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By H. L. Gibson, T. N. Setterfield, J. J. Watkins, R. W. Hodder

"The McDougall-Despina fault set in the Noranda district of northwestern Quebec defines the eastern margin of the Despina cauldron, nested within the district-scale Noranda cauldron. The faults are stratabound in that they displace stratigraphy of the cauldron fill, but do not off-set the cauldron cover. The faults are occupied by dikes that acted as eruptive centers to volcanic members of the cauldron-filling sequence. Measurable displacement across the McDougall-Despina fault set is greater than 750 m, and coincident with post-cauldron volcanism. Feeder dikes cross-cut each other and are typically depleted in Na2O and CaO, and enriched in MgO, K2O, Fe2O3and MnO relative to fresh flows. Economic and subeconomic massive sulfide deposits occur adjacent to the McDougall-Despina fault set at different levels over a stratigraphic thickness of 3000 m. These include the Corbet deposit, the subeconomic D-68 Zone deposits, and the subeconomic stringer zones of South Rusty Hill and Bedford Hill. Numerous copper occurrences and abundant hydrothermal alteration occur in and immediately adjacent to the fault set.The McDougall, Despina, and adjacent, parallel, ancillary faults define a synvolcanic fault set which controlled the location of magmatism, hydrothermal alteration and mineral deposition during the early evolution of the Noranda cauldron. Significant sulfide mineral deposition commonly occurred in proximity to the intersection of the McDougall-Despina fault set with northeast-trending synvolcanic faults. Recognition of synvolcanic faults is therefore a major objective of exploration programs for volcanic-associated massive sulfide deposits."

Jan 1, 1995

By C. H. Bertoni

"The Superior Province of the Canadian Shield is the largest gold producing area within Archean greenstone rocks in the world, with total production of over 140 million ounces of gold. One hundred and fifty-five mines have individually produced more than 8,000 ounces, although only a relatively limited number of deposits (33) produced more than one million ounces of gold. The output from these 33 deposits accounts, however, for 85% of total gold production. The majority of grades (68%) ranges between 0.10 and 0.30 ounce per ton, and there is no linear relationship between grade and tonnage.Development of new gold mines reflects the history of gold prices. However, the response to the latest increase in gold prices was not as marked. It is concluded that gold deposits are becoming increasingly more difficult to find and new exploration techniques are urgently required.IntroductionWith most of its production coming out of the Superior Province, the Canadian Shield is the largest producer of gold from Archean greenstone rock s in the world. In total gold production, the Superior Province is surpassed only by the paleo-placers of Witwatersrand and the placers of the USSR (Anhaeusser, 1976). There has been no attempt so far to compile the historical production of the Province as a whole in a single document. The aim of this work is to fill this gap, not only for the convenience of having a complete list of gold producers, but, more importantly, as a basis on which to study the tonnage and grade characteristics of these deposits."

Jan 1, 1983

By L. S. Jen

Canadian copper, nickel, zinc, lead and molybdenum mines are characterized by the mining of ores from which more than one metal is recovered. During the 1980s, approximately 15% of the gold, 25% of the zinc, 30% of the copper, 55% of the molybdenum, 80% of the silver and 90% of the lead produced from Canadian mines were produced as co-products and by-products of base metal mining operations. This trend is not expected to change significantly in the near future. The presence of co-products and by-products affects the level of production and the level of revenue from base metal mines in several ways: (I) in general, production of one base metal cannot be expanded or cut back without affecting the amount of production of another metal;(2) the commercial success of certain base metal mining operations depends on the substantial bonus revenues from co-products and by-products; (3) the quality and economic viability of many ore deposits are significantly improved by the presence of co-products and by-products; and (4) while coproduction is critical to the survival of some mines, bonus revenue from by-products can also be life saving to others during economic downturns. For these reasons, deposits with significant co-product or by-product values are likely to continue to be significant targets for exploration and for acquisition.

