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By J. P. Grau, J. Z. Lu

"Thickeners/clarifiers are widely used in coal preparation plants, potash processing and other mineral processing facilities. Thickeners play a very important role in slurry treatment systems to accomplish solid/liquid separation. The demand for larger plants and the increased thickener handling capacities sometime require thickener diameters as large as 200m. The development and use of high capacity thickeners makes it possible to increase the handling capacity of these thickeners by several to more than 10 times compared to conventional thickeners. Hence, for a given slurry rate, selection of a high capacity thickener will significantly reduce the footprint of the thickener. Much higher handling rate, higher concentration of underflow, clearer overflow and lower capital cost are obvious advantages of high capacity thickeners; however, some process requirements and the concerns of operational cost, especially the flocculant cost of a high capacity thickener operation, keep some engineers selecting conventional thickeners and staying away from the high capacity thickeners. Forty years after the first high capacity thickener was developed, there are still arguments in the selection of conventional thickeners or high capacity thickeners in mineral processing. The arguments will continue unless there is a clear picture of capital cost vs. operational cost for each of the thickener types. The purpose of this paper is to analyze these costs and to provide guidelines for selection of thickeners. INTRODUCTIONThickeners/clarifiers are widely used in various slurry treatment systems. For mining and mineral processing, thickeners are an integral part of the solid/liquid separation system. The feed to the thickeners are processing slurries. The fundamental mechanism for the solids/liquid separation is for the solid particles in the slurry to gravity settle inside the thickener tank. The clear water overflows from the top of the thickener tank and is typically reused in the processing circuit, and the concentrated underflow is discharged to different downstream process systems depending on the application of the thickeners. The general requirements for a thickener operation include high density of underflow and clear overflow. Since thickener operation consists of continuous feeding, overflow and discharge of underflow, the solid particles will gravity settle against an upward flow with its velocity dependent on the feed rate and the underflow discharge rate. Higher feed rates to a given thickener produce higher upward velocities. Underflow discharge is typically relatively small compared to the amount of overflow. The upward flow tends to take particles up to the overflow. Only those particles having a settling velocity greater than the upward flow velocity will possibly settle out. Hence, thickener feed rate has to be controlled so that the required overflow water clarity can be achieved."

Jan 1, 2012

By J. C. White

"This paper was prepared for and presented at a lecture series on ""Materials Randling"" at McGill University. The development of trackless mining at Gaspe Copper Mines, Limited is described, showing the changes in mining method and the part played by the mobile equipment in the evolution of this highly mechanized underground operation. Comparisons of loading and hauling machines are given and an attempt is made to predict some possible future developments.INTRODUCTIONTHE PROPERTY OF GASPE COPPER MINES LIMITED is located in the Gaspe Peninsula of the Province of Quebec, 60 miles west of the village of Gaspe and 25 miles south of the St. Lawrence River. The original discovery of low-grade ore was made at Copper Mountain in 1921. Subsequent exploration revealed the richer Needle Mountain orebodies, and eventually in 1951 the decision was made by Noranda Mines to build the mining, concentrating and smelting complex (Figure 1). Construction and development of the mine was commenced in 1952 and production started in 1955."

Jan 1, 1968

Aur Resources is Canada's leading copper mining company with producing mines and development projects in North, Central and South America. Copper production from Louvicourt Mine in Quebec, Quebrada Blanca and Andacollo Mines in Chile was a record 245 million pounds in 2001. Located 600 km North of Montreal, Louvicourt Mine is a joint venture between Aur Resources (30%), Novicourt Inc (45%) and Teck-Cominco (25%). Aur Resources is the mine operator with 280 employees working to produce a copper and zinc concentrate. In operation since 1994, the mine has produced a total of 12,606,000 metric tonnes of ore grading 3.6% Cu, 1.5% Zn, 26 gr./m.t. Ag and 0.9 gr./m.t. Au. This highly mechanized mine reached full production in August 1995 at 4,000 tpd. From 1996 to 2001, the average mine production rate was more than 4,300 tpd. The Louvicourt Mine continued its record of solid performance in 2002 and is expected to continue to do so for the balance of its 2.5 years mine life.

