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By D. Mark Richards

Highland Valley Copper (HVC) is a large open pit copper mine in the southern interior of British Columbia. Machine guidance technology using GPS has been utilized at the mine since 1996 for blast hole drill navigation and since 2000 for shovel and dozer navigation. Since 1997, rock recognition has been part of the drilling process. This allowed the mine to develop a Mine to Mill strategy using the rock hardness information from drill monitoring systems to both refine drilling and blasting parameters as well as downstream crushing and grinding strategies. Although this preliminary effort has been very successful at HVC, the current intent is to gain further benefits through better use of existing information while also deriving an enhanced data set from monitoring production drills. In the latter case, the objective is to acquire and process drill variables in such a manner as to permit more detailed definition of rock mass characteristics. The subsequent focus will be to use the derived geotechnical and geological information as part of a practical process to more prescriptively blast the rock mass. Through the definition of domains based on drill monitored derived rock mass properties, the intent will be to enhance blast outcomes that lead to optimized downstream (from blasting through to concentration) processes in a more proactive and timely manner. This paper examines a proposed approach to be able to derive more accurate and consistent rock mass properties from production drilling. In addition, the discussion will identify potential benefits to be gained from process improvements that result in enhanced productivities, and crushing and grinding optimisation due to blasting strategies that are more closely matched to identify rock mass characteristics.

May 1, 2007

By T. Yeomans

NVI Mining’s Myra Falls operation is a forty-year-old underground mining operation feeding a 4,000 metric tonnes per day concentrator. The current mill, built in 1985, was designed to process a massive sulphide ore-body. This orebody, known as the HW, contains about 50% pyrite. Minerals of value are chalcopyrite and sphalerite, with precious metals occurring in all mineral types. By 1997, mining of a new ore-body, known as Battle-Gap, commenced. Mineralogically complex, the new orebody contains about 15% pyrite copper minerals, including primary chalcopyrite and secondary bornite, chalcocite and tennantite, combined with increased galena and sphalerite. Flotation performance generally decreased with increasing amounts of Battle-Gap ore types, with both copper concentrate quality (increased lead and zinc content) and copper recoveries being affected. Following significant metallurgical test-work, a new, fully sequential copper-lead-zinc flotation flow sheet and reagent scheme was developed. This sequential flow sheet was progressively installed and commissioned during 2006. Copper concentrate lead and zinc smelter penalty contents have been reduced by some 40%, while increasing copper recovery by 10%.

Jan 1, 2009

By Quin Dennis

Process Optimization ?What is it really? It is NOT ?a larger fan to increase draft through a process ?a larger pump on a wet circuit ?a wider conveyor belt for solid materials ?a larger feed elevator into or out of a process These relieve individual constraints ??bottlenecks??and allow operation to the next constraint in the process ?It is also NOT about automating the operator ?which captures consistency but is not continuous optimization

Nov 1, 2011

By A. M. McKim, J. S. Ambler

"The iron ore of the Scully Mine is upgraded from 36 per cent Fe to 66 per cent Fe through single-stage crushing, wet autogenous milling, sizing by vibrating screens and two-stage spiral separation, followed by a process in which the concentrate is dried and then further improved by high-tension separators. The capacity of the concentrator is 17,000 long tons of concentrate per day. Discussion of the operation will recognize the special problems encountered in handling preponderantly fine ore, relate issues of interest regarding wear and review mechanical innovations found to be advantageous at Wabush. The modern trend toward big equipment, thoroughly instrumented, has been the theme of design. Effects on availability must be a consideration in this choice, and sectionalizing of circuits to minimize these consequences is as important as streamlined maintenance."

