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By S. C. Cohen, A. F. Mikkelsen

"This paper describes the improvements made to the operation of a liquid phase, 300°C, heat transfer system in the paste plant of an aluminum smelter. These improvements were achieved by replacing the original heat transfer fluid, a synthetic aromatic, with a new technology, petroleum-based product. This new fluid, Calflo HTF, provided better thermal stability, with lower toxicity, and improved plant working conditions.The procedures for fluid selection, changeout and performance monitoring are described along with a summary of control analysis over the last three years."

Jan 1, 1993

By Dwayne D. Tannant

The Fox Pit at EKATI Diamond Mine reached a depth of approximately 150 m as of September 2005. The pit is designed with 11 m wide benches excavated using a double benching technique leaving 30 m high bench faces. A series of blasting tests were conducted to improve catch bench reliability and increase the percentage of benches that meet an 11 m catch width. The design changes focussed on reducing damage to the bench crest because maintaining the bench crests is the most important factor in achieving good bench reliability. The most significant improvement was obtained by raising the bottoms of the lower trim blastholes by 0.5 m. This change decreases the depth of broken rock below the final bench elevation, and consequently reduces damage to rock that forms the bench crest below. Another improvement was the use of smaller diameter (165 mm vs. 270 mm) blastholes in the A and B rows for the upper trim blast. This change reduces the charge per delay during detonation, reduces the powder factor slightly, and reduces the energy affecting the final pit wall and crest. As mining and the blast testing progressed, the portion of the bench with crest achievements (>11 m) increased from 57% to 75%.

May 1, 2006

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 I. I. Bethcherman

Introduction 1.-lmportance of Physical Nature of Condensates The metals of commercial interest which have reasonably high vapour pressures below 1,200° C. are mercury, cadmium, sodium, zinc, magnesium, lithium, and calcium. With the exception of mercury, these metals occupy high positions on the electrochemical series and form compounds with very high negative free-energies of formation. It is highly desirable that such metals should not be produced in a form which is finely divided, on account of their reactivity with atmospheric gases. Powders of magnesium, calcium, and even zinc (blue powder) are dangerous to handle and cannot be coalesced by simple melting techniques. Vaporization in vacuo forms a convenient method of handling and purifying the alkaline earth metals in particular and a previous paper by the authors dealt with some of the factors controlling the separation of metals by this technique (12). An essential part of the operation is the condensation of the vapour to produce a massive deposit which may be conveniently melted and handled by established metallurgical techniques. This investigation sought to determine the conditions affecting the nature of solid condensates.

Jan 1, 1951

By Mohammad. M. Khajeh

Rock mechanical properties are important parameters in geomechanical simulation. Considering stochastic heterogeneous models rather than conventional homogeneous layer cake models leads to more realistic simulation results and uncertainty assessment. These heterogeneous models are usually fine scale models generated by geostatistical techniques. Although considering high resolution property models is desirable, geomechanical simulation with a fine scale model is not computationally feasible for full?field, coupled geomechanical-flow simulation. Upscaling of property models is necessary to move from fine scale/high resolution property models to coarser scale/low resolution models appropriate for simulation. Local numerical upscaling was proposed by Khajeh et al. (2012) to describe the macroscopic elastic behavior of complex heterogeneous media and is expanded upon in this work. This numerical technique is not restricted to specific geologies as typical analytical techniques are. Moreover, transversely isotropic deformation is considered rather than the usual assumption of isotropic deformation. To compare the accuracy of the upscaling methodology, in this study shear strain is considered as the geomechanical response of a synthetic facies model and the response of the coarse scale model is compared to other conventional analytical averaging techniques. It is found that the numerical upscaling technique better approximates the geomechanical response of the fine scale model.

Jun 1, 2012

By S. Esmaeili

The yield strength model developed by Esmaeili, Lloyd and Poole [1] has been adapted to model isothermal aging in Cu-containing AA6xxx alloys, with (a) a moderate and (b) a very low Cu content in the solution-treated, as-quenched, condition, Isothermal calorimetry has been used to analyze the kinetics of precipitation in these alloys, While the kinetic parameters for the low Cu alloy has been derived from the present experiments, the previously determined kinetic parameters for the high Cu alloy AA6111 has been used to model the precipitation kinetics in the moderate Cu alloy. The age hardening responses of both alloys have been well predicted by the model.

