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By W. R. Middagh, R. M. Garvey

"Phosphate rock is shipped by boat from Florida to Vancouver, B.C., where it is unloaded and stored in a 50,000-ton silo. It is shipped from Vancouver in 100-ton hopper cars in 80-car trains to Fort Saskatchewan. Both the ship and the hopper cars are on a back-haul with potash. The rock cars are unloaded at Fort Saskatchewan at a rate of approximately 4 cars per hour. The rock is stored in three concrete silos, 40 ft in diameter by 110 ft high, which hold 18,000 tons of recoverable rock with 2,000 tons dead space. The rock is reclaimed from the silos by gravity and fed to the phosphoric acid plant by remotely operated conveying equipment.Problems encountered in the operation include scheduling the rock shipments, contamination of the rock with potash, and handling the 80-car trains both in Vancouver and Fort Saskatchewan."

Jan 1, 1968

By R. Salimi

Tricalcium aluminate hexahydrate (TCA) is used as filter-aid for security filtration in the Bayer alumina process. TCA is typically produced on-site by mixing Bayer liquor with slaked lime. Specific properties are required from the TCA to ensure adequate filter throughput, lifetime and importantly effective reduction of solid/colloidal impurities from the solution. The effect of reaction time on morphology and particle size distribution of tricalcium aluminate was studied for a batch experiment at simulated process conditions. It was found that reaction time plays a critical role on the morphology, crystal structure (diameter and crystallinity) and particle size distribution. In the early stages of the reaction, nucleation dominates the crystallization process followed by growth dominated by agglomeration up to a mean particle size of 10 µm. The particle morphology shifted from an irregular shape to more spherical throughout the course of the reaction.

Jan 1, 2014

By G. Langlands

"R. Tenbergen Is this flotation machine suitable in the flotation ofInco ball mill discharges where we have a coarse feed at 60% solids?Reply Experience has shown that there is not a significant increase in the wear life of these machines when handling coarse material (8 mesh) at 60% solids. A common practice in Europe is shut down on the week-ends.The material is allowed to settle and on start-up an injectic of air for 15 seconds is sufficient prior to start-up. At,mining we put our unit in the middle of a bank of 44 cells and in order to ensure severe sanding we shut the aker cell down while the remaining cells kept running. After 20-25 seconds of air the cell started without trouble.P. Mahant Is there a build-up inside the impellor shaft housing? Falconbrige Ltd.Reply There is no sand build-up but rather a scale build-up which due to a flexing action frees itself periodically. Part of the design of the machine permits a water injection into the shaft housing to free any build-up. This is done in Europe during the week-end shut down."

Jan 1, 1984

By H. Kuboyama

The synergistic effects of polymer additives such as gelatin and polyethylene glycol) (PEG) and Cl- on Cu electrodeposition have been investigated by measuring the polarization curves for Cu deposition, by rotating ring-disk electrode technique and by AC impedance measurements. The cathode potential for Cu deposition was greatly polarized in solutions containing both Cl- and gelatin or PEG, showing evident synergistic effect of polymer additives and Cl- on Cu deposition. The cathode potential was shifted to the less noble direction with increasing the concentration of Cl- in solutions containing polymer additives and showed the maximum polarization at Cl- concentration range between 0.1 and 1 mmol/L. The rotating ring-disk electrode technique revealed that Cu deposition in solutions containing small amounts of Cl- proceeded with initial formation of adsorbed intermediate CuClad. The Cole-Cole plots obtained by AC impedance techniques suggest that the reduction of CuClad is suppressed by polymer additives. The morphology of Cu deposited from solutions containing both PEG and Cl- showed the compacted surface composed of smaller grains due to an increase in the overpotential for Cu deposition.

