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By C. G. Anderson

Alkaline sulfide leaching technology (i.e. ASL) has been studied, presented and published throughout the literature and utilized in some current engineering studies. Yet, the actual industrial applications are very few and the knowledge about these is very limited. Hence, a large gap between the laboratory, publications, engineering studies, and the actual industrial plant exists. Recent studies of ASL applied to copper enargite concentrates definitively bear out this dichotomy. Hence, this paper will seek to dispel the common misperceptions that continue to surround the selective industrial ASL hydrometallurgical technology. For edification of the reader, a listing of ten common misconceptions and myths is listed. As well, ASL history, fundamental aspects and a new flowsheet application for simultaneous gold and high purity antimony oxide production from low grade materials is included. The associated estimated economic considerations are also included to heighten enlightenment about the application of this industrially proven technology.

Jan 1, 2014

By Charles Camsell

THE Northwest Territories covers a very large area-more than one-third of all Canada-and its most northern point, Cape Columbia in Ellesmere island, is distant only 500 miles from the Pole. Our first knowledge of the Arctic Archipelago, of which Ellesmere island forms a part, resulted from a gold-mining venture in Queen Elizabeth's reign. The English navigators of that time were eager to find a north-westerly and shorter and Jess hazardous route to the riches of China and Japan than that which Magellan had discovered, but they were unaware that the continent then known to bar a direct route extended in great width far to the north. Frobisher was one of these navigators. He reached in 1576 the bay in Baffin island now named after him, convinced that he had found a passage connecting the Atlantic with Asiatic seas. Forced to re-turn after ordeals in which ice, wind, and Eskimos flayed formidable parts, he brought back, among other novelties, a piece o black stone which had been picked up casually by one of his officers, and gave a little of it to the wife of one of the venturers, or financial backers of the enterprise. To quote now from Hakluyt: ? 'She by chance threw and burned it in the fire so long that , at length being taken forth and quenched in a little vinegar, it glistered with a bright marquesset of gold. Whereupon the matter being called in sorne question, it was brought to certain goldminers in London to make assay thereof, who indeed found it to hold gold and that very richly for the quantity." On the strength of this, the venturers, anticipating much profit, launched a second expedition to secure more of this stone, and 143 persons, including 14 miners and finers, set forth in 1577 and returned the same year, with, however, 200 tons of another mineral. Influenced by glowing accounts of veritable mountains of this mineral and by assays made after "additaments"-that is how "salting" in those days was described-the venturers, including Elizabeth, supplied funds for erecting a smelter and refinery at Dartford and outfitting a stilllarger expedition. And so, in 1578, fifteen ships departed with the Queen's blessing, for the same remote shores. After many mishaps, they returned with over 1,000 tons of the mineral, but when it yielded very little of value at the works in Dartford, the? Company of Venturers was forced into liquidation. Though our first prospector and miner was rather inconsiderate of the investors, he proved the existence of an archipelago, hitherto unknown, and secured much information about the new land and its dwellers.

Jan 1, 1938

By S. Razavialavi

In the planning phase of every construction project, layout of temporary facilities is a crucial task; site layout can affect safety, travel cost and time, construction productivity, and space utilization. However, site layout planning can be a complicated problem, due to the interdependency of influencing factors. Although interaction among activities is one of the major drivers of site layout planning, it has not been properly addressed in past research. In this study, simulation is presented as a promising tool to address this gap. The capability of simulation technology to model complex processes in construction projects makes use of simulation tools in site layout optimization problems effective, while existing methods are unable to perfectly model these problems, in some cases. Additionally, the advantages and challenges of implementing simulation are assessed and a generic framework for simulation application in site layout planning is proposed.

