Search Documents

By Ben Murphy, Tomi Maksimainen, Antti Rinne, Ishmael Muzinda, Toni Mattsson

"A 500m3 flotation cell was commissioned during 2014 at the Kevitsa Mine in northern Finland working as the first rougher in the copper flotation circuit. Treating around 850tph with an average grade of 0.3% Cu, the TankCell® e500 has run with an average copper recovery of 71% and an average enrichment ratio of 50 during early optimization test work. In addition the cell has proved to be very energy efficient, being operating with a specific energy of around 0.4kW/m3 under production conditions.A review of the installation and operation of the TankCell® e500 at Kevitsa will be presented. Metallurgical performance of the cell during the operating period will be discussed on the basis of on-line analysis and the metallurgical samples collected during early optimization campaigns.IntroductionThe past three decades have seen a rapid increase in the size of mechanical flotation cells. This has been largely driven by demand from the copper industry to process larger volumes of material due to combination of declining head grades and the desire to benefit from the economies of scale (Lynch, Harbort and Nelson 2010). During this period Outotec has been at the forefront of development of large flotation technology with an enviable scale-up track record; 100m3 (1995), 160m3 (1997), 200m3 (2002), 300m3 (2007), 500m3 (2012) to the largest commercially available cell at 630m3 in 2013. This scale-up methodology has been developed, tested and validated (Elgueta et al., 2009; Coleman & Dixon, 2010) by the large installation base of cells in the 300m3 size class operating (over 400). The learning from large cell operation are then reviewed and incorporated back into new designs and scale-up practices (Murphy, Miettinen, and Yanez, 2014)."

Jan 1, 2016

By R. Jackman, D. Koningen, G. Wilcox

"Gowest Gold Ltd. is in the process of developing the Frankfield East gold deposit located along the largely undeveloped Pipestone fault northeast of Timmins, Ontario. In addition to resource development and environmental permitting work the company has had an ongoing program of metallurgical and engineering studies aimed at evaluating options for processing the Frankfield East ore. Mineralization at the Frankfield project contains arsenopyrite and pyrite as the major sulphide minerals. Bulk flotation of all sulphides results in extremely high gold recovery. However, the gold is almost entirely associated with the arsenopyrite fraction of the ore and is refractory in nature requiring preoxidation treatment. Selective flotation was investigated to recover a gold-arsenopyrite concentrate thereby reducing the mass which would be subjected to further gold processing. As part of this work, a pyrite concentrate low in arsenic content was also recovered that would be suitable as a source of sulphur for a smelter (or other pyrometallurgical facility). Production of separate arsenopyrite and pyrite concentrates is frequently examined but rarely adopted due to the distribution of gold between the two products or the inability to achieve adequate separation. Several flowsheet options were investigated in the study. The best results were achieved following a sequential flotation flowsheet. The flowsheet configuration was key to meeting the targets for the two products. In this paper, the various options investigated are reviewed and the results of the final flowsheet are presented. The overall plan by Gowest was to evaluate all process options to bring the Frankfield East deposit into production. The ability to effectively separate the arsenopyrite and pyrite components in the ore provides Gowest with added opportunities to pursue both short and long term production scenarios."

Jan 1, 2012

By C. Blawert

In spite of various corrosion studies on HPDC AZ91, there is no clear indication which microstructure gives the best corrosion performance. The skin with its fine microstructure is sometimes reported to have the best corrosion resistance, but there is no clear definition of the skin. If the skin is the outermost part of the casting and nothing is removed from it, then it is contaminated and the corrosion resistance is low. If the outermost skin is removed (about 25 µm) then a better corrosion resistance can be obtained. However this does not automatically mean that there is no other region in the bulk of the casting which could have a similar or even better corrosion resistance. Indeed, the corrosion measurements including potentiodynamic polarization and long term electrochemical impedance spectroscopy (EIS) revealed a lower corrosion resistance of the original as-cast skin about 100 pm thick. The thickness of this region is more or less independent from the thickness of the casting section. The surface region is free from any dendritic grain growth which influences the amount and distribution of the 13-phase and therefore the distribution of the most important alloying element Al. This could explain the different corrosion behavior. Further reason can be found in the enrichment of some impurities such as Fe in the near surface.

