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By Robert Ammon

THE purpose of this paper is to present a brief sketch of the development of this hindered-settling classifier, but primarily to show the actual results obtained in practice with the classifier working on the Butte copper ores at the Boston & Montana Concentrator, at Great Falls and the Washoe Concentrator at Anaconda. The writer has endeavored to be as brief as possible, giving only the essential figures showing the efficiency of the classifier and leaving considerable interesting information to be derived by the reader from the statistics given. The paper deals with the practical work of the classifier under the following heads: 1. Desliming 4.0-mm. primary feed, overflow from 0.07 to 0.0 mm. 2. Desliming 1.25-mm. secondary feed, overflow from 0.07 to 0.0 nun. 3. Desliming Huntington Mill discharge, overflow from 0.07 to 0.0 mm. 4. Classifying 2.5-mm. deslimed secondary feed, overflow from 1.00 to 0.07 mm. 5. Classifying 2.5-mm. deslimed primary feed, overflow from 0.75 to 0.07 mm. 6. Classifying 4.0-mm. deslimed primary feed, overflow from 0.75 to 0.07 mm. 7. Classifying middling-tailing product from roughing tables, overflow coarse tailing. 8. Classifying 2.5-mm. trommel undersize, not deslimed, overflow from 0.75 to 0.0mm. 9. Remarks on the inner feel cone. In the following pages all overflows, are given in quartz dimensions; i.e., by a 0.75-mm. overflow 'is meant an overflow whose maximum particle is a 0.75-mm. quartz grain. By the term "slime" is meant all material which will pass through a 200-mesh screen whose average opening is 0.07 mm.

