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By C. H. Hopper

DIAMOND drills have played an important part in the development of mines for many years. Recently. they have also entered the production field arid the use of diamond drills m the primary breaking of ores has become a big branch of the industry. The writer has estimated roughly that the total diamond drilling in Canada during 1942 was 5,625,000 feet, of which 2,250,000 feet, or 40 per cent, was for blast-holes. This accounts for 6,750,000 tons of ore broken, using the conservative factor of 3 tons per foot of hole. Many consider that the use of diamond drills for blast-holes is the most important advance in mine practice of the past decade, and the industry owes a great deal to the staff of Noranda Mines, Limited, for the pioneering they have done in the development of long-hole mining methods and for publishing their results. A great many mines have followed Noranda's lead. At the Waite-Amulet, Aldermac, Flin Flon, Canadian Malartic, Hoyle, and Matachewan Consolidated mines, most of the ore is broken by long-hole blasting. While the mines were developing new methods, the diamond-drill industry was developing mechanically-set bits and better machines. Through the effective use o smaller, cheaper diamonds, as well as more efficient setting, bit costs per foot are only one-half what they were ten years ago. Few people realize that a diamond bit is relatively inexpensive. The common EXT coring bit, for example, contains some 200 small diamonds, weighing altogether about 2.70 carats which, at $3.40 per carat, cost $9.20. After use, the equivalent of about 100 of these diamonds may be recovered. Therefore the true cost of the bit is only $7.00, made up of $4.60, the cost of the diamonds lost, $2.00 for setting, and $0.40 tax. The trend in machines has been toward specialization for the different classes of rock in blast-hole work. Light, high-speed machines have been developed for soft ores and higher powered machines for hard ores.

Jan 1, 1943

By Ernest W. Hilton

The purpose of this investigation was to assess the environmental impact of the surface mining methods currently used in the steep-sloped areas of Central Appalachia: southern West Virginia, eastern Kentucky, southwestern Virginia and northeastern Tennessee. Comparisons are made between mountaintop/cross ridge mining, contour strip, augering and an innovative method surface shortwall mining which was attempted at Julian, West Virginia. Included in this final report are a discussion and analysis of current Appalachian production, reserves, and the extent of land affected on a county- by-county basis. Additionally, the seams within the steep sloped region have been assessed according to minimal standards of thickness, surrounding lithology, and areal extent to determine their amenability to surface shortwall mining. These seams have been tabulated with their ash, sulfur, and BTU content on a county-by county basis. Only minimal statements are made concerning quantity because of the narrow set of conditions required by the shortwall method. Other sections deal with the possible technical failings of an operational surface shortwall system based on field studies at shortwall operations, discussions with people experienced with shortwalls and research into ground control problems at sites where short- and longwall operations have been monitored. A final section details proposed additional research directions which the Bureau might take in the future.

Jan 1, 1979

South Africa?s now a member of this body, tailored on the World Bank, and headquartered in Abidjan-Cote d'Ivoire. As a funding agency for capital projects within 59 member countries of the ADB it is to be expected that there are guidelines to the requirements for funding application and for project management and control.

Jan 1, 1996

By César Bernal M

El presente trabajo busca establecer el mejor plan de explotación de la mina Cobriza a través del nuevo proyecto de expansión. El plan de explotación señala que los ciclos de explotación, el número de tajeos requeridos por el método de corte y relleno, la selección del equipo de mina, así como los servicios auxiliares para suministrar el tonelaje necesario de mineral a la nueva planta de Coris.

Nov 8, 1982

Jan 1, 1969

By J. Bruce Clemmer

[Gypsum is one of the most important nonmetallic c minerals, as is indicated by the fact that the United States consumed approximately 3,500,000 tons of natural and calcined gypsum in 1937. The building trades were the largest users required 2,520,000 tons of calcine for production of plaster, wall board, tiles, block, and various other insulating and building materials. The glass and ceramic industries and other manufacturers required an additional 126,000 tons. The balance was used in the uncalcined condition as retarder in Portland cement and or agricultural purposes.]

Jan 1, 1941

By David R. Peterson

This report presents a deep ocean mining operational simulation which is capable of describing the response of the bottom collection unit to specified mining ship maneuvers and the corresponding operation of the mining ship maneuvering system. Bathymetry, obstacles, collector and pipe dynamics and ship maneuvering capabilities are included in the simulation. The simulation is capable of evaluating the technical requirements and operating costs for specified mine plans, Results are useful in assessing mine size requirements and provide operating 'cost 'estimates useful as inputs to deep ocean mining economic feasibility assessments, The simulation is used to determine the consequences of obstacles to mining system operations in terms of impact on mine size requirements and reduced production arising from obstacle avoidance maneuvers of a towed (unsteered) collector.

