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By H. Kalsi

"IntroductionRoyal Oak Mines Inc. is currently operating the Parnour No.1 mine located 10.5 miles east of Tinunins, adjacent to Highway No. 101. The operation produces gold ore at a rate of 3300 tpd. A variety of mining methods including bulk open stopes with ITH drilling, narrow vein panel, longhole and open pits contribute to produce 1.2 rnillion ore tons annually. The milling process requires water at an average rate of 1 rnillion gallons per day (700 U.S. gpm). The Pamour No.1 mine has historically had two major problems with regard to water control. The flfSt is the underground pumping system's inability to handle excess inflows of water generated from spring thaws. When the thaw takes place over a short period of time, large inflows of water are created which quickly migrate underground and sometimes result in the loss of the lower loading pocket. During the spring runoff the pumps at Parnour No.1 work continuously for 24 hours at a rate of 1200 U.S. gpm. The system was further taxed in 1991 when the Hoyle mine was connected to the Parnour No. 1 mine and whatever excess capacity the pumping system had for the spring runoff was taken up handling the inflow of mine water generated by the Hoyle.The second problem facing the mine was the lack of water for the mill during the severe cold winter months and dry summer months. At those periods inflows of water into the mine decline and the underground water normally pumped to the mill is severely decreased. In times of dry spells mill personnel increase the water diversion from the Three Nations Lake in order to meet water demands and maintain tonnage throughout. In essence, the mine was going through an annual ""feast or famine"" situation and a solution was needed.A number of options were considered but were narrowed down to the two most practical. The first was to modify the existing pumping system and increase its capacity in order to handle the excessive runoff during spring thaw. This involved a heavy capital expenditure and would have caused additional operating costs (i.e. increased hydro). The option chosen by the management was to divert the spring runoff into an unused section of the mine called The West End. A bulkhead placed at the 2400 level would provide an ultimate underground water storage potential of 150 million gallons. This would also cut down the load on the existing pumping system, save electric consumption in pumping and provide water storage which could be used for milling during the two dry spells. Pumping stored water from the mine could be scheduled for off peak hours to take advantage of lower power rates. To meet these objectives an underground bulkhead capable of withstanding high water pressure up to 2000 ft head (866 psi) was constructed in the spring of 1992. The bulkhead site was at the 2400 level at the Pamour No.1 mine. A major consideration was the requirement to construct a safe bulkhead and to minimize water leakage from the bulkhead.Figure 1 shows the bulkhead location."

Jan 1, 1994

By W. Griffith

"While oxalic acid precipitation practices are commonly applied on purified rare earth elements (REEs) pregnant leaching solutions (PLS), few efforts have been reported using oxalic acid (OXA) to recover REEs directly from untreated PLS. High oxalic acid demand is the most significant issue in all these direct oxalic precipitation (DOP) practices. Preliminary research on DOP of REE from a dilute PLS originating from an acid bake followed by water leaching was conducted. At 75°C, the oxalic acid demand was between 12 and 18 times the stoichiometric requirement for complete REE precipitation. Conducting DOP at 25°C had superior REE recovery but the product purity and filterability declined. Between 75°C and 100°C, REE recovery increased with increasing temperature. When sodium hydroxide was used to adjust the pH during DOP, in the range of 0.5 to 1.5, higher pH benefited REE recovery. Using ammonium hydroxide in place of sodium hydroxide, the REE recovery was reduced by close to 5%. Sodium chloride addition to the PLS was also investigated and the results showed that at both 75°C and 25°C, the REE recovery was enhanced substantially. At 25°C, when the oxalic acid addition was controlled at 4.7 times the stoichiometric requirement, the overall REE recovery reached 95% with the addition of 240 g/L NaCl. Other reagents such as KCl, NH4Cl also showed significant enhanced REE recovery at the same oxalic acid addition. The addition of sodium sulphate appeared to largely enhance the precipitation of LREE but inhibited the formation of HREE oxalate. All results indicate the formation of rare earth double salts may play an important role in REE DOP sulphate media.INTRODUCTIONThe conventional routes for recovering rare earth elements (REEs) from a sulphuric acid pregnant leaching solution (PLS) involves an initial purification step for removal of iron, aluminium for example by precipitation through neutralization, followed by precipitation of REEs as hydroxide, oxalate or carbonate salts, or by bulk solvent extraction for REE recovery (Xia, 2013). Another route was used by Bayan Obo in their historical flowsheet, where the PLS was first subjected to double sulphate precipitation, then the remaining REEs, mostly heavy rare earth elements (HREE), were recovered by oxalate precipitation (Li, 2011)."

