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By K. U. Kainer, A. Stark, D. Tolnai, M. Hehenberger, C. L. Mendis, N. Schell, N. Hort

Samples of an as extruded Mg-6Zn-0.6Zr-0.4Ag-0.2-Ca (wt.%) alloy was compressed at room temperature and at 250°C. The in situ deformation tests were performed at the P07 (HEMS) beamline of PETRA III, DESY, with a modified DIL 805 A/D dilatometer with to Kapton windows on the sides and the induction coil opened for the beam to transmit the sample. The deformation rate was 10-3 s-1 the samples were deformed to failure. The diffraction patterns were recorded every 3 s with a Perkin Elmer 1621 Flat Panel Detector. The results reveal that different deformation mechanisms are activated during compression at a given strain value. At room temperature twinning is the dominant deformation mechanism, while at elevated temperature dynamic recrystallization occurs while the contribution of twinning to deformation is significantly reduced. The compressed samples were further investigated with conventional metallography and SEM-EBSD to determine the volume fraction, the type of twinning and the strain retained within the grains. The parallel testing of pure Mg samples under the same conditions allows comparison of the compression behaviour of the ZKQX alloy with Mg.

Jan 1, 2014

"The first SkimAir flash flotation cell was installed in Outokumpu’s Hammaslahti Copper Concentrator in 1982 to prevent overgrinding of soft sulphides in the milling circuit. Since this first installation the popularity of the flash flotation has fluctuated depending on metal market conditions and regional preferences. Units have been installed in many commodities including copper, lead, gold, PGMs, silver and nickel. Though it has been successfully employed in many operations around the world, flash flotation technology is still not well understood by many in the mining industry. This paper will discuss aspects of flash flotation flowsheet development along with some of the metallurgical and engineering considerations required to successfully incorporate flash flotation into new or existing milling circuits. This paper will also try and debunk some of the myths that exist around flash flotation cells and their operation. Case studies of flash flotation implementation will be discussed.IntroductionModern flash flotation technology was developed several decades ago by Outokumpu, with the first commercial installation of this technology being at the Hammaslahti concentrator in Finland in 1982 (Kallioinen & Niitti, 1985). This was a relatively modestly sized SK80 cell producing final grade copper concentrate directly from the flash flotation cell operating in the grinding circuit. Since that time the size and number of flash flotation cells installed globally has grown considerably to the point where today, it is a widely known application of flotation technology for amenable ores. Owing to their long history in developing the technology, Outotec are the market leader with their SkimAir range of flash flotation cells. Though there is a general awareness of flash flotation process in the mineral processing industry, there is a lack of detailed understanding of the process and the benefits it can provide to new and existing operations."

Jan 1, 2017

By E. A. Lowe, A. F. Bellamy, J. W. Smith

"In the autumn of 1977 Bethlehem management initiated feasibility studies on recovery of by-product molybdenum from concentrate produced at the existing Highland Valley mining operation. Over the fall and winter months test work was carried forward concurrent with design, flowsheet, equipment specification and cost studies. The decision was made to go ahead with a 200 ton-per-day treatment plant. Construction started in early 1978 and progressed to an initial start-up stage in mid-June. Full operational status was reached in August 1978. Operational results through August 1979 are presented. INTRODUCTIONBethlehem Copper Corporation operates a 20,000 ton-per-day Open Pit Mine and Flotation Plant located in the Highland Valley, some 30 air miles Southwest of Kamloops and 20 miles Southeast of Ashcroft, B.C.Two open pits are worked; the Iona Pit with limited reserves of higher Mo content, and the lower grade, more extensive Jersey Pit. Upwards of 150 tons per day of bornite-chalcopyrite bulk concentrate is produced, ranging 0.25% to 1.5% in molybdenum grade depending on the area mined."

Jan 1, 1980

By Steven Townend

Mining-related activities have been known to create a challenging operating environment for mining companies located in close proximity to communities. Issues such as noise, vibrations from mining operations, land use and emissions are often a concern for community residents. In order to develop good community relationships it is necessary to take a proactive approach. This paper documents this approach and also deals with the social implications for Vale associated with mining activities in the heart of the community of Copper Cliff, Ontario, Canada.

