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By A Hitchen

A general outline is given for the determination of copper, nickel, cobalt, zinc, lead, cadmium, bismuth, manganese, uranium, molybdenum, vanadium, sulphate and fluoride by polarographic or amperometric methods in a variety of ores or metallurgical products. The detection of oxygen in gas mixtures by an amperometric method used as a safety device is also discussed. Introduction I N this paper, a general outline will be given of the polarographic and amperometric methods used for the chemical analysis of various ores and metallurgical products in the Chemical Analysis Section of the Extraction Metallurgy Division of the Mines Branch. The methods to be discussed will be confined to those based on the use of normal D.C. polarography and will not include those methods which utilize a cathode-ray, square wave, pulse or A.C. type of polarograph. For the sake of convenience, ? the polarographic methods will be discussed according to the type of supporting electrolyte employed, as the same electrolyte may serve to determine more than one element in more than one type of ore. Amperometric methods will be discussed according to the element to be determined rather than

Jan 1, 1965

By Min-Yuan Cheng

Heavy rainfall and typhoon oftentimes cause the collapse of hillslopes across mountain roads. Disastrous consequences of slope collapses necessitate the approach for predicting their occurrences. In practice, slope collapse prediction can be formulated as a deterministic classification problem with two class labels, namely ?collapse? and ?non-collapse?. Nevertheless, due to the criticality and the uncertainty of the problem, evaluating the collapse susceptibility of an area is a challenging task. This study proposes a novel Artificial Intelligence (AI) approach, named as K-Nearest Neighbor Based Bayesian Classifier (KNNBC), to deal with slope collapse assessment. In the proposed model, Bayesian inference is used as a framework to achieve probabilistic prediction of slope collapse. Meanwhile, K-Nearest Neighbor (K-NN) is employed as a density estimation technique. Equipped with probabilistic outputs, the K-NNBC is able to yield predictions with different levels of confidence and diminish misclassified cases. Experimental results point out that the proposed model is very helpful for decision-makers in slope collapse assessment and disaster prevention planning.

Aug 1, 2013

By Grant Small, Jessica Kinal, Christopher J. Greet

"The conversion from an electrochemically reactive grinding media (forged steel) to a more electrochemically inert alloy (high chrome white iron) not only reduces the wear rate of the grinding media, but also has an impact on the grinding chemistry. Typically the grinding chemistry becomes more oxidising, with less reducing Eh values and more dissolved oxygen in the pulp. There is also a decrease in the EDTA extractable iron, which is an indication of the change in the media corrosion. These changes are indicative of alterations in the surface chemistry of the minerals that the operator is trying to separate. For porphyry copper ores the changes in the pulp and surface chemistry not only affect the copper sulphide minerals, but also impact the iron sulphides (i.e. pyrite and pyrrhotite). Generally, with more oxidising pulp chemical conditions during grinding there is an increase in the oxidation of the iron sulphides which renders their surfaces hydrophilic, thereby depressing flotation. This leads to improved selectivity for copper sulphides against iron sulphides.INTRODUCTIONPorphyry copper deposits are the dominant source of copper that is mined today to satisfy global demand. These style of deposits typically contain one percent copper mostly as chalcopyrite, but may contain other copper bearing minerals (for example, bornite, chalcocite, azurite, malachite), small quantities of pyrite and quartz. Porphyry copper deposits also contain economically significant quantities of gold, silver and molybdenum. Interestingly, the majority of the world’s porphyry copper deposits are concentrated along tectonic plate boundaries (Figure 1)."

