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By Mohamed Hamoud

Relative permeability curves represent an important element of special core analyses, but challenges remain in obtaining valid results and the extrapolation and use of existing permeability results is problematic. This situation is compounded in cases where core properties are altered from changes in effective stress. During the production of oil and gas reservoirs, the effective stress changes as a result of changes in pore pressure or temperature. Therefore, changes in rock properties such as porosity and permeability will occur and will consequently influence reservoir performance calculations. An experimental program was carried out to understand the behavior of dense, reconstituted sand samples at low effective stress states. Drained triaxial compression tests were set up to study the effect of stress alteration on relative permeability data through porous media. Initially, a saturation stage was performed followed by isotropic loading to bring the core sample to reservoir fluid and stress conditions. Then, while axial (deviatoric stress) loading was applied to the sample, a series of absolute and relative permeability tests was performed under steady state flow at different levels of strain during pre and post peak shearing stress. The stress-strain behavior results from the study revealed that the absolute permeability decreased during isotropic loading (compaction) and increased during shearing (dilation). However, the shape of relative permeability curve changed from contraction to dilation and showed higher initial kro and the lower initial kro respectively. The goal of this project was to understand the behavior of both absolute and relative permeability at different stresses. It is expected that geomechanical processes will be adopted for special core analyses to support the current integration of geomechanics into reservoir engineering. This will be required if, during SAGD, conventional and/or unconventional reservoir simulation, reservoir engineers implement a proper set of relative permeability data at each in situ state of stress, instead of constant curves throughout the field?s life.

Jun 1, 2012

By W. S. (Steve) Vaughan

The Origins of Joint Ventures in Canada?s Mining Industry ? Among the most important financing structures used in our mineral industry today ? Virtually unheard of in the Canadian industry prior to the 1970s ? Borrowed from the U.S. oil and gas sector where it came into prominence in the late 1930s ? The Securities Acts of 1933 and 1934 in effect killed the sale of (equity) shares for financing oil and gas wells and start up mining companies

May 1, 2013

By W. A. Kracht

The McGill Bubble Size Analyzer, with the original image-capturing device (digital video camera), has a proven record for measuring bubble size distributions that are relatively narrow, such as in mechanical cells with frother. However, some problems arise when dealing with bubble size distributions characterized by a bi-modal shape and wide range of sizes such as found in some flotation columns. To measure wide bubble size distributions it is necessary to increase both the resolution to image the small bubbles and the viewing area to include the large bubbles. This can be done using a digital still camera: digital still cameras can have higher resolution than the digital video cameras currently used and with the proper lens the viewing area may be increased without resolution loss. The digital still camera approach was used to measure bubble size distributions in flotation columns at different operations in Chile. A comparison with typical bubble size distributions generated with mechanical cells is presented.

Jan 1, 2007

By K. M. Wild, C. D. Martin, F. Amann

Peak laboratory strength data obtained from low permeability clay shales/rocks often display a bilinear or non-linear failure envelope. In many of these tests pore pressures are not measured because of issues associated with back-saturation prior to confined compressive loading. In such tests the effective state of stress at failure remains unknown and provides room for speculation. The non-linear shape of the failure envelope may have several reasons including the influence of capillary forces or the tendency of a saturated clay shale to dilate as the confining stress is changed. The former stems from sample preservation, preparation or core unloading effects and represents a partly saturated state (i.e., not representative for the in-situ state); the latter represents the response of a saturated material. This contribution discusses these issues based on a data set obtained from Opalinus Clay specimens, and concludes that without a careful back-saturation processes knowledge of the underpinning reasons for the non-linear failure envelope cannot be obtained.

Jan 1, 2015

By L. Jiang

The evolution of twinning in an AM30 Mg alloy was examined by uniaxial tension and compression testing at temperatures from ambient to 250°C and a strain rate of 0.1/s. The samples were cut along the extrusion direction from extruded AM30 Mg alloy tubes. Specimens deformed to various strain levels were examined by optical microscopy and electron backscattered diffraction (EBSD) techniques. The results indicate that the initial extrusion texture plays an important role in the formation of different types of twins and that the twinning behavior also depends on the strain path. Contraction and double twinning are the dominant twinning mechanisms in uniaxial tension, while extension twinning prevails in uniaxial compression. The different twinning behaviors are shown to be responsible for the sharply contrasting strain hardening characteristics of the experimental flow curves.