Jan 1, 2005

By B. S. W. Buffam

"The property of Aunor Gold Mines, Limited, is in Deloro township, Ontario, about 3 miles southeast of Timmins. It consists of a group of eleven claims between the Buffalo Ankerite and Delnite mines.In the autumn of 1909, two brothers, John A. and W. S. Mitchell, joined the 'gold rush' to Porcupine. By the time they arrived the township of Tisdale, in which the Hollinger and Dome discoveries had been made, was staked solid but they managed to locate four claims in the northern part of Deloro township. Sufficient surface work was performed to bring the claims to patent in 1915. Following the Porcupine fire the Mitchells left the north to follow the oil developments in southwestern United States. In 1935 because of the rise in the price of gold and the successful development of the l3uffalo Ankerite and Delnite mines, they returned to Timmins and organized Augite Porcupine Mines, Limited, which combined the original four claims in Deloro and two adjoining claims controlled by Montreal River International Silver Mines, Limited. There were few rock exposures on the property, and as the overburden was generally deep surface exploration was impracticable. A programme of diamond drilling was, there; fore, undertaken in an endeavour to locate the western extension of the orebearing formation of the Buffalo Ankerite mine. This drilling was started in August 1936, and 5 months later ore was intersected at a depth of 500 feet on the south boundary of the property."

Jan 1, 1954

By M. G. Lipsett

General Challenges for Mining & Mineral Processing Operations ? Capital-intensive industry ? Ongoing cost pressures ? Remote locations ? Workforce demographics ? Dynamic, unstructured, rugged environment

May 1, 2008

By D. T. Aikens, R. Gaudreault

"This paper summarizes structural repairs carried out on a marine wharf consisting of six 13.7 m by 13.7 m reinforced concrete cribs linked together by five 14.6 m long beam spans. As a result of problems during original construction and twenty years exposure to severe weather conditions, the deck support system between the cribs required major restoration work. In particular, some of the beam seats under the crane rail supports had marginal bearing area to support the structural loads. Faced with closure order for the wharf which is required to bring in raw materials to the plant and a long outage to make repairs as stipulated by Ports Canada (owners of the structure) alternate means of making the required repair were examined.The method chosen allowed the work to be done much more quickly, at lower cost, without taking the wharf completely out of service. The badly deteriorated seats were rebuilt using epoxy grout, tapered sole plates and a positioning jig."

Jan 1, 1988

By K. P. Plucknett, Z. Memarrashidi

WC-Co ‘hard metals’ are widely used in a variety of industrial applications due to their resistance to abrasive wear, in addition to their high hardness and toughness. However, in contrast to their mechanical properties, the corrosion response of these materials is relatively poor. In the current work the corrosion mechanisms of two WC-Co cermets are analysed, with 10 and 30 vol. % of the Co metal binder, in a 3.5 wt.% NaCl aqueous solution. The assessment of corrosion involved a variety of electrochemical measurements, including open circuit potential, potentiodynamic polarisation and cyclic polarisation, together with systematic analysis of the post-corrosion solution chemistries using inductively coupled plasma optical emission spectroscopy. The corrosion potential and current density were determined, following Tafel extrapolation, allowing the calculation of the corrosion rates. It is demonstrated that continuous dissolution of the cobalt phase occurs during corrosion, which is a result of poor cermet passivation behaviour, and this response increases with the amount of binder in the cermet.

Jan 1, 2015

By Janice Zinck, Ian London

In recent years, the secure supply of critical and technology metals has become increasingly important tomajor industrialized economies that seek to sustain their industrial base and develop advanced technologies, such as clean energy. Canada, with its significant reserves of rare earth element (REE) and other metals, has an opportunity to supply some of the global demand for these materials. However, to transition from promising mineral deposits to marketable products, investment in strategic research and development (R&D) and expertise is needed to address the complex technological challenges around the production, separation and processing of these metals, and to better understand the global market for these key commodities. To this end, in its April 2015 budget, the Government of Canada committed to invest $23M over 5 years to accelerate production of REE and chromite/ferrochrome. The goal of this program, developed in close association with industry, is that Canada contributes a sustainable supply of REE to the global market. The research and development program will provide the technological capacity to establish a Canadian REE industry. This paper will discuss REE R&D advances achieved in the first year of the program in areas of mineral characterization, beneficiation, leaching, separation and environmental management and will highlight the Canadian model of collaboration where industry (e.g. prospective producers, technology companies), government, academia and other stakeholders work closely to ensure that the R&D is targeted, innovative and effectively deployed and commercialized.