Aug 1, 2013

By M. Pötsch, W. Schubert

"The kinematic analysis of rock blocks is one part of a block stability assessment. It provides information about a block’s movability, i.e. if a block can detach from the adjacent rock mass and move towards the free space. This paper introduces an analytical method for the analysis of pure rotations of arbitrary finite polyhedral blocks. It enables the engineer to judge a block’s rotatability about a corner or an edge. The method is presented using a graphical and computational method. The application of the method is illustrated with an example. INTRODUCTIONThe kinematic analysis of rock blocks deals with the determination of the movability of blocks. Established methods typically cover: (a) translational motion (John 1968, Markland 1972, Londe et al. 1969, 1970, Goodman & Shi 1985, Warburton 1981) and (b) the specific rotational cases Toppling (Goodman & Bray 1977) and Slumping (Kieffer 1998). Mauldon & Goodman (1990, 1996) and Tonon (1998) introduced rotational kinematic analyses for three-joint pyramids and tetrahedral blocks extending Goodman & Shi’s block theory.All mentioned methods are subject to assumptions that limit the applicability to engineering problems. For example, the kinematic test of daylighting joints or intersections inherently assumes a finite block, which only can be proved by the finiteness theorem (Goodman & Shi 1985). Daylighting of an intersection or plane is not a sufficient condition for removability. Goodman & Shi’s and Warburton’s methods are limited to translational block motion. The methods for block rotations so far address tetrahedral blocks only. They also address only pure rotational modes and neglect the general motion of a rigid body. This paper introduces an analytical method for the analysis of the kinematic rotatability of finite rock blocks. It extends Mauldon's and Tonon's theory of rotatability of tetrahedra to arbitrary polyhedral blocks. A graphical method using the stereographic projection and a computational method are presented."

Jan 1, 2015

By J. Janzen

The cost to supply ventilation may exceed 40% of the total mine energy cost for underground mines and is often higher for deeper mines. The goal of Ventilation-on-Demand (VOD) is to ensure that the required quantity and quality of air is supplied to underground mining crews and diesel equipment at the least energy expenditure (minimum cost). A VOD system may include control of surface fans (Supply & Exhaust), underground booster fans, auxiliary fans and automated regulators/dampers to regulate the flow of air with more control elements providing more value. Strategically located Air monitoring stations measure air quantity and quality and provide feed-back enabling control. The modular design involving controls, intelligent instrument and intelligent motor control centres coupled with a communication network allows the quick installation, commissioning and expansion of the system as the mine develops. The result is a very robust, flexible system while reducing maintenance costs and spare parts. This paper discusses the impact of sensors, installation and commissioning on advanced controls and provides solutions for in-field applications.

Aug 1, 2013

By G. S. Hume

Introduction O WING to the mineral discoveries which have recently been made in the Great Bear Lake region and the possibility of the need for fuel for transportation and development, it seems.timely ro review available information regarding the oil prospects in the vicinity of Great Slave lake and Mackenzie river, where a vast area is underlain by Palreozoic and younger sediments that undoubtedly are petroliferous. Exploratory surveys were carried out in this area by the Geological Survey and others in the latter part of the 19th century, but it was not until 1920, when drilling for oil actually began, that any serious attention was paid to the oil prospects. This is readily accounted for by the remoteness of the region, the lack of quick transportation facilities, and the shore summer season. Numerous and copious oil seepages had been reported, however, from widely separated localities, and interest was stimulated by the knowledge that these occurred in Devonian strata which had given a remarkable record of sustained production of high-grade oil in the oil-fields of southwestern Ontario. . Accordingly, during the four years 1920 to 1923, inclusive, several parties sent out by the Geological Survey made as thorough an investigation of various parts of the area as seemed warranted at that time, and from these surveys most of our information regarding the details of the stratigraphy is derived. In such a large area, it is inevitable that the lithology and thickness of rocks of the same age would show wide variations, and hence it should be recognized that conditions as regards oil prospects in the vicinity of the west end of Great Slave lake are quite distinct from those that occur near Fort Norman, 400 miles farther to the northwest, and these again are in all probability quite different from those in the less well known Arctic Red River area, 250 to 300 miles still farther north.

