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By L G. White

During 1958, prospecting parties working for the Mackenzie Syndicate in the Flat River area of the Mackenzie mountains, Northwest Territories, identified tungsten mineralization and located the property now being developed by the Canada Tungsten Mining Corporation Ltd. Scheelite mineralization, associated with pyrrhotite and minor chalcopyrite, occurs in lime silicate skarn replacement zones within a limestone-chert-argillite series intruded by granitic dykes originating from the ? main batholithic mass underlying the sedimentary beds. The results of surface outcrop sampling and 15,000 feet of grid-pattern diamond drilling have been combined to outline an orebody estimated to contain 1.32 million tons, grading 2.51 per cent WO after applying a 10 per cent dilution factor for mining purposes. T HE property of Canada Tungsten Mining Corporation Ltd. is located in the upper Flat River area of the Mackenzie mountains, Northwest Territories. Skarn-type replacement deposits containing scheelite mineralization are .situated between elevations of 4,500 and 5,500 feet above sea level along the east flank of the mountain range forming the boundary between the Yukon Territory and the Northwest Territories. The nearest supply center for the area is Watson Lake, Yukon Territory, located at Milepost 635 on the Alaska Highway.

Jan 1, 1963

By Marc C. Bétournay

Hydrogen fuelcells are a known technology, having been applied to stationary (e.g equipment, buildings, power plants) and vehicle applications (e.g transit buses, space shuttles). There is currently a growing need to provide alternate power systems to diesel fuel for underground mining vehicles to improve underground air quality and reduce production costs and green house gas emissions. To date, however, fuelcells have not been exposed to underground mine air and physical conditions. A testing program was carried out to provide information on the vulnerabilities of fuelcells as part of a number of proof-of-concept projects to apply hydrogen power to underground mining vehicles. The fuelcell type of choice for the industry, the Proton Exchange Membrane, would function at the range of temperatures encountered in underground and surface operations, and use hydrogen that is stored under low pressure and risk. A small fuelcell stack was tested in a cooperative project between CANMET, the Fuelcell Propulsion Institute, INCO, the Ontario Ministry of Labour, Sandia National laboratories and H-Power. This article will review the tests carried out to measure the effects from high humidity, mineral dust, diesel emission gasses and diesel particulate matter as well as from shock and vibration provided to the unit in underground conditions, at INCO?s 175 Orebody minesite and INCO?s Stobie Mine. The test results provided will show that the unit was not affected by the underground conditions: physically and electrically the unit performed without any reduction in operation or adverse effects imposed.

May 1, 2003

By J. B. Boisvert, P. Oshust

A significant source of uncertainty in the diamond resource contained in kimberlite pipes is the volume of the pipes. Often the material within a pipe will be mined as ore, leaving the actual geometry of the pipe as a significant source of uncertainty. It is desirable to use stochastic techniques, rather than deterministic methods, to model pipe geometry because stochastic techniques generate multiple realizations that are reproducible and can be used to assess uncertainty in pipe geometry. The proposed methodology uses sequential Gaussian simulation of pierce point locations interpreted from drillholes through a kimberlite pipe. Kimberlite pipes are approximately cylindrical in shape; therefore, the data are transformed to cylindrical coordinates to facilitate the simulation of pipe geometry. Rather than using xyz coordinates to define the pierce points, z, ??and pipe radius are used. The radius variable can be simulated in z-??space to generate multiple realizations of pipe volume. Uncertainty in the volume of the pipe can then be evaluated. This methodology is demonstrated with a kimberlite pipe at BHP Billiton’s Ekati diamond mine.

