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By Donald E. Archibald, Gerald A. Allcott

"Noranda's Heath Steele Mine is located 35 miles north of Newcastle in northern New Brunswick. Blasthole open stoping with partial delayed filling is the major mining method in use. The selection of stope and pillar dimensions to ensure mine stability was originally subjective. This paper describes the progress made in attempting to rationalize design.One major feature is the fracture pattern. The main orebody now being mined, the B zone, has undergone five periods of folding and each period of folding developed a family of fracture planes which are axial planar to that particular fold pattern.The other major features considered are the calculated increase in stress due to mining and depth and its relationship to measured strain. Experience has shown that ground problems affecting production have usually originated in rib pillars. Field observations of ground deterioration and multi-wire extensometer measurements of strain are tabulated together chronologically for each pillar.A factor representing stress and a common plane of weakness are identified. Graphical analysis is used to determine the effect of the plane of weakness on a typical stress/strain curve and provides a base for the design of pillars."

Jan 1, 1981

By D. O. DeGagné, J. F. Archibald

Spray-on polymer linings, as partial or full replacement for traditional forms of area rock support, have seen rapid growth in interest within Canada. A wide variety of lining types, ranging from polymer chemical to water-based cementitious materials, have been developed and commercially introduced to the underground mining market. Following approximately one decade of development work, several general conclusions have been reached regarding the performance of this class of area support media, these being that: health and safety assessment of the broad range of materials has shown the majority of them to be acceptable and safe for underground use; significant ground support potential can be offered by them, being equivalent to or better than capabilities offered by traditional support forms such as bolt-and-screen or shotcrete, and; their abilities to be rapidly deployed and provide near instantaneous support restraint offer considerable operational and cost benefits to underground operators. A review of currently available liner materials, their historic development within the Canadian mining industry, and overviews of support, health and safety, operational considerations and cost benefits are provided in this paper.

Jan 1, 2001

By J. L. Feng, F. Zhang, S. K. Hu

"Cracking is one of the most serious damages in tunnel linings, which is often observed by in-situ inspection to tunnel engineering. It is difficult to better characterise for the deformations from continua to discontinua by the traditional continuum mechanics due to emerging of crack initiation, crack propagation, and coalescence, at several scales. In this paper, the process of failure that was from micro damage to macro crack in concrete tunnel linings under experimental load conditions, was quantitatively simulated by the combined finite-discrete element method (FDEM). Comparison of the simulating results with that obtained by the full-scale test of concrete lining under different loading conditions in the literature was respectively good agreed and shows that such FDEM technique is appropriate to model the continuousdiscontinuous problems. The present study indicates that the FDEM technique could be benefit to quantitatively evaluate the stability and damage level of tunnel lining system. INTRODUCTIONMost damage to tunnel linings is caused during the construction phase, which can emerge in a form of single macro cracks or even large-scale spalling. The cause of such damage is mostly the occurrence of, either impermissibly large contact stresses resulting from high thrust loads combined with production and installation tolerances in the segments resulting in a geometrical lack of fit (Maidl et al., 2012; Transportation Research Board, Basic Research and Emerging Technologies Related to Concrete Committee, 2006), or unallowable tensile/shear stresses appearing in the tunnel linings under complicated loading conditions (Ansell, 2010). Such a macro failure phenomenon may also be regarded to as a result of growth, coalescence, initiation of microcracks in tunnel linings due to the complicated loading action, and even potentially lead to an instability or collapse of the local or entire tunnel system. Much work has been devoted to investigate for the characters of micro and macro cracks, the influence factors of damage patterns, the settlement of a tunnel, the width, length and density of lining cracks, especially from classifiedly and qualitatively (Wang, 2010; Huang et al., 2013). However, the safety evaluation of tunnel is definitely required to not only inspect in situ, but further also quantify computing and analyzing for tunnel lining systems, so as to provide a global viewpoint of process of the tunnel deformation, which aims to help for subsequent decisions, e.g. controlling traffic flow or immediately repairing task. Additionally, the design of lining thickness and its structural analysis that is mostly determined by previous experience and similar construction examples is also needed to be improved."

