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By J. Ramirez-Castro, J. A. Finch

"Galena is the finest component of the product of a closed-circuit grind treating a lead-zinc ore, largely due to preferential recycling of this high-density mineral by the cyclone. For example, at the Pine Point Mines concentrator, for ~ 55% -200 mesh over-all, the galena will be close to 95% -200 mesh. This sliming of the lead can limit recovery, selectivity and dewatering. A proposed circuit modification to reduce the sliming is to incorporate a unit cell. A simulator was constructed to study the No. 3 grinding circuit at Pine Point modified by a unit cell on ball mill discharge (BMD).The simulator used a cumulative size basis rate-of-breakage with plug flow ball mill model, the parameters being obtained by laboratory grinding tests. Flotation and the cyclone models used a cumulative recovery/size matrix. The behaviour of each mineral, galena, sphalerite, pyrite and calcite/dolomite, was simulated. Simulation was adapted to a programmable calculator. A close fit to the existing circuit performance at two tonnages and mineral mixes was established.The simulator showed that the modified circuit could significantly coarsen the Pb grind, from 95% to —50% -200 mesh, depending on recovery, without substantially altering the size of the other minerals. The other principal findings were: compared to laboratory flotation tests on existing circuit BMD, the unit cell concentrate (CONC) will be coarser and markedly lower in grade; relatively low unit cell stage recoveries are desirable, because the cyclone scavenges the tail to give a circuit recovery which is higher than the unit cell stage recovery; unit cell stage recovery should not exceed the cyclone stage recovery, as the latter is the maximum circuit recovery; low unit cell stage recovery helps offset the disadvantage of the high flow at BMD; other high-density minerals will also be scavenged into the CONC, as illustrated by pyrite, making CONC quality difficult to maintain; density control of BMD flotation does not greatly alter feed density to the cyclone or ball mill.Possible plant metallurgy is forecast for a CONC diverted to final lead concentrate."

Jan 1, 1980

By R. Lovat, J. A. Hunter

"The design, development, and verification of the Lovat 7.6metre diameter full-face tunnel-boring machine is reviewed. Programmatic and technical challenges are outlined with a review of the specifications and the design to meet these requirements. Subsystem designs are presented for the waste material removal, ventilation, cutter head, structural support, advance technique, water removal, and interfaces with the Donkin-Morien Mine. The techniques used to verify that the design meets the requirements is by testing in the Lovat factory and in the field. Certification of the machine for use in a methane environment is discussed.IntroductionStudies have concluded that the average annual worldwide tunnel construction is 500 kilometres at an estimated average co st of $3,400 U.S . per linear metre. The total market value of the tunnelling industry is estimated as approximately $1.7 billion U.S. per annum. Of this, the current market for tunnelboring machine excavation is approximately $270 million U.S. per annum worldwide with a further potential of $250 million if more contractors are convinced that Tunnel-Boring Machines (TBM) are more suitable than conventional techniques. The worldwide civil tunnelling market has the potential to double each year in the next 5 to 15 years. Growth has been identified in the energy and mineral resources sectors of the economies of many nations and a significant volume of machine tunnelling studies and trials are presently underway for the extraction of coal, uranium , heavy oil or oil sand fuels, metallic and non-metallic industrial minerals and base metal or rare earth ores. Further tunnel projects for regional transportation, waterpower, irrigation , high density urban transportation, storm water sewers and water supply purposes are continually being implemented with new concepts like military security facilities and underground storage schemes being considered.Lo vat Tunnel Equipment of Rexdale, Ontario, the only Canadian manufacturer of TBMs was incorporated in 1973 to manufacture so ft ground tunnel-boring machines to satisfy this growing market demand. Lovat has produced an average of 5 machines per annum during the period 1972 - 1982 and has established an international reputation for competitive costs, quality of construction, after-sales service, and reliability. As of June 1982 Lovat TBM's have been used to tunnel over 240 km in projects throughout the world."