Jan 1, 1979

By K. B. Bengtson

This task report provides the process technology, preliminary design, capital and operating costs for a 25 TPD pilot plant to produce cell-grade alumina using a clay/hydrochloric acid extraction - HCI gas induced crystallization process. The report consists of six volumes: I - Process Technology and Costs; II and III - Equipment Lists, Specifications and Quotations; IV and V - General Specifications; VI - Drawings. The process was selected by the Bureau of Mines as the more promising method to produce cell-grade alumina from clay based on the results of the two previous task reports under this contract: Task I - Comparison of Six Processes (alunite, anorthosite-lime sinter, clay/sulfurous acid, clay/nitric acid, clay/hydrochloric acid evaporative and gas-induced crystallization) and Task 2 - Comparison of Two Processes (clay/nitric acid and clay/hydrochloric acid - gas induced (crystallization). The pilot plant process utilizes a unique dual crystallization process to produce aluminum-chloride-hexahydrate crystals having sufficient purity when decomposed to meet stringent alumina product specifications. The size of the 25 TPD pilot plant has been selected to permit scale-up to commercial size plants of equipment, technical and economic parameters. The capital cost estimate for the pilot plant, exclusive of fee and escalation, for a southeastern U.S. location is $52,311,000 expressed in 1979 dollars. The total time required to construct the pilot plant including engineering and procurement is 32 months. The operating cost to produce the estimated 9,000 tons of alumina required for testing in Hall cells is $40,91[0],190 expressed in 1979 dollars.

Jan 1, 1979

By Brent A. Elliott, J. Richard Kyle

Texas is a major producer of industrial mineral resources required by the state’s ever-growing population that now exceeds 28 million. Texas typically ranks in the top three states for the value of non-fuel mineral production with a total value of $5.2 billion in 2017, accounting for 6.9% of the total US mineral value. Almost 90% of current Texas industrial mineral value comes from the production of cement, crushed stone, industrial sand, and construction sand and gravel. Construction material consumption is focused in the 25 metropolitan areas of the state with populations of > 100,000 residents. Industrial mineral consumption is dominated by the four most populous regions of the state—Houston, Dallas-Fort Worth, San Antonio-New Braunfels, and Austin-Round Rock—with an aggregate population of more than 18 million. More than 11,000 employees work in Texas mining and processing operations. Texas produces more crushed stone than any other state from more than 200 quarries; a similar number of operations produce sand and gravel. Specialty industrial sand production for use as proppants in hydraulic fracturing for enhanced petroleum production serves as an excellent example of how developments in one industry sector can markedly affect another industry; the production of industrial sand in Texas has markedly increased over the past decade, reaching $1.3 billion in 2014. With Texas’ population projected to reach 50 million by 2050, continuing in-state development and production of industrial minerals will be required to supply its residential, commercial, and industrial users. Favorable geology and economic factors provide opportunities for identification and development of new industrial mineral production sites.

By Raymond L. Lowrie

Deregulation, as authorized by the Energy Policy Act of 1992 (PL102-486) allows free-market competition in the electric-utility industry. As the act unfolds, though, uncertainties abound about the type, degree and direction of impacts throughout the affected economy — from fuel suppliers to electricity generators and from power distributors to energy consumers. Instead of having a familiar base of captive customers and electricity prices fixed by negotiation with state public utility commissions, utility companies are preparing for open, free-market competition. They are looking at all areas, including fuel supply, to cut costs to remain competitive. Humorous anecdotes are told about utility companies shunning insiders for senior executive positions. Instead, they are opting for people from the telephone or other industries with deregulation experience. And there are light-hearted stories about a trend away from traditional electric-company names, such as the name of a city or state followed by Edison or Power and Light, to space-age names, such as Ameren, Entergy, Illinova or Unicom. No one wants to be left behind or be perceived to be left behind.

