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By C. Arson

We modeled mode I fracture in shale with an equivalent damage zone (CDM), a cohesive zone (CZM) and discontinuous enrichment functions (XFEM). In the Differential Stress Induced Damage model (DSID model) used in the continuum approach the total work input is equal to the sum of the energy released by crack debonding, the energy dissipated by crack opening, and the elastic strain energy stored in the bulk outside of the damage zone. In CZM and XFEM, the overall stiffness of the rock mass in the process zone drops as soon as the fracture starts propagating (unstable fracture propagation), whereas rock elastic properties in the CDM equivalent damage zone evolve smoothly with the displacement imposed at the boundary of the domain. In the CZM and XFEM, fracture propagation stabilizes after a turning point: this point coincides with damage initiation in the DSID model. As a result, the total energy of the rock mass calculated with CDM is about twice as large as in CZM and XFEM. The relative energy components of the rock mass are in the same order of magnitude and follow the same trends in the three models. This numerical study compares the evolution of dissipated energy potentials during mode I fracture propagation, and is expected to provide a basis to predict the amount of energy released by discrete fracture growth vs. damage propagation in the fracture process zone.

Jan 1, 2015

By C. D. Kaeding

IN the summer of 1937, the Algoma Steel Corporation, Limited, decided to embark on the full-scale development o their Helen mine and the erection of plants to produce commercial iron sinter from its ores at a rate ? of fifteen hundred tons per day. The Helen deposit has long been known as one of the largest bodies of non-commercial iron ore in Canada, consisting almost entirely of siderite with a band of pyrite along the north wall and some lenticular inclusions of pyrite throughout the mass. It originally contained a nominal amount of hematite (2,800,000 tons), localized at the western end of the ore-body, but this was mined out during the years 1900 to 1918. For details of the:-geology of the Helen range and of the surrounding district, the reader is referred to Memoir 147, Michipicoten Iron Ranges, Geological Survey of Canada, 1926 (1). The siderite mass was explored by diamond drilling in 1917 and the portion so drilled was estimated to contain 67 million tons of siderite averaging 36.0 per cent Fe, 3.2 per cent S, and 8.2 per cent SiO,, without establishing its ultimate depth or extent. The variation in the sulphur content shown by drilling was from 1.5 per cent in 72 per cent of the tonnage, to 7.2 percent in the remaining 28 percent. The pyritic ore aver-aged about 38 percent iron, but otherwise its composition was substantially the same as that of the siderite mass.

Jan 1, 1940

By M. Hozayen, Q. Ni, E. S. Radwan, P. Nawrocki, A. Jebbouri

"A major geomechanical study was conducted for one of the UAE onshore oil fields with the purpose of studying reservoir rock properties and stress distribution, based on which a 3D coupled reservoir geomechanical model was built. This model was later used for wellbore stability analysis and for analyzing the effect of fractures on future reservoir production performance, including fracture deformation and permeability evolution occurring due to reservoir depletion and resulting changes in local stress field. The subject of this study was a complex fractured Upper Cretaceous carbonate reservoir characterized by high degree of heterogeneity, both vertically and laterally. Wellbore instability related drilling problems were encountered while drilling the wells in this field. The problems were mainly in drilling the horizontal wells, including breakouts and mud losses. Experimental results of laboratory tests used in this study are summarized in Part I of this paper whereas wellbore stability analysis and formulation of a3D geomechanical model that was built for that purpose is summarized herein.A 3D geomechanical reservoir model was developed, which included natural fractures. The mechanical properties of the reservoir rock, such as Young’s modulus, Poisson’s ratio, UCS, friction angle and tensile strength were populated based on the correlations established in Part I of this paper and the developed model was then used to simulate the 3D mechanical-property distribution and the evolution of the in situ stresses in the field due to depletion from 1983 to present-day. Based on the full field model, mud weight cubes were developed to predict the safe mud weight windows in different drilling directions. In addition, well stability prediction for two planned wells was performed using a 3D near-borehole model. Firstly, the computed stress state and mechanical properties simulated in the full field model were extracted along the well trajectory of an existing horizontal well which was drilled recently and then, a3D near-borehole model was constructed along the well trajectory. The wellbore stability analysis along the well trajectory, including stress state, strain distribution and displacements, was performed to identify the instability events along the well trajectory. It has been seen that the presence of natural fractures is closely related to the recorded borehole instability incidents. The computed plastic strains which indicate the wellbore failure were consistent with the recorded wellbore instability events in the FMI image logs, what provide further verification of the developed model. Then, this 3D near-borehole model was applied to two planned horizontal wells and the wellbore stability analysis for the two wells was carried out.The results showed that drilling vertically in the reservoir is safer than drilling horizontally. However, the drilling mud weight window in the vertical direction is narrow, being as narrow as 18.7 pcf or 0.299 sg locally. Drilling horizontally is less stable towards the maximum far field stress direction than towards the minimum far field stress direction. The mud weight cubes were used to identify the optimal well placement and well trajectory. For planned well trajectories, this technology can also be used to determine the optimal mud weight."