Jan 1, 1984

By V. S. Gischig, G. Preisig

Hydraulic stimulation of deep reservoirs is an essential procedure for developing engineered/enhanced geothermal systems (EGS), but also in other Geo-energy contexts. The goal is enhancing permeability to such a degree that fluid flow rates within the reservoir are sufficiently high for an economically productive reservoir. Two fracture stimulation mechanisms are distinguished that may occur concurrently during the hydraulic treatment: 1) During hydro-fracturing (HF) new tensile fractures are propagated from the borehole by means of a fluid pressure overcoming the minimal principle stress d3 plus the tensile strength T0 of intact rock. In case of a pre-existing fracture oriented normal to d 3 , the fracture can be opened by exceeding d 3 only. Fluid injection is performed via small packed intervals for creating a stack of hydraulic fractures. 2) During hydro-shearing (HS), over-pressure induces slip along pre-existing fractures that are favourably oriented in the stress field for reactivation in shear. Such stimulation is usually performed in a large packed interval or in an open borehole. Which mechanism occurs predominantly during stimulation depends on the rock mass structure and in-situ stress field, but also on the orientation of discontinuities intersecting the open-hole section and thus being pressurized. Both mechanisms also differ in how they affect fracture permeability. While permeability gained by HS is mostly irreversible due to rearrangement of asperity contacts accompanied with shear dilation, permeability enhanced during HF reduces nearly reversible after pressurization unless proppant is used to ensure permanent apertures. In this contribution, we critically discuss the pros and cons of both mechanisms regarding efficiency of enhancing permeability and the associated hazard of induced earthquakes based on literature review and numerical modelling. We review literature that reports on how much permeability required for productive EGS reservoirs and how much permanent permeability can be gained by stimulation. We also compile information regarding the degree of seismicity induced during HFor HS-dominated stimulation procedures, together with conceptual studies that reveal characteristics of seismicity associated with the two mechanisms. Many observations and models indicate that HF may have a higher tendency of being aseismic, while felt seismic events are usually associated with HS. Further, we present a hydro-mechanically coupled fracture flow model that investigates, if and to what degree the stimulation strategy can be designed such that one of the two mechanisms is evoked and dominates over the other. It shows that HS may dominate in presence of larger persistent fractures nearly optimallyoriented in the stress field, even if HF is attempted in short packed intervals. The model further demonstrates that stress transfer during HS promotes the development of permeability across an anisotropic layer of the stimulated rock instead of a large volume. Hence, the study sheds light onto the feasibility of creating productive EGS reservoirs in crystalline rock at several kilometres depths.

Jan 1, 2015

By L. A. Jameson, J. Awmack, P. J. Lind

"Peñasquito is a polymetallic deposit containing gold, silver, lead, and zinc. The operation is currently the largest producer of gold in Mexico. Over the next few years, the process flowsheet will be expanded beyond the flotation of lead and zinc to include flotation of pyrite from zinc tails and subsequent leaching of the pyrite concentrate. This paper outlines mineralogical leach characterization that has been carried out to improve the understanding of the complex hosting of gold and silver minerals in the ore. Organic carbon that is present in the ore can have an impact on flotation and leaching. Mineralogical techniques used to characterize this deleterious component of the ore are introduced.INTRODUCTION Goldcorp’s Peñasquito operation is located in the Mexican state of Zacatecas, approximately 200 km from the city of Zacatecas as shown in Figure 1. Peñasquito has been in operation since 2009 and is currently Mexico’s largest gold mine. Mining is carried out by open-pit methods, with oxide ore proceeding to a heap leach facility and sulfide ore treated in the sulfide processing plant.The processing capacity of the sulfide plant is 130,000 tonnes of ore per day and in 2016 production amounted to 450,000 ounces of gold, 17.6 million ounces of silver, 109 million lb of contained lead, and 263 million lb of contained zinc in lead and zinc concentrates. GEOLOGY The Peñasquito deposit is hosted in and adjacent to two breccia pipes; Peñasco and Breccia Azul. The two breccia pipes are branches of a larger intrusive-related complex, which is hosted in the sedimentary Caracol formation as illustrated in Figure 2. The regional geology is dominated by Mesozoic sedimentary rocks which comprise a thick series of marine sediments deposited during the Jurassic and Cretaceous periods. A 2 km thick sequence of carbonaceous and calcareous siltstones and interbedded sandstones is underlain by a 1.5 to 2 km thick limestone sequence (Goldcorp Inc., 2015)."

