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Abstract: ?The paper will review the perspective of Scotia Capital on financing mines, mining projects and mining companies in today's world of major increases in commodity prices, increases in capital and operating costs, shifts in foreign exchange rates, and increasing scrutiny of mining's social license ?Focus on debt financing alternatives Key Assumptions: ?Assume financing a mining asset (i.e. not an exploration play) ?Exploration is generally financed with equity ?private placements or public offerings on an idea

May 1, 2006

By H. Dundar

An extensive testwork was performed around the HPGR plant at GoldFields Ghana Limited Tarkwa Gold Mine. The HPGR was used to prepare the feed for heap leaching. The circuit was configured in such a way that the edge material from the HPGR discharge was recycled for further crushing while the product from the centre reported to the heap leach section. The set-up of the Polysius HPGR provided an opportunity to study the effect of different design and operating variables. This paper will discuss the results from the tests performed to assess the effect of rolls? speed and applied pressure on the capacity and the grinding efficiency of the HPGR. Applying different pressure values appeared to have an influence on the amount of edge material recycled.

Jan 1, 2012

By S. A. Vazhnov, A. G. Kalimov, A. A. Potienko

In this paper we describe a mathematical model of the magnetic field and magnetohydrodynamic processes simulation in aluminum reduction cells developed in St. Petersburg State Polytechnic University, Russia. The model includes: (a) calculation of the currents in the busbar system and inside the aluminum cell construction elements including cathode and anode structures, aluminum and electrolyte layers; (b) magnetic field simulation using the integral equation method; ( c) investigation of the magnetohydrodynamic characteristics on the basis of a shallow-water approach. The developed model was used to investigate operational characteristics of the different industrial aluminum cells. Calculated magnetic field distributions and MHD stability parameters were compared with the available experimental information; the comparison demonstrated a reasonably good agreement.

Jan 1, 2006

By Magdy Ibrahim

Detailed as-built project schedules are necessary to close out construction projects, benchmarking, forecasting, dispute resolution, and improving cost estimates of future projects. Manual procedures for developments of as-built documentation is time consuming, involves numerous interfaces and human interventions. This paper presents computational framework that encompasses automated site data acquisition and generates schedule updates utilizing commercially available project scheduling software. The work is carried out collaboratively with a Hydro Quebec team. The site data is captured employing mobile computing using iPad® type computers and Wi-Fi. The information is directly compiled in a centralized database server. The synchronization tool is a bi-directional application and is used on servers to communicate with iPad® computers deployed onsite. The captured data is stored in Microsoft SQL® relation database that consists of 63 entities. Computer software application has been developed in Microsoft Visual Basic® (vb.net) environment for extracting the collected site data, linking the database to the as planned schedule, and generating the actual, also known as as-built schedule. The development can be utilized in automated progress reporting, evaluating future bids, generating master schedules and a wide range of efficient EVM applications.

Aug 1, 2013

By Ali Hashemi, Anna P. Perry

The PQ Deeps (PQD) is a production zone located at Newmont’s Musselwhite Mine in northern Ontario. Development started for the PQD in late 2017, and the first stopes were mined starting in early 2021. Unlike most historic longitudinal stoping of narrower orebodies at Musselwhite, the PQD is a wider orebody following the plunge of a fold hinge and is extracted primarily by transverse stoping. Some geotechnical challenges were experienced during early stoping efforts, necessitating design changes throughout late 2021 and early 2022 to optimize the stope design. This work describes the mining methods and design changes to transverse PQD stoping based on geotechnical lessons learned during early stoping efforts.

