Search Documents

By A. Zarei-Hanzaki, O. Golmahalleh, S. M. H. Hosseini, H. Azizi-Alizamini

The main importance of acicular ferrite microstructures arises from their desired combination of mechanical properties in comparison with the bainite and ferrite-pearlite microstructures. Several factors affect the microstructural transition from bainite microstructure into the acicular ferrite one. As is well established any factor corrupting the prior austenitc grain boundaries nucleation potential, such as the thin layer of allotriomorph ferrite and the austenitc deformation inhomogenities may promote the acicular ferrite formation instead of bainite. Accordingly, this study deals with the effects of the aforementioned features on the acicular ferrite formation in low carbon microalloyed steel. The results indicate that the formation of strain-induced ferrite at the prior austenite grain boundaries accompanied by deformation inhomogenities in the austenite grains change the effectiveness of allotriomorph ferrite on acicular ferrite formation from active to inert one.

Jan 1, 2004

By Z. Y. Ma, H. Y. Yang

The process of microwave-ultrasound assisted leaching of valuable metals from copper anode slime was proposed in this paper. Design of experiments has been used to study the effect of the main leaching parameters, such as microwave power, ultrasound power and reaction time. The central composite design (CCD) was used to predict the maximum leaching efficiency of copper, tellurium and selenium. The experimental data obtained were fitted to a second-order polynomial equation, and they also were analyzed by analysis of variance (ANOVA). The 3-D response surface plots and the contour plots were applied to determine the optimal conditions. The optimum conditions of microwave-ultrasound assisted leaching process were: microwave power 834W, ultrasonic power 638W and reaction time 403s. Under these conditions, the experimental leaching efficiency of copper, tellurium and selenium were 98.88±0.56% 98.96±0.78% and 98.57±0.67%, respectively, which agreed well with the predicted values.

Jan 1, 2014

By L Munholand, G. Soucy, P. Quintal

This work presents early results from the first study to optimize the hydrodynamics of a Plasma Lift Reactor (PLR). The PLR is designed to break down organic contaminants in aqueous solutions. New experimental results are presented for air/water tests and for plasma degradation of organic contaminants in Bayer liquor. In addition, a multiphase Computational Fluid Dynamics (CFD) model has been developed which predicts the hydrodynamic behavior in the PLR. These results of this work suggest the PLR is effective at reducing contaminants in the Bayer liquor and that the CFD model adequately describes the hydrodynamic flow.

Jan 1, 2005

By V. G. Papangelakis, J. E. Dutrizac, G. Azimi

A new model capable of predicting the solubility of calcium sulphate solid phases in zinc sulphate processing solutions from 25 to 95°C was developed. The model uses the Mixed Solvent Electrolyte (MSE) model of the OLI systems software to calculate the mean activity coefficients of the electrolyte species. The model was tested using recently developed experimental measurements. It was shown to predict accurately the solubility behaviour of calcium sulphate in multi-component zinc processing solutions containing ZnSO4, H2SO4, MgSO4, MnSO4, Fe2(SO4)3, Na2SO4 and (NH4)2SO4. The model can also explain the complex effect of coexisting metal sulphates on the solubility of the CaSO4 phases. The model is a practical tool for assessing the process chemistry of a wide variety of complex aqueous processing streams.

Jan 1, 2008

By A. M. Bell

"Hallnor mine is in the township of Whitney, Porcupine district. To date, its production of gold has been second largest in the east Porcupine field. Ore was discovered in the property in 1936 by diamond drilling in overburdened country. This drilling was undertaken by Noranda Mines following the discovery of ore in conglomerate at Pamour 1 mile to the east.Milling commenced at the Hallnor in June 1938, and to the end of 1945 432,000 oz. gold had been produced from 889,000 tons of ore, giving an average recovery of 0.49 oz. a ton.The West mine of Pamour, the Broulan orebody, and the veins on the Hallnor and Bonetal are all parts of a mile long vein system that has been separated into three sections by cross faulting. In consequence, they could well have been described in one paper. In treating them individually the viewpoint obtained from each may lead to conflicting opinions, and any conclusions advanced in this paper on the general structure should be modified by the conclusions advanced in papers on the neighbouring properties.GENERAL GEOLOGYRock FormationsThe Hallnor orebodies occur within 400 feet of the contact between lavas and sediments, and may lie in either lavas or sediments. The lavas near the ore consist of flows of pillowed andesite and one flow of more acid and less sheared and chloritized lava locally named trachyte. These flows strike east-west and dip steeply. At the surface on the east side of the property the volcanics have been intensely altered to a massive carbonate rock having a north-south thickness in excess of 1,000 feet . This carbonate body extends west across the property with a plunge of 45° (Fig. 1)."

