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By A. Shakoor, T. P. Gautam

The long-term slaking behavior of clay-bearing rocks in the field can be quite different than the short-term slaking behavior in the laboratory. To assess this difference, 12 replicate samples of each of 20 clay-bearing rocks, including 5 claystones, 5 mudstones, 5 siltstones, and 5 shales, were exposed to natural climatic conditions for 12 months. After each month of exposure, one replicate sample of each rock was removed from natural exposure and its grain size distribution was determined. Disintegration ratio (DR), defined as the ratio of the area under the grain size distribution curve of the slaked material for a given rock to the total area encompassing all grain size distribution curves of the tested samples, was used to quantify the amount of disintegration under natural climatic conditions. DR values of naturally exposed samples were then compared with the corresponding values of second-cycle slake durability index (Id2) determined in the laboratory. The relationship between Id2 and DR after, 1 month of exposure, exhibits an R2 value of 0.65 but the relationship deteriorates when DR values for 6 and 12 months of exposure are used, with R2 values of 0.63 and 0.25, respectively. However, when DR values for laboratory samples, computed from grain size distributions of slaked material after second cycle, are compared with DR values of naturally exposed samples for the three periods of exposure, the relationship improves with the corresponding R2 values being 0.61, 0.71, and 0.41. These results suggest that DR may be a better parameter for assessing the long-term disintegration behavior of clay-bearing rocks than Id2.

Jan 1, 2015

By Namavari. H., M. Ashouri, M. R. Sarhadi, S. H. Mansouri, A. Sarrafi

The splash phenomenon and its effective parameters in metallurgical converters have been studied thoroughly for decades. The detailed studies of processes such as tuyere blockage, wave formation during air injection, entrapped phases, and also processes which control the formation of bubbles in viscous fluids are not feasible yet. In this research, we have used a converter-shaped vessel made of flexi-glass. Water and oil have been used as matte and slag phases respectively. The effective operational factors responsible for creation of splashing have been studied such as air flow rate, tuyere angles, depth of tuyere submergence, tuyere blockage, density and viscosity of liquids, liquids heights, etc. The results have been found as follows: the amount of splashing increases slowly as air flow rate increases. However, as the air flow rate reaches a critical value (depending on the physical specification of converter) the amount of splashing rises sharply, because the flow of air inside the liquid changes from bubbling into a jet stream; and most of the splashed materials are in the form of filaments instead of droplets. Changing tuyere angle from horizontal towards vertical position will increase the turbulence level on the fluid surface and causes an increase in the amount of splashing. The effect of tuyere submergence is related to the converter opening angle. As the converter opening angle is shifted towards the hood position, the amount of tuyere submergence and splashing will increase. As density of the liquid increases, the number of droplets splashing increases with a decrease in drop size. Therefore, the total amount of splashing decreases. However, as viscosity of the liquid increases, the splashing material increases due to the changes in the splashed material from droplet shape into filament form. The height of liquid inside the converter, depending on the relative height of heavy phase and light phase, is an important parameter regarding splashing. As the relative height of heavy phase to light phase increases the splashing will decrease. The tuyere blockage will cause the pressure in the inlet manifold to increase; and in real cases will increase the splashing. Finally, we have development a model based on dimensional analysis to relate the above parameters in order to calculate the amount of splashed material.

Jan 1, 2007

By W. W. Bake

INTRODUCTION IN IN JUNE, 1943, the main pillars of the Beattie Mine glory hole failed, allowing over a million yards of wet clay and debris to flow into the mine, completely filling all workings to within seventy feet of the 3rd level. The resulting Job of clearing these workings and rehabilitating the mine represents a unique and hazardous operation, seldom, if ever, previously encountered in Canadian mining. The purpose of this paper is to describe one phase of this operation -that of cleaning and rehabilitating the mine from the 6th to the 9th level -to outline briefly the events which led up to this work and to describe the techniques and costs involved. It will be noted that such costs, methods, and performance figures as are dealt with in this paper refer only to work in the internal shaft and adjoining workings from the 6th to the 9th level, previous work having been done under other supervision and management. The Beattie mine is in Duparquet township, northwestern Quebec, twenty miles northwest of the town of Noranda and twenty-three miles southeast of the town of La Sarre. The mine and the town of Duparquet, which it?supports, are accessible by highway from Noranda throughout the year. Production at the Beattie mine began in May, 1933, and up to June, 1943, twenty-one million dollars in gold and silver had been recovered from five and a half million tons of ore.

