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By Liguang Wang

The froth phase in flotation has received much less attention than the pulp phase despite the fact that froth stability plays an important role in determining flotation performance. Froth stability is largely determined by the stability of thin foam films, which in turn has a strong correlation with the critical rupture thickness (Hcr) of the films. In the present work, a new approach to predicting the Hcr values of thin foam films in flotation froth phase was proposed and examined. The Hcr values were calculated using an advanced capillary wave model with input parameters being surface tension, film radius, capillary suction pressure, and intersurface force. The intersurface force was estimated by using the Stefan-Reynolds lubrication approximation to fit the measured thinning rates of single foam films formed in a Scheludko ring cell, where the film radii were less than 50 microns and were kept constant during the film-thinning process. A comparison between the predicted and experimental Hcr values was made for the films with the use of sodium chloride as background electrolyte and in the presence of various frothing reagents such as methyl isobutyl carbinol (MIBC), polypropylene glycol with an average molecular weight of 400 (PPG400), and sodium dodecyl sulphate (SDS), at different concentrations and film radii. It was found that the model correctly predicted the trends of Hcr-versus-concentration and Hcr-versus-film radius curves. Moreover, the predicted Hcr values matched well with the experimental ones of the foam films containing either SDS or PPG400. For the foam films containing MIBC, however, the model overpredicted the Hcr values. The reason for this discrepancy was discussed.

Jan 1, 2016

By John Starkey

This paper examines 5 years of SAGDesign testing data with particular emphasis on the grinding test results from two recent projects, the Fortune Minerals Limited NICO project, and the Aurora Energy Resources Inc., Michelin deposits, located in the Northwest Territories and in Labrador respectively. The context is to compare these results with the SAGDesign database. The required SAG mill pinion energy for these two ores showed vast differences, even though both ores had similar average Bond Ball Mill Work Index values - about 13 kWh/t each for the two deposits respectively. Bond Rod Mill Work Index values for NICO ranged up to 19.7 kWh/t for the hardest ore, confirming the harder nature of the coarse material. SAG mill pinion energy to grind the NICO cobalt-gold-bismuth-copper ore from F80 152 mm to T80 1.7mm varied from 16 to 35 kWh/t, while for Michelin uranium ore, it varied from 2 to 9 kWh/t. NICO ore is harder than any other material encountered to date using SAGDesign testing. SAG pinion energy is more than double the ball mill pinion energy using a transfer size T80 of 1.7mm and a final grind P80 of 74 microns. For NICO, the ore is ?off the charts? for simulation design techniques because there is no comparable operating SAG mill treating ore that is this macro-competent. For Aurora, the relationship between SAG and ball mill pinion energy is reversed in that the SAG mill requires less than half of the ball mill pinion energy using a transfer size T80 of 1.7mm and a final grind P80 of 90?. Because these discoveries are so important for grinding mill design, their impact will be dealt with in future papers, at the August METSOC Conference in Sudbury, and at the September SME Workshop in Tucson. It has now been concluded that the ratio of SAG pinion energy to Bond Ball Mill Work Index, is valuable data to use in designing a SAG/ball mill grinding circuit, to help choose the power split needed.