Jan 1, 1932

By H. H. Gardner

Introduction The Greenhill mine of West Canadian Collieries, Limited, is on the Alberta side of the Crowsnest pass, twelve miles from the Alberta British Columbia boundary-line. Here, five coal seams of Lower Cretaceous age are found in the Kootenay formation. They outcrop on the north and south slopes of the valley, with strike approximately N.30°W., paralleling the main range of the Rocky mountains, and dip about 40 deg. westward. Of the five seams, only two, designated No. 1 and No. 2, have been worked to date. On the West Canadian Collieries property, No. 1 seam ranges in thickness from thirty feet to nil. Generally, it has a hard, strong conglomerate roof. No. 2 seam is separated from No. 1 by forty-five feet of shales and sandstones. It has a thickness of eight to thirty feet.

Jan 1, 1947

By Hans D. Gougar

To meet an increasing demand for minerals, mining operations are moving to ever more remote regions. The lack of a local energy supply and infrastructure, coupled with social and regulatory demands for lowered environmental impact of mining operations, presents an opportunity for a seemingly unlikely competitor ? a nuclear power plant. The Modular Pebble Bed Reactor concept, currently in various stages of research and development around the world, offers a high degree of reliability and safety with minimal consequences for the local or global environment. The passive safety features of this design eliminate the need for the extensive active safety systems that add significantly to the cost of current water-cooled reactors. With the MPBR, as with all nuclear plants, there are no appreciable quantities of waste products released to the environment during normal operations. In contrast with conventional reactor designs, the MPBR would also remain radiologically safe even under the most severe abnormal circumstances. The key to the design is the fuel element. Enriched uranium microspheres are coated with various layers of pyrolytic carbons and silicon carbide to form a highly-temperature resistant particle that effectively retains all fission products. These particles are mixed with graphite and formed into 6 cm pebbles. A randomly packed vessel of such pebbles forms the reactor core through which helium is circulated as a coolant. Computer models and tests performed on actual pebble bed reactors confirm that fuel failure temperatures are not reached even during the most severe conceivable loss of coolant accident. The reactor drives a gas turbine cycle with resulting efficiencies as high as 48%, comparable to natural gas-fired units. The low price of uranium fuel and low maintenance requirements translates into competitive operating costs. However, high capital costs prevent the MPBR from competing with natural gas in most markets. In remote applications where no fossil supplies are readily available, the playing field is more level. This paper summarizes the features of two of the more promising candidates for remote applications and discusses the strengths of the MPBR from the perspectives of fuel supply and environmental impact.

May 1, 2002

By S. J. Buckler

Many metallurgical processes use submerged gas injection to increase the contact area between gas and liquid phases in order to promote faster overall reaction rates. The work presented in this paper is part of an experimental investigation to measure the gas-liquid interfacial area available in bubble plumes within molten metal baths. Measurements of the nitrogen absorption rate during submerged injection into molten iron baths have been used to estimate the interfacial areas of the bubble plumes. A theoretical model was used to predict the superficial nitrogen transfer rate under mixed liquid phase mass transfer -interfacial reaction control. The interfacial area was calculated by dividing the overall nitrogen absorption rate by the superficial rate. Reasonable agreement was obtained between the interfacial areas measured in our laboratory with data from a comparable system reported in the literature. The experimental results were compared with the predictions of three theoretical models and one empirical correlation. The models of Turkdogan (3) and Zhao and Themelis (5) gave the best agreement with our data.

Jan 1, 2004

By R. J. McCarthy

In-pit Crushing and Conveying (IPCC) is increasingly being considered by mining companies as a means to reduce their dependence on trucks and thus, fuel, tires, labour, etc. There is potential for great savings in operating costs which ultimately can mean better economics for a mining project. Vale has considered the application of IPCC at its Moatize coal project in Mozambique. Up to three studies have been conducted with the latest, at a pre-feasibility level, showing some promise. This paper explores the mine planning and IPCC engineering elements required in an IPCC study, their application to the Moatize project, and the drivers which most impact the viability of IPCC at Moatize.