Jan 1, 2015

By Andreea Catalina Gluhoi

The oxidation of propylene and methane has been investigated over two series of Au/MOx/Al2O3 and Au/MIOx/MIIOx/Al2O3 catalysts (M, MI, MII =Li, Rb, Mg, Mn, Ce, Zr). Whereas the effect of the presence of MOx or MOI x/MOII x on the oxidation of methane is relatively small, a large enhancement in activity is observed for propylene oxidation. Synergistic effects have been observed by combining ceria or a transition metal oxide (high oxygen storage capacity) with an (earth) alkali metal oxide.

Oct 1, 2003

By J. P. Bennett, K. S. Kwong

Slagging gasifiers are used to produce chemicals and/or electricity from feedstocks such as coal and/or petroleum coke. A gasifier environment includes pressures from 400 to 1000 psi, temperatures from 1250-1550°C, are cyclic, reducing gases of CO and 112, and molten ash that interacts with the refractory liner materials. The high Cr2O3 refractory liners of gasifiers fail within 3 to 24 months. Gasifier users seek materials with increased reliability and service life. This paper discusses causes of refractory failure and efforts to increase refractory service life.

Jan 1, 2004

By J. P. Bennett, W. E. Lee, S. Zhnag, K. S. Kwong

An EAF slag properly saturated in MgO results in increased refractory service life and steelmaking efficiency. A computer model was developed using phase equilibrium data from the MgO-CaO-SiO2-FeO, MgO-CaO-Al2O3-SiO2 and SiO2-CaO-Al2O3-FeO systems to predict MgO saturated slag chemistry. This model has been successfully applied to a commercial EAF, although disciplined plant practices are required to achieve benefits from slag chemistry control.

Jan 1, 2004

By Robert White

?Introduction of BMS?Paste fill generalities?Development through paste?Development through rock fill?Conclusion ?Brunswick mine is operated by Xstrata. The mine has been in operation since 1964 and produces around 10 000 tons per day of ore containing (in order) zinc, lead and silver? The ore body consists of close to ten sub-parallel massive sulfide lenses. The length of the ore body is 1200 m with a width of up to 200 m. From the surface, the ore body extends to a depth to 1200m ?There is 100 km of active drifts for a total 400 km ?The mine is divided by 7 levels and 23 actives sub levels

