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By K. R. Nichol

The author points out that corrosion works 24 hours a day, every day. It is an economic reality that the cost of corrosion is inevitable and that its cost should be incurred in the least expensive way. An economic evaluation technique to properly assess its relative impact is the Discounted Cash Flow Method. Various remedial and corrosion control measures are available and these, when coupled with a planned corrosion control program, help reduce the cost of corrosion.

Jan 1, 1973

By Jim Cooney

Background ?1990s saw massive changes in South African mining industry ?over 100,000 jobs lost as the industry restructured; ?1999 ?Placer Dome purchased a 50% interest in South Deep (WAL), a mine located just outside Johannesburg ?This was the first major post-apartheid foreign investment in the South African mining industry The Situation ?Placer Dome decided to lay off 2560 mineworkers (one third of the workforce) from the South Deep Mine to restore the mine to economic viability. ?Unemployment in South Africa was over 25%, and the retrenched mineworkers had few skills with which to make a living. Policy Context ?Placer Dome was committed to: ?global corporate policy of Sustainable Development, ?demonstrating that its business contributes to the economic and social progress of host jurisdictions. ?Government of South Africa was committed to ?attracting foreign investment to its mining sector with a view to modernizing and enhancing its economic and social viability, ?ameliorating the negative social consequences of structural change without arresting the necessary process of restructuring. ?National Union of Mineworkers was committed to: ?working with the mining industry and the government in implementing a Code of Good Practice on Dismissals and a Social Plan to assist retrenched mineworkers (1999).

May 1, 2006

By Paul F. Grundy

The ever changing conditions in the coal-mining industry and the increasing competition of other fuels such as oil, natural gas, wood refuse, etc., have made it imperative that the coal operator be in a position to supply a constantly uniform and clean product. The old idea of putting on the market "anything so long as it's black" no longer holds good. Today's users of fuel have to consider the amount of heat per dollar they obtain from the fuel they buy. Burning of coal has become largely mechanical, at least so far as industrial coal is concerned, and industrial coal is the kind the bituminous operator is for the most part called upon to supply. When we get into things mechanical, the matter of precision has a mighty bearing on efficiency. Precision in coal means standardization of quality, or uniformity of preparation in size and also in ash and moisture content. The trend of coal mining is ever towards more and more mechanization. Mechanization means coal-cutting machinery, loading machinery, conveying machinery, etc. Although such methods cut the cost, the cleanliness of coal so mined and loaded is not controllable to the same extent as when each operation is by hand labour. The operator has therefore the problem of mining his coal as cheaply as possible, but at the same time preparing a product which will to the utmost satisfy his customer. The answer is a mechanical cleaning plant. Before installing a cleaning plant, however, the operator must take into consideration the cleansability of the coal from his particular mine. This is accomplished by taking representative samples of the seam or seams to be treated, and subjecting these to screen tests, followed by float and sink tests on each size product. From these tests, it can be readily found to what degree of cleanliness the several sizes can be prepared advantageously, and also what will be the percentage recovery of cleaned coal. The accompanying tables give the results of representative tests on Michel coals of minus-2-inch size. All coal over 2-inc.h was intended to be hand cleaned. The coal-cleaning plants in general use at the present time come under two broad classifications, namely, wet and dry.

Jan 1, 1934

By C. Jay Hodgson, Adrienne C. L. Larocque

The Mobrun VMS deposit in northwestern Quebec does not fit the classic Noranda type model, but exhibits characteristics more consistent with a Mattabi-type deposit. The orebodies are underlain by fragmental volcanic rocks indicative of explosive volcanism in shallow water. Felsic volcanic rocks are more abundant than mafic rocks. Alteration assemblages comprise chlorite, carbonate, sericite, and quartz. Broad semi-conformable alteration occurs high in the footwall to the 1100 lens. Mobrun occurs higher in the stratigraphic sequence than most of the other deposits in the Noranda camp. In this part of the stratigraphy, zones of pervasive carbonatization may be more useful guides for exploration than zones of silicification.