Jan 1, 1951

By Joanna LaForte

"IntroductionIn respect to The Human Dimension by M. Phyllis Bray, this author's impression is that research on long distance commuting (LDC) is long overdue. This type of mining is not new to many workers, especially those from areas such as the Maritimes, who have had to look for work away from their families for at least a decade. Perhaps to the industry the over-all set-up is new, but to workers who have faced mine shut-downs in their areas finding a job was the main objective and if the security of long-term employment was evident, then the families might join them later. This was the situation with which the writer' s family was faced.LDC LifestyleBeing the wife of an underground miner, the author has personally experienced this lifestyle for almost 10 years, and has never experienced accommodation in a company town. The first five years of marriage were spent in a small rural municipality within 50 miles of the worksite, but the town had industry separate from mining and was not affected by the mine shut-down.Since her LDC lifestyle began her family has been pretty much city-based, out-of-province commuters with two children and a third to arrive some years later. She therefore lived a fairly normal married life with a husband home daily. The author has experienced life with a husband who worked away for five-day stretches and then drove long distances to be home weekends or the portion of time left over from driving and fatigue. She has done the 3D-days in/l4-days out routine, and for approximately the past four years has been existing on a two-weeks in/two-weeks out ritual .The author does not agree that the ""bottom line is that mining families go where the jobs are"" . The miners go where the jobs are and the families fend for themselves with the assistance of the pay cheque making it home each pay period.Perhaps because there are many personal frustrations with this type of lifestyle, perceptions may be inaccurate. Having only dealt with underground operations, there may be gross differences between the pressures and demands of other forms of mining."

Jan 1, 1991

By M. Moats, J. A. Gonzalez

A review of operating practices in zinc electrowinning plants is presented in this paper. Surveys were sent to several zinc electrowinning plants and data provided by some of these plants was compiled in a database. Information about anodes and cathodes, electrolyte composition, stripping methods, cells, electrical systems, and additives was compiled and analyzed. From the data analysis, correlations between operating variables are presented. Recent trends in operational practices are also highlighted.

Jan 1, 2008

By N. Valkanov

This paper presents results of an investigation into the connection between minerals liberation management and flotation, responding to lead-zinc concentrator ?Erma reka?, in Bulgaria. Monitoring of a Zn flotation circuit was carried out. The causes for the high silica content in the final Zn concentrate were established. Quartz is present mainly as liberated particles (> 60?80 %) in the fine fractions of the products; therefore the selectivity of the flotation process is not effective. Two approaches were tested to reduce the quartz content of Zn concentrate: froth washing in Zn cleaner flotation and new gangue depressants in the Zn circuit. Experimental results from bench-scale flotation and industrial tests show that it is possibile to reduce the silica content of final Zn concentrate more than 2 times without the need for extensive regrinding. The depression of liberated quartz particles on all operations of Zn circuit using stage depressant addition is the right solution to produce high-grade Zn concentrate that meets the metallurgical requirements.

Aug 1, 2013

By J. J. Denny

The purpose of this paper is to present, briefly, an outline of Canadian practice in the milling of gold-bearing ores- not, however, including those auriferous ores which are mined and milled primarily for their content of some other metal. It is not the writer's intention to offer technical data, nor to discuss any particular phase of the metallurgy, but rather to give a general résumé of past and present methods. As it is only within recent years that gold milling has assumed prominence in Canada, much of the technology is modern, and detailed articles describing the practice adopted in the several mining districts, and recording the various changes and innovations that have been made from time to time, are to be found in the Transactions of the Canadian Institute of Mining and Metallurgy, and in the mining journals. Prior to the year 1860, any gold that had been produced in Canada had come from placer operations in British Columbia, but ' during that year lode gold was discovered in Nova Scotia, in quartz veins, and in several localities mines were opened and small mills of very simple character were erected to treat the ore. These plants, equipped with stamps, or arrastre, were only effective in recovering the free gold. Concentration and chlorination were introduced in an endeavour to save the gold occurring in intimate association with metallic minerals, but, due to various circumstances, gold mining and milling did not progress in Nova Scotia.