Jan 1, 2017

The cost benefits of controlling dilution of extracted ore have been very well understood by miners and mining professionals for many years. However, as we strive towards more mechanization, the dilution factor has been compromised in order to fit ?equipment? that is better suited to provide improved safety and productivity. Alternately, the drilling and ground support is accomplished by handheld drilling. In 2007, a short study, commissioned by CAMIRO (Canadian Mining Industry Research Organization) on the safety of hand held drilling vs. mechanized drilling, concluded that the risk of injury with handheld drills was seven times greater than with mechanized drills. Armed with this data, MEDATech Engineering proposed to the CAMIRO group to fund development of a ?MICRO Bolter?.

May 1, 2009

By R. S. Boorman, L. J. Surges

"Ore reserves at Brunswick Mining and Smelting totalled 101(106) tonnes grading 97 grams tonne-1 silver at the end of 1981. Silver is recovered as a byproduct in the copper, lead and bulk concentrates and is lost to the zinc concentrate and plant tailings. Recovery of silver for the year 1981 was 58,5%. The loss of potential revenue is in excess of Cdn $50(106) year-1 at current silver prices and milling rates.Silver is known to occur in solid solution in galena and as tetrshedrite. Evidence indicating the identity and significance of a third silverbearing mineral assemblage is reviewed and the distribution of silver losses is detailed. Characteristics of each the carrier which may be responsible for observed distribution, including size, surface quality, liberation and composition are considered, and the third carrier is shown to have possible implications for improved silver recovery by other Canadian producers as well as by Brunswick Mining.Silver tetrahedrite tailings distributed tailings and losses occur as coarse, free and as very fine unliberated galena in losses of the third carrier are between the zinc concentrate and are concentrated in the finest size fractions. Process alternatives for enhanced silver recovery by physical and chemical means are reviewed."

Jan 1, 1983

By P. L. Claessens, S. Belisle, C. Bowen

"Use of zinc shot feed is a well-established procedure among North American electro-galvanizers. This form of zinc is easy to handle and relatively inexpensive when compared with zinc oxide. This paper reports results on the kinetics of zinc shot dissolution in traditional pure zinc solutions and in electrolytes used for the plating of nickel/zinc alloys. Despite the cementation of minor amounts of nickel in the latter solution, acceptable dissolution rates of the zinc shot can be achieved through proper adjustment of the solution velocity. Under these conditions, the nickel shell produced by cementation is continuously abraded, exposing the underlying zinc.IntroductionThe use of insoluble, noble metal-containing anodes rather than soluble zinc anodes for the operation of high current density electro-galvanizing lines has gained almost universal acceptance. Two major reasons for this trend are:• improved control of the process by virtue of constant inter-electrode distance; and• increased productivity because the operation of the lines does not require the relatively frequent interruptions for replacement of consumed anodes .The results of the principal anode and cathode reactions are, respectively, depletion of the zinc content of the electrolyte and the increase on its acidity;"

