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By T. C. Murphy, W. Taciuk

In 1966, the Iron Ore Company of Canada commissioned a wet magnetic scavanging plant for the recovery of fine magnetite values p.resent in spiral tailings discharged from a spiral gravity separation process. The plant includes dewatering, grinding, classification, thickening, mini-wedge screening, and primary, secondary and tertiary wet magnetic separation stages. The source of feed varies in quantity and quality, so the original design included variable operational procedures to deal with these conditions.

Jan 1, 1972

By Kyeong Woo Chung, Ho-Sung Yoon, Jyothi Rajesh Kumar, Chul-Joo Kim, Sung-Don Kim

The aim of the present study is to investigate the extraction, separation and recovery of the indivisible metals of dysprosium and neodymium from permanent magnets scrap leach liquor solutions with meaningful recovery. The present experimental development focused on dysprosium separation from neodymium and recovery by suitable mineral acids. Fundamental studies of the effect of time, pH and extractant concentration on the metal separation were conducted followed by proposal of a mechanism for extraction. Process development included generation of McCabe-Thiele diagrams and counter current extraction (CCE) studies. After loaded organic generation from the CCE process, this was followed by scrubbing studies as well final recovery of dysprosium.

Jan 1, 2014

By S. Kahraman, K. Develi, E. Yasar

Four hydraulic top hammers, one pneumatic top hammer, and three down-the-hole drills were observed in several rock types at quarries and highway construction sites to measure the performance data. At the same time, drill cuttings from each drill hole were collected for the determination of the coarseness index (CI), which is the sum of cumulative weight percentages of a particular size-graded sample of debris, and for the determination of median particle size (MPS), which is defined as the particle for which the quantity of particles equals 50% of the total of the cumulative distribution. After the sieve analysis was carried out on the drill cuttings in the laboratory, CI values were calculated and MPS values were obtained from the plots of cumulative undersize vs particle size. The performance data of the drills, CI values, and MPS values were analyzed using the least square regression method. It was seen that strong linear relationships usually exist between penetration rates and CI values, and penetration rates and MPS values for both top hammer drills and down-the-hole drills. Penetration rates increase linearly when increasing the CI and MPS values.

Jan 1, 2004

By M. A. Tomlinson, A. Di Feo, T. C. Cheng

"Goldcorp is evaluating the potential for economic reprocessing of historic tailings at several sites, including the Aunor A facility located in Timmins. The overall project is investigating the ability to recover value, remove sulphide minerals and alternative tailings re-deposition strategies. Desulphurization of tailings will eliminate potential acid generation while improved tailings re-deposition could reduce long-term liabilities and closure costs. Through a task-share project between CanmetMINING and Goldcorp, tailings obtained from Aunor A site have been characterized using mineral association analysis and diagnostic separation techniques. The selected tailing samples contain about 2 g/t of gold. Mineralogical analysis has identified coarse agglomerates bound with gypsum and significant free gold, confirmed by high recoveries in cyanide leach tests. However, despite no evidence of surface passivation on the minerals, conventional flotation techniques were found to be ineffective in concentrating gold or sulphides due to the high fines content and highly agglomerated particles.INTRODUCTION Aunor Mine is one of the historic mines that belongs to Porcupine Gold Mines (PGM) in Timmins, Ontario. PGM has undertaken an extensive mine closure program to remediate the legacy and closed mines with the funding supported by operating mines since 2006. Over the course of 100 years of operation in the Porcupine camp, it is estimated (Stevens et al., 2013) that about 130 million tonnes of tailings have been generated. Aunor Mine produced 2.5 million troy ounces of gold between 1940 and 1984, while processing over 7.6 million tons of ore. The original gold grade of Aunor Mine ores was about 10 g/t. With 95% gold recovery at the time, an estimate of 0.5 g/t of gold remains in the Aunor Mine tailings. Aunor Mine has two tailings impoundment areas: designated as Aunor A and Aunor B. The two sites are similar in size, about 7 hectares each. The amount of tailings in the Aunor A site alone is about 3.2 million tonnes. In 2017, bulk tailings were sampled from five designated locations in Aunor A. They were characterized using mineral association analysis and diagnostic separation techniques. The bulk tailings samples contained about 10% total sulphur, 10% iron, 2% arsenic and 2 g/t of gold. The prime objective of this collaborative work between CanmetMINING and Goldcorp is to facilitate the timely development and deployment of innovative tailings reprocessing solutions, specifically in the areas of desulphurization, and recovery of metals. This work targeted specific tailings of interest to Goldcorp which goals are to improve its environmental footprint and to reduce long-term liability. Thus, it is imperative to look for innovative reprocessing options that can overcome not only technological challenges but also achieve economic benefits to offset the costs associated with reprocessing the tailings. Moreover, the greater goal is to demonstrate and deploy tailings reprocessing solutions to solve one of the industry’s most difficult challenges for a sustainable mining industry in Canada."

