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By Harold Hopkins

THE Wright-Hargreaves mine is one of a group of seven mines long active in the Kirkland Lake district, Ontario. Detailed geological reports and maps covering the area have been published by the Ontario Department of Mines (1,3)t. Though all these mines work several productive veins there is one vein which is common to all and is known as the North Vein of the camp?not that it is the most northerly vein mined, but it is the more northerly of the two major veins of the camp. At the Wright-Hargreaves mine there are in all ten important producing veins, and most of them have a N.60°-65°E. strike and in general a steep southerly dip. It is a common belief that most of these veins lie along faults but it will be shown that whilst this is true of some of them it is not true of all, and also that a vein may lie in a fault along part of its course and elsewhere fill a fracture in line with the fault, this being a consequence of rotational movements that took place during faulting. The paper describes the history of faulting at this mine in particular, makes observations on the principal pre-ore fault, and describes the method used in solving the movements on the post-ore faults. Other details of geology are not discussed except to mention here that our main veins lie almost entirely in the syenite porphyry stock except on lower levels close to the east boundary of the property, where the North vein leaves the porphyry to enter the greywacke.

Jan 1, 1940

By Daniel J. Corkery

Mines in Canada and the United States are subject to regulations limiting ammonia, nitrate and nitrite levels in mine effluents released into the environment. The primary source of these nitrogen compounds is typically explosive used in blasting operations, as ammonium nitrate (AN) remains a significant component of most explosives used in the mining industry. The amount of AN entering a local water drainage system is related to site conditions, explosives used, explosive handling and blast efficiency. Mining operators acknowledge AN loss to mine water from blasting operations. However, the mechanisms by which ammonia, nitrite and nitrate are entering the water drainage system, or the relative contribution of specific mechanisms, may not necessarily be assessed or monitored adequately. Characterization of these mechanisms, through systematic investigations, allows a mining operation to focus its efforts on reducing AN loss. This paper outlines a strategy for investigating the mechanisms through which AN enters the mine water drainage system and methods to mitigate this loss. This strategy includes collection and analysis of data to identify and quantify the AN loss mechanisms, design and implementation of tests to mitigate this loss, and assessment of the results. Such investigations are not intended to be a separate one-time project, but part of a long-term process of continual feedback and optimization that is related to the collection and reporting of AN levels for regulatory purposes. The implementation of the strategy must be tailored to each mine?s requirements and existing conditions.

Oct 1, 2010

By C. H. Wright

Introduction The rapidly expanding and increasingly complex Canadian industrial structure, with the mining, metallurgical, and chemical industries as a large integral part, has, in recent years, brought greatly increased importance and value to our industrial minerals. In the modern economy of our mineral industry the importance which is due the non-metallics has been somewhat overshadowed by the great value of our large metal production and, in addition, by the glamour and fascination usually associated with the mining and treatment of gold ores. The term 'Industrial Mineral' is used in this paper in its usual sense and refers to non-metallics other than fuels. Coal and petroleum products, including natural gas, are considered as industrial minerals in those applications in which they are used for strictly chemical process purposes. Certain reduction metallurgical industries are so closely allied to chemical industries that for purposes been of this discussion no attempt has made to differentiate between them. Chemical industry in Canada today is a fairly large factor in our national economy, whereas in 1898, when the Canadian Mining Institute was born, it was very small indeed. Chemical concerns are largely dependent on industrial minerals for raw materials and process supplies and, as the country has developed industrially, so have the demands for non-metallics increased, not only by chemical industry but also by other large consumers, such as the construction and metallurgical industries. At the present time there is a greater than normal incentive prevailing for new discoveries, due to the serious lack of balance that exists in our import and export trade. This fact has resulted in intensive efforts to rectify the situation by locating new deposits and re-assessing those already known in an effort to enlarge and improve our home production of raw materials and also to extend their processing in Canada for our own needs and for export. The rapid advances in science and technology that have taken place since 1900 have also resulted in many cases of beneficiation and utilization of otherwise too low grade materials in order to satisfy current demands. The purpose of this paper is to indicate the history and the trends of the utilization of industrial minerals in established industry and to indicate the important part played by non-metallics in connection with the opening up of new industries. Some consideration has been given to the continual competition between natural and 'synthetic products and to the general tendency towards more rigid specifications.