Jan 1, 2008

By Krishna Parameswaran

"This paper discusses energy use and conservation in the primary copper industry and illustrates eco-efficiency considerations, using select examples of practices at ASARCO LLC, an integrated primary copper producer and others in the industry that promote eco-efficiency. The World Council for Sustainable Business Development first publicized the concept of eco-efficiency at the Rio Earth Summit in 1992. Eco-efficiency is a management concept linking environmental and economic performance and is aimed at generating added value for a business through, among other things, increased resource and energy conservation and reduced environmental impacts throughout the life cycle of the product or service. This concept differs from sustainable development in that focus is only on economic and environmental factors and does not include social considerations. In the metal mining and processing context, this added value can be realized by implementing practices that promote conservation of water and mineral resources, conservation of energy, minimization of waste, reduced emissions and effluents and increased recycling. The examples from the primary copper industry used to illustrate eco-efficiency considerations include: water and energy conservation in mineral processing, adoption of flash and bath smelting processes, emission reduction and process improvement associated with fire-refining, implementation of green chemistry in electrorefining, promoting product stewardship initiatives and fostering renewable energy project on disturbed mined lands.INTRODUCTION ASARCO LLC (Asarco) was organized in 1899 as the American Smelting And Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co-products. Grupo México, S.A.B. de C.V acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, molybdenum, selenium and tellurium. Asarco operates three open-pit mines and mills, two leach, solvent extraction-electrowinning (SX-EW) plants and a copper smelter in Arizona and a copper refinery in Texas."

Jan 1, 2017

By K. Lundholm, M. Andersson, L. Nevatalo, Å. Holmström, L. Hedström

"Several copper deposits have the arsenic bearing minerals enargite (Cu3AsS4) and tennantite (Cu12As4S12). Since this mineral contain both arsenic and copper, it is not possible to remove the arsenic by selective flotation. Partial roasting is a method to clean the concentrate from arsenic and thereby produce a suitable raw material for the copper smelter. Also mercury is commonly found in copper bearing minerals. In the partial roasting process both arsenic and mercury are volatilized, while part of the sulphur is used as energy during the roasting. This gives a calcine suitable as feed to a smelter, much like an ordinary copper concentrate. A typical analysis of calcine would be: S content 18–22%, As content below 0.3%, Cu content – not affected, grain size – not affected. However, if the concentrate contains mercury, the mercury will be volatilized during the roasting process. This will lead to very high mercury contents in the subsequent process of sulphuric acid, unless the SO2-rich process gas is pre-treated by the Boliden/Norzink process that recovers mercury as calomel, Hg2Cl2. The volatilized arsenic in the gas phase can be recovered either by dry or wet methods. However, one problem is that arsenic also contaminates the fine grained calcine dust that is captured downstream in the gas cleaning system. The calcine dust contains valuable metals such as copper, gold and silver that needs to be separated from the arsenic. The ultimate aim is to stabilize the recovered arsenic as a compound with minimum impact on the environment and recover the valuable metals. By using wet recovery methods it is possible to selectively precipitate copper, gold and silver as sulphides while arsenic is kept dissolved in the liquid. The precipitated metal sulphides can be mixed with the calcine and sent to the copper smelter. The dissolved arsenic is sent to effluent treatment and is further treated in Outotec ferric arsenate precipitation process, where arsenic is precipitated as the stable compound basic ferric arsenate, formula FeAsO4·xFe(OH)3. All concentrates containing arsenic are unique and the process design of a roaster plant must be based on relevant process data. The process data is collected during tests in lab scale and pilot scale, where the influence of critical process parameters on the quality of calcine is studied. The ability to run tests both in lab scale and pilot scale is crucial to the development of the correct roasting process. Outotec is well equipped for this."

Jan 1, 2014

By D. A. Karvonen

In 1970, the Government of Saskatchewan instituted a program aimed at resolving the dilemma of excess productive capacity over the market demand which existed for potash produced in Saskatchewan. The two primary elements of the program were prorationing of potash production to market demand and a minimum selling price. The paper reviews the factors, both local and international in nature that led to the introduction of the program. The licensing mechanics and the operation of the program, along with the changes that have been introduced in two and one-half years of operation, are discussed. Attention is given to the results of the controls as they affect the industry and the province. Also discussed is the outlook for Saskatchewan potash in world markets.