May 1, 2011

By Stuart McTavish

"Noranda's Goldstream mine is a 1,500 ton per day copper-zinc mine located 60 miles north of Revelstoke, B.C.The orebody which contains 3.69% Cu and 2.69% Zn was discovered in 1972. Construction of the mine and mill was completed in 1982 and start up was achieved in May 1983.This paper will describe the flowsheet and related equipment 1n the crusher and mill, in particular the dewatering section where two Larox pressure filters are used to dry the concentrates.INTRODUCTIONThe Goldstrean property is located 60 miles north of Revelstoke, B.C. in the Goldstream River Valley (Figure #1). It was discovered during the construction of a logging road in 1972. Exploratory drilling was initiated in 1975, and in 1976 a portal was collared to obtain underground data. Samples were taken from the underground workings for metallurgical bench tests and a pilot plant run.Due to economic conditions, the decision to go into production was delayed until 1980. Concentrator construction and underground development progressed simultaneously during 1981 and 1982, and were completed by the end of 1982. Start up of the concentrator was achieved on May 2, 1983.The ore typically contains about 40% sulphides, which are chalcopyrite 10%, sphaletite 6%, pyrrhotite 20%, and pyrite less than 5%. The sulphide minerals have a high degree of intergrowth. Most of the sphalerite occurs in micron sized grains which are embedded in the pyrrhotite and, to a lesser degree in the chalcopyrite. There is also some fine dissemination of the chalcopyrite in the pyrrhotite. The waste rock is made up of about 30% quartz, 20% guange silicates, and 10% carbonates. The ore has a specific gravity of 3.2 and a natural pH of 8.2."

Jan 1, 1985

By R. Jolicoeur, J. F. Jackson, M. A. Green

"The design, construction and commissioning of Kiena Gold Mines Limited's new mill was completed in 15 months ending in September 1984. Rated at 1250 tonnes per day the mill incorporates the latest innovative technology such as semi-autogenous grinding, carbon in pulp, pressure stripping and induction furnace refining. The mill is housed in a pre-engineered building with the leach tanks and thickeners located outdoors in spite of the intense winter cold. 1.0 INTRODUCTION AND HISTORYThe operations or Kiena Gold Mines Limited are located in Dubw1sson Township, approximately 10 Km west of Val d'Or, in the Abitibi region northwestern Quebec. Comprised of 59 mining claims covering 1214 hectares, a large portion of the mining property is overlain by the waters of Lac de Montigny. Sometime between 1911 and 1914 Barney Parker discovered gold in a shear zone on an island in Lac de Montigny that now bears his name. The first shaft the Parker Shaft, was sunk in 1936 from the island to a depth of 136 meters but owing to the known veins being of limited extent and the onset of the Second World War operations were terminated in 1940. In the early l960 1 s exploration drilling indicated an orebody of 4,500.000 tonnes at 6.3 grams of gold per tonne. A causeway was built to link the island to the mainland in 1963 and a new 3 compartment shaft was sunk to 403 metres. The orebody was further delineated and the ground conditions within the orebody and surrounds were evaluated.At the end of 1965 the property was placed on a care and maintenance basis as a mining operation would be marginal with gold selling at $35 per ounce."

