Search Documents

By O. Moselhi

Material can be seen as the fuel needed to execute the project from inception to completion. Material installed provides good indicators of progress achieved onsite vis-a-vis project schedule performance. It correlates well with the role of the schedule performance index (SPI) of the earned value method (EVM). Material is recognized to have a significant impact on achieved progress for physical completion of project activities. This paper presents a study on the development of material status index (MSI) in support of the EVM. Unlike the SPI, the newly developed index account for the criticality of project activities. This is carried out considering the total float of each activity, percent float (i.e. the ratio of float to activity duration) and the total float of the path on which the activity is located. MSI, can independently and jointly with SPI provide root causes behind problems encountered during project execution. In turn MSI can reveal material related factors behind the performance detected by joint interpretation of the two indices. MSI serves to provide added value in alerting management to take corrective actions. While SPI and MSI may have different values, they can jointly augment and enrich the captured project status based on EVM. To demonstrate the capabilities of the developed MSI method, it is implemented on a case study. The case encompasses the construction schedule of a hydro power station constructed in northern Quebec. Different scenarios are adapted from the real case to demonstrate a set of practical aspects of the developed index. The results generated from the analysis of the case study illustrate the useful features of MSI beyond those of the traditional SPI on two fronts; causation and the considerations of criticalities of actives.

Aug 1, 2013

By K. Oishi

We have developed a 76Cu-3Si-21Zn alloy "ECOBRASS®" containing no lead. When 3% Si is added to a 78Cu-22Zn alloy, kappa and gamma phases participate uniformly in the alpha matrix. When being machined, stress concentrates on these hard phases, namely kappa and gamma, and thereby lowering the required cutting force and yielding segmentalized chips without lubricant. Kappa and gamma phases transform into beta phase under high temperature, which makes it easier to extrude and/or forge the alloy. When 0.08% P and 50 ppm Zr are co-added, the grains of ECOBRASS® castings are refined significantly to become as small as several dozens of micrometers. The grain refinement by the co-addition of P and Zr improves castability, tensile strength and elongation of ECOBRASS® castings. Meanwhile, the lead leachate from an ECOBRASS® water meter, field-tested in pH 6.8 drinking water for one year, was less than 5 ppb without correction. No indication of dezincification corrosion was observed, either. ECOBRASS® is equally suitable for rods, forgings and castings, and makes it possible to produce a complete set of plumbing parts (valves, faucets, etc.) by its own. This way, not only improving recyclability, ECOBRASS® also realizes size and weight reduction due to its good corrosion resistance and high strength.

Jan 1, 2007

The tensile test results of as-cast A356.2 grain-refined alloy castings show that the tensile strength can be improved by strontium modification (`SrM'), superheating at 900°C OM, and melt thermal treatment of the Sr-modified alloy melt (`SrMTT'). Both SrM and SrMTT processes can greatly improve the ductility (percent elongation) of the as-cast alloy. During solution heat treatment at 540°C, eutectic Si particles undergo fragmentation, spheroidization, and coarsening, thereby affecting their morphology. The effects of solution heat treatment on the tensile properties of the variously treated A356.2 alloy castings can be summed up as follows: the yield strength of the castings is significantly improved after 8 h solution heat treatment due to the precipitation of Mg2Si, after which it remains more or less the same with the further increase in solution treatment time up to 80 h; the ultimate tensile strength is also greatly improved within the first 8 h of solution heat treatment and then remains at the same level thereafter, up to 80h of solution treatment. The improvement in UTS is attributed to Mg2Si precipitation, dissolution of Si within the aluminum matrix, and changes in the Si particle morphology (spheroidization). The ductility of the as-received grain refined non-modified (`NM'), grain refined and superheated at 900°C (`SH'), and melt thermal-treated grain refined (`MTT') A356.2 alloy castings can be improved considerably with solution heat treatment e.g. from ~6% in the as-cast non-modified casting to ~10% after 80 h solution treatment.

