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By K. D. Card, K. Howard Poulsen

Abstract - The Archean Superior Province craton and the Paleoproterozoic Penokean Orogen are major geological sub-divisions of the southern Canadian Shield and account for much of the metallic mineral production of North America. The Superior Province experienced a mainly Archean history involving several cycles of volcanism, plutonism, and tectonism, primarily in the Neo-archean but also including Meso-archean and Paleo-archean cycles as well. Superior Province consists of northern and southern high-grade gneiss sub-provinces and a broad central region of alternating greenstone-granite and metasedimentary belts. The sub-provinces may represent tectonic terranes assembled in the Archean by accretion processes similar to those of some Phanerozoic orogens. Most of the mineral deposits, including VMS, intrusion-related, and lode gold deposits occur in the greenstone- granite sub-provinces where they were formed in an interval of 100 million years or less around 2.7 Ga. The Paleoproterozoic Penokean Orogen comprises supracrustal sequences deposited in fault-controlled epicratonic and rifted margin settings developed on and about the Superior craton. Deposition of the ~2.4 Ga Huronian Supergroup and its paleoplacer uranium deposits in the eastern Penokean Orogen, and their pre-2.2 Ga deformation, were probably unrelated to the deposition of the ~2.1 Ga Marquette Range and Animikie groups and their major taconite iron formations in the west. However, these sequences were deformed together during the ~1.85 Ga Penokean Orogeny which resulted when an assembly of island arcs containing VMS deposits, the Wisconsin magmatic terrane, collided with the Superior block and its Paleoproterozoic cover. The Sudbury structure with its world class Ni-Cu-PGE ores was also formed at this time, possibly triggered by meteorite impact. Metallogenic patterns in the Paleoproterozoic rocks were controlled by a complex interplay of factors including tectonically controlled variations in deposition and deformation, distribution of mineralization in the Archean basement, and oxyatmoversion, the transition from anoxic to oxygenic atmospheric conditions that occurred during the deposition of these sequences.

Jan 1, 1998

By Robert B. Parsons

"The Whitehorse Mining Initiative (WMI) brought together all of the key stakeholders in Canada's mining industry to develop a framework whereby the industry can meet the challenges that it faces into the 21st century. The WMI Accord7 which was signed at the annual Mines Ministers Conference in Victoria, British Columbia, on September 137 1994, touches all of the important issues that confront the industry, including taxation. IntroductionSeptember 13, 1994, was a historical day for Canada's mining industry. On that day, on the occasion of the annual Mines Ministers Conference in Victoria, British Columbia, the Whitehorse Mining Initiative (WMI) Accord was signed by the leaders of the five principal stakeholders in the industry: industry; government; labour; environmentalists; and aboriginals. The Accord is the culmination of two years of hard work and intense collaboration by these stakeholders. But, the Accord is not the end result. The Accord can better be described as a springboard to a prosperous future for mining in Canada.The WMI had its beginnings at the Mines Ministers Conference in Whitehorse, Yukon, in September 1992 (hence, the name of the initiative). At that time, the mining industry was well aware of the serious challenges facing the industry, including significantly increased competition for mineral investment from other mining countries, coupled with an atmosphere of uncertainty surrounding land access, environmental regulations, and taxation. The diversion of investment abroad was hurting, and would continue to hurt, all Canadians. Something had to be done. At the 1992"

Jan 1, 1994

By H. Soto, P. Lacombe, R. del Villar

"During the summer of1989, Les Mines Selbaie, with the cooperation of Université Laval initiated a research project to evaluate the column flotation technology for its concentrator near Joutel, Quebec. The experimental work involved both a 5 cm by 11 m laboratory column and a 45 cm by 10 m home-made pilot unit Amenability tests were conducted using both units on various streams of the plant. Results showed that columns are not suitable for the copper cleaning circuit because the loss of precious metals, associated with the rejected pyrite, overcome the improved copper metallurgy. On the other hand, column testing at the zinc circuit showed improved zinc selectivity.Scale-up testing was', therefore, conducted on the first zinc cleaner concentrate using the laboratory-size column. The influence of variables such as porous parger grain size, wash water flow rate, airflow rate and froth depth values on column performance was' first assessed. Scale-up parameters were then determined using the optimal operating conditions from the previous tests. Simulation facilitated the determination of the most convenient plant-scale column arrangement.A number of conclusions concerning the experimental determination of scale-up parameters are also presented."

