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By Nabeel Khan

Annual oil production from the Canadian Oil Sands in Northern Alberta has been rising for several decades, and more ore and overburden are excavated each year from an increasing number of open pit mines. Overburden meeting certain specifications will be used to dam tailings and fill open pits, but the remaining material must be stored in overburden storage structures (OBSS). Well-designed overburden storage structures are more stable and cost less in the short- and long-term. The purpose of this paper is to explore OBSS designs that will be stable yet economical in the short- and long-term. The geological background of the site is briefly discussed, including the effect of each of the main geologic layers (recently deposited till and muskeg, Clearwater Formation clay shales, McMurray Formation oil sands, and the Devonian limestone) on the slope stability of the OBSS. Cost is considered in the analysis when balancing between minimizing costs (steeper slopes) and acceptable factors of safety (flatter slopes), all the while considering the financial consequences of failure. Potential failure planes are identified and probabilistic analysis is conducted on the critical failure surface. The variations in the factor of safety caused by varying pore water pressure, friction angle, and cohesion, are plotted and discussed.

Jun 1, 2012

By D. O. DeGagné, J. F. Archibald

Spray-on polymer linings, as partial or full replacement for traditional forms of area rock support, have seen rapid growth in interest within Canada. A wide variety of lining types, ranging from polymer chemical to water-based cementitious materials, have been developed and commercially introduced to the underground mining market. Following approximately one decade of development work, several general conclusions have been reached regarding the performance of this class of area support media, these being that: health and safety assessment of the broad range of materials has shown the majority of them to be acceptable and safe for underground use; significant ground support potential can be offered by them, being equivalent to or better than capabilities offered by traditional support forms such as bolt-and-screen or shotcrete, and; their abilities to be rapidly deployed and provide near instantaneous support restraint offer considerable operational and cost benefits to underground operators. A review of currently available liner materials, their historic development within the Canadian mining industry, and overviews of support, health and safety, operational considerations and cost benefits are provided in this paper.

Jan 1, 2001

By P. Garritsen, J .. A. Blanco, M. C. Bell

"By 1994, Inco Limited will lower sulphur dioxide emissions from the Copper Cliffsmelter by 60% to 265 000 tonnes/year, primarily through implementing two key process changes. First, new milling technology will permit economic rejection of additonal pyrrhotite prior to smelting. Second, a bulk coppernickel concentrate will be oxygen flash-smelted, thereby eliminating the existing multi-hearth roasters and reverberatory furnaces . All copper will be recovered in the matte separation plant as a nickeliferous chalcocite, and will be oxygen flash-smelted for blister production. This paper outlines the development of the project and describes the process, including the flash furnaces, new sulphuric acid plant and additional oxygen plant.IntroductionInco 's SO2 Abatement Program will lower sulphur dioxide emissions at Sudbury from the current levels of 685 000 tonnes per year to 265 000 tonnes per year by 1994 as required by Ontario' s countdown on acid rain regulations.It is the high tonnage of sulphur mined that creates the magnitude of the SO2 emission problem at Sudbury. At a production rate of 240 million pounds of nickel per year, Inco mines 12 million tonnes of ore. At 10% sulphur it mines 1.2 million tonnes per year of sulphur. If Inco did not fix any of this sulphur it would be emitting 2.4 million tonnes per year of sulphur dioxide-about as much as all other Canadian emissions. Today, however, Inco is already fixing 70% of the SO2 in ore, in several ways : mostly as sulphur in pyrrhotite rejected to tailings in the milling operations; as acid from the roasting of pyrrhotite and some nickel concentrate at the Iron Ore Recovery Plant (lORP) and some as liquid S02 from the copper flash smelting furnace. By fixing 70% of the sulphur the current allowable SO2 emission levels of 685 000 tonnes per year is met. Total sulphuric acid production is currently 450 000 tonnes per year and in fact, the 10RP operation is being continued only to maintain established acid markets.Historically emissions have been reduced from the 2 000 000 tonne per year level to the current level of 685 000 tonnes per year by rejecting pyrrhotite from the smelter feed, and 70% of the SO2 containment problem at Sudbury has already been addressed.While Inco's profits are large at current nickel prices, most people have forgotten that back in 1982 Inco was losing a million dollars a day. Inco did make a dramatic response to this economic stimulus. The Ontario Division increased productivity by 65% and lowered costs to become the lowest cost nickel producer."

