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By M. Abouhamad

According to the Canadian Urban Transit Association (CUTA), 140 Billion CAD is required to maintain, rehabilitate, and replace subway infrastructure between 2010 and 2014. The current practice adopted by transit authorities for prioritizing subway stations for rehabilitation is based on the station structural needs. While this classification is reflective of station condition, other factors, such as station size, location and passenger capacity, play an important role. The criticality of a station is an index that represents the functional importance of a station depending upon a set of identified factors. The system criticality is based on several attributes, such as station location, size, and nature of use. This paper presents a novel method of clustering subway stations for rehabilitation priority based on their criticality level. The different stations in a subway network are rated according to their relative importance against predefined attributes. The weights and scores of the attributes are computed with the help of experts and current subway network data. The analysis is done using the Fuzzy Analytic Network Process (FANP) to accommodate the subjectivity of human judgment as being expressed in natural language which entails ?fuzziness? in real-life problems and account for the interdependency between the selected attributes. The output of the model is a criticality based clustering of subway stations. The proposed framework helps authorities prioritize stations for rehabilitation and highlight stations with more criticality for a more robust asset analysis.

Aug 1, 2013

By Inga Tuzovskaya1i

Three types of gold species were observed for gold-zeolites, prepared by reduction of ionexchanged Au species in a series of zeolites: (i) Au3+cations, (ii) neutral Au0 n or charged Aus+ n clusters suggested to be inside the zeolite channels, (iii) Au nanoparticles with diameter varied from 2 through 20 nm located on the external surface of zeolite microcrystals. Contribution of the gold species formed in zeolite after the ion exchange was found to depend on zeolite type, acidity of zeolite, temperature of reduction and time of storage of the exchanged and reduced Au-containing zeolites. Au3+ ionic species and clusters Aun were formed after the ion-exchange procedure (in contrast with the familiar production of Agn in same zeolites). Gold nanoparticles were observed only as the result of reduction of the Au-exchanged forms at elevated temperatures due to reduction of Au3+ species and aggregation of clusters.

Oct 1, 2003

By P. R. Warner

This paper reviews the development of certain aspects of the electrical specifications of Anglo American?s suite of specifications for gearless mill drives (?GMDs?). These specifications are based on experiences in both Anglo American?s and others? operations, benchmarking against large hydro generators, the advice of industry and university experts, and continuous close co-operation with OEMs. To achieve a step change in availability additional final testing and electrical protection have been implemented, insulation requirements have been specified for machines to be operated at high altitude and clean area and access control systems have been developed.

Nov 1, 2011

By J. E. Dutrizac, R. J. C. MacDonald, J. B. O'Reilly

"Sometime around 3000 B.C., primitive metallurgists working in the mountainous regions of Asia Minor bordering on the Black Sea (Pontus) produced a soft, easily fused metal today known as lead. It appears certain that the first metal was made by reductive smelting of galena, but whether this recovery arose by the accidental inclusion of galena in the stones of a fire hearth or whether it occurred as a consequence of simple pyrometallurgical experiments on a series of interesting ""stones"" will likely never be known with certainty. The properties of galena, high metallic lustre, great density and facile cleavage, must have excited the ancients, and such ""stones"" would have been the object of primitive testing111 - Shortly after the discovery of lead, the ancients found that the controlled oxidation of this metal at elevated temperatures yielded smaller amounts of a more interesting material, silver. Again, it is uncertain if the production of silver by primitive cupellation techniques was the result of a fireside accident or the consequence of a deliberate experiment, but the important fact is that silver was produced shortly after the discovery of lead. The techniques for making lead and silver spread gradually throughout the entire civilized world, likely as a result of both technology diffusion and independent rediscovery. The physical properties of lead could not have been overly attractive to the ancients, but silver was a different matter altogether. The gleaming white lustre and relative immunity to oxidation quickly assigned silver to the precious materials category, a status it still enjoys. In early times, argentiferous galena was inevitably processed only for its silver values; lead was generally an unwanted byproduct and was frequently discarded as litharge (PbO) during the cupellation process. The silver was eagerly sought, however, and resulted in considerable mining activity culminating in the famous Athenian silver mines at Laurium at the southern end of the Athenian peninsula."