Jan 1, 1993

By E. Kouame, M. D. Everell, D. Hodouin, T. Kasongo

"To properly operate a mineral beneficiation plant it is often necessary to have systematic evaluations of the performances of a piece of machinery, of one of the processes or of the plant as a whole. The state of a process can be described from a collection of data: flow-rate values, particle-size distributions and chemical compositions of the various streams of the circuit studied.However, the obtained raw data are generally redundant and inconsistent from a material balance viewpoint, due to natural disturbances, sampling errors, unreliable instrument readouts and laboratory analysis inaccuracies.BILMAT is a computer program which upgrades mineral processing data, adjusting them in a least-squares sense in order that they may verify material conservation constraints. As a consequence, the program is able to calculate the best values of unmeasured flow rates (such as. circulating load ratios). BILMAT is a very general program in the sense that it can accept various data from any type of mineral processing circuit, and its usefulness is demonstrated here for three processing circuits of a pyrochlore concentration plant: grinding, desliming and flotation.IntroductionComputation of the material balance around any metallurgical process, that is the determination of stream flow rates and composition. is a basic step in its evaluation. In spite of the simplicity of the physical laws of mass conservation. and of the very fundamental need to know the flow of components around a process. it appears, particularly in mineral processing. that material balancing is quite often a difficult task. The reasons for this involve the problems associated with collecting measurements in mineral dressing plants. They are generally poorly instrumented and invariably data must be collected through hand sampling. Due to the heterogeneous nature of the streams, segregation occurs and samples are often not adequately representative, a problem made worse by the lack of circuit sampling facilities, which are often completely ignored by plant designers. Furthermore, the nature of the measurements to be performed (for instance particle size distributions in the fine range) frequently gives inaccurate results."

Jan 1, 1981

By V. J. Hucka, J. H. Tu

"A computer model has been developed for evaluating the performance of truck and shovel operations in an open-pit mine. The data required for describing the haulage network are simplified and shift startup and ending procedures specific to any given mine can be incorporated into the model readily . The model uses a FORTRAN-based simulation language SLAM and can be tailored to the conditions and practices of a particular mine.The model is used to analyze truck and shovel operations, evaluate different haulage layouts in the planning stage, or compare the expected performance of alternative truck dispatching systems.Stochastic simulation is used to model the random variation in time required f or the individual activities. This gives a more realistic representation of the processes under study. Simulation runs show good agreement with actual performance. The model is especially useful for examining alternatives in equipment acquisition , haulroad design, truck-shovel allocation and dispatching methods. The results of such simulations provide a sound basis f or making major management decisions.IntroductionTruck haul age is widely used in open-pit mining operations. It is also the largest cost item in the operating costs of an openpit mine, in some cases accounting for an estimated 50% of operating costs(1) , Truck replacements, which are necessary from time to time, involve large amounts of cap ital. Increasing depth of mining and consequent increase in stripping ratios require additional capital investment in the truck-shovel fleet. The sharp rise in energy costs over the last decade has also contibuted significantly to an increase in truck fleet operating costs . All these factors have led mine operators to search for ways to improve the effectiveness of the truck-shovel fleet, in order to lower costs and maintain a profitable operation in the face of declining markets and increasing world wide competition.Control of truck haulage in an open-pit mine is usually done in one of two ways."