Jan 1, 1986

By E. Shum, V. G. Papangelakis

"Attempts to reduce the energy requirements of water recovery in the process industries have resulted in the development of techniques to freeze and purify aqueous solutions that take advantage of local climatic conditions. Natural freezing is a technique by which aqueous solution is exposed to freezing air temperatures, resulting in the production of a layer of ice on the surface. As the ice layer tends to exclude solute, a concentrated solution is formed. However, due to dendritic ice growth along the advancing growth front, small quantities of solution are trapped within the ice, decreasing the purity of the water recovered. The ice produced can then be allowed to thaw in order to recover the water using low grade plant heat. As the more concentrated parts of the ice melt first, a purer ice remains. In this study, 0.5 molal magnesium sulfate solution was frozen under simulated natural freezing conditions at temperatures between –1 and –6°C. The ice produced was thawed at either room temperature or 50°C. Up to 40% of the water was recovered with a separation efficiency of above 95% when thawing at room temperature.INTRODUCTION Advances in refrigeration technology have made low-temperature separation processes increasingly appealing to an energy-conscious society. The latent heat of freezing of water is about seven times smaller than the latent heat of evaporation providing freezing with a strong thermodynamic advantage over the traditional evaporation-based processes. The result is the development of a wide variety of processes that fall under the term Freeze Concentration (FC), which describes a variety of techniques in which an aqueous solution is concentrated by the creation and subsequent removal of ice (Williams et al., 2015).FC processes exploit the freezing behaviour of aqueous solutions as dictated by their respective water-salt phase diagram. When, for example, a solution of magnesium sulfate is cooled to a temperature below its freezing point but above its eutectic temperature of –4.1?C (Figure 1) then, if the concentration of MgSO4 is less than the eutectic concentration (about 1.7 m), ice will form until the solution concentration reaches its equilibrium concentration at the given temperature on its phase diagram. If the concentration is greater than the eutectic concentration, MgSO4 solid will precipitate until the concentration reaches equilibrium. It is for this reason that ice can be selectively produced in FC processes (Randall & Nathoo, 2015)."

Jan 1, 2017

By Peter White

Mine Planning Shaft Collar Shaft Sinking Raises Ramp Underground Water Storage

May 1, 2009

By Donald J. Hallbom

"While pipeline hydrotransport is often the most economical way to transport large volumes of mineral concentrate, tailings, or fine ore slurry over long distances, it is in mountainous terrain that pipelining becomes particularly attractive. These areas are often remote, with limited existing infrastructure and few potential users willing to share in the cost of new infrastructure. The rugged terrain makes the construction of railways or roads suitable for haul trucks difficult and expensive. The elevation difference between the mine and the terminal means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. As a result, numerous pipelines have been built, or are being considered, in mountainous regions around the world including: Tasmania, New Guinea, China, Madagascar, the Rockies of North America, and the Andes of South America. However, there are technical difficulties that need to be overcome in the design and operation of mountain pipelines that do not affect pipelines on more level terrain. This presentation reviews some of these difficulties and methods used to overcome them.INTRODUCTIONPipeline transport of solid-liquid slurry (“hydrotransport”) is an important and cost-effective means of transporting large volumes of solids over long distances, especially from a single supplier to a single user (e.g., a concentrator to a port, a concentrator to a tailings dam, or a coal mine to a power plant). Pipelines are generally found to be more economically attractive than alternate transportation methods (e.g. trucking, rail, conveyors, shipping, or some combination) over the life of a project (Aude et al. 1974).Hydrotransport systems have been built in a variety of terrains, but it is in mountainous regions that pipelining becomes particularly attractive. These regions are often remote and generally do not have existing transportation infrastructure (roads, railways, navigable rivers). There are few potential users (e.g., farmers, other mines, forestry companies, etc.) who may be willing to share in the cost of new infrastructure. The rugged terrain makes the construction and maintenance of railways or all weather roads suitable for large haul trucks difficult and expensive. Mines tend to be higher than the receiving terminal (e.g. a port). This means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. Pipelines are easier to construct than roads and railroads in these areas for several reasons, including:"

