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By F. P. Hassani, Jacque Ouellet, M. Hossein

A laboratory investigation was undertaken to evaluate the effectiveness of different binding agents in a paste backfilling operation suitable to be used in a sulphide-rich environment. Different combinations of Portland cement and fly ash type C as well as ferrous slag were used as the binding agents. The unconfined compressive strength of the samples was measured for extended curing periods. The results indicate that the addition of 3% slag in the binding agent mix could produce strengths up to 0.5 MPa in the samples under investigation. For higher binding contents, the addition of Portland cement will lead to higher availability of calcium hydroxide and calcium aluminate, which are susceptible to deterioration from the phenomenon known as sulphate attack. Using slag, on the other hand, will reduce the permeability, availability of calcium hydroxide, and dilute the calcium aluminate ions reducing the susceptibility of the samples to sulphate attack. However, gypsum will form which could have the same detrimental effect on the strength of the treated matrix. Therefore, special attention must be given to the content and properties of agents used to activate the pozzolanic properties of the slag.

Jan 1, 2001

By Michel Dagbert, Mohammed Harfi

"Abstract - The Draa Sfar polymetallic deposit, at about 16 km NW of Marrakech in Morocco, is a massive sulfide zone at the contact between an underlying volcanic and an overlying clastics sequence. The mineralized body is a flat lens with schistosity and "boudinage," tilted to the west and with a strong dip to the east. The lens extends over a strike length of about 2 km and from surface to a depth of about 1 km, with thickness varying from 1 m to almost 30 m. It has been intersected by about one hundred surface drill holes and, in its south part, by about thirty underground fan holes from two exploration levels at depths of 300 m and 400 m. On these two levels, the massive sulfide zone has been channel sampled over a cumulative length of about 0.7 km. Results from drill and channel samples are used to estimate the resources of the orebody according to several methods: sections, polygons around intercepts on a longitudinal plan, grids on the same longitudinal plan with various distance weighting methods including kriging and, finally, a 3D grid with the same range of interpolators. A comparison of the various estimates delineates the important factors in deriving resources for this type of deposit. Those factors are mostly geological and related to the interpretation of the geometry of the two limiting surfaces of the zone. For the 3D gridding, the authors have devised a new and original method that constrains the interpolation of blocks from samples to a geometry of limiting surfaces. The resulting model shows internal grade variations that parallel fluctuations of zone thickness and orientation without having to re-orientate the search window in each block. Résumé - Le gisement polymétallique de Draa Sfar, situé à environ 16 km au NW de Marrakech est un horizon de sulfure massif au contact d’une formation volcano-sédimentaire de base et d’une formation détritique sur-jacente. Le corps minéralisé se présente sous forme d’une méga-lentille aplatie, schistosée, boudinée et déversée vers l’ouest avec un fort pendage vers l’est s’étendant sur une longueur de 2 km et une profondeur de près de 1 km avec une épaisseur variant de moins d’un mètre à près de 30 m. Il a été reconnu par plus d’une centaine de sondages de surface et, dans sa partie sud, par une trentaine de trous souterrains en éventail à partir de deux niveaux à des profondeurs respectives de 300 m et 400 m. Sur ces mêmes niveaux, des traçages ont permis de rainurer le minerai sur une longueur cumulée de 0.7 km. Les données de sondage et de rainurage ont servi à estimer les ressources du gisement selon plusieurs méthodes : sections, polygones sur longitudinale, grille sur longitudinale avec différentes pondérations en fonction des distances incluant le krigeage et enfin grille tridimensionnelle avec le même éventail de pondérateurs. La comparaison des estimés obtenus permet de mettre en évidence les facteurs importants dans l’estimation des ressources de ce type de gisement. Ces facteurs sont essentiellement géologiques et relatifs à l’interprétation de la géométrie des limites des corps minéralisés. Pour l’estimation sur grille tridimensionnelle, on a mis au point une technique originale qui calque l’interpolation des blocs à partir des échantillons sur cette géométrie des surfaces de contact. Le modèle résultant montre des variations internes de teneurs qui épousent les fluctuations d’épaisseur et d’orientation de la zone sans qu’il soit nécessaire de ré-orienter les fenêtres de recherche dans chaque bloc."

