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By A. Yousefpour, M. Hojjati, G. Chouinard

In recent years, high performance thermoplastic composites such as PEEK and PEKK have been developed for aerospace applications. These materials offer, among the other properties, high toughness and damage tolerances. These are semi-crystalline materials and their processing can lead to different crystallinity that in turn have some impact on the final properties. The effect of cooling rate on degree of crystallinity of PEEK is studied to identify the processing window for manufacturing. Samples were heated at the constant heating rate of 20°C/min up to 375°C (above melting point) and held for 10 minute. The enthalpy of the crystallization was measured at different constant cooling rates of 0.5, 1, 2, 5, 10, 20, 30, and 40°C/min. After cooling, the samples were heated at constant heating rate of 2°C/min using modulated DSC. At temperature between 90°C to 375°C, two endotherm peaks were observed. Results suggest that endotherm peaks are related to a melting and recrystallization phenomenon of one crystal morphology. However, the second endotherm peak could be associated with another crystal structure or morphology.

Jan 1, 2006

By Gustavo Brunello

Motor Failure Rates and Cost ? Motor failure rate is estimated: 3-5% per year. ? In Mining, Pulp and Paper industry failure rate is up to 12%. ? Sometimes process downtime costs are higher than motor ?? Motor failures are due: Electrical 32% Mechanical 31% Environmental 36%

Feb 1, 2008

By N. W. D. Davis

"As I have recently carried out some further research on the Navan lead-zinc deposit data while working in Michel David's research team, I should like to add a few comments on the paper- ""Universal Kriging for Ore-Reserve Estimation- Conceptual Background and Application to the Navan Deposit"", by M. Dagbert and M. David (CIM Bulletin, pp. 80-92, February 1976). The first comment is that since this research has been carried out, important new theoretical advances have been made which make for an easier application of geostatistics to the non-stationary case (see Matheron0l). This is the theory of intrinsic random functions of order k. With the aid of this theory, it has been possible to write computer programs which can carry out automatically universal kriging, although so far such applications have been largely confined to automatic contouring and not to mining problems. However, if approached with care there is no reason why these methods should not be applied to mining problems and, in this case, an automatic study has been done on this data."

Jan 1, 1976

THIS article describes the origin and details of a hydraulically operated switch to control the operation of an automatic underground pumping system. This system was installed in December, 1939, on the 2,350-foot level at No. 5 shaft of the Buffalo Ankerite mine. The pumping unit consists of an 8-stage centrifugal pump direct-connected to a 150 h .p., 2,200 volt motor. Pumping capacity is 200 gallons per minute under a 1,315-foot head and with a flooded suction. The control consists of a 200 amp., 2,200 volt oil-immersed starter with thermal overload protection, thermal protection on the pump, and a flow switch that is bypassed for 30 seconds after the pump starts. The 30-second time lag is operated by a relay mounted on the panel. There is a swing check valve in the discharge line of the pump which originally operated the flow switch by means of a connected outside lever which closed the switch as the check valve opened.

Jan 1, 1945

By Erol Yilmaz

This poster presents results obtained from an experimental test set-up called CUAPS (curing under applied pressure system) allowing to assess the performance and quality of cemented paste backfill (CPB) materials. CUAPS can be used for carrying out a series of tests: one-dimensional consolidation, saturated hydraulic conductivity, pore-water pressure dissipation, and curing under uniaxial stress. The poster presents CUAPS testing preliminary results including uniaxial compression tests (UCS) and mercury intrusion porosimetry (MIP). It was demonstrated that CUAPS-consolidated CPB materials cured under time-dependent stresses provide higher UCS values than standard mould (undrained and unconsolidated) CPB samples. This may be explained by the release of excess pore water within backfill that gives rise to a significant reduction in the total porosity of fresh CPB materials prior to hardening and thus, to higher mechanical strength (UCS) gain. The results obtained from MIP highlighted a good correlation between CUAPSconsolidated and mould-unconsolidated CPB samples. MIP results were also related to UCS values in order to predict the final CPB mechanical strength.

