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By Laurier Juteau

"NOT TOO LONG AGO, the CIM Education Committee saw the need for an information campaign to promote interest in mineral industry careers among young people. Today, times have changed and the Committee has now placed emphasis on the definition and function of the mining engineer. This situation, we believe, is entirely normal and the change of emphasis is not due to a change in the needs of the industry but more to a diversification of these needs. In years past, the Canadian mineral industry, although a very important part of our economy, was looked upon as a specialized craft and, because of the richness of our resources, did not suffer too much from competition. Now, times have changed and we are increasingly at the mercy of the competition and damaging inroads of price fluctuations, etc. We will therefore answer the questions raised in this discussion in the light of the role played in the past and the role to be played in the future by the Canadian mining engineer. We will begin with the following premises : (a) If mining engineers are to be involved in the massive problems of society, their traditional background is not sufficient. (b) Councils for professional development are working on criteria for the accreditation of advanced degree programs in the United States as well as in Canada, and, simultaneously, three-year technology programs are being developed along with professional engineering degree programs. (c) The difference between European and American industries regarding philosophy of life is that in Europe they appreciate wisdom more than HPs while in America the HP seems to be more important. The Engineering Digest of February 1972 reported that in the United States, during June and July of 1971, the second highest rate of unemployment was for the 55 to 64 age group ( 4.1 per cent). This survey certainly applies to Canadian industry as well. (d) Degrees to be awarded in Canadian universities and technical schools in 1972 will be:"

Jan 1, 1972

By R. K. Kandasami

"Naturally occurring geomaterials such as sandstone, limestone and other soft rocks, residual soils are composed of a particulates held together through a cohesive matrix, usually composed of argillaceous or siliceous cementing agents. Geo-materials such as these have been reconstituted in the laboratory using ordinary Portland cement in lieu of the naturally occurring cohesive matrix, in addition to using sand particulates. This cohesive frictional granular ensemble is an ideal model material for understanding the mechanical behaviour of transitional geomaterials such as soft rocks. An important consequence of this cohesion that pervades the inter particulate system is the enhanced tensile strength when compared to a purely granular ensemble. The assessment of strength of these soft rocks and cemented sands is often understood in the framework of continuum mechanics, i.e. considering the cemented sand to be a continuum, and performing simple elemental tests such as uniaxial compression or tension tests. A simple model to describe the behaviour of these cemented sands has been to use elements such as springs, sliders, and dashpots in parallel to describe the existence of a cohesive and frictional component of strength (Jiang et al. 2007). In the framework of continuum mechanics, the mechanical response of these cemented sands have been modeled using traditional plasticity theory, for example utilizing variants of the traditional Mohr Coulomb model, Modified cam clay (Sun and Matsuoka 1999) etc. The typical sand models are amended to include the effects of cohesion, as proposed by Lagoia and Nova (1995).The mechanical response of cemented sands is understood to be transitional to the behaviour of a typical particulate assemblage and a quasi-brittle material. However, the effect of length scale in these material systems has not been investigated. This paper presents a series of uniaxial compression experiments conducted on weakly cemented sand specimens of various sizes. The effect of length scale in these weakly cemented sands is investigated through unconfined compression tests."

