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By Marcin Ziemski

This paper reports on an energy efficiency analysis completed as part of a research project looking at energy reduction opportunities in minerals processing operations. The plant discussed is a gold production facility owned by Newmont Gold in the Tanami region of central Australia. Due to its remote location, lack of nearby gas pipeline or power grid, the operation has been completely dependent on diesel fuel for its electricity generation and transport needs. The mine and processing plant use electrical power at a rate of 12MW to 18MW, resulting in a monthly electricity cost of over US$1.5M. The high cost of diesel combined with an impending power generation capacity shortage drove Newmont to undertake the energy efficiency study. An energy audit of the plant showed opportunities for significant energy savings through the strategic use of waste heat, fuel replacement alternatives and renewable energy sources.

May 1, 2007

By D. G. Eskin

"It is well known that it takes some time for the solid phase to completely dissolve upon melting, especially inside the defects of insoluble particles, e.g. oxides. Until then the oxides remain active solidification substrates in the case of subsequent solidification. It is also known that ultrasonic melt treatment causes grain refinement through activation and dispersion of solidification substrates (one of the mechanisms) and also accelerates the dissolution of solid metal in the melt. In this study we combine these effects and demonstrate that the introduction of an alloy rod into the matrix melt of the same composition results in significant grain refinement, this effect being increased by the ultrasonic vibration of the rod. The achieved grain size is comparable to that obtained by a standard Al–Ti–B grain refiner. All samples were cast using a standard TP-1 mould to enable correct comparison. The effect of the temperature range of the rod introduction, as well as the effect of ultrasonic vibrations are discussed.INTRODUCTION The fact that by introducing solid metal into the melt one can achieve structure refinement is rather well known. As early as in the 1930s–1950s a series of papers and patents have been published, showing the benefits for grain refinement when dissolving solid metal in the melt before solidification (Danilov and Neimark, 1938; Scheil, 1956). Later on this way of structure refinement was developed further and dubbed “suspension casting” or introduction of “internal chills” (Madyanov, 1969; Zatulovsky, 1981). The solid metal was added in a form of cut wire, cut sheet, or powder, with the resulting grain refining, elimination of columnar grain structure in ingots and castings of steel, copper and aluminium alloys. The underlying mechanisms have been suggested as (1) rapid cooling of the melt due to the latent heat consumption upon melting of the solid metal with the resultant melt undercooling and (2) introduction of many solidification substrates in the form of crystal fragments and active non-metallic inclusions (Danilov & Neimark, 1938; Balandin, 1973). A number of patents have been filed where either the same solid alloy or a master alloy with additions (e.g. Ti for Al alloy) is introduced in the amounts up to 50% (typically less than 10%) into the melt close to the liquidus temperature (Schmidt, 1966; Talbot & Soller, 1973, Krupp, 1974; Bondarev, 1979). The main reason that this technique is not widely used in industry is the possible incomplete dissolution of the solid parts introduced into the melt with ensuing inhomogeneous as-cast structure and potential defects. Also the selection of the temperature range where the technology works the best is not clear."

Jan 1, 2018

By Gary M. Bone

The autonomous control of vehicles interacting forcibly with their environment, such as dozers and tractors, is an unsolved and challenging problem. Forces and motions are inherently coupled between the tool and the means of vehicle propulsion. Furthermore, they are often operated within uncertain and unstructured environments, such as those encountered in underground mining. There is a growing industrial interest in the development of robotic vehicles to improve productivity, efficiency and safety in mining and construction. This paper focuses on the modeling and control of autonomous robotic dozing for a material removal operation. A dozing process model has been developed based on observations of both a fullscale dozer and a scaled-down version. The model characterizes the dynamic interactions between the blade position, material accumulation on the blade, material distribution in the environment, and the motions of the dozer. The dozing control objective is to remove the loose material as rapidly as possible by driving forwards at full power while automatically raising/lowering the blade in response to sensor measurements. Two different controllers were developed to meet this objective. The first controller is based on a set of heuristic rules, and the second is an optimal controller based on the dynamic model. An instrumented scaled-down robotic dozer and dozing environment, designed to emulate the full-scale operation, are used to implement the controllers and compare their performances over multiple dozing passes. Experimental results are presented showing that the model-based controller increased the material removal rate by 33% compared to the rule-based controller. Lastly, technologies for full-scale implementation are discussed, followed by proposed future work and conclusions.

