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By A. Desbiens, M. Maldonado, R. del Villar, Aguilera. R.

This work details the application of a multiple model approach to estimate frother concentration in flotation processes. The methodology consists of identifying a set of linear dynamic models representing the effect of gas rate on the collection-zone gas holdup at different known frother concentrations (calibration step). An adaptive law is then obtained using Bayes' rule to evaluate the conditional probability that each model represents the observed system behavior. In this way, a frother concentration estimate is calculated as a weighted sum of model probabilities and their associated (known) frother concentrations. Experimental results conducted in a two-phase system using Dowfroth250C are promising. Modeling and analysis for MIBC frother are also provided.

Jan 1, 2009

"Canada Centre for Mineral and Energy Technology (CANMET)Natural Resources CanadaMining and Mineral Sciences LaboratoriesA. Address and Contact Information555 Booth StreetOttawa, Ontario, Canada, KIA OGlWebsite: http://www.nrcan.gc.ca/Contact: Philippe Dauphin, Manager, Business DevelopmentTel.: (613) 947-0798Fax: (613) 947-0984E-mail: pdauphin@NRCan.gc.caB. Type and Size of FacilityScope of facilitiesCrushing from minus 4 in. to 10 mesh; grinding - rod, ball, vibration, SAG and impact mills; classification- screening, cycloning, mechanical, hydraulic and dry centrifugal classifiers; froth flotation - automated, column, and frothless flotation; gravity separation- wet and dry; magnetic separation - high gradient, high and low intensity, wet and dry; electrostatic separation; heavy-media separation; calcining; cyanidation; thickening; filtration; drying - fluid bed and freeze drying; pelletizing; microwave.SpecialtiesMineral beneficiation research and development; flotation of sulphides - flowsheet improvement, selectivity, reagent selection; novel flotation techniques; analysis of thiosalts formation; use of mineral processing techniques for recycling.Specialized equipmentHigh gradient magnetic separation, Denver XRF on-stream analyzer, automated flotation cell.Complementary support servicesElectron microprobe; SEM; STEM; X-ray diffraction; particle size analyzer; mineralogical and analytical chemistry services; physical chemistry; hydrometallurgy; pyrometallurgy; engineering and economic evaluation; mechanical shops; technical information services and library integrated with the National Library System of the National Research Council."

Jan 1, 2000

By S. Esfahani, M. Barati

Heat recovery from blast furnace slags is often contradicted by another requirement, to generate amorphous slag for its use in cement production. As both the rate and extent of heat recovery and slag structure are determined by its cooling rate, a relation between the crystallization kinetics and the cooling conditions is highly desired. In this study, slags with different basicities were studied during non-isothermal cooling. Their continuous cooling transformation (CCT) diagram were plotted and compared with each other. Then, a mathematical model was developed that predicts the amount of crystallization during cooling. The results were validated by experiments performed by Single Hot Thermocouple Technique and image analysis. A second mathematical model that calculates temperature history of slag during its cooling was coupled with the above model, to allow optimizing the slag/air ratio for both heat recovery and slag glass content.

Jan 1, 2015

By Joseph Daniels

When Dame Nature shook her horn of plenty and distributed her bounties over the face of the earth, she blessed the Pacific coast with many riches, but with these she added many offsetting disadvantages or handicaps, designed, no doubt, to effect a proper balance between wealth and economy. Nowhere is the application of the law of compensation more aptly illustrated than in the matter of fuel and power resources. A glance at the map of the Pacific northwest will show that west of the Coast Range batholith we are bounteously supplied with coal, with timber, with water power, and with tributary resources of oil from California. Alaska, British Columbia, Washington, all contain large resources of coal; Oregon and California to a lesser degree, but, compensating the golden state for its deficiency in this respect, oil was placed in the treasure ,chest. Timber, of wide variety and in lavish quantity, covers the forests from tidewater to mountain slope, and within this protected watershed area flow streams which give the Pacific coast states the largest single share of the potential water-power resources of the country. Something over 40 per cent. of the total estimated horsepower of the United States is to be found in the Pacific states, and British Columbia has 15 per cent. of the total for Canada; but of this total less than 10 per cent. has been developed.

