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By T. Motegi

Semisolid casting provides grain refinement of the cast structure and prevents macro-segregation. The conventional semisolid slurry is obtained by electromagnetic or mechanical stirring. In our process, the magnesium alloy (AZ31) slurry is made using an inclined cooling plate instead of the conventional methods. The slurry obtained is cast into a twin-roll caster and makes a continuous sheet of 2 or 3 mm thick. The most important factors that influence the sheet casting are the casting temperature and twin-roll speed.

Jan 1, 2007

En quoi consistent les études de suivi des effets sur l?environnement (ESEE)? Les ESEE constituent une méthode de suivi scientifique que l?on peut employer pour déterminer la santé des écosystèmes aquatiques (qui peuvent être touchés par l?activité humaine) et l?efficacité des mesures de protection de l?environnement. Les ESEE sont des évaluations scientifiques itératives du poisson, de l?habitat du poisson et des ressources halieutiques. Le programme comporte des phases séquentielles de deux à six ans de suivi, d?interprétation et de compte rendu au cours desquelles la fréquence et le type de suivi dépendent des résultats des études précédentes. Le programme des ESEE pour les mines de métaux est fondé sur un accord conclu à l?unanimité entre les intervenants. Les exigences du programme et les guides techniques connexes ont été élaborés à la suite d?une consultation multilatérale à laquelle ont participé les représentants du secteur privé, du gouvernement et des collectivités. Toutes les mines assujetties au Règlement sur les effluents des mines de métaux (REMM), aux termes de la Loi sur les pê ches, doivent procéder à une ESEE dans le cadre de l?autorisation qu?ils ont reç ue de rejeter des effluents. Le REMM a été enregistré le 6 juin 2002 et publié dans la Partie II de la Gazette du Canada le 19 juin 2002 (SOR/DORS/2002-222).

Nov 1, 2002

By J. W. Gregg, P. M. Dranchuk, D. L. Flock

"From preliminary investigations it has been observed that although evaporation losses may be estimated by comparing single values of certain physical properties of crude oils and their evaporation residues, such techniques possess little accuracy unless both the evaporation process and the variation of the property as a function of the process are completely known. The accuracy of estimation may be increased somewhat through the comparison of property mid-per-cent curves. Further increases in accuracy are possible if bottoms yield •curves rather than mid-percent curves are used. The use of both the mid-percent and bottoms yield curves however involves a prohibitive amount of effort in most cases. Examinations of distillation bottoms from Hempel type distillations carried to end points just short of the cracking point have indicated that these bottoms are not appreciably affected by the evaporation process. It was further observed that bottoms of identical API gravity, obtained from a crude oil and its evaporation residues behave as if they were pure components which were unaffected by evaporation. Based on these observations Hempel distillation bottoms of equal API gravity were obtained for a crude oil and its various evaporation residues from API gravity bottoms yield curves. The volume percent of these bottoms in the crude oil and its residues were used to calculate the evaporation losses suffered by the crude in order to yield the various residues. The results indicate that, although further refinements in technique are required, it is possible to calculate evaporation losses with an accept-able degree of accuracy through the use of this method."

Jan 1, 1960

By Glen A. White

The level of impact and mitigating measures that are forecast in an environmental assessment (EA) for a new, or significantly modified, metallurgical processing facility or mine are taking on increasing importance during the subsequent life of the facility. The basic premise is that one is authorized to operate within the envelope defined by the approved EA. Operations inevitably change as they develop and mature, and at some point, one is faced with the prospect of re-doing the original EA work. This can lead to significant development delays. Cameco Corporation (Cameco) has played a major role in developing the northern Saskatchewan uranium mining industry over the past decade. Through the EA process, the company has developed ideas on what works well in generating approvals that give the operator some future flexibility. Early introduction of concepts for potentially different mining and processing methods, as well as contingency plans if things do not work out exactly as predicted in the original EA, can make subsequent regulatory approval for change a more efficient process. One must also preserve the principles of open consultation upon which the EA process was originally based. As such, involvement and support from local communities and other stakeholders is required to ensure the long-term success of the EA process.

