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By John C. Edwards

Several experimental programs were conducted at the Pittsburgh Research Center to investigate the level of mine fire detection and alarm capability possible using state-of-the-art technology. These programs involved comparison of the response and alarm time of optical and ionization type smoke sensors to smoldering and flaming coal combustion in a smoke chamber. Coal combustion experiments conducted in the smoke chamber demonstrated that a CO concentration of 5 ppm above ambient corresponded to an optical density of 0.022m1. For the four smoke sensors for which a continuous analog signal was available, a smoke sensor alarm was defined as the average background signal plus ten times the peak-to-peak noise. This alarm criterion resulted in the association of the alarm for three of the four sensors with a smoke optical density of 0.022m-1. and 0.033m-1 for the fourth smoke sensor. The smoke sensors used in the smoke chamber studies were incorporated into large scale diesel fuel fire experiments conducted under normal ventilation conditions in the Safety Research Coal Mine (SRCM) at the Pittsburgh Research Center. These experiments showed that a diffusion mode smoke sensor alarmed earlier than a diffusion mode CO sensor; and, based upon the measurement of the optical transmission at the location of a pump mode ionization type smoke sensor that a pump mode ionization smoke sensor alarmed at an average smoke optical density of 0.021m" for the twelve experiments conducted. A series of 30 and 330 kW diesel fuel fire intensity experiments were conducted under zero airflow conditions in the SRCM. It was determined that :(I) thermal sensors are inadequate at 30 m from a 300 kW fire;(2) a diffusion mode ionization smoke sensor can be more effective for mine fire detection than a diffusion mode CO sensor;(3) recommendations can be made for sensor spacing in a mine entry based upon the measured CO buoyancy induced spread rates along the mine roof and the time for a developing coal fire to ignite a conveyor belt.

By Lucas Lopes da Costa

Bamboo fibers were characterized in terms of diameter distribution and tensile properties. Polyester matrix composites reinforced with these fibers were investigated for their flexural mechanical behavior. Specimens with up to 30% in volume of continuous and aligned bamboo fiber composites were bend-tested until fracture. The results showed an improvement in the composite strength and stiffness with the amount of bamboo fiber. A microstructure analysis by scanning electron microscopy revealed a reasonable adhesion between the fiber and the polyester matrix which justifies the improved mechanical properties of the composites.

Jan 1, 2010

By O. P. Chisholm

Dross emerges from the blast furnace either with the lead through a lead well or by tapping from a forehearth or settler, but until a dozen years or so ago few dross reverberatories were used in western lead smelters because it was the usual procedure to circulate the dross from the drossing lead kettles back to the blast furnace. It was quite customary for lead smelters to produce matte in their blast furnaces, as this was the form in which copper could be collected, concentrated if necessary, and shipped to the copper smelters for further treatment. The main prerequisites for good matte formation arc., of course, a more or less definite amount of copper on the charge and sufficient sulphur. Such troublesome impurities as arsenic and antimony were ignored, in so far as possible, although they contaminated the bullion and thereby increased refinery costs. At the same time stocks of blastfurnace speiss containing gold, silver, lead and copper in addition to iron, arsenic and antimony, were being accumulated for want of a market to absorb them. As the dross was being fed back to the furnaces as rapidly as it was being produced, arsenic and antimony tended to build up until the arsenic could effect a combination with copper and iron and an alliance with lead, and the antimony a combination with copper and an alliancc with lead. Sulphur, being the most active agent in taking up the copper, left little of that element for the arsenic and antimony, so that on the whole a somewhat unsatisfactory metallurgy resulted. During this same period, certain lead plants were beginning to encounter trouble with zinc due to the replacement of crude ores of lot zinc content by concentrates containing high percentages of lead and zinc in sulphide form, the blast-furnace slags resulting from the smelting of such concentrates being characterized by a decidedly increased zinc content. It was soon realized that zinc plus sulphur was "poison" to a lead blast furnace and steps were taken to reduce the sulphur content,. At this stage some plants found that any substantial matte fall was out.

Jan 1, 1937

Jan 1, 1969

By Jock A. Campbell

Oil-impregnated rocks are known to occur in 22 of the 50 states. The largest known petroleum resources of this type are in Utah, with over 95% of the inventoried total, The Utah deposits are estimated to contain over 25 million bbl (42 gal per bbl) of oil in place.' All major Utah tar sand deposits crop out and can be mined partially by open pit methods, but in-situ techniques will have to be employed to recover oil from the deeper parts of the deposits. No significant development of Utah tar sands deposits for their petroleum content has occurred to date, although a mine and extraction plant are anticipated this year at Asphalt Ridge. The barriers to development have been mainly economic, but technological and legal problems will also have to be overcome.

