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By Ken J. Brouwer

Stillwater Mining Company commenced construction and development of the East Boulder underground mine in 1998. This new PGM mine is situated adjacent to the East Boulder River approximately 35 miles south of Big Timber, Montana. Project planning and development incorporated detailed collaboration between the regulatory agencies, concerned citizens and mine personnel. A unique ?good neighbour agreement? was established with a local environmental group who have become actively involved in the review of ongoing site development and the implementation of environmental and compliance monitoring. Environmental management systems allow for integrated management of tailings, waste rock and water in order to minimize surface disturbances and to prevent adverse impacts to the East Boulder River. Long-term site development plans contemplate implementation of comingled waste rock and paste tailings. Water management capabilities allow biological treatment of all excess mine water in order to reduce nitrogen loadings prior to land application disposal by means of spray evaporation, snow making and land application. The comprehensive waste and water management plans have also been integrated with staged mine development and interim reclamation requirements.

May 1, 2002

By D. Y. Li, C. D. Ma, T. Zhou, T. J. Cheng

In this paper, a number of experimental tests are carried out to study the strength difference on rectangular prismatic marble specimens with different height-to-width (H/W) rations. The specimens have a nominal size of 45×15 mm in the compressive cross-section (W×T) and different heights (H = 22.5 mm, 45 mm, 60 mm and 90 mm). It is to say that the height-to-width ratios are equal to 0.5, 1.0, 1.33 and 2.0, respectively. The quasi-static uniaxial compressive tests are finished by a servo-controlled INSTRON machine (the strain rate at about 10-5/s), and the dynamic compressive tests are finished by a diameter of 50 mm cylindrical SHPB apparatus (the strain rate reaching about 101/s). The rock failure process of marble specimens is captured by a high speed camera in order to distinguish the fracture propagation behaviour. It is found that the compressive strengths increase when the H/W ratio of marble specimen changes from 2.0 to 1.0 due to the end clamping effect both for quasi-static and dynamic loads. However, when the H/W ratio changes from 1.0 to 0.5, the apparent compressive strengths decrease both for the two loading conditions. The strength decrease of short marble specimens may be attributed to the change of failure mode from shear to slabbing, which can be identified by the fracture patterns of the specimens. Based on the uniaxial compressive tests, the slabbing strength of the marble was found to be about 40% of its UCS for the specimens with a nominal height-to-width ratio of 2.0. In addition, it is found that the dynamic increase factors (DIF) are affected by the specimen’s aspect ratios. It implies that the same aspect ratios should be used to compare the dynamic and static compressive strength of rocks. Meanwhile, both the static and dynamic tensile strengths of the marble are obtained by the Brazilian disc tests. The ratio of the dynamic tensile strength to the static tensile strength of the marble is about 2.68.

Jan 1, 2015

By M J. Daniel

Comminution is the science of size reduction of brittle materials. It is integral to mineral extraction and is one of the most energy intensive processes in the mining industry. There are a number of tests used to quantify the strength of ore, which are then used to size the AG / SAG mill in circuit design. The calculated energy utilized for breakage in these devices is based on the assumptions that the materials treated are of average shape and that the processing equipment is designed to break the ore as efficiently as possible under the given operating conditions. In drop weight tests, it was found that shape significantly influences the measured rock strength. Controlled experiments with variations in blends of rock shape show that mill throughput increases with the addition of weaker shaped rocks.

