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By D. Hu, L. Matzar, J. Hampton, M. Gutierrez

Nanodarcy permeability is common in many oil- and gas-bearing formations requiring unconventional stimulation technologies, such as hydraulic fracturing (HF), which can connect the isolated hydrocarbon-rich pores with a wellbore through induced fracture networks. Even though a dense induced fracture network is capable of accessing economic amounts of hydrocarbons, much of the rock between and very close to the fracture network is still un-accessed and contains extremely low permeability. Inducing fracture networks into brittle rock can create large amounts of micro failures in surrounding regions that are not connected to the wellbore, as can be seen in Fig. 1(a) from the very wide acoustic emissions (AEs) cloud associated with a narrow fracture generation. It is possible in certain types of rock to increase the effective matrix permeability in localized regions based on the damage associated with the surrounding hydraulic fractures and subsequent high stress concentrations along localized pre-existing potential failure zones. To study this problem, laboratory HF tests were performed at true-triaxial stress state in brittle crystalline rock while monitoring AEs. The AE associated with HF was analyzed for source parameters using the moment tensor inversion method called Simplified Green’s Functions for Moment Tensor Analysis (SiGMA). Using the moment tensor for each individual AE event, the mode of failure was determined. Crack slip directions and crack face normal directions were also found, along with the relative volume of individual micro failures as well as a damage parameter. The associated source parameters were used to classify differing regions of damage in the sample induced from HF and correlate these regions of differing damage to the effective drainage region. Shown in Fig. 1(b) is a near-wellbore (NWB) region that contained three times larger average relative volumetric deformation of individual tensile AE events than the average tensile AE event volume from the entire sample. Because of the large difference in micro fracture volumetric deformation for the NWB region compared to the entire sample, predictions of HF induced damage must be included in reservoir drainage predictions.

Jan 1, 2015

By Nelson Lawrence

An Electrical Risk Management/Inspection Program has been designed specifically for the mining sector in order to provide electrical code expertise and systemic gaps in electrical systems. Goals include improved safety and productivity, reduced injuries and help to enable businesses to better comply with the electrical codes and regulations that govern them. The Electrical Risk Management/Inspection Program is now recognized by some of the world?s largest mining organizations. Since June, 2001 these electrical safety advisory services have been available to underground and surface mine sites throughout Ontario and are now offered throughout Canada and around the globe. This program is also currently being applied to review new electrical installations for mine construction projects thus improving the safety and reliability of mine site electrical systems.

May 1, 2006

By T. Plikas, T. Porretta, M. Al-Dojayli, B. Pretorius, J. Woloshyn, H. Ghorbani

"Water-cooled ducts represent an integral part of high temperature off-gas systems in metallurgical processes. Typically, off-gas enters these ducts at significantly elevated temperatures; therefore, water cooling may be required to maintain the duct skin temperature within allowable design limits. These off-gases are typically of high mineral content that could lead to dust buildup, and there is a possibility of slag buildup / molten metal splashing. Therefore, dust cleaning provisions may be necessary in order to remove or minimize accretion on the duct wall, which could otherwise impact the water cooling and the system process efficiency. These ducts may have complex geometry and experience a wide range of loading, including gravity loads, water and gas pressures, cyclic thermal loading and dynamic impact forces. Consequently, the thermo-mechanical assessment of such water-cooled ducts is critical and requires consideration phenomena such as high temperature gradients, potential nucleate boiling, thermal ratcheting and fatigue failures. Such assessment is not comprehensively covered by design-by-rule design codes and guidelines due to its complexity. This paper presents a successful implementation example of design-by-analysis methodology to improve the design and extend the life of a water-cooled furnace transition duct using Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA).INTRODUCTION Water-cooling represents an important part of high temperature off-gas systems in metallurgical processes. Typical temperatures of the off-gas in the furnace uptake are in excess of 1400°C, and thus there is a need to maintain the water-cooled duct and jacket skin temperatures within their material allowable design limits. Water-cooled channels have been used effectively in arc furnace roof design (Sosonkin et al., 1972; Smolyarenko and Khainson, 1988) and other furnaces as well as in furnace fuming jackets (Scholey et al., 1994). The design of these systems was based on one-dimensional analysis to ensure sufficient cooling is available under extreme furnace conditions (Smolyarenko and Khainson, 1988; Scholey et al., 1994). With advancement in furnace and fuming system designs, water-cooled duct designs have become more complicated in geometry. Numerical techniques, such as three-dimensional fluid flow and heat transfer modeling, are therefore needed to more accurately calculate water velocity, temperature and convective heat transfer coefficients in the water-cooled channels (Haywood et al., 2002; Henning et al., 2010). This is of particular importance around geometric corners where stagnant water flow may lead to local nucleate boiling at the critical heat flux, causing hot spots (Bergman et al., 2011). High wall skin temperatures increase the risk of failures due to thermal stresses as well as increasing corrosion rates (Gelfi et al., 2012), leading to costly equipment downtime and potential safety risks."