Jan 5, 1975

Alternative processes for converting coal to liquid products and their stage of development are outlined. The merits of hydrogenationprocesses in general, and the solvent refined coal process in particular, are stressed. Bench scale experimental hydrogenation procedures used by the Australian Coal Industry Research Laboratories Ltd. (ACIRL) to study the liquefaction of Australian coals and correlations between properties of such coals and their conversion to liquid products are described. Factors involved in assessing investment and operating costs for modern hydrogenation based coal refineries of different capacities are described with reference to a recent study undertaken in N.S.W. The significance of coal properties such as yield and yield structure of total liquid products and how they and other factors can influence the economics of the coal refining operations are discussed.

Jan 1, 1977

William Andrews Clark, former United States senator from Montana, died at his home in New York on March 2, at the age of 86, after a brief illness due to pneumonia. He was the last of the three great Montana mining magnates, Clark, Daly and Heinze. He was born in Connellsville, Pa., on Jan. 8, 1839, and in 1863 arrived in Bannock, Ida., with only five dollars, after a journey of 65 days. On reaching Idaho, he became successively a miner, teamster, machinist, railway builder, mine owner, capitalist and, in his more recent years, philanthropist and art collector.

Jan 1, 1925

By Shawn Downey

A helical pile with in-situ grouted shaft was used to underpin the existing slab of a large retail store in the Edmonton, Alberta Canada area. The existing structural slab did not have the capacity to support the increased load requirements. The design to upgrade the capacity specified a drilled shaft as the deep foundation to underpin a portion of the slab. A helical pile was quoted as an alternate and ultimately won the bid based on the advantages of the system. After an ASTM D1143 Quick Load Test confirmed the axial compression capacity, 723 helical piles with grouted shafts were installed in 3 weeks underpinning 40% of the 93,000 ft2 (8,660 m2) building.

Jan 1, 2003

By S. Zamna, M. E. Defoe, Franklin T. Davis, Earl Rau, Yarroll. Warren H., Paul D. Chamberlin

This section contains a description of the ore processing methods of the walled industrial minerals that are not described in major sections of the book. Table I contains the production figures for each of these commodities in the United States and the world. Specifications for concentrates or final mineral product are also summarized as well as prim for them at the time the section was written. In each chapter an attempt has been made to provide the reader with information on the common commercial mineral or minerals involved with the commodity, some of the uses. the processes used to recover and concentrate the minerals, as well as geographical areas where these process are utilized.

Jan 1, 1985

By Gordon King

This paper presents a case study of large diameter continuous flight auger (CFA) piles and drilled shafts utilized for foundation support of a series of heavily loaded cement plant structures at the Suwannee American Cement (SAC) Plant in Branford, Florida. The high loads and exacting total and differential settlement criteria when combined with a highly variable subsurface geology provided a challenging design scenario. Fully instrumented static pile load tests were performed to determine design parameters in the variable weathered limestone bedrock. Ultimate side friction values ranged from 2 to 8 tsf within the limestone, resulting in the requirement for CFA piles up to one meter (approximately 40 inches) in diameter and socket lengths of up to 40 feet. At several localized areas, the limestone bedrock was in excess of 60 feet below grade, requiring the use of cased drilled shafts to depths on the order of 80 to 90 feet. An integral part of the production pile installation was the use of instrumentation to monitor drilling and concreting parameters. Calibration of drill rates, torque and auger rotation with rock quality was performed to allow monitoring of the soil stratigraphy at each pile location. When combined with the results of the instrumented load testing, the monitoring of drilling parameters allowed confirmation that sufficient socket length was achieved within the quality of rock present at each and every pile location.

Jan 1, 2003

By William McFerren, Pragasen Moodley

In contrast to global trends, African, especially South African, surface mining operations have shown a significant rate of adoption of Electronic Detonators (ED’s) over the last few years. Proven benefits of converting to ED’s from pyrotechnic initiation systems have aided this market conversion. These benefits are experienced throughout the mining operation. Benchmarking exercises, prior to the introduction of ED’s, form part of the conversion process and allow for quantifying improvements. Extensive work has been done on quantifying the benefits of converting to ED’s and have shown that results can be reproducible. Improvements have been experienced in many applications and include environmental impact control, improved mining efficiencies, increased cast benefit and improved size distribution. These step changes in blasting results, in conjunction with the adoption of ED technology have aided the rapid conversion of the African surface market.

