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By C. S. R. Rondestvedt

In February 2010, Teck?s newest Concentrator at Mina Carmen de Andacollo (CDA), Andacollo, Chile was commissioned. The Concentrator is a single line configuration, comprising of one 36 ft diameter x 20 ft long SAG mill driven by an 18,000 hp gearless drive. The SAG mill feeds two ball mills each 25 ft in diameter x 40.5 ft long, each driven by a total of 19,000 hp through dual pinion drives. A series of four phases will be reviewed from operational readiness, mechanical completion, commissioning, and ramp-up. Also, now after 6 months of operation, this paper will review the significant steps taken during ramp-up enabling the announcement of commercial production, in October 2010.

Jan 1, 2012

By L. Torres, C. S. R. Rondestvedt, M. Bustos

In February 2010, Teck’s newest Concentrator at Mina Carmen de Andacollo (CDA), Andacollo, Chile was commissioned. The Concentrator is a single line configuration, comprising of one 36 ft diameter x 20 ft long SAG mill driven by an 18,000 hp gearless drive. The SAG mill feeds two ball mills each 25 ft in diameter x 40.5 ft long, each driven by a total of 19,000 hp through dual pinion drives. A series of four phases will be reviewed from operational readiness, mechanical completion, commissioning, and ramp-up. Also, now after 6 months of operation, this paper will review the significant steps taken during ramp-up enabling the announcement of commercial production, in October 2010.

Jan 1, 2012

By M. Yamine, R. J. Ring, D. J. Waters

"An experimental program has been carried out by the Australian Atomic Energy Commission to compare the effectiveness of Caro's acid as an alternative oxidant to pyrolusite in the leaching of uranium ores from the Alligator Rivers region of northern Australia. Batch leaching tests on Ranger, Nabarlek, Koongarra and Jabiluka ores showed that uranium extraction was unaffected by choice of oxidant, but that Caro's acid reduced acid requirements by 15 - 25%. Lime requirements for neutralization of tailings liquors were reduced by 20 - 30%.The batch studies were extended to a four-stage continuous leaching circuit with a capacity of 400 gore h-I. Comparative leaching tests confirmed the reagent savings obtained in the batch tests. Following these encouraging laboratory results, lnterox Chemicals Pty Ltd carried out plant trials using Caro's acid. Reagent savings in the mill were similar to, or better than, those obtained in laboratory test work. The trials also established that Caro's acid has a number of operational advantages over pyrolusite.IntroductionUranium is most commonly extracted from its ores by leaching in sulphuric acid. Simple hexavalent uranium oxides and compounds are readily soluble but uranium in the tetravalent form is insoluble and must be oxidized for dissolution to occur. The most commonly used oxidants have been sodium chlorate and manganese dioxide. They act indirectly by maintaining iron as the ferric ion which oxidizes uranium by a surface electro- chemical reaction. An Fe3+ concentration of about 1 - 2 g L-I is usually considered adequate for the effective dissolution of uraninite(1)."

Jan 1, 1984

By F. Richards

"The property of the Cariboo Gold Quartz Mining Company; Limited; is in the Wells-Barkerville district of Cariboo mining division. It consists of a group of 106 Crown granted mineral claims and fractions; and extends for over 6 miles along what is termed the Barkerville gold belt. The main portal and mine camp are half a mile south of Wells; which lies at the northeast end of Jack of Clubs lake and is reached by a 55-mile motor road from Quesnel; the northern terminus of the Pacific Great Eastern railway.Gold-bearing quartz veins were discovered on the surface in various parts of the property by different prospectors as far back as 1877, but the work that led to the formation of the present company was performed by Al Sanders in the year 1926. Sanders dug trenches and drove small adits on quartz veins containing gold above what is now known as the Sanders zone. Very little underground work has been done beneath the earliest known discovery-the B.C. vein. The Cariboo Gold Quartz Mining Company was formed in the autumn of 1926. The total production of gold from its beginning in 1933 to the end of 1944 has been as follows:"

