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By N. Kacira

"Canada's largest known chromite deposit occurs in a layered intrusion in the Bird River area of Manitoba. However, numerically most of the chromite occurrences are in the Appalachians. Few, apparently minor, occurrences are also known in the Cordillera.In the Appalachians, chromite occurs as lenses and pods in dunite; they are of ""podiform"" type. The individual concentrations vary in size from a few pounds to tens of thousands of tons. Locally, chromite concentrations form discontinuous zones extending several hundred feet along strike and presumably down dip, therefore resembling boudinaged layers. Chromite layering and lineation are commonly concordant to those of the host rocks.The Appalachian chromite occurrences are thought to have been formed by fractional crystallization and perhaps also by liquid immiscibility. Their present shape and distribution are largely the result of deformation mostly prior to complete solidification of their host rocks. Therefore, the attitude of layering, foliation, lineation and other features related to deformation provide valuable guides in predicting the probable distribution of chromite, and hence are helpful in exploration.Chromites fulfilling the requirements for metallurgical, refractory and chemical grades occur in the Appalachians. Although the Appalachian deposits are similar in size and grade to some of the chromite deposits being mined elsewhere, they are unlikely to be economic, at present, in the higher wage Canadian environment. However, in case of shortages in chromite ore supply which may result, among other reasons, from increasing tendency to further processing in the producing countries, the Appalachian occurrences may become sources of ore. Such eventual shortages combined with relative abundance of electricity in Canada and recent innovations in oxide ore reduction technology may hasten the time when ferrochrome manufacture based on local chromite sources becomes economically viable."

Jan 1, 1982

By J. E. McMenamin, R. B. Hall

"With the emphasis in the past decade on larger and more efficient equipment for open-pit operations, the Normandie mine of the Asbestos Corporation has followed the trend, switching from the smaller type of percussion drills to down-the-hole rigs. One 5 Y2 -in. percussion drill is still in use, but is limited to a ""smooth blasting"" role or to the control of the slope on final benches.In keeping with the times, an attempt was made to eliminate, as much as possible, the use of high explosives and to maximize the percentage of ammonium nitrate -fuel oil mixture. As the concentration of ground water increased with increased mining depths, small pumps were initially employed for the dewatering of boreholes. This proved unsuccessful, and a hole-blowing rig was built and a conversion to plastic liners made. The acquisition of a bulk-mix AN-FO truck has permitted the changeover from an AN premix to an ammonium nitrate prill -fuel oil combination at the borehole."

Jan 1, 1966

By J. E. Gill

"THE YEAR 1959 appeared to be a good one in which to attempt a summary of progress in the location and study of sulphide deposits in Canada because a temporary surplus of metals caused prices to fall and many geologists who had been working like beavers were suddenly not so hard pressed. So it was •decided to arrange a Symposium. The response to the call for contributions was excellent and the result is the interesting collection of papers that follow.Activity in the search for massive sulphide deposits has never been as intense as in Canada since 1954. That was the year when the airborne electro-magnetometer first became generally available on a contract basis. These instruments work best on massive sulphide bodies, as do most of the ground electrical survey devices, so much of the new information relates to these. It was decided, therefore, to focus attention in the preparation of symposium papers on such masses. This served also to keep the survey within reasonable limits."

