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By Hassan El-Shall, Ayman El-Midany, Patrick Zhang

Bench and pilot scale testing results suggest that significant improvement in dewatering characteristics of fine particles could be obtained by the addition of fibrous materials. Case studies involving flocculation and dewatering of wastes from phosphate, bauxite, and kaolin processing plants are presented in this paper. Several dewatering techniques were investigated, including sedimentation thickening, filtration, centrifugation, dewatering on screens, and seepage-induced dewatering and consolidation. Advantages and limitations of commercial application of some of the developed techniques arc discussed.

Jan 1, 2004

By David Penswick

Despite anecdotal evidence to the contrary, the mining industry is not in decline. Rather, the world?s largest mining companies are among the most consistently profitable companies in any industry. In many cases, profitable mining companies have been built around a few large scale, long life mines. These criteria for success ? size and long life ? have led to the current preference for deposits that can be exploited using open pit methods. However, developments in the science of block caving have resulted in this mining method achieving costs and productivities that are competitive with the largest open pits, while achieving widespread applicability. One implication of the low costs and widespread applicability of block caving is that some current open pits are possibly too deep.

May 1, 2003

By S. A. L. Read

"The intact rock constant, mi, is one of the three basic input parameters required for the widelyused Hoek-Brown failure criterion. Values for the constant should ideally be determined by statistical analysis of laboratory test data. In this paper the influence of the inclusion or exclusion of tensile test data on derived values is discussed. We firstly investigate the relationship between direct tensile strength (DTS) test values and Brazilian tensile strength (BTS) test values based on a literature search, finding that the correlation between the two test types is DTS = 0.9*BTS, independent of the lithology being tested. Secondly, using the shear strength database of Douglas (2002), we examine the influence of confining pressure range and the inclusion or exclusion of DTS and BTS test values on calculated values of mi.Chief amongst the influences was the exclusion of tensile data in the calculation procedure, particularly when the Hoek triaxial confining stress range requirement (?3?max = 0.5?c) was not satisfied. Based on a reasonable 1:1 relationship between R (the ratio of unconfined compressive to tensile strength), use of actual tensile data in the calculations for the Hoek brown failure criterion is considered to be a simpler and more robust approach to the use of a tensile cutoff based on empirical criteria such as that of Fairhurst (1964). We advocate the fitting a failure curve using compressive and tensile test data as the most reliable means of calculating mi, while at the same time satisfying requirements as originally advocated by Hoek relating to the appropriate triaxial confining stress range (?3?max = 0.5?c) and sufficient (>5) evenlyspread data points. In the absence of triaxial data the use of R provides a practical means of obtaining estimates of mi that are more robust than guideline values."

Jan 1, 2015

By S. M. C. Santos

Preliminary bench-scale studies were carried out on the leaching of a zinc sulphide concentrate from Somincor, Portugal, and the purification of the resulting pregnant solution using solvent extraction techniques. The sulphide concentrate contained 36% Zn, 36% S, 2% Fe and 4% Cu. The leaching was carried out with sulphuric acid in the presence of ferric sulphate as the oxidant. Important leaching parameters, such as the effect of reaction time, the solid-liquid ratio, temperature and concentrations of acid and oxidant, were investigated. After leaching, the recovered solution was contacted with an organic phase containing Acorga 5640 to remove the copper. Subsequently, the removal of iron from the leaching solution was achieved with a mixture of Cyanex 272 and TBP. This solvent mixture was relatively selective for iron over zinc. The stripping of the loaded solvent was performed with 200 g/L H2SO4. Six countercurrent extraction stages achieved a separation of about 99% of the iron from the leaching solution. The iron-free leachate can be further treated to recover minor metals by cementation, and finally, zinc by liquid-liquid extraction. The advantages of the suggested process relative to the traditional jarosite process are discussed.