Jan 1, 1973

By Gareth Barnes

Traditional approach to improvement is driven by good ideas from good people, but whilst the business case may sound good, when the project is complete, we often have not delivered on expectations.  Why not? The best way to successfully predict the outcomes of an improvement effort in a complex process is through using statistical modelling, which considers the impact of uncertainty within interacting processes.  Applying Theory of Constraints in a model helps leaders to quickly determine: Where the constraining process(es) is/are Where improvements will add the most value How much improvement should be targeted - before the next constraint takes over The confidence level of achieving a given target, which gives us a clear pathway to improvement. This paper presents an analysis of statistical modelling applications at Vale’s Manitoba Operations to achieve the 2025 targets. Using statistical modelling of the Business Structure, the team identified a series of process improvements through a Theory of Constraints Analysis. Value Stream Maps (VSMs) were used to define the required data, apply statistical modelling, and conduct training sessions enabling the Manitoba team to identify the constraining influences. Scenario testing in the Statistical models helped identify the Hierarchy of Constraints and specify the pathway to improvement. How to Improve a Business Video link https://vimeo.com/344418155

May 4, 2025

By David G. Almond

"Economies of scale and the variable characteristics of many large ore deposits have resulted in grinding installations having large SAG mills fitted with variable speed drives. Problems associated with effective operation of this equipment has created the need for better operator knowledge of mill load behavior and the need for new instrumentation capable of providing accurate information about load movement and composition. This paper discusses two performance enhancing instruments available to address these needs.INTRODUCTIONThe economic demands of new mining projects has resulted in increased equipment sizes and this is particularly evident in milling where there are now many SAG mills operating in the range of 28’ – 40’ diameter with installed powers of 8 – 22 MW. These mills are designed to process very high capacities of ore daily2 and the variable characteristics of many of the deposits mined results in the need to vary the mill speed during processing to cater for the changes in ore hardness. Mill speed changes often result in operational problems associated with high-energy impacts striking the mill liners reducing energy efficiency as well as degrading the grinding media through breakage, accelerating liner wear and in extreme cases even breaking liners. These operational problems have given rise to the need to have instruments aimed at providing operators with accurate information in real time about the load composition and movement within SAG mills.The original concepts for operating SAG mills were derived from past experience of operation of conventional fixed speed ball mills. However, the relatively stable conditions that applies with fixed speed and constant ball charge in ball mills supports theoretical approaches to the grinding process based on energy calculations such as Bond’s Work Index concept. Later a set of parameters Si and Bij were used for describing load kinetics, but all of these methods neglect the details of load movement and how the energy is actually used inside of the mill. It is now commonly accepted as a basic rule that SAG mills grind by impact whilst ball mills grind by attrition and consequently SAG mills are designed and operated to generate a large amount of impacts by the cataracting load without paying sufficient attention to where these impacts are actually occurring. Many mills are operated on the basis that as long as the mill is consuming the expected power there is little attention given to the class of bodies using this energy and this often results in the inefficient use of energy."

Jan 1, 2005

By H. P. Jacobi

"INTRODUCTIONPine Point Mines, operated by Cominco Ltd., is located approximately 65 miles east of Hay River, N.W.T. on the south shore of Great Slave Lake.The milling operation started in the fall of 1965 with a capacity of 5,000 tpd. An addition was put into operation late in 1968 to bring the nominal capacity up to 8,000 tpd. The present milling rate is 11,000 tpd.With a feed grade of approximately 2.9% Pb and 6.0% Zn the annual concentrate production amounts to roughly 130,000 SDT of lead concentrate and 370,000 SDT of zinc concentrate for a total of 1/2 million tons of product.This tonnage is moved by railroad. Pine Point is served by the Great Slave Lake Division (G.S.L.) of the Canadian National Railways which connects to the Northern Alberta Railway System (N.A.R.) at Roma Junction, at Peace River, Alberta. The system in turn connects to the CNR and the CPR in Edmonton, Alberta. From here the concentrates move inland chiefly to Trail, B.C., with some shipment to other Canadian and U.S. smelters, and to the port facilities of Pacific Coast Terminals at New Westminster, B.C. for offshore export.This paper will focus on the problems associated with the movement of lead and zinc concentrates from Pine Point to port facilities on the west coast."