Jan 1, 2006

By C. C. Li

Traditionally, strong and stiff devices, such as fully encapsulated rebar bolts and concrete lining and arches, are preferred for underground rock support. The attention is paid to the strength of the devices in such support designs. It has been observed in engineering practice that support systems composed of stiff devices are often subjected to premature failure in high stress rock conditions. In the past decade, yield support devices have been employed to improve the performance of rock support systems. A rock support system usually consists of both internal and external devices that are installed within the rock mass and on the free surface of the rock, respectively. Great efforts have been made to make support devices yieldable in the past years, but the efforts are focused on different aspects in the tunneling and mining branches. In the tunneling branch, the focus has been put on the development of external yield devices, such as Lining Stress Controller (LSC), Honeycomb element and compressible concrete, which are embedded in shotcrete liners, while in the mining industry the efforts has been on the development of yield rockbolts, such as the cone bolt and the D-Bolt. The internal and external support devices are not compatible in their deformation capacities in the current rock support systems even though yield devices have been employed. All the devices in a support system should be deformable and compatible in deformation capacity. With such a support system, premature failure of individual support devices could be avoided and the service life of the support system is prolonged. It is a trend at present to take into account the energy absorption capacity, instead of simply the strength, of support devices in rock support design.

Jan 1, 2015

By Guichao Wang, Geoffrey M. Evans, Graeme J. Jameson

"In this paper we present a new method for studying the detachment of particles from bubbles in a rotating turbulent eddy. The eddy is formed in a wall cavity in a two-dimensional water tunnel with transparent walls. When water flows through the tunnel, a vortical flow field develops in the cavity. The properties of the eddy can be modulated by changing the free-stream velocity of the water in the tunnel. Bubbles are pre-loaded with one or more particles in a fluidized bed flotation device located beneath the vortex cavity. Loaded bubbles are released one at a time into the cavity, and the motion of the bubbleparticle aggregate is studied using a high-speed video camera. The diameters of the particles and the bubbles, and the number of particles initially attached to the bubble, can be varied. The trajectories taken by the bubbles are quite complicated. In some cases, the bubble moves to the centre of the eddy, and particles rotate around its axis. If the rotational speed is sufficient, particles may detach due to centrifugal force. However, other modes were observed, including inertial detachment due to rapid changes in direction of the surface of the bubble, because of changes in trajectory of the bubble as a whole, or because of pulsations and oscillations of the bubble surface. Clusters of bubbles held together by particles were seen to form and reform. In the traditional explanation for the detachment of particles in flotation cells, it is assumed that particles detach from bubbles rotating in an eddy due to centrifugal force (Schulze, 1977). Although the conditions assumed in Schulze's theory may exist, it is only one of a range of phenomena that can lead to the detachment of particles from bubbles in a turbulent vortex.INTRODUCTIONThe recovery of particles by flotation methods is dependent on the particle size. The recovery in the existing flotation machines reaches a peak for particle size, typically in the range of 20 to 100 µm. This size range varies as a function of the particle’s properties (type and composites). For coarser particles, the recovery drops very quickly (Gaudin, Groh & Henderson, 1931; Jowett, 1980). If the upper size limit can be increased for flotation, dramatic savings in the grinding energy can be achieved."