Jan 1, 2016

By Thom Mambe, Angelo Fernando

The objective of this work was to identify key parameters related to the reduction of the sulphur content in ammonium diuranate (ADU), and the identification of solid products being formed under various operating conditions. A laboratory-scale, continuous ADU precipitation circuit was assembled using a glass reactor vessel immersed in a temperature-controlled water bath. A pre-prepared uranium feed solution was fed continuously using a peristaltic pump. Anhydrous ammonia mixed with compressed air was metered and pumped using a double-headed peristaltic pump. An over-head mixer was used to keep the solids in suspension. The precipitated ADU slurry was removed from the reactor at the same flow rate as the feed solution. The slurry was sampled to generate ADU solids for chemical and physical analysis after four hours of continuous operation to ensure steady-state conditions. The following variables were studied to determine their influence on the sulphur content in the resulting ADU. (a) sulphate:uranium molar ratio in the reactor (1:1, 1:5, 1:10 and 1:20) (b) precipitation pH ( pH 6, 6.5, 6.9, 7.5 and 9) and (c) precipitation temperature (40C and 60C) A total of 18 tests covering the above parameters were conducted, and the results indicated that the sulphur content in the resulting solids was highly dependent on the reaction pH. Out of the pH levels tested, tests completed at pH 6.9 and 7.5 generated solids containing the lowest sulphur contents, between 0.5 to 1.5% S uranium basis (UB). The sulphur content in solids was found to vary linearly with the sulphate:uranium ratio in the feed solution, showing a statistically valid correlation. The impact of temperature was minor between 40°C and 60°C, with a slight advantage at higher temperatures. Tests at a sulphate:uranium ratio of 1:1 produced solids with the lowest sulphur contents. The influence of pH or temperature on sulphur content in solids was almost non-existent at this sulphate:uranium ratio. Precipitation pH is the major factor influencing ADU sulphur content, followed by the uranium to sulphate ratio.

Jan 1, 2020

By J. Doucet, C. Price

In an industrial setting, operational changes are continually introduced, driven by new technologies or changing economics. Because of day-to-day variability, quantifying the impact of these changes based on metallurgical performance requires long trial periods to achieve statistically significant results. Tools and techniques developed by the mineral processing group at McGill University have allowed for direct measurement of process variables (e.g., bubble size, gas and solid holdup). Two case studies are described where direct measurement techniques were used to evaluate: a) a new rotor stator mechanism; and b ), the introduction of a new frother type. Application of these methods has accelerated the evaluation of process changes and improved confidence in results.

Jan 1, 2009

By A. M. Bell

General Summary THIS paper attempts to describe in a preliminary and general manner the nature of certain copper discoveries now being developed by Gaspe Copper Mines, Limited, in Holland township, in the interior of the Gaspe peninsula. Some copper mineralization appears to have been known here at the time of the earliest French explorations, was rediscovered in 1921, and has been under intermittent development by Noranda Mines since 1938. In the last two years discoveries have enhanced the picture so that the deposit now promises to develop into one of the important Canadian copper producers. As ideas are constantly changing with continuing development, any picture given now is very partial and tentative and must be subject to future revision. The nature of these copper occurrences differs from others known in eastern America. In many respects they have unique features but they are most closely akin to some copper deposits found away from the intrusive rocks in the porphyry copper districts of the western United States. The most important orebodies are replacement deposits in a limestone horizon in which the ore gangue is converted to skarn. These lie at considerable distances from any known intrusive but seem to have been derived from a buried stock of granite that intrudes the sedimentary rocks of Lower Devonian age. This intrusive has produced alteration effects in the overlying rocks that may afford a key to locating other ore areas in the Peninsula.