Jan 1, 2019

By C. A. Jeffrey, K. Pearson

Abstract - The Croft diorite in central England belongs to a suite of Caledonian igneous rocks collectively known as the South Leicestershire diorite complex. Although the intrusions occupy separate outcrops, they are linked at depth to form a single pluton, buried beneath a cover of Triassic sediments (Le Bas, 1972; 1982, Allsop and Arthur, 1983). Both the Caledonian diorites and the overlying sub-Triassic unconformity have been affected by a complex history of alteration and mineralization which can be subdivided into four stages: (1) deuteric effects, caused by the release of volatiles during magmatic cooling; (2) albitization through sodic enrichment; (3) formation of lowtemperature laumontite, analcime and calcite veins with associated wall-rock alteration to prehnite and pumpellyite; and (4) sub-Triassic unconformity-hosted base metal, manganese and palygorskite mineralization. Zeolite mineralization occured some 200 Ma later than the intrusion itself, during post-Triassic times, as indicated by the presence of a single vein of laumontite and microcrystalline calcite which cross-cuts the sub-Triassic unconformity surface and enters the overlying Triassic sediments. Evidence from fluid inclusion work indicates that two fluids were involved in the deposition of the zeolite veins. One fluid was initially of relatively high temperature (~100°C to 320°C) and low salinity (~0.2 to 5.9 wt% NaCl equiv.), and was probably meteoric in origin, whereas the other was of relatively low temperature (~41°C to 165°C) and high salinity (~0.4 to 16.72 wt% NaCl equiv.), and is interpreted to represent a basinal brine. During Triassic rifting, thinning and fracturing of the crust, with the possible rise of associated magmas (Halliday and Mitchell, 1984), could have increased permeability and heat flow, initiating the circulation of hydrothermal fluids. Triassic unconformity-hosted base-metal mineralization in Central England is similar to other Triassic-Jurassic mineralization in Europe (Mitchell and Halliday, 1976).

Jan 1, 1997

By C. A. Jeffrey, K. Pearson

The Croft diorite in central England belongs to a suite of Caledonian igneous rocks collectively known as the South Leicestershire diorite complex. Although the intrusions occupy separate outcrops, they are linked at depth to form a single pluton, buried beneath a cover of Triassic sediments (Le Bas, 1972; 1982, Allsop and Arthur, 1983). Both the Caledonian diorites and the over-lying sub-Triassic unconformity have been affected by a complex history of alteration and mineralization which can be subdivided into four stages: (1) deuteric effects, caused by the release ofvolatiles during magmatic cooling; (2) albitization through sodic enrichment; (3) formation of low-temperature laumontite, analcime and calcite veins with associated wall-rock alteration to prehniteand pumpellyite; and (4) sub-Triassic unconformity-hosted base metal, manganese and palygorskite mineralization. Zeolite mineralization occured some 200 Ma later than the intrusion itself, duringpost-Triassic times, as indicated by the presence of a single vein of laumontite and microcrystallinecalcite which cross-cuts the sub-Triassic unconformity surface and enters the overlying Triassic sediments. Evidence from ?uid inclusion work indicates that two ?uids were involved in the deposition of the zeolite veins. One ?uid was initially of relatively high temperature (~100°C to 320°C) and lowsalinity (~0.2 to 5.9 wt% NaCl equiv.), and was probably meteoric in origin, whereas the other wasof relatively low temperature (~41°C to 165°C) and high salinity (~0.4 to 16.72 wt% NaCl equiv.),and is interpreted to represent a basinal brine. During Triassic rifting, thinning and fracturing of the crust, with the possible rise of associated magmas (Halliday and Mitchell, 1984), could have increased permeability and heat ?ow, initiating the circulation of hydrothermal ?uids. Triassic unconformity-hosted base-metal mineralization in Central England is similar to other Triassic-Juras-sic mineralization in Europe (Mitchell and Halliday, 1976).

