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By A. R. Guest, R. Clayton, J. Jakubec

"The potential for mudrushes is a potential hazard that should be evaluated during cave mining studies. Mudrushes are a phenomenon that can have very different origins, but produce the same results: injury, loss of life, damage to property, excess dilution, production delays, or mine closure. Although mudrushes are more common in cave mines than other mines, any mining activity that enables the accumulation of fine particles and water is susceptible to mudflow. This paper describes the process developed by the authors during the past decade to evaluate the risk of mudrushes, specifically in caving and sublevel caving mines.RÉSUMÉ Un danger potentiel qui devrait être évalué durant les études d’exploitation par blocs foudroyés est la possibilité d’afflux de boue. Le phénomène des afflux de boue peut avoir des origines très diverses; les résultats sont cependant les mêmes : des blessures, des pertes de vie, des dommages à la propriété, une dilution excessive, des délais de production ou des fermetures de mines. Bien que les afflux de boue soient plus fréquents dans les mines exploitées par blocs foudroyés, toute activité minière qui permet l’accumulation de particules fines et d’eau est sujette à des coulées de boue. Le présent article décrit le processus développé par les auteurs au cours de la dernière décennie pour évaluer le risque d’afflux de boue, surtout dans les mines exploitées par blocs foudroyés et par sousniveaux foudroyés."

Jan 1, 2016

By Sunil S. Gandhi

"Uranium occurrences are widely distributed in tuffaceous-argillaceous beds and abundant rhyolitic volcanic rocks of the upper Aillik group, which is more than 3 km thick and over 125 km by 40 km in areal extent. They include partially developed Kitts and Michelin deposits, containing 1560 and 7366 t U respectively.Uranium occurs mainly as disseminated fine pitchblende grains in beds and lenticular stratabound zones, and rarely as coarse pitchblende aggregates and thin veinlets. The Kitts deposit and ten other occurrences are in the argillaceous-tuffaceous beds within a steeply dipping stratigraphic zone, less than 50 m thick and over 20 km long, at the base of the upper Aillik group. The occurrences hosted by the rhyolitic rocks, numbering over fifty and including the Michelin deposit, are in elongate structural-stratigraphic belts or zones, and are characterized by a pronounced enrichment of soda and depletion of potash associated with mineralization. The mineralized zones are affected to a varying degree by Hudsonian deformation, metamorphism and granitic intrusions.The uranium mineralization is interpreted as genetically related to the felsic volcanism, involving syngenetic deposition in argillaceous-tuffaceous beds and epigenetic emplacement in rhyolites. The volcanic activity occurred 1855 ± 5 Ma ago according to a preliminary U-Pb zircon date on porphyritic rhyolite. Pitchblendesfrom the Kitts and Michelin deposits and a few other occurrences in rhyolites have yielded nearly concordant dates in 1810 to 1730 Ma range. They reflect resetting of isotopic equilibrium at the time of Hudsonian deformation. Other isotopic data on pitchblendes and galena from veins and aggregates .in the south near the 'Grenville Front' indicate local redistribution of uranium and radiogenic lead at the time of Grenville Orogeny approximately 1100 Ma ago."

Jan 1, 1986

By M. Takebayashi, M. Shingu, H. Nagai, T. Nakai, S. Asano

The Toyo Smelter and Refinery, owned by Sumitomo Metal Mining Co., Ltd. (SMM) is located in the coastal zone of Saijo City and Niihama City, Ehime Prefecture, Japan. The refinery has been producing copper, sulfuric acid, and precious metals such as gold, silver, and PGMs. Previously, the process of precious metals recovery was a combination of pyrometallurgy and an electro-refining process with the conventional cupellation for around 400 years. However, this process had some major problems such as non-efficient recovery of valuable metals, high environmental risk by pyrometallurgy, high cost for maintenance of equipment and so on. In order to solve these problems, a thorough hydrometallurgical process for precious metals refining using chlorine leaching technology was originated and developed by Sumitomo and thereafter commercialized in 2004 at Toyo Copper Smelter and Refinery. This new process enabled shorter-term recovery of gold and manpower saving, and occupational safety and working conditions have also been improved. Superiority over the existing hydrometallurgical processes was also confirmed, for example by the achievement of 99.99% pure silver production without an electro-refining process. This paper summarizes the hydrometallurgical technologies for precious metals recovery such as chlorine leaching of copper anode slime for silver recovery, solvent extraction (SX) for gold recovery, and ion exchange (IX) for PGMs recovery. It also presents a unique silver purification process. INTRODUCTION Sumitomo Metal Mining Co., Ltd. (SMM) produces copper, precious metals and rare metals as by-products at the Toyo Copper Smelter and Refinery, and nickel and cobalt at the Niihama Nickel Refinery. Precious metals contained in nickel ore are also separated and refined at the Toyo Refinery after concentration. SMM has been refining precious metals using the pyrometallurgical method. In recent years, we have revamped the separation and refining process of precious metals dramatically by making use of advanced hydrometallurgical and engineering technology developed in the company. In this paper, we introduce the history of development and techniques of this process, and also introduce in detail the technologies of gold refining, PGMs recovery, selenium recovery, and silver refining which have been particularly difficult to achieve.

