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By G. Favini

A Bayesian decision model of minimun risk, based on the probability and costs of mine discoveries and non-economic projects, is presented for massive sulphide exploration in the Canadian Shield. The sample used for the model is composed of data relating to forty mines, sixty non-economic sulphide occurrences, and sixty occurrences of graphitic and pyritic material. These economic and barren samples consist of drill-tested occurrences which were, in varying degree, characterized by conductivity anomalies. Given the large size, the reliability and the homogeneity of the data base available for massive sulphide exploration, it is shown that certain statistical models can and should be utilized as a tool for decision-making by explorationists. Given this data base, information theory tells us that only those signals that are independent of one another will transmit information with minimum error. An ensemble of six significant multilevel signals, markedly independent of one another and consisting of numeric and geometric form descriptions derived from Bouguer anomaly, aeromagnetic and physiographic maps, were identified and evaluated by case studies. The use of these signals as input in a simple statistical procedure, or in a carefully planned and experienced visual appreciation scheme, can be of significant aid in decisions concerning the choice of favourable areas or sectors to explore in detail. The method of discriminant analysis is theoretically and practically suited for the statistical modelling involved. By way of a simulation on our statistical model, the efficiency of the model and of the underlying criteria is determined for historic cases and, by inference, for its validity in future exploration. An approximate optimized solution is derived from the model which suggests that over 90% of the known ore could be found by screening, according to a model such as that herein described, and drilling only 30% of the targets (mostly barren) normally identified and tested in current and past exploration.

Jan 1, 1979

By J. A. Brothers, M. R. Foran

"AbstractThis paper reviews the progress made in the manufacture of hydraulic cement from iron blast-furnace slag by simply grinding the granulated material with other constituents. The influence of the chemical and mineralogical composition of the slag, the conditions of granulation, the manner of drying, and the fineness of grinding, on the hydraulic properties of the cement, is discussed. The effect of additions of lime, portland cement, and anhydrite, alone and in combination, on the physical and cementing qualities of the mortar and concrete made from Sydney blast furnace slag, is shown in tables of data and is reviewed in some de- tail. The work at the Nova Scotia Technical College has shown that a cement equivalent in every respect to portland cement can be made from basic blast furnace slag- by the us2 of certain quantities of portland cement as an activator.IntroductionBlast furnace slag is a potentially valuable material for the manufacture of hydraulic cement. It is a by-product of the manufacture of iron in the blast furnace, and is formed by the combination of the silica and alumina .of the iron ore with the limestone flux. The metallurgist terms a slag .acid or •basic according as the percentage of lime is less or greater than the percentage of silica plus alumina. The basic slags have the •more pronounced hydraulic properties."

Jan 1, 1950

By E. Dernedde

Industrial plants located in the province of Quebec, Canada, are subjected to large variations of the ambient air temperature, Building ventilation systems of these plants must have some flexibility in order to meet industrial hygiene standards (TLV for chemical substances, heat stress and cold stress) at any time of the year, The building ventilation of a bath treatment plant of an aluminium smelter in Quebec was examined under summer and winter conditions, Part of the plant has periodic emissions of hydrogen fluoride gas and heat from hot anode butts, CFD modeling was used to optimise the building ventilation of the bath treatment plant, The present study proposes a modified building ventilation system, which improves the internal environment, complies with industrial hygiene standards and also reduces heating costs by 20 % during winter.

