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By François Charette

High stress conditions in underground mines push the performance envelope of support systems to their limit. In weak rock masses these conditions lead to large deformation and breakdown of the rock material, while stress release events in hard rock mines can lead to sudden and usually violent rock and support failure. In typical support systems, a combination of different reinforcement and support mechanisms provide the required convergence control and retainment. These systems usually involve a multi-pass support installation. The advantages of a single pass support system are investigated and several bolting combinations are compared. Criteria for design are reviewed and new criteria are proposed to include cost and effectiveness in commonly used engineering approaches. Field observation and testing is used to illustrate the difference between the proposed approach and more conventional systems.

Nov 1, 2011

By O. Schnake, M. Isakson, C. A. Landolt

The paper presents the conceptual basis for the development of an Activity Based Costing system (ABC) for the analysis and estimation of process costs in mining and metallurgy. In particular, it discusses three major thrusts towards attaining increased efficiency in extraction and processing systems: (a) understanding the link between process and expenses, (b) identifying the chemical and physical factors that govern process costs and ( c) using process and cost models of the production systems. The authors have developed computer techniques to analyze data from conventional accounting and apply them to the development of process based ABC systems. The cost causing activities are linked to management units patterned after the organizational structure of the production system. All costs are associated with specific process functions such as charge preparation, smelting, refining, etc. The level of detail is determined by the quality of data available in conventional accounting systems. The system permits data analysis of historical cases and the projection of costs for new production schemes. Results can be presented in various levels of aggregation, following organizational and/or functional structures. The outputs of the system are tabular and graphical, typically following Pareto analysis concepts.

Jan 1, 2007

By D. A. MacFadyen, J. J. Brummer, C. C. Pegg

"The first record of a kimberlite found in Canada (1946) was the identification of thin dykes intersected while drilling for gold in Michaud Township, Ontario.Sampling of the Munro Esker (1964) in the Kirkland Lake area, Ontario, by the Geological Survey of Canada identified the occurrence of detrital grains of pyrope garnets along a length of 35 km of the 113 km tested. A search for the source of the garnets resulted in the identification (1968) of a narrow subsurface kimberlite dyke in the Upper Canada Mine. This discovery resulted in a staking rush. Unfortunately, subsequent work did not identify the source of the kimberlite indicator minerals.During 1978 the Ontario Geological Survey started a multi-discipline study of 29 townships (2560 krn2) in the Kirkland Lake area, to encourage exploration for gold, base metals, and kimberlites. Back-hoe sampling (1979 to 1982), where the overburden was thin, and reverse circulation drilling, in areas of thicker drift, yielded samples of the till. These were analyzed for several elements and a mineralogical identification of the heavy minerals was completed. Pyrope and chrome diopside grains were identified.Studies of the Pleistocene geology indicated only the most recent direction (167 degrees) of ice advance (Matheson) and the associated deposits, out of a possible three advances known to occur in the general region straddling the Ontario-Quebec boundary, is present in the immediate area of Kirkland Lake. Contouring the distribution of pyrope grains (1990) showed a concentration centered over an area of 616 km2 extending down-ice from Gauthier Township. This included a smaller area containing chrome diopside grains. Kimberlite boulders were identified (1981) in gravel pits on the Munro and Misema River Eskers located within this anomalous area. The next step would be to use the airborne geophysical data to locate the kimberlite pipes which yielded the indicator minerals and boulders. The source area is likely to be in the northern half of the Ontario Geological Survey study area."

Jan 1, 1992

By Robert B. Parsons

"In all likelihood, Canada's mining industry would be adversely affected by corporate tax reform proposals actively being considered by the Department of Finance in Ottawa. When the next set of proposals for lax reform is released later this year as promised by Finance, the mining industry had better be prepared 10 take a hard look.IntroductionTwo federal budgets ago, in May 1985, Finance Minister Wilson tabled budget papers that were more massive in terms of volume than most federal budgets. Buried in this mass of documentation is a discussion paper entitled ""The Corporate Income Tax System-A Direction For Change"". When the discussion paper was tabled over one year ago, reaction from the business sector was almost nonexistent. By and large, the paper was regarded as nothing more than one more federal publication of mild academic interest.But, recent events suggest that this discussion paper for corporate tax reform could be the cornerstone for a series of changes to the tax laws which would have more profound and widespread effects for all sectors of the economy than any reform since 1971 . No industry in Canada can afford to ignore the movement afoot in Ottawa for corporate tax reform."