Feb 1, 2008

By R. S. Jr. Stronach

"IntroductionThe property of Campbell Red Lake Mines, Limited, is in Balmer township, Red Lake area, Patricia portion of Kenora district, Ontario. It consists of a group of twelve claims which had been staked and re-staked a number of times before George W. and Colin A. Campbell staked them in 1944. Messrs. Brewis and White incorporated Campbell Red Lake Mines, Limited, in July, 1944, to acquire these claims from the Campbell brothers, and in November of the same year re-assigned their option on the controlling interest of the treasury shares to the Dome Exploration Company (Quebec), Limited, a wholly owned subsidiary of Dome Mines, Limited.A long known exposure of sulphides on the northeasterly portion of the property, which returned low gold assays, on sampling, was the only showing of interest at this time. However, Dr. H. C. Horwood's report and map of the district had recently been published and favourable structure W3.S indicated in Balmer township. It was on the strength of this showing and Dr. Horwood's report that Dome Exploration became interested in the property.Between. January, 1945, and April, 1946, a diamond drilling programme was carried out, with completion of sixty-one holes. Five holes proved the surface showing to hold no commercial interest, so routine cross-sectioning of the property from north to south was started. The fourth hole of the series returned excellent ore intersections and from that time on the programme changed to one of extending these values. The final results of the drilling showed that what is now known as the A zone has a continuous length of some 1,200 feet, a width of 4½ feet, and an overall grade of about 0.5 oz. gold per ton. There were many other intersections of ore grade outside this A zone which could not be successfully correlated .at that time, but underground work has opened many of them. It may be said here that practically all the work to date has been confined to the southeast claims of the property."

Jan 1, 1950

By Robert A. Brown

"The O'Brien mine is in the west-central part of Cadillac township along the Cadillac 'break', which extends for 7,500 feet from west to east across the property.The ground was staked in 1924 by A. Dumont and W. Hermeston, prospecting for M. J. O'Brien, Limited. The first vein discovered is that now known as No. 1. The No. 4 vein was later exposed on the surface; the other veins known to be present were revealed by underground work and diamond drilling carried out both from the surface and underground.The mine is developed from three vertical shafts: No .. 2 extending from the surface to 2,000 feet; No. 3 from the surface to 1,500 feet; and No. 4 from 2,000 to 3,000 feet. There is on the property a mill of about 200 tons a day capacity, the usual shops, and a townsite housing about forty-five families. Gold production to the end of September, 1944, amounted to 295,824 fine oz. from ore having an average grade of 0.505 oz. a ton. In addition, the mill recovered 3,237 tons of arsenic trioxide having a purity of 83 per cent As2O3.GENERAL GEOLOGYThe four main groups of rocks of the Cadillac area- the Cadillac, Blake River, Kewagama or Pontiac, and Malartic- are found within the boundaries of the property. However, as these rocks have been fully described in · various government reports (1,2,3,4,5,6) and all the known orebodies occur within one group- the Blake River-a detailed description of the geology will be dispensed with here. The known ore deposits lie south of the Cadillac 'break' in a group of rocks that includes 'greenstones', greywackes, conglomerate, porphyries, and a rock of gabbroic composition that may be intrusive. Both flows and tuffs can be recognized in the 'greenstones'. The two bands of porphyry that trend easterly across most of the property have been considered by some observers to be dyke rocks and by others to be flows. Certain evidence points to their being dykes that were intruded as sills considerably prior to the emplacement of the gold-bearing veins, but the possibility of flow origin cannot be fully rejected. North of the talc-chlorite-carbonate schist zone forming the 'break' the rocks are conglomerate and greywacke with iron formation, in which there are no known veins of ore grade. Within the schist zone are minor acid and basic intrusives. The general trend of both bedding and schistosity is a few degrees south of east. The dip is generally vertica1 or steep to the south."

Jan 1, 1954

By Douglas R. Piteau

"Assessing the stability of a slope cut in rock is basically a problem of engineering geology - geology, because it involves a sound understanding of the important aspects of geology, such as geological structure, ground water, weathering and other natural phenomena, which all relate to or exist in a geological environment, and engineering, in that quantitative evaluations and calculations are necessary, these being based on mechanics and relating to the strength of the geological materials and the forces causing instability of the slopes. The engineering geologist must make every attempt to. provide, in a quantitative way, information on those geological factors which are necessary for making calculations of the probable stability of the slope. These include numerical assessments of quantities relating to the characteristics of structural discontinuities, rock types, topography, hydrogeology, tectonic history and other environmental factors. Based on the development and extension of these general principles, both preliminary and final slope stability studies of some open pits in South Africa, Swaziland and Zambia have been conducted. Some of the basic concepts and techniques developed to carry these studies out are described."