Nov 1, 2008

By Y. -B. Kang

New databases are being developed to provide the capability to evaluate the suitability of present and potential new Mg alloys for automotive applications through cost-effective calculations. An extensive and complete thermodynamic database is being prepared for Mg alloys formed from among 25 present and potential alloying elements. The database is being developed by critical evaluation, modeling and optimization of available phase equilibrium and thermodynamic data. It contains model parameters giving the thermodynamic properties as functions of temperature and composition. Using the FactSage thermodynamic software, users can access the database to calculate the amounts and compositions of all phases at equilibrium at any temperature and composition or to calculate any phase diagram section in multicomponent alloys, to follow the course of equilibrium or non-equilibrium cooling, to calculate corresponding heat effects, etc. A database of densities and lattice parameters of Mg alloys and intermetallics (as functions of temperature and composition) is also being developed in order to permit the calculation of volume changes during cooling and phase transformations, c/a ratios of the hcp phase, etc.

Jan 1, 2006

By Paul J. Beck

The impact of mining development on the environment can be minimized through comp careful construction and accurate monitoring. Key to meeting these objectives is t information at all stages of design, development, operation and decommissioning. This paper will describe cost-effective means of gathering and managing reliable fiel groundwater flow and surface water regime within and surrounding the mine site, as localized contaminant plumes associated with mine operations, and monitoring ground quality. Recent research has led to the development of inexpensive, easy to install syst sampling/monitoring from different zones within a single borehole. Advances in elect developed small diameter probes and pumps for measuring water levels and taking wat continuous monitoring stations in remote areas can be colldeacttaeldo gaguetrosm aatnidc adlolwyn luosaidnegd from a central facility using telemetry systems powered by direct, battery or solar radio frequency, landline or cellular telephones, and satellite. Two case studies will illustrate the use of datalolgagregres sacnadl et eblaesmient rwyi dien mao nitoring sc and the use of multilevel samplers for managing a contaminant plume.

May 1, 2004

By I. Takahashi

Recently, electronic devices have become smaller for some kinds of electronic devices, thermal dissipation and electrical conductivity of conventional Fe based alloy becomes insufficient. We selected the Cu-Fe based alloy CDA19400 and optimized the wire manufacturing process. Precipitates during aging treatment were observed by TEM. The size and distribution of the precipitates varied according to solution treatment temperature. With solution treatment at 950°C, the precipitates of y-Fe as fine as 10 nm were distributed dense in the copper matrix with coherency. For the solution treatment at 750°C, y-Fe of approximately 200 nm was observed. Comparing heat resistance of drawn wires, the material at 950°C treatment was superior. Electrical conductivity decreased from 63% IACS upon aging to 29% IACS by drawing. It is considered as particular phenomena for wires where materials are drawn with high reduction ratio. By the optimized manufacturing process, we successfully developed a new wire that has superior in strength, thermal conductivity, electrical conductivity, heat resistance and repeated bendability.

Jan 1, 2007

By H. Stillman

The International Copper Association, Ltd. (ICA) is responsible for guiding strategy and policy, and funding international initiatives that help deliver the benefits of copper around the world. ICA's technology initiative supports this mission by funding pre-competitive technology development and accelerating the commercialization of new copper-related technologies. The R&D portfolio includes some projects that defend existing applications such as plumbing tube and data cabling, but the majority of projects are designed to enable new applications for copper. The current technology portfolio is focused on leveraging copper's unique electrical, thermal, mechanical and antimicrobial properties to define and expand the role of copper in areas poised for future technological growth: reducing disease transmission, sustainable energy generation, reducing the environmental impact of production processes, and in increasing energy efficiency. Projects related to these areas are conducted at qualified external organizations including universities, early-stage firms, and large OEMs worldwide. This talk will provide an overview of ICA's technology initiative's principles, projects and partnerships to stimulate the audience to think about copper-related innovations.

