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By S. Amira

In the last two decades, many new creep-resistant magnesium alloys have been developed for high temperatures applications. Their mechanical performance and corrosion behaviour were reported for various experimental conditions. However, these conditions often led to uneven comparison basis. In the present study the microstructure, mechanical properties and corrosion performance of four of these newly developed creep-resistant magnesium alloys were systematically compared. Specimens were obtained from experimental box-like components that were die-cast and thixocast in comparable conditions. Their mechanical and corrosion properties were compared using similar testing conditions. Results show that the creep resistance, strength and impact resistance of specimens are comparable but systematically lower compared to specimens cast under optimized conditions. The reduced concentration of elements such as Al, Ca, Sr and Ce lead to a decrease of the corrosion resistance of the magnesium alloys in 3.5% NaCI solution.

Jan 1, 2007

By P. A. Christopher, R. H. Pinsent

"The Adanac molybdenum porphyry deposit near Atlin, in northwestern British Columbia, was discovered in 1905. It was explored extensively between 1967 and 1980.The deposit is within a complex, multi-phase, quartz monzonite stock that is a satellite of the post-accretionary, Surprise Lake Batholith. Biotite K-Ar dates range from 703 ± 2.4 Ma to 71.6 ± 2.1 Ma, indicating a Late Cretaceous age of emplacement.The deposit comprises an irregular-shaped ring or halo peripheral to a quartz monzonite porphyry dome, or ""cupola': The shape of the ring, and of a smal~ fine-grained quartz monzonite intrusion, and the presence of higher-grade mineralimtion on the eastern flank of the cupola, suggest partial control by a preminera/ structure. The deposit is truncated by a steep, northwesterly dipping, normal fault (Adera Fault) that down-dropped the northern half of the deposit by a minimum of 100 mThe deposit lacks strong zonal alteration but there are narrow envelopes of potassic alteration around some veins and local zones of intense wall-rock silicification. There is considerable retrograde alteration along postminera/ faults and fractures.Molybdenite occurs in veins and fractures, many of which are relatively flat-lying. They occur in all phases of quartz monzonite. Molybdenum is the only element of economic significance. There are vein and skarn occurrences with tungsten, tin, lead, zinc and precious metals peripheral to the deposit.In 1981, Placer Development Limited reported an ""undiluted mineable mineral reserve"" of 151 971 000 tonnes grading 0.063% Mo at a cutoff grade of 0.04% Mo and a strip ratio of 1.5:1."

Jan 1, 1995

By W. A. Jones

THE Ross mine, a subsidiary operation of Hollinger Consolidated Gold Mines, Limited, is situated near the north end of lot 1, concession 2, Hislop township, Ontario. The property comprises the north half of lot 1, concession 2, and the south one-third of lot 1, concession 3. It is readily reached by a good motor road from the village of Ramore, 7.5 miles to the southeast on the Temiskaming and Northern Ontario railway. The-mine has been developed to a depth of 900 feet and the current daily production rate is about 260 tons. From the inception of operations in March, 1935, until December 31st, 1942, 455,720 tons of ore with a total value of $4,169,-316 have been milled. The silver to gold ratio of 1.48 to 1 is unusually high for Ontario gold mines. The deposit is interesting because the relationship between hydrothermal metamorphism and three successive stages of fracturing and mineralization is marked with considerable clarity. During the past seven years, detailed geological maps of the mine have been kept up to date, many thousands of feet of diamond-drill core have been logged, and numerous thin and polished ore sections have been studied. The present paper describes the structure and mineralogy of the orebodies.