Jan 1, 1948

By S P. Giambra

The 50,000-ton-per-day Concentrator and Crushing Plant, complete with its related water supply, tailings disposal and concentrate handling systems, was started up in a five-month period, with the entire plant obtaining its design capacity six months after the first mill became operational. Individual mill lines, with their spiral circuits, achieved design capacities within a week after the first treatment of ore through each mill. Construction and start-up proceeded together in many areas of the plant, and considerable organization and cooperation between the Owner, the Engineer and the Contractors permitted a smooth transition from construction to operation. PLANT DESCRIPTION THE Carol Lake Plant of the Iron Ore Company of Canada l1as been well described in various technical magazines. The purpose of this paper is to present a brief outline of the start-up of the con-centration complex. This start-up was accomplished in a period of five months, with the plant producing one million tons of concentrate and achieving its design-rated tonnage less than six months after the first ore was treated.

Jan 1, 1963

By David R. Lentz

Abstract -At True Hill in southwestern New Brunswick, low-grade porphyry-style Bi-Sn-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 mineralization. ln a zone doser to the host rock­ granite 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 subangular 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 magrnatic-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 hydromagrnatic, low­ temperature fluid circulation and/or boiling along faults near the contact. These magmatic­ hydrothermal and hydromagmatic mesobreccias are similar to those associated with W-Mo-Bi porphyry-greisen mineralization at the Mount Pleasant deposit.

Jan 1, 1994

By Oliver Hall

WITH the friendly consent both of the Institution of Mining and Metallurgy, for whom this paper was written, and of the author, we had the pleasure of publishing Mr. Oliver Hall's paper on Mining at Noranda in our issue of last March and of having Mr. Hall present it at the Montreal Meeting. In the following pages we now report the discussion elicited by the paper at a meeting of the Institution in London on March 18th. The report is taken from the April, 1937, issue of the Bulletin of the Institution, to whom we again tender our thanks. THE PRESIDENT (MR. ROBERT ANNAN) said that this paper was, by arrangement with the Institution and the author, also being published by the Canadian Institute of Mining and Metallurgy for approximately simultaneous discussion. He was sorry that Mr. Oliver Hall could not be present to introduce it in person, for he was sure that the author would have had many more details to give about this most interesting mine. The paper contained a very useful account of mining operations, and personally he had been pleased to see the tri-dimensional projections of the orebody in Figs. 3 and S. It was a good illustration o the value of that method in presenting the form of an orebody such as this. While he had no desire to go into technical details, he wished to call attention to a remark in Mr. Hall's introduction, in dealing with the history of the mine and the principles on which it was run. The author had given an account of the early difficulties in solving geological problems, and later of the economic difficulties of seeing this mine through a period of intense depression in metal prices. He stated that it was clear that, to maintain income, tonnage must be increased, and, to maintain profits, costs must be decreased. It would be observed that there was no question of increasing the grade of ore. Then the author went on to say: 'Having set the house in order in the years of adversity, the higher price for gold is being used to mine to still lower limits and lengthen the life of the enterprise and the welfare of those dependent on it'.

Jan 1, 1937

By Edward I. Renouard

"THE mineral industry is constantly undergoing changes and facing challenges, and today we are in the midst of another serious one -namely, manpower requirement at every level in the mines, shops and plants. In the not too distant past we had a situation where labour was plentiful, although the equipment, by present-day standards, was quite inadequate, and that's easily understandable when you look back at the primitive methods by which our Western mines were first developed and operated, and then improved by the inventiveness and ingenuity of man.I'd like to show you a few slides from drawings made by Buck O'-Donnell which illustrate some of yesterday's methods of mining. Some of you probably had first-hand experience with some of these so you know they were tedious, time-consuming and involved a lot of heavy labour.Taking the Anaconda Company operations at Butte as an example, we can see what has happened in just the past ten years. In August of 1956, the Butte mines had 5,516 day's-pay employees and 976 salaried employees, for a total payroll of 6,492. In August of this year, there were 3,645 day's-pay employees and 605 on the salaried roll, for a total of 4,250. The number of contract miners had gone from 1,347 in 1956 to 606 in 1966 and that of other underground miners from 2,893 ten years ago to 1,149 this year. Along with these changes, however, another change of special significance has taken place, and that is in the number of skilled craftsmen, surface engineers and so on required for our operations. In 1966, we had 1,890 of these people, 600 more than in 1956 and nearly three times as many as just twenty years ago."

