Search Documents

By G. Halverson, K. Blower

"Giant Yellowknife Mines Limited (Giant) has been producing gold since 1948. Located at Yellowknife, Northwest Territories, Canada, see Figure 1, the mine processes approximately 1,200 short tons per day of 0.23 ounce gold per ton of ore.The majority of the gold in the ore is sub-microscopic and associated within the mineral arsenopyrite. This association complicates the extraction method since straight cyanidation will only recover 30% of the gold. The operations at Giant involve four essential steps, with an overall recovery of 87%. The steps shown in Figure 2 are crushing and grinding, flotation, roasting and cyanidation. These processes result in a number of effluent waste streams characterized in Table 1. These streams are combined and sent to a tailings storage pond for subsequent treatment prior to discharge to the environment.Giant is located just north of the 62nd parallel where winter temperatures drop to -40°C for extended periods. This entails storing effluent in dams over the seven month winter period for treatment during the relatively short summer season.The treatment method currently employed at Giant is an ""alkaline chlorination-arsenic precipitation-flocculation"" process. The pond water is subjected to three phases of treatment prior to being discharged to the environment as shown in Figure 3."

Jan 1, 1987

By C. L. Monroe

It has been the custom in recent years to look upon Atlin as a worked-out placer camp. This is a conception, however, which is far from the real situation. The placer-gold deposits of Atlin are today, after thirty-one years of continuous working, a field well worth the attention of the mining world. It is true that the shallow diggings (the 'easy money') have been practically cleaned out, but although there have been perhaps ten millions, or more, in gold already taken from the district, there are still many more millions left in the creek beds . A conservative estimate of the gold still remaining in one creek alone, Spruce creek, for a long time known as the 'prospector's meal ticket', would place the amount at anywhere from fifteen to twenty million .dollars, and there are a number of other creeks that have never been thoroughly worked, and some only partially prospected. That the true situation is beginning to be recognized by those who are on the lookout for a profitable field for investment, is born out by the fact that, within the last few years, New York capital directed by Mr. Charles V. Bob, who is also responsible for the opening up of the Engineer mine, has installed on Pine creek, where the first discovery of gold in the district was made, one of the largest hydraulic mining plants on the continent, utilizing six miles of the old hydraulic ditch of the Discovery Mining and Power Company, and over two miles of pipe line. On Boulder creek, where already two millions have been taken out, the Consolidated Mining and Smelting Company are on their third year of development work in opening up the unworked ground, while on Otter creek a newly organized French company have started a plan of development which will involve an expenditure in the neighbourhood of $200,000, and two or three years' work, before they can hope to find gold in paying quantities. It is probably safe to prophesy that placer gold will be produced in the Atlin district for the next fifty years

Jan 1, 1929

By H. T. Kennedy, D. L. Flock

"The project described in this pa-per was undertaken to provide a more thorough understanding of the effect of contamination by drilling fluids on the electrical properties of porous systems. The basic work per-formed was filtration tests on both consolidated and unconsolidated sands and the determination of their resistivity profiles with the aid of screen-type electrodes spaced at convenient intervals along the core.Four drilling fluids were selected, ranging in resistivity from 447.0 ohm-cm. to •5.76 ohm-cm. The permeability of three unconsolidated and four consolidated cores, on which resistivity measurements were made, varied from 1,257 md. to 4,560 md. Five additional cores with permeabilities as low as 49 md. were tested to investigate the effect of permeability on the depth of invasion of drilling fluids.The effect of drilling fluid invasion on resistivity profiles was determined on cores containing brine only, and on those containing 80 to 90 per cent oil and 20 to 10 per cent brine. The study included measurements of (a) clay content of different sections of the core, (b) saturation of the invaded fluids and oil in different parts of the core, and ( c) changes in resistivity as a result of gravitational re-distribution of fluids and diffusion of electrolytes.The data showed that the resistivity of an invaded core is, as was expected, controlled by the resistivity of the filtrate, the resistivity of residual core water, the resistivity of the clay particles, and the amount and distribution of the filtrate, clays, residual oil, and brine. In most cases there was a significant increase in resistivity owing to the presence of clay solids which had invaded the core. The change in resistivity, as a result of the diffusion of salts, was substantial after a period of five hours. There is evidence in some cases that the residual oil and core water saturations of the unconsolidated cores, after substantial invasion, are very low, indicating almost complete displacement by invading fluid."