Jan 1, 1930

By E. You

The concentrator at Kennecott Utah Copper currently has 4 lines with a configuration of one SAG mill feeding two ball mills. The slurry that reports to each ball mill will vary resulting in an unequal load of material. This configuration contains two separate sumps that receive material from a distribution box relying solely on natural slurry flow to feed each sump. The unequal split to each mill results in one mill receiving a greater amount of material. This will result in the equipment on one mill reaching limitations that may affect product quality and the operation of the equipment near maximum. The parallel mill in this condition will often have additional capacity that can be used but cannot be utilized due to the unequal split. The major consequences of this issue result in reduced throughputs and metal recovery. To resolve this condition an advanced control strategy was implemented to control the split in April of 2002 using equipment that was in place.

Jan 1, 2007

By T. W. Wlodek, Zygmunt Kowalczyk

In the period from 1946 to 1964, the annual output of co al from Polish mines increased from 4 7.3 to 117.35 million tons. In this paper, the methods of bringing about this increase in productivity through the building of some twelve new collieries (producing some 15 million tons annually) and the modernization, reconstruction and extension of some thirty-six older collieries are discussed.

Jan 1, 1967

By J. Stachulak

In recent years more emphasis has been placed on the control of nitrogen dioxide (NO2) emissions from mining diesel equipment. Worldwide, diesel engine regulations to control emission and protect the environment are also driving the development of the diesel engine technology to reduce oxides of nitrogen NOx (Nitric oxide, NO + NO2). NOx are toxic gases produced in mines during the operation of diesel equipment. Most of the diesel equipment used in underground operations are equipped with Diesel Oxidization Catalysts (DOCs) designed to reduce carbon monoxide (CO) and hydrocarbons (HC). The effects of DOCs on NO2 production from diesel powered equipment is not well understood. DOCs do not alter NOx concentration, but may promote the oxidization of engine exhaust NO to the more toxic NO2, thus increasing the undesirable NO2 exposure of workers in the mine environment. In 2012, the ACGIH reduced the NO2 TLV concentration value from 3 ppm to 0.2 ppm. Vale and CanmetMINING have been involved in several research projects to reduce diesel emissions exposure to workers. One aspect of the current program is to determine the effects of in-use DOCs on NO2 production. Several in-use DOCs taken from mining equipment were selected for testing in the laboratory using ISO 8178-C1 and mine LHD transient test cycles. The paper presents the laboratory test results and effects of DOCs on NO2 production. The results indicate significant reductions in CO concentration, by over 77%, while increases in NO2 varied from 46% to 315% based on the ISO 8178-C1 8-mode steady state test cycle. The mine LHD transient test cycle showed the same pattern, although the magnitude of CO reduction was less. Consequently, it is recommended the use of only those DOCs that have been properly evaluated and shown not to significantly increase NO2 emission in the environment be used on mine equipment.

Aug 1, 2013

By J. Kang

There is increasing demand to utilize aluminium alloy sheets and their spot welds by the automotive industry. While traditional uniaxial tensile tests only determine mechanical properties to small strain, direct measurement of the constitutive behaviour of aluminium alloy spot welds at large strain remains a challenge. A technique was successfully developed using digital image correlation coupled with shear tests to directly measure the constitutive behaviour of an AA6022-T4 spot weld to large strains. The results show that the spot welding process not only decreases the yield strength but also lowers the work hardening rate of the nugget versus the base material. Details of sample preparation, experimental approach and results will be discussed.

Jan 1, 2011

By K D. Conroy

For the past year, Lowphos Ore Ltd. has been operating two desliming hydroseparators on a fully automatic basis. Automatic operation is achieved by sensing the position of the silica-magnetite interface and automatically controlling the jet water addition to maintain a desired interface position. The system further provides automatic control of the underflow pump speed in order to assist in maintaining interface position when an <Ore change occurs. Interface position is maintained at 12 inches below the surface and is -controlled within plus or minus one inch. Metallurgical unit recovery is held above 98.5 per cent, and a 10 to 12 per cent increase in concentrate grade is normally achieved.