Jan 1, 1975

By A. Dave Mackintosh

In 2001, at the CIM AGM in Quebec, a paper discussing poor ground conditions in a newly opened area at Agrium?s Vanscoy Potash Operation?s, suggested load transfer around old workings as a possible reason for the early room failure. High closure rates are expected in deeper regions however the rapid failure of walls immediately behind the face resulted in protective guards being mounted on and behind the borer. The high closure and early rib failure continued well past any reasonable distance to be explained by load transfer around old workings and investigations continued into possible reasons other than simply depth. Detailed investigations into the mineralogy and crystal fabric of the ore zone provided one possibility, which combined with a changed borer cutting profile are now believed to have contributed greatly to the poor conditions.

Apr 1, 2005

By B. Goard

"IntroductionCemented backfill has been placed underground in slurry form in Inco Limited's Ontario Division mines since the early 196Os. The slurry was traditionally mixed on surface at between 65 and 70 wt% solids* and transported underground via gravity through a borehole-pipeline distribution system. This method of placement, while simple and dependable, has proven to be costly because of the large amounts of transport water involved.A significant quantity of the slimes buildup on mine levels is caused by the backfill water carrying cement and other fine material out of the stopes. The level cleanup and eventual pumping or hoisting of the slimes and water back to surface result in substantial indirect backfilling costs.The cement that remains in the stope is always overhydrated because of the high water cement ratios that exist. As a consequence, high concentrations of Portland cement must be added to the backfill to produce the fill strengths required for the different mining methods.Pouring backfill at these densities also demands extensive fill preparatory work in the stopes to withstand the hydraulic heads created by the slurried fill. This, along with the delays in pouring necessary to allow for water drainage, result in significant losses in productivity.These negative aspects of slurry placed fill has led Inco Limited to investigate several methods of transporting backfill underground via pipeline, at higher densities (i.e. 75 to 95 wt.% solids). Three separate transport methods are presently being experimented with by the Company's Mines Research Department. Each utilizes a different technique or form of flow transport, i.e. concrete pumping technology, high density slurry flow, and pneumatic conveying."

Jan 1, 1987

By C. Piribauer, E. Feichtenhofer, A. McEneaney

"As part of a major diversification project, RHI AG, through its plant in Drogheda Ireland, has developed a Caustic Calcined Magnesium Oxide (CCM) for use in the Cobalt (Co) & Nickel (Ni) hydrometallurgical extraction industry. In the course of the project, the company investigated the chemical and physical properties of a number of different Magnesia’s used in Co & Ni hydrometallurgy applications and has been able to determine the important parameters for a successful Magnesia for this application. A number of live plant trials have confirmed the results of this testwork and the company is now proceeding to produce this product in commercial quantities at Premier Periclase Ltd., the RHI AG plant in Drogheda, Ireland. This paper will outline the development work conducted by the company and highlight the important chemical and physical properties that make a successful CCM. Much of the research was conducted at the RHI Technology Centre in Leoben, Austria. In addition, a number of external laboratory studies were conducted on behalf of RHI AG. The result of this work has allowed the company to develop a Magnesia product with optimised properties for use in the Cobalt and Nickel hydrometallurgical extraction process.INTRODUCTION Premier Periclase is part of RHI AG, a globally operating supplier of refractory products, systems and services, headquartered in Vienna, Austria. The company produces Magnesia from seawater at its plant in Drogheda, Ireland. While the main focus is on production of refractory grade Dead Burned Magnesia for the steel industry, the plant also produces a number of different grades of Caustic Calcined Magnesia as well as Magnesium Hydroxide products. As part of a major project to diversify the company’s product base, the use of CCM in the Cobalt (Co) & Nickel (Ni) hydrometallurgical extraction industry was investigated. One of the company’s highly reactive grades of Caustic Calcined Magnesia was found to be particularly suitable for this application. In an effort to understand what makes a successful Magnesia for hydrometallurgy the chemical and physical properties of different Magnesia’s used in Co & Ni hydrometallurgy were investigated. This paper and conference presentation outlines the findings of this process."

