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By P. C. Benedict

"The Island Mountain mine is at the southeast end of Island mountain; across Jack of Clubs lake from the Cariboo Gold Quartz mine.; The orebodies consist of quartz veins and pyritic replacement deposits in limestone. To December 31; 1944; there has been mined 296; 273 tons of quartz-vein ore averaging about 0.34 oz. gold a ton; and 101; 002 tons of sulphide ore averaging about 0.83 oz. gold a ton; a total of 397; 275 tons averaging 0.46 oz. From this; 175; 985 fine oz. of gold and about 26; 450 fine oz. of silver were recovered; having a value of $6; 510; 521.More than 95 per cent of the production has come from a band 500 feet wide along the contact of the Rainbow and overlying Baker members and extending about 100 feet into the latter. Evidence that the Rainbow belongs stratigraphically above the Baker is presented later in this paper. Both members are most variable lithologically, and individual beds and whole series of beds pinch out in short distances. In part, at least, this is due to squeezing out incidentally to intense folding. No section can be claimed with assurance to be really representative. However, both memb.ers are composed predominantly of quartzitic rocks. Both contain argillaceous quartzite, argillite, limy quartzite, limy argillite, limestone (marble), and minor amounts of highly ankeritized rocks believed to be igneous sills possibly originally approaching diorite in composition."

Jan 1, 1954

By C. Horstmann, D. Andreo, G. Barthold

"The concept of large single line grinding circuits provides a valid answer in project feasibility studies by reducing capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational aspects, in terms of higher and greater process stability, and reduced operational costs mainly due to the associated lower maintenance expenditures. However, concerns exist in the minerals industry on whether large single line grinding could reduce the overall concentrator plant availability. The mechanical design and integrity, the mill and gearless mill drive integration, as well as assets management aspects of this type of equipment are the key to guarantee successful availability records. Together with an overview of the added value provided by large single line grinding circuits, this paper focuses on risk mitigation strategies during mill and gearless mill drive integration, as well as on the design of the equipment itself, for the key aspects which could put at risk the operations availability.INTRODUCTIONDespite a large long term demand for commodities, the mining industry has never faced complex challenges as it is doing today. Decreasing high-quality and accessible deposits, declining ore grades in existing mines, shortages of electrical energy (e.g. in Chile) and an aging workforce are the most significant among the megatrends affecting our industry. In addition to this, flat underlying commodity prices and high price volatility are currently posing strong requirements to miners when entering into the process of approving investments.Nowadays to get projects financially approved (optimizations, expansions, new plants), capital expenditure has to be reduced, as observed up to 30% compared to the last decade, and at the same time the plant design has to be such to demonstrate that operating costs will also be significantly lower than in the past.When it comes to the concentrator plant, the concept of large single line grinding circuits provides a valid answer in project feasibility studies by significantly reducing the capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational costs, in terms of higher and greater process stability and reduced maintenance expenditures."

Jan 1, 2016

By V. L. Mitsopoulos

This paper provides a summary of tailings disposal techniques and the improvements that have been made through the introduction of thickened tailings disposal. The general properties and characteristics of thickened tailings are described, as is a design process for selecting appropriate technologies for thickening, pumping, transporting and storing tailings. The factors affecting the selection of an appropriate disposal site and operational considerations for the effective utilisation of tailings storage areas are also documented.

Jan 1, 2006

By C. Joulian, A. G. Guézennec, A. Chmielarz, Y. Ménard, M. Hanke, P. d’Hugues

"The copper concentrate used in this study is produced by flotation of a black shale organic rich ore. This resource is a carbonate-rich, polymineral concentrate. In the last 5-6 years, ore characteristics changed and the concentrate grades degraded. This study evaluated bioleaching of the concentrate in stirred tank reactors as an alternative to the pyrometallurgical technology that is currently applied, and which may no longer be feasible in future given the concentrate chemistry.The first part of the study focused on testing non-traditional operating conditions during continuous bioleaching experiments: high solids concentration (> 20% solids), reduced agitation and aeration rates. For the same residence time, bioleaching performance at high solids loading (25%) was the same as that reached during previous bioleaching experiments at 15% solids. No mixing or microbial issues were encountered. The bacterial consortium used in the experiments demonstrated a high copper tolerance.The second part of the study was devoted to technology development for metal recovery from copper bearing solutions obtained during bioleaching experiments. Due to the high copper concentration of the leachate, solvent extraction prior to electrowinning was not necessary. After iron removal, high quality copper cathodes (morphology and composition) were obtained from the PLS by electrowinning."