Jan 1, 1991

By G. D. Just

"Extensive mechanization of underground mining operations, improvements in blasting technology and the development of simulation models for systems evaluation has now made it feasible to optimize rock fragmentation and materials handling operations. Methods of achieving these objectives are described in this paper, with particular emphasis on the need to obtain precise field data measurements. Techniques are illustrated with reference to the sub-level open stoping system of mine production. IntroductionThe primary objective to be achieved in any mining system is to deliver a specified grade of ore to the mineral processing plant at a planned delivery rate and at the minimum total mining cost. Design and management of such a system is complicated by the large number of unit operations and the often unknown inter- relationships between the different unit processes. This particularly applies in underground mines, where planning restrictions and unit costs are much greater than in comparable tonnage sur face mining operations. These difficulties can often be resolved by the application of judgment based on extensive experience, but the costly trial -and-error methods required for new technology discourage innovation.Most modern medium- and large-scale mines are now extensively mechanized. Consequently, the performance of each unit operation by individual items of equipment should be predictable for a given set of conditions. An essential prerequisite is that quantitative performance data are available from field measurements. Such information can then be used to optimize the design and management of the complete mining system to achieve the minimum tot al mining cost. One of the most significant factors influencing all unit costs is the degree of rock fragmentation. The importance of this variable is indicated by the fact that opt imization of rock fragmentation implies minimization of tot al mining system costs."

Jan 1, 1980

By A. E. Boudreau

It has long been recognized that platinum-group-element (PGE) deposits in layered intrusions preferentially occur in intrusions that crystallized from high-Mg parent magmas. Recent studies suggest that evaluation of any given intrusion for economic PGE potential should also include assessment of the PGE, sulfur and chlorine concentrations in the cumulates and potential parent liquids. PGE: Magmas that contain relatively abundant Pt and Pd are the best candidates for forming economic deposits. Although analyses of coeval sills and dikes are the best indicators of primary magmatic PGE concentrations, analysis of the cumulates themselves is also valuable. For example, within the Stillwater complex, background PGE values in cumulates from the ultramafic sections of the complex contain, on average, several 10s of ppb Pt and Pd. Background concentrations of this order are suggestive that the magma was not depleted in the PGE. Sulfur: Conventional petrogenetic models for the formation of PGE deposits in layered intrusions require the PGE to have been concentrated during a magmatic sulfide-saturation event. In contrast, some hydro thermal models suggest that sulfur and the PGE were mobilized from footwall cumulates by upward-migrating, high-temperature hydrothermal fluids. Both models suggest that significant PGE deposits are likely to occur at and below the level where stratigraphic increases in whole rock sulfur concentrations occur. Chlorine: In both the Stillwater and Bushveld complexes the cumulate sequences below the major PGE-bearing zones contain anomalous Cl-rich apatite. The chlorapatite component of apatite in these rocks may exceed 40% and, in the Stillwater complex, typically exceeds 90%. It is stressed that pristine igneous mineral analysis and not whole rock data be used, as whole rock Cl concentrations may be affected by very localized (grain boundary), low-temperature alteration. Intrusions that crystallized from high-Mg, high-Cl magmas appear to have the best potential to host significant PGE deposits.