Jan 1, 1985

By James F. Kelly

"Research and development on the production of liquid fuels from coal is rapidly expanding worldwide. AImost every industrialized country is engaged in coal liquefaction research and process development. In Canada, the federal government, through CANMET, is actively supporting coal liquefaction research and development in a number of areas.A review of the basic principles and some of the processes in the production of liquid fuels from coal is presented with reference to the characteristics of the Canadian coal resource base. An overview of the CANMET coal liquefaction contract program is presented and specific results from the batch autoclave studies carried out with Saskatchewan lignite and Nova Scotia high-volatile bituminous coals are discussed. The development of a laboratory-scale continuous-flow coal liquefaction unit at the Energy Research Laboratories of CANMET to investigate the co-processing of coal and bitumen/heavy oil is also described.IntroductionThe CANMET coal liquefaction program is made up of two interrelated parts. The first part consists of the research and development work being carried out at the Energy Research Laboratories near Ottawa, Ontario. The second focuses on contracted research and development as part of the Coal Conversion Program of Energy, Mines and Resources Canada. The long-term objective of the liquefaction program is to contribute to Canadian liquid fuels production through the definition, research, development and demonstration of different coal liquefaction technologies for the Canadian marketplace.In coal liquefaction, the main objective is to produce liquid hydrocarbons with a higher hydrogen-to-carbon (HIC) ratio than the coal feedstock while reducing heteroatom (S,O,N) content, removing mineral matter and minimizing gas production. Typical atomic HIC ratios for a variety of Canadian fossil fuels are shown in Figure I. Canadian coals have about 500/0 of the HIC ratio present in tar sand bitumens and heavy oils and only about 20% of the ratio available in methane. In general, the cost of synthetic fuels production is related to the cost of hydrogen and, therefore, to the increase of HIC ratio between feedstock and products. On this basis, the production of liquid fuels from coal would be expected to be more costly than liquid fuels produced from bitumens and heavy oils. However, for mined tar sands and some heavy oils this difference tends to be offset by the large sand content (>90 mass %) of tar sand bitumens and the increased production costs of viscous heavy oils. For example, it can easily be shown that for equal weights of distillate <525°C) yield, current coal liquefaction processes required between two and three times less mined coal by weight than the mined tar sand s required for the most technically advanced processes proposed for bitumen upgrading."

Jan 1, 1981

By Hani S. Mitri

Overhand cut-and-fill mining of narrow vein orebodies inevitably leads to the creation of horizontal pillars. As the thickness of the overlying crown pillar diminishes, stresses build up in the pillar. More often than not, this situation causes an increased level of seismicity and possible pillar burst. One well-known strategy to reduce the hazard of crown and sill pillar burst in cut-and-fill vein mining is that of destress blasting. The paper first reviews the methods used for the monitoring and assessment of potential pillar burst in narrow vein cut-and-fill mining. The influence of horizontal stress, mine depth and pillar thickness on stress build-up in the crown pillar is examined through a characteristic narrow vein numerical model. The paper then presents, with reference to three mine case studies, the benefits of destress blasting and the factors affecting its success as a ground control technique.

Oct 1, 2001

By C. T. Dzgoev, S. S. Gudkov, IRGIREDMET JSC, S. G. Schtoick, A. V. Yepiforov, S. V. Balikov, I. I. Yevtuschevich

The pressure oxidation (POX) and pyrometallurgical process comprises POX of gold containing sulfide and polymetallic lead-zinc concentrates prior to reduction smelting of POX products to generate a lead-silver-gold alloy. Refined lead and gold-silver alloys are then obtained using conventional processes. Zinc and other base metals are recovered from the POX solution. In the course of POX, zinc dissolves in the solution and lead concentrates in a solid residue in the form of sulfate compounds. Sulfur forms the major iron sulfates and jarosites. In order to dissolve sulfur and arsenic from solid residues to the solution, the slurry hot curing was carried out at the temperature of 95°C within 2 hours. After filtration of the slurry, zinc was recovered from the solution. The resulting cake was washed with water and subjected to hot alkaline treatment. After alkaline treatment, the cakes were blended with fluxes and subjected to reduction smelting to generate lead concentrate containing precious metals. This concentrate was refined to obtain refined lead and gold-silver alloy. After iron and arsenic were removed from POX solutions using sodium carbonate, zinc was precipitated as carbonate. After thickening and filtration, zinc precipitate was roasted to generate saleable zinc oxide. Using this process, the recoveries of values to saleable products were 97% Au and 95% Ag to the alloy, respectively, 91% Pb to refined lead and 5% Pb to lead and antimony alloy and 94% Zn to zinc concentrate. The features of the technology is that it has high recovery indices of precious and base metals to saleable products and can be used to process various polymetallic ore and technogenic raw materials.

