Search Documents

By Andreea Catalina Gluhoi

Oxidation and reduction reactions of N-containing molecules have been studied over different types of gold-based catalysts, Au/MOx/Al2O3 and Au/MIOx/MIIOx/Al2O3 (M, MI, MII=Li, Rb, Mg, Ce, Zr, Mn, Cu) prepared by deposition precipitation with urea. In general, all the catalysts were already active at low temperatures. NH3 oxidation was effectively catalyzed by Au/CuO/Al2O3, a catalyst which also gives the highest yield in N2. NO reduction by H2 performed over gold-based catalysts produced N2O, N2 and NH3 and N2O reduction resulted in the formation of dinitrogen. For all the reactions, large synergistic effects have been obtained by addition of different kind of additives.

Oct 1, 2003

By Davis Myers

OVERVIEW ?A summary of population demographics data ?Potential impact of Baby-Boomer, Generation X, Millennial demographics in the mining workforce ?Planning with constrained resources Age Cohorts ?Baby Boomers: born 1946 -1965 ?Booming economy, TV, cold war, JFK, Vietnam ?Generation X: born 1965-1980 ?There was always space travel ?PC?s, Black Monday, Challenger, Desert Storm, fall of Berlin Wall ?Millennials: born 1980-2000 ?There was always the internet ?IM, Facebook, Sept 11, Columbine

Nov 1, 2011

By Lindsay A. Robertson

The long term management of acid generating tailings at mine closure is a common issue, however, management of ARD is significantly impacted by local conditions, including climate. Acid generating tailings, over time, will produce acid rock drainage (ARD) if left exposed to water and air, which both contribute to the sulphide oxidation process. The long term closure of tailings storage areas is a concern from both environmental and engineering perspectives, with long term acid generation and dam stability the main risks. Several approaches can be taken to minimize ARD from tailings facilities using cover systems. Three tailings facility cover case histories, in areas of net positive water balances, were investigated using unsaturated flow modelling software to determine the long term potential for limiting ARD by increasing saturation of the tailings and decreasing oxygen ingress. Each case study demonstrates the importance of integrating the tailings dam engineering into tailings cover closure design. Model predictions are compared to measured saturation levels to assess the accuracy of the calculations.

May 1, 2011

By E. C. De Matos

The Uranium Province of Lagoa Real is located in the mid-south region of Bahia State, Brazil. Uranium is the only mineral wealth, occurring mainly in the form of uraninite. The region has been searched for uranium since 1971 and 35 anomalies were detected, distributed over 1200 km2. Seven are now taken as deposits, accounting for reasonably assured resources of 100.000 tons of U3O8. This paper describes the geological aspects of the area, the exploration and mining activities done so far by the state company INB and the perspectives for the near future, when a raise in the country?s uranium demand is expected.

Aug 1, 2010

By Barbara Kirby

Mining Industry HR Challenges Mining industry needs to hire approx. 100,000 workers by 2020 Attraction and retention of talent in all occupations Mobility of skilled workers between mine sites 70 percent of employers expect labour shortages over the next 5 years. Largest shortages: -physical sciences and engineering occupations -trades and ?undesignated? occupations ?Undesignated? Occupations ?Undesignated? Occupations -eg. mill operators, production / development miners and heavy equipment operators More than 20,000 workers will be needed by 2020 in the undesignated occupations and another 11,500 tradespersons Turnover rate for trades and undesignated occupations at mines is high: 8.3% compared to 5.6 % for all other occupations There is no system to recognize the skills of high-demand undesignated occupations

May 1, 2010

By T. Macpherson

ABSTRACT: Drawing on past research experience with sprayable polymer mine support agents (TSLs), Spray On Plastics Ltd. has developed a TSL ground support system called RockWeb. Using a relatively new polyurea polymer technology, RockWeb has been engineered to solve problems encountered underground with polyurethane liners by incorporating rapid curing, moisture insensitivity and superior physical performance. RockWeb possesses a unique, patented ability to be sprayed in a ?cobweb? like consistency allowing the applicator to span fissures in the rock, ensuring no initial defects in the liner, and maintaining design thickness over highly irregular surfaces. This ability, coupled with the high strength and elasticity of polyurea, allows RockWeb to mitigate rock movement through yielding, while maintaining intimate surface confinement. RockWeb provides reduction in logistics through the transport of 1/25 of the material quantities required for shotcrete, rapid deployment rates of as little as 30 minutes per round, and immediate return to the work area. This paper will discuss the technology and advantages of RockWeb as well as opportunities for overall mining cycle cost reduction. The safety benefits, as well as health and environmental considerations regarding application of isocyanate-based liners will also be discussed.