Jan 1, 2017

By V Dolmage

In 1957 and 1958, ten topographically suitable damsites were investigated along the Peace river between Finlay Forks and Hudson Hope, B.C. Of these, three were eliminated after a reconnaissance survey indicated that the geology was unsuitable for the 650-ft.-high dam contemplated. ?After extensive drilling, five other sites were deemed unfeasible because of geological factors and, in 1959, the two remaining sites were designated as being suitable, one for the high dam and the other for a low dam downstream. The sites are located in the Peace River canyon, on the west and the south? side of Portage mountain, west of Hudson Hope. The site for the large dam, the Portage Mountain dam, has since been investigated by surface mapping, thousands of feet of diamond drilling, a seismic survey, laboratory rock tests and on-site grouting tests in order to establish the possible effect on the dam of all facets of the foundation rocks. Three diversion tunnels, 50 ft. in diameter and 2,200 feet in length, have been driven through massive sandstone and shale, and an intake cut, 500 ft. in length, 200 feet in width and 200 feet in depth, has also been excavated in rock.

Jan 1, 1963

"The success or failure of coal mining operations in Western Canada may hinge on the ability to extract thick coal under a variety of geological and mining circumstances and conditions. The paper presents, in who-where, what- how pattern, the current status of undergrounud mining of thick coal seams based on a review of foreign technical literature. The underground production of coal from what are considered to be thick seams is over 300 million tons per year. Methods of mining have evolved, through years of trials and tribulations, capable of meeting the requirements of a modern mine: high bulk outputs from a limited number of mining faces by concentrating in the horizontal (mechanization) and in the vertical (increased working lift)."

Jan 1, 1972

By Jr. Jones

This paper is derived from a document that compiles autogenous and semi-autogenous mill installations worldwide, through the end of 2010. Updates have been solicited from all major mill manufacturers and most have responded. A review of AG/SAG mills sold to date and in the last five years indicates that the AG/SAG mill market is very healthy and the trend is larger diameter mills with high diameter-to-length ratios. Ring motors (gearless) are the preferred drives for large mills even though the power transmitted through a gear drive is expected to near 11,000 kW per pinion in the near future.