Jan 1, 1967

By Peter Silveston, Earl Shannon

Process-oriented experiments on the use of coal as an adsorbent for certain soluble components of sewage are described. The capacity of Canadian coals for these components was less than 0.1 per cent by weight for the highest concentration at which these components could be expected to be found in domestic sewage. This is much less than values reported in the past. A pronounced selectivity between components was observed. Experiments on bacteria removal in beds of coal, regeneration of spent coal to restore adsorption capacity and COD contributions of coal are reported in the paper. The simple application of coal as an adsorbent does not seem promising.

Jan 1, 1970

By T. Banerjee, R. deS. Almeida, D. Gudgeon, F. C. F. Batista, L. deÁ. Silva

"Yamana Chapada’s mine is one of the larger copper-gold mines in Brazil. The mine is located in Goiás state, in the central part of Brazil. The mine has estimated Mineral Reserves of 4.1 million ounces of gold and 3.2 billion pounds of copper as of December 31, 2016. While gold and silver are significant, Chapada’s process flowsheet is configured closer to that of copper facilities. This includes a SAG/Ball configuration for grinding followed by flotation. In the case of Chapada, the mineralogy results in higher-than-normal complexity, notably a significant circulating load both in the grinding and flotation circuits. From an operating perspective, the complexities are controllable, but require careful attention to ensure that circulating loads are effectively managed and gold is not lost to tailings. Chapada created an automation roadmap in 2016 designed to increase plant performance (tonnage, recovery and efficiency). Based on strong potential, the project was fast tracked and within 4 months instruments were installed, control algorithms implemented, and training sessions took place to ensure sustainability at site. This paper will follow the Chapada journey from identifying the opportunities through to implementation and testing.IntroductionYamana Chapada mine is a Copper-Gold mine located in Goiás State, Brazil. Although the mine contains large quantities in Mineral Reserve of gold (4.1 million contained oz as of December 31, 2016), Chapada is primarily a copper mine with copper principally found as chalcopyrite. Accordingly, the processing flowsheet at Chapada is comparable to that of other copper mines with a SAG and Ball mill each partnered with a cyclopack, followed by a flotation circuit. While the overall design is conventional, the mineralogy at Chapada results in significant circulating loads both in the grinding and flotation circuits. This does introduce certain complexities for operating strategies and practices, but, importantly, favourable recoveries and elevated processing rates can be maintained, albeit they need to be closely managed. Plant automation helps in this regard."

Jan 1, 2018

By Blaycock. S. C.

WE should indeed feel proud and satisfied with the accomplishments of our great mining and metallurgical. industries during the past quarter of a century, for they have vastly exceeded those of any previous period of like duration. 1 feel that Canadians, and particularly those in the mining industry, should know more concerning the important role our industry will be called upon to play in the present war. Our Empire metals will be an outstanding factor in this conflict. Every man connected with the industry, from the lowest paid labourer to the highest official, can feel proud that his every effort results in more and more production of those metals which will help to give the Empire supremacy. He can feel assured that, by sticking to his job and by putting his whole heart into his work, he is making a contribution towards winning the terrible struggle in which our Empire and our gallant French allies are engaged. These two great peoples will have ro bear the brunt of the task of ridding the world of the menace of those who would set up force. and might in the place of right and justice in the settlement of international affairs. As the present European crisis developed, it became evident that they, alone, would have to accept the challenge and fight the enemies of Democracy to ensure the survival of the small nations of Europe and, indeed, of the great democratic powers themselves. The acquisitive eye of the German leaders had looked far ahead and they had realized that the eastern European states, already reeming with population, were no solution to Germany's space problem; but they thought that these states could be gobbled up one by one, each in turn strengthening Germany's might until it could successfully challenge France and England. No glimmer of doubt dimmed their vision. The two great democracies once subdued, they could proceed to seize Canada and the United States. This clone, they would have an abundance of room to expand, as well as those resources-grain, timber, cotton, nickel, iron, lead, zinc, copper, gold, silver, sulphur, oil-which German statesmen have always coveted. Von Ribbentrop, von Alvensleben, Bernstorff, and many others have made exhaustive studies of our resources. German rulers had been told that the French would not fight and that the British could not. They knew of the rust on the British war machine. There was no cloud in the sky; their fond dream was at last robe fulfilled.