Jan 1, 2019

By M. N. Collison

"In 1960, with the opening of the Chisel Lake mine near Snow Lake, Manitoba, the Hudson Bay Mining and Smelting Co., Limited, commenced a new phase in their mining operation -that of bringing ore to Flin Flon over 100 miles of railroad.The schedule of operations required to accomplish this, together with an outline of some of the problems of handling ore at 40° and 50,0 below zero, are discussed. The facilities required to thaw and unload from twenty to fifty cars per working day are also described."

Jan 1, 1966

By G. J. Borbely, E. A. Devuyst, V. A. Ettel

"A new method for oxidative destruction of cyanide in industrial waste waters and slurries, such as gold mill barren liquors, tailing slurries and flotation tailings has been developed at the Inca research laboratories. Rapid decomposition of cyanide and related species is attained by treating the waste waters with a mixture of S02 and air at controlled pH and in the presence of a small amount of copper which acts as a catalyst. The approach selectively oxidizes cyanide and metal cyanide complexes, and also removes iron cyano complexes which are not removed by alkaline chlorination.The new method is shown to be less reagent intensive and therefore more economical than alkaline chlorination for treating gold mill and flotation waste waters. INTRODUCTIONOver 90% of the gold mined in Canada is extracted from the ore by ""cyanidation"". Wastes from the process consist of tailings which contain free cyanide, cyanide combined with heavy metals, thiosalts and thiocyanates. Because of the concern over the effect of toxic cyanides on the environment, all cyanide containing effluents will have to be treated in the future to meet certain government set concentration limits."

Jan 1, 1982

By J. Stiksma, R. Kalanchey, M. J. Collins, G. Owusu, R. Raudsepp, K. R. Buban, L. A. Barta, L. Masters

This paper describes the results of testwork for the treatment of Ambatovy laterite by an acid pressure leach process, with recovery of the soluble nickel and cobalt values as mixed sulphide intermediate by precipitation with hydrogen sulphide, and subsequent refining of the mixed sulphide to nickel and cobalt metals. These process development studies were carried out primarily in 2004, as part of a bankable feasibility study for the Ambatovy Nickel Project.

Jan 1, 2004

By H. E. Lake

VERY EARLY in the initial stages of underground development work at Eldorado's Beaverlodge operation, the decision was made to use mill tailings as a backfill product. Mining and milling commenced in June, 1953, using locally available sand as backfill, while test work and installation of a plant was carried out to prepare ?and deliver the tailings to the mining areas. The first use of tailings was made in February, 1954, a sandslime separation being carried out with hydraulic cyclones. To date (January. 1956), approximately l 40,000 tons of fill have been used in the stoping areas, providing very effective support in a 50 deg. Vein system of cut-and-fill mining. The recoverable portion of the mill tailings amounts to 40 to 45 per cent, which has resulted in a product giving a percolation rate of 6 to 10 inches per hour. Owing to the fact that Eldorado has milled from 15 to 2 5 per cent more ore than it has mined, through the purchase of custom ore, the degree of control on the sand-slime separation has not been as critical as it might normally be when the filling operation must depend only on the tailings from ore mined. A description of the conditions involved and of the plant as finally installed is given below. It might be mentioned here that, with the impending increase in milling capacity from 700 tons to 2,000 tons p.er day, the present plant will be considerably altered within the ensuing year to handle the increased tonnage and distribution.