Jan 1, 1960

By Claude Hubert, Alex C. Brown, Michel Richard, Rejean Sirois

"The Pierre Beauchemin gold deposit, situated 15 km NW of Rouyn-Noranda, produces an average of 1050 tonnes of ore a day. Reserves are 1.2 Mt grading 5.6 g/t Au. The deposit, located in a shear zone within the Flavrianpluton, in the Blake River Group, is hosted by four major rock types: meta-trondhjemite, meta-tonalite, hybrid rocks and meta-diorite (the prefu; ""meta-"" is omitted thereafter). The trondhjemite, tonalite, and metamorphic hybrid rocks are spatially distributed as a series of sub-horizontal tabular sills that form a genetically related group. Early fractures that permitted either the emplacement of pre-diorite felsic dikes or the formation of a visible alteration caused by early fluid circulation might have been developed in response to initial strain created during regional deformation. These fractures were precursors to the emplacement of diorite and the development of major shear planes. Sub-horizontal north-trending en échelon diorite lenses are observed at the mine. Together, these diorite lenses constitute larger scale diorite zones which are observed at the scale of the pluton. The diorite zones are interpreted as evidence of an episode of sub-vertical extension sustained by the layered trondhjemite, tonalite and hybrid system. The anisotropy created by the less competent sub-horizontal en échelon diorite was an important factor. In shear zone development and subsequent mineralization. The tonalite and diorite accommodated further defomation and developed the main N030°/40° ESE shears along with the spatially associated N060°/50°-60° SSE, and the N000°/10°-40° E shear zones. The N000° shears are interpreted as refracted or deflected equivalents of the N030° shears. The combined shears compose the Eldrich shear system which trends approximately N030°/40° ESE and has had a general reverse movement with a minor sinistral component.Gold mineralization occurs in all four major rock types as en échelon sigmoidal shaped lenses associated with the major N030° deformation system. The distribution of ore lenses can be divided into two categories: The first category occupies sub-horizontal diorite zones. The lenses trend N-S, dip 100 40° E, and are associated with shear zones, sub-horizontal fractures or tonalite-diorite contact planes. The second category of lenses is found in felsic granitic rocks; the lenses trend either N0300!40°ESE or N060°/50°-60° SSE. Local hydraulic breccia zones are observed near ore zones occupying felsic granitic rocks. These breccias may have resulted from high fluid pressures brought upon by confinement as a result of impermeable zones in an anisotropic tonalite-diorite system."

Jan 1, 1990

By Minghao Hu, Hongbo Zhao, Jun Wang, Wenqing Qin, Rui Liao, Central South University

"In the present work, X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS) analysis and electrochemical analysis were carried out to investigate the intermediate species and electrochemical dissolution process of chalcopyrite in the presence of sulfur and iron oxidizing microorganisms. For bioleaching of chalcopyrite by the sulfur oxidizing microorganism Acidithiobacillus caldus, the redox potential was always lower than the appropriate value and chalcopyrite was mainly directly oxidized to polysulfide (Sn 2-), thus resulting in low copper extraction. As for bioleaching of chalcopyrite by the iron oxidizing microorganism Leptospirillum ferriphilum, chalcopyrite was mainly directly oxidized to polysulfide at the initial stage where redox potential was lower than the appropriate value and resulted in low dissolution rate. At the middle stage where redox potential was appropriate (about 350–480 mV vs. Ag/AgCl), chalcopyrite was mainly transformed to intermediate species of Cu2S rather than polysulfide, thus resulting in high dissolution rate. At the later stage where redox potential was higher than the appropriate value, chalcopyrite was mainly directly oxidized to polysulfide which caused the later passivation of chalcopyrite. Finally, a model of electrochemical dissolution process of chalcopyrite in the presence of sulfur and iron oxidizing microorganisms was provided.INTRODUCTIONBiohydrometallurgy is considered as one promising mineral processing technique in processing low grade ores due to the advantages of simplicity, low cost and eco-friendly. Chalcopyrite (CuFeS2) is the most abundant copper-bearing resource, accounting for appropriately 70% of the known reserves in the world, while is recalcitrant to bio-hydrometallurgy mainly due to the coated passivation layer (Klauber, 2008; Li, Kawashima, Li, Chandra, & Gerson, 2013). However, the detailed dissolution and passivation mechanisms of chalcopyrite bioleaching are still uncertain. The microorganisms assisting chalcopyrite dissolution can be mainly classified into three types, including mesophilic microorganisms (e.g., Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans), moderately thermophilic microorganisms (e.g., Acidithiobacillus caldus, Sulfobacillus thermosulfidooxidans and Leptospirillum ferriphilum), and extremely thermophilic microorganisms (e.g., Metallosphaera sedula, Sulfolobus sp., Acidianus sp., and Sulfurcoccus mirabilis). Moderately thermophilic microorganisms have a better prospect in the future industrial application of chalcopyrite bio-hydrometallurgy (Olson, Brierley, & Brierley, 2003; Rohwerder, Gehrke, Kinzler, & Sand, 2003). Hence, investigating the detailed dissolution and passivation mechanisms of chalcopyrite bioleaching by moderately thermophilic microorganisms is of important significance, which will provide essential information for promoting chalcopyrite bioleaching by moderately thermophilic microorganisms in laboratory or industrial plant."