Jan 1, 1999

By E. Godfrey

The average man one meets on the street thinks of an explosive as a medium of death and destruction, something unstable which should be given a wide berth, because he knows little or nothing about its use or its stability. Briefly, explosives are compounds that develop very large quantities of heat and gas in an extremely short time and in a small space, thereby exerting enormous pressure upon surrounding bodies, and by the rapid expansion of this highly heated gas are able to perform a considerable amount of useful work. The amount of heat generated and the volume of gas produced by the decomposition of an explosive determines the amount of mechanical work it can do, and the time occupied by its change from solid or liquid condition to gaseous condition determines its shattering effect. Explosives manufactured by reputable people are not extremely dangerous, on the other hand they are quite safe if handled in a proper manner. Furthermore, before an explosive can be placed on the Canadian market a sample must be submitted to the Explosives Division of the Mines Department, who may condemn or permit its manufacture, according to their findings regarding its safety in handling and its stability during storage.

Jan 1, 1926

By M. Bélanger, H. -L. Jacob

"The province of Quebec has a strong tradition in industrial minerals. Ten commodities are produced and the annual total shipments have exceeded $600 million in recent years. Quebec is a world renowned producer of chrysotile, titanium slag, graphite, and ilmenite. Quebec is an important North American producer of mica, talc, and peat moss. This paper reviews the main minerals and commodities that have been the object of exploration or development in recent years, namely graphite, wollastonite, dolomite, and silica. Some of the leading projects concerning magnesium minerals and apatite-ilmenite are described. IntroductionQuebec has a strong tradition in industrial minerals. It goes back to the second half of the 19th century when the first graphite and apatite mines in the Gatineau area and asbestos mines in the Eastern Townships were opened. Since then, more than 25 commodities have been produced in Quebec, making industrial minerals an integral part of the Quebec mineral industry. Today, industrial minerals and building materials count for one third of the total mineral production in Quebec.Present industrial mineral production includes 10 commodities (Table 1). In the last five years, the value of industrial mineral shipments has varied between 500 and 700 millions dollars annually, which represents 20% to 25% of Quebec’s total mineral production. For many years, Quebec has been a major producer of chrysotile and titanium slag, the only producer in eastern North America of mica, graphite and ilmenite, and a leading Canadian producer of talc and peat moss. Quebec also produces, mainly for domestic markets, dolomite, limestone, salt and silica.Quebec’s industrial mineral sector has been quite active in the recent years. Exploration by government geologists and companies has led to the outlining of new deposits, some of which are now in production; others are currently being evaluated. Technical and economic studies are also underway to determine the feasibility of various development projects."

Jan 1, 1999

By T. T. Wang, T. H. Huang, Y. C. Chiu

Quantitatively analyzing deformation of a tunnel with lining anomalies for structural safety evaluation is essential for sustainable tunnel engineering. However, a complete theory and associated methodology accounted for displacement of a built tunnel is absent. This manuscript introduces a novel characteristic matrix method proposed by the authors which is an integrated procedure that analyzes displacement of rock tunnels in operation. First, establish a numerical model expressing a specific state of the tunnel in interest. Derive the characteristic displacement modes by a unit disturbances and check their independency. Once the characteristic displacement modes are proved to be orthogonal (independent), they are ready for use. Given a tunnel displacement, modal decomposition returns the magnitude of each characteristic displacement modes that together consist the given displacement. By realizing the definite value of horizontal and vertical translation, rotation, uniform compression/expansion, elliptic deformation, triangular deformation…etc. for a tunnel displacement, one can distinguish tunnel displacement and deformation types from their modal composition. A circular tunnel with elastic structure and surrounded by elastic rock mass is chosen to demonstrate the outcome of characteristic modes and how they work. The influences of tunnel shape, elastic modulus ratio between rock mass and tunnel structure, and numbers of monitoring points on a tunnel profile were also discussed. Identifying possible tunnel deformation causes is attainable if further connections between mode combination and force increments were built.

