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Several major impediments threaten the successful delivery of tunnel and under-ground construction projects. In addition to technical design and construction risks associated with tunnel projects, many of which are well understood, budgetary pressures, funding constraints and the complexity of procuring, administering and executing multiple concur-rent projects in a large program could also have a catastrophic impact on the program?s objectives. Contributing factors often include poorly managed design, procurement, construction, managerial, organizational, market and stake-holder risks, as well as nonconforming inputs or outputs to the costs and schedule, or any other potential inabilities to deliver the required or desired results. A strategy to prevent ?failure? of a project requires a proactive and holistic approach to risk management. Through planning, identification, analysis, management, monitoring and control of the project?s risks (both threats and opportunities), attention to management of risk will in-crease the probability and impact of positive events and decrease the probability and impact of events adverse to a project?s objectives.

Fossil fuel consumption in the United States increased markedly over recent years, and future demands expect to be even greater. Coal, this Nation's most plentiful natural fossil fuel, will play a key role in fulfilling these demands. With expectations of increased coal exploitation, the U. S. Bureau of Mines authorized this project, the objectives of whi.ch were to prepare an authoritative report on current surface coal mining technology, to define current problems and possible solutions, and to project future developments necessary to assure adequate surfaced mined coal production to meet the Nation's future energy needs. These objectives we're accomplished by an extensive review of available published literature and data gathering field visits to active surface coal mines throughout the country.

Jan 1, 1975

By G. C. Mackenzie

At the last Annual Meeting of the Institute, Dr. C. V. Corless sketched the potential mineral wealth of Canada so clearly, graphically and with-all so entertainingly that one's imagination was fired with the promise held out to future generations for the tremendous expansion of the mining industry in the Dominion. Posterity will undoubtedly witness the fruit of much of the geographical search and survey that is now carried on by our government mining departments. Year after year the work advances, slowly but surely, new areas are . explored, older areas are surveyed in detail, the information being compiled in maps and reports of incalculable value to the prospector, the engineer and the general public. The immensity of the task of exploring, geologically, the outlying portions of the country, with the ultimate view of making valuable mineral discoveries, may be visualized from a study of Dr. Corless' paper and the subsequent discussion which took place and one becomes impressed with the fact that three-quarters or more of the problem can be included under the word "transportation". For instance Dr. Corless said, "The few geological explorers who have penetrated to these remoter regions . . . . . . have as a rule been compelled to stick closely to canoe routes,"; Dr. Goodwin remarked, "This barren Laurentian granite, which is put down on the maps as covering the greater part of this area, is the best guess the geologist could make from travelling along watercourses Within the next few years . . . . . . the Timiskaming and Northern Ontario railway will undoubtedly be extended to James Bay . . . . . . In order that we may be prepared for the probable influx of prospectors when transportation facilities to tidewater are provided, I think all available information on this district should be gathered together in handy form." All three-Corless, Goodwin and Cole-emphasize the well-known fact that explorers, geologists and prospectors working in new country must stick to the watercourses and that transportation by rail, road or water has always been the all-important deciding factor in facilitating the exploration and development of remote districts. Dr. Corless did, however, suggest other means of transportation in stating, "The aeroplane will be of assistance in future study of some parts of these remote areas."

Jan 1, 1924

By Thomas Lane Carter

THE history of mining in South Africa differs somewhat from that of other countries in the part taken by the aborigines in the development ?of the mineral deposits. The Spaniards in America, and the fortune-seekers of Australia and New Zealand, found large numbers of natives in these new countries, but the inhabitants did not become willing or efficient workers ill the mines which the white men started. The Kaffirs of South. Africa have not shown the same antipathy to labor, nor do they show any signs of dying out in the presence of the white man's civilization. They are a virile race, and so far the vices of civilization have not killed. them. While it is true that the brain and skill necessary for the exploitation of the mineral resources of this sub-continent-have been supplied by the white race, it is also a fact that most of the rough labor in the development of the mining industry of South Africa has been done by the Kaffirs. The Kaffir tribes differ greatly in their mental and physical capabilities. Compare, for instance, a Zulu of Natal with a Bechuana, or a Xosa of Cape Colony with some of the degenerate tribes of Central or East Africa, and you will find that they have little in common, save that their skin is black and that they do not believe in clothes. As a general rule, the tribe's in the milder, healthier climates are far superior, both in mind and body, to the Kaffirs brought up in the hot malarial sections of Central Africa; and it naturally follows that the black men from the temperate zones of the country, are much finer workmen than the degenerates from less favorable sections: It is universal in South Africa to speak. of the .Kaffirs as " boys." No matter if he is 90 years old, the Kaffir is always a " boy," and in this paper the word " boy " is synonymous with Kaffir.

