shortheads. Ti% product of the fine crushing plant is distributed by two tripper cars across a fine ore storage bin. The crushed ore is then fed by variable speed belt feeders into thirty parallel, single stage, closed circuit grinding units. Each of the 30 grinding units consists of one 6&apos; x 23&apos; conditioning drum, one 10&apos; x 10&apos; ha l mill and two 54" duplex spiral classifiers as principal equipment. The dry ore is fed into the conditioning drum with water to dilute the ore to a slurry of approximately 78% solids by weight. An aqueous solution of ammonium sulfide is also added to the conditioning drum. The ammonium sulfide primarily acts as a sulfidizing agent. The ore slurry containing the naturally occurring sulfide copper minerals and the sulfidized copper minerals discharges into the feed scoop box of the ball mill, where milk of lime, collector and-.dilution water are added. The ball mill product slurry is gravity fed: to the classifier pool where water is added to obtain the desired classifier overflow product

Jan 1, 1977

By Raymond L. Zahradnik

Marco Polo reported that the Chinese used "black rocks" for fuel, and recent studies indicate that the Chinese may have used coal in small amounts for two or three millennia previously. The use of coal as a major source of energy however, did not begin until about the twelfth century, when the inhabitants of the northeast coast of England discovered that certain black rocks found along the seashore--and thereafter known as "sea soles" would burn. Since this initial discovery, coal has been mined continuously, first in England and shortly thereafter in present Belgium, France, and Western Germany, and finally in all coal-bearing areas of the world, in ever increasing amounts. The production of coal in the United States began about 1820, when 14 tons were reportedly mined. Since that time the production of coal increased steadily until about 1907, after which the rate has fluctuated between the extremes of about 400 and 700 million tons per year. Bituminous coal and lignite production was 590 million tons in 1974. Value of production was $8. 9 billion. Anthracite production was b.3 million tons with a value of $157.5 million.

Jan 1, 1975

By J. A. G. Llerena, J. Sattarvand

Tailings dam failures have been occurring in recent years. They are considered more vulnerable than hydraulic dams due to the lack of regulations on specific design criteria, and stability requirements regarding monitoring during the construction and maintenance process. Thus, monitoring the dam is essential to know the dam's existing state and ensure its safety. One of the reasons tailings storage facilities fail is slope instability caused by moisture content. A relationship does exist between moisture content and surface strength, early detection of seepage would help to assess the physical condition of the dam. Moreover, to cover the tailings dam area in an efficient way Unmanned Aerial Vehicles (UAVs) are suitable because of their versatility and high-resolution data acquisition. Mounted with a high-resolution RGB camera, and thermal, or hyperspectral sensors UAVs can acquire good quality images that combined with image analysis and machine learning algorithms yield a good estimate of soil moisture.

Feb 1, 2023

By H. A. Dierks

The work and costs involved in controlling three large fires in abandoned mines in the anthracite region of Pennsylvania are presented in detail. The work was done under authority of Public Law 89-4. Three basic control techniques were successfully employed by the Bureau of Mines: (1) forming underground fire-containing barriers by systematically flushing incombustible material into mine voids, (2) excavating an isolation trench around the fire area, and (3) complete excavation of hot and burning material in the fire area. When methods 2 and 3 were used, the excavations were subsequently back- filled with incombustible material. Preliminary location of fire perimeters by the standard use of patterned 6- and 8-inch-diameter boreholes is discussed. Investigations into air-borne infrared scanning, shallow subsurface thermal anomalies, and the use of helium to trace the movement of mine air currents are covered. Although they are costly and time consuming, boreholes have proven to be the most efficient means to date of obtaining necessary subsurface fire data. Infrared scanning was ineffective in delineating fires under more than 30 feet of cover. Helium-tracing was shown to have a good potential for determining possible hazards to adjacent residential areas from traveling mine fire gases.