Jan 1, 2015

By G. A. Sutton

This paper, describes a case example from San Manuel mine, where in situ copper leaching of the supergene zone was done over a 14 year period (1986–1999) in conjunction with underground and open-pit mining operations of a copper porphyry deposit. In 1993–1994, testing of well fields was done to determine the amount of copper that would be recovered from in situ leaching of the supergene zone, which was composed primarily of chrysocolla and copper-clay minerals. It was determined that the leach fluid would reach 70% (‘sweep efficiency’) of the copper minerals and that 75% of them would be leached for a recovery of 52% of the acid soluble copper. However, the final results from Zone 6, which had the longest leach history, showed that approximately 42% of the acid soluble copper was recovered, indicating that the `sweep efficiency’ was closer to 55%. Comparison of drill-core assay data from two holes, one drilled before (ARM158) and the other after (SMO9607) leaching, also indicate that approximately 42% of the acid soluble copper was recovered. The discrepancy between the predicted (52%) and actual (42%) recovery is probably related to a combination of factors, including difficulty in maintaining fluid saturation, channeling effects and gypsum precipitation. INTRODUCTION In situ copper leaching at the San Manuel mine, Arizona, was initiated in 1986. It was recognized that some of the copper oxide resource was not going to be economically recoverable by conventional open pit and heap leach methods using solvent extraction and electrowinning (SXEW). A high stripping ratio would be required to access part of the resource. At the time, in situ leaching was becoming popular in the uranium industry but the approach was virtually unknown in the copper industry, especially not at a large scale.

Jan 1, 2019

By C. Samuelsson, H. Ahmed, B Björkman, A. Andersson

The cost of raw material and energy is a continuing driving force towards working with increasing the recycling of ore based steelmaking residues. In Sweden no on-site sinter plants are operated at the integrated steelworks. Instead, selected residues from the plant are incorporated in a cold bonded briquette product which is recycled to the process via the blast furnace (BF). Since the BF sludge is the major bleed of zinc out of the furnace it is required to be de-zinced prior to recycling in the briquette product. In the present work landfilled BF sludge has been characterized with respect to chemical composition, particle size distribution, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The sludge was also subjected to laboratory scale hydrocyclone trials aiming at reducing the zinc content making the sludge viable for recycling. The results suggested that the sludge had been agglomerated prior to the characterization and hydrocyclone treatment. The zinc removal using the hydrocyclone was discussed.

Jan 1, 2015

By J. P. Norrie

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

Jan 1, 1931

By Y. Thibault, L. Morin, R. Cameron, D. Gould

"There are an estimated 50 to 100 million dry metric tonnes of low-grade nickeliferous pyrrhotite tailings in the Sudbury area alone, with an average nickel grade ~0.8% (plus cobalt). Pyrrhotite is a highly reactive sulphide mineral that has the potential to generate acidity; consequently, it is stored in large tailings ponds that require perpetual treatment to avoid the production of acidic drainage. Re-processing this material using bioleaching technologies has the potential to recover valuable metals, while reducing the toxicity, reactivity, and acid generating potential of the remaining residues. CanmetMINING is currently developing a stirred-tank bioleaching process to recovery nickel and cobalt from pyrrhotite-rich tailings. Stirred-tank experiments have been conducted with one tailings sample over a range of pH and temperature conditions, resulting in 80 to 90% and 70 to 80% leaching of nickel and cobalt respectively in 10 days.INTRODUCTION Sulphide tailings may represent a significant financial liability for mining companies as these wastes may produce acidic drainage under some disposal conditions. As a result, the companies must post financial bonds large enough to ensure there are sufficient funds for perpetual management of these wastes. At the same time, there are billions of dollars in metals incorporated into these mining wastes waiting to become valorized. Many sulphide tailings are amendable to bacterial oxidation for metal extraction. Re-processing of tailings using bacterial leaching has the potential to recover valuable metals from waste; and reduce the toxicity, the reactivity, and the acid generating potential of the remaining residue. By reprocessing these wastes there is an opportunity to significantly reduce liabilities and financial assurance bonds, while recovering metal values. There are an estimated 50 to 100 million dry metric tonnes of low-grade nickeliferous pyrrhotite-rich tailings in the Sudbury area alone with an average nickel grade ~0.8% (Peek et al., 2011) plus cobalt and copper. Pyrrhotite is separated from pentlandite concentrates by magnetic separation and flotation. It is already finely ground and has often been segregated from other tailings material, making „mining? relatively inexpensive. This represents roughly (> $100/ton) in contained value, with negligible mining costs. This paper reports on the development of a stirred-tank bioleaching process for recovering nickel and cobalt from pyrrhoitite-rich tailings, which is currently underway at Canmet MINING."