Jan 1, 2017

By Michel G. Grenier

Compliance with Diesel Particulate Matter (DPM) exposure regulation is currently performed using timeweighted average (TWA) sampling on underground mine workers. These samples are collected in the span of an entire shift and the resulting concentrations are compared to a legislated exposure limit. While this is very useful to determine the exposure level of an individual to DPM, it fails to clearly identify causes of exposure and highlight opportunities that could help reduce the exposure of workers in the course of the work shift. Real-time DPM monitoring measures the worker?s exposure as a function of time and helps identify circumstances where corrective actions can be taken or design changes can be made by the individual or the employer to reduce the overall exposure of the worker and peers. This work focused on obtaining DPM concentrations using a real-time polycyclic aromatic hydrocarbon (PAH) monitor. The aim was to demonstrate that this instrument, while not a direct DPM analyzer, was able to provide a concentration profile that could easily be linearly correlated to standard TWA elemental carbon measurements. In addition, several instances of improvements that could be implemented to reduce the exposure of underground employees were demonstrated.

May 1, 2010

By L. Vollert

In-situ recovery of metals is presently experiencing a revival not seen since early applications in amenable copper oxide deposits, uranium and generally applications where neither, porosity and permeability, nor process chemistry have been prohibitively difficult. With ever decreasing grades in current mining operations or Greenfields projects and ever increasing capital and operating costs, in-situ recovery is looked to as the processing option that will both unlock these deposits as well as potentially derive revenue from mineralised waste remaining in the ground once traditional mining and processing methods become uneconomical. In-situ recovery is also being looked to as a mining method that minimises the environmental impact sustained in the application of traditional energy and water intensive mining and processing operations where millions of tonnes of ore are mined from the earth, processed on surface and then disposed of in both waste dumps and tailings facilities. The key challenge facing companies like Newcrest is that these low-grade deposits or remnant mines are generally hard rock applications that require costly methods to liberate the valuable minerals. A further challenge includes identifying suitable chemistries that both facilitate the economic recovery of gold and copper and that may be considered environmentally acceptable. This paper presents a desktop study whereby the issues of access creation and chemical extraction are discussed and evaluated with a view to driving future research in the area and unlocking this application as a real processing option. INTRODUCTION Mining companies are increasingly challenged by low grade, deep and complex ore deposits which are no longer economically exploitable by current methods. The large footprint of current open pit operations can present obstacles for permitting and social acceptance. For these reasons in-situ recovery (ISR) technologies are receiving renewed attention as a technology which could be used to exploit these more complex deposits economically and with less environmental impact. The environmental impact may be further reduced if emphasis is placed on use of renewable energy sources rather than traditional grid power, gas turbine or diesel generators are employed to drive the operation. A potential renewable energy driven ISR mine of the future is shown in Figure 1.

Jan 1, 2019

By J. Ran

There are challenges in mining deep tabular ore deposits using the open stoping method, particularly mining remnant panels towards the end of mine life. The remnant panels have experienced stress concentration and are in the failing or post failure state causing drilling and loading difficulties, ground movement, induced seismicity and ground instability problems. As more mines are going deep, without effective ground control management, the mine production will be interrupted and equipment damage and personnel injury are likely to occur. Mining at Falconbridge Lockerby Mine located in the Sudbury Basin was concentrated in the deep zone from late 1990s to 2004. The remnant panels situated approximately from 1800m to 1920m below surface were mined in 2004 before the mine closure. These panels were in the central section of the orebody along strike. The orebody was relatively narrow ranging from 5m to 15m and steep dipping at 70o to 80o. Because of the retreat mining sequence and the mining depth, stress concentration, wall closure and seismicity had caused a number of mining difficulties. Managing these challenges was critical in achieving the mine production target without compromising personnel safety and excavation stability. A comprehensive ground control management approach was adopted to mine the remnant panels at depth. The measures taken included ground movement monitoring, understanding the movement pattern of the footwall rock and selecting appropriate support systems, analyzing seismic monitoring data and defining re-entry protocol, brow support design and restricting access. This paper presents these ground control measures and the experience gained in successfully mining the deep remnant panels at Lockerby Mine.