Jan 1, 2016

By J. T. Birkholzer, M. Rutenberg, K. -H. Lux, R. Wolters, J. Rutqvist, L. Blanco Martin

In this paper, we present numerical results corresponding to the Thermal Simulation for Drift Emplacement (TSDE) test, conducted in the Asse salt mine (Germany) between 1990 and 1999 to simulate reference repository conditions for spent nuclear fuel in rock salt. This test is of significant relevance for nuclear waste disposal in salt because extensive research and measurement programs were set up for the experiment. In our numerical study, we use two sequential simulators, TOUGH-FLAC and FLAC-TOUGH, and we investigate two-way coupled processes, focusing on thermo-mechanical analyses due to the main effect of heating. The two simulators used have recently been updated and are able to deal with large strains and creep processes. Moreover, specific constitutive relationships and coupling functions for rock salt and crushed salt under repository conditions are available. Within the framework of a benchmark exercise between Lawrence Berkeley National Laboratory and Clausthal University of Technology, the same scenario has been modeled in three dimensions using the two simulators mentioned. The main objective of the current, first stage of the benchmark is to evaluate the capabilities of these two simulators to predict relevant processes under repository conditions for high-level nuclear waste in saliniferous media. The comparison of the numerical predictions between them is very satisfactory, leading to a successful code-to-code verification. The comparison between measurements and numerical results shows that the most important processes are captured by the codes and constitutive models used. However, some differences exist between measurements and numerical results. These differences will be addressed in the next stage of the benchmark exercise, in which a parameter fitting effort will be undertaken. Overall, from the results obtained it can be concluded that TOUGH-FLAC and FLAC-TOUGH have the necessary capabilities to reproduce relevant processes under repository conditions for high-level nuclear waste in saliniferous formations.

Jan 1, 2015

By R. P. Smith

PRIOR to June, 1937, the employees of Hollinger Consolidated Gold Mines, Ltd., at Timmins, Ontario, received medical care for themselves under a contract system developed through an agreement between the employer, employee, and a contract physician. This form of practice is common to the mining industry in Ontario. But with the improvement in mining methods and conditions of living, and through an increasing demand for provision of a complete medical care, it was not any surprise when the employees of the Hollinger mine approached organized medicine and indicated their desire for a plan to provide their families with a more or less complete medical service in addition to that supplied for themselves. In April, 1937, this approach was made, and on June 18th, 1937, the Hollinger Employees' Medical Services Association was formed and started to provide medical services. A review of five years' experience is now presented. The Association provides complete medical service for the employee, his wife and family, as well as those dependents who are the total responsibility of the employee. The employee membership is limited to employees at the Hollinger mine in Timmins who reside in the immediate vicinity. The employee is examined by a Company doctor on application for employment and is subject to further examination by a specialise in chest diseases under the direction of the Workmen's Compensation Board of Ontario. The wife and family are not subject to examination but have to be registered when the employee is accepted for employment. The dependents, other than the immediate family, are subject to medical examination and approval after the employee has applied for such dependent or dependents to be admitted. Membership in the Association is obligatory when the employee is hired, but at the end of any Association year he may drop out if he so wishes.

Jan 1, 1943

By Phillip J. Mackey, Susumu Okabe

Copper mining and smelting has been carried out in Japan for over 13 centuries and in fact stretching back into antiquity. In 1889, the first electrolytic copper refinery in Japan based on Elkington’s principles was started by Furukawa Mining at Honjyo in downtown Tokyo based on the multiple or parallel system. Within two decades, a number of other copper refineries had begun operation. Interestingly, but perhaps not surprising given Japan’s long history of copper production, this first refinery in Japan commenced just ten years after the first refinery in the USA (1879), and not long after the first plants in Europe. By 1935, as a result of growth in copper demand, there were six domestic copper electro-refineries in Japan with an installed capacity of 97,800 tonnes/a, while actual production was 71,200 tonnes/a. Since about 1932, the majority of these plants were based on the more common parallel or multiple system. In 1946, just after World War II, domestic production capacity had dropped considerably to 29,000 tonnes/a, however with reconstruction, capacity and production expanded rapidly, with production reaching 81,000 tonnes/a in 1955, 187,000 tonnes/a in 1960 and 307,000 tonnes/a in 1965. The introduction of the first refinery and the early ones that followed and subsequent developments are discussed in this paper. The major technical achievements during the high growth period from 1945 to 1963 included: the use of fire- refined anodes; the introduction of newly-developed rectifiers; the introduction of lead-lined or vinyl-lined concrete cells; improvements in the electrolyte heating system; application of improved anti-corrosion materials and the introduction of heat-insulating surface coverings. In 2018, Japan’s refined copper production totaled 1,595,000 tonnes of copper, with Japan ranking third in the world after China and Chile. INTRODUCTION In 2018, Japan’s refined copper production totalled 1,595,000 tonnes of copper and Japan ranked third in the world for refined copper after China and Chile (Wood Mackenzie, 2019). There are now eight copper refineries in Japan which provide Japan’s production of refined copper. These plants are listed in Table 1 (Wood Mackenzie, 2019), also showing the production trend since 2013; in general, production over this period has been relatively steady. The Toyo plant is now the 7th largest copper refinery in the world after several large plants as rated by capacity in China, Russia and India (ICSG, 2019).