Jan 1, 2006

By Rees J. Llewellyn

High chromium white irons can be formulated to provide required combinations of abrasion and erosion wear resistance, toughness and capability to withstand corrosion attack. As a consequence, they are used widely in casting form throughout the mining/mineral processing industry, particularly as components for slurry pumps and also as mill and crusher liners, laminated wear plates in chutes and hoppers and in valves, nozzles and cyclones. Traditional cast chromium molybdenum and high chromium white irons for wear applications are covered in ASTM A532 Classes 11 and 111 and are also available as comparable proprietary alloys. They rely on heat-treated, hypoeutectic microstructures containing a high volume fraction of very hard eutectic/secondary metal carbides and martensite to provide extremely high wear resistance. The ability to increase the carbide volume fraction and hence achieve higher wear resistance, has been limited because of severe casting difficulties encountered when carbon and chromium contents are raised and hypereutectic alloys with structures also containing coarse acicular primary metal carbides are produced. The limitation has been overcome and cast hypereutectic chromium white iron pump components have established themselves in a wide variety of mineral processing service applications. Comparisons will be made between the microstructures and wear test performance data for the various alloy types and details will be provided of the service performance improvements that have been achieved through the use of hypereutectic chromium white irons.

May 1, 2004

By C. Han, S. J. Zhou, Y. B. Shen, D. Z. Wei, P. Fang

"Collecting property of two hydroxamic acid collectors have different type of nonpolar structure to hemimorphite has been comparatively studied via monomineral flotation test, and the reason causes different collecting performance has been discussed from the view of relationship between molecular structure and collecting property. The flotation tests results show that C5-9 hydroxamic acid has an unbranched linear alkyl nonpolar group shows better collecting property to hemimorphite than cyclohexyl hydroxamic acid which has a naphthenic nonpolar group. FTIR detecting results show that the adsorption type of collector adsorbed on hemimorphite surface is chemical adsorption. Calculation results of polar group’s geometric structure parameters, polar group’s electron density distribution, octanol-water partition coefficient (logP) and molecular frontier orbital energy show that the key factor caused different collecting property of two collectors to hemimorphite is the logP; unbranched linear alkyl nonpolar group is more conducive than naphthenic nonpolar group to make hemimorphite particle more hydrophobic.INTRODUCTIONZinc-bearing mineral recovered from lead-zinc ores is the main source that people can obtain zinc resource from nature. However, natural sulfide ores are currently getting depleted steadily for the primary zinc source. In order to satisfy the future demand of zinc resource, there is an obvious recognition that the recovery of zinc oxidized minerals from the ores is a crucial alternative (Hosseini & Forssberg, 2007; Navidi Kashani & Rashchi, 2008).But the fact that can’t be ignored is the flotation of zinc oxidized minerals is much more difficult than that of zinc sulfide minerals, which is mainly due to the flotation characteristics of these zinc oxidized minerals such as lower selectivity and higher reagent consumption, as well as complex and variety of lead-zinc ores. Presently, there have been many various beneficiation technologies used for recovering zinc oxidized minerals and dealing with ores for recovering metallic zinc such as flotation and hydrometallurgy (Abkhoshk, Jorjani, Al-Harahsheh, Rashchi, & Naazeri, 2014; Önal et al., 2005). But from an overall perspective, flotation is the most common method used for the beneficiation of zinc oxidized minerals, and there have been extensive investigations conducted on the flotation of zinc oxide ores (Ejtemaei, Gharabaghi, & Irannajad, 2014). Until now, the most well-known method used commercially for the flotation of zinc oxidized minerals is sulfidization with sodium sulfide and flotation with a cationic collector of amines containing from 8 to 18 carbon atoms. However, a major problem for this method is the large amount of fines and slime results in the increase of reagent consumption and promotes the phenomenon of slime-coating. For preclude this negative effect, the de-sliming and processing optimization is indispensible (Peres, Borges, & Galery, 1994; Salum, de Araujo, & Peres, 1992)."