Jan 1, 1992

By Gonzalo Mato, Colin Godwin, G. Ditson

"The mid-Cretaceous Seagull batholith intruded Mississippian sedimentary and volcanic rocks and Jurassic(?) granitic and ultramafic rocks within the Omineca Crystalline Belt in the Yuk on Territory near the British Columbia boundary. Leucoerotic fluorine- and boron-rich granites of the batholith exhibit many textural variations from aplite to pegmatite, but are dominated by a coarse-grained seriate unit and a fine-grained porphyritic unit.Four distinctive tin vein occurrences within and near the batholith are described, the most interesting of which is the MC showing of quartz-calcite-chlorite-cassiterite veins in intensely fractured zones of sedimentary and volcanic rocks. Three other showings occur within the batholith:J) the EC showing of quartz-fluorite-cassiterite-sulphide veins with prominent muscovite-illite alteration;2) the DU showing of quartz-hematite-fluorite-sulphide- sulphide-cassiterite with considerable manganese staining and sericitic alteration; and3) the VAL showing of quartz-tourmaline-cassiterite-fluorite-arsenopyrite veins with little associated alteration.Most cassiterite occurrences are within easterly-trending, vertical structures and all occurrences are thought to represent parts of a single system. These mineralogical and physical variations are apparently related to the distance from the upper contact of the batholith.For the Seagull batholith, Rb-Sr isotopic data give a 100±1.4 Ma isochron age that is concordant with the K-Ar model age from biotite of 101±4 Ma. Initial Sr isotopic ratios for the batholith are high at 0.712, indicating an old, sialic crustal source for this pluton. This initial ratio is similar to values for granitic rocks associated with tungsten deposits in the Yukon Territory. The high initial ratio for Sr, the high Si02 content, the high s/I index, the presence of normative corundum. leucogranitic composition and associated lithophile-tungsten mineralization demonstrate that the Seagull batholith is probably an S-type granitic body. This factor is significant to regional exploration jar tin and tungsten in the Canadian Cordillera."

Jan 1, 1983

By Morgan Schauerte, Laura Raimondi, Mariel Palomeque

Executives in the mining industry are facing dramatically changing market expectations on reporting and transparency regarding the environmental and social impacts of projects, supply chains and products. Companies increasingly need to disclose the governance procedures they have in place to ensure communities, investors, employees, and Indigenous partners are effectively managing social and environmental risks. These disclosure requirements begin during exploration and carry through to all stages along the project life cycle. This type of environmental, social and governance (ESG) disclosure is referred to as ESG performance by the investment community. ESG is not a new concept, and it builds on and is intertwined with many concepts such as corporate sustainability, corporate social responsibility, eco-efficiency, triple bottom line thinking, life cycle management and many others. This paper will explore how mining companies can develop a credible ESG governance approach and strategy that will reduce risk, open opportunities, and create value. This paper will summarise ESG trends and drivers, discuss the economics and investors’ perspective towards ESG, and outline leading ESG standards and guidelines of interest to investors, regulators, communities and other stakeholders. Linkage of ESG to global sustainability efforts such the United Nations Sustainable Development Goals and Global Compact will also be addressed.

Jan 1, 2023

By R. Prioul, J. Kear, D. Chuprakov, A. P. Bunger

"Hydraulic fracture (HF) growth through naturally fractured rocks challenges the development of accurate predictive HF models. The authors present laboratory experiments differentiating behaviours associated with orthogonal and oblique intersections between HFs and natural fractures (NFs). HFs were created in sandstone and crystalline (gabbro) rock specimens, impinging orthogonally or obliquely on an unbonded machined frictional interface. Ultrasound monitoring was used to observe the rate of propagation through the interface. A contrast was observed between direct and offset crossing for orthogonal and oblique intersection, respectively. The stresses required to promote crossing depended on the intersection angle between HFs and NFs.RÉSUMÉ La propagation des fractures hydrauliques (FH) dans les roches naturellement fracturées pose un défi pour le développement de modèles prédictifs. Nous présentons des essais en laboratoire qui différencient les comportements associés aux intersections orthogonales et obliques entre les FH et les fractures naturelles. Des FH ont été créées dans des spécimens de grès et de roches cristallines (gabbro), heurtés de manière orthogonale ou oblique sur une interface machinée, non liée, de frottement. Un suivi par ultrasons a servi à observer le taux de propagation à travers l’interface. Un contraste a été observé entre un croisement direct et un croisement indirect des intersections respectivement orthogonales et obliques. Les contraintes requises pour promouvoir le croisement variaient selon l’angle d’intersection entre les FH et les fractures naturelles."