Jan 1, 2006

By N. T. Oo, L. D. Hutton

"The Banora Point Upgrade Project is a 2.5km long six-lane divided freeway in northern New South Wales, Australia. The geology at the project area comprises a volcanic succession of variably weathered basalt flows and agglomerate deposits that reach 48m in thickness and overlie Mesozoic sedimentary rocks. A site specific rock classification system was developed that characterised all the rock units based on the engineering properties governing the rock mass behaviour i.e. intact rock strength and defect characteristics (spacing, aperture, infilling, wall roughness and weathering) irrespective of the geological origin. This approach simplified the design and the on-site verification processes. Based on this classification system, rigorous quantitative statistical assessments of the available geological information including various laboratory and field testing were performed to derive the geotechnical design parameters for various rock classes. These parameters were used to complete geotechnical designs of retaining wall systems. INTRODUCTIONThe Banora Point Upgrade Project is a 2.5km long six-lane divided freeway in northern New South Wales, Australia. The key features include two interchanges, a 300m long viaduct, a large cutting through Sexton Hill with an associated 100m wide Land Bridge and retaining walls reaching 490m long and up to 22m high. This paper focuses on the derivation of representative geotechnical parameters for geotechnical design of the retaining structures supporting Sexton Hill Cutting including bored pile retaining walls and soil nail walls. The geology at the project area comprises a volcanic succession of variably weathered basalt flows and agglomerate deposits that reach 48m in thickness and overlie Mesozoic sedimentary rocks. Due to the complex geological nature of the site, an understanding of the regional and local geology, the typical behaviour of individual geological units and the implication of onsite variations from design intention are the ultimate challenges to the geotechnical engineer in order to select representative geotechnical parameters for design."

Jan 1, 2015

By Peter Moser, Thoma Oberndorfer

"Within the research project “Mine Development” (Fettweis and Moser, 1990) a PC-based mine database has been built up since 1991 and so far includes detailed technical and economic data of about 150 under-ground hardrock mines in industrialized countries worldwide. These data represent about 50% of the underground hardrock mines in west and central Europe, Scandinavia, United States, Canada and Australia (Fig. 1). The mining operations included in the database have been visited directly and analyzed with respect to their deposit conditions, their general design and layout and also their operational and economic performance.The main aim of the Mine Database is to make a contribution to an improved planning of new underground hardrock mines. An analysis of current mine planning practices shows, that both personnel and company experience is still a dominant factor in planning new underground hardrock operations. Through the information included in the Mine Database the experience of a single per-son or company is supplemented by the experience of a wider group of people. The Mine Database makes the huge amount of experience that is available worldwide in the field of under-ground mining accessible for new mining projects. From that a contribution to a more reliable mine planning procedure based on the performance of existing mining operations is expected.In addition to its use in planning new mining operations, the Mine Database can con-tribute to the exchange of technical data among different mining operations, especially on equipment performance, etc. Such an information service is offered by the Department of Mining Engineering & Mineral Economics in Leoben and is already being used by different mining companies. To respect proprietory information, company specific information is not released under any circumstances.The cost of building up the Mine Database, so far, is about US$500.000 — two thirds of which is labour, and one third, travel."

Jan 1, 1996

By M. A. F. Fedikow, D. A. Baldwin, C. Taylor

The Agassiz Metallotect and the Johnson Shear Zone represent two metallogenetic fea tures located within the northern and outhern belts, respectively. of the Aphebian-aged Lynn Lake greenstone belt in northern Manitoba . Numerous gold occu rrences are associated with these two regional features . The tratabound Agas iz Au-Ag deposit with 2.9 million tonnes of 5.2 g/tonne Au and 11.8 g/tonne Ag. occurs within the Agassiz Metallotect. The stratigraphic sequence characterizing the Agassiz Metallotect comprises interlayered ox ide. silicate and sulphide facies iron formations, biotite-rich and siliceous siltstones. and a high Mg- i-Cr basaltic rock that ha previou ly been identified as tholei itic picrite. These rocks can be traced in outcrop and by their INPUT and gradiometric signature for 65 km. The Johnson Shear Zone is an ill-defined 35 km long zone of strucwral disruption that crosscuts volcanic. sedimentary and intrusive rocks and contains numerous vein-type gold occurrences. Both of these metallotects are characterized by their low level of exploration activity and as a result offer excellent residual exploration potential. Rock, basal till and vegetation geochemical techniques applied in the vicinity of the Agassiz deposit indicate the presence of trace element dispersion halos associated with the mineralization. The halos define an exploration target larger than the mineralized zone. Gold occurrences within the two metallotects are described with emphasis on the Agassiz Au-Ag deposit . A wide range of gold occurrence-types is documented including syngencticstratabound , epigenetic-replacement and epigenetic-quartz vein .

