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By I. G. Townsend, S. A. Buckley, C. I. House

"SummaryBritish Petroleum plc is developing a new gold recovery process known as coal gold agglomeration (CGA) for the recovery of gold from its ores. Liberated gold grains are recovered with high efficiency by adhering to agglomerates of coal and oil. The process is simple, can recover gold grains down to very fine sizes, avoids the large scale use of cyanide and provides the industry with an important new process option.A technical appraisal of the process has been performed on an extensive range of gold bearing materials. Ore types have been identified from which high gold recoveries can be achieved. A spreadsheet based computer program has been used to estimate the preliminary capital and operating costs of the process. Comparison with established gold production costs shows that the process costs of CGA, on the appropriate ore types, are potentially very attractive, which will enable economic treatment of lower grade ores than is currently possible using conventional cyanidation. Treatment of known placer deposits or gravity concentration plant tailings may be the most rapid means of demonstrating the process at a commercial scale prior to more widespread applications.1. INTRODUCTIONWestern world gold production for the 1980s has shown rapid growth sustained by a demand for gold at a favourable price (Fig. 1). Heap leaching and CIP/CIL operations have been responsible for the major part of new production during the 1970s and 1980s with present overall production costs averaging US$200/oz in Canada, USA and Australia and US$265/oz in South Africa [l]. A great deal of research and process development effort in the 1980s has been towards the treatment of refractory ores. Operating costs for the economic processing of these ore types by currently available routes are around US$300/oz [2]."

Jan 1, 1989

By C. M. Davidson, D. J. Drexler

"Sulphuric acid treated with hydrogen peroxide to destroy organic contaminants could conceivably show increased corrosivity toward carbon steel shipping and storage vessels, caused by the persistence of a peroxide residual. This paper describes work performed to determine the effect of 0-200ppm hydrogen peroxide on the corrosion of carbon steel by 93% and 98% sulphuric acid at room temperature (23ºC) and 50ºC.Steel electrodes were exposed to acid containing several peroxide levels (0. 45, iOO and 200 ppm) for up to two weeks. Specimens were removed at intervals and weight loss, open circuit potential, depth of metal loss and residual peroxide concentration recorded.Hydrogen peroxide decomposes considerably over two weeks in iron-contaminated sulphuric acid. initial peroxide concentrations > l00 ppm suppress corrosion, but the effect is lost when concentration decays below about 60 ppm. Sustained peroxide levels in the range below 60 ppm may increase corrosion rates. These phenomena are interpreted by analogy with anodic passivation."

Jan 1, 1987

"7.1. Glossary of the Platinum-Group Minerals7.1.1. IntroductionA glossary of the platinum-group minerals (POM) serves as a useful introduction to a chapter on their mineralogy. Earlier glossaries (Cabri, 1972, 1976) were prepared for different purposes and composed in a different manner. As for most mineralogical textbooks, from Dana's System of Mineralogy, 3rd Edition (1850) , to Fleischer's Glossary of Mineral Species (1980), this glossary is primarily a chemical classification, arranged here in two tables. Table 7.1 groups the mineralforming compounds of the six platinum-group elements (POE) according to their essential anion(s) or according to the nonPOE element in intermetallic compounds. Table 7.2 is a similar listing for the native metals and alloys of the POE. Both tables include unidentified POM considered to be bona fide new minerals requiring additional study for complete characterization and recognition (see Chapter 9*). Some information on the chemistry of the POM is given in the sections on X-ray data (7 .2) and ore microscopy (7 .3). Because the overwhelming majority of POM have been characterized by the electron microprobe, a more detailed account of representative analyses is given in Chapter 8**. The total POM listed in Tables 7.1 and 7.2 is about 100, after deleting some which would not qualify as discrete species if found today, but which are still recognized on historical grounds; e.g. iridosmine, osmiridium, platiniridium. Tables 7.1 and 7.2 also include 28 unnamed POM; included because they are considered to be probably new species (Cabri 1981 b). The referral scheme for unnamed minerals is the same as in Chapter 9. There are considerably more palladium minerals known than other POM; the proportion of total species (listed in Tables 7.1 and 7 .2) for the POE is: Pd 48%, Pt 21 o/o , Ru and Ir 9% each, Rh 8% and Os 5%. These proportions are in marked contrast to the estimated cosmic abundance, as compiled for average type C1 chondrite by Naldrett and Duke (1980): Pt 29%, Ru 20%, Pd, Ir and Os 15% each, and Rh 6%."