Jan 1, 1993

By John B. Riddell

"AN EXCELLENT review of the status of applied geochemistry was given by Warren (1959) at last year's General Meeting of the C.I.M. The purpose of this paper is to present recent developments and trends. Several important books were announced during 1958: Ginzburg, I. I. Principles of geo-chemical prospecting. (In process of translation from the Russian by V. Sokoloff).Vinogradov, A. P. The geochemistry of rare and zvidely scattered chemical elements in soils. Consultants Bureau, N.Y. Korzhinskii, D. S. Physicochemical basis of the analysis of the paragenesis of minerals. Consultants Bureau, N.Y.In addition to these translations Mason's Geochemistry' has been revised, and Hawkes and Webb (personal communication) are publishing a book on geochemical exploration. A Symposium on Geochemistry was head in Paris in July, 1957, in conjunction with the XVIth International Congress of Pure and Al-lied Geochemistry. The abstracts of the papers presented at this Symposium were published in Geochimica et Cosmocl1imica Acta, 1958, Vol. 14, pp. 150-167."

Jan 1, 1960

By Jeremy G. Berg, James B. Mulligan

"There is a very small fraction of wireless experts in the world with experience in underground installations and an even smaller fraction that have experience specific to building mine shafts. This is why in 2009, Redpath created its own system to meet the demands specific to shaft construction. Today, after a dozen shaft installations and several design iterations, Redpath has the expertise and experience required to implement a proper wireless system in any shaft configuration.This document will explain multiple proven wireless communication designs optimized for shaft construction and suitable for permanent use. This includes line of sight installations up to 1200m, short range mesh networks, and the latest patent pending Integrated Leaky Feeder Mesh Network. Additionally, this document will explore the lessons that Redpath learned in its effort to interconnect the people and tools needed to build a mine shaft.INTRODUCTIONAfter a decade of research, several design iterations and a dozen application examples, Redpath has resolved two wireless network architectures to best serve mine shaft construction projects.The long range line-of-sight (LOS) wireless network is the most cost effective and easiest to install, but requires an unobstructed line of sight between the working area and the shaft collar. As such, long range LOS is best suited for ventilation shafts or during the first phase of shaft sinking, before the shaft is equipped.Alternatively, a mesh network uses radios installed at pre-determined intervals in the shaft and on each conveyance. A wireless mesh uses antennas to bridge intervals between shaft radios, whereas Redpath’s integrated leaky feeder mesh network (patent pending) bridges these intervals with radiating cable, commonly referred to as a “leaky feeder” cable. Both of these mesh configurations can provide continuous reception for hoist conveyances travelling in shafts without line-of-sight, making them ideal for shaft equipping and even permanent installations in both mine shafts and lateral drifts.BACKGROUNDHoist operators receive operating commands using what are commonly referred to as “bell signals.” These instructions are delivered in a series of coded pulses on a spring returned pull cord or push button that is typically hardwired back to the hoist operator’s control room from one of many locations in the mine shaft. During the construction phase of a traditional mine shaft, a worker riding inside the sinking bucket would have to reach out to a pull cord installed on the shaft wall to send a stop command to the hoist operator. Today, Redpath’s modern shaft sinking projects use fully enclosed personnel carriers to protect the workers riding inside, specifically preventing workers from reaching out into the shaft while the hoist is in motion. The enforcement of this safety feature on all shaft projects in 2008 forced the engineering group at Redpath to find a suitable wireless solution for hoist communication to facilitate shaft construction.THE IDEAL COMMUNICATION SYSTEM FOR MINE SHAFT CONSTRUCTIONIdeally, the shaft communication system should not transform the tools to which the miners have grown accustomed. It should support the push-to-talk functionality of traditional VHF handsets and the standard belling system that has been used for decades. Additionally, it should be able to support a vendor independent framework upon which new devices and features can be added. The following paragraphs summarize some of the important requirements Redpath has identified.Support for voice transmission: Low latency is critical to prevent jitter during voice transmissions. The system must be compatible with commercially available mobile handsets and support several simultaneous conversations with the ability to broadcast a voice message to all users on a select channel using a “push-to- talk” microphone and loudspeaker.Transmission of PLC data: Low latency is required to"