Jan 1, 1996

By E. Miller, K. L. Komarek

Equatiorzs have been derived which related maximum solid solubilities in semicondcting compounds having retvograde solidus curves with 1iqllidus data. Liquidus curves in Lke Pb-Te, Pb-Se, ard PB-S systetris have been defermined by thertrzal aralyses. Fvotrz expevimental maximum solibilities ia CdTe, PbTe, uxd PbS vetvograde tetrperatures hale beep1 calculated. TIze resllts support the concept that under certaiz conditiots pronounced itjlections in the liquidis curves arc indzcatiz:e of retropade solidus curves and that the tenlperatltre of the lmaximum solid solubility will be close to the temperature of the point of inflection in the liquidus curve. The maximum solid solihility within a gvoup of homologous cottrpoods SeetlLs to increase with increasing flatness ol the liquidus curvres. The phenomenon of retrograde solubility in metals, i.e., maximum solubility in a solid terminal phase in equilibrium with a liquid phase, has been theoretically predicted by Van aar' in his calculations of hypothetical binary phase diagrams. It was not until 1926, however, that retrograde solubility was experimentally verified in the Zn-Cd system.' Since then many sys- tems with retrograde solubility have been found, so that at present approximately fifty binary diagrams with a retrograde solidus curve are known.3 Meijering4 has critically appraised the accumulated data and has presented calculations which alloy predictions as to whether or not a solidus line will be retrograde. Interest in retrograde solubility increased when it was found that the solidus curves of germanium and silicon alloyed with a great many doping elements are retrrade. The problem was treated thermody-namically by odkinson,% d all available data on solid solutions in germanium and silicon were summarized by Trumbore.7 Although it is to be expected that intermetallic compounds will also exhibit retrograde solubility, experimental evidence is much more limited. Until now retrograde solidus curves have been reported for the compounds de,' be, Ps:" ne," SnSe," and SnS.13 All these compounds are semiconductors, and the solidus curves were usually obtained by determining the carrier concentration at room temperature of samples equilibrated at elevated temperatures and then quenched. It has been hown,'' however, that it is not always possible to quench in the equilibrium compositions from above a certain temperature. Theoretical discussions have either explicitly excluded intermetallic compounds4 or not treated them with respect to retrograde slubilit.j In the following a thermodynamic treatment of retrograde solu-

Jan 1, 1967

By R. L. Grayson

Focusing on relationships between severity measure versus productivity and other factors, this paper presents a comprehensive study of injuries for U.S. underground coal mines in 1996 by mine size. Based on analyses of data, generally the larger the mine, the more productive it is (in tons per employee-hour), but the more severe is its injury experience (r = 0.65). Within very large, large, and medium mine sizes, however, the more productive the mine, the less severe is its injury experience (r =-0.43, -0.36, and -0.26, respectively). For small and very small mines, a more deeply nested analysis is required to understand relationships. Other interesting relationships and comparisons are presented.

Jan 1, 2000

By G. E. McElroy

[The ventilation of development faces in mines for diluting gas or dust concentrations aid in hot mines for providing air-motion cooling affect, by fan-pipe units discharging high-velocity streams of air close to the face, is an important phase of mitre ventilation. The effectiveness of such units depends largely on the air-flow distribution between-the pipe discharge said the face, a subject on which little definite information is available. A study of the air, flow from grills into rooms3/ has provided sore basic data, but under conditions so different from mine fan-pipe installations in development ends that tae data to are of doubtful application to mine installa¬tions, owing to differences in air-flow conditions. The purposes of this report is to present and discuss the results of an initial series of tests of a general investigation designed to yield definite laws and design data for the discharge of fan-pine lines in nines. The s series was planned to yield preliminary data on the effects of velocity of discharge, size and shape of tripe, and adjacent calls on the air-flow distribution. Tents were made on 10-inch pine with seven different end conditions and one change of wall condition. Changes in size and shape of discharge wore made b y short transformation pieces directly at the discharge end, with the result that effects due to contraction and expansion of the flow, which proved to be of much greater importance than was expected, totally obscured any normal effects cue to size anti shape. The results of this series of tests, therefore, relate to 10-inch pipe with various discharge designs is and ago se reported.]

Jan 1, 1940

By Y. Ye

Typically, rougher molybdenite flotation and recovery from bulk copper/ molybdenum concentrates involves the use of alkalisulfides, Nokes reagents, cyanides, oxidants, and/or thermal treatment for the depression of copper sulfide minerals. The bulk copper/molybdenum feed generally varies from 0.2% Mo to 1.0% Mo, and with traditional reagents the single-stage rougher flotation recovery of molybdenite varies between 40 and 90% at a concentrate grade of 5 to 10% Mo. With ozone conditioning for copper depression, however, improved separations appear to be possible, as demonstrated by tests with Cu/Me concentrates from both the Phelps Dodge Morenci Operations and the Kennecott Copperton Operations. Single-stage rougher flotation after ozone conditioning can provide a molybdenum concentrate at a recovery of more than 90% and a rougher concentrate grade higher than 20% Mo in some cases. Subsequent cleaner flotation with additional ozone conditioning results in relatively copper-free molybdenum concentrates containing as much as 52% Mo. Preliminary analysis indicates that, with a multistage ozone conditioning/flotation strategy, the process is technically and economically viable and should be suitable for industrial application.