Jan 1, 1990

By C. S. Liao, S. L. Wang, C. H. Yan, F. X. Cheng

A significant development in the theory of countercurrent extraction will be presented in this article. A new term in countercurrent extraction process analysis, "Adjacent Stage Impurity Ratio" (ASIR), is proposed, and its expression is deduced. Furthermore, based on the term together with mass balance and extraction equilibrium, the conditions where a given countercurrent extraction separation operation can have minimum amounts of both extracting solvent and scrubbing agent solution can be estimated, and the equations of the two minimum amounts can be deduced. It was found that the equations for a two-component separation using a single aqueous or organic feed are exactly the same as they appeared in the theory initially established in the 1970s. Unlike its earlier version, the present derivation does not involve feed-stage-composition hypothesis, and also has the advantage of dealing with a double-feed system where both aqueous and organic feeds are simultaneously employed whereas the earlier theory can only analyze a separation using a single aqueous or organic feed.

Jan 1, 2014

AGENDA ? Company Overview ? Industry Direction ? Technology to support maintenance ? data access, connectivity, process historian, downtime & production reporting. ? Case Studies Company Overview Corporate Offices Client Base ?16 consecutive years of growth & profitability ?#39 of Top 50 Control Companies (Worldwide) ?470 employees ?TSX: MTK Industry Direction Improved visibility into the business so they can: ? Reduce cost through better understanding of where costs are being incurred and making timely decisions. ? Optimize operations while leveraging existing assets. ? Have a single version of the ?truth? ? Deliver reliably to stakeholders on the demand for increased accountability (safety, environmental, regulatory performance etc?). ? Respond quicker to market conditions in order to out perform the competition ? Best in Class approach. Web is becoming the standard user interface.

Apr 1, 2005

By D. R. Wright

"The modest thermal efficiency of the steam turbine cycle essentially determines the heat required and, therefore, the coal consumption and ash production of pulverized-coal-fired powerplants. This paper emphasizes how some properties of coal and its ash can crucially affect the operation of a steam generator and its flue gas cleaning equipment. A brief reference to some siting factors and economics reaffirms the all-pervasive influence of the properties of coal and ash and establishes the importance of a firm supply of cooling water. The economics of scale remains a compelling factor in selecting the size of units, despite disappointing performances by some of the larger units. Environmental considerations suggest that smaller units still have a role to play. IntroductionCoal fuelled one industrial and economic revolution, beginning two hundred year s ago . It was the precursor of competing fuels, notably natural gas, oil and uranium, which eclipsed it in terms of convenience and rate of growth.The turmoil that now exists because of rapidly dwindling supplies of no-longer-cheap oil and the concerns about nuclear energy-justified or unjustified-exacerbated by an operating incident at the Three Mile Island Nuclear Powerplant, prompt speculation for a resurgence of coal, especially where it cangenerate electricity to replace energy from imported oil.The world's reserves of coal are not inexhaustible, although they are ample for several decades. Of greater import is the fact that the world's coal reserve s are more widely distributed than its oil reserves, and they appear less convenient as instruments of economic and political persuasion by opportunist powers. The crux is whether or not the world will accept all that a massive, if temporary, return to coal implies.Combustion of pulverized coal in steam generators to pro duce electricity is a 50-year-old, well-understood technique; it is undergoing continuous refinement to meet evolving environmental and economic criteria and is not found wanting. It is certainly the only technique available and technologically advanced enough to replace oil immediately on a large scale. Although it may take a decade to bring a new coal-fired powerplant into service, this delay is a reflection on nontechnical and administrative processes. Capital and operating costs of coal-fired powerplants are significant and subject to inflation, but, because of the accumulated experience in this field, the ability to control costs is better than for those energy processes which are less mature or still in embryo form. More exotic, soft energy systems, touted as the panacea for world energy problems, have still to prove themselves on the scale they are needed and under the stringent climatic and operating conditions coal-fired powerplants have already mastered."

Jan 1, 1980

By M. A. Keogh

This paper reviews the physical properties that make low-density polyethylene the most practical and economical material for launder• fabrication in the majority of mine and mill applications. The basic design features and use of other launcher• materials are also discussed.

