Search Documents

By D. W. Heard

Electrospark Deposition (ESD) is a low heat-input, high energy density, micro-welding process. The short pulse duration and high-pulse frequency, in combination with the small amount of material transferred during each pulse, results in the evolution of extremely rapid cooling rates, believed to approach 105-106 °C/s [1]. This rapid solidification event results in the refinement of the microstructure to the nanostructured or amorphous level [2, 3]. Figure 1 displays the resultant microstructure of an Al-17%Si alloy deposited by the ESD process. Furthermore, it was determined that the microstructure of the deposit remained unchanged after subsequent layers were welded onto the presented layer. Freeforming of materials is a rapid prototyping process in which the deposited feedstock is built-up to the desired geometry in a near-net shape manner. Figure 2 displays the automated set-up employed produce three dimensional freeformed objects via multiple deposition trials of the ESD process. The automated XYZ table is equipped with CNC software to transform CAD renderings into three dimensional tool paths. Figure 3 displays an Al-12Si freeformed gear (2" diameter, 12 teeth) produced by the ESD process, prior to removal from the substrate. An SEM analysis of the freeformed component showed that the microstructure did not coarsen during the deposition of subsequent layers during the freeforming process, as depicted in Figure 4, resulting in the production of a bulk nanostructured component. This paper represents a summary of the capabilities of ESD to fabricate advanced materials possessing refined microstructure. In particular, results on the microstructural evolution obtainable for various wear-related systems will be presented. In addition, the feasibility of using the ESD process to freeform three-dimensional objects via multiple deposition passes will be presented and accompanied by a characterization of the properties of the freeformed component. [1] R. N. Johnson, "ElectroSpark Deposition: Principles and Applications," in Society of Vacuum Coaters, 2002, pp. 87-92. [2] J. Milligan, D. W. Heard, and M. Brochu, "Formation of nanostructured weldments in the Al-Si system using electrospark welding," Applied Surface Science, vol. 256, pp. 4009-4016. [3] S. Cadney and M. Brochu, "Formation of amorphous Zr41.2Ti13.8NilOCul2.5Be22.5 coatings via the ElectroSpark Deposition process," Intermetallics, vol. 16, pp. 518-523, 2008.

Jan 1, 2010

By Kristine Haug

Although most in situ operations in Alberta do not encounter significant problems during resource extraction, there have been a few documented occurrences of oil or steam releases as a result of compromised caprock seals. The objective of the Oil Sands Caprock Integrity Project (OSCRIP) is to characterize the units above and below bitumen zones to determine which geological factors affect the quality of the caprock seal. In addition, geomechanical properties and stress measurements of the bitumen reservoir and overlying units will be examined to provide a better picture of the containment conditions in which in situ operations occur. The information from this study will aid regulatory staff and industry in determining the zone-specific geological and geomechanical factors that could affect the design, operation, and feasibility of in situ recovery projects. The OSCRIP study area (Townships 87 to 99 and Ranges 1 to 13, West 4th Meridian) encompasses the surface mineable area, the northeast extent of the Wabiskaw-McMurray bitumen deposit and the Clearwater Formation, as well as a wide band of the Devonian salt-dissolution zone. Regional geological mapping of the Cretaceous strata focuses on the spatial extent and thickness of the caprock seal. Mapping of the underlying Devonian strata is targeted at better understanding the potential effects of salt dissolution and collapse of overlying strata on the integrity of the caprock seal. Examination of LiDAR (Light Detection And Ranging) bare earth DEM in the study area has revealed localized depressions that may represent sinkholes rooted in subsurface collapse features in Devonian carbonate and evaporite strata. Mapping the location and understanding the timing of salt dissolution-related features and deformation in the Devonian strata will help address questions about the possible effect that geological structures, such as sinkholes, have on the integrity of the caprock, as well as the potential for localized variations in the stress regime of the bitumen zone and overlying units. The stress regime in units above 350 m is such that any induced fractures are believed to be horizontal, and therefore, there would appear to be no mechanisms that would allow these fractures to reach the surface. However, recent incidents have shown that vertical pathways can occur, linking the subsurface to the surface. The final phase of the project will evaluate the changes that may occur in the stress regime under thermal operating conditions in the study area.