Jan 1, 2023

By C. J. Simensen, R. Østhus, H. J. Roven, K. G. Skorpen, H. Kalager

"This work encompasses co-extrusion of alloy Al4.5Mg at the core and rapidly solidified Al4.5Mg1Ag forming the surface layer. The goal is to produce a multi-material by co-extrusion having a relatively hard surface as compared to a softer core. At the same time, work hardening in both alloys is expected to be significant due to Mg in solid solution. Precipitation hardening at 160°C is studied by applying solution heat treatments at 560°C. The hardness increased from 80 to 130 VH in the surface material after 236 h. Surprisingly, the Al4.5Mg alloy also shows pronounced aging at this temperature, i.e. from 70 to 90 VH. The relatively high solution heat treatment temperature introduces grain growth in the core, but this is insignificant for the RS surface alloy. Blisters forms at the surface and cracks follows large portions of the interface. However, the tensile ductility is significant in all conditions due to very pronounced work hardening, i.e. for the as co-extruded, T6, under- and over-aged. The elongation at fracture ranges between 40–45% and the tensile strengths 240–275 MPa. The tensile properties increase linearly with the thickness of the RS alloy, i.e. following the rule of mixtures.INTRODUCTION Al-Mg alloys in 5xxx-series are classified as non-heat treatable wrought alloys (Polmear, StJohn, Nie, & Ma, 2017). The formation of the binary ß-Al8Mg5 does not give a substantial increase in the strength of the alloys (Mondolfo, 1976). When a third element like Ag, Cu or Zn are added, G.P.?zones are formed at low temperatures and intermediate, partial coherent phases are nucleated somewhat higher temperatures and finally a ternary, equilibrium phase is formed (Auld, 1968; Cousland & Tate, 1986; Mondolfo, 1976). Both the formation of G.P.?zones and intermediate phases increase the hardness and strength of the materials. An intermediate, hexagonal T´?phase is formed in Al-5 wt%Mg-1wt%Ag, and finally the equilibrium, cubic phase (Al,Ag)9Mg5 is nucleated (Cousland & Tate, 1986; Mondolfo, 1976)."

Jan 1, 2018

By Seungwoo Park, Whuisu Shim, Roe-Hoan Yoon, Kaiwu Huang

"A comprehensive froth model has been derived from first principles. It is based on predicting the kinetics of film thinning in the presence of particles of varying sizes and surface hydrophobicity. According to the Reynolds lubrication theory, the thinning of a horizontal film is driven by the excess film pressure (p), which is determined by the capillary pressure (pc) and the disjoining pressure (II). In the presence of particles, macroscopic capillary pressure (pc) is affected by the local capillary pressure (pc,local) in the vicinity of a particle and the number of particles in the film (N1,film), which in turn vary with the hydrophobicity and size of the particles. The Reynolds equation corrected for pc,local and N1,film is then used to predict the time (or froth height) at which a film is thinned to a critical rupture thickness (hcr), which in turn can be predicted using the Vrij’s capillary wave model (1966) after a modification to incorporate the contributions from hydrophobic disjoining pressure (IIhp). The model can predict bubble coarsening represented by the bubble size ratio between the top (d2,t) and bottom (d2,b) of a froth as functions of particle size and hydrophobicity, ? -potentials, frother dosages, froth height, gas flow rate, salt concentration, etc. The model predictions have been verified in experiments.INTRODUCTIONFroth flotation is regarded the best available technology today for upgrading minerals and coal fines. In the pulp phase of a flotation cell, air bubbles collect hydrophobic particles dispersed in it and rise to enter the froth phase on the top. Once in a froth phase, the bubbles coalesce with each other and become larger, resulting in a decreased bubble surface area. Under conditions of limited surface area, less hydrophobic particles drop off the bubble surface and return to the pulp phase. Thus, bubble coarsening provides a useful mechanism of increasing product grades. On the other hand, uncontrolled coarsening results in a decrease in bubble carrying capacity and hence throughput."

Jan 1, 2016

By Kevin Azocar, Jim Hazzard

"Slope stability analysis is performed most commonly using limit equilibrium calculations or numerical models assuming a two-dimensional slice through an infinitely long slope surface. In areas such as open pit mining, where most slope surfaces are not planar, the importance of curvature becomes important due to the economic gains associated with creating a steeper slope. With advances in computing capabilities within the last decade, three-dimensional slope analysis can be performed within reasonable time frames. Some work has been done on the potential importance of curvature on slope stability, mainly assuming homogenous materials with a circular shear-failure mechanism. However, many open pit mines are excavated in jointed rock mass where a completely different set of failure mechanisms can be seen. Depending on the geometry and radius of the pit, the curved geometry may influence the factor of safety and failure behaviour compared to a two-dimensional slice.A series of numerical analyses were performed to investigate the effect of curvature on jointed rock slope stability compared to an equivalent two-dimensional slope analysis. By using discrete element method models, the influence of joint planes and interaction between distinct blocks can be seen. With a three-dimensional model, the effect of curvature can be combined with multiple joint sets at any orientation, which cannot be seen in a single slice. Numerous three-dimensional models are created, along with an equivalent unit-thick slice. The effect of curvature on a variety of different types of failure mechanisms is observed, and graphical relationships are created to quantify the difference between the three-dimensional factor of safety and the two-dimensional factor of safety based on the degree of curvature."