Aug 1, 2013

By Gary M. Bone

The autonomous control of vehicles interacting forcibly with their environment, such as dozers and tractors, is an unsolved and challenging problem. Forces and motions are inherently coupled between the tool and the means of vehicle propulsion. Furthermore, they are often operated within uncertain and unstructured environments, such as those encountered in underground mining. There is a growing industrial interest in the development of robotic vehicles to improve productivity, efficiency and safety in mining and construction. This paper focuses on the modeling and control of autonomous robotic dozing for a material removal operation. A dozing process model has been developed based on observations of both a fullscale dozer and a scaled-down version. The model characterizes the dynamic interactions between the blade position, material accumulation on the blade, material distribution in the environment, and the motions of the dozer. The dozing control objective is to remove the loose material as rapidly as possible by driving forwards at full power while automatically raising/lowering the blade in response to sensor measurements. Two different controllers were developed to meet this objective. The first controller is based on a set of heuristic rules, and the second is an optimal controller based on the dynamic model. An instrumented scaled-down robotic dozer and dozing environment, designed to emulate the full-scale operation, are used to implement the controllers and compare their performances over multiple dozing passes. Experimental results are presented showing that the model-based controller increased the material removal rate by 33% compared to the rule-based controller. Lastly, technologies for full-scale implementation are discussed, followed by proposed future work and conclusions.

Aug 1, 2013

By C. I. Walker

Field tests at a number of large mineral processing operations have been undertaken to better understand the wear life impact of different aspects of pump design, materials of construction and maintenance procedures. Data are presented for wear rates, and typical result variability is explored. To improve the availability of pumping equipment in a milling circuit it is not only important to improve the wear life, but also reduce the variability in the wear life of components so that the incidence of premature failure is lessened. Localised gouging wear due to flow separation and turbulent eddy formation is often the point at which part-holing occurs. A number of improvements to the design of pump impeller and throatbush (suction side liners) to reduce the localised gouging wear are outlined. Also, results are presented on the use of composite materials (mix of metal, rubber and ceramic) for throatbush materials to protect specific areas against wear.

Jan 1, 2012

By G. G. Li

"A dynamic ventilation-modeling package, VREX, was used to simulate the mine activities through tracking the equipment movements in underground workings and determine the airflow demand for a new production scenario in a ventilation-on-demand (VOD) system. It incorporates the mine development data from a discrete event simulation and balances the ventilation network using the CANVENT ventilation solver. A case study was performed to demonstrate the capabilities of the software, evaluate the performance of the network and determine the potential energy savings for implementing VOD in a deep mine operation.INTRODUCTIONThe ventilation cost of an underground mine can be significant—up to 50% of the mine’s energy consumption could be used to run fans and provide heat/refrigeration to meet the specified production environment for workers and equipment. The VOD system has proven to be more efficient in operating the fans and supplying the amount of air corresponding to the mine activities taking place in underground workings (Hardcastle, Kocsis, & O’Connor, 2006). In order to properly solve and evaluate the VOD system, a dynamic ventilation modeling software VREX—the ventilation rules engine has been developed to simulate the mine activities and determine the airflow demand for each production scenario within an operation period (Dasys & Cameron, 2011).VREX is a decision support tool, backed by the CANVENT mine ventilation solver (Li, Kocsis, & Hardcastle, 2009), for determining the outcomes of network configuration changes over time. The software incorporates the mine development data with ventilation modeling through the discrete event simulation (DES) performed by SimMineTM. As it simulates the air requirements for different vehicles and activities, VREX can evaluate both the performance of the ventilation system and the potential economic benefits of making operational or technological changes (Pritchard, 2010). For example, the model can be used to assess the economic and environmental impacts arising from modifying regulations to support the use of electric or lower emission vehicles. The combination of DES and ventilation modeling provides a new technology to generate the production scenarios according to mine schedules and activities and to determine the potential benefits for various levels of ventilation control, such as time interval and work shift change."

