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By David R. Lentz

At True Hill in southwestern New Brunswick, low-grade porphyry-style Bi-8n-Mo greisen mineralization is associated with the cupola of an epizonal granite porphyry (granite) that also exhibits three episodes of brecciation. The first episode of brecciation is an in situ, 8 m to 10 m wide transitional zone of net-veined to coarse-grained "blocky" endogranitic mesobreccia that is chloritized and greisenized and hosts weak disseminated minerali.zation. In a zone closer to the host rockgranite contact, angular fine- to coarse-grained endogranitic mesobreccia with greisenized matrix is superimposed on the earlier transitional breccia. The latest episode is fault-controlled and consists of quartz- and chalcedony-hosted sub-angular to rounded fine-grained "pebble" mesobreccias that crosscut and brecciate the other breccia types, as well as the adjacent altered metasedimentary country rocks. The first two episodes of brecciation are magmatic-hydrothermal in origin related to hydrofracturing of the granite carapace and are accompanied by greisenization and mineralization, whereas the post-mineralization, silica-hosted, "pebble" mesobreccias related to hydromagmatic, low-temperature fluid circulation and/or boiling along faults near the contact. These magrnatichydrothermal and hydromagrnatic mesobreccias are similar to those associated with W-Mo-Bi porphyry-greisen mineralization at the Mount Pleasant deposit.

Jan 1, 1994

By A. LA. Salama, D. B. Hyma

"The Western Research Centre (WRC) of CANMET located in Devon, Alberta, is a modern research facility offering services ranging from fundamental research to pilot plant investigations. Recently, a 0. 76 metre diameter by 7.9 metre high Flotaire column flotation cell was installed as a demonstration unit for Canadian coal producers. Because the column cell is intended to be used for research, development and demonstration, WRC recognized that additional sensing equipment and improved process control would be required to generate good data for subsequent column scale-up and engineering design.A low cost, personal computer based control system was, therefore, designed and installed. This paper describes the stepwise procedure in developing the control strategies, selection of system software and hardware, and installation and configuration of the system.Preliminary performance data on a western Canadian coal sample are also presented. Future testwork is planned on additional coal samples to expand upon existing database."

Jan 1, 1993

By C. Mills, A. O. Burt

"The paper examines the role of gravity concentration in both an historical context and within the modern mineral processing industry. It discusses the principles of the process on both a theoretical and practical level. The importance of more mineralogy and its effect on the choice of the wide range of equipment available is discussed. The paper concludes with a discussion on the relative merits of gravity concentration with other forms of processing.IntroductionIt is an unfortunate, albeit popular, misconception among otherwise enlightened engineers in the mineral processing industry that gravity concentration was a process developed in the dark ages, perfected in the middle ages, and abandoned in the modern ages.Gravity concentration was developed in the dark ages - long indeed before that. Agricolau: cited examples of gravity concentration, crude examples admittedly, being practiced over 3000 years ago. However, gravity concentration is not dead. Far from it. As recently as 1978 it was reported that the total mineral tonnage treated by this process in the United States was greater than that processed by flotation. Coal represents the bulk of the or e treated by gravity separation in the U.S.A., with iron ore representing a major portion of the balance."

Jan 1, 1985

By M. Fiset, D. Belley

"To better understand the wear process of various materials that may be used as blades on snow removal equipment, the first step is to evaluate the influence of the load applied and the moving speed on road wear rates of one type of steel and three types of polymers. While the behavior of steel conforms to Archard's law, wear rates of polymers increase to a power of ex of the load applied according to a model implying that the wear of these materials is due to fatigue. The wear rate of some of the polymers varies considerably in terms of speed, unlike the steel. The wear resistance of some of these polymers outclasses the steel tested as long as the speed is not too great. They, therefore, present interesting alternatives for snow removal on more fragile surfaces such as sidewalks and zone made of inter-block slabs.IntroductionSince the dawn of the Industrial Revolution, the massive use of machines has brought with it a number of different problems regarding wear. Snowplowing roads, parking lots and sidewalks is an activity that generates enormous expense in a country such as Canada. To better understand these wear processes and in the hope of stimulating new approaches designed to reduce the costs related to this sector of activity, this paper presents the behaviour of several materials (steel, polymer and rubber) as they wear on an asphalt-fines matrix surface lubricated with water. Also discussed is the effect of various parameters such as the load applied and speed."