Jan 1, 2012

By F. R. Archibald

SINCE the opening of the Beattie mine, in 1933, the concentrate produced by flotation has been considered refractory. As the gold extraction by cyanidation was poor, the concentrate, during the first four and a half years of operation, was shipped to a smelter for further treatment. After the installation of the cyanide plant, in 1934, seventy per cent of the gold in the concentrate was recovered before shipment to the smelter. In 1937, a roasting plant was built so that treatment might be complete at the mine. Much experimental work had been done by a number of investigators prior to the installation of the roasters, but none of them had seriously attempted to identify the causes of, or the elements responsible for, the refractory behaviour of the concentrate. Intensive investigation in this direction commenced in the Beattie lab-oratory in July, 1938, has led not only to the identification of several causes contributory to the refractory behaviour, but also to revisions in procedure and principles with respect to roasting Beattie concentrate in particular and arsenical concentrates in general. The accuracy of the identification of these causes and the soundness of the principles is borne out by interpretation of roasting plant records, by improvements and simplification since applied. to plant operation, and also by laboratory and test-plant results on arsenical concentrate produced by another mine. It is the purpose here to present an account and interpretation of the laboratory investigation, together with a correlation of laboratory and plant results. Incomplete extraction of the gold by cyanidation after roasting is due primarily to the nature of the material roasted, and secondarily to the manner in which it has been roasted. There is a possibility that better extraction may be obtained by improvements in both particulars.

Jan 1, 1939

By G. B. Harris

In recent years, increasing attention has been focused on the hydrometallurgical treatment of base metals feeds, especially nickel laterites and polymetallic sulphides. One approach that has received some attention is the use of high?concentration chloride solutions (brines), which are now showing some promise after initial setbacks. Iron is usually the major component in the base metal feed to such processes, and if physical means cannot be used to remove it, then the iron concentration in the pregnant leach solution is always significant. This paper presents some of the background theory on the hydrolysis of iron in high-strength (>3M) chloride brines, and discusses the roles of temperature, solution concentration and free acidity. It is shown that the system is complex, but that crystalline and readily-filterable hematite can be generated, and that the system has a low energy requirement.

Jan 1, 2006

By R. Thierbach, W. Kahnt, Oberthür. T., D. Eisenburger, V. Gundelach

ABSTRACT: The ground penetrating radar (GPR) method was used in a platinum mine in Zimbabwe by members of the Federal Institute for Geosciences and Mineral Resources (BGR). The measurements were carried out in boreholes and drifts. Electromagnetic re?ections from a fault that consistently trends parallel to the mineralization zone permitted the mapping of the economically minable parts of the deposit. An introduction is given to the geology of the studied area and the application of the GPR method. The electrical parametres of the rocks are measured in situ, the GPR measurements are displayed with radargrams, and the visible structures are explained in illustrations.

Jan 1, 2010

By F. R. Nogas

"Because of the elements of uncertainty and instabilitp associated with single-enterprise communities, there is increasing interest in the alternatives to developing additional new communities of this nature. Gulf Minerals Canada Limited has chosen a unique alternative means to accommodate employees at a new uranium mine/mill complex at Rabbit Lake in Northern Saskatchewan. Gulf has adopted a fly-in program which moves their staff from a 450-mile radius, in and out of the on-site facilities, on a 7-day rotation."

Jan 1, 1976

By R. D. Brown

"Finance Minister Donald Macdonald's budget of May 25, 1976 featured a restructuring of the anti-inflation profit controls and a grab bag of tax changes, some of direct interest to the mining industry. All Canadian taxpayers now will be permitted to write off immediately 100% of mineral and oil and gas exploration expenses included after• May 25, 1976 and before July 1 1979. The cost of acquitting Canadian resource property after May 6, 197.4 from a federal or provincial government will now clearly be included in Canadian development expense, and provincial drilling and exploration incentives received after May 25, 1976 will not reduce exploration and development expense for federal income tax purposes. Under tough new anti-inflation profit controls, all controlled businesses, except distributions, will essentially have one uniform set of rules for• determining allowable profit margins; this allowable margin will be determined by product line or by over-all net margin and will be 85% of the higher of the margin obtained in the five years preceding October• 13, 1975 or the one year preceding May 1, 1976. The basic capital cost allowance system is to continue, but many rates will be revised. The ability to offset losses created through claiming capital cost allowances on leased equipment, etc. against other income will be ended with respect to transactions entered into a/te1• budget night. Miscellaneous other tax changes will raise the low rate base for Canadian-controlled private corporations to $750,000 increase retitement plan contribution limits and reduce the rate of branch tax imposed on branches of corporations resident in a country with which Canada has a comprehensive tax treaty to equal the withholding tax rate on dividends under that treaty."