Jan 1, 2011

By Dan Miners

"This presentation will provide an overview and understanding of Mine Safety and Health Administration (MSHA) and Ontario Regulations for Mines and Mining Plants. It includes discussions on the history and practical development of the standards and an overview of engineering best practices from a construction, maintenance and operational viewpoint. INTRODUCTION Ontario is one of the safest mining jurisdictions in the world and has some of the most comprehensive regulations for the construction, operation and maintenance of a mine. In the USA, several operators have adopted some or all of the practices prescribed by the Ontario Regulations as an internal procedure. Experience has demonstrated that these plants are indicating less unplanned downtime and fewer issues with MSHA inspectors in their hoist plants. HISTORY AND THE REGULATIONS Both Canada and the USA have had some form of laws governing the operation of mines since the late 1890s. The paths of legislation have run in reasonably parallel lines, continually improving the health and safety conditions in the mining industry. Ontario Mine Health and Safety In the 1970s the accident rates in mining were higher than any other industrial sector; this prompted a Royal Commission on the Health and Safety of Workers in Mines (the Ham Report). The recommendations of this report, published in 1976, generated several changes in the regulations regarding worker safety in mines. Following the release of the Ham report, the Occupational Health and Safety Act (OHS) was passed by the Legislature in 1978. The Act is a set of comprehensive laws governing almost all Ontario workplaces, and it replaced separate laws governing different industrial sectors. OHS is enforced by the Ministry of Labour (MOL), and this discussion will focus specifically on Ontario’s Occupational Health and Safety Act, R.R.O. 1990, Regulation 854, Mines and Mining Plants, Part X Mine Hoisting Plant (Ontario Regulations). USA Mine Health and Safety A coal mine explosion in West Virginia and medical studies on occupational disease led to the 1969 Federal Coal Mine Health and Safety Act (Coal Act). The Coal Act was the most comprehensive and stringent Federal legislation governing the mining industry to date. The Mining Enforcement and Safety Administration (MESA) was formed, following the 1973 Act, as a new departmental agency to assume the enforcement of safety and health in mines. The Federal Mine Safety and Health Act of 1977 (Mine Act) transferred enforcement responsibilities from the Department of the Interior to the Department of Labor and named the new agency the Mine Safety and Health Administration (MSHA). This agency enforces the Code of Federal Regulations (CFR), and this discussion refers to CFR Title 30 Mineral Resources, Chapter I Mine Safety and Health Administration, Department of Labor, Subchapter K—Metal and Non-metal Mine Safety and Health (MSHA)."

Jan 1, 2019

By Antonio Fontana

"Environmental problems encountered with the use of diesel equipment in underground mining operations are discussed. The concept and procedure o implementing the Health Effects Index equation as a means of quantitatively assessing an underground working environment is outlined and sample calculations are present ed. Advantages and disadvantages of utilizing this method are also discussed.IntroductionWith the introduction of diesel-powered mining equipment in the 1960s there arose several question s for the environmental engineer to consider. These included: 1. What are the constituents of diesel exhaust and how can they be detected and evaluated?2. What are the toxicities and long-term health effects of these constituents?3. What is the ventilating volume required to maintain the concentration of these constituents below toxic levels?Diesel engines are a class of reciprocating, internal combustion engines in which relatively high compression ratios are used to generate high air-charge temperatures, which cause ignition of fuel to occur spontaneously. Ideally, perfect combustion of the fuel would produce an exhaust consisting solely of nitrogen (N2), water (H2O), carbon dioxide (CO2) and oxygen (O2). However, because no combustion process is perfect, relatively small quantities of imperfect-combustion products, or pollutants, are also generated. These include hydrocarbons (HC), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), carbon (C) or soot, and sulphur dioxide (SO2).Currently, the Regulations for Mines and Mining Plants, made under the Occupational Health and Safety Act (Section 176), stipulate that weekly tests shall be made to determine the carbon monoxide (CO) concentration in the undiluted exhaust and at the operator's position, and the nitrogent dioxide (NO2) concentration at the operator's position. Also, the aldehyde (as HCHO) concentration in the atmosphere, at the operator's position, is to be measured at least every three months. Threshold limit values (TLVs) have been established for each of the three combustion products, and each is regarded as a separate entity. Consequently, this does not allow for consideration of interactions and possible synergistic effects between the various exhaust components."