Jan 1, 1959

By Daniel Hodouin, Claude Bazin, René del Villar

"A traditional linkage has long been established at Laval University's Department of Mining & Metallurgy between the Mineral Process (MP) and the Mining Exploitation (Min) on one hand, and between the Extractive Metallurgy (EM) and the Materials Engineering (Mat) on the other. This academic separation of Mineral Processing from Extractive Metallurgy at the educational level has become increasingly at odds with today's industrial practice in which both disciplines are not only complementary but also often intertwined. For instance, in gold ore processing, comminution, flotation, and gravity separation units are interfaced with atmospheric or pressure leaching modules and with carbon adsorption and electrowinning units. The new copper plants in South America combine comminution and flotation circuits with heap leaching, solvent extraction and electrowinning processes.In order to reflect this new industrial reality and to harmonise the options offered in both its engineering programs, the Department of Mining and Metallurgy of Laval University has introduced major changes in its curriculum in 1996. These changes reflect also the recognition that the somewhat secondary status given so far to Mineral Processing and to Extractive Metallurgy within their ""mother"" programs, Mining/Mineral Engineering and Materials metallurgical Engineering respectively, was in sharp contrast with their actual significance for the Canadian economy. Leading industrial voices have raised similar concerns and the Canadian Engineering Accreditation Board has also addressed this problem in its latest program evaluation.The changes implemented at Laval aimed at a) better representing MP and EM within the two undergraduate programs; b) training top-level versatile and multidisciplinary engineers, fluent in all aspects of MP and EM, irrespectively of which of the two ((mother)) programs they had chosen and capable of meeting today's industrial requirements; c) training students in process analysis, optimisation and automatic control using state-of-the-art software, and d) taking into account the co-operative nature of both undergraduate programs.Results are very encouraging in terms of student enrolment and industrial response. However, some concern is expressed on the sustainability of the renewed curriculum considering the drastic budget restrictions in effect at Laval as in most other Canadian universities."

Jan 1, 1999

By Glenn Clarke, Ben Holloway, Barry Lumsden

"BHP-Billiton’s Cannington mine in Northwest Queensland produces a silver-rich lead concentrate and a zinc concentrate. The plant has the capacity to treat 3.1 mta and for the year to June 2006 mean feed grade was 10.3% Pb, 461 g/t Ag and 3.7% Zn. Recovery losses of lead and silver are primarily in the fine fractions. In 2001, the plant was modified when it was determined that splitting the lead feed into two size fractions, and floating the two fractions separately increased fine lead and silver recovery. The fine lead fraction (called the split float) is 80% <16µm and about a quarter of the lead and silver is in the finest fractions. In 2006 to further improve lead and silver recovery a statistical plant trial of magnetic aggregation conditioning of the split float feed was undertaken. While pure galena is diamagnetic the Cannington galena contains iron within the galena mineral resulting in the galena having a paramagnetic, magnetic susceptibility. The trial demonstrated to greater than 98% statistical significance an increase in lead recovery, and to 99% statistical significance an increase in silver recovery, and to greater than 97% significance an increase in the lead in concentrate in the split float circuit. These economic recovery benefits with magnetic aggregation of the split float feed, has led to the incorporation of this technology in the plant.INTRODUCTIONThe BHP-Billiton owned Cannington silver, lead and zinc mine is located in the Australian state of Queensland about 800 kilometres west of the coastal city of Townsville. This is a pastoral area characterised by large cattle farms, low population density and very little infrastructure. The area has two seasons, a wet, hot summer and a dry, mild winter. Because of its isolation and lack of infrastructure the mine has always operated on a fly in fly out basis.Geological drilling defined the resource as 43.8 million tonnes grading 11.6% lead, 4.4% zinc and 538 ppm silver (Walters and Bailey, 1998). At times during its history Cannington has held the crown as the single largest lead and silver mine in the world (Torrisi and Smith 2003). Another unique characteristic of the operation’s history is the rapid progress from discovery to operation. The first drill to intersect the ore body was in 1990 and the mine and plant was commissioned in 1997."