Jan 1, 1969

By B. S. Ignasiak, Dennis Carson

"Laboratory study of the behaviour• of binary coal blends shows that coke strength is more closely dependent on the distribution of ""reactive"" oxygen in the parent coals than on their proximate, elemental or petrographic compositions, and it also appears possible to qualitatively predict coke strength from information about reactive oxygen. Proceeding from this recognition, experiments were carried out to test the possibility of preparing metallurgical cokes from binary blends in which non-caking hvb coal was substantially freed of reactive oxygen by prior heat t1•eatment under controlled conditions. The results indicate that such blends can yield surprisingly strong cokes and that coke strength may be amenable to further improvements by modifying the size distribution of the pre-heated component and the rate at which it is charred."

Jan 1, 1976

By David Whalen

Mobile equipment in oil sand mining operations experience more maintenance problems than similar equipment in other surface mines, due to soft underfoot conditions. Oil sand properties are known to vary with temperature, bitumen content and previous loading cycles. One of the challenges is the widely variable underfoot pressure which supports shovels and trucks. In the case of a heavy hauler driving on in-pit roads, each tire is supported by a different ground stiffness resulting in an apparent uneven surface. Driving over uneven ground causes twist in the truck frame, which is transmitted to the dump body. Through a finite element analysis of a haul truck dump body, it was shown that slight frame twists produce localized stresses in the intersections of the floor stiffeners. These stresses are at times greater than those resulting from the maximum ore weight and are primarily responsible for cracking in these intersections. Syncrude maintains high quality haul roads, which are constructed of gravel, and makes every effort to keep the shovel pit roads as smooth as possible. This problem cannot be avoided through operational practices only and must also be accounted for in the design of haul truck bodies.

May 1, 2003

By Michael Cooper, Eric Konigsmann, A. Moerman

"A paste backfill plant and underground piping distribution system was commissioned at the Brunswick Mine in June, 1998. Concentrator tailings, composed mainly of pyrite and lesser amounts of silicate minerals with a P80 of 37um (45 YO-20 pm), are pumped to the backfill plant. The backfill plant uses conventional thickening and disc filtering to dewater the solids, which are then mixed with binder in twin screw mixers. The paste is discharged through a gob hopper and one of three boreholes by gravity. Approximately 65% of the concentrator tailings will be placed underground at full production. The remaining thickened tailings will be pumped to an existing impoundment area. Application of paste technology will completely replace the use of cemented rock fill in the mine by the end of 1998.The design capacity of the paste backfill plant is a total of 360 dmtph of cemented paste through two parallel production lines. The plant is highly instrumented and controlled via a hybrid Programmable Logic Controller (PLC-5) and Fisher ProVox Distributed Control System that is in communication with the property information highway. Video and audio signals from the underground system are carried to the surface plant via a leaky feeder communications/fiber optic system.The underground distribution system consists of a network of 200mm diameter boreholes and piping. There are approximately 3.5km of boreholes and 5.5km of piping in the system. To minimize pressures, the greatest piping length from any borehole is approximately 400m with all piping being open-ended. There are no valves in the entire paste distribution system.Construction of the plant, including installation of piping to and from the plant and preparation of the underground distribution system, was completed in less than one year from the time of management approval for the $M 22.3 project."

Jan 1, 1999

By John G. Henning

The Porcupine Joint Venture operates the Dome Mine in South Porcupine, Ontario. Dome underground began production in 1910. It is the longest continuous operating gold mine in Canada, producing in excess of 15 M ounces. More than 900 underground stopes have been mined and hundreds of miles of drifts, sublevels and raises developed. Underground mining methods included shrinkage, cut and fill and longhole. Not all stopes were backfilled upon completion, particularly the longhole stopes. The Dome open pit was designed above the underground mine workings such that, as the pit is excavated, it intersects underground drifts and stopes. Potential operational problems associated with the interactions between the stopes and the pit walls may occur, necessitating pit wall redesign, ground support installation and operational rescheduling. Each intersection of the pit with the underground mine workings is closely evaluated to maintain a safe working environment and wall stability. This paper discussed how risks to pit wall stability are assessed, mitigated and monitored.

