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By C. A. Jeffrey, K. Pearson

Abstract - The Croft diorite in central England belongs to a suite of Caledonian igneous rocks collectively known as the South Leicestershire diorite complex. Although the intrusions occupy separate outcrops, they are linked at depth to form a single pluton, buried beneath a cover of Triassic sediments (Le Bas, 1972; 1982, Allsop and Arthur, 1983). Both the Caledonian diorites and the overlying sub-Triassic unconformity have been affected by a complex history of alteration and mineralization which can be subdivided into four stages: (1) deuteric effects, caused by the release of volatiles during magmatic cooling; (2) albitization through sodic enrichment; (3) formation of lowtemperature laumontite, analcime and calcite veins with associated wall-rock alteration to prehnite and pumpellyite; and (4) sub-Triassic unconformity-hosted base metal, manganese and palygorskite mineralization. Zeolite mineralization occured some 200 Ma later than the intrusion itself, during post-Triassic times, as indicated by the presence of a single vein of laumontite and microcrystalline calcite which cross-cuts the sub-Triassic unconformity surface and enters the overlying Triassic sediments. Evidence from fluid inclusion work indicates that two fluids were involved in the deposition of the zeolite veins. One fluid was initially of relatively high temperature (~100°C to 320°C) and low salinity (~0.2 to 5.9 wt% NaCl equiv.), and was probably meteoric in origin, whereas the other was of relatively low temperature (~41°C to 165°C) and high salinity (~0.4 to 16.72 wt% NaCl equiv.), and is interpreted to represent a basinal brine. During Triassic rifting, thinning and fracturing of the crust, with the possible rise of associated magmas (Halliday and Mitchell, 1984), could have increased permeability and heat flow, initiating the circulation of hydrothermal fluids. Triassic unconformity-hosted base-metal mineralization in Central England is similar to other Triassic-Jurassic mineralization in Europe (Mitchell and Halliday, 1976).

Jan 1, 1997

By H. Harzer

Statistics Canada record s indicate that in recent years 70 to 80% of the entire Canadian coal production originated from Western Canadian mines, in which about 55 to 65% of the coals are bituminous. Until recently, less than 20% of the latter were extracted by underground methods , the remainder being surface-mined. However, it is estimated that within the foreseeable future up to 80 or 90% will have to be gained by underground techniques. Although Western Canadian coal resources are considerable, they are unfortunately locked in severely distorted, steeply pitching and faulted seams of variable thickness. Consequently, their economic extraction poses serious engineering problems. One possible solution to the problems is to apply hydromechanical methods to underground mining. This is a well-proven method shown to be economically viable under Western Canadian conditions. This paper endeavours to widen the scope of published data on hydraulic coal mining and is based on practical engineering and cost data gathered through contacts with West German designers and operators of hydraulic mines.

Jan 1, 1978

By A. Broussaud

The paper describes the advanced grinding control system implemented at Newmont Ahafo gold mine, Ghana in 2009 and 2010. It shows how the different components of the Advanced Process Control (APC) system cooperate for increasing plant performance. The SABC circuit processes hard rock from different pits mixed with a variable proportion of oxides. The control strategy is designed to address specific disturbances, including start/stops of pebble crushers, unavailability of oxides, changes in rock size distribution resulting from segregation in the stockpile, and changes in ore type and hardness. The system consists of an expert system per se with extensive use of fuzzy logic, supplemented by an online dynamic model of the process used as a soft sensor, a VisioRock? rock size measurement system over SAG mill feed before addition of recycled pebbles, and an AudioMill? system to analyze the SAG mill sound and detect impacts on liners. All these components are embedded in the same OCS© software platform, which, among other benefits, makes it easy to support the entire system remotely. The paper details the physical constraints and the variables that are manipulated. It describes the control strategy and the contribution of each component of the system. It also describes the project implementation and the performance of the system. In addition to a strong involvement and support of management, the very good acceptance of the operators has been facilitated by the remote access system that made it possible to immediately modify the system each time it was needed during the baby sitting phase. The system made it possible to increase gold production significantly through increases in tonnage and recovery thanks to a better control of the grind size through a stabilization of the secondary ball milling circuit and an improvement of the operating conditions of the classifying cyclones.