Jan 1, 1954

By D. Pearcey, S. T. Vessey, V. Hegde, J. Staples

"Pellet quality has taken on a new dimension during the last ten years. Quality in the seventies was generally defined as adherence to certain physical and chemical specifications. Today, the talk is in terms of how the business is managed, how customer's expectations can be exceeded, not only in product quality, but in service responsiveness.Coke breeze and flux additions, lower silica levels, and improved furnace control practices have all contributed to the improvement of pellet physical and metallurgical properties. Statistical process control has provided additional insight into the parameters that affect pellet quality.Increased customer contact and product quality surveys have heightened our awareness of customer needs and also provide direction for quality improvement test work. Current work is focussed on improving reducibility and understanding the relationship between tumble, fired compression and metallurgical properties.This paper will review the Iron Ore Company of Canada's efforts during the past decade and describe some of its initiatives for the future.IntroductionThe Carol Pellet PlantThe Iron Ore Company of Canada's Carol Project is located in Labrador City in the southwestern portion of Newfoundland and Labrador , approximately 965 Ian northeast of Montreal. The project consists of mining facilities, beneficiation complex and a pellet plant, which began operations in 1962. The pellet plant consists of six Dravo-Lurgi straight grate machines, regrinding, filtering and balling facilities. The current capacity of the Carol pellet plant is approximately 10.5 million tonnes , while the concentrator has the capacity to produce about 18 million tonnes of concentrate.The orebody consists of specular hematite, magnetite and small quantities of limonite and goethite. The average grade of the orebody is approximately 39% iron."

Jan 1, 1991

By John A. Meech, Irene E. Cristoveanu

"The separation of hematite fines (100% - 38 um) from quartz fines (100% -75 um) was investigated using coarse hematite (-212 + 150 um) as a carrier in an oleic acid collector system. Oleic acid additions, per cent coarse additions, combined conditioning time and ferric chloride additions were examined.It was found that carrier flotation is a dominant mechanism for fine hematite recovery at oleic acid levels greater than 200 g/t and coarse additions of 10 per cent. Hetero-aggregation is favoured under conditions of lower levels of oleic acid in the presence of ferric chloride and at conditioning times greater than ten minutes.Ferric chloride acts as a depressant for pre-reagentized coarse hematite at oleic acid levels below 150 g/t. At concentration levels above 500 g/t, ferric chloride interferes significantly with the success of carrier flotation of fine hematite.The sensitivity of carrier flotation to changes in oleic acid addition, ratios of fine and coarse material, conditioning time and the presence of an inorganic electrolyte emphasizes that its application is only suitable when flotation conditions can be stabilized.IntroductionThe production of fine material is unavoidable during the comminution of iron ore . Due to the difficulty of recovering iron from this fine material by various gravity separation methods, flotation can often be a more attractive process producing high-grade material at high recovery. One variation of the flotation process, that can be useful for recovering ultra fine minerals (<10 um) , is known as carrier flotation. This process involves the utilizat ion of coarse particles ( > 150 p.m) which act as flocculation centres to which the fine hematite particles (10 - 40 u.m) become attached and are carried or "" piggy-backed"" into the froth phase."

Jan 1, 1985

By J. Satur

In copper mineral processing, pyrite coexisting with copper sulfide minerals like chalcopyrite is separated by flotation as tailings and its oxidation in tailing dams causes the formation of acid mine drainage. This paper proposes carriermicroencapsulation (CME) as a new method for suppressing pyrite flotability, as well as its oxidation. In this method, an organic carrier combined with Ti is used to form a thin Ti02 layer on pyrite, which gives a hydrophilic property and acts as a protective coating against oxidation. To form the coating, a ground pyrite sample was treated with Ti-catechol complex solution under various conditions. Bubble pick-up experiments and flotation experiments showed that the treatment of pyrite with Ticatechol complex changed the hydrophobic nature of pyrite into hydrophilic even in the presence of xanthate as a flotation collector. Oxidation testing of the CME-treated pyrite by 0.02 kmol m-3 HN03 showed that Fe release was suppressed by the CME treatment with respect to the control. This is assumed to be due to the formation of Ti02 coating on the pyrite surface. The effect of CME treatment on chalcopyrite wettability is also discussed.