Nov 1, 1908

By J. J. S. Sebastian

The process development described in this report was carried out at the Morgantown Station of the U. S. Bureau of Mines in cooperation with West Virginia University. An experimental laboratory-scale pilot unit to gasify coal dust in entrainment was constructed on the Campus of the University in Morgantown. The enormously accelerated demand for liquid and gaseous fuels and utilization of our immense coal resources require that a low-cost process be developed for the gasification of a wide variety of coals. Such a process would be a major factor in lowering the cost of synthetic liquid fuels. None of the proc3sses developed in Germany prior to and during World War II, such as the Winkler process, the H. Koppers dust gasification process, the Wintershall-Schmalfoldt process, etc., meet all the requirements for a low-cost process under American conditions. Nor has any other process designed and experimentally operated at atmospheric pressure during the post-war period in this country appeared to fulfill all of the necessary conditions for a low-cost process.

Jan 1, 1950

By Ladislao J. Prazak

El texto describe cuál es el planeamiento de la higiene industrial en la planta de peletización de Marcona Mining Co. Para esta labor, se debe evaluar el tipo de trabajo de la máquina, funcionamiento técnico y los materiales usados. En base a estos datos conocidos, se determina los riesgos inherentes en la producción, como de los riesgos profesionales inmediatos. La función primordial del programa de higiene industrial estriba en la formación somática, mental y emocional del trabajador para asegurar el lugar de ubicación donde este puede desarrollarse mejor, evitando arriesgar la integridad física del trabajador como de sus compañeros. Finalmente, se indica las reglas higiénicas generales como el ambiente higiénico de las horas libres del trabajador y su familia.

Aug 20, 1963

By S. Banisi, E. Arghavani, Gh. Parsapour, S. Mousavi

Maximization of water recovery in thickeners is an essential step in the mineral processing industries. The Gol-E-Gohar iorn ore processing plant uses a center pier thickener with a diameter of 38 m and depth of 4 m. The feed rate is 50 t/h solids with a concentration of 5% (w/w), and it has been designed to provide an underflow containing 50% solids. The performance of the thickener was not as expected judged by the overflow stream containing 0.6% solids and water loss of 52 m3/h in the underflow. A criterion called the index of flocculation incorporating the perimeter-based fractal dimension of flocs, floc size, and settling velocities was proposed and used to determine the optimum flocculant dosage which was found to be 20 g/t. The fractal dimension of flocs in a pulp containing 5% solids was found to be between 1.16 (no flocculant) and 1.56 (40 g/t flocculant) which indicated highly branched and loosely bound structures for the flocs as flocculant dosage increased. At these conditions, the size of the flocs which was recorded by a digital microscope increased from 93 µm to 403 µm. A new feedwell with a special design with the aim of preventing flocs breakage and maximizing energy dissipation of pulp was constructed and installed. These modifications led to an increase in the thickener drivehead torque from 5% to 18% of the rated torque, indicating a higher bed depth. Finally, installation of a PID controller reduced the drivehead torque relative oscillation from 52.0% to 12.7%. These changes increased the solids concentration of the underflow from 49.0% to 56.9%, decreased the overflow solids concentration from 0.6 % to values smaller than 0.01% and resulted in a reduction of 27% in water loss in the thickener underflow.

Jan 1, 2014

By Marc. A. Meyers

The analysis of the phenomena involved in the determination of the compressive strength of iron-ore agglomerates leads to the identification of the important parameters. It is shown mathematically that the pellet rupture strength is proportional to the cross-sectional area. Fracture is initiated at the center of the pellets by the tensile stresses developed by the compressive loads normally to the compression axis. The variation in strength between individual pellets of identical composition and subjected to identical treatments is due to internal voids of varying sizes, that act as stress-concentration sites. Two novel testing procedures are proposed. The first consists of testing the pellets between two plates having three steel spheres each. This configuration simulates much better the environment actually encountered by the pellets. The second procedure consists of a thick-walled cylinder in which a piston penetrates; a large group of pellets is tested simultaneously, as the stress versus strain plot is being recorded. This latter test presents significant advantages over the conventional testing procedure; the main one is that one single test is sufficient to characterize the mechanical response of the pellets.