Jan 1, 1979

By Klaus Tietz, Hamish Adam, John Selby, Ian Glazier, Brian Sinfield

"Room-temperature tunable diode laser (TDL) analyzers are gaining in acceptance for highly critical safety monitoring applications in a variety of industries. This paper describes the testing, evaluation and deployment of a laser-based hydrogen cyanide monitoring system at the Campbell Complex of Goldcorp’s Red Lake Gold Mines in Balmertown, Ontario, Canada.A trial, single channel installation was followed by a staged multi-channel installation. Unexpected technical issues with the multi-channel installation were addressed and resolved.INTRODUCTIONLaser-based gas detection has several advantages over existing gas detection techniques (Ballangrud, 1993; Silver, 1992; Bomse, 1995; Table 1). For practical purposes, lasers generate light at a single wavelength. Room temperature tunable diode lasers (TDL) emit light in the near infrared (NIR) part of the electro-magnetic spectrum. Many gases of interest, including HCN, NH3 and others, absorb energy in the near infrared (NIR). Each gas has a unique absorption signature, or spectrum, made up of a large number of individual “absorption lines”. A TDL can be tuned to select a single absorption line of a target gas, which does not overlap with absorption lines from any other gases. Therefore, laser gas sensing is selective and does not suffer from interference from other gases. The single-wavelength nature of laser light also means that laser gas analysers have a linear response over a wide dynamic range.Tunable Diode Lasers (TDL) generate only a few mW of power. However, all this power is concentrated at one wavelength, the wavelength where gas absorption occurs, resulting in high signal-to-noise ratios and short response times, typically of about 1 or 2 seconds (Ballangrud, 1993). This also means that long path lengths can be used, enabling accurate measurements of very low concentrations, even with weakly absorbing gases. Tunable Diode Lasers provide all the advantages of other semiconductor devices: they are small, solid-state devices, operate at room temperature, and have long-term reliability (over 15 years). Currently, they can be obtained for any wavelength throughout the NIR (700nm to 2000nm). Because many gases absorb in the NIR, the technique is widely applicable."

Jan 1, 2011

By B. Tanda

A process has been developed at Curtin University whereby glycine is used in an alkaline environment to leach gold, silver and copper from their ores, concentrates, process intermediates and wastes. Copper mineralisation investigated includes various oxides, sulfides and native copper. The leach process utilises an oxidising environment such as oxygen. Glycine is a non-toxic, non-volatile, edible, low cost reagent which is produced in large industrial quantities for use in several industries. Glycine and its copper and precious metals complexes are stable over wide pH, Eh and temperature ranges. Other than losses in leach residues, the glycine is recovered and recycled for leaching. Iron dissolution is insignificant in the pregnant leach solution. Iron in pyrite remains unaffected, whereas iron associated with base metal sulfides (e.g. chalcopyrite and bornite) is converted to a readily filterable iron hydroxide. Efficient separation of copper by solvent extraction and conventional electrowinning has been shown to be feasible for a number of organic extractants, whereas gold and silver glycinates adsorb very well onto carbon allowing CIP/CIL/CIC (carbon-in-column) based processes. The process is ideal for ores containing acid-consuming gangue, concentrates with high arsenic or halide contents and for copper-gold ores with significant sulfide mineralisation. The process eliminates many of the problems associated with the processing of copper-gold-silver ores, such as elemental sulfur formation, silica gels, unwanted metal co-dissolution, and jarosite precipitation. The reagents used and process residues are much safer and environmentally benign than conventional process options. The processing technology can be applied to in-situ, heap and vat, or agitated tank leaching at temperatures ranging from ambient to below 100?C at atmospheric pressure and is currently being commercialised. This paper will focus on copper leaching and recovery and iron rejection from a chalcopyrite flotation concentrate.