Jan 1, 1940

By C. Greimel

Modern roadheaders provide a safe and cost-effective, yet very flexible way of mechanical tunnel and roadway excavation. In the last years, SANDVIK Mining and Construction has developed a NEW ROADHEADER GENERATION, which incorporates new features, allowing significant improvements of underground excavation. Partial face cutting machines such as roadheaders excavate the desired profile by means of a cutter unit mounted on a swiveling boom. This flexible method for mechanical excavation makes the roadheader suitable for a large range of profile varieties and most rock characteristics. Over 1,250 roadheaders have been delivered since the 1960s from the Zeltweg plant of Sandvik Mining and Construction, with the current products ranging from the light-duty, 130kW MR220 machine, widely used in the tunneling and coal industry to the heaviest 300kW tunneling and hardrock mining roadheaders. Roadheaders are generally used in coal mine development, salt/potash mining as well as construction and hard rock mining. This paper describes the technology behind the succesful introduction of hard rock cutting with roadheaders, and aims to offer best practise operation experiences from various hard rock cutting sites.

Oct 1, 2010

By A. B. Morrow

Consulting engineers are well aware of large variations in plant operating cultures between countries, companies, and even within sites and operating crews. These operating cultures must be considered when designing Advanced Process Control (APC) applications in order to maximize utilization rates and return on investment. Designs must be driven by an understanding of the totality of unit operations. Economic factors, equipment constraints, management philosophy, maintenance department responsiveness, instrumentation reliability, operating crew skills and teamwork, and individual operator concerns are all important and must be considered during application design. A general approach to incorporating operating culture considerations into APC application design is described. A case study for an iron ore concentrator plant is presented.

Jan 1, 2014

By J. D. T. Steyl

"This paper presents a phenomenological model of the rate of iron(III) precipitation in batch and continuous autoclaves at medium temperature operating conditions. The rate expressions are based on information obtained from the literature and experimentation at low and high pulp densities. Special allowance is made for the formation of surface nuclei, which appears to be promoted at a higher iron(III) precipitate surface area, especially in suspensions of lower terminal acidity. This leads to the formation of secondary particulates and provides the required link to simulate high pulp density leaching-precipitation systems, using low pulp density batch precipitation data. In particular, the model allows direct application of the simulation to the autoclave oxidation of iron-containing copper sulfide concentrates and provides a good estimation of the relative precipitation rate of hematite, the preferred product, compared to hydronium jarosite. Some interesting mechanistic understandings of iron(III) precipitation in autoclaves are further elucidated.INTRODUCTIONThe objective of this work is to describe the rate of iron(III) precipitation and the relative amounts of hematite compared to hydronium jarosite precipitation during batch and continuous chalcopyrite oxidation under medium temperature (MT) (~130 to 160ºC) autoclave conditions. Published information has not yet revealed sufficient mechanistic insights about this sparingly soluble salt system under these conditions. The rate expressions in this paper are based in part on current literature information, supplemented by qualitative experimental observation at low pulp density conditions, in particular the high-resolution backscatter electron (BSE) images and particle size distributions (PSDs) of the precipitates. A summary of this work and insights from the literature are presented first, after which the behaviour of iron(III) in high pulp density leaching systems is used to derive a phenomenological expression of the effect of existing iron(III) precipitate surface area on the precipitation rate. The overall regression encapsulates all the experimental results, i.e., those obtained in both batch and continuous autoclave configurations (Steyl, 2012a)."