Jun 1, 2012

By Scott D. Long

"Abstract-Grass roots exploration has an emphasis on good precision at low (sub-economic) concentrations of an element, in order to identify "anomalies" which may lead to drilling targets. Although it is wise to have well-defined quality controls in place during early stage sampling, the control procedures at this stage tend to be rudimentary. When a deposit warrants detailed delineation, the need for accurate geological characterization and assaying of ore-grade rock must be supported by appropriate quality control procedures.As a project returns more promising results, and the likelihood of the project warranting a prefeasibility study increases, it is time to tighten quality assurance requirements and quality control protocols. Delays in instituting adequate quality control and verification procedures may lead to costly remedial actions that can also delay completion of the prefeasibility or feasibility study. Sometimes, as a project matures, the quality control and quality assurance aspects fail to keep pace with the changing nature of the work: an increasing emphasis on precise and accurate assaying of oregrade rock.A resource model is like a house of cards. The foundation of the house is the geological observations, the sampling methods and the geological interpretations performed upon those samples. Upon the sampling, which includes all the sub-sampling steps of sample preparation, rest the assay results. The quality of the assays can be no better than the quality of the sampling. Good assaying technique will preserve all biases and imprecisions introduced during sampling and sample preparation; it cannot remove them. If the sub-samples and/or assays are bad and must be redone, all the succeeding levels of the house of cards must also be rebuilt, or at least patched up.From geological observations, a geological interpretation is built, the quality of which is critical to the construction of an acceptable resource model. Geological elements are difficult to assess, and are not discussed here; they are dependent upon the expertise of the geologists involved. Geological knowledge contributes essential quality control elements to resource/reserve determinations (Sinclair and Postolski, 1999; Postolski and Sinclair, 1999).This paper consists of five sections: (1) overview of quality control protocols, (2) maintaining quality control of databases, (3) quality control of drill sampling, (4) optimizing crushing and grinding requirements, and (5) quality control of assay data acquisition."

Jan 1, 1998

By E. E. Mueser

As Mr. Lundberg has already ably covered the theory of various methods of electrical prospecting, I shall confine my remarks to a consideration of the features which must obtain in an electrical prospecting method in order that it may be useful from a practical standpoint. These remarks I shall make with particular reference to the Elbof method. The successful application of all these methods rests, in the first place, upon the possibility of correlating theory, or empirically established facts, with the field data. Their practical usefulness, however, requires that the technique of making the field observations, and the procedure itself, be such that the method may be applied to large areas, under normal average conditions. The method, therefore, should not involve excessive preliminary labour costs to prepare the ground for actual prospecting work, nor should the prospecting work itself be so slow that its cost, when applied to extensive areas, becomes prohibitive. Moreover, it should be possible to apply the method even under difficult terrain conditions, such as rough topography and dense vegetation. It may be said of most of the methods referred to in the preceding paper, that, while they are interesting and theoretically sound, they fail to meet such practical requirements as I have outlined.

Jan 1, 1926

By Ana Adé

The use of gold compounds in homogeneous catalysed organic reactions has been undervalued for many years due to the preconceived opinion that gold is an expensive and extremely chemically inert metal. However, recent reports have changed this assessment and gold salts in small amounts are known to display high catalytic activity.[1] Thus, it has been reported recently that anhydrous AuCl3 catalyses the formation of C-C and C-O bonds (usually mediated by hydrochloric and other protonic and Lewis acids).[2] Some examples include Michael type additions, selective cross cycloisomerisation/dimerisation of propargyl or allenyl ketones, benzannulation between o-alkynylbenzaldehides and alkynes or cyclisation of alkenyl furans. It is noteworthy that some of these reactions[2a] can be also catalysed by silver salts but with much lower yields. The 1,3-dipolar cycloaddition of nitrones to alkenes is a powerful synthetic method that has found numerous applications in the synthesis of a variety of carbon frameworks.[3] Several laboratories have focused on the development of Lewis acidic reagents to modulate the selectivity of the reaction.[4] Despite the extensive study performed, there are not many examples in which a metallic complex catalyses the dipolar cycloaddition. Most of these reactions require the presence of a metallic complex and nitrone in a 1:1 molar ratio. Recently, we have carried out stoichiometric reactions of the N-benzil-C(2-pyridil)nitrone, 1, with different dipolarophiles in the presence of zinc and silver compounds.[5] Apart from an increase of the reaction rate and the selective formation of one of the possible isomers, we have shown the formation of zinc and silver-nitrone complexes during the reaction, which behave as the intermediates in the cycloaddition process. As suggested by the results obtained with silver complexes, we decided to test gold derivatives (in the oxidation states of I and III). Interestingly, we have found that they can be used not only as stoichiometric reagents but they can also mediate these cycloadditions in catalytic amounts (5 to 10 mol % respect to the nitrone). Here we present the results on the 1,3-dipolar cycloaddition reaction of the N-benzil-C(2-pyridil)nitrone (2-PyBN), 1, and methylacrilate, 2, (Eq. 1) catalysed by gold(III) derivatives.