Jan 1, 2008

By P. H. Oliver

"The current theory of how explosives fracture rock offers no explanation for the improvements in fragmentation and the reduction of fly rock and back break which occurs when an adequate inter-row delay time is used. Nor does it explain why fragmentation improves with rectangular drill patterns where the hole spacing may be as much as four times the hole burden.A new theory of rock fragmentation is proposed which builds on the existing theory. It offers rational explanations for the many blast effects which the current theory does not address and the need for adequate timing delays between rows. It improves on the design of inter-row delay timing by defining the length of free-blasted face needed in front of a hole *Retired from Inco Ltd., Sudbury, Ontario when selecting the delay element which will provide an adequate inter-row delay time."

Jan 1, 2003

By P. H. Oliver

The current theory of how explosives fracture rock offers no explanation for the improvements in fragmentation and the reduction of fly rock and back break which occurs when an adequate inter-row delay time is used. Nor does it explain why fragmentation improves with rectangular drill patterns where the hole spacing may be as much as four times the hole burden. A new theory of rock fragmentation is proposed which builds on the existing theory. It offers rational explanations for the many blast effects which the current theory does not address and the need for adequate timing delays between rows. It improves on the design of inter-row delay timing by defining the length of free-blasted face needed in front of a hole when selecting the delay element which will provide an adequate inter-row delay time.

May 1, 2003

By K. S. Kalenchuk

Massive landslides display complex deformation processes. For instance, slope movements of the Downie Slide, monitored using borehole inclinometers, extensometers, and survey monuments, show considerable spatial and temporal inconsistencies in the displacement rates. This study assesses the influence that inferred shear surface geometry, as a key factor contributing to variable slope movements, has on resolving spatially discriminated slope deformations in three-dimensions. Borehole data defines the shear surface location at discrete points within the slide and therefore, the shear surface geometry for the extent of the slide must be largely inferred. A series of three-dimensional numerical simulations have been run to assess the effect of different interpretations of the shear surface geometry. This investigation illustrates the importance of rigorous geospatial definition of slip surface geometry and the value of three dimensional modelling.

May 1, 2009

By Derek J. Cyr

Climate has an immense impact on the properties of Athabasca oil sands and the ease or difficulty with which it is excavated and extracted. During the winter months, exposed oil sands surfaces freeze. When hydraulic and electric shovels used in the various operations in the Fort McMurray area excavate the benches, large frozen lumps are created. These lumps are either destined for a lump dump where increased costs are incurred due to rehandle, or they are sent to the primary crushers where they can cause significant downtimes by jamming the crusher. The crusher down time can sometimes be in the order of hours of lost production. Studies on data from two consecutive winters at Syncrude Canada?s North Mine show a high correlation between climate and the generation of frozen oil sands lumps. Temperature, ground cover, traffic, bench exposure time, oil sands grade and moisture content all contribute to this problem. A 1D frost penetration model was used to predict the depth of frost expected in oil sands and the corresponding likelihood of frozen oil sands lumps. To combat the challenge of frozen lump generation, a number of proactive and reactive measures can be taken: artificial snow, shallow ponds, scheduling, blasting or ripping.

May 1, 2004

By P. O. Parfitt

The Critical Path Method has proved its usefulness at Mcintyre Porcupine Mines Ltd. This paper illustrates the techniques of network construction and analysis, and the application of the method at the Mcintyre copper mine to various projects in the gold mine. C.P.M.'s use in a mill maintenance project is also discussed.