Jan 1, 2007

By Michel Gamache

This paper describes a system that manages and assigns vehicles in real-time in an underground mine. Each dispatching decision takes into account the traffic on the road segments of the mine network, whether bi-directional or unidirectional, and ensures that each LHD (Load-Haul-Dump Vehicle) arrives in the right orientation at loading and dumping points. Such systems can be used for two main purposes: 1) as a strategic planning tool and 2) as a real-time managing and optimising system for operations. Using a simulator in conjunction with the fleet management system, it is possible to accurately estimate the impact on productivity of decisions such as the development of waiting areas (bays, sidings), or the addition (elimination) of vehicles to the fleet in operation. Moreover, when used in for real-time dispatching, routing and scheduling of vehicles, the system can optimise production with respect to various assignment criteria such as minimising the cycle time or minimising the deviation from an optimal production plan. Dispatching, routing, and scheduling are handled simultaneously, taking into account the mine status, operational constraints, and all available information.

May 1, 2001

By Shoma Sinha, Nirmal K. Sinha

Deformation in a material at any temperature is known to consist of two major components - a reversible (elastic) part and an irreversible part (often called plastic). What is not universally known is the fact that at high temperatures greater than about 0.4Tm, where Tm, is the melting point in Kelvin, the reversible part includes not only elastic but also a delayed elastic (recoverable but time dependent) component. A very simple computational model is presented here for a constant-strain stress relaxation test (SRT) on the basis of a three-component constant-stress rheological equation derived from strain relaxation and recovery test (SRRT) data. It is shown that the rapid stress reduction during the early periods of relaxation when the stresses are high is governed primarily by delayed elasticity irrespective of the imposed strain level. This is in contradiction to the popular concept prevailing today. The asymptotic approach to a quasi-stable stress rate at longer times and lower stresses is, however, controlled by viscous flow (power-law creep). The validity of the theory is examined by comparing the predictions with experimental results obtained for a titanium-base alloy Ti-6246 at 0.45Tm.

Jan 1, 2004

By C E. Gordon Brown

Aircraft utilization, weather and cost data are given for three separate projects north of the sixtieth parallel in the Northwest Territories and the Yukon Territory. These operations, carried out by helicopter-equipped geological and prospecting parties, have cost $24 to $30 per square mile, depending principally on the distance from the base. They provide adequate surface exploration of areas with 40 to 50 per cent rock outcrop. A good one-inch-to-one-mile geological map can be made. T HE exploration of the Canadian northland has been given increasing attention by the mining industry during recent years. In many cases, the initial problem is to make an adequate reconnaissance of a large area where existing geological information is meagre. The Geological Survey of Canada pioneered the use of helicopter-equipped geological parties for mapping at a scale of eight miles to the inch.

Jan 1, 1964

By Martin Wacker

Cameco Corporation, on behalf of a joint venture, is preparing surface and underground facilities at their northern Saskatchewan property in preparation for the future operation of a high-grade uranium mine. The Cigar Lake orebody is situated about 430 metres below surface at the unconformity between metamorphic basement rocks and flat lying sandstone. Major technical factors influencing the mining method selection include ground stability, control of ground water, radiation exposure and ore handling and storage. A decade-long test mine program resulted in the selection and validation of ?jet boring? a non-entry mining method. Cigar Lake?s jet boring mining method involves several major steps; artificial ground freezing of the orebody and surrounding rock, TBM (tunnel boring) type development of access crosscuts below the orebody, installation of cased pilot holes upwards through the ore, and ore extraction using a rotating high pressure water jet within the pilot holes. The resulting cavities are surveyed and backfilled with concrete. The ore slurry will be processed underground and pumped to surface. This paper discusses the jet boring mining method in general terms and includes highlights of the Cigar Lake test mine program completed in 2000.

Apr 1, 2005

By A. B. Parsons, P. G. Howes

"This article discusses how recent changes in the federal and Quebec .income tax laws have contributed to an improved investment climate for mineral exploration in the Province of Quebec. Individual investors who are resident in Quebec and who are in the highest tax bracket (1984-60.4% marginal rate) may obtain tax benefits that result in only nine cents of each invested dollar being at risk.IntroductionIn a recent submission by the Mining Association of Canada to the Royal Commission on the Economic Union, it was stated that the mining industry ""is no longer discovering and opening new mines at rates sufficient to offset the depletion of existing orebodies and to maintain pre sent output"". With world metal prices still in a depressed state following the prolonged 1981-82 recession, moreover, the continuing success of Canadian mining in world markets will depend on this country's ability to compete in a new environment characterized by subsidized Third World production . For the most part, this new competitive environment will encourage the development of cost-efficient mines that are better equipped to withstand the troughs and valleys of international metals prices."