Jan 1, 2005

By U. Erb, L. Monaco

"Electrodeposited nanomaterials are increasingly implemented in advanced industrial applications in the aerospace, automotive, defence, electronic and energy sectors due to their outstanding physical, chemical and mechanical properties, including increased strength and wear resistance, and superb magnetic properties. As with the development of any class of new materials, the corrosion behaviour of these electrodeposits requires considerable attention. This presentation reviews major developments in the understanding of the corrosion behaviour of nanocrystalline metals, alloys and metal-matrix composites over the last 20 years, with emphasis on how their intrinsically high density of intercrystalline defects does not compromise their corrosion resistance as initially expected.INTRODUCTIONOver the past 20 years there have been considerable advances in the understanding of the corrosion behaviour of nanocrystalline metals, alloys and metal-matrix composites. In this paper, the corrosion properties of nanocrystalline nickel, cobalt, zinc, and copper and some of their alloys are reviewed with emphasis on how a reduction in grain size affects their corrosion behaviour in different environments.It is possible to synthesize nanocrystalline material with microstructural refinement down to the range of 1 to 100 nm using a large number of processing methods. There are five basic synthesis methods that can be used to classify the different techniques: vapor-phase processing, liquid-phase processing, solid-phase processing, chemical synthesis, and electrochemical synthesis. Depending on the synthesis method, different microstructures (equiaxed, textured), shapes, and forms (films, particles, bulk material) may be produced. In addition, other factors may be introduced (eg. residual porosity or amorphous phases), aside from microstructural refinement, which can contribute to the observed properties (Erb, 2010). In order to interpret and categorize the resulting microstructures, a dimensional structure modulation scheme was introduced by Siegel (1996) in which zero-dimensional nanomaterials refer to individual particles, clusters, etc. One-dimensionality results from a layered (less than 100 nm thick) structure. Two-dimensional nanomaterials are thin, layered structures containing grains (less than 100 nm) within each layer. Finally, three-dimensional nanomaterials are bulk structures with an average grain size less than 100 nm."

Jan 1, 2012

By John H. Fowler

"Most of the aggregate used in Nova Scotia is produced from numerous glaciofluvial and ice-contact deposits scattered throughout the province. Production from bedrock sources is increasing, with most of the coarse aggregate used in the Halifax-Dartmouth area coming from quarries operating within the metro area.A recently completed provincial sand and gravel inventory mapping program has identified some ""resource-poor"" areas where comprehensive aggregate evaluation programs are underway. Although some areas of the province are experiencing aggregate supply problems, large volumes are exported to markets as far away as Bermuda.IntroductionThe Nova Scotia Department of Mines and Energy has been involved with aggregate resource studies for several years, although sand, gravel and crushed stone are not designated as minerals under the Mineral Resources Act of Nova Scotia. Our role has been to provide the aggregate industry with resource data as well as provide similar information to governmental agencies involved with municipal planning, water resource studies and environmental protection regulations. Several private consulting firms use the information in many of their site development studies.We became involved with aggregates in a rather roundabout way. Several years ago, an outcry from inhabitants of a small coastal community over the removal of sand and gravel from a local beach moved the provincial Department of Lands and Forests to take action to protect provincial beaches. We were asked by the Department to provide information and to suggest alternative sources here operators extracting sand and gravel from beaches could relocate. This request initiated an aggregate inventory survey in southeastern Cape Breton, which was later extended to cover the entire province. The initial provincial sand z and gravel inventory survey provided a series of 1:50,000 maps showing the distribution of sand and gravel deposits in the province."

Jan 1, 1982

By Francis Chartrand

The Kwyjibo deposit is an iron oxide Cu-REE-F-Mo-Au mineralization of Mesoproterozoic age located in the Grenville Province approximately 120 km NE of Sept-Îles, Quebec (Figure 1). Occurring along the SE margin of the Canatiche granitic complex, the deposit is composed of several polymetallic showings that are related to different textural facies of magnetite. The mineralization process at Kwyjibo is complex, and is divided into Early Granitophile, Magnetite, Main Polymetallic and Specular Hematite stages (Cayer et al., submitted for publication). The Main Polymetallic stage, comprising chalcopyrite, pyrite, fluorite, molybdenite and REE-bearing minerals, is superimposed on pre-existing magnetiterich rocks. Discovered by SOQUEM Inc. in 1993, the Kwyjibo deposit shares many characteristics with other hydrothermal polymetallic iron oxide deposits around the world. Foose and McLelland (1995) suggested that this class of mineralization could occur in the Grenville Province. However, only a few polymetallic occurrences are known to be associated with low-Ti iron oxide deposits in the Grenville. Kwyjibo is one of the most significant examples of a polymetallic iron oxide deposit to have been found in the Grenville Province to-date.