Jan 1, 2002

By Chuck Crowell

ISO Standards ?Provide Information to Address Commercial and Safety Needs for Standardization: ?Definitions and Terminology ?Test Methods ?Performance Criteria ?Conformity Assessment Process ?Developed by Global Experts ?Promote Global Harmonization

May 1, 2013

By J. M. Ortiz, J. P. Bertini

"In mineral resource and ore reserve estimation, several sources of information are generally available, such as diamond drillholes, reversed-circulation drillholes, and blastholes, and originate from one or more sampling campaigns and are analyzed by one or more laboratories. In such a situation, the grade measurements may not have the same precision and one should distinguish between hard and imprecise data.This work aims at studying the impact of data imprecision in resource/reserve evaluation through two case studies on simulated deposits: a porphyry copper deposit conditioned to real exploration and production data, and a gold deposit simulated without any conditioning data. Several geostatistical techniques are used to estimate the grades of selective mining units from exploration samples, including kriging, cokriging, lognormal and indicator kriging. Two types of imprecision are examined— measurements with multiplicative errors and measurements defined as intervals. The results are compared to the simulated grades of the selective mining units from a statistical and economic viewpoint.The study concludes that imprecise measurements should never be discarded because they help to improve the estimates, and that simple methods such as kriging are as efficient as more sophisticated ones for resource/reserve assessment. Finally, a few indications on how to diagnose and model the data imprecision are given."

Jan 1, 2005

By G. M. Behrend

"AbstractMeasurement and control systems in minerals processing plants are usually well thought out and designed. The criteria and design parameters have been interpreted correctly.However, these systems often fail to perform satisfactorily or break down altogether as a result of in-plant conditions which are unpredictable and over which the instrument systems designer has no direct control. The foresight necessary to anticipate the problems and allow for them in the systems design can only be generated by experience.This paper lists the most common of these problems and offers practical methods for their solution. It then follows with an analysis of instrument installation practices and comments on special points that need watching.Finally, instrument maintenance is discussed with a view to achieving good maintenance at the best possible economy.Good MeasurementGeneralTHE MINES and mineral processing plants of the nineteen seventies, after decades of sensible caution, have now committed themselves to extensive automatic control. X-ray analyzers are freely specified. Sample acquisition systems are efficient and automated, computers are reliable and relatively cheap, and computer control systems in conjunction with the new analyzers are operating in a good many plants and are proving to be profitable.The sight of shift foremen and floor operators assembled in front of a TV-tube and taking a computer data display as gospel truth is quite common now, and yet was quite unthinkable only ten years ago."

Jan 1, 1977

By F. Charette

The paper reviews the requirements of the instrumentation required to monitor mining excavations in a high stress environment, and the development plan to instrument the D-Bolt in such a fashion as to be able to follow the behaviour of the bolts in relationship to the ground movements and support performance. Recent field observations of D-Bolts under static and dynamic conditions are also presented. Also discussed is the assumed mechanical behaviour of the D-Bolt. D-Bolts are used in two (2) Canadian underground mines operating in high stress environments and tested in three (3) other operations.

Jun 1, 2012

By B. T. Lu

The corrosion and wear properties of a series of chrome white iron (CWI) castings were study using electrochemical and low-stress sliding abrasion tests. The results confirm that the corrosion resistance of these materials is largely dependant on the quantity of chromium in the matrix, while the wear resistance is mainly controlled by the volume fraction of chromium carbides. A pseudo-wear/corrosion map is developed to identify alloy compositions that may be suited for erosion/corrosion conditions.