Jan 1, 2016

By Andréa Lagacé

"The milling of sulphide ores inherently generates “thiosalts”, a series of partially oxidized sulphur oxyanions (S2O3 2-, S3O6 2-, S4O6 2- etc.), which make control of effluent treatment systems difficult because their natural oxidation produces acid with the potential to lower the pH within the treatment system and/or receiving environment.At the Xstrata Copper Kidd Metallurgical Site, thiosalt oxidation in the Tailings Management Area continues after buffer storage Ponds A and C where lime is added to precipitate metals and elevate the pH to within the required range for discharge. If the additional acidity generated during the continued process of thiosalt oxidation is not neutralized there is a risk that the final effluent will be non-compliant with regulated standards.To mitigate this risk, in 2007 a full scale pilot trial was conducted with hydrogen peroxide in order to force the complete oxidation of thiosalts prior to the lime treatment stations. This method of chemical oxidation had been shown to be effective at Xstrata Zinc’s Brunswick Mine. The pilot results indicated that a maximum of 50% of the stoichiometric quantity of hydrogen peroxide is required to reduce the thiosalt concentration in the No. 2 thickener overflow stream (feed to buffer storage Ponds A and C) to less than detection (10 mg/L); however, treatment was only effective in the presence of a 20 mg/L iron (Fe) catalyst. Since the hydrogen peroxide addition point at the No. 2 tailings thickener overflow typically contains <1 mg/L total Fe, a second reagent, ferric sulphate, was used to increase the total Fe concentration to the required level. This paper describes the set-up and results of the pilot trial which were used in the design of the full-scale plant.INTRODUCTIONTailings Management Area OverviewXstrata Copper’s Kidd Metallurgical Site, located in Timmins, Ontario, is an integrated metal refining facility producing copper, zinc, cadmium, indium, liquid sulfur dioxide, and sulfuric acid from third party custom feeds, and mineral concentrates recovered from its 7,800 tonne per day mill."

Jan 1, 2010

By J. B. Scott

"A computerized cost estimating program developed with the use of the Lotus 1-2-3 spreadsheet program has produced dramatic savings in preparing estimates for operating costs, equipment fleet size and manpower requirements for underground mines.The program is used by Dynatec to support its consulting engineering projects, particularly feasibility studies. The &apos;first principles&apos; approach is used to prepare detailed estimates under direct labour and supplies categories and maintenance costs for each mining operation . User notes have been developed to guide the estimator and ensure appropriate consideration is given to the specifics of the particular mine.A typical case history is illustrated and the ease by which alternatives and sensitivity analyses can be prepared is demonstrated. IntroductionHistorical MethodsMining engineers have used one or a combination of methods to prepare operating cost estimates for new or existing mine s. Operating companies have access to historical cost data and generally use this for preparing estimates. Consulting engineers do not usually have direct access to such information and must rely on mining companies (the present or previous clients); publications (text books, equipment manufacturers manuals, CMJ reference manual, etc.); annual reports (applicable to public companies); previous studies (to be used with caution as conditions change from mine to mine); and first principles (the subject of this paper), for cost information:Definition of First PrinciplesA first principles approach to cost estimating considers individual primary work elements of an operation. Quantities of work items are developed from the mine plans, production rates, geographic and physical layouts etc. The knowledgeable estimator, assisted by experienced operations personnel, can assign appropriate resources (equipment, labour, supplies and services) to each work element and establish productivities. Completion of the cost estimate is then largely arithmetic."

Jan 1, 1988

By C. Pelley, S. Kelebek, G. Kunzel, S. Gregersen, M. Pollanen

A series of small-scale tests was conducted to evaluate the effect of micro-fracture development, imposed by blasting, on the material properties of the rock as well as its resistance to crushing and grinding. The uniaxial compressive strength, tensile strength, Poisson’s ratio, Pwave, S-wave velocity, point load test index, crushing, and grinding work indices were evaluated for samples without any blasting load and for samples which had received a variety of blast loads ranging from a single impact with a lowstrength detonating cord to a combination of impacts at different times and significant impacts with powder factors close to those used in practical blasts. It was shown that the rock mechanics parameters change even at low impacts, suggesting easier crushing of the rock. Damage values appear to be affected by timing as stress wave superposition affects the damage process. Fragmentation is achieved at higher impact levels while work index modification of the fragments is also observed when high powder factors are used, suggesting improvements in grinding.

