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By A. Danaei, A. McLean, M. Barati, C. Ravindran

"The aluminum industry generates about 90 million tonnes of red mud each year. Previous research shows it could be utilized as a refining flux with a high capacity to absorb phosphorus and sulphur from hot metal in the steel industry. The present study was undertaken to evaluate the melting properties of such fluxes, as it affects the effectiveness of the flux. The results show that the melting behavior of red mud is strongly affected by lime addition and the characteristic melting/softening temperatures reach minimum VALUES (at 32.7 wt% CaO. From these findings, a correlation was established between melting behavior and optical basicity. This allows one to adjust the composition of the flux based on the process requirements. INTRODUCTIONThe aluminum industry generates about 90 million tonnes of bauxite residues each year. This residue is usually red in color because it contains a substantial amount of iron oxide. The red mud, as it is called, is a solid waste with a high concentration of sodium oxide, high pH (10 to 13), and high alkalinity, and thus is harmful to many forms of life. Traditionally, the material is stored in large tailings ponds within the plant’s vicinity (Power, Grafe, & Klauber, 2009). Development of solutions for safe disposal or preferably using this residue for other industrial processes or applications could help restore polluted locations and eliminate a negative impact on the environment (Haake, 1988; Power et al., 2009; Yan & Xuegong, 2010).The mineralogy and chemical composition of red mud depends on the quality of the bauxite and refining process parameters. In general, it consists of iron oxide (Fe2O3), aluminum oxide (Al2O3), titanium oxide (TiO2), sodium oxide (Na2O), silicon oxide (SiO2), and calcium oxide (CaO) (Power et al., 2009). Like most ores and soils, bauxite can contain trace quantities of metals such as arsenic, beryllium, cadmium, chromium, lead, manganese, mercury, nickel, and naturally-occurring radioactive materials, such as thorium and uranium. Most of these trace elements stay in the residue (Power et al., 2009)."

Jan 1, 2012

By Stephen Hardcastle

Supplying ventilation in underground metal mines can be one of the most energy demanding services required to support production activities. Consequently, as energy, in the form of electricity or combustible fuels can be expensive and their unit cost is expected to increase, there is significant interest in reducing the overall demands of a mine?s ventilation system through such initiatives as controlling ventilation based upon demand and exploring other power alternatives to the current usage of the diesel engine in mobile mine vehicles. However, determining the benefit of any energy saving technology is complex and not universal applicable across the industry, consequently they have not been widely adopted. For these technologies to succeed they must be strategically applied based upon sound business cases. The intent of this paper is to provide information on some of the prospective control strategies and their potential impact on the power consumption related to supplying ventilation.

May 1, 2007

By Xueyuan Nie, Xuezhi Zhang, Henry Hu, Shen Xinwei, Jimi Tjong, Li Fang

With the demand for weight reduction in vehicles and airplanes, researchers have shown great interested in casting wrought aluminum alloy 7075 because of its potential advantages such as high strength-to-density ratio and stress-reduction capabilities. It is therefore essential to conduct a fundamental investigation on solidification behavior and grain microstructure of alloy 7075. In this study, a commercially-available wrought aluminum alloy 7075 was used to study the solidification behavior of alloy 7075. A thermal analysis was performed based on the cooling curve and its corresponding first and second derivative curves. The nucleation of the primary a-Al phase and eutectic phases were analyzed. The comparison between the microstructures of the wrought and cast 7075 alloys shows that coarse microstructure and porosity are present in the cast alloy. The techniques for grain refinement in casting, such as the addition of the nucleating particles and applied pressure, should be employed to reduce the dendrite arm spacing and the porosity.

Jan 1, 2015

By George J. Simandl, Donald F. Gunning

At the beginning of the 20 century, British Columbia produced a wide variety of quality dimension stone products for both domestic and foreign markets. The industry flourished until the 1930s when most of the producing quarries closed as a result of the Depression. During the 1990s, British Columbia experienced the resurgent North American dimensional stone production trend. The industry benefited from increased prospecting activity and from substantial new investment in processing equipment, particularly in the granite sector. These activities resulted in new quarry developments, the reopening of abandoned quarries such as on Granite and Fox Islands <www.quadrastone.com>, and a renaissance in downstream value-added activities. British Columbia has reestablished itself as an important, reliable and innovative source of high-quality stone products.