May 1, 2009

IBI Alliances ? Government ? People ? Academic ? Associations ? Media ? Customers ? Agencies ? Shareholders ? Industry consultants ? Investment Authority ? Geological Survey ? Department of Mines ? People ? Local Residents ? Mineworkers ? Academic ? University of Guelph ? Uganda Vermiculite Institute ? Associations ? TVA ? Organic Certification ? Media ? Canada ? International ? Customers ? Advocacy role ? Agencies ? Regional International

May 1, 2006

By Jan Nemcik

Among other products steel mesh has been used successfully for many years to support strata and minimise loose material from falling into the mine opening. Installation of steel mesh has proven to be difficult to automate and many other products, such as Thin Spray-on Liners (TSL), have been proposed as a replacement. Ideally, the mechanical properties of these products should be superior to those of the steel mesh, however, most TSL trialled in mines to date have been weak and in addition have had slow cure times, as a result none of these materials can seriously compete with steel mesh. Now a new polymer product that cures in seconds and forms a stiff strata binder that surpasses the properties of steel mesh is under development at the University of Wollongong. To enable selection of a suitable polymer material for roadway skin reinforcement several numerical models were constructed to investigate the role of interface roughness and the influence of polymer stiffness on load transfer along the rock-polymer interface. Laboratory tests indicate that the shear adhesion of the rock-polymer interface can be substantial while the tensile adhesion can be much lower. The models indicate that the natural stone roughness and surface waviness plays a major role in shear adhesion while the elastic properties of polymer liner can significantly influence the polymer ability to resist fracture opening.

Oct 1, 2009

By F. Rosenblum, P. Spira

A laboratory test has been developed for assessing the patential hazard from self-heating of sulphides. The technique consists in measuring the rate of self-heating, from near ambient temperature, of a 1-kg sample in an insulated chamber controlled at standard atmospheric conditions. The rate of oxygen consumption is monitored simultaneously. The paper describes the apparatus and test procedure, and reports data on various ores and mill products. Tailings known to have caused problems underground when used as backfill have shown heating rates of over 3°C/h. A preliminary hazard rating guide for backfill based on the known behaviour of several sulphide materials is presented.

Jan 1, 1981

By G. E. Agar, R. Stratton-Crawley

"The applicability of a hydrocyclone model to simulation of the cyclone banks in a multi-stage sandplant circuit producing mine back fill has been demonstrated. The model ha~; been used in conjunction with a modular computer program for circuit simulation in order to study the effect of changes in the operating conditions. It has been shown that weight recovery to sand fill increases as feed percent solids decreases, and, to a lesser extent as pressure drop across the banks increases. An increase in apex diameter also causes an increase in weight recovery. Increased weight recovery must, however, be balanced against sump an1l cyclone capacity and dilution of sand fill by fines. The predicted results from circuit simulation were in good agreement with plant data.The model has been found to be applicable to widely different ores."

Jan 1, 1979

By L. A. Gomieroa

The Caetité-Brazil uranium facilities produce about 340 t/y of uranium from an ore averaging 0,25 U %. The process steps are ore crushing, heap leaching with sulfuric acid, U separation and purification by solvent extraction with tertiary amine followed by stripping with sodium chloride solution and precipitation as ammonium diuranate that is dryed. A change in the milling process is being evaluated to increase the production and the uranium recovery. Heap leaching will be changed to conventional tank agitated leaching of the ?590 ground ore slurry in sulfuric acid medium. The replacement of the stripping reagent is also being considered.