Jan 1, 2016

By Gerhard Kircbner, Boen Tan

"IntroductionThe Key Lake uranium-nickel ore deposits are located in the Athabasca Basin of northern Saskatchewan, Canada (Fig. 1). Many papers have been published on Key Lake in the past (Dahlkarnp and Tan, 1977; Kirchner and Tan, 1977; Kirchner et al., 1980). Immediately after its incorporation in 1968, Uranerzbergbau GmbH, a German holding company, set up exploration subsidiaries in Australia, the United States and Canada. This account reviews those exciting years starting with the concept to explore the rim of the Athabasca Basin in Saskatchewan, and leading up to the discovery of the deposits in 1975 and 1976.A few summary statements can be made:• The discovery of Key Lake resulted from a very systematic exploration approach and the persistence of Uranerz, the operator. • Cluff Lake and Rabbit Lake had been discovered some seven years before, but it was the discovery of the Key Lake deposits which brought Saskatchewan to the forefront to become Canada's foremost uranium producing province.• The experiences gained at Key Lake, which were subsequently published, triggered the discovery of many other deposits of similar, or even larger, size than Key Lake. The spatial relationship of those deposits to graphitic conductors and hydrothermal alteration zones are presently the most effective indicators for locating new deposits - indicators which were first recognized at Key Lake.• Key Lake is, and will remain for some years to come, the largest producing high-grade uranium mine in the world."

Jan 1, 1994

By W. F. James

Introduction The season of 1927, from the point of view of mining development in the area west of Rouyn, was quite satisfactory. Serious prospecting and development' were undertaken over quite a large area, though the results in the matter of discovering new deposits of economic importance were rather disappointing. A large amount of systematic prospecting and geological mapping was carried out in the course of the work, and a considerable body of information collected. A widespread occurrence of sulphide mineralization was noted, chiefly near bodies of older gabbro. The frequent occurrence of pyrrhotite in or near which local concentrations of chalcopyrite were localized, lends support to the idea that such older sulphides as pyrite and pyrrhotite are relatively easy of replacement by chalcopyrite. From the prospector's viewpoint, areas near the contacts of masses of older gabbro are favourable prospecting ground, and pyrite and pyrrhotite mineralization are favourable indications that massive chalcopyrite may be found where it has completely replaced such sulphides. Pyrrhotite being magnetic is easily located, even where drift covered, by the use of such convenient instruments as the dip-needle and the magnetometer. It is suggested that pyrrhotite bodies, when located, be thoroughly prospected because of the fairly strong probability that they may show replacement by the more valuable chalcopyrite.

Jan 1, 1928

"Abstract - An estimation of resources of structurally complex gold lodes and stockworks represents a challenging task for geoscientists due to the complex geometry of the lodes and discontinuous grade. In the present case study, the resource of a gold stockwork has been estimated by uniform conditioning after the lode has been subdivided into geostatistically defined domains using the indicator probability model. The indicator probability model represents a powerful tool for structural interpretation of the mineralization and can be applied when traditional 3D volume constraining methods (wireframing) have failed to produce a unique, non-subjective model. For comparison, the resources of the same zone have been estimated without domaining. Results of the study clearly show that estimates obtained without domaining of the mineralization can yield a substantial error due to excessive smoothing of the grade.Application of uniform conditioning for modelling the grade distribution has a significant advantage over linear methods (e.g., ordinary kriging). Uniform conditioning enables estimation of local recoverable resources at different selective mining unit sizes that can be substantially smaller than the drilling density without creation of biases or over smoothed local values."

Jan 1, 2002

By Edgar L. Horner

"The objectives of the Wabush Mines tailings stabilization program are to control dust Ii/t-off and to rehabilitate the disposal area. The evolution of the program started with test plots in 1970, these being continued and expanded upon through 1974. In 1976, a 35-acre vegetation field trial was attempted and failed, part of the failure being attributed to lack of adequate equipment. Subsequently, equipment was purchased and during the summer of 1979-80 extensive areas were treated. The program was also expanded to include the evaluation of chemical and water spray stabilization versus vegetation in areas where shorter-term control is required. In addition, during the summers of 1979-80, spruce bog material was spread over about 100 acres and seeded.The approach to reclamation by vegetation at Wabush is one of soil building. Work to this point indicates that iron ore tailings can be converted to a soil capable of supporting plants. Plans for the Wabush tailings disposal area should make dust lift-off from inactive tailings areas negligible within the next few years."

Jan 1, 1981

By Michael S. Moats, Addin Pranowo, Gerardo R. F. Alvear F., Nigel Aslin

The toxicity of arsenic is well known and documented. However, the presence of arsenic in copper electrorefining anodes and electrolyte is critically necessary to produce high quality cathode. Arsenic as well as antimony and bismuth concentrations vary depending on their relative concentration in the anode copper received from the smelter. This paper will discuss the behaviour and benefits of arsenic in copper electrorefining and the detrimental effects of antimony and bismuth on cathode quality and tankhouse performance. This will include the minimization and mitigation of problems associated with arsenic, antimony and bismuth including cathode contamination, floating slimes, scaling and anode passivation.