Oct 1, 2003

By Eric D. Monrad

Supply chain simulation modeling is taking on a more prominent role in mining project planning and decision making. Transportation costs for the supply chain can form a significant component of the overall cost to provide product to the end customer. In recent years, computing power has increased, simulation software has advanced, and simulation specialists have become even better equipped to provide sophisticated analysis and recommendations. This has led to a virtuous cycle of owners expecting and supporting data-driven analytics, which drives further advancement. This paper discusses developments in supply chain planning and two case studies from recent simulation modeling analyses.

May 1, 2013

By T. Kalliomäki, A. T. Aji, M. Lundström, J. Aromaa

The settling properties of anode slime in copper electrorefining have crucial effect on copper cathode quality. Anode slime settling is affected by electrolyte composition and temperature, electrolyte circulation, and the sizes and density of the slime particles and agglomerates. Typically, the industrial copper electrolytes contain 40–60 g/dm3 Cu2+, 130–220 g/dm3 H2SO4, 0.04–25 g/dm3 Ni2+, 0.005–30 g/dm3 As, and have operating temperature of 55–70°C. In optimal electrorefining process, the settling rate of anode slime is sufficiently high to avoid the risk of getting the slime entrapped in copper cathodes. In this research the settling properties of copper electrorefining bottom slimes, mainly consisting of Cu, Ni, Ag, Se, Pb, As, Bi, Sb and Ba compounds, were studied by settling rate tests. The tests were conducted in water and synthetic electrolytes with known viscosities and densities. In addition, the effect of agglomeration was taken into account – it was observed that breaking the agglomerates which existed in the as-received slimes decreased the particle sizes on average 56–73%, which decreased the settling rate. The results of this study provide detailed information of anode slime settling and thus clarify the conditions causing cathode contamination risks in copper electrorefining. INTRODUCTION Settling rates of Cu-ER anode slimes affect the purity of cathode copper and faster settling rate decreases the contamination risk (Davenport et al., 2002; Shi & Ye, 2013). The settling rates are affected by the properties of anode slime particles (Wills & Napier-Munn, 2011; Aaltonen, 2014; Kiviluoma, Aaltonen, Aromaa, Lundström & Forsén, 2016) as well as viscosity and density of the electrolyte (Davenport, King, Schlesinger, Biswas, & Robinson, 2002; Shi & Ye, 2013). Thus, it is crucial to find out how the viscosity and density affect the settling rates. Small spherical particles with diameter below approximately 50 µm obey Stokes’ law (Equation 1) (Wills & Napier-Munn, 2011). v = gd 2 (ρS – ρF) (18η) -1 (1) where v is terminal velocity (m/s), g acceleration due to gravity (m/s2), d diameter of particle (m), ρS density of particle (kg/m3), ρF density of fluid (kg/m3), and η dynamic viscosity (Pa∙s). The approximate effects of kinematic viscosity (ν = η / ρS), density (ρS) and particle sizes on settling rates defined for small anode slime particles based on Stokes’ law are presented in Figure 1. However, Stokes’ law does not take into account other than spherical shapes, and it is only applicable for small particles. Consequently, the real settling rates of the particles are lower than these (Wills & Napier-Munn, 2011). Moreover, some of the anode slime particles are larger than 50 µm (Aaltonen, 2014).

