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By W. G. McBride

THE present demand for men with engineering training exceeds anything in the history of the profession. Recent estimates indicate that mechanization of war has reached such a stage that at least twelve horsepower is required now for every one horsepower needed to run the machines of the first Great War. The scale of operations exceeds anything in the past, while more territory and people are involved than ever before. Many of our allies have inadequate or no facilities for producing the thousand and one articles absolutely necessary to the conduct of modern warfare. Lack of preparedness has made it necessary to produce at an unparalleled rate to gain parity with the enemy, while our losses have been so heavy that replacement, in itself, presents a task which might well stagger less courageous peoples. This means that not only is there an unprecedented demand for engineers to produce the machines, munitions, and supplies of war, but there is a correspondingly large need for men with engineering skill in the uniformed forces to operate and maintain the vast numbers of ships, 'planes, tanks, trucks, radios, and a myriad of other devices to carry on the varied activities of war. This abnormal demand came upon us after almost ten years of stagnation in the engineering industries. During this time many trained engineers drifted into other callings, while the lack of jobs for graduates caused a falling off in the number of men training for this profession. Consequently, the supply of well trained engineers was below normal when the madman of Germany precipitated us into the present turmoil. Added to all this, we in Canada are still suffering from governmental inefficiency in the utilization of the available supply of engineers. In the armed forces, engineers have been assigned to office and other work where their engineering training is not only wasted but for which men with more suitable training could be found. Mining engineers are debarred from service as aeronautical engineers, and students in mining engineering are denied the bursaries provided for aiding students in engineering. Mining and metallurgical engineers are both barred from the Ordnance department of the army. This arises from a misunderstanding in relation to engineering training. In Canadian engineering schools, all engineers are given a sound training in the branches of human knowledge which are fundamental to engineering: mathematics, physics, and chemistry. The basic difference between the several categories of engineers lies in the fact that training in the application of this fundamental knowledge to the solution of engineering problems is given in different subjects.

Jan 1, 1942

By F. D. Ford, Z. Dai

"Vale’s Ontario Operations re-introduced Cu/Ni separation at Clarabelle Mill in 2006. The mill processes ores from a number of mines in the Sudbury basin. A saleable Cu concentrate is produced at 30-60% Cu recovery from mill feed, which has to meet the quality specification. In particular, Ni content in Cu concentrate must be less than 0.6%, otherwise, penalties will apply and diminish the value of Cu concentrate, in addition to the lost Ni value. Generally, a Ni grade of less than 0.4% is obtained in Cu concentrate. More recently, while processing Cu-rich ore, Cu concentrate contained more than 0.6% Ni which is abnormally high. Detailed mineralogical investigation shows that Cu-rich ore contains more millerite in comparison to typical Sudbury Ni sulphide ore. Millerite is found to be more floatable than pentlandite and is much more difficult to depress using high-lime aeration conditioning, which is the standard practice in Cu/Ni separation to float chalcopyrite while depressing pentlandite. The current operation uses sodium cyanide at 20 g/t to depress pentlandite and pyrrhotite. However, it is found that a high dosage is required to depress millerite. It is also shown that starch and dextrin are promising in millerite depression.INTRODUCTIONPrior to bulk smelting in 1991, Cu/Ni separation was carried out at Vale’s Copper Cliff Mill, Ontario Operation. The typical Cu concentrate grade was around 30% Cu and 1% Ni. This is very high in comparison to today’s value of 0.4% Ni and would not be acceptable for external processing. However, the Cu concentrate was processed internally at the Copper Cliff smelter/refinery, so the Ni contained in Cu concentrate was not lost and no actual penalties applied. During the SO2 abatement initiative, bulk smelting was chosen because of the perceived simplicity and consequently, Cu/Ni separation was eliminated (Agar, 1991) and the Copper Cliff mill was subsequently demolished. In 2005 and after more than one decade of bulk smelting, business changes required the removal of some Cu concentrate from Clarabelle Mill bulk concentrate to provide smelter capacity for Voisey’s Bay concentrate in the Copper Cliff smelter. In essence, this strategy calls for Cu removal at Clarabelle Mill (Lawson, 2006). In this case, Cu concentrate is sold externally and it must meet the quality requirement of less than 0.6% Ni."