Jan 1, 1956

By Xuanxue Mo, Kaihui Yang

"The Laochang mine, located in the Sanjiang area of southwestern Yunnan Province of China, is a volcanogenic massive Pb-Zn-Cu sulfide deposit. It is hosted by a pyroclastic sequence of Early Carboniferous age, namely the lower member of the Yiliu Group, which was intruded by syenite and rhyolite porphyry. The volcanic suite is basaltic or basaltic-andesitic in composition, has alkaline affInities, and is associated with the initial rifting along the margin of the Baoshan-Shanstate continental microplate (Yang, 1989). The ores are typically Pb>Zn>Cu in composition, averaging 3.820/0 Pb, 3.51% Zn, from 0.01% to 1.85% Cu (0.107% av.), a high average content of Ag (113 glt) and recoverable amounts of Au, n, Gd, Ga, Ge, In. A massive sulfide zone, in which lenticular and stratiform orebodies are localized in a sulfide-<:arbonate-silica shale unit or sulfidic tuffIte horizon that usually overlies coarse-grained pyroclastic rocks, is underlain by a stringer sulfide zone developed in a subvolcanic intrusion or volcanic sequence. The sulfIde mineral assemblages, from the top to the bottom of the deposit, are: realgar + orpiment - galena + sphalerite + pyrite - chalcopyrite + pyrite + pyrrhotite + arsenopyrite. Oxide and sulfate minerals occur rarely in the massive ores. The massive ores are generally fme-grained and banded, but coarse-grained ore, colloform and framboidal texture, and growth-zoned pyrite and sphalerite are common. Sedimentary features such as graded bedding, brecciated and deformed ore clasts, and chaotically emplaced blocks, are well preserved, indicating that the massive orebodies have undergone slumping and displacement. Alteration is weak in the hanging-wall rocks, but strong in the stringer zone. Two distinctive alteration zones have been identifIed: the upper zone, characterized by an assemblage of quartz, carbonates, chlorite, albite, zeolite and sericite, and the lower zone containing diopside, tremolite, actinolite, gamet, clinozoisite, and epidote.The general features of the Laochang deposit are in accord with the descriptive model of VMS deposits (Lydon, 1984). However, it falls into neither the Zn-Cu group nor the Zn-Pb-Cu group chemically (Franklin et al., 1981). The depositional setting of the Laochang deposit is quite different from Cyprus or Besshi-type massive sulfide deposits. Laochang is hosted by alkaline lavas that were erupted in a submarine continental rift. Although some features of the Laochang deposit are similar to those of Kuroko-type deposits, there are remarkable differences in the alteration mineral assemblage, the proportion of ore-forming elements (lead enriched) and the amounts of oxides and sulfates. These suggest corresponding differences in ore fluid composition and the associated ore-forming environment. Thus, the authors suggest that the Laochang deposit may be a distinct type of VMS deposit."

Jan 1, 1993

By Jon A. Carlson, W. Scott Williams

The EKATI"" Diamond Mine commenced operation in October 1998. It is operated by BHP Diamonds Inc., which is a part of the Non-Ferrous and Industrial Materials Division of BHP Minerals, a business unit of BHP Company Ltd. of Melbourne, Australia. The EKATI"" Diamond Mine is a joint venture of BHP Diamonds Inc. (51%), Dia Met Minerals Ltd. (29%), Charles E. Fipke (10%) and Dr. Stewart L. Blusson (10%). In December 1993, an office was opened in Yellowknife, Northwest Territories specifically for the then Northwest Territories Diamonds Project (EKATI"" Diamond Mine) development. EKATI"" Diamond Mine is located 300 kilometres northeast of Yellowknife and 200 kilometres south of the Arctic Circle in the Northwest Territories of Canada (Figure 1 ). The site is located in a remote tundra area of continuous permafrost, north of the tree line, which is part of the Canadian Shield. Wekweti (Snare Lake), a Dogrib community approximately 180 kilometres southwest of the project, is the closest neighbour. The mining area and facilities lie within the 10 960 hectares land leases held by the joint venture. The total claim block (core zone and buffer zone joint ventures) covers 344 000 hectares. To date, more than one hundred kimberlite pipes have been identified within the claims. Five of these provide the basis for the present mine plan. Total capital investment in the project is over C$700 million. At full production employment will be about 600, including employees and long-term contractors, with over 33% being Aboriginal from the Northwest Territories.

