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By F. Kapeller, G. Herget

"The need for monitoring the effect of changes in ground stresses due to mining in hard rock has existed for many years. The Mining Research Laboratories of CANMET, EMR have developed a new tool which monitors with high precision the radial deformation in boreholes. The result is the Mining Research Laboratories strain monitoring system (MSMS) which uses the highly stable and very sensitive vibrating wire principle to monitor deformations in relatively large boreholes, e.g. 76 mm to 153 mm diameter.The vibrating wire is strung across a relatively large proving ring and operates at a frequency between 600 to 1800 Hz. The read-out system is based on continuous vibration.The ring is installed with a hydraulic tool and brought into contact with the surrounding rock through precisely machined and guided wedges. The resolution of the system is in the neighbourhood of 4 x 10-4 min/ Hz. The data collection can be carried out with a portable read-out unit and provisions are available for automatic data collection. Stresses may be calculated from strain readings.The system was tested in cooperation with the Centre de recherches minérales at the Niobec Mine in Quebec for the purpose of monitoring the effects of drill drift development and slope mining on surrounding ground stresses.After access was available to the site, 153 mm diameter holes were drilled for the determination of in situ ground stresses. These holes were then used to install the strain monitoring system. The effect of drill drift development and production blasting in stopes C-203-13 and C-203-15 on ground stress distribution could be observed clearly.The horizontal relaxation in the core of a pillar which occurred during mining of adjacent rooms was between 0.082 mm to 0.111 mm. Calculations of stresses from these deformations indicate that the rock material is still in an elastic condition.Roctest of Montreal has obtained a license on the manufacturing and distribution rights. A patent has been registered and CANMET will assist in installation of the MRL strain monitoring system and the interpretation of records."

Jan 1, 1989

By G. Ergin

The interactions taking place between Al-Mg alloys and the bed media during aluminum filtration are not yet well understood. These interactions were studied using the infiltration technique. The reaction interface was analyzed using different techniques such as SEM and TEM. Only spinel formation was observed at the interface regardless of the type of alumina and contact time. This paper discusses the results of the study.

Jan 1, 2004

By Philip Thwaites

"Automatic flotation control in varying degrees of sophistication is practiced at a number of concentrators throughout the world. Practically, the variable conditions in the flotation circuit and the difficulty in maintaining accurate instrumentation information all add to the complexity of automatic control.Further development at the Kidd Creek concentrator has resulted in a 3075 mtpd copper flotation circuit capable of running twenty-four hours a day under the direct control of an optimizing supervisory computer.Three main streams, continuously monitored by an XRF analyzer, supply circuit information to the optimizing computer. Circuit efficiency calculations (from smelter contract terms) and target setpoints allow the computer to determine the economic optimum direction to move the circuit based on the grade/recovery relationship. Circuit manipulation is accomplished by precise pumping of collector and frother reagents together with accurate control of flotation bank pulp levels. The former uses computer controlled diaphragm pumps and the latter is achieved by control loops utilizing a float type level transmitter, variable position dart plugs and a process computer working to setpoints determined by the optimizing computer.The development of a fully automated flotation circuit is by no means complete, but increased knowledge and major hardware improvements have allowed its progression to a higher level of sophistication.IntroductionThe Kidd Creek concentrator is located twenty-six kilometers east of Timmins, Ontario, within a metallurgical complex including a 109,000 mtpy zinc plant and a 59,000 mtpy copper smelter and refinery. The concentrator treats two ore types, a copper-zinc ore and a copper-silver-Iead-zinc ore, at a combined rate of 4,500,000 mtpy. Flotation of the crushed and ground ore yields copper and zinc concentrates from the copper-zinc ore and copper, lead and zinc concentrates from the copper-silver-lead-zinc ore."