Jan 1, 1976

By Sean Junor

Cameco Corporation ?One of the world?s largest producers of uranium ?Operations in Saskatchewan, Ontario, the United States and Kazakhstan ?Development projects in Australia ?One of the best employers for Aboriginal Canadians Geographic location ?Remote or northern operations ?Northern Saskatchewan ?Residents of Saskatchewan?s north (RSN) ?Wyoming ?Nebraska

May 1, 2010

By K. Chotruangprasert

This paper explores Global Reporting Initiative (GRI) reporting practices within the mining industry. Specifically, this paper investigates how and why a mining company makes voluntary reporting decisions to include the GRI indicators that may be considered ?negative? to the company?s reputation. Due to the voluntary nature of the GRI Guidelines, a GRI adopter is not legally obligated to report every GRI indicator. Not surprisingly, empirical studies that evaluated the extent to which companies? sustainability reports meet the GRI requirements (Guenther, Hoppe, & Poser, 2006; Morhardt, Baird, & Freeman, 2002; Samy, Odemilin, & Bampton, 2010; Skouloudis, Evangelinos, & Kourmousis, 2009) have found that reporting practices of the companies under their studies are well below the standards reflected in the GRI Guidelines. An influential study by Clarkson et al (2008) uses economic-based and socio-political theories to explain variation in companies? environmental disclosure. They have found that, as predicted by economic-based theory, superior environmental performers disclosed more ?hard? (i.e. verifiable) environmental information. Inferior environmental performers are found to disclose more ?soft? (i.e., not easily verifiable) claims, which is consistent with socio-political theories (Clarkson, Li, Richardson, & Vasvari, 2008). However, this study and the existing literature do not adequately explain why a company may act in a way that cannot be explained by economic-based and socio-political theories, for example, why it would report some negative soft data that it is not required to report. This paper intends to address this literature gap. GRI reporting by a Canadian mining company, which I would like to call ?Company C?, is used as a case study for this paper. Company C was selected for this research because in addition to ?positive? information, its GRI-based sustainability report also includes both hard and soft ?negative? information such as grievances. Research methods include interviewing Company C?s employees who are involved in preparing GRI reports and reviewing documents prepared both by the company and by external parties. I find that integrative social contracts theory (ISCT) offers a valuable explanation to Company C?s reporting practices. From the ISCT perspective, Company C?s management appears to feel that the company is obligated under social contracts to be transparent. Therefore, Company C disclosed both positive and negative social and environmental information to the public because the management appeared to think that it is the right thing to do. At the same time, being transparent about the bad news gave the company an opportunity to conclude that it had done something to avoid future occurrence of the negative incidents. Therefore, I propose that, in addition to the economic and socio-political theories that are more often used in literature, insights from ISCT are instrumental in improving our understanding of the corporate non-financial reporting practices phenomenon.

Aug 1, 2013

By Jr. Blanchette, Claude Bazin, Paul Blatter

"Reporting of the gold production during a month implies to estimate the mass of gold that is processed by a mill, recovered as dorés, lost to the tailings and the change of gold inventory within the plant equipments. Carbon in pulp and/or carbon in leach tanks may contain gold inventory as large as 72 000 g (2 200 troy oz) of gold which needs to be estimated from measurements obtained from sampling the material contained in a tank. Sampling and analysis introduce measurement errors that could be systematic and/or random. This paper examines the effect of measurement errors on the estimation of the gold inventory and on the variation of the inventory in the carbon in leach tanks of the Agnico-Eagle Mines Limited Lapa concentrator. Results of the analysis demonstrate that the inventory is measured with ±10% reproducibility, while the variation of inventory used for mass balance is known with ±300% reproducibility.INTRODUCTIONThe preparation of a production report implies to reconcile measured data with the constraint of material balance over the considered period of production. The sampling and data reconciliation problems were recently reviewed by Morrison (2008) and Jansen (2009a; 2009b). Typically a production report is prepared to cover a period over which the mass conservation hypothesis can be considered valid. In gold processing plants, the change of inventory can seldom be neglected and plays a significant role in material balance calculations. This is particularly true for circuits using carbon adsorption, where the complete cycle of carbon is measured in days.In a 2000 t/d gold ore processing plant, the inventory can be as large as 140 000 g of gold in gravity concentrator bins, carbon in pulp tanks and in the electrolysis circuit. This is equivalent to the mass of gold that fed the circuit during 10 days of operation with 7 g/t feed assays. The change of inventory may therefore strongly impact the production figures and especially the plant recovery at the end of a week or a month. Despite the financial impact associated with gold inventory, few publications are devoted to the subject. Bruington (1991) and Morrison (2008) discussed the problem and stressed the need for the development of reliable methods to estimate the gold inventory in carbon in pulp or carbon in leach circuits."