Jan 1, 2007

By L. Cifuentes

The temperature dependence of: a) electrolyte density, viscosity and electrical conductivity and b) the equilibrium constants of formation for all relevant species have been determined as part of an effort to model the operation of a copper electrowinning cell based on reactive electrodialysis. The studied ranges were: 1.01 to 1.25 g/cm3 for density, 4.9x10-4 to 16.4x10-4 kg m-1 s-1 for viscosity and 0.02 to 86.0 Sri m-1 for electrical conductivity. Density and the electrical conductivity of the catholyte increased linearly with temperature whereas the viscosity increase was exponential. The main effect of ionic speciation was to decrease the electrical conductivity with increasing metal concentration due to ion association (mainly the formation of bisulphate ion) which lowered the concentration of protons (the most mobile species) in solution. This effect was specially noticeable in the anolyte. Mathematical relationships with correlation coefficients between 0.959 and 1.000 have been found for all the studied variables.

Jan 1, 2007

A series of small scale tests have been conducted to evaluate the effect of micro-fracture development, imposed by blasting, on the material properties of the rock as well as its resistance to crushing and grinding. The uniaxial compressive strength, tensile strength, Poisson?s ratio, P-wave, Swave velocity, point load test index, crushing and grinding work indices were evaluated for samples without any blasting load and for samples which had received a variety of blast loads ranging from a single impact with low strength detonating cord, to combination of impacts at different times and significant impacts with powder factors close to those used in practical blasts. It was shown that the rock mechanics parameters change even at low impacts, suggesting easier crushing of the rock. Damage values appear to be affected by timing as stress wave superposition affects the damage process. Fragmentation is achieved at higher impact levels while work index modification of the fragments is also observed when high powder factors are used, suggesting improvements in grinding.

May 1, 2003

By Peter A. Witt

Highland Valley Copper is a conventional truck-shovel mining and flotation concentrator operation located some 75 kilometres southwest of Kamloops, B.C. (Figure 1). The ore is located within a porphyry copper deposit and is mined at a rate of 135,000 metric tonnes per day from two separate open pits. The nearby mill produces concentrates containing 375 million pounds of copper and 5 million pounds of molybdenum metal yearly. In the Valley pit, head grades are roughly 0.40% Cu at a 0.23% Cu equivalent cut-off. The Valley pit strip ratio currently sits at 0.55:1 with waste quantities made up of separate rock and unconsolidated overburden units. From the mill, concentrates are trucked to nearby Ashcroft and then hauled by rail to ocean port facilities in Vancouver. The mine employs 950 persons and is planned to operate until 2009. The operation is a partnership between TeckCominco with a 63.9% interest, BHP Billiton holding 33.6%, and others 2.5%. Management is shared by the two principal owners and directed by a management committee.

May 1, 2003

By R. W. Nice

"For many decades the incidence of a highly active graphite-like ore has plagued the McIntyre mine. This ore acts as a precipitant of the gold complex immediately upon formation of this complex. The gold is subsequently discharged with the tailings.Many different methods have been devised by various researchers all of which proved inapplicable for the McIntyre problem.Recently, McIntyre personnel, through their own research, developed a flowsheet. This circuit should give an overall recovery of 36% which is below the 94% experienced in the mill at present. Therefore, less revenue would arise from treatment of these ores. On the other hand there exists a possibility of more efficient mining methods in some of this ore thus allowing more economic recovery.INTRODUCTION This paper has been prepared to serve two purposes:i) To propose a method of recoverying gold from a sizeable orebody at the McIntyre mine at Schumacher.ii) To summarize and present the many methods suggested to solve a very old but very real mineral dressing problem familiar to the industry as long as cyanidation itself."