May 1, 2003

By Alfred C. Lane

Reference to the original use of the terms Laurentian and Huronian (and its extension), shows that the former was applied to granitized sedimentary and metamorphic pre-Cambrian rocks, and the gneissoid igneous rocks associated therewith, and the latter to non-fossiliferous rocks supposed to be later. But it appears from the work of Collins, Quirke and others that there is more or less of an overlap, and that of the original Laurentian the Grenville limestone, and some of the granites, may be later than the lowest part of the original Huronian. Before we can decide whether to abandon one or the other of the two terms, or how to delimit them, it is important to know the extent of this overlap. The Pb :U ratio, though not to be depended upon too minutely, does give a real idea of the age of a mineral as it increases with the decay of uranium, and so is greater the longer the time since the uranium was separated: and there are reasonable prospects of help there from in getting a knowledge of the relative age of different granites to assist in solving the problem, as facts already collected show. 1. Historical review of the use of the words Laurentian and Huronian: 2. Difficulty encountered: 3. Popular account of atomic disintegration: 4. Methods of estimating age by it: 5. Applications.

Jan 1, 1925

By K. Izumi

Ultra-grain refinement and high strengthening of metals by accumulative roll bonding (ARB) was widely reported. However, applications of ARB to magnesium alloys were rather limited. In this study, Mg-9%Li-1%Y sheets were applied to ARB at room temperature. Six 0.5 mm thick sheets were stacked and reduced into 0.5 mm thick by four passes. The procedure was repeated up to three cycles, so that the equivalent strain of 6.2 was applied. The sheets show dual phase structure with a (hcp) and ß (bcc). Grains elongates to the rolling direction with increasing number of ARB cycles. After three cycles, fragmented a grains with average size of about 300 nm are uniformly distributed. After the first cycle, the ultimate tensile strength increases to 180 MPa from 133 MPa, while the elongation decreases, however, still high (26%). The tensile strength slightly decreases by the second cycle and does not change at the third cycle. Meanwhile the elongation increases by the second cycle and the sheets show 41% of the elongation after the third cycle.

Jan 1, 2006

By Arthur Notman

Since addressing the Institute a year ago on The Future of the Copper Industry (l), many things have happened, most of them bad. It has been a hard year for profits and prophets. It was, therefore, with consider-able perturbation that I accepted the gracious invitation of your Committee to reappear. On reviewing my remarks of a year ago, I. have wondered whether, under pressure of more important matters, the Committee had neglected to make a note of them, or whether they felt that further explanations from me were in order. In either event, I am glad that I am here and welcome the opportunity to make any contribution I can to a clearer understanding of the problems of copper to those concerned. The English-speaking nations own 80 per cent of the present world-production of the metal. Col. P. E. Barbour, Secretary of the Mining and Metallurgical Society of America, and I recently completed an estimate of the known world resources of copper. We placed the figure, in round numbers, at 100,000,000 tons of metal. Of this amount, about one-third lies in the United States, one-third in the British Empire, and one-third in South America; and all but 4 per cent of this is owned by British Empire and United States capital. Our figures do not include any estimates for Russia, Japan, or Europe, on which there are no available data. It is true, consequently, that the British Empire and the United States are the ones concerned. It seems to me to be a matter of great importance to the world at large, and of even greater importance to those nations themselves, that the known sources of supply of this metal, so essential both in peace and war, rest so strongly in their hands. I cannot believe that in the long run they will neglect their responsibilities in the wise administration of these resources.