Jan 1, 1966

By G. C. McKerrow

"Mr. G.C. McKerrow, Assistant Manager of Noranda Mines and formerly Smelter Superintendent attended the meeting to answer questions as to why smelters imposed penalties for too much zinc in a copper concentrate or too much copper in a zinc concentrate, etc.D.W. Bridges -Mattagami Lake MinesWhat limits do you set on zinc and lead in a copper concentrate?G.C. McKerrow - At Noranda, we allow 5% zinc free and charge 25 cents for every unit above that. For lead, it is 1% free and 25 cents per unit above that. Lead is a much more harmful impurity than zinc because it tends to recycle more in the smelter circuit and creates a greater health hazard in the plant.E. Thornton - Sullivan GroupWHat harm does fluorine do in the smelting process?G.C. McKerrow - Fluorine usually does not occur in harmful concentrations in non-ferrous smelters. Fluorides are present in exhaust gases in the aluminum and phosphate industries. If these fumes escape into the atmosphere, they may settle out on forage grasses in concentrations that are harmful to livestock.Thorton - Sullivan GroupI have asked this question other places and have been told that it is hard on brick linings and causes gold and silver to be lost up the stack.G.C. McKerrow - Almost any volatile constituent in a smelter charge will aid in carrying other metal values. To this extent it may be harmful.E. Thornton - Sullivan GroupMr. Tait mentioned before a smelter where they have a copper-tin ore and they pay for copper, tin, bismuth and silver but object strongly to indium in the concentrate. Why would this be?G.G. McKerrow - 1 can't see why indium would be a serious impurity. It does tend to concentrate in flu dusts and if you get enough of it you can recover it and sell it but I have never heard of anyone putting a penalty on it.Question - I once ran into a small copper mine in Peru that had cadmium in the copper concentrate but no zinc. The copper smelter charged a penalty for the cadmium. Why would this be?"

Jan 1, 1971

By Oliver B. Hopkins

"WE HAVE patterned our lives on the things we take from under the earth's surface. Our civilization is built upon the ore from which we obtain our metals and the fuels which power the world as we know it.Today I should like to discuss with you a newcomer to the ancient mining industry. This lusty infant of which I speak is just a century old - the oil industry.While one doesn't commonly think of oil men as delvers in the earth, It was by sinking a shaft that the first oil was obtained commercially in Canada. Men sank a shaft in a ‘gum bed' in southwestern Ontario's Lambton county, not far from Petroilia, and distilled from the gum a burning oil That was just a hundred years ago. The gum was originally liquid petroleum which had seeped to the surface and lost most of its volatile components.Later, the miners dug down to •bed-rock and soon after they were not digging but were drilling wells, as they have been ever since. From the wells they obtained erode oil.What is crude oil? It is not an element like gold, silver or lead, •but a complex mixture of compounds. These compounds are made basically from two elements, carbon and hydrogen, and are called hydrocarbons (Figure 1).The remarkable ability of these. Two elements to combine in different ways gives crude oil its physical and chemical character. The lighter hydrocarbon compounds in it are gases, at normal temperature and pressure, and these are dissolved in the other, heavier compounds."

Jan 1, 1952

By Baki Özüm

Early evaluations of Pasquia Hills kerogen shale deposits by Geological Survey of Canada, Saskatchewan Geological Survey, Manitoba Energy and Mines and Sun Oil Company, using modified Fischer Assay, Rock-Eval and other techniques, estimated recoverable reserves of about 2.6x109 barrels of oil in areas favorable for strip-mining; each metric ton of ore was determined to yield about 30 L to 50 L of shale oil remarkably high in aromatic compounds. Western Petrochemical Corp. (WPC) is holding two Oil Shale Exploration Permits covering about 76,635 hectares in the Pasquia Hills Region of eastern Saskatchewan and conducting a 15-corehole drilling program to determine stratigraphic correlation on both first and second white specks kerogen shale. In this program, correlation will be established between oil yield and oil quality, using different retort techniques, including modified Fischer Assay, steam retort and Rock-Eval. Results will lead to further resource evaluation and to a preliminary engineering design for a shale processing plant, including selection of retort process, upgrading of shale oil to petrochemical feedstock, hydrogen management, energy balance and evaluation of environmental impact.