Jan 1, 2012

By B. K. Ayres

Modern management of uranium mine or mill waste storage facilities (WSFs) often requires that they be remediated or decommissioned with a cover system. In addition to creating a self-sustaining landscape that supports the end land use, cover systems are intended to reduce long-term risks to human and ecological receptors from the stored waste to acceptable levels. The performance and longevity of a cover system will be strongly influenced by the features or shapes of the WSF final landform. Hence, cover systems and landforms must be thought of as an integrated design. Based on the author’s experience, the most important elements of the design process for maximizing the potential of WSF final landforms / cover systems being sustainable over the long term are noted in this manuscript. Several key items that must be considered and addressed during the planning phase of constructing a WSF final landform are also described. Various methods for monitoring performance of a WSF final landform are also reviewed. Key aspects associated with decommissioning a tailings WSF and waste rock pile at the former Cluff Lake uranium mine in northern Saskatchewan are included to illustrate many of the practical insights provided in this paper.

Jan 1, 2020

By D. Harrington

Ventilation of underground workings consists in establishment of such control of air currents that the underground workers may work in safety, with maximum comfort and efficiency, and without impairment of health; and requires that the mine openings may be made subject to such control of air flow as to remove from these workings at ordinary times harmful gases and dusts, and that, at time of emergency, such as fire or explosion, there may be maintained as much or as little air flow as may be desired covering portions of the mine or the mine in its entirety. Control of air flow is the keystone of any ventilating structure, and this very essential feature is obtainable only by the installation of mechanically-operated fans, together with other;. ventilating devices such as doors, over-casts, regulators, etc. Every mine, large or small, coal or metal, should from the outset be equipped with a fan. While much has been written about natural ventilation and many claims made that in specific mines there is sufficient natural air flow, there are few if any mines, coal or metal, where natural ventilation supplies anything like adequately safe or healthful conditions for underground workers even at ordinary times; and at a time of mine fire or explosion, mines depending upon natural ventilation are practically helpless, and certainly are decidedly dangerous to those unfortunates forced to be in them. While ventilation has practically always been deemed an integral part of coal mining, metal mines have rarely paid much, if any, attention to air circulation until forced to do so by occurrence of some untoward condition or accident. Yet metal mines actually have as great need of efficient circulation of air as have coal mines. The coal mine must remove the dangerous explosive gas, methane, also fumes from explosives and, in occasional places, other gases such as carbon dioxide or nitrogen.

Jan 1, 1933

By P. Cheung, J. Gulyas, R. Clary

Over the past 50 years, the use of autoclaves in the metallurgical industry has evolved from final metal recovery (hydrogen reduction) and purification (sulphide precipitate oxidation) to treating whole ores and concentrates. Recent process developments, such as the use of autoclaves for laterite leaching, have necessitated higher temperature and pressure operations, which in turn have seen marked advancements in technology and manufacturing capabilities to keep in step with process demands. This paper will discuss the advances in technology in terms of design, materials and construction of autoclaves and liners, typical dip tube design and geometric layout. This paper will also address specific auxiliary equipment, such as acid and steam injection systems, and components, such as agitator seal systems.

Jan 1, 2004

By W. P. Campbell

Foreword At the outset, it should be stated that this paper does not pretend to present a panacea for the ills that 'frozen' wells are heir to, but rather is an attempt to bring to the attention of those whose special concern it is, a little theory and some facts, which have been brought to light recently, in connection with the problem of 'freezing' as it applies to naphtha-producing wells in the Turner Valley field, and to draw some conclusions that follow from the facts discovered. It should also be stated that the investigation is not to be regarded as in any sense complete, but in progress. Doubtless new facts will be brought to light from time to time which may modify present ideas on the subject, but whether favourable or contrary, these will be welcomed, as the purpose of the Department is to secure as complete information as possible of the factors contributing to 'freezing', since this must be the first step to an intelligent attempt to remedy or prevent its occurrence, if such can be done. It is possible, too, that the cause or causes of freezing may not be the same in all cases, but whether this be so or not will have to be determined later as new information comes to hand. Introduction One of the worries which must constantly confront the operators of gas-naphtha producing wells in Turner Valley-although all, fortunately, have not met with it-is the possibility of the occurrence of what is commonly called 'freezing' (going off production).