Jan 1, 1997

By S. Castro, L. Gutiérrez, L. Uribe

"Use of lime in seawater as a pyrite depressant decreases Mo recovery in flotation of Cu- Mo sulfide ores. When technology that uses sodium metabisulfite (MBS) to depress pyrite is applied, the process is carried out at pH 6.5–7.5, the range where Mo recovery is higher than the usual pH 11.0–12.0 when lime is applied. Redox conditions and chemical reactions involved in depression mechanisms of pyrite by MBS, or sodium sulfite, in seawater are investigated and discussed based on the acidifying effect of MBS, oxidation of sulfite ions by dissolved oxygen, and the role of catalyst of some metal cations (e.g., copper ions) adsorbed on pyrite’s surface.RÉSUMÉ L’utilisation de chaux dans de l’eau de mer comme agent déprimant de la pyrite réduit la récupération de molybdène (Mo) dans la flottation de minerais sulfurés de Cu-Mo. Lorsque l’on applique la technologie utilisant du métabisulfite (MBS) de sodium comme agent déprimant de la pyrite, le procédé se fait à un pH de 6,5 à 7,5, gamme dans laquelle la récupération de Mo est supérieure au procédé habituel utilisant un pH de 11,0 à 12,0 lorsque l’on applique de la chaux. Les conditions de réduction-oxydation (redox) et les réactions chimiques impliquées dans les mécanismes de dépression de la pyrite par le MBS (ou sulfite de sodium) dans de l’eau de mer sont étudiées et débattues sur la base de l’effet acidifiant du MBS, de l’oxydation des ions sulfites par de l’oxygène dissous et du rôle de catalyseur de certains cations métalliques (par exemple les ions de cuivre) adsorbés à la surface de la pyrite. INTRODUCTIONThe copper industry is aware of the difficulties of floating Cu-Mo sulfide ores in seawater. Molybdenum recovery is partially depressed when lime is used to reject pyrite. In plant practice, sodium metabisulfite (MBS) has been demonstrated to be the most promising option for replacing lime in seawater."

Jan 1, 2017

By J. A. Morgan, P. M. Dimmell

Abstract - The Aubry pegmatites are located on the Seymour Lake property, 15 km north of Lake Nipigon in northwestern Ontario. The property lies within the Caribou Lake-Marshall Lake greenstone belt along the English River-Wabigoon subprovince boundary of the Superior province of the Canadian Shield. The property was optioned in March 2001 by Linear Resources (now Linear Gold Corp.), who carried out gridding, prospecting, geological mapping, soil and lithogeochemical sampling, trenching, channel sampling, and a total of 1,866 m of diamond drilling in 32 holes. The Aubry pegmatites are classified by Breaks et al. (2003) as complex type, spodumene-subtype, lithium-cesium-tantalum pegmatites (Cerný, 1989). These pegmatites generally form under high-pressure-low-temperature conditions, display complex internal zoning, have relatively low Nb/Ta ratios in the ore-forming assemblages, and contain significantly elevated tantalum values (Cerný, 1989). Other examples of spodumene-subtype pegmatites include the formerly producing Hugo pegmatite in South Dakota, and the currently producing Greenbushes pegmatite in Australia. The Aubry pegmatites occur as an undulating system of stacked sheets that dip moderately to steeply eastward over a 1-km strike length. The main portion of the North Aubry pegmatite ranges in true thickness from 10 to 28 m over a strike length of 125 m, whereas the thickest portion of the South Aubry has an estimated true thickness of 15 to 16 m over a minimum strike length of 95 m. The North Aubry pegmatite remains open downdip and along strike to the north, whereas the South Aubry pegmatite remains open downdip and along strike in both directions. The Aubry pegmatites are among the most highly evolved in Ontario, with the southern end of the North Aubry (trench 5/6 area) being the most highly fractionated (Breaks et al., 2002). Channel samples from the trench NA-5 area of the North Aubry pegmatite produced values up to 2.49 wt.% Ta2O5 over 4 m. Coarse manganotantalite crystals, up to 5 cm in diameter, from this trench contain up to 84.9 wt.% Ta2O5 (Breaks et al., 2002). Drill hole SL02-31 in the trench NA-6 area gave values of 0.046 wt.% Ta2O5 over 17.7 m, including 1 m @ 0.464 wt.% Ta2O5. Further exploration will focus on defining the grade of the North Aubry zone, extending and defining both known pegmatites, and identifying additional Ta-rich zones within them. Lithogeochemical and enzyme leach soil geochemical data suggest the presence of multiple undiscovered pegmatites on the property.

