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By W. P. Roux

Owing to decreasing high-grade ore reserves, there is a need for better understanding of the jigging process to improve the recovery efficiency of finer, lower grade material. The use of positron emission particle tracking (PEPT) was examined as a technique to study the motion of iron ore particles inside a laboratory batch jig. PEPT is a non-invasive method that can provide three-dimensional kinetic data on a particle in laboratory-scale processing units and has been successfully used to study mills, hydrocyclones, and flotation. Experiments were conducted to determine whether PEPT would be a viable technique to study iron ore jigging and what valuable information could be obtained. The results indicated that detailed information on the stratification rate of a particle could be obtained, with adequate resolution to track the particle?s movement through an individual jig pulse.

Jan 1, 2014

By Walter Smith

Environmental Quality Committee ?EQC was created in 1995 to facilitate dialogue between industry and northern communities and help build the understanding of the industry in those communities. ?EQC is made up of representatives from 32 northern communities. ?Meet regularly with Cameco to discuss on going and new projects. ?Tour mine sites on a yearly basis.

Nov 1, 2011

CONTENTS RUSSIA-R. C.-BECKSTROM 3 VENEZUELA-F. H. KAY 9 TRINIDAD-W. J. MlLLARD 20 RUMANIA-1. I. GARDESCU 26

Jan 1, 1932

By Efrem R. Reeves, David C. Byrne

This study was conducted as part of a project involving the evaluation of a new type of noise exposure monitoring paradigm. Laboratory tests were conducted to assess how “nonstandard” dosimeter microphones and microphone po­sitions measured noise levels under different acoustical condi­tions (i.e., diffuse ?eld and direct ?eld). The data presented in this article re?ect measurement differences due to microphone position and mounting/supporting structure only and are not an evaluation of any particular complete dosimeter system. To varying degrees, the results obtained with the dosimeter microphones used in this study differed from the reference results obtained in the unperturbed (subject absent) sound ?eld with a precision (suitable for use in an ANSI Type 1 sound level meter) 1/2 -inch (12.7 mm) measurement microphone. Effects of dosimeter microphone placement in a diffuse ?eld were found to be minor for most of the test microphones/locations, while direct ?eld microphone placement effects were found to be quite large depending on the microphone position and supporting structure, sound source location, and noise spectrum.

By Roger F. J. Adam

This report summarizes the principles of safely working steep coal seam using longwall mining methods. It presents the state-of-the-art and identifies the problems which result from seam inclination. Details are given on foreign longwall faces achieving good records of safety and productivity when mining on 30 degree and 50 degree inclined seams. Recommendations for further research are suggested.

Jan 1, 1981

By Matheus Sexto Alexandre Pereira

Controle e centralização de informações referentes ao processo industrial são imprescindíveis e considerando-se que na cadeia de suprimento o maior valor agregado costuma estar na produção, faz todo sentido investir em sistemas que possibilitem a otimização do fluxo, controle e qualidade do processo. O novo Sistema de Controle de Panelas (SIPAN) implantado na CSN permitiu monitorar em tempo real todo o ciclo operacional utilizando novas tecnologias de desenvolvimento de software web, além de melhorar o gerenciamento, comunicação com outros sistemas e rastreabilidade de todo o processo. O sistema implementado conseguiu melhorar a qualidade de informação para a equipe tornando mais rápida e assertiva a tomada de decisão.

Jul 30, 2018

By G. T. Krempasky

In an attempt to develop a suitable precast concrete support for underground use, two different models (1955 and 1958) of a five-piece concrete set were designed, fabricated, and tested under adverse loading conditions. Model 1955 was designed to withstand an ultimate, uniformly distributed, vertical load equivalent to what a three-piece, 12- by 12-inch wood set of intermediate-grade Douglas fir would withstand. A design figure of 138,000 pounds for the vertical load was used on both the 1955 and 1958 models. In addition, the 1958 model was designed to withstand a uniform horizontal load of 7,000 pounds per foot and additional concentrated-point loading. The step- by-step design of each model is presented in the appendixes. A series of five destruction tests was conducted underground on the 1955 model, and results of the tests showed that the type and method of blocking were of major significance.