Jan 1, 2004

By B. Van Voorhis

Successive changes have been made in stoping methods at the Magma mine. Factors that have made these changes advisable are: vein width, heavy and swelling wall rock, abnormal rock temperatures, ventilation, labor costs, timber costs, mining speed, and labor-saving mechanical developments. Additional localized conditions, such as low angle post-mineral faulting and selective mining, have also made changes necessary. A stoping method with enough flexibility to meet most of these conditions has been in use for the past ten years. The Magma Copper Co. was organized by the late William Boyce Thompson in 1910 and acquired by purchase and location several groups of contiguous claims, among them the Silver Queen property. The Hub and Irene claims acquired in this purchase cover the apex of the vein, and all stoping done up to 1920 was from these two claims

Aug 1, 1956

By I. Iwasaki, R. H. Heerema

The presence of calcium and magnesium ions in iron ore pulps that are upgraded by selective desliming can result in indiscriminate flocculation of both iron oxide and siliceous gangue slimes. The removal of these alkaline earth cations in pulp solutions by chemical precipitation was ineffective as a means of deflocculation of quartz. It was shown by using various techniques (electron micrographs, abstraction, and streaming potential measurements, and cationic flotation tests) that heterocoagulation between the precipitates [Mg(OH)2, hydroxyapatite, and CaCO3] and quartz particles was the reason behind that observation. In addition, the precipitates adversely affected the recovery of quartz by cationic flotation, due to slime coating, a case of heterocoagulation. Magnesium hydroxide produced a uniform layer of coating across the quartz surface, while hydroxyapatite and calcite produced discrete, localized deposits dotting the surface.

Jan 1, 1981

By N. Aydogan, H. Dundar, Å. Partapuoli, A. Fredriksson, P. Wikström, K. Tano, G. Adolfsson

The Autogenous milling of ores holds an increasing attraction as the focus moves towards reducing energy usage, both direct and embodied in grinding media. However, most of the early AG mills were converted to SAG for improved stability and increased throughput. This imposes a huge penalty in steel grinding media consumption. The LKAB iron ore operations in Sweden process highgrade magnetite through fully-autogenous milling lines to a final product P80 of about 45µm. The outcomes of P9O AMIRA research surveys, covering a wide range of mill fillings and throughputs and with different feed blends, are presented. Insights are provided on operational strategies, opportunities, the influence of feed size control and balancing the blend of competent gangue and softer magnetite. Areas of importance in the successful operation and control of energy-efficient autogenous circuits are highlighted.

Jan 1, 2012

By Anne Lemnitzer

Full-Scale cyclic field testing was performed on a 3x3 pile group consisting of nine cast-in-drilled-hole (CIDH) reinforced concrete shafts and a comparable single-shaft in order to investigate group interaction effects, derive p-y curves for reinforced concrete fixed head piles and to validate currently available p-multiplier models. The piles are identical in diameter of d=2 ft and were tested in similar soil conditions. The single pile as well as in three piles within the pile group were instrumented with internal sensor instrumentation to record pile curvatures. External instrumentation was used to control and measure the lateral displacement of the specimens. Experimental studies were supported with analytical models to enable comparisons and offer design recommendations. All test specimens were tested to structural failure and group interaction factors ranged between 0.8 at small displacement levels and increased towards unit near structural failure. A set of p-multipliers was found to reproduce an accurate fit to the available test data.

Jan 1, 2010

By Asa Weber

With continuing pressure from stockholders not only to maintain but to increase mineral revenues, producers have increased plant capacity. Depressed mineral prices have accentuated the trend toward higher production rates to maintain consistent cash flow, and these same trends have promoted the development of large-scale processing equipment. In addition to the need to handle increased throughput, larger flotation equipment can result in decreased capital-equipment and operating costs. The development of larger column and conventional flotation equipment relies, in part, on suitable scale-up procedures. To properly scale-up large flotation cells and columns, certain constraints and design parameters must be taken into consideration, including velocities in the vessel, residence time, solids suspension, and lip loading. This paper will review the design constraints and scale-up criteria for WEMCO® flotation cells. Scale-up criteria are augmented with computational-fluid- dynamics analyses and high-speed imaging techniques, as well as multiple regresesion analysis of in-plant operational data.