Jan 1, 1930

By B. Pewkliang, K. Ehrig, E. Macmillan, M. Smith, V. Liebezeit, Y. Li

The Olympic Dam iron-oxide copper-gold (IOCG) uranium-silver deposit is the largest publicly declared uranium, fifth largest copper and third largest gold resource. Currently, the operation consists of an underground mine and integrated processing plant. Uranium is produced from leaching of flotation tailings and is a co-product to copper cathode with by-product gold and silver bullion. The Olympic Dam geometallurgy team began studying ore from the Southern Mine Area (SMA) in 2006 and soon discovered uranium behaviour was far more variable than the behaviour in the Northern Mine Area, which had been mined from the start of the operation in 1988. The primary objective of Olympic Dam geometallurgy is to develop metallurgical performance predictors that reliably describe the process performance of different ore types and distribute these into the resource block model for use as a fundamental input into mine planning. The nature of the uranium mineralisation (compositionally and texturally complex and highly variable) meant that classic mineralogy techniques alone could not provide the resolution required for prediction of uranium extraction. However, the combination of quantitative mineralogy, results from laboratory-scale leach tests and modelling within the geometallurgy program has enabled prediction of both uranium flotation recovery (via association with sulphides) and uranium leach extraction, including at variable leach conditions. These stope-based predictions have supported trade-off decisions between operating costs and uranium revenue, and have predicted the changing recovery as the mining operations have moved into the Southern Mine Area in recent years.

Jan 1, 2020

By J. A. Bos, Z. Dai, P. Quinn, A. Lee

A flowsheet is being developed for processing Thompson ultramafic low-grade nickel ores. This type of ore is characterized by high content of serpentinized magnesium silicates which generate slimes during comminution. Flotation of this type of ore proves difficult due to problems associated with the slimes. The flowsheet, based on extensive laboratory and miniplant flotation tests, consists of two key components: desliming by hydrocyclones prior to flotation and using soda ash for pH control in flotation. Satisfactory metallurgical results have consistently been achieved in laboratory full circuit simulation and miniplant tests.

Jan 1, 2009

En quoi consistent les études de suivi des effets sur l?environnement (ESEE)? Les ESEE constituent une méthode de suivi scientifique que l?on peut employer pour déterminer la santé des écosystèmes aquatiques (qui peuvent être touchés par l?activité humaine) et l?efficacité des mesures de protection de l?environnement. Les ESEE sont des évaluations scientifiques itératives du poisson, de l?habitat du poisson et des ressources halieutiques. Le programme comporte des phases séquentielles de deux à six ans de suivi, d?interprétation et de compte rendu au cours desquelles la fréquence et le type de suivi dépendent des résultats des études précédentes. Le programme des ESEE pour les mines de métaux est fondé sur un accord conclu à l?unanimité entre les intervenants. Les exigences du programme et les guides techniques connexes ont été élaborés à la suite d?une consultation multilatérale à laquelle ont participé les représentants du secteur privé, du gouvernement et des collectivités. Toutes les mines assujetties au Règlement sur les effluents des mines de métaux (REMM), aux termes de la Loi sur les pê ches, doivent procéder à une ESEE dans le cadre de l?autorisation qu?ils ont reç ue de rejeter des effluents. Le REMM a été enregistré le 6 juin 2002 et publié dans la Partie II de la Gazette du Canada le 19 juin 2002 (SOR/DORS/2002-222).