Jan 1, 2005

By R. B. Kaunda

One fundamental requirement for surface and underground rock engineering is the ability to characterise the rock mass. An accurate characterisation of the rock mass allows rock engineers to optimize designs safely and economically. A number of classification systems have been developed in the past 50 years to help characterise rock masses such as RMR, Q system, Rmi, and several others. The challenge in developing rock characterisation schemes is often practicality, i.e. creating systems with relatively simple inputs for the everyday practitioner. A second challenge is the degree of subjectivity often inherent in commonly used classification systems. These challenges are especially exacerbated in weak rock or densely jointed rock masses. This paper introduces a new approach to characterise densely jointed rock mass using artificial neural networks and principal component analysis, based on principles commonly used in the geotechnical engineering of rock fills and waste rock dumps. Thirteen input parameters are dimensionally compressed using principal component analysis. Using a global database with more than 100 case histories, an artificial neural network is developed to conduct the rock mass characterisation. The advantage of this approach is less subjectivity as commonly used engineering (quantitative) terms are put to use. A further advantage is that given that the method is site-data dependent, it allows for ‘fine tuning’ of the model for a specific site.

Jan 1, 2015

By Louise Corriveau

A Targeted Geoscience Initiative transect in the eastern Grenville Province reveals an extensive VHMS-style cupriferous hydrothermal system among rhyolitic pyroclastic rocks of the Wakeham Group at La Romaine, Québec. The volcanic rocks outcrop sporadically along a < 10 km-wide by about 100 km-long belt correlated with the south-eastern extension of the Wakeham Group. This belt occurs among voluminous, magnetite-bearing, granitic gneiss. At Lake Musquaro, 1.51 Ga metarhyolitic to dacitic lapillistones and flows, locally with aluminous nodules and veins, are intruded by 1.49 Ga feldspar porphyries. This volcanic package was deposited on typical Wakeham Group arenite (< 1.52 Ga) interbedded with nodular, muscovite- and fibrolite-bearing gneiss, and minor marble hosting finely layered garnetiferous hornblendite, garnetite and magnetite-bearing coticule. The latter are interpreted as meta-exhalite and with the associated albitite (sodic alteration), aluminous veins (hydrothermal leaching) and magnetite-rich granitoids, they are key elements in the search for concealed mineral deposits in this area. At La Romaine, to the south, 1.5 Ga lapillistones outcrop structurally above metasediments and below a composite amphibolite unit of uncertain origin (lava or sills) with magnetite-rich (BIF?) units. An extensive zone of aluminous gneiss, with lapilli textures, provide evidences for severe hydrothermal leaching of the volcanic rocks prior to metamorphism. An adjacent siliceous vein-textured unit likely represent a zone of intense silicification (74 wt.% SiO2), while aluminous, hematite to magnetite-bearing veins in adjacent felsic gneiss (tuff?) preserve evidences for the sequence of alteration events. Despite granulite-facies metamorphism, the main characteristics of the amphibolite unit persist along the entire belt. This competent unit likely served as a cap rock; the garnetite, diopsidite and hornblendite it hosts provide effective guides to the sites of fluid discharge and mineralization. A number of Cu showings, modest in size, were discovered in this unit. Their systematic occurrence, in a structural-stratigraphic sense, indicates that this setting is attractive for mineral exploration despite high-grade metamorphism and deformation. Late-stage veins laden with fluorite crosscut these alteration zones, and are themselves metamorphosed, indicating that hydrothermal activity was polyphased. SHRIMP U-Pb ages obtained on detrital zircons (1 arenite) and on igneous zircons (5 volcanic rocks, 1 porphyry and 6 granitoids), pervasive arc-type geochemical signatures and presence of in situ rafts of barium-rich garnetite in the granitoids indicate that sedimentation and volcanism occurred between 1.52 and 1.49 Ga coevally with hydrothermal activity and emplacement of a sub-volcanic 1.5 Ga granitic batholith with early, 1.53 Ga tonalite intrusion. Such a geological context can sustain large-scale hydrothermal cells and development of VHMS, Cu-Fe oxides or SEDEX deposits.