Jan 1, 1983

By A. A. Ruitenberg, C. J. Morrissy

"The Lake George antimony deposit comprises a system of stibnite-bearing quartz veins that cut Silurian greywacke and slate. The stibnite-bearing ore zone is in part enveloped by a uraniferous zone.The ore-bearing quartz vein system occupies an easterly striking, gently north-dipping fracture system that cuts across north-northeasterly trending gently southwest-plunging, tight Acadian (early Middle Devonian) folds. This vein system continues at depth into a siliceous skarn zone intruded by altered granite porphyry dykes, which constitute probably a late phase of the Hawkshaw granitoid intrusion to the north.Most of the ore occurs in a northeast-plunging, trough shaped vein structure that formed where the vein system (gently north-dipping) intersects the axial surf ace zone (steeply northwest-dipping) of an Acadian synform. The trough shaped structure resulted from deflection of the fracture zone (containing the vein system) by competent beds.Emplacement of the quartz-stibnite veins was preceded by, and is in part penecontemporaneous with, the formation ofa micaceous-argillaceous alteration halo, which in turn intersects a patchy biotite alteration zone.The hypabyssal intrusions associated with the Lake George deposit probably represent a late phase (early Carboniferousr) of the nearby Hawkshaw intrusive granitoid complex. IntroductionThe Lake George Antimony Mine is situated 40 km southwest of Fredericton and 2.5 kin north of Lake George, New Brunswick (Fig. 1). The mine is owned by Consolidated Durham Mines and Resources Ltd.Shaw (1940) described the early history and development of the mine. In subsequent years, available drill cores were relogged by several geologists. Much new information became available when an extensive diamond drilling program (Kidd , 1970) was started by Consolidated Durham Mines and Resources Ltd. in 1970. A study of the geology and economic potential of the deposit was made by Glover (1973). Abbott and Watson (1975) made a study of the ore mineralogy. Available drill cores were relogged and a preliminary study of the fracture system in the mine was made by G.A. Pierce and A.A. Ruitenberg during 1976. Outcrops in the area sur rounding the mine are extremely sparse.Between 1976 and 1979 the present authors made a detailed study of the mine workings, available drill core and regional structure in the vicinity of the mine, with results set forth in this paper. The regional geologic setting of the deposit, the geometry and structural controls of the ore zones, and the mineral zonation and rock alteration are emphasized."

Jan 1, 1980

By Robert B. Parsons

"The tax reform process marches on. The December 16, 1987 measures tabled by Finance Minister Michael Wilson represent one more step toward the objective of total reform of Canada's income and sales taxes. While the income tax changes are taking shape, much work still needs to be done on the sales tax side of the coin.IntroductionOn December 16, 1987 Finance Minister Michael Wilson tabled measures to implement the changes to Canada's income tax system that were proposed in the June 18, 1987 White Paper on Tax Reform. The measures were set out in a Notice of Ways and Means Motion; draft legislation relating to preferred shares, research and development expenditures; and draft regulations regarding capital cost allowance, certified films, flow-through shares, and the resource sector. The reaction of the government to the recommendations made by the Finance and Economic Affairs Committee Report on Tax Reform (the Blenkarn Committee), the Report of the Standing Senate Committee on Banking, Trade and Commerce and through consultations with interested groups and organizations, business, labour and individual Canadians is set out in a booklet of supplementary information.The basic features of the reformed income tax system set out in the White Paper remain. However, a number of significant changes have been incorporated in the Notice of Ways and Means Motion and other material. The following comments address those area s where changes have been made to the original White Paper proposals."

