Search Documents

By K. Swedburg, M. Samuels

"The expansion of the concentrator at New Gold’s New Afton copper-gold mine in British Columbia, Canada, completed in 2015, included an increase in the required retention time of the cleaning circuit. On site pilot testing of a Woodgrove Staged Flotation Reactor (SFR) had shown that a high grade copper concentrate would be produced with excellent recovery. The SFR was selected rather than conventional tank cell technology based on the much smaller footprint (which rendered a separate and expensive building extension unnecessary), high concentrate grades demonstrated in testing, and the lower energy requirement. Three SFRs, each capable of taking a nominal feed of 700 cubic meters per hour were installed and commissioned 10 months after the receipt of order. The SFRs operate in series and all of the cells produce a final concentrate typically grading 32% Cu, while the overall SFR stage recovery averages 55%. The tailings from the SFRs are treated in the original conventional three-stage cleaner circuit where the remaining values are recovered in a concentrate grading 28% Cu. Design production was achieved within days of the initial start-up of the SFR circuit.INTRODUCTIONThe New Afton concentrator, located near Kamloops, British Columbia, Canada processes a copper-gold ore with a designed head grade of 0.96% Cu, 0.72 g/tonne Au, and 2.22 g/t Ag.The New Afton Mine is a block cave mining operation. Ore is undercut from the bottom up and removed at the extraction level from a grid of draw points. Ore is trammed to the ore passes by underground loader and dropped to a haulage level for transport by trucks to the gyratory crusher. From the crusher, the ore is conveyed to the mill via a 4.5 kilometre long conveyor system. Block caving was chosen for the New Afton deposit because the underground infrastructure could be built below the historical open pit of the Afton Mine (a previous operation of Teck Resources) and this method is favorable to large-scale low-cost mining.The New Afton deposit is a copper-gold, alkalic porphyry system. Hypogene mineralization is characterized by discontinuous copper sulphide veinlets and disseminations, principally chalcopyrite and minor bornite, along with pyrite as the second most dominant sulphide. Gold particles vary in size from 5 µm to 40 µm and occur as native gold and electrum, associated mostly with the chalcopyrite grains and never with the pyrite. In some instances, a second alteration phase has resulted in the copper sulphides being replaced by tennantite-tetrahedrite locally and along faults that transect the mineralized body. The design head grade of arsenic is 244 PPM, although the presence of tennantite is inconsistent and can vary from trace levels to 15% of the total copper. No arsenopyrite is present in the hypogene ores. Supergene mineralization, consisting of native copper with accessory chalcocite occurs in minor amounts along faults and highly oxidized near-surface portions of the deposit."

Jan 1, 2016

By K. Adham, C. Lee

The demand for nickel is continuing to exceed inventories, and producers are working vigorously to increase capacity. Many nickel processes utilize the fluidized bed technology for its fast heat and mass transfer, excellent temperature control and low maintenance. The following four nickel applications of the fluidized bed technology have been commercialized: I) Sulfide ore roasting; II) Nickel sulfide (matte) roasting; III) Nickel oxide reduction; IV) Nickel chloride pyrohydrolysis. This paper examines the issues surrounding the application of fluidization technology to the above processes, from the stand point of the engineer modeling the process and designing the key equipment, based on the historical success stories and the fundamental principles of flow sheet synthesis. Using the available data in open literature, typical flow diagrams (with convenient bases of 1 t/h feed or product) are developed to illustrate the relative flow rates and to highlight the key features of each application. In addition, some historical background information is provided for each process with supplemental notes with regards to our company's involvements.