Jan 1, 2016

By B. Galy, L. Giraud

"This paper compares Canadian provincial mining safety regulations regarding the use and testing of cage safety catches, including a brief history and evolution. Regulations are similar across provinces, with only slight variations. Currently, the “Ontario-type” safety dog is the most commonly used safety catch in Canada. Performance estimation of the compensation mechanism for different safety-dog shapes and tooth angles show this shape works well and has consistent braking results, but the best efficiency is obtained for initial tooth angles greater than 10°. Miner safety is questionable for lightly loaded cages, an issue that should be addressed technically and legislatively.RÉSUMÉ Le présent article compare les diverses réglementations de sécurité minière concernant les parachutes des cages dans les provinces canadiennes ainsi que les essais qu’ils doivent subir. Il semble que les réglementations soient semblables à travers les provinces avec quelques légères différences ou divergences. Un bref historique des parachutes et de leur évolution est présenté. De nos jours, le parachute de « type Ontario » est le plus fréquemment employé à travers le Canada et il présente des résultats de freinage uniformes. Une estimation de la performance du mécanisme de compensation pour les diverses formes de taquets de sécurité et les divers angles des dents montre que cette géométrie fonctionne bien; cependant, la meilleure efficacité est obtenue pour des angles de dents supérieurs à 10°. La sécurité des mineurs est mise en jeu pour des cages faiblement chargées et ce point devrait être traité du point de vue technique et du point de vue législatif."

Jan 1, 2016

By A. Christoffersson, T. Nillson-Wullf, H. R. Manouchehri

"Mining industry has been the building blocks for human development through millennia and will continue to play its role in sustainability and meeting society’s needs for raw material. In the way towards sustainability, the next generation of efficient and heavy duty of Sandvik’s crushers, CH860 and CH865, are introduced for efficient crushing. As the secondary, tertiary and/or pebble crusher, these new crushers are designed to over perform in tough mining environment. Featuring higher crushing forces relative to the mantel diameter and 500 kW motor, combined with advanced automation system, i.e., sophisticated HydrosetTM and Automated Setting Regulation (ASRTM), combined with overpressure system with dedicated air supply in dust collar, etc., the new crushers provide higher safety, productivity, and reliability with the same foot-print of conventional cone crushers.Since crushers are more energy efficient than mills it makes sense to effort in fine crushing to save energy and protect environment. That has been the logic behind development and introducing stronger and more efficient crushers by Sandvik. The results on crushing hard iron and gold ores by CH865 have proven its efficiency in fine crushing at a higher productivity, availability and reliability rates through increasing throughput for defined size fraction and extended crushing chamber liner life.Within this paper the performance of the CH865 to deal with two different ores are presented discussed with a glance at how the downstream milling process can be benefited by saving energy and reducing the operation cost. In plant practice, the implementation of the new CH865 provides between 25 and 30% of the crushed ore in the size range of first step milling, i.e., < 2 mm, that offers opportunity for reduction in energy consumption in milling and even changing the process plant configuration by directly forwarded that part to gravity separation. Furthermore, potential of converting the rod mill to ball mill to improve productivity has been considered by plant engineers. Furthermore, some potential applications for such efficient crushers are brought into considerations and discussed. The new developments provide about 30% higher crushing force to efficiently deal with competent ores and pebbles. The CH860 and CH865 crushers are well suited to replace conventional secondary and tertiary crushers respectively; nevertheless, CH865 is virtual option for pebble crushing in SAG and AG milling circuits."

Jan 1, 2016

By G. W. R. Kuzyk

"Hydraulic drills, recently implemented at the Tantalum Mining Corporation of Canada, Limited, Bernie Lake Mine, are proving to be an economic alternative to pneumatic drilling systems. The paper describes the application of an electric-hydraulic drill jumbo to the mechanized room-and-pillar mine and its performance. The application of these drills resulted in improved environmental and working conditions.Drill rods and bits are a major cost centre in hard-rock mining applications. The paper also discusses the performance of one manufacturer&apos;s product used on the hydraulic drills.IntroductionThe Tantalum Mining Corporation of Canada, Limited (TANCO) started producing tantalum ore from its Bernie Lake pegmatite in 1969. The pegmatite, encased in amphibolite, is shallow seated and flat lying. It is defined by diamond drilling along 4,000 feet of strike and 1,500 feet down dip, ranging in thickness from 60 to 280 feet. Relatively well defined zones of mineralization occur within the pegmatite and form separate orebodies of tantalum, lithium and cesium."