Jan 1, 1988

By Walter I. Nelson

THE geology of the Copper Mountain mine has been ably described by Dr. Victor Dolmage in Memoir 171 of the Geological Survey. Reference is invited to that paper for a more extended description of the geology of the ore deposits than will be given here. The important orebodies of the mine occur in fragmencal volcanic rocks, parallel with and adjacent to the gabbro of the Copper Mountain stock. In the mine area, the contact strikes N.45°W. and dips either vertical or steeply co the southwest. For a distance of 500 feet or more from the contact, the fragmental rocks have been intensely metamorphosed both dynamically and hydrothermally. The dynamic effects are reflected in the foliation and fracturing parallel with the contact, which occurs throughout the mine, and the volcanic rocks within this foliated zone are, in places, highly schistose. Superimposed upon thi.s structure is a system of fine, straight, parallel frac-tures that strike nearly normal to the foliation (and contact) and dip between 65° and 75° to the north; it is with this last-described fracture system that the ore minerals are structurally associated. The fractures are mineralized with bornite and, to a considerably less extent, with chalcopyrite and some pyrite. A notable characteristic is the extreme fineness of the fractures; even in high-grade ore they are rarely larger than pencil lines. The tenor of the ore, therefore, varies directly with the fracture spacing. Replacemcnr of the host-rock between two or more fractures, varying in degree from finely disseminated sulphides to masses of nearly solid bornite up to 18 inches wide and 2 to 3 feet long, is not uncommon in the higher-grade portions of the orebodies. Two structural types of orebody are recognized in local nomenclature: the 'contact' orebodies, so-called because they occur along the contact; and 'outlying' orebodics, which are enclosed in the volcanics. The former arc tabular or lenticular bodies elongated along the strike and dip of the contact. The 'outlying' orebodies are coniform, chimney-like masses roughly elliptical in plan; with depth, their roots plunge at steep angles toward the contact. All of the orebodies are cut by a number of light-coloured granophyre and felsite porphyry dykes. These dykes-the so-called 'mine' dykes -enter the mine area from the north, curve gently southeasterly across the orebodies, and then cross the contact into the gabbro at the south end of the mine. All the dykes dip vertical to steeply east.

Jan 1, 1941

By Barry James

"This paper discusses past and current energy use patterns in the mining and manufacturing sectors of the industrial minerals industry. Information is presented on the primary energy input types as purchased by the industry, the quality and form of the energy actually required by the various production processes, and the residual form of this energy, either embodied in the product or rejected in gaseous and liquid waste heat streams. With the continuing concerns about the availability of energy combined with the rapidly increasing cost of energy as a production input, the reduction of energy usage through improved efficiency will undoubtedly be an increasing priority for the industry during the 1980s. Reduced energy consumption through investment to improve energy efficiency appears to be advantageous from both the corporate and national perspectives.IntroductionEnergy, like labour and materials, is one of the basic production input s to the various mining, processing and manufacturing production stages in the industrial minerals industry. Energy costs, as a percentage of total production costs, have been well above the average for industry in Canada, accounting for more than 50 cents out of every dollar in the most extreme cases. Consequently, energy has always been a relatively important management concern in the industrial minerals industry.The energy supply and price situation in Canada and internationally has been changing rapidly since 1973, following a long period characterized by declining real energy prices and an abundance and wide choice of energy supplies. It is generally accepted that energy prices will continue to increase rapidly, and that there will be uncertainties about the long-term continuity of supply of some energy types. In essence, a period of relative stability has been replaced by a period of relative uncertainty. In such a changing situation, a reassessment of the role of energy as a production input is appropriate.The following sections outline some of the effects of the changing energy scene on the industrial minerals industry. These effects are dealt with primarily in terms of energy costs, because, in most circumstances, a change in the cost of energy as a production input is the end result of both energy price and energy supply changes."

Jan 1, 1981

By J. C. Botham, T. D. Brown

"Coke is the most costly item in steelmaking via blast furnaces . Recent innovations in cokemaking have been directed toward reducing this cost while simultaneously improving coke quality and expanding the range of coals used in the process. It is also important to meet increasingly stringent environmental legislation.Improvements in coke quality have been achieved by novel blend selection procedures, by charge density control using both selective pulverization and partial briquetting, and by the use of modifying additives.The Canadian Carbonization Research Association provides a focus for Canadian cokemakin g research which has demonstrated these technologies in a series of pilot-scale experiments."