Jan 1, 1954

By Robert B. Parsons

"This article is based on a paper presented by Jim Scott at the 1988 annual convention of the Prospectors and Developers Association of Canada. The paper suggests a number of factors that might be taken into account in negotiating royalty terms.IntroductionRoyal ties are a part of mining life in Canada. They are used by many kinds of individuals in many kind s of situations. Prospectors commonly take royalty interests back when they transfer claims to development companies. Mining companies disposing of undeveloped (or sometimes even developed) properties are often paid at least in part by royalties. Royalties are even used by institutional investors with no other connection with the resource industry.Such different royalty holders have different investment goals, different cash flow requirements, and different risk / return preferences. These differences have given rise to a number of different royalty type s. These types range from the simplest cents-per-ton royalty (where the operator pays a royalty at a fixed rate per ton milled) to net smelter return or ""NSR"" royalties (where the royalty is based on a percentage of the operator's NSR) all the way to net profit interest or ""NPI"" royalties (where the royalty is based on the operator's bottom-line net profit),The fundamental difference between the many royalty types is in the risk/ return relationship. The cents-per-ton royalty, for example, is relatively risk-free. Of the many economic factors which affect a mine, the only one which will affect the royalty holder is the amount of ore physically milled. On the other hand, the potential for significant gains under a cents-per-ton royalty is also very limited. The royalty holder will not share in any increases in the market price of the end product or any cost reductions achieved by the producer."

Jan 1, 1988

By Robert B. Parsons

"This article is based on a paper presented by Jim Scott at the 1988 annual convention of the Prospectors and Developers Association of Canada. The paper suggests a number of factors that might be taken into account in negotiating royalty terms.IntroductionRoyal ties are a part of mining life in Canada. They are used by many kinds of individuals in many kind s of situations. Prospectors commonly take royalty interests back when they transfer claims to development companies. Mining companies disposing of undeveloped (or sometimes even developed) properties are often paid at least in part by royalties. Royalties are even used by institutional investors with no other connection with the resource industry.Such different royalty holders have different investment goals, different cash flow requirements, and different risk / return preferences. These differences have given rise to a number of different royalty types. These types range from the simplest cents-per-ton royalty (where the operator pays a royalty at a fixed rate per ton milled) to net smelter return or ""NSR"" royalties (where the royalty is based on a percentage of the operator's NSR) all the way to net profit interest or ""NPI"" royalties (where the royalty is based on the operator's bottom-line net profit),The fundamental difference between the many royalty types is in the risk / return relationship. The cents-per-ton royalty, for example, is relatively risk-free. Of the many economic factors which affect a mine, the only one which will affect the royalty holder is the amount of ore physically milled. On the other hand, the potential for significant gains under a cents-per-ton royalty is also very limited. The royalty holder will not share in any increases in the market price of the end product or any cost reductions achieved by the producer."

Jan 1, 1989

By C. Caballero, M. Rosales, C. León, A. Valencia, R. Fuentes, A. Moyano

Slopping is the formation of waves in the converter due to the gas injection by tuyeres. Those waves produce a premature wearing of the refractory lining of the reactor due to its great amplitude. The affected zones are the tuyere line (outlet gas from tuyeres) and the front of this line. In the present work, a theoretical and experimental study is made to develop a theory that determines the variables involved in slopping, characterizing the more important parameters of operation in the phenomenon of slopping. In addition, this theory will allow for determination of new technological alternatives of the blast injection permitting to depress the slopping phenomenon.