Jan 1, 2016

"Dry crushing trials at pilot scale have shown that the IMPTEC Super-fine Crusher has the capacity to generate ultra-fine products from hard mineral assemblages presenting at either coarse or fine feed sizes. The super-fine crusher was introduced at the 27th International Mineral Processing Congress in Santiago Chile, with results from a range of duties, which demonstrated the crusher’s potentially expansive operating scope. This paper focuses on current preparations to progress the technology from pilot scale to commercial scale within a concrete production plant, where lead blast furnace slag will be crushed to ultrafine sizes to generate an active silica product for use as a supplementary cementitious material, which can replace Ordinary Portland Cement. A key objective of the operation is to demonstrate an economical route to reducing the cost of concrete production, improving concrete quality and reducing greenhouse gas emissions. The paper also highlights the potentially key contribution super-fine crushing can make to the long-term viability of iron ore beneficiation by simplifying comminution flow-sheets and reducing operating costs. There is every indication that the technology has the potential to feature universally in metalliferous and industrial mineral flow-sheets. INTRODUCTIONToday’s IMPTEC super-fine crusher is the successful end product of development work over 19 years and is the third particle size reduction device conceived, built and tested over that time. The concept evolved as engineering design progressively developed a mechanism capable of harnessing a highly efficient combination of fundamental particle breakage mechanisms. Early development trials at pilot scale indicated that super-fine crushing had the potential to establish a wet or dry, media free, low energy route to ultra- fine products from hard mineral assemblages. Having achieved some impressive results from open circuit pilot tests on fly ash and granulated blast furnace slag it became clear that the cement industry may well provide opportunities to apply the technology commercially. Following expressions of interest from local cement and concrete plant operators, IMPTEC negotiated an agreement to undertake commercial trials with a SFC 350 super-fine crusher installed on site at a concrete supply plant in South Australia. Super-fine crushing scope was recently expanded following further expressions of interest from research groups involved in the processing of iron ores. Pilot trials are progressing in these areas."

Jan 1, 2016

By W. Yang, R. Rajasingam, K. Mohanarangam

"Copper Electrowinning (EW) is a complex electrochemical process that involves the production of LME grade copper from copper rich electrolyte. The process involves the deposition of the copper ions onto the cathode from copper rich electrolyte with the production of oxygen bubbles at the anode. The process setups up a complex flow pattern within the cell as it is subjected to varying density gradients due to the deposition process along with oxygen bubble driven flow. It is a necessity to understand and quantify the flow behaviour within these cells in order to maintain the production of highest grade copper. In fact, the oxygen bubbles originating from the process is responsible for the generation of acid mist which is a designated as a carcinogen a major health hazard around EW tank houses. Hydrodynamic assessment of the process has so far been restricted to simple mass balances and some limited numerical modelling. All the models are based on assumed boundary conditions which has not so far been verified by any real-time physical measurement. This apparent gap has led to models which could not be directly used to track process changes or troubleshoot problems in EW tank houses. In order to address this gap, CSIRO has established a full size (width and height) transparent cell capable of simulating plant operating conditions (across the range currently used). With the use of sophisticated diagnostic analytical tools and measurement techniques it was possible to study all the operating variables (current density, flow rate, temperature, etc.) independently and their effect of bubble size, bubble velocity, gas hold-up as well as acid mist generation and its size. In order to address safety concerns in tank houses around acid mist early results outlining the factors contributing to its generation as well as the effect of various barriers to mitigate acid mist is outlined below.INTRODUCTIONA significant part of today’s copper production is through hydrometallurgical route which predominantly involves leaching, Solvent eXtraction (SX) followed by ElectroWinning (EW). Producing copper using this approach have shown to be environmentally friendly (Dresher, 2001) compared to the traditional smelting process. EW is the final step in the production of LME grade copper using the hydrometallurgy route. The electro-chemical process involves the use of a lead anode (Pb-Sn-Ca) and a stainless steel cathode to produce copper sheets using the copper rich electrolyte from the SX process and with the applications of direct current to the electrodes. This electro-chemical reaction results in the deposition of copper ions on the cathode with oxygen released from the anode as a by-product. Hydrodynamically, the oxygen bubbles create a bubble driven flow within the EW tanks with the surrounding electrolyte. A direct result of this could be seen from the quality of the copper deposited on the cathode. Most of the copper plates produced from the traditional tank houses have a rough texture at its bottom one-third while the top two-thirds have a smooth finish with a finer grain structure."