Jan 1, 2015

By R. B. Allen, B. S. W. Buffam

"The property of Chesterville Mines, Limited, is in McGarry township, Timiskaming district, Ontario, about 25 miles east of Kirkland Lake. It consists of a group of fifteen claims that extend northeast from the KerrAddison mine for a distance of 2 miles.In June, 1906, two groups of prospectors left the town of Chesterville, Ontario, to prospect in northern Ontario. Silver had been discovered 3 years before at Cobalt and the large profits of this young mining camp were the principal incentive to extending the field of exploration northward. One group consisted of Dr. Reddick, Edward Flynn, John Hummel, William Knott, and Colin Cameron. The other group comprised J. T. Kearns, Herman Hummel, W. G. Barkley, and J. Elliott.The two groups travelled north by train to Haileybury and thence to Larder lake by canoe. Camps were pitched on the northeast arm of the lake, and within a short time a discovery was made by Edward Flynn of the first party, who found gold on the property now owned by Kerr-Addison Gold Mines, Limited. Herman Hummel and J. T. Kearns shortly afterwards made the second discovery, on what is now the Chesterville property. These discoveries, made some years prior to those at Porcupine and Kirkland Lake, are believed to be the first in that part of northern Ontario.The Hummel-Kearns claims were incorporated in the following year under the name of Chesterville Larder Lake Gold Mining Company, Limited. It was not, however, until 30 years later, in 1936, following the increased premium on gold, that sufficient capital was placed in the treasury of the Company to carry out an extensive diamond drilling programme. This exploratory drilling was started early in 1937 under the direction of Leo. J. Kearns, and a large body of ore was intersected in the first drill hole. Underground work was started in 1938, a mill was built, and the first gold brick was poured on July 29th, 1939."

Jan 1, 1954

By Donald J. MacNeil

The commercial carbonate industry of Cape Breton Island, Nova Scotia, began about eighty years ago with the opening of the Sydney steel plant. Significant carbonate deposits are confined to the Precambrian George River Grav" and the Mississippian Windsor Group. George River Group carbonates are thought to have formed as part of a stable platformal sequence. They are crystalline and lie within a dominantly quartzitic sequence. Of the four major sites for George River carbonates on the island, the most commercially promising are the dolomite at Kelly Cove and the limestone and dolomite at Glencoe. Kelly Cove dolomite has good potential for metallurgical, agricultural and fettling purposes; reserves approach 13.6 million tonnes. Windsor Group carbonates were deposited as marine sediments in basins formed by pre-Carboniferous fault blocks. Windsor dolomite reserves at Stoney Creek are only fractionally retrievable and hence are of little economic value. The Windsor Group's Irish Cove limestone has been quarried on a large scale since 1964; no undeveloped commercial deposits, however, remain in the group.

Jan 1, 1984

By N. W. Martison, J. E. Hawley

"The Moulton Hill deposit is in the Eastern Townships of Quebec, 3 miles northeast of Sherbrooke. It is complex, both structurally and mineralogically, consisting of a narrow, irregular, mineralized zone that has been traced for a length of 600 feet, and in places to a depth of 1,000 feet, containing copper, lead, and zinc sulphides with a low content of gold and silver. It lies in a series of highly schistose micaceous rocks, believed to be of Ordovician age, but the mineralization is probably post-Lower Devonian. New details of the structure of the ore have become available since it was first described (1) , and as these show some striking peculiarities a further discussion is here merited .As detailed elsewhere, the deposit was discovered in 1942 as a result of regional geological studies followed by the application of electrical geophysical methods.Actual production began in July, 1944, and ceased in June, 1945. During the period July, 1944 to June, 1945, 75,643 tons were milled§, yielding the following:"

Jan 1, 1954

By Z. Q. Yue

Many large rock avalanches and/or landslides have occurred in mountainous regions around the world. Their occurrences are normally rapid and unexpected, which can cause disasters. They have been investigated extensively by many researchers and engineers since the 1903 Frank Slide on Turtle Mountain, Alberta, Canada. They are one of the most peculiar phenomena because the rock debris of more than one million m3 can move over the horizontal distances exceeding those expected from conventional friction physics. This paper presents a gas cause hypothesis responsible for the large rock avalanches. It is the migration and expansion of a certain amount of highly pressurized and dense natural gas mass from deep geological grounds into the mountainous rock mass slopes. The natural gas with high pressure and density can escape from the deep geological ground and flow through faults, weak zones and/or porous channels into the rock mass forming a mountainous slope. The rock mass forming the slope has the high tensile and compressive strength and can resist the initial loading of the gas mass migrated into and stored in their voids, pores, holes, gaps, openings, apertures and cavities. With time, more and more gas mass from deep ground can migrate into and stored in the slope rock mass. Eventually, the peak equilibrium of forces and deformation reaches. The expanding power of the gas in the slope rock mass would instantly and rapidly break, erupt and/or explode them. The compressed and dense gas mass would mix, flow and expand together with the broken rock debris mass and continue offering their remaining expanding powers to the moving and sliding debris mass. As a result, the rock debris of large volume can reach the runout distances exceeding those expected from the conventional friction physics. The gas would escape into the sky and the solid rock debris would remain on the ground spreading over large ground area. The 1903 Frank Slide is examined to show this gas cause and mechanism in mountainous regions.