Jan 1, 1976

"During the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests.In the current case, a composite sample of gold ore is dedicated to a Gravity Recoverable Gold (GRG) test. The properties of interest are the head grade of gold, the size distribution of the material, and the gold assay per size class. The sample is mixed and a sub-sample is taken to measure the feed properties: the size distribution and the gold assay per size class. The remaining material of the sample is subject to the first stage of concentration using the laboratory Knelson concentrator. The concentrate is analysed in its entirety, while a sample of tailings is taken for the same analysis. The remaining part of tailings is subject to grinding to feed the second and third stages of concentration. Similar sampling is performed at each stage.The concentration performances are analysed in light of these measurements. But what is the accuracy of the measurements of the properties? Pierre Gy’s theory of sampling, associated with a heterogeneity model built using the GRG test results, will answer this question. The current paper presents, through a real example, the calculation of the errors of the measurements of size distributions and gold assays performed during the GRG test. The uncertainties of the concentration performances and liberation size estimate are then calculated and their impact on the results interpretation is analysed.INTRODUCTIONDuring the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests. In order to take into account the ore variability in terms of gold deportment, it is recommended to perform variability studies (Dominy, Murphy, & Gray, 2011, Dominy, 2013) using samples representing various horizons or years of production. But for a given ore type, it can be necessary to perform many tests with different operating conditions (Brochot, 2012a). In that case, the variability of the samples is not due to the heterogeneity of distribution of the deposit, but only on the heterogeneity of constitution of the primary sample. The level of confidence associated with the estimated performance parameters is directly linked to the overall error (including sampling error) of the measurements performed during the tests."

Jan 1, 2016

By K. Koyama

As a study to establish a new energy-saving copper recycling process, the copper deposition at a cathode and oxidation of copper(I) at an anode from ammoniacal alkaline solutions containing Cu(I) or Cu(II) were investigated in order to examine the feasibility of electrolysis in this solution.. The current efficiencies were greater than 95% in the current density range of 200 to 1000 A m-2. The current efficiency decreased with the increasing Cu(II) concentration and temperature. In the batch-type electrolysis at the anode, during the initial stage, the current efficiencies were 100%, and the anode potentials ranged from 0 to 0.15V vs. SHE at a current density of 100 A m-2. During the subsequent stage, the current efficiency decreased with time, and the anode potential was around 1.35V vs. SHE where oxygen evolution at the anode surface was observed. As a result, the present electrolytic method can be the core technology in the said copper recycling process.

Jan 1, 2007

Slurry flow, including flow through the charge, through the discharge grates, along the pulp lifters and its discharge from the mill is an important contributor to the efficiency of the grinding process within a SAG mill. Poor transport of finer ground material can adversely affect grinding leading to excess energy consumption and over-grinding of fine material. This paper extends a 1-way coupled DEM-SPH method to three dimensions and applies it to a 1.8 m diameter by 0.6 m long AG/SAG pilot mill. This provides detailed information on the internal flow of slurry within a SAG mill, including the prediction of dry regions and of slurry pooling. Full 3D analysis also allows the pulp flow patterns into and out of the mill via pulp lifter chamber to be investigated.

Jan 1, 2012

By R. Butar-Butar, J. Mosher, G. Banini, J. Hollow, A. Villanueva

The effect of High Pressure Grinding Rolls (HPGR), as a preceding stage to a conventional ball mill circuit at PT Freeport Indonesia’s C1/C2 concentrators, has been studied in terms of downstream grinding efficiency and circuit performance. When milling the product from the HPGR, mill capacity increased by 21% for the same product grind size, when compared to processing similar ore from a conventional crushing circuit. This achievement is a result of several reasons, among them: reduction in feed size (F80), fines generation beyond the proportional reduction in F80, reduction in ore hardness induced by HPGR comminution mechanism, optimization of the recycle system of the HPGR and ball string optimization in the ball mill circuit given the new feed to the mill.

Jan 1, 2012

By J. M. Paxton, R. L. Roscoe, G. A. McCreary, W. W. Muir, T. J. Drown, D. A. Barr, T. W. Law

"This paper reviews the complete cycle of a small mining operation in a remote section of northern British Columbia, including discovery, exploration, development and production. The discovery of high-grade epithermal gold-silver mineralization occurred in 1969 following a regional geochemical reconnaissance program designed to search for porphyry copper mineralization in the Cassiar-Omineca Mountains. Exploration and development from 1971 to 1979 included geological, geochemical and geophysical surveys; trenching, almost 30 000 feet of surface and underground drilling in about 100 holes and cross-cutting, drifting and raising on the principal goldsilver- bearing vein. This led to the delineation of 100000 tons at an estimated grade of0.9 oz gold per ton and 18 oz silver per [on to an average depth of 120 feet below surface. of a 100-ton per day mining operation employing about 50 personnel with all supporting infrastructure transported to the site by a Hercules aircraft. The operation was subsequently supported by its own Twin Otter aircraft with periodic Hercules campaigns supplying major items including fuel.The mining operation included both open-pit and cut-and-fill methods. The milling operation employed conventional cyanide leach process with cyanide destruction initially by alkali chlorination and subsequently by the Inco SOl /Air process.The fly-in operation, initially structured on a 21-day-in and 7-day-out basis was modified to al-t-day-in and Z-day-out basis with no loss in efficiency and with a significant increase in employee satisfaction. The operation, which earned the B.C. Small Mines Safety A ward in two consecutive years in its Ll-month operating history, emphasized safety and process hazard awareness. Wildlife studies in the environmentally sensitive mine area also showed that industry and wildlife can coexist in harmony.Most importantly, the paper compares the feasibility assumptions with actual operating experience."