Jan 1, 2016

By B. Goard

"IntroductionCemented backfill has been placed underground in slurry form in Inco Limited's Ontario Division mines since the early 196Os. The slurry was traditionally mixed on surface at between 65 and 70 wt% solids* and transported underground via gravity through a borehole-pipeline distribution system. This method of placement, while simple and dependable, has proven to be costly because of the large amounts of transport water involved.A significant quantity of the slimes buildup on mine levels is caused by the backfill water carrying cement and other fine material out of the stopes. The level cleanup and eventual pumping or hoisting of the slimes and water back to surface result in substantial indirect backfilling costs.The cement that remains in the stope is always overhydrated because of the high water cement ratios that exist. As a consequence, high concentrations of Portland cement must be added to the backfill to produce the fill strengths required for the different mining methods.Pouring backfill at these densities also demands extensive fill preparatory work in the stopes to withstand the hydraulic heads created by the slurried fill. This, along with the delays in pouring necessary to allow for water drainage, result in significant losses in productivity.These negative aspects of slurry placed fill has led Inco Limited to investigate several methods of transporting backfill underground via pipeline, at higher densities (i.e. 75 to 95 wt.% solids). Three separate transport methods are presently being experimented with by the Company's Mines Research Department. Each utilizes a different technique or form of flow transport, i.e. concrete pumping technology, high density slurry flow, and pneumatic conveying."

Jan 1, 1987

By Kazutoshi Haga, Batnasan Altansukh, Atsushi Shibayama

In this study, the dissolution behavior of copper and arsenic from five different copper concentrates containing 21-34.7 %wt. of Cu, 1.3-7.3 %wt. of As and 15.6-27.5 %wt. of Fe were investigated under high pressure oxidative leaching conditions. Leaching experiments were conducted using different leaching reagents such as ferric sulfate, sodium chloride, deionized water, sulfuric acid and ferric sulfate-sodium chloride mixture in order to compare the effectiveness of each on the dissolution of copper and arsenic from copper concentrates. The effects of ferric sulfate (0.1-1 mol/L), sodium chloride (0.1-0.5 mol/L) and leaching temperature (100-180C) were investigated under 1 MPa autoclave pressure , particle size >45 m, pulp density of 100 g/L, stirring speed of 750 rpm and leaching time of 60 min. Results showed that the most effective leaching reagents for the dissolution of copper are 0.34 M NaCl and a mixture of 0.1 M Fe2(SO4)3 - 0.34 M NaCl, in which As extraction did not exceed 7%. The copper concentration in the pregnant leach solution obtained after leaching using 0.1 M Fe2(SO4)3 - 0.34 M NaCl was 13-30 g/L, while the concentration of As and Fe were in a range between 0.3-1 g/L and 0.2-10 g/L at 160C. INTRODUCTION Copper sulfide minerals, such as chalcopyrite (CuFeS2), chalcocite (Cu2S) and covellite (CuS) are used for the production of copper in mining and metallurgical industries worldwide. The conventional pyrometallurgical processing followed by electrorefining is a common process for the production of high purity copper (Moskalyk, & Alfantazi, 2003; Padilla, Aracena, & Ruiz, 2012). However, the degradation of copper content and an increase in the amount of metal impurities, especially arsenic (As), antimony (Sb) and bismuth (Bi) in copper concentrates cause serious problems to the production of copper and environmental pollution (Basha, Selvi, Ramasamy, & Chellammal, 2008; Long, Peng, & Bradshaw, 2012). Hydrometallurgical processes are used to recover metals from refractory ores, concentrates and tailings by leaching (Long, Peng, & Bradshaw, 2012; Masloboev, Seleznev, Svetlov, & Makarov, 2018). During the last decades, hydrometallurgical processing for the recovery of copper from enargite-bearing copper ores and concentrates has been extensively investigated due to its relatively more environmentally benign and less capital costs than the conventional pyrometallurgical processes (Long, Peng, & Bradshaw, 2012; Masloboev, Seleznev, Svetlov, & Makarov, 2018; Choubey, Lee, Kim, & Kim 2018). However, several issues facing the hydrometallurgical processing are incomplete extraction of copper associated with the coprecipitation of iron compounds, difficult stabilization of toxic impurities and production of a contaminated copper product (Dreisinger, 2003; Safarzadeh, Moats, & Miller, 2014). Hence, a number of studies have been conducted on the selective dissolution of copper from copper ores and concentrates or selective removal of arsenic leaving a clean copper residue using various leaching reagents or lixiviants (Safarzadeh, Moats, & Miller, 2014; Mihajlovic, Strbac, Zivkovic, Kovacevic, & Stehernic, 2007; Tongamp, Takasaki, & Shibayama, 2009). More extensive studies on the selective extraction of copper from enargite- bearing copper ores and concentrates are much needed to improve copper recovery.