Jan 1, 2001

By G. A. Vissac

IN THE preliminary design of a coal washery, the most important factor to evaluate is the ash content of the final product. The ash content permissible may be imposed by market demands, but, in the final analysis, sooner or later - as most consumers today are buying coal on a &apos;heat value&apos; basis - the coal operator has a certain margin of latitude. and the ash content of the coal to be delivered can be determined on the basis of maximum returns and highest profits. A few years ago, the most desirable separation was selected on the basis of the plus-minus 0.10; that is, the most desirable gravity of the separation was selected at the point showing a minimum amount of near gravities in the raw coal. The reason for this was an expected wide error over these near gravities. Today with the recent development of cry accurate, automatically controlled cleaning apparatus, a much larger latitude is possible, and the most desirable gravity of separation can be selected, almost exclusively, on the basis of the economic factors involved. To illustrate these new methods of investigation we shall give two examples, based on actual coals from the western United States.

Jan 1, 1957

By Lawrence Nordell

A Conjugate Anvil-Hammer Mill (CAHM) has the potential to replace conventional crushers and SAG mills, with their respective conveyors and stockpiles, in a SABC circuit. It may improve comminution circuit efficiency by 100%. CAHM compresses rock in a more efficient way, similar to 19th century stamp mills, which follows the fundamental research of Schönert (1990 & 1996). CAHM efficiency is being proven through the use of ROCKY (2011) Discrete Element Method (DEM). ROCKY features allow it to simulate realistic comminution. CAHM is customizable with many geometries that are rock-property specific. ROCKY?s wear modeling compliments the structural integrity of the design.

Jan 1, 2012

By R. J. Enkin

Modern mineral exploration depends on multidisciplinary 3-dimensional integration of geological and geophysical data. Identification of the geological sources of geophysical anomalies requires knowledge of the physical properties fingerprint of rock types, formations and their alteration products. Understanding how and why rock physical properties vary within the Earth&apos;s subsurface ensures that appropriate geophysical exploration methods can be chosen, and allows for more efficient and effective surveys to be designed. Physical properties knowledge is integral to geophysical modeling - measured data or values estimated based on geological understanding are used to produce realistic forward calculations and to constrain inversion models. Mira Geoscience and the Geological Survey of Canada, in collaboration with industry and academia, are building a Rock Properties Database System (rpds.mirageoscience.com). It compiles the most valuable physical properties for mineral exploration (density, porosity, magnetic susceptibility and remanence, electrical resistivity and chargeability) linked with location and lithological metadata. A critical knowledge gap, addressed in this study, concerns the dependence of physical properties on alteration and mineralization processes. We report on the results of a collaborative University of British Columbia - Geoscience British Columbia project, ?Integrated Geological & Geophysical Porphyry Models: Adding Value to Geoscience BC Geophysical Data?. As part of the QUEST and QUEST-West geophysical initiatives, Geoscience BC focused detailed geophysical surveys on a suite of six known porphyry deposits: Mount Milligan, Endako, Huckleberry, Bell, Granisle, and Morrison. Physical properties for a set of 269 samples of characteristic host rocks and their altered equivalents were measured. The causes of physical properties variations were investigated through their correlations with ore and alteration mineralogy determined from thin-section observations and X-ray diffraction analyses. Physical properties of variably altered host-rocks and intrusive rocks vary significantly between different BC porphyry deposits. No specific unifying geophysical model exists that can be uniformly applied during exploration. Knowledge of local background geology and local physical properties variations is necessary as host-rocks and intrusive rock compositions vary depending on magmatic affinities, and alteration styles will vary reflecting host-rock compositions, crustal depth and influence of meteoric water. A district-scale exploration strategy requires location of intrusive bodies, which are commonly magnetic, resistive and low in density. Correlations should not be expected between density and magnetic susceptibility, because alteration may lead to magnetite destruction or to secondary magnetite development. Deposit-scale ground geophysics might image potassic alteration zones that can be magnetic in both alkalic and calcalkalic systems. Low magnetic susceptibilities, resistivities and densities might aid in locating the typically more porous phyllic and argillic zones. All geophysical data must be interpreted with background knowledge of local rock types and in light of the expected deposit model and associated magmatic and hydrothermal processes. The most effective means to building physical properties knowledge prior to geophysical investigation remains collecting rock physical properties measurements. The cost of rock properties data collection is low, relative to the overall costs of running a mineral exploration program, and can provide an important framework for design of geophysical surveys, survey method selection, geophysical modelling, and data interpretation.