Jan 1, 1951

By Neil Camarta

$6 Billion Dollar Education ?? Construction is like war ? you need a command and control organization ?? A strong Owner?s team is a must ?? Smaller is better ? break the project into bite size chunks ?? New technology is risky ? lots of construction and start-up risk ?? Safety can be successfully managed ?? Don?t expect contractors to ?work well together? ?? Never, ever let Mining Engineers run stuff than can catch fire

May 1, 2008

By Brian Hart, Zhe Chen, Liuyin Xia, Mana Pourdasht, Stamen Dimov

"Gold losses related to carbonaceous matter (CM) during processing are a significant problem in the gold processing industry. Inherent CM in gold ores can behave similarly to activated carbon in its ability to adsorb gold cyanide. This phenomenon is termed preg-robbing as the surface adsorbed gold cannot, for the most part, be recovered. Research has identified that gold adsorption by inherent CM is linked to the specific surface area, pore structure, degree of C disorder and surface functional groups. One of the strategies to inhibit CM preg-robbing prior to leaching is a chemical oxidation; a process linked to modification of the surface functionality. In this study, the variability in gold cyanide adsorption due to oxidation with different reagents has been investigated. Variability in gold cyanide adsorption by CM is examined in relation to structural and surface modifications using TOF-SIMS, XPS and Raman spectroscopy.INTRODUCTION A major obstacle for effective gold recovery during carbon in leach (CIL) or carbon in pulp (CIP) processes carbonaceous gold ores is the presence of carbonaceous matter (c-matter) which has the ability to adsorb, or preg-rob gold from the cyanide leach solution. It can be responsible for poor recoveries as the carbonaceous materials (CMs) within the ore competes with activated carbon used during the leaching and adsorption phase of processing (Cay, 2014). Preg-robbing capacity can vary significantly with mild preg-robbing ores showing absorption capacities of less than 1 g Au/t ore, while severe preg-robbing ores may have CM with the capacity to preg-rob more than 500 g Au/t ore (Dunne, 2007). Research by a number of groups have shown that the degree of C disorder has some influence on the ability of the carbonaceous material to adsorb Au(CN)2- (Miller et al, 2005, Helm et al, 2009, Hart et al, 2010). It is also apparent the adsorption characteristics of carbonaceous material is affected by changes in surface chemistry (Dimov, 2016). Various treatment including; flotation to remove the carbonaceous material (Wills, 2010), addition of surface blinding agents (for example kerosene) to passivate or blanket the carbon surfaces (Dimov, 2016), addition of strong adsorbents (eg. activated carbon or resin) to compete with the carbonaceous material and passivation or surface coating by oxidation (pressure, roasting, chlorination and biological oxidation), have been employed prior to leaching in an attempt to minimize the gold losses (Dunne, 2013)."

Jan 1, 2017

By R. D. Mollison

"Ecstall Mining Limited was formed to operate the Kidd Creek mine, discovered by Texasgulf Incorporated in 1961 the orebody is geologically very complex, containing rich values of zinc, copper, silver and lead. The first phase of the operation involved an open pit, railroad and concentrator complex, which was under construction in 1965 and began operations in late 1966. The open pit, with rim dimensions of 2,000 by 1,000 feet, was computer-designed and highlights excellent wall control and efficient ore extraction and grade control. The railroad was built over the worst type of muskeg country, but it has been well maintained, resulting in an uninterrupted supply of ore in the trains. The 10,000-tpd concentrator, located 17 miles from the mine, is highly instrumented and automated. It features computer control of reagents and, in addition to the copper, zinc and lead flotation circuits, has a modern gravity tin plant. The concentrator is large, because very fine grinding is required for good metallurgy and nearly 2,500 tons per day of concentrates are produced. In 1969, work was started on the underground mine to take over from the open pit; it began partial production in mid-1973. The mine is highly instrumented, has a ramp from surface, a high-production shaft, an underground gyratory crusher and an efficient orehandling system, and employs the latest mining techniques. The electrolytic zine plant, rated at 120,000 tons of slab zinc per year, started operation in April, 1972, with batch leaching and purification circuits. It has been converted to continuous leaching and is now in the process of converting to continuous purification. Further modernization and automation will be carried out in the next few years. Five service departments support the five operating departments. These are maintenance, engineering and technical services, geology, administration and employee relations. How these ten departments function and work together using the most advanced technology to produce an efficient operation is the main theme of the Ecstall Story."