Jan 1, 1963

By Jesse R. Jacobson

A large casino complex in Cherokee, North Carolina recently underwent a $633 million expansion that involved substantial foundation challenges. The site is located in a valley on the southern edge of the Great Smoky Mountains National Park, where subsurface conditions typically consist of varying thicknesses of fill overlying alluvium, residuum, partially weathered rock and rock. The fill and alluvium contain cobbles and boulders as large as several feet in diameter. The residuum and partially weathered rock are very thick in some areas, and the depth at which consistently high quality rock is encountered is highly variable. To reduce the foundation costs for the expansion, continuous flight auger (CFA) piles were proposed in lieu of micropiles. CFA piles are not generally used in this geologic environment and concerns regarding their selection included: (1) an uncertainty that CFA piles could be successfully constructed given the difficult conditions and (2) a lack of regional data regarding unit resistance values and load transfer characteristics. To address these concerns, a design-phase test program was undertaken to evaluate pile constructability, develop an understanding of the load transfer behavior, and establish the required pile lengths. The program included soil test borings, shear wave velocity measurements, timed auger probes, instrumented pile load tests and observation of exhumed piles. It was demonstrated that CFA piles could be advanced through the fill, cobble/boulder-laden alluvium, residuum and into the partially weathered rock, albeit with some limitations. Under axial loading, the pile response was very stiff and relatively high unit resistance values were measured. Pile instrumentation allowed for the evaluation and use of design pile lengths shorter than that tested, and the overall reduction in pile lengths yielded a 40 percent reduction in foundation cost. In general, CFA piles were determined to be a suitable, economical foundation alternative.

Jan 1, 2011

The following data are put together to assist those who are responsible for ordering stores for mines and works. When making out a list of mine stores for a new plant, one can hardly be expected to remember everything, still it is all the more important that articles should not be forgotten, should the mine be situated in an out of the way place, where the manager has to look several weeks ahead. A man who has been accustomed to buy stores on a small scale, from local merchants, where he could pick out personally what he wanted, may suddenly find himself in a place where he has to order wholesale quantities or make out store lists to send contractors for quotations. As it is of course cheaper to purchase stores by the hundredweight, coil, barrel, etc as the case may be, in which they are made up, than to break such a parcel, the way in which the materials are placed on the market is mentioned, so that those who don't know may take full advantage of wholesale terms. The most frequent sizes and brands employed in connection with Australian mining are also mentioned. It would be useless to enumerate all sizes made by the trade, as many would be of no value for our purpose; still I have put down what will serve as a reminder to the manager to mention what size he requires when giving an order, such as the diameter of dynamite cartridges a slight neglect of this sort has often caused serious delay. By mentioning certain brands I do not wish to recommend them in preference to others inadvertently omitted they are simply mentioned as some of those frequently met with.

By Henry Kreisinger, John Blizard, B. J. CROSS, C. E. Augustine

This report gives the results of 26 tests of a four-pass Edgemoor boiler fired with powdered coal at the Lakeside station of the Milwaukee Electric Railway & Light Co. The tests were made by the fuel section of the Bureau of Mines in cooperation with the research department of the Combustion Engineering Corporation and the operating department of the Milwaukee Electric Railway & Light Co. The object of the tests was to determine the thermal efficiencies and capacities obtainable by burning powdered coal under large central-station boilers, and the possibility of operating such boilers continuously at high efficiency and capacity without destructive effect on the furnaces and without difficulties in refuse removal. In any system for burning pulverized coal the furnace is the most important part because, to justify the cost of pulverizing, the powdered coal must be burned with higher efficiency than coal fired with mechanical stokers. In other words, it is the furnace that by giving higher thermal efficiency must pay for the installation, maintenance, and operation of the pulverizing equipment. No matter how simple the apparatus for the preparation of pulverized coal may be, or how simple the pulverizing process, unless the furnace is so designed that it can be operated continuously with high thermal efficiency, the whole system is a failure. For high thermal efficiency the coal must be burned almost completely with low excess air. But low excess air and complete combustion give high furnace temperature, which in turn causes erosion of the furnace lining and fusion of the ash; and removal of the fused ash is difficult. The necessity of complete combustion with low excess air thus brings with it these two important problems in the design of a furnace for burning powdered coal: 1, Prevention of erosion of the furnace lining; 2, easy removal of refuse from the furnace. For the purpose of solving these problems, the boiler tested was equipped with a furnace having hollow walls, through which about 60 per cent of the air needed for combustion passed before it entered the furnace. By passing through the hollow walls, the air cooled the furnace lining and prevented excessive erosion. A water screen was placed in the furnace about 3 feet above the bottom to keep the refuse deposited at the bottom from fusing and to make its removal easy. The design of the furnace, water screen, and burners was based on the experience gained in the previous cooperative tests1 with a smaller furnace, experimental water screen, and burners at the Oneida Street station of the Milwaukee Electric Railway & Light Co. The boiler tested had 13,057 square feet of heating surface. It was one of eight boilers fired with powdered coal, and was designated as boiler No. 8. The Lakeside station is the largest central station in the world that burns powdered coal exclusively. The coal used in the first five tests came from Illinois. The fuel in the other tests -:vas a mixture of Illinois and Pittsburgh coals.

