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By P. Chryssanthakis

"The aim of this study is to give a better understanding for the behaviour of the composite material RRS and the synergy effect of its components while an excavation face advances during tunneling. The lower part of the Q-system scale (i.e. Q-values of 0.4 or less for a tunnel span of 10 m) is commonly used for tunnel applications in softer rock formations. This is implied in the updated Q-chart, where the dimensioning of rock support by using Reinforced Ribs of Shotcrete (RRS) comprises the use of fiber reinforced shotcrete, S(fr), rock bolts and shotcreted beams reinforced with steel rebars. The newest part of the lower part of the Q-chart gives more information on required support compared to older Q-system versions. The RRS can be described as a three part composite material with the 3rd component being the reinforced concrete beam (with no fibers) and with steel rebars that are placed in groups and sprayed with pneumatically applied shotcrete in layers. The RRS usually have a total thickness varying between 0.20 and 0.50 m and a width between 0.25 and 0.60 m respectively. They are placed at different distances along the tunnel axis depending on the rock mass quality.In this study, an effort has been made to simulate RRS in a numerical code and to study its behaviour in a real case study. A double tube, triple lane tunnel in weathered tuff has been chosen as reference material for testing RRS under changing load. This was done by writing a FISH subroutine which is implemented in the discontinuous numerical code Universal Distinct Element Code (UDEC) that takes into account the characteristics of the reinforced beam (height, width, number of steel rebars, and spacing) in the calculation process. A rather extensive parametric study has been run by using the same key input rock mass parameters and in situ stresses (?H/?v = 0.5), and changing only the RRS key input parameters in order to simulate the changing loads during the face excavation process in tunneling. The critical part of this numerical modelling work that is under investigation in this study, is the period just after the excavation: i.e 4 hours; 16 hours after excavation; and finally after the complete curing (28 days) of the cement based components. The RRS are installed in three consecutive steps as follows: a) the application of S(fr) on the rock surface in order to even it up for the RRS application; b) radial bolting; and c) installation of the reinforcing steel rebars, that form the reinforced beam.The results show that: a) the S(fr) is almost overloaded in the first 4 hours after application in both tunnels; b) on the S(fr) and steel rebars, the stresses, axial and shear loads, as well as moments are decreasing after 16 hours and 28 days; and c) the bolts loads are increasing with time. The observed reduction in stresses and loads in both the S(fr) and reinforced beam is surprising. A possible explanation is that tunnel arches are self-supported to a lesser extent as time progresses due to redistribution of stresses in the nearby rock mass through the radial bolts. The loads in radial bolts are increasing by almost 25%. This can be seen from the overall results as we observe an increase in maximum principal stresses, displacements, shear displacements along joints and hydraulic apertures compared to tunnel baseline that has no support of any kind."

Jan 1, 2015

By W. S. Dyer

Introduction In northern Ontario, refractory clay is found on four rivers of the James Bay watershed: the Abitibi, the Mattagami, the Missinaibi, and the Moose. The clay all belongs to the same geological formation ( the Mattagami of Lower Cretaceous age) , and occurs within a structural depression or 'basin', the boundaries of which have never been defined but which appears to cover at least 1,500 square miles of territory. The recently constructed James Bay extension of the Temiskaming and Northern Ontario railway crosses the northeast end of the basin at the Onakawana lignite field, which by rail is 126 miles north of Cochrane, 605 miles north of Toronto, and 60 miles southwest of Moose Factory. Smoky Falls, the northern terminus of the railway owned by the Spruce Falls Power & Paper Company, Limited, is 7 miles south of one other point in the basin, i.e., the outcrops of refractory clay, sand, and kaolin at the foot of Long rapids on the Mattagami river. Smoky Falls is 50 miles north of Kapuskasing. In a very early report(l) , Dr. Robert Bell, of the Geological Survey of Canada, described '"light coloured marl in horizontal beds" from the Missinaibi river, and noted that the lignite also occurring in the river was probably :associated with the marls. This was undoubtedly the Cretaceous refractory day. Other early writers noted the occurrence of fire-clays, but it was not until Joseph Keele(2), of the Geological Survey, visited thee region in 1919 and studied the clays that their real significance was known.