Aug 1, 2013

By D. A. Wheeler, Rémi Tremblay

"INTRODUCTIONDuring the last few years, through Column Flotation Company of Canada ltd, the Centre de Recherches minérales has worked on the column flotation of coal, phosphate, feldspar, talc, graphite, copper, lead-zinc and diamond ores. The operating companies and prospective deposits were located in Canada and in other countries. Since these projects were financed by the concerned mining companies, all results remain confidential unless we obtain permission to publish. Three companies have graciously allowed us to use their information which I will describe in this text. These are the Polkowice copper mine in Poland, the North Coast Industries ltd graphite deposit and a talc company which preferred to remain anonymous. I will also describe our 2 inch column which was used for all tests. Data is also given on how to scale-up the 2 inch column to industrial size.Figure 1 presents a schematic of a flotation column. Feed, at a controlled rate and pulp density, enters at about 1/4 of the height of the column from the top. A controlled rate of air is bubbled into the bottom of column through a fine-holed sparger. The column volume between the feed point and the top of the sparger is called the recovery zone. Tailings, at a controlled rate, always slightly greater than the feed rate, discharges from the bottom of the column. This difference in feed and tailings flowrates is called the bias. The floated mineral is carried through the recovery zone on air bubbles which rise into the cleaning zone which is that column volume between the feed point and the overflow at the top. As the bubbles rise in this zone they are washed of gangue material by wash water which enters over the top of the froth layer. The froth layer is maintained at a given depth during flotation but this depth will depend on the froth cleanliness, for quite a bit of cleaning by wash water is accomplished in this layer."

Jan 1, 1988

By William J. Davis, R. Blair Hrabi, Sally Pehrsson, Amelia V. Logan, Ross Sherlock

"Abstract - The Meadowbank gold deposits are hosted by a series of polydeformed and metamorphosed auriferous iron formations located in the Neoarchean Woodburn Lake group, western Churchill province, Nunavut. The supracrustal rocks in the Meadowbank area consist of a thick sequence of intermediate-composition volcanic rocks with intercalated iron formation, ultramafic volcanic rocks, and quartzite to quartz arenite. U-Pb geochronology gives an interpreted age of 2711 ± 3 Ma for the host strata at Meadowbank.The intermediate volcanic rocks are predominately volcaniclastic and have a geochemical composition that is consistent with an active continental margin setting. Iron formation deposition was coeval with the intermediate volcanism, as indicated by incorporation of volcanic detritus in the chemical precipitate. The geochemistry of the iron formation indicates that it precipitated from a fluid that at one time was at high temperature (>250°C), reducing, and likely acidic. Intercalated ultramafic rocks rarely show spinifex textures and have trace element ratios that are consistent with mantle plume-related undepleted mantle asthenosphere, likely recording episodic mantle upwelling associated with rifting in an active continental margin. The contact between the ultramafic volcanic rocks and the overlying quartz arenite is a disconformity marked by a quartz pebble conglomerate. However, similar geology on the structural hanging wall and footwall of the contact suggests that the conglomerate does not represent a significant hiatus in deposition, and is more likely a prograding terriginous siliciclastic unit.Three metamorphic events are recognized. The first, M1, is a cryptic greenschist facies event that is pre-D2. The second event, M2, is a mid-greenschist to amphibolite facies, syn-D2 event. M3 is the last event recognized, and is a post-tectonic greenschist facies event that is regional but inhomogeneous in extent, possibly reflecting thermal aureoles around post-tectonic 1.7 to 1.8 Ga Nueltin granites. The structural geology of the area is complex with four phases of deformation recognized, two of which had a significant effect on the geometry of the deposit. All of these regional events are interpreted as Paleoproterozoic in age. Relationships between deformation fabrics and mineralization, as well as the overall geometry of the mineralized envelopes, suggest that the deposit formed during syn- to late-D2. Superimposed on the mineralization are D4 structural elements that postdate gold mineralization.The main control on gold mineralization is replacement of magnetite by pyrrhotite and pyrite in high-strain corridors. The composition of amphiboles and chlorites associated with gold mineralization is remarkably consistent and shows no spatial or temporal variation, suggesting that it was buffered by the iron-rich nature of the host rocks. The bulk metasomatic effect on the intermediate volcanic rocks is characterized by the addition of K2O and the loss of CaO, Na2O, and MgO, with little variation in the total iron content. The elemental losses are likely the result of destruction of feldspars, stilpnomelane, and ferroactinolite, which are relatively common in the unmineralized rocks, and the formation of sericite, chlorite, and grunerite."