Jan 8, 1913

A Page Adam. H. F. and Ruggles! G. H., Results with Xanthate at Inspiration............. 337 Adnic proertiea of....................... 474 Africa; Gold Coast, manganese...........abs.474 191 mining districts......................... 254 Aid, H., biography........................ 154 Air compressors. In flotation................ 45 Air-gas lift: gae-oil ratios relation of......abs. 475 Gulf Coast. mechanical installations... .abs. 475 Seminole field........................abs. 476 Air-sand process. cleaning coal............abs. 89 Alabema, Birmingham district. drainage. . abs. 86 " Alclad." aluminum alloy................. 395 Alexander. W. Homer. biomaphy .......... 37 Allen. Andrews. Preparing Coal after Mechanical Loaders......:....T................. 181 Allison. F. H., Comparison of the Effect of Nickel and Cobalt in Steel.............aha. 151 Alloys: See Metals named. Aluminum: heat treatment...............abs. 444 machining...........................abs. 443 Norway............................... *465 Aluminum alloys: " Alclad "................ 395 application of........................abs. 443 deformation..........................abs. 150 Aluminum Bronze Manufacturers Institute. organized.............................. 188 "Alumnum. The Metal and Its Alloys." B.R. 42 Aluminum-iron-silicon alloys, equilibrium relations.............................aba. 444 Aluminum-manganese alloys, equilibrium relations in..........................aba. 87 Aluminum-silicon alloys. heat treatment. .abs. 398 American Association of Petroleum Geologists. annual meeting................... 81 American engineers. war memorial.......... 499 American Institute of Mining and Metallurgical Engineers: Committees: Douglas. James, medal...... 324 Geophysical Prospecting............. E. 204 Mining Medal........................ 324 Nominating: Election................. 235 report............................. 479 Constitution. votes for.................E. 494 Constitution and By-laws. draft of....... 374 Directors: Minutes of meeting.....110. 235. 323 publications.......................... 523 Directors adopt badge................... 324 Dues. increasing........................ 111 Dues are Due.......................... 236 Institute of Metals Division: annual lecture............................ 187 data sheets.......................... 187 Detroit meeting, (September). . .307. 353, 440 lecturer C. H. Desch................. 15 Local Section Committee. members..... 187 New York meeting (February)......... 115 Research Committee.................. 187 research problems..................... 6 Local Sections: Arizona............................. 365 Boston, meetings................40, 197. 486 Page American Institute of Mining and Metallurgical Engineers—Continued Chicago, meetings...40, 94, 156, 196,240,417 Chicago and St. Louis, joint meeting, Danville....................... 486, 527 Colorado, annual meeting.............. 285 Columbia, meetings 39, 93, 156, 196, 238, 286, 327, 365, 486, 527 El Paso, organized.................... 238 Fort Worth, organization meeting...... 485 Joplin-Miami Zinc, meeting.......... 286 Lehigh Valley: annual meeting......... 197 meetings...................... 239, 527 Los Angeles, meeting.................. 285 Mid-Continent, meeting............... 156 Minnesota, annual meeting............ 326 Montana, meeting.................... 40 New York, meetings................240, 284 North Pacific: meetings.... 39, 157, 197, 527 Fieldner, A. C, speaker............. 486 resolution.......................... 439 Oregon, officers....................... 196 Pittsburgh: meetings........... 156, 327, 526 mine transportation conference....... 485 St. Louis and Chicago, joint meeting, Danville........................... 486 San Francisco, meetings............... 92, 197, 239, 285, 439, 486, 527 Southern California, meetings 40, 157,197,283 Upper Peninsula, meeting.............. 486 Utah, meetings..........40, 93, 156, 239, 365 Washington, D. C, meetings 40, 93, 365, 528 Medals: Douglas, James................34, *84 Fritz, John, award, 1928.............. 480 Johnson, J. E., awarded T. L. Joseph... 83 Saunders, William Lawrence........... 34 meetings: Cleveland, April, 1927.......166, 207 Detroit, Sept., 1927............307, 353, 440 Fort Worth, Oct., 1927.........307, 353, 471 • future............................. E. 102 Knoxville, Nov., 1927.............. 480, 500 New York, Feb., 1927, announcements, programs, etc.................33, 50, *106 Salt Lake City, Aug...............306, *422 Members and jobs...................... 477 Membership, benefits.................8, E. 2 Officers and directors.................... *122 Open-hearth Conference................. 282 Petroleum Division: activities............ 186 annual meeting...................... . Fort Worth meeting............307. 353 471 luncheon............................ 91 New York Petroleum Club, officers..... 110 nominations........................23. 519 officers.............................. 117 President's trip. May.................281. 398 Publications: Directors discuss............ 523 Institute of Metals Division Volume... . 178 Petroleum Volume.................... 192 Technical Publications...........E. 294 323 Transactions. Vol. LXXIV. LXXV....00. 524 Review of the year.........:........... ...E. 104 Stockholders. report to..............E. 49

Jan 1, 1927

By Robert Ammon

The purpose of this paper is to present a brief sketch of the development of this hindered-settling classifier, but primarily to show the actual results obtained in practice with the classifier working on the Butte copper ores at the Boston & Montana Concentrator at Great Falls and the Washoe Concentrator at Anaconda. The writer has endeavored to be as brief as possible, giving only the essential figures showing the efficiency of the classifier and leaving considerable interesting information to be derived by the reader from the statistics given. The paper deals with the practical work of the classifier under the following heads: 1. Desliming 4.0-mm. primary feed, overflow from 0.07 to 0.0 mm. 2. Desliming 1.25-mm. secondary feed, overflow from 0.07 to 0.0 mm. 3. Desliming Huntington Mill discharge, overflow from 0.07 to 0.0 mm. 4. Classifying 2.5-mm. deslimed secondary feed, overflow from 1.00 to 0.07 mm. 5. Classifying 2.5-mm. deslimed primary feed, overflow from 0.75 to 0.07 mm. 6. Classifying 4.0-mm. deslimed primary feed, overflow from 0.75 to 0.07 mm. 7. Classifying middling-tailing product from roughing tables, overflow coarse tailing. 8. Classifying 2.5mm. trommel undersize, not deslimed, overflow from 0.75 to 0.0 mm. 9. Remarks on the inner feed cone. In the following pages all overflows are given in quartz dimensions; i. e., by a 0.75-mm. overflow is meant an overflow whose maximum particle is a 0.75-mm. quartz grain. By the term "slime" is meant all material which will pass through a 200-mesh screen whose average opening is 0.07 mm. The development of the classifier was commenced in the fall of 1910,