May 1, 2004

By L. C. Bird, N. T. L. Landgren, M. W. Mikhail

"Through funds made available in 1972 by the Nova Scotia Department of Mines and Energy (DME) and the federal Department of Regional Economic Expansion, a program was initiated to recover saleable coal from mine waste dumps adjacent to the existing Acadia wash plant in Stellarton, Nova Scotia.Following evaluation of these dumps in 1972, the Acadia wash plant was modified to treat high-ash material. The first production was recorded in late 1974. By the end of 1979, a total of 738,202 t of dump material had been processed, yielding a total of 205,212 t of thermal-quality coal.The successful Stellarton operation led to considering the possibility of recovering thermal coal from other dumps. Evaluation of the Westville dumps indicated total recoverable reserves of 1,346,617 t averaging 53.8OJo ash.Parameters for plant design were defined from the washability characteristics of the dump material and the results of a bulk test. Two options were proposed; one was to use the existing plant with some modifications, the other was to build a modular mobile plant that could be used at future dump sites in the province after Westville. At the 25% ash level, the potential recovery of coal from the dump was estimated at 41% yield (by weight) or 549,679 t."

Jan 1, 1981

By Mark Ferra

Flotation is used in mining to produce concentrates of copper, gold and several other valuable ores. In 2017, a copper mine near Globe, Arizona improved their rougher cells productivity using technically advanced electro-hydraulic actuators in the flotation process by enabling excellent tank pulp level process stability. The new actuators controlled the dart valve position to allow pulp to leave the cell. Tank cell pulp level can change due to feed and discharge fluctuations from neighboring tanks. When traditional pneumatic actuators are used, they have sluggish response times and overshoot due to the inherent physical property of air being compressible. Electro-hydraulic actuators have the benefit of hydraulic stiffness to deliver accurate and repeatable (0.1%) dart valve positioning. The froth layer has more opportunity time to maximize mass transfer into the launderer. The results are an increase in copper recovery by 2-4%. INTRODUCTION In 2013 there was an international flotation technical conference well attended by respected flotation specialists for both mining companies and academia. During the technical session a leading metallurgist was discussing pulp level measurement and said that when he was on the cell deck he stated, pneumatic actuators air cylinders stroking up and down. The presenter then claimed with confidence that "I listened to actuator move so the pulp level in the tank was being controlled!" No one questioned his assumption and I can assert that the audience was quite technical and not shy in their critiques of speakers. The flotation community simply believed that the existing pneumatic technology was enough with no alternative. Having a stable flotation cell pulp level is critical to effective copper recovery. Controlling pulp levels in flotation cells is a complex task that includes modulating dart valves in each cell. The use of REXA Electraulic actuators will decrease the process dead time and maintain froth height in a controlled manner, especially from pulp slurry volume fluctuations from neighboring cells. By reducing flotation cell pulp level tank height variation, a copper mine in Arizona has realized a 2-4% recovery improvement by increasing the froth transfer to the launderers in the rougher cell circuits compared to pneumatic actuators. This paper examines the benefits of using an electro-hydraulic actuator to ensure proper pulp level control and reduce the process operational cost. It will focus on actuator positioning the dart valves to maintain pulp level setpoint at a copper mine in Arizona.

Jan 1, 2019

By Arthur Grounds

Historical In the course of a paper which is necessarily limited in length, such as the present one, it is obviously impossible to describe in detail the history, development, and present position of coal preparation in Western Europe. Great Britain has been blessed with large deposits of excellent coal of nearly every type, ranging from the high-grade anthracites of South Wales, which are characterised by their very low ash and volatile con-tents, to the superb coking coals of South Wales and Durham -probably the finest in the world -with their low ash and sulphur contents, the latter constituent often well be-low l per cent. Gas coals abound in Lancashire and Yorkshire, while coals from the East Midlands, Northumberland, and Scotland are excellent for steam-raising and other industrial purposes. The excellent quality of these various coals has, in years gone by, ensured ready .sales abroad and it is not surprising, therefore; that methods of coal preparation were largely developed on the Continent in an endeavour to upgrade the inferior fuels found there, so that the prepared product could compete with British coals on the European market.