Aug 1, 2013

By R. M. Kleine

In the fall of 1968, Sheridan Geophysics leased the Renzy Mine property 50 miles northwest of the town of Maniwaki, Quebec. A 500-tpd flotation mill was dismantled at Belleterre, Quebec, trucked into the mine over a winter road and re-erected during extreme winter conditions. Approximately one billion gallons of water were removed from Renzy lake to expose the orebody. A 3,000-hp diesel generating plant and a self-supporting community were set up during the early part of 1969. This was a remark-able achievement considering that most of the work, including the pouring of foundations and the draining of the lake, had to be done during the winter months. Despite this, the project was completed ahead of schedule and one million dollars below budget. The mill is now treating an average of 800 tpd.

Jan 1, 1970

By Lifeng Yang, Xiang Zhang, Liang Yuan, Yonghui Wang, Bing Hou, Mian Chen, Rixing Zhang

Large-scale hydraulic fracturing technique has been widely applied to the development of shale gas reservoirs, where the interaction between natural fractures and critical fracture zones has substantial impact on the propagation of hydraulic fractures. Therefore, it is of significant importance to understand and experimentally verify such mechanism. To reach this end, tri-axial fracturing tests were implemented on 400mm×400mm×400mm block samples collected from Longmaxi shale outcrops. The interplay between hydraulic and natural fractures was investigated during the tests, factoring in the role of pump rate in affecting the created fracture network. Based on the experimental results, the critical fracture zone, defined as the weak formation zone nearby the wellbore created by staged pressure implementation that is observed rapid fracture propagation upon next stage of pressure increase, was thoroughly investigated. The analysis illustrates that given the high brittleness of the shale formation, abundant critical fracture zones are generated around natural fractures with pressure building up at a relatively low pump rate. As the pump rate increases, hydraulic fractures initiate and come into play with critical fracture zones, implying emergence of a large number of micro-cracks. A changing pump rate modifies the way of interaction between hydraulic and natural fractures and the subsequent formation of fracture network. Long term fracturing fluid injection with relatively low pump rate below the activation of critical zones is suggested. Also proposed is appropriate timing when applying a specific pump rate that will contribute to the improvement of hydraulic fracture propagation.

Jan 1, 2015

By Frank S. Palkovits

Over the past 30 years, underground paste backfill systems have been implemented across the globe in many configurations, each with a primary focus of providing high quality backfill to enhance mine operations. However, a number of key design drivers are not always well understood within design engineering firms that occasionally undertake this work, leaving opportunities on the table. Perhaps not always obvious to those newly embracing paste technology, identifying key drivers and opportunities attainable through a paste backfill system is generally not straightforward, requiring innovative approaches to securing higher productivity, availability, performance, maintainability, and operator health and safety. This paper describes a number of applications and audits of paste backfill systems for several challenging mine operations. Key challenges include iterative design aspects of availability of good backfill materials, plant location and configuration, general arrangement, and binder receiving/storage systems.