Jan 1, 2004

By Frank Martonhegyi

"The objective of this paper is to review the coal basins in the Canadian part of the Western Cordillera to aid their understanding, and to aid in finding and proving places of economic coal mining potential. Coal occurs in eugeosynclinal basins in the Western Cordillera which evolved through three stages: -from systems of volcanic arcs in the Late Jurassic to mid-Cretaceous; -through an intermediate stage with deposition in increasingly restricted successor basins in Jurassic to Early Tertiary; -to a continental stage by the Eocene. Minor coal seams occur usually in late volcanic arc stage sediments bur they can be locally thick as they are on Queen Charlotte Islands. Successor basins usually show a marine-paralic-limnic evolurion. Signijicanr coal deposits occur in the tarter two sequences in the Whirehorse (Tantalus) and Bowser (SkeenaSusrur) basins. Currenr activities are intensive in the more accessible Bowser Basin, for example at Telkwa, Susrut River and on the Groundhog coal field. On Vancouver Island major coal seams occur in cyclic sediments, but the more accessible deposits are mined our. Exploration renewed recently in the less accessible northern part of the Island, for example Quinsam, for surface mineable coal. The Western Cordillera is a mosaic of allochtonous tectonic blocks. They originated from the south and were displaced northward by several hundred kilometres. Many Tertiary coal basins are related to strikeslip transcurrent faults along which the later part of displacement took place, for example the Dawson coal area in the Tintina Trench. Tensional and dipslip normal faulting also created or enhanced sites for thick peat accumulation. For example at Hat Creek 280 m of coal occur in a 550 m section. Secondary structures are often better exploration targets than the main fault zones. Pluvial and alluvial fan environments away from the main drainage are usually the favourable sites for thicker and cleaner coal deposition."

Jan 1, 1985

By K. Szczesny

This paper considers the integration of uncertain real-time logistics data for reactive construction scheduling. In order to manage a construction project efficiently, an accurate schedule representing the current project progress is inevitable. The quality and up-to-dateness of such a schedule depends on the availability of real-time data. Typically, real-time logistics data contain information about the availability of material, equipment and personnel as well as delivery dates and site conditions. The accuracy and inherent uncertainty depends on the location where the real-time data was acquired. Currently, the integration of such data into a construction schedule is a very time-consuming, manual and, thus, errorprone process. Therefore, this paper proposes a methodology that enables an automatic integration of such uncertain data into construction schedules. By integrating uncertainties into the existing schedule their impacts on the construction work can be evaluated. For this, discrete event simulation is applied. In order to model uncertain input parameters for simulation models this methodology applies the fuzzy sets theory. In combination with alpha-cut sampling technique, discrete model input parameters are obtained. By applying reactive scheduling with several discrete event simulation experiments, the results can be used to modify construction schedules according to agreed timeframes and costs. In order to demonstrate and validate the presented approach an example is conducted.

Aug 1, 2013

By A. R. Laplante

Gold recovery early in the flowsheet, typically from the primary grinding circuit, has seen significant advances in the past three years. Some of the advances achieved under the auspices of the AMIRA P420B Gold Processing Technology project are reviewed. The areas covered are gravity-recoverable gold (GRG) characterization, GRG behaviour in classification, gravity recovery simulation and the link between gravity recovery and cyanidation.

Jan 1, 2005

By J. -C. Sztuke, M. Cao

ABSTRACT Wash water and polyethylene oxide (PEO) were used in the flotation of quartz and coal. Wash water decreased entrainment of –15 µm quartz. The optimum superficial wash water rate was 0.05 cm/s. PEO also lowered entrainment. The combination of wash water and PEO led to a slight further reduction in entrainment. For 1:1 mixtures of –15 µm quartz and –300 µm oxidized coal, the combined use of wash water (0.05 cm/s) and PEO increased the separation efficiency from approximately 30% to > 70%, whereas wash water alone at 0.05 cm/s did not lead to a discernible increase.