Jan 1, 2015

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

By Lin Li, Ahmad Ghahremaninezhad

"In this paper, the electrochemical behavior of ferric and ferrous couple on the pyrite surface was studied by application of the chronoamperometry technique in an acidic solution at room temperatures and atmospheric pressure. The effects of the pyrite origin, ferric and ferrous ions concentration on the electron transfer kinetics of Fe3+/Fe2+ reaction were probed. Tafel behavior of all the test conditions were developed. The results showed that the ferric-ferrous reaction on pyrite electrodes with different origins have a common mechanism, despite different reaction kinetics. The exchange current densities of the redox reaction have the same magnitude of about 10-5 A·cm-2, which is far lower than the value reported for the gold and platinum electrodes, but larger than that of the chalcopyrite electrode. The cathodic transfer coefficients are between 0.4 and 0.5, while the anodic transfer coefficients appear unusual with the lowest value being 0.23. It was also demonstrated that an increase of one order of magnitude of iron concentration has no clear effect on the exchange current density and cathodic transfer coefficients of Fe3+/Fe2+ redox reaction.INTRODUCTIONPyrite, FeS2, is mostly considered as a gangue mineral which frequently coexists with valuable minerals and metals, such as gold, copper and nickel. Its separation from valuable minerals can be a costly process (Chandra & Gerson, 2010). In refractory gold ores, the fine gold particles are locked inside the pyrite structure. Oxidative leaching of pyrite is a hydrometallurgical method to destroy the structure of pyrite and expose the fine gold particles to the cyanide solution in the downstream cyanidation circuit. Pyrite oxidative leaching can be achieved by oxidation of pyrite via oxygen and ferric ion(McKibben & Barnes, 1986). In fact, pyrite oxidation by oxygen and ferric is a significant source of acid mine drainage(AMD), which adversely causes serious environmental problems(V. P. Evangelou, 1995).The pyrite oxidation mechanism is accomplished in three consecutive steps: (i) pyrite is oxidized by oxygen and ferrous ion formation (Eq. 1); (ii) ferrous oxidation by oxygen and ferric ion formation (Eq. 2); (iii) pyrite oxidation by means of ferric ions (Eq. 3). Hence, both oxygen and ferric participate in the pyrite oxidation process (Moses & Herman, 1991):"

Jan 1, 2016

By Karen M. Moffitt

Developments in mining methods and rates have led to an increase in the frequency and size of waste dump failures that have not been adequately predicted or explained in terms of conventional slope stability analysis. Monitoring data and visual observations suggest a unique mode of failure responsible for large runout events. A numerical model has been developed to capture commonly observed patterns of deformation, and investigate the formation of the ensuing failure mechanism. The analyses have yielded a good correlation with observed field behaviour and have provided significant insight into the coincident stresses and deformations within the dump. Results indicate that while creep effects in the waste dump could have a significant effect on the magnitudes of displacement, the overall dump stability is governed by the strength of the foundation soils underlying the toe region. Consideration of both the stress and velocity fields leads to factors of safety for various dump heights and foundation slopes that are considerably less than predicted from limit equilibrium analysis. The results suggest that conventional limit equilibrium analysis techniques may not be adequate when assessing the stability and design of waste dumps on steeply sloping terrain.

May 1, 2001

By A. F. Robertson

FOR several years, the rock-burst question has been given serious consideration by the operating staff at Wright-Hargreaves mine and, as a result of observations and experiences, several different methods of mining have been developed which are now in use in various parts of the mine. These are described in the following pages. It should be emphasized, how-ever, that these methods, and the views expressed in this paper, are based solely on conditions at Wright-Hargreaves mine. Such conditions may or may not be similar to those obtaining in other mines in the Kirkland Lake area, where ore occurrences, veins, wall-rock, faulting, intrusives, etc., may be entirely different. Size and shape of ore-bodies, composition of the ore-bodies and their surrounding rocks, locations of intrusives and sedimentary rocks, and direction, dip, and strength of faults, all introduce problems that are peculiar to each individual mine. Ground failure' in coal and metal mines is not at all unusual. A variety of systems of mining have been developed to delay movement of large or small blocks of ground, or, in some instances, to take advantage of the fact that ground movement, due to mining operations, is unavoidable. Ground failure may be either slow collapse or it may take place with explosive violence. It is principally with the latter condition that we are concerned in the mines of the Kirkland Lake district.