Jan 1, 2016

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 Afshin Sadri, Wai Lai Ying, Brycklin Wilson, Zoe Coull

"Although there have been great steps forward to integrate corrosion engineering into operations, there is still an underlying tendency for maintenance tasks to be performed in a reactive manner. This is especially true when strategies focus on lagging indicators such as visual inspections, RCA (root-cause analysis), and FMECA (failure mode, effects and criticality analysis). This trend to “reactive maintenance” can be avoided by utilizing more inspection and monitoring methods to identify leading indicators of failures. Prevention is generally less costly than repairs; moreover, when paired with appropriate monitoring techniques, intervention of corrosion protection can be more effectively timed and based on more accurate data. Hatch asset reliability studies show nearly 80% of defects are introduced through operations and maintenance. Therefore, proactive corrosion management can provide the necessary feedback to optimize operations and maintenance strategies preventing costly corrosion losses. Understanding corrosion risks gives a clear picture of the benefits of a proactive approach to asset performance. Monitoring techniques (Non-Destructive Testing, field testing, sampling, etc.) by nature are a more effective means of improving maintenance efforts and preventing corrosion losses than other methods (RCA, FMECA). This paper will outline the importance of proactive corrosion management and demonstrate its benefits through industry examples.INTRODUCTION Over the past few decades, with the growth of technology and awareness of sustainable development many studies have shown the benefits of a proactive approach to maintenance strategies. However, in practice there is still an underlying tendency for maintenance tasks to be performed in a “reactive manner”. This is especially true when strategies focus on lagging indicators such as visual inspections, RCA (root-cause analysis), and FMECA (failure mode, effects and criticality analysis). This trend to “reactive maintenance” can be avoided by utilizing more inspection and monitoring methods to identify defects and leading indicators to failures."

Jan 1, 2017

By J. S. DeLury

The last few years have been eventful ones for Manitoba in connection with mineral development. Perhaps the past year has been the most important of all. It is therefore a suitable time to review the mining situation in the Province. In order to obtain, in the following paper, a proper set ting from which to discuss the trend of recent developments, a brief review of the story of mining will first be given. This will include a summary of a few of the outstanding facts regarding prospecting, discovery, and operations in the several known metalliferous areas of the Province. Following this will come a more detailed description of activities during the past year or two. Special attention will then be paid to the outstanding enterprises, such a~ those associated with the names of Flin Flon, Sherritt-Gordon, and Central Manitoba, names which have been attracting the attention of the mining world to Manitoba. And last of all will be presented a brief summary of mineral production, which, so far, has largely been credited to non-metallics. HISTORICAL To aid a proper comprehension of the recent trend in mining, it is well not to lose sight of the history of development in the different metalliferous areas in Manitoba. This Province seems throughout to have been more or less dependent on mining interest excited by discoveries in the neighbouring province of Ontario. The first interest came as an effect of the Lake of the Woods mining boom, when small adjacent parts of Manitoba were prospected. Several discoveries were made, but no mining industry resulted.

Jan 1, 1929

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The major importance of liners in grinding is their role in providing an appropriate trajectory for the charge. Since it is not possible to study the charge movement by direct observation in operating industrial mills, this task is accomplished by physical (laboratory), and/or, mathematical (software) methods. Because of the high cost and a longer time required for a physical analysis, mathematical simulations have become more common. Simulation of the effect of liner shape on the charge movement has provided a means to select a proper design based on the operational objectives and conditions. Furthermore, the liner shape changes due to wear and impact during operation, which will influence the charge trajectory. This adds more of an incentive to use simulation. These changes in liner could be predicted through liner profile measurements during operation and/or simulation. In this research, an inhouse developed DEM software called KMPCDEM © was used to simulate the charge movement in industrial plant SAG mills. A geometrical method of implementing the shell liners on SAG mills at the Sarcheshmeh (9.75×4.87 m) and the Gole-E-Ghohar (9×2.05 m) operations facilitated the software simulation. Point by point implementation of the measurements of liner profiles of these mills enabled the study to trend the change in the charge movement as the liners wear. Comparison of the simulation to a laboratory mill (1 m diameter) showed that the difference between the measured and predicted charge impact point, shoulder angle and toe angle were 6, 4 and 3°, respectively.INTRODUCTIONComminution is the most energy intensive operation constituting the major portion of operating and capital costs of a mineral processing plant. In the last decade, a vast number of research was aimed at studying various aspects of grinding with the aim of performance improvements (Davis, 1919; Mishra & Rajamani, 1990; kalala, Breetzke, & Moys, 2008). Mill liners transfer the input power to the charge and play a significant role in affecting the motion of the charge (Mclvor, 1983; Mishra & Rajamani, 1990; Radziszewski, 1997; Van Nierop, Glover, Hinde, & Moys, 2001; kalala et al., 2008). Lifters are usually used with mill liners to extend their life and to enhance the grinding and impact breakage efficiency. Mill lifters are used to raise the grinding media and ore to transfer the energy from the mill to the load (Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010)."