May 1, 2004

By W. M. Armstrong

This paper compares research on development efforts in various countries, consideration being given to gross expenditures, manpower involved, source of funds, sector of performance and type of activity. The Canadian R & D activity is then reviewed, particularly as applied to the industrial sector, the problems of applied research in Canada are discussed and some remedies are suggested.

Jan 1, 1968

By J. W. Matousek

The heat content of the waste slag from a typical smelting operation methods for estimating the thermodynamic properties of smelting slags, to include: -- heats of formation -- heat capacities (specific heats) -- heat contents -- melting temperatures -- heats of fusion The techniques are illustrated with the analyses of a nickel reverberatory furnace slag from Copper Cliff, an iron-making blast furnace slag, and a "lateritic" slag from a ferronickel operation in Colombia.

Jan 1, 2007

By J. Dong

"A “green” collector project has been initiated at Vale Base Metals Technology Development to replace xanthate. Bench and miniplant testwork showed comparable metallurgical results between xanthate and DTC (sodium dibutyl dithiocarbamate), a “greener” collector. During the first DTC plant trial, a strong interaction between the process water and DTC negatively impacted the metallurgy. The subsequent investigation showed that the quality of process water including suspended solids and dissolved metal ions had a significant impact on the performance with DTC, while less so with PAX. This paper explains these differences using UV spectrophotometry and batch flotation tests. INTRODUCTIONVale Base Metals is dedicated to sustainable mining and mineral processing. One of the key activities is to find a “greener” collector to replace xanthate (PAX: potassium amyl xanthate), which decomposes during storage and flotation causing CS2 emissions in the work place. As the most promising candidate, DTC (sodium dibutyl dithiocarbamate) was evaluated in the lab and miniplant (Dong & Xu, 2011). Consequently, a plant trial was conducted in the winter of 2010. However, the results were not as good as expected. The subsequent investigation showed that the quality of process water played a significant role in the metallurgical performance with DTC but less so with xanthate.From test work in 1996 and 1997, a series of batch tests were performed at Clarabelle Mill to investigate the winter/summer metallurgical shift with xanthate. As shown in Figure 1, the winter metallurgy was considerably worse than the summer metallurgy (Xu & Wilson, 2000). At 80% pentlandite recovery, the concentrate (Cu+Ni) grade was 21% in the winter and 26% in the summer. At 23% (Cu+Ni) concentrate grade, pentlandite recovery was 85% in the summer and 70% in the winter. In the summer, the process water is much cleaner, with very low concentrations of dissolved metals ions and suspended solids; while in the winter, the water is yellow and cloudy, with much higher suspended solids. Based on these results, it was concluded that the process water in winter has a detrimental impact on metallurgy."

Jan 1, 2012

By Juan Asalgado

The JORC and NI43-101 codes impose that mineralized material has a reasonable prospect of economical extraction to be classified as Mineral Resource. For deposits close to surface and amenable to open pit mining, it is easy to show reasonable prospect of economic extraction running a Lerch-Grossman optimization. The Lerch-Grossman pit provides a transparent and repeatable way of separating the Mineral Resource (within the pit) from the remainder of the mineral inventory (outside the pit). Deposits amenable to underground mining are more challenging because of the variety of the underground methods. AMEC developed a stand-alone software package that outlines the material which has reasonable prospect of economic extraction for open stoping, block caving, sublevel caving and room and pillar. The software takes a block model file in ASCII and exports a 3D surface outlining the part of the mineralization that has a reasonable prospect of economic extraction, and which the Qualified Person can smooth out manually if required.

Oct 1, 2009

By R. H. Watson

A paper read by J. A. H. Church before the Northern Alberta Branch last February described a method of working thick inclined coal-seams from the dip upwards, with the view to preventing fire risk by using water for the stowage of waste workings, and extinguishing a conflagration should such break out, was favorably received; but there was some doubt as to the cost of such a method, as it involves a retreating system, which might prove too expensive for practical adoption. Let us consider a typical leasehold such as we are familiar with in the Rocky Mountains. The leasehold is crossed at one end by a mountain river, which is cut by the outcrop of a seam of coal, 30 feet in thickness, pitching as shown on the drawing herewith, which also shows the general line of the outcrop in elevation through the leasehold, which is two and a half miles long and contains 1,500 acres. The average lift is about 600 feet above river level and drilling has proved that the coalseam can be tapped at a depth of 1,500 feet, 2,000 feet down the pitch from the outcrop in the river, all as shown in the illustration, which is typical enough of our mountain conditions to serve the purposes of comparison of methods. We take up the leasehold and invest $30,000 to pay for drilling and prospecting; $30,000 more for the price of the lease to locator or holder, and say $100,000 to pay for a railway spur (it might cost twice this sum, but we are only comparing two methods in the same location) and "now we are ready to consider equipment and the cost of development.