Jan 1, 2019

By Lassi Klemettinen, Ari Jokilaakso, Dmitry Sukhomlinov, Pekka Taskinen

The solubilities and distributions of molybdenum and iridium in iron silicate slag and copper-iron mattes were studied using an equilibration-quenching technique and subsequent direct phase composition analyses by EPMA (Electron Probe X-ray Microanalysis) and LA-ICP-MS (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry). The equilibrations were carried out on a wide matte grade interval, ranging from 55 wt-% Cu to 75 wt-% Cu, in pSO2 = 0.1 atm at 1300°C. The results in equilibrium with a solid iridium-molybdenum alloy indicated an iridium solubility of 150–500 ppmw in the sulphide matte, depending on the matte grade, and a molybdenum solubility of 100–600 ppmw. Iridium was distributing predominantly in the sulphide matte with the distribution coefficient of 10+3 - +4 but molybdenum deported predominantly in the slag with Lm/s(Mo) = 0.02–0.1. The effects of alumina and lime additions in the smelting slag were also examined. INTRODUCTION Iridium is a highly siderophile element (HSE), which means that it is incompatible with the sulphide forming elements and possesses a small solubility in mattes, such as copper- and nickel-iron sulphide melts. Molybdenum behaves only modestly in that way (Walker & Li, 2008; Righter et al., 2017). They both are known to be trace elements accompanying copper and nickel sulphide ores. No solubility data, however, are available for them in copper-rich sulphide mattes. Geochemical data on the behaviour of Ir and Mo deal mostly with low-iron silicate systems, e.g. basaltic melts, and high-sulphur sulphide solutions and mattes (Ertel et al., 2008; Fonseca et al., 2007). They also indicate that Ir and Mo dissolve in silicate melts primarily as oxides and not as electrically neutral metal species. Most geological data of iridium focus on high-sulphur systems of the monosulphide composition and typically Fe-Ni mattes where copper is a trace element (Fleet et al., 1996; Sattari et al., 2002). Direct solubility measurements for mattes and iron-lean silicates have also been made using pure Ir or an Ir alloy as the saturation phase (Borisov & Palme, 2000; O’Neill & Eggins, 2002; Makovicky & Karup-Møller, 1999; Ertel et al., 2008; Mungall & Brenan, 2014). A recent summary about the solubilities of HSE’s in iron- and sulphur free silicates is available in Laurenz (2012). The thermodynamics of molybdenum partitioning between oxides and Fe-S-O melts was studied by Mengason et al. (2011). Their results indicate strong accumulation in the iron-rich sulphide in reducing conditions (pO2 = 10-9.6 atm in Ni-NiO equilibrium at 1050°C). Molybdenum dissolves in iron-lean silicate melts as MoO3 species in oxygen pressures above the Fe-FeO equilibrium and as MoO2 in more reducing conditions (Farges et al., 2006; Righter et al., 2017).

Jan 1, 2019

By C. Sui, J. E. Nesset, M. Li, J. Y. Kim, S. L. Chryssoulis

"A plant study of zinc rougher flotation at Brunswick Mining was conducted using lime, soda ash and a combination of both as the pH modifiers in order to establish the effects on sphalerite and pyrite kinetics and mineral selectivity. The plant sampling and analysis was augmented by surface analysis using TOF-LIMS, SEM and XPS as well as fundamental precipitation and surface-charge studies in the sphalerite Ca/C03/S04 system.The results revealed the important role of carbonate ions in cleaning the sphalerite surface for effective activation by CuS04 to occur, and the beneficial role of combined soda ash and lime in increasing pyrite and galena depression.1.0 IntroductionThe studies reported in this paper were initiated as part of an investigation into the causes of a particularly pronounced seasonal deterioration in metallurgical performance at the Brunswick Mining concentrator during the summer of 1995. The concentrator treats a complex base metal ore having a typical feed composition of 9.0% Zn, 3.5% Pb, 0.4% Cu and 100g/t Ag at a current throughput of 9,000 TPD, although at the time of the problem in 1995, the average production rate was closer to 10,500 TPD. Zinc, lead, copper and bulk (zinc-lead) concentrates are produced with overall metal recoveries of 86% zinc, 63% lead, 60% copper and 60% silver; results which are typical of the lower recoveries associated with fine-grained, highly complex VMS and SEDEX type deposits. The main economic minerals of interest are an iron-containing (7% Fe) sphalerite, galena and chalcopyrite with the main diluent (about 60% wt) being pyrite.Figure 1 shows a simplified flowsheet of the Brunswick milling circuit while the seasonal decrease in summer metallurgy in 1995 is illustrated in Figure 2. Of significance is the rapid drop in copper and lead recovery in June while there is an apparent delay until late August-September before the zinc deterioration reaches its lowest point. A more typical seasonal effect within the experience of the authors is the reverse of the Brunswick situation, namely an improvement in summer performance thought to be associated with improved differential flotation kinetics during warmer weather leading to better mineral selectivity. The historical Brunswick experience was particularly severe during the summer of 1995 with estimated incremental losses of $10 Million for this period. The potential of the very significant economic benefits to be gained from understanding and hopefully improving the annual drop in performance led to an investigation involving the minesite metallurgical group, the Noranda Technology Centre (NTC) as well as researchers in Professor Jim Finch's group at McGill and the surface analytical services and interpretive skills of AMTEL."