Jan 1, 1981

By Pat Turner, Abrie Schutte, Tim Olson, Roman van Ommen

The key to good cyclone circuit design and operation in primary grinding circuits will be discussed. Cyclone circuit design issues include individual cyclone design features such as cone angle or materials of construction, as well as orientation and manifold configuration. Cyclone performance issues as well as maintenance considerations will be detailed in an effort to achieve consistent cyclone operation with minimal coarse solids in the overflow. The new gMAXTM. cyclones will be introduced and evaluated using operating circuit data in closed circuit grinding applications

Jan 1, 2003

By Shannon Seitz, Qingwen Shi, Junfeng Pan, Shuwen Wang, Brijes Mishra, Shaohong Liu

Delayed coal bursts in deep coal mines have caused significant fatalities and economic losses in recent years. Instead of occurring right around the advancing face, this particular type of coal burst is characterized by its occurrence at a certain distance behind the advancing face. To better understand the mechanism of a delayed coal burst, we used borehole camera, electromagnetic CT, and borehole deformation monitoring device to observe the fracturing and deformation process of an advancing entry’s surrounding coal in the field. Borehole camera detection showed a zonal disintegration phenomenon in the advancing entry’s surrounding coal. Electromagnetic CT detection showed that zonal disintegration developed within 14 days of excavation. Borehole deformation monitoring indicated a deformation rate difference between the intact zone and fractured zones. The deformation rate difference was observed to increase with time and cause increasing elastic energy accumulation in the intact zone. The cumulative elastic energy in the intact zone finally caused a delayed coal burst in the entry. Sensitivity analysis of the cumulative elastic energy was conducted based on a thick-walled model deduced from field detection. The model shows that the smaller thickness of the intact zone brings higher elastic energy in the intact zone. This investigation provides an improved understanding of delayed coal bursts in deep coal mines.

Oct 19, 2021

By V. Rajaram

The oil shales located in the Appalachian Basin cover an eight-state area of the eastern U. S., and are referred to as Devonian (black) shales. These shales have been exploited for their gas potential for several years. The Institute of Gas Technology (IGT) has conducted research since 1972 on the production of shale oil from the Devonian shales, and this resulted in the development of the HYTORT process. This process demonstrated that the yield from the Eastern oil shales can be greater than the value indicated by the Fischer assay method. IGT estimates that 423 billion barrels (67.3 x 109 m3) of oil could be recoverd by HYTORT processing of surface-minable eastern U. S. shales. Recently American Syncrude Corporation and Southern Pacific Petroleum N. L. have proposed oil shale projects in Kentucky. This paper will describe the surface mining and retorting techniques that have been studied for exploitation of the Devonian shales, and enumerate the problems that have to be overcome before commercial production can be realized from these shales.

Jan 1, 1983

By J. B. Cheung

The results of a program to demonstrate the technical feasibility of hydraulic borehole coal mining are presented in this report. The hydraulic borehole method of coal mining involves inserting a hydraulic mining device into a borehole that has been drilled from the surface into the underground coal bed. The borehole mining device issues a jet of water under high pressure, which breaks the coal. These pieces of coal, along with the water, form a slurry, which flows to the base of the borehole where it is pumped to the -surface. Phase I of the program encompassed the design, fabrication and factory-testing of a hydraulic borehole mining device. The program was successfully completed with the field tests being conducted at the Wilkeson-Carbonado Coal Field near Wilkeson, Washington. The technical feasibility of hydraulic borehole coal mining was demonstrated by mining 32 tons of coal at a depth of about 75 ft over a period of 4 hours.

Jan 1, 1976

By C. C. Merrill

Columbium, tantalum, titanium, and zirconium are present in solid waste products generated by the chlorination of rutile used for production of titanium tetrachloride (TiC14). The columbium and tantalum were separated from titanium and zirconium by liquid-liquid extraction techniques using a secondary amine. Salts of these elements are in a leach liquor produced by water leaching of mineral waste from the chlorination of rutile. This waste, produced at the rate of approximately 50,000 tons per year, is about 40 wt pct water soluble. Leach liquors, separated by filtration, were further separated into a solid fraction and a liquid fraction by pressure hydrolysis, The solid fraction containing Cb, Ta, Ti, and Zr was dissolved in HC1-HF and used as a feed solution. Columbium and tantalum were removed from the organic extractant with 1 [N] HC1. A miniature 10-stage reactor showed that the columbium and tantalum present in solution could be separated with a continuous flow.