Jan 1, 2015

By T. Melfi, M. James

Attaining required mechanical properties in welds made using the double submerged arc welding (DSAW) process is difficult, and it is becoming more difficult as the strength level of the base materials continues to increase. Producing weld metal with adequate mechanical properties involves factors that are often overlooked and not taken into consideration. Not least amongst these problems is simply finding information to use in selecting the appropriate flux/wire combination. Most of the available data on flux/wire combinations provided by consumables manufacturers is generated using the multiple pass welding procedures required for classification per specifications such as AWS A5.17 and A5.23. This data really gives no insight into the properties that can be expected in a DSAW application. Also, base plate composition plays a very significant role because of the fact that base plate dilution can be as high as 70% in DSAW welds. This means that if any elements are present in the base metal that are deleterious to mechanical properties, they will also be present in significant quantities in the weld deposit. Some of these elements can decrease toughness and increase hardness (increased hardness is a concern if the pipe is intended for sour service). Some of these problems can be mitigated by proper selection of welding consumables. Selection of proper welding consumables means selecting an electrode that provides the appropriate alloying elements to obtain the desired level of impact toughness while also keeping the hardness within any specified limits. In order to attain the necessary impact toughness, selection of a flux with an appropriate composition (in terms of its basicity and its ability to control the nitrogen content of the weld deposit) is required. As with all welding processes, the mechanical properties of DSAW welds are also highly dependent on the welding procedures. This work clarifies how to select appropriate consumables to meet a given set of requirements, and also how to achieve the optimum mechanical properties from those consumables.

Jan 1, 2005

By A. B. Luz, A. Middea

Kaolin clay is heavily used in the paper industry as a coating and a filler, however to attend the specifications required by the industry it has to be processed. Kaolin is also used as a filler and pigment in various materials, such as paint, plastic, rubber etc. Some crude kaolins as mined in Northern Brazil, contain colored impurities such as iron oxide and rutile/anatase. These minerals normally are stained by iron and as a result vary from yellow to dark brown in color. The kaolin beneficiation process used in that region consists mainly of degritting, fractionation by centrifuge, high gradient magnetic separation, bleaching with sodium dithionite, filtering and drying. In some kaolin clays from that region, titanium oxide mineral occurs in fine fraction, lower than 2 µm, and so making the industrial process more difficult. The conventional method of classification and bleaching with sodium dithionite, markedly improves kaolin brightness, but has little effect on anatase removal. In fact, the fine fractions resulting from centrifugation, in many cases contain more TiO2 minerals than the original whole clay or the coarse fraction. The present work is related to purification of Brasilian kaolin clay using selective flocculation for removing its colored impurities such as rutile and anatase. This study was conducted in bench scale and it consisted of: blunging, screening, conditioning and decantation. Overflow and underflow resulting from settling of the flocculated material were then dried and submitted to TiO2 and brightness analyses. Sodium polyacrylate and sodium silicate were added to kaolin clay suspension as dispersant and ammonium hydroxide was also added to adjust pH. After degritting, the minus 44 µm fraction was conditioned with hydroxamate surfactant and then polymers of different anionic charge were added. The influence of pH and type of polymer on efficiency of TiO2 removal, as well as kaolin mass recovery were studied. The results obtained in the present study are quite promising. It was possible to diminish TiO2 content and increase kaolin brightness (ISO) from 82 to 88%.

Jan 1, 2004

By T. Gonzales, M. Maleki, M. Caçador, B. Climenhaga, H. Ghorbani

The campaign life of furnaces in the copper making industry is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper monitoring and assessment of the existing conditions and safe remaining life of the vessels and their refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a typical fitness-for-service assessment of a rotary vessel shell in order to extend the campaign life of copper making furnaces and enhance safety. The furnace refractory management system involves a comprehensive audit and monitoring program which has been successfully applied to several copper flash smelting furnaces over the past 15 years. The fitness for service assessment provides a methodology to estimate the remaining life of the steel components by evaluating the existing damage and future damage rate based on the historical survey data. The above practices can provide the operator with cost savings by extending the vessel campaign life in lieu of implementing more rigorous refractory lining and shell audits. INTRODUCTION Primary copper smelting is generally divided into two categories of flash smelting and open bath smelting. There are many different types of vessels that can be used to convert the copper concentrate to blister copper including, flash, Mitsubishi process, TSL (ISA/Ausmelt), SKS Bottom Blowing, Anode and Teniente/Noranda furnaces, reactors, and Peirce Smith converters. Each vessel has its own complex and intense environment which requires careful refractory and steel design to withstand the severe thermomechanical and thermochemical attacks within its campaign life. The campaign life of furnaces is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper assessment of the existing conditions and safe remaining life of the vessels and/or refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a fitness-for- service assessment methodology to estimate the remaining campaign life of copper making furnaces resulting in cost savings and enhanced safety of the operating vessels.