Jan 1, 2007

By M. R. Henzinger, W. Schubert

"The quality of the backfill applied at a shield driven tunnel is of significant importance failure of the lining. The used material also affects the interplay between support and excavation behaviour.In this research the state of the actual bedding situation is investigated by an analytical approach, laboratory tests and numerical simulations. The numerical simulation using continuum methods have shown shortcomings. These shortcomings regarding the instability of large strain simulations restrict the possibility to reproduce the relocation of the backfilling material. The performed scaled model tests have shown that the regripping process of a double shielded tunnel boring machine affects the soil failure within the gap. With the analytical results the influence of the wall friction can be predicted. Therefore the angle of the failure surface can be determined. The results have shown that the wall friction significantly increases the failure angle. INTRODUCTIONFor tunnel boring machines (TBM) with single (SM) or double (DSM) shield, precast liningsegments are used as rock support. These segmental linings are installed within the protection of the TBM shield. In order to reduce the friction while advancing, the shield diameter is smaller than the diameter of the cutter head and therefore also smaller than the excavation boundary. The difference depends on the expected radial convergences. Since the lining segments are mounted within the shield the steering gap between the shield and the excavation boundary increases and is hereinafter called annular gap.In the process of tunneling in hard rock, the annular gap is usually filled with fine grained and closely graded gravel, termed as pea gravel. The backfilling process starts as soon as possible after the shield tail passes the lining. Due to the operational procedure within the working area of a TBM, a fully backfilled annular gap might not be established after every ring closure. This leads to an unfavorable distribution of the pea gravel leaving the segmental lining partially without bedding. Segmental linings can develop sufficient resistance only when properly bedded."

Jan 1, 2015

By Robert B. Parsons

"In all likelihood, Canada's mining industry would be adversely affected by corporate tax reform proposals actively being considered by the Department of Finance in Ottawa. When the next set of proposals for lax reform is released later this year as promised by Finance, the mining industry had better be prepared 10 take a hard look.IntroductionTwo federal budgets ago, in May 1985, Finance Minister Wilson tabled budget papers that were more massive in terms of volume than most federal budgets. Buried in this mass of documentation is a discussion paper entitled ""The Corporate Income Tax System-A Direction For Change"". When the discussion paper was tabled over one year ago, reaction from the business sector was almost nonexistent. By and large, the paper was regarded as nothing more than one more federal publication of mild academic interest.But, recent events suggest that this discussion paper for corporate tax reform could be the cornerstone for a series of changes to the tax laws which would have more profound and widespread effects for all sectors of the economy than any reform since 1971 . No industry in Canada can afford to ignore the movement afoot in Ottawa for corporate tax reform."

Jan 1, 1986

This document presents estimates of future "total cash cost per ounce" and "minesite cost per tonne" that are not recognized measures under United States generally accepted accounting principles ("US GAAP"). This data may not be comparable to data presented by other gold producers. These future estimates are based upon the total cash costs per ounce and minesite costs per tonne that the Company expects to incur to mine gold at the applicable projects and do not include production costs attributableto accretion expense and other asset retirement costs, which will vary over time as each project is developed and mined. It is therefore not practicable to reconcile these forward-looking non-GAAP financial measures to the most comparable GAAP measure. A reconciliation of the Company's total cash cost per ounce and minesite cost per tonne to the most comparable financial measures calculated and presented in accordance with US GAAP for the Company's historical results of operations is set forth in the notesto the financial statements included in the Company's Annual Information Form and Annual Report on Form 20-F, for the year ended December 31, 2009, as well as the Company's other filings with the Canadian Securities Administrators and the SEC.

May 1, 2011

By I. Demers

The abandoned Manitou mine site covers an area of approximately 190 ha near Val d?Or, Quebec. This old site has been generating acid mine drainage for several decades. In 2006, a partnership was established between the Quebec Ministry of Ressources Naturelles (MRN) and Agnico-Eagle Mines to reclaim the Manitou site using tailings from the nearby Goldex mine. These neutral tailings were to be deposited on top of the Manitou site. An extensive study was performed to evaluate specific reclamation scenarios to control acid mine drainage using Goldex tailings as cover material. The article first describes the global approach used for this evaluation, which includes in-situ hydrogeological monitoring, tailings characterization, laboratory column tests, and numerical modelling. Of the thirteen column tests, three were conducted to evaluate the parameters affecting the performance of covers made of Goldex tailings placed over the spillage area of the Manitou site. Geochemical and hydrogeological parameters were assessed during the leaching column tests for almost two years. The tests aimed at evaluating the effect of water table level and monolayer cover thickness on the overall performance. The testing procedure involved monthly leaching and measurement of geochemical parameters. Results indicate that water table position is the most important factor affecting the monolayer cover performance to control AMD. Based on these results, it was established that the water table must be located near the interface between the Goldex and Manitou tailings to effectively reduce AMD generation. Cover thickness also has an impact on cover performance, which is however less significant than the water table position. The testing scenario with a water table located at the interface with a one-meter Goldex tailings cover showed progressive improvement in effluent quality.