Oct 1, 2010

By Rene Cane, V. I. Lakshmanan, John Starkey, Richard May

"The Agrium Kapuskasing Phosphate Operation mines and processes up to 6,000 t/d of phosphate ore. Run-of-mine crushing to minus 6 inches is done in a toothed roll-crusher, while grinding is done in a SAG/ball mill circuit with no coarse recycle classification of the SAG mill discharge. The primary grinding mill is an 18 ft. diameter x 9 ft. EGL, 1500 HP variable speed SAG mill and the secondary mill is a 13 ft. diameter x 21 ft. long, 2000 HP fixed speed, ball mill. When hard ore was treated, the SAG mill restricted the tonnage that could be ground. When soft ore was treated, the ball mill and spiral classifier overloaded and restricted throughput.Recommendations from a plant benchmark and an ore hardness testing program, on how to better utilize installed energy in the Agrium SAG mill when treating soft ore, and how to obtain best results when treating hard ore, were checked in a pilot plant investigation in the 3 ft. diameter Starkey-PRO Pilot SAG Mill. Correlation between the ore hardness testing and the results from the 3’ Pilot SAG mill was very good. In addition, the work indicated the results that could be expected for the different ore types when using either smaller SAG discharge grates and/or a vibrating screen with 10 mesh square opening cloth.INTRODUCTIONAgrium Kapuskasing Phosphate Operation consists of a 6800 t/d open pit mine and a concentrator, near the Town of Kapuskasing in Northern Ontario. The two major ore types are sandy ore and cemented ore. Sandy ore is fine, soft and easy to grind in the SAG mill while cemented ore is harder, more blocky and difficult to grind in the SAG mill. The ratio of sandy to cemented ore in the deposit is thought to be in the order of 80:20 but can range as high as 5050, so it was important for the grinding circuit to have the ability to treat sandy ore alone."

Jan 1, 2002

By J. E. Hawley

Introduction The Siscoe gold mine is the most easterly producer of gold from deposits lying in the belt of Keewatin and Timiskaniing rocks which extends east from Kirkland Lake, Ontario, and on through the Rouyn copper area. Unlike many of the deposits in this belt, those of Siscoe are contained almost entirely in a stock of much-altered granodiorite which intrudes Keewatin lavas. They are situated on an island of about one square mile in area, lying in lake De Montigny, Dubuisson township, 40 miles south of Amos, on the Transcontinental branch of the Canadian National railways, and 52 miles east, and slightly south, of Noranda. Geographically, the deposits are favour-ably situated with respect to transportation facilities, a through water-route being available from Amos, along the Harricana river and its lake expansions. The deposits consist of auriferous quartz-tourmaline veins of the fissure-filled type and are of particular interest because of their geological structure and genesis. Furthermore, deposits of a similar type occur both in the Keewatin and in granodiorite bodies to the east, in Dubuisson, Bourlamaque, Pascalis, and Louvicourt townships, and it is hoped that the following discussion may be of some aid in the exploration work now being carried on throughout this general area.

Jan 1, 1932

By J. H. McKibbon

THE metallurgical industry has purchased more than sixty per cent of the industrial gas cleaning equipment installed in Canada. This includes cyclonic collectors, scrubbers, cloth filters and Cottrell Precipitators. These are the principal types of equipment which are used commercially for the cleaning of gases which result from the processing of iron, nickel, copper, lead, zinc, gold, gypsum and aluminum ores. The recovered dust, which usually contains metal values, is returned to the process. The cost of the equipment is thus economically justified. This is in contrast to other industries, such as those involving steam power generation, asbestos, cement and lime production, where, though dust collection equipment is extensively used, it is installed primarily for nuisance abatement. Communities are becoming more and more conscious of air pollution, new and more stringent legislation is being enacted, and, for other than economic reasons the smelting industry will eventually be required to install more efficient gas cleaning equipment. This paper

Jan 1, 1962

By W. H. S. McFarland

THE Yukon Consolidated Gold Corporation, Limited, a Canadian company, operates alluvial gold dredges in the Klondike goldfields of Yukon Territory. Its operations are of unique interest to Canadian mining as it is the only large-scale placer mining operation of this type in Canada. Its properties lie in the valley of the Klondike river and its tributaries, Bonanza, Hunker, Bear, Last Chance, and All Gold creeks, and in the valley of Indian river and its tributaries, Dominion, Gold Run, Sulphur, Eureka, Montana, and Quartz creeks. At the end of 1938, they consisted of 1,650 placer mining claims and 9 leases or concessions. They cover a belt with an area of approximately 1,000 square miles. This vast area covers in part claims which have been previously worked by other methods such as &apos;drift&apos; and &apos;open-cut&apos; mining, and areas which were too low grade for such methods. The ground held by the Company is not held in freehold but in the form of mining claims and mining leases granted by the Dominion Government under the provisions of the Yukon Placer Mining Act. Full-size creek claims are 500 feet in length by 1,000 feet on either side of the base-line. Hill and bench claims are 500 feet up and clown the valley and 1,000 feet at right angles to the valley. All claims are held on the basis of an annual renewal fee of $10 for each claim plus &apos;representation work&apos; of an assessed value of $200 per claim per annum. For the purpose of such representation work, claims may be &apos;grouped&apos;. This means that work done by one dredge is sufficient to &apos;represent&apos; a comparatively large block of claims. It is only in this way that it becomes possible to consider operations on a large scale over a term of years, for such operations would obviously be impossible on law-grade ground if representation work had to be done separately on each individual claim in each year.