Jan 1, 2019

By D. Bouchard, M. Forté, A. Charette

A transparent replica of a casting die was built to achieve a better understanding of the filling mechanisms of aluminum in high pressure die casting. Water and tomato paste were respectively used as analogues for the Newtonian liquid aluminum and the non-Newtonian semi-solid aluminum. The transparent die was installed on an industrial casting press and filling was filmed with a high-speed camera. Differences between the Newtonian and non-Newtonian fluids are presented and discussed.

Jan 1, 2006

By A. A. Holland

Introduction The world's largest known deposits of natural sodium sulphate (Glauber salt), generally termed 'alkali ' throughout western Canada, are located in the Province of Saskatchewan: reserves are estimated to exceed 200,000,000 tons. These are surface deposits resulting from the recent or present-day natural evaporation of brines, in which respect they are similar to those occurring in certain other parts of the world, as in semi-arid sections of the United States, Russia, Germany and Austria. In some areas, underground deposits formed hundreds of thousands of years ago have been _encountered in drilling, and indications are that they also were formed under arid or semi-arid conditions. The master key to the formation of deposits of natural sodium sulphate, wherever they occur, is a climate, either past or present, under which evaporation exceeds precipitation over a considerable period of time. Commercial development of the Saskatchewan deposits began about thirty years ago. Previously, the demand for sodium sulphate had largely been met by salt cake produced as a by-product in the manufacture of hydrochloric acid from common salt. The rapid increase in the production of Kraft paper and, more recently, the development of synthetic detergent materials, have caused a marked increase in the market for sodium sulphate. This chemical gives the extra toughness to Kraft paper and is used in detergent compositions in proportions as high as 75 per cent. Saskatchewan now has six commercial plants producing natural sodium sulphate. Production from each in the fiscal years 1947 and 1948 is shown in Table I. The newest and latest plant is that of Saskatchewan Minerals, at Chaplin, which 1s designed to produce up to 150,000 tons of salt cake, 98.5 to 99.5 per cent pure, yearly. This is equivalent to about 24 percent of the total United States production of crude commercial salt cake for 1947.

Jan 1, 1949

By L. Tikasz

The primary purpose of ore hauling model studies is to capture the variability of the ore delivery ? stockpiling process in order to improve the estimation of equipment capacities and achievable throughputs. The operation of a mine-to-site ore delivery system is the subject of a number of challenges. Typically, ore is hauled by a given combination of trucks, conveyors and trains. In addition, ore loading, ore transferring to another means of delivery, stockpiling, reclaiming, and further deliveries involve many other types of equipment. The concurrent operation of all these units is scheduled; nevertheless, they are subject to planned maintenance and random breakdowns. To support our engineering design work on ore hauling operation, discrete event type models were built for each specific task. Then, due to recurring demands, an ore hauling library was gradually compiled. The now available model library allows fast and efficient simulation of various mine-to-site hauling arrangement, adaptable to various mining and mine construction operations (e.g. bauxite, iron ore, copper ore and coal).

