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By George B. Clark, Edward E. Hornsey

Pulses from large underground explosions which traverse the rock beyond the "fracture" and "plastic" zones do not behave as a spherical elastic model. Observed attenuation is greater than that predicted by the elastic wave equation, and the pulse form changes in a different manner, i.e., it usually lengthens with the first power of the distance. To more clearly define a mathematical real earth-wave model, detailed analyses of the spherical elastic and the Voigt viscoelastic models have been made, and results compared with observed wave forms from large confined chemical and nuclear explosions. TRANSIENT SPHERICAL ELASTIC WAVES Scope of Investigation Transient elastic spherical waves were investigated in detail. However, an elastic model is not, in general, an exact representation of wave propagation in rock. An understanding of transient elastic waves is desirable for gaining insight into explosive-generated wave phenomena because it can be employed for comparison of more complex and realistic models, such as the Voigt model, or others which may simulate real earth waves. The study was concentrated primarily on the peak values of the radial wave parameters : displacement, particle velocity, acceleration, stress, and strain.

Jan 1, 1972

By Chris Brothen

The introduction of new technology in mine operations has provided real opportunities for increased efficiencies and production gains which translate into enhanced profits. Computing and network technology usage has become integrated into surface mining operations and on average these investments in technology have proven beneficial for efficiency and productivity improvements. Embracing new technologies however, does not guarantee positive results. The expectations or improvements derived through the technology must be confirmed and clarified well before implementation. Tire Pressure and Temperature Monitoring Systems are an excellent example of an existing technology that can provide full time automated performance measurements of tires operating under harsh conditions and environments. Prompt warnings or alarms signaling when a tire has exceeded operating capacities will provide savings through lowered maintenance costs and increased productivity. To truly quantify the projected savings in tire life, fuel consumption, and increased levels of production, all costs associated with the technology, both direct and indirect must be considered. Apart from the initial cost of the system implementation, ongoing maintenance and support costs must be considered as well as the costs of system integration into existing mine operations

May 1, 2008

By Charles L. Kimbell

The final tables of this chapter, tables 25-50, extend and expand the statistical series on production that was started in the 1963 edition of the Area Reports: International Volume of the Minerals Yearbook and that was subsequently updated and expanded in the 1965 and 1967-90 editions. Continuing the practice started in 1989, a column has been included in each of these tables providing a 5-year average for 1987-91, inclusive. This should provide a clearer picture more rapidly of the role of each major producer over the 5-year period. The listing order of major producers, however, continued to be, as in past years, in descending order of rank in the year of review, 1991. This group of tables now includes each of the crude minerals that ranked from? 1st to 19th in 1983 terms of value of their output (as well as four others of lesser rank). These 23 crude mineral commodities accounted for 93 % of the estimated value of world crude mineral production in 1983. In addition, world output of five key downstream products-aluminum, steel, cement, nitrogen in ammonia, and refined oil-is included because of their significance as products.

Jan 1, 1993

By Keith Heasley

An eastern longwall mine was required to mine through a set of three entries located midway down the length of a panel. Of course, the mine desired to design a successful support system for the mine-through area at the least cost. To further complicate the design process, the mine-through entries were located directly under the end of a previously mined, overlying longwall panel and the entries were close enough to be subject to stress interactions from the overlying seam. In order to accurately evaluate the multiple-seam stresses and modify the mine-through support system appropriately, the boundary element program LaModel was used to model the stress and displacements in the two mines. Using the results of the model's stress analysis, the support density was systematically varied throughout the mine- through entries for optimum sup@ efficiency and economics. During the actual mining of the cross panel entries, the longwall experienced few, if any, additional delays, and overall, the support and mine through of the cross-panel en- tries at Harris #1 was very successful, saving the mine confineable time and money.

Jan 1, 2003

By J L. Kanau

In this study some drawbacks of using Bond grindability as a measure of grindability characteristics for mill control have been discussed. After reviewing the merits of alternative methods of determining the Bond grindability published in the literature, a new alternative method has been proposed.

Jan 1, 2000

By K. Hanumantha Rao, K. S. E. Forssberg, H. R. Manouchehri

This paper summarizes the practical considerations of the various electrical separation methods used in mineral processing. The effective factors related to mineral characteristics and equipment attributes are described and analyzed with reference to conventional industrial applications of the electrical methods. Some new aspects of electrical methods application and their potential for mineral beneficiation, apart from the mineral systems that have been successfully beneficiated, are also presented. In addition, wet dielectric separation, which now appears to be promising, is briefly cited.