Jan 1, 2015

By J. R. Morris

"A hoisting plant design should satisfy two basic requirements:1. to provide the necessary materials handling capacity, including ventilation where applicable, while meeting the requirements of good practice and, as a minimum, government regulation; and2. to optimize the economics of the project. Selection of hoisting equipment to meet the first objective is a complex but logical engineering process. The necessary calculations of payloads, accelerations, speeds, rope strength, hoist size, and power requirements are very readily carried out on computers or programmable calculators. A variety of hoist options can be quickly examined to assess the effects of changes in design parameters.Meeting the second requirement involves balancing the costs of various hoist arrangements and shaft designs, together with the time cost effects of differing shaft sinking rates and potential advances to be gained by concurrent level development. The proposed mine layout is significant here, as is the possibility of future shaft deepening and/or production increase. The availability of used equipment may be significant, both as regards first cost and delivery time. The factors are interactive, with their relative effects .varying from project to project. This paper sets out the primary factors to be considered."

Jan 1, 1990

By R. C. Fernandes, F. L. Santos

Aluminum alloys in particular, have certain limitations when subjected to welding process. This is mainly present because aluminum alloys have high thermal conductivity, high contraction in solidification and high hydrogen solubility. Taking this into account, the FSW process has great potential for this application, since it is autogenous, held without metal melting and without the use of slags or shielding gases. From this concept, the aim of this study is to evaluate the joining of thin sheets of aluminum alloy 3105 H26 with 0.7 mm of thickness. To performing of the tests, some parameters were analyzed, such as: tool penetration in the sheets, attack angle, the type of welding tool and penetration control mode (position or force). The results indicated that the force control mode is most suitable for thin sheets, and the transient state at the beginning of welding was the most critical part to control the welding quality.

Jan 1, 2015

By B. J. Walsh

ABSTRACT Segregation of sphalerite minerals in zinc concentrates into christophite, marmatite and ordinary sphalerite by means of magnetic fractionation is investigated. A Frantz ferromagnetic filter, 1.2 amp., and a Dings magnet, 0.3 amp., is used to fractionate seven zinc concentrates produced in the Province of Quebec. The Dings magnetic product contains the pyrrhotite, and the sphalerite as christophite. The Frantz magnetic product contains sphalerite as marmatite, while the Frantz nonmagnetic product contains ordinary sphalerite. The results indicate that the magnetic susceptibility of sphalerite increases with increasing isomorphous iron content and that a satisfactory separation into christophite, marmaite, and ordinary sphalerite may be accomplished by magnetic fractionation. INTRODUCTION SPHALERITE, the chief ore of zinc, is almost never pure zinc sulphide. Iron is almost always present isomorphously replacing an ?equivalent amount of zinc. What may be referred to as 'ordinary' sphalerite contains up to 10 per cent iron. More highly ferriferous varieties, with 10 to 26 per cent or more iron, have been named marmatite .and christophite.

Jan 1, 1951

By P. Z. Caverhill

In this section of the province only the most meagre of surveys have been made and because these are not sufficient to determine with any degree of accuracy even the total forest area, the information presented in this paper is not complete. Area: -The area south of the Canadian National, and served by the Pacific Great Eastern, is roughly 38,000. square miles, 30,000 of which is classed as productive. This is approximately equal to the productive area of Norway, or half of Finland-or of 30 per cent of Sweden. It is larger than that of either Nova Scotia or New Brunswick. Eliminating from the productive area 3600 square miles of grass-land and areas capable of agricultural development, 26,000 square miles (16,600,000 acres) remains as absolute forest-land, as compared with the 55,000,000 acres of Sweden, the 37,500,000 acres of Finland, the 17,000,000 acres of Norway, and the 7,600,000 acres of Austria.

Jan 1, 1925

By S. E. Jackson, L. J. Cabri

Quantitative determination of gold at sub-ppm concentrations in sulphide minerals is an important component of deportment studies for sulphide-gold deposits. Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) analysis is preferred for this application because it rapidly and cost-effectively provides spatially resolved (<20 pm), low ppb concentration data for gold and other elements in mineral grains. Recent advances in LA-ICP-MS analysis include the development and application of elemental mapping. Raw signals from multiple line scans or lines-of-spots are deconvoluted and calibrated to generate elemental maps which provide detailed information on spatial variations of gold and other elements within and between grains.