Jan 1, 2016

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 Nick Vayenas, Ming Cai, Hongbin Zhang Lorrie Fava, Enrique Acuña

"A hybrid methodology is proposed to improve the accuracy of Diesel Particulate Matter (DPM) concentrations simulated in a ventilation network model by using Computational Fluid Dynamics (CFD). DPM, as a primary concern for underground hard-rock mines, has been studied in two dominant numerical models, ventilation network solvers and computational fluid dynamics. Ventilation network solvers are efficient, but they are not able to provide three-dimensional DPM concentration contours and only accept area-average DPM data as input. CFD simulations are time-consuming, but generating DPM concentration results with high accuracy. Besides, both monitoring points and planes can be created in a CFD model, which can take both point data and area-average DPM data as input. The hybrid methodology is intended to combine the advantages of the two by using the CFD results to update the network model results at key locations. A field study was conducted in a dead-end heading in an underground gold mine in the United States. Real-time DPM monitors were used to collect data. A CFD model and a network model were built for the experiment area. The CFD model was calibrated to the experimental data. In the study presented here, results from a calibrated CFD model are converted to equivalent diesel emission rates in the ventilation network model at a shared outlet. The hybrid methodology is used to provide better input for the network model. INTRODUCTION Mine ventilation system is one of the most important parts for an underground mine. It not only provides fresh air to the personnel but also helps clear the contaminants generated from the diesel-powered equipment. For most underground metal and non-metal mines, diesel particulate matter is the main contaminant. It is also the focus of this paper."

Jan 1, 2019

By Ausenco Engineering Canada

"This paper demonstrates the selection of grinding circuit technology for a number of recent projects including discussion of the key drivers and the role of energy efficiency. Decreasing head grades combined with a strong and sustained increase in operating costs has forced miners to examine increased project size, increased equipment capacity and efficiency improvements in order to reduce their unit operating costs and improve overall project economics. Comminution energy consumption, safety and capital cost considerations play a critical role in the success of projects. This paper presents some key guidelines for a successful and cost effective comminution circuit design and includes a case study on three projects, outlining the issues and the drivers which led to the ultimate circuit selection and the critical role that energy efficiency played.INTRODUCTIONComminution circuits for minerals processing are selected based on their suitability and efficiency in reducing run-of-mine ore to the desired feed size for the downstream process. The input material (ore) properties and downstream process requirements are the key determinants and there are standard approaches for each circumstance.The minerals processing industry has been a fast adaptor of efficiency improvements based on increasing capacity of equipment (e.g. trucks, crushers, mills, pumps) but less successful in adapting radically new technologies that disrupt incumbent flowsheets or processes.The installed power of grinding mills has increased linearly over the past 25 years (Meka & Lane, 2010) and pumps and classification equipment have kept pace. The autogenous grinding (AG) and semiautogenous grinding (SAG) mills displaced stage crushing as a dominant method of coarse rock breakage in many applications causing crusher manufactures to increase the capacity of cone crushers to meet the competitive demand.Examples of new comminution technology in the 20th and 21st centuries are the development and adoption of cyclone classification in the 1940s (Newtech, 2016), AG milling in the late 1950s, vertical grinding mills in the 1980s, high pressure grinding rolls (HPGRs) also in the 1980s and ultrafine milling technology in the 1990s (Meka & Lane, 2010)."

Jan 1, 2016

By J. A. Herbst

Professor Klaus Schönert and his students used fundamental physics to develop many of the principles required for the design and scale-up of "Gutt Bett Zerkleinern" devices such as the high pressure grinding roll (HPGR) or the high pressure roll crusher (HPRC). As the equipment evolved so have the tools used for its selection and analysis. In the current paper discrete element modeling (DEM), Metso&apos;s proprietary Fast Breakage simulations, and Schönert&apos;s packed bed piston test are combined with energy based population balance models (PBM) to yield an alternative to ore characterization and equipment selection by pilot plant testing. The resulting methodology is used to take the next step in understanding these devices with a view toward predicting plant performance. This paper describes a journey beginning with precise modeling of a small HPGR including stud geometry and system hydraulics. A key to predicting performance is the accurate modeling of individual particles, their motion in the machine, the probability of breakage and redistribution of fragments, and the inter-particle breakage events that occur between the rolls at different pressures, speeds and moisture levels. Advanced DEM simulations and particle breakage characterization methods provide the necessary technology. The resulting combined models were validated using a small diameter laboratory scale unit. The validated physics based model was used then used to predict the performance of plant scale units using a specific energy based scale-up method. Scale-up results are analyzed in terms of power draw, throughput, and discharge product size distribution.