Jan 1, 2019

By G. V. Poropat

Roughness of a discontinuity may be an important factor influencing shear strength of the discontinuity. Traditionally, determining the roughness of a discontinuity surface and providing a numerical measure of the roughness has required considerable effort or specialised equipment. The development of new 3D imaging tools that are easy to use has provided effective fast and accurate means of creating 3D surface models from which roughness measurements can be readily obtained. These new techniques are versatile enabling a user to measure roughness along any desired profile and at any resolution up to the limit of the spatial subtense of a measurement on the discontinuity surface. This paper primarily reviews extensions to the use of 3D imaging that enable the measurement of roughness. Additionally we provide some examples of the measurements and examine some of the issues associated with extracting measures from the spatial data that will support estimation of shear strength.

May 1, 2009

By D. K. Sarkar, Jiawei Xiong

"Self-assembled monolayers (SAM) on the aluminum substrates are used as the adhesion promoter between two aluminum substrates when bonded with the adhesive in adhesive bonding technology. Traditional surface analysis tools are not capable of identifying the presence of SAM on a surface; therefore, EIS has been used to determine their presence on the aluminum substrates. In this study SAMs have been deposited on aluminum using the monomer of (3-Glycidyloxypropyl)trimethoxysilane (GPTS) organosilane. AA6061 aluminum alloys substrates were chemically cleaned with NaOH and HNO3 to remove the native oxides, followed by immersion in silane solutions. In a second method, SAMs were prepared by applying a spin coating of silane solution to the samples. The prepared SAM coated aluminum samples were analysed by EIS in the three electrode corrosion cell using a diluted alkaline solution. The impedance of the SAM coated aluminum is found be higher than the as-received aluminum. It has been also observed that the open circuit potential (OCP) of the SAM coated aluminum is higher than the as-received aluminum. Both elevated values of the impedance and OCP confirm the presence of SAM on aluminum.INTRODUCTIONSelf-assembly (Schreiber, 2000) is defined as the spontaneous formation of complex hierarchical structures from pre-designed building blocks, typically involving multiple energy scales and multiple degrees of freedom. Generally speaking, SAMs are created by the chemisorption of ""head groups"" onto a substrate from either the vapor or liquid phase followed by a slow organization of ""tail groups"" of a molecule. Typically, head groups are connected to a molecular chain in which the terminal end can be functionalized with groups such as –OH, –NH2, –COOH, or –SH to vary the wetting and interfacial properties (Chauhan et al., 2007; Ulman, 1996; Vashist, Lam, Hrapovic, Male, & Luong, 2014). Though there exist several methods to prepare SAM (Chauhan et al., 2007; Chen, Yang, & Zhang, 2014; Cho, Park, Jon, & Choi, 2007; Igor Luzinov, 2000; Reis, de Melo, & Costa, 2006; Song, Zhai, Wang, & Jiang, 2006; Sugimura, Hozumi, Kameyama, & Takai, 2002; Vashist et al., 2014), the two methods vapor phase (Song et al., 2006; Sugimura et al., 2002) and solution(Chen et al., 2014; Igor Luzinov, 2000) are commonly used. Recently, many articles have been published on the fabrication of superhydrophobic surfaces with SAM technology (Cho et al., 2007; Pan, Shen, Shang, & Xing, 2012; Siddaramanna, Saleema, & Sarkar, 2014; Song et al., 2006). Brassard, Sarkar, and Perron (2011) successfully obtained a superhydrophobic film by applying fluoroalkylsilane via self-assembly on monodispersive silica. SAMs are also reported as good candidates for anti-corrosion and adhesion promotion (Chen et al., 2014; Saleema, Sarkar, Paynter, Gallant, & Eskandarian, 2012). However, papers on the characterization of SAM properties are rarely seen. The most commonly used substrate for SAM is silicon and the method implemented is scanning probe microscopy (SPM) such as atomic force microscope (AFM) (Igor Luzinov, 2000; Moores, 2011; Zhang, 2003, 2005). Igor Luzinov (2000) analyzed the epoxysilane SAMs’ surface morphology and microstructure properties using scanning probe microscopy (SPM) and ellipsometry on single-crystal silicon wafers. SAMs have been used to improve the adhesion bonding of aluminum or plastics but no characteristic data have been presented yet (Saleema et al., 2012; Telegdi, 2007; Wang, Xu, Luo, Wang, & Wang, 2009). Recently, Reis et al.(Reis et al., 2006) have studied SAM of alkane diphosphonate (Gardobond X4661) on Al 5052 alloy samples by EIS in a naturally aerated sodium sulfate solution."