Jan 1, 1995

By Fridrik J. Kristjansson, Stephen R. Hicock

"Three varieties of till are recognized in the Beardmore-Geraldton area: local lodgement till, nonlocal carbonate till, and local supraglacial till. The local lodgement till unit is examined in detail for the first time in this paper. It is the best potential overburden exploration medium for gold and other metals because its particles were locally-derived and deposited subglacially, probably within a few kilometres downglacier (southwestward) from their sources, and have not been diluted by distantly-derived glacialdebris. Both local tills are richer in gold and other metals, relative to nonlocal carbonate till. Local lodgement till rests on bedrock and was encountered frequently at or near the surface in thin drift/bedrock terrain (a widespread terrain type within the west half of the study area), and commonly at the base of boreholes in thick till terrain.INTRODUCTIONDrift prospecting in areas of glaciated terrain has been well documented (in a variety of journal publications and symposium volumes; e.g . Strobel and Faure 1987; MacDonald and Mills 1988) and has proven valuable especially where overburden thicknesses hinder traditional exploration techniques. Drift prospecting techniques may well prove valuable in the Beardmore Geraldton area. This applies especially to the Wildgoose Lake Turkey Lake area where a thick and laterally extensive sheet of nonlocal carbonate till has impeded conventional mineral exploration programs (Fig. I; note the lack of gold occurrences around Wildgoose Lake).Till in .particular has been cited as the best prospecting medium among the various types of glacial sediment (e.g. Shilts 1984). Three end member till varieties are recognized in the study area: (I) local lodgement till which rests directly on bedrock; (2) non local carbonate till; and (3) local supraglacial till which occurs predominatly within, or just downglacier of, upland areas where it commonly mantles the other till varieties. Previous authors have documented how the non local carbonate till hinders gold exploration (Geddes and Kristjansson 1986; Karrow and Geddes 1987; Kristjansson 1986; Hicock 1986, 1987a, b, 1988; Kristjansson and Thorieifson 1987; Thorleifson and Kristjansson 1987, 1988a, b) and why the local supraglacial till may be a good unit for prospecting (Hicock 1986). One detailed surficial geology map sheet of the area has been published (Kristjansson et al., 1988) and others are in preparation. Closs and Sado (1981) reported on the geochemistry of soils and glacial sediments in the west half of the study area. This paper documents the local lodgement till unit and demonstrates why it is the best overburden unit to use for drift prospecting."

Jan 1, 1989

By Jose R. Hernandez-Aguilar

"This paper revisits data from previous studies (Hernandez-Aguilar, 2010, 2011) to better understand the link between metallurgical performance and bubble size (Db) in the collection (pulp) zone of full-scale flotation systems. To obtain conclusive evidence exclusively related to the collection zone, the experiments were designed in those studies to control both the bubble generation method and the influence of the froth zone on the overall metallurgical performance in industrial and pilot-scale flotation columns. The results showed that generating small (1 mm) bubbles had a significantly higher beneficial effect on the recovery of coarse (> 75 µm) particles compared to the effect on fine (< 16 µm) particles. It was observed that, under certain practical conditions, the recovery of liberated coarse particles was close to zero, but could be recovered almost completely by reducing bubble size. The evidence revealed an apparent inconsistency of the so-called “k–PSb” model: at constant froth recovery, increasing Sb did not always result in higher recovery, as the model predicts. Overall, the evidence showed that it was not the Sb but the bubble size that proved to be a more reliable link to metallurgical performance. Only under highly suboptimal bubble size conditions (Db = 3 mm) did the froth zone seem to play a role, possibly reflecting an effect of pulp-zone bubble size on froth stability. However, for the most part, both the bubble generation method and the froth zone played inconsequential roles. An empirical model that better describes the kinetics of particle collection is proposed.INTRODUCTIONStudies showing the link between metallurgical performance and the interactions of bubbles and particles in the collection (pulp) zone of industrial flotation systems are scarce. A common belief among a number of mineral processing practitioners considers that “small” bubbles are favourable to recover “small” particles and that, conversely, “larger” bubbles are more efficient at floating “coarse” particles. However, perceptions like this are often substantiated by anecdotal evidence rather than by rigorous data analysis. What is the optimum bubble size for a particular case, how operating conditions can be adjusted to control a target bubble size, and whether the bubble size needs to be changed in the first place to optimize the operation of a flotation plant are questions that usually remain without solid answers.The studies reported by Hernandez-Aguilar (2010, 2011) were, in part, performed to test the effect of bubble size on flotation response and, thus, help address some of the above questions. The focus of the studies was to optimize the metallurgical grade-recovery performance of the Cu-Mo separation plant at Teck’s Highland Valley Copper mine (HVC). The outcome was compelling and significantly valuable: consolidated production data showed that in 2008 – the year when the recommendations from the studies started to be implemented – the Mo plant recovery was 89%, and gradually increased to 92% and 94% in 2009 and 2010, respectively, along with an increase in Mo concentrate grade. (Note: these production figures were not included in the publications quoted above; however, they were shown during an oral presentation at the 43rd Annual Meeting of the Canadian Mineral Processors in 2011.)"