Jan 1, 1972

By C. J. Kerr

"A recent information sheet from the Mining Health and Safety Branch of the Ontario Ministry of Labour was sent to all Ministry inspectors and engineers. The subject title was' 'Two Brakes on a Hoist Carrying Persons"" and it quotes mining regulation 699, sub-section 206(i):No hoist shall be used for the transporting of persons unless it has a braking system consisting of at least two sets of mechanical brakes to stop and hold the drum for the shaft conveyance transporting the persons.The intent of the regulation is that each of these brakes is to be set so that, individually, they can safely stop the drum carrying persons and also hold the drum without movement with the maximum manload.This can be achieved in the following ways: Single Drum Hoist-one brake on each side of the drum, one brake on the drum, one brake on the pinion shaft, where disc brakes are used two separate disc brake assemblies on the disc. Double Drum Hoist, brakes on companion drum can serve as backup brake only pinion brake with one drum unclutched.Friction Hoist, one brake on each side of drum As new hoists can be manufactured easily with a two-brake system, attention will be focused on retrofitting pinion brakes to older hoists.A brake mounted on a pinion shaft is designed purely as an emergency brake in the event of main brake failure , controls malfunction, and power loss."

Jan 1, 1989

By J. S. DeLury

Introduction The problems of metallogenesis are largely related to those concerning the origin of igneous rocks, which, in turn, are involved with the question of crustal mechanics. Many ore-bodies are genetically related to associated intrusive and there is an equally close association apparent between igneous intrusion and crustal deformation. The problem of ore-deposition is concerned, therefore, with the fundamental problems of geology. For a long time speculations regarding crustal movements rested largely on the contraction theory and its associated conceptions. Vertical movements were considered to be all important and horizontal movements secondary to them. Magmas were pictured as rising more or less vertically in the crust and were believed to form in vertically disposed magma-chambers or reservoirs. The principle of magmatic differentiation seemed to offer the best explanation of the origin and association of diverse rock types and it seemed also to require the existence of quiescent magma-chambers for the admittedly slow process of differentiation. Accumulating evidence of the importance of horizontal movement in the crust, has, along with other considerations, discredited the contraction hypothesis and many of the inferences that go with it. The same evidence may require some change in the prevailing conception of the origin of the various types of igneous rock and of the mechanics of intrusion. Geologists are now at sea concerning some of the vital and fundamental problems of the crust, and the field is open for speculation. The writer is developing a hypothesis which seems to permit an explanation and? a correlation of earth structures and phenomena. If it rests on a firm foundation, the hypothesis, because it is fundamental, is certain to have a profound bearing on the problems of economic geology. It is for this reason that an outline of the hypothesis is offered at this time. Only a few of its economic bearings are foreseen at this time and these will be indicated.

Jan 1, 1932

By T. Donkin, B. Patterson, M. I. Guthrie, J. T. Ross

"Interest in the use of particle-based ore sorting has increased significantly with recent advances in sorting technologies and higher capacities per unit. Particle-based ore sorting has the potential to provide great value in processing lower grade ores from mines while delivering higher grades to the mill, as well as in upgrading waste rock into ore. Typically the focus is on the amenability of the ore to ore sorting and associated reductions in energy, water, and consumables utilization. However, layout significantly affects the installed cost of a processing plant, and the impacts on layout from fitting an ore sorting circuit into the plant plan need to be carefully considered. This paper examines processing plant layout considerations that play an important role in ore sorting projects, including additional crushing and screening requirements, transport of rejected material back to the waste stockpile (mine fleet requirements), and effects on the processing plant footprint. ¦ KEYWORDS Cold climates, Ore sorting, Plant layout RÉSUMÉ L’intérêt porté à l’utilisation du tri granulométrique du minerai a considérablement augmenté au vu des récents progrès réalisés en matière de technologies de triage et des capacités supérieures par unité. Le tri granulométrique du minerai offre une plus-value intéressante en termes de traitement du minerai à plus faible teneur extrait des mines ; il permet par ailleurs l’acheminement vers le concentrateur de minerai à plus haute teneur et la revalorisation des stériles dans le minerai. On met généralement l’accent sur la susceptibilité du minerai au triage et sur les réductions connexes en termes d’utilisation de l’énergie, de l’eau et de biens consommables. Cependant, l’aménagement physique de l’équipement a une incidence non négligeable sur le coût installé d’une usine de concentration, et les répercussions sur l’aménagement de l’installation d’un circuit de triage du minerai dans l’usine doivent être soigneusement examinées. Cet article étudie les considérations relatives à l’aménagement de l’usine de traitement qui jouent un rôle important dans les projets de triage du minerai, et notamment les exigences supplémentaires en matière de concassage et de criblage, le transport de matériau résiduel jusqu’à la pile de stockage des déchets miniers (nombre de camions requis dans le parc minier) et les effets sur l’empreinte de l’usine de traitement. ¦ MOTS CLÉS aménagement de l’usine, climats froids, triage du mineraiINTRODUCTION Ore sorting has been practised throughout history. An early report by Agricola in 1556 documents how metallic and non-metallic minerals were extracted from rocks by laboriously breaking them with hammers and picks and hand-picking selected material with higher grade (Hoover & Hoover, 1950). The concept has not changed, but sorting technology has evolved significantly over the last 20 years"