Jan 1, 2016

By Ray Collier

MINING TODAY l EXTENSIVE AND EXPENSIVE PERMITTING PROCESSES WITH UNKNOWN RESULTS l GENERAL AND IMPASSIONED RESISTANCE TO RESOURCE BASED INDUSTRY l SOPHISTICATED, ORGANISED, AND WELL FUNDED OPPOSITION l MOST LOCAL GOVERNMENT DOESN?T WANT MINING TODAY?S TALK l FOUR SPECIFIC OPERATIONS ON WHICH OUR EXPERIENCE IS BASED ? SECHELT ? CADMAN ? GRANVILLE ISLAND ? LEHIGH CEMENT DELTA PLANT l OUR APPROACH TO COMMUNITY RELATIONS

May 1, 2002

By Rocky (Yaokun) Wu

Rock burst is one of the biggest challenges to ground control in the mining industry. With increasing mining depth and mining scale, there are more and more industry requirements on yielding rock support. Since 2008, Jennmar has been conducting large scale research and development works to develop a technically reliable and cost effective yielding rock bolt. This paper introduces a new yielding rock support - Yield-Lok bolt. The bolt is characterized by the designed yielding ability to produce 150 ~ 250 mm of deflection at 8 ~ 10 metric tons (Mt) loads for every 16.4kJ energy input. Its performance characteristics are consistent through multiple and varying amplitude of impacts. In this paper, the design criteria of the bolt and the principle of performance are described, the dynamic testing results are discussed; and the features and application of the bolt are presented.