Jan 1, 1925

By R. S. Dean

This report, the second of a series of annual reports of the Metallurgical Division to be released in this form covers the fiscal year July 1, 1935, to June 30, 1936. The technological work of the division is performed by sections. Thus, an efficient organization is provided to prosecute the various problems under investigation, and a logical system is set up for presenting the material contained in this report.

Jan 1, 1937

By William H. Lewis

Energy Research Corp., under contract to the Bureau of Mines, has developed a new miners' caplamp battery. The new battery is based on nickel-cadmium technology and offers significant improvements in performance with reduced size and weight when compared to the conventional lead-acid battery presently in use. This report describes the design and fabrication of the nickel-cadmium battery, which utilizes a roll-bonded electrode structure. The final battery design has a 15-A-h capacity in a 2-112-lb package, which is over 2 lb lighter than the present lead-acid caplamp battery.

Jan 1, 1983

By H. A. Dierks

Implementation of the joint Federal-State control program established in 1955 to cope with the mine water problem in the Pennsylvania anthracite region is described in this report. The increasing severity of the water problem in the anthracite mines has necessitated major adjustments as this continuing program has progressed. Since 1941 the Federal Government has recognized the mine water problem as an important factor in the worsening economic condition of the anthracite region by initiating scientific and technologic investigations and establishing the Anthracite Flood-Prevention Section in the Bureau of Mines in 1948. On the basis of comprehensive investigations and studies, the results of which were published in numerous reports and bulletins, the Anthracite Mine Drainage Commission of the Commonwealth of Pennsylvania formulated a plan that served as a background for legislative action in 1955, resulting in Public Law 162, 84th Congress (Act of July 15, 1955 (69 Stat. 352; 30 U.S.C. 571-576)), for the Federal Government, and Act No. 82 of the General Assembly, July 7, 1955, for the Commonwealth of Pennsylvania. The report covers 29 mine flood control projects approved and executed in implementing the aforementioned legislative acts. Essential engineering and cost details for each project are given, together with an evaluation of the effect that the installed facilities have on alleviating the mine water problem as it concerns individual mines and the anthracite industry as a whole.

Jan 1, 1962

By Y. P. Lu

PET/kaolin nanocomposites were prepared with melt blending and the structure of the composites was characterized through IR techniques. The results showed that there is stable chemical bonding between PET and kaolin. In addition, the dispersion condition of nanokaolin was observed by means of SEM and TEM. As a result, the thickness of the dispersed nanokaolin particles in PET matrix is mainly from 20mm to 200nm, and the nanosized particles congregate to some extent in the samples. In addition, it was found the kaolin particles almost homogeneously dispersed in the PET matrix, without preferential orientation because of the shear effect due to melt blending. Furthermore, the mechanical properties of PET/kaolin nanocomposites are dependent on the modification efficiency of nanokaolin. With the poor efficiency, the nanokaolin particles tend to aggregate at a high content and have a bad interfacial compability between nanokaolin and PET matrix, which lead to stress concentration, so the mechanical property descends. Experiments of different contents of modified nanokalin indicated that the intensity of PET/kaolin nanocomposites decreased firstly, then increased, and then decreased, with the nanokaolin content of 4 to 5 percent, the rupture stress of the composites showed a maximum value, which was higher than that of pure PET. On one hand, nanokaolin decreases the function among PET macromolecules, which will decline the mechanical properties, on the other hand, the piece structure of kaolinite improves the intensity of the nanocomposite. When the nanokaolin content is low, the former has the dominant effect on mechanical property, while the latter will play a leading role with the content increasing. But if the nanokaolin content still increases, the agglomeration and stress concentration will be obvious.