Jan 1, 2019

By Erwin L. Zodrow

"The neglect of including the toxic metal mercury in the list of escaping elements (Zodrow, CIM Bulletin, September 1982, pp. 138-140) was pointed out to the author in a private letter by J.E. Rehder, dated September 21, 1982. I welcome this opportunity to present my preliminary mercury research data based on coal investigations supported by N.S.E.R.C and the University College.As mercury is a volatile element and liquid at room temperature, special analytical techniques are required to determine concentrations in whole coal. In the investigation, the coal is analyzed by flameless atomic absorption with a lower detection limit of approximately 10 parts per billion, which, however, is a function of the ash contents of the coals (personal communication, J.L. Brooker, XRAL, 1981).Coal seams of the Sydney Coalfield studied so far include: the Point Aconi, a thin shaly coal, the Upper Bonar, an overrider of the Harbour seam, and the Harbour, Shoemaker and McAulay seams, all of which are shown in stratigraphic succession in Figure 1. The seams have been channel-sampled taking 15-cm coal intervals as one sample for analysis. One channel sample has been investigated from each of the seams listed (two channels were taken from the Point Aconi seam), resulting in 38 samples. Table 1 shows the results, which include mercury contents, ash and total sulphur per sample interval. Figure 2 is a frequency distribution of the 38 determinations."

Jan 1, 1982

By T. T. Chen, W. Petruk

The mineralogy of the feed, concentrates and tailings from the Heath Steele mill in New Brunswick was studied in detail to determine the liberation and recoveries of the major ore minerals, and to characterize the occurrence and distribution of the trace elements. The ore milled during August 1977 contained an average of 4.34 wt % Zn, 1.25 wt % Cu, 1.64 wt % Pb and 90 gr/ton Ag. The main trace elements in the ore are silver, cadmium, indium, cobalt, antimony, bismuth, arsenic, mercury, tin and gold. Silver is carried in solid solution in tetrahedrite-tennantlte, galena, Ag-Sb sulfosalts and Pb-Bi-Sb sulfosalts. Approximately half of the silver is recovered in the lead and copper concentrates and the remainder is lost in the tailings and Zn concentrate. As the major silver-bearing minerals also contain Sb and Bi, recovering silver by ore dressing would involve recovering elements that are troublesome in extraction metallurgy. Cadmium and most of the indium and mercury occur in solid solution in sphalerite and consequently are recovered in the zinc concentrate. Some indium is also recovered in the copper concentrate in a second unidentified indium-bearing mineral. Cobalt and arsenic occur principally in arsenopyrite, cobaltite, a Co-Fe sulfarsenide, pyrite and pyrrhotite, and follow these minerals into the tailings. Recovery of the valuable element cobalt, therefore, would involve recovering the environmentally hazardous element arsenic. Most of the tin and gold report to tailings. The ore was ground to about 80% minus 270 mesh. At this grind, 71 wt % of the sphalerite, 66 wt % of the chalcopyrite and 59 wt % of the galena were liberated. Recoveries of free sphalerite, free chalcopyrite and free galena in the Zn, Cu and Pb concentrates were 85 wt %, 76 wt % and 80 wt %, respectively; recoveries of unliberated sphalerite, unliberated chalcopyrite and unliberated galena in the respective Zn, Cu and Pb concentrates were 48 wt %, 5 wt % and 7 wt %. Some of the unliberated sphalerite and chalcopyrite grains in the tailings are large and would have been liberated at a finer grind.