May 1, 2003

By R. A. Wyman, F. E. Hanes

THE demand for high-quality aggregate is increasing in all phases of the construction industry and in all organizations associated with road building in Canada. The production of aggregate in Canada has increased almost continuously since the end of the war and has quadrupled since 1948. Increases during the past fifteen years can be accounted for by the expansion in all types of construction, particularly that of roads and highways. Total construction in 1959, based on preliminary estimates, has been valued at $7 billion, and an increase fore-cast for 1960 indicates optimism on the •construction horizon (1). Cement produced in Canada in 1959 amounted to 6.3 million tons. This is more than 2.5 times the 1948 production. Increased cement production indicates an increased use of concrete, and thus an increased need for aggregate. Natural sand and gravel deposits are gradually being depleted.

Jan 1, 1962

By C. O. Stee

IN the October, 1936, issue of the Canadian Mining Journal there was published a series of very comprehensive and exccellently illustrated papers by Mr. C. O. Stee and members of his staff dealing with Siscoe operations and ore-bodies. These were, in the order in which they appeared: Geology of Siscoe Gold Mine, by O. L. BACKMAN Diesel Power at Siscoe Gold Mines, Ltd., by C. O. STEE andE. A. BLOMQUIST Mining at Siscoe, by L. T. POSTLE and W. F. Engineering and Surveying, Siscoe Milling Practice, Research and Testing Laboratory, Assaying of Mill Tails and Solutions, BROWN(6) by P. A. TEEPLE (7) by L. E. DJINGHEUZTAN by L. RIVETT (8) by G. IRWIN (9) The Editor of the Canadian Mining Journal cordially assented to our suggestion that these papers be reviewed at the 1937 Annual General Meeting of the Institute, and the authors very kindly accepted our invitation to present such reviews . Of these courtesies, full acknowledgment is here accorded. To our readers, we commend the original papers in the Canadian Mining Journal. The summaries presented at the meeting follow. EDITOR. THE GEOGLY OF THE SISCOE MINE The Siscoe gold deposits lie in and near a stock of granodiorite, related to the Bourlamaque batholith, which has intruded highly folded Keewatin volcanic rocks .. The volcanic rocks lie to the north of a belt of Timiskaming sediments.

Jan 1, 1937

By M. E. Hurst

SINCE 1934 there has been a marked revival of interest in the Porcupine district, especially in the eastern portion of the area, where exploration on the property of Pamour Gold Mines has indicated the presence of extensive gold-bearing deposits. Owing to the prevalence of overburden and the limited amount of exploratory work that has been done, little information is available as yet concerning the distribution and structural relationships of the rocks in the area to the east of Porcupine lake. In order to throw some light on the structural conditions in this section, a brief discussion of the sequence and character of the formations in the better known, producing section of the camp has been included. It should be emphasized that this paper is a preliminary study and that, consequently, the conclusions expressed should not be regarded as final. The writer wishes to acknowledge his indebtedness to P. C. Benedict, whose study of the geological relationships on the Foley-O'Brien property has made possible a fuller understanding of the structure in the central portion of the area. The writer also wishes to express his appreciation of the information and facilities placed at his disposal by R. M. Macaulay and C. D. Stevenson, of Pamour Gold Mines, and by A. Bell, of Noranda Mines, Limited.

Jan 1, 1936

By Shuji Owada

Scrap electrical and electronic appliances, so called "E-waste", are not a present target to be collected and recycled under Japanese regulations. This material, however, contains considerable amounts of base, precious, and rare metals and it is necessary to recover these elements for maintaining stable supply and establishing "the society of environmentally-sound material-cycle". This paper describes recent trends of rare metals recycling in Japan and technological approaches to achieve the above objective. Also a research work to concentrate rare metals from the printed wiring boards by combining brand new comminution and physical separation methods is discussed.