Aug 1, 2013

By Rachel S. Prudhomme, Michael L. Jeremic

"The consolidation of mine backfill by free zing is a concept which has been under study in the mining engineering laboratories at Laurentian University during the past three years. The proposed underground application of freezing involves the artificial freezing of in-situ backfill by means of a refrigerated brine solution which would be circulated through a circuit off freeze pipes. The most interesting findings to date are: (I) The uniaxial compressive strength off frozen fill is considerably higher than that of cemented fill in a ratio of 20:1 (aggregate to cement), and (2) load deformation characteristics of the frozen fill suggest that a higher ice content results in more brittle failure and that samples which have initially failed can still support up 10 one-half the ultimate load without additional failure.Although at this early stage a derailed economic analysis of the procedure has not been possible, a general evaluation of the costs involved suggests that the method could be competitive with the hydraulic placement of cemented backfill. Results obtained from laboratory investigations indicate that the freezing of backfill is a structurally feasible option .IntroductionGround consolidation by freezing is based on the principle of transformation o f water contained in an aggregate-slurry into ice, which act s as a binding agent between the bulk particles, and which results in the transformation of a granular soil into a ""rock -type"" material. The abrasive nature of the particles enhance s the strength o f the ice by providing internal friction. As a result of this internal friction, the chances of plastic flow of the frozen mass when in a loaded condition are reduced(1). T he strength of a frozen aggregate is al so dependent on the grain shape of the aggregate particles which may or may not promote particle interlocking(2) and on the temperature since, below the freezing point of the water/aggregate mixture, the strength of the frozen mass increase s with decreasing temperatures.In the shaft sinking industry, artificial freezing of loose , unconsolidated soils has been in practice for several decades. Shafts for Saskatchewan 's potash industry have been sun k to depths of 3000 feet by employing artificial freezing to stabilize the Blairmore Formation(3). The common procedure for freezing ground for shaft sinking is summarized as follows(4,5): I) 150 mm diameter bore holes spaced on 1.5 m centres are drilled in a circular pattern with a radius of 1.5 m outside the periphery of the proposed shaft."

Jan 1, 1985

By M. Amsden

"Since the computer program is far from complete this must be only a brief progress report on the computerization of flotation metallurgy at the Ecstall concentrator at Timmins.Ecstall is currently treating about 10,000 tons per day of two different ore types. One is a low sulphide copper-zinc ore, the other is a high sulphide lead-zinc-silver ore. The concentrator is divided into three individual grinding and flotation circuits. In effect there are three mills under one roof. Normally there are two circuits on copper-zinc ore and oneone lead-zinc-silver ore. At this point in time one of the copper-zinc circuits is under computerized metallurgy control.The first step in this control is the use of an ARL on-stream x-ray analyzer, coupled with a Honeywell 21 computer which types out assays and recoveries for each individual circuit. Our approach to a computer program was to keep it simple. The program was written to coincide as closely as possible to what an operator would do in the performance of his duties based on the in-formation he was getting from the x-ray analyser read-out. Initially, computer control was put on just the copper circuit of the ""A"" Division, controlling the collector addition at three points in the circuit; primary, secondary, and scavengers. The control was based on recoveries and the grade of the copper concentrate. Targets like 95% recovery and 24% copper concentrate grades that it was felt the circuit could achieve were set to start with. It quickly became apparent that this alone was not enough because if on a certain ore the best recovery that could be made was only 94.9% the computer kept calling for more reagents until the circuit was completely out of control. On another ore it might have been quite possible to get 96% recovery but when the set point of 95% was reached the computer stopped trying for any more. To overcome this problem a very simple optimum seeking program was devised by one of the Ecstall staff and it has worked very satisfactorily since being put into use in July 1970.In the copper float only the two collectors R-208 and the xanthate R-317 are under computer control. The addition of frother and depressant is left to the operator. The flotation cells have automatic level controls which can be adjusted by the operator. pH is controlled automatically through a lime loop-sensor arrangement."