Jan 1, 1963

By S. Bhattacharjee

"Rock failure process is generally recorded or measured using conventional sensors like strain gauges, seismic, micro-seismic, acoustic, electromagnetic and other techniques. The above sensors are either to be pasted on the surface of the rock sample or placed very near to it to capture the response of the sample with the increment of load. This requires precise tools to cut or polish the locations where sensors are to be placed. Moreover, deformation or acoustic or micro-seismic activities are recorded only at the locations where sensors are pasted.Recent development in Digital Image Correlation (DIC) technique has shown promise to measure deformation / strain at every location of the surface of a sample. In DIC, two images (reference and deformed) are taken within a small time interval of the same object are compared to estimate the change in reflectance as a function of displacement, velocity or rate of strain at each pixel while the object is undergoing through a loading process. In this study, extended digital image correlation (X-DIC) technique has been implemented using 4-noded quadrilateral elements with a discontinuity surface in the deformed image. The continuous and enriched displacements are estimated at each node.The X-DIC method is verified using numerically generated images. The study has been further extended to evaluate the performance of X-DIC method on deformation analysis of experimental samples under uni-axial loading condition. The results of this study show that X-DIC method is an effective tool for determination of displacements of the entire surface of a rock sample having a discrete crack or discontinuity in a non-contact manner. This method demonstrates the applicability to investigate rock failure mechanism for the entire sample in a laboratory set up as well as monitoring of pillar failure mechanism in underground mines."

Jan 1, 2015

By John Hughes

1. De Beers, Diamonds and Canada 1.1. De Beers was founded long ago (1888, the same time that Canada became a country) in a rural mining village in South Africa. Today, we employ 22,000 people across 19 countries and have 14 mines including open pits, shafts, beach-sands and seabed. 1.2. Last year our sales were US$5.7 billion and our total production amounted to 47 million carats which means a 40% global market share. For the Kyoto buffs in the audience, the company consumes 66 million cubic metres of water per annum, 210 million litres of hydrocarbon fuel and 1,600 GWh of electricity. Stats are good, but aren?t as expressive as a movie. This one is 2 minutes long, which is quicker than I could elaborate. (Video 1 - 2 minutes) 2. De Beers in Botswana is the leading source of diamonds 2.1 Today Botswana is the Jewell in the Crown. There are three big open pits that enjoy economies of scale that make them the lowest cost producers. Last year 60 million tonnes of overburden and 30 million tonnes of ore were moved in Botswana alone. Botswana produced 31 million carats, compared to 14 million carats in South Africa and 2 million very high quality carats inn Namibia. 3. Diamond Mines provide feedstock? ?.to jewellery stores

Apr 1, 2005

By M. M. C. Lima, L. C. S. Solimani, M. A. Quintela

Galvanized steel scrap is recycled to B OF converters where zinc escapes from the bath and is captured by the gas control system, appearing in BOF sludge. As BOF sludge contain high iron content, it could be recycled, but due to its zinc content, it is disposed in landfills. In this study techniques were evaluated for zinc layer removal from scrap by sulfuric acid leaching. The effects of coating weight, temperature, time and sulfuric acid concentration were evaluated for three different galvanized scrap. The results showed that the behavior of each galvanized scrap was different. Nevertheless zinc removal efficiency was more than 80% with low dissolved iron in the leached solution.

Jan 1, 2011

By A. Ignatieff

"Excavation, the principal mining process, 'which hitherto has been based largely on the intuition and logic of mining men, is increasingly receiving the attention of engineers and scientists versed in rock mechanics. The paper intro-duce the principles of this science in simplified form, directed both to underground and open-pit mining. Reference is made to the large annual tonnage from ore and rock excavations, which in 1967 were responsible for 250 million tons of mineral production in Canada.The urge to transform excavation into a continuous instead of an interrupted process is discussed with references to the various types of energies employed or proposed in rock breakage or excavation. Due to the rapid decay of applied energy in the discontinuous and heterogeneous rock environment, large confined blasts proposed for in-situ mining do not give much expectation of success as yet. Raises and ventilating shafts are already bored in reasonably hard rock. Tunnelling machines will be used for drifting and cross-cutting in the future, but continuous mining machines of the cuttmg and shearing type are not 'around the corner' for stoping typical orebodies. On the other hand, bed mining, particularly of coal, has led the way in continuous mining, and Remotely Operated Long-wall Face (ROLF) experiments are progressing in an encouraging way. Some reflections on the mining environment in relation to the human element are made."

Jan 1, 1970

By Z. Huda

The effect of various percentages of cold-working and recrystallization on the microstructure and hardness of commercially-pure aluminum plate, has been studied. The &apos;A critical deformation for the aluminum, has been determined. Experimentation involved cold rolling and recrystallization processes followed by quantitative metallographic practice and the hardness measurements. The raw material chosen was a plate of commercial aluminum which was cold rolled to different percentage of cold-work and then recrystallized by heat treatment at 150°C. The critical deformation percentage of aluminum was computed to be around 30% of cold-worked.