Jan 1, 2006

By T. Gammatikopoulos, C. Gibson, M. Aghamirian

Lithium is an alkali metal found in brine deposits in the United States, Chile and Argentina, as well as in hard rock deposits in Australia and North America. In hard rock deposits, spodumene (LiAl(Si2O6)) is the major economic lithium bearing mineral. Spodumene is typically upgraded through a combination of dense media separation, flotation and magnetic separation. One of the major spodumene concentrate quality specifications is the iron oxide content because it will help determine if the concentrate is considered ceramic grade for use in ceramics and glass or chemical grade for use in lithium ion batteries. The rejection of iron bearing silicate minerals from artificial ore composites (high amphibole and low amphibole, high quartz/feldspar) from a hard-rock spodumene deposit was investigated using magnetic separation and flotation. The efficacy of Wet High Intensity Magnetic Separation (WHIMS) in iron rejection was found to be dependent on the mineralogy of the iron-bearing silicate minerals including modal distribution, liberation and association. When magnetic separation was conducted prior to flotation, the Fe2O3 grade in the final flotation spodumene concentrate was reduced from ~3% to ~1% Fe2O3 , and improved lithium recovery in flotation was observed. It was determined that it was most effective to conduct WHIMS on the flotation feed after scrubbing and de-sliming because this reduced the required magnetic field to recover iron-bearing minerals, likely because slime coating was greatly reduced. Flotation collector screening of four different collectors with varying rosin acid content demonstrated a potential increase in selective flotation of spodumene over some iron silicate minerals with decreasing rosin acid content in the fatty acid collector. However, due to marginal difference in flotation results with the various collectors tested, further testing is required to confirm the observations made and establish a hypothesis regarding the effect of rosin acid content.

Jan 1, 2017

By Dominic Fragomeni

"The mineral processing industry has had a long history of innovation that is recognized but not often celebrated. These include significant advances in mineral measurement, testing, comminution, mineral separation and process control technologies that have transformed mineral assemblages into ore.This presentation presents some of the major mineral processing innovations and the impact they have had on our industry. As we look to the future, it is critical that we innovate and change. We will explore some examples of the next developments and how they can be catalyzed in the face of risk management, lower metal price cycles, resource constraints, inertia and the challenge of short term value delivery."

Jan 1, 2017

By K. D. Hester

"1.0 INTRODUCTIONThe uranium industry started in Canada with the reopening of the gravity concentrator at Eldorado's Port Radium mine in the North West Territories in 1942. In 1948, uranium exploration and processing was opened to the private sector, and the Federal government offered special pricing incentives to the industry. Eldorado explored the Lake Athabaska deposits in northern Saskatchewan, and in 1953 opened the Beaverlodge mine. Other mines in the area soon followed. In 1953 also, the deposits in the Blind River - Elliot Lake area and in the Bancroft area of Ontario were discovered. Mines and mills were quickly developed in these areas.Canadian uranium production peaked at 15,900 short tons of U3O8 in 1959. In that year, uranium exports at $300,000,000 exceeded those of all other minerals in value. On October 1, 1959, Canadian uranium operations employed 13,900 people.Up to 1956, it was a seller's market. By 1958, world production of uranium was far ahead of requirements. Accordingly, in November of 1959, the USAEC announced it would not renew it's options for continued delivery of uranium from Canadian mines. This led to the ""stretchout"" of existing uranium contracts, and many mines were shut down (see Table 1) .In the early 1970's, a commercial uranium market seemed to be developing. In Ontario, at Elliot Lake and Bancroft, mines reopened. But competition was coming from the Athabaska basin of Saskatchewan. Currently it is these high grade, open pit deposits of northern Saskatchewan which are in the forefront of Canadian uranium developments. Canadian developments since 1942 reflect the political and market forces, as well as metallurgical progress and changes in environmental standards. This paper attempts to show these process changes in broad perspective."

Jan 1, 1987

By Wm Petruk

"The tungsten-bismuth-molybdenum deposit in southwestern New Brunswick occurs in greisenized and silicified tuffite * and feldspar porphyry in and adjacent to volcanic necks. The ore minerals occur as veins and veinlets and as disseminated grains in gangue. These minerals can be grouped into three assemblages. Assemblage 1 consists of oxides and phosphates of W, Ti, Fe, Nb, Sn, Ta and rare-earth elements, with the main minerals being deposited in the sequence wolframite, rutile, cassiterite. Assemblage 2 consists of arsenopyrite, molybdenite and bismuth, and assemblage 3 of sulphides with minor cassiterite and arsenopyrite. Sphalerite is the main sulphide mineral, but it contains minute inclusions of copper-tin- and indium-bearing minerals. Textural relations suggest that most of the elements can be recovered from this ore by conventional mineral beneficiation and extraction methods, but a variety of techniques must be employed. It is expected that the wolframite and molybdenite can be recovered satisfactorily, but poor recoveries are expected for bismuth and cassiterite. A sphalerite concentrate can be readily obtained by flotation, but it would contain a wide variety of elements. It is suggested that leaching be used to recover the bismuth and the elements in the sphalerite concentrate."