Jan 1, 1990

By H. Henao, F. Canales

The present work evaluated the use of copper ore flotation tails as flux in the process of smelting copper concentrates. For this purpose, experimental and simulated liquidus lines were obtained at different ratios of tail/flux. Experimental variables included temperature, partial pressure of oxygen and sulfur dioxide and the conditions of tridymite or spinel saturation. The results indicate the feasibility of replacing the flux by increasing the temperature of the smelting process by 20°C. Results of simulation using FactSage and HSC confirm that the required increase in temperature can be achieved by increasing the flow of concentrate, enrichment of oxygen or increasing the matte grade. INTRODUCTION In the pyro-metallurgical process of copper production, the smelting stage produces two liquid phases, a sulphide phase rich in copper and another composed mainly of oxides called slag. The slag phase is the product of oxidation of the iron contained in the flotation concentrate. The smelting process which is carried out at temperatures of 1250°C, require the addition of silica as a flux and the injection of air enriched in oxygen (Schlesinger 2011). Currently, one of the most important aspects of the mining industry is the minimization of costs, the optimization of the use of available resources and the reduction of environmental impact. Under this context, the use of flotation tails from as a flux in the copper smelting process has the potential of reduced production costs and generate an environmental benefit by reduce the disposal amount of this waste material Regarding the use of copper tails as flux in the copper smelting process, a thermodynamic simulation study using the FactSage software had been reported in the literature (Parra et al., 2011). The results indicated an increase of 35°C in the temperature the liquidus for the equilibrium matte/spinel and a subsequent requirement of energy in the process of approximately 350 [MJ/ton slag]. Given that the calculated viscosity remains in the same order of magnitude, the melting temperature is a more relevant parameter for the evaluation of the use of tailings as flux.

Jan 1, 2019

By K. A. Hildebrant, J. R. Norgate

"Synthetic lubricants have for many years documented extended service life and provided superior performance in temperature extremes. Increasing interest in synthetics' ability to reduce energy costs has resulted in laboratory and industry application evaluations. These tests have documented savings in functions such as worm gear drives, spur gears and in compressors. Energy savings data are presented as well as payback calculations as low as thirty days.The National Research Council of Canada has estimated that the Canadian economy loses over five billion dollars per year in friction and wear. Figures quoted were for 1986 during which it was estimated that nine hundred and forty million dollars were lost in the mining industry alone"" It has been further estimated that about 115 million dollars can be immediately recovered through improved tribology practices (Table I).The purpose of this paper is to present results and savings opportunities through the use of synthetic lubricants in various but common applications. Many other areas exist with the opportunity for energy savings such as in the use of more efficient drive equipment, reduced contact seals, spray mist lubrication systems and reduced friction coatings on rotating equipment such as pump impellers"

Jan 1, 1994

By Ch. Enkhbold

Underground mining of minerals is becoming an increasingly complicated technological and ecological problem. It can be explained both by worsening of geological conditions of mining and by a specific character of mining industry, which, in contrast to processing branches of industry, intrudes into one of principal components of the nature ? the Earth's interior. At a traditional organization of mining industry, the entire volume of the produced rock mass is brought to the Earth's surface, where valuable components are extracted. This entails not only power over expenditure for long-distance transfer (especially in the vertical direction) of the waste rock forming a part of the original mineral, but also the formation of huge volumes of worked-out spaces. The latter leads (nature cannot stand emptiness!) to an irreversible development of geomechanical processes of shifting of overlying rock masses resulting in an irreparable damage of all surface structures located on the territory undermined by deep mining. Owing to their high productivity combined with low power consumption and instrumental compactness, novel bifunctional technological processes of minerals dressing successfully solve the problem of rock mass processing in underground conditions with subsequent operative disposal of final tailings of such underground dressing in the worked-out space. Besides, an integration of two processes into one is achieved, for example, a decrease in the rock mass coarseness with a simultaneous precise separation of valuable and waste components.