Jan 1, 2012

By A. O. Dufresne

A Step which, it is believed, will prove extremely beneficial to the Quebec asbestos-mining industry was taken during 1931, when the asbestos mine operators of the Province assembled to work out a uniform method of naming the products of their mines. The outcome of several meetings was the drawing-up of a classification which defined, limited, and designated anew the numerous grades of asbestos marketed. It entailed no drastic departure from the existing processes of grading, nor any revolutionary changes in methods of testing, but aimed rather to perfect existing methods. The classification proposed has been accepted by all operators in the Province, who, from January first of this year, began introducing the new nomenclature. Unless one is conversant with the properties and mode of occurrence of chrysotile asbestos, with the unique milling methods devised for its recovery, and with the history of the development of their technique, he may not readily understand the basis of the new classification. For information on these and other data concerning the industry, the reader is referred to a recent publication, Chrysotile Asbestos in (Canada, by James Gordon Ross, issued by the Mines. Branch of the Department of Mines, Ottawa. The object of this paper is to present briefly some of the phases in the evolution of the classification of Canadian chrysotile asbestos, in the hope that the recent effort to standardize the marketable products of one of Canada's most important non-metallic mineral industries will open a field for discussion, fruitful in new ideas and constructive suggestions. The necessity for the grading of asbestos results fundamentally from the fact that the price per ton depends on the length of fibre. At all times in the history of the industry, the very limited available supply of the longer grades, as well as the requirements of the trade, have caused relatively very high prices to be paid for fibre over half an inch in length, while for the shorter grades the price decreases rapidly, and at a rate which bears no proportionate relation to the length of fibre.

Jan 1, 1932

Arsenic bearing minerals such as enargite (Cu3AsS4) and tennantite (Cu12As4S13), which may associate with major copper minerals such as chalcopyrite (CuFeS2), chalcocite (Cu2S) and bomite (Cu2FeS4), usually report to the copper concentrate in conventional flotation due to their similar flotation properties. Arsenic in a copper concentrate causes environmental problems and also problems in the subsequent pyrometallurgical process. Voltammetric studies were carried out to investigate the oxidation characteristics of enargite, tennantite, chalcopyrite, chalcocite and bomite. Contact angle measurements and micro-flotation tests were conducted to examine the flotation characteristics of enargite and chalcopyrite under controlled pulp potentials. Selective flotation of enargite from chalcopyrite under varied pulp potentials was conducted to investigate the feasibility of arsenic removal from a copper concentrate. The test results indicate that the non-arsenic bearing copper minerals ( chalcopyrite, chalcocite and bornite) were easier to oxidise than arsenic bearing minerals ( enargite and tennantite) in an alkaline solution. Enargite floated well at a potential as high as +0.45 V vs. SCE while chalcopyrite was completely depressed at a potential higher than +0.43 V vs. SCE. Selective flotation revealed that enargite can be successfully removed from chalcopyrite through controlling the pulp potential at +0.30 ~ +0.50 V vs. SCE.