Jan 1, 2006

By Charles Kocsis

Over the last few years a multi-faceted feasibility study has been evaluating the introduction of hydrogen fuel cell powered equipment into underground mines to replaced diesel engine powered equipment. The analysis has shown that under normal operating conditions fuel cells could at the very least be an environmental and health benefit by eliminating combustion engines and their unwanted by-products. However, they could also generate significant reductions in the amount of ventilation a mine needs to supply when compared to dieselized operations; this would further decrease a mine?s energy consumption, its associated greenhouse gas impact and also reduce a mine?s significant ventilation associated costs. Fuel cell powered equipment also has the advantage of lower noise and heat production compared to their equivalent diesel powered counterpart. The degree to which fuel cells can generate ventilation benefits in underground mines depends upon a number of operational parameters and mine specific qualifiers such as current ventilation control or management, mine depth, inherent dust conditions and minimum velocity requirements. However another major consideration in the introduction of fuel cells in underground mines will be the safety requirements associated with diluting and removing the potentially explosive hydrogen in the event of a gas leak. In outside surface applications, it is possible to use dispersion, buoyancy, time, and lack of ignition sources as mitigating factors in deriving a low risk of an explosion. However, in underground operations these factors change, dispersion and buoyancy are limited; time may not be available and in non-coal mines ignition sources are not typically controlled. When a hydrogen leak occurs, the availability of sufficient ventilation to dilute and effectively remove the gas will be critical, consequently ventilation may be the prime risk controlling factor. In this paper, the authors evaluate the potential benefits of replacing diesel engines with fuel cells in powered production equipment, discuss the mitigating qualifiers that could limit ventilation savings and evaluate solutions to retain and maintain an additional ventilation capacity in the event of an emergency situation such as a hydrogen leak from the fuel cell stack or its distribution system.

May 1, 2007

By S. Makni, A. Faucher, F. Robichaud, A. Bouajila

"Optimizing the ball charge in a grinding mill may be needed to maximise throughput or alternatively, to achieve proper product size in more challenging situations. Efforts to optimise the ball charge however are essentially empirical and suffer from the lack of appropriate, accessible and reliable tools. To address these limitations, a new model-based technology was developed that relies on 3D Discrete Element Method and population balance techniques: it takes on the form of a simulator that aims to significantly decrease the time required to optimise the size distribution and the grinding media load within a ball mill. This paper summarizes the research work related to the development of this simulator. The calibration of the different constituting sub-models will be highlighted. The successful use of the simulator to predict the effect of ball make-up on the grinding product size distribution in one plant is also reported.INTRODUCTION Adjusting the characteristics of the grinding media charge in grinding mills holds significant potential for optimisation of mill performance. For example, properly adjusting the ball size distribution in a ball mill can help achieving specified targets for final product size distribution and/or throughput capacity. However, several problems appear when reviewing the process and the available tools to optimise ball mill load: • The current empirical simulation tools are lacking with regard to the ability to predict the performance of grinding when changes to mill ball make-up are made; • Generally, these tools estimate the top size of the charge so it is difficult to predict the effect of mixed ball make-up; • As the quality of prediction of these tools is low, the operators try to optimise the ball charge by a ""trial and error"" method and proceeding with conservative changes. The influence of these changes on grinding performance is often less than the measurement precision and the improvements then remain imperceptible; • A change in ball make-up may require an average of about 6 months waiting period before reaching the stationary state of mill ball load. This exercise is due to be costly if applied change decreases the mill performance. In its effort towards the comminution process optimisation, COREM R&D portfolio had addressed the herein described opportunity during the last five years This paper describes the technology already developed for the optimisation of ball charge. It takes on the form of a simulator that aims to predict the evolution of the grinding media load, the grinding energy available in the ball mill and the final product size distribution. The simulator was first validated in a pilot scale ball mill and then applied in an industrial case."