Jan 1, 1998

By Diego L. Romero, Joy P. Romero

"IntroductionMinerals may be classed broadly as ferromagnetic (magnetite for example), as paramagnetic (attracts to regions of magnetic field convergence) and as diamagnetic (attracts to regions of magnetic field divergence). High-intensity separators are not necessary to separate ferromagnetic minerals from other classes. Rather, low-intensity units that generate fields below 5000 gauss are adequate for this purpose. However, paramagnetic minerals, such as ilmenite, with high magnetic ""attractability"" require fields of up to 10 000 gauss; those with low attractability may require even higher fields. Table 1 shows approximate ranges of field intensities necessary to separate ferromagnetic and paramagnetic minerals from minerals of lower attractability, along with the force with which they are attracted relative to iron in a standardized magnetic field.Uniform magnetic fields, not useful for separators, are generated between flat parallel surfaces; non-uniform fields, useful for separators, arise when at least one of the surfaces is of irregular shape. The diagrams below show how magnetic lines of force align relative to north and south poles.If a particle is placed in a uniform field, it feels no displacing force unless the particle distorts the applied field assymmetrically. This is not the case in non-uniform fields which are required for magnetic separators.Magnetic fields can be generated by permanent magnets (low intensity), by electromagnets (medium and high intensity) and even by superconducting coils (100 000 gauss fields and higher), although the latter are not as yet useful in production environments .The magnetic force of attraction per unit of mass, that acts on a paramagnetic mineral such as hematite, increases in proportion to the strength of the field . Unfortunately, the highest fields attainable with electromagnets is of the order of 20 000 gauss. Fortunately, the gradient of the fie ld (that is, the degree of convergence of magnetic lines of force) is important, because the attractive force per unit mass is proportional to it also . This can be stated:"

Jan 1, 1989

By C. A. Godden, T. N. Atkinson

Metallographic techniques developed from studies of corrosion films and electroplated coatings on aluminum alloys, are discussed. These methods, the result of work at the Naval Research Establishment, give extremely flat fields at the interface despite the large difference in hardness, in cases where electrolytic polishing could not be used. Techniques to overcome the similarity in refractive index of immersion oil, aluminum ox1d~, and mounting plastic are also considered, as are methods for improving visual and photographic contrast in areas of interest. A device for marking specimens is also de-scribed. ELE•CTROLYTIC polishing is inapplicable in the study of surface films on aluminum, whether corrosion films or electrodeposits. Mechanical procedures must there-fore be followed. Sample flatness and edge retention are of paramount importance. Special measures are required in the study of oxide films, because of the close proximity of the refractive indices of aluminum oxide, mounting plastic, and immersion oil.

Jan 1, 1962

By E. Nurminen

Thermal transport properties of copper flash smelting flue dust have been investigated. Such values of the dust are needed to correctly model the process and to optimize its heat recovery performance. Dust accretions on heat recovery boiler walls may have a significant influence on the boilers heat transfer efficiency. Measurements of the thermal transport properties have been made for industrial flue dust and for pure sulphate components. The measurements have been conducted at temperatures up to 400 °C and the effect of porosity on these properties has also been investigated. The results indicate that the flue dust and the sulphate components are effective thermal insulators and the dust build-up on the boiler walls is likely to greatly decrease the heat transfer efficiency of the boiler.