Jan 1, 1944

By Anton Sizo, Alexey Klyashtorin

The Gunnar uranium mine operated from 1953 to 1961 on the shore of Lake Athabasca, in 1964 the site was abandoned, and the mine pit flooded. In 1981, the pit was found to be stratified with a chemocline at ~70 m by a sharp change in conductivity and TDS. The uranium concentration was ~700 μg/l on the surface, 320 μg/l at 50 m, and 2,900 μg/l at 110 m. The Ra-226 concentrations were 0.1, 0.06, 0.12, and 0.4 Bq/l. By 2017, the chemocline was ~60 m deep. The highest uranium concentration was 1150 μg/l and the lowest concentration (220 μg/l) was attributed to the chemocline. In the deeper column, the uranium content varied around 750 μg/l. The uranium distribution down the pit profile was aligned with DO, ORP, and TDS. Ra-226 averaged to ~0.4 Bq/l, Ra-226 and uranium profiles were inversely related with the respective maximum and minimum attributed to the chemocline. The uranium and radium amount accumulated in the pit by 2017 was 3,420 kg and 2,163 GBq, respectively. The uranium and radium apparent accumulation trend estimates to 64 kg/y and 41 MBq/y, respectively. A stable chemocline and no concentration gradients in the other parts of the pit suggest that the contaminants are unlikely to inflow from the bottom opening or outside the pit, but rather are mobilized from the pit walls. The contaminants are not in a steady state, and concentrations of both uranium and radium are likely to increase slowly in the future if no remediation occurs.

Jan 1, 2020

By V. M. Robb, F. Walraven, L. J. Robb

"The old Albert Silver Mine is a polymetallic deposit comprising concentrations of CuPb- Zn-Ag-U-F within a set of sub-parallel quartz-hematite veins which occur within the fine-grained apical phase of the 2050 Ma old A-type Bushveld granites. Mineralization occurs as an early pyritechalcopyrite- arsenopyrite-galena-sphalerite-(argentiferous) tetrahedrite paragenesis followed by a later, more oxidized assemblage comprising chlorite-hematite-fluorite-pitchblende. Accumulation of metals appears to have taken place at the interface between a coarse-grained porphyritic granite and an overlying fine-grained phase: veins occur in the latter and represent leakage of magmatic fluids from the differentiated, water-saturated, subjacent granite.Mineralization processes in the Bushveld granites are believed to be related to long-lived circulation of dominantly magmatic fluids stimulated by the high heat productive capacity of the host rocks. Endo- and exogranitic tin-tungsten and base metal mineralization formed during an evolving hydrothermal system that lasted for several hundred million years, forming innumerable small- to mediumscale polymetallic deposits. At the Albert Silver Mine, unroofmg of the cover sequences at circa 1600 Ma to 1700 Ma resulted in the incursion of lower-temperature, high-f02 meteoric fluids which remobilized the earlier sulfides and introduced the paragenetically late U-F mineralization."

Jan 1, 1994

By Kenta Suzuki, Toshiya Anami, Daisuke Shimosaka

"In an Al-Mn alloy heat exchanger fin stock, the effect of annealing conditions for as-cast and 0.1%Zr addition on recrystallization behavior is investigated using metallurgical analysis. Refinement of post-brazed recrystallized grains in fin stocks with Zr addition are suppressed for long-time annealing. In 0.1%Zr fin stocks, there was a decrease in the number of fine a-Al(Mn,Fe)Si dispersoids for pinning of sub grain and grain boundary. In addition, relatively homogeneous distribution of Al3Zr dispersoids was observed with increasing annealing time in as-cast. Homogeneous distribution of Al3Zr dispersoids can have a major effect on pinning of sub grain and grain boundary during brazing heat treatment. The homogenous distribution of fine dispersoids prior to brazing heat treatment is effective in causing the suppression of refinement of post-brazed recrystallized grain structure in aluminum alloy fin stocks.INTRODUCTIONAl-Mn based alloys are widely used as fin stocks in automotive heat exchangers because of their superior mechanical properties, braze ability, sagging and so on. In particular, coarsening of recrystallized grain structure is beneficial to avoid erosion, and achieve excellent sagging resistance (Lee, Yoon, Kim & Jung, 2002). For resisting grain coarsening, the alloys should contain a dense and homogeneous distribution of fine dispersoids to retarder crystallization (Humphyreys& Hatherly, 2004). It has been demonstrated that addition of Zr to Al-Mn alloys can shift recrystallization to higher temperatures because of the distribution of fine Al3Zr dispersoids in matrix(Pokoba, Cieslar& Lacaze,2012). According to Tohma, Asanoand Takeuchi (1987), coarsely recrystallized grain structure was obtained in 3003alloy with Zr addition after heat treatment. However, fine Al3Zr dispersoids are usually heterogeneously distributed because of segregation during casting and low diffusion rate of Zr in aluminum. Therefore, a homogeneous distribution of Al3Zr dispersoids can be achieved through long-time precipitation annealing(Jia, Hu, Forbord& Solberg, 2008)."