Jan 1, 2014

By Lifeng Yang, Xiang Zhang, Liang Yuan, Yonghui Wang, Bing Hou, Mian Chen, Rixing Zhang

Large-scale hydraulic fracturing technique has been widely applied to the development of shale gas reservoirs, where the interaction between natural fractures and critical fracture zones has substantial impact on the propagation of hydraulic fractures. Therefore, it is of significant importance to understand and experimentally verify such mechanism. To reach this end, tri-axial fracturing tests were implemented on 400mm×400mm×400mm block samples collected from Longmaxi shale outcrops. The interplay between hydraulic and natural fractures was investigated during the tests, factoring in the role of pump rate in affecting the created fracture network. Based on the experimental results, the critical fracture zone, defined as the weak formation zone nearby the wellbore created by staged pressure implementation that is observed rapid fracture propagation upon next stage of pressure increase, was thoroughly investigated. The analysis illustrates that given the high brittleness of the shale formation, abundant critical fracture zones are generated around natural fractures with pressure building up at a relatively low pump rate. As the pump rate increases, hydraulic fractures initiate and come into play with critical fracture zones, implying emergence of a large number of micro-cracks. A changing pump rate modifies the way of interaction between hydraulic and natural fractures and the subsequent formation of fracture network. Long term fracturing fluid injection with relatively low pump rate below the activation of critical zones is suggested. Also proposed is appropriate timing when applying a specific pump rate that will contribute to the improvement of hydraulic fracture propagation.

Jan 1, 2015

By J. R. Welsh, D. J. Palmer, O. M. G. Newman

"The use of calcine for selective zinc precipitation requires specialist knowledge to achieve satisfactory flowsheet design. Calcine from the bed of a fluid roaster is preferred, and factors such as the size distribution of ground calcine, the stoichiometric ratio of the calcine precipitant to the initial dissolved zinc concentration and the moisture content of the resultant filter cake are parameters which require critical attention. Extensive testing in a fully-integrated electrolytic zinc plant pilot plant has demonstrated that properly designed selective zinc precipitation plants using calcine as the precipitant are reliable operating units.The advantages of using calcine instead of limestone for selective zinc precipitation include a decreased cost of reagents, as well as avoiding the formation of by-product gypsum.Process simulation modelling has demonstrated that the use of calcine in this context has widespread application in the design of zinc plants with superior impurity and water balance control characteristics. A particularly powerful approach involves closed circuit washing. In this mode, filtrate from the selective zinc precipitation step is used to wash a zinc plant residue such as jarosite, and the resulting filtrate is returned to the selective zinc precipitation section. IntroductionThe Selective Zinc Precipitation (SZP) Process, developed and patented by the Electrolytic Zinc Company of Australasia Limited (EZ) may be used to achieve simultaneously, water balance and impurity control in an electrolytic zinc plantO,2). Impurities which may be controlled by the SZP process include chlorine, magnesium, manganese, potassium and sodium.In the SZP process, basic zinc sulphate is precipitated from a zinc sulphate solution by either limestone, lime or a compound containing zinc oxide, usually calcined zinc sulphide concentrate (calcine) or alternatively zinc oxide fume .The solids containing basic zinc sulphate are separated, typically, by filtration and returned to the zinc plant circuit as a neutralizing agent. The zinc depleted solution can either be discarded, or used to wash residues, thereby achieving water balance and impurity control (Fig. I)."