Jan 1, 2007

By Q. Shi, Q. Feng

"The influence mechanism of chlorite on the flotation of pyrrhotite was investigated through flotation tests, Zeta potential measurements, optical microscope photos, solution ion measurements and absorption measurements. It is observed that, the addition of chlorite influences the flotation of pyrrhotite seriously. The IEP (isoelectric point) of pyrrhotite and chlorite is 7.6 and 4.3 respectively, in the condition of slight alkalinity, both pyrrhotite and chlorite are negatively charged, and the hetero-aggregation will not occur. With the existence of oxygen in solution, the iron ions are dissolved from pyrrhotite surface because of the oxidation of pyrrhotite during pulp conditioning. The dissolved iron ions adsorb onto the surface of chlorite in the forms of iron hydroxyl and iron hydroxide, and the adsorption results in the opposite charge of chlorite surface. As a result, the hetero-aggregation between pyrrhotite and chlorite occurs. The adsorption of chlorite changes the surface property of pyrrhotite and restricts the adsorption of amyl xanthate onto pyrrhotite surface, and then decreases the flotability of pyrrhotite.INTRODUCTIONIn sulfide ores processing, magnesium silicate bearing gangue minerals often report to the concentrate causing downstream processing problems as well as increased smelting costs. Talc,chlorite and serpentine are gangue minerals commonly encountered in complex sulfide ores (Engel, Middlebrook, & Jameson, 1997; Pietrobon et al., 1997; Witney & Yan, 1997; Chen, Grano, Sobieraj, & Ralston, 1999a, 1999b; Bremmell, Fornasiero & Ralston, 2005; Senior & Thomas, 2005; Wang, Somasundaran, & Nagaraj, 2005; WieseHarris & Bradshaw, 2007). All of them are characterized with uniform crystal structures consisting of silicon-oxygen tetrahedron and magnesium-oxygen octahedron. The magnesium-oxygen octahedron layers are broken during the liberation of serpentine to expose the magnesium-oxygen bonds with strong ionicity and hydration, which results in natural hydrophilicity of serpentine. In water, the hydroxyl on serpentine surface ruptures and dissolves into the aqueous phase while the Mg2+ remains, resulting in surface positive charge (Tao, 2012). As serpentine has a positive potential at alkaline condition, it is therefore likely that it will attach through electrostatic attraction to the negatively charged mineral surface and reduce both the flotation rate and recovery of target minerals (Lu et al., 2011). For talc, characterized as good natural hydrophobicity, the liberation comes from the interlaminar fracture to remain molecular bonds on surface with weak hydration. Being naturally hydrophobic, talc easily reports to flotation concentrates, thus reducing concentrate grade (Shortridge, Harris, Bradshaw, & Koopal, 2000; Beattie, Huynh, Kaggwa, & Ralston, 2006). Meanwhile, both molecular bonds and magnesium-oxygen bonds are exposed on chlorite surface when liberation occurs, resulting in moderate natural hydrophobicity between serpentine and talc (Tao, 2012). And thus the mechanisms of influence of chlorite on sulfide ores are more difficult to study."

Jan 1, 2016

By George A. Guess

The making of contracts for the purchase of ores is a business which the metallurgist usually understands better than the miner. Companies in the custom ore business often employ an ore buyer who is aware of the class of ore which the smelter needs, and is thoroughly conversant with the business. The miner on the other hand makes ore contracts but seldom, and it is often only after a settlement has been made that he realizes the meaning of the terms of the contract under which he has sold his ores. He has expectations usually greatly in excess of the amount 'net proceeds' shown at the bottom of the settlement sheet. Seldom does the occasional shipper really know his contract. A somewhat similar parallel is to be found in insurance policies. We all have insurance policies; we never know the conditions contained in them until after the fire. The clauses in the policy are for the protection of the Insurance Company. An Insurance Company has no friends.

Jan 1, 1926

By R. Gordon, J. Palich, W. Qian

The EarthProbe DCIP system deploys tightly spaced electrodes connected to a centralized data acquisition system that enables arbitrary selection of current and potential electrodes through relays. Rapid data collection (approximately 1000 readings per hour) and advanced signal processing allow for efficient use of conventional and novel arrays and the removal of natural and cultural noise. What is unique about the system is its electrode and borehole cable design, which allows seamless integration of borehole and surface measurements. EarthProbe operates in four configurations - surface, borehole, borehole-to-borehole, and surface-to-borehole (a variant of the borehole-to-borehole configuration).