Jan 1, 2016

By Z. D. Hora

Traditionally, industrial minerals in British Columbia comprise about 10 per cent of the combined value of mineral, coal, petroleum and natural gas production. Over the years a wide variety of industrial minerals have been produced in British Columbia, often with a different level of marketing success. For some products such as building stone, common brick or expanded shale, once strong demand gradually disappeared; for others such as asbestos and barite, new discoveries or new industrial activities created demand and new markets. For yet other minerals such as fluorite, talc and perlite, wider use has been prevented by the small size, poor quality or remote locations of the deposits. Bentonite (1926 to 1944-as a by-product from coal mines) Building stone (intermittently since the mid-1800s) Chromite (1918 and 1929) Over the past years, the list of industrial minerals produced has been expanded to include several new commodities: glassgrade silica sand, magnesite, pumice and silica for ferrosilicon and silicon carbide manufacture.

Jan 1, 1984

By David Weiss

There is significant interest in magnesium alloy castings because of their low density and high strength-to-weight ratio. Lightweight, structural materials are in demand for aerospace components, hand tools, electronics enclosures and have found increased use in automobiles. Increased use of magnesium will depend on the resolution of a number of materials issues and development of more robust and economical casting processes. Most magnesium components are produced via high-pressure die-casting. High levels of porosity generally prevent die-castings from being used for structural applications. Structural castings are usually produced using sand casting, a relatively expensive casting process. Some work has been done on development of lower cost structural casting processes, such as lost foam casting, permanent mold casting or low-pressure casting. New programs are also emphasizing improvements to the die casting process. Research and cost reduction needs are discussed with respect to current programs and future components.

Jan 1, 2006

By G. J. Reid, D. H. Stewart

"A diversity of structures and rock types in the Aft on pit has resulted in the occurrence of several different types of wall failure. Delivery of ore to the mill has not been affected and safety has not been compromised thanks to effective remedial 1V0rk and to a system of structural mapping, back analyses of failures, groundwater monitoring, and simple movement monitoring. Remedial measures have included artificial support, dewatering (including vacuum-assisted drainage), flattening of slopes and temporary buttressing. This paper describes six different wall failures at Afton and highlights the features of each. Examples given include rates of movement, extent and direction of movement, and piezometric responses. The practical, low-cost monitoring system was sufficient in one case to allow the prediction of date of failure. IntroductionThe Afton copper deposit is located 13 km west of Karnloops, British Columbia and has been mined for nine years out o f an expected eleven-year life. Open pit mining has reached 700 feet below sur face and is designed to proceed to 970 feet below surface by the time the pit is completed. The excavation is in a structurally and lithologically complex environment. Inevitably, some wall failures have occurred but these have been limited to small, manageable failures which have not compromised production or safety. To handle the failures it has been necessary to understand their nature. Of prim e concern has been the rate s of movement, but displacement vectors and hydrology have been monitored as well. The monitoring system is based on EDM surveys and on wire extensometers and plates set across cracks. Water levels have been read in standpipe piezometers. At Afton the emphasis has been on simple, practical, and inexpensive monitoring and because rock type s and structures play such a major role in any failure, detailed geologic al mapping is carried out."

Jan 1, 1988

By A Frydrychewicz, J. Mirza, J. Lipkowski

The objective of this work was to understand the mechanisms of action of additives, such as thiourea, that enhance gold leaching in thiosulfate solution. The leaching reaction and surface passivation were investigated using linear sweep voltammetry. Leaching currents were determined using analysis of current-potential curves and the mixed potential theory. The gold-electrolyte interface was further characterized with surface enhanced Raman spectroscopy. The results show how thiourea prevents formation of oxysulfur compounds, which passivate the gold surface. Other molecules such as 3- m ercaptopropionic acid and L-cysteine were also studied as possible additives to prevent passive layer formation.