Jan 1, 1986

By H. C. Gunning

DURING the past year the Cadillac-Malanie area in northwestern Quebec has been catapulted to the front as one of Canada's most active gold mining districts. Late in 1934 the area was lolling along in the doldrums, with one producing mine and a handful of active prospects. 1935 passed with only slightly increased activity, but saw the start of production at Canadian Malartic mine. Lightning struck in April, 1936, when a new and phenomenally rich ore-body was found in O'Brien Gold mine, and by midsummer the camp was ablaze with activity. An important new discovery on the Pan-Canadian property, and pleasing underground developments at Sladen Malarric, East Malartic, and Lapa Cadillac, in addition to other new developments, lent fodder to the flame, and at present several dozen properties are being actively developed. For the past three seasons, the Geological Survey of Canada has been engaged in a fairly detailed study of the geology and mineral deposits across Cadillac, Malarric, and Fourniere townships. Ir is the purpose of this paper to present a brief preliminary statement of the structural and economic geology and to discuss some of the more important problems that have been found to exist. The reader is requested to remember that the paper is a preliminary one and that therefore the conclusions presented are open to revision. It is impossible to make full acknowledgment for help received, for the writers are indebted to practically every operator and prospector in the area for generous co-operation in the work, and to several private, provincial, and federal geologists for data and frank discussion of problems encountered. Over a score of student assistants from McGill, Queen's, and Toronto have given excellent service. Published reports by Wilson, Cooke, James, Mawdsley, L. V. Bell, and J. J. O'Neill greatly facilitated the work. For adequate control surveys and a topographic base-map, the writers are greatly indebted to H. N. Spence.

Jan 1, 1937

By S. Klemmer

Potential problems associated with groundwater inflows are a major concern to many Saskatchewan mining operations. Rock mass behaviour and stability have been linked to groundwater inflow potential. An estimate of the hydraulic conductivity of the rock mass is an important factor for assessing groundwater inflow potential. This paper presents a procedure that was developed to conduct air permeability tests, for estimating the hydraulic conductivity of the rock mass. Tests were conducted near underground excavations with the goal of assessing links between measured air permeability, rock mass classification and the rock mass response to adjacent excavations. Measured changes in air permeability corresponding to the distance from excavation boundaries may indicate changes to joint properties such as joint aperture, continuity and frequency. This study outlines the instrumentation, the experimental and analytical procedures, and the preliminary results from testing.

Nov 1, 2011

By Michael DeLallo

Clean Coal Technology (CCT) ?Technologies designed to enhance both the efficiency and the environmental acceptability of coal extraction, preparation and use?. These technologies reduce emissions, reduce wastes, and increase the amount of energy gained form each ton of coal extracted and converted into energy. ?? Carbon Capture and Sequestration are an integral part of CCT either as constructed or on a future retrofit basis.

May 1, 2008

By B. Tiryaki, M. Ayhan, O. Z. Hekimoglu

Coal shearers are one of the major sources of dust and fines in underground coal mines. Despite considerable research investigations, no comprehensive in situ investigations coupled with extensive laboratory studies on the effects of drum design on generation of dust and fines have been found. It may be for this reason that many major shearer drum manufacturers persistently employ a certain drum-lacing pattern on current coal shearers, which is believed to cause excessive dust and fines in coal mines. This paper shows how respirable dust and fines are minimized under near-identical conditions when the drum lacing pattern was changed from a triple-tracking to a single tracking arrangement. A series of laboratory trials simulating in full scale the practical cutting action of tools was followed by extensive long-term underground trials during production operations in OAL (Cayirhan) Lignite mine in Turkey. The results are presented and discussed, and recommendations for proper drum-lacing in terms of respirable dust and fines are made.