Jan 1, 2007

By Magella Pelletier

"IntroductionDepuis une vingtaine d&apos;année, les nombreux travaux de géochimie effectués par l&apos;industrie privée et les milieux gouvemementaux ont permis:• de découvrir de nombreuses zones minéralisées a valeur économique;• d&apos;identifier et de vérifier certains patrons de dispersion géochimique au-dessu s de secteurs minéralises déjà connus;• de favoriser le développernent des techniques analytiques;• de forcer le développement d&apos;une mise en carte des résultats d&apos;analyse, qui soit plus adéquat afin de permettre une meilleure interprétation géochimique.L&apos;une de ces cartes géochimiques qui permet le mieux de mettre en valeur les données analytiques et qui fut instaurée au debut des années 80, est la carte d&apos;interprétation géochimique par pondération.Cette carte numérique semi-quantitative, qui est construite à partir des données de base et de l&apos;importance des éléments indicateurs pour une substance donnée, permet d&apos;identifier et de définir des zones possédants de fortes probabilités pour la recherché de sources minéralisées."

Jan 1, 1987

By J. Duncan Crone

"A test surface Pulse EM(PEM) survey over a plunging massive sulphide lens, located in the Snow Lake area of Manitoba, has shown that it is possible to detect the body to a depth of 300 metres. Another surface survey in the Athabasca basin of Saskatchewan, clearly outlined a large, basement graphitic zone below 450 metres of sandstone cover. Deep detection of these conductive bodies was achieved by energizing large volumes of ground with a strong transmitted EM field. Such large fields also energize all other conductors present in the exploration area. Both of the above survey results indicate that more than one conductor is present. In such cases, detailed field coverage is required for accurate interpretation, and interpretational procedures that assume simple geometrical shapes should be applied with caution. In all cases geological and geophysical information should be coordinated in detail. The first test drill hole still has a high risk of missing the deep conductive body and two or three holes should be budgeted per target.Borehole Pulse EM surveys are now routinely used to help zero in on deep conductive targets. They are also proving effective in development drilling programs by outlining the edges of conductive bodies. The results of surveys from northern Quebec illustrate how they may provide more accurate shape and tonnage estimates."

Jan 1, 1985

By R. E. Martin

"The Westerose Leduc (D-3) pool, a Devonian reef reservoir situated in Central Alberta, Canada, has now been producing for over seven years. As a unit operation, the pool pro-vides an interesting example of the full exploitation of gravity segregation tendencies. The reef has a 238-foot oil column, underlain •by bottom water and over-lain by a substantial gas cap. The original hydrocarbons in place were 147.96 million STB oil and 94.4 MMMCF of Taw gas cap gas. Nine-teen producing wells on 80-acre spacing have been completed, most of which are highly productive. Gas injection operations return solution gas to the gas cap. A study of the rock and fluid properties of the pool show it to be conducive to production by gravity segregation at high rates. Monthly average producing rates have varied between 800 B/D and 8,000 B/D and have recently totalled 3,000 BID to 5,000 B /D. Recovery and performance predictions under partial pres-sure maintenance at 10,000 BID indicate an ultimate recovery of 66 per cent of the original oil in place. In the absence of pressure maintenance, recovery would be only slightly less."

Jan 1, 1960

By D. Crone, T. Watts

"The Lindsley project was a program of deep drilling to test the contact down-dip from two nickel-copper deposits, one uneconomical and the other mined out. The role of Borehole Pulse EM(PEM) was to detect the higher grade, more massive sulphide zones if they were missed by a drillhole, and to help determine geometry if the zones were intersected. Two problems appeared as the PEM survey progressed: (1) conductivity-thickness as measured by the PEM did not always relate to economic sulphides as determined by the market; (2) a pattern of unusual PEM anomalies was obtained that indicated something odd and big, but the cause was unknown. A large fold structure subsequently was indicated by a program of deepening previous holes, the third of which intersected high-grade mineralization below 1280 m. Falconbridge is in the process of shaft sinking and underground exploration.IntroductionThe Falconbridge Lindsley property is on the south rim of the Sudbury basin, 8 Ian north of downtown Sudbury. The original property was acquired by a prospector named James Stobie, who, in early August 1885, staked a showing that later became the Mount Nickel mine (Fig. I). On August 10 Stobie staked another property that would become the Little Stobie mine, and at the end of the same month he staked the main Stobie orebody.In 1888, the ground immediately west of the MOlU1t Nickel find was staked. This ground contained the Blezard deposit (Fig. 1) which was put into production in 1889 and was eventually acquired by Inco. Down-dip from the Blezard workings, on Falconbridge ground, is located the upper Lindsley No. 1 deposit which was drilled off by Falconbridge in the 1940s to 1950s. A decision to go underground on the Lindsley No.1 mineralization was made in 1969, but the project was cancelled in 1971 because of declining nickel prices. The shaft was stopped at 95 m, and the headframe and hoist were sold. Further surface exploration drilling in the 1970s discovered the deeper Lindsley No. 2 zone, but as it had grades similar to those of the No. 1 zone, it too was considered uneconomic."