Jan 1, 2011

By G. P. Demopoulos

"The recovery and separation of platinum-group metals (PGM) from primary and secondary materials currently attracts a lot of interest due to the high value of the metals and their increasing demand for high-tech applications. Thus, the traditional refining processes are gradually replaced by newer more efficient separation techniques such as solvent extraction and ion exchange. In this paper the classical and modern refining techniques are reviewed and the pertinent solution chemistry dictating proper processing strategies in each case is discussed. The technological advantages of the modern separation methods are emphasized and reference to the recovery of PGM from primary as well as secondary materials is given. INTRODUCTIONDue to their outstanding physicochemical properties, such as catalytic activity, conductivity and corrosion/oxidation resistance, precious metals now find extensive usage outside of the traditional jewellery and investment industries. The increasing use of precious metals in such areas as electronics and catalysis, as well as their increasing high value, has led to a growing interest in their recovery and separation from primary and secondary materials.Quantitatively the demand of platinum metals in the western world by area of application is described in Table I. Platinum and palladium represent 90% of the total demand, Rh and Ru 8% and the remaining is taken by Ir and Os. In terms of value the following were the average prices (US$/oz) of the metals in the second half of 1986: 500 Pt, 125 Pd, 1200 Rh, 650 Os, 400 Ir and 80 Ru. Due to these prices, exploration, mining, reclamation and refining activity were very high in South Africa, the biggest producer of Pt metals in the world, as well as in other areas: United States (Stilwater deposit), Canada (Sudbury, Marathon and Lac des Isles, Ontario; Kenly Lake, Quebec, etc.), Australia, Europe and elsewhere"

Jan 1, 1989

By Warnett Kennedy

"GENUINE CONCERN for the environment is a built-in attitude of mind. If you do not have it by age 40 you probably never will. Some people speak the jargon of 'environment' and 'ecology' for political reasons, others because it feeds their need and bias toward attitudes of moral indignation or dissent. Others pay lip-service for purely business reasons. Complete reactionaries equate conservationists, ecologists and environmentalists as either 'commies' or 'pinkos'. Their real credo is the old saying, ""Where there's muck there's brass."" Those who have genuine concern for good environment are not only romantics like Thoreau but realists who sense the danger to our planet if human greed is rampant and unchallenged. The cities are in real trouble. Almost 75 per cent of the population already live in and around cities. Even mining men live in cities or bring up their children in the new 'instant' towns. The ecology of cities is the concern of all. Our distinguished guest Stewart Udall, in his book ""The-Quiet Crisis,"" quoted Thoreau in 1859 as having written ""each town should have a miniature wilderness park, a primitive forest of five hundred or a thousand acres where a stick should never be cut for fuel, a common possession forever."" Mr. Udall will be glad to know that this advice was taken in at least one instance known to me. I refer to Stanley Park in Vancouver. It is a primitive forest of 1000 acres right inside our small downtown peninsula. It remains unmanicured. This month we celebrated the completion of a seawall of 4%, miles along its perimeter. The construction of this wonderful walkway started in 1910. We are very, very proud of our park."

Jan 1, 1972

By Hans Lundberg

An electric survey from a 'plane flown over the ground is much faster and cheaper than an electric survey carried out on the ground. The results are obtained as continuous recordings that are resolvable into both a depth expression and a conductivity effect, so that the indications are easier to evaluate, as well as to correlate from one flown line to the other. The prospecting technique adopted in our electric airborne surveys may be brie fly described as follows: A loop of many turns of insulated copper cable is fastened around the fuselage of the 'plane and connected to a generator supplying a few ampere alternating current, usually of a frequency less than 1,000 cycles per second. Just as the current in the primary coil of a common transformer will induce current in the secondary coil when shorted, the alternating magnetic field from this primary current now induces alternating current in electric conductors that happen to be located in the vicinity of the path over which the 'plane is flown. This induced secondary current in each conductive section of the ground causes, in turn, an alternating magnetic field, secondary field, which disturbs or dampens the normal alternating magnetic field from the primary loop flown by the 'plane. These secondary fields are then picked up and recorded by the help of detecting solenoids, amplifiers, and recorders carried in the 'plane. By closer study of such a secondary field it is possible to localize the secondary current causing it and, thereby, the conducting body that contains the secondary current. In the 'plane are continuously recorded, besides the amplitude or intensity of the field, also the phase, which is a measure of how much the recorded secondary field is out of step with the primary field.

