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By F. Wirfiyata

"Accurately modeling and predicting long term mill throughput is one of the challenges facing metallurgists, geologists and mine engineers in their quest to consistently deliver accurate life of mine business plans.Batu Hijau has systematically improved long and short term mill throughput predictions since feasibility and commissioning in 1999. This has been achieved through a combination of ongoing improvement to the geology ore hardness and grade characterisation model, drill and blast optimisation and, by application of these data to model mill throughput.Batu Hijau has demonstrated the ability to consistently estimate long term mill throughput within ±2% accuracy. Aside from reliably predicting expected production rates with the existing plant configuration, this predictive ability provides a solid foundation for identifying operating and design criteria for short term grinding circuit optimisation and future expansions.This paper discusses ongoing throughput prediction model development at Batu Hijau based on geo-metallurgical characterisation. Also discussed are tools used for day to day production performance management. This includes on line ""Mine to Mill"" variable monitoring to improve operations parameter decision making and performance assessment."

Jan 1, 2012

By A. Farzanegan, D. A. Lowther, A. R. Laplante

"Off-line optimization studies are often necessary to improve the efficiency of grinding circuits. These studies are primarily based on the mathematical modelling of processing units (e.g., ball mills and hydrocyclones) and computer simulations. To complete an optimization task, process engineers must possess skills and knowledge of different subtasks involved in such efforts, e.g., plant audit, laboratory tests, and data analysis. Such know-how can be in part provided by Knowledge-Based Systems (KBSs). One such system, being developed in C Language Integrated Production System (CLIPS), is presented here, with focus on the estimation of ball mill selection functions for the purpose of both diagnostic and simulation, and its use for the optimization of ball size. Some of the interpretation and diagnostic rules will be presented, as well as grinding kinetics and classification data likely to fire them.IntroductionSince the late eighties there has been a growing trend in applying Knowledge-Based Systems (KBSs) to mineral processing [Meech 1990, Bearman and Milne 1992). Table l lists some KBS (often referred to as expert systems) applications that have been used mainly as tools for improving on-line monitoring and control of grinding circuits. However, there has been fewer attempts to add the symbolic processing powers of KBSs to conventional off-line grinding simulators. Figure 1 shows a relatively standard procedure to perform an off-line optimization study [Napier-Munn and Lynch 1992]. In brief, a typical program includes taking representative samples from a number of streams, running laboratory tests on collected samples, estimating model parameters which describe physical processing units (e.g. ball mills and hydrocyclones) validating model predictions and using models for simulation trials. One inevitably needs to be familiar with concepts of process modelling and simulation as well as various computer programs to be able to complete all steps of the study. Much of this ""expertise"" can be captured by KBSs, given their inherent capabilities for symbolic knowledge representation and manipulation."

Jan 1, 1997

By Min-Yuan Cheng

Landslides not only cause interruption of road traffic but also cause damage to passing by vehicles and injure people in Taiwan. Due to the budget limitation of government, the overall assessments and maintenance of all road slops cannot be fulfilled. Priority of road for maintenance is a crucial task for road maintenance department to identify. The purposes of this research are to develop an assessment method for the landslide risk and to make strategies to maintain or repair the slopes along mountain roads. To aim both needs to take into account the environmental conditions of the slopes, the engineering measures for stabilizing road slopes, the transportation issues, and the human concerns when dealing with the slopes maintenance along the mountain roads. This study firstly establishes the Landslides Damage Risk Evaluation Model (LDREM) to calculate the risk of slope failure, considering the probability of landslides, temporal probability, spatial impact probability, the value of human life, transportation time increased, and travel cost due to detour etc., and then the loss of life and transportation can be calculated. Secondly, based on the value of risk and the risk evaluation, considering the risk acceptance criteria for loss of life could provide assistance for road maintenance department to determine the priority of mountain roads for maintenance.