Jan 1, 2017

By A. Probst, N. Moores, J. A. Finch

"In 1994 McGill and INCO (Sudbury operation) initiated transfer of technology originally developed to detect level in flotation columns to thickeners. A conductivity probe was installed in a concentrate thickener to monitor the mud-line and solids load. The probe consisted in a vertical tube with 32 equally-spaced electrode rings connected in pairs to give 31 conductivity cells. Conductivity was measured as a function of depth (so-called conductivity profile) from which the mud line and % solids could be inferred. The probe was installed in October 1994 and has been successfully detecting profiles since then. This communication includes a description of incidents and experiences during this technology transfer process including: probe installation and start-up; software modifications to accommodate operating conditions and operators' needs; calibration procedures to adjust to changes in performance as a consequence of long term use; and preliminary observations on the last stage, still in progress, signal interpretation and use to facilitate operation, particularly by providing early reaction to upstream disturbances.IntroductionThickening is one of the basic unit operations in mineral processing and hydrometallurgy used to separate suspended solid particles from a solid-liquid dispersion by gravity settling. As the dispersion enters the thickener, the solids settle and clarified water overflows the top. A thickener, which may be continuous or batch, is basically a large vertical cylindrical tank provided with devices to feed the dispersion and to remove the settled solids. The tank provides residence time for the particles to settle. The dispersion enters the thickener through the feedwell whose function is to dissipate the momentum of the feed stream and to create relatively quiescent conditions around the entering point. Rotating rake arms move the settled solids towards the discharge point located at the bottom centre of the tank.There are normally three distinct zones in a thickener: a top layer of clear water, a middle layer called a sedimenting zone in which particles are settling, and a bottom layer called a compression zone in which particles are pressed together as a consequence of the weight of accumulated particles. Proper operation of a thickener requires two simultaneous conditions: no solids in the water overflowing the top and the target solids content in the underflow pulp. To achieve these conditions is difficult because sensors for detecting the sediment line (interface between clear water and sedimenting zone) and the solids content in the compression zone are not commercially available."

Jan 1, 1998

"HPGRs operate in a wide array of applications in mining and minerals. These range from relatively coarse crushing of copper and gold ores at one end of the spectrum to the processing of fine iron ore pellet feed and fine industrial mineral products at the other. Traditionally these circuits involve the treatment of relatively moist materials in pre-grinding circuits; using single stage HPGRs in open circuit or as a closed circuit operation with screening or partial product recycle. More recently, HPGR is increasingly deployed in dry grinding in combination with air classification. The high throughput demonstrated by larger HPGRs has stretched the application towards coarser size reduction duties for a number of new projects. At the same time, the basic principle of inter-particle crushing for generating a product with a high fines proportion gives ground to investigate applying the technology further towards finished product duties. The advantages that HPGR brings are clear. Multi Stage grinding enables energy efficient size reduction across more of the comminution circuit. Primary HPGR serves for a coarse grinding duty, whereas a secondary HPGR is geared towards generating a fine product for downstream processing or even a finished product. This publication summarizes some of the features of staged HPGR circuits and discusses some examples of operating and projected applications.INTRODUCTION In most HPGR applications, the grinding units are used as a single process stage, either in open circuit, such as for pebble crushing [Rose 2002, Westermeyer 2000, Van der Meer 2015] or in closed circuit with classification [Van der Meer 2009, 2012] or product recycling [Van der Meer 2010]. Where a higher plant capacity is required, the HPGRs are commonly installed in multiple lines in a parallel arrangement [Parker 2005, Koski 201, Vanderbeek 2006]. HPGRs can take a wide range of feed size distributions, and grind this down to a product with a high fines content. In general view, there is a limit on the size reduction range that even an HPGR can provide. Grinding down from a very coarse ore (e.g. 70-100 mm) to a very fine product (e.g. 100 microns range) is stretching the ability of a single stage HPGR circuit. Fine grinding generally requires a classification stage that returns the classifier oversize to the head of the HPGR circuit. From one point of view, it can be demonstrated that when recycling a large proportion of fines and middlings back to the HPGR feed results in an effective feed with an overrepresentation of middlings and fines, which will eventually reduce the grinding efficiency and consequently result in an increased recirculation mass flow [Van der Meer 2014]. From another point of view the large recycling mass puts a strain or even a limit on the capacity of present-day conveyor capacity."