Jan 1, 1951

By Ralph Harris, Qi Xia

"Gold cyanidation rates are known to be limited by the rate of oxygen dissolution in the cyanidation tanks. The effect of solids loading on the oxygen dissolution rates is not obvious and the results of previous studies are ambiguous. The present paper presents an analysis of oxygen dissolution rates using a ""spent"" commercial gold slurry diluted to various levels of solids loading. It was found, in an 170 litre stirred tank reactor using an inverted cone sparger, that under certain high loading conditions, there was a decrease of as much as 50 %, i.e., there was a halving of the rate of oxygen dissolution as compared to that in clean water. In particular, it was observed that, due to gas flooding of the impeller, there was a drop in kLa even with an increase of gas velocity. Gas holdup reached a maximum value of only 1.7 %. The total power consumption was between 0.06- 0 .10 kw/m3 within the range of gas velocity before flooding occurred. The decrease in oxygen dissolution rate with increased solids loadings is believed to be mainly due to the increase in the apparent viscosity which reduced the turbulence and shearing effect and resulted in larger bubbles and hence reduced the reaction area a. The interrelations between solids loading, gas holdup, flow pattern, power consumption, and liquid mass transfer coefficient are discussed.IntroductionThe reactors generally used in gold cyanidation are Stirred Tank Reactors (STR). Compared with other types of reactors like fluidized bed reactor and column reactor, STR is of particular importance due to its wide application in industry. It is reported that the stirred tank reactor is used for more than 50 % of the world's chemical production (Xu and McGrath, 1996)."

Jan 1, 1997

By H. J. McQueen

Pressure welding is a solid state joining technique that depends on bringing the parts into sufficiently close contact that inter-atomic bonds are achieved. Pressing is more effective at elevated temperatures where plastic flow causes the asperities to collapse; improved application conditions are derived from hot-work research to clarify temperature and strain rate dependence of hot strength and ductility. The substructure evolution systematically studied in hot working to determine dynamic recovery or recrystallization is applied to clarifying that developed in welding. The various processes are affected differently by work-piece geometry and final shape requirements. In addition to pre-cleaning of the surfaces, the plastic flow helps disperse the remaining oxide layers as was originally exemplified in blacksmith hot forging of layered sword blades and in bellldie welding of wrought iron tubes. The presentation critically compares the utility for various materials and configurations of simple pressure, ultrasonic application, diffusion, explosive, rotary and linear friction and friction-stir processes. Diffusion bonding (primarily Ti) with light cleaning, low pressure, little distortion in protective furnace atmosphere contrasts strongly with the heavy upsetting in friction welding, or complex alloy mingling and substructure variations in friction stir joints.

Jan 1, 2011

By D. J. Thorkelson

New data indicate Wernecke Breccia-associated iron oxide copper-gold (IOCG) deposits likely formed from moderate-temperature, high-salinity, non-magmatic brines. The breccias formed in an area underlain by a sedimentary sequence that locally contained evaporites (potential source of chloride and possibly sulfur) and was thick enough to produce elevated fluid temperatures. Metals (Fe, Cu, Co, U) were probably derived from host strata, transported as chloride complexes, and precipitated due to changes in fluid temperature and pressure during brecciation. These new data suggest that the spectrum of genetic models for IOCG deposits that typically invoke formation from magmatic or hybrid magmatic-non-magmatic fluids should be expanded to include those systems that formed in a non-magmatic environment. Modifications to the definition of IOCG systems are proposed that reflect the degree of involvement of magmatic and/or non-magmatic fluids and the nature of the mineralizing environment. A division into magmatic, non-magmatic, and hybrid magmatic-non-magmatic IOCG types is suggested. Typical magmatic end-member IOCG deposits include Lightning Creek and Eloise, Australia. Hybrid magmatic-nonmagmatic IOCG examples include Ernest Henry and Olympic Dam, Australia. The Wernecke Breccia and Redbank deposits are suggested as possible representatives of non-magmatic IOCG end members. Endmember magmatic IOCG deposits have similarities to some porphyry deposits, whereas non-magmatic IOCG end members share characteristic with some sediment-hosted Cu deposits, suggesting that the range of IOCG deposits may form a link between intrusive- and sediment-related deposits