Jan 1, 2000

By Timothy F. McConachy

Hydrothermal fluids emanating from the seafloor rise as buoyant plumes, entraining ambient bottom sea water on the way up, until they reach density equilibrium and spread laterally in a direction that is governed by near-bottom currents. Plumes provide targets for focussing exploration for seafloor polymetallic sulfide deposits associated with active hydrothermal vents because their lateral and vertical extent is commonly orders of magnitude larger than the vent field from which they originate. Black smokers can inject on the order of 10,000 µg of particles per liter into a sea water column that normally contains only about 10 µg of particles per liter. The resulting plume should be characterized by increased particulate concentration with respect to background sea water and, therefore, provide a measurable gradient towards the source of venting. By utilizing the ability of particles to scatter light, we employed a real¬time, acoustically telemetered, nephelometer to measure this gradient, and mapped the size, shape and particle concentration of plumes at an active spreading center on the Southern Explorer Ridge at lat 49°45.6'N and long 130°16.2'W. Isopach and particle concentration data indicate the presence of two separate but overlapping plumes. The first is associated with a known vent field called Magic Mountain; the second with a new field called AGOR 171, 1.2

Jan 1, 1986

On the basis of investigations carried out, the author offered new technology, which allows utilising all titanium-contained waste with receiving of finished products: catalysts for utilisation of hydrogen sulfide gases, accompanying oil-extraction. This technology is presented in the paper. It is economically effective and ecologically clean.

Jan 1, 2003

By M G. Aylmore

Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver complexes, and readily leaches gold ores in ammoniacal solutions, catalysed by Cu(II). It is particularly suited to carbonaceous ores where the recovery of gold by cyanide is poor. However research over the past 20 years has identified a number of issues and impediments that must be understood or overcome before an overall process can be demonstrated as practical and economic for typical oxidised gold ores. This paper reviews our current understanding of thiosulphate chemistry and mechanism of gold dissolution, and discusses the stability of thiosulphate and polythionates. It then reviews the results of leaching various gold ores that have been reported in the literature, discusses gold recovery options, and considers environmental and toxicity issues. Some of the issues that require further research include decreasing the oxidation of thiosulphate by Cu(II) or other oxidants, increasing the extraction of gold compared to cyanide, and understanding the variation in gold recovery between ores. More work is also required to minimise the effect of polythionates on gold recovery using resins or alternative absorbents, to improve the elution of copper and gold from resins, and to recycle or minimise the concentration of reagents.

Jan 1, 2002

By Charles L. Kimbell

The final 26 tables of this chapter, tables 25-50, extend and expand the statistical series on production that was started in the 1963 edition of the "Area Reports: International" volume of the "Minerals Yearbook" and that was subsequently updated and expanded in the 1965 and 1967-89 editions. Continuing the practice started in 1989, a column has been included in each of these tables providing a 5-year average for 1986-90, inclusive. This should provide a clearer picture more rapidly of the role of each major producer over the 5-year period. The listing order of major producers, however, continued to be, as in past years, in descending order of rank in the year of review, 1990. With the inclusion of silver and uranium in the 1988 edition of this chapter, this group of tables now includes each of the crude minerals that ranked from 1st to 19th in 1983 terms of value of their output (as well as four others of lesser rank). These 23 crude mineral commodities accounted for 93% of the estimated value of world crude mineral production in 1983. In addition, world output of five key downstream products-aluminum, steel, cement, nitrogen in ammonia, and refined oil-are included because of their significance as products.

Jan 1, 1993

By Sergey G. Pushkin, Eugeny L. Schastlivtsev, Anatoly A. Bykov

Three years ago the authors and a group of assistants began to develop a GIs-system for integration of comprehensive eco- logical information to be linked to geographical maps of Kuzbass region. And now we have got the working system and some first results that the present paper deals with.

Jan 1, 1996

By C. W. Spencer, J. T. Smith

GRAIN-BOUNDARY surfaces are penetrated by a liquid phase when the liquid-solid interfacial tension is less than one-half the tension of the grain-boundary surfaces. Grain growth may occur in the presence of this liquid phase. burke1 reports that grain growth of this nature has been observed in two-phase ceramic systems. He suggests that the presence of a grain-boundary liquid may accelerate or decelerate the

Jan 1, 1963

In 2004, a total of 741 nonmetal mining operations reported employment to the Mine Safety and Health Administration (MSHA). These mines (e.g., potash, gypsum, salt) comprised 5.1% of all operations.