Jan 1, 2011

By Ron Jessulat

"IntroductionBrunswick Mining and Smelting Corp. Ltd. is a IO 500 tid base metal producer. Development is carried out by Jarvis Clark MJM-21 3-boom development jumbos, using Tamrock E400, 410 and 550 pneumatic drills. Typical drift size is 13 ft by 18 ft with a 12-ft advance per round. Blast holes are 1 ½ in. in diameter while reamed holes are 3 in. in diameter. AN/FO is the principal blasting agent, being loaded by C-I-L model60R intermediate loader. The detonators are NONELS and DETINELS. Sulphide dust explosions occur during blasting when dusts from certain minerals such as pyrite and pyrrhotite are ignited by name from the detonating shots. The result is a secondary unwanted explosion with a characteristic shock wave and name front that are very destructive to mine services such as ventilation ducting, electrical cable, and ventilation control doors.A typical reaction in the Brunswick orebody occurs according to the chemical formula:4FeS 2 + IIOs-2Fe2O3 + 8SO2 + 3458--(Enright , 1988)The hematite (FeO3) is deposited as a red dust in the blast area while the toxic sulphur dioxide gas (S00 contaminates the underground workings . The presence of S02 gas disrupts production until it is purged from the area by the mine ventilation system or dissipates slowly in those areas where the vent ducting has been melted by the name front or torn down by the shock wave.Sulphide dust explosions exact a high economic toll. Direct costs in damaged materials and wages are probably exceeded by the value of lost production and disruption to the mining cycle. In addition, the health and safety concerns associated with sulphide dust explosions cannot be ignored."

Jan 1, 1993

By T. Robson

"A multi-seam underground mining operation employing mechanized room-and-pillar methods provides 35 per cent of Smoky River's annual ROM coal production (2 million tonnes) from the Smoky River coal field. Surface mines provide the balance. Tectonic activity, which has resulted in deformed coal seams and a rugged relief to the area, has provided natural boundaries to discrete mining areas. Coal transportation to the central preparation plant incorporates a 3 km long underground conveying system. The company is committed to efficient resource recovery and a safe and healthy working environment. Introduction The Smoky River Coal operations (SRC) are centered in the Smoky River coal field located in west central Alberta, some 360 km west of Edmonton and 20 km from the Town of Grande Cache (Fig. 1). Combined mining operations produce 2 million tonnes per year run-of-mine coal from which 1.65 million tonnes of high quality, low volatile, coking coal are obtained. The underground mining operation, employing mechanized room-and-pillar methods, provides 35 per cent of SRC's annual ROM coal production (2 million tonnes). Surface mines provide the balance. Tectonic activity has resulted in deformed coal seams and a rugged relief in the area. This has provided natural boundaries to discrete mining areas. Background Exploration of the Smoky River coal field took place over four decades commencing in 1926. McIntyre Mines Limited (parent to Smoky River Coal Ltd.}, commenced development of the property in 1968 having secured a long-term contract for the delivery of coal to Japan. Production of underground coal at Smoky River commenced toward the end of 1969 and has been continuous on the property since that time. Originally, two underground mines were opened. Original planning envisaged the use of room-and-pillar techniques to develop blocks of coal for subsequent extraction by longwall retreat mining. Following initial development, two longwall units were established, the first in November 1970 in No. 5 Mine and the second in February 1971 in No. 2 Mine. Difficulties were experienced on both units, and production commitments could not be achieved. The longwalls were discontinued, and mechanized room-and-pillar was subsequently used for all underground mining."