Jan 1, 1971

By Thomas J. Ferree

"IntroductionThe objective of this chapter is to provide important criteria relating to the operation and maintenance of spiral concentrators and Reichert cones, so that optimum performance can be achieved and maintained in a mill circuit. Little space will be devoted to the theory of the forces of separation or the technical details of the devices, as that in(ormation is available from other sources. The discussions in this chapter will be presented in a manner that should be interesting and useful to anyone who may be exposed to these methods of gravity separation. It is most important for the reader to understand that each application of the equipment should be considered on its own merit, as no two suites of minerals respond exactly alike in mineral processing circuits. The information herein should be useful as a guide toward increasing the metallurgical efficiency of the processes, irrespective of the type of minerals being concentrated.It is highly recommended that certain tools be made available to the personnel responsible for metallurgical performance of the spirals and cones; these include a set of standard type laboratory screens, a medium quality petrographic microscope, and a vanning plaque or gold pan. These devices, when used in conjunction with a basic understanding of the mill circuit, provide immediate knowledge on the characteristics of any sample in the mill circuit. The information gained by visual evaluation of sized fractions of products can solve many of the basic problems of mineral beneficiation, and at the same time increase the interest of the non-technical personnel associated with the plant operation. There are many problems associated with obtaining satisfactory performance from a mill operation. Many of the problems have to be solved using a technical approach. Some of the problems, however, can be solved with practical knowledge and common sense. It is hoped this chapter can provide a guide to both techniques."

Jan 1, 1989

By David Berberick

"Hecla Limited’s No. 4 Shaft at the Lucky Friday Mine is the largest capital expenditure in the corporation’s 128-year history and is considered the deepest shaft in the United States. This paper will discuss the project’s history and lessons learned from the initial conceptual design work in 2007 through project commissioning in 2017. Change management was key for the owner, contractors, and vendors in delivering the operational and organizational success on the project. The No. 4 Shaft has extended the life of the Lucky Friday Mine by 21 years to 2039. INTRODUCTION The Lucky Friday Mine of Hecla Mining Company (Figure 1) is the oldest active (77 years) and deepest mine in the Coeur d’Alene mining district, producing approximately 725 tonnes (800 tons) per day from narrow, vertical, silver, lead, and zinc veins. Primary access into the mine is via the Silver Shaft, a 5.5-m (18-ft) diameter, concrete lined shaft sunk to an original depth of 1,890-m (6,200-ft). Current production is from the Gold Hunter vein system, approximately 1,525-m (5,000-ft) northwest of the Silver Shaft.Cut and fill stoping is currently employed at depths to 2.3 km (7,500 ft) below ground surface, making it one of the deepest mines in the western hemisphere. No. 4 Shaft is a 5.5-metre (18-foot) diameter, concrete lined circular shaft, constructed as a 1.2 km (3,860 feet) deep winze in the Lucky Friday Mine. The 2.4 m (8 ft.) diameter, double drum, double clutch, Siemag hoist and associated headworks are situated at the 4760 level, top station at 4940 and shaft stations at 5900, 6500, 6580, 7500, 7580, 8300, 8380, 8500, and 8620. Shaft stations reference depth below Silver Shaft top station. The 4 Shaft was designed, constructed and commissioned over ten years, between 2007 and 2017. Basic design work was completed by Nordmin Engineering, followed by detailed design completed by Cementation Canada. Shaft construction was awarded to Cementation USA and lateral development was initiated in early 2008. Over the course of the next nine years, the project was suspended and restarted twice, dealt with the loss of a miner, added scope including shaft depth and mine infrastructure facilities, experienced squeezing ground that required liner replacement, changed excavation section, and dealt with a final alignment that was not within design requirement for verticality. Hecla and Cementation were successful in delivering a facility that provides fully functional access from collar at 4940 level to shaft bottom at the 8620 level. Two active mining levels below the collar, 5900 and 6500 are accessed. In addition, the shaft provides access to the future mining level at 7500, skip loading facility at 7580 level, station and loading pocket cutouts at 8300 and 8380 levels, spill pocket at 8500 level, and shaft bottom pumping facility at 8620 level (Figure 2)."