Jan 1, 2018

By Ralph L. Rutherford

Introduction During the past twenty-five years we have seen considerable exploration for oil on the plains of southern and east-central Alberta. This exploration has to some extent gone on in cycles, with periodic starts, stops, and occasionally some reversals. Each major attempt is usually supplemented by the application of some new method of exploration and, following each period of exploration, drilling tests are made. Whereas oil-bearing horizons are the ultimate objective of these explorations, the preliminary investigation frequently aims at a discovery of structure based on the long accepted belief that accumulations of oil and gas are to a marked degree structurally controlled. At the inception of this general exploration for oil, it was natural that attention should be directed to areas where there was surface evidence of deformation of the underlying strata, but, as the programme progressed, it was found that these surface manifestations of structure were often deceptive when attempts were made to project them to depth, to involve the deeper strata. Drilling of test wells was the only satisfactory method of obtaining exact information.

Jan 1, 1946

By R. C. Gilmore, J. McMack, G. E. Bogin, J. F. Brune, C. DeRosa

"Researchers at the Colorado School of Mines are designing and building a 1:40 scaled physical model of a fully operational longwall coal mine. The purpose of the model is to minimize the occurrence of methane explosion hazards by testing various ventilation strategies and determining optimal methane sensor placement throughout the longwall face. Fluid scaling factors were analyzed using Computational Fluid Dynamics software Ansys FLUENT™ at both full and 1/40th scales. Researchers were able to identify key scaling factors and subsequently developed suitable flow parameters that would maintain full scale accuracy of flow patterns in the 1/40th model. KEYWORDS Coal, Longwall, Methane, Explosion, Scale Model, Ventilation, Fluid Dynamics, Richardson, Gob, Porous INTRODUCTION Mine ventilation systems are a key component for ensuring a safe working environment by introducing fresh air from the surface and diluting explosive gases and hazardous contaminants. This holds true for longwall coal mines where the emission of flammable methane gas from the longwall face as well as the gob can create explosive mixtures of methane and air. Therefore, an effective ventilation strategy can help mitigate the potential for accidents within a mine. Developing an effective mine ventilation system (MVS) requires a detailed understanding of the physics of gas transport and how this relates to specific geometries and obstructions in the face. Researching this phenomenon requires the development of computational fluid dynamics models capable of simulating fluid flow and methane species transport that can be validated through physical experimentation. Unique site conditions determine ventilation layouts for every coal mine. Researchers have designed a 1/40th scaled physical model of a longwall coal face and adjacent gob that includes movable shield supports and a movable shearer with rotating cutter drums that can be adjusted to a variety of ventilation conditions. The proposed work will address the need for an improved Mine-wide Atmospheric Monitoring System (AMS), and provide the ability to link existing MVS models with AMS in real time. By accurately representing the coal face, the gob area and the mining equipment, gate roads and bleeder entries, the scaled model accurately represents all relevant structures, geometry, and dynamic conditions. A Plexiglas cover allows full optical access for sensor equipment as well as visual inspection of the fluid flow and species transport."

Jan 1, 2019

By Y. Chino

Cross-rolling, in which the roll axis is tilted by 7.5 degrees against the transverse direction, was carried out on a commercial magnesium alloy. The (0002) texture intensity of the cross-rolled specimen was lower than that of the unidirectionally rolled specimen. Also, the grain size of the cross-rolled specimen was smaller than that of the unidirectionally rolled specimen. As a result of the Erichsen tests at 433 ? 493 K, the press formability of the cross-rolled specimen was higher than that of the unidirectionally rolled specimen. The high formability of the cross-rolled specimen is attributed to both the reduction in (0002) texture intensity and the enhancement of grain refinement by the cross-rolling.