Jan 1, 2018

By Charles Tkaczuk

In order to remain competitive the mining industry must keep up with changes in technology. Many innovative technologies from the mining perspective are commonplace in other industries. A ?Global? review of technologies will often reveal existing technologies that can be innovatively applied in the mining industry. Industries, which are rife with proven solutions include, medicine, biotechnology, security, manufacturing, telecommunications, etc. This paper addresses the communications aspect of mining where greater productivity, lower costs and the ability to quickly react to mining related events is obtained through an increase in remote monitoring and operating control. A review of the communications systems in place globally reveals technologies that, with minimal modification, can be immediately applied to the mining environment. We discuss the concept, advantages and implementation of existing communications technology from an industry that is not usually associated with the mining industry. This technology will form the basis of a solid platform on which can be built a state-of-the-art process monitoring, control, and communication system. This lays the groundwork for providing one solution to the underground mining industry?s most difficult problem, establishing a reliable, maintainable and cost-effective underground bi-directional wired/wireless data, video and analog communications system. We need look no further than our own doorsteps to find such a solution. The cable that you see coming from the simple green or brown box on the boulevard into your home contains hundreds of television broadcast channels, FM radio channels and data channels. And if you have a set-top box, you are in control of it all. The Cable Television Broadcast Distribution System suppliers of today are at the leading edge of converging all the different methods of communications onto a common carrier, coaxial cable or fibre optic cable. There is no fundamental difference between providing a reliable communications network to a city/neighbourhood/home/personal computer than there is to a mining operation/underground level/equipment or person. The principle is the same. Only the application is different. Realizing this, we can capitalize on the efforts of other industrial sectors, to solve our communications problem. Where else can you find a solution to a problem that is mature, having been developed with the input of thousands of engineers, and having hundreds of millions of dollars spent on research and development, manufacturing, distribution, global presence and engineering support?

May 1, 2003

By R. E. Evans

This paper contains an analysis of the geography and geology of the Black Lake area, Eastern Townships of Quebec, an outline of the work to be performed, an explanation of the design concept and how it was developed, and a discussion of the actual stripping operation, including details of the machinery being used, etc.

Jan 1, 1967

By Z. -E. Nakagawa, O. Yamamoto

After the formation of a concentration gradient of SiC within C-C composite, either zircon or mullite thin films were coated on the surface by sol-gel process. Oxidation resistance tests of as-prepared composites with a couple consisting of a ceramic thin film and a SiC-gradient were then carried out in air at the temperature range from 600 to 1600°C. By the coating of zircon with a thickness of 1.5 µm, a pronounced oxidation resistance was observed; the mass loss by oxidation was almost negligible at 1000°C and one hundredth of original composite at 1400°C. In the case of the coating of mullite with a thickness of 1.0 pm, the marked improvement in oxidation resistance over the whole temperature range examined, from 600 to 1600°C, was found with the combination of a SiC-gradient and a mullite thin film

Jan 1, 2004

By Ralph L. Rutherford

Introduction During the past twenty-five years we have seen considerable exploration for oil on the plains of southern and east-central Alberta. This exploration has to some extent gone on in cycles, with periodic starts, stops, and occasionally some reversals. Each major attempt is usually supplemented by the application of some new method of exploration and, following each period of exploration, drilling tests are made. Whereas oil-bearing horizons are the ultimate objective of these explorations, the preliminary investigation frequently aims at a discovery of structure based on the long accepted belief that accumulations of oil and gas are to a marked degree structurally controlled. At the inception of this general exploration for oil, it was natural that attention should be directed to areas where there was surface evidence of deformation of the underlying strata, but, as the programme progressed, it was found that these surface manifestations of structure were often deceptive when attempts were made to project them to depth, to involve the deeper strata. Drilling of test wells was the only satisfactory method of obtaining exact information.