Jan 1, 1924

By Robert T. McKnight

"Traditional techniques for valuing resource projects companies have been primarily based on discounted cashflow methods (DCF) or by comparison to similar projects with an apparent market capitalization. Many resource projects are really forms of options to invest rather than a future cashflow stream. Employing the DCF method to value a resource project which is really an option to invest, can dramatically underestimate the real value of the project. The analytical tools required to evaluate options, while more complicated than the usual spreadsheets used for DCF, are becoming more easily available and usable by managers. This paper will discuss the background of options valuation and some of the tools which will make it easier for managers to estimate the value of projects and companies which have significant real option values.ResumeBob McKnight is a graduate of the University of British Columbia in Geological Engineering, supplemented by an MBA from Simon Fraser University. Following several years in the oil patch with Cities Service and Brascan, Bob returned to Vancouver in 1979 to work for Wright Engineers. He subsequently went on to work for Cassiar Mining, Getty Resources and Endeavour Financial before joining Pincock Allen & Holt Ltd. in 1998. His experience ranges from exploration to feasibility studies, financial evaluations of mining and oil & gas projects, due diligence, project finance, valuations and mergers and acquisitions. He has extensive international mining experience pertaining to such countries as Chile, Mexico, Uruguay, Thailand, Indonesia, Angola, Papua New Guinea, Kazakhstan.What are Options?Options have been around for centuries. They were familiar to Roman and Phoenician traders who were shipping cargoes from Mediterranean seaports. In the financial world, options are types of contracts that generally include the right, but not the obligation, to buy or sell a share, currency or commodity. The underlying commodity price or share price changes are assumed to be lognormally distributed. In this context, options are of two general types, ""call"" options and ""put"" options. Call options have the characteristic of having the right to buy a tradable commodity or currency at a predetermined price for a specified period of time. For the owner of call options, they become more valuable as the price of the underlying commodity increases. For the seller of call options, these options become an increasing liability as commodity prices rise, since there is the obligation to sell the commodity at a predetermined (perhaps lower-than-market) price. This characteristic of call options recently became high profile with the sharp rise in gold prices last year. The value of gold call options sold by certain producers increased their associated liabilities to the point where margin calls were made."

Jan 1, 2003

By J. D. Robertson

An in situ water sampling device has been developed to measure biologically-available or “labile” metals in natural waters and effluents. The active mechanism involves the use of a polyacrylamide gel layer to quantitatively control metal transfer to a trace-metal-adsorbing, gel-imbedded resin. Because the resin only adsorbs free metal ions (the gel sampler methodology is a kinetic speciation technique), and because metal bioavailability is related to the free-ion activity, the device provides a direct measure of the biological-availability of metals in the environment sampled. The prototype consists of a layer of ion-permeable polyacrylamide gel which separates the solution to be sampled from an ion exchange resin. Because approximately 90% of the polyacrylamide gel is water, mass transport through the gel is diffusion-controlled, and is therefore well defined. Metal ions are rapidly bound by the resin, creating a steep concentration gradient in the gel. The amount of labile trace metal that accumulates on the resin can be related directly to the concentration of the metal in solution, the exposure time and the molecular diffusion coefficient of the labile species. In addition, the passive nature of this device affords it the potential to address many of the limitations presented by conventional sampling methods, such as sample contamination introduced during collection or filtration and changes in trace metal speciation prior to analysis. Laboratory studies and limited field trials indicate that the sampler behaves as anticipated and illustrate that biologically- available metal concentrations in many environments are a small fraction of the total concentrations and often significantly less than the dissolved concentration. The implications of this on regulatory criteria are discussed. Additional field trials and correlation with bioassays are currently underway.

Jan 1, 2000

By I. Stefanou, J. Sulem

"In the last thirty years, the study of earthquake mechanisms has emphasized the major role of rock friction. Earthquakes appear to be the result of a frictional instability and occur by sudden slippage along a pre-existing fault or a plate interface. Multiphysics couplings play a major role in earthquake nucleation and seismic slip. The effect of shear heating and thermal pressurization may be of prime importance in the control of the stability of shear deformation inside the slipping zone. Other mechanisms in relation with thermal decomposition of minerals affect the pore pressure and the temperature evolution of the system, and can play a significant role in the extreme strain localization observed in field. The actual width of the localized zone is a key parameter for understanding fault weakening mechanisms. On the basis of field observations, laboratory experiments and recent advanced modeling, these phenomena are analyzed and discussed in order to bring some new insights in the understanding of earthquakes nucleation.INTRODUCTIONIn the last thirty years, the study of earthquake mechanisms has emphasized the major role of rock friction. Earthquakes appear to be the result of a frictional instability and occur by sudden slippage along a pre-existing fault or a plate interface (Scholz, 1998; Sykes, 1978). The conceptual model of spring slider system is commonly used to represent the interaction between an elastic crustal block and a fault zone. Stick-slip instability is possible if the softening rate of the shear resistance of the fault zone is high enough as compared to the stiffness of the crustal block. Therefore, weakening mechanisms that can explain how the frictional resistance of a fault decreases with slip and/or slip rate is of prime importance to understand how an earthquake nucleates. In recent years, several drilling programs in active faults (e.g. the Nojima fault in Japan, Boullier, 2011; the Aigion Fault in Greece, Cornet et al. 2004, the Chelungpu fault in Taiwan, Ma et al. 2006, and the San Andreas fault in the U.S.A. Ellsworth et al. 2000) as well as high velocity friction experiments (e.g. Tanikawa et al 2012a; Tanikawa et al. 2012b) have highlighted the physico-chemical processes involved in the nucleation of seismic slip (see for the example the review paper of Niemeijer et al. 2012)."