Jan 1, 2006

"With the globalization of the mining industry, many companies are now seeking to invest in underground diamond mines, with the purchase of small diamond pipes being seen as particularly attractive. However, recent experiences in South Africa have shown that many projects fail due to a lack of awareness of the hazards associated with diamond mining. In this paper three significant hazards are dealt with — mud rushes, block crushing, and implementation of an inappropriate mining method. Measures that assist in the prevention of these three hazards are given.IntroductionFor over a hundred years, South Africa has been seen as the centre of the diamond mining industry, possibly having the largest number of operational underground diamond mines in the world. Despite the fact that this industry has been dominated by large mines of De Beers Consolidated Mines Limited, many small underground mines have operated profitably for a number of years, exploiting diamondiferous fissures and pipes. In the last decade there has been renewed interest in these small operations from international companies. However, many of these projects have not realized their full potential owing to a lack of appreciation of the hazards inherent in the operation of a diamond mine.Hazards Associated with Diamond MiningIn the development of a diamond mine, the mining company must be aware of the hazards associated with diamond mining. There are three main hazards: (1) mud rushes; (2) block crushing; and (3) selection of an inappropriate mining method (not a natural hazard, but a planning induced hazard). Each of these hazards will be dealt with in turn in the following sections."

Jan 1, 2000

By Diego L. Romero, Joy P. Romero

"IntroductionMinerals may be classed broadly as ferromagnetic (magnetite for example), as paramagnetic (attracts to regions of magnetic field convergence) and as diamagnetic (attracts to regions of magnetic field divergence). High-intensity separators are not necessary to separate ferromagnetic minerals from other classes. Rather, low-intensity units that generate fields below 5000 gauss are adequate for this purpose. However, paramagnetic minerals, such as ilmenite, with high magnetic ""attractability"" require fields of up to 10 000 gauss; those with low attractability may require even higher fields. Table 1 shows approximate ranges of field intensities necessary to separate ferromagnetic and paramagnetic minerals from minerals of lower attractability, along with the force with which they are attracted relative to iron in a standardized magnetic field.Uniform magnetic fields, not useful for separators, are generated between flat parallel surfaces; non-uniform fields, useful for separators, arise when at least one of the surfaces is of irregular shape. The diagrams below show how magnetic lines of force align relative to north and south poles.If a particle is placed in a uniform field, it feels no displacing force unless the particle distorts the applied field assymmetrically. This is not the case in non-uniform fields which are required for magnetic separators.Magnetic fields can be generated by permanent magnets (low intensity), by electromagnets (medium and high intensity) and even by superconducting coils (100 000 gauss fields and higher), although the latter are not as yet useful in production environments .The magnetic force of attraction per unit of mass, that acts on a paramagnetic mineral such as hematite, increases in proportion to the strength of the field . Unfortunately, the highest fields attainable with electromagnets is of the order of 20 000 gauss. Fortunately, the gradient of the fie ld (that is, the degree of convergence of magnetic lines of force) is important, because the attractive force per unit mass is proportional to it also . This can be stated:"

Jan 1, 1989

By Jeremy P. Richards

Key inputs are volatiles and heat: Slab dehydration: Breakdown of amphibole and serpentine in hydrated oceanic crust releases fluids into mantle wedge, causing metasomatism.

May 1, 2008

By F. Filzwieser, K. Gamweger

The process of gas purging in molten aluminium has been an industrial practice in Europe for many years. The advantages are a reduction in the hydrogen content and impurities in the melt, as well as a homogenisation of the temperature and chemical analysis in the molten metal. Formerly used lances or impellers are being replaced by porous plugs which are installed at the bottom of the furnace. This special product of RHI Refractories has proven its efficiency in primary melting as well as in die cast, sheet and extrusion plants.