Jan 1, 2001

By J. R. Johanson, A. W. Jenike

"A solid flows out of a bin provided that the outlet is sufficiently large so that stable obstructions to flow do not develop. The geometry and surface finish of a bin and the construction of the feeder determine the type of flow pattern which then develops within the bin. The pattern, in turn, affects the uniformity and consistency of the stream, segregation, caking, degradation, live capacity and the action of level measuring devices.In most bins now in operation, material flows toward the feeder through a channel which forms within the stationary solid. This is referred to as funnel flow. If the hopper of the bin is sufficiently steep and smooth and the feeder capable of drawing material across the whole area of the outlet, all the solid flows whenever the feeder is in operation; this is referred to as mass flow. Mass-flow bins are usually far superior to funnel-flow bins; their initial cost is also usually higher.The paper describes the design criteria used in deter-mining the minimum bin outlet needed for flow and the bin geometry needed for mass flow."

Jan 1, 1970

By J. S. Scott

"The Quemont property comprises 640 acres lying directly north of and adjoining the Noranda (Horne) mine. During 1926 to 1928, United Verde Extension Mining Corporation sank a shaft 235 feet and did 3,000 feet of development work on the 215-foot level. Between 1929 and 1930, Quemonr Mining Corporation deepened the shaft to 926 feet, and did further lateral work and drilling on the 500- and 900-foot levels. This work was confined to an area close to the south boundary and met with little encouragement.Following a period of idleness a magnetic survey was made in the winter of 1944, followed in the summer of the same year by some 6,000 feet of drilling. The first successful hole was drilled in February, 1945, from the ice of Osisko lake.To the time of writing, 131,000 feet of drilling, surface and underground,have indicated a large tonnage of gold-silver-copper-zinc ore, and although some knowledge of the geology and structure is emerging, it is too early to draw definite conclusions. The following brief description deals only with those structural features that are reasonably well indicated."

Jan 1, 1954

By W. G. Miller, J. D. Scott, D. C. Sego

ABSTRACT An overall study was conducted to evaluate the properties and processes influencing the rate and magnitude of consolidation for oil sands fine tailings produced using different extraction processes. As part of the overall study, a comprehensive description of physical and chemical characteristics of fine tailings generated by caustic and non-caustic processes was carried out. Ultimately, the influence of these fundamental properties on the compressibility, hydraulic conductivity and shear strength properties of the fine tailings was assessed. The characteristics of the fine tailings are presented in terms of index properties, mineralogy, specific surface area, water chemistry, liquid limits, particle size distribution and structure. A difference in water chemistry was concluded to be the cause of substantial differences in particle size distributions and degree of dispersion of the comparable caustic and non-caustic fine tailings. The degree of dispersion was consistent with predictions for dispersed clays established by the sodium adsorption ratio (SAR) values for these materials. A linear variation of increasing dispersion with increasing SAR up to a SAR value of about 40 has been suggested, above which fine tailings are completely dispersed. The observed dispersed or flocculated structures (viewed using a scanning electron microscope) supported the predictions based on SAR values.

Jan 1, 2010

This paper states how alloy and welding advances have made possible the rapid development of the use of aluminum in the construction of equipment for earth moving and off -highway rock hauling. The main details are given regarding the construction and field testing carried out on an aluminum prototype body. The test results of strain gauge readings are analysed, and a description is given of how these have been applied in subsequent designs. The increase in the number of aluminum units put into the various types of service in Canada, as well as the problems encountered, is described, and the experience gained from five years of field service is discussed in some detail. An assessment is also made of the durability of the e units. The economics of using aluminum, together with the current development position, are reviewed, and predictions are made for considerable future increases in the use of aluminum units in open-pit and off-highway operations.