May 1, 2003

By R. E. Hamilton

"The requirements for effective optimization of a mineral dressing operation are discussed, with specific reference to a flotation system . Also considered are the relation-ships between automatic control and optimization pro-grams. Variables are classified into the following groups, and the significance of the classification is discussed: (a) Directly measurable (b) Directly manipulable (c) Uncontrollable (d) Calculable from measurable variables (e) Affected by changes in manipulable or uncontrol-lable variables. New sensors for measuring variables not normally measured are described."

Jan 1, 1967

By John A. C. Fortescue

There is a need for better communication between scientists who plan and carry out mineral exploration research in glacial terrain and the exploration geologists who look for mines. In this paper, four ways in which workshops could be used to close this communication gap are described and discussed in relation to the solution of this problem in Canada.

Jan 1, 1973

By M. Behrouz

Thermal power plants convert thermal energy due to nuclear reactions or the combustion of coal, gas, heavy oil, or some other hydrocarbon to electrical energy. They consist of a variety of equipment, such as boilers, turbines, generators, cooling towers, and auxiliary equipment. Any factor that affects the equipment efficiency affects the overall efficiency. Analysis of the cooling tower and raw water using the Langlier Saturation and Ryznar Stability Indices showed that the cooling water at Sarchesmeh was slightly scaling with respect to silica. Cold lime softening was found to be a cost-effective method to produce cooling water with adequate properties to reduce the cooling water make up from 85 to 70 m3/h and blow down rate from 35 to 20 m3/h.

Jan 1, 2007

By F. J. Alcock

The Appalachian region of Canada comprises the three maritime provinces; Nova Scotia; New Brunswick; and Prince Edward Island; and that; part of the Province of Quebec lying south and east of Logan's fault. This; major thrust runs in a gently curving line from lake Champlain to Quebec; city and thence down the valley of the St. Lawrence to pass between Anticosti; island and Gaspe peninsula. To the northwest lies the St. Lawrence; Lowland division of the Interior Plains geological province; a region underlain; largely by early Palxozoic strata; which for the most part lie horizontal; or with low dips; where faults occur they are predominantly of the normal; type; and only locally are the beds cut by intrusive rocks. To the southeast; on the other side of the fault zone; an entirely different set of conditions is; encountered. There; Lower Devonian and older strata stand at high angles; are sheared and thrust faulted; and are intruded in many places by granitic; igneous bodies. The present paper is designed to outline briefly the geological; and structural history of this geological province and to emphasize; the part that structural conditions have played in connection with mineral; deposition.

Jan 1, 1954

By O. D. Maurice

"This paper will essentially update the information that is already known and published on the limestones of the Province of Quebec. The excellent report by M. F. Goudge (1935)m is difficult to improve upon and the areas of limestone quarrying are generally the same as they were at the time of Goudge's report. Our knowledge of the limestones of Quebec has been improved considerably in recent years by the publications of T. H. Clark, 2 who, since 1938, has been mapping and reporting on these lime-stones and has discussed their stratigraphy, their structural features, their history and their economic value. One economic aspect is the presence of natural gas in these formations and the possible occurrence of oil. A total of 150 test holes had been drilled to a depth of more than 500 feet by the end of 1967 and, in addition, at least 256 more shallow holes had been put down in the St. Lawrence Lowlands. The information from these test holes has greatly improved our knowledge of the thickness and extent. of the various formations of Paleozoic limestone and shale in Quebec.This paper will then review briefly the limestone occurrences in Quebec, using the old as well as the more recent reports as principal references"

Jan 1, 1970

By JOHN DUNFIELD

Good quality sphagnum peat bogs occur across Canada in areas of ample rainfall and cool, temperate climates. Early peat production techniques were restricted primarily to hand digging blocks of peat and piling them up to be dried by sun and wind. Suburban de velopment in the 1950s and the concomitant spread of home gardening triggered a dramatic growth in peat demand; labour costs rose in the same period. Peat production techniques had to alter accordingly. The three mechanical inno vations attempted were hydraulic mining, mechanical block digging and vacuum harvesting. Of these, the last method pro ved the most successful in Canada and is used to harvest 80% of Canadian peat production. Escalating transportation costs are the most important feature affecting future development of the Canadian peat industry.