Jan 1, 2004

By F. J. West

This paper deals with Jones & Laughlin Steel Corporation's new Adams mine, near Kirkland Lake, Ontario. After a brief discussion of ore structure, type, reserve tonnages, etc., the main body of the paper discusses the establishment of an open-pit limit based on economic considerations. The method used by J & L to arrive at an economically sound open-pit boundary its outlined fully. Physical limitations to open-pit boundaries are mentioned briefly. The paper concludes with a few remarks on the mining equipment in use and on its productivity

Jan 1, 1966

By H. C. Rickaby

The Bannockburn gold area covers the four townships of Bannockburn, Argyle, Hincks, and Montrose, lying in the western part of the Matachewan district of Ontario (see Figure 1). The geology of these four town-ships was studied by H. C. Cooke of the Geological Survey, in 1917-18, and is shown in his map of the district. In the fall of 1930, a rich gold-bearing quartz vein was discovered in the northwest part of Bannockburn by B. S. Ashley. A prospecting rush followed the discovery; many claims were staked in the Bannockburn area, and, during the summer of 1931, a considerable amount of prospecting was done.

Jan 1, 1932

By J. D. Botsford

Westmin Resources Limited's H-W orebody on Vancouver Island is a copper/lead/zinc massive sulphide deposit that has been in production since 1985. The sulphur content of the ore averages 28% and in some stopes is as high as 53%. Several minor secondary sulphide dust explosions have occurred in development headings and cut and fill stopes, but as yet no known explosions have occurred in blasthole stopes. This pa:per reviews the history of sulphide dust explosions in the H-W Mine, factors contributing to the explosions and the preventative measures taken to control them.

May 11, 1988

By A. C. Bonnier

"INTRODUCTIONI have been asked to make available our method of determining the ""Live Inventory"" within a gravity type thickener. The ""Live Inventory"" being that tonnage compatible with the optimum underflow density that satisfies the process requirements.One prerequisite of the calculations is the proper determination of the final pumpable underflow density. A further requirement is that, prior to shutdown, the thickener has been operated properly, particularly that it has not been operated for storage capacity.Until recently I had few chances to check the method. However, I was most fortunate to have had a recent opportunity covering several months on a 300 ft diameter thickener at a plant in the U.S.A., wherein the method was tested and verified many times. The method proved accurate in that our calculated tonnage checked with the actual dried physical inventory of the drying facility.At the precise moment that the feed to the thickener was shut down, a per cent solid determination was made at the critical place and the tonnage in ""Live Inventory"" determined. Let us say that at the moment the thickener U' Flow solids was 20%. The thickener then was allowed to cperate until the U' Flow solids dropped below 20%, at which time the thickener was deemed to be relieved. Anything much less than 20% was not suitable to the subsequent centrifuge operation.Most large metallurgical thickeners have a configuration of three slopes at the thickener ""bed"". These slopes are dictated by the raking blades and are shown on the manufacturers' erection drawings. The first slope is from the outer periphery and generally takes up a distance of about 60% of the radius, the second slope generally taking up the remaining 40%. Within this 40% area, there is usually another slope taken up by the cone on ""B"" type thickeners or an actual steeper inner slope on ""C"" type thickeners."

Jan 1, 1989

By Robert B. Parsons

"On August 8, 1989, the Minister of Finance released a technical paper which sets out many of the details of a proposed 9% federal value-added tax to be called the ""Goods and Services Tax"". The GST, which is scheduled to be implemented with effect from January 1, 1991, will affect all Canadians in different ways and to varying degrees. The mining industry itself should, by and large, benefit from the new tax.IntroductionOn January 1, 1991, it is proposed that the existing federal sales tax will be replaced by a new sales tax - the Goods and Services Tax (GST). GST will be leviedat a rate of 9% on most goods and services consumed in Canada.How it will WorkThe GST will be a tax on the final consumption of goods and services. It differs from a retail sales tax in that it will be collected throughout the production and distribution chain. However, the net effect of the tax paid on a particular good or service will be equivalent. The example above (next column) illustrates the application of the GST to the production and sale of a chair.Illustration of GST for a ChairEssentially, the total tax will equal 9% of the sale price to the final consumer. However, GST will be collected on the value added at each stage of the production and distribution chain . What will be TaxedVirtually all goods and services will be taxed. Items on which GST will not be charged fall into two categories: tax free and tax exempt."