Jan 1, 1981

By Earl Gebhardt

"The planning and design of mining panels in the Potash Corporation of Saskatchewan Inc., Lanigan Division mine Block B involved a number of investigative techniques. The techniques utilized to gain insight into the viability of mining included2-D and 3-D seismic surveys, longhole drilling, exploration wells, photo lineament, magnetic and gravity surveys, and actual room excavation.IntroductionPotash Corporation of Saskatchewan Inc. (PCS) owns and operates four potash mines in the province of Saskatchewan. The Lanigan Division mine is located 110 Ian east of Saskatoon, Saskatchewan, near the town of Lanigan.The Lanigan Mine commenced production in August 1968under the ownership or Alwinsal Potash of Canada Limited. The mine was purchased by PCS in 1977.Lanigan Division&apos;s productive capacity is 3.4 million tonnes of product per year. Ore is extracted from the "" B"" zone or Layer III or the Patience Lake member of the Prairie Evaporite, more than 1000m below surface . The Patience Lake member (approximately 20 m thick) consists of potash interbedded with salt. The average run-of-mine ore grade is 21070 K20 (Fig. I).The mine was initially developed using the room-and-pillar technique. Improvements in mining resulted in the use or extensible conveyors in long panel rooms."

Jan 1, 1993

By S. Jeon, T. H. Kim

"Understanding the frictional properties of discontinuities is crucial to ensure the stability of underground structures. In particular, the frictional behavior at depth depends on the complex interaction among mechanical, hydrological, thermal and chemical characteristics and their coupled effects. In this study, a series of triaxial compression tests were carried out to investigate the behavior of rough shear surface of synthetic rocks. The frictional behavior showed little variation at different confining and water pressures. The test results were analyzed using Coulomb’s failure criterion. In addition, numerical analysis was carried out using PFC2D to simulate the test.INTRODUCTIONUnderstanding coupled behavior of rock at depth is of great importance in design, construction and operation of underground structures such as a disposal facility of radioactive waste, hot dry rock geothermal system and oil reservoir. In particular, many uncertainties are involved in characterizing deep rock mass deformation in the designing process and interactions among fluid flow of groundwater, high temperature and stress disturbance should be considered. Many independent studies have been carried out to investigate the thermal, hydro, mechanical and chemical coupled effects in numerical and experimental methods. They include the researches by Lockner, Summers, Moore and Byerlee (1982), Jafari, Amini Hosseini, Pellet, Boulon and Buzzi (2003), Tembe, Lockner and Wong (2010), Lee, Lee and Jeon (2012), Indraratna, Premadasa, Brown, Gens and Heitor (2014)."

Jan 1, 2015

By G. Avramovic-Cingara, H. J. McQueen

The microstructure of commercially pure aluminum was investigated by using polarized optical microscopy (POM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM) techniques. Specimens were deformed in torsion at 400°C and equivalent strain rate of 0.1 s-1, to various strains of 0.2, 0.5, 1, 4, and 6. The results indicate that POM can usefully reveal grain and subgrain structures over a large field in aluminum. TEM is most suitable to study dislocation substructure and evolution of subgrains. While TEM microscopy and OIM are capable of resolving individual subgrains, OIM can not reliably distinguish subgrains with small misorientations, particularly in samples with low strain. On the other hand, the OIM technique is very useful in the analysis of many regions surrounded by high, medium, and low angle boundaries (HAB, MAB, LAB). Various misorientation maps were studied using different data processing methods. The analysis revealed that the subgrain size is relatively insensitive to strain. The fraction of low LAB ( < 5°) decreased and HAB (>15°) increased conversely with increasing strain, whereas MAB (5-15°) remained stable. The development of an increasingly bimodal grain boundary misorientation distribution is consistent with the predominance of dynamic recovery (DRV) in the evolution of microstructure, combined with geometrical dynamic recrystallization (gDRX), now called grain-refining DRV.