Jan 1, 1984

By Knud Sinding

Mining firms are widely criticised for their adverse impacts on the environment. At the same time many firms in the industry devote extensive resources, both financial and managerial, to the reduction or elimination such impacts. Very considerable improvements have been made, although these are sometimes overshadowed by a few high-profile accidents, such as the occasional collapse of a cyanide-containing tailings dam. In parallel, much effort is also directed at projecting a positive environmental image, as witnessed by extensive environmental reporting, both on paper and increasingly through web-platforms. Mining projects today almost invariably involve some form of environmental protection. In industrial countries regulations in this area are extremely stringent, as is enforcement. In less well developed countries, regulation and enforcement may be weaker, but firms are in many cases and for a number of reasons committing themselves to high levels of environmental protection, even if they might get away without doing so. Research in the area of environmental performance of mining firms has so far paid much attention to concepts such as sustainability indicators and the sustainability of individual firms. Given the still raging debates about the appropriate way to determine the degree to which any given firm is sustainable (Welford 1995) as well as the usefulness of what will in the final analysis be a value judgement, anyone on the sidelines of the debate will come back to the fundamental issue, how is knowledge that a particular firm has been judged ?sustainable? going to be made use of. This issue remains unresolved, which may explain the lack of progress in formulating a useful definition of a sustainable firm The question addressed in this paper is not so much about what firms are doing on the ground or in any particular case of environmental protection, but more in the subsequent use of these efforts - and by extension - on the overall direction of corporate environmental strategy. The fundamental problem facing all mining firms is that they cannot easily benefit from unilaterally reducing their environmental impact. The firm can of course avoid liability and keep a variety of stakeholders happy and hence experience lower costs of obtaining the [input] resources they need (in a broad sense, not just minerals), but this represents only part of the opportunities available form pursuing an environmental strategy (Reinhardt 2000). The other part, which may have an enormous potential, involves the concepts of competitor management and product differentiation. The logic of keeping stakeholders happy has been most forcefully argued by Pfeffer and Salanchick (1978) who link the behaviour of firms in all domains to their ability to obtain the resources they need, at a cost that is lower than it would otherwise be (Pfeffer & Salanccik 1978). Several varieties of strategy can be included under this heading, including cost reduction and risk management. The alternative logic is to convince customers that they want to pay more for minerals supplied by mining firm X or directly attributable to mine Y, or by making all mineral users pay more. These two strategies, which may be referred to as product differentiation and competitor management, respectively (Reinhardt 2000) are related to the demand side of mineral supply, whereas cost reduction and risk management are related to the supply side. Mining firms have not pursued the demand side very much, if at all. This is probably due to the extreme difficulty of moving mineral products, bulky and unglamorous as they are, away from their

May 1, 2003

By John A. Hansuld

Geochemical dispersion of metals under various environmental conditions is discussed within the frame-work of Eh (oxidation potential) and pH (acidity). In general, two aspects are considered -(1) the oxidation of certain primary sulphides in the outcrop or sub-outcrop environment, and (2) the movement of metals in different dispersion media. Practical applications of each are illustrated by means of exploration case histories representing environmental conditions in the Canadian Shield, the southwestern United States and the Caribbean.