Jan 1, 2005

By R. H. Sheaphim

THE RECENT and continuing activity in the Boundary district, British Columbia, makes the publication of this paper timely. The following description and discussions are based on two years' experience in the district as Field Manager and Geologist for Attwood Copper Mines, Limited. The Attwood project was organized by Dr. D. F. Kidd to re-examine the Boundary mining camp. Thanks are due to Dr. Kidd, both for his intelligent guidance during the project and for his permission to publish this paper. Much of the data and many of the interpretations presented are credited to the work of, and to discussion with, Dr. W. H. White, Consultant Geologist, who worked for two field seasons on the project. However, the author assumes the responsibility for this presentation. Dr. C. D. A. Dahlstrom worked with the author during the latter stages of the project. His assistance and advice are gratefully acknowledged.

Jan 1, 1956

By T. Mulpeter, G. Deschênes

Sadiola Gold Mine is an open pit operation located in Mali and owned by Anglogold Ashanti Ltd, Iamgold Corporation and the State of Mali. A conventional cyanidation process (cyanidation/CIP) treats 15,000 tpd (of a mixture of oxide and sulphide ores) at an average grade of 3 g/t Au. In 2002, the increasing tonnage of sulphides caused an increase in production costs and a decrease in gold extraction (from 95% to 70-76%). Because of the short retention time of the leach circuit (18 hours) and the refractory nature of the sulphides, gold leaching kinetics are critical. A laboratory investigation was initiated to evaluate actual plant practice and identify a means of improving the gold leaching rate. The study was conducted on a "soft" sulphide gold sample containing 4.96 g/t Au, 0.4 g/t Ag, 2.5% pyrite, 1.2% arsenopyrite, and 0.2% pyrrhotite with a P80 of 74microns. Pre-leaching significantly influenced the gold leaching rate. A short pre-leach (2 hours) performed at pH 8, a DO of 8 ppm, and with 300 g/t lead nitrate added at the start or the end, produced the preferred conditions. Pre-leaching for more than 2 hours was detrimental to gold extraction. The cyanide concentration had to be maintained at 450 ppm NaCN to reach a maximum gold extraction within the retention time of the circuit. A maximum extraction of 81.3% Au was obtained in 20 hours (leach residue at 0.97 g/t Au). A high level of dissolved oxygen in the pre-leach was not of any benefit. Extension of gold leaching beyond 20 hours indicated that all leachable gold had been extracted by that time. Plant modifications were made to allow leaching of oxides and sulphides in separate circuits. Treatment of oxide ores is now performed at a higher rate. Sulphides are processed at a lower throughput, with 300 g/t lead nitrate, to allow a retention time of 22 hours. Combined throughput remains the same, and total gold recovery has increased from 76% to 80% for an additional gold production of 16,000 ounces per year.

Jan 1, 2005

By P. Oyanader

"In 2001, the Catholic University of Chile undertook a maintenance benchmarking study of six open pit copper mines having mill capacities varying between 18,000 t/d and 156,000 t/d, and collectively responsible for 58% of Chilean copper production. This paper describes the methodology used to conduct the study, as well as the overall results. Key performance indices were selected to measure the effectiveness, efficiency, and development of the maintenance process. Using a balanced scorecard philosophy, these indicators were divided into client satisfaction, financial, internal process, and learning and growth indices.Maintenance was found, on average, to be responsible for 44% of mine production costs. Percentage planned maintenance of equipment fleets was found to be low by world standards, averaging 35%, 56%, and 44%, respectively, for blasthole drill, shovel, and haul truck fleets. Fleet availabilities were found to be significantly influenced by the percentage of planned maintenance achieved, while maintenance cost per equipment was found to decrease non-linearly with increases in percentage planned maintenance. Investment in technical training (including planned maintenance practice) was found to be low by global standards. The paper concludes that fleet availability and maintenance costs in Chilean open pit operations could be considerably improved by improving and/or developing maintenance planning standards, and investing in training personnel in planned maintenance techniques"