Jan 1, 1924

By Muhammad Zaka Emad

Cemented rockfill (CRF) is a mixture of rock aggregate and binder slurry. It is a stiff backfill, it is fast curing, its operation is simple, placement rate is reasonably high and no drainage is required. The main demerit of CRF is failure of exposed faces causing ore dilution, which can be associated with the fill placement method. This paper discusses the effects of two placement methods being practiced by mines and numerical modelling is used as a tool to evaluate stability of the backfill column. In the first method, practiced in longitudinal retreat mining of a narrow vein deposit, the rockfill is hauled and dumped into the stope with a LHD scooptram. Once dumped, cement slurry is sprayed into the stope. In the second method, a raise situated centrally above the mined stope is used to convey already mixed CRF into the stope. Stopes are mined out transversely in primary and secondary blocks in a sublevel stoping system. Problems of poor mixing in combination with both placement methods are discussed. The two backfill placement methods are analyzed for blast induced vibration damage using the dynamic Flac3D modelling technique accounting for rock mass and fill damping characteristics, and a pressure wave is used to simulate the blast vibrations. Fill heterogeneity has also been considered for the two cases and results are compared.

Jun 1, 2012

By Peter M. Power

A microscopic study was made of a series of simultaneous slag and metal samples taken from a low carbon basic open hearth heat. An attempt was made to identify the various micro-constituents found. As the various impurities in the bath are oxidized, the metal structure changes from that of high-phosphorus white cast iron to that of low.-carbon steel. A detailed study of phosphorus distribution is included. The acid run-off slag has an .acicular orthosilicate structure which changes on 'shape-up' to a very basic tri-calcium silicate and calciuim ferrite structure. Many unidentified minor constituents are present in the slags. Though metallography will never replace chemic.al analysis of the bath, the microsopic study of polished slags has some promise of being useful in slag control work.

Jan 1, 1956

By M. Romana

"RMR geomechanics classification is being used all over the World as a useful tool for tunnel predesign and construction. Bieniawski (1989) provided guidelines for tunnel excavation and support, according RMR numerical values; guidelines which are now included in almost all tunnelling books, regulations, and Internet portals. But in the last 25 years tunnelling techniques have changed and some of the guidelines have become obsolete.. The conditions of tunnels for the 1989 guidelines application were: horseshoe shape; 10 m width; vertical stress < 25MPa; construction by drilling and blasting. Actually a substantial number of tunnels are mechanically excavated. The tunnel themselves are now bigger: a span of 14 m. is very common for transportation tunnels. The guidelines included the following concepts: excavation method, rock bolts (20 mm diameter, fully grouted), shotcrete, steel sets. There is an increasing gap between the 1989 guidelines and the practice: in many tunnels different to-the-case excavation and support requirements are established. Bieniawski himself has published a paper (Lowson & Bieniawski, 2013) with different guidelines based in Lowson’s practice, with no explanations and/or justification.In this paper a new set of RMR tunnelling guidelines is proposed taking account of the actual industry conditions, and increased safety regulations. The 5 classes’ limit RMR:values (80,60,40,20) are no more useful actually: Values of RMR (70, 50, 30) are used in practice to define quite different tunnelling techniques. Consequently a 10 subclasses system is proposed. Each subclass covers a span of 10 RMR points. As the number of mechanically excavated tunnels has increased a new correction factor is necessary, according the excavation method.The proposed 2014 RMR guidelines are for tunnels 10 to 14 meters wide, the world practice for new roads/railways tunnels. Many tunnels for water/ services are smaller with smaller support needs. Wider than 16 m caverns are out of the RMR system.It is not possible, nor desirable, to propose only a value for support in each subclass. The new guidelines propose an interval of values for certain types of support. More pessimistic values must be chosen for wider tunnels, tunnels with lower RMR values in each class and cases when a higher safety factor is asked for. More optimist ones are chosen for narrower tunnels, and higher RMR values. Some alternatives are almost complementary, others are contradictory. Sometimes several different techniques are proposed Guidelines are not automatic options. Good engineering judgment must be used when choosing between the different alternatives. Guidelines are not mandatory suggestions."