May 1, 2009

By J. R. Meyer, P. L. Dean

"The Department of Mines and Energy is at present investigating the dimension-stone potential of the Nain anorthosite complex. These rocks are known to host occurrences of labradorite, a semiprecious gemstone known for its beautiful play of colours (chatoyance). Test blocks that contain 5% to 18% chatoyant labradorite were extracted from three prospects south of Nain. These have been slabbed and polished for further evaluation.Second-grade labradorite stockpiled around the Grenfell quarry on Tabor Island is also being evaluated as a potential source of aggregate for use in terrazzo tiles, precast concrete and epoxy-backed wall panels.IntroductionThe Nain anorthosite complex consists of approximately 10000 km2 of anorthosite and related basic rocks , which are well exposed along the coast of Northern Labrador (Fig. 1) (Emslie et al., 1972). These rocks have been known for centuries to host deposits of gem-quality labradorite. The chatoyant nature (i.e. the play of colours or labradorescence) of this semiprecious feldspar has been utilized mostly in the making of jewelry and other polished, handcrafted products. In the early sixties, Brinex Limited (now Brinco Limited) attempted larger scale commercial exploitation of labradorite, including use 'as building stone and in polished precast concrete for facings on buildings' (Brummer, 1984). After six years of work, which included market studies, Brinex decided that, at that time, the demand did not warrant further production.In recent years, there has been a dramatic increase in the markets for dimension-stone. In the period from 1980 to 1985, the demand in the United States for granite, much of which is imported, has increased 1735070 (Marble Institute of America, 1986). The dimension-stone industry's remarkable growth rate has, in part, resulted from new technology that makes it easier and faster to quarry and cut stone. This has allowed natural storie to compete with other building materials. Now, it is not only used for exterior cladding and walkways, but also on interior walls and floors, and in home and office furnishings, such as countertops for kitchens and bathrooms, table and desk tops, stairways, window sills, and fireplaces."

Jan 1, 1988

By Jean-Claude LeRoy, Herman Keller

"INTRODUCTIONEROCON's work is the reclamation of mine wastelands. It has had considerable experience in particular in the reclamation of gold mine tailings in the Canadian Shield since the latter part of the sixties when most gold mines were closing down.A typical example is the famous Hollinger Mine in Timmins which produced $566 million worth of metal from 1910 to 1968 and had left behind some 56 million tons of tailings covering about 1,000 acres which were reclaimed on very short order and are now lush meadows of agricultural quality.To date, practically all gold mine tailings have been reclaimed once and for all by establishing a permanent, self-sustaining and maintenance free vegetation cover.RECLAMATION & THE MINING TOWNSThe first appreciation of people in a mining community where the tailings have been revegetated will be noticing one day the elimination of dusty conditions that used to arise formerly on every dry and windy day. In that respect, EROCON encourages not only vegetating the tailings but also the immediate surroundings of the mills and plants themselves at active mines. The elimination of windborne dust will result in an appreciable decrease in maintenance costs of plant and machinery and more pleasant working conditions for all."

Jan 1, 1975

By R. P. Nicholson

On September 3rd, 1947, the Acadia Coal Company put into operation a central coal preparation plant. This plant was designed to process all coals mined by this Company in the Pictou County coal field. The problem, briefly, was to make a three-way separation of the raw coal fed into the plant. It was desired to remove all stone, metal, and wood from the marketable coal and to produce a splint coal from the raw material which would be suitable for making power. This splint coal product is belted directly to the power plant which is adjacent to the wash plant. To attain this object it was therefore necessary, first, to wash the raw coal, removing all splint, stone, metal, and wood. The stone, metal, wood, and highest-ash splint had then to be removed by a second washing in order to obtain the lower-ash splint for use in the power plant. The plant is on the east side of the Allan colliery, in the town of Stellarton (see accompanying photograph). It is of steel frame construction with wood siding, covered on the exterior with corrugated galvanized iron. Considerable concrete had to be poured for the foundation piers as the plant site is largely 'fill' ground. This necessitated the construction of extremely heavy footings containing a large amount of reinforcing steel. In all, 884 cu. yds. of concrete were poured for the various pits, tanks, and foundations; its average test was about 3,500 lb. per square inch. At the time the plant was constructed, the steel shortage in Canada and the United States was acute and, in order to obtain steel for the structure which is four stories high- an unused part of the Allan bankhead was torn down. Enough steel was obtained from this demolition to fabricate the new plant.