Jan 1, 1989

By Peter Heine

Diavik Diamond Mines Inc. (DDMI) has treated systems development as an integral part of the construction project when it built Canada?s second diamond mine. Fully aware that the proper collection and processing of operational data is needed to drive business decisions during production and planning, key Performance Indicators (KPIs) were defined to effectively manage operations when the mine went into production. The Production Information Management System (PIMS) allows KPIs to be measured, reported, and transferred to other systems in a reliable and convenient manner. PIMS provides a mechanism to collect real time production data from the various control systems around the site and acts as a tool to ?drill-down? and establish the important cause-effect relationships that impact the value of a KPI. Thus PIMS provides a data collection, storage, management, and an environment in which cause-effect relationships can be analysed and statistically verified. This understanding of the real cause-effect relationships, close to the source of the data and in the context of the operation, can be used to improve both operations and maintenance performance. The PIMS includes the PI Database implementation, its associated external interfaces with the various Control Systems, Cleaning Packaging Weighing System, Environmental System, Enterprise Asset Management (EAM) System, and Diamond Tracking System (DTS), as well as laboratory data collection, custom applications (downtime tracking, data reconciliation) and user clients. The interface with the EAM system provides material flow quantities and equipment availability on which the plant performance reports are based. The transfer of equipment usage to the EAM system is fed into the maintenance notifications and work orders functionality in the EAM. The environmental system interface provides the mechanism for capturing water consumption data required to generate the various regulatory reports. The interface to the cleaning-packaging-weighing system provides the mechanism for capturing batch data for transfer to the DTS for diamond product tracking at the production splitting facility in Yellowknife. The PIMS lab application provides a means of getting sample data into the system for critical metallurgical metrics, and the data reconciliation application provides a means of manually verifying the data before it is published or passed onto other systems.

May 1, 2003

By Angela L. Paveley

Economic viability of base metal mining is complicated by a volatile market that can cause fluctuations in the growth and stability of the mining industry. Nickel is mined primarily for use in manufacturing industrial stainless steel and plating materials. It is essential that nickel production be sufficient to respond to current and future market demand. A Post-Pillar cut and fill mining complex is currently producing nickel sulfide in Northern Manitoba. From 2006 this area has shown a steady increase in the annual production, rising from 11 million pounds to 25 million pounds in 2010, and accounting for 33% of the total production for the Manitoba Operations. It is expected that fine-tuning the mining process can safely enhance ore recovery, improve production consistency, and increase economic viability of the deposit. The Post-Pillar Optimization study was initiated by the local technical and operational departments at the mine and analyzed from July 2010 to March 2011. The purpose of this study was to determine if portions of non-recoverable pillars can be slashed without jeopardizing pillar strength. This ideal case would optimize ore recovery and reduce variability in the ore mining rate. Numerical modeling and geo-mechanical material properties analyses, completed by the rock mechanics group, define the maximum drift width at 32 feet and the minimum pillar width at 18 feet. Thus, it was suggested that up to 3 feet could be slashed from two sides of the standard 24 foot pillars without damaging ground integrity. The field data collected indicates that additional ore could be recovered without compromising the safety of the workplace and the integrity of the complex. Consequently, technical and operational groups work jointly to achieve pillar optimization. Approximately 500,000 pounds of nickel was extracted from the complex via pillar optimization from July 2010 to March 2011. Economic analyses show the pillar optimization method developed for the mining complex is a proven, value-added opportunity. The mining complex remains a safe workplace and has retained ground integrity.

Nov 1, 2011