Jan 1, 2016

By M. A. Vos

"Aggregates are the low-cost mineral raw material of building construction. Large volumes of aggregate are consumed each year. The availability of aggregates in southern Ontario is discussed in the context of the geological formations in which they occur. Sand and gravel are abundant in glacial deposits and in recent sediments. A knowledge of the glacial history is important for their discovery. Bedrock formations provide a variety of aggregates in Ontario. Knowledge of the rock types involved and of the depth of overburden are important for evaluation of the aggregate potential of bedrock resources in an area. Utilization of available resources intensifies as the population increases. Urban development makes it progressively more difficult to satisfy the demands of the construction industry. The effects of urban development on the aggregate resource base of an area are illustrated by developments and consumption statistics in the Toronto- centred region. There is an obvious need for a comprehensive survey of available resources in urban areas to serve as a guide in land-use planning. To fill this need, staff members of the Industrial Minerals Section, Geological Branch, Ontario Department of Mines and Northern Affairs, are engaged in mapping projects and mineral resource studies in southern Ontario as well as in some urban areas of northern Ontario."

Jan 1, 1972

By A. Bezama

For over a decade European countries have addressed contaminated sites by developing technologies for managing both polluted soil and groundwater. This development has not only been driven by health and environmental aspects, but also because of economic pressures, as the remediation and redevelopment of derelict areas can be a meaningful alternative to undeveloped areas for the establishment of new industrial, recreational, housing and service locations. In most developing countries, however, the subject of contaminated sites is a new environmental issue that authorities have recently started to deal with. Among these countries, Chile has just started to prepare the country's legal context as well as to foster the formation of research and investigation groups that will deal with the exploration, investigation and management of contaminated sites. That requires a comprehensive technical, scientific and legal support in this stage. Goal of this article is to present the state-of-the-art technologies for site remediation currently applied in industrialized countries, in order to identify the most interesting approaches that can be implemented within the Chilean situation, especially considering the influence of the copper mining industry on the soil and groundwater quality of the environment surrounding their production facilities.

Jan 1, 2007

By J. P. Norrie

The presence of copper-bearing rocks in the Coppermine River area of Arctic Canada has long been known. Word of this was probably circulated along the Arctic and Hudson Bay coasts by the Eskimo, who no doubt traded articles made from native copper among themselves. It is not known whether any of these ever reached the southern shores of Hudson bay. The Indians, also, knew of the occurrence of copper here, as they served as guides to Hearne when he made a successful trip over land from Hudson bay to the Coppermine river. The possible commercial importance of these copper deposits was early appreciated by the Hudson's Bay Company, who on December 7th, 1770, despatched Samuel Hearne from Fort Prince of Wales, now Fort Churchill, to investigate them. He reached the then unnamed river at a point forty miles from its mouth on July 14th, 1771, and after surveying the river to its mouth and naming it the Coppermine, he retraced his steps to Fort Churchill by an overland route. Hearne's expedition was probably the most remarkable and arduous ever attempted in Arctic exploration, but the actual value derived from the trip was entirely out of proportion with the hardships he must have suffered. He verified the occurrence of native copper, but his astronomical and other observations were of little value. Until 1912 no concerted effort was made to obtain any definite information as to the geology and economic value of the Copper-mine deposits.