Jan 1, 1972

By J. F. Henderson

"IntroductionTHE National Advisory Committee on Research in the Geological Sciences was set up by the Privy Council of Canada in 1949. It was set up because you, the Geology Division of the Canadian Institute of Mining and Metallurgy, asked that it be set up. The Committee is, therefore, to a consider-able degree, your offspring. In the role of good parents you, of the Geological Division of the C.I.M., should be interested in the progress of your progeny. How is the Committee organized? What has it recommended? What has it accomplished? On behalf of the National Advisory Committee, that is what I want to tell you about this afternoon.HistoryYou will remember that, in 1946, the Geology Division of the C.I.M. set up a Committee on Geological Research. This Committee, under the Chairmanship of Dr. J. E. HAWLEY, found ""that there is no national organization interested in surveying, co-ordinating, and implementing with financial help, fundamental and much needed geological research. Accordingly, the first and most necessary step to put the geological sciences in Canada on a proper footing .is the recommendation that a National Advisory Committee on Research in the Geological Sciences be formed"" (l).This recommendation was endorsed •by the President and Council of the C.I.M. in 1947 and submitted to the Minister of Mines and Resources."

Jan 1, 1952

By V. A. Marple, K. L. Rubow, B. A. Olson

"A virtual impactor personal aerosol sampler (VIPAS) bas been developed for use in diesel-equipped mines to collect size-separated samples or diesel exhaust and mine dust particles in the respirable size range. This sampler consists or three stages: a 10-mm cyclone, a 0.8- µm cutpoint virtual impactor and two filter cassettes. The large non-respirable particles are removed in a 10-mm cyclone. The respirable particles from the cyclone pass through a 0.8- µm cutpoint virtual impactor with the particles larger than and smaller than 0.8 JI.ID (mine dust and diesel exhaust particles, respectively) collected on two 37-mm filter cassettes. The sampling How rate is 2 L/min so as to be compatible with the standard respirable dust sampler and personal sampling pumps. INTRODUCTIONThe mining industry has been increasing its use of diesel-powered equipment in underground mines, especially in coal mines. With this increased usage has come an increased concern regarding the health effects associated with inhaling diesel exhaust particles since they are in the respirable particulate size range. A Mine Safety and Health Administration (MSHA) advisory committee directed MSHA to develop a sampling protocol for diesel exhaust particles to assess worker exposure (MSHA, 1988). In addition, the National Institute for Occupational Safety and Health (NIOSH) has recommended that ""whole diesel exhaust be regarded as a potential occupational carcinogen as defined in the Cancer Policy of Occupational Safety and Health Administration"" (NIOSH, 1988).Past work, with cascade impactors in both the laboratory and in underground coal mine studies, has shown that the diesel exhaust particles are primarily in the less than 0.8 µm aerodynamic diameter size range whereas the coal dust particles are primarily greater than 0.8 µm (Marple et al., 1986; Cantrell, 1987; Rubow and Marple, 1988; Rubow et al., 1990a, b; Cantrell and Rubow, 1991). This work has been jointly performed by the University of Minnesota and Bureau of Mines researchers over the last 8 years. Typical particle size distributions for a diesel-equipped coal mine and an all electric coal mine are shown in Figure l. Note that the particles in the < 0.8-µ.m mode are the diesel exhaust particles (seen only in diesel-powered mines) and the particles in the > 0.8-µ.m mode are coal particles (seen in both the electric-powered and diesel-powered coal mines). Chemical mass balance analysis was also performed on these two size fractions to determine the degree of particle cross-contamination in the two modes. This analysis showed less than 10% cross-contamination, i.e., in coal mines Jess than 10% of the diesel exhaust particulate was collected in the coarse fraction and Jess than 10% of the mine dust was collected in the fine fraction (Cantrell, 1987; Rubow et al., 1990a)."