Jan 1, 1914

By Norman B. Braly

The following is not offered as an extended paper on the subject of shaft sinking, but more as a description of the present practice of shaft sinking in the Butte district. The Anaconda company is sinking at present the following shafts: Badger State, Moose, Mountain Consolidated, Mountain View, Pennsylvania and Tropic. At the High Ore and Leonard mines the shafts are being deepened by sinking two compartments and will subsequently be enlarged to the full working size by raising alongside the compartments which are now being sunk. The following other companies are also sinking shafts: Butte-Alex Scott, Butte and Zenith City, Boston and Corbin, North Butte Mining Co. (at the Granite Mountain shaft), East Butte Co. (at the Pittsmont shaft), and the Rainbow Lode Development Co. Shaft Timbering. The shafts of the Butte district, generally speaking, are of three compartments arranged in a straight line, and the pump compartment is usually arranged for the use of an auxiliary hoisting cage, as well as for carrying pipe lines and electric wires. The Rainbow shaft is practically square, and of three compartments. The length of the shafts outside of timber will vary from 17 to 22 ft., and the width from 6 ft. 6 in. to 7 ft. Fir timber is used in all shaft work. This may be obtained from the Coast, when it is known as Coast fir, or from Idaho or Montana, when it is known as native fir. The native fir seems to be the tougher wood, but it is hard to obtain clear lumber in the lengths and sizes necessary for shaft work. Some of the shaft timber of the Anaconda company has been treated with creosote as a preservative, but this practice has not come into general use, as the ground of the camp is so heavy that the timbers usually crush before they rot. The size of timber most used for shaft work is 12 by 12 in., while 10 by 12 in., 10 by 14 in. and 12 by 14 in. are used for some of the special pieces around the shaft. The new Leonard shaft is timbered with 14 by 14 in. wall plates throughout.

Jan 1, 1914

By T. E. Wakefield

Over several decades in Southern Africa the advance rates when sinking vertical shafts have declined significantly. The upside has been a substantial improvement in shaft bottom conditions and a commensurately improved safety performance, with an increasing number of shafts being sunk without fatalities and disabling injuries. This paper briefly reviews historical sinking rates and matches changed sinking productivity to the introduction of new sinking methods that have been adopted to eliminate/mitigate safety risks. Meeting the challenge of returning to historical advance rates whilst progressing in the quest for zero harm by utilizing three dimensional animated computer modelling is described. Making use of commercial modelling software makes it easier to evaluate different methods, sequencing, in shaft barrel ergonomics, and stage and shaft bottom layouts before procuring project plant and equipment. Benefits accrue not only in better communicating methods and configurations for detailed planning and design, but also during crew training. The traditional engineering ?as-built? drawing practice has been extended to the concept of an ?as executed? sinking model which seeks to capture operational experience and learning for future best practice. The paper concludes with some of the organizational culture challenges being overcome as this non traditional approach to shaft sinking optimization is being introduced.

Jan 1, 2009

By H. E. Thomas

[The Bureau of Mines has conducted a field hydraulic fracturing experiment to determine the preferential orientation of induced fractures in oil shale at a depth of about 400 feet in the Green River Basin of Wyoming. The hydraulic fracturing treatment was performed by injecting extremely viscous water-base gel and 8- to 12-mesh sand into the oil shale through straddle packers set in an impermeable section of smooth-walled, 6-1/4-inch-diameter open hole. An impression packer proved that a horizontal fracture, which has an average width of about 1/2 inch at the borehole, was induced. A corehole drilled 100 feet from the fractured well intersected the fracture and confirmed its horizontal orientation. Because a horizontal fracture was successfully initi¬ated, it is inferred that the creation of multiple, closely spaced horizontal fractures may be feasible in Green River Basin oil shale.]