Jan 1, 2007

By Karl J. C. Harries

"6.1. INTRODUCTIONThis chapter comments on some of the more common types of agreements related to property examination and acquisition, other than the farm-in/joint venture agreement or common undertaking, which is dealt with in the next two chapters. Many of the comments made in Part IV of Chapter 4 apply equally to any such agreement. In addition, many of the comments in Chapter 8 and the examples in Volume II are most certainly relevant to many other types of agreement.6.2. RIGHTS OF FIRST REFUSAL1A right of first refusal is a right that obligates an owner to offer his property, or an interest therein, to the holder of the first right if the owner intends to sell or otherwise dispose of it. It may be triggered either by the owner wishing to offer his property for sale or by receipt of a bona fide offer to purchase his interest from an “outside” third party. The mechanics and procedures to implement a first right should be set out clearly in the agreement, and their basics are the same, whether the first right is a stand-alone document or is part of an acquisition agreement.2Rights of first refusal are common in agreements to permit some control over the disposition of an interest and there they can be a valuable provision. However, some explorationists feel that they are also a good stand-alone agreement to have while a property is being evaluated to decide whether or not it is worth optioning. The reasoning is that such an arrangement will tie up the property to allow a quick look and, if the property looks interesting, the balance of the term of the first right will give an ample exclusive period of time to negotiate with the owner and settle an acquisition agreement. In addition, the explorationist is protected by the first right if the owner decides to negotiate a deal with another party."

Jan 1, 2003

By S. Tuttle, R. Sisson

"Suncor Energy Inc. has proposed a 2.2 billion dollar expansion to the current oil sands operation, which will more than double the productive capability of the facility. As part of the application for this expansion, a comprehensive closure plan had to be developed and filed.Closure planning includes a systematic evaluation of the area to be developed, the development activities planned, the goals and objectives of the corporation in re-establishing landforms and ecosystems at the same time as running an effective operation. As early as is practical during the mine development, surface contouring is completed, soil is reconstructed, and vegetation, surface drainage and wetlands are re-established. Once active reclamation is complete and vegetation has been re-established, Suncor monitors maturation of landscapes and ecosystems to provide the submission basis for reclamation certification"

Jan 1, 1999

By Eric Schraml

Wardrop Engineering and the Placer Dome?s Campbell Mine Design Team utilized leading edge directional raise boring techniques and an innovative, remote controlled application of steel fibre reinforced shotcrete ground support to achieve improved mine ventilation and a superior, safety focused secondary emergency egress. While more standardized methods may have provided a sufficient solution to either the requirement for a ventilation raise or for a traditional escape ladder way, innovative methodology ensured both objectives were met with a single, enhanced solution. Placer Dome committed to provide a solution that minimized energy consumption, optimized air delivery and facilitated an escape way focused on minimizing the negative physiological aspects associated with mine evacuation. The project was successful in providing a new airway, returning 47 m3/s (100,000 cfm) from the 39 Level to 30 Level, minimizing risk to the raise equipping crew and providing a fully equipped escape hoist. The resulting secure escape environment provided an efficient means of evacuating personnel working at depth without necessitating a potentially dangerous exhausting climb to surface. The project has substantiated, that optimized safety focused design can be achieved without jeopardizing project economics.