Jan 1, 2012

By N. Gharib, F. Hassani, P. Nekoovaght

"Novel rock breakage techniques are becoming more viable and attractive to industry. Microwave energy, as a thermal energy capable of inducing micro cracks through differential heating (therefore expansion) is a technology gaining considerable attention in mineral processing and ore comminution applications. Recently, the use of microwave radiation has been evaluated as a possible avenue for terrestrial and extra-terrestrial drilling applications as well as full face tunneling or rock breaking machines. As part of an overall research on use of microwave in rock breaking systems, the influence of microwave energy on the mechanical properties of common hard rock types as basalt has been investigated. The results revealed that microwave energy irradiation imposes micro and macro cracks to the surface of the rock being irradiated. In explosive free tunneling applications using TBM, jointed and cracked surface of rock eases the cutting process and increases penetration rate. The experimental setups have been simulated with the help of a multi-physics numerical modeling and the results have been compared with practical experiment. The wave propagation of microwave has been simulated and the distances where the power intensity is higher are identified. Experimental and simulation results underlined the potential impact of the use of microwave energy in underground or surface excavation applications such as mining and tunneling. This will also contribute economically when mine-to-mill operation is fully considered to improve the efficiency of rock crusher stages. INTRODUCTIONDuring hard rock breakage (i.e., separation of a piece of a rock from its parent deposit) in mining and civil applications, the performance of mechanical equipment such as tunnel boring machines (TBMs) is limited by high levels of bit wear and maintenance. Preweakening natural rock prior to breaking it by machine is one approach to lower bit wear and maintenance costs. Some preweakening methods apply heat directly or indirectly. For example, flame torch-assisted TBMs (Lauriello et al., 1974; Resource Technology, 1984) have been deemed economical in terms of equipment, but their feasibility is limited by high fuel consumption. Microwave energy could offer several advantages over the flame torch method: it does not produce emissions or increase fuel consumption (electricity source is available on the machine), and is easy to control (quick power on and off)."

Jan 1, 2015

By J. F. Wright

During the last three years prospecting has been active in southeastern Manitoba and a number of interesting gold, nickel and copper deposits have been discovered within an area 90 miles north of the international boundary, and extending about 40 miles westerly from between mileage 60 and 110 on the Manitoba-Ontario boundary. As known at present, two-thirds of this area of 2,000 square miles is underlain by pre Cambrian granite and granite gneiss and is not likely to contain mineral deposits of economic importance. The remaining one-third is underlain by metamorphosed sediments and lavas (greenstones), penetrated by the granite and granite gneiss and, at various localities, cut by bosses, sills, or dykes of gabbro, diorite, granodiorite, and other types of intrusives. The nickel, copper, and gold mineralization accompanied or followed the intrusion of these different rock types. The gold deposits are limited in distribution, so far as known, to the northern part of this prospecting area and occur along Manigotagan and Wanipigow rivers. These deposits have recently been described in some detail, (3) and therefore only the copper and copper-nickel deposits of the southern part of this area, along Oiseau and Maskwa rivers, will be described in this paper.

Jan 1, 1925

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 K. Harris, J. B. Wahl

Ni-base superalloy cast materials provide an outstanding balance of high temperature strength, fatigue resistance, oxidation resistance and coating performance and can be produced to very tight tolerances in extremely complex configurations, such as axial and centrifugal integral cast turbine wheels. As a result, cast superalloys are used in the most demanding applications of aero and industrial gas turbine engines. Use of these materials is expanding to smaller microturbine, turbojet, turbocharger and missile engine applications due to this unique combination of desirable properties. This paper will present an overview of the application of investment cast Ni-base superalloys and process capability to small turbine and missile engines.