Jan 1, 2011

By P. Woo, N. Brodusch, R. Gauvin, H. Demers

The scanning electron microscope (SEM) was primary developed for imaging applications. With the introduction of the Si(Li) energy dispersive spectrometer (EDS), simultaneous imaging and x-ray microanalysis became possible. However, long working distance and high current were needed because the position and small solid angle of the EDS detector. The high spatial resolution is generally obtained at short working distance with a SEM. Unfortunately x-ray microanalysis is never performed in the best imaging conditions. The annular silicon drift detector system is inserted below the objective lens which gives a higher solid angle (up to 1.3 sr). In consequence, a lower working distance and probe current can be used. An improved spatial resolution becomes possible during x-ray microanalysis. With this x-ray detector installed on a cold-field emission scanning electron microscope, quantitative x-ray microanalysis with high spatial resolution at low beam energy and low current becomes possible with the possibility of using the various different type of imaging at the same time. Also, since the count rate can be as high as 1,500 kcps, which lowers significantly the detection limit of elements as well as the minimum feature sizes of different phases that can be distinguished.

Jan 1, 2014

By Shae K. Kim

The aim of this study is to manufacture magnesium alloys with alkaline earth metal oxides (BeO, CaO, MgO or SrO) additions with the objectives of (1) ensuring safety during processing and applications by raising the ignition temperature and reducing oxidation, (2) protecting the environment by reducing or eliminating use of protective gases, (3) maintaining or improving elevated temperature properties with lower amount of Ca or Sr or rare earth metals when compared with conventionally developed high-temperature magnesium alloys, (4) developing cleaner strip casting and continuous casting processes without hot tearing and (5) obtaining all of these objectives without sacrificing mechanical properties or increasing the cost of magnesium alloys.

Jan 1, 2006

By Lewis Martin

Whereas many researchers and mine engineers have conducted tests using different types of grout, grout ratios, and physical modifications of the cable to determine cable bolt load characteristics, few studies have been conducted on cables fitted with internal instruments. Those studies that have been done have concentrated on cable behavior averaged over significant cable lengths. Researchers at the Spokane Research Laboratory (SRL) of the National Institute for Occupational Safety and Health in Spokane, WA, are investigating the physical properties of cable bolts by replacing the conventional king wire with a modified king wire on which strain gauges have been installed . This paper documents test results on these modified cable bolts. Three tests were conducted at SRL on 1.83-m-long cables grouted into two 0.91-m-long pull-tube assemblies. Load along the cable was monitored with 20 strain gauges installed along the length of the cable. The instrumented cable bolt provided reproducible point measurements of cable load as opposed to load measurements averaged over significant cable lengths. Such point measurements can assist in interpreting the influence of cable confinement, grout quality, rock mass stiffness, and other factors. The instrumented cable bolt is a practical field and research tool because it can predict point loading along the cable and thereby allow interpolation of maximum possible loads on a cable.