Jan 1, 1971

By J. M. Cooper

The HBMS reverb furnace in Flin Flon was originally designed in the late 1920s. Throughout the decades campaign life has been increased due to operational practices, technological changes and brick quality improvements. In recent decades the campaign life had been extended such that a complete rebuild was scheduled every 3 years. The latest furnace rebuild and start up has been after a campaign life of nearly 6 years. Brick construction methods and techniques along with furnace operational practices allow the present campaign to be double that of the historical campaign length.

Jan 1, 2007

By P. C. Dagneau

QUEBEC CARTIER MINING COMPANY was incorporated in 1957 to explore and develop low grade iron are deposits in Northeastern Quebec. Four separate deposits were located and identified as being of ore quality and size to support commercial development. Said deposits were located at Lac Jeannine, Mount-Wright, Fire Lake and Mount-Reed. In 1970, in preparation for the replacement of the depleting Lac Jeannine are reserves, construction of an SS-mile railway extension was initiated, towards the newly selected mine site at Mount-Wright. This orebody was selected because the physical and chemical characteristics of the ore were very much similar to those of Lac Jeannine, as well as its huge reserves, estimated at more than one billion tons. In addition to the railroad extension, a mine, concentrator and related facilities were constructed and the new town of Fermont was created. Total investment for the Mount-Wright project exceeded $700 million and initial production commenced in 1976. Quebec Cartier is presently (1992) the leading producer and seller of iron ore in North America at 15,5 million tons and employs some 2,300 people.

Jan 1, 1993

The Anglo Platinum Mogalakwena North concentrator was one of the first three hard rock mineral processing applications to utilise a HPGR circuit in preference to a SAG milling circuit. This was driven by the extreme competence of the ore that had given rise to throughput issues on the original South Plant. Despite more than adequate capacity and performance of the individual comminution units, the circuit has struggled to obtain full design capacity. A thorough review of the integrated performance of the circuit revealed a wide range of bottlenecks and underutilised parts of the circuit arising from design issues. Interestingly, the major opportunities lie in materials handling issues and mismatch of loads about the circuit. This paper presents the high-level outcomes and the associated opportunities, and is pertinent to all HPGR circuit designs.

Jan 1, 2012

By John R. Goode

Barrick Gold Corporation operates gold mines in the United States, Chile, &apos;Peru, Canada, and in the near future, in l1anzania. Barrick meets environmental requirements and limits the potentially adverse effect of cyanide discharge to the environment using various cyanide destruction techniques. Barrick operations use, or have used, natural degradation, ferrous sulphate, hydrogen peroxide, Caro&apos;s acid, alkaline chlorination, and the SO/Air process for cyanide destruction. This paper presents a general discussion of the options for controlling cyanide in plant effluent and provides details of Barrick&apos;s operating experience including general notes on costs.

Jan 1, 1998

By Adrian Molinari

A radioisotope probe (Minexan 202) capable of simultaneously analyzing a mineral slurry for five elements and pulp density has been developed by Outokumpu Oy, Finland. The probe is designed to operate immersed directly in a process stream, or it can be equipped with a flow cell through which passes a continuous sample of the main stream. A minicomputer (PDPII) is used to control the probes and calculate the assay data. This paper describes the probe as applied to slurry analysis and compares it to the conventional x-ray on-stream analyzer (Courier 300).

Jan 1, 1977

By A. Marek

The safe and optimal installation of roof support remains one of the biggest challenges in underground mining today. Traditional hand-held, roofbolt installation in conventional mining has been replaced, in a lot of mining operations, by mechanized equipment. This was a first step to moving the operators out of the unsafe working environment and a start on the trend toward a changed support regime in mechanized mining. However, the challenge of handling of the drill steel itself, as well as inserting resin cartridges and bolts, remains a major hazard and the cause of many lost-time injuries. The paper describes and discusses developments in this area, of mechanized bolting and on-board automation, presenting solutions to known problems, achievements to date, and future developments. The solutions presented will identify with addressing customer needs while touching on possibilities for further technology changes, keeping focus on the safety aspect for operators and the need to bring the operators even further away from the unsafe working environment. The-state-of-the-art technology in mechanized bolting equipment is presented and a brief outlook on the past, current, and future developments is given.