May 1, 2002

By Fernando Romero Lage

"Crushing and screening theory and application has remained fairly consistent in the last 50 years. The application of such equipment is guided by varied formulaic conventions and rules that due to the entropic nature of the process, remains more an art than a science. The variability of conditions creates an environment in which trial and error becomes the principal means of process balance and control. This paper illustrates some of the theories behind the process, plus other assumptions, postulates, myths and misconceptions that exist within the crushing and screening industry.INTRODUCTIONContinuous material balance calculations are habitually performed in the design of new comminution circuits as well as in the valuation of existing circuits. A continuous material balance calculation is one in which the input rate of material is equal to the output rate for each unit functioning in the circuit. At continuous analysis, there is no accumulation or losses of material within the system, as it is when performing a discrete event analysis.In order to produce viable and manageable mine-to-mill material, whether it is ready to leach or ready to mill, we must reduce the material in a series of stages. The power demand increases as the material size decreases, as it is when folding a piece of paper successively. As with the paper, there is a crushing size limitation that is a consequence of the mineral properties such as work index, moisture, viscoelasticity, etc. Comprehensive knowledge of crushing plants in both the aggregate and the mining industries show that, after three stages of crushing, a particle size distribution originating from a blasted deposit can be reduced from an nominal maximum size of 500 mm to a nominal maximum size of 12 mm. if the last stage of crushing is set in closed circuit, the screen openings will be able to yield a smaller top size.Achieving steady and continuous material balance poses major difficulties as crusher lose their settings, screens blind or peg, and material characteristics change geographically or seasonally. Overloading conditions in crushers and screens are nothing but counterproductive, and the net losses of an unbalanced circuit can be overlooked when mining operators are paying a lot more attention to the evermore complex systems downstream.It is not simply the crushing of the mineral but achieving the right size for the downstream milling process that will yield the maximum amount of energy savings."

Jan 1, 2010

By H. Warren Newcomen

The southwest wall of the Lornex Pit at the Highland Valley Copper mine has been experiencing slope displacements since 1978. Measures to manage the displacements on previous pushbacks have included stepping out, scheduling pushbacks to unload the crest of unstable areas, slope dewatering and mining with intensive slope monitoring. The final pushback on this wall is currently being mined and substantial modifications to the slope geometry could prove to be uneconomic. As a result, a campaign of surface water collection and diversion, horizontal drainhole drilling and deep well drilling is currently underway to maintain an acceptable degree of stability to the end of mine life. The various factors contributing to instability, including engineering geologic controls, rock mass strength, and surface and groundwater hydrology are presented. Movement trends, displacement magnitudes and stability analyses results are also discussed.

May 1, 2002

By S. Mostaghel, V. Hernandez, S. Ge

"The automotive industry is under a constant pressure to reduce the weight of vehicles in order to reduce emissions and improve fuel efficiency. As such, there is an ever-growing demand for high strength and high ductility steel grades to meet the need for lightweight automotive components. Over the past decade, the production and application of 2nd and 3rd generation Advanced High Strength Steels (AHSS) as a lightweight material in automobiles has gained significant popularity due to their exceptional mechanical properties. However, the production cost of these high manganese steel remains high, partially due to the need of large amounts of ferromanganese as alloying material in standard steelmaking processes.The current study introduces a new and cost-effective technology for the production of medium- and high-manganese steels, where self-fluxed micro-pellets of manganese ore will be used as the source of manganese that can be injected into the steel bath. Prior to injection, these pellets are subjected to a pre-reduction process using a mixture of H2 and CO gases, where partial metallization of iron and manganese will occur. Direct injection of the pre-reduced micro-pellets provides less volatilization/emission and higher recovery of manganese, and is capable of producing AHSS with 6–18 wt% Mn.INTRODUCTIONAutomakers are constantly searching for lighter, stronger and cheaper materials in an effort to create safer and more fuel efficient vehicles. The introduction of aluminum alloys and polymer composite materials for automotive applications has been carving into what is traditionally one of the most profitable markets of the iron and steel business. The steel industry responded with Advanced High Strength Steel (AHSS)—a family of manganese containing steels which exhibit exceptional strength and ductility."

Jan 1, 2016