May 1, 2002

By J. Muralha, L. Lamas

"Given the results of triaixial tests, regressions are commonly used to evaluate the parameters of failure criteria that model intact rock strength and to perform statistical inferences used to evaluate characteristic values defined in EC7. Statistical robustness of these inferences is affected if the basic hypothesis underlying regression are not met, namely homoscedasticity (constant variance of the errors). This paper presents analyses of 23 sets of triaxial tests, starting by the evaluation of the regression parameters of the Mohr-Coulomb linear criterion and of the Hoek-Brown non-linear criterion, followed by carrying several statistical tests to check the homoscedasticity null hypothesis of independence between the variance of intact rock strength and the confining stress.INTRODUCTIONThough rock engineering design is clearly included in the scope of Eurocode 7(EN1997-1), its implementation raised a wide discussion regarding the applicability of structural safety concepts to geotechnical design of construction works in or on rock masses. The basis of the limit state design philosophy adopted in EC7 is that, for each particular design situation, all the possible limit states for a structure, or part of it, shall be considered and that it shall be demonstrated that the likelihood of any limit state being exceeded is sufficiently small. Though EC7 allows the limit states to be verified by one or a combination of methods, use of calculations is by far the most used, and it is often confused with the EC7 itself. It involves using characteristic values of actions, ground properties and geometrical data, as well as obtaining their design values by the partial factor method.Characteristic value of a given material property is defined in Eurocode (EN 1990) as: “value of a material or product property having a prescribed probability of not being attained in a hypothetical unlimited test series. This value generally corresponds to a specified fractile of the assumed statistical distribution of the particular property of the material or product”. As regards the design value of a material or product property, according to the Eurocode it is a “value obtained by dividing the characteristic value by a partial factor”."

Jan 1, 2015

By M. Leroux, P. Lacombe, S. R. Rao, J. Y. Kim, J. A. Finch, G. Labonté, N. Macminn, M. Ounpuu

"Laboratory investigations on two complex ores, the A1 zone ore from Les Mines Selbaie and the Lyon Lake ore from Mattabi Mines Ltd. (Division of Noranda Minerals), have been carried out to determine some of the main variables in collectorless flotation. In particular, the effect of pulp potential (controlled by gas composition), conditioning time, pH and grinding media have been studied.Chalcopyrite showed the greatest response to collectorless flotation among the four major sulphide minerals present, followed by galena. Flotation of sphalerite was variable from minimal to important depending on the mineralogy and the pre-treatment performed. Appreciable silver recovery was achieved collectorlessly for the Lyon Lake ore while it could not be achieved for the A1 zone ore of Les Mines Selbaie. It appears that the difference between the two ores is related to silver's predominance as tetrahydrite in the Lyon Lake ore while it is as argentite and native silver in the A1 zone ore.The response of the ores to collectorless flotation is strongly dependent on the pulp potential, Ep, and pH. Using different gas compositions and different conditioning times it was found that collectorless flotation occurs when Ep is +195 to +295 mv (vs SHE). The actual on-set potential for collectorless flotation is dependent on the ore. A too high potential or prolonged oxidation leads to a decrease in selectivity. Some other factors were examined, notably the effect of pH and the type of grinding media on the selectivity achieved in the laboratory.Preliminary results from a plant trial at Mattabi Mines Ltd. confirmed that collectorless flotation occurs and that it is preferential for chalcopyrite and to a lesser extent galena. Collectorless flotation was not attempted at Les Mines Selbaie. However, examination of the distribution of collector between the different addition points in the copper circuit suggests that it may be present."

Jan 1, 1990

By A. G. Doll

"Many power-based grinding models exist, and most operators are familiar with Fred Bond's ""third theory"". Bond's model is most commonly used to describe primary and secondary grinding to product sizes above, for example, 100 µm. Operators sometimes use Bond's equation to describe grinding in situations where it is not appropriate, such as fine grinding below 50 µm. Using an alternative model would be a better choice in this situation.Bond's equation is one in a large family of models. Related equations better suited to fine grinding include the “signature plot”, Von Rittinger's model and Charles' equation. These models have a similar form to Bond's and can be fit to industrial regrind mills and laboratory tests using the simple regression tools in the charts of computer spreadsheets. Operators will find that fine grinding calculations are both easier and more accurate when using the alternative equations to fit their regrind milling surveys or when performing laboratory regrind mill scale-up for plant design.None of these models are new: Charles' equation was published in 1957 and Von Rittinger's model was proposed in 1867. A quick refresh how to apply these equations can turn these oddities from the undergraduate curriculum into useful tools for plant optimization. They can be fit to any type of mill including stirred and tumbling ball mills.IntroductionBuilding a case for fine grind modelling requires reviewing some theory before building a framework for doing fine grinding calculations. The actual calculation procedure recommended is easy and can be applied by plant metallurgists. Don’t be frightened by the theory; the end result is reasonably simple.The observation that mineral breakage is related to the absorption of energy is usually attributed to Von Rittinger (1867). Lynch and Rowland (2005) describe that the ability to empirical test and calibrate energy models of breakage didn’t exist until the widespread adoption of electric motors in the mining industry during the 1930’s and 1949’s. A series of technical papers published by the Allis Chalmers company during the 1940’s demonstrate that they were attempting to do such a calibration using Von Rittinger’s model which is usually stated as: “the energy consumed in the size reduction is proportional to the area of new surface produced.”"