Jan 1, 1986

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 M. J. Scoble, H. L. Francis, D. F. Salter, G. R. Baiden

Intelligent ore delineation refers to the ability reliably to characterize the geological setting of a mineralized body and its grade distribution. This necessitates using all available geological information in a timely and efficient manner, such that effective geological control is achieved. The importance of geological control is paramount to improving the efficiency and competitiveness of underground mines. As a result, the development of new geosensing tools designed to provide more reliable and timely information should be a priority. However, as the sensing tools advance then so, too, must the decision support system in order to allow the full benefits of these tools to be achieved. One potential system considered able to provide this architecture is ’true 3D-GIS’ (Geographical Information System). GIS promises to provide a seamless data flow and to connect information currently unavailable to the underground mine operations by bringing together previously disparate and spatial data sets in a visually effective and timely way. This paper considers the potential revolution GIS offers over the flow and use of data in mining by focusing on the integration of geosensing data and GIS to facilitate intelligent ore delineation.

Jan 1, 2000

By Binbin Luo, Northeastern University, Chuanyao Sun, Jie Liu, Yimin Zhu, Yanjun Li

"A series of new type collectors a-bromo-saturated fatty acids, CH3(CH2)5CHBrCOOH (a-BHA), CH3(CH2)7CHBrCOOH (a-BDA), CH3(CH2)9CHBrCOOH (a-BLA), CH3(CH2)11CHBrCOOH (a-BMA) were synthesized from saturated fatty acids and bromine by solvent-free method (Hell-Volhard-Zelinski reaction) in laboratory. The micro-flotation tests of quartz mineral were conducted at a relatively low temperature of 15 °C. The adsorption mechanism of such collectors on quartz mineral surface were established by zeta potential measurements, in conjunction with the results of quartz micro-flotation tests. The flotation results showed that the collecting ability is in the order of a-BMA > a-BLA > a-BDA > a-BHA for the flotation of quartz mineral, which also demonstrating that the a-bromo-saturated fatty acids (a-BFAs) are new selective collectors for reverse flotation to remove quartz mineral from iron ores at a relatively low temperature.INTRODUCTIONThe requirement of higher pulp temperature to maintain the activity of fatty acid anionic collectors which have been widely applied in technological process of iron ores reverse flotation lead to a great deal of energy consumption.The purpose of this paper is to synthesize a new modified collector with carbon chains from eight to fourteen atoms, with strong electronegativity bromine atom introduced into a-carbon position to improve the activity and solubility of the reagent so that it can be adopted at a comparatively low pulp temperature. The collecting performances of these new collectors on quartz surface were studied, and the structure - properties were discussed in light of zeta potential measurements and quantum chemistry calculations."

Jan 1, 2016

By K. Barron

"A computer program is described which will analyze the stability of coal pillars. The extent of the peripheral failed zone and the central elastic core of the pillar, the stress distribution across the pillar and its strength can be determined by a ""sliceby- slice"" analysis technique. The program incorporates a brittle/pseudo-ductile transition point so that a pillar may fail by brittle fracture or pseudo-ductile yield. It is shown that:(i) There is a minimum pillar stress below which fracture cannot initiate; hence there is a minimum pillar strength. (ii) In specific circumstances (narrow pillars) , once fracture initiates at the pillar edge it must propagate immediately to the pillar centre. This unstable situation is called ""catastrophic"" failure and might be regarded as a model of a pillar ""burst "". (iii) For wider pillars, the failed zone ex tends gradually into the pillar as the loading increases until it reaches the pillar centre when the pillar is deemed to have f ailed. This is called the point of ""ultimate"" failure.The critical pillar widths to avoid catastrophic and ultimate failure can be calculated.A hypothetical analysis of five rib pillars is given to illustrate the application and the results obtained from the model. The model is then used to analyze three case histories taken from the literature. The first demonstrates the applicability of the brittle/pseudo-ductile failure criteria for Pittsburgh coal. The second compares the pillar strength formulae derived here with those of Salamon and Munro(13) and Bieniawskiou . The final case history compares the model analysis with field stress measurements in a yielding pillar. In all cases the model results are compatible with the case histories."

Jan 1, 1984

By Denghong Wang

Abstract- The Ashele Cu-Zn deposit is a recently discovered volcanogenic massive sulfide deposit in Xinjiang, China, hosted by Lower to Middle Devonian submarine bimodal volcanic rocks. The primary ores of this polygenetic deposit are represented by massive syn-depositional pyrite, chalcopyrite, and sphalerite, and were formed by submarine exhalation. Hydrothermal alteration consists of strong sericitization, chloritization, silicification, and carbonatization of the metavolcanic rocks beneath the massive orebodies. Depletion of Na2O is an obvious chemical change in the hydrothermal halo. Geological and geochemical evidence suggest that the Ashele Cu-Zn massive sulfide deposit was formed by submarine exhalation related to bimodal volcanic rocks, trapped in a rifting basin, then deformed by shearing, and thermally metamorphosed by the intrusion of dacitic porphyry. Sulfur and lead isotopic studies indicate that metals such as copper and zinc may have originated from spilites, but that volatile components, especially sulfur, were derived directly from submarine volcanic magmas.