Jan 1, 1972

By Alberto Eloy Anduze Nogueira

A pelotização é o método de aglomeração de minério que oferece o melhor custo benefício. No processo, é necessária a adição de um aglomerante para conseguir as propriedades desejadas. Entre estes, o cimento é um dos destaques pela facilidade e custo. A adição de pozolânicos no concreto na construção civil para o aumento da resistência é de longa data. Neste trabalho, se estuda o efeito da adição de 1% de SiO2 ou bentonita na mistura das pelotas autorredutoras. Realizam-se ensaios de compressão a frio, compressão após tratamento térmico 950°C, Teste de abrasão a quente, teste de quedas, além de difração de raios-X. Como resultados obteve-se um incremento da resistência a compressão a frio e a abrasão a quente com a adição da bentonita, porém com ambos pozolânicos tem-se uma perda de 50% na resistência a compressão após tratamento térmico a 950°C.

Aug 1, 2018

By Geoffrey Berry

Exposure?response relationships between the relative risk of lung cancer and quantitative measures of exposure to asbestos are available from a number of epidemiological studies. Meta-analyses of these relationships have been published by Lash et al. (1997) [Lash, T.L., Crouch, E.A.C., Green, L.C., 1997. A meta-analysis of the relation between cumulative exposure to asbestos and relative risk of lung cancer. Occup. Environ. Med. 54, 254?263] and Hodgson and Darnton (2000) [Hodgson, J.T., Darnton, A., 2000. The quantitative risks of mesothelioma and lung cancer in relation to asbestos exposure. Ann. Occup. Hyg. 44, 565?601]. In this paper, the risks derived in these meta-analyses have been compared. Lash et al., concentrated on process and found that the risk of lung cancer increased as the asbestos is refined by processing. Hodgson and Darnton concentrated on fibre type and found that the risk was highest for exposure to amphibole asbestos (crocidolite and amosite), lowest for chrysotile and intermediate for mixed exposure. Some of the differences between the conclusions from the two meta-analyses are a consequence of the choice of studies included. The range of asbestos types included in the studies in the analysis of Hodgson and Darnton was wider than that in Lash et al., enabling differences between fibre types to be analyzed more readily. There are situations where occupational exposure to chrysotile asbestos has shown no detectable increase in risk of lung cancer. Taconite miners have shown no increased risk of mortality due to lung cancer. © 2007 Elsevier Inc. All rights reserved. Keywords: Mesothelioma; Amosite; Grunerite; Taconite; Crocidolite; Tremolite; Anthophyllite; Winchite; Risk assessment; Etiology

Jan 1, 2007

By George F. Becker

A Nere record of Emmons's professional career would very inadequately represent the man. That he was eminent mc know, and our successors will realize in due time; but they must depend upon us for knowledge of a singularly ~vholesome, modest, unselfish personality, and of a character that did honor to a profession in which trustworthiness is indispensable. Those members of the Institute who met Emmons are his friends, and I never knew .one of these who was not the better for that friendship. Emmons was born in Boston, Mar. 29, 1841, the son of Xathaniel H. and Elizabeth (Wales) Emmons, and was named Samuel Frankliri after an ancestor who was of the sarne family as Benjamin Franklin. He took the degrcc of Bachelor of Arts at Harvard in 1861, and soon afterwards went abroad to complete his education. From 1862 to 1864 he attended the courses at the fieole Impkriale des Mines at Paris, Elie de Beaumont arid Daubrke being among his professors. The year 1864-1865 he spent at Freiberg under Cotta and other famous teachers; after which he spent another year in traveling through Europe. Like many other renowned geologists, he approached his ultimate profession from its economic side, and was thus from the first imbued with a sense of high responsibility in the promulgation of scientific opinions or conclusions. With hypotheses which were interesting merely because they were ingenious or even plausible, he would have nothing to do. In 1867 he joined the Geological Exploration of the Fortieth Parallel at its organization under Clarence King, serving at first as a volunteer, but soon receiving a regular appointment. This expedition was the first one of purely geological character sent out by the United States government. As Emmons has shown in his admirable presidential address on " The Geology of Government Explorations," its work was founded on a com-