Jan 1, 2005

By K. Horikawa, S. Kitahata, H. Kobayashi

"It has been clarified that the Al-5%Mg alloys containing 200 mass ppm of sodium showed grain boundary (GB) fracture, even when tested at room temperature, as well as at high temperatures (~500°C). SEM/EDX study revealed that the GB fracture was associated with the segregation of sodium on grain boundaries of the Al-Mg base alloys. Differential scanning calorimetry (DSC) revealed that the GB fracture at room temperature of Al-Mg alloys was caused by sodium segregation in the solid state. It was also shown that the tendency of the GB fracture strongly depended on the heat treatment; the alloys after the solution heat treatment showed severe GB fracture compared with the alloys after the homogenizing treatment. Moreover, it was shown that the GB fracture at room temperature by sodium segregation was suppressed by the addition of bismuth or indium. The suppression of the GB fracture by the additional elements was believed to be the scavenging effects by forming the sodium bearing compounds in grains.INTRODUCTIONIt is widely known that Al-Mg base alloys containing high amount of magnesium(~5 mass%)show better workability at room temperature, while that the alloys show grain boundary (GB) embrittlement at higher temperatures ranging from 200 to 500°C, depending on grain size(Otsuka, 1984), sodium impurity level(Ransley, 1959, Okada, 1997, Horikawa, 2001)and testing strain rate(Yamada, 2012). In the case of coarse-grained Al-5%Mg alloys (~300 ?m), 2 mass ppm of sodium causes severe GB fracture around 300°C, however, the Al-5%Mg-2ppm alloy does not show GB fracture at room temperature. It has also been shown that the GB embrittlement caused by 2ppm of sodium was suppressed by the additional elements, such as bismuth (Talbot, 1995), antimony (Ueda, 1997) and indium (Horikawa, 2012). Basedon these facts, we have concluded that the GB embrittlement at higher temperatures of Al-Mg alloys is attributed to the synergy effects of GB segregation of atomic sodium and GB sliding. For the GB embrittlement mechanism of Al-Mg alloys, involvement of low melting point metallic phases has been pointed out (Lynch, 2002),since the GB embrittlement appeared only at high temperatures. Up to date, the effects of high amount of sodium addition more than 2 ppm on GB fracture were not fully investigated in Al-Mg alloys. In the present study, the effect of 100 ppm ordered sodium impurity on GB fracture of Al-5%Mg alloys was examined, together with the effect of another additional elements."

Jan 1, 2017

By James Stenhouse

Abstract The aqueous oxidation of pyrite in caustic solutions under oxygen pressure was investigated by measuring that effect of reaction variable on oxygen consumption by the reactions. From the results of this investigation, a model for the process has been proposed. In this model, sulphur diffuses as a positive ion through an oxide layer which forms on the sulphide particles and is then oxidized to sulphate ion. Iron is oxidized by substitutional diffusion of oxygen atoms into the oxide layer. The effect of most reaction variables on the rate of oxygen consumption can be explained with this model. Introduction Recent investigations (1,2,3) have shown that certain sulphide ores can be readily leached by agitating the ore in the form of a pulp under pressure in the presence of oxygen. Since very little was known of the mechanism of this oxidation, a programme of investigation was inaugurated in 1949 in the laboratories of the Department of Mining and Metallurgy of the University of British Columbia. Financial support for the investigation was received from the National Research Council in the form of student grants and bursaries, from the Canadian Liquid Air Company, Limited, and from the Consolidated Mining and Smelting Company of Canada, Limited. The first objective was to devise a technique to study the primary oxidation reactions in aqueous solutions and to apply the technique to a detailed study of the oxidation of pyrite in caustic solutions.

Jan 1, 1952

By J. A. Finch

The metallurgical performance of a flotation cell is strongly influenced by the features of the bubble population, characterized by the gas dispersion properties, a collective term including bubble size, superficial gas velocity and gas holdup. It is required that gas be well distributed throughout the cell. Gas distribution is estimated here by simultaneous measurement of gas velocity (Jg) at different distances from the center (radial Jg mapping). This communication describes a technique to perform radial Jg mapping together with fundamentals for the interpretation of the data.