Jan 1, 2006

By W. F. Giuvlore, E. Mcroberts, T. S. Golosinski

"The rising demand for Canadian coal and depletion of shallow deposits, most suitable for surface mining, result in rapidly increasing volume of waste materials which have to be moved by the coal mining industry. While at present this challenge is being successfully met using conventional mining methods, in the future, innovative methods must be considered if Canadian coal is to remain competitive.The need for more efficient mining methods is also faced by the oil sands industry to assure competitiveness of the synthetic oil price.A look at the world mining practice indicates that large volumes of material can be economically mined and moved by the continuous mining systems comprising bucket-wheel excavators, belt conveyors and stackers. To assess the state of art and applicability of this mining method to Canadian conditions, the field trip was organized by the Department of Mining Engineering o f the University of Alberta, to several typical mining operations in Europe. It is in Europe where the continuous mining methods were developed and are almost exclusively used in large-scale surface mining."

Jan 1, 1984

By O. Kodym

The paper has focused on possibilities of interconnecting information sources concerning monitoring & control of mining industry technical processes (TP), and the related safety hazards. The key issue is the comprehensiveness of the information presented to users. Information can be presented by virtual reality means, when the seemingly true presentation of the production process scene along with user friendly presentation of related information is available. The user in its role of a process supervisor is not only a mere scene observer but, thanks to the interactive functions of virtual environment, he participates in the scene of his control. As such his control and management abilities increase because he can absorb, more easily understand and asses the information provided.

Aug 1, 2013

By V. H. Valenzuela

Materials in process or in stocks are quite relevant items in almost every plant, particularly in mining operations, where efficiency in rate of recovering material of interest becomes a key issue when production costs are evaluated. A manager requires information to do an effective use of the resources, especially when raw materials are involved. Losses associated to leaking, efficiency in the transformation process, performance of equipment, and operating conditions are a short list of items which must be properly identified and evaluated. Operations supervisors require information in order to keep key process variables under control. Because of these information needs, it is absolutely necessary to carry on a series of activities related with installation and maintenance of measuring equipment, sampling equipment, sample preparation, chemical analysis, statistical analysis, data handling and reports generation. These pieces of data must be managed on a wise manner in order to get the most of it, keeping always on mind data reliability. Normally, information related with metallurgical balance and even more, the metallurgical balance concept, is handled under an accounting criteria which does not allow dealing with the real world. This situation happens because the criteria utilized do not consider aspects such as bias and uncertainty associated with every measurement that affect the quality of the information and therefore conclusions drawn from it. The purpose of this paper is to give a few rules, necessary to follow, in order to develop an adequate Metallurgical Balance System for an operational point of view. The Gaussian approach for error propagation is used as a basis, allowing one to know the actual uncertainty of the balance and the way how it can be improved. A few real applications of this concept are listed, detailing experiences obtained from practice.

Jan 1, 2007

By W. Zieman

"The low consumption of reagents can probably be attributed to a good clean type of ore. The cyanide level is kept at 0. 8 lb/ ton of solution and the lime at 1. 8 to 1.9 lb per ton of solution (pH 12. 2 to 12 .3). Experience in cutting down the lime level in half produced troubles in the presses, in the refinery and resulted in higher cyanide consumption. Finally the residue increased under these conditions, High lime always seems to prevent the trouble from occurring.A survey at one mine of the taxable work, performed in the mine shops for use in the mine, showed that under the new regulations, this had increased some 30 times what it was before the new rules came into effect on June 14, 1963.A water softener idea is incorporated at Lamaque with the crude addition of 100 lb of lime per shift to a spare agitator to precipitate the bicarbonates as carbonates from the water before it enters the mill. The lime titration of the softened water is about 0,2 to 0.3 lb per ton of solution (pH 11). This water is used mainly on the filters as washes."