Jan 1, 1980

By Sean Dessureault

Information technology (IT) initiatives in the past have tended to be sold on their ability to maximize resource output and return on capital by using assets more effectively and efficiently. Many IT projects fail, not delivering return on their investment. This is known in the IT industry as the ?productivity paradox,? where increasing investments in IT do not result in comparable increases in productivity. Experiences and studies of most business sectors reveal that this paradox is rooted in the false assumption that more IT spending automatically results in financial benefit, whereas the true source of benefits is in how effectively IT is used. Most business sectors have accepted that the reengineering of processes is required to gain the full benefits promised of IT. A mining operation has organizational processes similar to most business sectors but unique operational processes. The lessons of changing business practice in more common business processes such as inventory control and customer-supplier relationships can be adequately transposed into a mine. The unique operational processes in mines, in turn require unique redesign efforts. Several enabling information technology opportunities have recently become available, such as more integrated mine production management systems and tactical manger training simulators. This paper reviews the latest IT products and ou lines the processes and kinds of change that will be required in order to benefit from these new investment options.

May 1, 2002

By R. Grimard, M. Gamache, L. -P. Bigras, P. Cohen

This paper describes a real-time fleet management system for an undergroun mine. Dispatching, routing and scheduling are handled simultaneously, taking into account the mine status, operational constraints and vehicle location information. Each assignment decision takes into account the traffic on the road segments of the mine network, whether road segments are bi-directional or uni-directional, and ensures that each LHD (load-haul-dump) vehicle arrives at loading and dumping points with the correct orientation. Such a system can be used either as a simulation tool for strategic planning or as a real-time managing and optimizing system for operations. In the simulation mode, the system can accurately estimate the impact on productivity of decisions such as the development of waiting areas (bays, sidings), or the addition (elimination) of vehicles to the fleet in operation. When used for real-time dispatching, routing and scheduling of vehicles, the system can optimize production with respect to various assignment criteria such as cycle-time minimization or deviation from a target production plan.

Jan 1, 2004

By Lewis Martin

Whereas many researchers and mine engineers have conducted tests using different types of grout, grout ratios, and physical modifications of the cable to determine cable bolt load characteristics, few studies have been conducted on cables fitted with internal instruments. Those studies that have been done have concentrated on cable behavior averaged over significant cable lengths. Researchers at the Spokane Research Laboratory (SRL) of the National Institute for Occupational Safety and Health in Spokane, WA, are investigating the physical properties of cable bolts by replacing the conventional king wire with a modified king wire on which strain gauges have been installed . This paper documents test results on these modified cable bolts. Three tests were conducted at SRL on 1.83-m-long cables grouted into two 0.91-m-long pull-tube assemblies. Load along the cable was monitored with 20 strain gauges installed along the length of the cable. The instrumented cable bolt provided reproducible point measurements of cable load as opposed to load measurements averaged over significant cable lengths. Such point measurements can assist in interpreting the influence of cable confinement, grout quality, rock mass stiffness, and other factors. The instrumented cable bolt is a practical field and research tool because it can predict point loading along the cable and thereby allow interpolation of maximum possible loads on a cable.

May 1, 2002

By D. W. Hendriks, C. Daoust, K. V. Konigsmann

"The concentrator of Mattagami Lake Mines Limited commenced operation in 1963. It had been designed with instrumentation proven at that time. New control techniques were added in subsequent years.An on-stream X-ray analyser was installed in 1968. It provided circuit analyses for six years without the aid of a computer. In late 1974, control of the flotation circuit by computer was incorporated into the system. Flotation efficiency improved considerably, zinc"" recovery increased by one percentage point and concentrate grade by four-tenths of a percentage point. Reagent costs decreased modestly through reduction of copper sulphate consumption."

Jan 1, 1976

By Svato Prochazka

Content: ? commonly used drive systems ? drive system efficiency ? introduction to SR technology ? SR drive system advantages Commonly Used Feeder Drives Technologies ? VFD + induction motor ? hydraulic drive + hydraulic motor SR drive + SR motor

May 1, 2010

By Simon W. Houlding

The mining community is geographically remote and widely dispersed. There is a growing requirement for formalized professional development of members by professional associations, and increasing recognition of the advantages of continuing education and training by both individuals and corporations. Working against these trends are the increasing expense and time commitments required for attendance at conventional courses and workshops. The result is a perceived need for a readily accessible source of continuing education and technical reference on the Internet. The design constraints for an Internet model for professional development include: ? browser compatibility, with any time, any place, any pace accessibility; ? a content presentation model with low bandwidth requirements, appropriate interactivity for examples, tools and reviews, and viewer performance monitoring capabilities; ? formal accreditation of content, presentation and process so that viewer achievements may be formalized in terms of widely recognized Continuing Education Units; ? availability of tools for conversion of source material to the presentation format with minimal effort. A model that meets the design constraints is presented and illustrated by examples from an existing Internet site for continuing education in mining.