Jan 1, 1982

By G. L. Palmer

"In 1986, anomalous sampling results for heavy minerals were obtained at various sites in Namaqualand on the west coast of the Cape Province. Drilling in 1987 at Graauwduinen penetrated up to 35 meters of heavy mineral-bearing Tertiary sands which extend several kilometers inland from the coast. The heavy mineral suite includes ilmenite, rutile, leucoxene, zircon and monazite, along with gamet, pyroxene and amphibole. Three deposits are recognized, two of which comprise the resource to be mined by Namakwa Sands Limited, a recently formed Anglo American Corporation subsidiary company.Mineable reserves in excess of 500 million tonnes have been delineated, sufficient to sustain mining for over 35 years at projected production rates. During the feasibility study, on-site investigations included test mining at various sites to assess rnineability and to provide material for metallurgical testing in a pilot plant located at the site. llmenite produced at the mine will be smelted at a new facility to be built at Saldanha Bay. Saleable products comprise titania-rich slag, pig iron, zircon and rutile.During the exploration phase, company environmental guidelines were established and monitored. The feasibility study incorporated a Class 1 Environmental Impact Report, the contents of which were made public following the principles of the Integrated Environmental Management legislation."

Jan 1, 1994

By N. Afrin

The microstructure and tensile properties of AZ31B-H24 magnesium (Mg) alloy after friction stir welding (FSW) were evaluated. The grain size was observed to increase from approximately 5 µm to about 9 µm after FSW. The obtained Hall-Petch type relationship showed a strong grain size dependence of the hardness values. While the FSW led to about half of the yield strength of the base magnesium alloy, the ultimate tensile strength after FSW could reach about two thirds of that of the base alloy. The hardening capacity of the FSWed samples was about twice of that of the base alloy. The strain hardening exponent of the base alloy was found to be about 0.1 whereas it became larger than 0.3 for the FSWed samples. After yielding the base alloy showed a high initial and almost constant work hardening rate, corresponding to linear hardening stage II, followed by stage III with a decreasing hardening rate. Stage II linear hardening was observed to be absent in the FSWed samples.

Jan 1, 2007

By Hans D. Gougar

To meet an increasing demand for minerals, mining operations are moving to ever more remote regions. The lack of a local energy supply and infrastructure, coupled with social and regulatory demands for lowered environmental impact of mining operations, presents an opportunity for a seemingly unlikely competitor ? a nuclear power plant. The Modular Pebble Bed Reactor concept, currently in various stages of research and development around the world, offers a high degree of reliability and safety with minimal consequences for the local or global environment. The passive safety features of this design eliminate the need for the extensive active safety systems that add significantly to the cost of current water-cooled reactors. With the MPBR, as with all nuclear plants, there are no appreciable quantities of waste products released to the environment during normal operations. In contrast with conventional reactor designs, the MPBR would also remain radiologically safe even under the most severe abnormal circumstances. The key to the design is the fuel element. Enriched uranium microspheres are coated with various layers of pyrolytic carbons and silicon carbide to form a highly-temperature resistant particle that effectively retains all fission products. These particles are mixed with graphite and formed into 6 cm pebbles. A randomly packed vessel of such pebbles forms the reactor core through which helium is circulated as a coolant. Computer models and tests performed on actual pebble bed reactors confirm that fuel failure temperatures are not reached even during the most severe conceivable loss of coolant accident. The reactor drives a gas turbine cycle with resulting efficiencies as high as 48%, comparable to natural gas-fired units. The low price of uranium fuel and low maintenance requirements translates into competitive operating costs. However, high capital costs prevent the MPBR from competing with natural gas in most markets. In remote applications where no fossil supplies are readily available, the playing field is more level. This paper summarizes the features of two of the more promising candidates for remote applications and discusses the strengths of the MPBR from the perspectives of fuel supply and environmental impact.

May 1, 2002

By J. S. Redpath

Eighty feet of overburden, thirty feet consisting of fine, water-bearing sands, was encountered during the construction of a shaft collar for Chimo Gold Mines Limited at its Louvicourt, Quebec, property. This paper describes the excavation and construction methods used on the project. Open-cut methods, a sheet pile cofferdam, chemical grouting and special blasting methods were used during excavation. Concrete placement was hampered in the lower portion by a heavy water flow, and aided in the upper portion by an unusual method of form bracing. Plant and • pum11ing facilities are also described.