Jan 1, 2014

By Sebastian Siebert

Unmanned Aerial Vehicles (UAV) as a data acquisition platform and as a measurement instrument have become attractive for many surveying applications in civil engineering. However, their performance is not well understood for these particular applications. The specific scope of the presented work is the performance evaluation of a UAV system that was built to rapidly acquire mobile 3D mapping data for large earthmoving construction sites. Details to the components of the developed system (hardware and control software) are explained. A novel program for photogrammetric flight planning and its execution for the generation of 3D point clouds from digital mobile images is explained. A performance model for estimating the position error was developed and tested in several realistic construction environments. Results to these tests are presented as they relate in particular to large excavation and earth moving construction sites. Results and experiences with the developed UAV system are in particular useful for researchers or practitioners in need for successfully adapting UAV technology for their application(s).

Aug 1, 2013

By David W. Mogk, Tamara Darsow, Macgregor L. Fogelsong, Robert M. Hunter, Frank M. Stewart, Edwin H. Abbott, Courtney A. Young

Abstract: Development of cost-effective techniques for recovering precious metals from their ores has been the goal of metallurgists for hundreds of years. Today, metallurgists are increasingly called upon to design processes for ores that are refractory to conventional recovery techniques. These challenges and the addition of environmental costs (including site remediation) to the total cost of mining have stimulated a search for alternatives to conventional processes, such as cyanidation. This paper describes the progress made to date in development of an innovative alternative to cyanidation, termed bisulfide leaching, for extracting gold, silver and platinum-group elements from refractory ores and concentrates. While bisulfide leaching can be implemented abiotically, significant benefits accrue from its practice as a bioprocess that integrates the steps of precious-metals liberation and extraction. In many applications, bisulfide leaching appears to offer significant advantages over the traditional cyanidation process. Dissolved bisulfide and hydrogen sulfide are much less toxic than dissolved cyanide and hydrogen cyanide. Recommended workspace exposure limits and harmful concentrations for hydrogen sulfide gas are higher than those for hydrogen cyanide gas. While the facilities required to practice the bioprocess on an industrial scale would be similar to that of cyanidation plants, chemical reagent costs could be 80 percent less. The bioprocess may also offer advantages in the leaching of ores and concentrates that are not amenable to cyanidation. For example, bisulfide leaching of ores containing carbonaceous material may produce higher gold recoveries if the "preg-robbing" characteristic of the material can be controlled biologically or with dissolved sulfide binding. Moreover, in that precious metals are much more soluble than base metals in bisulfide solutions, bisulfide leaching offers distinct advantages over cyanidation for selective dissolution of precious metals from base-metal concentrates. Thus, the bioprocess uses the natural sulfur cycle to mitigate pollutant production and to enhance precious-metals recovery.

Jan 1, 1998

By Navid Bahrani

Introduction ? Today?s economic market is motivating underground mining companies to increase development advance rates and enhance their NPVs. ? For example, block cave mining involves development of kilometers of drifts with multiple pillars. ? The cyclic nature of drill and blast, and its inherent tendency to damage the surrounding excavation rock mass and increase support demand often result in poor advance rates ? This has motivated mining companies to replace the conventional drill-and-blast as the main excavation method with alternative methods such as mechanized excavation. ? There is little experience with mechanized or non-explosive excavation methods in hard rock metalliferous underground mining.

Oct 1, 2010

By Zia Pirzada

"Time is of the essence" and "Time is money" These are powerful and true statements during a project life cycle and have far-reaching implications on the success and failure of the project Time and progress management is crucial to the project success. Project delays may increase the cost to an unacceptable level and may render the project as economically unfeasible. On the other hand, if the project is completed on time or earlier than as planned, it may generate economic benefits greater than what had been envisioned To take advantage of the financial opportunities and to improve the cash flow as well as Return On Investment (POI), project schedule can be accelerated to complete the project earlier than planned Project schedule acceleration can be achieved by using analytical tools, such as "Schedule Optimization", "Schedule Reduction", "Schedule Compression" or a combination of any of these concepts along with the "Planning for start up". Schedule optimization does not entail any extra cost, however, other acceleration methods, such as Schedule Reduction and Schedule Compression, may require extra expenditures from the owner. Based on the forecasted early start of the revenue stream, the extra expenditure could become a worthwhile venture with a very high rate of return To accelerate the schedule, all aspects of the project should be reviewed with acceleration costs calculated. All risks and opportunities should be evaluated and taken into consideration to determine if the acceleration is feasible and advisable and will provide definite financial advantages Sometimes schedule acceleration may be desired to prevent the company from paying liquidated damages. This is especially true when the project is not expected to complete on the contractual completion date and when the cost of acceleration is less than the liquidated damages that may accrue against the company.

Oct 1, 2010