May 1, 2002

By L. C. St. Arnaud

"Open pit mines can produce large disturbances within regional hydrogeologic systems. The degree of disturbance and the consequences on the local environment depend on the size of the pit and on the physical setting of the mine. Comparisons and contrasts are presented for three Noranda base metal open pit mine sites.The Brunswick Mining and Smelting No 6 open pit has a surface area of 11 ha and a depth of 185 m. It is located within complexly deformed schists and meta-volcanic rocks. The massive sulphide and iron formations visible along the north and southwest walls of the pit generate acid drainage. Mining ceased in 1983, and the pit is presently being filled with waste rock and neutralized drainage water. Water balance calculations estimated a total fill up time of sixteen years. As the water level rises, leakage to groundwater could take place across a fault zone intersecting the pit.The Mattabi Mines F-Group pit has a surface area of approximately 3 ha and a depth of 50 m and is also set in meta-volcanic rocks and acid generating iron formations. Production at this site ceased in 1982, and the low pH pit water is neutralized and pumped into a nearby lake at least every five years. Major water inflows are from precipitation and groundwater. Groundwater mounds within adjacent high land surrounding the pit provide a natural hydraulic barrier to groundwater flow, except for the southeast side. As a consequence, the pit water elevation is being kept below the elevation of the nearby creek in which some of the pit water could drain.The Bell Copper open pit covers an area of 40 ha and is 270 m deep. With present ore reserves, the mine might be in operation until 1992. The geology around the pit consists of andesitic tufts, siltstones and shales, and the acid generation potential of the rock is relatively low. A recent hydrogeological study estimated fill up time by precipitation and groundwater to be in the order of 260 years.With increasingly more stringent requirements for mine closure, it is anticipated that more detailed hydrological and hydrogeological studies of open pits will be required to determine post-closure environmental impacts and the suitability of open pits for mine waste disposal."

Jan 1, 1990

By Janis A. Shandro

The mining sector is a major economic driver for Canadian, and British Columbian communities. In parallel strong commitments have been made by industry to the well-being and sustainability of associated communities. However, these dimensions are the least understood. Especially lacking are focused regional investigations that compare the well-being and sustainability of communities dependent on different resources sectors. It is hypothesized that this type of comparative analysis will help to foster a greater understanding of what makes a resource or mining community healthy and sustainable. This paper describes research that examined community-level indicators associated with well-being (e.g. education, income and employment) and sustainability (e.g. economic diversity). The indicators were derived from Canadian Census data for 31 British Columbia resource-based communities (with a focus on mining) during a period of time (1991 to 2001) when resource sectors experienced an economic downturn. Our findings identify that during this decade, mining communities differed significantly from other resource-based communities, and comparative analysis of census derived indictors illuminate challenges that mining communities in British Columbia face with respect to wellbeing and sustainability (such as economic diversity, unemployment, and population loss). To contribute to the mining sector?s efforts towards meeting their commitments to communities, this paper concludes by proposing strategic opportunities aimed at the enhancement of mining community sustainability for policy-makers, communities, and the mining industry to consider.

May 1, 2011

By Laura Mottola

Process Design and Change Management for Successful Deployment of Technology in Mining Over the last 30 years Canada has been successful in developing but not deploying hardrockmining automation. Our opinion is that the current lack of R&D investment and implementation capacity places Canada at risk as a future global mining leader A white elephant A burdensome possession; creating more trouble than it is worth. White (albino) elephants were regarded as holy in ancient times in Thailand and other Asian countries. Keeping a white elephant was a very expensive undertaking, since the owner had to provide the elephant with special food and provide access for people who wanted to worship it. If a Thai King became dissatisfied with a subordinate, he would give him a white elephant. The gift would, in most cases, ruin the recipient.