Jan 1, 1966

By Fathi Habashi, Ahmet Deniz Bas

"The mechanism of leaching of semiconducting minerals such as PbS, ZnS, UO2, etc., has been the subject of intensive speculation by hydrometallurgy researchers in the early 1950s who assumed the formation of intermediate surface complexes that could be neither separated nor identified by physicochemical techniques. The electrochemical theory of leaching introduced in the late 1960s resolved this problem by comparing the leaching process to a corrosion phenomenon similar to the corrosion of metals. Few years later, experimental evidence showed that anodic and cathodic zones are formed on the dissolving mineral although no electric current is imposed on the mineral during dissolution. A discussion of these findings is outlined.INTRODUCTIONIn the early 1950s researchers realized that kinetic studies for leaching ores are as important as thermodynamic calculations. It was also during this period that the concept of species adsorption on mineral surfaces has dominated the interpretation of the mechanisms of most reactions. This may have been due to the fact that many researchers of this period came from the mineral dressing sector and were influenced by flotation theories. However, when the knowledge of lattice defects and the semiconductivity of minerals became known and their importance in extractive metallurgy was realized, there was a need to explain the leaching reactions in light of these modern theories (Habashi, 1969, 1970). Semiconducting minerals of importance in metallurgy are two categories: the sulfides such as those of copper, lead, zinc, and the oxides such as those of uranium."

Jan 1, 2016

By P. M. Shibley

"IntroductionMine drainage, surface. drainage and process liquors are the principal mine and mill effluents. The quantity and quality of these flows varies according to mineralogy, type and scale of mining, the process, tailing disposal, local ground conditions and climate.Typical contaminants remaining after solids sedimentation are colloidal or semi-colloidal particles, acids, alkalis, metals in solution, cyanides and thiosalts. Environmental regulations and guidelines have been issued in detail by the appropriate government agencies and will not be reviewed here. Revisions and additions are being made as our comprehension and abilities increase. Some contaminants of consequence have not been specifically regulated as practical treatment technology has not been identified. Thiosalts fall into that category as do the derivatives of the first stage of cyanide oxidation - cyanates.Most mining activities have present or foreseeable water treatment requirements. Because process economics can be adversely skewed by the environmental factor, the acknowledged objective of every operation must be to identify and anticipate those requirements.The evaluation and selection of water treatment techniques for mine-mill applications is complicated by the fact that most mine-mill effluents are high volume, dilute and chemically complex systems. Treatment processes applicable to most contaminants are: chemical or biological oxidation; neutralization and/or precipitation; liquid/solids separation. Other processes such as ion exchange, electro-deposition, foam fractionation, freeze crystallization and reverse osmosis offer the possibility of selective removal or concentration of contaminents. The latter tediniques, representing a slightly higher level of technology, are less suited to the large, low value flows usually encountered in the mine environment."

Jan 1, 1989

By Neillm Alastair S.

"This paper looks at what has happened in the past decade in the rare earth industry, particularly for those companies outside China trying to develop alternative projects to the Chinese dominated supply chain. The rare earth industry has gone through a metamorphosis over the past decade. The industry was basically unknown outside China until overnight it became the next hot topic on the financial streets of Canada and Australia. Suddenly various junior miners shifted from uranium and other out-of-favor commodities to rare earths as funds were easy to access from an investment community that did not understand the complexities of the space. The initial funding was done on traditional junior mining metrics of grade and deposit size. This has morphed over time to:1) Lights versus heavies2) Making a concentrate3) The importance of separation4) Off-take agreementsAt the peak of the market frenzy certain flagship operations were built using the “Not Made in China” moniker. Unfortunately certain errors were made during implementation, which are finally coming to the surface and making the rest of the pack wondering what will happen next. A review and update of some of the mistakes made and lessons learned will be discussed.BACKGROUNDAbout ten years ago awareness started to form around the rare earth industry and various groups recognized that because of the closure of Molycorp, Mountain Pass, and the dominance of China, there was a risk of uncertainty of reliable supply. This was not news for those active in the industry like Rhodia (now Solvay), the Japanese, South Koreans and other key consumers but to others it was like a light went on and rare earths became the new “.com” trend for investment banks, investors and some mining companies looking for the next hot topic.In the late 1990’s Molycorp accounted for around 20-25% of the world’s supply of rare earths, mostly lights (La, Ce, Pr and Nd), with small amounts of heavies from other sources. Then environmental issues forced the closure of the operation at Mountain Pass. Within six months China had increased production to plug the gap in supply. Around that time China was developing a strategy to leverage their position in rare earths and implemented a series of regulations to increase the value added component of rare earths inside China."