Jan 1, 1988

By David R. Lentz

Abstract -At True Hill in southwestern New Brunswick, low-grade porphyry-style Bi-Sn-Mo greisen mineralization is associated with the cupola of an epizonal granite porphyry (granite) that also exhibits three episodes of brecciation. The first episode of brecciation is an in situ, 8 m to 10 m wide transitional zone of net-veined to coarse-grained "blocky" endogranitic mesobreccia that is chloritized and greisenized and hosts weak disseminated mineralization. ln a zone doser to the host rock­ granite contact, angular fine- to coarse-grained endogranitic mesobreccia with greisenized matrix is superimposed on the earlier transitional breccia. The latest episode is fault-controlled and consists of quartz- and chalcedony-hosted subangular to rounded fine-grained "pebble" mesobreccias that crosscut and brecciate the other breccia types, as well as the adjacent altered metasedimentary country rocks. The first two episodes of brecciation are magrnatic-hydrothermal in origin related to hydrofracturing of the granite carapace and are accompanied by greisenization and mineralization, whereas the post-mineralization, silica-hosted, "pebble" mesobreccias related to hydromagrnatic, low­ temperature fluid circulation and/or boiling along faults near the contact. These magmatic­ hydrothermal and hydromagmatic mesobreccias are similar to those associated with W-Mo-Bi porphyry-greisen mineralization at the Mount Pleasant deposit.

Jan 1, 1994

By Constantin D. Pitis

?Demand-side measure" means a rate, measure, action or program undertaken to conserve energy or promote energy efficiency?? (BCUC, 1996) In actual economical environment, business sustainability requires high-efficiency technological processes. That is why the efficiency concept has to be present at all levels of industrial activities. Nowadays, some purchasing decisions are still driven predominately by the purchase price, in spite of the evidence that such price represents up to 5 % to 7 % of the total costs of ownership with full consequences of energy efficiency and the impact on total ownership costs. The paper presents essentials of converter types and basics of the Global Efficiency (GEff) Concept that has been promoted over the last few years in South African industries (Pitis et al., 2006/7). GEff concept is proven as a useful tool used on price-efficiency decisions. Theoretical and technical aspects of this concept were substantiated with case studies. First part presented in this paper will describe how GEff concept was used on price ? efficiency decisions when single input or direct converters and systems (considered as low value equipments) have been replaced. Besides the impact of energy savings and new innovative developments, the paper suggests general other benefits of: ? Technical and economical performance improvements and competitiveness of mining corporations to international standards; ? Defusing incipient energy crisis in the sector; ? Improving environmental conditions; ? Creating new job opportunities in mining sector. Proposed concept in this paper could be further developed as models of improving companies? corporate energy policies.

May 1, 2010

By J. W. Craig

THERE are, broadly speaking, three classes of refractories: acid, basic, and neutral. Fireclay, diaspore, silica, and the sillimanite group of minerals are included in the acid class, which for the most part are not very resistant to basic slags. The neutra! class includes chrome, graphite, and silicon carbide, while most important in the basic class are magnesite and dolomite. Although chrome is a neutral refractory, it has no sharp distinction from magnesitic refractoriness. The two are mineralogically (1) and chemically related, and there is available on the market a complete range of brick from straight chrome to straight magnesite. In many indus trial applications, one. type may be replaced by another. The present paper is confined entirely to such refractories. The following types of basic and neutra! brick, each sold under sorne special trade name, are available for use in Canada: (1) Burned chrome from crude ores (2) Burned chrome from treated ores (3) Chemically bonded (unburned) chrome-magnesite ( 4) Burned chrome-magnesite (5) Chemically bonded ( unburned) magnesite-chrome (6) Chemically bonded (unburned) high-iron magnesite (7) Burned high-iron magnesite (Regular) (8) Burned low-iron magnesite (9) Burned olivine-magnesite (10) Burned magnesitic dolomite-chrome (Magnecon) (11) Chemically bonded magnesitic dolomite-chrome (Magmecom) (12) Dolomitic brick