Jan 1, 1948

By Derek H. C. Wilton

"The Cape Ray Fault Zone of southwestern Newfoundland contains two notable electrum/ base metal sulphide quartz vein lode occurrences hosted by two contrasting lithological units, viz. a graphite schist horizon and a granite. The two occurrences, although in proximity, are not in direct contact, but, based on geochronological, geochemical and isotopic evidence, they were apparently deposited from hydrothermal fluids generated as a vapour phase from the magmatic progenitor of the Windowglass Hill granite.This paper provides further evidence, from REE and background A u and Ag data, for the magmatic origin of the hydrothermal fluids. Wall rocks to the electrum-bearing quartz veins in both the schists and granite have experienced a LREE depletion probably due to leaching by Cl-bearing solutions. Gold and silver contents are typically low in all rock types but there is a slight elevation in gold concentrations in those units in contact with the Window glass Hill granite. The granite also has the relatively highest gold and silver contents of any unit in the region.IntroductionThis paper presents the evidence from rare earth element (REE) and gold/silver concentration data for the magmatic origin of hydrothermal fluids responsible for deposition of the Cape Ray electrum deposits of southwestern Newfoundland. The two deposits occur in the Cape Ray Fault Zone (Fig. I) within the Windsor Point Group and Window glass Hill granite. The larger occurrence is called the Main Shear Showing and consists of a deformed quartz vein horizon, which extends for - 6 km, within the late Devonian Windsor Point Group. This unit is an intermixed ignimbrite and mafic tuff sequence with associated schists (metasediments) and gabbros. The host rocks to the mineralized quartz veins are interleaved graphite, chlorite and sericite schists. Basal ignimbrites within the Windsor Point Group have been dated, by Rb/Sr isotopic methods, at 377 ±21 Ma (Wilton, 1983a). The basal ignimbrites also have enriched REE patterns, an elevated initial Sr ratio (0.709) and a peraluminous-siliceous nature which suggest they resulted from the partial melting of continental crust (Wilton, 1984)."

Jan 1, 1985

By Paul MacLean

MAC TSM ?Mining and Biodiversity Conservation 1.Corporate biodiversity conservation policy, accountability and communications 2.Facility-Level biodiversity conservation planning and implementation 3.Biodiversity conservation reporting ?Activities indicative of level AA -AAA (formerly 4-5) performance: ?Independent verification ?Integration into broader business strategy and planning processes ?Engagement with communities of interest ?Commitment to actively partner with other organisations for biodiversity conservation

May 1, 2011

By Gerhard Heinrich

"The composition and the possible utilization of a slag sample from a nickel smelter operation in the Sudbury district were investigated. The sample containing 0.136% Ni, 0.10% Co and 0.29% Cu could be characterized as a fayalit e slag with a sulphide bearing glass matrix. While the fayalite contains most of the Co, Ni is enriched within both sulphides and fayalite. Cu is only present in higher amounts in sulphides or metallic droplets. This, as well as the small grain sizes of the mineral phases, inhibits significant enrichment by mechanical methods. However preconcentration is possible by means of magnetic separation. An effective hydro metallurgical approach proved to be oxygen pressure leaching with sulphuric acid. Accordingly, the method proposed for processing the investigated slags is to combine the normal utilization as coarse construction material with pressure leaching of the fines and the ground upgraded magnetic fraction. Besides the recovery of base metals, the leaching process yields fine-grained residues, which, after addition of CaD, will set to a cement-like material, or can be used as a pozzolanic cement colour. INTRODUCTIONDuring the pyro metallurgical processing of nickel ores, the valuable metals nickel, cobalt and copper are enriched within the sulphide matte, similar to the smelting of copper ores. The resulting waste materials are slags, which may still contain valuable metal contents of up to 0.5% or above . These contents are close to the cut-off grades of some nickel-cop per-cobalt deposits. The methods that are used to recover copper from slags comprise in general further pyro metallurgical treatment, often after enrichment by flotation. Another area of application for such slags is their use as construction material. However, this might cause environmental problems if nickel containing dusts are produced.Based on one example, the characerization and a possible way of complete utilization of nickel smelter slag s as construction materials in combination with partial base metal recovery are described in this paper. The investigated slag sample was obtained from a dump site in the Sudbury district, Ontario. Detailed test series for process optimization were not possible during this study due to the limited available sample size."