Jan 1, 2012

By R. G. Achter, E. Wilson

"This paper describes the work undertaken to renovate the Pipe Open Pit drainage system, incorporating measures to improve effluent quality. It describes the technical feat of drilling an l l-inch-diameter hole from the bottom of the open pit for a distance of 1100feet to intersect an underground drift. An innovative method of checking the inclination of this hole is also described. The paper outlines the construction required on the 1500-foot level of the underground mine to facilitate water impoundment and slime settling, as well as the instrumentation for control of water flows. IntroductionThe Manitoba Division of Inco Metals Company operates two mines-an underground mine at Thompson and an open pit at Pipe. The Pipe Open Pit is located 20 miles southwest of the City of Thompson, approximately 400 miles due north of Win nipeg(Fig. 1).Surface diamond drilling of the Pipe ore body was sta rted in 1959. In 1961, a shaft was sunk to a depth o f 1,570 feet to carry out further exploration work and obtain bulk ore samples for metallurgical testing. Site preparation to mine the upper portion of the orebody as an open pit was initiated in 1966 and by late 1967, the removal of silt and clay overburden was in progress. The contractor completed the dredging in the fall of 1969. Over 12 million cubic yards of muskeg, clay and silt was removed, which in some places was 150 feet deep over the orebody. Production began in early 1971, by which time the top three benches of rock had been excavated and the orebody exposed.The Pipe No. 2 Mine main shaft was started in 1970 and completed in 1973 at a depth of 3,160 feet. Development for exploration purposes was carried out on the 1500 and 2460 levels, and permanent pumping facilities were installed.The surface dimensions of the open pit are 2,200 by 1,600 feet, with the long axis striking northeast. The walls are designed with a 45- to 50-degree slope and the ultimate design depth is 720 feet. The present depth of the pit is 520 feet and production capacity is 6,800 tons of ore per mine day."

Jan 1, 1980

Why innovate? ? How are we doing in Canada? ? How can we do better? ? Why now? ? What?s next? ? Lowering production costs ? Improving productivity ? Increasing value-added ? Discovering new mines, extending life of existing ore bodies ? Reducing environmental footprint ? Improving health and safety

May 1, 2008

By T. Krumins, L. Zunti, R. Frischmuth

Titanium and titanium alloys are commonly selected for pressure oxidation autoclave vent piping and pressure control valve components, as well as autoclave internals, in high-temperature operations. In a vent application, titanium ignition risk is reduced by limiting oxygen concentration, and preventing high gas velocity gas impingement on surfaces. Oxygen concentration is dependent on the autoclave pressure and temperature conditions and therefore titanium ignition risk is dependent on standard operating procedures, and process control interlocks and permissive conditions. It is not uncommon for standard controls to be deficient during atypical operating conditions, or for operations to deviate from the operating procedures, increasing the potential for titanium ignition incident. Titanium ignition risk caused by elevated oxygen concentration in autoclave vent systems can be reduced with the introduction of an online autoclave overpressure calculation and the configuration of associated interlocks and permissive conditions.

Jan 1, 2014

By T. R. Madhavan

The development of contact angles on highly polished ?uraninite surfaces, using sodium oleate and dodecyl ammonium acetate as collectors, has been studied at different collector and hydrogen ion concentrations. It was found that sodium oleate in acidic media (up to a neutral: PH) and dodecyl ammonium acetate in neutral and alkaline media give good contact angles. It appears that the combined forms of these collectors, viz., oleic acid and free amine, are more important in effecting contact. W ITH the emergence of uranium as a strategic metal in the last fifteen years, considerable effort has been directed toward the commercial recovery of uranium from its ores. This has resulted in the development of a uranium technology. It is only in recent years, However, that fundamental data regarding the floatability and surface properties of uraninite and ?pitchblende have been elucidated by different methods. Contact-angle measurement is one of the important tools for tl1e evaluation of the conditions of floatability

Jan 1, 1964

By P. Reyes

The start up and operational optimization of the No. 3 Oxygen Plant at the Caletones Copper Smelter of the Codelco - Chile El Teniente Division is summarized. In addition, the economic impact of such optimization on the production cost of oxygen and others aspects associated to the operational robustness as well is detailed.