Jan 1, 1936

By The Staff

"IntroductionThe published information concerning treatment of uranium ores has been very limited as far as Canadian ores are concerned. Such information has dealt mainly with refining processes for concentrates or rich ores, designed to recover radium rather than uranium; these methods could not be economically applied to low-grade ores.The purpose of this paper is to describe treatment possibilities for some of the .ores that have been treated at the Mines Branch, and .to show how the character of these ores influences methods and results.What is a Uranium Ore?Prospecting for uranium has been extremely active during the past two years and a great many occurrences of radioactive minerals have been recorded. Such prospecting has been based to a large extent on the use of the Geiger counter in the fie1d. This equipment is an invaluable aid when the results are properly interpreted.Most definitely, indications of high radioactivity do not always prove the presence of a valuable orebody. First we have to determine:(1) Is the radioactivity due to uranium or to thorium. There is no immediate market for thorium.(2) Can the uranium in the ore be economically recovered.Chemical analysis is the most exact method of determining uranium content, but a fair estimate of the uranium, and also of the thorium, content can be made from the difference in gamma and beta activity. The Mines Branch guards against misinterpretation by determining both beta and gamma activities and, if more than a minor amount of thorium is indicated, then a Chemical analysis is made."

Jan 1, 1950

By Roland B. Hoag, Roger G. Webber

Sulphate concentration in groundwater is a good measure of the extent of oxidation of sulphides, provided that sulphide minerals are the primary source of the sulphate. A study was conducted near the Eustis Mine in Quebec to determine where and how the sulphate in groundwaters originated. Atmospheric precipitation is the only source of sulphate other than oxidation of sulphides, and in this study area it is equal to 0.01,. millimole per litre. The oxidation of sulphides can be divided into subsurface oxidation (mainly inorganic processes) and surface oxidation (including both organic and inorganic processes) . The maximum sulphate concentration due to subsurface oxidation of sulphides depends on the solubility of 0 2 in water and is 0.25 millimole per litre. Surface oxidation is, therefore, responsible for any amount greater than atmospheric plus subsurface contributions (0.29 millimole per litre). Surface inorganic oxidation occurs in waters with a pH greater than 15 and is controlled by the kinetics of the oxidation processes. Organic (bacterial) surface oxidation is dominant only in acid (pH< 1.5) waters. The bacterial action accelerates the oxidation of sulphides, and large quanttties of sulphate may be introduced into solution.

Jan 1, 1976

By Thom Mambe, Angelo Fernando

The objective of this work was to identify key parameters related to the reduction of the sulphur content in ammonium diuranate (ADU), and the identification of solid products being formed under various operating conditions. A laboratory-scale, continuous ADU precipitation circuit was assembled using a glass reactor vessel immersed in a temperature-controlled water bath. A pre-prepared uranium feed solution was fed continuously using a peristaltic pump. Anhydrous ammonia mixed with compressed air was metered and pumped using a double-headed peristaltic pump. An over-head mixer was used to keep the solids in suspension. The precipitated ADU slurry was removed from the reactor at the same flow rate as the feed solution. The slurry was sampled to generate ADU solids for chemical and physical analysis after four hours of continuous operation to ensure steady-state conditions. The following variables were studied to determine their influence on the sulphur content in the resulting ADU. (a) sulphate:uranium molar ratio in the reactor (1:1, 1:5, 1:10 and 1:20) (b) precipitation pH ( pH 6, 6.5, 6.9, 7.5 and 9) and (c) precipitation temperature (40C and 60C) A total of 18 tests covering the above parameters were conducted, and the results indicated that the sulphur content in the resulting solids was highly dependent on the reaction pH. Out of the pH levels tested, tests completed at pH 6.9 and 7.5 generated solids containing the lowest sulphur contents, between 0.5 to 1.5% S uranium basis (UB). The sulphur content in solids was found to vary linearly with the sulphate:uranium ratio in the feed solution, showing a statistically valid correlation. The impact of temperature was minor between 40°C and 60°C, with a slight advantage at higher temperatures. Tests at a sulphate:uranium ratio of 1:1 produced solids with the lowest sulphur contents. The influence of pH or temperature on sulphur content in solids was almost non-existent at this sulphate:uranium ratio. Precipitation pH is the major factor influencing ADU sulphur content, followed by the uranium to sulphate ratio.