Jan 1, 2019

By G E. Craig, W. M. Williams

A simple, easily constructed apparatus suitable for the zone refining of iron and other reactive materials is described. After eight passes at one inch per hour, the iron produced showed a marked drop in hardness to 49 Brinell. In addition, an arbitrarily -defined recrystallization temperature was lowered by about 35°C and the rate of grain growth greatly increased. CERTAIN materials, of which iron is one, are so reactive that they cannot be zone refined in any known container without becoming contaminated. For such substances, the floating zone method ( 1) may be used. In this method, the specimen is supported vertically in an inert atmosphere and the molten zone supports itself by its own sur-face tension. The method was first applied to silicon (2) and has since been used for other reactive metals such as zirconium and titanium. Smith and Rutherford (3) have previously reported on the floating zone refining of iron; the efficiency of the method for reducing the car-bon content was demonstrated on

Jan 1, 1962

By E. W. Shaw

The past year (1950) has been a big one for the oil industry in Canada, with new records being set in almost every phase of exploration and development activity. New highs were reached in acreage holdings, in geophysical activity, in wildcat drilling, and in field development and production. The only item that did not show a substantial increase over recent years was the amount of reserves added by new discoveries. This was not due to a decrease in the number of new discoveries, however, hut rather to the fact that most of the discoveries were made during the later months in the year and could not be fully evaluated by the year end. The foregoing remarks pertain mainly to activity in Western Canada. In Eastern Canada, operations continued on a modest scale. with exploration drilling down slightly from the previous year but with development drilling and production at about the same level. Returning to Western Canada, it is observed that the general exploration play was one of expansion and intensification. The issuing of new petroleum and natural gas regulations by the province of British Columbia precipitated a moderate entry of companies into the northeastern part of the Province.

Jan 1, 1951

By G. Goodall, M. Muinonen, R. Pandher, R. Jabbar, S. J. Muinonen

"The implementation of a new and highly efficient converting practice at the Glencore Sudbury Integrated Nickel Operations Smelter has opened the possibility to further capacity increases by using larger ladles. To quantify the impact of increasing ladle sizes from 200 to 300 ft3, XPS constructed a detailed discrete event simulation using the commercial software package Rockwell Arena®. The challenges associated with implementing a model on an intricate and tightly scheduled process, and the solutions needed to derive meaningful results will be presented. The aisle capacity is predicted to increase by approximately 17 %, with a reduction in furnace tapping demand of 8 %. Arena modeling capabilities and the key factors contributing to the overall capacity increase at the Sudbury INO Smelter will be reviewed and presented.INTRODUCTION The Glencore Sudbury Integrated Nickel Operations (INO) comprises two Ni-Cu-PGM mines, Strathcona Mill, and the Sudbury Smelter. The Smelter has operated continuously since 1929 using different processes to produce nickel-copper Bessemer matte. Feeds to the Sudbury INO Smelter are a blend of concentrate from Strathcona Mill, Raglan concentrate produced at the mine-mill complex in Raglan, Quebec, as well as third party concentrate feeds shipped to Sudbury from around the world. In 2016, the Sudbury INO Smelter produced 75,900 tonnes of nickel and 20,000 tonnes of copper in Bessemer matte. The product matte is shipped to Glencore’s Nikkelverk refinery in Kristiansand, Norway where it is refined to produce nickel and copper cathode. A schematic of the Sudbury INO Smelter’s flowsheet is shown in Figure 1."