Jan 1, 2005

By Deborah McCombe

"and Bill Roscoe, Consulting Geologist and Principal with Scott Wilson Roscoe Postle AssociatesMineral property valuations are carried out for a variety of reasons, such as mergers and acquisitions, non-arm’s length transactions, initial public offerings of stocks, support of audited financial statements, fairness opinions, determination of vendor considerations, litigation, expropriation, income tax matters and insurance claims.The CIMVal Committee was formed in 1999 to review and advise on approaches to the valuation of mineral properties. CIMVal is a special committee of CIM formed on the recommendation of the Mining Standards Task Force of the Toronto Stock Exchange and the Ontario Securities Commission.After solicitation of views and consultation with various interested parties, the CIMVal Draft Standards and Guidelines for Valuation of Mineral Properties were released for comment in February 2002 and were finalized in February 2003. CIMVal’s objective was for the standards to be used by the mining industry in general and to be adopted by Canadian securities regulators and Canadian stock exchanges. To that end, the standards contain many of the definitions and concepts of National Instrument 43-101, Standards of Disclosure for Mineral Projects, which came into force in February 2001.The intent of the CIMVal Standards and Guidelines is that mineral property valuations be carried out by appropriately qualified individuals and that all relevant information be fully disclosed. It consists of two parts: standards, which are mandatory in the valuation of mineral properties, and guidelines, which elaborate on the standards and provide guidance and recommendations for the valuation process and for reporting."

Jan 1, 2003

By M. Grenon

OBJECTIVE ?To link slope stability and financial assessment algorithms into a commercially available mine design software packages to provide integrated global pit optimization.

May 1, 2013

By K. D. Bulin

"An interesting brief history review of shovels as the primary excavating tool will permit the reader to see that immeasurable development and resources have preceded the shovel excavators which today are used extensively throughout the mining industry. With this as a background, the shovel manufacturer has the ability to utilize his resources best in those areas of shovel development in which the maximum benefits of increased reliability, performance and ease of maintenance will improve the operating rewards to the user of the equipment. The author explains the function of the shovel as a part of the material handling system. A detailed description of those areas of the shovel in which the most recent developments and major improvements have been implemented in the manufacture of the shovel excavator arc included."

Jan 1, 1973

By Farid Mirahadi

Forecasting productivity of construction operations is a difficult but crucial task in planning construction projects. Over the past decades, many models have been developed to forecast productivity for different construction operations. Models made up of several functional relations and controlled by a specific number of control rules are more in line with human reasoning and logic. Neural-Network-Driven Fuzzy Reasoning (NNDFR) structure as one of these models shows a great performance for modeling datasets among which clear clusters are recognizable. Lack of the compatibility of conventional NNDFR with fuzzy clustering algorithms besides the insufficient attention paid to the optimization of number of clusters in this model, created a potential area for further research. The main contribution of the proposed model is to develop a modified NNDFR system to model construction data. To this end, Fuzzy C-Means (FCM) algorithm is substituted for K-means in NNDFR structure, and its parameters such as the number of clusters and weighting exponent are optimized through genetic algorithm. The proposed model is further verified through simulation of a construction operation in which several qualitative and quantitative factors are considered. Its implementation to the case study shows a considerable improvement of model performance with lower Mean Squared Error (MSE). The developed model assists researchers and practitioners in utilizing historical construction data to forecast productivity of construction operations with a high accuracy that could not be obtained by traditional techniques.

Aug 1, 2013

By Robert Halupka

The industrial minerals sector represents a broad range of products involving a variety of technologies serving a diversity of markets and end uses. Unit values of products vary widely, reflecting the peculiarities of each product/market sector. Generalizations are therefore understandably difficult to make and borrowers may need to take extra time to "educate" lenders on the key aspects of their business and industry sub-sector. This paper will examine the factors and the thinking that lenders apply when considering financing proposals to companies in the industrial minerals sector. If you understand the lender's perspective and their concerns, then you can make better use of your own time and resources when arranging financing for your company or project.

Jan 1, 2001

By A. Vervoort, A. Govaerts

Geostatistical concepts are often difficult for students to understand, even those with a strong mathematical background. One of the main problems is the link between the variation of the parameter value in space or time and the calculated experimental semivariogram. Another challenge is differentiating between directional and omnidirectional semivariograms and their interpretation. For these reasons, interactive tools were developed based on the free public domain software R. The use of these interactive tools is limited to educational situations only (i.e., to visualize basic concepts). The interactive modules can be accessed at www.bwk.kuleuven.be/geostatistics.