Jan 1, 1974

By F. W. Gray

IN 1922, the writer communicated to the Institute a paper entitled The Development of the Coal Industry in Canada (1), which summarized the considerations set out in a series of papers (2) concerned with coal-mining in Canada which he had presented in 1920 and 1921. This paper contained a forecast by decades, commencing 1920, of Canadian coal production, importation, consumption, and exports, based on anticipated rate of population increase, and continuation of the gradual increase in the per capita rate of coal consumption in Canada that had taken place every year up to 1920. The following comparative statement brings our the differences between the forecast and actual experience:

Jan 1, 1936

By K. S. Fraser, H. J. H. Pieterse

"A pressure oxidation plant to pretreat refractory sulphide ore at the Goldstrike plant in Nevada, was commissioned in early February 1990. The plant, with a nominal capacity of 1363 t/d, was commissioned over a one-week period and achieved design capacity and availability within ten weeks an unusually short period for a plant of this complexity.The pressure oxidation process is conducted under elevated temperature and pressure conditions, and in a corrosive environment. These conditions demand that the process and engineering design of the plant be carried out in a much more sophisticated and detailed manner than is normally required in a conventional gold plant.This paper provides an account of the process and engineering design of the Goldstrike pressure oxidation plant with special emphasis on the design of the vessels, slurry pumps, piping, valves, and control systems.BackgroundLocationThe Goldstrike property is located in Eureka County in northcentral Nevada on the Carlin geological trend. The mine is approximately 40 km northwest of the town of Carlin which is situated on Interstate Highway 80. The minesite is located 1700 m above sea level in the Tuscarora Mountains.Initial Goldstrike OperationsShallow, low-grade mineralization was discovered by diamond drilling in the Goldstrike area in the 1960s. A heap leach operation was established in the mid-I970s by the previous owners. The Post deposit was discovered in 1982. Gold production by mining and heap leaching reached I t/a (40 000 oz/a). American Barrick purchased the property in 1987 and started an aggressive program of deep drilling. This led to the discovery of the Betze and Deep Post deposits and established sufficient reserves to justify an initial 4100 t/d mill and a 5 500 000 t/a heap leach operation"

Jan 1, 1992

By Jack Craft

Local Environment Atmospheric conditions (or lack thereof) Drilling fluids are impractical Cuttings removal is a major concern Heat dissipation is a major concern Some tried-and-true mechanisms need air to function properly Gravity Low gravity means low downforce Microgravity means even less downforce Regolith Local dust may be highly abrasive Packaging for Spaceflight System mass is highly constrained The drill must fit within the spacecraft?s launch envelope Power is constrained