Jan 1, 2017

By M. O. Makwarela, M. W. Erwee, K. Bisaka

"Energy efficiency in mining and minerals processing forms part of Mintek’s long-term research strategy which includes a specific programme designed at overcoming the challenges faced by the South African pyrometallurgy industry.The electric smelting industry is currently severely constrained by the global economic downturn as well as by the availability and increasing cost of electricity. Efficient utilisation of electricity through energy recovery systems and improved smelting process flowsheets can significantly contribute towards creating sustainable operations.Apart from efficient engineering design and solid process control, smelting of either cold or hot pre-reduced ores has been shown to decrease furnace electricity consumption by more than 40%. Various methods of solid-state reduction tests have been carried out at Mintek in order to select the most appropriate process option in the context of the South African industry. This paper summarises a subset of the results obtained, specifically on pre-reduction tests done on South African chromite and manganese ore pellets.In this set of tests, it was found that the use of an organic binder, together with B2O3 as flux, promotes manganese ore pre-reduction, but retards the pre-reduction of chromite. By pre-reducing the manganese ore feed, significant cost savings can be achieved in subsequent smelting processes and there is potential to minimise manganese losses as a result of fuming, due to possible lower operating temperatures."

Jan 1, 2016

By Euler De Souza

Backfilling in Canadian mines has been practised for close to 100 years and evidence anticipates the application of mine fill technology at an increasing rate during the foreseeable future. The evolution of backfill technology is closely related to the advancement of modern mining methods and the development of new backfill technology continues to evolve. The authors, after conducting extensive surveys of backfill practices in underground mines across Canada, have concluded that, because backfill operations employ large quantities of cement and experience large costs associated both with backfilling practice and cement use, opportunities exist for reducing backfill energy costs and enhancing the application of alternative cementing agents in backfill. Consequently, the authors have developed an alternate, equally effective and lower cost binder agent replacement for cement, and incorporated waste glass into the development of a lower cost backfill (glassfill). This paper presents the results of two design stages associated with the development of glassfill: strength development and flow performance. The advancement of this technology has reached a stage that should promote industrial implementation within the Canadian mining industry. A number of Canadian mining operations exhibit potential for plant optimization through possible binder source replacement, and might thus realize associated reductions in backfill and energy costs.

Apr 1, 2005

By D. W. Davis, P. Landais, L. J. Robb

Nodules of carbonaceous matter have been observed in several Archaean peraluminous granites adjoining the gold- and uranium-bearing Witwatersrand Basin. These nodules, which resemble solid bitumen, usually replace uraninite or uranothorite and are paragenetically late. They show many similarities to kerogen seams and nodules associated with the conglomerate horizons in the Witwatersrand Basin, including composition, maturation, intimate association with uraninite, and a late paragenesis. U-Pb isotope ratios for granite-hosted and Witwatersrand kerogens define a single, albeit somewhat diffuse, Ph-loss discordia suggesting an upper intercept age of circa 2300 Ma. Carbon isotope analysis indicates lighter Ol3C values for the granite-hosted nodules than for the sediment-hosted kerogen seams. Raman spectroscopy indicates that granite-hosted kerogen is more highly ordered than Witwatersrand seam kerogen. A model is presented which links the granitoidand sediment-hosted organic matter to an event of oil generation in the Witwatersrand Basin circa 2300 Ma ago. Light hydrocarbons migrated through the sediments and into underlying/adjacent granitic rocks, undergoing polymerization and accumulation in response to radiation accompanying the presence of high-uranium phases.