Jan 1, 1984

By Stavros A. Argyropoulos, Radhakrishna Valiveti, Bernard Closset

"The use of microprocessors in metallurgy is currently increasing at a very fast rate. A large number of companies are offering systems ""off the shelf"" which are aimed at the data acquisition and process control market. There are two main drawbacks to these systems: first, they are usually quite expensive, and second, they are not completely compatible with the target metallurgical application. An alternative is to develop a microcomputer-based system "" in lab "".A dedicated microcomputer system has proved to be very useful in many metallurgical research applications(1,2)). However, in this system the analog input signals had to be transferred over long distances , and significant noise was introduced despite the use of shielded cables. In order to overcome this problem a network of low pass-filter s was designed and built. The usage of the abovementioned system brought the need to digitize the analog signals in-situ and transfer the digital signals, which are much less susceptible to noise over very long distances. This distinctly different design philosophy has become a reality with the evolution of microprocessor technology over the last few years. This design philosophy is utilized in this development."

Jan 1, 1984

By G. R. Baiden

This paper discusses the application of Load-Haul-Dump (LHD) machine teleoperation in combination with a guidance system for single operator control of multiple IJIDs. A system accomplishing these goals has been tested at Copper Cliff North Mine of Inco Limited. This development uses a high-speed, high-capacity production network to teleoperate an LHD during loading and dumping by using 3D video and radio remote control. Following loading, the operator dispatches the LHD using an automatic guidance system to traverse the drifts to the orepass. Remote dumping is done at the ore pass and then the machine returns to repeat the procedure. This has significant productivity gains and improvements in safety. Productivity is improved because operators are involved only in the loading and dumping part of the process. This frees the operators to utilize their time more effectively, loading or dumping a particular machine, while other machines with guidance systems continue to work travelling and/or automatically dumping ore in the ore passes. Safety is improved as the operator is located on a remote control station. Automatic dumping will be incorporated as a future development.

Jan 1, 1994

By Robert D. Brown

"All ten Canadian provinces have now tabled their 1981 /82 budgets . Only the provinces of Ontario, Quebec and British Columbia made more than minor modifications to their tax structures, with both Ontario and Quebec imposing major tax increases. In the past year, the federal budget was also released in the spring. Not so this year: we have that to look forward to in the fall!This month, Tax Notes presents a brief summary of the more significant tax changes introduced at the provinciallevels in the last months.Summary of provincial tax rate changesThe tax changes in this year's provincial budgets were both up and down- but there were far more tax increases than tax cuts.At the corporate tax level, two provinces, New Brunswick and British Columbia, increased their general corporate income tax rate; the former by two percentage points and the latter by one percentage point. Quebec, rather unexpectedly, sharply cut its corporate tax rate on business income, but increased some of its other business taxes at the same time. British Columbia reduced its corporate tax rate on small business income by two percentage points and Saskatchewan by one percentage point."

Jan 1, 1981

By Jae-Chun Lee, Rajiv Ranjan Srivastava, Min-seuk Kim, Byung-Su Kim

Recycling of spent hydrotreating catalysts (HTC) can potentially contribute towards the sustainable extraction of metal values. Treating such materials by hydrometallurgical methods to separate metals from the leach liquor of either acid/alkali media is a major step. In the present study, separation of molybdenum from HCl leach liquor of spent NiMo type HTC has been investigated by applying solvent extraction using Cyanex-923. For this, the chloride solution containing 973 mg/L Mo, 254 mg/L Ni and 1634 mg/L Al was taken as the aqueous feed. The parameters including contact time, concentration of the extractant, acid and chloride, and phase ratio were varied to investigate their effect on the extraction efficiency. The McCabe-Thiele plot suggests that > 99% Mo-loading using a 2-stage extraction process. From the molybdenum depleted solution, nickel was selectively extracted by Cyanex-301 leaving Al in the raffinate.