Jan 1, 2011

By Gordon MacVean

The object of this paper is to present for your consideration some of the present-day trends of safety practice in the coal mines in the United States and Canada. Coal mining at its best is a hazardous occupation. Men must be experienced miners in order to appreciate the existing hazards and must remain ever conscious of them if they are to work safely. The question is often asked whether our efforts for increased safety are showing results. So often it appears that strides are made for a period of a few years in the reduction of fatalities and lost-time accidents only to have all ground lost by an unfortunate year, after which progress is commenced again only to have a repetition of the same thing. Table No. 1 is an answer to this question. It shows the fatality rates over the last two decades in the coal mines of the United States and Canada. These are given in divisions of five years. The general trend is noticeably downward, exceptions being due to explosions or disasters which claimed an unusually heavy toll of life. These last are certainly not as common today as they have been in the past. It is only reasonable to suppose that this trend towards a lower fatality rate is the result of well directed safety effort. Reliable statistical organizations have offered figures to the effect that only 15 per cent of all accidents can be eliminated by the use of mechanical safeguards. The state of mind of the man involved, or his attitude towards safety, commonly called 'safety-consciousness,' is the controlling factor in the prevention of 85 per cent of our accidents.

Jan 1, 1931

By Jan E. Nesset, Julie Fournier, Jorge Torrealba, Colin Hardie

"Gas dispersion studies have been used to benchmark and optimize plant flotation performance for more than a decade, although this technology is not as widely in use as it likely should be based on the significant improvements that have been reported. Part of the reason may be a general lack of awareness within the industry of just what these improvements have been. This paper reviews a number of the reported case studies, groups them into categories of improvement, and draws some general conclusions. The paper will be of interest to plant engineers and technology providers seeking new approaches and tools for improving their own and clients’ processes.INTRODUCTIONThe sector of flotation hydrodynamics that is now known as gas dispersion technology, and the corresponding terminology, had its beginnings in the 1980’s and early 1990’s in the laboratories of McGill University where the students of Prof. J.A. Finch and Dr. C. Gomez conducted studies of gas holdup, superficial gas rate and water recovery on laboratory flotation columns (Laplante et al., 1983; Xu et al., 1991;, Banisi and Finch, 1994; Finch et al., 1999; Nesset, 2011). Sensors were developed for gas holdup (eg), gas rate (Jg) and bubble size (Db) distribution (Tavera et al., 1996: Finch et al., 1999; Dahlke et al., 2001; Chen at al., 2001; Hernandez-Aguilar et al, 2002, 2005). The sensor measurements were rapidly adapted for use in mechanical flotation machines in plant environments (Gomez and Finch, 2002; Gomez et al., 2003; Cooper et al, 2004; Torrealba-Vargas et al, 2004; Nesset et al., 2007). Somewhat parallel developments were being conducted by Gorain and colleagues at the University of Queensland’s JKMRC on pilot and industrial flotation machines using the McGill approach but utilizing alternate sensor designs for eg, Jg and Db (Gorain et al., 1997, 1999; Schwarz and Alexander, 2006) to link flotation kinetics to bubble surface area flux (Sb). Early industrial applications were those led by the university teams from McGill (Canada), the JKMRC (Australia) and the University of Santa Maria (Chile) at plants in North and South America, Australia, South Africa, Asia and Europe. Industrial organizations that brought the technology on-board in the early 2000’s included Teck Resources (then Teck Cominco), COREM, Vale (then Inco), Anglo American Platinum. Several of the major flotation cell manufacturers also purchased the McGill bubble viewer technology for their own equipment studies. The sensors have continued to evolve with multiple and continuous measurement of Jg (Torrealba-Vargas and Finch, 2006, Bartolacci et al., 2008), gas holdup by acoustic means (O’Keefe, 2007) and a combined Jg-Db device called the Anglo Bubble Sizer (Harbort and Schwarz, 2010). A review of the gas dispersion technology use and development have been provided by Gomez and Finch (2002), Harbort and Schwarz (2010) and Nesset (2010)."

Jan 1, 2015

By P. W. Jensen

Gold deposits in Interior Alaska are commonly coincident in time and space with reduced, mid-Cretaceous granitoids. The True North deposit of the Fairbanks district is several km from such granitoids, but yields mineralization ages indistinguishable from the Fort Knox granite-hosted deposit. True North, however, resembles sediment-hosted epithermal Au, demonstrating the variability of intrusion-related Au deposits in metamorphic rocks. The True North deposit (14M tons at 1.5 gpt) is hosted within a carbonaceous thrust complex separating eclogite facies from amphibolite facies rocks, located > 5 km from mineralized granite outcrops. The ores contain anomalous Sb, As, and Hg (stibnite is the most common sulfide) with ankerite-sericite alteration in steep NE-striking ?feeder? shears and low angle thrust shears. Nearest hornfelsed rocks are located > 1 km away, and across several high-angle faults. Fluid inclusion data indicates trapping temperatures of ~250C from low-density, low-salinity fluids at P < 0.5 kb. Au was originally present as solid solution in sulfides; minable ores are restricted to the oxidized upper 100 m of the deposit. The considerable differences between this deposit and the temporally equivalent Fort Knox intrusion-hosted deposit indicate no one description adequately characterizes this deposit type.