Jan 1, 1980

By C. Beaudry

Outline ? General Geology of Frieda River Project Area ? Exploration History ? Geology of Porphyry Deposits ? Porphyry Resource ? Update of Nena Deposit and High-Sulfidation Mineralization ? Nena Resource

May 1, 2006

By J. C. Farge, G. G. Jacox

"The effect of composition and process variables on the properties of Marmet and modified Ni-Hard slugs will be discussed. The effect of shape on the over-all performance of grinding media and its relationship to the end product has been investigated and these results will be reviewed. The cost effectiveness of slugs versus balls has been well documented under various operating conditions and this will be presented in detail. IntroductionThe selection of grinding media is based on the cost-to-wear ratio combined with the consideration that it must stand repeated impacts without breaking. The specific consumption of grinding balls and slugs depend s primarily on their microstructure, which, in turn, is controlled by chemical composition and by the processing condition s to which they are subjected during manufacture.The first part of the paper deals with the optimization of alloy content to produce cast iron slugs with microstructures consisting essentially of marten site and carbide and with hardnesses of 650 B.H.N. and higher. The second part deals with the use of cast iron slugs to replace forged steel balls in milling operations. Tests indicate that the shape of the media has little if any effect on results and that the hardness and microstructure of grinding media will determine its relative performance. Where price is equal under similar milling conditions, the cost effectiveness of cast iron slugs is superior to that of forged steel balls.In order to understand the role of alloying elements in cast irons, it is judicious to consider the microstructural changes which occur during solidification and subsequent cooling, particularly from above the eutectoid temperature. Solidification starts with the formation and growth of dendrites of austenite. As temperature decreases, an eutectic nucleates and grows between the primary austenite dendrites. Immediately after solidification, the structure consists of proeutectic austenite and of the eutectic of primary carbides and austenite. On cooling to room temperature, austenite can be retained or transformed to pearlite, bainite, martensite or mixtures thereof. It is necessary to prevent decomposition of austenite into pearlite by adjusting the alloy content. For best abrasion resistance, the microstructure at room temperature should consist essentially of martensite and carbide. These types of irons are known as ""martensitic irons "". Depending on the carbon content of the austenite and cooling rate, "" as-cast"" martensitic irons will contain different proportions of martensite and retained austenite. The more carbon in solution in the austenite, the lower is the temperature at which the martensitic transfoemation takes place. By the time room temperature is reached ., the transformation is seldom complete, and the end product is generally a mixture of martensite and retained austenite."

Jan 1, 1980

By T. H. Patching, M. W. Mikhail

"Data from a standardized procedure for measuring methane desorption rates from samples of Western Canadian coals gave a good correlation (0.994) with the percentage of fines (-0.6 mm) found in the corresponding run-of-mine coal. The correlation was independent of the mining method and the top size of the samples. It is suggested that both methane desorption rate and the production of fine coal sizes are functions of the fissuration of the coal being mined.This relationship, in conjunction with established data of degradation by unit process equipment, may be useful in predicting the amount of fines that will be produced from new seams of coal and by planned new washeries. It also could be a valuable guide in modifying existing washery processes to minimize production of fines."

Jan 1, 1980

By Robert B. Parsons

"Although the April 19, 1983 federal budget appears to put greater emphasis on new or expanded government spending programs in an effort to get Canadians working again, the budget proposals contain a light sprinkling of tax changes which could be of some direct benefit to the mining industry.This month, Tax Notes examines some of the more important of these changes.IntroductionSome sectors of Canada's mining industry could benefit from the proposed income tax changes announced by Finance Minister Lalonde in delivering his budget address to the House of Commons on April 19, 1983. Improved depletion allowance rules, expanded investment tax credits, better use of business losses, and inflation proofing of personal capital gains on Canadian common shares are all part of the measures included in Mr. Lalonde's first budget to try to reinvigorate the battered Canadian economy.Improved DepletionUnder the Income Tax Regulations, a taxpayer who incurs Canadian exploration expense (and certain other eligible expenses) is permitted to deduct not only the full amount of the Canadian exploration expense (""CEE""), but also an additional allowance (the so-called earned depletion allowance) equal to one-third of the CEE. Thus, a taxpayer in certain circumstances can claim a deduction of $1.33 for each $1.00 of eligible expenditure, including CEE.Although CEE can be deducted from any source of the taxpayer's income (for example, from investment income, salary income, and so on), prior to budget date the earned depletion allowance was deductible only from the taxpayer's resource profits. This restriction on the deductibility of the earned depletion allowance substantially reduced the attraction of the allowance: few individual investors or investment companies, for example, have the required stream of resource profits, at least when the CEE or other eligible expenditure is made."