Jan 1, 1989

By H. Zhu, Y. Sato, O. Takeda, K. Nakano

Recycling of rare earth magnet wastes is essential to insure the stable supply of rare earth resources. For the development of a novel recycling process, the removal of rare earth oxide from an off-spec alloy magnet was investigated by melting the alloy magnet at 1503 K together with fluoride flux, LiF-50 mol% NdF3 and LiF-?25 mol% NdF3-25 mol% DyF3. After melting, the separation of magnet alloy from the fluoride flux was achieved, and neither suspension of alloy in the flux nor suspension of flux in the alloy was observed. Oxygen concentration in the alloy decreased from 5000 mass-ppm to 160 mass-ppm by utilizing 1.5 times of equivalent amount of flux needed to completely dissolve the oxide. The investigated process is suitable for mildly contaminated waste such as a used (end-of-life) magnet because of its simplicity, low energy consumption and small limitation on location for operation.

Jan 1, 2014

By J. P. McGeer

"With the ever-increasing flood of new science and technology has come a new approach to design. The combination of these factors has produced an ever-accelerating pace of materials substitutions.Examples to illustrate the points made above will be given. An overview of the current new materials fields will follow. Finally, the particular nature of the challenge for Canada will be discussed. IntroductionThere are a number of forces currently at work which make it mandatory that the Canadian resource sector re-examine its strategies and policies. The author thinks there need to be very significant changes in the business plans of Canadian mineral processing corporations. Current changes in our environment demand such a reaction.The changes in our environment include more rap id substitution of materials; a significant alteration in design philosophy; the global economy; and market saturation and market diversification in dev eloped countries.This paper will cover the changes and illustrate how they will affect the Canadian resource industry. It will show some of the ways that Canadian corporations are reacting to maintain profitability. Finally, some policy issues will be considered"

Jan 1, 1988

By Barry W. Schmitke, J. M. Marino

"Cigar Lake Mining Corporation is presently operating an underground test mine in northern Saskatchewan, with a view to developing a high grade uranium deposit. The mining test is intended to demonstrate that the innovative mining methods designed are safe and economical. Two vertical mining methods are considered for the test:• box hole boring from the lower level;• blind boring from the upper level.In both cases, it is anticipated to freeze the ground before excavation to ensure hole stability and limit the inflow of water. Special care will be taken to minimize radiation exposure of personnel.Remote controlled equipment will be used where applicable.The access to the orebody was an important component of the test. After shaft sinking to a depth of 500 m, development work commenced at the 420 level in fractured sandstone which was grouted to restrict the inflow of formation water. The drifting continued in a section of poorly consolidated sand, clay and sandstone; this area was frozen to allow stabilization prior to excavation. At the 480 level relatively little water was encountered in the altered basement gneiss and grouting was not necessary; however, extensive ground support was required in the soft ground areas."

Jan 1, 1992

By G. M. Brownell

A DEPOSIT of hematite occurs on Black island, lake Winnipeg, at a point known locally as Red Rock, on the south shore of the island directly across from Clements point. The mail boat from the Canadian Pacific Railway terminus at Riverton, crossing the lake to Manigotogan twice weekly, passes near Red Rock and provides a convenient means of transportation to this part of Black island (Figure 1). HISTORICAL The occurrence of hematite on Black island has been known for a long time. Dowling's report of 1898 states(1): "An iron-ore deposit on the south side has been known' for many years, and on Jeffrey's map of 1762, showing Canada and northern part of Louisiana, Iron island is shown a short distance south of the narrows, evidently the same as the Black island of today".