Jan 1, 2020

By S. Steinlechner, S. Wegscheider

"In the past, the metallurgical industry was most of the time dedicated on their main commodity, recovering base metals like zinc, copper or lead but leaving other valuable side elements in the generated residues. As a result, these accompanying minor elements, like gold, silver, indium or also PGMs can be found in the dumps of the corresponding industry. Because of political unrest, strikes, economic reasons or decreasing primary resources leading to a high supply risk, also those mentioned minor elements moved into the focus of the recycling industry. Therefore, beside the base metals, first of all the recovery of those minor metals would be of high interest contributing to the economic viability of recycling processes, although they occur in much smaller quantities in materials. In this context, residues from zinc industry, like leaching residues or precipitation residues show high potential to carry silver as well as indium next to lead and zinc. Therefore, the paper summarizes carried out thermochemical calculations investigating a possible recovery of silver as well as indium by volatilization and the influence of zinc and lead on this process. Based on these theoretical investigations with HSC, trials in lab scale were done verifying the obtained results.INTRODUCTIONHuge amounts of iron precipitate, mainly jarosite get landfilled every year although there is a high content of valuable metals in this residue beside iron. Nevertheless, jarosite has to be dumped due to the presence of contaminating heavy metals. The accumulation of these residues takes up massive land on the one hand but also causes a series of environmental problems in ecosystems on the other. Moreover, some toxic ingredients such as arsenic and cadmium can be dissolved in rain water and are therefore harmful to the health of the aquatic systems. (Erdem & Özverdi, 2011; ÖzverdI & Erdem, 2010) Approximately 0.5 t of dry jarosite accumulate in the production of 1 t of zinc by the hydrometallurgical zinc-winning route (Svens, 2010). Jarosite is a precipitation residue formed during the iron removal. In general, the iron already exists in the zinc ore which is why zinc ferrite builds up during the roasting step of the zinc ore. Zinc ferrite is only soluble in strongly acidic solutions and during the hot acid leaching step it gets dissolved while zinc and iron enter the solution. It is necessary to get rid of the iron because otherwise it would deposit on the cathode first due to its precious character which would be harmful in the zinc-winning electrolysis. Nevertheless successful investigations were done by adding chlorine to the jarosite to recover silver. These findings leads to another residue which occurs in huge amounts – electric arc furnace dust (abbreviated with EAFD) from the iron and steel industry. In 2013 the annual electric steel production reached about 451 million tons. Around 15-20 kg of EAFD is produced per ton of steel in an electric arc furnace (EAF), creating approximately up to 9 million tons of dust per year. (Grabda, Oleszek, Shibata, & Nakamura, 2014; World Steel Association) Next to elements like zinc, lead and iron, chlorine and fluorine are present in this dust. While galvanized steel plates in the scrap act as a source for zinc, casting powders, flame retardants and synthetic coatings are responsible for the chlorine and fluorine contents in the dust."

Jan 1, 2016

By D. Chakravarty, D. Dutta, B. Samanta, S. Patteti

"This paper presents the mixed spectral behaviour of iron ores from deposits in Gua, India. Spectral signatures of powder samples and their two-component mixtures were generated by spectro - radiometry. Spectra were divided into continuum and absorption components. A modified Gaussian model was used to extract subtle features from the absorption components of the spectra. A linear unmixing model (LUM) applied to estimate minerals from the spectra of mixed powder samples indicated that this model achieved an R2 value of 0.88. The LUM was then applied to estimate the abundance of ores from a hyperspectral satellite image of the deposit area.RÉSUMÉ Le présent article montre le comportement spectral mixte de minerais de fer de gisements à Gua, en Inde. Les signatures spectrales d’échantillons de poudres et leurs mélanges à deux composantes ont été générés par spectroradiométrie. Les spectres ont été divisés en composantes de continuum et d’absorption. Un modèle gaussien modifié a été utilisé pour extraire des caractéristiques subtiles des composantes d’absorption des spectres. Un modèle de démélange linéaire, appliqué pour estimer les minéraux dans le spectre des échantillons de poudres mixtes, indique que ce modèle a atteint une valeur R2 de 0,88. Le modèle de démélange linéaire a ensuite été appliqué pour estimer la quantité de minerai à partir d’une image satellite hyperspectrale du secteur du gisement."