Nov 1, 2002

By G. E. Cole

"Amongst the mineral products of Canada gold holds the second place in value of yearly output. . . . . .The production of gold has increased steadily during the past six years and has somewhat more than doubled in that time. For the past four years Canada has been third among the gold producing countries of the world, surpassed only by the Union of South Africa, and the United States of America," and now yields somewhat more than 9 per cent of the annual output of the world."-"The Gold Situation in Canada". Bulletin of Development Branch, Canadian Pacific Railway. The history of gold mining in Canada is comparatively modern and does not take one further back than the late 'fifties of the 19th century. If the efforts of the early explorers in Canada were expended in "seeking with equal ardour, proselytes and gold", history fails of any record of their success in the search for the precious metal. As early as 1849 not a few Canadians travelled from the east by land and water to the Californian goldfields. In the then settled part of Canadathe east-people were alive to the value of any mineral discovery; but the west, owing to its remoteness and to there being no ready means of communication, was virtually isolated from the east.

Jan 1, 1927

By C. Hunt, J. Vivas, D. M. Allen

"In this paper we present the results of a combined remote sensing - numerical modelling study to improve our understanding of groundwater seepage in open pit and natural rock slopes, and to investigate the interaction between groundwater, in-situ stress conditions and brittle fracture. The location of seepage is a key element in the characterisation of rock slope stability in open pits and natural slopes; definition of the fracture network geometry and its inter-relationship with seepage, however, remains a challenge in engineering practice. Current techniques used to characterize groundwater seepage locations require direct access to the rock slope for a detailed and exhaustive investigation, and can be severely limited due to access and the limited coverage of the survey methods both with respect to the height and length of the sampled rock slope. Herein, we describe remote sensing methods, which allow the collection of structural and seepage information over a wide spatial area. Remote sensing techniques are shown to have the potential to provide additional insights into the orientation and general connectivity of fractures that may play a major role in the general stability of a rock slope. A preliminary methodology for the use of remote sensing in the characterization of seepage zones in a natural slope through the application of ground-based LiDAR and Infrared Thermography (IRT) is presented.One of the most challenging problems in rock slope engineering is the realistic simulation of fluid flow through fractured and deforming rock slopes. Deformation and the development of brittle fractures can cause significant local changes in the permeability and strength of the rock mass, potentially affecting rock slope performance. Understanding fluid flow through fractured and deforming rock slopes, especially in highly-stressed environments is of great importance for slope stability analysis. Changes in the interconnectivity of fractures during slope failure are an important, yet are relatively unstudied in rock slope engineering. We present the results of hydromechanical UDEC-Trigon rock slope models focussing on the potential role of brittle fracture in rock slope failure, its interaction with groundwater pressures, and the influence of the assumed in-situ stress ratio. Damage intensity parameters are used to characterize damage within different regions of a biplanar slope failure."

Jan 1, 2015

By A. H. Onur, S. Ural

"The Afsin-Elbistan coal deposit with its 3.4 billion metric tons of reserve is the biggest coal basin and one of the most important resources for electrical energy production in Turkey. The coal deposit is located north of Elbistan, Kahramanmaras Province, in southeast Turkey (Fig. 1).The Kislakoy sub-basin of the Afsin-Elbistan basin was selected as the first open cast mine to feed four power station blocks of 340 MW each. The mine is equipped with six identical bucket wheel excavators of the type Sch Rs (2300/5) 32. The annual coal demand of the power station is 18.5 million metric tons. The Elbistan basin encompasses an area of 900 km2, and its centre lies about 1150 m above mean sea level. The sedimentation took place mainly in the upper Pliocene period. The thickness of the coal bed varies from 20 m to 60 m, respectively. The basal part of the coal beds consists of clay, marl and sandy clay. These formations are overlain by gyttja, which may also occur in the form of calcareous ooze, enveloping coal beds. The thickness of the gyttja is up to 35 m (Otto-Gold, 1969). The coal of Afsin-Elbistan is soft coal and the quality has been found to vary considerably throughout the deposit. The thicknesses of the sterile intercalations vary from 0.50 m to 2.2 m and average 1 m in thickness. From the quality control point of view, the coal seam is regarded as upper seam where the gyttja formation occurs as sterile intercalations, and lower seam where the clay formation occurs instead of the gyttja (Fig. 2). The CaO content of upper Kislakoy coal is very high, grinding resistance is low and base to acid ratio of ash, that is, the ratio of acid oxides of metals to base, is greater than one (Ural and Onur, 2001). Contrary to upper Kislakoy coal, CaO content of lower Kislakoy coal is very low, grinding resistance is high and base:acid ratio of ash is smaller than one. Modified Impact Strength Index (MISI) tests are used to determine the grindability of the Elbistan coals (Ural, 1999)."