Jan 1, 2012

By Lynn M. Gould

Syncrude Canada operates the largest oil sands crude oil production facility in the world and produces over 13 percent of Canada?s total oil requirements. To do this, Syncrude mines the oil sand in open pits, extracts the raw oil known as bitumen from the sand using water-based processes and upgrades it into sweet light crude oil by fluid coking, hydroprocessing, hydrotreating and reblending. The final product, Syncrude Sweet Blend (SSB) is sent by pipeline to three Edmonton area refineries and then to pipeline terminals which ship the SSB to refineries in Canada and the United States. As parts of the Mildred Lake Base Mine reached their economic life, they were replaced with new facilities at the Aurora satellite mine. Aurora is situated on Oilsand Leases 10, 12, and 34, 35 kilometres northeast of the Mildred Lake facility. (Figure 1) In 2000 the first hydrotransport low energy extraction production train started up at Aurora. A second production train is scheduled for start up in 2003. Open pit mining at Aurora occurs using two hydraulic shovels, two cable shovels, and trucks ranging from 320 ton to 380 ton payload capacities.

May 1, 2002

By John Russell

"The South American mining community leads the world in recognition and adoption of the latest grinding mill relining technologies. Clearly this region has recognised the benefits of improved relining performance.Six of the seven RUSSELL TWIN 8 Mill Relining Systems, ordered to date, are either operating or being manufactured for South American mine sites.This paradigm shift, towards very short relining times, aims at displacing mill relining activities from the critical path of concentrator maintenance shutdown schedules.The first uses of the RUSSELL TWIN 8 Mill Relining System have seen some of the highest SAG mill new liner placement rates ever observed by RME, as would be expected with two, independent Machines working simultaneously in the one mill.The liner-replacement-rate, averaged over the whole reline, is good (27% improvement over single Machine System in the same mill) but short of full potential. This modest result can be attributed to reline crews unfamiliarity with RUSSELL TWIN 8 System operation.This paper compares a sample of conventional (single machine) RME Mill Relining System performance data with one ‘double head’ mill liner handler by others. Early performance of Escondida’s new RUSSELL TWIN 8 System performance is then compared with recent single Machine data from Escondida, immediately prior to RUSSELL TWIN 8 commissioning. RME and Escondida look to constantly improving RUSSELL TWIN 8 System performance as full operational familiarity is achieved.Also, the preparation of this paper revealed a need to develop a global industry standard for mill relining data collection. A web based platform, to develop and then distribute standardised data collection templates, is discussed in Annexure 1."

Jan 1, 2010

By T. Deng

Flotation of rare earths is complicated by the number of mineral classes that carry rare earth elements, including carbonates, phosphates, and silicates that often co-occur within the same deposit. Gangue constituents often belong to the same mineral classes as the rare earth minerals themselves. Chemical regimes developed for specific separations employ customized combinations of collectors, modifiers, and depressants that are not directly translatable to other operations. In this rougher flotation case study, a reagent suite including phosphate ester and sulfosuccinamate, originally developed for the recovery of bastnasite and monazite from silicate hosted ore, could not be applied to a synchysite ore hosted in carbonate gangue because the suite was aimed at silicate gangue rejection only. The separation of a fluorocarbonate mineral from carbonate gangue required a different chemical regime involving the use of hydroxamate and sodium silicate. Maximizing rare earth recovery was complicated by the presence of slimes. The effect of desliming and the increase in grind size was explored.

Jan 1, 2014

By Eric Konigsmann, Doug Spence, Scott Jones

"The Williams Gold Mine is located in the Hemlo camp of Northwestern Ontario and is one of Canada’s largest gold producers with annual gold production of 400,000 ounces. The operation is owned and operated as a 50:50 joint venture between Teck Cominco Limited and Barrick Gold Corporation.In July 2002, the decision was made to introduce paste backfill produced from mill tailings as the primary backfilling method in the mine and to decommission the existing cemented rock fill system. This required a fast track design to be completed for both a surface paste backfill plant and an underground paste distribution system followed by an intensive construction phase through the fall and winter of 2002/2003. The paste system was commissioned on schedule in late April 2003 and was in full production within 4 weeks of the initial start up. Overall, the project duration was only 42 weeks from initial project release to commissioning and it was completed $2 million under the budget of $14 million.This paper presents an overview of the lab testwork and process flowsheet design, process control methodology and describes the construction and commissioning phases of the project. Preliminary paste plant performance and operating cost data is also presented.IntroductionThe Williams Gold Mine is located in Northwestern Ontario adjacent to the Trans Canada Highway in the Hemlo Gold Camp as shown in figure 1. The mine currently produces approximately 400,000 ounces of gold annually and is owned and operated as a 50:50 joint venture between Teck Cominco and Barrick.The deposit was discovered as part of the Hemlo gold discovery in 1981 which led to the development of three mining operations within a 2 kilometre radius. The neighboring operations are the Golden Giant Mine, currently owned and operated by Newmont Gold, and the David Bell Mine, currently owned and operated by the same joint venture which is running Williams. David Bell ore is blended and milled in the Williams concentrator."