Jan 1, 1992

By H. F. Naldrett

"AbstractAt the end of May, 1950, Imperial Oil, Limited, had completed a total of 192 D-3 wells in the Leduc-Woodbend field, 62 of which lost circulation in the D-3 zone for periods ranging from two hours to fifty days. The majority of the remaining wells •lost some mud without actual loss of returns. In addition, independent operators completed 69 D-3 wells, of which 9 lost circulation. Included among the latter is the now well known Atlantic No. 3 well, which blew wild out of control for seven months. The well was finally brought under control through two directionally drilled wells, but not before the derrick fell and the well caught fire. Practically all known filler materials have been used in attempt3 to prevent or regain loss of circulation, but none has been successful, except in minor cases. Ordinary sawdust has come to be the most commonly used filler material and is added to the mud before the D-3 zone is contacted. In cases of serious loss of circulation, the on1y successful method of getting returns has been the use of a series of small cement plugs.IntroductionThe Leduc field is twenty miles southwest of Edmonton, Alberta. Geologically, it is on the east limb of the Alberta syncline, in the homoclinal belt. The main productive zones are in the Upper Devonian formation and are known locally as the D-2 zone and D-3 zone, respectively (see Figure 1).The D-3 zone is a dolomitized reef with fair average porosity and permeability, and shows considerable evidence of vertical fracturing. Porosity is mainly due to moderately uniform development of vugs which are interconnected by small crevices. However, the formation is known to be, locally, extremely vuggy and in places cavernous. These latter conditions create very serious drilling problems due to the hazard of loss of circulation, particularly in the gas cap, which has a maximum thickness of 200 feet. The D-3 zone is contacted at an average depth of 5,300 feet."

Jan 1, 1950

By S. McAlister

"Falcon Concentrators Inc. has developed a high capacity centrifuge for the recovery of fine, free gold as well as other metals and minerals which were previously thought to be unrecoverable by gravity means. Development started in the early 1980's and the first commercial operation was commissioned in 1986. Gold applications include scavenging conventional gravity and cyanidation circuit tailings, cleaning gravity concentrates, cleaning flotation concentrates to melting grade, scavenging flotation tailings, and placer mining. Recent development work by Falcon has expanded the applications scope of the centrifugal concentrator to include many minerals amenable to gravity concentration including iron, tin, industrial minerals, and hazardous wastes. This paper discusses this technology including its history, present applications, and future potential. OVERVIEW OF CENTRIFIJGAL CONCENTRATIONUsing centrifugal force to enhance the separation of materials by differential specific gravity has been researched for over a century. Many attempts have been made to concentrate minerals in high gravity fields. Patents were granted on this subject as early as 1891 (see Figure 1). Patenting activity continued into the 1920's and has been relatively quiet since. It is significant that no centrifugal system of gravity concentration has been broadly accepted by the mineral processing community until recently. Much of the world's reserve of mineral deposits which are amenable to conventional gravity concentration technology (coarse-grained) have been mined and therefore there is an increasing demand for technology which can economically recover the fine-grained gravity recoverable minerals in the remaining deposits. In addition, centrifugal concentration can play an increasing role in solving environmental problems by offering an inexpensive method of concentrating hazardous materials such as uranium, plutonium, mercury, lead, and other heavy metals. The overall cost of disposing of these substances safely can be drastically reduced if they are recovered into a concentrated form prior to disposal."