Dec 1, 1996

By C. O’Hara, S. Roy, K. Swedburg, J. Katchen

"New Gold Inc.’s New Afton concentrator commenced operation in June 2012, producing a copper-gold-silver concentrate. During the first two years of operation, various optimization efforts have improved mill throughput, recoveries and concentrate grade. Daily mill throughput has increased 20% above the design rate. This was achieved through more consistent instantaneous feed rate and size distribution from the mine reclaim stockpile, higher pebble crusher reliability, changes to the SAG and ball mill grinding media sizes, larger SAG grate openings, reduced SAG discharge screen-deck aperture size and an increase in the maximum ball mill power draw limit. Metal recoveries at New Afton are primarily limited by liberation in the coarser size fractions; therefore, improving the grind size at a given mill throughput has been the main means of improving recovery. The average rougher flotation feed F80 size was reduced from 175µm in Q1 2013 to 165µm in Q1 2014, while the average operating mill throughput increased by 25%. Other flotation circuit changes focusing on recovery improvement include the addition of froth crowders to the rougher cells and the use of a stronger frother. The average concentrate grade increased from 22% Cu in Q1 2013 to 25% Cu in Q1 2014. This was achieved by redirecting the flash flotation concentrate stream to the regrind circuit and by the addition of lime to the cleaner circuit.This paper describes the above improvements made at the New Afton mill. The paper describes the objectives, timing and end result of each area of improvement.IntroductionThe New Afton Mine is situated approximately 10km west of Kamloops, British Columbia, 340km north-east of Vancouver. The mine has a moderate climate, access to transportation and electrical infrastructure, nearby fresh water supply, and close proximity to industrial and mining service businesses. The population of Kamloops is around 90,000 with most mine employees living in or around the city."

Jan 1, 2015

By Robert Hopler

THE work that is being done by the Government to reduce the dangers of mining was brought out strikingly in the First National Mine-Safety Demonstration which occurred at Pittsburgh, Pa., on October 30th and 31st, under the auspices of the United States Bureau of Mines with the assistance of the American National Red Cross Society and the Pittsburgh Coal Operators’ Association.

Jan 1, 2012

By Lewis C. Karrick

In studying the destructive distillation or pyrolysis of oil shales, the primary consideration is to determine the effects of heat on the organic components of the shale. The impracticability of separating these organic components, collectively known as "kerogen", from the mineral matter with which they are associated renders the problem extremely complex. The behavior of the kerogan in the shale while undergoing the heating process is probably different from that of the same kerogen if it could be isolated and treated under similar temperature conditions, and in fact the results of actual distillations have shown that the physical properties of the mineral matter in the shale may be the cause of much variation in the products of retorting. It must be remembered that the inorganic .material of the shale is a heterogeneous mixture of minerals solidified into a very close-grained compact mass. This mineral mass has a thermal conductivity different from that of the kerogen, thus complicating the problem of even distribution of heat. Furthermore, the temperatures of dehydration of gypsum end some; hydrous silicates are included within the temperature range of the shale distillation, These minerals are frequently present in the shales; and the evolution of water vapors from them will affect the partial pressures of the hydrocarbon vapors evolved from the kerogen, probably tending toward, the improvement of the quality of the oil distillates. Carbonates and sulphides which are also frequently present begin to decompose within this range of temperature, and the gases produced from them may alter the chemical constitution of the oils produced from the kerogen.

Jan 1, 1922

By J. B. Mitchell

Using digital image correlation the evolution of strain and strain at the onset of localisation resulting in a hot tear has been determined for alloys AA6111 and Al¬0.5wt% Cu during solidification. High resolution images of hot tear formation and growth were captured during a constrained bar test that incorporated a glass window above a central hot spot region. The images were analysed using digital image correlation software to measure the evolution of displacement and strain based on tracking the motion of discrete features on the as-cast surface of the sample. Temperature data was also acquired with a thermocouple cast into the sample in close proximity to the hot tear. The interval starting from the point immediately after solidification shrinkage ends (the metal pulls away from the glass) and finishing when the first sign of a crack or hot tear is visible to the eye was used to determine strain data. The minimum strain at which strain localisation occurs was found to be 0.0069 in AA6111 and 0.0021 for A1-0.5%Cu.

Jan 1, 2007

By Z. R. Llanos

The petroleum refining industry makes extensive use of catalysts for the conversion of crude oils into more usable products such as gasoline, fuel oil and gas, aromatics, and others. Catalysts used for hydraprocessing contain cobalt-molybdenum or nickel -molybdenum, although there are catalysts that also contain tungsten. During hydroprocessing, nickel and vanadium are deposited on the catalysts, eventually rendering them inactive. The refiners are then confronted with the problem of disposing the spent catalysts. In the past, landfilling was a common method of disposal and it is still practiced in some countries. Other refiners prefer to stockpile the spent catalysts at the refineries until the price of metals warrants their sale to metal reclaimers. This practice, however, poses environmental problems to the refineries for storage and disposal of spent catalysts. Other types of catalysts are amenable to regeneration. The purpose of this paper is to focus attention on the recovery of nickel, cobalt, molybdenum, vanadium, and alumina from spent hydroprocessing catalysts by Gulf Chemical and Metallurgical Corporation and to review the use of sodium hydroxide and sodium carbonate for pressure leaching of spent catalysts.

Jan 1, 1986