Jan 1, 1932

By R. Drozd

"The Bui/moose Mine is in the northeast coal area of British Columbia, and less than $300 million was spent to bring this 2.3 million-tonnes-per-year metallurgical and thermal coal mine into production by November 1, 1983, one month ahead of schedule. The project is an unincorporated joint venture undertaking, with Teck-Bullmoose Coal Inc., a wholly-owned subsidiary of Teck Corporation, holding 51%, Lornex Mining Corporation holding 39%, and Nissho-lwai (Canada) Ltd. holding 10%. Bullmoose Operating Corporation will be the manager and operator of the project. This paper will broadly cover the history and exploration work on the property, the geology, open-pit mining plans and equipment, the preparation plant flowsheet from breaker station to clean coal silo, the 35 km highway truck haul, the railroad loadout system, manpower requirements, approvals and permits, and general financial arrangements. Introduction The Bullmoose Mine Project is located about 87 km by road south of Chetwynd, B.C. and consists of an open-pit coal mine, a plant facility in the Bullmoose Creek valley below the mine, and a separate rail loadout facility on the British Columbia Railway Branchline near the new town of Tumbler Ridge some 35 km by road to the east. The plant will be capable of producing a total of 2.3 million tonnes per year (mty) of washed metallurgical and thermal coal. Long-term metallurgical coal contracts for high-quality, medium-volatile, bituminous coal have been signed with nine Japanese buyers for 1.7 mty, and the balance of0.6 mty will be for thermal coal production. Plant construction began in the spring of 1982, and in May 1983, preproduction waste and overburden removal in the mine was started. The plant began tuning up in October and was fully operational by December 1983. Metallurgical coal began moving to the coast in unit trains during November, and first vessel loading at the Ridley Island port began in late December 1983."

Jan 1, 1985

By Derek V. Ellis, Jack L. Littlepage

"Marine ecosystem effects ar1smg from the discharge of man-generated wastes to the sea can be schematized as: acute poisoning, chronic poisoning, enrichment, suffocation, temperature effects, salinity effects, toxin bio-concentration, changed production rates and changed species equilibria. A professionally designed site-specific monitoring program to check for such effects can not only safeguard the marine ecosystem from degradation, but it can also protect the industry involved from unanticipated remedial action after expensive construction has been undertaken. Monitoring programs should consist of three steps. Step 1 is an ecosystem survey which should be undertaken prior to final design of the discharge system and submission of applications for permission to discharge, because there can be considerable cost savings in obtaining information at an early stage in development. Step 2 involves location of the effluent field at the time of starting discharge, and analysing its dispersal behaviour. Step 3 consists of ecosystem monitoring with sampling stations and specific tests based on the accumulated prior information."

Jan 1, 1972

By R. H. Chambers, L. Alderman

"The paper is introduced by an examination of the factors which have led to the present world-wide interest in charging preheated coal to coke ovens. Various possible methods of preheating and charging the coal are considered and reasons are given for the adoption of the methods chosen. The design of the pilot preheating plant for the British Coke Research Association is discussed and its influence on the design of the commercial units for the South African Iron and Steel Corporation's plant at Pretoria and the British Steel Corporation's plant at Beighton are explained. Operating procedures on the pilot plant are described, particularly with regard to the charging of the preheated coal. Design features of the commercial installations, engineered by Simon-Carves Ltd., are explained with emphasis on the built-in safety of the control system of the preheating plant, and the particular problems associated with the erection of such plants on working coke oven batteries. Commissioning and operating procedures are described and the problems associated with the integration of the preheating plant into the normal pushing schedule of the plant are discussed. Preliminary operating results with regard to the effect of preheating on coal throughput on the commercial plants and on the properties of the coke produced are given."