Jan 1, 1939

By Richard Hurteau

Design and validation of an integrated guidance system for articulated ground vehicles is investigated. The development of an autonomous industrial vehicle must take into the account the specific geometry of these vehicles; they can be composed of a tractor with 1 or 2 trailers or of articulated type like LHD. Moreover the tractor-trailers type vehicles can have on-axle hitch configuration or positive/negative off axle configuration. The path-tracking of a tractor-trailer vehicle in restricted space is presented and discussed in this paper. Recent results obtained in simulation and validated by experimentation are also presented. These studies can lead to better ways of maneuvering an articulated vehicle in a restricted space or automatically executing of docking and parking maneuvers

May 1, 2002

"The Kidd Creek concentrator is situated adjacent to Highway 101, twenty-four kilometres east of the center of the city of Timmins, Ontario. Sulphide ore, received by train from the minesite twenty-nine kilometres away, is processed at a rate of twelve thousand metric tonnes per day. Saleable concentrates of copper, zinc, lead and tin are produced.The concentrator contains secondary crushing, grinding, flotation, gravity separation and concentrate handling facilities. The total concentrator manpower complement is one hundred and sixty-four which includes supervision and operating personnel. Twenty-one shift personnel are required to operate the processes involved and they occupy fifteen different operating positions in addition to that of the supervisor. These positions include:1 Central Control Operatorl Metallurgical Leader1 Dryer Control Operatorl Crusher Leader3 Copper-Lead-Zinc Flotation Circuit Operators1 Pyrite Flotation Circuit Operator1 Tin Plant Operator2 Grinding Operators1 Concentrate Operator2 Crusher Operators1 Spare Operator1 Tailings Area Operator1 Automatic Sample System Operator1 Dryer Area Helper1 Crusher Helper1 Tin Plant Helper"

Jan 1, 1981

By G. V. Lewis

"INTRODUCTORY REMARKS""I believe we need to communicate as much as possible with the industry. I don't think that we should be a body that just goes around doing dust surveys and writing nasty letters. We should get together on these problems and try and solve them as a group. I've only been with the Department a little over 12 months. I haven't visited all of your plants. I've visited most of the major open pits and I have had a chance to observe a lot of problems that you have encountered and a lot of the problems that you have brought up this morning. I thought the best thing I could do is perhaps mention a few of the approaches to the problems that my superior has suggested to me and we have discussed in the Department, and then perhaps go over a few of the evaluating problems and what we are trying to do with our dust surveys and perhaps ways and means of improving the present setup."""

Jan 1, 1976

By Jessica Hurst, Mark Holdsworth, Jeff McKay

"In 2002, Kennecott Utah Copper Copperton Concentrator installed an Expert Control system for optimization of their SAG and Ball milling circuits. The advanced process control has been well received and is utilized well over 95% of the time. In the years since, many lessons have been learned and many advances have been made. Improvements have produced millions of dollars of benefits and have included directly controlling feedrate with complex logic as opposed to using a bearing pressure controller, modifications to how sound is used for control, modifying logic for maximizing asset utilization and using advanced control for automating equipment restart. INTRODUCTIONRio Tinto’s Kennecott Copperton Concentrator produces copper, molybdenum, gold and silver. The mill has 4 SAG mills (SAG 1-3, 34 foot diameter and SAG 4 36 foot diameter), 8 ball mills and copper and molybdenum flotation plants, as seen in Figure 1. The 2010 average data is shown in Table 1.In 2002, a Metso Cisa OCS Expert Control system was installed at Copperton for SAG and Ball mill advanced control. The expert control was first placed on SAG 2; data from the first few weeks compared with operator performance indicated approximately an 11 percent increase in throughput. After full commissioning, the system was gradually refined further by plant personnel to develop key performance indices based on SAG feed size, refinement of the sound setpoint for control of mill speed and throughput, specific rules to help the adjustment of speed based on loss of a feeder, etc. With the addition of the pebble crushing circuit, the expert control began utilizing a model estimation of crushed pebble bin level to help stabilize the impact of returned crushed and uncrushed pebbles on the SAG mills. As the ore and limitations change, it is necessary to evolve the SAG logic to better handle any constraints."

Jan 1, 2012