Jan 1, 2019

By S. Fabich

Since the very beginning of Polish copper mining, special consideration of sink shaft techniques through highly saturated Cenozoic rocks was required. Shaft freezing has been chosen as a method to consolidate these rocks. Due to the rock mass structure and water inflow potential, shaft sinking without freezing was considered dangerous. In the course of time, rock mass freezing technology and experience were evolved and this technology became safer and more reliable. New techniques appeared not only in the technical method of freezing, but also in the matter of designing. Computer aided techniques allow engineers to make a detailed analysis and view of freeze wall development. Nevertheless it is important to determine basic thermal rock properties. In this paper, the evolution of knowledge and engineering experience taken in Polish copper mines and current knowledge level in that matter were shown.

Aug 1, 2013

By S. Balideh

A good understanding of the behavior of broken rock helps to make more informed decisions regarding slope stability and waste dump issues in mines. The cohesion coefficient of rock has little influence on the strength of broken rock; therefore, a criterion based on friction and cohesion of intact materials does not provide an accurate analysis for the strength of broken rock. This paper illustrates the effective strength of broken rock through a brief literature review about failure of intact rock and rock masses. The complete stress- strain curve and some important points of residual strength of rock are summarized in this paper.

Jun 1, 2012

By S. Borle

The microstructural features produced in friction stir welded AZ31, AZ80 and AZ91 alloys are examined when different welding parameters are applied. The microstructures primarily consist of a-Mg grains with a-Mg + Mg17A112 colonies, however melted films of Mg17A112 are produced in AZ91 alloy when high rotation speeds are applied. When the rotation speeds are slow, or the travel speeds are fast the Mg17A112 were incorporated into the stir zone, however they do not exhibit an elongated lamellar morphology associated with melted films. In the case of AZ80, the extruded base material contains a smaller fraction of Mg17A112 and few of these phases are observed in the stir zones. The results are explained based on the dissolution rate and melting temperatures of Mg17A112 controlling the overall morophology and fraction of phases in the stir zone.

Jan 1, 2011

By C. C. Allen, H. H. North

"The Young-Davidson mine is in the southeastern part of Powell township, in the district of Matachewan. It is 32 miles southwest of Kirkland Lake, 48 miles southeast of Timmins, and 25 miles by road Northwest of Elk Lake. The Young-Davidson and its neighbour, the Matachewan Consolidated mine, are the two present producing properties in the district. The Matachewan area is the southwestern extension of the Kirkland Lake belt or 'break'. The Young-Davidson mine since coming into production in 1934 has been operated by Hollinger Consolidated Gold Mines, Limited. ""Desultory prospecting(1) has been carried on in the Matachewan area from time to time since the discovery in 1906 of silver in James township at Elk Lake, and some gold has been found in the southeastern part of Alma township and in the central part of Cairo township. The first real interest in the area, however, was started by Jake Davidson's discovery in 1916 of gold on Davidson creek, on what is now part of the Young-Davidson property, and by Sam Otisse's discovery shortly afterwards on claims a short distance to the east, now part of the Matachewan Consolidated property. In subsequent years both of these properties were investigated by various companies; the Young-Davidson chiefly by the Porcupine Gold fields Development and Finance Company, Limited, and the Matachewan Canadian by the Colorado-Ontario Development Company, Limited, which in 1919 was reorganized under the name of Matachewan Gold Mines, Limited. Work was discontinued as the ore was considered too low in grade to be mined"". However, in 1933 Hollinger Consolidated Gold Mines, Limited, undertook to bring the property into production and this became a reality in 1934.The total production to the end of year 1945 was 319,185.59 oz. gold and 73,541.94 oz. silver from 3,228,845 tons of ore. This represents an average grade of $3.67, including exchange and premiums."