Jan 1, 2014

By Carlos G. C

Geological mapping in various parts of Australia is revealing a number of regional associations of mineralizations with particular persistent stratigraphic horizons. Such associations have been found in the Broken Hill district of New South Wales, in the Nairne district of South Australia, in the Mount Isa district of Queensland, and in the Cloncurry district of Queensland. The question has arisen as to whether such mineralizations are of sedimentary origin, syngenetic with the enclosing formation, or whether they are of epigenetic origin, and reflect the selective hydrothermal mineralization of favourable beds on a regional scale.The purpose of this investigation is to test the use of sulphur-selenium ratios as an objective method of distinguishing between suphide deposits or sedimentary or supergene origin, and sulphide deposits of hydrothermal origin, with particular application to the districts mentioned. At the same time much data has been accumulated as to the selenium content of Australian sulphide ores. The possible use of sulphur-selenium ratios for this purpose was first demonstrated by Goldschmidt and his coworkers (1933; 1935), and later by Carstens (1941). Goldschmidt and Strock (1935) found that pyrite of sedimentary origin had a sulphur : selenium ratio of the order of 200,000 or more, whereas pyrite of hydrothermal origin had a sulphur: selenium ratio of 10,000 to 20,000. Carstensfound that sedimentary pyrite deposits in Norway contained less than 1 g. Se per ton, whereas hydrothermal pyrite deposits contained 20 to 30 g. per ton.

Jan 1, 1954

By S. J. Haynes

"This paper documents the characteristics of the different quartz veins, and their relation to gold, in the turbiditic Meguma domain of eastern Nova Scotia. Eleven different types have been distinguished in the greenschist facies on the basis of form, internal structure, mineralogy, wallrock alteration and crosscutting relationships to each other and to regional structures. Gold is present as rare visible disseminations in host rock slates and in ore-grade, early-formed veins, that pre-date the formation of upright Acadian folds and intrusions of Devonian granitoids. Four vein types pre-date Acadian folding. Five gold-deficient vein types are associated with Acadian folding (syndeformation); whereas two gold-deficient vein types clearly post-date this deformational event: Previously unreported, wall rock alteration is associated with early crosscutting and semiconcordant auriferous veins. In contrast, early stratiform veins are devoid of wallrock alteration. It is suggested that the auriferous vein arrays formed as submarine exhalitive systems over synsedimentary tensional faults and that the Meguma domain may represent the opening of a basin similar to the modernGuaymas rift .IntroductionThe term ""turbidite-hosted gold deposits"" is introduced to distinguish gold deposits contained within a turbiditic sequence of wackes and shales (or their metamorphosed equivalents) from gold deposits in other types of sediments. Usage and justification for the term is similar to ""carbonate-hosted lead-zinc deposits"" or ""volcanogenic massive sulphides"". A range of different characteristics can be present in individual deposits, some of which may be indicative of specific deposit types in the same manner that volcanogenic massive sulphides can be subdivided into ""Cyprus type"", ""Kuroko type"", ""Besshi type"", etc. Historically, gold deposits hosted by turbiditic flysch were an important class of quartz-vein gold mines in the 19th century. They included the goldfields of Victoria, Australia, Otago, New Zealand and Nova Scotia, Canada. Production from most of these fields had ceased by World War II and interest in this type of deposit waned. However, the recent exploration interest in gold has resulted in both re-assessment of the classical mining camps and the discovery that ""turbidite-hosted"" gold deposits are present in many parts of the world.Mapping of the regional geology and gold deposits of the Megumadomain of Nova Scotia was carried out by E.R. Faribault of the Geological Survey of Canada between 1886 and 1939. Faribault produced a comprehensive series of maps and reports for each gold district, a compendium of which was published by Malcolm (1929)."