Jan 1, 2015

By Nancy C. Mohn

?Even though the age of many existing coal units exceeds 30 years, these units continue to perform with excellent reliability and at a competitive cost with other fossil fuel units. ?NERC data shows a consistent increase in availability for all utility coal generation ?With the opening of power markets, the challenge for coal is to produce competitive electricity while meeting increasingly stringent, and costly environmental limits. ?During the 60s and 70s, subcritical steam power plants dominated the market. The emphasis was on scale-up to larger MW size units. ?In the last decade, we have seen interest in a broader set of technologies with new drivers: ?Fluidized bed technology was developed to respond to increased environmental requirements, particularly with lower quality fuels ?Supercritical pressure units have gained interest for both fuel cost savings and reduced emissions due to higher efficiency.

May 1, 2001

By Frank D. Shepherd

THE Gunnar Gold Mines property is on the west shore of Beresford lake, in the Rice Lake mining division, southeastern Manitoba. Gold was first discovered in place in the Rice-Beresford Lakes area in 1911 on the Gabrielle claim, now included in the San Antonio Mines property at Rice lake. Following an eastward trend of favourable prospecting ground, promising showings were next staked in the vicinity of Long lake during the years 1915 and 1916. At that time, William Walton and associates, among them Gilbert LaBine, staked the Eldorado vein, north of Long lake, and Eldorado Gold Mines, Limited, was formed to develop the property a Company that, later, was to become widely known through successful operation of its radium-silver mine at Great Bear lake, Northwest Territories. Continuing eastward from Long lake, Walton and his partners, Gunnar Berg, Leo Seaberg, and Wm. Quesnel, staked claims during the years 1920-24 in the vicinity of Beresford lake which, later, were to become incorporated into the Gunnar Gold Mines property. The presence of gold-bearing quartz on these claims had been known from the time they were staked, but an opportunity to consolidate them into a group was not forth-coming until early in the year 1933. Although promising gold showings had been disclosed during the performance of assessment work on individual claims, no continuous mineralization having mine-making possibilities was discovered until after the consolidation of the entire group. From this stage onward, progress was rapid. Active exploration was begun on August 1st, 1933, and late in October James Houston reported favourably on the property. On October 27th, Gunnar Gold Mines, Limited, was incorporated in the Province of Ontario to develop and operate the property. The Company is also registered in Manitoba. The authorized capitalization is 3,000,000 shares of $1.00 par value. Gilbert LaBine was appointed president of the Company, with James Houston as mine manager. Following completion of a diamond-drilling programme, planned in 1933, it was decided to install a mine plant capable of carrying development to a depth of 1,000 feet. A transmission line, 5 miles in length, was built to the Great Falls-Central Manitoba line of the Manitoba Power Company, Limited.

Jan 1, 1939

By K. D. Genn, A. Mucha

This paper deals with Hilton Mines' approach to the maintenance of wear items such as truck boxes, shovel buckets, tractor pads, crawler sprocket idlers and the drop-ball. Each will be given a brief. description as to application, design, kind of materials involved and type of wear. The maintenance procedure is then outlined in terms of materials used, preliminary preparation, and welding and machining practices. The service history of new and re-paired items and the relative economics of repair vs replacement will then be presented.

Jan 1, 1969

By C. A. Pickles

Nickeliferous limonitic laterite ores contain considerable free moisture. In this research, the application of microwave radiation for the drying of this ore was investigated. The effects of sample mass, initial moisture content and porosity on the microwave drying rate were studied and the results were compared to those obtained with conventional drying. Microwave drying rates of two to three times the conventional values were achieved. Further enhancement of the microwave drying rate was realized by increasing the flow rate of air over the sample or by operating at reduced pressure. The high microwave drying rates were attributed to the inverted temperature gradient which resulted in internal heating and boiling and this in turn promoted movement of the water, both as liquid and vapour, to the surface.