Jan 1, 2002

By N. J. Contini, R. W. Knopp

"In March 1988, old Denver flotation cells were removed from Dickenson's Arthur w. White Mill, and a new flotation circuit, consisting of four Prochem rougher cells and a Hydrochem agitated cleaner column, was commissioned. The refractory portion of the gold in the ore is associated with arsenopyrite, therefore the flotation circuit is set up to produce a saleable sulphide concentrate. Tailings from the leach circuit are conditioned prior to being pumped as feed to the flotation circuit. The prototype Hydrochem agitated column has been in operation as a single cleaner stage for rougher concentrate. The effect of flotation circuit changes on gold recovery data, as well as cleaner concentrate production, and development work to achieve the target results, have been investigated. Flowsheet modifications and the resulting circuit performance data, along with test results to date, will be presented.INTRODUCTIONThe mill is capable of treating 1000 stpd of ore averaging approximately 0.30 oz/ton Au. The ore is crushed and ground to 75% - 200 mesh. Gravity concentration, cyanidation, and Merrill - Crowe precipitation yields 84% gold recovery. Detailed descriptions of the comminution, gravity separation, and leaching circuits, as well as background information have been presented elsewhere (Suttill, Van Weert et al). The target cleaner concentrate grade is 1.0 oz/ton Au for custom smelting and refining. Historical gold recovery values of the old circuit was approximately 20% of the gold present in the float feed at the target grade. The recovery value objective set for the new circuit during the planning stages was 50% of the gold present in the flotation feed at 1.0 oz/ton Au in cleaner concentrate."

Jan 1, 1989

By James McManus

The original analogue instrumentation at Lornex Mining Corporation to optimize the throughput by controlling the power drawn by the semi-autogenous mills was found to be inadequate because of the frequent changes in ore type. Although the trunnion bearing pressure of the mill was a crucial control criterion, it was not utilized in the original control scheme. After several plant tests of different types of analogue controllers were unsuccessful in finding any control equipment suitable for this application, it was concluded that a digital process control computer was required. Computer control strategy to optimize the grinding rate by controlling the power and the bearing pressure of the semi-autogenous mill was developed and a Fox 2 /30 computer made by Foxboro was selected. After six months of experimentation, it was found that the throughput was increased substantially by computer control.

Jan 1, 1978

By J. Boldy

This paper is an attempt to place Canadian Precambrian volcanogenic deposits in perspective, by examining and compiling data regarding certain neglected fundamentals of size, grade, value, frequency distribution and spatial density. The discovery roles played by various exploration methods are compared and contrasted, and. using empirical methods, the probabilities of discovery are discussed, combined with the use of an effective 'cost-per-target' program. From these basic observations, realistic exploration judgments may be made. Using similar methodology, this format may be applied to other types of deposits. Precambrian volcanogenic deposits occur in a natural geometric progression in size. They number 110, of which 70% are pre-producers, producers or past-producers. These deposits are bonanzas and generally have a 'net pre-smelter' value of between $43 and $62 per ton. The statistically typical deposit is that which occupies the modal position, has 400,000 tons of ore, a value of $20 million and occurs with a frequency of 40%. A median deposit has 1.4 million tons of ore, a value of $70 million and occurs with a frequency of 15%. An upper-decile deposit ha s 13.3 million tons of ore. a value of $750 million and occurs with a frequency of 6.5%. The major, mid-upper-decile deposits have a minimum of 50 million tons of ore, a value of $3 billion and occur with a frequency of 4%. Five major volcanogenic deposits occur in the Precambrian and account for 54% of production. This contrasts with 55 deposits (all below the median) which account for 3.9% of production.