Jan 1, 2016

By Jan Drzymala, Przemyslaw B. Kowalczuk

Froth flotation is widely used for upgrading of ores and other materials. Efficiency of flotation depends on many parameters, including type, chemical structure and dose of flotation reagents. Selection of a proper frother in flotation depends on the material used, necessary dose of frother and its selectivity. The selectivity of flotation can be characterized by proper separation factors and indices. In this paper separation selectivity and power of frothers were evaluated basing on separation data for a given material and frother, plotted as the recovery of the useful component in the concentrate versus the recovery of the remaining components in the tailing. Such a plot is called the Fuerstenau upgrading curve. The selectivity was defined as the location of the whole upgrading curve in relation to no and ideal separation lines, expressed on the scale from 50 (no separation) to 100% (ideal separation). In turn, the flotation power was defined as the dose of frother to reach a certain upgrading level at which recoveries of the useful and unwanted components are equal. The power and selectivity of frothers were determined for the Kupferschiefer stratiform copper ore floated in the presence of a fixed amount of xanthate and varying doses of frothers using a laboratory flotation machine. Basing on the separation results for different poly(propylene glycol) (CnH2n+1O(C3H6O)mH, CnPm) and poly(ethylene glycol) (CnH2n+1O(C2H4O)mH, CnEm) alkyl ethers, it was found that the concentrate yield and recovery of copper as the useful component in the concentrate were greatly influenced by the type and dose of frother. However, the same results plotted in the form of the Fuerstenau upgrading curve clearly indicated that the selectivity of frothers was similar, while their power was different. It proves that both selectivity and power of frothers are useful parameters for characterizing flotation systems.

Jan 1, 2016

The University of New South Wales (UNSW) has been a world leader in the development of innovative virtual reality technologies over the last 10 to 15 years. These developments have included developing the world?s first 360° surround, virtual reality (VR), stereo projection theatre system known as AVIE (Advanced Visualisation and Interactive Environment), which was developed by iCinema, a collaborative venture between the UNSW Faculties of Engineering and College of Fine Arts. The UNSW School of Mining Engineering has been responsible for development of mining applications virtual reality software modules and to date, has developed eighteen different mine safety training and mining engineering education modules which run in the AVIE environment. This platform and technology package provides a unique ?immersive environment? experience for groups of trainees or students who can engage with the simulated environment in the complete safety of the virtual reality theatre. In all of the major international mining industries, safety is of paramount importance, and training of personnel is an essential component of any comprehensive proactive safety management system. All personnel need to be aware of the inevitable hazards around them at all times, as well as understand appropriate safety and operational procedures. This can be done by conventional class-room style training sessions, or by provision of training documentation. However the effectiveness of such systems is often very limited due to the inability of trainers to engage with the audience for a lengthy period of time; or to convey the often complex and variable mining environments and situations which can exist in a typical mine. The ability to immerse the trainees in a virtual mine environment, with all the reality of an actual mine but with none of the physical exposure to actual hazards, provides a far more effective and engaging training experience. Furthermore, in the virtual world, trainees can be exposed to the very unlikely, but nevertheless high consequence hazards such as mine fires, falls of ground or outbursts, without any risk to their safety and well-being. The end result is that trainees will be far more engaged with the learning environment they find themselves in, and will develop a far higher level of understanding of the topics, rather than simply experiencing a passive class-room style learning environment offered by conventional training modes. The UNSW systems have been implemented widely within the Australian mining industry and the mining engineering education sector and are now being adopted internationally. This paper presents an overview of the innovative technologies involved in these virtual reality systems ? as applied to the mining industry. Modules developed for both mineworker training and mining engineering student learning will be presented, to illustrate the effectiveness and value of such a training and education approach.