Jan 1, 2019

By Z. D’Amico

"IntroductionWE HAVE HEARD quite a lot recently on newer methods -of supporting roof, such as roof bolting or the use of metal props and •booms, but, with the exception of roof bolting, these methods are confined mostly to comparatively low, regular seams and even .bolting cannot be used to hold soft sides. Thus, where a seam of coal has great variations in thickness, or where it is faulty, or where the coal sides must be supported, nothing can wholly take the place of timbering with wood. This paper will deal mainly with the method of timbering such a seam, namely, the No. 3 seam mined by Brazeau Collieries, Limited, at Nordegg, Alberta, where the full height of a thick seam is mined in development. However, a few words on one or two other systems practised in Alberta when, in development work, a thick seam is only partially mined, should be of interest.Examples of Timbering in High SeamsThere .are several methods in use today for dealing with high seams of coal. The most popular is to develop the seam by driving road-ways in the coal by some conventional method, usually recovering the full thickness of the seam on the retreat. The following examples illustrate two variations of this method.In Figure I we have a thick •seam of friable coal, with a good roof, pitching about 30 degrees, which is being mined by taking the upper part of the seam in the development work, leaving the •bench coal in place. Figure 1A shows a section through a room."

Jan 1, 1954

By Fred E. Gray

The mill of Bralorne Mines, Limited, is located on the government highway in the Bridge River mining district of British Columbia, approximately fifty miles northeast of Shalalth, the shipping point on the P.G.E. railway. Prior to 1931, the property now owned by Bralorne Mines, Limited, was operated by Lorne Gold Mines, Limited. During the early operation of the mine, the ore had been treated at various times in one of three small amalgamation mills on the property. With the succession to ownership by the Bralorne Mines, Limited, work was started on construction of a new mill of approximately 100 tons capacity per day. The new mill was put into operation in the month of February, 1932, and since that date has been in continuous operation, milling an average of slightly over 3,000 tons of ore a month. The ore treated in the Bralorne mill is a gold-bearing quartz containing a very small amount of silver. About 75 to 80 per cent of the gold is in the form of free gold, the principal remaining portion being intimately associated with pyrite and arsenopyrite. The gangue rock is quartz, together with varying but relatively small amounts of altered diorite or albitite. In some of the ore, usually the higher grade portions, there is also considerable talc, which forms much slime in grinding. The mill is situated near the portal of the main haulage tunnel and the ore is received directly from the mine ore-trains, which dump on to the grizzly over the coarse-ore bin of the crushing plant. Figure 1 shows the flow-sheet of the mill as it is now being operated. Various changes have been made in the flow-sheet and in the reagents since the commencement of operations, and doubtless minor changes will continue to be made in order to increase the efficiency of the mill. Among the more important changes were those from two-stage to single-stage grinding, and from amalgamation plates to blankets. The change in the crushing was made because too much crushing was done when both primary and secondary mills were employed.