May 1, 2003

By Scott A. Trebilcock

Nautilus Minerals Inc the world?s leader in exploration and development of deep ocean mineral resources is today focused on the recovery of high grade copper-gold from in seafloor massive sulphide mineralization. These mineralized belts, analogous to land based volcanogenic massive sulphides (VMS) deposits are located near tectonic plate boundaries of the Western Pacific and around the world. Nautilus; first development project is Solwara 1 located in benign waters in Papua New Guinea. Since 2006 the company has completed detailed environmental and geological studies at Solwara 1, culminating in a number of world firsts, including the first Environmental Permit for a deep ocean mineral project and the first NI 43-101 compliant seafloor massive sulphide resource statement. Nautilus has relied heavily on proven deepwater technologies from the oil and gas industry in the design of the first mineral extraction system. Pipeline trenching units, workclass ROVs, deepwater production risers and drill cutting removal systems will all be adapted at Solwara 1. Key contractors to the project have all been selected for their deepwater experience, creativity and determination to launch this new industry. Innovation is at the forefront of Nautilus? success to date. This paper gives an overview of the Solwara 1 development and describes the exploration and production technologies adapted for seafloor mineral extraction.

May 1, 2010

By M. B. McClenaghan

"This paper summarizes diamond exploration techniques used in glaciated terrain, focussing on indicator mineral and geochemical methods applied to glacial sediments. Understanding the ice flow history, depositional history, and stratigraphy of glacial sediments is essential to successful sampling, interpretation and follow-up of indicator mineral and geochemical anomalies related to kimberlites. Kimberlite indicator minerals survive glacial transport over long distances and the relative abundance of each mineral in till is a function of the primary mineralogy of individual kimberlites. Indicator mineral distributions observed at a regional scale define the net effect of glacial dispersal, often along different ice flow directions. Local-scale distributions define individual dispersal trains. The medium sand (0.25 mm to 0.5 mm) fraction of heavy mineral concentrates, * GSC Contribution No. 2002028 prepared from glacial sediment samples, is best suited for indicator mineral surveys. The application of till geochemistry to diamond exploration is increasing because it is significantly cheaper than indicator mineral analysis and it can be performed quickly. The <0.063 mm (silt+clay) and 0.5 mm to 2.0 mm (coarse sand) fractions provide the best geochemical contrast between background and kimberlite-rich till. Kimberlite pathfinder elements that provide good contrast include Ni, Cr, Ba, Co, Sr, Rb, Nb, Mg, Ta, Ca, Fe, K, Ti and LREE, the relative importance of which will depend on kimberlite composition and that of the surrounding bedrock.IntroductionIn Canada, glacial erosion is the principal means by which kimberlite and its associated minerals have been dispersed, from a few tens of metres to tens of kilometres down-ice. Post-glacial weathering has had little impact on kimberlite debris in the glacial sediments, thus boulder tracing, indicator mineral methods and trace element geochemistry of the fine fraction of till (“drift prospecting” methods) can be used to detect kimberlite dispersal within areas covered by glacial sediment. This paper provides a summary of drift prospecting methods for kimberlite exploration in glaciated terrain, and includes examples of reconnaissance- , regional- and local-scale kimberlite indicator mineral and till geochemical distribution patterns.Weathered kimberlite is more susceptible to glacial erosion than the surrounding bedrock, thus many kimberlites in glaciated terrain are found in low or swampy ground, under small lakes, or covered by thin (< 1 m) to thick (>50 m) glacial sediments. Glacial erosion has removed varying amounts of the pre-glacially weathered kimberlite and, in some cases, the hard competent kimberlite below. For example, glacial erosion of the Peddie, McLean and Seed kimberlites near Lake Timiskaming, Ontario, removed pre-glacially weathered kimberlite, leaving a polished striated subcropping surface (McClenaghan et al., 1999a). In contrast, glacial erosion of the B30 kimberlite, near Kirkland Lake, Ontario (Fig.1), was much less vigorous and left a >10 m cap of soft and highly weathered dark green clay-rich kimberlite (McClenaghan et al., 1996). The thickness of remaining pre-glacially weathered kimberlite will influence the geophysical signature of the kimberlite."