Jan 1, 2011

By A. Haldar

The major problem encountered in the casting of hypereutectic Al-Si alloys is the stoppage of flow below the rigidity level of solid fraction. In this study, the flow stoppage mechanism was studied using three Al-Si alloys with 14%, 18% and 22% silicon. The horizontal foam patterns used were 12.50 mm (0.50 inch) wide with two section thicknesses 12.50 mm (0.50 inch) and 6.25 mm (0.25 inch) with a common sprue. The primary silicon distribution along the length of the casting was studied to determine the mechanism of flow stoppage. It was found that the surface of the flow tip of Al-14%Si alloy was smooth with a few undulations. As the silicon level increased, undulations at the flow tip increased. The number and size of undulations were maximum for the Al-22%Si alloy. Microstructural analysis using optical image analyzer revealed that the flow tip consisted mainly of eutectic silicon in the aluminum matrix and a few primary silicon crystals (PSC). The PSC were in the interlocked condition few centimeters behind the flow tip. It was also found that the gap between the flow tip and the PSC concentrated area increased with an increase in silicon level. Phase characterization was done with SEM-EDX to identify the precipitating phases.

Jan 1, 2007

By M. Bouchard et G. Martineau

In the Chibougamau area, a large portion of the glacially tranported boulders which were deposited at the surface were later partly remobilized by the waters of Glacial Lake Ojibway. In the dispersal studies of these boulders, it is sometimes difficult to discern the effect of this reworking process. In addition, depositional processes in the lake contributed material to the original block deposits through the formation of boulder lag by littoral wave action and through direct sedimentation in the form of deltaic deposits. In spite of these complicating factors, dispersal studies at carefully selected sites which were unaffected by the above processes make it possible to unravel the general patern of glacial dispersion. In this study, indicator lithologies of the Albanel and Chibougamau formations were used. They give a coherent image of dispersal throughout the area showing transport toward the southwest. Considering the particular geological context of the region, and in view of the extensive mineral exploration studies which are being carried out, the results of this study are encouraging for the tracing of source areas of glacially transported mineralized boulders.

Jan 1, 1984

By A. Aaltonen, S. Paloranta, H. Myllykangas

A property based dynamic model of flotation was built and validated for training purposes. The model is based on the work of the AMIRA P9 project. The recovery of each particle with composition and size is calculated in a given simulation step. The model takes into account machine and operational parameters such as air flowrate and froth height. The model was created using fullscale test data on Pyhlisalmi Cu-Zn-pyrite ore with flotation kinetics of multiphase particles determined. Simulation and validation shows that model can predict the dynamic behavior of the process accurately enough for training purposes.