Jan 1, 1912

By CLARESCE CARLETON SEJIPLE

(Wilkes-Barre Meeting, June, 1911.) AT a number of mines in eastern Nicaragua, 3.5- and 5-ft. Huntington mills are used for grinding gold-ore after a preliminary breaking in jaw-crushers. The smaller mills are made sectional to facilitate transportation to the more difficultly accessible mines. The capacity of the smaller mills is about 20 or 25 per cent. that of the larger, but in proportion to the quantity of ore ground they require more power and are subject to greater wear. The notes herein given are from records of the performance of the larger mills, but, in general, apply to the smaller also. THE NATURE OF THE ORE. The ore occurred as a series of flat veins in a highly-decomposed rock, probably alaskite. The primary mineralization comprised pyrite, pyrrhotite, marcasite, chalcopyrite, and quartz; the oxidation-products of which were chiefly hydrated iron oxide or limonite, chrysocolla, azurite, and malachite. The kaolinization of the feldspar of the country resulted in the admixture of a great quantity of clay with the oxidized ore. The quartz was sandy, imbedded in the clay; and probably the greater part represented the residue from the crushed rock in the fissures after leaching, and kaolinization of the feldspar. There was little vein-quartz in the unaltered primary sulphide ore. Only the oxidized ore was mined for the gold that it contained in amounts that averaged $4 per ton. No specks of gold were ever seen in the ore, and the gold obtained by panning was always exceedingly fine. The amalgamation-bullion was about 800 fine in gold and 60 to 80 in silver. The ore delivered at the mill contained from 5 to 15 per cent. of moisture; during the rainy season the quantity was much greater. The moisture and clay made the ore so sticky that it had to be raked over steeply-inclined grizzlies; it hung in the ore-bins,

Oct 1, 1911

By Patrick J. Maessen, Bart H. M. Hendrix

"In the Netherlands, the Dutch Tunnel Standard has been developed for the execution of road tunnel projects. The Dutch Tunnel Standard is based on the Dutch Tunnel Law (WARVW) which sets the minimum safety standard for road tunnels in the Netherlands. Uniformity of tunnels and the uniform perception of a tunnel by its users leads to a higher safety level. Therefore, several items in the Dutch Tunnel Standard are specifically developed to ensure safety in emergency situations through the plane of human factors. Taking human factors into account is important in regular traffic situations, but in an emergency situation, this can be vital. In this paper, the development and contents of the Dutch Tunnel Standard are explained in the first part and in the second part, the systems related to human factors are described. DUTCH TUNNEL LAW AND THE NEED FOR THE DUTCH TUNNEL STANDARD In the 90’s of last century and the early 2000’s, several serious accidents occurred in tunnels in Europe. These accidents involved fire and led to many casualties. After these accidents, the European Union decided to change the regulations for tunnel safety, leading to the EU directive 2004/54/EG. The primary goal of this directive is, that casualties are minimized in case of a calamity in a tunnel (e.g. fire). In the Netherlands, the EU directive led to the development of the tunnel law and a tunnel regulation (in 2006) to prescribe the safety features required for a safe tunnel. The new Dutch tunnel law – cited in the Building Act – was meant to make tunnel design easier – but resulted at first in the opposite effect. Tunnel design in the Netherlands and design standards of Rijkswaterstaat Rijkswaterstaat – the executing organisation of the Dutch Ministry of Infrastructure and the Environment – is the owner of the tunnels in the Dutch national motorway network, thus owner of the majority of the road tunnels in the Netherlands. In the early years of tunnel building in the Dutch national highway network (approximately 1950 – 1970), Rijkswaterstaat was not only owner, but also designer of its own assets. Most Dutch tunnels are submersed tunnels, because these type of tunnels provide a cost-effective way to make river crossings. Another type of tunnel that is used, is a TBM tunnel. Because of the geological conditions in the Netherlands (merely clay/peat and sand), there are no NATM or drill-and-blast tunnels in the Netherlands. Since the last decades, land tunnels (covered roads) are becoming more common to provide for multiple use of surface space and to meet more modern environmental regulations as traffic increases near densely populated areas. Tunnel lengths in the Netherlands vary from 500 m to 1.5 km for river crossings up to 6 km for the Western Scheldt (bored) tunnel. The lengths of land tunnels vary from 500 m up to 3 km. With these increasing lengths, some safety topics and design topics arise, topics that were non-issues in the past, when tunnels were only used as river crossings."