Jan 1, 1994

By J. Châteauneuf, R. Dupéré, D. Mrabet

"In gold processing plants, it is common to start gold cyanidation in the grinding circuit by simple cyanide addition or as a result of recycling residual cyanide. In such cases, advantages such as a decrease in gold lockup and reduced leach time have been noticed. The prevailing conditions in grinding circuits such as intense mixing, particle breakage and friction or high temperature are quite different from those found in tanks and so is the resulting cyanidation behaviour. To gain a better understanding of the cyanidation behaviour in mills and of the pertinence of cyanide addition in grinding circuits, lab tests were conducted using an industrial ore from Canadian Malartic mine. In this study, the effects of different parameters on cyanidation in grinding circuits were examined; parameters such as such as temperature, dissolved oxygen, cyanide concentration and pH. The results showed that the kinetic benefits of high temperature in the mill can overcome the low dissolved oxygen concentration thus leading to an overall gold dissolution kinetics improvement for temperatures up to 50°C. However, gold leach in the studied grinding circuit at lab scale caused an increase in cyanide consumption with a higher generation of iron cyanide and SCN-. These results were confirmed by tests in the Canadian Malartic plant where the cyanide addition was moved from the SAG mill to the leaching tanks resulting in a 20% savings in cyanide consumption.IntroductionCyanidation in grinding circuits can benefit gold processing by decreasing gold lockup and by reducing leach time. However, other aspects regarding gold and cyanicide dissolution come into play in the conditions prevailing in grinding circuits. Indeed, high turbulence, high temperature, recycling load, friction and particle breakage make cyanidation behaviour in grinding circuits different from in-tank cyanidation (Marsden and House, 2006). In several cases, cyanide in grinding is limited to a very low level or completely avoided such as in circuits with gravimetric separation, for ores requiring oxidative pretreatment or for preg-robbing ores. In other cases, water management imposes a certain recycling of residual cyanide. This problem is generally addressed by a case-by-case approach. However, the chemistry of cyanidation in mill circuits is worth investigating in order to assess the advantages and disadvantages."

Jan 1, 2016

By Philip M. J. Gray

"The real cost of conversion from ore to semi-fabricated non-ferrous metals has been increasing for many years. Consumer resistance and improved knowledge and techniques now available justify investment in revolutionary as well as evolutionary methods of extraction. Metallurgical factors in current practice which preordain high production costs are identified as: smelters' demand for clean minerals, use of processes with low intensity of working per unit of reactor volume, use of low-velocity reactions, use of long reactor retention times relative to the speed of reactions, dilution of values in solution and commitment to electric power as a source of energy.Six new types of flowsheet are proposed for processing from ore to metal, composed of steps which are economic to construct and maintain and making maximum direct use of fossil fuel and the energy content of minerals. The basic knowledge and technology for developing these flowsheets exists. It is very tentatively suggested that these routes might reduce the capital and production cost for conversion of ore to metal by 30-50%."

Jan 1, 1980

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 H. Hitchen

THE object of this paper is to present the various facts that l1ave been revealed during lengthy investigations into the performance of all types of ropes on different hoisting installations. It then goes on to suggest means by which most of these findings could be usefully employed to obtain more economical rope lives with increased safety. SHAFT HOISTING ROPES Four basic designs of ropes are now employed for hoisting duties: (1) Six-strand, round strand ropes with fibre cores. (2) Six-strand, triangular strand ropes with fibre cores. (3) Non-rotating, multi-strand ropes. 0) Locked coil ropes. Round Strand Ropes (Figure 1) Very solid and reliable ropes can be obtained with this simple geo-metric design of strand. 1'1?iangula1? Strand Ropes (Figure 2) Owing to the fact that the wires in the strands are bent over a triangle, they do not seat quite so solidly as when they are bent over a circular core wire, as is the case with