Sep 1, 2007

By K. N. Han, N. S. Kim, H. Yoon, J. S. Sohn

The leaching behavior of silver and silver oxides in ammonical solutions has been studied. The current study is concerned with an effective recovery of silver from secondary sources such as spent silver batteries. Silver associated with these batteries appears in various forms including metallic silver, argentous oxide, Ag2O and argentic oxide, AgO. The leaching behavior of metallic silver in ammoniacal solution has been studied using an electrochemical mehtod. Oxidants used in this study include hyperchlorite, hydrogen peroxide, bromine and iodine. Results on cyclic polarization and Tafel plots on the silver anode in ammoniacal solutions are presented and the results are discussed. The dissolution rate of metallic silver in ammoniacal solutions is also compared with those of silver oxides.

Jan 1, 2002

By A. J. Vivyurka

"This is a talk about the experiences that Rio Algom Mines Ltd. has had in the Elliot Lake uranium area trying to make the tailings more compatible with the surrounding environment. To get a better idea of the problem that we are associated with we have to go back to the location. The Elliot Lake uranium area is situated about half way between Sault Ste Marie and Sudbury and is about 20 miles north of Lake Huron. In 1950, uranium was discovered along the north shore of Lake Huron and by 1961 we had up to 9 mines operating in the area. Then the United States Atomic Energy Connnission withdrew their contracts so that at present there are only 2 mines operating. From all the mines that we had operating, we ended up with 7 tailings areas. From these 7 tailings areas we have 5 sites where we have active treatment or rehabilitation. There is the Pronto site where we are treating uranium tailings and copper tailings. There is the Lacnor-Nordic site which is located just out of Ellio Lake. The Milliken-Stanleigh site is in the Crotch Lake area. The Panel tailings is off the north end of Quirke Lake and finally there is the operating property of Rio Algom Mines at Quirke Lake.To understand fully the problem with this rehabilitation we have to look at the constituents of the ore. The ore body is a quartz conglomerate with uraninite and brannerite as the uranium bearing minerals in a fine ground mass of quartz, sericite and pyrite which separates the larger quartz pebbles. The approximate composition of the ore is: 80% quartz, 13% chlorite, 7% pyrite and 0.2% uranium minerals. The processing method also adds a few constituents to the final tailings."

Jan 1, 1975

By B. Mienie, J. F. Morrison, C. H. Wyndham, M. J. Martinson, N. B. Strydom

Contribution to discussion M. J. Martinson (Associate Member)*: Application of the simple selection test mentioned in the penultimate paragraph of the paper (reference to a more detailed description of the test would not have been inappropriate) should assist South African mining engineers to make more efficient and possibly more humane use of available labour. The authors mention that the test 'is in use in the gold mining industry', and it would be interesting to know the extent of this usage in terms either of number of mines or as a percentage of the total number of labourers employed on 'heavy' tasks. The paper would have been of greater interest had the authors attempted to relate their findings to the statistics of labour usage in gold mines, members of the Chamber, and to the 'heavy' tasks in particular. On this the authors confine themselves in their Introduction to the somewhat ambiguous statement that 'A relatively high proportion of the 360,000 Bantu mine labourers are employed underground on manual tasks'. To appreciate the practical significance of the authors' work one needs a detailed breakdown of the underground labour force by occupations, together with estimates of quantities such as: (a) total stope and development tonnages moved manually per shift: by shovelling by shovel/tram by tramming together with distances and any other relevant data; (b) theoretical energy expenditures required to accomplish (a); (c) actual energy expenditures required to a accomplish (a); (d) energy theoretically available to accomplish (a) based on 50 per cent of the total maximum oxygen intakes of the labour force allocated to these tasks. Analyses of this sort on an industry basis might demarcate the more promising areas for detailed investigation. Stress is often laid on the need for increased mechanisation to increase stope productivity, but it may be questioned if enough is known about the characteristics, performance and potential of our underground labour force to warrant blind acceptance of stope mechanization as the industry's panacea. Provided that health and safety are not compromised, the ultimate yardstick for assessing any form of stoping is profitability; obviously the industry must investigate very thoroughly any form of mechanization which might reasonably be expected to increase profitability, but it should also be remembered that a radical overhaul of existing systems-which have after all evolved by trial and error over the past 75