Jan 1, 2016

By Mary Ann Bennett, Val Nichols, Colleen Proctor

"In 1997 when Royal Oak Mines Inc. went into receivership, the mineral processing technicians (mill operators) who had been working at Giant Mine in Yellowknife, Northwest Territories for most of their career walked out with no credentials to serve as testimony of their knowledge and skills.As a result of new diamond mining activity and the establishment of socio-economic agreements, mining industry representatives approached the Department of Education, Culture and Employment (ECE), Government of the Northwest Territories, in 1999. They requested support and direction to promote training and recognition for mineral processing technicians at BHP’s (BHP Diamonds Inc.) Ekati mine. ECE recommended the development of occupational standards and certification.This paper describes the development process and end products that resulted from this collaborative project between industry, government and education. In addition, industry representatives involved in the project share their views on the development process and the benefits of standards and certification.The conclusion invites industry members to support national occupational standards and certification with their associated benefits: standardized training in the workplace and institutions, proof of competence for hiring, recognition of prior learning, and a nationally and internationally recognized credential.INTRODUCTIONSwiftly changing labour market demands are nothing new in the North. The fur trade and mineral discoveries have brought employment to workers in a feast and famine cycle for decades. In the late 1990s, the Giant, Con, Lupin, Polaris and Nanasivik mines were nearing the end of productive runs. Many experienced workers found that without credentials, they had no proof of their abilities to offer prospective employers."

Jan 1, 2005

By M. R. Hudec, M. A. Nikolinakou, P. B. Flemings

"We model the shale response to the large deformations associated with salt bodies, and we identify the implications of the stress changes for hydrocarbon exploration. We employ both the static and evolutionary approach, and show that while the static one can model actual geologic geometries, only the evolutionary approach can provide a detailed description of the stress history of shales, which is essential for predicting stress, porosity, and pore pressure and, more generally, for understanding Earth processes related to salt-hydrocarbon systems.INTRODUCTIONDuring the last two decades, understanding the stress, material behavior, and pore pressure in shales around salt bodies has become increasingly important. The energy industry routinely drills near salt (Beltrão, Sombra, Lage, Fagundes Netto, & Henriques, 2009; Meyer, Zarra, Rains, Meltz, & Hall, 2005; Seymour, Rae, Peden, & Ormston, 1993), because a significant number of hydrocarbon reservoirs around the world are found in layers dipping away from salt diapirs.Salt is a viscous material that cannot sustain deviatoric stresses. Under differential loading it flows, changes shape, and eventually relaxes to an isostatic stress state (Urai & Spiers, 2007). Therefore, emplacement of a salt body and its viscous relaxation process may cause significant deformation of the surrounding sediments, perturb their state of stress and create local overpressures (Dusseault, Maury, Sanfilippo, & Santarelli, 2004; Seymour et al., 1993). As a result, drilling near salt is particularly challenging, and problems leading to additional expense or even abandonment are common (Bradley, 1978; Dusseault et al., 2004; Meyer et al., 2005; Seymour et al., 1993; Willson et al., 2003).Historically, salt and the evolution of its cross section to the present day geometry have been studied using kinematic restorations (Rowan & Ratliff, 2012). This approach aims to explain the present geologic section through a sequence of plausible past sections; however, it does not model the constitutive response of the wall rocks, hence it cannot provide any prediction on their state of stress. Similarly, largestrain numerical studies (Albertz & Beaumont, 2010; Chemia, Schmeling, & Koyi, 2009; Goteti, Ings, & Beaumont, 2012; Gradmann, Beaumont, & Albertz, 2009) have focused on the rheological evolution of salt systems without modeling the geomechanical response of the sediments."