Jan 1, 1933

By S. Amira

The corrosion behavior of high pressure die-cast and thixocast AXJ530 magnesium alloys has been investigated in 0.05M NaC1 solution at pH 6.0 using potentiodynamic polarization tests, electrochemical noise (EN) technique, electro-chemical impedance spectroscopy (EIS) and scanning reference electrode technique (SRET). The behavior of die-cast and thixocast specimens were compared using each of these techniques and the results discussed. Further tests have been carried out with die-cast AZ91D alloy to better compare and interpret the results. Experiments indicate that the thixocast specimens of AXJ530 alloy have a better corrosion resistance than those of die cast alloy in neutral solution.

Jan 1, 2006

By W. A. Padgham, H. Helmstaedt

Field evidence for current hypothe e about age and kinematic ignificance of gold-bearing hear zones in the Archean Yellowkni fe greenstone belt is reviewed , and it is concluded that major disagreements between previous workers are a direct result of differences in stratigraphic and tructural in terpretations of the Yellowknife Supergroup. Although goldbearing hear zone appear to be confined to the mafic volcanic pile of the Kam Group. it can be shown that shearing affected all supracru tal rocks, including the Jackson Lake Formation. now con idered to represent the youngest unit of the Yellowknife Supergroup. tructural ob ervations are incompatible with the hypothe is that the hear zones represent loci of ynvolcanic gravity sliding but are consistent with earlier conclu ions that shear zone development commenced with rotation of the volcanic pile and continued as re ult of lateral shortening broadly overlapping with the emplacement of granitoid batholiths. Shear Zones are common throughout the entire green tone belt. yet productive zone are confined to the Yellowknife Bay Formation of the Kam Group and localized where flow abut with a high angle again t the contact of the We tern Plutonic complex. However. no obvious tructural and lithological features have been recognized that are more favorable for gold deposition and distinguish the shear zones and flows of the area around the mines from those of other parts of the greenstone belt. The model that gold wa transported by metamorphic solutions and that hear zones were the firs t-order control for gold deposition provides no explanation for the trong localization of the depo it . As porphyries with elevated gold contents are present in and near ome of the mines. the possibility that gold was deposited from hydrothermal system around fel ic intrusion representing early phases of the Western Plutonic complex should be given erious consideration.

Jan 1, 1986

By J. W. Reynolds

Introduction The Sullivan mine, at Kimberley, B.C., is the principal source of ore for the Consolidated Mining and Smelting Company of Canada, Limited. Current production amounts to about 2,500,000 tons of lead-zinc ore a year. With approximately 1,600,000 feet of percussion drilling and 700,000 feet of diamond drilling being carried on each year, any improvements in drilling practice are important. Testing of new equipment and drill bits is a major function of the Testing Department at the mine. Tungsten carbide bits have been the subject of many tests since 1947 and have been used in operations since 1948. This paper details with the methods of testing and gives comparative data on performance and costs for tungsten carbide bits as compared to steel bits. Operational use of tungsten carbide bits started in April, 1948, and the extent of application has increased considerably since that time. The scale of employment is illustrated in Table I, which also shows other statistics on the use of carbide bits. Up to the present time eighteen types of carbide bits or tipped steel, as made by six different manufacturers, have been tested. In general, one supplier's bits have been used in operations, but some large-scale operational tests have been carried out with other types. The types tried are shown in Table II. To date they have been, the subject of 33 tests, covering the destruction of 804 bits over an observed footage of 42,586 feet.

Jan 1, 1951

By D. H. Ryan, B. Abdul, M. Pernechele, E. Asselin

Hydrometallurgical processing of sulphide concentrates at medium temperature (150°C) produces residues, which contain valuable metals (Cu, Ni) as well as sulphur and iron bearing minerals and phases. The low solubility of iron during the medium temperature processing of sulphide ores can favour the formation of poorly crystalline, nano-scale iron oxide/oxyhydroxide phases. A better understanding of the formation and structure of these iron precipitates may elucidate key factors that would ultimately result in lower valuable metal losses and more stable leach residues. Residues from two medium temperature leach processes were characterized by Mössbauer Spectroscopy. Some portions of the Mössbauer Spectrum were suspected to be linked to jarosite but could not be positively identified as such. There was a broad range of disorder and substitution present in the material and solely attributing it to jarosite proved difficult. Various synthetic jarosites with Cu substitution were precipitated for Mössbauer analysis. These were then characterized by Quantitative X-Ray Diffraction (QXRD), Scanning Electron Microscopy (SEM), Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) and Mössbauer Spectroscopy. The Mössbauer Spectra of the synthetic jarosites is compared with that of the residues from medium temperature (150°C) sulphide concentrate leaching.