Jan 11, 1968

By Frederick Laist, H. J. Maguire

The ore from the Butte mines of the Anaconda company is quite siliceous; that is, it contains considerably less iron than is needed for the fluxing of the silica. The direct smelting of this ore, therefore, requires the addition of considerable fluxing material. The only flux available in sufficient quantity at Anaconda is limestone containing no metallic minerals. This necessarily makes the direct smelting of the ore so expensive that it is more profitable to subject the ore to a preliminary treatment by concentration. However, as the losses in the concentrator were very high, compared with the losses in the blast furnaccs, it was found, by calculation, more profitable to send ores containing more than a given percentage of copper to the blast furnaces, in spite of the higher costs of treatment. The dividing point was dependent on various factors, the chief of which was the prevailing market price of copper. It was customary, therefore, to segregate the ore as mined into two classes. Ore in the first class generally contained 5 per cent. or over of copper; this was sent directly to the blast-furnace department. Second-class ore contained less than 5 per cent. of copper, and averaged around 3 per cent.; it went to the concentrating department. With the introduction of the flotation process, it mas found possible to maintain an average recovery, as concentrates, of 96 per cent. At the same time, the cost of reverberatory smelting was very materially decreased by the use of pulverized coal. These two changes in practice made the blast furnaces unable to compete with the reverberatory furnaces on a cost basis. The distinction between first- and second-class ore was therefore abandoned, and the ore was treated by concentration. Obviously, on ores as high in iron as the Butte ores, the concentrator produces a product that is self-fluxing; in fact, it is possible to produce a concentrate containing more iron than is necessary to flux the silica. Under these conditions, the amount of basic fluxing materials required for the smelting operations became very srnall and the converter slag lost its former value as a blast-furnace flux. For this reason, a less expensive method of recovering the copper, silver, and gold contained in it than smelting in blast furnaces had to be found. It was not feasible

Jan 1, 1921

By Xiaoqi Sun

"Rare earth elements (REEs) have a series of specific properties making them invaluable in products including lighting, electronics and magnetism. The elements have been used in many commercial products, for example, turbines, electric vehicles, batteries, lighting, computers, cell phones and lasers. Heavy REEs are attracting the interests of scientists from many countries, and these elements have become critical to develop high-tech materials. Ion-adsorbed rare earth deposits were first discovered in China. The minerals are also called weathered crust elution-deposited rare earths. The particular types of deposits are distributed throughout southern China. The ion-adsorbed deposits are rich in medium and heavy REEs, accounting for more than 80% of the world’s total medium and heavy REEs production. However, the separation of heavy REEs from ion-adsorbed deposit is difficult owing to their similar chemical properties. The conventional separating technologies have caused serious pollution. A novel extraction strategy has been developed in this laboratory and is presented herein.INTRODUCTIONThe unique properties of rare earth elements (REEs) render them important in high-strength magnets, lighting phosphors, polishing compounds, and ceramics. Especially for applications that take advantage of the f-orbital electrons, substitutions outside the REE family are often difficult to impossible (Nassar, Du, & Graedel, 2015). Extracting and separating individual elements from mined ore is not easy, requiring lengthy operations to separate them, and this results in high costs and adverse effects on the environment. The low concentration of REE in the earth’s crust makes economic exploitation difficult (de Boer & Lammertsma, 2013) and the sustainability of the REEs separation industry has aroused considerable attention (McLellan, Corder, Golev, & Ali, 2014). To eliminate protons and break the dimmers in organic phosphonic acids or carboxylic acids, the saponification of acidic extractants by acid-base neutralization reactions are widely used in industrial REEs separation (Sun, Luo, & Dai, 2012a). The saponification procedure contributes to increased extractability and selectivity of acidic extractants to a considerable extent. The common industrial saponification mechanisms and technological processes are shown in Figure 1 and include ammonium saponification (saponified by NH3·H2O), sodium saponification (saponified by NaOH), calcium saponification (saponified by Ca(OH)2), and magnesium saponification (saponified by MgO). These inevitably result in wastewaters containing NH4 +, Na+, Ca2+ or Mg2+ because of the cation-exchange extraction mechanisms (Xiao, Long, Huang, Feng, Cui, & Wang, 2013; Song, Fu, Wang, Liu, Zhou, & Li, 2014; Sun & Waters, 2014)."

Jan 1, 2016

By Frank Calvin Roberts

An examination of the various devices employed for operating blast-furnace charging-bells has led me to design the arrangement slrown in the accompanying figure. In order to contribute to the even distribution of stock, the movement of the bell should be in a vertical line, since any tendency to side-thrust which may be in-

Jan 1, 1888

By Jack C. Stuart, Robert L. Obradovic, Allen J. Hulshizer, Anthony J. Stewart

Two deep bedrock tunnels, extending over a mile into the Atlantic Ocean, to provide the cooling water requirements for the Seabrook Station represent a major tunneling venture. This paper provides an outline and discussion of the planning and construction work associated with developing of the land riser and work shafts and the conventionally excavated tunnel station area.

Jan 1, 1979