Jan 1, 1973

By E. W. Thorton

"This paper is intended to show that grinding media can effect flotation results, and in some instances the results are vastly different. I do not suggest that autogenous grinding is beneficial in the separation of all complex base metal ores, in fact I know of a case where autogenous grinding would be disastrous to any selective flotation. I do however contend that prospective flow sheets and reagent balances of any complex base metal ores should be tried with both types of grinding. I feel fortunate that the paper to be presented later in this meeting by Rene Klymouski will, I think, compliment and perhaps explain some of the results of my research.This paper will be in four parts. The first part deals with a literature survey on the subject. Surprisingly enough, very little information has been printed on the subject. The second part deals with results obtained in bench scale tests on an ore from Chester Mines Limited. It was in these tests that we realized that steel grinding was giving us serious problems. So bench scale tests are shown giving results with a stainless steel grind, a mild steel grind and a grind in a ceramic mill with ceramic billets.The third part of the paper deals with results obtained in the Mines Branch Pilot Plant, when again we ground the ore with three different types of grinding media. Incidentally, this has been the only pilot plant test made at the Mines Branch in which flotation products were made on both steel grinding and autogenous grinding on the same ore. The fourth part deals with two other New Brunswick ores and is intended to show that changing the grinding media effects ores other than that of Chester Mines Limited."

Jan 1, 1973

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher production rates and a resultant reduction in production cost. The Mining Innovation, Rehabilitation and Applied Research Corporation (MIRARCO) funded by the Canadian Mining Industry Research Organization (CAMIRO) has developed a methodology for safe rapid drift development within the underground metalliferrous mining industry in Canada According to industry survey, about 36% of drift development cycle time is spent on support installation. MIRARCO has developed a methodology for safe rapid drift development based on minimizing time spent on support installation. The methodology includes a critical review of the rockmass classification systems, examination of current support practices in the mining industry and civil tunneling, review of rapid drift development practice in South Africa, introduction of risk hazard procedures to account for material property variability and the development of a WIZARD as a quick decision-making tool for the implementation of the procedures. A comprehensive field data collection procedure was put in place and data collected from various mines to verify and calibrate the support selection rationale. The findings of the research programme resulted in the development of an improved rockmass classification system and showed that construction effects have drastic influence on support levels but is often not accounted for in assessing support levels. Stress effects and structurally controlled failures are the other important factors to take into account in rapid drift development. Three support classes were established for safe rapid drift development as No Systematic Support, Light Support and Strong Support. The support levels took into account cost, rate of installation and safety based on compatibility with ground characteristics. This paper describes the methodology for safe rapid drifting within the underground metalliferrous mining industry in Canada and highlights the key issues and major drivers behind their continued development at the Geomechanics Research Centre within MIRARCO.