Jan 1, 2014

By X. Cao, J. J. Jonas, Wanjara. P., J. Gholipour, E. Dalgaard

The linear friction welding (LFW) behaviour of near-ß titanium alloy Ti-5Al-5V-5Mo-3Cr (Ti- 5553) was investigated. Microhardness measurements were performed in order to evaluate the mechanical properties of the welded material. The linear friction welded (LFWed) Ti-5553 was examined with optical microscopy and scanning electron microscopy (SEM) to evaluate the microstructure’s response to the thermomechanical conditions. Characterization of the welds included analysis of the microstructural features of the weld region and thermomechanically affected zone (TMAZ) in relation to the parent material.

Jan 1, 2010

By A. Mcdonald, F. W. Breaks, T. F. Morris, S. A. Averill, D. C. Crabtree

Gahnite, a zinc-bearing spinel, is a resistate mineral that may be used as an indicator mineral of polymetallic deposits in high-grade metamorphic terrain. The Ontario Geological Survey recently completed sur?cial mapping and sampling programs in the Separation Lake area of north-western Ontario and Kinniwabi Lake area of northeastern Ontario in which gahnite was recovered from samples of sur?cial sediments. Ternary plots of the composition (ZnO, MgO, FeO[t]) of gahnite recovered from these sur?cial studies reveal three distinct groups: Group 1 is characterized by low (< 1 wt%) MgO values; Group 2 by higher (>1 wt%) MgO values; and Group 3 by higher FeO(t)values than Groups 1 and 2. The composition of in situ gahnite recovered from volcanogenic massive sul?de mineralization, Zn-rich Sedex-type mineralization and peraluminous rare-element mineralized granite and pegmatite also was determined. The composition of the gahnite obtained from sur?cial samples was compared with that of in situ material. Gahnite from the peraluminous rare-element granite and pegmatite overlapped very well with sur?cial gahnite of Group 1. Gahnite from volcanogenic massive sul?de mineralization and Sedex-type mineralization overlapped well with sur?cial gahnite of Group 2. These results suggest that determination of gahnite composition in indi-cator mineral surveys may be useful in exploration programs when assessing the mineral potential of a region.

Jan 1, 1997

By Nick Hazen

Many successful actions are required to bring a profitable extractive metallurgical operation into production. Competent process development performed within the project development schedule increases the chances of obtaining project financing and decreases the risk of engineering design errors being built into the commercial plant. The general sequence of steps in process development is well known: technology review, desktop studies, scoping studies, prefeasibility, and so on, with an increasing requirement for experimental evidence as the studies advance. This paper suggests principles for guiding process development work so that the efforts stay on track toward a smooth startup and a profitable commercial operation. It emphasizes closely aligning the research with the corporate goals of the mining company management, understanding the mineralogy and variability in the deposit, and guiding by flowsheet and material balance. Examples of hydrometallurgical process development leading to the early use of solvent extraction in the mining industry are given.