Jan 1, 2002

By W. N. Roman

This paper will examine the challenges involved in ventilating and cooling South African mines, with particular emphasis on solutions to the issues of heat (generally associated with depth), mechanization and energy efficiency. Comparisons will be made with other international mining areas. Some of the deepest mines in the world are to be found in the South African goldfields. The Mponeng mine is approaching 4,000 m below surface, with virgin rock temperatures (VRT) of between 60°C and 70°C. Mining at these depths has only been possible with the use of large refrigeration plants supplying cold air, water and ice to the workings. In the Bushveld Igneous Complex, where most of South Africa?s platinum mines are located, similar VRTs are being experienced at significantly shallower depths. This is due to the different geothermal properties of the host rock between the two areas. Existing mines are being forced to go deeper and new underground mines are being planned and constructed in other areas with widely differing thermal conditions. South African metal mining has traditionally been labour intensive for historical reasons as well as for the narrow tabular nature of many ore bodies. Due to cost pressures and labour problems, some mines have been investigating the possibility of using mechanized equipment, both diesel and electric, to increase production and to improve efficiency. Studies have been carried out to determine the effect of the additional equipment on the overall ventilation system and some of the conclusions are discussed. The use of diesel equipment adds heat and pollutants to the ventilation air but, although electrical equipment has a lesser effect on the ventilation systems, it is generally less favoured due to claims of lower flexibility/manoeuvrability. Mechanization holds the promise of more concentrated mining activities but, with higher localized ventilation and cooling needs. Systems which will control the provision of air and cooling more effectively are required and are being implemented. In the 1990s and early 2000s, the South African economy experienced significant growth which was not matched by the growth in infrastructure. Consequently, at present there is a shortage of electricity generation capacity which affects large industrial consumers, including mines. Increasing levels of heat and mechanization will require more electrical energy for ventilation and cooling. There are many initiatives underway to save power or to shift consumption to periods of national low demand and these will be described.

Aug 1, 2013

By G. S. Hume

THE discovery of natural gas with naphtha in 1924 in the Upper Palaeozoic limestone of Turner Valley, 35 miles southwest of Calgary, has led to continuous developments in this field. Drilling undertaken soon after this discovery demonstrated that the anticlinal structure was in reality a major drag-fold cut off on the east side by a westerly inclined fault of large displacement. The faulted edge of the .limestone at depth determines the eastern limits of the field, which between 1924 and 1936 was shown to have a gas area 14 miles long by about 1 mile wide. Since the strata dip westerly, away from the axis of the fold, drilling becomes progressively deeper to the west and, with the advent of deeper drilling, crude oil was discovered in 1936 on the west flank of the structure but in the same porous reservoir rocks as the gas on the crest and upper parts of the fold. Since 1936, drilling has been undertaken wholly for the production of crude-oil and at present two producing areas have been found within the Turner Valley structure. The larger of these, at the south end of the field, in the vicinity of Highwood river, has a length of about 4 3/4 miles and a proved width of one mile, whereas the smaller, in the north end of the field, south of the north fork of Sheep river, has only a few producing wells.