Jan 1, 2009

By Peter Radziszewski

"Comminition process costs, which typically represent an important contribution to mining operating costs, can themselves be divided roughly between energy and liner /charge wear. As such, developing the ability of predicting mill wear will allow a more accurate estimation of wear costs and therefore their control. In this paper and based on the possibility of estimating energy dissipated in impact and abrasion by using a discrete element charge motion model for mill charge motion simulation, media wear will be investigated principally as a function of three wear mechanisms : impact, abrasion and corrosion. Experimental results will be used to identify a total media wear model. Model results will be compared with real mill data from three operating Australian mines. These preliminary results show for the cases tested that the overall average error, as compared with the observed cases, is 0 % with a standard deviation of 66.1 %. Results from the Bond abrasion index tests, for the same cases investigated, give an overall error of 73 % and a standard deviation of 192.5 %. Further work is in progress to improve test procedure, validity and confidence.INTRODUCTIONComminition process costs, which typically represent an important contribution to mining operating costs, can themselves be divided roughly between energy and line / charge wear. In Greenfield situations where the estimation of operating costs is critical in determining project feasibility, the level of confidence in such estimates becomes quite important. With regards to media wear, the Bond abrasion test currently serves as the standard media wear prediction device. However, as shown [l, 21 test results once compared with actual wear rates can vary greatly. Figure 1 shows test results as compared with 15 cases. Average error over this data is 73 % with a standard deviation of 192.5 %. As such, developing the ability of more accurately predicting mill wear will allow greater confidence in wear cost estimation and therefore their control."

Jan 1, 2001

By Wei Sun, Jaewon Choung, Zhenghe Xu, Zhangming Cui

"High intensity conditioning has been demonstrated in a number of cases to enhance fine particle flotation. The improvement could be attributed to the enhanced formation of particle aggregates. However, the understanding of aggregation mechanisms remains rather limited. Recently, an enhanced particle aggregation was observed by the formation of small air bubbles resulting from high intensity agitations (HIA). In this study, a novel visualization system is designed and constructed for characterizing the fine bubbles formed in an HIA cell. The new design allows determination of gas evolution and bubble size distribution. With this system, the effect of dissolved air on fine bubble generation by HIA is investigated. The results show that HIA creates a favorable environment for the formation of gas nuclei and small size bubbles due to hydrodynamic cavitation.INTRODUCTIONFlotation is a dominant separation technique employed by mineral industry to recover the valuable mineral particles. However, in general, particles finer than approximately 10 µm are not effectively recovered by conventional froth flotation technique due to their low inertia and high specific surface area (Fuerstenau, 1988). Therefore, the fine particle flotation has been considered as the central challenge of flotation research. Substantial advances have been made for fine particle flotation from both a theoretical and technological point of view (Fuerstenau et al., 1979; Song and Lu, 1990; Subrahmanyam and Forssberg, 1990; Sivamohan, 1990; Sedat and Barry, 1991; Matis, 1995). High intensity agitation (HIA), for example, has found some success to improve fine particle flotation kinetics in laboratory tests (Chen et al., 1999a and 1999b; Valderrama and Rubio, 1998; Rubio and De Brum, 1994).The effect of mechanical agitation on flotation kinetics has been recognized for many years. In mid-1970s, Warren (1975) reported that increasing the shear rate of the pulp could improve the efficiency of ultra fine particle flotation. He attributed this improvement in flotation to the formation of aggregates. This concept of aggregation has been extended by Rubio (1978), and Bulatovic and Salter (1989), who employed high intensity agitation (HIA) method to promote aggregation. They found that HIA with the addition of collectors, frothers and suitable modifiers significantly improved both the flotation recovery and selectivity of ultra fine sulphide minerals. The improvement was explained by warren’s shear flocculation theory. Till now, many studies (Chen et al., 1999a and 1999b; Valderrama and Rubio, 1998) have been undertaken to improve fine particle flotation by HIA. However, most of these studies were focused on the relation between energy input and flotation efficiency. Less information was available for describing how the aggregate formed during HIA process."