Jan 1, 1986

By Avi Nanda, Robert Brandt, Alex Piatkiewicz, David M. Jones

In 2010 the United States Environmental Protection Agency (UESPA) revised the National Ambient Air Quality Standards (NAAQS) by lowering the permissible value to a 1-hour average SO2 concentration of 75 ppb. In 2012, the USEPA designated the Miami area as non-attaining for the new SO2 NAAQS. A number of options were studied to assist in bringing the Miami smelter into attainment with the new standard. The chosen solution included: Installation of a large tertiary hooding system over the converter aisle; Hooding of the anode vessels and treatment of the anode gas in a baghouse; Installation of a large 2,325,212 Nm3/hr caustic scrubber to treat the captured converter fugitives and anode off-gases; Installation of a secondary ESP for the tapping fugitive off-gas treatment system; and the continuous scrubbing of all acid plant tail stack gases. The modifications have reduced smelter SO2 emissions by 85%, achieving a world class SO2 stack emissions rate of 0.45 kg of SO2/tonne Cu. INTRODUCTION The Freeport McMoRan Miami smelter has been previously described in literature (Steinborn, Pasca, Sallee, Binegar, Bhappu). For the sake of brevity a brief description is given here. The Miami smelter is located 129 km east of Phoenix, Arizona near the town of Miami, Arizona. The smelter was established in 1915 and has undergone a number of process upgrades and modernizations over the years. The present smelter consists of an Isasmelt furnace, an electric settling furnace, four Hoboken converters, two anode refining vessels & one casting wheel; and one double contact sulfuric acid plant. Concentrates are railed & trucked to Miami from four Freeport McMoRan mines located in Arizona & New Mexico. The wet concentrates, typically containing 10% H2O with a Cu/S ratio of 0.85, are smelted in an Isasmelt furnace to a matte grade of 58%. The entire output from the Isasmelt is laundered into an Elkem electric furnace (originally installed in 1972 as the primary smelting furnace) for separation into matte and slag. Slag containing 0.85% Cu is skimmed from the electric furnace and discarded. Molten matte, containing 60% Cu, is tapped from the electric furnace and processed in one of four Hoboken converters to produce blister copper. Two anode refining vessels further refine the blister copper before the final product is cast on a single, 30 mold, casting wheel. All of the anodes produced at Miami are shipped to the Freeport McMoRan electrolytic refinery in El Paso Texas for refining into cathode copper. Smelter off-gases from the Isasmelt, electric furnace and Hoboken converters are combined and treated in a double contact acid plant to produce sulfuric acid. Acid produced at Miami is internally consumed at Freeport McMoRan mines in the region.

Jan 1, 2019

The paper will cover the basic reasons for alkaline leaching, a brief description of the circuit and the reasons for the flowsheet used. Changes made to the flowsheet, including the use of mechanical agitation of pachuca slurry, the use of oxygen and its effect on extraction, the use of lime and its effect on process economy, and the environment, will be described. A brief description of a unique semi-autogenous mill and future circuit changes will be included.

Jan 1, 1979

By Man-Chao He

One of the critical problems involved in deep coalmines is unusual gas emissions. Many researchers agree that there is a relationship between coal gas emissions and geological features such as tectonics or geological disturbances, gas content, properties of the coal and rock and the mininginduced stress state in the coal seam and rock. Thus, the present paper intends to investigate complex mechanical phenomena during the process of gas emission in underground coal-mines. A program of laboratory testing was undertaken to study the effects of temperature and pressure on mechanisms of gas emission. It must be noted that this paper describes new techniques developed to simultaneously measure deformation and gas pressure, as well as flux during the test, taking the characteristics of gas transport into consideration under certain temperature and pressure conditions. The results indicate that under certain temperature and pressure conditions, gases adsorbed to coal start to desorb, and increase the pore pressure. High pressure gases entering coal fractures can generate high tensile stresses near the crack tips, leading to crack propagation and coalescence, which in turn can cause the specimen to dilate. From the experimental viewpoint, these test results may help us discern why mining seismic events can trigger gas emissions.