Jan 1, 1954

By Max W. Ball

YOU have been kind enough to ask me to speak to you on "The War and Anglo-American Relations." A speaker always takes the liberty of putting his own interpretation on the scope of his subject. I am going to exercise that privilege, and try to look back over a generation of Anglo-American relationships and forward beyond the present war. I should like particularly to consider responsibilities as well as relationships. A more accurate caption for what I am going to say would be "Anglo-American Responsibilities.?? THE WAR WILL BE WON I am assuming that sooner or later we shall win this war. History and economics point to the same conclusion, that Germany has attempted the impossible and that the seeds of defeat are already sown. As to one ecof1:omic factor, I am already on public record as believing that Germany's oil supply is inadequate for the war she has launched. That opinion is unchanged. Aside from such tangible factors, moreover, I am convinced that the spirit of freedom is unquenchable, and that no combination of powers will be able to rout it from the British Commonwealth of Nations and the United States. Stronger even than this conviction is my faith in a God who will not suffer the defeat of man's aspiration to be master of his own soul. I am sure that all of you share that faith, and that we need not argue it. We can start with the assumption that the war will end in victory. The subject we are to consider, then, is the relationship of the English-thinking peoples during the conflict, and their joint responsibilities in the difficult days that will follow it. A CANADIAN-AMERICAN No talk on such a subject is worth listening to unless the audience knows the background and fundamental beliefs of the speaker. No human statement stands alone; behind and beside and within it are the ideals and the bias of the man who makes it. Because I am a stranger to most of you, I am constrained to talk about myself before I talk about more important matters. The review may be profitable, not because of the subject, but because it may illustrate the evolution of an attitude toward England.

Jan 1, 1941

By P. Chollet, A Constant

THE RESULTS of a previous investigation ( 1) on the work-softening of some heat-treated steels have led to the conclusion that the occurrence and intensity of the phenomenon is possibly governed by the work-hardening capacity of the material, and the relative amount of retained austenite. The first assumption is compatible with Polakowski's theory (2) that the absence of work-softening, in steels quenched and tempered at relatively low temperatures, may be attributed to the high rate of work-hardening which compensates for, and even out-weighs, the loss of internal energy associated with the simultaneous rearrangement of the original system of internal stresses. Indeed, Polakowski first considered the work-softening as a manifestation of a partial release (by cold-working) of the latent strain energy stored in

Jan 1, 1962

By D. G. Sinclair

IN surveying the changes that have taken place in the mining industry of Ontario in the past ten years, the striking growth of the gold mining industry first attracts attention. In 1925 there were only twelve regularly producing gold mines in the Province, six of which were located in the Porcupine area, four at Kirkland Lake, and one each at Larder Lake and Boston Creek. In contrast with this, the year that has just closed (1935) has seen production on a steady basis from forty mines, with what may be termed spasmodic production from twelve other properties. This so-called spasmodic production is, however, responsible for the recovery of gold to an estimated value of between $75,000 and $100,000 during the year. Further illustrating the expansion in the gold mining group is the activity in the exploration and development of properties. In 1925, mining operations were conducted at 29 properties which had not reached production, while in 1935 work of this nature was carried on at 87 such properties. It is of interest to note that of the six properties listed as producers in Porcupine ten years ago, five are still producing at rates considerably in excess of the tonnages handled at that time. In fact, the estimated tonnage treated at these mines in 1935 exceeds the 1925 tonnage by approximately half a million tons. In Kirkland Lake, the figures are still more striking. The four mines in production in that camp in 1925 milled 346,584 tons, producing bullion to the value of $5,132,128, while in 1935 these same mines treated approximately 1,643,000 tons, with a recovery of roughly $29,300,000. While Porcupine and Kirkland Lake remain the great gold-producing camps of the Province, the growing importance of the newer areas is readily appreciated when we consider that in 1935 the mills of these areas treated over 1,000,000 tons of ore for a production in excess of $7,500,000. Pro-duction from these newer districts first became of importance in 1930 with the commencement of recovery at the Howey mine, in Red Lake, and the Minto, in Michipicoten. Since 1930, eighteen new gold mills have gone into production in the Red Lake, Little Long Lac-Beardmore, Pickle Crow, Sturgeon Lake, Michipicoten, Sudbury, and Matachewan areas. In respect to silver mining, the period under review has seen a considerable slackening of activity, due to a generally unstable and depreciated price for the product and to the exhaustion of ore reserves in the mines.