Jan 1, 2007

By J. C. Ingles

"A survey of possible methods for controlling cyanide concentration indicated that the simplest method would involve the use of a potentiometric technique. Such a method was suggested by a paper from the laboratory of Mines Safety Appliances, which described a method for determining hydrogen cyanide in air. In this application, the cyanide was absorbed in caustic and a silver electrode immersed in the caustic solution provided a measure of the cyanide concentration. However, our attempts to use the silver electrode in this simple manner to measure the cyanide concentration of solutions were not very successful. A study of the mechanism by which a silver electrode responds to cyanide concentration made it evident why this simple procedure is not satisfactory.Basically, the silver electrode provides an indication of the free silver ion concentration of a solution, and generally speaking, ignores the other ions' present. It can be used to measure an anion if this anion complexes silver. This technique has been used in complexing studies to determine the activities of such anions as acetate, citrate, oxalate and chloride. To do this, the electrode has to be placed in a solution which initially contains a known concentration of free silver ions. Addition of the complexing anion causes a drop in the free silver ion concentration and hence a change in the potential of the silver electrode. The change in potential can be expressed in terms of the concentration of the complexing anion, and used to indicate its concentration in the solution being analysed. The determination of chloride-ion by a silver-silver chloride electrode is an example of an application of this technique. The solubility of the silver chloride with which the electrode is coated provides the initial free silver-ion concentration. Depression of this free silver-ion concentration by the presence of the excess chloride ion of the sample solution results in a change in the potential of the electrode which is proportional to the chloride-ion concentration."

Jan 1, 1965

By X. W. Yi, Z. J. Li, G. W. Ma

In this paper, the compressive strength and failure patterns of reinforced cemented paste backfill (CPB) were studied aiming to promote the stability of backfilled stopes. The concept of ductile backfill was proposed and a series of unconfined compression tests were carried out on both non-reinforced and reinforced cemented paste specimens. Portland cement (3% to 5% by weight of tailings) and five different types of ductile materials (0 to 0.5% by weight of solids) were employed in this experiment for the specimen preparation. The test results showed that inclusion of ductile materials enhanced the unconfined compressive strength (UCS), reduced the post peak stress loss and transformed the failure behaviour of specimens from classical brittleness to ductility. The strength of CPB reinforced with different proportions of polypropylene fibres was compared. The stress-strain curves illustrated that both cement and fibres contributed to the increase of UCS, but higher strain values at the peak stress were achieved by fibre reinforcement. CT sliced images acquired from X-ray computed tomography (CT-scan) demonstrated that the reinforced specimen developed irregular crevices at the edge of cross sections and gained the capacity of bearing large displacements owing to the mobilised tensile strength of fibres. It leads to the potential of avoiding unexpected falling blocks of CPB when adjacent mining occurs. This finding highlights a strategy to improve the self-supporting capacity of the fill mass with less cement usage and reduce the ore dilution rates when excavating to adjacent stopes.

Jan 1, 2015

By K. Ogawa, T. Yokoyama

Hydraulic fracturing technique, an applied technique to cause tensile fractures to rock by injecting water pressure to a certain closed section of the borehole, is a measurement method of in-situ rock stress. This technique has the highest track record for techniques used in sub 1000 meter. A feature of this technique is comparatively simple and easy for in-situ stress measurement, because the measurement is applicable when a drilled borehole is available. The predominant advantage of this method is that elastic constants such as Young’s modulus and Poisson’s ratio are not required for determining the value and direction of initial stress. The factors to determine the stress state are the water pressures of re-opening and shut-in of fractures around the borehole wall and its directions. With conventional methods, however, the accuracy of the derived stress states from the observation equations was often adversely affected by the lack of consideration of the remaining water pressure in fractures and insufficient stiffness of the pressurization system. We have developed a new hydraulic fracturing system based on a new test method concept overcoming these defects, and applied to a 300 meter deep borehole in granite. The most important improvement of the new system is an employment of a syringe pump which enables an accurate flow control of fluid with less than 1ml/min in the pressure of 30MPa. Therefore the new test system has a quick response for pressurising in the interval zone, and the measured data was confirmed extremely accurate.