Jan 1, 2019

By L. Nutter, J. Clancy

"Barite is used extensively by the oil and gas well-drilling industry as a weighting agent. It is particularly well suited for drilling mud because of its qualities; it is non-abrasive, heavy, virtually inert chemically, easy to handle and inexpensive compared to other available heavy materials. Increased deep well drilling in Western Canada, and especially in the Arctic regions, could dramatically affect the demand for barite through this decade. Known deposits in northeast British Columbia are possible sources of incremental barite supplies, should the situation develop.IntroductionThe purpose of this report is to examine the opportunities for expanding barite production in British Columbia. Of primary interest will be the relationship between the projected future levels of production and consumption of barite in Western Canada and the extent to which increased domestic production could replace the need for imports in filling any expected supply shortages.After a brief overview of the nature and uses of barite and some of the relevant features of the barite supply industry, the discussion will turn to the supply gap in the Canadian market and the possibilities for import substitution.OverviewBarite is an industrial mineral which is used in large quantities by the oil and gas well-drilling industry. It is often an important component of drilling mud, a fluid circulated continuously in the well during the drilling process to lubricate and cool the drilling apparatus and to contain the high oil and gas pressures found at depth. Barite (BaSO4) is particularly well suited as a weighting agent for drilling mud because it is a heavy (specific gravity to 4.5) inert mineral which is inexpensive in relation to other materials having a high specific gravity. In the on-site use of drilling mud, ground barite is combined with numerous other solid ingredients and chemicals in the form of a slurry. Other advantages of barite include cleanliness, ease in handling and its non-abrasive character (hardness of 3-3.5)."

Jan 1, 1982

By M. Falutsu

"The PSI-200 is a rugged, innovative, and easy to install on-stream size analyzer. Its calibration is simple and can be done on-line, during operation. Two measurements are displayed on the panel, which are expressed as percent passing a selected size, or as any statistical diameter. These two measurements are given as two continuous 4-20 mA output signals. Operation alarms are displayed on the screen or are given as digital output signals.The PSI-200 has been used in various applications at Lakefield Research. Particle sizes ranging from 10 µm to 450 µm have been monitored successfully, with an accuracy of 1- 2%. Having the size measured continuously and reliably, optimum conditions have been established for the grinding circuit, resulting in a superior quality in pilot plant testing.INTRODUCTIONThe challenge of any operating plant is to optimize product quality, maximize throughput and minimize operating costs. The importance of particle size measurement at a grinding circuit is well recognized. Monitoring continuously the particle size and keeping the product as uniform as possible is crucial to the whole mill operation regardless of the nature of the operation.Various techniques and instruments have been developed over the years attempting to give reliable on-line size analysis data. The operating difficulties and the reliability of these equipment still present major drawbacks and none of them proved to be widely accepted.PSI-200 is a relatively new on-line analyzer. The operation is simple and of low cost and the maintenance required minimal. It measures particle size and it displays two parameters of the solids size distribution, either weight fraction of passing a certain size or any statistical diameter. Two analog outputs can be sent to a process control system and through a supervisory control loop the correct action can be taken to maintain the desired particle size (perhaps adjust the feed rate to the grinding mill)."