Jan 1, 1972

By R. F. Coulter

THE Flin Flon concentrating and metallurgical plants (Figure 1) of the Hudson Bay Mining and Smelting Co., Limited, lie adjacent to the town of Flin Flon, on the Manitoba-Saskatchewan border, 400 miles northwest of Winnipeg. Since the start of milling operations in 1930, over 50 million tons of ore from the Flin Flon mine have been treated in the concentrator. During the past few years, newly discovered orebodies have been brought into production and their ores processed at the company's main metallurgical plants. All these properties are within a 75-mile radius of Flin Flon and have aided substantially in augmenting plant metal production as well as retarding depletion of ore reserves in the Flin Flon mine. •Current satellite producers are the Schist Lake, Coronation, and Chisel Lake mines. The Schist Lake mine, located 3 ½ miles southeast of the main plant, is a copper-zinc producer. It was brought into production in 1954. The

Jan 1, 1962

By Clifford S. Gibson

THE Workmen's Compensation Ace defines Silicosis as "a fibrocic condition of the lungs caused by the inhalation of silica dust sufficient co produce a lessened capacity for work". This fibrocic condition muse exhibit a specific appearance in the X-ray picture of the chest-an appearance which is not characteristic of several lung conditions which can cause lessened capacity for work and which are not due co silicosis. The layman is sufficiently familiar with this subject co know chat, as far as our knowledge goes, quartz is one of the principal objectionable factors in the production of this condition. He should also know that silicosis respects neither geographical nor industrial boundaries. It is as much a factor in some industrial processes (e.g. foundry work, sandblasting) as it is in mines handling ores containing quartz. Its development co a recognizable stage is usually a matter of many years. As yet, its cure is unknown. Its prevention is possible in varying degrees. The layman should also know that the development of fibrosis may be accelerated by breathing in, or living in, any atmosphere containing dust. Few normal adults, particularly those above a certain age, have clear lungs, and fibrosis in varying degrees is noted in the farmer, the steel worker, the clerk, and many others in varied occupations. It is not restricted to miners. Medical and industrial journals, and at times the press, are crammed with data pertaining to this subject, much of which is misinformation. This is particularly true of certain !laces where the preventive and compensation measures for the good o those earning their livelihood in an industry in which silicosis may be contracted are not so far advanced as in our own Province. A great many of these publishings are alarming to the layman. They leave him with the impression that he is taking his life in his hands if he elects to work underground, particularly in a gold mine-that he has at once sold his heritage of health and chat sooner or later he will succumb to the ravages of this ailment. Nothing could be farther from the truth. Actually, under present conditions in Ontario mines, a very small percentage of the men employed ever become impaired by silicosis to the extent chat they must withdraw from the industry. I propose to tell you briefly something of this subject as it affects our mines.

Jan 1, 1937

By H. Ito, T. Takasu

Effects of a mechnochemical treatment to oxide Ni ores have been investigated to enhance the extractive ratio of Ni from them in acid leaching process. High intensity grinding by a planetary boll mill showed strong effect to enhance the extractive ratio of Ni, for example , 10% of extractive ratio of Ni in sulfuric acid leaching(0.05mo1/1,at room temperature) increased to more than 90% with 60min. of planetary boll milling. Effects of additives(sulfur and some oxidants) on the mechnochemical treatment have also studied. Sulfur showed almost no effect to enhance the total Ni extractive ratio but increases the selectivity of Ni extraction. More than a half of Ni could be extracted by water when Ni ore was grinded at addition of Na2S207 in the milling treatment. Some effects of mechnocemical treatments to Ni ore are summarized in this paper.