Jan 1, 1945

By T. S. Li, D. Ilievski, I. Livk

Micromixing of the fluid and the particulate phases in a continuous gibbsite precipitator was investigated for three different micromixing states, namely maximum mixedness (MM), complete segregation (CS), and maximum mixedness of the fluid but complete segregation of the particulates (MMF-CSP). The influence of the micromixing on continuous precipitation of gibbsite was studied at different precipitation conditions via simulation. Three different cases were considered with respect to the precipitation kinetics: (1) gibbsite secondary nucleation is favoured with slow crystal growth and agglomeration rates; (2) gibbsite crystal agglomeration and growth are dominant mechanisms with secondary nucleation suppressed; and (3) gibbsite crystal growth is the only relevant phenomenon. Simulation results for the cases (1) and (3) showed that the crystalline products for both the MM and MMF-CSP micromixing states were very similar, but the product obtained from the CS micromixing state was considerably different. This indicates that at those precipitation conditions the fluid micomixing has the dominant effect on the product properties, and the particulates micromixing effect is insignificant. However, when operated under the conditions of fast crystal growth and agglomeration kinetics, i.e. case (2), both the fluid and the particulates micromixing were found to affect the precipitation process, resulting in a significantly different product. Computational Analysis in Hydrometallurgy 35th Annual Hydrometallurgy Meeting held in conjunction with the 44th Annual Conference of Metallurgists ofCIM Calgary, Alberta, Canada Edited by

Jan 1, 2005

Fiabilité Totale d?Usine (FTU) Plan de la présentation ?Théorie de l?entretien ?Analyse comparative juin 2005 ?Session de travail 2005-2006 ?Suiviet Résultats(IndicateursdePerformance)

Feb 1, 2008

The Discrete Element Method (DEM) is a powerful tool for analysing the flow of charge, the energy consumption and the pattern of energy utilisation of a SAG mill. With the development of laser scanning measurement, the detailed internal working surfaces of a SAG mill can now be included in DEM models. Using scanned results for new and worn shell liners for a 32? (9.75 m) SAG mill, it is shown that the feed and discharge lifters have significant effect on the flow of the charge introducing significant threedimensionality. The effects of the resolution accuracy of liner geometry and the lower cut-off of the rock size distribution are explored. Finally, using a matched new and end of life worn liner and operating conditions taken from site surveys, the effect of wear on charge motion, distribution and energy utilisation are evaluated.

Jan 1, 2012

By Khosrow Ebrahimi

We document the occurrence, mineralogy and firing properties of magnesite from hydrothermal deposits in the upper Cretaceous ophiolites of Eastern Iran. These deposits occur as thin veins of nearly pure cryptocrystalline magnesite with only trace amounts of quartz, calcite, and dolomite. Ratios of CaO/SiO2 in the bulk ore are variable. The composition of dead-burned magnesite from these deposits, calcined at different temperatures and durations, is predictable from phase equilibria. Textures of the calcined magnesite were studied by SEM; results show that the principal impurites produced during calcination are forsterite, monticellite, merwinite, dicalcium and tricalcium silicates, and that these are located principally at triple junctions of the periclase crystals. The size of periclase crystals increased with temperature and duration of calcination and the amount of periclase-periclase grain contacts was reduced by increasing the concentration of impurities in the starting products. EPMA show: 1) that CaO and FeO contents in periclase increase steadily with an increase in the CaO/SiO2 ratio and the FeO content of the bulk ore, respectively, and 2) that limited solid solution exists between impurites. This study demonstrates that high quality dead-burned magnesia refractories can be produced from the Iranian magnesite with low CaO, SiO2 and FeO contents.

May 1, 2004

By P Kovacs, D. L. Flock

For the purpose of reservoir-performance calculations a balance can be made between the materials with-in the reservoir and the production from the reservoir. The material balance equation, a relationship which holds under or near equilibrium conditions, has been used in many forms by the Petroleum Engineer for the determination of initial oil-in-place in the reservoir and the calculation of performance into the future. One of the more recent methods developed by Tracy, utilizes a modified form of the Schilthuis material balance. In the latter case, values of incremental production are assumed for a particular pressure drop, a value of the gas-oil ratio found and a check of this estimate made by calculation"' the initial oil-in-place. Tracy's method utilizes an estimation of the instantaneous gas-oil ratio and by trial and error a value of the gas-oil ratio is