Jan 1, 2014

By Alan F. Stewart, Frederic B. Claridge, Robert S. Nichols

"In recent years, an increasing number of mines in mountainous terrain have examined the possibility of placing mine waste rock into stream valleys. Pressure to utilize stream valleys as a primary location for waste disposal has increased at many of the mines currently under development or expansion. As the number of environmentally and economically ideal wastedumping sites is limited, consideration must be given to utilization of stream valleys. This raises concerns about maintaining water quality in streams passing through or beneath the dumps and potential detrimental effects to dump stability. Commonly, the flows in the streams tend to be flashy, reflecting localized intense storms and rapid runoff in steep-sided slopes within the watershed. These conditions pertain particularly to British Columbia, which is characterized by mountainous terrain and periodically intense precipitation events.The method of conveying flow through a waste dump depends on a number of geotechnical and hydrological factors, including the size, durability and transmissivity of the rock and the design stream flood flow. This paper describes the approach to the design of waste dumps in stream valfeys developed at several mines in British Columbia."

Jan 1, 1986

By G Anders

The effectiveness of two types of powder used in long-wall slashing was compared. The evaluation of the results can serve as a good example of how the application of statistical methods to underground test data can help to minimize the number of tests to be carried out. The conclusions are stated concisely, including a definite assessment of the reliability of the tests. Introduction AN assignment at the Algom Nordic mine called for a performance comparison between 70 per cent Cilgel B and 75 per cent Dygel in longwall stope slashing, particularly taking into account, in both cases, the build-up of bootlegs as dependent on hole deviation. Stopes were usually 8 to 10 ft. high and inclined at about 17 degrees. Starting from a raise, they were widened by consecutive longwall slashes to 60 ft., and, al-lowing for drift pillars, were approximately 300 ft. in length along the incline.

Jan 1, 1964

By Brian Hart, Roger St. C. Smart, James Francis, Mark Biesinger

"There are a number of challenges involved with the surface analyses of different mineral phases from process streams in a flotation facility. The first of course is to collect samples that are representative of the process and to ensure that they remain in a pristine condition prior to introduction into the instrument. In mineral processing, sample collection from the different streams is done on site and preservation involves simply removing oxygen from the sample by bubbling nitrogen or argon gas through the sample and snap freezing with dry ice.The second challenge in studying the surface chemistry of specific minerals is to find reliable methods of mineral phase recognition. In surface analysis of mineral particles confident mineral selection can be difficult with many multi-metal minerals (e.g. chalcopyrite, pyrite, sphalerite) and with precipitated, adsorbed, reacted and contaminant species in the outermost molecular layers.In this paper we show that principal components analysis (PCA) of ToF-SIMS data provides improvement in phase recognition, particle selection and associated variations in surface species. We will demonstrate, with specific examples, that this technique can be utilized to differentiate surface chemical factors promoting (hydrophobic species) or inhibiting (hydrophilic species) flotation.Species recognition based on the PCA method in a study of Cu transfer between chalcopyrite, pyrite and sphalerite mineral mixture clearly identified a statistical difference in copper intensities between the sphalerite and pyrite phases. A similar ToF-SIMS/PCA based study applied to concentrate and tails samples collected from the Inco Matte Concentrator demonstrated extensive CuOH and NiOH transfer between the chalcocite and heazlewoodite minerals. The statistical analysis has been able to confirm some mechanisms and deny others proposed to control recovery and selectivity giving more focus on the control factors.The ToF-SIMS PCA statistical analysis has elucidated differences in surface chemistries which illustrate the discriminating depressant action of adherent aluminosilicate (gangue) fine particles and adsorbed ions on the surface of sphalerite grains. In the flotation test concentrates, HIC conditioning resulted in the removal of these gangue fines thereby improving surface collector attachment efficiency, promoting a greater recovery of sphalerite."