Jan 1, 2014

By A. Mcdonald, F. W. Breaks, T. F. Morris, S. A. Averill, D. C. Crabtree

Abstract-Gahnite, a zinc-bearing spinel, is a resistate mineral that may be used as an indicator mineral of polymetallic deposits in high-grade metamorphic terrain. The Ontario Geological Survey recently completed surficial mapping and sampling programs in the Separation Lake area of northwestern Ontario and Kinniwabi Lake area of northeastern Ontario in which gahnite was recovered from samples of surficial sediments. Ternary plots of the composition (ZnO, MgO, FeO[t]) of gahnite recovered from these surficial studies reveal three distinct groups: Group 1 is characterized by low (< 1 wt%) MgO values; Group 2 by higher (>1 wt%) MgO values; and Group 3 by higher FeO(t) values than Groups 1 and 2. The composition of in situ gahnite recovered from volcanogenic massive sulfide mineralization, Zn-rich Sedex-type mineralization and peraluminous rare-element mineralized granite and pegmatite also was determined. The composition of the gahnite obtained from surficial samples was compared with that of in situ material. Gahnite from the peraluminous rareelement granite and pegmatite overlapped very well with surficial gahnite of Group 1. Gahnite from volcanogenic massive sulfide mineralization and Sedex-type mineralization overlapped well with surficial gahnite of Group 2. These results suggest that determination of gahnite composition in indicator mineral surveys may be useful in exploration programs when assessing the mineral potential of a region.

Jan 1, 1997

By S. Kelebek

Batch flotation tests were carried out using samples from stockpiles that were up to 1.5 months old as well as fresh samples oxidized in the lab for up to six months. Head grades and size distributions of samples were equalized whenever possible. The samples from stockpiles and oxidation experiments produced inferior nickel grade-recovery compared to the fresh sample. The poorer grade-recovery performance was attributable to two factors. First, a significant dilution effect was observed due to complete flotation of pyrrhotite. Secondly, the same stockpiling conditions caused nickel losses that were attributable to non-floatability of some pentlandite. Application of a high pH of 10 compared to the regular pH of 9.2 slowed down pyrrhotite flotation kinetics, but was not able to prevent complete flotation after 8 minutes. The samples oxidized in the lab did not match full characteristics of stockpile samples. They provided somewhat better selectivity for pentlandite. Some correlations were observed on a qualitative basis between surface characteristics such as elemental sulphur formation, activation and flotation behaviour. Oxidation conditions, which induce floatability on pyrrhotite while causing incremental loss in pentlandite floatability appear to be the root cause of difficulties in the processing of oxidized forms of these ores.

Jan 1, 2006

By J. Aiello

"Introduction Byron Creek Collieries Limited Corbin mine is located in southeastern British Columbia approximately 180 air kilometres southwest of Calgary (Fig. I), twenty four kilometres south of Highway No. 3 via a newly constructed provincial road (Fig. 2). The development of the area began July 30, 1905, when D.C. Corbin, a prominent businessman from the northwestern U.S., and his associate E.J. Roberts first visited the site of Coal Mountain on horseback. Coal was in great demand by railways and other industrial users, so the Corbin Coal and Coke Co., after acquiring 6,000 hectares of land in the area, began to develop a mine. Mr. Roberts was responsible for the construction of the 22-kilometre rail spur, the Eastern British Columbia Railway, which joined the mine to the CPR main line at the McGillivray Loop. Rail access to the mine and its developing community, Corbin, B.C., was completed in September 1908, the same year that the first underground mine began production. The Corbin Coal and Coke Co. operated six mines on Coal Mountain (Fig. 3) and production from 1908 to 1930 inclusive totalled 2,120,800 tonnes. This production was allocated to the mines as follows:"

Jan 1, 1985

By B. Fang

Electrochemical behavior of an X-80 pipeline steel, including frequency-sweep electrochemical-impedance spectroscopy (EIS), time-sweep EIS at a constant frequency and open-circuit potential (OCP) monitor, was investigated using four-point bending specimens subjected to a stress-corrosion cracking (SCC) test in a near-neutral pH environment, The capacitive loop became smaller with test duration, revealing an increase in the corrosion rate, The resistance obtained in the constant-frequency EIS test showed two regions, of which the region with a remarkable decrease in resistance transformed into a region of slow decrease, whereas the capacitance increased with test time indicating that iron dissolution was fast at first, and then a corrosion product or film formed and covered the surface, leading to the pitting formation.