Jan 1, 1961

By Cy Jordan, Ben Burdett, Adrian Dance, Jack Rainey

"In 1997, EIMCO Minerals installed a knowledge-based control system on one of the five primary grinding lines at Highland Valley Copper. The objective of the system is to maximise throughput without affecting circuit product size or flotation recovery. The system was commissioned in October 1997 on a SAG mill/ball mill circuit following a plant audit and upgrade of the control instrumentation.The system monitors and controls the SAG mill power, bearing pressure and recycle load by manipulating the solids feedrate, water addition and mill speed. The two ball mill and cyclone circuits are controlled through water addition at various points in the circuit as well as the number of operating cyclones.An on-line particle size analyser is used to measure the cyclone overflow quality. Models of the SAG mill charge level and overflow product size are also incorporated. A method of predicting the SAG mill power response to feedrate changes is used to lessen the effect of dead time for improved mill power control. In the future, inferred measurements of SAG feed particle size and hardness will allow changes in ore behaviour to be predicted and compensated for by the system.This paper describes the development of the project -from installation and commissioning to modifications and refinement -along with prospects for the future.BackgroundIn early 1997, EIMCO Minerals was contracted by Highland Valley Copper to install a knowledge-based or expert system control strategy on one of the five grinding lines in the mill. This was to become the start of the Advanced Control Project at Highland Valley Copper (HVC). This paper will review the progress of the Project as well as discuss the prospects for the future.Following a preliminary engineering study (or plant audit) by EIMCO in 1996, it was decided to implement an advanced control system in order to improve plant operations and increase productivity. The study suggested that such a system had a pay-back period of a few months through increased throughput without loss in flotation recovery. Highland Valley already had successfully applied higher level control through their Elsag Bailey distributed control system (DCS) and this was the next stage in process optimisation."

Jan 1, 1998

By D. Asefi

A new method to detect microstructural features such as recovery and recrystallization as well as cold rolling reduction in low carbon steels was developed based on magnetic hysteresis loop measurement. To this aim, a hysteresis loop measuring apparatus, specifically designed and assembled for plate samples was employed. It is shown that maximum field (Hmax) of hysteresis loop, measured at constant maximum flux density (Bmax) of 0.5T, is an adequatemagnetic property to monitor different stages of changing microstructures during annealing.

Oct 1, 2011

By Jean-Francois Magnan

"The old conventional process to produce lithium raw material dates from 1954 (CA patent #504477A). This process produces low purity lithium carbonate (Li2CO3) only. To obtain battery-grade carbonate, another polishing process is needed. To further obtain lithium hydroxide, another chemical conversion process is needed. That is why historically, the value of lithium hydroxide has always been higher than that of the lithium carbonate precursor. With the old conventional process, the low quality lithium carbonate is precipitated from a lithium sulfate solution (Li2SO4) by adding soda ash (sodium carbonate and its impurities). The resulting reaction produces significant quantities of sodium sulfate (salt cake) as a by-product with amounts larger than the impure Li2CO3 recovered with part of the soda impurities. When this conventional process was invented, the salt cake by-product was not an issue: it was discarded in a river near the plant. This practice cannot be done today in North America. While looking to find a solution for salt cake, electrolytic salt splitting of Na2SO4 into NaOH and dilute sulfuric acid appears as a technically feasible solution to get a rid of the salt cake. However, the sodium sulfate salt splitting process has difficulties to economically compete with the chlor-alkali process, which produces millions of tons of NaOH from sodium chloride (NaCl) every year.In contrast, the process developed by Nemaska to directly produce LiOH by Li2SO4 salt splitting not only solves the environmental problems related to the conventional process to produce lithium carbonate raw material, it also produces very high purity lithium hydroxide monohydrate directly at very competitive OPEX cost in comparison with industry peers (Figure 1). It also drastically reduces the amount of reagent and the direct greenhouse gas emissions."

Jan 1, 2016