Jan 1, 1993

"The ore currently being milled at Delnite is a high pyrrhotite ore with the gold intimately associated with the pyrrhotite. To get maximum recovery of the gold with the lowest reagent cost, it is necessary to keep the pH as low as possible In the laboratory the best results were obtained with a pH of 10 but in the plant it was found that a pH of 11 was the minimum practical pH. With the n1anual control it was difficult to maintain this figure.The Mines Branch had a conductivity probe (see Fig. 1), developed by Dr. G .G. Eichholz that they wished to try out in plant operation.On June 17, 1963, the probe with all necessary control equipment was installed in the regrind circuit (see Fig. 2) at Delnite Mines. Crushed quick lime is fed at this point but it is also necessary to feed hydrated li1ne at two other points in the cyanide circuit in order to maintain the pH close to 11. 0 throughout the circuit. Only the feeding of the quick lime at the regrind mill was controlled in this test.One thing that concerned me with the operation of the probe was whether the reading on the probe chart would correspond to the pH. A look at the graph accompanying this paper will show that except for very minor variations the graphs of the chart reading and the pH reading are parallel. The upper graph shows that the pH reading and the lime titrations also correspond and that the cyanide titrations appear to have little effect on the pH reading.Table 1 gives the results obtained for the two months before and after the instal1ation of automatic control as well as the two months of control. Unfortunately there was a decided change in ore just after the automatic controls were removed. There was much less pyrrhotitc in the ore than usual thus changing the need for lime and cyanide."

Jan 1, 1964

By J. C. Ingles

"A survey of possible methods for controlling cyanide concentration indicated that the simplest method would involve the use of a potentiometric technique. Such a method was suggested by a paper from the laboratory of Mines Safety Appliances, which described a method for determining hydrogen cyanide in air. In this application, the cyanide was absorbed in caustic and a silver electrode immersed in the caustic solution provided a measure of the cyanide concentration. However, our attempts to use the silver electrode in this simple manner to measure the cyanide concentration of solutions were not very successful. A study of the mechanism by which a silver electrode responds to cyanide concentration made it evident why this simple procedure is not satisfactory.Basically, the silver electrode provides an indication of the free silver ion concentration of a solution, and generally speaking, ignores the other ions' present. It can be used to measure an anion if this anion complexes silver. This technique has been used in complexing studies to determine the activities of such anions as acetate, citrate, oxalate and chloride. To do this, the electrode has to be placed in a solution which initially contains a known concentration of free silver ions. Addition of the complexing anion causes a drop in the free silver ion concentration and hence a change in the potential of the silver electrode. The change in potential can be expressed in terms of the concentration of the complexing anion, and used to indicate its concentration in the solution being analysed. The determination of chloride-ion by a silver-silver chloride electrode is an example of an application of this technique. The solubility of the silver chloride with which the electrode is coated provides the initial free silver-ion concentration. Depression of this free silver-ion concentration by the presence of the excess chloride ion of the sample solution results in a change in the potential of the electrode which is proportional to the chloride-ion concentration."

Jan 1, 1965

By P. A. Riveros

The literature on the arsenic disposal practices of the metallurgical industry and the long term stability of the disposed arsenic compounds were reviewed from a Canadian perspective. The review was complemented with visits to selected operating metallurgical sites to obtain information on their specific arsenic disposal practices and the behaviour of their impounded residues. The arsenic disposal procedure currently favoured by the industry involves the formation of an insoluble ferric arsenate compound which is allowed to sediment at the bottom of tailings or residue ponds. It has been shown recently that this poorly formed crystalline compound is similar to ?arsenical ferrihydrite? which is ferrihydrite containing strongly adsorbed arsenate anions. Despite concerns about its long term stability on thermodynamic grounds, arsenical ferrihydrite appears to be stable for many years in the proper environment which includes a slightly acidic pH and oxidizing conditions. A high Fe/As ratio and the presence of heavy metals appear to increase the stability of arsenical ferrihydrite. High temperature operations, such as those encountered in the autoclave treatment of refractory gold ores, are conducive to the formation of scorodite, FeAsO42H2O, and/or a series of ferric arseno-hydroxy-sulphate compounds depending on the solution composition. Scorodite has several advantages over arsenical ferrihydrite as a disposal compound including a lower iron demand, a higher density and a greater thermodynamic stability. New procedures have been developed to generate scorodite at ambient pressure. These procedures would offer significant reductions in capital cost because of the elimination of the need for autoclaves. Lime precipitation which was widely used in the past is being abandoned as a result of strong evidence showing that calcium arsenate compounds decompose slowly in contact with atmospheric CO2 to form calcium carbonate and soluble arsenic acid. In all cases, the long term stability of the disposed arsenic compounds depends on a number of factors including disposal site characteristics, particle crystallinity and size distribution, the presence of complexing agents and the effect of bacterial activity.