Jan 1, 2004

By Raymond C. Voige

"The use of current electronic technology in the design of new underground mine communications equipment is providing improved and expanded voice communications which can, in turn, contribute to improved productivity and safety. A review of equipment that is now available or under development Includes the following categories:WIRED SYSTEMSI.Pager phones with selective calling, audible and visual alerting and message indicator.2. Mufti-conversation pager phones that use multiwire cable ormultiplexing techniques.WIRELESS SYSTEMSLow-and medium-frequency inductive systems utilizing ""near"" magnetic fields for both vehicular and personal communications.Wired SystemsCommunication systems in underground mines have evolved slowly in many parts of the world. For many years, magnetotype telephones were the only means of communication from one mine level to another and to the surface. These units were located near the shaft and communications to the working areas were limited."

Jan 1, 1981

By A. P. E. Dirige

Extensive field study has been performed to assess the capabilities of thin sprayon liners (TSLs) and conventional spray-on support systems for preventing rock and support material damage that often results due to mining-induced rockbursts. Support performance was studied using field scale explosive detonation trials to simulate dynamic failure effects that are known to develop during typical rockburst events. Multiple seismic and high speed photographic monitoring techniques were used to provide detailed information concerning rock motion, surface fracturing, ejected fragment motion, and support liner survivability characteristics. Results of this study have demonstrated that TSL?s and variant layer combinations may be as effective as or better than conventional support materials for mitigating rockburst or like damage in highly stressed mine environments. In this study, field results have been verified using numerical modeling procedures to better understand the support behaviour of TSLs when subjected to highly stressed mine environments and mining-induced rockbursts, a factor that is essential when designing any rock support system. A series of numerical modeling assessments were conducted using FLAC3D modeling of a half circular TSL-lined tunnel, influenced by anisotropic stresses and simulated mining-induced rockbursts, to investigate the support potential of TSLs under prototype conditions. The effect of a mine rockburst was simulated using the three-dimensional dynamic analysis option of FLAC3D. Results of TSL-lined tunnels in highly stressed and mine rockburst conditions indicated exceptional effectiveness of TSLs for suppressing rock deterioration resulting from stresses and rockbursts. The rock support potential of TSLs on tunnel surfaces was compared with that of thin shotcrete linings, and results indicated that thin spray-on lining products currently available may be equally as effective in support as shotcrete materials.

May 1, 2009

By M. G. Dellow, D. W. Hendriks

"In early 1988 the decision was made by Noranda Minerals Inc. to install pressure filters at the GECO mill to replace the vacuum disk filters and bunker-C fired rotary kiln dryers. Two filters were installed, one for copper concentrate and one for zinc concentrate. Completion of the project was scheduled for the third quarter of 1989. The filters were made operational in October 1989. Some work remains to be done yet on loadout conveyors for total project completion. Capital expenditures for the project have been approximately $2,700,000 to date. The paper describes the selection criteria for the filter, the installation, startup and associated problems.1. INTRODUCTIONThe filter model chosen for the project was the Verti-Press model VP-50-6(7) (Figures1 ,2 and 3) by Filtra Systems of Farmington Michigan, USA. The decision to purchase the Filtra Systems filter was based on gaining familiarity with a different, mechanically simpler pressure filter than the Larox design and to a lesser extent a necessity for repairs to the the disc filter, rotary kiln dryer system used at the GECO operation for its' copper and zinc concentrates. The fact that it is manufactured in North America was an important consideration. The same basic principles of pressure filtration as the Larox machine are used but the implementation is quite different and somewhat simplified with some interesting innovations. 2 filters were installed to allow direct and immediate comparison of the same machine on both fine and coarse materials. Copper concentrate is reground for cleaning on the flotation circuit while zinc is not. Screen analysis of composited samples of concentrates for 1988 indicated that expected copper concentrate would be approximately 66% minus 400 mesh and zinc 50% minus 400 mesh (Tables 1 & 2).The filter is composed of six horizontal chamber module layered vertically and held together in a frame by 1 O large bolts; torqued down to 4000 ft-lbs. 6 individual belts are used; each with its own drive system. The belts themselves are of a 3 piece design with a filter cloth portion, a support belt and a rubberized intermediate portion. They are held together with steel clipper lacings. A basic description (1) of the filter operation is as follows. ""The horizontal filler chamber is closed by hydraulically pressurizing seals across each end of the filter chamber to 200 psi. The feed pump then pumps slurry into the filter chamber. Suspended solids are retained on the filter belt and the filtered solution drains into a lower drip tray and flows from the filter by gravity. At the end of the filtration or feed cycle, a rubber diaphragm in the filter chamber is pressurized hydraulically to 100 psi pressure. This removes all free liquid from the filter chamber and the filter cake. After the diaphragms are retracted the filter cake is blown with compressed air to remove any residual cake moisture. The seals are then retracted and the belt is advanced to discharge the filter cakes. During the cake discharge the belts are washed with a spray header located at the drive end of the filter. The belt assemblies move one (1) complete revolution during the cake discharge cycle. The cycle automatically repeats until the filter is shut down by the operator."