Aug 1, 2013

By S. A. Kenzap

This paper provides an overview and discussion of key aspects of operating risk valuation in underground metal mining systems, with impact on project economics, using stochastic computer modelling in Discounted Cash Flow (DCF) analysis. Mine operating risk classification and assessment for ground, equipment and scheduling aspects are presented with an overview of available risk valuation tools that have been developed in engineering disciplines. The classification is organized by keeping in perspective the mine design needs and constraints, as well as the potential economic impact that operating problems can have on an underground development and production system. These sources of cost, revenue and time delays are tabulated to enable the hierarchization of potentially hazardous unplanned events occurring during the mining project life cycle. In complex technological systems, like the underground mining systems, the decision-making process involve a wide range of uncertainties, and often this is based on subjective and qualitative expert evaluations. Whether a qualitative or quantitative analysis is conducted, it is often the case that the probability of a certain project parameter value needs to be estimated. This requires use of methods and techniques to handle subjective, qualitative measures and to combine them with quantitative stochastic modelling in order to evaluate mine operations-related issues on DCF economic performance measure parameters. Links are established between decision making and the risk-based mine planning process for evaluation of design alternatives, with emphasis on the need of introducing flexibility in mine design. Finally, challenges of risk-based mine planning and design implementations are discussed and the call for an integrated risk-based real options systems valuation (ROV) ?in? projects analysis is made.

Aug 1, 2013

By Eugene Sun, Qiang Xu

This presentation will review current applications of composite materials in aircraft design and discuss the challenges involved in maximizing the potential of the composites in aircraft applications.

Jan 1, 2010

By A. J. Basu

Air quality in underground mining operations can fluctuate significantly during the working day, but until recently the only way to ensure a mine had sufficient air quality was to over-ventilate and, with significant delay in adjusting the volume or direction of the airflow, working conditions were tolerable but rarely ideal. Underground ventilation management systems have been considered to achieve improved energy efficiency since at least 1995 in Canada. However, Mine Ventilation Optimization, (MVO) and integrating it with Ventilation on Demand (VOD) is only becoming more of a reality in the last seven (7) years. A systems approach to MVO takes into account all the elements from the point the power is distributed into the ventilation fans through to the actual quality and quantity of fresh air to the working face. Opportunities exist throughout the system for energy savings but not all of them are cost-effective. Depending on the application, these opportunities can be easily realized by properly sizing, streamlining, maintaining and operating the ventilation system using premium mine proven energy efficient components throughout. Implementation of VOD is a key step in achieving the MVO objective. However, VOD is a concept, and it requires various tools, procedures, and strategies for cost-effective and operationally viable implementations. This paper provides a historical background in the development of VOD and provides a framework for proper and cost effective implementation. In addition, an optimized ventilation system will also allow increased airflow by reducing resistances and shock losses. This turn in would allow production target improvement, which could be an attractive objective compared to energy savings. Mine ventilation is the life support system of an underground mine, and contributes to sustainable development and corporate social responsibility goals assuring health and safety aspects of strategic planning. The proposed framework addresses implementing mine ventilation optimization integrating ventilation on demand as a vehicle for energy, health and safety improvement and overall productivity gains in the mining cycle efficiency while significantly reducing carbon footprint of a mine.

Aug 1, 2013

By H. Asgari, A. G. Odeshi, J. A. Szpunar

In the present study, the dynamic response of AZ and AE cast magnesium alloys to shock loading, are compared for strain rates ranging between 900 and 1200 s-1. Texture measurements showed that after shock loading, the (00.2) basal texture component of both alloys was strengthened. However, the strengthening magnitude was higher for AE samples. Also, it was observed that the twinning fraction decreased in both alloys with increase in the amount of alloying elements. In addition, cracks are formed at the interface between matrix and second phase particles in the AZ alloys. However, crack nucleation and fracture in AE alloys occurred at the sites where twins accumulated. Furthermore, analysis of the dynamic mechanical behaviors showed that the ductility of AE grade is higher than that of AZ alloy for all strain rates used in this research. This difference was explained by differences in deformation mechanisms of these alloys.

Jan 1, 2014

By Dani J. Alldrick, Alastair J. Sinclair, Colin I. Godwin

"The Stewart mining camp has a long history of precious and base metal mining. The camp is abundantly mineralized, with more than 200 widespread, varied, vein prospects, deposits and orebodies. These show wide variations in the mineralogy of ore, gangue and alteration assemblages, and wide variations in textures and structural settings. This report establishes the timing of the different metallogenic epochs and suggests a specific exploration application for systematic leadisotope analyses.Galena lead isotope ratios from a range of mineral occurrences indicate that all these varied deposits formed during two main mineralizing events. Lead isotope data from the Stewart mining camp do not provide absolute ages for the formation of mineral deposits, but the relative distributions of data are consistent with dates determined in other studies. One ore-forming episode occurred in the Early Jurassic and the other in the Middle Eocene. Both metallogenic epochs were brief, regional-scale phenomena. Some deposits from the younger mineralizing episode were emplacedadjacent to or superimposed on the older deposits.Field and laboratory studies show that the two metallogenic epochs are characterized by different base and precious metal suites: Early Jurassic gold-silver-zinc-lead-copper; and Middle Eocene silver-lead-zinc. Therefore, showings of different ages have different base and precious metal potentials and deserve different exploration emphasis. Lead isotope studies provide a reliable, cost-effective method for evaluating the age and commodity potential of small or recently discovered mineral showings and for setting exploration priorities on properties with several varied mineral occurrences. The determination of the age and metal potential of a prospect at an early stage of exploration may govern the urgency, intensity or even the necessity for further exploration work."