May 1, 2002

By P. J. Poirier, J. A. Meech, H. Raabe

"An Expert System has been implemented to assist operators in applying knowledge about froth conditions in the control of the flotation circuit at Highland Valley Copper. For some time, the personnel at Highland Valley Copper have recognized that froth type is a useful indicator of good operating conditions. However, the operating strategy based on froth type recognition is an ad-hoc skill in which different operators use a variety of terms, features and procedures to identify and solve problems. The first phase of this project developed an on-line consultative system to advise and tutor so that the diffuse expertise could be rationalized and consolidated into a standardized format.The second phase has brought this knowledge into a real-time environment to advise the operators on the floor in identifying froth types and troubleshooting corrective action. This paper describes the steps taken to acquire the knowledge, to design the required system features and to implement the real-time version of this system.INTRODUCTIONThe use of expert systems in the mineral industry has been gaining popularity in recent years. Minnova Inc, Les Mines Selbaie, Wabush Mines, Potash Corporation of Saskatchewan are just a few examples of Canadian mining companies that use expert systems to monitor or control their plants. Applications in the field of flotation include Brenda Mines (Edwards, 1992), Mt Isa Mines Ltd (Lacouture et al, 1991), Outokumpu (Karhu, 1989) and Kidd Creek (Burrows et al., 1989).Expert systems are defined as ""computer systems that apply reasoning methodologies on knowledge in a specific domain in order to render advice or recommendations much like a human expert"" (Turban, 1988). The main areas of application are diagnosis, training, process monitoring and control, and design. There are basically two main types of expert systems: Consultative systems, which are off-line applications in diagnosis and design, and on-line realtime systems, used for supervisory process control and real-time advising."

Jan 1, 1993

By Yugo Mitani, Tatsuya Kato, Chiharu Tokoro, Abdullah Al Mamun

Acid mine drainage (AMD), which is a major source of mining pollution, often contains ferric and/or ferrous ions together with several toxic elements. The ferric and ferrous ions in AMD precipitate in several mineralogical forms after neutralization, and the ferric/ferrous precipitates become the main component of the sludge generated after AMD treatment. The precipitates are also good absorbents for several toxic elements. To avoid generation of voluminous sludges and the re-dissolution of toxic elements from the sludge, it is very important to generate well-draining and efficiently adsorbing sludges by controlling the mineralogical form of the ferric/ferrous precipitates. Green rust, which is ferric and ferrous hydroxide, is a double layer hydroxide which is able to sorb several toxic elements. The green rust transforms to goethite or lepidocrocite by rapid oxidation, whereas it transforms to magnetite at ambient temperature by slow oxidation. The magnetite is also good absorbent especially for toxic cations and it makes a compact sludge due to its magnetic properties. We investigated the magnetite generation process at ambient temperature in detail. The magnetite generation process can be divided into three steps; (i) oxidation of Fe(II), (ii) Fe(II) surface complexation to Fe(III) hydroxide, and (iii) crystallization of magnetite. More magnetite can form when the oxidation rate is slower than the crystallization rate, and optimum conditions for its formation are at pH 9.5 with mild agitation. Ferrihydrite is the most common precipitate and it is able to sorb many different toxic elements. However, it drains badly and its solid/liquid separation properties are poor. We investigated the removal mechanism of several toxic elements by co-precipitation with ferrihydrite. We confirmed that the removal mechanism by co-precipitation partly involved surface precipitation when the initial ratio of toxic elements to ferric ion was high, although the main mechanism was always surface complexation. When surface precipitation occurred, highly efficient toxic element removal with ferrihydrite could be achieved.