Jan 1, 2014

By G. Simard, D. Boudeville, A. Leclerc, A. Boivin

"The objective of this work is to study the various parameters that affect the overflow clarity of gravity settlers used in the precipitation circuit of alumina hydrate from the Bayer process. A mathematical model incorporating the size distribution of the feed suspension (Multi Size Group model), its diphasic nature (Schiller Naumann model) and the presence of turbulence (Shear Stress Transport model) has been solved numerically using ANSYS-CFX software. Preliminary results indicate that the overflow clarity is mainly controlled by lateral diffusion of fine particles (~20µm) from the exit of the feed well and by their upward transport from the sediment bed interface. Also the turbulence pattern in the settling zone seems to play a significant role in this vertical transportation. The validity of the model has been verified by comparing the measured solid concentrations from a pilot classifier with the calculated ones. This model could provide mineral processing plant operators and designers with a tool to optimize the configuration of classifiers with respect to the overflow clarity.INTRODUCTIONProblemIn the Bayer process, alumina hydrate precipitation from the saturated liquor is initiated in settler by adding crystallization seeds. Most of the precipitated alumina settles to the bottom of the tank while the liquor and the remaining alumina rise to the top, where they are removed at the overflow. Ideally the overflow clarity, which depends on the operational mode of the classifier, should be controlled within targeted limits."

Jan 1, 2016

By 13409, B. Arjang

"Ground stresses are one of the significant factors in the context of rockbursts and underground instability at some hard rock mines in Canada. Overcoring strain relief measurements using triaxial strain cells were performed at several mine sites to provide stress data for stability evaluations and mine design. Pre-mining stress determinations carried out at depths between 60 m to 1890 m resulted in the following average stress gradients:Maximum horizontal stress, s Hmax = 8.18 + 0.0422 MPa/m depthMinimum horizontal stress, s Hmin = 3.64 + 0.0276 MPa/m depthAverage horizontal stress, s Ha = 5.91 + 0.0349 MPa/m depthVertical stress, a; = 0.0266 ± 0.008 MPa/m depthThe maximum and minimum horizontal compressive stresses, with an average ratio of J.75 ± 0.45, prevail in east-west and northerly directions, respectively. Horizontal compressive stresses in excess of vertical overburden load were determined, indicating large variations in ratios to a depth of about 1000 m with decreasing trend toward depth.From present data, a particular regional zoning for the magnitude and direction of horizontal stress fields cannot be outlined.A common feature at mines with near vertical orebodies is that the maximum horizontal stress acts perpendicular to strike while the minimum horizontal stress is aligned on-strike. The vertical stress components approach the gravitational overburden load."

Jan 1, 1991

By H. Langlois

"Included in the Mines Gaspe mining complex located at Murdochville, Quebec, is a copper smelter which comprises a reverberator furnace, two Peirce-Smith converters, an anode furance, and a sulphuric acid plant.The 50% smelter capacity available is supple mentedby custom concentrates for treatment. As these concentrates can be varied and extremely complex many modifications and improvements have been brought about to optimize and make the process more flexible since its inauguration in 1955.IntroductionThe copper smelter of the Mines Gaspe mining complex is located in Murdochville, a small municipality in the heart of the Gaspe peninsula, 90 km northwest of the town of Gaspe .This metallurgical installation has a daily smelting capacity of 650 tonnes of concentrate and an output of 250 tonnes of copper and 900 tonnes of sulphuric acid. Its main components are: a reverberatory furnace, two Peirce-Smith converters, one rotary anode furnace and one acid plant. The gases, which are produced by the converters, are treated at the acid plant then combined with gases from the reverberatory furnace before being vented through a 152 metre high stack .From the beginning of its operation until the present day (1991), the smelter has treated 7 million tonnes of concentrate and 100 thousand tonnes of scrap for a production of 1.8 million tonnes of copper and 2.2 million tonnes of sulphuric acid."