Jan 1, 2010

By M. E. Bilir

In this paper, we review cases in which dramatic and visual swelling problems are experienced in underground structures. Swelling rocks have caused many problems in underground engineering projects. They pose severe problems to the design, construction and maintenance of underground openings. If an appropriate integrated design procedure, which proceeds from exploration, tests, analyses and realistic assumptions of swelling behavior, is used during the design stage, the execution of the project can be completed without any serious delays or dramatic design changes. The case histories were subdivided into three classes that include tunnels, underground coal mines and others. For the evaluation of cases, the surrounding rocks, swelling minerals, water inflow, swelling test results and swelling problems were considered. The main purpose of this review is to inform the reader about potential problems with swelling phenomenon and to emphasize the rehabilitation and extensive cost which are encountered due to the lack of necessary integrated design approaches.

Aug 1, 2013

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 M. Imani, A. Fahimifar, A. H. Javid

"Current studies of bearing capacity for shallow foundations tend to rely on the hypothesis of an isolated footing. In practice a footing is never isolated; it is mostly in interaction with other footings. This paper focuses on a numerical study to evaluate the ultimate bearing capacity for two interfering strip footings resting on a rock mass in which the strength can be described by the generalised Hoek–Brown failure criterion. This criterion is applicable to intact rock or heavily jointed rock masses that can be considered homogeneous and isotropic.The material is assumed to exhibit perfect plasticity and obeys an associated flow rule. The effects of Hoek–Brown parameters including GSI, mi, and sci were studied and the corresponding results are presented. For different clear spacing (S) between the footings, values of the efficiency factor (?) were determined; where ? is defined as the ratio of the failure load for an interfering new footing of a given width (B) to that of a single isolated footing having the same width. The maximum value of (?) occurs at spaced between S/B = 0.5 to 1.0. The results have been compared with those available in the literature.INTRODUCTIONEvaluating the ultimate bearing capacity of rock masses is essential for important projects like dams and bridges. Closely spaced footings may occur on rock masses in the form of pier foundation and grillage footing. Close spacing lead to permit higher loads than can be bore by similar isolated footings. The ultimate bearing capacity of two interfering strip footings resting on cohesionless soil have been studied theoretically (Kumar, & Gosh, 2007; Kumar, & Kouzer, 2008; Stuart, 1962). Results revealed when two strip footings approached closely enough, failure zones affect each other and ultimate bearing capacity significantly increased."

Jan 1, 2015

By G. Fuentes, J. Viñals

"The nature and basic kinetics of the hydrothermal reactions of bornite, covellite pyrite and enargite with copper sulfate solutions were investigated, as a previous study on the behavior of the bulk Chilean copper concentrates. The reaction of bornite produced digenite at 160 °C and djurleite above this temperature. Covellite was transformed to digenite at < 200 °C and to chalcocite (Q and M) at > 200 °C. The pyrite reaction was significant at > 200 °C and extensive at 240 °C, enargite reacts only above 240°C and produces digenite. The hydrothermal treatment of Chilean Codelco-type copper concentrates with hydrothermal reactions was similar to those obtained from pure mineral samples.INTRODUCTIONStudies on the hydrothermal enrichment of chalcopyrite concentrates were begun by MacGauley and Roberts (1951), Roberts et al. (1953) and MacGauley and Schaufelberger (1956). In the 1970's these processes were reexamined by McKay et al. (1972), and Johnson and Coltrinari (1976), but it not was until the 1990s when the kinetics, mechanisms and full engineering aspects were studied by Barlett, (1992), Jang and Wadsworth, (1994) and Peterson and Wadsworth (1994). The main objectives were to solve some important problems in the copper pyrometallurgy: The increase of the smelting capacity, the reduction of the iron slag – and associated copper losses – as well as the reduction of sulfur emissions. The present rise in copper demand and price implies the production and subsequent treatment of very impure concentrates. Thus, a significant increase of environmental problems can be expected in the copper pyrometallurgy. The previous purification of concentrates can reduce the processing of wastes containing hazardous heavy metals in the copper refineries and the hydrothermal treatment can be an alternative which combines both enrichment and purification. On the other hand, Chuquicamatatype concentrates (Viñals et al., 2004a) contains digenite (Cu1.8S), pyrite (FeS2), chalcopyrite(CuFeS2), b ornite (Cu5FeS4), covellite (CuS) and sphalerite (ZnS) as the main mineral components, with minor amounts of enargite (Cu3AsS4), galena (PbS) and molybdenite (MoS2)."