Jan 1, 2014

By L. Chunpongtong

One of the challenges of mine planning is to determine the most cost-effective replacement time for aging equipment. The lifespan of equipment, such as haul trucks and shovels, deployed in mining operations varies due to the nature of the material and ground conditions in which it operates. For engineering economists dealing with aging equipment, the options become an economic trade-off between higher maintenance cost versus the cost of new equipment. The discount rate plays a significant role in this decision; the higher the rate, the longer the economically optimal lifespan. Therefore, the ultimate question is: ?How can the relationship between the discount rate and the economically optimal lifespan be expressed mathematically??

Aug 1, 2013

By J. Stiksma, K. Buban, J. Oftsie, R. Kalanchey, S. Sadykov, E. McConaghy

The Kazakhmys zinc refinery in Balkhash, Kazakhstan, which employs the Dynatec Zinc Pressure Leach Process, officially launched autoclave operations on December 27, 2003. The Kazakhmys plant is the world's first greenfields zinc refinery based on Dynatec's two-stage pressure leach technology. Production of zinc was realized on February 9, 2004, when the first cathode was stripped. Currently the plant start-up is ongoing, with progression to two-stage zinc pressure leach operation and ramp-up to full design capacity continuing through 2004.

Jan 1, 2004

By Renato Macciotta

The argillaceous formation known as the Opalinus Clay is host to the Mont Terri Underground Research Laboratory. The URL was developed to investigate the hydrogeological, geochemical and geotechnical properties of the formation. Underground excavations at the site are characterized by non-elastic and time-dependent deformations. Excavations trending perpendicular to the strike of the bedding presented relatively minor deformations, however, tunnels parallel to the strike of the bedding showed much larger non-elastic deformations. This paper presents an analysis of the measured response of a tunnel trending parallel to the strike of the bedding in Opalinus Clay. The measured convergence is compared to tunnel experience in weak rocks to assess the tunnel stability.

Jun 1, 2012

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 A. McLean, L. Gao, Z. Shi, Y. D. Yang, K. Chattopadhyay, G. F. Zhang

Levitation melting of metals is one of the emerging applications of magnetic and electric fields in liquid metal refining. The varying magnetic field generates induced current inside the metal droplet and leads to the Joule heating effect and Lorentz force against gravity. This contactless process can avoid contamination from the crucible and can be used to produce high-purity materials. Visualization of the levitation melting process is difficult, and thus generally investigated by mathematical modeling. In the present study, a three-dimensional mathematical model of metal levitation was developed using finite element method for proper understanding of the levitation process. The effects of harmonic magnetic field frequency, coils power input, and sample size on levitation nickel droplet were investigated. Temporal evolution of temperature fields were predicted directly though the model. Levitation and balance condition of the droplet were investigated as well.

Jan 1, 2015

By Pascal Turcotte

_ Introduction _ LaRonde _ Controlling Instability in Haulage Drifts _ Failure mechanism in drifts walls _ Failure mechanism in drifts back _ Field Behaviour of Support Elements _ The ?Hybrid Bolt? _ Conclusions

Feb 1, 2008

By Jarret Thomson

An understanding of groundwater flow is essential for many aspects of mining. This is especially true for the process of shaft sinking through the sandstones of the Manitou Falls Group in the Athabasca Basin of northern Saskatchewan. Experience has shown that the hydraulic conductivities of these sandstones can be relatively high, especially in zones containing natural fractures. To develop a better understanding of the inflow potential into a shaft, a laboratory testing program was undertaken to investigate the hydraulic conductivity of fracture core samples from the Manitou Falls Group. This program involved the measurement of hydraulic conductivities under steady-state flow conditions, while cycling the effective confining pressure across a span that is representative of in-situ conditions. The change in fracture aperture was simultaneously recorded at each confining stress level. It was found that existing relationships relating aperture and flow did not accurately capture the behavior of the samples tested. The effects of fracture staining and infilling were also investigated, and were found to have a notable impact on the hydraulic conductivity.