Jan 1, 1964

By Harold L. Gibson, David H. Watkinson

"Volcanogenic massive sulphide deposits of the Noranda Camp cur throughout the Noranda Shield Volcano but are concentrated and along the margins of the Noranda Cauldron. The deposits are realized along synvolcanic faults that also accommodated subsince and controlled the location of eruptive centres. Deposits within e 3 000 m thick Mine Sequence formed during a period of active volcanism and subsidence coinciding with the onset of two cauldron subsidence cycles. The Noranda Cauldron was a restricted site of 10malously high heat flow and structural permeability that favoured e development of a high-temperature hydrothermal system. Metals may have been derived from leaching of aquifer rocks by convecting a water or directly from a shallow underlying magma chamber, now presented by the Plavrian Pluton, that was at its highest position !thin the crust during cauldron subsidence. The deposits formed rough a combination of sulphide precipitation from exhaled fluid td replacement at and below the seafloor in a manner analogous to ose on the modern seafloor.RESUMESi les dépôts de sulfures massifs volcano gènes du camp minier de ~uyn-Noranda sont présents dans les différentes parties du volcanluclier de Noranda, ils se trouvent concentres toutefois, en plus ·and nombre, sur le pourtour de la caldeira (cauldron) de Noranda. ~s dépôts sont localises le long des failles synvolcaniques qui ont cilite la subsidence et contrôle la position des centres d’éruption.~dépôts situes dans la séquence des mines (3 000 m d’épaisseur) sont formes durant un épisode d' activité volcanique et de subsiden qui coïncide avec l' amorce de deux cycles d' affaissement de la rldera (cauldron) de Noranda. Celle-ci Jut le site exclusif d’unflux : chaleur anormalement élevé et d’une perméabilité d’origine cucturale qui ont favorise le développement d’un système hydrothermal a haute température. Les métaux proviennent soit directement d’une chambre magmatique situee afaible profondeur, so it d’un lessivage des roches de l’aquifère par l’eau de mer circulant par convection. Cette chambre magmatique, représentée maintenant par le pluton de Flavrian, se trouvait à son niveau le plus élevé dans la croute au moment de l’affaissement de la caldeira (cauldron). Les dépôts se sont constitués par un mecanisme combinant remplacement et précipitation de sulfures à partir des fluides exhalatifs, au niveau ou au-dessous du plancher océanique, de la même manière que se forment de nos jours, les dépôts de sulfures massifs au fond des océans."

Jan 1, 1990

By T. L. Tanton

"The New Helen mine is 12 miles east of Michipicoten harbour on lake Superior. It is 2 miles east of Wawa station, on the Algoma Central railway, with which it is connected by a spur line railway and a highway.The mine was discovered by Ben Boyer in 1898 during the gold rush near Wawa lake, Ontario. The original discovery was of solid hematite ore extending to a height of 100 feet on a hill rising abruptly on the east side of Boyer lake. The property was acquired by the Algoma Steel Corporation and mining was commenced in 1899. The first iron ore was shipped in 1900. The mine was operated until 1918 when the hematite became exhausted at a depth of 800 feet below Boyer Lake level.Drilling at the Helen mine, after 1910, revealed a large body of siderite both below and to the east of the hematite. By 1913, the body was known to be about 200 feet wide, 3,000 feet long, and at least 2,200 feet deep. In this there was estimated to be 100,000,000 tons of proved and probable siderite ore. An adit was driven into this body in 1917, and in 1918 work was suspended. In 1937 the Algoma Steel Corporation proceeded with the development of the New Helen mine by open-cut mining, and the beneficiation of the ore by sintering. Production commenced in 1939 and has since been maintained at the rate of approximately 500,000 tons a year.From 1900 to 1918, inclusive, the total production from the Helen mine was 2,823,369 tons of hematite ore and 51,930 tons of pyrite. From 1939 to the end of 1945 the total production from the New Helen mine was 3,921,455 gross tons of siderite ore.GEOLOGYThe Helen property is underlain by rocks of Precambrian age. For general description, and a statement on the structure of the iron deposits, the map-units are those shown in Fig. 1.The oldest rocks occur in a complex that lies north and south of an east-west trending zone, 1 ½ miles long and ¼ mile wide, in which the iron deposits occur. That part of the complex lying south of the iron deposits includes small masses of altered conglomerate and slate, and greenstones and pyroclastics. Other fairly abundant rocks are sericitic, chloritic, ottrelitic, and carbonatized schists of doubtful origin, and almost massive metamorphic rocks in which a development of carbonate, ottrelite, quartz, and other minerals has obscured a pre-existing schistose structure. Felsite and quartz porphyry are· prominently exposed south of the iron deposits."

Jan 1, 1954