Jan 1, 1990

By Larry G. Stolarczyk

An underground medium frequency radio communications system has been developed and demonstrated in both coal and metal/non metal mines. The principal advantage of the system are its low cost, ease of installation and the ability to provide radio communications to any vehicle or roving miner in the underground mine. The system provides high quality radio coverage in work areas and along manways with existing "wireplant" conductors. The conductors include AC power cable, telephone cable, metal water and high pressure air pipes, etc. The measured communications range from the base station to mobile transceiver exceeded 12,500 ft without the use of repeaters. A cost/benefit analysis shows that the initial cost of the equipment can be returned 2-6 times in the first year. The mine productivity increases by approx. 13 percent.

By Dean R. Gehring

Creating projects to reach a goal is not new to American industry. In fact, all major construction projects, from skyscrapers to bridges, are completed using similar project management techniques. However, modern project management is relatively new. It was not formalized until 1962, when NASA and the US Department of Defense recognized the need to develop uniform project management procedures throughout the aerospace industry (Moder, Phillips and Davis, 1983). This management method was not introduced to the mining industry until the early 1970s (Britton, 1983). Project management typically follows an organized, four-stage process —definition, planning, implementation and control.

Jan 1, 1996

By X. (Mike) Yao

Rock mechanics engineers must provide ground support designs that ensure a safe underground working environment. Unexpected falls of ground are unacceptable while ground support systems must be adequate. Ground support must be economic for the area supported and the time frame the opening is in use. While numerical modeling can be used for ground support design, empirical models are still the common useful design tools. Empirical models are best developed and improved from local experiences although some models, such as Stability Graph (Potvin et al, 1992), are in extensive use by the Canadian mining industry. To determine the adequacy of ground support practices at HBMS, a database of 50 fall of ground case histories between 1985 and 2001 was compiled. For each failure, the recorded data included: location, rock type, rock mass conditions, opening and failure geometry, installed ground support and failure mechanism. An analysis of the database was done to obtain an understanding of failure frequency association with rock types, stope geometry and installed ground support, and to assess what support design changes were necessary. The paper describes changes made to ground support and mining practices during the last five years, and the formation of new ground support standards and practices which have been successful in reducing ground falls while providing improved, efficient and economical ground support.

May 1, 2002

By Olman Hee

This study investigates the identity and relative importance of factors affecting the future demand for phosphate rock, potash, and nitrogen. The main objective is to analyze demand relationships for these chemical raw materials for some specified past period, and to utilize this information to make projections of consumption into some designated future period. The end-use approach is used, which divides total consumption of each chemical raw material into agricultural, industrial, and export use. Multiple regression analysis is employed to statistically measure the relative effects of the different factors on consumption in each end use. The general method centers on the construction of a consumer demand model, the fitting of the respective equations in the model, and the interpretation of the statistical results. Direct and cross price elasticities of demand are computed for each end use of the chemical raw materials. These give an insight into expected changes in consumption with respect to given changes in price. The results of this study indicate that price, consumer income, and level of technology are factors which measurably affect consumption of chemical raw materials. For phosphate rock and potash, the agricultural and industrial end uses showed an inelastic demand, whereas for nitrogen, all end uses (including export use) exhibited an elastic demand. Among the chemical raw materials, average annual growth of consumption of nitrogen for agricultural and export uses to 1980 is expected to be notably higher than that for phosphate rock and potash.

Jan 1, 1969

By Frank A. Peters

This Bureau of Mines report is the second of a series of process evaluations planned to determine the relative processing costs of producing metallurgical-grade alumina from low-grade aluminous materials. Included in these evaluations are recommendations for additional research and development to improve the processes and to lower their costs. The design for each process is based on published work. The processes considered in this report are designed to extract alumina as aluminum chloride from calcined clay with 20 percent hydrochloric acid and to remove the silica residue by filtration. Iron is removed by one of the following processes: Isopropyl ether extraction, in which iron chloride is extracted before decomposing the aluminum chloride; gas precipitation, in which the aluminum chloride is precipitated with hydrogen chloride while leaving the iron chloride in solution; gas precipitation-isopropyl ether extraction, in which the aluminum chloride from precipitation is extracted with isopropyl ether, if necessary; caustic purification, in which a crude alumina is produced and then purified by a modified Bayer operation; or sinter purification, in which a crude alumina is produced and then purified by a lime-soda sinter operation. For plants producing 1,000 tons of alumina a day the estimated operating costs per ton of alumina are: [Isopropyl ether extraction process $ 65.09 Gas precipitation process 89.04 Gas precipitation-isopropyl ether extraction process 119.65 Caustic purification process 73.79 Sinter purification process 80.47] The estimated fixed capital costs per annual ton for these plants on a Marshall and Stevens chemical equipment basis of 240.0 are: [Isopropyl ether extraction process $229.03 Gas precipitation process 287.16 Gas precipitation-isopropyl ether extraction process 356.59 Caustic purification process 266.48 Sinter purification process 279.13]

Jan 1, 1962