Jan 1, 1933

By R. D. Livingstone

"THE LETHBRIDGE COAL FIELD lies mainly .to the north and west of the city of Lethbridge. Mining carried on in this area for over eighty years until 1965. Before the building of a railway the coal was carried by bullock wagon to Montana for use in smelting, and for a while by river boat to Medicine Hat for railway use. The single, almost flat, worked seam is designated the ""Galt"" seam and is about 1.5 metres thick. It belongs to the Belly River formation and is under cover of 80 to 180 metres of weakly stratified sediments. A complex system of cross faults adds to the mining difficulties. Close timbering required in the entries and rooms reflected in a high timber cost and lower output per man shift. The coal is High Volatile"" C"" bituminous in rank with maximum gross calorific value of 11,200 Btu per pound and with a well defined cleavage. Roof conditions in the field range from very tender and very heavy on the south end of the field and west of the Oldman River to a more stable character to the north. Relatively speaking, the whole field would earn a rather tender rating and definitely so in relation to many U.S. fields. Floor conditions are characterized by a bentonitic type heaving in the south end of the field west of the Oldman river to a more stable situation in the north, which can tolerate shuttle car operation if kept drained. Water problems are minimal, except paralleling the Oldman River, where the seam dips below the river level. While vigilance is necessary to prevent accumulations of gas, the volume is rather limited. The seam was entered by shafts, except where small mines were located along the Oldman river banks and gained access by drifts. The coal seam was developed by driving either 3 or 4 Face entries 2 1/2 metres (8 ft) wide on 18-metre ( 60-ft) centres. Sets of dual butt entries driven at right angles to the Face entries completed development work. Normally rooms up to 8 metres wide were turned off the butt entries on up to 11 - metre centres. These were worked in groups of three to five, depending on the roof conditions, and normally advanced 60 m (200 ft). In some areas rooms had to be abandoned short of their objectives due to roof pressure, heaving floor and intermittent work."

Jan 1, 1985

By J. Fox, K. Kocsis

"Planning for sustainable cooling potential requires protected space to successfully maintain chilled propylene glycol in storage until needed. Stored propylene glycol should be judiciously cared for, safely kept from the ill effects of heat, in order to remain useful for bulk air cooling. Minimizing the chilled temperature of the propylene glycol reservoir tanks means that atmospheric conditions will be monitored closely during the chilling phase. Storage facilities would maintain restricted airflow while minimizing possibilities for heat transfer during the storage phase. Sustainable cooling systems could reduce or eliminate the need for mechanical cooling if installed with favorable conditions. Storing the cooling potential from the winter months is what this new design is all about.INTRODUCTIONIn most subsurface, bulk air-cooling methods, the main source of potential cooling energy comes from cold-water applications. This paper investigates the practical use of harvested, chilled propylene glycol as the source of cooling potential. Propylene glycol is chosen as the cooling storage liquid refrigerant since its chemical make-up is intrinsically safe to fresh water supplies and will not harm underground workers should a leak occur in the closed cooling circuit. Harvesting the cold of winter is a meaningless endeavor without proper thermal planning for the storage of the cooling potential in cold refrigerant.PROPYLENE GLYCOL STORAGE RESERVOIRA new design for a closed refrigerant bulk air cooling system employing propylene glycol as the refrigerant is presented as the main design topic of this paper. Given that a deep and hot mine will need to be considered safe and productive, a cost-effective cooling system is desired in order for the mining operation to be considered sustainable. For underground mines at northern latitudes, cooling applied to fresh air is only required 3 to 4 months of the year. During winter, ambient atmospheric conditions can be harnessed and stored for use at a later time.The basis of this sustainable design uses very cold ambient air that is circulated around galvanized steel refrigerant reservoir tanks. The propylene glycol reservoir tanks are arranged in a concrete walled pit, or tank farm, excavated in bedrock. During the coldest months, the tank farm will be exposed to the open air. As the seasons change the tank farm will be covered with insulation to maintain the maximum cooling potential for use during the warmest months of the year."