May 1, 2002

By W. R. Lindsay

Considerable attention has of late been given to the blasting of large amounts of ore in one operation, on account of the saving in labour and explosives and consequent low cost per ton, and also on account of the additional safety to employees. The blast here described, at the Hidden Creek mine. at Anyox, B.C., is not necessarily unique either in size or methods employed, but some interesting p10blems were encountered and the solutions of these may be of interest to others engaged in similar work. The ore consisted mainly of old scope-bottoms and sill pillars, although there also were some braces and parts of vertical pillars included. Some of the stope-bottoms were overlain by caved waste, and one of the problems was to break them in such a manner that the maximum amount of ore could be recovered without serious dilution with waste. The ore blocks, designated as the 385 silt and the 7 A-103 blocks, were under preparation for blasting for over a year, as conditions permitted. This work consisted in drilling long machine drill holes, varying in length from 14 to 20 feet. These holes were drilled with the Numa detachable bit, made locally, starting at 2~-inch diameter and bottoming at 2 inches for the longest length. The long hole drilling was used in the thinner sections of the area. For the stronger, thicker portions, powder drifts (3 ft. by 4 ft. in section) were driven for the powder charges. Reference to the plan and sections (Figures 2 co 8 inclusive) show the relative location of these, as well as the long drilling. The amount of explosives used in the powder drift charges averaged 0.25 pounds per ton of estimated burden, varying from 0.2 to 0.3 pounds per ton.

Jan 1, 1934

By Pierre Gaucher

It is possible to selectively mine an orebody by combining the use of the SSW probe with any bulk mining methods as well as narrow vein exploitations. In other words, thanks to the use of the SSW probe, mining operators will be able to reduce and control dilution that is generally associated to every mining operation. Already, quick and substantial savings have been obtained. Falconbridge mines have demonstrated in Sudbury and Raglan operations, that the SSW probe can log nickel, copper and iron sulphides in blast holes. They have raised the grade and reduced dilution by outlining the limits of the ore zones before selectively loading explosives in the blast holes. By lowering the probe in a blast hole, a profile of the ore content is instantly measured and recorded. Logging cored diamond drill holes at the mine have demonstrated that the ore content (nickel, copper, cobalt, PGM) as assayed is proportional to the intensity of the probe?s electromagnetic response (EM), probably because the nickel / pyrrhotite ratio is uniform within a given orebody. The probe also measures the intrinsic conductivity of the sulphides and the percentage of magnetite. All probe readings are displayed and automatically stored at a 10-cm interval within the same reading unit. A 30-meter blast hole takes less than 2 minutes to survey. The whole instrument is light (12 kg) and very simple to use. One operator can carry the SSW system and survey either down or up-holes. The probe works from ?40°C to +50°C. Plotting the measurements of the SSW probe in blast holes (2-3-4-6-10 inches in diameter) before blasting allows to determine the exact shape of the orebody within the waste rock and uneconomic low-grade ore. Thus, only the portion of the holes that contains ore is blasted. The dilution is then much reduced and, by leaving the waste and low-grade ore in place, the mine saves on transportation, blasting, crushing, backfilling, milling, etc. Thousands of dollars are thus saved. Some savings may also be achieved during the development of stopes by guiding development drifts and by replacing diamond drilling by percussion drilling. In some circumstances, when the probe shows that some of the rich ore was not drilled-off, additional blast holes will allow to recover pockets of rich ore that otherwise would have been abandoned in the walls of a stope.