Jan 1, 2007

By Vanessa C. Koppe

During ore body modeling normally additional samples are required to improve resources evaluation and mining planning. At this stage one rises the question about where additional samples should be located. Regular sampling pattern seems to be a reasonable choice, since all the regions within the deposit receive the same number of samples without a clear clustering. Nevertheless, values for certain attributes (grades for instance) from a mineral deposits may behave more erratic in some regions than others. Consequently, by adding samples to these regions could bring more benefit for reducing the uncertainty related to a transfer function such as Net Present Value (NPV), instead of adding samples to location of low grade uncertainty. Thus, for a given number of additional data, the test of a regular pattern and a pattern which add samples on areas of high uncertainty of the attribute of interest is worth. This paper presents an algorithm that allows the construction of these two patterns, automatically, on a software commonly used in the mining industry. The algorithm leads to a fast analysis on the efficiency of the two patterns in reducing the uncertainty associated with a transfer function.

Oct 1, 2009

By K. Forsberg, A. Rasmuson, R. Rodriguez Varela, J. Martinez De La Cruz

"This study analyzes the separation of rare earth elements by means of a supported liquid membrane (SLM) with the final objective of recovering REE from an apatite concentrate (Alemrajabi, Forsberg, & Rasmuson, 2015; Mohammadi, Forsberg, Martinez de la Cruz, & Rasmuson, 2015). In this study, the feed phase consists of an aqueous phase containing REE, the membrane phase contains the organic solvent and carrier (D2EHPA and EHEHPA), and the stripping phase is a hydrochloric acid solution. An evaluation of mass fluxes, separation efficiency, and membrane performance is conducted. In order to analyze the suitability of liquid membranes in the extraction of REE, a deeper insight into the mechanisms causing instability is needed. In this study, surface tension is considered as the key factor of Marangoni instabilities and spontaneous emulsification.INTRODUCTIONThe demand of REE and their compounds has increased considerably due to their special physicochemical features that make them crucial elements for numerous high-tech applications, including wind turbines, hybrid cars, mobile phones, and defense technologies. They are also extensively utilized in traditional industries such as nuclear energy, petroleum, metallurgy, agriculture, and textiles (Xie, Zhang, Dreisinger, & Dyole, 2014; Zhang, Wu, Bian, & Zeng, 2014).Solvent extraction is widely used for the separation of REE (Xie et al., 2014; Zhao, Huo, Pan, Li, & Liu, 2014). Di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHEHPA) are two of the most effective extractants for the separation of rare earth elements among organophosphorus extractants (Gupta & Krishnamurthy, 2005). However, the difficulty in stripping loaded D2EHPA extractant, especially for heavy REE, has limited its utilization. Yttrium can be stripped at lower acidities in EHEHPA systems compared to D2EHPA systems (Gupta et al., 2005), but the extraction efficiency is lower. Conventional solvent extraction by mixer-settlers is restricted by its large solvent inventory and loading limits, and suffers from phase disengagement, emulsification, loss of solvent, and flooding problems (Swain, Jeong, Lee, & Lee, 2007). In this context, supported liquid membranes (SLMs) present a potential alternative due to their advantages, being low solvent inventory, process simplicity, low energy and operational costs, great enrichment ratio, and combination of extraction and stripping into one single step. A SLM is a system in which two aqueous phases are separated by an organic liquid membrane suspended in the pores of a porous support by capillary forces. One of the aqueous phases is the feed solution with the solute and the other is the stripping or receiving solution. The solute diffuses through the liquid membrane and then is extracted into the stripping solution (Kislik, 2010)."