Jan 1, 2007

By Z. Luo, China University of Mining & Technology, C. Duan

"The magnetic separation removal rate of pyrite could be improved effectively by increasing the susceptibility of pyrite. The electromagnetic characteristics and absorption response performance of high-sulfur fine coal were studied in strengthening the susceptibility of pyrite. In the process of treating the sample through the microwave, electromagnetic energy could be converted into heat energy due to dielectric loss and magnetic loss. The RL(dB) was evaluate the performance of absorption response of coal. The microwave improved the susceptibility was in ultra-high frequency region, which is the most natural resonance. The absorption fine coal to microwave was strengthened and microwave energy was improved by adding the magnetite powder with double loss characteristics as the microwave absorber. The dielectric properties and permeability characteristics of the fine coal trend were investigated by maxing magnetite powder. The microwave absorption in different coal thickness was surveyed through the reflection of energy loss.INTRODUCTIONMicrowave desulfurization is one of the most important research directions (Haque, 1999; Makul, Rattanadecho, & Agrawal, 2014; Su, Tang, Zhang, Jing, & Bai, 2014). The working principle of microwave absorption response can be briefly described as the interaction of the sample with microwave energy, which will result in the microwave energy converting into heat energy loss (Keangin & Rattanadecho, 2013). For specific samples, the polarization effect includes multiple polarization mechanisms(Meikap, Purohit, & Mahadevan, 2005). Different polarization mechanisms have different occurrence time and dominant mechanisms. Meantime, energy consumption will be occurred during the process of polarization effect (Chelgani & Jorjani, 2011; Rowson & Rice, 1990) . The absorption of microwave energy in the fine coal is a process of electromagnetic response (Znamenácková, Lovás, Mockovciaková, Jakabský, & Briancin, 2005). Microwave transfers the electromagnetic waves into the heat energy by microwave dielectric loss and magnetic loss for achieving the absorption of microwave energy in the treatment of samples (Lee, Kim, Kim, Chung, & Kim, 2004). The additive magnetic medium is Fe3O4 belonging to microwave energy absorber of double loss medium (Uslu, Atalay, & Arol, 2003)."

Jan 1, 2016

By V. W. Shtenko, B. J. Ennis, P. H. Bridge

"The northeastern region of British Columbia contains large quantities of high-quality metallurgical coal. To market the coal, it was necessary to provide the required infrastructure which included rail access. This paper presents the role of the British Columbia Railway in the northeast coal development.In 1976, B.C. Railway undertook to study two main routes, one originating at Chetwynd and the other at Anzac, both located on the main line, north of Prince George. The routes studied are briefly described, detailing the methodology and engineering analysis carried out to permit the selection of a single route that would be the most cost effective, taking into consideration the construction, maintenance and operating costs. The operating parameters, track and grade standards, anticipated tonnage, construction costs and the final route selected are also presented.Pre-engineering analysis and studies of the route selected originating at Anzac, known as Tumbler Ridge Branch Line, and which commenced in 1977, were concluded in 1978. New mapping was developed to a scale of 1:2000 with good vertical and horizontal control. Based on the mapping data, terrain analysis, and designs developed, an estimate of construction costs and schedule of work was developed.Authority to proceed with the final design and construction was provided in December 1980, with the first shipment scheduled for December I, 1983. Final designs of all structures are discussed, including schedules, cost to completion, and control systems utilized. The decision to electrify the Tumbler Ridge Branch Line and related topics are discussed, with a brief description of train operations. The present status of the project is also presented."

Jan 1, 1983

By R. P. van Hille, N. Mooruth

Remediation of acid rock drainage (ARD) was performed within a linear flow channel reactor (LFCR) via a floating sulphur biofilm (FSB). A full sulphur species material balance was conducted in order to characterize the sulphide oxidation. The reactor was able to achieve an 82% and 93% conversion of sulphide with a hydraulic residence time of 2 and 5 days respectively. 92% and 55.5% of the converted sulphide reported to the biofilm as sulphur for the 2 and 5 day residence times respectively. The mass transport limitations within the biofilm were identified via a dissolved oxygen gradient profiling system.

Jan 1, 2011