Aug 1, 2013

By J. B. Hamilton

The advantages of generating and distributing electrical energy direct from the coal-fields so closely affects the mining industry that a few remarks on the unbalanced phases of coal distribution is worthy of attention. The value of coal imported into Canada from 1912 to 1921 exceeded the sum of $580,000,000. In 1922 Ontario imported 1,640,000 tons of anthracite and 9,440,000 tons of bituminous coal. I submit that the use of Saskatchewan lignite in an electrical super-power plant equipped for the carbonizing of coal, and disposal of excess gases would be the commencement of a solution of the fuel shortage in Ontario. As Saskatchewan becomes more and more populated and manufacturing increases, the amount of by-product carbonized fuel available for shipment to Ontario will increase, and its shipment to that province would decrease the trade deficit of the national balance sheet. If and when this is carried out it will mean a better and wider market for Alberta fuels in Saskatchewan and Manitoba.

Jan 1, 1924

By Shahram Tafazoli

ABSTRACT: This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

Oct 1, 2009

By Shahram Tafazoli

This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

Oct 1, 2009

By Shahram Tafazoli

This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

Oct 1, 2009

The cost benefits of controlling dilution of extracted ore have been very well understood by miners and mining professionals for many years. However, as we strive towards more mechanization, the dilution factor has been compromised in order to fit ?equipment? that is better suited to provide improved safety and productivity. Alternately, the drilling and ground support is accomplished by handheld drilling. In 2007, a short study, commissioned by CAMIRO (Canadian Mining Industry Research Organization) on the safety of hand held drilling vs. mechanized drilling, concluded that the risk of injury with handheld drills was seven times greater than with mechanized drills. Armed with this data, MEDATech Engineering proposed to the CAMIRO group to fund development of a ?MICRO Bolter?.

May 1, 2009

By G. R. Sadowski

"Large subhorizontal joints have been found in the foundation excavations in basalt and granite of Brazilian Dams. Some spread for hundreds of square meters showed slickensides—polished surfaces plus striations—and laminations interpreted as related to shear displacement, what substantially reduced their shear strength and imposed special reinforcement measures against the potential sliding of overlying concrete structures. The geological characteristics of these discontinuities have raised speculations related to their origin, be it related to mechanisms of bulging, cambering or to some tectonic or primary geological event.Several geologists and engineers from the northern hemisphere including Terzaghi already showed to be concerned with their role in granite foundations while in the southern regions Brazilian authors have found similar occurrences but also affecting individual lava flows of continental flood basalts in the foundations of major dams of the Parana Basin, which they designated under the particular name of “fault-joints”. This double-standard designation is self-explanatory of the difficulties involving their origin and related geomechanical properties: faults or just shear joints?Recently, similar features were encountered in the foundations of large dam constructions in anorogenic granites inserted in the realm of the Brazilian Amazon, where some of these discontinuities exhibit features common to tectonic thrusting combined with deep tropical weathering.The evidence of preshearing along the surfaces of such fractures, also associated to products of deep weathering, reduces their geomechanical strength substantially, suggesting values of ultimate phi spanning 12 to 28°. The detection of these descontinuities during initial investigation phases continues to be a major complex task in geological risk evaluations surveys. Trenching associated to some geophysical exploration techniques, although considered to be very basic exploration techniques are still the suggested methods for their forecast and previous determination."

Jan 1, 2015

Waste rock extracted from a mine is typically stored nearby on the surface. Such waste rock piles must be designed to ensure their geotechnical and geochemical stability during the mine operation and after closure. The optimal construction of a pile requires detailed planning. Deposition should involve benches of limited height to control the global slope angle, based on the long term factor of safety. It can also be advantageous to compact the top of each bench and to give the surface an outward inclination to control water flow by limiting infiltration and favoring lateral diversion. When part of the waste rock contains reactive minerals, it is also deemed necessary to use selective placement with the non-reactive portion to prevent direct exposure to natural conditions. The construction must be well documented, and include data from the monitoring program. These and related aspects are presented and discussed in the paper.