Jan 1, 1999

By John Campbell, William Trahant

"Total Quality Management (TQM) is becoming a reality in the mining industry. Widely adopted in the manufacturing and services industries, TQM has become the operating style of choice in numerous mining companies across the Americas and Australia. Iron Ore Company of Canada, Inco, MSA, Graniterock, Magma Copper, and CRA's Hamersly Iron - all are pioneers of TQM. These companies and others are confronting the challenges of implementing TQM and are managing the changes required of their people and cultures. What these companies are doing, why they are doing it, and how they are successfully managing the changes are the subjects of this paper.Driving the need for change in these organizations are a host of issues, some of which all mining companies are facing. Requirements from customers for ISO 9000 certification is becoming one of the initial motivators for Total Quality Management. These standards, commonly used in manufacturing throughout the European Community (EC), emphasize quality in the processes that create outputs, instead of just the outputs themselves. Iron Ore Company of Canada, for instance, responding to the requirement of one of its customers, British Steel, has become one of the first mining companies to meet the quality standard. Suppliers who meet the standards are highly desirable to customers who are themselves operating under the ISO or their national quality guidelines."

Jan 1, 1995

By D. H. Wilton, C. I. Godwin, A. J. Sinclair

"A computer-based drill core logging system used to examine computer-based drill core logging system used to examine copper mineralization hosted in volcaniclastic rocks at the Sustut deposit, in north-central British Columbia, has many advantages over conventional logging. A relatively simple format for recording geological information allows complex, but significant, geologic parameters to be recorded consistently, accurately and quickly. This allows graphical presentations and statistical interpretation of the data that lead to rapid and detailed analyses of the control and distribution of copper mineralization at the Sustut deposit.Ore mineralization is concentrated in lens-shaped bodies and is zoned from native copper cores through chalcocite, bornite and chalcopyrite to a margin containing pyrite. Chalcocite, the principal mineral, occurs mainly in volcaniclastic agglomerate characterized by a specific grain size, a narrow range of matrix and fragment proportions, and a specific sorting.IntroductionWe report here a case history of the practical application of a detailed computer-based drill core logging system applied to the Sustut copper deposit of Falconbridge Nickel Mines Ltd. The Sustut deposit, containing a few tens of millions of tons of ore grading slightly more than one per cent copper (Church, 1975), is in north-central British Columbia about 875 km north of Vancouver. The deposit is contained in volcaniclastic sedimentary rocks of the Upper Triassic Moosevale Formation, which is within the upper part of the Takla Group (Monger and Church, 1977) of basic volcanic and associated sedimentary rocks. Takla rocks occur along the eastern fringe of the Intermontane Belt in the Canadian Cordillera (Sutherland Brown et al., 1971). The deposit consists of concentrations of copper sulphides, native copper and pyrite within pods and lenses parallel to bedding in the host sedimentary rocks. These sheet-like deposits exhibit a mineral zoning from pyrite at the fringes successively through chalcopyrite, bornite and chalcocite to native copper at the core (Wilton, 1978; Wilton and Sinclair, 1979)."