Aug 1, 2013

By J. M. Belland

This paper deals with the geology of the Smallwood mine in relation to its influence on mining and milling operations. Structure within the orebody, and variations in ore grade and material types, will be described and associated with the various drilling, blasting and milling operations. The orientation of planes of weakness, either bedding or jointing planes, and contacts between extremes in material types influence the size of the broken material. Generally speaking, variations in grinding rates and recovery can be associated with stratigraphic sequence and metamorphism.

Jan 1, 1966

By H. Thalenhorst

For an advanced mineral exploration project that has a ?nugget? issue making the assessment of the deposit grade difficult, a bulk sampling program using a sample tower can provide information that is otherwise not obtainable prior to actual production. This information includes the verification of predicted resource grades for the bulk sample tonnage (and, indirectly, of the methods and parameters used for the grade estimate), confirmation of the physical and grade continuity of the mineralization, and geotechnical data for a future mining operation. The information gathered will improve the input of a feasibility study, particularly with respect to expected mining grades, which are the key economic parameter for most mining projects. The bulk sample rejects can be used for pilotscale metallurgical testwork. Bulk sampling is also useful in cases of potentially biased drill-hole assay results and in the reliable determination of ore grade before shipment of ore from production or development operations to an external beneficiation plant. This paper presents a practical bulk sampling and sample preparation protocol, lists design features for the sample tower, examines the sampling errors that will be encountered, provides information on quality control procedures, and looks at the costs and benefits of such a program, based on the experience of undertaking bulk sampling programs during the period of 1985 to 2008.

May 1, 2010

RÉSUMÉ L’estimation la plus précise possible des coûts de minage est d’extrême importance pour les études de préfaisabilité afin de diminuer les risques financiers des projets miniers. Les méthodologies existantes d’évaluation des coûts de minage ne permettent pas de les évaluer avec des marges d’erreur acceptables tout au long de l’évolution des projets miniers. Elles visent à évaluer les coûts unitaires de minage des études préliminaires de faisabilité, pour les principales méthodes d’exploitation, en prenant pour l’hypothèse que ces coûts dépendent principalement du taux d’extraction journalière. Si cette hypothèse peut être justifiée pour l’évaluation du coût d’opération, elle est fort discutable pour l’évaluation des coûts de minage. Pour démontrer que cette hypothèse est inadéquate nous avons analysé la méthode d’exploitation la plus populaire sur le continent nord-américain c’est à dire celle par chambres vides avec retrait horizontal (Hr – Horizontal retreat), ou « Longhole » et celle avec retrait vertical (VCr - Vertical Crater retreat). Il ressort de cette analyse que les coûts unitaires de minage dépendent principalement des conditions géotechniques du massif rocheux et de la largeur du gisement et non pas du taux d’extraction journalière du minerai.