Jan 1, 2017

By Narasimha Mangadoddy, Balraju Vadlakonda

"Bubble size distribution, bubble rise velocity and gas and solids hold-up are the key major hydrodynamic parameters that are extensively used for column flotation design and performance evaluation. The distribution characteristics of mean gas hold-up is studied using electrical resistance tomography (ERT) coupled with pressure transducers (PT) in column flotation. The ERT technique facilitates non-invasive and nonintrusive visualization of different flow regimes even in the presence of particles in a column flotation. The effect of superficial gas velocity, feed flow rate and slurry height in the column on mean gas hold-up and its radial distribution has been analysed for both two-phase and three phase flows. Experimental results show ERT coupled with PT is suitable as an online monitoring tool to provide useful information on the three-phase flow hydrodynamic parameters of the column flotation. The tomography images, which were generated using a modified sensitivity back projection algorithm, are employed to explore the influence of parameters in two phase flow in column flotation. Mean gas and solids hold-up values extracted from ERT have been critically analysed for the column operating in various flow regimes. Gas hold-ups and solid hold-ups results using ERT are in very good agreement with conventional estimation and correlations obtained using pressure transmitter methods. Meanwhile, the results show that the gas hold-ups in the centre region increase constantly with an increase in the superficial gas velocity, whereas solid hold-ups distribution is very heterogeneous for high gas velocity. Furthermore, the results also indicate that ERT is a very powerful tool for diagnosing the 'inside' flow behaviour of gas –liquid–solid three phase flow in columns operating for a wide range of flow regimes.INTRODUCTIONColumn flotation is perhaps the most significant technological innovation in flotation machinery and its successful introduction in mineral processing plants. There has been a lot of attention in understanding the various mechanisms that take place during operation. Due to many reasons column flotation has been found to yield better performance than conventional flotation cells, particularly with fine particles (Honaker & Mohanty, 1996). Due to complex flow behavior in nature, the performance of column flotation influenced by on flow characteristics of the process, (Jena, Biswal, Das, & Reddy, 2008). Previously basic research is carried out to evaluate the effect of the hydrodynamic parameters on performance of column flotation (Finch, J.A.;Dobby, 1991). Many techniques have been developed that could be used to experimentally analyse the hydrodynamics of column flotation. Tomography techniques are well sound to investigate the hydrodynamics for process equipment. Among that, Electrical resistance tomography (ERT) has been used in various industrial investigations for visualization of the concentration profiles and characteristics of the fluid dynamics in gas–liquid two-phase systems (Wang, Dickin, & Mann, 1999; Williams, R.A; Wang, 2000). ERT is an imaging technique to analyse the internal flow behavior non-intrusively. ERT provide very useful tools for measuring and monitoring of column flotation process on line. Due to its high speed capability, low cost measurement, robust sensors, ERT is considered to be the most powerful tool among other tomography techniques such as positron emission tomography (PET), magnetic resonance imaging (MRI), optical and infrared tomography. Application of ERT has extended in process systems due to its improved speed of data acquisition, sensitivity, flexibility and noise immunity. In multiphase flow of bubble columns, gas hold-up and solid hold-up are explored by using the coupling of ERT and difference pressure method (Jin, Han, Yang, & He, 2010)."

Jan 1, 2016

By R. Lapcevic, P. Lokin

"Among other components, ore body „T“ was discovered in the Bor pit copper mine at a depth of app. 500m. The ore body is relatively small: 60-65m long, 40-45m wide and up to 50m high, but with an extremely high content of copper and accompanying metals. The rock mass containing the ore body is composed of altered andesite of relatively poor physical-mechanical characteristics. The exploitation of this ore body by way of conventional mining methods was associated with high risk, cost, and potential losses of the rich ore. Due to everything specified hereinbefore, the adopted solution involved ore exploitation with complete ensuring of excavation stability, thus forming an extremely large underground opening. The excavation and supporting were performed according to the NATM principles along with applying shotcrete, 9-25 m long cables, and horizontal and vertical lattice girders. The excavation of the ore body was completed in app. 2.5 years, all the while ensuring complete stability and security of people and equipment; construction works were constantly monitored. The proposed solution for ore excavation enabled more than 95% exploitation of ore as requested by the Investor, while depletion due to waste-rock excavation was less than the allowed 5%. INTRODUCTIONThe Bor copper deposit is located in Eastern Serbia. Copper exploitation in Bor commenced as far back as 1902. A total of 26 ore bodies varying in size and valuable mineral content have been excavated so far. One of the most recent excavated ore bodies is ore body „T“, which is one of the smallest bodies by volume, but also a body with one of the largest content of copper and accompanying metals. An important fact regarding its exploitation is that it is located at a depth of app. 500 m; that its shape is irregular: 60-65 m long; 40-45 m wide and app. 50 m high; and that it lays within a rock mass of relatively poor physical-mechanical characteristics. In addition, above it, in its immediate vicinity, ore body „F“ was previously excavated and its room was refilled with backfill and water. Excavation methods common in mining practice (excavation with caving, excavation with backfilling, excavation with protective pillars) were inadequate in this case for various reasons:• The immediate vicinity of the previous ore body „F“ room could cause expansion of the caving zone also to that room, along with penetration of groundwater and flotation sludge;• Possibility of deformation expansion caused by caving as far up as the surface of the terrain, including the urban area;• Difficulties in maintaining the stability of excavation sidewalls having steep slopes and great height;• Significant loss of ore mass with a relatively high content of metals etc."