Jan 1, 1936

By Francois Charette

Corrosion is a significant factor affecting the capacity and working life of ground support. The paper explores a relatively simple method to predict the load capacity of a support system using a Monte Carlo stochastic approach. The analysis uses published field data on existing ground support to evaluate the applicability of the method and its predictive performance. Discussion on corrosion rates found in the field and predicted from laboratory measurement is provided.

Jun 1, 2012

By Corby G. Anderson

"Laboratory testing using industrial electrowinning solutions was performed to determine the best Faradic cell efficiency for copper cathode recovery. The variables tested were solution flow rate, recycle ratio, reagent addition combinations of guar and thiourea, and addition amount of acid mist suppressant CAL FAX DBA-70. The ideal flow rate was determined to be 37.85 litre/min. Additionally, the ideal recycle ratio was determined to be 10:1. The reagent addition scheme from testing which showed the highest efficiency was with 680 g/tonne guar of cathode copper won and with 135 g/tonne thiourea of cathode copper won. These values for reagent addition only reflect the best efficiency and should not be assumed to be the best reagent concentration for copper purity. The amount of foaming agent that showed the best efficiency was the test with 2 ppm of foaming agent. Again this amount of reagent is based on efficiency and should not be taken as the amount of reagent that does the best acid mist suppression. Additional proprietary surface characterization work indicates these additives may have enhanced the cathodic reduction surface morphology of some noble minor impurities. Subsequently, these operating parameters were introduced into the plant operation and proved successful after their implementation.BACKGROUNDCopper electrowinning has become a dominant technology for the production of marketable high grade copper cathode products. The literature is robust with applications, optimizations, additives and developments in this field (e.g., Classens & Harris, 1990; Pfalzgraff, 1999; Tozawa, Su, & Umetsu, 2003; San Martin, Otero, & Cruz, 2005; Houlachi, Edwards, & Robinson, 2007; Romero, Avila, Fester, & Yacher, 2007; Marsden, 2008; Beukes & Badenhorst, 2009; Vainio & Weatherseed 2009; Bender, 2010; Joy, Staley, Moats, Perkins, Uhrie, & Robinson, 2010; Khouraibchia & Moats, 2010; Moats, 2010; Rutledge & Anderson, 2015).Tests of forty hours duration and at room temperature were performed for this project using samples of actual industrial electrowinning solutions. These industrial solutions were comprised of 60 g/L Cu plus 65 g/L Ni, 3 g/L Fe, and 30 g/L free sulfuric acid. Other confidential minor impurities were also present including some solubilized precious metals. The testing apparatus utilizing stainless steel anodes and cathodes is illustrated in Figures 1 and 2."

Jan 1, 2016

By Burrows. A.

Temperature profiles in the lead smelter sinter bed at Xstrata Zinc Mount Isa sinter plant have been measured using a wireless temperature probe. Corresponding sinter samples have been collected for characterization. The sinter peak bed temperatures were found to be in the range of 1000 - 1200 °C. Microstructures and softening temperatures of these sinters have been characterised. Strong correlations have been observed between peak bed temperature and peak hood temperature, and between mean sinter softening temperature and peak bed temperature. It was found that higher peak bed temperature results in higher sinter softening temperature. For the feed material used in the trials, to obtain sinters with mean softening temperatures above 1050 °C, peak bed temperatures above 1130 °C are required. There appears to be a direct correlation between granule size distribution in the feed and peak bed temperature attained. High peak bed temperatures are observed in sinters with narrow granule size distribution.

Jan 1, 2008