Jan 1, 2015

By L. E. Collins

"In western Canada, many new wells contain a significant fraction of H2S. As well, many older wells become increasingly sour over their operating lifetime. For these reasons, there has been increased demand for linepipe and casing for sour service applications in recent years. This paper will review the metallurgical factors which must be considered in designing steels for such applications. IPSCO’s development of linepipe and casing, and experience in fabricating products to meet test standards specified for sour service applications will be summarized. IntroductionWestern Canada produces the majority of Canada’s domestic crude oil and natural gas. A complex system of pipelines has been built to gather the oil and gas from the fields for transport to refining and/or cleaning operations. The gas carried in these pipelines can be either sweet or sour (i.e. containing no H2S or containing H2S) depending on the nature of the field from which it came. Many new fields contain a significant fraction of H2S and many older fields become more sour as their time in production increases. This uncertainty regarding product condition influences the user’s choice of materials for both casing and pipeline applications.It is well known (Merrick, 1989) that hydrogen induced cracking (HIC) will occur in steel when three conditions exist simultaneously: (1) the presence of H2S gas, (2) moisture, and (3) a susceptible material. Steelmakers can only address the latter of these factors. Development of steels to meet test requirements of sour service has been a major focus of IPSCO’s development work for several years."

Jan 1, 1998

By Qing-Xun Low

Ni current collector has excellent electronic conductivity and mechanica, properties. However, nicke, cannot be used in H2S-containing syngas SOFCs due to sulfur poisoning and coking. Copper coated nicke, is prepared by electrochemica, deposition. XRD, SEM, and EDX techniques are used to characterize the samples. After high temperature treatment in syngas containing, the coated samples exhibit high resistance of coke formation and sulfur corrosion compared to pure nickel. Therefore, copper coated nicke, is a promising anode current collector for H2S-containing syngas SOFCs.

Jan 1, 2010

By Jean Robitaille

La découverte du gisement du puits Penna a nécessité une révision complète de tous les circuits du concentrateur Laronde pour permettre, premièrement, l?adaptation du procédé à la nouvelle minéralogie et deuxièmement, l'accroissement du tonnage de 1800* à 4500 t/j. Aux circuits existants de broyage, de flottation du cuivre, de cyanuration et du charbon en pulpe, les circuits suivants furent greffés : broyage semi-autogène, flottation du zinc, manutention des concentrés (épaississage, filtration, entreposage et chargement automatisé), décantation à contrecourant et précipitation au zinc, destruction des cyanures et remblai en pâte. Cet article se veut une revue des différentes étapes du projet d'agrandissement du concentrateur qui se sont effectuées par phases progressives de 1997 à 2000. De plus, une description des nouvelles technologies sélectionnées et implantées est présentée.

May 1, 2001

By D. Murray

A 2-hectare uranium tailings area has been reclaimed. The exposed tailings of 1.4 hectares were capped with glacial till and vegetated with grasses and legumes. The water running through the tailings was diverted around the tailings in a line ditch and treated with sodium hydroxide and barium chloride. Difficulties occurred in placing the till capping because of the low bearing strength and the uneven surface of the tailings. This led to varying thicknesses of till and the need for manual labour in some areas. Total reclamation costs were $32,200, with vegetation establishment costs at $13,700 per hectare. This report provides a record of work for use in assessing the long-term suitability of these treatments.

Jan 1, 1979

By Liangtian Liu, Tie Ou, Guangqiang Li, Chenghuan Yu

For stabilizing the production of containing nitrogen steels, a study on nitrogen absorption behavior of killed molten steel has been carried out by means of the RH vacuum device in which nitrogen was used as a driving gas. The results showed that there was an increase of nitrogen content in molten steel under vacuum processing but the rate of nitrogen absorption was slowed down by the surface active elements. Therefore, a kinetic equation for nitrogen absorption of molten steel with apparent first order reaction was derived by constructing a modified model in which the adsorption of closed surface site was taken into account. The experimental results confiimed that the calculated values agreed with the observed ones. This model is suitable for the prediction of nitrogen adsorption operation for containing nitrogen steels.