Jan 1, 1992

By Glenn S. Dobby, Glenn A. Kosick

"Column flotation circuit engineering has matured to a good level of understanding regarding testing, scale-up and design. Some of the factors important to the process of implementing columns are addressed in this paper, highlighting the following issues• operating bias and the maximum achievable solids carrying rate for a column application.• internal circulating loads of full scale and pilot plant flotation columns• short-circuiting oflarge scale columns and the impact on separation selectivity• the number of stages in a column circuit and the impact on selectivity.The paper uses several case studies, from pilot plant to full scale implementation, to illustrate these design issues.1. IntroductionTen years ago, in 1984, there were very few column flotation installations world wide and the largest columns were about I . 5 to 2 m diameter or square. During the following decade there have been in the heighbourhood of 80 column installations that have been successful and profitable, as both retrofits and green-fields plants. Now, columns as large as 3 to 4 m are not uncommon. Examples of installations with many large columns include Escondida, with ten columns each at 4 m square, and P T Freeport Indonesia, with 21 columns: nine 3 m diameter columns, four 2.4 m diameter columns and, starting up in April I 995, eight 3.6 m diameter columns.During this growth period there have also been column installations that can be considered as failures. In the majority of these cases, the reason for their failure has been an insufficient installed capacity for applications where there is a high weight recovery of solids to the froth product These include zinc cleaning, copper cleaning and iron ore flotation (silica flotation from a feed that is 15 to 30 %Si02) An application with high weight recovery to the froth product makes column scale-up and circuit design more complicated. This is particularly so if a high degree of selectivity is also required while attaining a high weight recovery, which can happen with iron ore flotation in columns."

Jan 1, 1995

By G. Naud, J. Robitaille, M. Buonvino, A. Veltmeyer, A. R. Laplante

"A B6 Falcon concentrator was tested on several systems: a synthetic magnetite-silica ore, a massive sulphide gold-copper ore, a fine gold-pyrite-silica flotation tail, and a high grade gold ore in a low sulphide gangue (cyclone overflow).The Falcon demonstrated its ability to achieve separation in all cases, but with varying degrees of success. For the magnetite-silica system, separation proceeds until the concentrate bed overloads, at a mass of 300 to 400 g of magnetite. Recovery increased with decreasing particle size, down to the 25-37 µm and in some cases even the -25 µm class. Bowl geometry (angle) and gangue size distribution were the most significant operating variables. Results with the massive sulphide ore were the poorest, with gold recoveries typically around 10 to 20% at very low upgrading ratios, 1: 1 to 5: I. Gold recovery from the fine flotation tail ranged from 30 to 70% at upgrading ratios of 5 to 15; actual plant application would require a continuous unit (Falcon C20). The high grade gold cyclone overflow yielded a wide range of gold recoveries, but a very consistent relationship between recovery and mass processed. A concentrate of 0.5% Au could be processed at a recovery of 50%.The paper also presents results of a C20 application to recover fine iron from a magnetic tail. The unit is capable of recovering approximately 70% of the fine liberated iron in a high density product, with modest upgrading below 105 µm, and virtually complete rejection of the + 300 µ m product."