Jan 1, 1939

By K. Barr, F. Grenier, J. Hettinger

"To reach the Hemlo Gold Inc. objective of becoming the lowest cost, safest Canadian gold producer while causing no environmental damage, management embarked from its inception on a strategy to build an organization which would foster employee involvement wherever possible. This paper describes the organizational structure and how various innovative concepts have been implemented.BACKGROUNDThe Golden Giant Mine in the Hemlo area of North Western Ontario is owned by Hemlo Gold Mines Inc. 50.1% is controlled by Noranda. The mine commenced operations in March 1985 at a modest production rate. After it reaches full production by the end of 1988, with completion of underground development work, the mine is expected to operate at 3000 t/d and produce in excess of 300,000 ounces of gold per annum. This makes it one of the three largest producing gold mines in North America.Two other companies, Lac Minerals and Teck-Corona, operate mines on either side of the Golden Giant Mine. Noranda Geco Division is located 55 kilometers to the north at Manitouwadge. The majority of Hemlo Gold's 270 employees live in Manitouwadge where a mix of accommodation was constructed and made available for purchase by employees. Bus transportation is provided to and from the workplace with modern coaches. The housing and transportation policies were implemented prior to start-up and designed to help attract and maintain good employees.As shown in Figure 1, the operation is divided into five operating and support departments with each reflecting a high degree of departmental control and responsibility. For example, the mill department is responsible for all aspects directly relating to the milling complex including safety, operation, mechanical maintenance, assaying, instrumentation, and environmental control. Similarly, the mine department is responsible for all phases of operation, mine engineering, geology, and maintenance of underground mobile equipment. The plant department is responsible for maintenance of hoisting plants and conveyances, underground stationary equipment, all site electrical services, surface buildings, housing and yard maintenance. Efforts are made at every level of the organization, from departmental organization to individual job assignments, to ensure responsibilities are clear and that they encompass complete functions."

Jan 1, 1988

By S. Rajeswari, D. Gopi

"Pitting corrosion inhibition of 304 stainless steel (SS) in groundwater with a ternary inhibitor mixture (phosphonic acid + bivalent cation + various surfactants) was studied with different environmental variables such as temperature, pH, dissolved oxygen and chloride ions. Critical pitting potential and corrosion potential were calculated for these test media using electrochemical techniques. Under the tested condition, the localized corrosion resistance of 304 SS was determined and the results are discussed. IntroductionPitting corrosion of metals and alloys is a major cause of failure in chemical processing desalination plants, scrubber for flue gas desulphurization (FGD) plants, water storage tanks and pipelines, petroleum refineries, etc.Heat exchangers and condensers in inland thermal and nuclear powerplants utilize groundwater as a coolant, but materials of construction are generally prone to localized corrosion.Localized corrosion attack can be initiated when the passive film on the metal is disrupted. The presence of certain aggressive anions such as chlorides (Cl-) can migrate to the actively corroding area and stabilize pitting corrosion. Attention has been focussed on improving the resistance of stainless steel against localizedcorrosion in aqueous environments.One of the most accepted methods of avoiding corrosion is by the addition of chemicals (inhibitors). Over the past two decades, some phosphonic acids have been explored due to their good corrosion inhibition efficiency and low toxicity (Fang et al., 1993; Karman et al., 1998; Rajendran et al., 1998; Gopi and Rajeswari, 2000a). Bivalent cations like Zn2+ are often applied as additives to inhibit the metal dissolution (Sekine and Hirakawa, 1986; Aruna Bahadur, 1998)."

Jan 1, 2003

By A. G. Lylie

Introduction At the Britannia Mining and Smelting Company&apos;s mill, the equivalent of 2,500 to 2,800 pounds of copper sulphate crystals per day is made from copper which is precipitated from the mine-water. This copper sulphate is used in the mill for the recovery of sphalerite by2 flotation. From 1932 until 1936 it was produced by exposing the precipitate to air for thirty days and then dissolving the oxidized copper with dilute sulphuric acid. In 1936, the flotation of sphalerite was discontinued and, when it was resumed in 1947, steps were taken to try to improve the former method. The present paper outlines the way in which this was done, and describes the plant and procedure by which copper sulphate is now being made, and by means of which an appreciable saving is being effected. Aboratory Tests The previous work had established that the precipitate, which consists mainly of metallic copper, must be oxidized before the copper would dissolve in dilute sulphuric acid. Various methods for oxidizing it were tried but in the early laboratory work the only suitable one found was to heat the precipitate to 600°C. and hold it at this temperature for two hours. When this was done, approximately 90 per cent of the copper became soluble in .acid. This percentage was considered satisfactory for practical purposes, but the cost of roasting was prohibitive because only a small amount of roasted precipitate was required each day.

Jan 1, 1951