Jan 1, 2016

By Lynn C. Fister

"Coal is rapidly becoming a major alternative to oil. According to the World Coal Study Final Report, total world coal trade could approach one billion tons annually by the year 2000. To facilitate the increased production and export market potential of the coal producing countries, advancements must be made to improve the transportation systems. Coal slurry pipeline systems could play a significant role in achieving these market forecasts.There are three major components to a coal slurry system the preparation plant, the pipeline and the dewatering plant. The experience and expertise gained from the Consolidation Coal Company system in Ohio, the Black Mesa system in Arizona and ETSI's Coal Evaluation Plant demonstrate that slurry pipeline technology is proven and available to meet the coal transport challenge.The costs of transporting coal by slurry pipeline can offer significant savings, as about 70 per cent of its costs are fixed. The reverse is true for railroads, where 75 to 80 per cent of the costs vary with inflation. All forms of transport-rail, barge and pipeline-will be required to move the massive volumes of coal. Coal slurry systems can provide a viable transport alternative.IntroductionThe importance of coal as a major alternative to oil is now well known and accepted throughout the world. Increasing oil prices over the last eight years have had a serious effect on national economics, particularly in those countries that are heavily dependent on oil. Coal can replace oil as the principal fuel source which could support world economic growth over the next two decades. This is the main conclusion of the World Coal Study (WOCOL) Final Report, published in May 1980.The product of that report was a result of considerable deliberation by key industry leader s and energy experts. The underlying message of the World Coal Study is that our energy and economic problems can be faced with confidence if coal use doubles by the early 1990s and triples by 2000, and if steam coal trade expand s considerably."

Jan 1, 1982

By P. Venkatasubramanian

"In recent years, computer based ""expert systems"" have been taking on large complex tasks for which no exact algorithmic solutions are feasible; tasks previously reserved for human experts requiring empirical knowledge, judgment, experience, developing a ""best solution "" by the use of plausible reasoning. Mining method selection is an appropriate area for the application of an expert system because extensive and detailed knowledge is required to make a ""best"" interpretaion of frequently ambiguous geological information. The expert system model presented here would enable users to apply expert knowledge to the evaluation of methods for coal deposits mineable by underground methods. IntroductionIn an increasingly complex and specialized world, human expertise spanning scientific, economic, social and political issues plays an increasingly important role in all branches of engineering. This is especially true of mining engineering. The number of scientific and professional disciplines involved in mine planning and evaluation, illustrates the problem. A conservative list includes geology, geophysics, geotechnics, hydrology, mining, environment, and economics.Engineers are almost obliged to be experts in at least one of the above disciplines if they are to handle the volume of information required in the planning process. Although computers have become indispensable tools in many endeavours, there is continued reliance on the human expert's ability to identify and synthesize these diverse factors, to form judgments, evaluate alternatives , and make decisions . This is especially true with regard to problems that are not easily amenable to precise formulations.The precious resource of human expert is also fragile and transient. The departure of a crucial expert from an organization ma y cause serious dislocations. Senior experienced people impart their knowledge of younger colleagues, but the demand for their talent may not leave sufficient time for such educational efforts. In recent years, computer based "" expert systems"" have been taking on large complex tasks for which no exact algorithmic solutions are feasible; tasks previously reserved for human experts, requiring empirical knowledge, judgment , experience, developing a ""best solution"" by the use of plausible reasoning."