Jan 1, 2015

By Paul Guliov

Preliminary investigations of stone resources were conducted in the La Range, Johnson Lake-Pelican Narrows-Deschambault Lake and Creighton-Amisk Lake regions of Saskatchewan. The work identified a rich variety of accessible, attractive and technically promising stone resources. Ordovician dolomites in various combinations of red, buff, yellow, grey and purple are very dense and take a very good polish. These are classified as marbles in the industry and some rival the famous marbles of Verona, Italy. A wide variety of attractive granites have been identified. Among these is a jade green stone (charnockite) and ornamental banded granites (gneisses). A dark greenish to black stone (amphibolite) with white and red veining resembles the well-known Verde Antique variety of Vermont and Italy and surpasses it aesthetically and in engineering properties. Some of these stones have been displayed at Canadian and United States expositions where they received an enthusiastic response from the international stone industry. More detailed evaluation and test quarrying of promising deposits are required. Such work could be rewarding to the industry as some stone varieties in the province have the potential for gaining international markets.

Jan 1, 2001

By J. T. Kalala

The High Pressure Grinding Roll (HPGR) is gaining acceptance in the mineral processing industry and has become a competitive technology in reducing the specific energy consumption in Mineral processing plants. The amount of samples required for HPGR amenability testwork and HPGR wear tests is usually high and often cannot be available at early stage of projects were only a few drill cores are available. Although HPGR was initiated from small scale piston die compression tests, the development of small scale piston die test to predict the performance of HPGR has been slow. The objectives of this paper was to present the designs, operating procedure of piston-die press and operating conditions which have resulted in similar particle size distribution obtained from a piston die test and HPGR Labwal unit starting from the same feed size distribution. Testwork were conducted using a 2 MN piston-die press and a Labwal HPGR unit on major South African ore types, viz, gold, platinum and iron ores. The results obtained show that piston-die test can generate data to predict energy consumption, product size distribution, and even to evaluate the edge effect.

Jan 1, 2012

By A. Luckita, A. Samtani, R. Barus, J. R. Donald, J. Syarifuddin

In conventional Rotary Kiln-Electric Furnace (RK-EF) laterite nickel processing, management of dust continues to be problematic. A more efficient processing of dust represents an opportunity for energy efficiency, increased production, and productivity. PT International Nickel Indonesia (PTI), together with Vale Base Metals Technology Development (VBMTD), has successfully developed and implemented a novel flowsheet enhancement that capitalizes on these opportunities. In the novel flowsheet, the dust recycle stream is moved forward in the RK-EF laterite nickel smelting process. The dust is injected into the kiln&apos;s main burner, as opposed to being recycled to the dryers. A similar treatment of dust is commonly practiced in the cement industry; however, application to nickel smelters has not been fully developed to date. This paper describes this dust insufflation technology, the process through which it was developed for laterite nickel processing, and summarizes the lessons learned. A key conclusion is that successful new technology development requires a multi-disciplinary team involving members from research and development, study management, engineering consulting firms, project implementation management, process technology and operations.