May 1, 2010

By A. Tylczak, C. Shook, A. Doogan-Smith, S. Loif, B. Hilscher, P. Nayak

"This paper discusses how to effectively conduct energy efficiency studies during the design of new mineral processing plants and plant expansions. Energy management studies for new plants are ideally conducted as part of the feasibility study, but can also be done at the detailed design stage prior to the purchasing of equipment. Energy management engineers work as part of the mineral processing plant design team.Such studies usually result in energy savings of approximately 3-8% of the predicted plant’s energy consumption and energy demand. Potential cost savings can be significant. A variety of mineral processing systems – crushing/grinding, pumping, materials handling, fans/blowers, compressed air, and others – are assessed within this study.Energy Management Information System (EMIS) studies can also be performed for the new plant or plant expansion, as an independent study. EMIS can be incorporated into the electrical and controls design of the plant.Most Canadian Utility companies fund new plant design studies and provide financial incentives based on the predicted energy savings and incremental cost of the more energy-efficient design. A new plant energy efficiency study improves the potential for energy reduction because only the incremental equipment cost is included in the project return-on-investment calculation. After the design and construction phases, energy efficiency projects must justify the entire cost of the upgrade, which is significantly higher than the incremental cost alone.This paper outlines the major steps of a new plant/plant expansion energy efficiency study, the available utility company incentives, and the areas yielding the largest potential energy savings.IntroductionThis paper discusses energy efficiency studies and energy management systems with regards to mining operations. Energy management refers to the systems of monitoring, analyzing, and optimizing energy usage within a facility. It includes energy efficiency optimization of the initial plant design as well as the implementation of an Energy Management System (EnMS) and Energy Management Information System (EMIS) for optimizing energy usage over the lifetime of the facility. An EnMS is the organizational framework and procedures for managing energy use; an EMIS is the system of monitoring, reporting, and tracking process energy use against targets."

Jan 1, 2016

By André Pomerleau, Michel Grégoire, René del Villar

"The operation of industrial flotation columns requires the control of at least two variables, the interface position and the bias rate, by manipulation of some appropriate operating variables. Problems arise due to the reliability of existing methods of measuring the bias (i.e bias = tailings water - feed water), a situation which has often forced the industry to disregard this control loop. Moreover, when using such a measuring approach, the identification of the process dynamics is impossible. A second problem arises from the possible interaction between both control loops that might call for the use of a more complex multivariable control strategy.Recent work done at Lava1 University has demonstrated the feasibility of an independent sensor for bias, which models the relation between the conductivity profile across the interface and the bias value using a neural network algorithm. A 250 cm height, 5.25 cm diameter Plexiglas laboratory column was equipped with a series of conductivity electrodes in its uppermost part (across the interface) to measure both interface position and bias rate. Using such equipment, the flotation column dynamics were identified. The results thus obtained permitted the design and implementation of a distributed PI control strategy, where bias was associated to wash water rate and froth depth to tails rate. Both PI controllers were tuned using a frequency-response tuning method. Results of both identification and process control are presented and discussed.INTRODUCTIONFlotation columns are used for the separation of valuable minerals from a carrier gangue. Typically, this device is a tall (9 to 14 m height) cylinder (1 to 3 m in diameter) although other cross sectional shapes are also used. Finely ground ore is fed as a pulp at about 2 m from the top of the column, and pressurized air is introduced through a sparger at the bottom. If the pulp has been properly conditioned with adequate chemical reagents (collectors and modifiers), the valuable mineral particles falling by gravity will attach themselves to the rising air bubbles, and the air-particle aggregates will rise to the top of the column where they overflow as a stream called the concentrate. The gangue particles,, that do not attach to the air bubbles, fall down the column being withdrawn at its bottom in a stream called the tails.A particular characteristic of flotation columns is the addition of a fine spray of water at the top. As the water flows down through the froth zone, it washes out the entrained gangue particles from the mineralized bubbles, thus improving the quality of the concentrate recovered at the top. As a result of its cleaning action, this water stream is called the wash water and the upper zone, the cleaning zone. In order to ensure a downward flow of wash water, a proper water balance must be kept in the froth zone, otherwise the water added at the top might shortcircuit to the concentrate without performing any cleaning action. This net downward flow of water inside the froth zone is called the bias and represents an important operating variable of a flotation column."

Jan 1, 1999