Jan 1, 2010

By E. S. Moore

GOLD was discovered previous to the year 1900 on the east shore of Emerald lake, Afton township, Timagami Forest Reserve. It was found in a small cavern in banded iron formation, close to the water's edge. This occurrence of gold was mentioned in several reports that referred briefly to this area, and prospectors evinced considerable interest in the region. It was not, however, until the Golden Rose Mining Company, which was incorporated in 1909, started operations that much work was done on the property. In 1915-16, this Company, under the direction of E. J. Townsend, the President, did a considerable amount of work. A small mill was built and ore was extracted from pits, trenches, and a one~ hundred-foot shaft. In 1927, Afton Mines, Limited, was incorporated to take over the property, and about thirty men were employed for a time. During 1934, the New Golden Rose Mining Company was organized to handle the property, and the Consolidated Mining and Smelting Company of Canada, Limited, undertook to develop the mine. In March of the following year, this Company began deepening the shaft from 100 feet to 500 feet. A considerable amount of drilling had previously been done on the hill of iron formation in which the mine is located. Further drilling was done from the surface, and altogether about twelve holes have been put down to test the formations. Over 2,000 feet of drilling has also been done from the underground workings. The mine is now known officially as the New Golden Rose mine, although to many it is better known as the Afton. To reach the property during the summer months, there is a boat trip of about thirty miles from Timagami, a wagon-road portage of one mile to Obabika lake, a boat trip of ten miles on this lake, and finally a wagon-road portage of one and one-quarter miles to Emerald lake. The mine lies about three-quarters of a mile down the east shore of the lake. A 75 h.p. Diesel engine and compressor were taken in over this' route last summer, and it is evident that the transportation problem is quite a serious one. Airplanes have been much in use, and a winter road runs from the mine to Chudleigh, on the .Canadian National railway near Sudbury.

Jan 1, 1936

By D. Bai, F. Hamad, S. Abraham

For the integrity of welded structures such as pipelines, the toughness of the heat-affected zones (HAZ) is an important property. This property is often specified in terms of Charpy V-notch (CVN) impact toughness and determined by the standard test method. An experimental study has been conducted in an industrial laboratory to measure the impact toughness of the coarse grain heat-affected zones (CGHAZ) of an X80 line pipe material. The field girth welding conditions in terms of heat input were simulated, together with special edge preparation to improve the targeted testing of the CGHAZ. The effect of toughness of the neighboring regions, in particular the weld metal, on measured impact toughness of the CGHAZ was investigated. The fracture paths of the CVN tested samples were examined by both optical and scanning electron microscopy. The deviation of segments of the fracture path into the weld metal was found to have a significant effect on the measured impact toughness of the CGHAZ.

Jan 1, 2005

By L. M. Oshinowo

The incorporation of advanced analysis tools, such as CFD, into the process plant design process has become possible through advances in commercially available computational fluid dynamics software and faster computers. Multiphase modeling is now typically employed in the design phase of process plant design at Hatch. The multiphase models include Lagrange-Euler and Euler-Euler treatment of the multiple phases. Additionally, mixture models with interface-sharpening algorithms are applied to the prediction of free-surface flows in complex geometry. CFD is applied to applications where traditional design rules are not applicable. The additional rigor of CFD modeling in 2D and 3D allows process engineers to come closer to realizing true virtual plant design. The objective of this paper is to outline the benefits and pitfalls in the application of multiphase modeling for rigorous design. Several application examples in the hydrometallurgical field will be presented.

Jan 1, 2005

By S. Orangi

A representative sample of ramming paste from a peripheral seam in an aluminium electrolysis cell was taken in order to develop a process to fabricate ramming paste samples in the laboratory. To this end, paste material was compacted in multilayers in a mould designed to be representative of peripheral seams in Alcoa's smelters. The density distribution in the representative sample was measured ranging from 1.51-1.76 g/cm3. The density range obtained by the proposed methodology in laboratory is 1.47-1.77 g/cm3. The results demonstrate that the proposed fabrication method adequately duplicates paste density from the cell for both one and two layer compaction. Finally, preliminary results related to the compressive strength and Young's modulus of laboratory samples were obtained at various temperatures and are presented in this paper.

Jan 1, 2011

By Laxman M. Amaratunga

Laboratocy flarmnability tests were perfonned on dust samples from Fraser Mine in a 1.2 L Lindenburg horizontal tube furnace to detennine the percentage of sulphur oxidized during ignition. The explosion pot ential of sulphide dusts depends on their degree of spontaneous oxidat ion, which was measured by the quantitative analysis of so2 gas released during ignition. Test results indicated that dusts with low sulphur content could exhibit a higher degree of oxidation than a sample with high sulphur content. txlst characterisation using image analysis techniques suggests that the structure and the texture of dust are important factors influencing the explosibility of sulphide dust at ignition temperatures. Therefore for safe mine operations% sulphur content cannot be considered as a reliable single index that could be used to predict the potential of a sulphide dust explosion. Physical, chemical and mineralogical characterisation of dust plays an important role in the detennination of suitable indices for the prediction and prevention of sulphide ore dust explosions.

May 11, 1988