Jan 1, 2015

By T. H. Etsell, P. Kerr, Qi Liu

"The objective of this investigation was to study the reaction mechanisms during the reduction of iron oxides in the presence of calcium chloride and carbon black as a simplified iron segregation process. The gas phase was analyzed by mass spectroscopy and the solid reaction products were analyzed by scanning electron microscopy. Mass spectroscopy, combined with thermogravimetric analysis and differential scanning calorimetry, revealed the presence of several gases at elevated temperatures over time, and the scanning electron microscope in combination with energy dispersive X-ray analysis illustrated the growth of a metallic iron phase on or near the carbon substrate. The results correlated well with similar copper and nickel segregation processes, but also introduced new insights that challenge the simplicity of the current models. The formation and transport of gaseous iron species to the carbon substrate in the presence of steam and hydrogen were evident during the reduction process that was studied; however, there is more happening at a mineralogical level, based on evidence of a liquid phase resulting in substantial growth due to an apparent fluxing effect created by the calcium chloride.These results help to better explain the chemical reactions and, in turn, the thermodynamics and kinetics of iron segregation processes related to the beneficiation of low grade complex iron ores. The results are also applicable to the production of metallic iron and concentrated titanium dioxide from ilmenite ores. The benefit of this process is that it allows ores in which the iron minerals are intimately associated with gangue minerals to be processed in circumstances where conventional mineral processing techniques are unsuitable or incapable of upgrading the material."

Jan 1, 2016

By Q. Han

A modified cast-on method has been developed to reinforce aluminum castings with steel insert. Defect-free bond between the steel insert and the aluminum casting has been consistently obtained. Data obtained from a push-out experiment indicated that the bond strength was much higher than that obtained using the Al-Fin approach. This paper introduces this modified method in four sections: the coating of the steel pins, the cast-in method, microstructure characterization, and the bond strength. The section on the coating of the steel pins contains coating material selection, electro-plating technique for plating Cu and Ni on steel, and diffusion bonding of the coatings to the steel. The section on cast-in method deals with factors that affecting the quality of the metallurgical bond between the coated steel and the aluminum castings. The results of microstructure characteristics of the bonding are presented in the microstructure characterization section. A push-out experiment and the results obtained using this method is described in the section of bond strength/mechanical property.

Jan 1, 2015

By R. S. Fitzpatrick, P. Hegarty

"Gravity separation is a key technology in the recovery of a range of mineral ores including coal, tin, tungsten and tantalum. One of the problems associated with gravity concentration is that recovery is traditionally lower than for other separation techniques such as the flotation of base metals. Any improvements in recovery will, therefore, have a significant effect on the economics of operations of this type. More accurate, robust modelling of gravity separators is one means of achieving greater recoveries. Furthermore, better modelling can lead to more informed equipment selection and process design for potential economic deposits.Previous models for gravity separation equipment have typically relied on simple metal mass balances from samples of the separated products. However, with advances in technology there is a ready availability of analytical instruments for the automated quantitative determination of mineralogy. Instruments such as the Mineral Liberation Analyser and QEMSCAN make it possible to estimate particle size and density (related to mineral liberation and association) which are the primary factors in gravity separation. Models produced using quantitative mineralogy of feed streams will be potentially superior to those produced historically.This paper describes test work undertaken on a wet shaking table using a synthetic ore. The objective of this test work was to develop a model to predict the effect of changes in feed ore characteristics on shaking table performance by measuring quantitatively the mineralogy of the feed material. Particles were divided into size/density classes based on the results of QEMSCAN analyses.It was found that it was possible to use data from QEMSCAN to predict the recovery of size/density classes and to predict the effect of changes in the relative abundances of these classes on the separation. This model can potentially be used to adjust operating variables to maximise grade and recovery by monitoring the input feed. Care was needed when utilising QEMSCAN data to ensure representivity."