Jan 1, 2016

By Matt Manson

?? Current Exploration and Assessment ?? Overview of Potential Development ?? Infrastructure ?? Opportunities and Challenges ?? Renard? 1-10 kimberlite pipes and ?Lynx-Hibou? kimberlite dyke system within ?Foxtrot? property ?? 50/50 Joint Venture between Ashton (a subsidiary of Stornoway) and SOQUEM ?? Discovered 2001-2003 ?? Québec is routinely assessed as one of the top mining jurisdictions in the world ?? Agnico-Eagle Mines Ltd. Is Stornoway?s largest shareholder and a leading mine developer in Québec

May 1, 2008

By Ross G. Bertinshaw

"The Line Creek Mine of Crows Nest Resources started mining coal in the fall of 1981. There are seven mineable seams with thicknesses ranging from 1.5 to 13 metres and with dips varying from 0 degrees to 60 degrees. This, together with internal partings and the very friable nature of the coal, creates a number of mining problems.The coal is divided into zones depending on the dip of the seam. Each zone requires a different mining technique to ensure optimum recovery and low dilution while still keeping fines to a minimum.Line Creek employs a combination of hydraulic front shovels and backhoes to mine its coal without blasting or use of dozers. This has been very successful in reducing the proportion of fine coal hauled to the plant, thus improving quality control and reducing costs in coal processing.There have been a number of other benefits from the use of excavators instead of more conventional methods. These include better selectivity, good cleanup, reduction in traffic at the face and lower cost.IntroductionThe Line Creek Mine is situated approximately 25 km north of Sparwood in southeastern British Columbia (Fig. I). Preproduction stripping began in J98J with the first coal shipments made in 1982. In 1983 the mine produced 2.1 million tonnes of raw coal.Similar to other East Kootenay coals, the seams at Line Creek are characterized by their friability, producing a large proportion of fine coal during mining. In an attempt to reduce these fines Crows Nest Resources has instituted the use of hydraulic excavators to mine and load the coal.Hydraulic excavators offer other substantial advantages over front-end loaders and dozers, which has been the conventional system in other mines in the area."

Jan 1, 1985

By S. Banisi, J. Marois, A. R. Laplante

"This paper compares the behaviour of gold and ore in the grinding circuit of Hemlo Mines Ltd. Particular attention is given to grinding kinetics, classification behaviour, and liberation. For grinding kinetics, laboratory grinding of gold flakes and silica, 840 µm to 1200 µm in size (14/20 mesh), was also performed to provide a standard for comparison and to study in a controlled environment the mechanisms of breakage, folding , smearing and impacting.Grinding kinetics were characterized at laboratory scale with breakage and selection functions. The breakage function showed that 75% of gold disappearing from the 840 µm to 1200 µm class reported to the 600 µm to 840 µm; this figure is much higher than for silica (46%) or most other minerals, and implies that comparatively fewer fine fragments are produced from the breakage of gold flakes, on account of gold&apos;s malleability. The selection function of silica was four times that of gold. At plant scale, the ratio of the selection function of ore and gold increased from 6 for at 50 urn to JOO pm to 20 at 500 um to 1000µm.Observation of original flakes and their fragments with the scanning electron microscope showed that the main mechanism of ""grinding"" from the 840 µm to 1200 µm to the 600 µm to 840 µm class was folding rather than actual breakage. This was confirmed by a measure of individual flake weight. The postulated breakage cycle is that relatively globular flakes become increasingly serrated through grinding; they can then regain their original shape through folding and reflattening into cylindrical and spherical shapes, as the majority does; however, some fragments will at this point undergo actual breakage. Photograhic evidence is presented to support the proposed mechanisms.Smearing of gold unto silica was observed when silica was ground after a gold, and embedding of silica into gold flakes when gold was ground after a silica. Both mechanisms occur whenever gold and harder minerals are jointly ground, and result in ""unliberation"" of gold. It is postulated that smearing of gold onto other minerals plays an important role in explaining how gravity recovery can increase over-all gold metallurgy, especially when used ahead of flotation.Classification of gold in the primary hydro cyclones takes place at a much finer cut-size than ore, 20 µm vs 57 µm. This and the slower grinding kinetics result in high gold circulating loads in the primary loop, 6700%, and a gold content in the primary cyclone underflow (PCUF) is twenty-four times that of the ore. The gold size distribution for primary cyclone overflow is much finer than that of the ore, although they are essentially similar in the PCUF.Liberation, or more accurately ""gravity recoverability"", was assessed with a 7.5 cm (3 in.) Knelson concentrator. It varied between the thirties for the primary mill discharge and two cyclone overflows, to highs of 89% and 92% for the PCUF and secondary mill discharge."