Jan 1, 1985

By BARRY BANNATYNE

About 90 per cent of Manitoba's industrial minerals production is for structural materials. Most of these come from the Paleozoic rocks west of the Precarnbrian Shield, or from glacial deposits that are extensive throughout Manitoba. The major raw materials are sand and gravel, and carbonate rocks for crushed stone (and also dolomite for high-magnesia lime, high-calcium limestone for lime and Portland cement, and dolomitic limestone for Tyndall stone). Glacial lake clays are used both in cement and in lightweight aggregate. The Jurassic and Cretaceous strata exposed along or near the Manitoba Escarpment include siliceous, carbonaceous, kaolinitic and illitic shales, all of which are quarried by Red River Brick and Tile in the Pembina Mountain and Ste. Rose areas for use in a brick plant at Lockport. Non-swelling bentonite near the base of the Pembina Member of the Upper Cretaceous Vermilion River Formation is of value as an absorbent clay, and is the only commercial source in production in Canada. It has been quarried by Pembina Mountain Clays Limited since 1940. Gypsum occurs in the Jurassic Amaranth Formation and supplies much of the market for wallboard and Portland cement additive in the Prairie Provinces. Quarries are operated at Gypsumville by Domtar Construction Materials Limited, and north of Amaranth by Westroc Industries Limited. Silica sand from the Ordovician Winnipeg Formation is of glass-grade quality, and about 100,000 tonnes are produced annually by Steel Brothers Canada Limited on Black Island . It is used as a glass sand, as foundry sand, for sand blasting, and as a filter-bed sand .

Jan 1, 1984

By Alex Luyima, Michael Moats

"In the present work, the oxidation of manganous and chloride ions on a mixed metal oxide (MMO) anode from a 40 ºC electrolyte containing 160 g/L sulfuric acid (H2SO4) with various concentrations of Mn2+ and Cl- was studied using cyclic voltammetry. These results indicated that Mn2+ concentration does not affect Cl2 evolution on a non-MnO2 coated MMO anode. However once MnO2 deposits on the MMO anode, Cl2 evolution is inhibited. The effects of manganous concentration and chloride concentration on the amount of MnO2 deposited in one hour were also evaluated. Cl- concentration did not affect the amount of MnO2 generated. Increasing Mn2+ concentration resulted in an increase in the amount of MnO2 deposited.INTRODUCTIONThe electrolytic recovery of zinc (Zn) is a well-known process and is estimated to produce approximately nine million tons of Zn per year worldwide (Recendiz, Nava, Lartundo-Rojas, Almaguer, & Gonzaleza, 2009). The Zn produced by this process is of high purity and has a wide range of applications, such as galvanizing (car body parts, pipes, metal wires, etc.), sacrificial anodes in offshore industries, casting alloys, alloying of brass, primary and secondary battery industries, etc.The electrochemical production of Zn employs aluminum cathodes and lead-silver anodes (Pb- Ag) (Recendiz et al., 2009). The Zn containing mineral (ZnS) is usually associated with other elements such as Mn, Mg, Ca, Cd, Cu, Cl, Fe, F, Co, Ni, Al, As, Sb, Si, Sn, Ge, Hg etc. (Nijjer, 2000). After processing of ZnS concentrates, the electrolyte obtained still contains residual metallic and non-metal impurities. Some of these impurities can impact the corrosion rate of Pb-Ag anodes."

Jan 1, 2016

By K. Soucek, J. Ptácek, A. Hastíková, R. Kukutsch, P. Konícek, P. Waclawik

"Cable bolts are used frequently as a secondary support system (with steel arch support) in difficult stress-strain conditions of deep coal mines. The load transfer mechanism of cable bolts depends on several factors, such as the strength, deformation and geometric properties of the bolts, resin and the surrounding rock mass so-called cable-resin-rock system (CRR system). The bonding length and bolt/borehole diameter ratio strongly influence the final bearing capacity of the CRR system.The study presents the behaviour of CRR system during a pull-out test which is usually used in the carboniferous rock mass in the Czech part of the Upper Silesian Coal Basin. A series of 28 pull out tests were performed on 3-m-long cable bolts, with various combinations of borehole diameters and bonding lengths, to understand this behaviour. Boreholes were drilled into a solid rock mass consisting of fine-grained sandstone to guarantee similar conditions during the pull-out tests. Video inspection and measurement of borehole diameters were performed to determine their quality and real diameters. Three characteristics were observed from pull-out test results: ultimate pull-out load; displacement of the end of bolt and system stiffness. Numerical modelling by FEM (Finite Element Method) was used to determine the stiffness of the CRR system for variable bolt/borehole ratios and bonding lengths each under constant load. A linear elasto-plastic model and a mohr-coulomb model were used for cable and resin-rock respectively. The results of the experiment may contribute significantly to improving of the methodology of cable bolts installation as well as the design of used cable bolts."

Jan 1, 2015