Jan 1, 2005

By Patrick Moore

In 1971 the government of British Columbia issued a permit for the Island Copper Mine to commence disposal of 33,000 tons per day of mine tailings into Rupert Inlet, a marine fjord on the northwest coast of Vancouver Island. There was considerable controversy surrounding the development, public hearings were held, and as a requirement of the permit the company was obliged to carry out a comprehensive environmental monitoring program. The results of this program provide a thorough assessment of the environmental impact of submarine tailings disposal over the 24-year life of the mine. Following closure in December, 1995, the monitoring program continued for three years to determine the extent of marine ecosystem recovery and re-colonization. It is apparent from the findings of the monitoring program that the mine tailings were dispersed more widely than was originally predicted. It is also clear that widespread heavy metal contamination has not materialized. In retrospect it appears that submarine tailings disposal has resulted in far less severe environmental impacts than if the alternative of land disposal had been adopted. This review highlights significant aspects of public policy decision-making, design of environmental monitoring programs, and questions of interpretation of monitoring program data.

May 1, 2002

By P. Bakke

Following extensive R&D efforts, Hydro Magnesium has launched a new alloy series with remarkable combinations of properties. The AE alloy family is based on additions of aluminium and rare earth elements to control mechanical properties, including elevated temperature creep strength. By combining these alloying elements with manganese additions, high purity alloys with outstanding corrosion performance are defined. A basic philosophy behind the developments has been to simultaneously approach all the critical issues related to developing a commercial material. Apart from the obvious requirements for material properties, the critical issues relate to die casting performance, as well as alloy production, recycling and environmental compatibility. Some of the important elements related to alloy production and recycling are addressed in the present paper.

Jan 1, 2006

By F. Chiesa

Experimental results on thin and thick castings poured in aluminum A356 and magnesium AZ91E by the low pressure permanent mold process have been compared to the result of filling simulations for thin and thick castings. If the results of modeling is reliable when the liquid remains above the liquidus temperature, this is no longer the case when partial solidification occurs. The visco-elastic behavior of a partially solidified liquid is difficult to put into equation as it depends on the amount of shear it has been been subjected to. Attempts to predict misruns with a commercial software has been proven to be very difficult if not impossible; divergence of the numerical solution has been observed unless prohibitively long computing times are used. In order to overcome these difficulties from a practical standpoint, a simple method is proposed which consists in tracking the temperature of the advancing liquid metal front so as to make sure it will always be above so-called `Misrun Critical Temperature&apos; (MCT) determined experimentally for thin and thick aluminum A356 and magnesium AZ91E castings. If the liquid metal front falls below this temperature, a cold-shut or misrun is likely to happen at this location. The values of MCT for thin and thick in aluminum A356 and magnesium AZ91E were determined experimentally on misrun castings of extreme geometries (a thin 2.5 mm wall cover and a 6mm to 25 mm thick bell housing). MCT was found to be lower for magnesium AZ91E and for the thicker castings.

Jan 1, 2011

By S. Zekovic

"The paper gives an overview of the economics condition and strategic business challanges of the mining&metallurgy sector and their possible impact on the future development of the Bor basin of copper in Serbian part of Danube Region. Economics and strategic challanges in the mining& metallurgy complex are emphasized by world economic and financial crisis. An analysis of strategic challanges is undertaken by application of a comprehensive development framework approach. Paper indicates that an economics and evaluation of possible impacts of constraints and challenges for the development of Bor basin shows that it must be included in corporative decision, local and regional plans.INTRODUCTIONRisks are characteristic of every strategic development and business decision-making, so their successful management should be a part of the development strategy of the corporation, especially longterm. Due to the growing uncertainty in the general socio-economic environment, “risk management”, risk insurance, risk control, risk culture, risk optimization are frequently talked about. Among the key risks at a corporate level are the financial risks and risks of the regulative framework, especially in the field of environment and land use. In both cases, it is a question of external risks, which the companies need to relativize and successfully manage. Some companies pay more attention to production risks and search for better solutions in that domain which is not enough (Ernst&Young, 2008). Strategic business risks appear mostly on the macro-economic level, from where they should be” transferred” onto the level of sector economics and action level in corporations. Risk management include transferring the risk to other parts, avoiding the risk, preventing hazard, reducing the negative effect or probability of the risk, accepting some or all of the consequences of a particular risk.The research has included perspective and the general market trend and market positioning of the production and copper processing complex in the world; the impact of the requirements and strategic goals of the EU Directive and Kyoto Protocol on the institutional and other adjustments important for business in this sector; the impact assessment of the regulations important for business in the mining and metals sector, and case study of economics and challenges for the development of mining and metallurgy sector in the Bor basin of copper in Serbian part of Danube region. The analysis has included the identification and assessment of the global challenges on the future development of the copper complex in the miningsmelting basin Bor. Presented results in the paper are part of the research project “Sustainable spatial development of the Danube area in Serbia"" (No. 036036), financed by Ministry of Education and science of Republic Serbia."