May 1, 2004

By J. Jerome MacDonald, Stephen B. Flewelling

"In the base metals industry of today, operations required to continuously improve productivity and reduce unit production costs. Consistent with these goals is the improvement of the muck haulage cycle from open stopes with the No. 12 Mine.Existing haulage from open stopes occurs with LHD units experience at Brunswick indicates that LHD units have a higher unit cost per tonne mucked than loader-truck combinations when the haulage exceeds approximately 150 m.The reintroduction of open stoping at Brunswick made existing loader-truck combinations unsuitable. It was recognized that application of recent continuous loading technology could potentially result in significant unit cost savings and productivity increases.A review of the technology resulted in the testing of the Voest Alpine AL60 loader in the open stopes located on the 1000m Le vel. Testing began in January 1988 and finished in late November 1988. The test will provide experience as well as quantified production and maintenenace parameters f or the purpose of quantifying production unit costs and system productivity, ultimately resulting in a decision to further utilize or not utilize the loader as a primarymucking unit at Brunswick .INTRODUCTIONBrunswick Mining and Smelting Corporation Ltd. produces approximately 10500 tonnes per day from the No. 12Mine located 35 km southwest of Bathurst, New Brunswick Mining is the largest (single mine) producer of zinc in the world having mined over 52 million tonnes since 1964. Many years of production still remain with proven and probable reserves in excess of 90 million tonnes. Reserves grade at an average of 3.65% Pb. 8.99070 Zn, 99g/mt Ag and 0.32% Cu . The operation employs 1446 people with approximately 800underground including operations and maintenance staff.In the No. 12 Mine two major mining methods are presently utilized . The primary method is Mechanized Cut and Fill (MCF) accounting for approximately 6500 tonnes per day from four major areas. The remaining 4000 tonnes per day is produced from open stopes with the majority of 2800 tonnes per day being produced by the 1000 level.The 1000Level contains 30 million tonnes segmented into open stope blocks 30 m high, 15m and 30 m on strike , with a transverse width of 10m to 50 m (Fig. I). Stopes are organized on a primary secondary stope arrangement along strike. Primary stopes are undercut and overcut full size with the back fully cablebolted. All stope and lateral development is driven 4.0 m high. All stopes to date are flat bottom (Fig. 2). Primary stopes are filled with cemented rock- fill , secondaries with conventional rockfill, Haulage from the stopes is primarily with 8-yard LHD units ; mucking is approximately 50% conventional and 50% remote. Haul distance to date has averaged approximately 150m with current stope haul distances of approximately 300m. Haulage is presently to a small jaw crusher situated on the 1000 Level. From August 1989on, haulage will be to a set of ore passes feeding to a large gyratory crusher situated on the 1200 Level. Start up of the gyratory crusher corresponds to an increase in tonnage from 1000 Level to 4100 tonnes per day."

Jan 1, 1989

By Eduardo Nunez, Asim Tuzun, Dan Graffi, Glenn MacPherson

"In preparation for the milling of a new nickel and copper mine ore, Nickel Rim South, Xstrata’s Strathcona Mill is undertaking numerous process improvement projects. Within the grinding circuit, several projects are under development and an automated grinding control strategy, consistent with the operating objectives, was identified as a key requirement. The grinding strategy is to maximize the throughput (quantitative objective) while maintaining the cyclone overflow within specifications (qualitative objective).This paper describes the implementation of a robust grinding control strategy using the existing control system. The implemented controls maintain the cyclone overflow density at the desired target, while continually optimising the rod mill feed rate to allow maximum throughput. This approach has the added benefit of improving the stability of the rougher flotation circuit down stream of the grinding and improving energy efficiency of the rod and primary ball mills. This paper discusses the comparison of the before and after the implementation of results.INTRODUCTIONThe grinding process is a size reduction operation used in the mining industry to liberate the valuable minerals from the gangue. Grinding is one of the most important and expensive processes in a concentrator (Xi-song, 2007; Pomerleau 2000; Najim 1995), often accounting for around half of the total operating costs in base metal concentrators (Wills, 1990), which has led to a focus on development and implementation of control and optimisation strategies. The grinding process prepares the ore for the subsequent concentration step, which for sulphide base metal operations, is predominantly flotation. The performance of the concentration (flotation) is very much determined by the feed characteristics of the slurry coming from grinding. The valuable minerals recovery process in flotation is very much influenced by the grinding process and the liberation of the desired minerals from the gangue minerals (McIvor, 1991).The true objective of grinding is to obtain a proper liberation of the minerals as defined by a particle size distribution referenced typically by d80 (80% passing size of product). Besides achieving the desired mineral d80 size, it is clearly desirable to produce as narrow a size distribution as possible to squeeze the maximum amount of the mineral value into the highest recovery region (McIvor, 1991). This is an important criterion for the mill in economically optimizing the grade and recovery for the concentrate product. It is important not to over or under grind, while keeping the specific comminution energy as low as possible (Nunez, 2005) to achieve the target liberation. In other words, maintain an optimal throughput depending on the ore conditions to the capacity of the grinding mills, while providing the flotation process with a constant and narrow size distribution, at a cut size selected to meet the metallurgical requirements (Bascur, 1991)."