Aug 1, 2013

By F. Rosenblum, P. Spira

"Self-heating of broken sulphide ore or waste rock underground can lead to ignition and cause serious problems in a mine operation. An extensive study has demonstrated that it is caused by oxidation of certain species of pyrrhotite. Self-heating was found to take place in two stages, first progressing from ambient temperature to 1000C with exothermic formation of elemental sulphur in the presence of moisture and oxygen, and proceeding to a second stage in which the sulphur oxidizes to SO2. Ignition may eventually follow. An apparatus was developed to assess the propensity of sulphide rock to self-heating and the potential for hazardous behaviour. The effect of temperature, time, rock size, and surface treatment with chemicals is presented. On the basis of these results, possible approaches for preventing a runaway reaction are suggested for further investigation.IntroductionThe oxidation of sulphide ore, waste rock or tailings backfill, which may cause hazardous conditions underground through heating, oxygen depletion and, in some cases, fire, is well documented (Farnsworth, 1977; Ninteman, 1978; Rosenblum et al., 1982; Reimers, 1987). The self-heating mechanism, nevertheless, has not been satisfactorily explained. The onset of heating from ambient temperature, in particular, has not drawn the attention of researchers. In the course of a previous study (Rosenblum et al., 1982) aimed at finding a method to assess the hazard from using sulphide tailings as backfill, the authors developed an apparatus to measure self-heating rate under controlled, near ambient conditions. This has since provided decisive information in backfill investigations in the Noranda Group.The test methodology devised for tailings failed to predict self-heating in a broken waste rock known to be active. Upon repeated testing, however, a freshly crushed sample began to exhibit appreciable heating and oxygen uptake (Fig. I). After 14 tests, the self-heating rate reached a plateau of about 4O°C/h and then fell progressively to < 5°C/h after 30 tests. It was hypothesized that weathering in the presence of moisture and oxygen during testing had caused the onset of self-heating. Active tailings, on the other hand, are exposed to natural surface oxidation and need not be weathered to show heating. Based on this finding, a new apparatus was developed capable of simultaneously weathering a sample of rock and monitoring its self-heating behaviour."

Jan 1, 1995

By Shinji Shirakawa

The gold wire bonding technology is widely used for electrically connecting aluminum pads on IC devices to external terminal of semiconductor. In 1960?s, the tensile strength of gold bonding wire was about 100 MPa only. However, recently the wire with 300 MPa in strength has been developed. Since the gold bonding wire was started to use for IC package in early 1960?, the many types of gold bonding wire has been developing continuously in order to meet market?s needs, such as high density, small size and thin type of IC packages. Moreover, electronic equipments were used in automobile applications and also demanded good reliability under severe temperature environment. Thus Au-Pd alloy wire has been introduced instead of the wire with 4N(99.99wt%) purity gold to provide excellent reliability in Au-Al bond interface. The phenomena at Au-Al interface in the high temperature storage have been already explained by several studies as follows. There are five phases of inter metallic compound (IMC) between gold and aluminum. Just after bond gold ball on aluminum pad, Au5Al2 phase was formed and occupied almost all of IMC area. During high temperature storage test, Au5Al2 phase transformed to Au4Al phase, then this phase was corroded by Bromide (Br) ion that was isolated from molding resin. Thus the reliability between Au and Al degraded. In case of Au-Pd alloy wire, the concentrated palladium phase (Au-Pd-Al) was formed at the interface between Au alloy ball and Al pad. The Au-Pd-Al phase prevented from transforming between Au and Al, therefore Au5Al2 phase was hard to transform to Au4Al phase. Consequently the reliability at the interface between Au alloy ball and Al pad was less degradation. However, in recent study using several advanced analysis technique, Au4Al phase was found at the interface between Au alloy ball and Al pad same as the case of conventional gold wire (4N purity gold bonding wire). It was suggested that the formation of concentrated palladium phase (Au-Pd-Al) related the excellent reliability at ball bonding process.