Jan 1, 1950

By R. A. McIvor, R. S. Rafuse

"INCO Limited purchased a custom designed mobile hoist rope winder/tensioner in 1988 from TimberLand Equipment Limited to handle Large hoist ropes and serve as an emergency hoist. This paper describes the operation of the winder/tensioner and some of the different applications that the machine has been used to handle large loads.IntroductionINCO Limited operates 24 mine hoists in the Ontario Division and has approximately 50 miles of mine hoist rope hanging in the shaft plus an equal amount on spare reels. The mine hoist ropes range in size from )( inch to 2.305 inches in diameter with the majority being 1 3/4 inches and above. Prior to the procurement of a new high powered winder/tensioner in 1988, the mine hoist ropes were handled with a variety of methods and equipment using hydraulic or pneumatic powered reel winders. The largest such reel winder has a pull rating of 8000 Ibs and travels approximately 40 ft/min. Head ropes for the tower mounted friction hoists were installed and removed using a magazine on the hoist drum to wind and unwind the rope because the loads were greater than the capacity of the existing machinery. It was recognized that a large high capacity machine would improve the productivity for handling the larger hoist ropes and a feasibility study was undertaken to determine the parameters for such a machine."

Jan 1, 1995

By D. Mraz

"Under high pressure in a deep potash mine, the salt rock behaves in accordance with the concept of a generalized, perfectly plastic substance. The paper presents the evidence of this behaviour and engineering concepts f or room-and-pillar design. IntroductionThe mining and refining facilities at International Minerals &. Chemical Corporation (Canada) Limited are located near Esterhaz y at the southeastern edge of the Saskatchewan evaporites. Ore extraction began in 1962 and at the present time the annual mining capacity is in excess of eleven million tons of potash ore.A generalized geological section is shown in Figure I. The mining horizon is overlay in by 100 feet of rock salt followed by a thin bed of competent dry shale. The strata in the next 1,500 feet are generally competent and locally water bearing. The Blairmore formation contains strata of water-bearing unconsolidated sand. Below the mining horizon, rock salt is interbedded with anhydrite bands.The 8-foot mining bed is distinguished mainly by grade and clay content, as there is no definite bed boundary. The chief mineral s are halite, sylvite and, in some cases, carnallite, with up to 2 per cent disseminated clay. The ore is coarse grained, with crystals averaging one-half to three-quarters inch across.The major mining problem is related to the fact that the Dawson Bay formation, overlying the evaporites, contains areas and channels that are highly porous and permeable and are filled with unsaturated brine under high pressure. Consequently, all mining areas, with no exception, must be so designed that the overburden salt stratum remain s competently supported for the duration of the mine .This paper outlines a successful engineering method of determining the stability of the pillar s and designing a stable room -and-pillar mining system."

Jan 1, 1980

By William Petruk

Mineralogical investigations in connection with gold metallurgy are usually performed to find the reason for poor recoveries by cyanidation or by other leaching techniques. Poor recoveries most commonly are obtained when (I) native gold is encapsulated in an insoluble mineral as "invisible gold"; (2) native gold is coated with a precipitate; (3) gold-bearing products are insoluble in cyanide solutions; (4) carbonaceous material in the ore adsorbs gold; and (5) associated minerals decompose and consume cyanide. Samples of refractory material quite often have low gold tenors. It is difficult to find the gold-bearing minerals in such samples with an optical microscope because the probability of finding trace minerals in samples is small. The probability decreases with decreasing grain size of the gold-bearing mineral and with decreas¬ing gold tenor of the sample. Techniques have been developed to increase the success rate of finding gold grains; some are (1) concentrating heavy minerals; (2) preparing special polished sections; (3) searching with an image analyzer; and (4) dissolving associate silicate and sulphide minerals.