Jan 1, 1977

By Rejean Gagnon, Fernand Rochefort

"Haulage costs, in most operations, represent a large portion of total cost. Quebec Cartier Mining Company came to the conclusion t hat an electric trolley assist providing more horsepower than available from dieselgenerator sets presented the best oppor tunity for improvement. Accordingly, a testing and development program was carried out which resulted in the design, installat ion and application of a practical system. This paper describes the development of the system, the equipment used as well as the actual operation. A projection is also made to indicate further improvement in productivity. A comparison is made of truck operating data before and after activation of the trolley assist system in order to determine its economic impact."

Jan 1, 1972

By L. Li

Backfill is increasingly used in underground mines, as it can help reduce the environmental impact from mining operations. However, the primary objective of backfilling is to provide safe working space for miners, by improving ground stability conditions. As cement is often added to the backfill, a critical issue is the determination of the required backfill strength (cohesion) due to the binder. This value is usually obtained from a solution proposed by Mitchell and co-workers, in the early 1980?s, for stopes with an exposed backfill face. This paper presents a brief review of the Mitchell et al. solution, with some of its main limitations. Some of the recently developed solutions for backfill design are then summarized and discussed.

Aug 1, 2013

By Q. H. Bui

The elastoplastic self-consistent model is one of the effective models to study the initial microstructure effect on the mechanical behavior of bulk materials. However, the use of this micromechanics-based model which takes into account only the Hall-Petch relationship at grain level for predicting the grain sized effects on the strength of the deformed materials is not accurate yet because of the fact that the dislocation density contributes also to the strengthening of this kind of materials. In this study, a modification made to the Hill-Hutchinson elastoplastic self-consistent model was proposed for investigating the microstructure dependence of the mechanical behavior of cold-drawn 6063 aluminium tubes. Because of the novel modification, an estimation procedure with two steps was required to identify the parameters of this micromechanical model. An acceptable agreement between experimental and theoretical stress-strain curves was achieved.

Jan 1, 2011

By Charles Amoah

Abosso Goldfields Limited has been optimizing the comminution circuit at the Damang Mine Operation for the treatment of 100% primary ore. The optimization process started at a base rate of 343 tph when treating primary crushed primary ore, and was increased to above 600 tph with partially crushed primary ore. Abosso Goldfields engaged Orway Mineral Consultants (OMC) to assist with the optimization process in 2009 and the two companies have been working together since, to further refine the process. Continuous improvement was achieved through crushing circuit modifications, changes in operating processes and grinding control system utilization. This paper discusses the improvements developed for the increase in milling capacity and improvements in final product size.

Jan 1, 2012

By F. E. Goodwin

Since the last CIM Zinc and Lead Conference ten years ago, significant technical and market forces have influenced how these metals are used, and the geographic distribution of their uses. Unprecedented price fluctuations have opened competitiveness issues, while the rapid growth of the Chinese market has created challenges both inside and outside China. Recent technical developments in battery energy storage, coatings, castings and chemical applications of lead and zinc will be reviewed together with the influence of these trends on end use markets.

Jan 1, 2008

By C. M. Bartley

Fluorspar, in addition to its familiar uses as a metallurgical flux and as a source of the electrolyte for aluminum production, has become important as an essential raw material in the rapidly growing fluorine chemical industry. The unique ability of fluorine to react and form compounds with al-most all other chemicals has made it one of the important elements in modern chemistry. Research and development over the past thirty years have resulted in a current annual production of fluorine chemicals that is both technically and economically important to industry. Because many of these chemicals and products are relatively new, and most have properties that are not duplicated by other materials, the present uses are expanding rapidly and new applications are being reported continually. Fluorspar, the only immediate and practical source of fluorine, is therefore an important mineral. This fact has been recognized in major industrial areas such as the United States and Western Europe, but has received little attention in Canada.

Jan 1, 1962