Aug 1, 2010

By Patrick Chabot

Ce document présente une méthode hybride de long trou favorisant une méthode de minage initiale par chambre-magasin et complétée par une méthode de minage long trou. Cette méthode a été adaptée suite à plusieurs facteurs tels qu?une géologie complexe, une rareté de mineur d?expérience et un haut taux de roulement de main d?oeuvre spécialisée. Cette méthode a permis d'excellents résultats par rapport à la dilution. De plus, la récupération de pilier à haute teneur par forage long trou sera expliquée. Cette méthode permet aussi de récupérer le minerai qui est resté accroché dans les chantiers chambre-magasins. Introduction : La mine Géant Dormant est une mine filonienne d?or située à environ 80km au nord de la ville d?Amos au Québec. Elle est en opération depuis 1988 et à la fin de 2007, elle a produit près de 885 000 onces d?or à partir d?environ 2 400 000 tonnes de minerai pour une teneur moyenne d?environ 11,5g /t Au. Cette mine est la propriété d?IAMGOLD Corporation depuis l?acquisition de Cambior par cette dernière au mois de novembre 2006. Elle emploie 151 employés permanents et environ 41 entrepreneurs.

Feb 1, 2008

By Cheryl L. Allen

Increasing energy costs associated with mining have become an issue that must be addressed by industry to ensure sustainable production. As underground mine ventilation systems account for 40% to 50% of a mine?s total energy requirement, initiatives to maximize their efficiency have been introduced worldwide. A control method known as Ventilation-On-Demand (VOD), which adjusts the ventilation system by responding to the activities of mine personnel and air quality, has been commissioned at Vale?s Coleman Mine. This initiative is an effort to reduce energy consumption, maximize efficiency of the ventilation system while ensuring air quality. There are five control strategies that can be executed with the VOD control system in place at Coleman Mine: Manual real time control Time-of-Day Scheduling Event-based control Environmental control Activity Based Control/Tagging This paper describes the system, control strategies and impact on energy consumption and flexibility of airflow distribution as applied at Vale?s Coleman Mine.

May 1, 2011

By Juliana Parreira

The past decade shows record increases in global demand for minerals and metals with an accompanying significant decline in skilled personnel. Mining companies today are examining new technologies to maximize production, reduce costs, and create safer work conditions to deal with this shortfall. Automation of an open-pit mine haulage system is receiving attention as a beneficial option since it provides more consistent and efficient operation of mining equipment, it removes workers from potential danger, it reduces fuel consumption significantly reducing greenhouse gas (GHG) emissions, and it can help optimize vehicle repairs and equipment replacement because of more-predictable and better-controlled maintenance. This paper describes a simulation model under development using the EXTENDSIM software package to examine scale-up issues and constraints of autonomous vehicles in comparison to a manual system. The software can predict and manage Key Performance Indicators (KPIs), such as productivity, safety, cost, equipment failures, fuel consumption, and tire wear under different road and load conditions. By breaking-down the various systems of an autonomous haulage truck and simulating the overall haulage system using a Monte Carlo approach, the model becomes a flexible and powerful tool to use within a mining organization. Direct comparison to a manuallyrun system can be done to show the cost and operational benefits of automation. Project managers can use this tool to guide decision-making about possible application of autonomous haulage trucks at a specific mine site.

May 1, 2010

By Jean-Guy L. Gauthier

"With the Ontario Ministry of the Environment stipulating that the cumulative concentration of copper, lead, zinc and nickel in mine mill effluent must be no greater than 1.0 milligram per litre, it has become necessary for the mining industry of find some form of treatment for the removal of heavy metals from effluent waters.To comply with these guidelines, it became necessary for Mattabi Mines Ltd., which is situated 50 miles Northeast of Ignace in Northwestern Ontario, to develop a compact, cost effective and technically sound treatment process to remove heavy metals from their tailings overflow. A design committee consisting of mine metallurgists, environmental engineers, a Dutch research and development team and the equipment supplier engineering staff was set up to accomplish this.Using some new and innovative wastewater treatment equipment, the guidelines established by the Ontario Ministry of the Environment can now be met. The sludge produced from the precipitated heavy metals is sent directly to the concentrator, thus eliminating the danger of re-dissolution of the metals in a landfill site, while recovering some of the valuable metals that would otherwise be wasted in a sludge landfill."

Jan 1, 1980

By Pierre Laliberté

Introduction ??Mine ventilation is a major consumer of power in underground mining, including air heating (winter) and air conditioning (deep mines). ??Any advances, including the development of low emission vehicles, that can improve underground air quality can reduce ventilation demand, and likewise reduce costs and energy consumption, including their associated greenhouse gas emissions.