Jan 1, 1993

By Robert B. Parsons

"The budget that was tabled by Finance Minister MacEachen on November 12, 1981 will result in a major tax reform of Canada's income and sales tax systems, the likes of which have not been witnessed by taxpayers since 1971. All segments of the economy will be affected one way or another by the far-reaching budget proposals; the mining industry did not escape untouched.Important changes will be introduced which will alter some of the fundamentals of structuring mineral resource ventures in Canada. This month, Tax Notes examines these changes, and also summarizes the other highlights of this key federal budget.IntroductionFinance Minister MacEachen's budget, with its lower personal tax rates, loophole plugging and tax shelter bashing, represents the biggest shakeup in our tax system since tax reform in 1971. In his budget, presented in the House of Commons on November 12, Mr. MacEachen proposed substantially lower tax rates for middle and upper income individuals, with the top federal and provincial tax rate dropping to about 50%, but in return he eliminated most of the opportunities for individuals, and corporations, to reduce or defer taxes through a wide variety of tax shelter and tax planning mechanisms.Although many of those budget proposals that dealt with the resource industries focused on the implementation of the September 1, 1981 agreement reached by the federal and Alberta governments concerning the National Energy Program (see Tax Notes in the December 1981 issue of the Bulletin), the budget also contained some proposed amendments that would have significant implications for investment in the mining industry.This month, Tax Notes examines these latter proposals, and also summarizes very briefly those budget proposals which are not unique to the resource sector."

Jan 1, 1982

By H. Asgari, A. G. Odeshi, J. A. Szpunar

In the current research, the role of grain size on the texture formation and mechanical behavior of rolled AZ31B Mg alloy is investigated under shock loading conditions. The grain size of the original asrolled sample was 8 µm and different grain sizes, e.g. 25 and 46 µm, were produced by heat treatments at temperatures in the range of 400-500 °C. In order to evaluate the effect of grain size on the anisotropy of mechanical behavior, the samples were cut along the rolling direction (RD), transverse direction (TD) and normal direction (ND) and tested at strain rates of 900 and 1200 s-1 using Split Hopkinson Pressure Bar. Texture measurements showed that initial texture of the samples cut from the as-rolled sheet is a weak rtype texture. However, a stronger texture was observed for samples with large grains. After shock loading, a (00.2) basal texture developed in all samples and the intensity of the basal poles was higher in samples with coarser grains. This observation is corroborated by high twinning activity and possible activation of pyramidal <c+a> slip in coarse grained samples. Besides, the strength of basal texture increased with increase in the strain rate. Furthermore, the samples with larger grain size showed lower strength and higher ductility, and this was observed for all investigated strain rates.

Jan 1, 2014

By Alireza Sarafi, Alijan Aftabi

"A hydrocyclic system used for mineral separation at the laboratory scale results in the separation of more than 90% of micas. The system functions only by water and might offer advantages where other methods of mica separation are not available. INTRODUCTIONVarious methods for the separation of micas, wollastonite, and garnet, e.g., screening, flotation, magnetic separation, and heavy liquids, are well known (e.g., Spence, 1929; Bates,I960; Gillson et al., 1960; Benjamin, 1971; Connor and Kolhnar, 1991; Collings and Andrews, 1991). However, where these methods are not available, the separation of micas by a hydrocyclic system developed by Sarafi and Aftabi (1991) may prove to be economic. This note is a brief description of the hydrocyclic system. Minerals and MethodFor testing the recovery of mica and other minerals from different rocks (garnet-mica schist, skarn, and pegmatite), standard minerals were tested first, and then rock samples. Pure mineral standards were prepared from coarse-grained samples of pegmatite, mica schist and skarn; the grain size of the minerals separated was more than I cm. The Hydrocyclic System and Mineral SeparationThe hydrocyclic system is shown schematically in Figure 1. In the first step in mineral separation, mineral and rock samples were crushed, milled, and then sieved to minus 250 plus 125 microns. Approximately 10 gm to 25 gm of the sample were inserted in decanter Dt • The motor pwnps, M1 and M2, were then turned on and the water valve rl was opened. At this time, water was flowing turbulently (30 em3/sec. to 50 em3/sec.) and minerals were separated according to their crystallographic nature, density and!or habit. The fInal separation was done by exit valves r2, r3 and r4, while the motor pwnps were still operating. After each experiment, the rt , r2&apos; r3 and r4 valves were closed and the motor pumps were turned off. Following this, minerals in each decanter and the mter were collected, dried and weighed. The whole time of the experiment was optimized to be about 10 minutes, but varied from 3 to 15 minutes for micas and garnets. respectively."