Jan 1, 2012

By Peter Broad

"Extracting any metal, especially specialty metals and rare earth elements, requires an in-depth analysis of the costs and potential revenue as well as a due diligence study of other stakeholder interests. Rare earth projects are generally in the billion dollar US range or above, and thus failure to accurately predict any loss of revenue caused by impurities within the product or additional effluent treatment costs can destroy an otherwise viable study. Two prime sources of input impurity are considered: impurities in the material feed and from reagents. The effect of these impurities factor on both the product (in reduced revenue) and on residual “tailings” that may incur additional unforeseen costs.INTRODUCTION“Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident” – Arthur SchopenhauerThe era of unscoped, unbudgeted construction ended about 150 years ago. Today’s engineer must design with confidence; but do so amidst proprietary secrets and unfamiliar pollutants, which present a myriad of interesting challenges. Is it possible to build a viable rare earth plant to a realistic budget, without destroying that which we cherish? Some see this as contradictory but in reality it is the only viable option.WHEN GOOD PROJECTS FAILWithout rare earths the Copenhagen agreement might be null and void. Running a wind turbine with a 30 tonne conventional magnet requires some hefty engineering and prohibitive investment. Despite their ‘Green metal’ applications, production of rare earths have created environmental nightmares, as Folger stated in 2011 when visiting Baotou, or has Jaing Mainheng who has been quoted by Ambrose Evans-Pritchard 6 Jan 2013. This comment is not a criticism of China; the details are from a 2012 white paper published by the Chinese Government that initiated a $6 billion environmental clean-up. Nor is China unique; other plants have had problems as well. There were toxic leaks in the 1990s from Mountain Pass, and the Mitsubishi Bukit Merah Plant (built in Malaysia in 1958) required a $100 million clean-up."

Jan 1, 2016

By G. G. Eichholz

SUMMARY RADIOACTIVE dynamite has been prepared by introducing a small amount of antimony-124 into the explosive. Test work is described on the effectiveness of this tracer, on radiation levels in its neighbourhood, and on different methods of .application. Factors determining the choice of isotope, amount of activity, and overall cost of this process are discussed. INTRODUCTION Instances are known in which dynamite remains unexploded in drill holes in mining operations. Usually such &apos;bootlegs&apos; are easily located by inspection of the face and the powder is removed before subsequent drilling is started. Occasionally, however, serious accidents occur because workmen drill into an undetected piece of dynamite. In order to avoid such accidents it was suggested that a different method of location might be tied, such as that afforded by the use of radioactive tracers. This paper describes some experiments that were carried out under the auspices of the Department of Mines and Technical Surveys, with the active co-operation of Canadian Industries Ltd. and Canadian Refractories Ltd., to test the feasibility of such a scheme.

Jan 1, 1957

Most of automotive magnesium applications are presently produced by high-pressure die casting processes, For further expansion of the alloy usage in automobiles, novel-manufacturing processes needs to be developed, In this study, squeeze casting of AM50 alloy was carried out using a hydraulic press with an applied pressure of 70 MPa, Tensile properties and fracture behavior of the squeeze-cast AM50 were characterized in comparison with the die cast counterpart, The squeeze-cast AM50 alloy exhibits virtually no porosity in the microstructure evaluated by optical microscopy, The results of tensile testing indicate that the improved tensile properties for the squeeze-cast samples over the conventional high-pressure die-cast parts, The analysis of tensile behavior shows that the strain-hardening rate during the plastic deformation of the squeeze-cast specimens is constantly higher than that of the die-cast specimens. The SEM fractography evidently reveals the ductile fracture features of the squeeze-cast alloy AM50.

Jan 1, 2005