Jan 1, 2009

By Jesús L. Valenzuela, José R. Parga, Salvador Aguayo, Héctor Moreno

The Merrill Crowe zinc-precipitation process has been applied worldwide on a large number of operations for the recovery of gold and silver resulting in a higher consumption of zinc dust from cyanide solutions. However, in some of plants this precipitate is of low quality, because lead, cadmium and especially copper are precipitated along with gold and silver. The low quality precipitate also requires more fluxes in smelting and shortens crucible life. In this study, a process is introduced to remove copper, silver, lead and cadmium from barren solutions following the Merrill-Crowe process. Copper and silver are removed by precipitation in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. The recovery of lead and cadmium ions with natural hydroxyapatite using cow bone powder (CBP) as a new adsorbent material, is introduced. CBP is capable of removing lead and cadmium ions from aqueous cyanide solutions with 99% efficiency. It has the ability to compete with other existing commercial adsorbents for the removal of lead and cadmium. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 99 %; and for the cyanide associated with copper cyanide complexes, the recovery was 90%. Finally, the precipitate quality was improved 400% .This procedure was successfully run at three mines in México.

Jan 1, 2014

By W. J. Dick, K. G. Kress

A pipeline syphon can be a simple and reliable alternative for water conveyance as compared to otherwise more complex pumping systems or low-level outlet conduits through earthfill dams. In a simple form, it consists of a pipeline constructed over the top of a dam or other high topographic feature, connecting a source pond to a receiving pond or channel (Fig. 1). The syphon action is initiated by removing air from the pipeline (priming) using water pumps, vacuum trucks, or simple devices that can be purchased “off-the-shelf.” Once primed, the syphon flow rate can be controlled or stopped using conventional gate, valve, orifice plate, or other devices. Repriming is not required even if the flow is stopped, provided the syphon was not drained. A limiting factor in considering a pipeline syphon as a design option is the maximum lift (i.e. vertical distance from source pond water level to summit of pipeline syphon) which is approximately 9 m or less, depending on pipeline syphon features and site conditions. A pipeline syphon can be quickly constructed from readily available materials including steel, concrete, polyethylene, or PVC pipe. It is particularly well suited to many of the unique conditions often encountered at mine sites. This paper identifies situations that can sometimes be best resolved using a pipeline syphon. It provides basic principles for pipeline syphon design and includes case histories of their successful application.

Jan 1, 2005

By M. Turner-Jones, N. Steenekamp

"The Lonmin Base Metal Refinery treats converter matte from the Lonmin Smelter to produce nickel sulphate crystals, copper cathode as well as a concentrate containing the platinum group (PGM) metals. The original process employed a Sherritt design and utilizes atmospheric and pressure leaches for the dissolution of base metals. This paper describes the original flow sheet and the improvements made to enhance PGM recoveries, product quality and to increase capacity. Changes include the introduction of flash recycle cooling on the autoclave, batch leaches to improve the quality of the PGM concentrate and the implementation of solid-liquid separation with centrifuges. INTRODUCTIONThe Lonmin Base Metal Refinery (BMR) is about 100 km north-west of Johannesburg and treats converter matte from the Lonmin Smelter to produce nickel sulphate crystals, copper cathode and a concentrate containing the PGMs. The plant was commissioned in 1985 based on a Sherritt design to treat 12 tonnes converter matte per day. The original flow sheet consists of a milling circuit, an atmospheric leach and a pressure leach to produce a PGM concentrate which is despatched by helicopter to the Lonmin Platinum refinery in Brakpan, about 40 km east of Johannesburg. The liquor from the atmospheric leach is treated by crystallization to produce a nickel sulphate hexa-hydrate crystal. The leach liquor from the pressure leach is treated by a selenium removal step followed by electro-winning to produce copper cathode. The spent solution from the copper electro-winning is recycled to both the atmospheric and pressure leach steps to provide sulphuric acid for the leaching reactions.Modifications were made to the original circuit to increase the plant capacity, to improve the PGM recoveries and to improve the quality of the PGM concentrate. Capacity increases included all the unit operations, new mill, new first stage, additional autoclaves, additional nickel sulphate crystallizers, new copper electro-winning and new batch leach reactors for upgrading the PGM concentrate. The current circuit is described in this paper and not the detailed history of each plant change."

Jan 1, 2012