Jan 1, 2016

By Jennifer Abols

In July of 2013, Lundin Mining acquired the 2,000 tpd Eagle nickel and copper project from Rio Tinto. The project had been put on hold earlier in the year and construction was approximately 50% complete. Lundin immediately accelerated project activities and by September of 2014 the project was constructed, commissioned and ramping up. The newly commissioned facilities went on to reach design throughput, recovery and product quality targets by the end of the year. This was accomplished ahead of schedule and below budget despite numerous obstacles including the worst winter on record in the past 50 years for the area. What led to the success of the project, and in particular the commissioning phase of the project? This paper takes a high level look back and provides an overview of the methodology used, key issues encountered and lessons learned to answer this question.

Jan 1, 2015

By Zara Hosseini

?Microseismicity ?Seismic Systems ?Intrinsically Safe and Explosion Proof Seismic System ?Case studies: ?Gas Drainage Optimization ?Fault Identification ?Conclusion Seismic Event ?Occurrences in which energy is released in the rockmass creating a series of seismic waves propagating throughout the rockmass ?Can cause a Fall of Ground or CoalBurst Factors creating Seismicity: ?Mining at Depth ?High stress zones ?Major geological structures ?Mining practices and strategies ?Mining activities i.e. drilling and blasting

Aug 1, 2013

While this paper is directed towards the ?Bellambie? type of rope attachment, the principles can be applied to any brand of rope fitting however, it is a only a broad outline and the specific installation and maintenance procedures can be obtained from the attachment supplier. The types of attachment to be discussed are:- ?Thimble Type rope cappel ?Wedge Type cappel ?WRC Rope Clamp ? (Rope Glands) ??Hoist and Balance Rope Sockets In each case, the assembly and stripping (disassembly) plus the basic maintenance procedures is briefly described. A guide for Risk Assessment is also included but because of his familiarity with the installation, the end-user is in the best position to draft the final version.

May 1, 2003

By Ryan L. Veenstra

This paper presents a modelling study of a cemented paste backfill in an underground stope. The model was developed to help provide a better understanding of what is happening in the stope during the filling stage of the stope. In order to do this, the model incorporates the paste rise rate, stope geometry, and time-dependent input parameters. This paper looks at the effect of geometry in two parts. The first part compares a series of simple rectangular stope models. These models differ in size both in two and three dimensions. The second part compares the results of four 2D models together and then to the field instrumentation data. Part of this section introduces the geometry and instrumentation within the test stope.

Jun 1, 2012

By Real Daigneault, François Robert, J. Paul Golightly, Jean-Yves Cloutier, Jayanta Guha, Pierre Pilote

"The Casa-Berardi East, Center and West deposits, located in the Archean Abitibi, Sub province, are hosted by volcanic and sedimentary units of varying compositions, less than300 m from the Casa-Berardi fault (CBF). The CBF, a brittle structure, represents an increment in the structural evolution of a regional-scale deformation zone showing ductile-brittle behavior known as the Casa-Berardi deformation zone (CBDZ). The CBDZ is characterized by a mylonitic Sc1 foliation which is folded a.n4 deformed by a later sczfoliation in high strain zones.Four generations of quartz vein and fracture systems have been recognized within the Casa-Berardi deposits. Most economic gold mineralization, occurring in the second generation system, is found within high strain zones. This system hosts three types of mineralized structures: (1) banded quartz veins; (2) swarms of veins and mineralized host rocks; and (3) disseminated sulphides along fractures. An early carbonate hydrothermal alteration zone (pre- to syntectonic) surrounds the deposits. Alteration associated with gold mineralization is contemporaneous to late ( syn- to post-tectonic) relative to the development of progressive deformation in the CBDZ. The geological characteristics and paragenesis of the four quartz vein and fracture systems developed as an integral part of the geodynamic evolution of the Casa-Berardi deformation zone."

Jan 1, 1990