Jan 1, 2005

By J. Kouam

Al-Si-Cu and Al-Si-Mg alloys are widely used in several applications. Although they can be produced near-net-shapes, products made of these alloys very often require some machining. The purpose of this study is to evaluate the machinability of A319 and A356 under TO and T6 conditions. The machinability was assessed using during dry drilling machining process and the machinability indexes used are the chip form, the chip breakability and the cutting forces. It is found that 319 and 356 exhibit different machinability behaviors, especially in the T6-condition in terms of forces requirements, chip breakability and chip segmentation. It is also found that both the microstructure of the workpiece materials and the machining conditions significantly affect the chip formation mechanism, and therefore, the machining parameters could be selected to promote a chip form that is easily manageable in production.

Jan 1, 2011

By George Langford

Introduction The fiftieth anniversary is, for an individual or a society, an appropriate time for a review of the past so that events and experiences may be viewed m perspective, and thereby serve as a useful guide to the future. In this review of mining geology it is proposed to set forth the situation as it was when the Institute was founded, and then trace the developments during three appropriate periods-the first from 1898 to 1918 the second from 1919 to 1939 and the third from 1939 to 1948. Mining activities were widespread in Canada in 1898 and some of the operations were considered large for their day. The total value of the metals produced in that year was $21,705,854, and in the case of five metals the output had a value in excess of one million dollars. In order of importance these were gold, silver, copper, nickel, and lead. The important producing areas were ova Scotia, Quebec, Ontario British Columbia, and Yukon. This diversification of the mining areas and the metals produced created an interest in mining throughout Canada, and was an important factor in making Canadians conscious of their mining industry. In the year 1898 geology was a recognized science. The principles of physical geology were well known, but the same cannot be said of economic geology and structural geology. Ore deposits and their occurrence had been studied chiefly in Europe. A great many important observations had been made but the theories linking these facts together were still m a formative stage. The same condition was true of structural geology. These two branches of geological science which are so important in what is now called 'mining geology', had not progressed far enough to be of practical assistance mining operations. For this reason, geologists were regarded as dreamers in ivory towers-a concept chat still lingers in the minds of those who have not kept abreast of the growth of the science.

Jan 1, 1948

By Frank Martonhegyi

"The objective of this paper is to review the coal basins in the Canadian part of the Western Cordillera to aid their understanding, and to aid in finding and proving places of economic coal mining potential. Coal occurs in eugeosynclinal basins in the Western Cordillera which evolved through three stages: -from systems of volcanic arcs in the Late Jurassic to mid-Cretaceous; -through an intermediate stage with deposition in increasingly restricted successor basins in Jurassic to Early Tertiary; -to a continental stage by the Eocene. Minor coal seams occur usually in late volcanic arc stage sediments bur they can be locally thick as they are on Queen Charlotte Islands. Successor basins usually show a marine-paralic-limnic evolurion. Signijicanr coal deposits occur in the tarter two sequences in the Whirehorse (Tantalus) and Bowser (SkeenaSusrur) basins. Currenr activities are intensive in the more accessible Bowser Basin, for example at Telkwa, Susrut River and on the Groundhog coal field. On Vancouver Island major coal seams occur in cyclic sediments, but the more accessible deposits are mined our. Exploration renewed recently in the less accessible northern part of the Island, for example Quinsam, for surface mineable coal. The Western Cordillera is a mosaic of allochtonous tectonic blocks. They originated from the south and were displaced northward by several hundred kilometres. Many Tertiary coal basins are related to strikeslip transcurrent faults along which the later part of displacement took place, for example the Dawson coal area in the Tintina Trench. Tensional and dipslip normal faulting also created or enhanced sites for thick peat accumulation. For example at Hat Creek 280 m of coal occur in a 550 m section. Secondary structures are often better exploration targets than the main fault zones. Pluvial and alluvial fan environments away from the main drainage are usually the favourable sites for thicker and cleaner coal deposition."

Jan 1, 1985

By A. Alfantazi, M. Mahon

The current efficiency in zinc electrowinning is a key indicator of the performance in a cell house. This is typically measured by comparing the weight of the cathode to the electric current applied over the deposition period. This calculation can be cumbersome because the deposition history of each pulled set of cathodes will be unique. It will depend on the applied current and electrolyte conditions from onset of deposition until the cathode is removed and stripped. Not accounting for these can introduce errors to the calculated current efficiency. To track this history and reconcile the current efficiency, a time based computer process simulation was made of an industrial cell house. Two months of hourly recorded measurements from the cell house were input to the simulation, including current to the cell houses, concentrations, flow rate, and temperature of the purified leach solution. The simulation’s predictions of the concentration of zinc in the circulated, spent, and returned electrolyte all showed good agreement with the industrial data over the two months giving a validated zinc balance. The simulation was then tuned to predict the instantaneous current efficiency for all times, as well as the expected masses for the deposits given their deposition history.