Jan 1, 2012

By J. A. Brusset

THE Greenhill mine of West Canadian Collieries, Limited, is situated at Blairmore, Alberta, and produces 2,500 tons per day of bituminous coal. On Monday, October 25th, 1943, smoke was discovered by a party of firebosses on their regular weekly inspection of air-ways. Probably the fire had been smouldering for several days but, as it had started on the outcrop at the top of an old raise filled with dirt, only a small quantity of smoke could filter through, and the plume of mist that crowns the fan at that season had prevented the fan-man from noticing it. This raise is only about 200 feet from the fan, and is 70 feet long between the fan-drift and the outcrop. It was impossible to prove the origin of the fire, as it had probably started several days before it was discovered, but it is possible that a careless smoker may have thrown a match into the opening at the outcrop, and that the old, dry timber had caught fire. The airways are in No. 2 seam, a bituminous seam 18 to 25 feet thick surmounted by shales and sandstones. Only 45 feet vertically above it is No. 1 seam, 12 feet thick, overlain by a strong conglomerate. In that vicinity, No. 1 seam had been worked out about ten years ago and the strata between the two seams are undoubtedly fissured. The pitch of both seams is 43 degrees.

Jan 1, 1945

By Kelvin K. Wu, George H. Gardner

On July 24, 2002, a nonfatal entrapment accident occurred at the Quecreek #1 Mine, Black Wolf Coal Company, when an active mining section inadvertently cut into a flooded abandoned mine. This incident, and the dramatic rescue which ensued, brought national attention to a common problem in the coal mining industry. Since 1995, there have been more than 100 inundations at coal mines in the United States. Unavailable, inaccurate, or incomplete mapping of older abandoned mines is typically responsible. Serious problems associated with accidental discharges of fluid mine waste material (slurry) and water from coal refuse disposal facilities have resulted from similar causes. Recent problems related to the inaccurate location of old abandoned mine works have increased the interest in the use of conventional and emerging drilling and geophysical techniques for detection of air-filled and water-filled cavities. The United States Congress has committed significant funding toward investigating the applicability of these technologies. MSHA actively promotes the use of the best available technology to minimize the significant adverse safety and environmental consequences associated with unplanned breakthroughs and inundations. This paper provides background information and a general summary of the MSHA-sponsored field demonstration projects which are currently in progress. Potential benefits and limitations are discussed. The need for field verification/ground-truthing is emphasized. Under appropriate conditions, geophysical methods can be effectively integrated into a comprehensive field exploration program.

Jan 1, 2005

By D. Eugene Rannels, Sarah E. Dunsmore

"Dunsmore, Sarah E., and D. Eugene Rannels. Extracellular matrix biology in the lung. Am. J. Physiol. 270 (Lung Cell. Mol. Physiol. 14): L3-L27, 1996.-The lung and other organs are comprised of both cellular and extracellular compartments. Interaction of these components modulates physiological function at the organ, cellular, and subcellular levels. Extracellular components in the gas-exchange region of the lung include both noncellular interstitium and basement membranes. Connective tissue elements of the interstitium in part determine ventilatory function by contributions to tissue compliance and to resistance of the diffusion barrier. The basement membrane underlies cells of both the alveolar epithelium and the capillary endothelium; basement membrane components exert biological effects on adjacent cells through receptormediated interactions. This review emphasizes current knowledge concerning the composition and biological activity of extracellular matrix in the alveolar region of the lung. Matrix synthesis and turnover are also considered. Directions for future research are suggested in the context of current knowledge of the lung and other model systems. EXTRACELLULAR MATRIXEXTRACELLULAR MATRIX is a general term that encompasses components of the basement membrane and interstitial connective tissue. The extracellular matrix has many functions. It provides structural support, compartmentalizes tissues by separating epithelium or endothelium from interstitium, and serves as a physical barrier. Both in vivo and in vitro studies show that extracellular matrices also affect cell shape and function. The matrix elicits a variety of cellular responses, including adhesion and spreading, changes in cytoskeletal organization and differentiation, formation of focal contacts and stress fibers, stimulation of proliferation and migration, induction of polarity and gene expression, alterations in metastatic activity, and outgrowth of cell processes (for review see Refs. 387, 462). Cellmatrix interactions play roles in embryonic development and organogenesis (for review see Refs. 1, 91), in wound healing (for review see Refs. 145, 327), iri metastasis (for review see Refs. 430, 431), and in angiogenesis (for review see Refs. 185, 186). The extracellular matrix is the subject of a large volume of literature. In 1994, over 1,000 articles contained extracellular matrix in the title or abstract. After a brief discussion of key aspects of extracellular matrix biology, this review will focus on the extracellular matrix of the lung."