Jan 1, 1931

By L. V. Bell

"The gold deposits of the Caribou mine are representative of those of the Province of Nova Scotia as a whole. The ore shoots within the deposits, in common with those elsewhere within the Province, are associated usually with interruptions or irregularities in the broader and uniform fold structures. The structural factors localizing ore deposition as applied more specifically to the Caribou mine are demonstrated chiefly by the close relationship of the two principal ore shoots, known as the main orebody and the 'high-grade' vein, with a pitching drag fold developed in the southeast limb of the major northeast-southwest trending anticlinal fold or elongated dome that constitutes the primary structural feature of the Caribou gold district. It is of interest to note that the evidence indicates that this drag fold, in common with other folds subsidiary to the primary fold, formed as a result of movement similar in nature to that which caused the primary fold itself. Presumably, therefore, these folds are coincident in time.The property described here as the Caribou mine is an amalgamation of two adjacent properties formerly known as the Ross and the Nova Scotia Gold, but which since 1934 have been controlled and operated as a unit by The Consolidated Mining and Smelting Company of Canada, Limited. The Caribou mine is situated in the Caribou gold district about 45 miles to the northeast of the city of Halifax and about 6 miles to the north of the Moose River gold district.The history of mining at Caribou dates back to 1867. The first recorded gold production is for 1869. From 1869 to 1933 the gold produced from the mines of the Caribou district aggregated 47,249 oz. from 93,234 tons of ore treated. The grade of the ore on the basis of the gold actually recovered from the district would thus average 72 oz. gold a ton, which, as will be noted from the following, is precisely the grade of the ore treated from the Caribou mine during operations by The Consolidated Mining and Smelting Company. These operations commenced in September, 1934, and milling on a commercial basis was under way during 1938. Since that time production, apart from a short period in 1945 during which efforts were concentrated on development work, was continuous to early in 1947, when the mine closed down owing to exhaustion of the known orebodies. Gold produced from the Caribou mine by The Consolidated Mining and Smelting Company from September, 1934, to the close of 1946 aggregated 43,205 oz. from 90,754 tons of ore milled; the grade of ore treated averaged 0.50 oz. gold a ton. The indicated average grade of O.S oz. gold a ton for the ore of the Caribou district throughout its mining history ranks somewhat higher than the 0.37 oz. a ton average for the ore milled to date from the several gold districts throughout the Province as a whole according to the production statistics of the Provincial Department of Mines."

Jan 1, 1954

By C. Larsen, R. A. Walker, A. Voth, C. Daoust

"The 3000 t/d mill at Hernia Gold Mines Inc. was commissioned in March, 1985. By Canadian standards the concentrator is highly automated, however, unlike the retrofit systems in many other plants, the Hernia process control system was installed during plant construction. This paper describes the Hernia control system beginning with system development (justification, architecture, start up, etc.), proceeding to current applications (crushing, grinding, leaching, etc.) and finally discusses some of the short term objectives for system improvement.INTRODUCTIONThe Hernia Gold Mines Inc. operation is located in the Marathon area of Northwestern Ontario. Controlled by Noranda Minerals Inc. (50.1 %), the cost of bringing the mine into production was nearly $300 million. A unique feature of the mine development was the extraordinarily short elapsed time of three years from Noranda's initial involvement to the start of milling operations. Additional background information on this project can be found in the trade literature (e.g. Tinter (1986). Scales (1987).)The Hernia concentrator is designed to process 3000 tpd of ore and commenced operation in March, 1985. Figure 1 provides a general plant flowsheet indicating the major circuits. Typical annual production statistics are included on the figure and these have been extrapolated from the available 1987 year-to-date data. Larsen and Tessier (1986) have previously described the operational aspects of the mill.In a metaphorical sense, the Hernia concentrator is like the traditional bride, ""wearing something old (e.g. the cyanide leach process), something new (e.g. a plant wide digital control system installed during construction), something borrowed (e.g. crushers from Gaspe) and something blue (e.g. the cladding on the surface buildings). While the prospect of fully undressing this bride is of considerable interest, here we choose to focus on something new. In particular, we choose to examine the process control system in some detail since Hernia is one of Canada's more highly autcmated gold mills. The control system is of interest because it has received suostantial credit for maximizing metal production and minimizing operating costs. With reference to the latter, it is worthy of note that Hem lo reports recent operating costs of less than $100 U.S./oz."

Jan 1, 1988