Aug 1, 2013

By P. R. A. Andrews, I. Jackman

"A mineral processing investigation to recover chromite was performed at Lakefield Research, under the guidance of CANMET personnel, on a 70 tonne ore sample from the Bird River deposit in Manitoba. In the laboratory phase a flowsheet was developed which involved grinding, gravity separation and flotation. The gravity concentrates were upgraded by magnetic separation and the flotation concentrates by gravity concentration. Pre-concentration by electronic ore sorting, magnetic separation and heavy media separation also was examined.The developed flowsheet was applied on a pilot-plant scale in the second phase of the testwork to the ore as received, and to ore pre-concentrated by electronic ore sorting and magnetic separation. Ore pre-concentrated by heavy-media separation was treated on a laboratory scale based on the pilot-plant flowsheet.Processing the are as received resulted in 77% recovery of chromite in a concentrate analyzing 30% Cr20 J; processing are pre-concentrated by electronic are sorting resulted in 64% recovery of chromite in a concentrate analyzing 30.5% Cr20J.IntroductionA five-year mineral development sub-agreement was signed between the federal government and the province of Manitoba in 1984. The purpose of the agreement was to establish a work program which would strengthen and diversify the mineral resource industry of Manitoba. Basically, the agreement covers three sectors: Sector A, geoscience; Sector B, mining and minerals technology research; and Sector C, development studies.Project selection involved input from industry, federal and provincial representatives. In the case of industrial mineral s, the selection was initiated at a meeting held at the offices of the Department of Mines and Energy, Winnipeg, Manitoba, in October 1985. One such project was the evaluation of the chromite ore deposits at Bird River, Manitoba."

Jan 1, 1988

By P. R. Stephenson

Mining projects depend on the amount and quality of the mineral reserves, which in turn depend on the amount and quality of the mineral resources. Only Measured and Indicated Resources may be converted to mineral reserves and Inferred Resources may not, with certain exceptions, be used in economic studies. Responsibility for the estimation of mineral resources rests with the Qualified Person (QP) and there is a wealth of literature, text books and case studies to guide the QP. Responsibility for the classification of the mineral resources also rests with the QP. While there is some industry guidance and common practice on approaches to resource classification on which the QP can draw, the process is (or should be) heavily dependent on the exercise of judgement by the QP. However, this inevitably leads to situations where, for example, one QP?s Inferred Resource is another QP?s Indicated Resource. If the QP?s judgement is poorly reasoned or illogical (as is sometimes the case), it can have a major impact on the project, often with substantial cost or value implications. Project managers and company executives should not unquestioningly accept QP?s classification decisions and should apply the same intensity of due diligence that they apply to other critical elements of the project.

May 1, 2011

By I. Spector, A. J. Smith

In 1967, BACM Industries Limited started producing walboard at Saskatchewan's first gypsum products plant, located in Saskatoon, using, as a basic raw material, gyp-sum rock supplied from the company's mine near Amaranth, Manitoba. This paper describes the geology of the Amaranth gypsum deposit, the method of mining the rock and the manufacturing facilities used to produce wall-board.

Jan 1, 1970

By E. I. Vargha-Butler

The determination of surface tensions and contact angles of coal particles is of great interest for coal beneficiation processes such as froth flotation and oil agglomeration and for the inclusion of coal particles into oil droplets as a means of enriching the fuel. Methods for contact-angle measurements on small irregularly shaped solid particles have not been available in the past. Therefore, we recently developed a novel technique to determine contact angles and surf ace tensions of coal particles. Two types of bituminous and one type of subbituminous coal particles have been tested. The technique used is called the freezing-front technique and it considers the behaviour of the test particles (in the range of 20-250 pm) at the solidification front of carefully selected, well-defined solidifying melts (matrix materials) such as thymol, biphenyl, naphthalene, salol and 2-phenyl phenol.The results show that the technique works well, providing quantitative and detailed information on the wettability of coal particles. The sensitivity of the method is so high that a difference in contact angle of approximately 4 degrees between the smaller and the larger particles is clearly registered.

Dec 1, 1981

By C. Bissue, G. M. Castillo

Newmont’s Phoenix mine started production in March of 2006. Due to the extreme hardness of the ore, the mill has struggled to meet throughput projections. Grinding studies showed that optimizing the existing circuit would not achieve budgeted throughput. These studies also showed that the pebble crusher was being underutilized due to the inability of the SAG mill to break the rock. The concept was developed to supplement the feed to the existing pebble crusher with a secondary crusher. Models of this process looked favorable so a portable crusher was installed to test the process. The temporary crusher was successful at increasing the throughput by 7% and based on the operating data, plans are currently being developed to install a permanent secondary crushing system in front of the SAG mill. This paper will review the results from the test crusher and the flow sheet for the permanent secondary crusher.

Jan 1, 2012