Jan 1, 2012

By H. R. Butler, R. N. Browne

"The International Nickel Company of Canada Limited consumes some 33 ½ millions of gallons of fresh water and reuses more than 100 millions of gallons of water daily. The continuing search for suitable recycle methodology has enabled the Company to put one 25,000 TPD mill on line utilizing recycled water entirely and a second 35,000 TPD mill is under construction which will likewise employ the concept of recycled water. Future milling plans are aimed at the replacement of all fresh water with recycled water, including sewage effluent and mine waste water.WATER REUSE AT INCO’s SUDBURY MILLSAs man searches unexplored horizons for new and economic industry, he must be constantly and acutely aware of the presence or absence of that precious commodity without which Industry, indeed Man himself, could not survive -- W A T E R. The water requirements of the world today are magnanimous, considering that in 1960 the estimated consumption in the United States was over 300 billion GPD (l) or more than 1,700 GPD per person(5) The magnitude of the problem can be visualized as one considers that three times this quantity of water will be required in the United States by the year 2000, when the dependable supplies of water are estimated to be only two-thirds of that required(2). How, then can we continue to wreak such havoc on that life-sustaining substance - WATER?"

Jan 1, 1970

By Robert B. Parsons

"Starting January 1, 1987 employers, employees, and other taxpayers are confronted with a new set of rules dealing with the taxation of travel and housing benefits relating to isolated posts in Canada, and tax deductions relating thereto. The new rules may not be the simplest in the world, but they are reasonably fair and at least offer a hitherto unknown degree of certainty as to how such allowances are to be treated. IntroductionThe first shoe fell on February 26, 1986 when Finance Minister Michael Wilson&apos; s first budget presented the framework for the future tax treatment of travel and housing benefits (so-called ""northern allowances"") provided to residents in remote regions of Canada. The second shoe fell some ten months later on December 22, 1986 when the Minister of Finance filled in the earlier announced framework with detailed rules. We now have a complete picture of the tax treatment of northern allowances. Here is what the picture looks like with effect from January 1, 1987.According to Revenue Canada, the net housing benefit to employees will be equal to the value of the accommodation provided, less any rent they have paid. In major centres such as Yellowknife and Whitehorse, having a developed rental housing market, the benefit amount will be based on the fair market value of the rental accommodation in that location. In other areas, employers will be required to value the housing benefits and, to assist employers, Revenue Canada has provided the following guidelines: Common shelter- $100 per month including the value of subsidized utilities Apartment! duplex-$270 per month excluding the value of subsidized utilities, or $400 per month including the value of subsidized utilities House-$450 per month excluding the value of subsidized utilities, or $650 per month in- c1uding the value of subsidized utilities.The amounts established as the values of accommodation will be adjusted annually after 1987 based on the housing component of the Consumer Price Index."