Jan 1, 1987

The reality of rising electrical power costs and the haunting prospect of decreasing electrical power availability are a threat to the growth of new projects and expansion programmes that could negatively affect the sustainability of mining operations. These threats require the adoption of effective power saving measures aimed at three principal objectives: the elimination of wastage, the reduction of power usage particularly during peak demand periods and, more importantly, improving the efficiency of high power-demand processes. It is reasonable to assume that the greatest impact will be achieved by concentrating on those processes that are large electrical power consumers. For Anglo Platinum operations, mine ventilation and, currently to a lesser extent, mine cooling are two continuous processes that fall in this category. It is estimated that these may consume fifteen to thirty-five per cent of the power delivered to the shaft head-depending on the shaft's design. Mine ventilation systems suffer from inherent, historical inefficiencies that lead to excessive power consumption. Air cooling systems are designed to be energy-wise in terms of modulating refrigeration plant operation to meet the underground requirements while maximizing use of 'free' cooling from surface conditions. Currently about ninety-five per cent of the refrigeration capacity used in Anglo Platinum mines is dedicated to surface bulk air coolers. The net thermal efficiency of these systems is compromised as mines expand in depth and on strike. Looking to the future, this practice will be complemented by more energy demanding underground cooling tactics requiring considerably higher electrical power consumption per unit ton produced. To counter this increase in power consumption, more energy-efficient systems and advantageous transient strategies such as thermal storage and the use of ice-on surface and possibly even underground-are being considered. This paper describes work currently undertaken and planned by Anglo Platinum operations to reduce power consumption by main fans during off-shift periods, the associated efforts currently introduced to reduce underground air leakage, the possibility of introducing more efficient auxiliary ventilation systems, the feasibility of thermal storage, and a brief look at energy recovery system as a means of countering the anticipated power demand associated with underground cooling. Keywords Mine ventilation, mine air cooling, energy efficiency, chilled service water, energy recovery, air wastage, fan selection.

Jan 1, 2011

By J. O. Merritt

The primary objective of this research program was to recommend ranges of minimum luminance for safety in underground metal and nonmetal mining. Visual tasks critical to safety were identified and rank-ordered. Realistic, full-scale, dynamic task simulations encompassing the most important visual components of the critical tasks were installed in a large simulated workspace. Five trained observers performed the six simulated mining tasks under varying levels of luminance. Over 13,000 measurements of visual task performance were used in developing minimum luminance recommendations for the on-foot underground worker and the mobile equipment operator.

Jan 1, 1983

Standard petrographic profiles for many Permian seams from New South Wales and Queensland have been drawn up. The standard profiles of seams of the same age and from one or more coalfields were used to compile an idealized or type seam sequence for those coals in which more than half the seam profiles were similar to one another. A marked similarity existed between at least 7 of the 10 type seam sequences formed.The configurations of the vitrite-plus-clarite contents of the plies of 95 per cent of the seams could be formed from different arrangements of 3 basic sequences. These were...

Jan 1, 1970

By Dhananjaya Senapati, E. V. S. Uma Maheswar, C. R. Ray

Carbothermic process of Ferro Silicon production is primarily a slag-less process. However, slag formation is observed in the regular operation as experienced by almost all the Ferro Silicon Producers in different pro-portions. The problem of slagging in the furnaces may be due to: a)Variation in the input burden charge material quality b)Fluctuations in the Carbon balance and/or c)Fluctuations in the Electrode penetrations The problem will be more severe in nature with the increase of the size of the furnace. The operation performance of the furnace gets badly affected if the slag formed in the furnace is not removed from the bath in time and to the maximum extent possible. It is, therefore, very essential to know the characteristics of the slag formed in the Ferro Silicon Furnaces, besides eliminating the very cause of formation itself; and to find the routes of draining of the same from the furnace bath effectively. This paper envisages the effects of using the LIME STONE in the Ferro Silicon Burden in stabilizing the 48MVA Furnace for improved performance and better consistency. Quality fluctuations in the available Raw Materials are compared with that of the requirements for the Ferro Silicon production. The furnace operational data is compared for 12 months period each for the period corresponding to the before and after usage of lime stone in the burden and found encouraging results in the performance. Implications of use of Lime Stone in the burden on the quality of the output alloy are also studied.

Jan 1, 2007