Jan 1, 1964

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 W. W. Heywood

"IntroductionCIRCULAR structures on the Arctic islands were first noticed early after World War II. During the indexing of the 1950 Royal Canadian Air Force photographs their occurrence was brought to the attention of the Geological Survey of Canada by Mr. W. B. Waugh, Surveyor General. As a result, I. C. Brown ( 195l) of the Geological Survey of Canada studied the air photographs of these structures and discussed theories that might explain their origin. The author, as a member of the Geological Survey of Canada, spent several months in 1952 and 1953 in reconnaissance study of the geology of Ellef Ringnes island, using the Isachsen meteorological station as a base. Twelve days in the summer of 1953 were spent mapping the Isachsen dome and adjacent areas. The Isachsen dome, one of several similar structures occurring on Ellef Ringnes island, is situated 35 miles southeast of the meteorological station.PhysiographyEllef Ringnes island is a mature, stream dissected plain having an average elevation of about 400 feet. The surface of the plain is undulating with a relief of about 150 feet; only a few of the numerous streams that form a dendritic drainage pattern have eroded valleys this deep. Long, low, cuesta escarpments cross' the plain, which is underlain by sedimentary rocks of Lower Cretaceous and possibly younger age. The sedimentary strata have a low regional dip to the southeast; exceptions are found in the vicinity of the domes, where the strata are up-turned, and in the plateau region, northeast of Deer bay, where they are flat lying. The plateau, which is underlain in large part by basalt, is deeply dissected and has an average elevation of 1,000 feet."

Jan 1, 1955

By Ralph W. Edie

"IntroductionTHIS PAPER deals with chemical and mineralogical changes in wall-rocks associated with pitchblende mineralization in the Gold-fields area of Saskatchewan. The localities at which the rock specimens studied were collected, and descriptions of the various rock-types referred to, are given in a previous paper by the author (5).The geological field work upon which this paper is based was carried out while the writer was employed by the Eldorado Mining and Refining Company during the summers of 1948, 1949 and 1950. The laboratory work§ consisted largely of quantitative spectrographic analyses for both major and minor elements, supplemented by an examination of 250 thin sections of both altered and unaltered rocks.Character of the AlterationHydrothermal alteration, with associated pitchbende mineralization, is widespread in the Goldfields area of Saskatchewan. The most intense alteration is restricted to the immediate vicinity of fault or breccia zones, but large areas are affected to a minor extent.In detail, the relationship between alteration and pitchblende mineralization is complex, as individual veins do not in general have separate alteration halos. Pitchblende generally occurs in gash-like calcite veins or stringers in wide, fractured zones associated with faulting. Large, lenticular and tabular masses of slightly to intensely altered rock occur in the same wide fracture zones as the mineralized veins. However, vein deposition appears to be-long to a later fracturing period, after hydrothermal alteration was more or: less completed. Generally, the veins transect and are confined to highly altered rock, but on the other hand many highly altered zones intersected in diamond drill-core are barren of mineralized veins."

Jan 1, 1953

By Z. Luo, China University of Mining & Technology, C. Duan

"The magnetic separation removal rate of pyrite could be improved effectively by increasing the susceptibility of pyrite. The electromagnetic characteristics and absorption response performance of high-sulfur fine coal were studied in strengthening the susceptibility of pyrite. In the process of treating the sample through the microwave, electromagnetic energy could be converted into heat energy due to dielectric loss and magnetic loss. The RL(dB) was evaluate the performance of absorption response of coal. The microwave improved the susceptibility was in ultra-high frequency region, which is the most natural resonance. The absorption fine coal to microwave was strengthened and microwave energy was improved by adding the magnetite powder with double loss characteristics as the microwave absorber. The dielectric properties and permeability characteristics of the fine coal trend were investigated by maxing magnetite powder. The microwave absorption in different coal thickness was surveyed through the reflection of energy loss.INTRODUCTIONMicrowave desulfurization is one of the most important research directions (Haque, 1999; Makul, Rattanadecho, & Agrawal, 2014; Su, Tang, Zhang, Jing, & Bai, 2014). The working principle of microwave absorption response can be briefly described as the interaction of the sample with microwave energy, which will result in the microwave energy converting into heat energy loss (Keangin & Rattanadecho, 2013). For specific samples, the polarization effect includes multiple polarization mechanisms(Meikap, Purohit, & Mahadevan, 2005). Different polarization mechanisms have different occurrence time and dominant mechanisms. Meantime, energy consumption will be occurred during the process of polarization effect (Chelgani & Jorjani, 2011; Rowson & Rice, 1990) . The absorption of microwave energy in the fine coal is a process of electromagnetic response (Znamenácková, Lovás, Mockovciaková, Jakabský, & Briancin, 2005). Microwave transfers the electromagnetic waves into the heat energy by microwave dielectric loss and magnetic loss for achieving the absorption of microwave energy in the treatment of samples (Lee, Kim, Kim, Chung, & Kim, 2004). The additive magnetic medium is Fe3O4 belonging to microwave energy absorber of double loss medium (Uslu, Atalay, & Arol, 2003)."