Nov 1, 2011

By P. R. A. Andrews

"Garnet occurs in schists and gneisses in all provinces of Canada, all mainly in Quebec and Ontario. There is currently a renewed interest in exploration for economic sources of garnet for abrasive applications because of the inherent dangers from exposure to ground silica from sandblasting operations.High-quality garnet is used for lapping and grinding of glass and ceramics; for coated and bonded products such as sandpaper and cloth; and abrasive wheels for grinding and finishing various metals, woods, rubber and plastics. Low-quality garnet is used for cleaning and conditioning aluminum and other soft mewls, particularly by aircraft manufactures. Garnet may be added to grouting cements for oil-well drilling applications, and it has also been used for low- to medium-level radiation shielding. Garnet has been studied extensively by CANMET and its predecessor, Mines Branch, between 1917 and 1990. Twenty-nine studies relating 10 various aspects of beneficiation are presented and a review of the more important studies is presented. The information includes mineralogy, beneficiation methods, product sizes and analyses."

Jan 1, 1995

By Patrick Andrieux

Cet article décrit une nouvelle méthodologie qui quantifie les chances de succès d’un sautage confiné à grande échelle de relaxation des contraintes dans un pilier de mine souterraine, pour un massif rocheux et un régime de contraintes donnés. La méthode est basée sur un nouveau paramètre nommé « Indice de relâchement », qui considère huit paramètres géomécaniques et de forage-sautage qui contrôlent ultimement le procédé. La rétro-analyse d’études de cas bien documentées a démontré que l’approche peut indiquer de manière fiable si une situation donnée de hautes contraintes de terrain est susceptible d’être améliorée par un tir de relâchement confiné à grande échelle et si le design proposé est adéquat pour atteindre ce but.

Jan 1, 2009

By A. J. Sinclair

Abstract-Exploratory data evaluation is an essential part of every high quality, mineral inventory estimate. Efficient analysis involves a thorough organization of available quantitative data that are the basis of the estimate and perhaps the formation of composite grades. Data organization and evaluation can involve more than 50% of the time necessary to conduct a mineral inventory estimation. The principal purpose of exploratory data evaluation in mineral inventory work is to improve the quality of estimation by providing insight into characteristics of the variables under investigation. Specific aims include: (1) to recognize and eliminate errors; (2) to provide a comprehensive knowledge of the statistical characteristics of all variables of interest for resource/reserve estimation; (3) to document and understand the interrelationships among the variables of interest; (4) to recognize systematic spatial variation of variables such as grade and thickness of mineralized zones; (5) to recognize and define distinctive geological domains that require independent estimation of mineral inventory; (6) to identify and characterize outliers; and (7) to evaluate similarity/dissimilarity of various types of raw data, especially samples of different supports. These aims are not mutually exclusive but they can all have their own impact on resource/reserve estimation. Error must be minimized. Individual variables can have characteristics that lead to different decisions in the course of estimation. Similarly, interrelations of variables might contribute to the ease (or difficulty) with which estimates of several variables can be obtained. Trends can impose the need for two or more domains, each of which might be estimated independent of the others. Outliers, a perennial problem, require detailed evaluations because they impact on reserves much out of proportion to their abundance. Data, of widely different supports, generally must be standardized if all are to be used for purposes of estimation.

Jan 1, 1998

By R. S. Adhikari

It is necessary to assess the physical and functional conditions of highway bridges at regular intervals to ensure they still meet their service requirements. Currently, this condition assessment is mainly performed through visual inspection, which has been identified with several limitations (e.g. the timeconsuming assessment process and heavy reliance on inspectors? personal experience). In order to overcome these limitations and enhance the current inspection practice, this paper presents a novel method for automated bridge condition assessment using a hybrid sensing system. Under the method, existing conditions of bridge components are first captured with a stream of point clouds and color images. Then, the bridge components and the defects inflicted on the components are detected utilizing their visual patterns. The detection results are mapped to the point cloud. This way, the 3D information of the components and defects can be retrieved. The bridge condition assessment can be made effectively through the 3D visualization of this information before carrying out any on-site detailed evaluations.

Aug 1, 2013