Jan 1, 1998

By M. G. Beukes

"In South Africa most of the large gold mines operate between 1500m and 4500m below surface where reef is accessed initially through a vertical shaft system then via a network of tunnels and mined in either a longwall, sequential grid or scattered mining configuration. Due to the complexity of the ventilation networks used to ventilate these mines and the potential disastrous consequences associated with underground fires, it is of utmost importance that these mines are managed in such a way that underground fires are prevented. However, if they do occur the fires are managed to firstly prevent the loss of life and secondly protect the infrastructure and viability of the mine. The aim of this paper will be to: • Discuss current SA mining legislation regarding underground fire prevention and control. • Examine these fires from a risk management perspective by means of a bowtie assessment. • List and discuss the major Threats and Consequences as determined by the bowtie assessment. • Discuss the various prevention and consequence controls for deep level underground fires. • Examine how to effectively run an emergency control room. From this, a practical way of designing, implementing and managing an underground fire management system is explored. Lastly, the paper identifies new technology and ways of thinking and how these can be used to combat underground fires. INTRODUCTION The orebodies of South African gold mines are generally narrow tabular structures that vary in thickness between 0.8m and 1.2m with an inclination of between 200 and 700. This, coupled with depths of between 1500m and 4500m, as well as the unpredictable geology, creates unique challenges and significantly impacts on mine designs and mining methods. In general, gold bearing reefs are accessed initially through a vertical shaft system then via a network of tunnels and mined in either a longwall, sequential grid or scattered mining configuration (Figure 1). Mining is very labour intensive with very limited mechanisation opportunities and this increases the risk to human life if an underground fire occurs. On 16 September 1986, one of the worst mining disasters in SA mining history took place when 177 mineworkers were killed at Kinross Mine. An acetylene tank sparked flames that swept through the mining tunnel igniting plastic covering on the wiring and the flames also set fire to polyurethane foam. The burning plastic combined with polyurethane and the toxic fumes that filled the shafts caused the miners death. This incident was a stark reminder of the serious consequence that underground fires can have on human life as well as the crippling financial and asset impact for the mining companies. Over the past thirty years, the SA mining industry reduced the number of mine fires significantly by replacing normal timber support with fire retardant treated timber, alternative support systems such as backfill and elongate support and many other fire prevention initiatives. Although the number of fire incidents and number of fatalities due to fires does not show a direct correlation because of various factors, the controls put in place against fires has had an impact on the number of fire and explosion fatalities (Figure 2)."

Jan 1, 2019

By Oliver C. Ralston

Fluorescence is of growing interest to the mineral industry because certain minerals may be detected thereby and because, as shown in figure 1,4/ many minerals (natural or synthetic) are needed in tubes and lamps. The use of fluorescent lighting is expanding, and large numbers of lamps of many sizes and shapes are being made and used in works, factories, stores, offices, homes, and in photography. Fluorescent tubes, as distinguished from clear tubes filled with neon, argon, or other rare gases through which a current of electricity passes, fluoresce owing to specially, selected and prepared minerals placed in the tubes. Luminous chemicals and paints also contain special minerals and are used in similar applications; therefore, these also will be considered in this report. Although the quantity of minerals (in tons) that are used for fluorescent purposes is small, and probably will continue to be so, this use is significant because it exemplifies a requirement for "pure" minerals in which a trace of contaminant as" minute" as one part in ten million may distinguish between the acceptance or rejection of a particular material. This extreme purity makes synthetic minerals almost essential, and natural mineral&apos;s are now little used.

Jan 1, 1944