Jan 1, 1963

By Xu Wang, Yizhe Zhang, Yangge Zhu, Xiao’ou Xia, Fangming Liu

"The progress of lean magnetite preconcentration in China was introduced in this paper, such as using coarse crushing to reject tailings, and multistage grinding, multistage magnetic separation. The applications of “more crushing and less grinding” process and equipment in lean magnetite preconcentration could reduce production costs effectively. The related analysis and study on concrete cases were carried out in this paper.INTRODUCTIONIn the case of the slowdown and weak recovery in the global economy, bulk commodity prices fell sharply in 2015. Take iron ore's prices for example, about 60% grade iron ore's import prices in China from about $65 per ton at the beginning of 2015 fell to about $42 per ton in the end of the year, down by about 35%. But iron ore resources are non-renewable resources, with the continuous development and utilization of mineral resources, high grade iron ore resources will be exhausted gradually. Accompanying with the economic recovery iron ore prices after this fall is bound to return to its value to maintain a high level.The development and utilization of resources is gradually turning to the low grade iron ore. Restricted by technical development level and disadvantages of lean iron ore resources, the cost of utilization lean iron ore resources is relatively high. Making full use of their rich lean ore resources has become many countries' important strategy to get rid of dependence on foreign countries' ore. Over the years with the development and progress of lean magnetite mineral processing technology in China, the production number of concentrator has been greatly improved.As the world's largest steel producer and consumer countries, ensuring a stable and continuous supply of iron ore is particularly important for the healthy development of China's iron and steel industry. Chinese iron ore production and import data in recent years are showed in Table 1.With the expansion of iron and steel production, iron ore demand has also been a phenomenal growth. Taking 2013 for example, China's crude steel production is about 780 million tons in 2013, accounting for about half of the world's total output of crude steel. At the same time, China is also the first major iron ore import countries whose iron ore imports in 2013 was about 820 million tons, an increase of about 10%. The degree of external dependence is very high. In some years, the cost of China's iron ore imports was even more than $100 billion, and second only to oil’s import cost in all bulk commodities."

Jan 1, 2016

By Robert A. Brown

"The O'Brien mine is in the west-central part of Cadillac township along the Cadillac 'break', which extends for 7,500 feet from west to east across the property.The ground was staked in 1924 by A. Dumont and W. Hermeston, prospecting for M. J. O'Brien, Limited. The first vein discovered is that now known as No. 1. The No. 4 vein was later exposed on the surface; the other veins known to be present were revealed by underground work and diamond drilling carried out both from the surface and underground.The mine is developed from three vertical shafts: No .. 2 extending from the surface to 2,000 feet; No. 3 from the surface to 1,500 feet; and No. 4 from 2,000 to 3,000 feet. There is on the property a mill of about 200 tons a day capacity, the usual shops, and a townsite housing about forty-five families. Gold production to the end of September, 1944, amounted to 295,824 fine oz. from ore having an average grade of 0.505 oz. a ton. In addition, the mill recovered 3,237 tons of arsenic trioxide having a purity of 83 per cent As2O3.GENERAL GEOLOGYThe four main groups of rocks of the Cadillac area- the Cadillac, Blake River, Kewagama or Pontiac, and Malartic- are found within the boundaries of the property. However, as these rocks have been fully described in · various government reports (1,2,3,4,5,6) and all the known orebodies occur within one group- the Blake River-a detailed description of the geology will be dispensed with here. The known ore deposits lie south of the Cadillac 'break' in a group of rocks that includes 'greenstones', greywackes, conglomerate, porphyries, and a rock of gabbroic composition that may be intrusive. Both flows and tuffs can be recognized in the 'greenstones'. The two bands of porphyry that trend easterly across most of the property have been considered by some observers to be dyke rocks and by others to be flows. Certain evidence points to their being dykes that were intruded as sills considerably prior to the emplacement of the gold-bearing veins, but the possibility of flow origin cannot be fully rejected. North of the talc-chlorite-carbonate schist zone forming the 'break' the rocks are conglomerate and greywacke with iron formation, in which there are no known veins of ore grade. Within the schist zone are minor acid and basic intrusives. The general trend of both bedding and schistosity is a few degrees south of east. The dip is generally vertica1 or steep to the south."