Jan 1, 1993

By R. Binning

"Economic high density mineral reclamation and subsequent transportation of solids through a pipeline presents many formidable engineering problems.Mineral reclamation system design by theoretical formulas is almost impossible because solids composition, ie. concentration, velocity, moisture content, solid size, etc. can only be controlled within a broad pumping range.Traditionally this has restricted pumping to relatively dilute slurries whereas it is usually preferred, because of economic considerations to reclaim as high a concentration as possible.At Toyo/De-Velde Corp. we recognized these pumping limitations and began to develop and manufacture a range of standard and auxiliary equipment that would exceed these technical restrictions.MATERIAL RECLAMATION & PIPELINE INJECTIONTo minimize fluid usage and increase material reclamation efficiency we designed a submersible dredge mixing pump that uses most of its energy to pick up material from rest, mix it with fluid into a highly concentrated slurry then push it firmly into a pipeline.Where material is too compacted to be mined by the standard submersible mixer pump, auxiliary high torque self contained submersible excavators can be fitted around the periphery of the mixer pump. This is to facilitate excavation and break up of the compacted material into a slurry.High flexibility of this system can be achieved by combining the many equipment variations available into the most efficient format to fit individual site requirements.Whatever combination of equipment is selected, torque is nullified by counter rotating excavators against each other. This increases effective excavator/material bite torque but also allows mixer/excavator rig suspension by cable for deep water material recovery."

Jan 1, 1985

By T. Takahashi, K. Oyamada, Y. Miyata, T. Isoo

The carbonation reaction of steelmaking slag has been known for many years. However, the size of blocks manufactured from this by-product material has been limited due to the difficulty of achieving a uniform reaction throughout the block. Using newly developed conditions, large porous slag blocks (1.0 x 1.0 x 0.5 m) were produced by car¬bonation of steelmaking slag with the optimum amount of water and supplying CO2 deep into slag powder compacted in molds. The development of these blocks has great poten-tial to solve the problem of slag utilization, for example, by recycling slag in large car¬bonated blocks for artificial fish reefs and seaweed cultivation beds. This paper de¬scribes the carbonation reaction, the new process for producing large slag blocks, and the utilization of blocks in past and recent years.

Jan 1, 2004

By Michael T. G. Brown

Syncrude Canada Ltd. has recently completed construction of its ambitious tar-sand mining and processing facilities at Mildred Lake, Alberta. The Syncrude site is approximately 48 km (30 miles) north of Fort McMurray near the west shore of the Athabasca River. The Syncrude operation involves the open-pit mining of approximately 270,000 tonnes (300,000 tons) of tar sand daily using draglines and a conveyor system. Bitumen is extracted from the tar sand, upgraded to oil-gas and transported to refineries in Edmonton and other locations for final processing . The Beaver Creek Dam forms part of the mining facilities for the Syncrude tar-sand mining operation. Water from Beaver Creek is diverted from the open-pit mine site south to the Athabasca River via Ruth Lake and the Poplar Creek Dam. General site layout is shown on Figure I . Design of the dam was completed by R. M. Hardy and Associates Ltd. of Edmonton, Alberta (now Hardy Associates (1978) Ltd) . Construction was undertaken during the summers of 1974 and 1975 under the direction of Canadian Bechtel Limited, managing contractors for Syncrude Canada Ltd. Total length of the dam is approximately 2.8 km (1.7 miles), with a maximum height in the order of 16 m (50 ft) The Beaver Creek Dam is located in a broad, flat, poorly drained valley. About 50 per cent of the site is covered with treeless peat deposits, which ranged in thickness from in excess of 5 m (15 ft) at the east end of the dam to less than 1 m (3 ft) at the central portion. The peat deposits overlie Pleistocene meltwater sediments on top of clay/clay shales of the Clearwater Formation and the tar sands of the McMurray Formation. The peat deposits and high groundwater levels at the site combine to make the excavation and construction of a conventional rolled clay cutoff impractical. For these reasons, the slurry cutoff trench technique was utilized to produce an efficient and effective seepage cutoff under various sections of the Beaver Creek Dam .