Jan 1, 1983

By I. M. Masters

Iron removal and control in processes employing pressure leaching technologies developed at Dynatec Corporation are reviewed. Discussions are focused on recent developments in the processing of nickel-copper matte and copper concentrates, and on the Ambatovy laterite project in Madagascar. Iron control and its implications on flowsheet design in the pressure acid leaching (PAL) treatment of laterite ores and in the oxidative pressure leaching of mixed nickel-cobalt sulphide intermediates are also discussed.

Jan 1, 2006

By Rodney Allen

Background: Development of the Project ?European GEODE collaboration 1999: considers possible projects, including a VMS project, to continue after GEODE ?GEODE-CODES-Canada collaboration 1999: Questionaire, database ?Workshop at CODES 2000: project theme and strategy selected ?GEORANGE (Sweden-EU) 2001 supports development of Global VMS Project: interest from 12 nations ?Skellefte VMS Project set up as Sweden?s component of Global VMS, 2002; other projects in Spain, Canada collaborate ?Low metal prices ---> little funding from mining industry 2001-2003, change in strategy ?IGCP/UNESCO support 2004: enlargement to over 20 nations

Apr 1, 2005

By C. Mills, A. O. Burt

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

Jan 1, 1985

By A. O. Orumwense

Mill circumferential speed, the number of passes of pulp through the grinding chamber, media type, size and filling ratio were investigated in an attempt to determine how to effectively grind copper concentrates in a stirred mill. The stirred mill product fineness was enhanced to some extent by decreasing media size, high media filling, and an increased number of passes of the pulp through the grinding chamber. Shape also plays a major role in grinding media effectiveness, with spherically shaped media producing a finer size. The fineness of the product increases with increasing power consumption but the method of energy transfer is very important in energy utilization. The effect of the mill parameters on copper flotation was evaluated. Copper recovery was influenced by grinding media size, mill speed and the number of pulp passes through the grinding chamber.

Jan 1, 2006

By W. Curlook, V. G. Papangelakis, M. Baghalha

A pressure acid leaching process has been developed for the extraction of metal values, nickel, copper, cobalt and zinc, from base metal smelter slags. The basic concept contemplates cooling the smelter slags through solidification sufficiently slowly to induce a good measure of crystallization; and subsequently, after fine grinding, to pressure leach such slags at around 250°C while applying oxygen overpressure, utilizing smelter byproduct sulphuric acid. High levels of extraction of the slags' metal values are thereby achieved. It has been shown that if the same slags are quenched thereby producing an amorphous structure, the resulting metal extractions are very low. The process is applicable to smelting furnace throwaway/discard/dump slags, as well as to in-process converter slags. By extracting the bulk of the residual base metal values in the throwaway/discard/dump slags, the resulting leached residues are rendered virtually benign vis-à-vis the external environment.

Jan 1, 2004

By Nigel J. Cook

"Detailed mineralogical examination of gold-bearing rocks, ores, concentrates and other samples should be considered an integral part of any study of a deposit for which exploitation is being planned. Adequate mineralogical study, although time consuming and often costly, can significantly improve understanding of the mineralization, can help to optimize the results of any metallurgical testing and can be of great value in case of potential trouble-shooting. The advantages and disadvantages of various examination techniques are discussed with reference to a number oj mineralogical studies oj Canadian gold-bearing samples.IntroductionVarious authors, notably Gasparrini (1983), Harris (1989) and Henley (1990), have stressed that mineralogical study of gold ores is critical to successful and efficient beneficiation. Only in cases where diagnostic cyanide leach testing is successful can detailed mineralogical examination be disregarded. Such examination of gold-bearing rocks and metallurgical products is all too often neglected because the methods involved are believed to be time-consuming, costly, and may carry a considerable degree of inaccuracy. Commonly, bulk metallurgical testing is, carried out without prior or concurrent mineralogical examination, causing the results of the testwork to be difficult to interpret, or in some cases, misleading. This, in turn, may lead to> significant delays to the project at the feasibility stage or mean that understanding of the sample is limited, preventing the introduction of prudent modifications at a later stage if problems arise. Mineralogical studies may guide the successful implementation of a metallurgical test program."