Jan 1, 2016

By D. Warkentin, M. Tomlinson, A. Nacu

"This study focuses on comparing the “blinding” effectiveness of various organic additives as part of a general review of using organic additives to mitigate preg-robbing and improve gold recovery during cyanide leaching of carbonaceous gold ores. The laboratory results compared the impact of various organic additives on the prevention of gold adsorption using both activated carbon and ore samples containing carbonaceous matter, generally referred to as total carbonaceous matter (TCM). Although several organic reagents were found to have a significant blinding effect on activated carbon, these results did not translate into increased gold leaching efficiencies with actual ore samples.INTRODUCTION Preg-robbing refractory ores, which contain carbonaceous matter, have been problematic in cyanide plants for many years. In industry, preg-robbing by carbonaceous matter may be mitigated using various techniques including flotation, to remove the carbonaceous matter; addition of blinding agents, to passivate the carbon surface and prevent adsorption of gold cyanide complex; roasting, to partially or fully destroy the carbonaceous matter; chemical oxidation (Abotsi & Osseo-Asare, 1986); pressure oxidation; or microbial deactivation (Dunne, Staunton, & Afewu, 2013). Carbon-in-Leach and Resin-in-Leach are also used as process alternatives in which activated carbon or resins are used to compete with the carbonaceous matter for gold cyanide adsorption. For highly preg-robbing ores, thiosulphate leaching may be considered as an alternative to conventional cyanide chemistry (Baláz, et al., 2000). Natural carbonaceous matter is composed mainly of hydrocarbons, organic acids, and graphitic/amorphous elemental carbon. Natural elemental carbon that behaves as activated carbon is considered to be the main reason for preg-robbing, although the true nature of this phenomenon is not fully understood (Tan, Feng, Lukey, & van Deventer, 2005). In general, the hydrocarbon fraction is assumed to have negligible interaction with gold, while organic acids, such as humic acids, may form complexes with gold, inhibiting its extraction in cyanide solutions. Organic reagents have been used for blinding carbonaceous matter in gold ores prior to cyanidation. Abotsi & Osseo-Asare (1987) tested various organic compounds, with two possible effects in mind. First, the organic compounds were expected to adsorb onto the surface of the solids as anionic/cationic species; the resulting electrostatic interactions between the Au(CN)2- anion and the negatively/positively charged surface would inhibit/enhance the gold uptake. Second, the organic reagents were expected to coat the surface of the carbonaceous component in the ore, limiting the available adsorption sites and reducing gold losses. Optimal reagent dosage depends on ore mineralogy, maturity and surface area of the carbo"

Jan 1, 2019

By G. Morin, G. Marin, M. C. Parr, J. Carignan

"Investment casting offers many advantages for the near net shape production of complex geometries, however, molten titanium reacts with most of the refractories used in investment casting shelling systems, which leads to the formation of an oxygen contaminated surface layer. This layer, called alpha case, is 0.1 to 0.6 millimeters in thickness according to the casting section size and must be removed either by mechanical or chemical milling processes. Alpha case removal processes affect casting tolerances and may contaminate the part intended for medical applications (e.g. embedding of abrasive grit media in the alloy). A shelling system based on an yttria prime slurry has been developed and was found to almost suppress the mold metal reaction. Yttria is an expensive refractory, but slurry life was found acceptable for small castings using a closed container and flow coating process instead of conventional pattern dipping. Alpha case depth has been determined for Ti6Al4V by metallographic techniques and microhardness measurements on different step block casting cross sections. Alumina and yttria second prime stuccos were evaluated in this study. The shelling system minimizes finishing operations in the production of casting for medical applications.INTRODUCTIONTitanium investment castings have been in the commercial market since the beginning of the titanium era in the mid 50’s. Investment casting is a cost effective way to produce complex parts for medical, aerospace and chemical processes applications. Investment casting of titanium is difficult due to the high reactivity of titanium with air and refractories used for shell mold building especially for the face coat. Melting is done under vacuum and no shelling system has been proven effective to suppress the mold-metal reaction yet. The main issue with the mold-metal reaction is the formation of an oxygen enriched zone at the surface of the castings named alpha case (Frueh et al., 1997; Kim, 2002; Saha, 1986). The alpha case is brittle, reduce the fatigue life in service of the parts and must be removed by chemical milling.For industrial purposes, calcia partially stabilized zirconia based slurries have become widely used in titanium investment casting for primary coats due to a combination of limited metal shell reaction. Calcia stabilized zirconia slurries have an acceptable shelf life and offer an interesting production window. Our experience shows that a resulting alpha case depth is 280 micrometers for a casting section of 6.35 mm in thickness is typical with such a shelling system (Morin, 2013)."

Jan 1, 2016