Jan 1, 1946

By D. Virely, M. Gasc-Barbier, J. Guittard

"The valleys of the Dordogne and the Vézère (France) have been inhabited since prehistoric times, as evidenced by the famous site of Lascaux. A few miles away, the village of La Roque-Gageac is also a very popular tourist destination (about 1.5 million tourists per year): The village is sandwiched between a massive limestone cliff and the Dordogne river. The collapse of a cave roof high above the village in January 2010 led us to characterize instability together for the cave and the whole cliff and propose a adapted instrumentation to monitor the fracture openings in the rock mass that are linked to climatic variations. Measurements have been going on and been recorded for nearly 4 years. They point out the role of thermal stress fatigue in the breakdown of the rock mass. In this paper we describe the site under study, the instrumentation and its main results. INTRODUCTIONThe phenomenon of thermal fatigue has been very little studied as far as rocks are concerned, whereas it is rather well characterized for other types of materials: Elsevier published a journal dedicated to fatigue (International Journal of fatigue). In the case of rocks, thermal phenomena and their impacts on mechanical behavior have been analyzed from a micro-structural point of view, and it is now well-known that an increase in temperature causes a dilatation of crystals (Arnould et al., 2004; Berest & Weber, 1998). This dilatation may lead to the development of inter-granular traction and compression stresses, and if those stresses are greater than fracture strength, inter-granular and intra-granular cracks may take place. On the other hand, the fatigue phenomenon (cyclic repetition of a temperature variation which is less extreme than the one that may lead to this inter-granular or intra-granular fracture) is a phenomenon which has not been much studied.The principal studies on thermal fatigue on rocks come mainly from the field of geomorphology, particularly in connection with the analysis of the evolutions of past climate that can explain the present shapes of those landforms: those studies remained essentially qualitative and not quantitative. Le Ber & Oter Duthoit (1987) proposed a thermal and thermodynamic approach to analyse the disaggregation of rock masses. This analysis is dedicated to the study of paleoclimates and was implemented to better understand the formation of slope deposits in order to propose transfer models permitting the reconstruction of the climactic conditions contemporary to their appearance. Since deterioration in the cliff only appears after several cycles, it means that it is a gradual and irreversible deterioration which leads to an increase of the « disorder ». Seen from a macroscopic system point of view, this irreversible evolution is quantified by the internal creation of entropy."

Jan 1, 2015

"Real-time, on belt analysis of minerals is becoming increasingly important and critical in modern operations, especially in the mine-to-mill. Prompt gamma neutron activation analysis has long been utilised for real-time elemental analysis in bulk materials, with Scantech's GEOSCAN being the instrument of choice in the minerals sector. Working in the minerals space for 15 years, the GEOSCAN has been successfully implemented in a wide range of minerals applications including iron, copper, lead-zinc, manganese, phosphate and more, and it caters for the very high demands and increasing requirements of a contemporary processing facility. An area of focus has been on increasing the analysis frequency to allow for rapid analysis results with the same high degree of accuracy typically expected of the GEOSCAN. This paper discusses the underlying research and technology that has enabled such rapid analysis and presents a range of examples using a thorough statistical approach on real production material, demonstrating achievable accuracy over a short analysis time, and dispelling common myths about the speed of the technique. Potential applications are discussed to conclude the paper.INTRODUCTION Technology and the information it can provide plays a critical role in the evolving modern mineral processing landscape. The importance of technology to analyse various features of ores and concentrates being processed is obvious, and recent years has seen the advance of numerous technologies to provide a variety of real-time measurements on conveyed material flows. From sampling apparatus to particle size analysis to weight and density meters to full elemental analysis, the availability of information enables a variety of improvements in the process leading to improved efficiency and increased revenue. To maximise the potential benefits, access to real-time information is imperative, and rapid updates of information become necessary to make appropriate process control decisions based on the most relevant and up-to-date information."

Jan 1, 2017

By S. A. Pence, A. I. McCallum, V. de Korompay

"Special salt protection rings containing a water-swell• able, polymeric sealant are in successful operation in Canadian potash shafts. Installed above the Prairie Evaporite salt formation at a depth of 3,000 feet, the sealant is preventing formation water migration into the salt and pressure build-up on the concrete lining of both production and service shafts. The salt protection rings are not under the hydrostatic pressure of the formation water.The chemical sealant in use has the unique property of imbibing water and swelling. •Therefore, any water at• tempting to flow by the seal ring actually produces a tighter seal.The purpose of this paper is to discuss the sealant and its properties and uses. Installation of the material and its operation in two Canadian mine shafts is described."

Jan 1, 1971