Jan 1, 2007

By P. Hansman

"Place Dome Canada's Detour Lake Mine is a low-grade gold producer located in northeastern Ontario. Production is targeted for 2850 tonnes of ore per day. As reserves and mining areas continued to be found below and far to the west of the shaft (Fig. 1), it became necessary to review and upgrade the materials handling facilities. This paper deals with the selection, design and construction of an underground crusher and conveyor system capable of handling up to 450 tonnes per hour from the lowest existing level in the mine.BackgroundThe Detour Lake mine site is accessed via secondary Highway 652 which runs northeast out of Cochrane, Ontario. The road consists of 200 Ian of hard top followed by 100 Ian of well maintained gravel to the mine site. A 1500 m airstrip is maintained at the mine site for emergency use. Prior to 1991, the workforce was flown to and from the mine site. Crews were now bused to the site from Timmins. Remnants of a winter road exist to the southeast which at one time ended in La Sarre, Quebec. This was the route used to haul bulk items during the construction period and early production years.A town site has not been established at the site for the current operations. Instead, a rotational scheme is being utilized whereby most personnel will work seven days on site followed by seven days off site. For some employees, however, the work week is termed as a four/three schedule where they work 42 hours between Monday at 10:00 a.m. and Thursday at 4:00 p.m. with the following three days off. All surface employees and maintenance employees underground work 12-hour shifts. All underground employees work a lOV2-hour shift. Supervisors work a similar schedule as their crews, however, other staff may overlap their rotation during the week.A five-compartment shaft was sunk in 1984 from surface to the 610 m elevation. Shaft stations were established at the 120 m, 260 m, 360 m, 460 m, and 560 m levels. The cage compartment consists of a single deck, 4O-man cage in balance with a counterweight. The cage hoist is an Ingersoll-Rand 10H and is regulated to travel at 4.1 m/s. Two 9 t skips operate in balance at a travel speed of 7.1 mls. The skip hoist is a 3.05 m drum Nordberg. Both hoists are automated to function without a hoistman during normal skipping and cage service runs."

Jan 1, 1995

By P. Lin, S. G. She

"In June 1985, Chinese Society for Rock Mechanics and Engineering (CSRME) was established. During the past 30 years, various major achievements are made in the discipline of rock mechanics and rock engineering field, especially in the last ten years. This paper will discuss the main rock engineering progress in association with China National Science and Technology Awards, “973 Program”, and “Tan Tjongkie Lecture”. The current status of rock engineering in China and some hot problems are summarized. Furthermore, some suggestions are given for addressing those problems. INTRODUCTIONThe modern concept of rock mechanics and engineering was initiated and developed after the Second World War. In this regard, the International Society for Rock Mechanics (ISRM) was established in 1962, subsequently further promotes its development. In June 1985, the Chinese Society for Rock Mechanics and Engineering was established. Various chief scientists, including professors Tan Tjangkie, Pan Jiazheng, Sun Jun, Wang Sijing, Qian Qihu, have made their huge efforts to the development of Rock Mechanics and Engineering in terms of the large-scale rock engineering projects in China.The achievements in the last 30 years significantly promote the development of China in different fields, such as energy, transportation, national defense and other national economy and major infrastructure facilities (Wang et al. 2004; Qian 2010, 2011). In other words, these projects also promoted the science and technology progress in rock mechanics and engineering across the world. Reviewing and analyses of the experiences on those key rock projects are beneficial to its technological development. She and Dong (2013), in view of literature statistical analysis, discussed the status and research progress in rock mechanics field associated with the last 30-year China's developments, including the rock strength and deformation theory, rock fracture and damage mechanics, the constitutive relation of rock dynamics, rock field coupling, rock reinforcement and stability analysis, etc. The challenging issues in rock mechanics were also proposed, which are the main concerns in rock engineering practices, engineering exploration, design, construction and operation."

Jan 1, 2015

By C. O. Stee

Introduction The property of Siscoe Gold Mines, Limited, is located on an island of three hundred and forty acres in lake Kienawisik, about fifty-two miles east of Noranda and forty-three miles south of Amos, Quebec. Lake Kienawisik is a part of the Harricanaw drainage system and is crossed by the main line of the Canadian National railway at Amos. This waterway is navigable for boats with a draught of six to eight feet. Diesel engines have been the source of power at the property since milling operations were commenced in January, 1929. The power plant as first designed and built was for a milling capacity of 100 tons. Two Polar-Atlas units, each of 200 h. p., comprised the original installation. With the growth of the 'mine, more engines were added until, at the present time, there is installed at the Siscoe what is rated the largest Diesel plant at any mining property in Canada. Definition of a Diesel 'The Diesel engine is an internal combustion engine which works with liquid fuel introduced after, and independently of, the air charge at a time when communication between the cylinder and the outside atmosphere is cut off, and which ignites the fuel by compression-beat and stored combustion-heat unassisted by heat sources outside the cylinder itself while the engine is in stable operating condition"(1).