Oct 1, 2001

By Neil McMillan

"By any measure of common practice, Claude Resources' Seabee Gold Mine in Northern Saskatchewan should not now be operating. Not because reserves dwindled, or grade dropped or prices weakened or technical problems arose, but because a host of unimaginable other problems beset the project, any one of which would normally have led to the mine's failure.The success of the Seabee Mine, and it is extremely successful, is a story of the vision and blunt determination of two men. Neither is remarkable in his own right but each possesses the characteristics which were necessary to forge a highly productive and profitable narrow-vein mine in the midst of the most bizarre and unpredictable events which likely have ever beset a mine start-up in Canadian history.Together, Bill MacNeill, a Saskatchewan born, former bush pilot and Ray Gagnon, a big hearted, hard-fisted, miner with 44 years of experience in Canada's underground, built the Seabee Mine.They didn't accomplish this with brilliant geology, outstanding engineering or nimble corporate manouvering but rather a stubbornness and raw common sense which likely are all too often, ingredients missing in failed projects.The Seabee Mine is 100% owned by Claude Resources, a Saskatoon based company taken over by Bill MacNeill, its current chairman, in 1982. The company is listed on the TSE and produces 1200 barrels of oil per day and about 60,000 oz of gold per year. The company has a strong balance sheet, is very profitable and has 18 million shares outstanding.The Seabee property in Northern Saskatchewan started out like many other gold exploration properties in Canada.It was discovered in the l 940's by what is now Cominco, and, while highly regarded by that company the property sat largely dormant until acquired by Claude Resources in 1985.Claude did what most junior exploration companies would do and went looking for a company with a depth of expertise to joint venture the property.That company was Placer Development who could earn a 55% interest in the Seabee by delivering a bankable feasibility study on the Project by July 1988 and providing financing to production.Placer Development was an excellent company and spent over $8 million dollars on the Seabee over a 3 year period. Unfortunately for Claude Resources, Placer Development merged with Dorne Mines in 1987 and the new merged company, Placer Dome, established a minimum production threshold greater than the 50,000 oz per year which the Seabee appeared capable of supporting at that time. Placer Dome's request for an indefinite extension of the joint venture agreement to allow it to drill off a larger ore body was rejected by Claude Resources and the Seabee Property was returned to Claude in 1988."

Jan 1, 1998

By S. Yalcin, S. Chang, M. Oliazadeh

"Present day ferrochrome demand is on the rise, as more steel products require this material as an alloying element. It is projected that the stainless steel demands will grow by about 6% per year to 2020; as such, the supply and demand for ferrochrome appears promising. Chromite is the only economical source of chromium, which is commonly upgraded by gravity techniques and used to produce ferrochrome. The gravity separation methods are not able to treat particles finer than 0.1 mm efficiently. Therefore, in processing chromite ore, a large quantity of fine tailings; some 25% of the mineral values have been reported as lost in slimes during processing. The chromite content of these tailings is typically 10-20% Cr2O3 and accumulates into a large stockpile/pond. A chromite concentrator project in Canada, considers a cut-off grade of 20% Cr2O3. This indicates further processing might be required to recover chromite from low-grade stockpile when the high-grade deposits are depleted. Low-grade ores normally indicates disseminated chromite ores with low liberation and consequently fine comminution. This paper reviews the techniques for treating chromite from fine material and provides some examples of successful operations in fine chromite recovery. Beneficiation techniques for fine particles include gravity separation, magnetic separation, and flotation. Several case studies are presented here that used one of the aforementioned methods or a combination of them.INTRODUCTIONChromium is one of the essential element and important material for production of ferrochrome alloys and special steel. Chromium occurs as chromium spinel, a complex mineral with chemical composition of (Fe, Mg) O (Cr, Al, Fe)2 . Chromite ore is exclusively found in ultramafic igneous rocks. Major associated gangue minerals are talc, quartz, serpentine and iron oxides.Chromite is a heavy mineral, with a specific gravity in the range of 4-5, relative to associated gangue minerals in a chromite ore, which makes gravity concentration a suitable process. This is generally true for coarse particles, ranging from 1 mm to 100 mm. Typically, the ore is prepared by crushing (and grinding if necessary) to a suitable size and the material is sized for the appropriate beneficiation techniques. It is common to use heavy medium separation (e.g. dense media drums, dense media cyclones, or Dyna Whirlpool) to treat coarse size and intermediate size particles (1 – 100 mm). Intermediate and fine particles (20 – 0.1 mm) could be treated by jigs. Spirals, shaking table, sluices, and Reichert cones can upgrade fine particles. Figure 1 shows a typical chromite beneficiation process flowsheet. As can be seen, it consists of three major sections: feed preparation (crushing, screening), de-sliming, and concentration. Beneficiation recoveries range from 80 to 85%, although the ratio of upgrading is only 2 to 3."