Jan 1, 2003

By D. H. Stonehouse

Of the f ive Canadian cement producing regions- Atlantic, Quebec, Ontario, Prairie and Pacific-Ontario has the greatest capacity and normally produces the most cement. However, during the last 5 years the greatest activity within the industry in Canada has been in the Prairie and Pacific regions where major capacity increases have taken place. Most Canadian cement companies produce normal Portland, high-earlystrength Portland and sulphate resisting Portland cements. Some companies also manufacture moderate Portland cement, and low-heat-of-hydration Portland cement. Escalating energy costs highlight the need for technology research into more energy-efficient equipment for the energy-intensive cement industry. The industry is well integrated and plants are well situated to support construction in Canada. Expansion into the United States has become common during the past decade.

Jan 1, 1984

By A. Ignatieff

This is the second review of developments in coal mining engineering (see C.I.M .M. Transactions, Vol. LI, 1948, pp. 262- 264) and covers the period from October, 1948, to January, 1950. Mechanization The period under review was characterized by the intensive development of appliances providing for complete mechanization of coal-face operations. A variety of machines are being evolved or have already been placed on the market which embody the principle of 'continuous mining'. This trend can be observed in all coal producing countries. In the United States, two continuous mining machines have been developed for entry and room application and by the end of 1 949 were being used in a number of mines. These are the Joy Continuous Miner in which the coal is ripped from the face by means of multiple cutter chains, and the Jeffrey Colmol employing cutters on rotating arms for chipping the coal from the face. The Joy machine is made in tw6l models, 34-in. and 48-in. high and designed for a range of seam thicknesses from 3-ft. -t-in. to 4-ft. 6-in. and from 4-ft. 6-in. to 8ft., respectively. Some experience has been gained with this machine and accounts of its performance are already appearing in the technical literature. The Jeffrey-Colmol has a more limited range of working height. The first model, 38-in. high, was designed for seams about 4 feet in thick11ess but more recently the 28-in. low model has been placed on the market for seams 2-ft. 6-in, to 3-ft. 4-in. in thickness. Conventional mobile loading machines of the gathering-arm type are continuing to yield high production under suitable conditions, and improvements or modifications of the basic principle are embodied in new machines as, for example, the Jeffrey mobile (conveyor) loader with extensible (gathering-arm) head developed for conveyor mining.

Jan 1, 1950

By J. Forster, C. A. Pickles, Mackowiak. K.

The future development of nickel laterite deposits is crucial with regards to satisfying impending nickel demands. The commercial implementation of new hydro/pyrometallurgical processes in recent years has led to significant improvements in the extraction of nickel from the laterite ores. One potential alternative pyrometallurgical processing route would be to selectively reduce the nickel and produce a concentrate with nickel contents similar to those attainable in the conventional flotation of sulphide ores. However, even bench scale studies have not yet been able to produce a high grade (>15% nickel) concentrate from a low grade laterite ore. The present research involved the microwave vacuum reduction roasting of a nickel laterite ore to yield a high grade concentrate, rich in nickel. Firstly, the effects of temperature and pressure on the nickel grade and recovery were investigated using a thermodynamic model. Secondly, briquettes containing a mixture of charcoal and a low grade silicate nickel laterite ore were reacted in a microwave vacuum system. The experimental variables studied were the input microwave energy, pressure and absorbed microwave power. Thirdly, the ferronickel in the reacted briquette was concentrated by magnetic separation and nickel grades of up to 21% could be achieved.