Jan 1, 2015

By Jarret Thomson

An understanding of groundwater flow is essential for many aspects of mining. This is especially true for the process of shaft sinking through the sandstones of the Manitou Falls Group in the Athabasca Basin of northern Saskatchewan. Experience has shown that the hydraulic conductivities of these sandstones can be relatively high, especially in zones containing natural fractures. To develop a better understanding of the inflow potential into a shaft, a laboratory testing program was undertaken to investigate the hydraulic conductivity of fracture core samples from the Manitou Falls Group. This program involved the measurement of hydraulic conductivities under steady-state flow conditions, while cycling the effective confining pressure across a span that is representative of in-situ conditions. The change in fracture aperture was simultaneously recorded at each confining stress level. It was found that existing relationships relating aperture and flow did not accurately capture the behavior of the samples tested. The effects of fracture staining and infilling were also investigated, and were found to have a notable impact on the hydraulic conductivity.

Jun 1, 2012

By T. Donkin, B. Patterson, M. I. Guthrie, J. T. Ross

"The interest in the use of sensor-based particle ore sorting has increased significantly with the recent advances in the sorting technologies and higher capacities per unit. This technology has the potential to provide great value in processing lower grade ores from the mine whilst delivering higher grades to the mill as well as in upgrading waste rock into ore. Typically, the focus is on the amenability of the ore to ore-sorting and associated reductions in the consumption of energy, water and consumables. However, layout has a significant impact on the installed cost of a concentrator and the layout impacts from fitting an ore-sorting circuit into the concentrator plan need to be carefully considered. This paper examines layout considerations that play an important role in ore sorting projects. These include additional crushing and screening requirement, transportation of the rejected material back to the waste stockpile (mine fleet requirements) and effects on concentrator footprints.INRODUCTION Ore sorting has been practiced throughout history with an early report by Agricola in 1556. Metallic and non-metallic minerals were extracted from rocks by laboriously breaking them with hammers and picks and hand-picking selected material with higher grade off a table. The concept has not changed but the sorting technology has evolved significantly over the last 20 years. Ore sorting is usually a dry process in which a portion of the material is rejected based on mineral properties and/or grade. The methods used for sensing ore particles cover a large range of physical properties. A variety of sensors are available that differ on the discrimination technique that is used, which include: photometry, radiometry, conductivity, magnetism, microwave, X-ray transparency: X-ray transparency and luminescence and UV fluorescence (Sivamohan and Forssberg, 1991; Wotruba, 2006). There are two main ore sorting techniques: particle ore sorting and bulk ore sorting. According to Nadolski et al (2018), the potential for sorting is determined though analysis of grade heterogeneity within the orebody (greater heterogeneity represents more opportunity to add value to a project) at the scale of the intended sorting unit size."

Jan 1, 2019