Jan 1, 1980

By Y. Champoux, N. Atalla, R. Oddo, C. Lesage

"Percussion drills are the source of the most serious noise problems in mining activities, due to their extremely high noise levels(114-122 dB(A)) and widespread use(Bartholomae and Stein, 1988). Percussion drills will continue to be widely used to drill small diameter holes in hard rock because no other method seems to be economically avail-able to replace them (Boillat et al., 1993).Many studies (Danière, 1991; Hawkes etal., 1977a; Jensen and Visnapuu, 1972;Leblond et al., 1976; Milette, 1989) were con-ducted to determine the major noise sources of percussion drills. The exhaust air of pneumatic drills, the hammer, the bit in contact with the rock and the drill rod have been identified as the major noise sources. A muffer can be used to reduce the exhaust noise and the hammer can be enclosed. The bit noise is considered to be of concern only at the beginning of holes. When all the available methods are used to reduce the noise of a percussion drill, the drill rod vibrations become the dominant noise source (Hawkes and Burks, 1979). However, the noise levels generated by this source remain high and future efforts should concentrate on reducing its radiation.Works by Hawkes and Burks (1979) and Hawkes et al. (1977b) for the U.S. Bureau of Mines provide the most complete description on the noise and vibration of percussion drill rods.The longitudinal and bending waves are the two most important types of elastic waves generated in drill rods. Among these, only the longitudinal waves contribute to the drilling rate. The bending waves are caused by non-centralized impacts, drill rod curvature and non-uniform bit/rock interface. Drill rod noise is generated by Poisson’s ratio expansions and contractions of the rod as the longitudinal waves travel up and down it and by transverse rod motions induced by bending waves. The radiation efficiency is much higher for bending waves than for longitudinal waves. Most of the impact energy is transformed into longitudinal waves, as expected for axial impacts. The evaluation of the relative contribution of longitudinal and bending waves to noise generation poses a very difficult problem for experimental, analytical and numerical approaches. It is, however, an important issue because the relative contribution of these two waves will guide future noise reduction efforts. It seems that very little can be done to reduce the noise radiation of the axial waves without affecting the drilling rate. The main difficulty that analytical and numerical approach-es face, in the evaluation of the relative contribution of the two waves, is that there is no adequate theory for predicting the bending vibrations from the factors that cause them. The experimental approach has, thus, been limited to test fixtures that do not adequately represent the boundary conditions, as well as by measurements obtained under real operating conditions from which it is difficult to establish the relative contribution of the two types of waves. For example, Hawkes and Burks (1979) and Hawkes et al. (1977b) used a test fixture with free-free boundary conditions and made no clear link with measurement under real operating conditions. Rather, they have based their discussion on a simple model. Many authors assume that fexural waves are the main noise source on drill rods. However, measurements have been somewhat contradictory and researchers are still unable to state with certainty that this is indeed the case (Lednik et al., 1988)."

Jan 1, 1997

By C. Mills, A. O. Burt

"The paper examines the role of gravity concentration in both an historical context and within the modern mineral processing industry. It discusses the principles of the process on both a theoretical and practical level. The importance of more mineralogy and its effect on the choice of the wide range of equipment available is discussed. The paper concludes with a discussion on the relative merits of gravity concentration with other forms of processing.IntroductionIt is an unfortunate, albeit popular, misconception among otherwise enlightened engineers in the mineral processing industry that gravity concentration was a process developed in the dark ages, perfected in the middle ages, and abandoned in the modern ages.Gravity concentration was developed in the dark ages - long indeed before that. Agricolau: cited examples of gravity concentration, crude examples admittedly, being practiced over 3000 years ago. However, gravity concentration is not dead. Far from it. As recently as 1978 it was reported that the total mineral tonnage treated by this process in the United States was greater than that processed by flotation. Coal represents the bulk of the or e treated by gravity separation in the U.S.A., with iron ore representing a major portion of the balance."

Jan 1, 1985

By Eric D. Jamieson

"How well is the Canadian coal industry able to expand in the tough competition with other fuels in Canada and with other suppliers in the international, metallurgical and thermal coal trade? Coal production as a whole decreased between 1950and 1960 and, although there has been a tripling of production since then, underground production continued to decrease until 1975. This trend has been reversed to a certain extent as a result of the modernization of mines in Cape Breton, but in 1978 over 85% of coal production came from surface mining.Against this background, the paper reviews current Canadian mining operations as described in papers presented at the 1979 CIM Annual General Meeting. Conclusions are then drawn regarding some of the longer-term mining applications in relation to the latest coal demand forecast, which indicates a potential Canadian production requirement of 160 million tonnes per year by 2000. IntroductionThe Canadian 'coal industry is experiencing a period of expansion and a new record for production is set with each passing year. This growth pattern over the last IS years has been based on two main markets-the generation of electricity in Canada and the export of coking coal to Japan. Supply to those markets has entailed either the development of mining, coal preparation and transportation systems for the delivery of large volumes of products with predetermined specifications or the establishment of minesite plants designed specifically to suit the characteristics of the coal in the adjacent deposits (Fig. I).Coal is a low-value commodity in relation to its bulk, and the economics of coal use become progressively less attractive with increasing distance from the producing mine. The transportation component in the export trade and in the movement of western coal to Ontario is a major cost factor. In the latter case, it approaches the cost of coal produced at the mine. In addition, the .international competition among coking coal producers chasing diminishing markets in a worldwide steel recession as well as the competition from U.S. coals and other fuel s for Canadian thermal coal have introduced a tight set of parameters to govern mining practices in all parts of the country. Some appreciation of the required changes in mining techniques brought about by declining traditional markets and the rigorous demands of the new bulk markets can be gained by comparing production from surface and underground mines over the past 25 years (Fig . 2)."