Jan 1, 2015

By D. E. G. Maschmeyer

The operation of the pilot plant for the S-C Copper Process during 1976 has provided the basic data for the design of a commercial-scale plant. This paper introduces the commercial aspects of the S-C Copper Process through the presentation of a process flow diagram, a schematic flow diagram and basic design parameters for 75,000 tonnes per year (tpy) copper rod production from chalcopyrite concentrate. Basic operating requirements are outlined and a preliminary estimate of operating and capital costs for a Western Canadian location are summarized. The results have been compared with a modern smelter/electrorefinery to highlight the advantages and disadvantages of these two alternatives and to show why the new S-C Copper Process technology should be of interest to the copper industry.

Jan 1, 1978

By W. M. Tupper

Municipal governments recognize the importance of aggregates in the local economy and the need to manage this resource in the interest of the public good. They have encountered problems with regulating the industry and the dichotomy between the urban need and the rural source. They have suffered from a lack of financial benefit, an adequate aggregate inventory, provincial strategy, economic information and public understanding. A provincial strategy for ensuring the availability of aggregate supplies to developing areas of the Province is essential. The Province should also be responsible for licensing, research, technical expertise on rehabilitation, public education and financial assistance. Upper-tier municipalities (regions or counties) should assume responsibility for resource management, including resource availability, demand characteristics, truck routing, phasing of resource development and sequential land-use planning. Area municipalities (towns and townships) can best determine the social and environmental impact of a specific aggregate development proposal and should therefore have the primary responsibility for the location of new pits and quarries. They should also have the authority to supplement provincial regulations concerning operating standards and the phasing and standards of site rehabilitation.

Jan 1, 1978

By A. D. Hunt

THIS PAPER will review Canada's fossil fuel situation as we understand it today and indicate some of the options available to meet our energy requirements during the next 15 years. It would therefore be helpful to examine Canada's total energy requirements and discuss the un certainties of the data base on which we must base future energy investment decisions. On the world scene, Canada is at the top of the energy-consuming nations, using about 49 bbls of oil equivalent per caput/ year. This appears to be slightly ahead of the U.S. and of course much higher than that of many countries. It is generally accepted that there is a more or less direct relationship between energy consumption and material standard of living. However , as we know, Canada, when compared with other industrialized countries on a GNP, an individual-income or some other standard basis, is lower in the list. This situation may be explained by our more severe climate and a relatively small population distributed over a land mass second only to that of the Soviet Union.

Jan 1, 1977

By W. H. MacLean, S. Liaghat

Abstract- The Key Tuffite is a thick (0.3 m to 6 m) and laterally extensive (-10 km) cherty, sulfide-bearing tuff unit in Archean greenstones in the Matagami mining district in northwestern Quebec. It lies at the contact of the Watson Lake Group and overlying Wabassee Group volcanic rocks, and is host to major Zn-Cu volcanogenic massive sulfide deposits. The tuff component is highly altered and its volcanic precursors are not identifiable by petrographie means. The tuff is mixed with a volcanic exhalative component comprising chert, carbonate and sulfides (pyrite, pyrrhotite, and minor sphalerite and chalcopyrite). The normative mineral composition of the Key Tuffite is 33% quartz, 28% sulfides, 16% sericite, 8% carbonate, 60Jo chlorite and 9% other minerals. In the vicinity of the Bell Allard and Orchan mines, the precursor tuff components are identified using immobile major and trace elements, as Watson Lake tholeiitic rhyolite (Zr/Y = 1.5 to 3.5, LaN/Ybn. = 1.7 to 2.8, Si02 = 72.5 ± 1.2 wt %, and Wabassee calc-alkaline andesite (Zr/Y =9, LaN/Ybn. = 4 to 8, Si02 = 56% to 65%). Immobile element computation techniques were used to calculate mass additions and losses in the conversion of the tuff to the Key Tuffite. Average net amounts of Fep3 (27% total iron), Si02 (14%), CaO (8%), S and K20 ( + 2%), were added, Na2O was removed (-2.8%), and MgO was over-all unchanged. Total net mass change was +63%, which comprises mainly exhalative additions, but also includes changes owing to hydrothermal alteration of the tuff component.

Jan 1, 1992