May 1, 2013

By Fathi Habashi

"Hydrochloric acid (HCl), although more expensive than sulfuric, find uses as a leaching agent in reactions involving iron oxide. The reason for this substitution was the discovery that oxyhydrolysis of ferrous chloride by which HCl can be recycled economically. This avoided the pollution of the environment by ferrous sulfate. It was found further that the rate of leaching of sulfides is faster when HCl is used as compared with sulfuric apparently due to the formation of aqueous chlorine. In case of refractory gold ores, HCl leaching under pressure avoids the use of cyanide solution since gold chloride is produced which can be recovered by standard methods. Hydrochloric acid find also uses in the leaching of scheelite and apatite but its use in leaching clay and anorthosite is questionable.INTRODUCTION Sulfuric acid is the cheapest acid and is used as a leaching agent in many hydrometallurgical processes. However, hydrochloric acid (HCl), although more expensive since it is prepared by reaction of sulfuric with sodium chloride, has replaced sulfuric acid in many reactions involving iron oxide. It replaced sulfuric acid for the first time in 1960s in pickling of steel because of pollution problems (Habashi, 2000). Ferrous chloride produced in pickling can be economically decomposed to ferric oxide and HCl according to:2FeCl2 + 2H2O + 1/2O2 ? Fe2O3 + 4HCl (1)which also shows that the acid can be regenerated but ferrous sulfate cannot be economically decomposed to recover sulfuric acid for recycle. Since then, HCl has been used in many leaching processes. Hydrochloric acid is a corrosive acid and is usually handled in rubber-lined equipment. REGENERATION OF HYDROCHLORIC ACID Regeneration of HCl is conducted in fluidized bed or in spray roaster Fluidized bed oxyhydrolysis In a fluidized bed, ferrous chloride solution is introduced onto a bed of hot ferric oxide where heating is provided by the hot fluidizing combustion gases (Figure 1). The solution is fed on top of the bed of oxides. The liquid feed wets the outer layer of the hot oxide particles and is quickly evaporated to form a layer of new solid oxide on top of the existing oxide, thereby producing dense homogeneous particles."

Jan 1, 2017

By D. C. Fuller

"CoaLiquid, Inc. (CLI) has been in the coal-oil-mixture (COM) business for over five years. The initial pilot processing facility was replaced by a 2000 barrel per day commercial production facility in August 1979. For over two years CLI has been expanding its efforts and conducting large-scale production and combustion demonstrations successfully in many locations across the United States. To facilitate the marketing effort, CLI has recently constructed a special trailer containing all equipment needed for a temporary COM retrofit.CoaLiquid has conducted commercial-scale combustion demonstrations in the following types of combustion units: kilns, calciners, industrial boilers, blast furnaces and driers.IntroductionCoaLiquid, Inc. officially dedicated its plant on August 31, 1979, at a ceremony presided over by the then Governor of Kentucky, The Honorable Julian Carroll. The dedication marked the culmination of over three years of research and development work and marked the beginning of a new era of coal-oil-mixtures as a commercial commodity in the marketplace. As the first such plant in the United States, it set the tone for construction to follow.CLI was originally owned and managed by a group of entrepreneurs from Kentucky who had developed the process and constructed the plant on purely private investment and conventional financing. Beginning in late 1976, with a pilot-scale operation, also located in Shelbyville, Kentucky (near Louisville), CLI began producing a stable mixture of 50070 coal, 30% to 40% oil and 10% to 20% water by weight. The technology employed was developed by Eric C. Cottell of Long Island, New York and is covered by U.S. Letters Patent No. 3,941,552. Since the pilot plant operation, CoaLiquid has made many refinements to its process and in fact has added new technology to its portfolio of patents and patents pending. Further refinements to the product now produce a stable mixture of 50% coal, 40% No.6 fuel oil and 10% water by weight."