Jan 1, 1990

By D. Mills, W. H. S. Lawson

"The need to make repairs is seldom a major consideration in the design, fabrication and installation of major components of electrical generation plants. Repair welding, however, is a fact of life in the electrical generation industry, for restoration of degradation in service, from cavitation of hydraulic turbine runners, to corrosion and fatigue damage in pressure vessels. In making weld repairs to carbon and low-alloy steels, the largest source of trouble is hydrogen embrittlement and related post-weld cracking. Various strategies have been developed to control problems from this source, including post-weld heat treatment, the use of nickel-base alloy filler metals and the temper bead welding technique. Each of these basic strategies is being applied as circumstances require; each strategy must, however, be implemented in a manner that reconciles weldment structure and hardness, degree of restraint and service environment with the consequences of unsatisfactory performance of the repaired component.IntroductionMajor working components of electric generating plants are specified and installed on the basis that, wherever technically and economically feasible, they will retain functional capacity without major repairs for the twenty-five-plus years of normal plant lifetime. Nevertheless, repairs are often required, and welding is usually an essential feature of the work. Remedial welding may be performed to correct design or fabrication errors which become evident only at the time of component installation. The most common causes of requirements for repair involve corrosion, fatigue or related processes which prove more aggressive than expected during service. Increasingly, our planning for future repair requirements is related to continual improvements which are occurring in nondestructive evaluation technology. As components are periodically reinspected during their service life, fabrication induced defects may be revealed for the first time quite late in the life of the component. When this occurs, repair must be considered wherever inaccessibility of a flaw makes it impossible to prove its inactivity. Finally, there are certain components, for instance in hydraulic turbines, which cannot be economically made or used without the expectation of service induced wear. Here, periodic maintenance welding must be regarded as a normal event."

Jan 1, 1981

By J. W. Matousek

"More copper concentrates are treated in flash smelting furnaces than by any other process, and such furnaces are located in most of the world's major copper producing areas. Except for perhaps two furnaces treating chalcocite-type materials, little difference is seen between the grades of the concentrates being smelted. Within individual smelters, even less variation in feed grades is found. This is both accidental and intended. Many furnaces treat concentrates from captive ores, and these tend to be of relatively constant composition over long periods. Toll smelting operations blend concentrates to ensure delivery of feeds of fixed compositions to their furnaces to avoid upset conditions. Matte grades vary between flash smelting furnaces, but most commonly, these are the result of differences in operating practices rather than because of differences in concentrate grades. This paper reviews an industrial flash smelting test in which the copper content of the furnace feed was intentionally altered over a wide range. IntroductionExcept in a few copper mining regions of the world, the principal copper mineral is chalcopyrite (CuFeSz). This results in the almost universal production of concentrates containing 25070 to 30% copper (and similar amounts of iron and sulphur). Many operators of copper flash furnaces spend their entire metallurgical careers smelting concentrates of essentially fixed grades. This is true both of smelters treating concentrates from captive mines and those processing concentrates on a toll basis. From the production staff's point-of-view, the less variation in grades seen by the furnace, the better. Fixed analyses of concentrates and constant feed rates produce consistent quantities of matte at a consistent grade for processing by the converters. The result is, even in smelters treating a variety of concentrates, efforts are expended in sampling and blending to ensure feeds of relatively uniform compositions being sent to the furnaces."

Jan 1, 1993