Jan 1, 1991

By Paul Toor

The operation of SAG mills is variable over time due to their continually changing liner shape, mass and subsequent load motion. However, this tends to be poorly accommodated in liner design and mill control, with only limited compensation made for this influence, usually in the first few weeks after a new liner is installed. With ever-increasing ore competency, increasing energy costs and decreasing ore grades, simplified design and operational approaches that compromise the achievable mill efficiency are no longer adequate. This paper presents a methodology that has been developed to measure and account for the changes in mill performance as the liner wears. This involves monitoring all liner profiles ? in other words the three-dimensional liner shape - over the life of the liner, then conducting controlled surveys at different stages of the liner wear life, and correlating the mill performance to the liner profiles. The measured liner mass is modelled to provide an ongoing meaningful load mass measure that excludes the liner mass.

Jan 1, 2012

By Gurupraveen Ramanathan

Slot raises are relief holes within a stope in longhole stoping methods, designed to provide a free face that facilitates the expansion of the blasted rock during blasting, ultimately achieving the desired fragmentation. Various methods are employed to produce these slot raises, like conventional drop raise drilling, raisebore & V30 drilling. However, slot drilling is generally characterized by high costs and limitations in precision, resulting in unplanned ore losses and dilution. This paper introduces a novel alternative to slot drilling referred to as the "paste slot", designed specifically for paste backfill operations in underground mining. This new method emphasizes considerations in cured paste strength, paste wall removal, and stope dimensions and employs modified drop raises or dumped rings to optimize blast gas effectiveness and material flow. The paste slot method eliminates the need for reamers and reduces the total slot drill meters an average from 650m to only 300m for narrow stopes (3-4m wide). This significantly reduces the stope cycle time, leading to substantial cost savings and increased productivity. This new method was successfully implemented at the underground mines in Canada and Australia, resulting in a 20% reduction in stope cycle time and cost savings of 53,000 USD per slot compared to the conventional slot. This paper discusses the design and execution strategy of the paste slot method in underground paste backfill operations. It highlights the advantages of the method, shares operational insights gained during implementation, and showcases its potential applicability to other mines across Canada and globally.

Oct 1, 2024

By Finley A. Campbell

"Nickel-copper sulphide deposits associated with basic rocks in the Quill Greek area and the White River area in the Yukon Territory have been studied and compared from the view-point of their general geology, structural geology, and the mineralogy of the ores. The relative amounts of the major constituents, magnesium, iron and calcium, and the minor constituents, nickel, cobalt and chromium have been determined spectrographically for two cross sections of the basic rocks at Quill Creek and one at White River. These data, along with petrologic and field evidence, were used to determine the sill and dyke-like character and nature of the basic intrusions. Loss on ignition is employed as a measure of the degree of serpentinization. The distribution determined shows that the serpentinization does not appear to have greatly influenced the inferred original distribution and lithophile associations of magnesium and nickel. The cobalt content may have been altered.The nickel content of the serpentinized peridotites ranges from an average of 0.36 per cent in one section to an average of 0.24 per cent in each of the other two sections studied. The cobalt averages 0.0038 per cent in the samples from the two Quill Creek sections and averages 0.0042 per cent at White River. These results have been compared with other available data.The sulphide ores are later than both the peridotite and gabbroic rocks and may be co-magmatic with them. There is no evidence in these areas to support an origin by lateral secretion; on the contrary, the alteration associated with the ores, the mineralogy and spatial relationship to basic and ultrabasic rocks, indicate the ores are derived from a basic magma."