Jan 1, 1988

By K. Enns, J. J. Byerley

"While thiocyanate (SCN-) is used in a number of industrial processes (production of polyacrylonitrile filaments, synthesis of agricultural chemicals and certain metallurgical solvent extraction and flotation circuits) it is recognized more as an undesirable by-product associated with ' the metallurgical industry. Thiocyanate is present at low concentrations in some waste streams from the iron and steel industry. Of particular significance is the formation of thiocyanate during cyanidation of gold and silver ores, concentrates, tailing s and residues. The thiocyanate levels present in the resulting effluents may range from a few mg/I to several thousand mg/I.At present, thiocyanate does not appear to be as hazardous in the environment as cyanide (CN-) at the same concentration although its interaction with other species and resulting decomposition of products may be unacceptable. Of course the presence of thiocyanate in the leaching circuit and ultimately in the effluent streams may add considerably to the oxidative requirments of any non-selective treatment process for cyanidation wastes.With respect to the thiocyanate as it relates to the cyanidation process, two aspects are evident. Thiocyanate forms and persists in the cyanidation circuit resulting in a ""fouling"" condition with subsequent loss of leaching activity. In order to reduce or control this problem, it is common practice for some mills to discharge daily as much as 20% of the barren leach liquor. Besides contributing to fouling of the leach liquor the formation of thiocyanate represents an irreversible loss of reagent cyanide. It is noteworthy that in some present or proposed mill practice reagent cyanide loss through thiocyanate formation may reach 50%(1). The purpose of this paper is to discus s the application of controlled electrooxidation of thiocyanate with the view of suggesting a process for regenerating cyanide from waste thiocyanate(2). The paper describes the important theoretical aspects and presents experimental data obtained for thiocyanate electrooxidation using both small and large scale electrochemical reactors. Some economic conclusions are presented."

Jan 1, 1984

By Eric D. Monrad

Supply chain simulation modeling is taking on a more prominent role in mining project planning and decision making. Transportation costs for the supply chain can form a significant component of the overall cost to provide product to the end customer. In recent years, computing power has increased, simulation software has advanced, and simulation specialists have become even better equipped to provide sophisticated analysis and recommendations. This has led to a virtuous cycle of owners expecting and supporting data-driven analytics, which drives further advancement. This paper discusses developments in supply chain planning and two case studies from recent simulation modeling analyses.

May 1, 2013

By A. Poor Zaeif Doost

With columns being installed in rougher section at Miduk Copper Complex, the rougher feed mainly reports to rougher-scavenger cells. To evaluate the efficiency of regrinding circuit, we conducted flotation experiments on samples of the feed and the products of the regrinding circuit. The grade difference of these products at 85% recovery was considered as the efficiency index. Results show that, with weight recovery of the rougher-scavengers the efficiency of the circuit increases. Exclusion of the rougher-scavenger concentrate from the feed to the regrinding circuit, resulted in an increase in the efficiency index from 10.12 to 17.6%.

Jan 1, 2012

By R. Gordon, J. Palich, W. Qian

The EarthProbe DCIP system deploys tightly spaced electrodes connected to a centralized data acquisition system that enables arbitrary selection of current and potential electrodes through relays. Rapid data collection (approximately 1000 readings per hour) and advanced signal processing allow for efficient use of conventional and novel arrays and the removal of natural and cultural noise. What is unique about the system is its electrode and borehole cable design, which allows seamless integration of borehole and surface measurements. EarthProbe operates in four configurations - surface, borehole, borehole-to-borehole, and surface-to-borehole (a variant of the borehole-to-borehole configuration).

Jan 1, 2011

By Robert D. Irvine

"Enhanced concern for protection of the environment and attendant actions by environ-mental regulatory authorities in support of this concern are influencing, to varying degrees, the demand and supply of a range of industrial minerals in a number of jurisdictions. These influences take a variety of forms.In this paper, the author seeks to delineate certain broad trends which are occurring relative to industrial minerals and the environment and then, through a series of examples, to outline opportunities, developments, and impacts respecting a number of industrial minerals produced and consumed in Canada and the United States."

Jan 1, 1996

By David W. Smith

"This paper is devoted mainly to a discussion of the hydrocarbon potential of the offshore, with a few brief remarks concerning the inorganic mineral potential.OFFSHORE OIL AND GAS POTENTIALIN ORDER TO HAVE HYDROCARBON ACCUMULATIONS, we must satisfy three basic requirements. First, we re-quire a sufficient thickness of sedimentary rocks which contain some porous and permeable formations to act as reservoirs. Second, we require some type of trapping mechanism, such as faulting, folding or stratigraphie trapping. Finally, we require that large quantities of hydrocarbons have been generated within the sedimentary rocks and have migrated to the traps."

Jan 1, 1969