Jan 1, 1979

By S. Brophy

Controlled Short Circuit ? Metal Inert Gas (CSC-MIG) welding is a process that can be referred as a "Cold Welding" technology. The CSC process is based on accurate control of the welding wire position, thus the mandatory requirement for the automation of the process. One of the main advantages of the CSC-MIG process is the rapid solidification of the deposited material, resulting in weldments displaying low porosity contents, and enabling the joining of thin sheet materials. These characteristics render this process an ideal one for freeforming of components, where rapid solidification would be efficacious. This presentation will focus on the progress made towards the freeforming of Al-based components in the NAIN laboratory at McGill University. The relationship between the filler metal used, freeforming (deposition) parameters, resulting microstructure and mechanical properties will be presented.

Jan 1, 2011

By Marty Hudyma

Mining-induced seismicity and rockbursting is one of the primary risks in deep mines. Seismic data management software has been created to facilitate analysis of mining-induced seismicity. The Mine Seismicity Risk Analysis Program (MS-RAP) is a purpose built database with mine seismicity analysis tools. One of the primary features of MS-RAP is the creation of seismic hazard maps in quasi-real time. The seismic hazard maps identify areas that are more prone to large seismic events and rockbursts, allowing risk management measures to be focused on the areas of greatest risk. These maps allow mining engineers to be more proactive about identifying and managing seismic related geomechanics risks in mines.

Oct 1, 2009

By T. P. Kostek

"Historically, gear pumps and motors have been popular in the mining industry because of their competitive cost, simple yet rugged construction, ease of rebuild, and relative long life and insensitivity to contamination. However, with the ever increasing ""popularity"" of fire-resistant hydraulic fluids, both users and manufacturers of gear equipment must make special considerations to enable the equipment to continue giving satisfactory performance even with the water-containing fluids.The paper discusses 60-40 invert emulsions and waterglycolsIntroductionMuch information has been published on the specific characteristics of the various types of fire-resistant hydraulic fluids. Fluid manufacturers' literature and other publications have dealt with such specifics as fire resistivity, seal compatibility and wear rate characteristics. Gear pumps and motors have been, and will continue to be, applied successfully in hydraulic systems employing both the ""invert"" emulsions (60-40) and water-glycols as the hydraulic fluid.Because most external spur gear equipment has been designed to function with petroleum oil as the fluid medium, certain guidelines must be followed to ensure satisfactory service life. FluidsThere are a number of different types of fluids which fall in the category of"" fire-resistant"" , the most common'being phosphate esters, water-in-oil emulsions, oil-in-water emulsions and water-glycols. The two in most prevalent use today as hydraulic fluids are the water-in-oil emulsions and the water glycols"

Jan 1, 1980

By M. R. Shadnam

This contribution provides an assessment of research and development efforts to optimize SOx, NOx and mercury capture in flue gas. Coa, characteristics and combustion conditions in a power plant have an impact on the types and concentration of flue gas pollutants. These factors can also affect the amount of pollutant removed. This contribution would also provide a comparative study of the technologies that holistically aim remova, of SOx, NOx and mercury altogether in coal-fired power plants. A portion of this contribution provides background information on regulatory drivers.

Jan 1, 2010

By E. Kordzadeh, M. Reza Bateni, M. Karaminezhaad, A. Moeini

A series of austenitic heat resistant Fe-Ni-Cr-Al alloys with different nickel contents have been investigated at 1100 ° C and 25, 50, 50,100 hours in S/0 bearing atmospheres. Before sulphidation test, the specimens were annealed in argon at 1250 °C for 8 hrs. Weight changes were measured using an automatic thermo gravimetric analyzer and corrosion products were analyzed by scanning electro microscope (SEM), energy dispersive X-ray spectrometry (EDAX), X-ray diffraction and optical microscope. The results showed that sulphidation resistance decreased with increasing nickel content. Internal sulphidation controlled by gaseous transport through cracks and pores and the formation of internal sulphide increased when liquid sulphides formed on the surface.