Jan 1, 1987

By Al Goodier

"This paper discusses the experience of Noranda Mines Limited, Matagami Division, with the vertical crater retreat (VCR) method in the mining of narrow-vein stopes. Although limited to only one stope, the viability of this method at the Radiore No.2 Mine has proven that further use of VCR in narrow-vein mining will be made.IntroductionThe Radiore No.2 property is located east of the Bell River in the southeast quadrant of Isle-Dieu Township, approximately 4.5 km east of the town of Matagami. The new James Bay Highway is 2.5 km north of the property and access to the mine is by a 2.5-km logging road.The property was staked by Radiore Uranium Mines in March 1961 and the sulphide body was first indicated by an E.M. survey. Diamond drilling commenced in the fall of 1961 and was completed by the end of 1962. As per an agreement in 1970, the claims were sold and assigned to Orchan Mines Limited. Subsequently, the property was transferred to Bell Allard Mines Limited, a wholly owned subsidiary of Orchan Mines. Early in 1979, Noranda Mines Limited acquired the property and it is now part of Noranda&apos;s Matagami Division.Geology and MineralizationThe deposit is in a band of volcanic rocks north of the Bell River complex. The lens of massive sulphides dips almost vertically and strikes almost east-west. The north contact is essentially sharp against andesite material; the south contact is less well defined, as the massive sulphides tend to grade into more disseminated material.The orebody varies from 5 to 20 feet in width, by 350 feet long and 200 feet in height. The overburden is composed of sand, gravel and clay, varying from 0 to 26 feet in depth. The ore reserves were 153,340 tons grading 1.97% copper and 1.01% zinc including 10% of dilution at zero grade."

Jan 1, 1982

By W. R. Hargrave

"Mining OperationsOre will be mined by open pit techniques. Because of the high grade of the deposit and the low strip ratio, mining rates are small relative to most other open pit operations.The ore deposit is located in the valley of the main fork of Red Dog Creek. The bulk of the deposit is located on the southwestern flank of the creek, but mineralization does traverse the creek in both the north and east directions.Erosion has exposed the orebody in a number of locations, and has resulted in oxidation of the mineralization closer to the surface. Although much of this oxide material is very high grade, it leaches readily and, at least in the initial phases of the operation, will be stockpiled and not treated in the concentrator.During construction, 2.3 million mt. (2.5 million st.) of overburden and waste will be stripped from the orebody to expose ore for initial operations. Competent non-mineralized waste will be used to build roads and waste dumps, but the bulk of material removed consists of oxide or ice-rich soils and weathered rock which is not suitable for construction.The annual ore mining rate will be 1.9 million mt. (21. million st.). The strip ratio will start off at 1.2 to 1, falling to 1.0 to 1 by year 5 and ultimately to 0.8 to 1.Bench heights are set at 7.6 m (25 ft). Pit slopes will vary depending on the material present in the wall. The slope, through competent waste and the sulphide package, was set at 45 degrees. This is flattened to 26 degrees (i.e. 2: 1) through overburden and Upper Kivalina shales. The Kivalina Shales are an ice-rich shale whose carbonate matrix has been leached out and which exhibits little or no strength as it thaws. In addition, a 100 ft containment berm will be left in the wall below overburden and Kivalina."

Jan 1, 1989

By Agbo Chima

Low-lying sections of open-pit mines accumulate water, especially during the rainy seasons, preventing access to resource-bearing areas. To sustain mining operations, the water must be lifted out of the flooded pits at a high flow rate using pumps. These pumps need to be mobile so that they can be removed during drill-and-blast operations. Most mobile pumps rely on diesel engines with high maintenance requirements. A special pump design was developed to address the unique needs of open-pit mining while making the dewatering process more sustainable. Using the target flow rate and head data, an efficient pump was designed, encased, and deployed in the open pit. A variable speed drive (VSD) was installed in a protective skid so that the pump could be tuned to match the preferred flow rate at any point during its operation. This system was tied to the national electrical grid instead of being powered by diesel pumps, which reduced the carbon intensity per kilowatt-hour. The high availability, low maintenance requirement, and greater reliability reduced the use of spare parts, the fuel consumption, and the logistics associated with operating the pump. This further reduced the carbon footprint of the dewatering process. This paper provides some of the two-year performance metrics for a deployment in West Africa. With a focus on availability, maintenance costs, average cost per volume lifted, and carbon footprint, this encased pump system is compared to the diesel-driven pumps that it aims to replace.

Jan 1, 2023