Jan 1, 1980

By M. Celikin, M. Isac, R. I. L. Guthrie, S. Ge

Horizontal Single Belt Casting (HSBC) is a near-net-shape casting process in which molten metal is directly cast into thin strips, at high cooling rates (order of several 100°C/s), with the potential for high volume, friction-free, continuous production of metal strips. This casting process was used in the present work to produce strips of Al-Mg alloys in the AA5000 series, with additions of Sc and Zr. Such aluminum alloys show exceptional potential as a structural material for transportation/aerospace applications. To demonstrate the suitability of the HSBC process to manufacture competitive strip products of Al-Mg-Sc-Zr, the mechanical properties and microstructures of the strips produced using the HSBC process were compared with conventionally cast products. The effects of annealing on the mechanical properties of the strip-cast Al-Mg-Sc-Zr alloys were also investigated.

Jan 1, 2014

By P. K. Kaiser, D. D. Tannant

"A support system for large ground convergence conditions or burst-prone ground must contain holding elements (rockbolts, cable bolts, etc.) that are strong yet capable of sustaining large deformations, i.e., they must absorb as much energy as possible. Steel wire rope anchored in a borehole by a friction bolt provides these desired yield characteristics if the frictional anchorage is placed deep enough into the rockmass, i.e., in non-yielding rock or beyond the expected depth of rock ejected during a rockburst. Pull-out tests were conducted on wire ropes anchored by inflated Swellex bolts to assess the feasibility of this support concept. The test results demonstrate that a Swellex bolt generates a frictional anchorage that allows the wire rope to slide at high loads and to absorb significantly more energy than either a Swellex bolt alone, or a cement-grouted cable.The rope/friction bolt combination can be engineered to provide the desired energy absorption and allowable deformation by varying the installed lengths of the friction bolt and the rope. For yielding rope support, the contact length between the rope and Swellex bolt must be short enough to ensure that the rope can slip well before its tensile capacity is reached. A safe maximum overlap length is about one metre for the wire rope used in this testing. When used as support in the backs of drifts, a swaged button on the ropes end must be used to ultimately mobilize the full rope capacity thereby protecting against gravity-driven falls of ground."

Jan 1, 1995

By The Hollinger Mill Staff

MR. E. L. Longmore (l), in presenting this paper at the Annual General Meeting, suggested that it was neither desirable nor necessary to read any but the briefest portion of the paper. He wished to emphasize that the scale of the milling operations at the Hollinger not only provided several units in continuous operation to ensure that the test work was being carried on under normal conditions, but also provided a large and competent staff to supervise such an extensive experiment and to criticize intelligently the recorded results. He wished to acknowledge the enthusiastic co-operation of the group of assistants whose excellent work was responsible for the confidence with which the conclusions could be presented. The following data were given as a supplement to the published paper. Following conclusion of the test work described in the paper, the size of the balls fed to the mill was changed from 3-in. diameter to 2Yz-in. Within a short time, a gradual rise in the tonnage rate took place and, as no other condition had been changed, the increased tonnage was credited to the changed character of the ball load. At present, the average daily tonnage for the mill with low discharge is 1,507 tons, an increase of 77 tons over the 1,430 tons ground when feeding a 3-in. ball. A similar increase in tonnage should be credited to the high-discharge test, if the 2;Y2-in. ball had been used at that time. This would raise the 1,117 tons ground at that time to a new figure of 1,177 tons. From a study made to determine those factors influencing the rate of pulp flow through the low-discharge mill, it became evident that the ball screen used on the high-discharge mill must have been restricting the flow through the mill, although this was not recognized at the time. Accord-ingly, it was decided to repeat the high-discharge run. Additional length was added to the 21-in. ring grizzly originally used, and the length of the reverse spiral was increased. The end of the grizzly was left open so that, if necessary, excess pulp might flow out. A coarse mesh 3 ft. by 3 ft. flat screen was provided to catch stray balls.

Jan 1, 1937

By R. Walker

This paper deals with the selection and design of a belt conveyor handling steam coal between a mine and a barge loading terminal, and extending for some 5 ¼ miles over some of the most rugged terrain in the state of West Virginia, U.S.A. After a thorough analysis by consulting engineers and the owner's engineers, a single-flight cablebelt conveyor was chosen as representing the alternative of greatest reliability and lowest over-all cost. The value analysis and design features of the system are covered in this paper along with an updated report on the performance of the system since its start-up in the spring of 1969.

Jan 1, 1971

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

"Abstract - 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, Fe2O3 and 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 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