Jan 1, 2004

Mining Association of Canada ! Represent base and precious metal, diamond and oil sands producers as well as nonferrous metal smelting and refining ! Member companies account for the vast majority of Canada?s mineral and metal production ! Mining is a major economic sector in Canada ! 13% of total exports ($47 billion) ! Employment near 400,000 ! 4% of GDP The Kyoto Protocol ! November 18, 2004 -- Russia deposited its instrument of ratification with the United Nations ! The Kyoto Protocol entered into force on February 16, 2005 ! The Kyoto Protocol is now an international and legally binding agreement to reduce GHG emissions world wide ! Canadian GHG target = 6 percent below 1990 ! First Commitment period 2008-2012

Apr 1, 2005

By D. G. Dixon

A novel technology for leaching copper from primary copper concentrates has been developed at UBC. This patented technology takes advantage of the galvanic couple between pyrite and chalcopyrite to ensure rapid and complete oxidation of chalcopyrite under mild conditions in acidic iron sulfate solution, without the need for microbes, ultrafine grinding, or chemical additives such as chloride, nitrate, or surfactants. Copper recoveries of 98% or greater can be achieved at 80°C under atmospheric conditions in as little as 4 hours of residence time. The process is selective for chalcopyrite over pyrite, generates near-quantitative levels of elemental sulfur, and is fully compatible with conventional solvent extraction and electrowinning of LME Grade A copper cathodes. In this paper, the fundamentals of the Galvanox ? process are reviewed, and selected results of batch leaching tests on various concentrate samples are presented and discussed.

Jan 1, 2007

"Coupon testing has been used to investigate stress corrosion cracking (SCC) of rockbolts in a laboratory based experimental program. This program has focused on the use of ASTM G39 three- and four-point bent beam coupon specimens, immersed in an acidified sodium chloride test solution containing hydrogen sulfide. The specimens were loaded to a range of stresses from zero, to just above the materials yield strength. It was found that only specimens above an applied stress of 580MPa failed by means of SCC, showing that rockbolts loaded to near their yield strength may be susceptible to SCC in-situ.INTRODUCTIONStress corrosion cracking (SCC) is a failure mechanism that affects material through the growth of hairline cracks when exposed to a corrosive medium while under stress (Jones and Ricker, 1999). SCC has been found to affect rockbolts in the Australian underground coal mining industry and has the capacity to cause the catastrophic failure of ground support systems, potentially leading to falls of ground in underground excavations, injury or death to mine personnel, damage or loss of equipment, and loss of productivity through the loss of roadway access (Crosky et al, 2002).Coupon testing utilises small scale samples that are intended to be indicative of the behaviour exhibited by a material in-situ (ASTM G39). The small scale, and usually high surface area to volume ratio of coupon specimens mean that they corrode at faster rate proportional to their mass, greatly reducing testing times. The small scale of the specimens allows them to be more easily prepared and handled, loaning them to mass manufacturing techniques.A previous study conducted by Vandermaat et al (2012b) into the use of three- and four-point coupon testing in-situ in an underground coal mine failed to result in SCC of the specimens. This paper serves as a follow up laboratory investigation in order to understand why these specimens did not fail. Previous studies into the SCC in rockbolts carried out by Gamboa and Atrens (2003) determined that rockbolt steel has a critical stress threshold of approximately 90% of the material ultimate tensile strength (800-900MPa). This study will focus on this critical stress threshold as a possible explanation for the lack of failure in the in-situ specimens (Vandermaat, 2012b)."

Jan 1, 2015

By Jonathan Tsang, Ali Merati, Jonathan Beddoes

Due to economic factors, many aircraft in service today have been operating for more than 30 years even though they were initially designed with a service life of 20 years. Improved damage management models are therefore needed for use in life prediction and management of the aging fleets of aircraft. Currently, the generally accepted procedure in fatigue life prediction methodologies is to back calculate the equivalent initial flaw size (EIFS) using established long crack growth data. However, it was observed from studies carried out at the National Research Council Canada that nucleation and short crack growth constitute up to -95% of the fatigue life. As a result, it seems that the significance of the short crack regime has been underestimated and must be further investigated and fully understood before an accurate holistic life prediction methodology can be realized. Unlike long cracks, local microstructural features such as grain boundary, grain size, inter-particle spacing, and texture play dominant roles in the behavior of short cracks. An extensive study has been carried out to evaluate different crack detection and monitoring techniques in the short crack regime for AA2024-T3. The results will be presented in detail.

Jan 1, 2004