Jan 1, 2005

By S. S. Teal, W. W. Weber

"AS THE TITLE implies, this paper will deal with the unusual rather than the standard practices as employed . at the property of North Rankin Nickel Mines, Limited. Fortunately •the mining, with the exception of permafrost conditions, and the milling practices, are the normal approaches dictated by the size, type, and character of the orebody. The unusual aspects are linked directly or indirectly to the isolated location and are •principally ancillary requirements or services covering a broad range from climate to supplies and from finance to entertainment. It is our intent to cover the more salient points of interest together with a brief description of the general operation.To understand the primary motivation of the mine, it must be made clear that North Rankin was conceived as a foothold in the Canadian North, that region embracing 40 per cent of the Dominion which ex-tends north of the commercial tree-line and which includes nearly 50 per cent of the Precambrian Shield, our mainstay of Canadian mining. Secondly, this project was born in an atmosphere of premium sales in the nickel markets, assuring a rapid pay-back of the heavy •capital expenditures. And finally, it has •been coddled through the stark reality of a competitive metal market with the hope and trust that the experiences and achievements will lead over the bill to a bigger and better mine in this virgin territory. This is the briefest story of the mine's history, but it pays tribute to the many people who, in thirty years since .discovery, have championed this project."

Jan 1, 1959

By Rene Cane, V. I. Lakshmanan, John Starkey, Richard May

"The Agrium Kapuskasing Phosphate Operation mines and processes up to 6,000 t/d of phosphate ore. Run-of-mine crushing to minus 6 inches is done in a toothed roll-crusher, while grinding is done in a SAG/ball mill circuit with no coarse recycle classification of the SAG mill discharge. The primary grinding mill is an 18 ft. diameter x 9 ft. EGL, 1500 HP variable speed SAG mill and the secondary mill is a 13 ft. diameter x 21 ft. long, 2000 HP fixed speed, ball mill. When hard ore was treated, the SAG mill restricted the tonnage that could be ground. When soft ore was treated, the ball mill and spiral classifier overloaded and restricted throughput.Recommendations from a plant benchmark and an ore hardness testing program, on how to better utilize installed energy in the Agrium SAG mill when treating soft ore, and how to obtain best results when treating hard ore, were checked in a pilot plant investigation in the 3 ft. diameter Starkey-PRO Pilot SAG Mill. Correlation between the ore hardness testing and the results from the 3’ Pilot SAG mill was very good. In addition, the work indicated the results that could be expected for the different ore types when using either smaller SAG discharge grates and/or a vibrating screen with 10 mesh square opening cloth.INTRODUCTIONAgrium Kapuskasing Phosphate Operation consists of a 6800 t/d open pit mine and a concentrator, near the Town of Kapuskasing in Northern Ontario. The two major ore types are sandy ore and cemented ore. Sandy ore is fine, soft and easy to grind in the SAG mill while cemented ore is harder, more blocky and difficult to grind in the SAG mill. The ratio of sandy to cemented ore in the deposit is thought to be in the order of 80:20 but can range as high as 5050, so it was important for the grinding circuit to have the ability to treat sandy ore alone."

Jan 1, 2002

By R. G. K. Morrison

By arrangement between the Ontario Mining Association and Messrs. John Taylor & Sons, Mining Engineers, 6 Queen Street Place, London, E.C.4, the writer was engaged for a period of not more than three months to report on the rockburst situation in Ontario mines. This was later amplified, by mutual agreement, to include, at the expense of detail, visits to the larger camps where rockbursts had not occurred, to get a general picture of conditions and to discuss the subject with operators in their respective areas. Scope of Activities Visits were paid to the following properties for the purpose of enquiry and discussion; the underground workings of those mines marked with an asterisk were visited on one or more occasions: KIRKLAND LAKE * Macassa Mines, Limited * Kirkland Lake Gold Mining Co., Ltd. * Teck-Hughes Gold Mines, Limited * Lake Shore Mines, Limited * Wright-Hargreaves Mines, Limited Sylvanite Gold Mines, Limited Toburn Gold Mines, Limited EAST KIRKLAND & LARDER LAKE Upper Canada Mines, Limited Chesterville Larder Lake Gold Mtng Co., Ltd. Kerr-Addison Gold Mines, Limited Omega Gold Mines, Limited PORCUPINE * Hollinger Consolidated Gold Mines, Ltd. * Mcintyre Porcupine Mines, Limited * Dome Mines, Limited * Buffalo Ankerite Gold Mines, Limited Paymaster Consolidated Mines, Limited Preston East Dome Mines, Limited Pamour Porcupine Mines, Limited Broulan Porcupine Mines, Limited Hallnor Mines, Limited Naybob Gold Mines, Limited Delnite Mines, Limited Moneta Porcupine Mines, Limited DeSantis Porcupine Mines, Limited Coniaurum Mines, Limited SUDURY lnternational Nickel Co. of Can., Ltd. * Falconbridge Nickel Mines, Limited LITTLE LONG LAC AREA * Little Long Lac Gold Mines, Limited MacLeod-Cockshutt Gold Mines, Ltd. Hard Rock Gold Mines, Limited Bankfield Consolidated Mines, Limited Magnet Consolidated Mines (1936), Ltd. à PICKLE LAKE AREA * Central Patricia Gold Mines, Limited * Pickle Crow Gold Mines, Limited UCHI LAKE * Uchi Gold Mines, Limited McKENZIE ISLAND AREA Gold Eagle Gold Mines, Limited * McKenzie Red Lake Gold Mines, Ltd. * Cochenour Willans Gold Mines, Limited RED LAKE * Howey Gold Mines, Limited Hasaga Gold Mines, Limited Madson Red Lake Gold Mines, Limited