Jan 1, 1990

By W. J. Pearson

"""POTASH"" is a term applied to the compounds of the element potassium (K) and when used in agriculture and industry is ex-pressed in terms of potassium oxide (K2O), regardless of the actual com-position of the compound. When a chemical analysis is made of a fertilizer, the amount of K is deter-mined and then calculated to the equivalent amount of K2O. However, the compound K2O does not exist in nature. Most of the world's potash supply is derived from mineral deposits similar to those in Saskatchewan and New Mexico. However, there is some production from concentrated surface brines such as occur in Searles Lake, California; Salduro Marsh, Utah; the Dead Sea; and from well brines in Micl1igan."

Jan 1, 1960

By Roy Lindsay, Paul O'Hara, Gary Halverson

"The New Britannia Minesite is located in Snow Lake, Manitoba, 420 miles north of Winnipeg (figure 1). The mine previously operated from 1949 to 1958 extracting some 5.39 million tons of ore at a 0.150 opt gold grade. From 1959 to 1986 the property was held by Nor-Acme and Hudson Bay Exploration and Development and in 1987 High River Resources Ltd. Optioned the property, dewatered the mine and conducted a diamond drill program between the 1 780 and 2400 levels. In 1988 two companies, Nor-Acme Mines Ltd. and High River Gold Mines Ltd., negotiated an option agreement with INCO Gold whereby !NCO assumed management control of all site exploration work. During this period, a bulk sample of 10,000 tons was extracted from the 1780 level with no further exploration recorded after its removal. Both Hudson Bay Exploration and Development and INCO Gold conducted feasibility studies on reactivating the property but at a calculated capital cost of Cdn $70 to $80 million found the rate of return on their investment unacceptable.In 1991 !NCO Gold merged its interest with the assets of TVX Gold Inc. and in February 1994 TVX Gold Inc. and High River Gold Mines Ltd. entered into a joint venture partnership to develop the Snow Lake property, naming TVX Gold Inc. the operator. Upon completion of a feasibility study in April 1994 by Bharti Engineering Associates Inc., a decision was made to reopen the Britannia Mine at an established project cost of US $33 million.Project construction commenced in July 1994 with the hoist house excavation. The first concrete for the hoist house level footings was poured on August 4, 1994 and the project was completed on October 1, 1995 at a cost of US $36 million. The first gold pour took place November 4, 1995.This paper not only presents the metallurgical aspects of the operation but also describes the novel approach used to complete the design and construction of the site facilities."

Jan 1, 1996

By R. G. Hamm

A brief outline covering the shovels and draglines in use in the open-pit mines of Western Canada, including British Columbia, Alberta and the Yukon, is given, followed by the procedure for the selection of the correct wire rope for each application. Such fa ctors as wire rope constructions, lay directions and types of cores are mentioned. Once the correct wire rope has been selected, there are variousfactors that can affect the service fife ofthe rope and the reduction ofdown-time during rope change-overs. Factors such as hairpin winding, types of Becket loops, and shovel drum and bail adaptors are described.

Jan 1, 1979