Jan 1, 2004

By A. Carbonari

In order to gain competitiveness and compete at a global level, construction companies should improve their efficiency. The problem is even more relevant in the construction field, whose work processes find it hard to evolve towards new automated methods and techniques in the management field. For that reason, this paper suggests how construction companies could apply new technologies to implement automated management of environmental hazards. Based on a survey regarding the environmental risks presently experienced in construction sites, noise and dust were considered two of the main hazards. So in this paper a networked system for real time remote monitoring of the spatial distribution of dust in construction sites was developed. Such a system would relieve builders from the commitment of on-site surveys, allowing for a continuous monitoring of the site conditions and of the real exposure of each worker and pass-by to the pollutants generated by construction works. The main system requirements considered are: easy to deploy, reliable, as accurate as needed to be able to send real-time warnings and store a good estimation of the real exposure to which involved people have been subject to. So far the research produced a prototypical hardware for dust monitoring made up of wireless sensors which can be easily deployed on site. The sensors were calibrated by means of laboratory tests, where their measurements were compared with those collected by means of highly accurate instruments, which were taken as a reference. Thanks to these experiments, calibration curves for the sensors were worked out, showing also the measurement range of the sensors.

Aug 1, 2013

By A. Zangooi, J. A. Finch

Flotation is a separation process based on the collection of particles on the surface of bubbles. Flotation machines disperse air into bubbles using a variety of techniques. The characteristics of the bubble population are strongly affected by the selection of frother type and concentration. As metallurgical results depend on the bubble distribution, the measurement of frother concentration is vital to understand and control performance. A previously developed colorimetric technique was refined to work with low solubility frothers and to increase daily analysis rate. Field-testing demonstrated that the method is robust, reliable and accurate. As well as relating frother concentration to gas dispersion measurements, the results can be used to answer operational questions including: how well a frother dissolves, how reliable and stable frother delivery is, how evenly frother is distributed down a bank, and whether frother distributes between the pulp and froth zones. Some of these points are illustrated from plant experiences. Advances in Mineral Processing Science and Technology Proceedings of the 48th Annual Conference of Metallurgists ofCIM Sudbury, Ontario, Canada Edited by

Jan 1, 2009

By Emmanuel Henry

The Kiruna Mine, operated by Luossavaara-Kiirunavaara AB (LKAB), is a large-scale sublevel caving operation located in Arctic Sweden. Iron ore is extracted at a rate of 60 000 tpd from a four-kilometre long, 80-100 m thick and 60-degree dipping orebody. Actual production depth is 800 m under the top of the footwall and about 550 m under the average regional ground level. Because no support is left between the footwall and the hanging wall and despite the relatively low mining depth, extraction results in the formation of a huge stress shield modifying the original stress field and concentrating it just beneath the mining level. Effects of stress concentration on the rock mass are monitored through field observations and a seismic system. Severe stress-induced deterioration of openings is visible to a certain radial distance from the mining level: pillar crushing and fault slips are more and more common and extended. The seismic system, installed in collaboration with CANMET, confirms the field observations and completes them in the rock mass: fault slips and major seismic events are recorded. The system proves its effectiveness to outline the extension of the dynamic response of the rock mass, which actually seems much larger than field observations let think.

May 1, 2001

By S. Sundararajan, J. Brousseau, P. Bocher, M. Galopin, N. Barka

This research is committed to the prediction of the hardness profile produced by induction heating, using a computer-modeling software. The paper presents the simulation of the induction hardening process to analyse the sensitivity of the induction parameters on the hardness profile of a low alloy steel specimen. The developed numerical model includes the coupling effect between electromagnetic and thermal fields, and takes into account the non linear behaviour of the material properties. The study applies an enlightened experimentation method to build the feasible domain of the process and to achieve predictive empirical modeling. The ultimate goal is to replace the trial and error method that is usually used for the development of new parts, by costless experiments with the numerical model. Further development of this approach will lead to the computation of the residual stresses and finally to the assessment of the mechanical properties of the part. The end result will be the ability to shorten the development time and to improve the quality of the hardened part.

Jan 1, 2006