Jan 1, 2006

By R. W. Wein, L C. Bliss

Northern ecosystems are dominated by a harsh physical environment which dictates a need for biological adaptation. As yet, it is unknown just how these adapted plants and animals will tolerate industrial development. Our work, sponsored by university, government and industry, is part of an effort to evaluate this developmental impact. Our present studies and the results to date will be discussed. Other problems to which the environmental student may address himself in the future to ensure against environ-mental degradation will be suggested.

Jan 1, 1971

By D. L. Mckay

"Texasgulf's 25-foot-diameter Kidd Creek No. 2 Shaft is situated next to the company's No .1 Shaft, so that both shafts can share common surface and underground facilities. Shaft construction, covering a span of five years from collaring to commissioning , started by freezing the 50 feet of grey varved clay covering the bedrock. After first completing the concrete headframe, sinking to the 5/00-foot horizon utilized two different shaft construction methods. The top 2800 feet was excavated by slashing a 6-foot-diameter borehole and hoisting the broken material up the 3OO0-foot-deep No.1 Shaft; the remaining 2300 feet was excavated by conventional benching methods. Prior to installing the 5100 tons of galvanized shaft steel on the completion of the sinking operation, the sinker was able to install all thirteen armoured electrical cables in one pass with his modified galloway stage. All loading and lip pockets were installed along with the steel guides and bun tons during the equipping operation.IntroductionOn November 21,1978, Texasgulf completed the No.2 Shaft at Kidd Creek Mine. This shaft is the largest shaft (volumewise) in North America and is unique in many respects . The purpose of this paper is to outline some of the unique features of this shaft as well as to record how this facility was constructed.Soon after sinking No.1 Shaft, Texasgulf started a program of exploratory diamond drilling from the 2800 level in No. 1 Mine. The drilling outlined sufficient ore below that level to justify a second mine. Feasibility studies demonstrated that production could be increased by one-third exclusively from this deep ore . The study called for a 25-foot-diameter shaft to the 5100-foot horizon to service a mine producing 5,000 tons of ore per working day.The site chosen for No.2 Shaft and head frame is 350 feet southwest of No.1 Shaft. This, along with No.1 Shaft, will be away from the influence of ground subsidence when mining at depth. The collar and head frame foundations are located on a flat rock ledge some 70 feet below surface. This flat ledge was found by test holing through the overburden by diamond drilling. It is fortunate that this location best satisfied the surface layout and logistics for both surface and underground ore and waste handling."

Jan 1, 1981

By A. I. A. Salama, M. W. Mikhail

"A comprehensive software package has been developed at the Western Research Centre to meet many of the coal preparation requirements in the Canadian coal industry. This package performs three main functions: (1) data handling and manipulation; (2) data analysis, including the generation of washability data, performance evaluation and prediction, density and size modelling, evaluation of density and size partition characteristics, and attrition curves; and (3) graphics output.The software described in this paper is potentially a valuable tool for coal preparation plant engineers and operators for evaluating process performance and adjusting plant density separator cutpoints. Moreover, the analytical laboratory technician could find this package very useful in manipulating and presenting laboratory results."

Jan 1, 1997

By Seong-Taek Lim

Recently, 7xxx aluminum alloys have been evolved into new variants for thick semiproducts which have low amount of 2nd phases and low quench sensitivity. Commercial 7xxx alloys, especially in the thick forgings made of big ingots, often entail microstructural inhomogeneities and concurrent poor mechanical properties due to limited heating ranges and slower quench cooling. In this study, high strength aluminum alloy 7175 and 7050 are adjusted as an attempt to control the equilibrium phases (M-, T- and S-phase) to have optimum microstructure for the thick forging applications. The effects of the relative content of (Zn, Mg, Cu) on the evolutions of the coarse equilibrium phases, hardening response and resultant mechanical properties are investigated. Equilibrium phases (M,T,S) are evolved depending on the constitutional effect, primarily the change of Zn:Mg ratio, and cooling rate following solutionizing. The formation of the T- and S-phases is effectively controlled, and M-phases are homogeneously precipitated in the adjusted (dilute and high Zn:Mg ratio) alloys. It provides extended heating range and lower quench sensitivity than conventional alloys. The attempts ensure the microstructural homogeneity and improved properties, and is expected to be uniquely applicable in 7xxx thick forgings.

Jan 1, 2004