Jan 1, 2015

By S. C. Robinson

"IntroductionALTHOUGH most uranium deposits of the Canadian Shield lie along its western and southern margins, those of the Lake Athabasca region extend easterly along the north shore of the lake and beyond to Charlebois lake. The western end of this belt of deposits, in the vicinity of Goldfields, is 80 miles from the Palaeozoic contact, and its eastern end, at Charlebois lake, is 240 miles from the nearest Palaeozoic rocks.Deposits in this belt may be grouped in four districts, which are, from west to east:(1) The Goldfields district, an area approximately 20 miles square, centred on Beaverlodge lake and extending eastward from St. Joseph's point to Moose channel.(2) A small area in the vicinity of Sucker bay, which is about l0 miles east of Fond du Lac.(3) An area including Middle lake to the northwest shore of Black lake at the Nisto mine.(4) A fairly large area extending northward from the eastern end of Black lake, through Charlebois lake to Spreckley lake.HistoryThe region has stimulated interest in mining circles since the reconnaissance survey of J. B. Tyrrell of the Geological Survey of Canada in l893, who reported concentrations of iron along the north shore of lake Athabasca. The deposits were staked and re-staked up to the early 'twenties' but are too lean to form ore."

Jan 1, 1952

By T. Hollenberg, N. Nolten

The mining industry is one of the major energy consumers in Namibia. Energy costs increase the operating costs of Namibian mines, in particular, the processing plants, and result in an overall increase of production costs. A substantial part of the energy used is directly imported from South Africa. The cost of energy has been increasing rapidly in the past few years and will most likely continue to do so in the future. In 2015, the average wholesale price for energy from national power utility NamPower was US$87/MWh after rising more than 12 percent annually in the two previous years. At peak times, which are early in the morning and late in the evening, imported-energy prices are extremely high and have to be factored into the electricity tariffs. This problem is expected to intensify due to a projected 4 percent annual increase in energy demand. A major target of the Namibian mines, therefore, is to consider possible ways to address energy-saving challenges and to investigate possibilities for the mines to generate electricity internally during peak times. This is in alignment with the mines’ strategic plans and objectives to reduce total energy consumption and costs from both national and foreign electricity suppliers. In this paper, we explore addressing some of the key energy consumption and optimization challenges through process energy reuse and solar energy production to decrease demand for imported energy through a case study carried out in cooperation with Skorpion Zinc Mine and Refinery.

Jan 1, 2018

By E. A. Rychkun

Mining and environmental objectives have traditionally been in conflict. This conflict reflects a delicate balance between the need to spend money to protect the environment, and the need to save money by extracting minerals efficiently. In an increasing number of cases, profit margins diminish rapidly with new environmental regulations and reactionary measures. Forced cleanups and increasing restrictions are unwelcome expensive processes. A practical solution lies in planning rather than reacting. This requires the ability to precisely quantify and qualify environmentally sensitive problems by providing effective engineering tools to model, visualize and analyze subsurface conditions. Prevention of environmental conflicts, and effective cost control are both rooted in the mining company's ability to construct accurate models, monitor changes, assess contamination risks and to design effective remediation plan. This paper presents a case study where these issues are addresses through the application of a new and innovative technology.

Jan 1, 1993

By Lisa J. Renaud

For generations, the mining industry has been committed to work toward developing new technology that can improve safety and increase production. Now with a more environmentally conscious society and tighter environmental regulations, a natural progression for the industry is to develop and take-on ?green? or environmentally friendly technologies. Not only could this improve the sustainability of operations, but could also reduce the long-term environmental impact footprint that is left behind. Algae represent a new frontier in research and development. As discussed specifically in this paper, algae, specifically microalgae, can be used for the production of biodiesel and other green chemicals by exploiting carbon dioxide and waste heat contained within process off-gasses. The potential positive benefits of this approach in terms of contribution to community and the environment are significant, and the focus of our research and development on microalgae production technology.