Jan 1, 2009

By D. Schleiss

Reduced access to knowledgeable workers is creating challenges for operations. We are doing more 4D Operations - dirty, dull, dangerous, and distant. Personnel costs in these environments are high, and it is not always possible to get the people where you need them. Integrated Operations is a strategy to integrate people, process, and technology for faster and better decision making. Adopting an integrated operations approach can help to relocate personnel, improve collaboration, and align objectives to deliver reduced costs and improved performance. In this paper, the authors will highlight the required infrastructure to enable an Integrated Operations platform. Key decision points for enabling this technology for both Greenfield projects and existing mines will be discussed. Furthermore, the benefits and improved return on investment that result from deployment of an Integrated Operations strategy will be presented.

Jan 1, 2014

By Peter Bourke, Marc van Olst, Seppo Ronkainen, Natalie Brown

"Since the early days of flotation, process technicians have known that the speed at which the froth is recovered over the lip of the cell has a very direct and consistent influence on the grade and recovery of the circuit. No plant would deny that, even to this day, one of the most important aspects of a process technician’s job is ensuring that the froth is moving at a desired and controlled speed over the lip. Unfortunately, process technicians cannot watch the froth throughout the entire shift, as there are always a lot of other tasks to do.A considerable amount of work has thus been done to develop a “system” that automatically measures the speed of the froth. This measurement would then be used in simple controllers to emulate the steps taken by the process technician in correcting deviations of the froth speed from its desired level. Many of the earlier attempts to measure speed were ineffective, as they were unable to cope with turbulence on the froth surface. The FrothMasterTM instrument makes use of machine vision technologies to measure the speed of the froth over the lip of a cell at a very high sampling rate. This instrument produces an extremely reliable and accurate measurement of the froth speed (as well as other parameters such as bubble size and froth stability). As we will show, the effectiveness of the speed measurement in controlling the performance of the plant is a testimony to its reliability.Three FrothMasterTM units have recently been installed on the Cadia Hills Gold Mine in New South Wales (Australia). The objectives of this installation were:To control the mass-recovery of two Tank Cells in series on the same level where differences in the hydrostatic head between the two cells result in the cells pulling inconsistently with respect to each other.Control of the concentrate grade (%Copper) from the first rougher.Reduction in the frother consumption in the rougher circuit by monitoring the froth speed.A simple controller was designed to react to disturbances in the same way that human operators react. This was done after consultation with the metallurgists and the process technicians at Cadia. The controller had two functions:Stabilisation: The stabilising controller made use of three manipulated variables (level, frother addition rate and aeration rate) to control the froth speed to a setpoint.Optimisation: The optimising controller adjusted the froth speed setpoint based on deviations of the grade (measured in real-time with an OSA) from a setpoint. The plant metallurgist adjusted the grade setpoint based on information about the ore."

Jan 1, 2001

By A. Tylczak, C. Norman, C. Shook, S. Loif

"There are a lot of good reasons to manage energy use at mining operations. Optimizing process energy use reduces operating costs. Tracking energy use can help identify unplanned process changes or malfunctioning equipment early, which allows problems to be corrected promptly.Sacré-Davey Engineering in Vancouver has performed over 50 Energy Management studies for various industries including: mining, pulp and paper, oil and gas, etc. Energy Management programs can be used to identify energy reduction opportunities, assess project feasibility, complete equipment selection trade-offs, as well as to monitor and manage energy costs. Benefits of energy management programs are reduced energy costs, reduced maintenance, and increased plant automation. Additionally, energy management can provide access to utility incentive funding and quantify savings which can greatly improve the return on investment of potential projects.Energy management studies are funded by many Utility programs across Canada. There are various programs available for existing plants energy audits, project feasibility studies, new plant design reviews and energy monitoring and targeting, etc. There are capital incentives available which can significantly reduce payback period.This paper discusses how energy management can be used to support mill/mine operations groups, maintenance programs, as well as expansion or green field projects. This paper will also provide an overview of Canadian Utility companies programs and how they can assist mining companies.IntroductionThere are a lot of good reasons to manage energy use at mining operations. Optimizing process energy use reduces operating costs. Tracking energy use can help identify unplanned process changes and identify malfunctioning equipment early, which allows problems to be corrected promptly."

Jan 1, 2015