Jan 1, 1960

By N. K. Jaber

The "Pidgeon Process" for the extraction of magnesium from dolomite ore utilizing ferrosilicon as the reducing agent has been studied extensively by active metallurgists such Mr L,M, Pidgeon the father of this process, Most of the work sited so far has focused on heating the (FeSi/MgO,CaO) briquette mix under vacuum in stainless steel retorts by external fuel hydrocarbon heating, In this work Electrical Induction Heating was employed as the heating method whereby the briquette mix was placed in a steel crucible around which an Induction Heating copper coil was wound and placed inside in a stainless steel vacuum tank, It was observed that by virtue of the fast Induction Heating method utilized in the silicothermic extraction process higher reduction temperatures were reached in shorter periods of time due to fast heat transport into the ore charge mix, This facilitated shorter metal reduction times as compared to the conventional fuel heating methods.

Jan 1, 2006

By Farzad Khodabakhshi, Adrian P. Gerlich

"Multi-pass friction stir processing (FSP) was performed to fabricate a new Al-Mg-Graphene nanocomposite. Microstructural developments and distribution of graphene were studied by using electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM) analysis. In the stirred zone (SZ), grain structure was refined down to about 2 µm attributing to the operative dynamic restoration mechanisms and the locking effect of graphene phase. As a result, the yield strength of Al-Mg alloy was improved more than two times due to incorporation of graphene nano-sheets. Also, the indentation hardness resistance of nanocomposite was increased up to ~60%.INTRODUCTION Aluminum-matrix nanocomposites have garnered significant in recent years due to their superior performance and potential advantages for several industrial applications including the automotive and aerospace sectors. Among various reinforcing nano-materials, carbon-based structures featuring sp2 or sp3 hybridization bonds have been found to offer considerably improved physical and mechanical properties. Such carbon allotropes form at micro- and nano-scales including; graphite, carbon nano-tube (CNT), nano-fiber, and graphene. The potential of two-dimensional (2D) carbon materials was introduced in 2004, with the development of graphene as an alternate 2D allotropic form of the carbon structure with a honey-comb lattice at the atomic-scale. It has been shown that it is currently among the strongest materials ever tested with an intrinsic tensile strength of 130 GPa and Young’s modulus of 1000 GPa, and also offers unique thermal and electrical properties.To fabricate metal-matrix nanocomposites reinforced by graphene nano-sheets with typical metallurgical processing techniques, some attempts have been reported in the literature for various solid-state techniques including; hot rolling, mechanical alloying, and friction stir processing (FSP) of pre-cast plates or surface dispersed graphene oxides. The main challenge in those methods was to facilitate the considerable high temperature and pressure for attaining a uniform dispersion of the nano-sheets during the consolidation process. In most cases, significant difficulties have been reported in obtaining a uniform dispersion of graphene within the metal matrix. Among various techniques for production of metal-matrix nanocomposites, FSP has attracted significant attention as a method of surface modification since it was first reported by Mishra et al. In this process, a non-consumable rotating tool is plunged into the surface of material for the aim of microstructure modification. Extreme material plasticity is induced without melting as a result of friction between the tool and workpiece. Frictional heating and severe plastic deformation induced by the FSP process enables metal matrix nanocomposite fabrication by softening the base material and mechanical stirring to disperse the reinforcing nano-materials into the matrix."

Jan 1, 2017

By Shahram Tafazoli

ABSTRACT: This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

Oct 1, 2009