Apr 1, 2005

By Brigitte Lacouture, Yeen Shien Hwang, David Lin

"A baseline survey of the partially open lead regrind circuit at Red Dog Mine indicated poor regrind efficiencies for the three parallel 450 HP tower mills. Driven by the high energy cost and the potential metallurgical gain brought by improved mineral liberation, the Red Dog lead regrind circuit was optimized in two stages.In the first optimization stage, different circuit layouts were evaluated in two plant trials. In June 2003, the regrind circuit was changed to a fully closed circuit. This reduced the tower mill requirement from three to two mills. The circuit modification payback was 11 days through power savings alone.The second stage of optimization was the evaluation of reagent addition. To improve pyrite depression, sodium cyanide was added to the feed of the lead regrind tower mills and tested in a series of plant trials over several mill feed stockpiles. Galena selectivity against pyrite was found to improve in these plant trials. Due to environmental sensitivities, no net increase in cyanide addition to the plant occurred and thus no increase in the cyanide concentrations in the tailings pond or the environment will result.The lead regrind optimization work improved the overall lead metallurgical performance and reduced energy and reagent costs. Economic analysis showed that annual profit increased by as much as US$3.0 M."

Jan 1, 2005

By C. Turek, R. Henderson

Mine planning is the foundation of value for a mining company. Good mine planning requires solid understanding of the ore body, rigorous standards and processes, robust and useful information technology and skilled people. Life of mine planning is key to identifying strategic direction for any mine and short range mine planning is key to delivering forecast and budget expectations. Mine planning at Kinross has been identified as a critical success factor and initiatives are being prepared to improve the quality of our plans and to build bench strength in our teams. The Kinross Way for Mine Planning (KWMP) has been developed and implemented to establish the standards to ensure a strong business foundation. This paper briefly describes the process used to develop the KWMP and presents a selection of mine planning best practice initiatives at Kinross mines.

Jan 1, 2011

By James R. Lang

The Xietongmen deposit is located 350 km west of Lhasa, Tibet. It is a new, high-grade porphyry copper-gold discovery and the first deposit to be systematically explored by a western company in southern Tibet. In 2005, Continental Minerals Corporation drilled 21,332 m of core in 63 holes and demonstrated excellent lateral and vertical continuity of high-grade copper-gold mineralization over an area 750 m by up to 350 m in size which remains open in all lateral directions. Drill intersections repeatedly yield grades >1% Cu equivalent (based on gold and copper prices) and include 308.5 m at 0.87% Cu and 1.25 g/T Au (1.60 CuEQ%), and 315.6 metres at 0.61% Cu and 1.11 g/T Au (1.26 CuEQ%). Extensive drilling in 2006 will expand and delineate the deposit, and metallurgical, engineering, environmental and socio-economic evaluations will begin. Xietongmen is hosted by volcanic and intrusive rocks of the Gangdese belt, a magmatic arc active between 120 and 30 Ma along the southern margin of Eurasia. Pervasive alteration is dominated by a well-mineralized K-feldspar and biotite assemblage, and by a more peripheral sericitic assemblage also with strong chalcopyrite. Major vein stages include chalcopyrite-bearing quartz, biotite, magnetite and pyrite-pyrrhotite types.