Jan 1, 1939

By T. Banerjee, Y. Dumais, R. Lemire

"Agnico Eagle LaRonde produces over 300,000 ounces of gold annually, along with silver, zinc and copper by-products. The LaRonde plant consists of a conventional SAG and Ball mill circuit, followed by flotation. Load management is imperative for maintaining stability in grind size and ensuring consistency of the flotation feed. In flotation, the mass pull profiles of the cells and reagent dosage rates need to be managed to maximize recovery, while maintaining product quality. This is achieved by controlling the air, level and reagent addition set-points across the circuit. However, disturbances such as feed size distribution, ore hardness and mineralogy make it challenging to maintain efficient control using traditional control techniques. LaRonde therefore worked to develop a progressive control strategy, targeting stability and optimization. This started with a year-long instrumentation upgrade campaign, focusing on optimizing the performance and reliability of plant-wide instrumentation. The process was then optimized, leveraging AwaRE advanced controllers running in closed loop with PARC modules embedded within the PLC. The installation of 8 PFC cameras in flotation changed the flotation operation from a level and air control based strategy, to one that controls mass pull. This new control philosophy has allowed the plant to effectively manage mill load, improving grind size and providing increased throughput with better flotation performance.INTRODUCTION Background Since 2015, Agnico Eagle LaRonde has been conducting an optimization campaign to maximise the performance of plant assets leveraging instrumentation and control. The grinding and copper flotation circuits were identified as the areas having the greatest opportunities and value proposition for advanced control. A disciplined approach was followed to design and implement a progressive control solution to achieve operational excellence."

Jan 1, 2018

By B. K. Mishra, Avijit Biswal, B. C. Tripathy, Abhijeet Singh, K. Sanjay, T. Subbaiah

We studied theeffect of anode substrates such as pure lead (Pb), lead antimony (Pb-Sb), and lead-silver (Pb-Ag) on the structural and electrochemical properties of electrolytic manganese dioxide (EMD). X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and chemical analyses were used to determine the structural and chemical characteristics of the EMD samples. The charge-discharge profile was studied in 9 M KOH using a galvanostatic charge-discharge unit. In all the substrates the current efficiencies were more than 99% except with Pb-Sb where it was 90%. Results revealed the nature of the substrate strongly affected the morphology of the deposited material which in turn affected the electrochemical properties of the EMD samples. XRD analyses revealed that the nature of the anode did not affect the crystal structure of the deposited EMD and all the samples were predominantly ?-MnO2, which is electrochemically active for energy storage applications. The EMD deposited on lead substrate showed superior discharge capacity of 245 mAhg-1 when compared with other substrates.

Jan 1, 2014

By R. A. Nemchek

ABSTRACT Concentrator plant design has evolved from large numbers of small grinding mills to small numbers of large mills. Consequently, plant performance often hinges on the productivity of a single large semi-autogenous grinding mill. Industry attempts to address the grinding mills’ critical nature frequently result in specifications that can be made simpler, more economical, and better focused on the project’s goals. This paper surveys current specification writing practices and proposes an improved approach recognizing that product design, procurement, manufacturing, and quality are interrelated in a successful project. The lessons learned here can apply to all types of machinery specifications.