Jan 1, 2019

By Donald J. MacNeil

The commercial carbonate industry of Cape Breton Island, Nova Scotia, began about eighty years ago with the opening of the Sydney steel plant. Significant carbonate deposits are confined to the Precambrian George River Grav" and the Mississippian Windsor Group. George River Group carbonates are thought to have formed as part of a stable platformal sequence. They are crystalline and lie within a dominantly quartzitic sequence. Of the four major sites for George River carbonates on the island, the most commercially promising are the dolomite at Kelly Cove and the limestone and dolomite at Glencoe. Kelly Cove dolomite has good potential for metallurgical, agricultural and fettling purposes; reserves approach 13.6 million tonnes. Windsor Group carbonates were deposited as marine sediments in basins formed by pre-Carboniferous fault blocks. Windsor dolomite reserves at Stoney Creek are only fractionally retrievable and hence are of little economic value. The Windsor Group's Irish Cove limestone has been quarried on a large scale since 1964; no undeveloped commercial deposits, however, remain in the group.

Jan 1, 1984

By N. O. Lotter

The connection between mineralogy and metallurgical performance in a plant was recognised long ago (Gaudin, 1939; Petruk, 1976; Petruk and Hughson, 1977; Cabri, 1981; Petruk and Schnaar, 1981; Kinloch, 1982; Peyerl, 1983, Baum et al 1989 for example). The modern toolbox that we now routinely use for flowsheet development took decades to develop (Lotter et al., 2002; Baum and Lotter, 2004; Lotter, 2011 for example). Many workers contributed considerable time and effort to this overall mission of connecting sampling, mineralogy and mineral processing to integrate the flowsheet development activities. Certain key milestones marked this journey, such as Gy’s treatise on the sampling of particulate materials in 1979, which was later added to by François-Bongarçon, Pitard, Minnitt, and Holmes for example. The development of QEM*SEM by Gottlieb et al. of the MLA by Gu et al. constituted a huge leap forward in accuracy and mineral measurement capacity, as well as a reduction in standard errors of mineral characterisation. The advancement of the microprobe to an automated platform made a significant difference to detailed compositional mineralogy. This led to a strong position from which to draw meaningful processing implications from the mineralogical data. Reproducible flotation testing and reliable plant survey material for characterisation was dealt with by, amongst others, High Confidence Flotation Testing ( Lotter, 1995: Runge, 2010, and Bradshaw, 1997); and Statistical Benchmark Surveying (Lotter, 2005), with earlier prototypes which were steadily improved (Lotter, 1994; Restarick, 1976). The sterling work of Napier-Munn in engaging sound statistical methods with mineral processing led to the successful design and use of methods that could identify and quantify small recovery gains in plant scale trials. This history and present capability are reviewed, including leverage into asset management.

Jan 1, 2018

By O. S. Perry, G. H. Charlewood, K. Griffin, S Ogryzlo, H. Hopkins, G. MacIntosh

"The gold mines of Kirkland Lake are in Teck township, Timiskaming district, Ontario, latitude 48°9'N. and longitude 80°3'W., at an elevation of 1,038 feet above sea-level.There are seven contiguous producing mines in a length of 3;1/2 miles along the general east-west strike of the deposits. The seven mines are, in order from west to east, Macassa, Kirkland Lake, Teck-Hughes, Lake Shore, Wright-Hargreaves, Sylvanite, and Toburn.The first discovery of gold in the zone was made by W. H. Wright in 1911 on the east claim of the Wright-Hargreaves property, and the following year the Tough brothers and H. Oakes found gold in what is now the No. 1 vein_ at the Toburn. Production began at the Toburn in 1915, followed by Teck-Hughes in 1917, Lake Shore in 1918, Kirkland Lake Gold in 1919, Wright-Hargreaves in 1921, Sylvanite in 1927, and Macassa in 1933.To the end of 1946, 31,938,350 tons of ore had been milled at the Kirkland Lake mines, from which 16,132,700 oz. gold, having a value of $498,517,600, were recovered. The bullion varies from mine to mine between 800 and 900 fine, the average for all the mines being 853. The average fineness of the native gold is 941.The workings of some of the mines are more than 6,000 feet deep and sinking to depths below 7,000 feet is now in progress.GENERAL GEOLOGYThe regional structural geology of the area in which the mines of Kirkland Lake occur is described in a preceding paper in this volume by J. E. Thomson."

Jan 1, 1954