Jan 1, 2016

By A P. Powell

This paper deals with the power plant at Cassiar Asbestos Corporation Ltd., Cassiar, B.C. It discusses the units installed in the plant, the distribution of power and the costs involved. The efficiencies and economics of this power plant are considered to be somewhat better than average. Introduction C ASSIAR Asbestos Corporation&apos;s power plant had its inception in 1952 with a 15-by 15-ft. log cabin containing two International Harvester diesel generator sets of 50 kw. total generating capacity. Over the years, it has grown to its present size -an 80 by 82 ft. by 35-ft.-high rigid-frame Butler building housing eight 2,300-volt diesel generating sets, a 2,300-volt distributing switchboard, a 550-volt auxiliary panel, three air compressors, six heat exchangers and other related equipment. The units in the power plant, numbered according to their order of placement, are rated as shown in Table I. The total generating capacity of the plant is 3,673 kw. All of the generators are of the open vertical design except that on No. 7 engine,

Jan 1, 1965

By R. J. Allan

"CANADA HAS A GREATER LAKE AREA than any other country. Discountin the Great Lakes, this fresh-water area, mainly in the Canadian Shield, is listed as approximately 300,000 sq. mi. Densities of lakes range up to 7,500 in a 5,294-sq. mi. area of the Shield, southwest of Reindeer Lake, Saskatchewan. Five areas chosen randomly from the Shield (Figure 1) contained sufficient lakes to provide samples at a density of at least one per 10 sq. mi. Regional geochemical surveys in the Appalachian area (Nova Scotia, Boyle et al., 1958; New Brunswick, Boyle et al., 1966) and in the Cordilleran area (Yukon, Gleeson, 1965) of Canada and in many other areas of the world have relied heavily on analyses of stream sediments. These surveys show that sampling of material related to the drainage system reflects the over-all trace element content of the rocks and surficial deposits in the drainage basin. In the Shield, the classic types of dendritic (and other) stream systems found elsewhere in the world are very rare. However, impeded and disorganized stream systems that abound with lakes can provide the exploration geochemist with an ideal composite drainage system sample in the form of lake sediment. This paper attempts to demonstrate the feasibility of, and review the theory and problems involved in, the use of lake sediment as a regional geochemical exploration medium. Most of the references to field examples are taken from a regional survey using lake bottom sediment as the sample medium over 1,500 sq. mi of the Coppermine basalt group and adjacent rocks (Figure 2). During this regional survey, detailed sampling of several lakes was carried out and the results are referred to at appropriate places in the text."

Jan 1, 1971

By C. Robinson

The Diavik Diamond Mine is located in one of the most remote and forbidding places in the world, 220 kilometres south of the Arctic Circle and on the bed of a vast northern lake, Lac de Gras. A single road, built out of ice and crossing frozen lakes, connects the mine with other operations and Yellowknife, the capital of the Canada&apos;s Northwest Territories. Diamonds were first discovered in the Lac de Gras region in the early 1990s, and construction of the Diavik Diamond Mine was completed in 2003. Diavik currently mines three kimberlite pipes. Open pit mining has now concluded and all three pipes are mined using underground mining methods. In early 2010, Diavik began mining and processing initial ore from its new underground mine; underground mining operations are expected to continue beyond 2020. The initial mine ventilation system was an exhausting (pull) system with fresh air supplied by a fresh air raise and a main ramp. Return air was exhausted via two raises and a secondary ramp. The system had a total flow capacity approximating 401-411 m3/s. With planned increased production and with changes in mining method, it has been proposed to change the mine ventilation system to a positive (forcing) ventilation system in order to meet projected increases in flow requirements of 566-708 m3/s. Extensive engineering work was developed in order to successfully achieve the changes in system configuration. In the proposed configuration, the main ramp is in an exhaust configuration and exhaust raises are converted to fresh air raise. A number of system implementation options were investigated and phased plans for system execution have been developed. The proposed changes to the ventilation system are substantial and involve extensive construction work. Work was commenced in 2011, each planned phase has been successfully completed to date, and system changes continue today in order to achieve complete system flow reversal and increased flow distribution. This paper details the design of the modified ventilation system and commissioning work which will allow the mine to meet its future production targets.

Aug 1, 2013