Jan 1, 1971

By Tiago Webber

Mineral resources estimation comprises basically two stages: (i) data collection, analysis and validation, and (ii) the estimate of the grades and tones of the deposit. The most applied method for sampling survey in mineral exploration is rotary drilling with total core recovery. High drilling costs make borehole geophysical logging attractive to obtain the maximum possible information from each borehole helping to understand ore intersections, grades variability, limits of the deposits and continuity of the mineralization. In this paper, borehole geophysical logging was used to enhance the sampling survey and to derive grades indirectly (without lab analysis) with a certain amount of uncertainty. Indicator kriging (IK) was the estimation method used, as it is adequate to incorporate the uncertainty associated with the geophysical derived grade values. The results were compared to the conventional procedures using grades determined via core analysis and ordinary kriging. Borehole geophysical logging proved to be efficient to define the essential features of ore deposit and IK provided results with acceptable precision and accuracy if compared to the model provided by ordinary kriging.

Oct 1, 2009

By Brian O'Hearn, Doug Hanson

"The most commonly used tendon supports in the Sudbury area include rock bolts, rebars, friction anchors and cable bolts. Due to the fact that these tendons are physically different and employ different anchoring systems they offer varying degrees of stiffness, yield ability, load capacity, anchor dependability and energy absorption. These differences coupled with variable rock mass and changing stress conditions have made it challenging to engineer the design of an effective support system. By tapping into the knowledge and experience gained by ground control practitioners, an empirically based rating system has been assembled that offers a guide to designers of support systems when choosing the most effective tendon support over a range of rock mass and stress conditions.A methodology referred to as support planning can be used to design support systems whose rehabilitation costs will be minimized. The use of multiple tendon types in anyone support layout is advocated, particularly when the stress state of the rock mass to be supported is expected to undergo a change."

Jan 1, 1995

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 ecision making and performance assessment.

Nov 1, 2011

By A. J. Hyett, N. Hedrick, J. Blackall

The Garford bulb anchor is a modified cable geometry developed and patented by Garford Ply Ltd. of Australia, and which has recently become widely available in Canada. It is produced by deforming the seven wires (including the central kingwire) of a standard cable into a bulb" (Fig. 1). Laboratory cable pull tests indicate that the bond capacity of the 25 mm Garford bulb anchor is comparable to the nutcase cable, in excess of the birdcage cable, and significantly higher than standard 7-wire strand. Its comparative advantage over the latter is most significant for tests at low radial confinement and high water:cement ratio grout, which corresponds to operational conditions of low quality rock (i.e. weak, highly fractured rock masses, foliated hanging walls, failed ground, etc.) and poor installation quality control (perhaps the most common explanation for cable bolt failures). It is under such conditions that cable bolting is often ineffective. The most impressive result is that for a reduction of the effective rock mass modulus by a factor of five, the Garford bulb cable capacity remains virtually unchanged.

Jan 1, 1995

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 G. Dubé, A. Leclerc, P. Quinn, G. E. Agar, J. Y. Clouthiér, J. D. McLaughlin

"Gold dissolution by cyanide requires the presence of oxygen which is usually supplied by sparging compressed air into the gold containing slurry. For those ores that contain certain obnoxious substances that consume oxygen, maintaining the required minimum level of dissolved oxygen can be troublesome. One of the most economical solutions to the problem of low dissolved oxygen, especially in plants that have air compressors installed, is to enhance the rate of oxygen mass transfer.The oxygen mass transfer rate was measured in a two phase system using two different sparger arrangements, and with addition of a frother that is known to reduce the bubble size produced by the sparger. The common sparger system was shown to be inefficient compared to a readily available but under utilized method of gas dispersion which introduces air directly below the reactor turbine. Transfer of this technology to an operating plant confirmed the beneficial effect of the improved sparger system. The addition of the frother did decrease the bubble size, but it also reduced the oxygen mass transfer rate."

Jan 1, 1993

By J. E. Nelson

This paper will examine the problems inherent in matching grinding mills with electric motors through connecting elements such as clutches. Emphasis will be on the uncertainties of mill torque and power demands and the need to recognize these if dependable, safe designs are to be obtained.

Jan 1, 1972