Oct 1, 2010

By Mehmet F. Taner

"Abstract - The East Sullivan Stock (ESS) is a small, composite felsic alkaline pluton of presumed late Archean age in the Val d’Or mining district. Three main facies have been distinguished: monzonite sensu stricto, porphyritic monzonite, and green trachytic porphyry. This monzonitic group of rocks is of relatively homogeneous composition with high abundances of Na2O, K2O, Ba, Sr, Rb, Zr, Mo and LREE. The alkaline ESS is distinguished from other igneous units in the Val d’Or mining district, such as the Bourlamaque Batholith, by relatively high concentrations of Ba, Sr, Rb, Mo, Cu and Au. The ESS hosts many base (Cu, Mo) and precious (Au) metal occurrences, including: (1) porphyry style Cu-Au-Mo disseminated sulfide deposits, (2) Cu-Au deposits in volcanic rocks near the ESS contact, and (3) pyritic gold mineralization in east-west trending shear zones. The ESS is well defined by concentrical zoning on the aeromagnetic vertical gradient color map, and displays four linear trends, which are assumed to be structural lineaments, at 035°-055°, 320°-300°, eastwest, and north-south. The main mineral occurrences related to the stock display a preferred spatial association with the east-west linear magnetic trends.The ESS is preferentially located along a major structure and was emplaced late in the evolution of the Abitibi subprovince like other felsic alkaline plutons. This stock is similar to late-tectonic mineralized felsic alkaline intrusions of the Kirkland Lake and Larder Lake mining districts in Ontario, and to the Allard stock in the U.S.A. which is associated with gold and base metal mineralization. Similarities also exist with younger alkaline plutons associated with Cu-Mo-Au porphyry deposits in the Canadian Cordillera, which formed in tensional tectonic environments. The felsic alkaline magma may have formed by partial melting of deeply buried supracrustal rocks, concomitant with the development of deep fractures such as the Cadillac Fault. In such an environment, hydrothermal solutions carrying remobilized metals from deep supracrustal rocks may have deposited gold and base metals in structural traps. Plutons similar to the ESS should be good targets for mineral exploration. Résumé - Le Stock de East Sullivan (SES) est une intrusion composite alcaline d’âge tardiarchéen, situé dans le camp minier de Val d’Or. Trois principaux faciès ont été identifiés: une monzonite sensu stricto, une monzonite porphyrique et un porphyre trachytique vert. Les données chimiques montrent que ce groupe des roches monzonitiques est relativement homogène en composition avec des concentrations élevées de Na2O, K2O, Ba, Sr, Rb, Zr, Mo et ETRL, définissant une suite alcaline typique. Cet alkalin stock peut être facilement distingué des autres unités géologiques de la région de Val d’Or, tel le batholite de Bourlamaque, par une concentration élevée de Ba, Sr, Rb, Mo, Cu et d’Au. Le SES contient plusieurs importants prospects de métal précieux (Au) et de métaux de base (Cu, Mo), incluant: (1) une minéralisation disséminée de type porphyre Cu-Mo-Au, (2) une minéralisation de Cu-Au dans les roches volcaniques encaissantes hôtesses près du contact et (3) une minéralisation d’or pyritique dans une zone de cisaillement de direction est-nordest. Le SES est bien défini sur la carte aéromagnétique en couleurs du gradient vertical par des zonages concentriques, où quatre linéaments structuraux ont été reconnus: 035°-55°, 320°-300°, est-ouest, et nord-sud. Les principales zones minéralisées spatialement associées au stock sont généralement situées soit près des linéaments magnétiques est-ouest, soit le long de ceux-ci.Le SES semble s’être mis en place le long d’une structure majeure, développée tardivement dans l’évolution de la Sous-province abitibienne, comme les autres plutons alcalins felsiques. Ce stock est similaire à la suite tardi-tectonique d’intrusions alcalines minéralisées des camps miniers de Kirkland Lake et de Larder Lake en Ontario, ou"

Jan 1, 1996

By Larry A. Morris

The environmental impacts of industrial activities have become very serious concerns of the public over the past few decades. Not surprisingly, governments have responded with legislation and regulations to force industry to operate in a more environmentally responsible manner and, more recently, have prompted industry to initiate voluntary measures in response to specific environmental issues. The concept of Product Stewardship has evolved as a system or vehicle for the industrial sector to demonstrate an active concern about the environmental impact of their products, services and processes.

Jan 1, 1996

By Larry A. Morris

The environmental impacts of industrial activities have become very serious concerns of the public over the past few decades. Not surprisingly, governments have responded with legislation and regulations to force industry to operate in a more environmentally responsible manner and, more recently, have prompted industry to initiate voluntary measures in response to specific environmental issues. The concept of Product Stewardship has evolved as a system or vehicle for the industrial sector to demonstrate an active concern about the environmental impact of their products, services and processes.

Jan 1, 1996

By Vincent Doyon

For several years, the GDD SSW EM Probe is being used in nickel?s mines in Canada and Brazil to define ore limits, reduce dilution and predict nickel grades. It is used with success to test most if not all percussion blast holes at all Falconbridge Mines in Sudbury and Raglan and all Inco?s Thompson mines. However, after testing the SSW Probe in other metal mines, we realized that EM conductivity does not define ore limits by testing blast holes for copper, zinc or gold. For non-conductive ores, no instrumentation is yet available on the market to reduce dilution, by outlining quickly and inexpensively the real shape of an orebody. To that effect, Instrumentation GDD Inc has developed a new revolutionary photonic probe that will make the reduction of dilution possible by probing blast holes. Once surveyed with the probe, a computer draws graphs of the ore grade as a function of depth for each blast hole. A contribution by Canada Economic Development made possible the development of this new technology. Canmet and Soredem also cautioned this technology developed by Instrumentation GDD Inc. This new photonic probe will allow: 1) to better understand the shape of the orebody 2) to raise the grade of the ore fed to the mill 3) a more complete extraction of the ore 4) to raise the competitiveness of mines