Jan 1, 1942

By Donald E. Wakefeld

"The pace at which mining will occur in Northern regions and Arctic lands will depend on the answers to a number of questions. Who are the local aboriginal participants? What land uses are they pursuing? What are their objectives? What is their understanding of the process of mining development? This paper will focus on the last question, communicating the process of mineral development to local aboriginal communities.IntroductionIn the environmental impact hearings for the BHP-DiaMet diamond mine, the smaller Dene Treaty 8 Nation argued for the settlement of its Land Claims as a pre-condition to development. However, the larger Dene Treaty 11 Nation were prepared to permit the mine to proceed on the basis that their people would receive benefits during the construction and operation of the mine.Wherever mining is the significant basis for tax revenues and economic development expectations may be encouraged beyond the realities of the situation. Izok Lake has been known for several decades as a significant mineral deposit but because of its size and the transportation costs involved, it is now a “frozen” ore body. The extent of its mineralization at current metal prices will not support the mining and processing costs without substantial government support for infrastructure and roads. At the opposite side of Canada, Voisey’s Bay clearly satisfies all technical criteria but, nonetheless, two Inuit groups, the Innu, and Métis, have all made LandClaims relating to the mine area.Contrasting the mineral deposits at Voisey’s Bay and Izok Lake emphasizes that the timing of production is dependent on factors such as the grade and amount of reserves, their market price, location and availability of government support. Nonetheless, it is this author’s thesis that given an economic orebody the next most important factor is good communications. It is his view that Arctic mineral development will occur quickly only where good communication has resulted in the trust and mutual respect necessary to implement the mammoth cultural changes required."

Jan 1, 1996

By J. E. Udd

A core sample for this study was taken from the sulphide ore of the Geco Mine. The subsequent research was based on the assumption that a part of the scattering of strength-grade data could be correlated with variations in the chemical and/or mineralogical compositions of the samples. The results demonstrate clear relationships between strengths in tension and compression and the zinc-iron contents of the rocks.