Jun 1, 2012

By B. S. Ignasiak, B. N. Nandi, D. S. Montgomery

The growing need to measure the extent of weathering of coking coal in storage and in transit prompted the comparison of the dilatation of coking coal on heating, which is known to be a sensitive index of oxidation, with the composition and volume of the gases produced by a mild pyrolysis of the same coal. It was found that the pyrolysis method had the advantage in that it could be used to study coking coals in advanced stages of oxidation, when the swelling properties had been largely destroyed. Of the various constituents in the pyrolysis gas, the most sensitive indication of coal oxidation was the volume of carbon monoxide evolved per gram of coal. For the coals examined, this index appeared to be at its best when the temperature of pyrolysis was approximately 35oC.

Jan 1, 1970

By Abhinav Karanam, Lukas Bichler

Yttria Stabilized Zirconia (YSZ) is a promising thermal insulator for high temperature environments due to its thermal stability and chemical inertness. As was demonstrated with other technical ceramics (e.g., Alumina), addition of Single-Wall Carbon Nanotubes (CNTs) to a ceramic matrix may significantly enhance the mechanical properties of the composite ceramic. In this work, 8 mol% YSZ with 0.2, 0.5 and 1wt% CNTs composites were prepared via Spark Plasma Sintering process. The densification, Vicker’s microhardness, specific gravity and microstructure evolution of the composites were investigated. The results suggest that the addition of up to 1wt% CNTs to YSZ yielded optimal combination of the studied properties. At higher addition levels, the specific gravity decreased and clustering of CNTs occurred, leading to poor densification and a relative loss of performance.

Jan 1, 2014

By F. Bosché

Previous research has shown that ?Scan-vs-BIM? systems are powerful to provide valuable information for tracking structural works (progress, quality, safety). However, the transferability of this capability to other construction areas such as MEP works has not been assessed so far. Comparatively, the construction of MEP systems, in particular pipes and ducts, tends to be more flexible with respect to the positioning of individual components, so that Scan-vs-BIM systems could be defeated when tracking MEP installation works. This paper presents recent results on the feasibility and performance of using a Scan-vs- BIM system to track MEP works. The approach followed is presented and then tested with two real-life challenging case studies were conducted simultaneously but totally independently in Canada and Italy. The results show that, as expected, pipes and ducts tend to be more loosely positioned than structural elements leading to a poorer performance of the Scan-vs-BIM system. Nonetheless, it appears that the system works well to assess the level of conformance of site installation works, providing valuable information for estimating emerging performance metrics like ?percent built as-designed?. In addition, the proposed system could also be useful to accelerate and thus reduce the cost of delivering as-built BIM models for in the case of new builds.

Aug 1, 2013

By K. Sakai, M. Miyaue, T. Aoki, T. Tani, S. Tanaka, N. Kudo

In the planning stage of a tunnel, due to limited technology in the geological survey and the financial restriction, tunnel supports are often designed from unsatisfactory information, and the tunnel construction is started. Therefore, "Information-oriented construction" is carried out in the construction stage, in which the design is rationally verified and modified by observations/measurements. Moreover, the ground conditions ahead of a tunnel face must be predicted for efficient and safe tunnel construction. The authors have examined effective prediction methods to the ground conditions ahead of a tunnel face under construction of mountain tunnels (Aoki et al., 2010) in view of the established method (Schubert et al., 1995). Though the prediction method of Schubert requires the displacement in the direction of tunnel axis, it is difficult to obtain its accurate data by the electronic distance meter. Then, we have proposed a method that uses tilt sensors installed at the tunnel crown near the face to obtain the slight tilting information. To measure inclination of the tunnel crown, this inclinometer was originally developed as a daily control measurement, such that the geological condition and its possible change behind the face could be detected early, and a steady advance and construction safety could be ensured. This paper describes the method of forward prediction mechanism and advantages of this suggested method. It then presents the typical results of a field verification test at a tunnel under construction and an example of evaluation of the ground conditions ahead of the face based on the 3D numerical analysis in three types of condition changes of ground deformation moduli.

Jan 1, 2015