Jan 1, 1994

By J. Nsasi Bakambu

This paper describes an autonomous platform for exploration and navigation within networks of tunnels, as those typically found in underground mines and caves. In the exploration mode, a remotely located supervisor instructs the platform to move through successive sections of the network, gathering range data that is, then, concatenated into 2D/3D survey maps of the environment. In the navigation mode, the supervisor specifies high-level missions on the previously acquired survey maps. A motion planner, then, translates each mission into a set of consecutive navigation actions, separated by natural landmarks. Mission execution consists of detecting landmarks, self-localizing and performing the planned navigation actions.

May 1, 2003

By Gary M. Bone

The autonomous control of vehicles interacting forcibly with their environment, such as dozers and tractors, is an unsolved and challenging problem. Forces and motions are inherently coupled between the tool and the means of vehicle propulsion. Furthermore, they are often operated within uncertain and unstructured environments, such as those encountered in underground mining. There is a growing industrial interest in the development of robotic vehicles to improve productivity, efficiency and safety in mining and construction. This paper focuses on the modeling and control of autonomous robotic dozing for a material removal operation. A dozing process model has been developed based on observations of both a fullscale dozer and a scaled-down version. The model characterizes the dynamic interactions between the blade position, material accumulation on the blade, material distribution in the environment, and the motions of the dozer. The dozing control objective is to remove the loose material as rapidly as possible by driving forwards at full power while automatically raising/lowering the blade in response to sensor measurements. Two different controllers were developed to meet this objective. The first controller is based on a set of heuristic rules, and the second is an optimal controller based on the dynamic model. An instrumented scaled-down robotic dozer and dozing environment, designed to emulate the full-scale operation, are used to implement the controllers and compare their performances over multiple dozing passes. Experimental results are presented showing that the model-based controller increased the material removal rate by 33% compared to the rule-based controller. Lastly, technologies for full-scale implementation are discussed, followed by proposed future work and conclusions.

Aug 1, 2013

By A. M. Brown, P. V. Straznicky

Dimpling as a means of flush countersinking rivets is an old process predominantly used in secondary structures. The introduction of GLARE as an aerospace material has renewed interest in dimpling and its possible application in primary structures. The dimpling process is able to prevent the creation of a machined knife-edge in the thin aluminum plies of the GLARE sheets. In addition, dimpling eliminates the need to use reduced height rivets, such as the NAS 1097 rivet style. This investigation expands on an earlier study into dimpling of GLARE by Rans and Straznicky. In order to tailor the dimpling process to GLARE, FEM simulations were developed. After verification, a study was performed to find the best parameters for dimpling GLARE3-2/l. Coupon fatigue tests were carried out and the dimpled joints demonstrated increased fatigue lives over the conventional machine countersunk joints. Future wide panel fatigue tests are planned to confirm the usefulness of dimpling thin GLARE laminates.