Jan 1, 1977

By D. M. Maijer, S. L. Cockcroft, S. Modak, A. B. Phillion

"A comparison between hydrogen-diffusion-based micro-porosity formation and growth behaviour of two important aluminium foundry alloys, B206 (Al-Cu) and A356 (Al-Si-Mg) is presented in this paper. Specifically, the predicted pore size and pore fraction distribution of these two alloys resulting from directional solidification and identical hydrogen concentration are investigated numerically based on a model proposed by Yao et al. (2011. Met. & Mat. Tran. A. 42A, 4137–4148). This model takes into consideration the initial hydrogen content in the melt, the cooling rate, the partitioning of hydrogen between the solid and liquid phases, and the evolution in solid fraction with temperature. Due to different alloy chemistries, the activity of hydrogen in B206 and A356 are quite different, as are the solidification range and the resulting solidification microstructure. Being a primary alloy, B206 has dendritic microstructure and solidifies over nearly 135°C (505–641°C), whereas A356 contains fifty percent eutectic microstructure, and solidifies over 80°C (533–613°C). This allows a very different behaviour of micropores i.e. the effective pore radius in B206 is quite a bit lower as compared to A356, as is the pore number density. The evolution of local hydrogen concentration in liquid metal is analysed and compared for both the alloys.INTRODUCTION Over the past decades, the demand for materials with enhanced strength-to-weight ratios has significantly increased in the aerospace and automobile industries in order to improved fuel efficiency. For many automotive components, particularly shape castings, the trend is towards replacing ferrous alloys with aluminium alloys. The increase in the use of Al is primarily due to its low density, about one-third that of steel, and its relatively good strength that allows for weight reduction without reducing performance. Presently, Al-Si based alloys (e.g. A356) are the most prevalent due to their good mechanical performance in strength-to-weight ratio and excellent castability (Atwood et.al., 2000). However, superior mechanical properties can be achieved using Al-Cu alloys. For example, the alloy B206 offers a higher strength while retaining excellent ductility (Poirier et.al., 1987)."

Jan 1, 2017

By Clifford S. Gibson

THESE troubled times suggest three reasons for maximum effort to control silicosis: (1) To keep to a minimum the ever-increasing burden occasioned by past deficiencies in this respect. (2) To effect the greatest production with maximum efficiency, which means at the least cost. (3) To preserve man-power in every way. Good control of the silicosis problem aids these aims. Inadequate control hampers all three. Insofar as our knowledge goes, silicosis in Ontario mines is caused by the inhalation of finely particulate quartz. It follows, therefore, that removal of dust containing this mineral automatically erases the cause. The achievement of this ideal is the aim of the mine operator. His best tool to this end is ventilation. This paper discusses mine ventilation from the viewpoint of dust control and it is hoped that in so doing there may result a better understanding of the part played by air in silicosis prevention. No attempt will be made to treat the subject fully. Instead, there will be presented certain salient aspects culled from field observations, the data in all cases referring to gold mines, unless mention to the contrary is made.

Jan 1, 1942

By Dean L. Millar

Measures taken by mining companies around the world to reduce their carbon footprints are becoming increasingly important in the sector securing its social licence to operate. The options for measures reduce to three categories of activity: i) demand reduction by avoiding unnecessary waste of supplied energy, ii) improving the utilization of energy that does have to be consumed and iii) adopting low carbon energy production options?including renewable energy. As well as the environmental imperative, as the prices of electricity, gas and liquid fuels increase, so the economic case for activities i) to iii) gains higher priority, especially in such an energy intensive industry. The specific energy consumption for certain upstream minerals industry operations in Canada is reported to be as follows: underground mining: 99.5 kWh/tonne mined; surface mining: 11.7 kWh/tonne mined; base metal processing: 81.4 kWh/tonne milled; gold processing: 99.6 kWh/tonne milled. Around 508 kWh/tonne (slag) of heat is reported to be available in cooling slag from 1500°C to 25°C; an amount that is simply indicative of the energy intensity of downstream smelting and refining operations. Low carbon, energy saving technology options that are available to mining industry companies lead to projects with return rates that must compete alongside other capital intensive projects considered by mining company boards. Energy projects frequently involve longer payback periods and lower rates of return than those of competing bids for capital, such as those for development of new mineral properties. For energy services companies (ESCOs) that specialize in the financing, construction, and the efficient operation and maintenance of energy projects, the same returns and payback periods may be considered acceptable or even attractive. For the ESCO, the key commercial risk mitigating factor is a securing a long term contract for the supply of energy.

May 1, 2011