Jan 1, 1966

By Laxman M. Amaratunga, Nuri Hrnidi

"Reactive pyrrhotite tailings were agglomerated using the Cold Bond Tailings Agglomeration (CBTA) process with low cost binders; Portland Cement and fly ash. Various chemical additives, were used to retard acid mine drainage (AMD), including acid neutralizers, surfactants, sealants, and bactericides, which were encapsulated into the agglomerates. The choice of these additives was based on their low cost, low toxicity, and environmental friendliness. The main objective of the study was to examine the long term stability of these reactive tailings agglomerates towards AMD when used as aggregates for disposal in underground paste backfill.A carefully controlled kinetic stability test was carried out using specially designed humidity cells suitable for testing pellets. Using the humidity cell test method a 20-30 year AMD test may be accelerated to 50 weeks. During this period the following parameters were monitored: pH, redox potential, conductivity, sulphate, acidity, and dissolved metals.Results indicated that most of the encapsulated additives were successful in retarding AMD, while the control samples produced significant amounts of acid generation. The water soluble surfactant Enviroseal, and the sodium silicate sealant were very effective as a long term retardant for acid generation reactions in the sulphidic tailings when exposed to oxygen, water and iron-oxidizing bacteria.IntroductionThe sulphidic material discharged from concentrators becomes reactive upon exposure to air and/or water. Pyrrhotite (Fe0 S0_1) and pyrite tailings in particular which are discharged from the beneficiation process in the mining and mineral processing activities consist of finely ground particles. Upon exposure to oxygen and moisture, the tailings become reactive due to the instability of the metal sulphide minerals present which undergo spontaneous oxidation, thereby producing a weak sulphuric acid. Therefore, the long-term behaviour of the tailings can have a significant impact on the environment, due to acid mine drainage (AMD). AMD is created during natural atmospheric weathering when leaching action (natural and bacterial) conditions are present in the process wastes discarded during the mining and milling of sulphur bearing ores, and consequently it plays a major role in surface water chemistry."

Jan 1, 1998

By Robert B. Parsons

"It is easy to throw darts at government - and government often deserves to be a target. This month, Tax Notes examines tax legislation from a different angle, and sees some bright spots.The following article is based on a paper presented by the author at the International Gold Symposium in Rio de Janeiro in August 1989Introduction""No man&apos;s life, liberty, or property are safe while the Legislature is in session.”With one federal government, ten provincial governments, and two territorial governments all claiming to have constitutional rights to tax and otherwise regulate Canada&apos;s mining industry, and with each of these thirteen governments pursuing their respective rights with some vigor, government involvement in one way or another is an accepted way of life in the industry. While one&apos;s initial reaction to government involvement in an industry might be one of scepticism or fear, generally speaking the federal, provincial, and territorial governments in Canada tend to be pro-mining. They recognize the importance of the mining industry to Canada, especially in terms of job creation and exports. It is not surprising, then, to find that an array of valuable fiscal incentives are available to the industry through federal and provincial legislation.This paper summarizes the principal incentives that are inherent in Canada&apos;s tax legislation, as well as the Canadian Exploration Incentive Program. Although it is beyond the scope of this paper to deal with all of the incentives that are available, it is noted that various forms of federal or provincial assistance are also available outside of specific legislation, through negotiation with government departments. This latter type of assistance is generally directed toward helping with the cost of infrastructure such as roads or hydro lines, or Jess often toward loan guarantees or similar financing assistance."

Jan 1, 1990

By E. M. De Souza

"A scientific testing program, sponsored by the Mining Industry Research Organization of Canada (MIROC), was undertaken on the surface and underground facilities of Inca&apos;s Crean Hill Mine to investigate the effectiveness of using dry drilling with a dust control system.The surface test work consisted of the monitoring of advance rates and bit life white a series of 165 mm holes, wet and dry, were drilled at both mine air (0.69MPa) and high pressure air (1.72MPa). The results, based on statistical evaluations of field data, indicated that penetration rates can be increased by an average of 24% when drilling dry with high air pressure and by approximately 27.5% when drilling dry with mine air as compared with wet drilling under the same conditions. Dry drilling also has the effect of reducing button wear by approximately 69% using high pressure air. The underground test work employed a dust collection system developed for use with large diameter holes (165 mm) and high pressure drilling. The testing program has indicated that an average increase in penetration rate of 35% can be achieved when dry drilling in rock (waste) and of 49% when dry drilling in ore with high air pressure. Although preliminary dust monitoring did not indicate any appreciable increase in dust concentration during dry drilling, further dust monitoring is still required.A comparative cost analysis has indicated the potential for reduction in drilling costs when dry drilling is utilized. Further testwork is to be conducted to develop a reliable dust collection system for underground production."

Jan 1, 1992