Jan 1, 2006

By Narasimha Mangadoddy, Teja Reddy Vakamalla

"Vertical hydrocyclones are very common in most of the comminution circuits. Inclined cyclones are also found for specific mineral processing applications. In this work, Computational Fluid Dynamics (CFD) technique and experiments are used to find the reasons behind the inclinations effect on hydrocyclone performance characteristics. The water and silica slurry experiments are conducted with 75 mm hydrocyclone at different inclined positions (0-600) to the vertical plane. Corresponding two-phase numerical simulations are performed with Volume of Fluid (VOF) model coupled with Large Eddy Simulation (LES) turbulence model. Multiphase simulations are carried out with Algebraic Slip Mixture model modified with lift, drag forces and Newtonian rheology model corrected with fines for various feed solids concentration. A raise in the under flow solids percentage, cut diameter and a reduction in the water split is observed with the inclination. Electrical Resistance Tomography (ERT) and High Speed Video (HSV) data is used to cross validate the inclined cyclone’s CFD air-core and solids concentration data. Predicted efficiency curves are found in a close agreement with experiments for all the inclinations. Comparison of experimental and predicted flow data clearly follows trend with the literature. Key words: Hydrocyclone, CFD, ERT, inclination, water splitINTRODUCTIONHydrocyclones are devices used to separate or classify particles based on particle size difference in the water medium. Their usage is very wide in chemical, petroleum, mineral and bio industries due to its structural simplicity, high throughput, small volume, low cost and maintenance. Cyclone mainly consists of a cylindrical section followed by a conical section attached to a single feed inlet and two product outlets named vortex finder and spigot. It works on the principle of centrifugal sedimentation. The slurry is fed tangentially to the hydrocyclone, in which larger particles are moved towards the wall and separated by centrifugal forces to the underflow. Smaller size particles follow liquid due to drag forces to the overflow. With its simple structure, the flow behavior inside the hydrocyclone is quite complex. Vertical cyclones are common in practice in most of the comminution circuits. Horizontal cyclones can be found in extreme cases which are for installation convenience rather than for process reasons. Inclined cyclones are also present for specific mineral processing applications. In coal preparation plants, dense medium cyclones are operated near to horizontal inclination of 20 degrees to allow large spigot sizes for sinks removal, self-drain of contents during shutdown. In the phosphate removal, dense medium cyclones are inclined with an angle between 0-90 degrees for better separation of ore and tailings (Liu Feng et al., 2006). Even in the clusters, hydrocyclones are mounted with an inclination around the feed distributor for uniform distribution of slurry and under flow collection. It is believed in mineral processing industry that inclined cyclones would fetch the benefit in number of ways while classifying the material by size. Gravity influences the cyclone performance through the air core size and position variations in large cyclones. It also favours the cyclone operation at coarser cut points without varying any other design and operating parameters. Minimizing fines misplacement to underflow can be achieved with inclination."

Jan 1, 2016

By R. J. Young, S. J. Tennant, A. D. Drummond

"Gibraltar Mines is located on the western slope of Granite Mountain, 230 air miles north of Vancouver, B.C. and 38 miles north of Williams Lake, B.C. There are four mineable zones within the copper-molybdenite deposit: Gibraltar East, Gibraltar West, Pollyanna and Granite Lake. Open-pit reserves are 358 million tons which average 0.37% Cu and 0.016% MoS2 at a 0.25% Cu cut-off. The Granite Mountain pluton is one of the several Jurassic-Cretaceous intrusions which outcrop along the east side of the Fraser River fault system between Williams Lake and Prince George, B.C. The original Granite Mountain quartz diorite has been metamorphosed by a cataclastic deformation which foliated the rock on a regional scale. Attendant to the development of the foliation, the rock was saussuritized such that the present mineralogy is compatible with that of the greenschist facies. The presence of garnet-bearing assemblages is explained by a restricted increase in water pressure. Pre-mineral intrusive phases within the saussuritized quartz diorite are: (1) leucocratic quartz diorite, (2) aplite and (3) quartz-feldspar porphyry. A late chloritized hornblende dacite dyke is post-mineral. Quartz-feldspar porphyry and leucocratic quartz diorite are locally present on the inner sides of the Gibraltar East, Pollyanna and Granite Lake pits. Their presence suggests a core around which occurs an elliptically shaped sulphide-bearing stockwork. The stockwork, which comprises four ages of vein development, is imposed on and partly controlled by the regional foliation of the samssuritized quartz diorite."

Jan 1, 1973

By D. J. MacDonald

UNDERGROUND development at the Lynn Lake property of Sherritt Gordon Mines, Limited, was begun in 1948 with the sinking of the A shaft in the area of the A orebody. By June, 1949, the shaft was completed to a depth of 1,024 feet. Twelve stations were cut, with the bottom level at 992 feet below the collar. Since completion of the shaft, lateral work has been carried out on the 12th level in order to expose the known orebodies and to provide openings from which deeper exploration could be conducted. Dur¬ing the change-over from sinking to lateral work, preliminary diamond drilling was done from the 12th level station to locate the A? ore-body. Later, drilling was carried out from the 5th and 9th level sta-tions, where, also, the outline of the A orebody was established. As the work progressed on the 12th level, and with the commence-ment of drilling below that level, the geological picture was found to be complicated by numerous faults. Instead of operating two drills it became necessary to use at least four. The original plans had provided air sufficient to drive two headings and to operate two diamond drills. The addition of two more air-driven drills resulted in a serious shortage of power.

Jan 1, 1951