Oct 1, 2004

By A. Dave Mackintosh

The Current demand for potash has pushed world prices to record levels and allowed Saskatchewan producers to operate at maximum capacity. Several years of strong demand has resulted in a permitting rush not seen since the 1960?s. Even though Saskatchewan has a huge potash resource, mining and processing constraints will limit the areas of economic development. Introduction In 1969 M. E. Holter prepared a report ?The Middle Devonian Prairie Evaporite of Saskatchewan?, published by the then Dept. of Mineral Resources. Holter?s report has remained the bible of geologists working in potash ever since. It is astounding that a report written before there was really much potash mining history in the province, is as valid today as when it was first published. This paper re-iterates much of Holter?s report and adds a little mining experience to essentially confirm the importance of his work.

May 1, 2008

By David R. Lentz

At True Hill in southwestern New Brunswick, low-grade porphyry-style Bi-8n-Mo greisen mineralization is associated with the cupola of an epizonal granite porphyry (granite) that also exhibits three episodes of brecciation. The first episode of brecciation is an in situ, 8 m to 10 m wide transitional zone of net-veined to coarse-grained "blocky" endogranitic mesobreccia that is chloritized and greisenized and hosts weak disseminated minerali.zation. In a zone closer to the host rockgranite contact, angular fine- to coarse-grained endogranitic mesobreccia with greisenized matrix is superimposed on the earlier transitional breccia. The latest episode is fault-controlled and consists of quartz- and chalcedony-hosted sub-angular to rounded fine-grained "pebble" mesobreccias that crosscut and brecciate the other breccia types, as well as the adjacent altered metasedimentary country rocks. The first two episodes of brecciation are magmatic-hydrothermal in origin related to hydrofracturing of the granite carapace and are accompanied by greisenization and mineralization, whereas the post-mineralization, silica-hosted, "pebble" mesobreccias related to hydromagmatic, low-temperature fluid circulation and/or boiling along faults near the contact. These magrnatichydrothermal and hydromagrnatic mesobreccias are similar to those associated with W-Mo-Bi porphyry-greisen mineralization at the Mount Pleasant deposit.

Jan 1, 1994

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 G. R. C. Pacheco, D. M. Fonseca, R. Neuböck, G. E. Gonçalves, W. Moulin-Silva

Degradation by sulfur gases is an important lining wear mechanism in the copper industry. SO2/SO3 gases infiltrate into the pores of the basic refractory bricks, combine with their raw materials through expansive reactions and significantly modify the bricks’ structure. This study presents a comparison of the corrosion resistance against sulfur attack of different magnesia-based refractories using a simple, low-cost and quantitative method. Recipes containing sintered MgO grains showed lower resistance to corrosion by sulfur oxides compared to basic grades containing fused grains. Chromium corundum grades were used as a reference and showed very good resistance to this corrosion mechanism under the test conditions. The novel test provided relevant results that agree with what is commonly observed during operation and in previous post-mortem studies. This tool could be very useful in selecting refractory grades for the copper industry and predicting their performance. INTRODUCTION Oxidation of matte sulfides during copper production leads to the formation of sulfur oxides, which infiltrate into the pores of the refractory lining and react with the basic oxides below 1000°C to form magnesium and calcium sulfates. This reaction is accompanied by an expressive volume increase, consequent densification of the refractory microstructure and weakening of the brick bond (Malfliet et al., 2013). Thus, corrosion by SO2/SO3 is an important wear mechanism in the non-ferrous industry and the resistance to this compound should be considered when defining refractories for this application. Previous studies on this matter include expensive and complex testing methods involving pressurized SO2 gas cylinders in order to investigate the corrosion resistance of MgO-containing materials by sulfur oxides (Gerle & Podwórny et al., 2016; Fotoyi & Eric, 2011; Fotoyi, 2009; Podwórny & Piotrowski et al., 2008). The current study was based on a test developed by Pacheco & Fonseca (2018) to assess alkali infiltration and aims to provide an evaluation method of the corrosion resistance of refractories by SO2/SO3 in a simple and quantitative manner. This novel test is useful to compare the corrosion resistance of different refractory recipes and properly select the grades that should be employed in the non-ferrous industry. A case study is provided to illustrate the damage caused by sulfur oxides in refractory linings.

Jan 1, 2019