Jan 1, 2011

By M. Lytle

"The Corbin area of southeastern British Columbia has been a coal mining area since 1908. Byron Creek Collieries Ltd. Has operated its Coal Mountain Mine in this area from 1974 until the present. In February 1981, this company was purchased by Esso Resources Canada Ltd.Coal Mountain is structurally complex and standard computer algorithms are not applicable to model the overturned synclinal structures and faulted bedding surfaces. This paper discusses two approaches used by Esso Resources staff to model the geology of Coal Mountain.The first approach projects digitized cross-section data along trend to develop a large data base which correctly approximates the shape of the structure. The spatial orientation of the structure is corrected by merging the generated data set with drill-hole data. The second approach uses digitized cross-section and bench-plan geology to generate a block model of the coal reserve.HistoryThe Coal Mountain Mine, also known as the Corbin Mine of Byron Creek Collieries Ltd. is located 24 kilometres south of Highway 3 in southeastern B.C.In 1905, two American businessmen recognized the coal potential of the area during a horseback tour. The two businessmen, D.C. Corbin and E.J. Roberts, formed the Corbin Coal and Coke Co. to mine and market coal from their newly acquired 6075 hectares of coal licenses. By 1908, the town of Corbin was under construction, a 22.4-km rail spur was constructed from the mine to the main CPR line and the first underground mine began to produce coal. An open-pit operation was also developed at the 1828-metre elevation using a steam shovel loading into rail cars. The company operated continuously until 1935, when a lengthy strike forced suspension of operations.In 1943, the Consolidated Mining and Smelting Company Ltd. (now known as Cominco Ltd.) operated two surface mines to produce coal for its smelters at Kimberley and Trail, B.C. This operation ceased in 1948."

Jan 1, 1982

By J. Tuzo Wilson

"AT ANY TIME, it is a pleasure to me to be invited to address The Canadian Institute of Mining and Metallurgy because it represents an industry and men with whom I have been happily, if peripherally, associated continuously for forty years. This year, it is a particular pleasure because I believe that an important subject has arisen which I propose to discuss.This is a major discovery in the earth sciences, first fully revealed this winter, but already widely accepted. The basis of this revolution, for it is no less, is that measurements of three different features of the earth all change in exactly the same ratios. These ratios are the same in all parts of the world. The results from one set are thus being used to make precise numerical predictions about all the sets in all parts of the world. No such accurate correlations and predictions have ever been found before in geology or areal geophysics. The whole subject of earth science has thereby been radically altered.The first of these measurements is that of the direction of magnetic polarity in lava flows. When piles of young lavas are examined with the aid of a pocket compass, it is noted that some flows are magnetized in the direction of the earth's field and some in the reverse direction (Figure 1). By accurately dating enough flows, a time scale of the dates of reversals has been established. During the past four million years, nine reversals have occurred synchronously all over the world (Cox, Darymple and Doell, 1967, McDougall and Chamalaun, 1966) (Figure 2). It appears that the scale can be extended back to Precambrian times (McMahon and Strangway, 1967). This time scale is the first of the 'three identical ratios."

Jan 1, 1968

By K. Blower

"Since there was no representative from Wesfrob Mines Limited, the information on their infra-red concentrate drying operation, which had been prepared by Mr. K. Blower, was presented by Mr, Dorland. Mr. Blower, in submitting the information, emphasized that their objectives in this operation were (a) to guarantee less than 90%, of flow-moisture in their copper concentrates and thus satisfy marine shipping regulation• and (b) to minimize capital costs, The infra-red dryers have satisfied these objectives.To control final moisture in the copper concentrate, current practice is to preheat the filter cake with steam in the disc filter hood and then conveyor-0r7 the concentrate with infra-red calrod heaters. The application of steam aids the system as follows:1) Improves vacuum pump efficiency.2) Lowers viscosity of filtrate (increased temperature},3) Preheats the cake prior to radiant heating. (150°F)The hot cake discharging from the filter ranges from 10.6 to 10.9% moisture. After radiant heating the moisture level is reduced to 8.5% - 9.7% depending on production rate. Further moisture loss occurs during conveying and transferring to the stockpile for a final shipment moisture ranging from 8.1% to 9.5%. Production rate is frail J to 5 dry short tons per hour.1) #23 Conveyor 18"" flat belt covered from filter discharge to transfer point with 7 heaters end-to-end. Drive - Reeves Vari-Speed, 31:4 ratio, type 332-10-18, class ""D"", driving through a 24:1 ratio Dodge reducer. Speed of Conveyor - 3,9 feet per minute to 19.6 feet per minute. (Speed has been established and is not changed as a rule from the present level of a1:out 15.)2) #23 Conveyor 24"" wide, 20° troughed belt covered with 21 heaters, end-to-end from loading point, Speed - Constant at 54,2 feet per minute."

Jan 1, 1972