Oct 1, 2003

By David J. McDougall

"The production of pig iron, wrought iron bars and castings in Quebec during the 18th and 19th centuries has been so closely identified by historians with Les Forges du St. Maurice on the St. Maurice River a few miles north of Trois Rivieres (Three Rivers), that one is sometimes left with the impression that it was the only iron works that ever operated in the province. There were however, about twelve others, one of which was so completely re-built that it should probably be considered as a separate entity. All but two were constructed after the midpoint of the 1800s, coinciding with the growing Canadian demand for ""charcoal pig"" for railway car wheels and castings for industry, and about half of them were technically, if not economically, successful. The misconception about Les Forges du St. Maurice may have come about either because of its long history of somewhat less than continuous production over a century and a half, or a tendency of Quebec historians to concentrate on events in the French-Canadian milieu, but whatever the reason, the other Quebec iron works have been generally ignored. All but one of the Quebec blast furnaces could be described as ""pre-industrial"" with capacities ranging between three and ten tons per day, the exception being the Radnor furnace built in 1892 with a maximum production of about 35 tons per day and an alleged capacity of 50 tons per day. Until a railway network was completed in the 1880s, the location of all the Quebec iron works except the Grantham Iron works was dictated by close proximity to adequate ore reserves because horse transport was of little use beyond a ten-mile radius. The other essentials of forest resources (mainly soft woods) for charcoal, limestone for flux and water power, were generally available except within a few miles on either side of the St. Lawrence River. Among the dozen iron works established in Quebec between 1732 and 1880, seven used bog iron ore in charcoal-fired furnaces. Five of these, including Les Forges du St. Maurice, were located on or near the St. Maurice River which enters the St. Lawrence River from the north, and two, the St. Francis Forges and the Grantham Iron works were on or near the St. Francis River which enters the St. Lawrence from the south. In a general way deposits of bog iron ore in the St. Lawrence lowlands of Quebec were contained within the limits of the post-glacial Champlain Sea, with many clustered along the flanks of the St. Narcisse recessional moraine which is crossed by the St. Maurice and other near-by streams, and the Drummondville recessional moraine which is crossed by the St. Francis River."

Jan 1, 1999

By Ian S. Leslie

Seismic monitoring systems for mining operations are being utilized more than ever before in the characterization of rock mass response to underground and open pit mining. This paper provides a review of the use of microseismic monitoring for rock mechanics applications at mines throughout the world. Some practical considerations for the installation of these systems are presented along with techniques for optimizing seismic array coverage. Case studies and installation examples are also provided. Recent applications of advanced seismic analysis techniques are discussed including the determination of event mechanisms, mapping of maximum peak particle velocity (PPV) and seismic hazard fields, and the use of source parameter data for large event re-entry protocol.

Jun 1, 2012

By L. Dufourm

This paper presents a review of plant layout considerations incorporated into recent designs of SAG/Ball mill circuits for two medium sized concentrators. The plant layouts presented and the design concepts discussed, relate to smaller SAG circuits, but can equally apply to larger milling circuits. Included are design concepts and ideas introduced by the various project teams, and the focus is on the primary factors of any layout design which are safety, constructability, operability, and capital cost.

Jan 1, 2012

By T. R. Madhavan

The development of contact angles on highly polished ?uraninite surfaces, using sodium oleate and dodecyl ammonium acetate as collectors, has been studied at different collector and hydrogen ion concentrations. It was found that sodium oleate in acidic media (up to a neutral: PH) and dodecyl ammonium acetate in neutral and alkaline media give good contact angles. It appears that the combined forms of these collectors, viz., oleic acid and free amine, are more important in effecting contact. W ITH the emergence of uranium as a strategic metal in the last fifteen years, considerable effort has been directed toward the commercial recovery of uranium from its ores. This has resulted in the development of a uranium technology. It is only in recent years, However, that fundamental data regarding the floatability and surface properties of uraninite and ?pitchblende have been elucidated by different methods. Contact-angle measurement is one of the important tools for tl1e evaluation of the conditions of floatability

Jan 1, 1964