Jan 1, 1999

By L O. ÆNeill, J Bebek

When Kalgoorlie Consolidated Gold Mines (KCGM) purchased its fleet of 18 CaterpillarÆs dump trucks in 1999, as part of its change to owner operated mining, five CaterpillarÆs Computer Aided Earthmoving Systems (CAES) were also commissioned on Komatsu PC8000 hydraulic shovels and Caterpillar D10R bulldozers. Since then the CAES system has been installed and operational on Komatsu PC3000 hydraulic shovel, CaterpillarÆs D10R dozers and Cat 994 front-end loader while Cat 854 wheel dozer has been fitted with CAESbasic. This investment in advanced machine guidance and control technology has proven very beneficial over the years for the Super Pit with improved safety and increased operating efficiency and productivity. The paper brings into focus how the CAES system adaptation in unique mining conditions assists in production gain, equipment operatorÆs safety, flexibility and independence, personnel removal from hazardous areas, acquisition of operational information and improvements in mine planning and design, benefiting the entire mining operation.

Jan 1, 2003

By Wang SS, Frattaroll DR

In the development of novel sulfide collectors, especially for the low-lime and acid circuits, flotation of chalcopyrite, chalcocite, covellite and pyrite was studied with both new and commercially available S- containing collectors. The natural float- ability of sulfides, water quality, and redox potentials - all of which were considered im- portant in assessing collector strength and selectivity - were also investigated. Chalcopyrite exhibited the highest natural floatability. The response to most collectors, however, was chalcocite > covellite > chalcopyrite > pyrite. Water quality had a very significant effect on both natural and collector-aided floatability. De- ionized water and tap water had a flotation suppression effect compared with doubly- distilled water. Flotation results with single minerals are correlated with those for copper and pyrite from natural ores. Several novel collectors have now been developed for sulfide flotation in acid, neutral or mildly alkaline circuits. The results for four of these collectors, which have shown promise in commercial applications, are discussed in this paper.

Jan 1, 1986

By A. V. Tarasov

In order to improve technical, economic and environmental performance of hydrometallurgical processing of intermediate products containing copper and nickel, the Gintsvetmet Institute and the IMET Institute of the Russian Academy of Sciences have conducted studies into the efficiency of the use of alternating current of industrial frequency on processes applied for hydrochemical leaching of various copper- and nickel-containing materials. It has been found that: 1.Imposition of alternating current over the process of leaching of softly reduced nickel oxide with recycled copper sulfate solutions resulted in an increase by 20 to 30% of the rate of the copper cementation process and reduced by 20% its activation energy. At the same time, the recoveries of nickel, cobalt and iron to the leach solution increased up to 82.2%, 78.5% and 57.1%, respectively, and that of copper to the cement precipitate up to 74%. Optimal process conditions have been identified with respect to the current density, electrode material, copper concentration in solutions and the process temperature. 2.In the process of hydroelectrochemical sulfuric acid leaching of nickel and copper sulfides, the grain size, the phase form of sulfides, the solution composition (H2SO4, Cl?, Cu2+, Fe3+)and the current amperage had an effect on the nickel recovery to the solution, which reached 90%, while the degree of copper transfer to solution did not exceed 20%. The process of hydroelectrochemical sulfuric acid leaching of nickel and copper sulfides with an addition of Cl? made it possible to selectively recover nickel into the leach solution along with concentrating copper in the leach residue. 3.When subjecting samples of commercial-grade magnetic fractions of converter matte to sulfuric acid leaching, the imposition of electric current, the concentrations of sulfuric acid and chloride ion in the solution and the duration of the reaction process had an effect on the process. The nickel recovery was 85% and that of cobalt and iron was 95% and the recoveries reached 97.5%, 98.3% and 99.8% as a result of repeated treatment of the primary residue under similar process conditions. Up to 75% of copper, 75% of sulfur and 99.0-99.5% of palladium was concentrated in the solid reach residues. The experimental data obtained indicates that the use of AC for hydroelectrochemical sulfuric acid leaching for separation of copper- and nickel-containing intermediate products has favorable prospects.

Jan 1, 2003

By Sigvard Eklund

El presente trabajo analiza los datos recogidos en la memoria del Organismo Internacional de Energía Atómica con el propósito de vislumbrar los acontecimientos que se producirán en el campo de la energía nucleoeléctrica durante el decenio que acaba de comenzar. Con la palabra "desafío" se subraya las posibilidades que entraña la energía nuclear para contribuir a la solución de los problemas energéticos del mundo.

Jul 1, 1983