Jan 1, 1934

By John C. Lyons

"The Wabana iron ore deposits occur as flat-dipping beds of oolitic hematite and chamosite, of Lower Ordovician age, which outcrop for 3 miles along the northwest coast of Bell Island, Conception Bay, Newfound-land, about 16 miles from St. John's.The deposits occur in three zones, Upper, Middle, and Lower beds, separated respectively by 30 feet and 215 feet of shale and sandstone. They are primary sediments laid down in a shallow tidal basin by the precipitating action of a marine environment on iron-rich fresh waters flowing into the basin.The ore-bearing zones, while of wide areal extent, are not uniform beds of hematite that can be mined wholesale. The action of waves and currents during sedimentation; the delta pattern, velocity, and transporting power of streams flowing into the basin; the contours and oscillations of the sea bottom on which the sediments were laid have all been fundamental in the emplacement of richer and thicker mineable sections, and of lean zones so intercalated with shale as to be unmineable.The preservation of the deposits is due to their location in the Conception Bay syncline and to a considerable upthrust of the country east of the bay in post-Ordovician time.The hematite deposits were first recognized as such in 1892, and soon after were acquired by the Nova Scotia Steel and Coal Co. They are now being mined by Dominion Wabana Iron Ore, Limfred, a wholly owned subsidiary of the Dominion Steel and Coal Corporation, Limited. Production started in 1895, and up to the end of 1955 totaled 58,588,516 long tons of hematite ore, having an average dry analysis of about 51 5 per cent iron, 11 8 per cent silica, 0·9 per cent phosphorus, and l ·5 per cent moisture. About 40 per cent of the total tonnage mined has come from surface stripping and on-shore mines. These areas have now been almost completely depleted, and operations are confined to submarine mines extending for two miles off shore under the waters of Conception Bay. Three sub-marine slopes are currently in operation, Nos. 3 and 4 working in the Lower Bed and No. 6 in the Middle Bed. A general picture of the workings is shown in isometric projection in Figure 1. Submarine mining has been entirely by the room-and-pillar method, with an extraction of 60 per cent. The deepest workings, at a vertical depth of 1,850 feet below sea-level, have a rock cover of about 1,500 feet. No mining is done in areas where the rock cover is less than 200 feet. To date mining has explored six square miles of a potential area that may exceed 50 square miles."

Jan 1, 1949

By J. Ita, F. Malekzadeh

"Multi-scale simulation in coupled fluid flow- geomechanical systems is a computationally efficient method for numerically solving large poroelastic systems. When using multi-scale methods, care must be taken in ensuring consistency when information is exchanged between systems that have a different discretization. Here a method is presented which provides consistency between the pore pressure being calculated on a fine scale fluid flow domain and upscaled to the coarser scale geomechanical domain and the pore volume change being calculated on the coarse geomechanical domain and down-scaled to the fine fluid flow domain. Central to this process is the characterization of the mechanical properties of the poroelastic system at both scales.Another advantage of the method presented here is that it is applicable to hydraulically disconnected but laterally drained (i.e. multi-porosity) layered systems as well as hydraulically connected, layered systems. Thus it can be used in geological situations where thin shale streaks or hardpans impede flow between laterally extensive, hydraulically conductive units. This is significant as the pressure evolution of such a hydraulically disconnected, laterally drained system can be very different than a hydraulically connected one as shown here. INTRODUCTIONA multi-scale treatment of fluid flow and deformation is a key enabler when simulation of poroelastic phenomena is limited by computational resources. As the spatial domain of the geomechanics model is usually larger than the fluid flow model, it is desireable to use a coarser discretization in the geomechanical model compared to the fluid-flow model. This type of multi-scale simulation requires a consistent up-scaling of pore pressure from the fine scale fluid flow model to the coarse scale geomechanical model and down-scaling of pore volume change from the geomechanical model to the fluid flow model (see Figure 1)."

Jan 1, 2015