Jan 1, 1985

"In response to mine head grades declining and orebodies becoming more complex, Glencore Technology has developed an alternative method for recovering economic minerals once leached into solution, rather than relying on conventional flowsheet options. The method involves the precipitation and separation of base metals from solution with limestone or lime. The final grade of these precipitate is not usually high enough to attract favourable terms of sale due to dilution from gypsum and sulphate salts. A set of operating conditions have been developed to allow the separation of the base metal precipitate from gypsum by exploiting the difference in particle size. A high-grade oxide product can be easily separated from the gypsum stream at very low cost. This process was originally developed by Glencore for zinc and copper systems. This paper reports on the successful application to nickel and cobalt, and this process has significant advantages over the incumbent precipitation process utilising magnesia.INTRODUCTION During evaluation of transitional and oxide zinc ore deposits during the 1990’s, Noranda Inc. (now Glencore) developed a sulphate based ore leach process to extract zinc into solution. For flowsheet development, conventional schemes dictated that once the zinc was dissolved in an acidified solution it was recovered by means of purification or solvent extraction followed by electrowinning and casting to produce zinc ingots. The deposits Noranda evaluated were high grade but had a relatively short mine life (10 years) and economic analysis showed that the projects couldn’t sustain the investment of a full zinc refinery. Compounding this problem was the lack of power supply infrastructure and the high power cost in the region. Noranda then evaluated alternative means of recovering zinc from solution. Laboratory testwork showed that a high-grade zinc precipitate (+50 wt% Zn) could be produced as an oxide, carbonate or sulphide by contacting acidified zinc sulphate solution with a number of reagents including soda ash, sodium hydroxide, and sodium hydrogen sulphide. Economic evaluation showed that the cost of the reagents are prohibitive, especially when the final product is still a metal intermediate (ZnO, ZnCO3 or ZnS). Noranda then continued to focus on fine zinc oxide precipitation for supply into the automotive tyre industry as this product would attract favourable terms of sale as a premium on Special High Grade (SHG) zinc."

Jan 1, 2017

By R. E. Whitehead

"Abstract - Alkali-alumina and MgO-alumina plots are an effective instrument for displaying chemical and mineralogical compositions of altered and unaltered rhyolites and rhyodacites. They reveal that most supposedly unaltered rhyolites, apart from those of Cenozoic age, have undergone losses in Na2O and gains in K2O. The extreme loss of Na2O from highly altered rhyolites immediately adjacent to VMS deposits is strikingly illustrated by alkali-alumina plots. MgO/Al2O3 vs. K2O/Al2O3 diagrams display a strong negative correlation between MgO and K2O that results from the conversion of sericite to chlorite. A similar negative correlation between MgO and whole-rock d18O is apparent on plots of these two parameters. Alkali-alumina plots underscore problems in selecting appropriate precursor compositions required for mass-balance calculations. Molar ratio plots are a viable alternative to such calculations. Sommaire -Les diagrammes alcali-alumine et MgO-alumine constituent un instrument efficace pour la représentation des compositions chimiques et minéralogiques des rhyolites et rhyodacites altérées et fraîches.Ces diagrammes révèlent qu’à l'exception de celles d’âge Cénozoïque, la plupart des rhyolites qualifiées de fraîches ont subi une perte de Na2O et un gain de K2O. L’intense perte en Na2O que l’on note dans les rhyolites fortement altérées associées aux gîtes de type SMV est particulièrement bien mise en évidence par le diagramme alcali-alumine. Le diagramme MgO/Al2O3 vs. K2O/Al2O3 montre une forte corrélation inverse entre le MgO et le K2O due à la conversion de la séricite en chlorite. Une corrélation inverse analogue entre le MgO et le d18O de la roche totale s’observe sur un graphe comparant ces deux paramètres. L’usage du diagramme alcali-alumine fait ressortir combien il peut être difficile de choisir un précurseur de composition appropriée pour des calculs de balance de masse. Les diagrammes de rapport molaire constituent une alternative à de tels calculs."

Jan 1, 2006

By C. E. Rodgers

WHEN the writer was engaged early last year by Canadian Comstock and its subsidiary, the Metropolitan Electric Company, to act as Consulting Mining Engineer in connection with the layout and equipment of the new ore-dressing laboratories at Laval University, Quebec, the metallurgical laboratory section of the School of Mines building was completely erected, including plastered walls, partitions, etc., and finished concrete floors. At that time, however, no equipment had been ordered, except three Dominion ball-mills and two Bell screening machines. ADVANCED OR CONTINUOUS LABORATORIES The continuous laboratory section of the Department occupies the basement and three floors of the building, with an approximate floor area of 9,000 square feet. Because of limitations imposed by the design of the building (height and arrangement of rooms, strength and design of floors, etc.), modifications of layout from what otherwise seemed most desirable were, of necessity, made. These included: (a) Omission of automatic sampling of the dry ore. (b) Complete elimination of inclined belt-conveyors through floors. (c) Exclusion of bucket elevators for either dry or wet ore transfer. (d) As a substitute for grill-covered drains and floor sumps, drainage from sections or from individual pieces of equipment was piped to a disposal system in the basement. (e) Substitution in several instances of fabricated steel in place of the usual concrete foundations for machinery. (f) Reducing floor cutting and area of such opening to a minimum. Ore storage and chute capacity above the basement level was also minimized to reduce total weight.