May 1, 2006

By M. J. McLeod, S. Watters, G. G. Lutes, S. Castonguay

"Gold-bearing mineralization at Anomaly A occurs in polydeformed Ordovician turbidites of the Kendall Mountain Formation of the St. Croix belt in southwestern New Brunswick, and is hosted by WSWtrending, shallow-dipping, brittle-ductile high-strain zones associated with the latest stage of the second of four regional deformation events. Gold-bearing syn-deformational stockwork, massive, and multiply brecciated quartz-sulfide veined zones form irregular pods and sheets up to several meters thick, which contain arsenopyrite, pyrrhotite, pyrite, stibnite, and a variety of rare minerals that are gold-bearing. Mineralized zones are enveloped by locally auriferous, weakly to intensely altered wall rock. Vein paragenesis includes: (1) early (pre- to syn-D2) quartz-chlorite veins that are largely the product of migration of quartz by pressure solution; (2) crosscutting, multiphase, vuggy quartz-sulfide veins that contain most of the gold and are interpreted to be structurally controlled; (3) late, crosscutting, nondeformed, non-gold-bearing veins containing laumontite, chlorite, muscovite, quartz, fluorite, and base metal sulfides. Carbonate-poor alteration associated with zones of gold mineralization is lithology-specific, and appears to reflect overprinting of multiple events. Major elements removed during alteration include Si, Na, Mn, and Mg. The minor and trace elements removed include Co, Li, Sc, and possibly Sr, Ni, and Zn. Minor and trace elements added include Au, Ag, As, Sb, S, and possibly F, Cu, Pb, and Zr. On the basis of proximity, time constraints, and a similar ore mineral assemblage, gold mineralization at Anomaly A is interpreted to be a distal equivalent of the intrusion-related gold mineralization at the nearby Clarence Stream Main zone deposit. La minéralisation aurifère de l’Anomalie A se trouve dans des turbidites Ordoviciennes polydéformées de la Formation de Kendall Mountain, dans la ceinture de Ste-Croix du sud-ouest du Nouveau Brunswick, où elle est contenue dans des zones de déformation fragile-ductile à faible pendage de direction OSO associées au dernier stade du second de quatre épisodes de déformation régionale. Les zones aurifères syn-déformationelles se présentent en forme massive, de stockwork, ou de veines de quartz-sulfure bréchifiées à répétition formant des lentilles irrégulières et des couches de plusieurs mètres d’épaisseur contenant de l’arsénopyrite, de la pyrrhotite, de la pyrite, de la stibine, ainsi que divers minéraux aurifères rares. Les zones minéralisées sont entourées d’une enveloppe de roches faiblement à intensément altérées, localement aurifères. La paragénèse des veines comprend : (1) des veines précoces de quartz-chlorite (pré- à syn-D2) qui sont principalement le produit de la migration du quartz par solution-pression; (2) des veines polyphasées de quartz drusique et de sulfures contenant la plus grande partie de l’or, celles-ci sont considérées comme étant sujettes à un contrôle structural; (3) des veines tardives stériles, sécantes et non déformées contenant de la laumontite, de la chlorite, de la muscovite, du quartz, de la fluorite et des sulfures de métaux usuels. Les zones de minéralisation aurifère sont associées à une faible altération en carbonate contrôlée par la lithologie et semble résulter de la superposition d’événements multiples. Les éléments majeurs perdus durant l’altération sont le Si, le Na, le Mn et le Mg. Les éléments mineurs et traces perdus durant l’altération sont le Co, le Li, le Sc et possiblement le Sr, le Ni et le Zn. Les éléments mineurs et traces enrichis comprennent l’Au, l’Ag, l’As, le Sb, le S et possiblement le F, le Cu, le Pb et le Zr. Étant donné sa proximité géographique, les contraintes temporelles et les similitudes de leurs assemblages minéraux, la minéralisation aurifère de l’Anomalie A est interprétée comme un équivalent distal de la minéralisation aurifère associée aux intrusions du gisement avoisinant de la zone principale (Main"

Jan 1, 2008

By P. R. Day, W. K. Webster

"The introduction of large boreholes underground initially involved taking the techniques of open-pit bench blasting to the production stope, but with deeper boreholes and narrower stopes more controlled techniques must be developed in order to maintain good stope walls and prevent dilution of ore or structural damage to pillars due to blasting overbreak. The points discussed are drilling accuracy and drill pattern, the relationship between open-pit wall control and underground mining, the varied explosives products and initiation devices available, and some of the many ways that variations in loading, such as deck charging, etc., can produce desirable results.IntroductionThe use of large-diameter blastholes for underground mining began ten years ago and today they are widely employed in a variety of orebodies and stope configurations. These big blastholes, which range in size from 4.5 to 8 inches in diameter, were originally employed in the same manner ' as open-pit bench blasts; that is, the stope was silled out to full width and all holes were drilled vertical and parallel. This was suitable for competent, massive orebodies, however the popularity of the big drills saw their usage in more narrow stopes, often with poor ground conditions. The dipping orebodies and small drill sublevels resulted in inclined drilling.Today, there is full-ring drilling of 4.5-inch holes. Some 6.5-inch holes are drilled up to 350 feet deep. A 350-foot borehole may contain 6000 to 7000 pounds of explosive. The detonation of this size of charge weight within the confines of an underground stope can have considerable effect on the stability of stope walls and adjacent pillars. Obviously, precautions must be taken to minimize the damage which would result from the large charge weights possible with these big boreholes."

Jan 1, 1982