Jan 1, 1993

By J. Holtzhausen

"An analysis of operating costs for underground mining operations in the current global economic climate considers the financial burden for a ventilation system to be in vicinity of 30–50%. These operating costs are often overlooked by management teams in the greater scale of things when looking to save money in the procurement phase. This oversight to operational costs can be as little as the effective delivery of ventilating air to the work zone. One of the biggest opportunities for substantial savings and improvements can be realized in the selection of a quality vent duct that is suitable and fit for purpose. The key component to the selection process for quality products is a solid selection criterion that is followed during the tender process. This allows the management team to filter out unsuitable suppliers and products. The case study identifies some of the key components that were considered in the procurement and selection process for lay-flat ducting products. These included the characteristics and strength of the materials. The selection criteria also considered a ducted performance comparison that offers the best aerodynamic performance with some of the following components. • Airflow at Duct Face (m³/s or cfm), Fan Pressure (Pa), Air Power (kW or hp), Assumed Fan Efficiency, Annual Running Costs, K – Factor or Lambda, Leakage Factor, Joining Method and available Duct Lengths with weights. • Critical components considered were the current Testing standards available for: o Bursting Strength AS 4878.5, Mass AS 2001.2.13, Tensile Strength AS 4878.6, Tensile Strength AS 2001.2.3.1, Tear Strength AS 2001.2.10, Tear Strength AS 4878.7 • Other key considerations were: o Warranty Claim, Damage claims, Local storage / operations, community engagement and relationships, current testing data, previous issues, after sales service with technical assistance, etc. Hidden costs associated with product failures and operational stoppages are often not quantified during the tender process. Buyer beware. INTRODUCTION The largest constraint underground mining operations currently face are their operating efficiencies and electrical costs. The overall cost of an operations ventilation system and its components requires more focus to identify what opportunities exist to maximise efficiency and effectiveness. This tender process may not always be clearly understood and it should be broken down into fewer components to achieve quantifiable results."

Jan 1, 2019

By D. C. Brady

"Within six months from award of a project management contract, Les Mines Dumagami Limitée, Cadillac, Quebec, was operating its new hoisting facility. This was accomplished with less than a six-week shutdown of mine production while still maintaining shaft access for underground maintenance.The work involved installing a refurbished /3.5 ft diameter double drum hoist, replacing a timber headframe with a newsteel headframe, increasing the ore bin capacity from 500tons to 1000 tons, constructing a new substation, and upgrading related facilities.This paper describes the work and methods used by various contractors, Les Mines Dumagami Limitée and J.S. Redpath Mining Consultants Limited to bring this project to a successful completion. It discusses the history of the project from proposal stage through to the design, procurement, scheduling, and construction management. The paper also comments on problems that were encountered and the methods used to overcome them.IntroductionThe Donald J. Laronde Mine of Les Mines Dumagami Limitée (Dumagarni), a gold and copper producer, is located in northwestern Quebec, approximately half way between Val d&apos;Or and Rouyn. The mine started production in the spring of 1988 and the first gold bar was poured in June 1988.Following a request by Dumagami, on February 22, 1989, J.S. Redpath Mining Consultants Limited(Redpath) delivered a proposal to increase hoisting capabilities from 1500 tpd to a minimum of 2500tpd. Although various concepts were considered, Redpath proposed a new hoist house along the same shaft axis as the existing hoist, and located on the site of the existing substation. They would then provide a new substation, replace the headframe with a largersteel structure , gain extra storage capacities by increasing the bin heights, and raising the roof of the bin house accordingly.Although underground mining would have to be stopped for a month, the mill production would be maintained by feed from Dumagami&apos;s open pit.Figure 1 shows the original plant layout and Figure 2 represents the general arrangement after the project was completed . Table 1 compares the original hoisting facilities to the new facilities.On March 2, Dumagami awarded Redpath a contract that included preliminary engineering, detailed engineering, procurement and contract administration, and later added construction management. The preliminary engineering refined the initialconcept, selected major equipment, and prepared schedules and capital cost estimates for the total project."

Jan 1, 1991

By H. Cay, J. Zachwieja, T. Esplin, R. Ravenelle, T. Olsen-Tank

Barrick Goldstrike mine utilizes a carbon-in-leach (CIL) circuit to simultaneously leach gold into solution with cyanide and adsorb the gold-cyanide complex onto activated carbon for further refinement. If the gold bearing ore contains a significant amount of native carbonaceous material, gold cyanide can be adsorbed at these sites instead of onto the desired activated carbon and the gold is effectively lost to tailings in a detrimental process known as "preg-robbing." The preg-rob effect is considerably reduced by treating the ore with a surfactant, which is hypothesized to adsorb to and passivate the native carbon surfaces. Past laboratory and pilot studies have consistently demonstrated significant gains in gold recovery after treating carbonaceous ore with surfactant. With success in bench and pilot scale testing, a plant trial was conducted at Barrick Goldstrike to evaluate the feasibility of using an alkoxylated fatty amine surfactant (Ethomeen T/12) to aid in the leaching of high preg-robbing ores. This paper analyzes the performance of the surfactant during the plant trial in addition to the problems that occurred during the trial period. Suggestions for improvement are also discussed.