Jan 1, 2013

By R A. Stevenson

The purpose of this paper is to outline a recent development in ground fault protection. The paper deals with the A problems of both grounded and ungrounded systems, with regard to hazards to personnel and equipment, and shows that the increased sensitivity and speed of operation of this new detector results in increased safety to personnel and reduced stresses on equipment, and permits the detection of leakage currents before they become serious faults. The detector can be applied to all distribution systems, either A.C. or D.C., up to 15 kv., and the detector itself can be tested at regular intervals without interrupting line circuits. T HERE is always controversy among engineers as to whether distribution systems should be grounded or ungrounded. There are many experi-enced engineers on both sides of this controversy, and each have valid reasons for their choice

Jan 1, 1964

By Kevan J. R. Ford, Chris A. Fleming, Robert D. Henderson

"Kinross Gold Corporation’s Maricunga mine in Chile presents an ideal opportunity to apply the SART process to a heap leach operation. Given increasing levels of cyanide complexed copper in current pregnant solutions from Maricunga heaps (over 300 ppm Cu), there is a need to reduce these levels and decrease cyanide consumption and cost. Additionally, a means of disposing of this copper is required, preferably as a saleable product. The well published SART process applied to gold-copper cyanide solutions was selected as it allows rapid precipitation of cyanide soluble copper as a relatively pure copper sulphide. The process also allows effective recovery and recycle of cyanide back to the heap leach operation.This paper reviews the SART process chemistry and presents a summary of SART bench-scale and pilot plant testwork completed by Kinross. Key design parameters and engineering aspects of the proposed plant at Maricunga are discussed. SART plant operating costs and net revenue analysis are included and illustrate the compelling economics of installing a SART process plant. INTRODUCTIONMaricunga OperationCompañia Minera Maricunga (CMM), fully owned by Kinross Gold Corporation, operates the Maricunga mine (formerly Refugio) which is located 120 km due east of the city of Copiapó at an elevation of 4,200m above sea level in the Andes mountains of northern Chile. Figure 1 shows a map of the location of the Refugio mine relative to other gold and copper mines in the region."

Jan 1, 2008

By Norman O. Lotter

Drill core is preferred as the sample material for metallurgical and mineralogical characterisation and flowsheeting of an orebody. The question arises as to how to do this at the economic optimum, since geologists have several other strategic uses for their drill core. The limiting factors are the cost of extra drilling for the metallurgical testwork and the need to preserve the drill core record. In this study, the representative sampling of drill core at an economic optimum for metallurgical testing is addressed. This phase of the drill core work is preceded by earlier drill core characterisation - for which other appropriate sampling protocols are used - that has provisionally categorised the orebody into geometallurgical units. In stratified sampling of drill core, use is made of a version of the stratified approach to compound distributions proposed by Cochran in 1946. Use is made of Gy’s 50-piece minimum sample mass model to estimate minimum requisite sample mass. In the case where sampling and testwork are required on a Lifeof- Mine blend of a given ore deposit, whereby defined ore types or geometallurgical units are present, the sample mass requirement is significantly reduced by working from drill-core at the geometallurgical unit level. A case study using Raglan drill core is discussed. Using nickel as an indicator paymetal, and sampling at a fundamental variance level of 8%, the minimum sample masses for disseminated sulphides, net-textured sulphides, and massive sulphides are 3.80, 7.37 and 4.39 kg respectively. When the same drill-core is sampled as a Life-of-Mine mixture without knowledge of the geometallurgical units, the minimum sample mass increases to 84.28 kg. It is thus possible to assemble a representative Life-of-Mine sample of drill-core more economically, at the same time validating its representativity. Equivalent calculations for copper, platinum and palladium are discussed, with outcomes consistent with this finding. When all four paymetals are considered, one selects the largest minimum mass out of all four cases. This results in minimum sample masses of 11.67, 74.90 and 175.16 kg for disseminated sulphides, net-textured sulphides and massive sulphides respectively. The simulated Life-of- Mine blend would require a minimum sample mass of 377.33 kg to cover all four paymetals.

Jan 1, 2010