Jan 1, 2014

By Chris M. Healey

"The Jasper Gold mine in northern Saskatchewan produced a total mill feed of 140 127 tonnes at an average grade of 19.0 g/t Au. Both diamond drilling and chip samples from underground workings returned extremely high values, up to 12851 g/t (375 oz/T) Au over 0.10 meter from a chip sample. In the presence of such extremely high grades, the accurate estimation of reserves is a major problem.In the first part of this study, production data from the mine were used to evaluate the results of a variety of reserve estimation techniques in this environment. In two out of three cases studied, indicator kriging with assays cut to 342.9 g/t (10 oz/T) gave extremely good results. In the third case, however, indicator kriging gave unacceptable results. Instead, lognormal kriging of uncut data gave the best results.Secondly, from the same database, a number of drill-hole spacings were simulated, and reserves estimated from the simulations. As may be expected, the results of this analysis show increasingly better results with tighter drill-hole spacing. However, even with a 5 m by 5 m spacing the variation from actual grade was quite large. This is not a systematic under- or over-estimation of grade, rather a random scatter of results.The results of this study show very clearly the problems of deriving good estimates of reserves when extremely high-grade samples are encountered. There is a high degree of randomness to this data base, so reserve estimation in this situation will remain a high-risk operation."

Jan 1, 1993

By David G. Baskin

"THIS DEPARTMENT is unique in that it operates in the production stream and also provides an essential service. Its operating function consists of scheduling an ore train to haul 10,000 tons per day over 17.1 miles of track and switching all incoming and outgoing rail equipment on 2.2 miles of track at the minesite and 6.2 miles of track at the metallurgical site. The service it provides is traffic control of all incoming commodities and all outgoing concentrates, metals and acid by rail and truck, even extending to port and ship control for overseas shipments (Fig. 46). Although they cover many miles, the railroad and traffic department employees operate very efficiently, as indicated by the following organizational chart:Railroad and Traffic Superintendent ................ 1Railroad Supervisor .............................................. 1Assistant Railroad Supervisor ........................ 1Track Foreman ...................................................... 1Trainmen ............................................................... ... 4Switchmen ............................................................... 4Trackmen ................................................................ 10Traffic Supervisor ................................................ 1Clerk Steno ............................................................ 1Clerks ...................................................................... 3"

Jan 1, 1974

By Denis Yaychuk, Gary Billingsley

The economic eva luation of a mineral property or mining venture should include the quantification of ri k as part of the analy is. The re ults of such an analysis provide the decision-makers not only with the most likely financial outcome and the probability of achieving that or any other outcome. but al o with a ranki ng of the relative impact of all the ri sk factors. These type of resu lts offer more complete information for investment and technical deci ions than the traditional cash flow/ ensitivity analysis. In addi tion. by attempting to quantify ri sk. the personnel providing the va ri able input are forced to take a much clo e r look at the data involved, and are fo rced to work together. the reby increa ing substantially the awa reness of the impact their work and others· work has on th e outcome of the analysis.

Jan 1, 1986

By F. P. Hassani, Jacque Ouellet, M. Hossein

A laboratory investigation was undertaken to evaluate the effectiveness of different binding agents in a paste backfilling operation suitable to be used in a sulphide-rich environment. Different combinations of Portland cement and fly ash type C as well as ferrous slag were used as the binding agents. The unconfined compressive strength of the samples was measured for extended curing periods. The results indicate that the addition of 3% slag in the binding agent mix could produce strengths up to 0.5 MPa in the samples under investigation. For higher binding contents, the addition of Portland cement will lead to higher availability of calcium hydroxide and calcium aluminate, which are susceptible to deterioration from the phenomenon known as sulphate attack. Using slag, on the other hand, will reduce the permeability, availability of calcium hydroxide, and dilute the calcium aluminate ions reducing the susceptibility of the samples to sulphate attack. However, gypsum will form which could have the same detrimental effect on the strength of the treated matrix. Therefore, special attention must be given to the content and properties of agents used to activate the pozzolanic properties of the slag.

Jan 1, 2001

By P. M. Pearson

This paper describes the principles ()f systems engineering and their application to the various transport problems confronting the mining industry. The organization of mining operations into sub-system design problems is explained.

Jan 1, 1970