Aug 1, 2013

By Mark B. Thorpe

Golden Star Resources started gold mining operations in Africa in 1999 after 15 years of exploration in South America. At the time, the approach to local assistance was through "alternative livelihood" programs and the donation of infrastructure to local communities. This was initially successful with local community support. However, with time and on reviewing the implemented projects, it became evident that the success was limited and many if the projects were either poorly used or in disrepair. Through a review of the options, we decided to develop a community assistance model driven by the communities themselves, while keeping control of the finances and the actual construction of the projects. Through the formation of the Golden Star Development Foundation, we began to support community driven projects for local economic development. The evolution of economic development projects continued over the next several years with the addition of project requirements for partnerships with government, and finally an evolution to a partnered turn-key piece of infrastructure that we hand over to an agency for operation and ongoing maintenance. We are currently working with outside partners to further our economic development activities in Ghana to the benefit of our stakeholders.

May 1, 2011

By C. Pichler, S. Luidold, C. Wagner, C. Sagadin, D. Kreuzer

Engineers and scientists have been combating the attack upon refractory materials of molten metals/matte and slags for hundreds of years. The details in many cases are still questionable or at least debatable. The corrosion is a major concern for furnace operators as refractory wear or failures inevitably results in reduced production efficiency and furnace reliability. Also the cost to industry is considerable and only a thorough understanding of all the complexities of the process will help to minimize that cost. One of the critical questions to overcome is the correct selection of refractories for the individual process steps to provide long and predictable refractory life together with high furnace availability. To understand the nature of the reactions involved in refractory corrosion, it is crucial to determine the complex thermo- chemical equilibria of the reactions occurring between the refractory materials and the process phases. A simulation model coupled with commercial software like FactSageTM is demonstrated aiming to understand the corrosion mechanisms between refractories and the molten process phases and draw implications for improving the performance of refractories and refractory lifetime. INTRODUCTION The extraction or recycling of valuable materials, e.g. metals, can be done by two main routes, pyro- and/or hydrometallurgical processing, depending on the chemical behavior of the used ore, scrap or pre-treated concentrate. Sometimes it is also necessary to use both process routes for the extraction or the recycling of valuable materials. In the case of a pyrometallurgical treatment, the usage of refractory materials is inevitable. This is mainly caused by high temperatures, prevailing during processing. The interaction between refractory material and slag, metal or matte leads to different reactions and interactions. As a main result corrosion of the furnace lining (refractory material) takes place. Hence, recurring furnace shutdowns occur for renewing the refractories. This leads to reduced production efficiency. Such refractory lifetimes are between some hours and decades, depending on the processes.

Jan 1, 2019

By François Charette

High stress conditions in underground mines push the performance envelope of support systems to their limit. In weak rock masses these conditions lead to large deformation and breakdown of the rock material, while stress release events in hard rock mines can lead to sudden and usually violent rock and support failure. In typical support systems, a combination of different reinforcement and support mechanisms provide the required convergence control and retainment. These systems usually involve a multi-pass support installation. The advantages of a single pass support system are investigated and several bolting combinations are compared. Criteria for design are reviewed and new criteria are proposed to include cost and effectiveness in commonly used engineering approaches. Field observation and testing is used to illustrate the difference between the proposed approach and more conventional systems.

Nov 1, 2011

Agenda ?Introduction ?Geology ?Mining ?Metallurgy ?Process, Layout ?Environmental Background ?Kinross Gold Corporation owns the Lobo-Marte gold property, located in Region III of northern Chile. ?The property is close to two other Kinross mines, Maricunga 50kmto the south and La Coipa 60km to the north, plus a regional office in Copiapo and district level operating synergies are expected. ?Lobo and Marte were discovered in the early 1980s and are intrusion-hosted, porphyry-type precious metal deposits, typical of the Maricunga District. ?The Marte open pit heap leach mine was in commercial production in late 1988, but was suspended in February 1992 as it did not meet forecasted production levels and recoveries. ?Kinross plans to recover ore from the Lobo and Marte deposits through an open-pit, heap leach47,000tonne per day operation.