Jan 1, 1954

By L. Tong

The nickel laterite ore is composed of soft and hard minerals, and nickel distributes preferentially into the soft mineral rather than in the hard. Selective comminution of saprolitic and goethitic nickel laterites is investigated to upgrade nickel into the fine fraction using stirred milling. The optimal selective grinding conditions were determined through a kinetic study and the limit of selective grinding and nickel upgrade was analyzed. The breakage rates of minerals, grinding time, and the weight ratio of soft and hard minerals in the feed play an important role in selective grinding. A small breakage rate on hard minerals and a large breakage rate difference between the minerals are optimum for selective grinding. The soft mineral grade decreases with grinding time and the optimum grinding time is a trade-off of the soft mineral upgrade and recovery. The minerals weight ratio determines the limit of selective grinding. The effect of nickel upgrade is determined by both the conditions that influence selective comminution and the nickel grades in both the soft and hard minerals. The nickel grade in the soft mineral determines the limit of nickel upgrade.

Jan 1, 2015

By Y. Long

The deep-hole surface blasting technique is a prime method of iron ore mining. Blasting fragmentation is one of the important economic indicators that measures the blast method to obtain the iron ore. To improve the efficiency of the blasting method and further reduce the cost of the subsequent processing of iron ore, this paper summarizes measured data gained from a certain amount of blasting test conducted in an iron ore mine in Guangdong province, China. According to the data analysis, there are differences on iron ore blasting fragmentation by different indicators of deep-hole blasting, such as decoupling coefficient of charge, contact state between charge and borehole wall, and change of detonation position in charge. These factors were compared in terms of relevance and impact. Research shows: under certain rock conditions, the decoupling coefficient of the charge has a best range related to blasting fragmentation. Since the detonation position in charge determines the direction of propagation of the explosion stress wave through ore and rock, bottom initiation and mid initiation will help to improve the iron ore blasting fragmentation in joints fractured rock and ore. The research conclusions have important application value for program design of iron ore surface blasting and to guide other types of rock surface blasting.

Aug 1, 2013

By H. R. Wilson

"This paper describes the evolution of the Waste Management Program at the Lupin Mine through the years 1982 - 1988. The program was developed in response to the terms and conditions of the Water Licence issued to the mine in 1981 by the Northwest Territories Water Board. Echo Bay Mines Lupin Mine is located on the western shore of Contwoyto Lake in Canada's Northwest Territories about 80 km. south of the Arctic Circle.The gold mine commenced production in 1982 and the Waste Management Program was based originally on the total containment concept. Due to an expansion of the mill circuitry and increased throughput, it was apparent that the total containment concept would require reevaluation since discharge from the pond would be required within a few years. During the initial years of production, an investigative program was established to determine the most effective means for treating the tailings pond water. This program incorporated both laboratory studies as well as monitoring of the tailings pond contents and environmental conditions as the impoundment area was filling. The program showed that natural degradation phenomena, if properly utilized, are effective in lowering the concentrations of all contaminants to within Licence limits with the exception of arsenic. To ensure compliance with arsenic limits, an iron salt was added to cause arsenic to precipitate from solution in the tailings pond.As a result of our studies, the tailings management system finally implemented at Lupin Mine includes the following components:Tailings pulp retention cells constructed by dyking off one end of the tailings impoundment area.Two tailings ponds in series operated in a sequential decant and fill fashion.An iron salt solution preparation and metering system.A syphon system into which the iron salt solution is injected as the contents of the first pond are decanted into the second pond.A second syphon system for decanting the contents of the second pond to the receiving streamThis paper discusses the findings and conclusions of the waste management investigative program, describes the civil work completed to reach our final operating scenario, describes the sequence of operating the treatment system, reviews performance data, and comments on abandonment and restoration of the tailings impoundment area."

Jan 1, 1989