Jan 1, 2014

By Jérôme Girard, Shiu Kam, Sue Longo

"Historically, tailings management in a northern climate has involved the deposition of tailings into the Tailings Management Area (TMA) as conventional slurry. This type of system is obviously viable but presents challenges that are difficult to manage as circumstances change over the life of mine. These issues can include:? Increases in mill throughput, and? Life of the TMA for the life of mine.This case study will present how thickened, high-density, non-segregating tailings are used as an alternative to conventional slurry disposal to achieve greater storage capacity and enhanced environmental performance for a gold tailings facility in a northern climate. This paper will focus on how this change in deposition strategy accommodated the increased throughput of the mill and the increased life of mine. Specifically, the paper will discuss the addition and integration of new processes to the exiting mill system to accommodate the tailings management issues. It will highlight the challenges from laboratory testing to pre-feasibility to the engineered design of the thickened tailings system implemented at Musselwhite Mine.BACKGROUNDGoldcorp Canada’s Musselwhite Mine, in Northwestern Ontario (120 km north of Pickle Lake), is an underground gold mining operation that began production in 1997. The current mill throughput is about 4000 tpd (1.4 Mtpa). Gold extraction is based on a CIP process with cyanide destruction.The existing tailings management area (TMA) is located about 2 km southwest of the mill complex. The TMA is contained by high ground to the north and to the west and flanged by a moraine ridge along the south side. A number of dams have been constructed along this ridge. The dams were first built in 1996 and subsequently raised in 2000 and again in 2005. Excess tailings pond water is discharged to a polishing pond then released to the environment via a wetland.The TMA was originally designed to contain 13.7 Mt of tailings under a ponded surface for closure. The water cover was to inhibit adverse long-term environmental effects because the tailings contain pyrrhotite and other sulphide-bearing minerals that are potentially acid generating. The design was modified during Stage 3 Construction in 2005 to expand the storage capacity to 17.3 Mt (Golder, 2005). As of end of 2009, over 16 Mt of tailings had been deposited in the TMA. The slurried tailings were historically deposited at 50% solids."

Jan 1, 2011

By W. Standifird

"Cohesive fracture is a mechanical model widely used for modeling quasi-brittle fracture in rocklike materials. This work discusses use of this model to simulate quasi-brittle fractures generated by injection stimulation during the process of cuttings reinjection in West Africa. Cuttings reinjection is an engineering practice used for disposal of drilling waste. During this process, hydraulic fractures are created at the target formation and milled cuttings are injected with fluid. In practice, this process must remain in compliance with environmental regulations and zero-discharge policies. The purpose of this study is to determine the following factors of injection design for a field in West Africa: (1) pumping pressure capacity required to successfully perform the injection and (2) the injection rate for injection performance and the value of fracture width under injection.A simplified three-dimensional (3D) finite element model (FEM) was built. A poroelastic plastic damage model was used for simulation of the cohesive crack prorogation within the target formation. For simplicity, fracture development in both horizontal and vertical directions was simulated separately. In this way, the computational burden for one calculation was reduced to a reasonably low level, without losing accuracy of the model. Loads of the model include fluid injection and gravity, which balances the initial geostress field. Various values of injection rate were used in these calculations to determine the most reasonable value of injection pressure. The capacity of pressure of a pumping device was determined using this optimized value of injection pressure.Results in values of width and length of fractures created by the injection are presented. Injection pressures at bottom-hole (BHP) corresponding to each value of injection rate are also given. Numerical results for fracture generation and propagation in a horizontal direction were visualized. The pumping pressure capacity required to fulfill the cuttings reinjection work was determined based on the numerical results of optimized injection rates and pressure. The fracture width was determined using the given pumping pressure. The length and height of the fractures was determined using pumping pressure along with the required volume of cuttings waste to be disposed of into the formation.This work presents a case study of 3D finite element modeling of hydraulic fracturing generated by cuttings reinjection. The results of the optimized injection rate and pressure provide a best practice and a useful reference for cuttings reinjection analyses in this region."

Jan 1, 2015