May 1, 2010

By G. R. C. Pacheco, D. M. Fonseca, R. Neuböck, G. E. Gonçalves, W. Moulin-Silva

Degradation by sulfur gases is an important lining wear mechanism in the copper industry. SO2/SO3 gases infiltrate into the pores of the basic refractory bricks, combine with their raw materials through expansive reactions and significantly modify the bricks’ structure. This study presents a comparison of the corrosion resistance against sulfur attack of different magnesia-based refractories using a simple, low-cost and quantitative method. Recipes containing sintered MgO grains showed lower resistance to corrosion by sulfur oxides compared to basic grades containing fused grains. Chromium corundum grades were used as a reference and showed very good resistance to this corrosion mechanism under the test conditions. The novel test provided relevant results that agree with what is commonly observed during operation and in previous post-mortem studies. This tool could be very useful in selecting refractory grades for the copper industry and predicting their performance. INTRODUCTION Oxidation of matte sulfides during copper production leads to the formation of sulfur oxides, which infiltrate into the pores of the refractory lining and react with the basic oxides below 1000°C to form magnesium and calcium sulfates. This reaction is accompanied by an expressive volume increase, consequent densification of the refractory microstructure and weakening of the brick bond (Malfliet et al., 2013). Thus, corrosion by SO2/SO3 is an important wear mechanism in the non-ferrous industry and the resistance to this compound should be considered when defining refractories for this application. Previous studies on this matter include expensive and complex testing methods involving pressurized SO2 gas cylinders in order to investigate the corrosion resistance of MgO-containing materials by sulfur oxides (Gerle & Podwórny et al., 2016; Fotoyi & Eric, 2011; Fotoyi, 2009; Podwórny & Piotrowski et al., 2008). The current study was based on a test developed by Pacheco & Fonseca (2018) to assess alkali infiltration and aims to provide an evaluation method of the corrosion resistance of refractories by SO2/SO3 in a simple and quantitative manner. This novel test is useful to compare the corrosion resistance of different refractory recipes and properly select the grades that should be employed in the non-ferrous industry. A case study is provided to illustrate the damage caused by sulfur oxides in refractory linings.

Jan 1, 2019

By T. P. Lim, N. K. Davé

"A modified accumulator method was devised to measure surface radon flux from porous media. It consists of a collector hood type of accumulator with a homogenizer pump and a pressure balancer. The latter was used to compensate any pressure changes produced during sample withdrawal and hence eliminate additional radon transport from the media. Errors resulting from radon back diffusion due to decreasing concentration gradient with time across the interface were also eliminated by measuring radon concentrations in the accumulator for two different periods of time and calculating the true radon flux, J(o), from the solution of a time-dependent radon transport equation in the absence of any pressure and temperature gradients.Core samples from the observation site were also withdrawn for laboratory determination of porosity, moisture content, bulk and grain densities, Ra-226 source concentration and the fraction of Rn-222 produced in the void volume. The data were used to calculate the radon diffusion coefficient for the media.Using the present method, the true value of surface radon flux for an abandoned uranium tailings pile was obtained as J(o) = 2020.2 mBq/m2/sec (54.6 pCi/m2/sec) compared to the value J = 1406.0 mBq/m2/sec (38.0 pCi/m2/sec) obtained by the conventional method. The bulk diffusion coefficient of radon for the media was obtained as 1.2 x 10-7 m2/sec.IntroductionRadon-222 (hereafter called radon) released from uranium mill tailings is a continuous source of environment radioactivity in terms of its transport as an airborne gas and its decay products. The particulate daughter products readily attach to aerosols or dust particles and can further be transported by various other environmental pathways. Typical radon release rates from existing tailings piles vary between 740 and 14,800 mBq/m2/sec (20-400 pCilm2/sec), depending on the nature of the tailings material, moisture content, etc. The United States Nuclear Regulatory Commission (NRC) is proposing radon release rates of 74 mBq/m2/sec (2 pCi/m2/sec) above that of background."

Jan 1, 1982