Jan 1, 1989

By Fred Horne

1N THIS PAPER, the writer proposes to limit his comments to few generalized phases of the subject, based on his personal experience in the midwestern United 'States and in one section .of the Coal Branch in Western Alberta. The following statistics are submitted to show the importance that strip mining has assumed in the coal mining industry of the United States. In 1914, 1,281,000 tons of strip coal were produced, amounting to 0.3 per cent of the total production. In 1948, the total was 13~,505,000 tons, representing 23.3 per cent. In 1949, the percentage figure dropped slightly and this can be partially accounted for by the labour disturbances prevalent throughout the year. In 1914, there were 48 power shovels and draglines being used in the stripping of coal; in 1949 there were 3,712, not to mention other types of coal stripping equipment such as bulldozers, tractors and scrapers, rotary excavators, and stackers. At the bituminous coal mines in Western Canada, strip mining was introduced only a few years ago, two of the major reasons for its development being the need for increased production during the war and post-war years and the need to hold the line on increasing production costs, but even in these few years the percentage of strip production has in-creased to such an extent that some mines that, five or six years ago, were producing all their tonnage from underground operations are today obtaining up to 80 per cent of their total output from strip mines.

Jan 1, 1951

Over five decades ago Kitchener et al. in England and La Mer and Healy in the US were advancing our understanding and application of flocculants, primarily related to water treatment and filtration of sludge. This paper identifies the beneficial uses of flocculants in the mining industry and revisits some less common applications. Flocculants are used in unique ways in the mining industry: (a) to increase the effectiveness of sediment ponds to achieve discharge compliance; (b) to eliminate air emissions and costs associated with concentrate drying; (c) to reduce soil loss by applying a flocculant to erodible soils, and reducing wind and water erosion; (d) to remove/thicken metal precipitates in acid rock drainage treatment; and (e) to enhance clarification and thickening in mineral processing. The mechanism of how flocculants, coagulations and potentially-determining ions function is described and how their use can be controlled and optimized. The potential toxic effects of flocculants and coagulants when used to achieve effluent permit discharge compliance for suspended solids is discussed. A review of numerous best management practice (BMP) guidelines for the design and operation of sediment ponds treating mine site runoff to remove total suspended solids (TSS) and turbidity revealed an absence of a predictive methodology to address regulatory discharge compliance for TSS concentration, turbidity and flocculant-induced toxicity. An essential component of pond design is the need to determine whether flocculants and/or other settling aids are required based on the site-specific soil particle size distributions upslope of the pond. Procedures are provided to predict the need for settling aids and estimate pond discharge quality and downstream impact for TSS, turbidity, toxicity and sub-lethal toxicity. The need to develop BMP guidelines are discussed for (a) the application of flocculant to surface soils to reduce erosion, (b) the application of flocblocks to increase the ?sediment control? aspects of erosion and sediment control, as part of the mine site erosion control plan strategy and (c) the application of flocculant to silt socks to treat mine site runoff.

Aug 1, 2013

By Andrew L. Mular, Robert P. Edwards

"The operation of flotation circuits is often regarded as a combination of art and science. Expert systems offer a method by which the art may be captured and supervisory control of flotation circuits fully realized. Operating knowledge, the art, can be consistently employed to enhance regulatory control through the judicious application of an expert system. Using an expert system, a supervisory control routine was developed, and success- fully implemented, in the copper flotation circuit at Brenda Mines Ltd.The expert system ran in conjunction with regulatory PI controllers on a personal computer. The expert system received assays via an on-stream analyzer and adjusted regulatory loop set points as required in real-time. From its commissioning in November, 1989, to the end of the mine 's operation in June, 1990, it was enthusiastically embraced by the operators and attained operating levels superior to those achievable manually.IntroductionExpert system (ES) software springs from research into artificial intelligence and is currently making significant inroads into business and industry. ES proponents make many attractive claims; they are a means of capturing the knowledge of experts and they can be programmed by non-programmers. To date, most uses of this software in the process industry are in off-line applications, meaning that the applications are not tied directly to operating (on-line) environments. Moreover, in on-line environments, they are typically employed as advisors and only suggest changes. Human operators are required to close-the-loop to the process. Yet, an ES should be applicable to operating environments and, if the claims of the proponents are valid, should also be better than existing tools. As an intelligent controller an ES must use the knowledge of experienced operators, apply it directly to a process and do this without the intervention of human operators. On-line applications have been successfully employed in the closed loop control of SAG circuits (Herbst et al., 1989) and flotation circuits (Hales, 1989). Harris and Kosick (1988)detail an implementation for flotation control at the Polaris Mine."

Jan 1, 1992