Oct 1, 2010

By Norman Braly

THE following is not offered as an extended paper on the subject of shaft sinking, but more as a description of the present practice of shaft sinking in the Butte district. The Anaconda company is sinking at present the following shafts: Badger State, Moose, Mountain Consolidated, Mountain View, Pennsyl-ania and Tropic. At the High Ore and Leonard mines the shafts are being deepened by sinking two compartments and will subsequently be enlarged to the full working size by raising alongside the compartments which are now being sunk. The following other companies are also sinking shafts: Butte-Alex Scott, Butte and Zenith City, Boston and Corbin, North Butte Mining Co. (at the Granite Mountain shaft), East Butte Co. (at the Pittsmont shaft), and the Rainbow Lode Development Co. Shaft Timbering. The shafts of the Butte district, generally speaking, are of three compartments arranged in a straight line, and the pump compartment is usually arranged for the use of an auxiliary hoisting cage, as well as for carrying pipe lines and electric wires. The Rainbow shaft is practically square, and of three compartments. The length of the shafts outside of timber will vary from 17 to 22 ft., and the width from 6 ft. 6 in. to 7 ft. Fir timber is used in all shaft work. This may be obtained from the Coast, when it is known as Coast fir, or from Idaho or Montana, when it is known as native fir. The native fir seems to be the tougher wood, but it is hard to obtain clear lumber in the lengths and sizes necessary for shaft work. Some of the shaft timber of the Anaconda company has been treated with creosote as a preservative, but this practice has not come into general use, as the ground of the camp is so heavy that the timbers usually crush before they rot. The size of timber most .used for shaft work is 12 by 12 in., while 10 by 12 in., 10 by 14 in. and 12 by 14 in. are used for some of the special pieces around the shaft. The new Leonard shaft is timbered with 14 by 14 in. wall plates throughout.

Jan 8, 1913

By Jaan Kiusalaas

This report is a self-contained User Manual for a computer program called SPASID -- Subsidence Prediction and System Identification. The program has two primary functions: (i) Precalculation of ground movements due to underground mining operations using the influence function method; (ii) Computation of influence function and site parameters from measured displacements. SPASID is written in FORTRAN and consists of four modules: (i) Preprocessor Module that prepares and maintains surface and mine data bases; (ii) Subsidence Computation Module that predicts movements of the surface; (iii) System Identification Module which is used to calculate the optimal influence function parameters, and (iv) Postprocessor Module for generating graphic displays of subsidence data. The last module is somewhat machine dependent but has internal documentation to indicate potential changes. All of the modules may be run in either batch or interactive mode. The manual does not assume previous knowledge of the influence function method or programming competence.

Jan 1, 1983

By Nathaniel R. Quick

"Nd: YAG, KrF excimer, and Cu-vapor lasers are used in air to synthesize conductors and semiconductors as a second phase in silicon carbide and aluminum nitride. Conductor resistivities as low as 104 O-cm are formed in these substrates; the resistivities for the untreated substrates range from 10 11to 1014 O-cm. The silicon carbide conversion is relatively independent of wavelength while the aluminum nitride conversion shows a dependence on wavelength over the range 248 nm to 1064 nm. Silicon carbide conductors, evaluated over the range 15 K to greater than 300 K, exhibit metal like conductivity; resistivity increases with temperature. Silicon, carbon, and oxygen are identified as the principal chemical species associated with the conductor in SiC substrates while aluminum, nitrogen, and oxygen are identified as the principal chemical species associated with the conductor in aluminum nitride substrates. The silicon carbide system, which has the less complex phase diagram, is evaluated in more depth to explain the synthesis mechanism. Oxygen was principally on the surface and increasing SiC conductivity is associated with decreasing spacing between 5 µm, or less, diameter carbon globules. This technology is proposed as a replacement for metallization in electronic packages, sensors and devices. INTRODUCTIONCeramics are commonly used for multichip module, hybrid and multilayer electronic packaging; semiconductor device and sensor applications because of the insulating, conducting, semiconducting, or superconducting properties that these materials possess (1,2) The majority of ceramics, however, have not been known to exhibit conductive or semi conductive properties when exposed to rapid thermal heat processing. A ceramic and process which through selective conversion can combine two or more of these electrical properties to eliminate the need for metallization is of interest to both the commercial and military sectors."

Jan 1, 1994