Jan 1, 1941

By Knut F. Garshol

Quality and durability of sprayed concrete depends on the concrete mix design, the type and use of accelerator and all the aspects of the placement onto the rock surface in the underground working. A large number of influence factors are involved and they must be managed for a successful and durable permanent sprayed concrete structure to be produced. The paper discusses some of the central issues, including how to view the long-term effects of chemical admixtures and accelerators in wetmix sprayed concrete. Permanent lining sprayed concrete for rock support is increasingly being used today and the durability can be equally achieved as for any other concrete.

May 1, 2003

By Edward S. Bell, Frank Angebrandt

"Nuclear reactors must have very large heat outputs to compete with conventional sources and the only feasible applications are in the production of electric power or large quantities of process steam. This paper considers alternative fuels for electric power generation in Canada. In a publicly owned utility, nuclear stations are economic for base-load generation for unit sizes of 500 mega• watts or larger where competitive fossil fuel costs are higher than about 30 cents per million Btu. In British Columbia, Alberta and Saskatchewan, fossil fuels will continue to be in adequate supply at costs lower than 30 cents per million Btu and thus, except for the special case of Vancouver Island, power generation in Western Canada will continue to be the hydraulic and conventional thermal type. In Eastern Canada, fossil fuel prices are likely to be higher than 30 cents per million Btu and most utilities will be able to install units of 500 mw or larger, so that nuclear power plants will provide much of the base-load generation required. Base-load generation comprises about two-thirds of the energy generated by power utilities. By 1990, the total annual electrical energy load will be over 600 billion kwh, with two-thirds of this load in Eastern Canada. Allowing for additional hydraulic resources which may be developed in Quebec, British Columbia and Manitoba, hydraulic generation is forecast to provide a little more than a third of this electrical energy, nuclear generation a third and fossil-fuelled generation about a quarter."

Jan 1, 1969

By R. Amata

"The Gakara Rare Earth deposit in Burundi (East Africa) is unique for its high grade (e.g., 54.3% TREO on average) and low uranium and thorium levels. The majority of the light rare earth (RE) elements in material from Gakara are contained within the familiar RE minerals bastnaesite and monazite. Extensive metallurgical test work was conducted by SGS Minerals Services on mineral samples collected from the Gakara deposit. Various whole ore hydrometallurgical processing routes were examined in a scoping level test program. Preliminary beneficiation testing was also conducted, though it was determined that only marginal upgrading would be achieved with significant RE losses. Thus a hydrometallurgical process on whole ore was developed to minimize the overall process complexity and achieve maximum RE recovery. Results from the test work will be presented, along with the selected base case flowsheet involving agitated atmospheric sulphation of the RE minerals, RE double sulphate precipitation, caustic conversion, redissolution, and carbonate precipitation. Following the base case flowsheet, a purified cerium free mixed RE carbonate with low levels of radioactive elements was produced.INTRODUCTIONRainbow Rare Earths Limited (Rainbow) is a mining company engaged in the exploration and development of the Gakara rare earth deposit in Burundi; Figure 1 shows the project location. The project is located in the Bujumbura Province and 45 km from the Burundi capital of Bujumbura. Notable for its exceedingly high in-situ grade – 54.3% on average total rare earth oxide (TREO), low uranium and thorium levels and familiar rare earth minerals, bastnaesite and monazite – Gakara is the world’s richest rare earth deposit. The project, a previously operating mine from 1948–1978, has a significant mineral inventory base, a long life of mine, well understood mineralogy, and robust economics. Rainbow is focused on bringing Gakara into production in the near term, ramping up to produce 5,000 t/y of a 54%+ TREO concentrate."

Jan 1, 2016

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