Jan 1, 2014

By K. M. Wild, C. D. Martin, F. Amann

"Argillaceous rock formations, in particular clay shales, are notorious for creating challenges in rock engineering. Due to their generally low hydraulic conductivity and their complete saturation in their natural state at depth, the behavior of clay shales is usually characterized by a strong hydro-mechanical coupling.This paper presents typical pore pressure responses monitored in different underground rock laboratories and explores alternative ways for their interpretation. The underpinning processes and their relevance are identified based on analytical and conceptual numerical models. Pore pressure monitoring data from Opalinus clay at the Mont Terri Underground laboratory, the Boom Clay at the Mol facility and the Callovo-Oxfordian clay in the Meuse/Haute–Marne URL show a similar pore-pressure response associated with stress changes accompanying tunnel construction although the tunnels were built in different rock types, at different locations, and under different in-situ conditions.The numerical analyses in this study shows that the pore pressure response around an excavation in low permeable clay shales may have different explanations. Pore pressure drops observed in the tunnel near field can theoretically be explained by both, a pure elastic response in an isotropic or anisotropic rock mass with an anisotropic stress state, or a inelastic response and related dilatancy. However, a comparison between the numerical models and the in-situ measurements revealed that the latter is more likely. This conclusion is justified by the observation that pore pressure drops occur significantly ahead of the tunnel face which is not the case in elastic numerical simulations. Pore pressure measurements in the far field, where failure processes are unlikely to occur, can only partly be explained by a linear poroelastic models. The introduction of an anisotropic material plays a key role in reproducing the responses, conceptually."

Jan 1, 2015

By V. G. Papangelakis, A. Dani

"Alkaline pressure oxidation, particularly in the presence of trona as additive, can be used to oxidize high carbonate refractory gold ores as it prevents the formation of CO2 in the autoclave. However, the presence of silica in the ore can lead to the encapsulation of pyrite due to the solubility of silica in alkaline solutions and its subsequent reprecipitation on the reacting pyrite surface, leading to the formation of a passive layer. This fundamental study investigates the chemical composition and thickness of the passive layer on a rotating pyrite disk using XPS and SEM, as a function of process conditions at 230°C, in an aqueous slurry containing silica sand, sodium carbonate and calcium carbonate under 100 psi of oxygen overpressure.INTRODUCTIONAlkaline pressure oxidation (POX) has been used successfully to treat high carbonate refractory gold ores, which contain carbonates in addition to sulphides, most notably at Mercur and Goldstrike mines operated by Barrick Gold. There are several advantages to using alkaline POX over its acid counterpart, especially due to high carbonate content. First, it eliminates the production of CO2 in the autoclave without resorting to pre-acidification, which allows for high oxygen utilization. Second, alkaline POX suppresses the formation of elemental sulphur and intermediate sulphur oxyanions (such as thiosulphates and dithionates), which reduce gold recovery. Third, the use of sodium hydroxide or salts prevents the formation of anhydrite scale by forming soluble sodium sulphate. Other advantages are the use of cheaper materials of construction and the formation of non-acidic residue that do not require further treatment prior to cyanidation (Thomas, 2005).Sodium carbonate in particular is a promising reagent for alkaline POX because it was shown to significantly accelerate the kinetics of pyrite oxidation by molecular oxygen, when compared to other reagents such as sodium hydroxide, sodium borate and calcium hydroxide. This has been attributed to the following factors: a) the faster oxidation kinetics of Fe2+-CO3 complexes compared to Fe2+ oxidation, b) the buffering effect of carbonate ions on the acidic pyrite surface, and c) the increased solubility of oxidizing Fe(III) species due to carbonate complexation (Caldeira, 2010)."

Jan 1, 2012

By F. J. A. van Ruitenbeek, M. Dalm

In the presented study test work was performed with near-infrared hyperspectral imagery (NIR-HI) on 36 ore samples from a South-American epithermal Au-Ag mine. The aim of the test work was to investigate if NIR-HI provides information about the alteration mineralogy of samples that can be used to predict their economic value. Mineral distribution maps were produced from the hyperspectral images by using correlation coefficients between the image pixels and a set of reference spectra. These maps showed that detection of mineralogy with NIR-HI can be used to distinguish; i) ore particles with low Au and Ag grades, ii) ore particles with high carbon contents, iii) ore particles with high sulphur contents.

Jan 1, 2015