Jan 1, 2011

By Charles J. Zablocki, Robert J. Kamilli

"Abstract - Buried, possibly mineralized granite cupolas at the Silsilah tin deposit in Saudi Arabia (lat. 26°06&apos; N, long. 42°40&apos; E) have been successfully located using a closely spaced electric-field-ratio profiling technique. In this study, electrical fields at 27 and 270 Hz across grounded electrodes spaced 50 m apart were measured along six traverses. This method is interpretable by inspection, unlike the dipole-dipole technique, which requires mathematical modeling for interpretation.In the study area, the technique allowed the authors to identify and distinguish among unroofed granite cupolas, cupolas with their aplite-pegmatite apical contact zones intact, strong (quartz-rich) and weak (relatively quartz-poor) greisens, dikes, faults, and pervasively argillized rocks.This method should be useful in the valuation of other shallow mineral prospects in similar settings in other parts of the world, especially deposits for which the location of vertical contrasts is important, such as veins or mineralized zones associated with the apexes of small igneous cupolas."

Jan 1, 1993

By J. W. Meier, J. O. Edwards, R. C. Bell

"IntroductionTHE DIE CASTING industry .as we know it today is the direct result of the invention and development of die casting machines during the nineteenth century and of reliable alloys in the twentieth. The early machines were designed to cast low melting point metals such as lead .and tin, and their alloys.It was inevitable that, as these die castings were put into service, the demand should arise for stronger materials. Zinc alloys, often containing lead, tin, copper, and aluminum as major constituents, were relatively easy to cast and stronger than the lead and tin alloys. However, it became apparent after a number of years that these zinc alloys tended to become brittle, distort, and corrode, particularly if kept in warm, humid atmospheres. Thus, considerable quantities of zinc-base .alloys were in use before the trouble was realized and effective measures could .be taken to determine the cause of the instability.The deleterious effect of certain metallic impurities on the properties of zinc •die casting .alloys has now been known for about thirty years. Brauer .and Peirce, and, later, other research workers of the New Jersey Zinc Company such as Anderson and Werley, discovered the pronouned effect of lead, cadmium, and tin on the stability of zinc-alloys."

Jan 1, 1952

By L. Frost

"Since the late 1990s, increased prevalence of severe lung disease among US coal miners has been observed, particularly in central Appalachia where thin-seam mining is prevalent. While respirable silica exposures have been implicated in many cases, the available dust monitoring data from mines shows no explanatory trends. One possible factor could be differences in the relative toxicity of silica particles based on their surface condition. Previous research has indicated that particles with occluded surfaces (e.g., by a thin layer of clay) may be less toxic than those with non-occluded surfaces. However, this dust characteristic has not been investigated before now in central Appalachian mines. In the present study, 18 respirable dust samples from seven central Appalachian mines and two northern Appalachian mines were analyzed to assess the relative occurrence of surface-occluded silica. Results showed that the dust from central Appalachian mines actually had higher fractions of occluded silica, which may be due to extraction of large amounts of rock strata along with the coal. However, the central Appalachian mines also more silica particles overall (i.e., occluded + non-occluded) in terms of total number percentage of respirable particles.INTRODUCTIONResurgence of occupational lung disease among US coal miners, especially in the central Appalachian region, has been observed since the late 1990’s (Gibson, 2016; Zosky et al., 2016; Suarthana et al., 2011; Gamble et al., 2011; Antao et al., 2005; Attfield & Sexias, 1995). In addition to increased prevalence of simple Coal Workers’ Pneumoconiosis (CWP, or “black lung”), the prevalence of severe and rapidly progressive disease has risen dramatically (Almberg et al., 2018; Blackley et al., 2018a, 2018b, 2016, 2014; Graber et al., 2017; Cohen et al., 2016). While exposures to respirable silica have long been known to cause or play a role in diseases such as silicosis or progressive massive fibrosis (PMF), which is conventionally considered as the most advanced form of CWP, it is unclear whether silica is the only culprit in the recent outbreak of severe disease. Indeed, as disease rates have risen, both total respirable dust and silica concentrations generally appear to have declined since the late 1980s, based on regulatory monitoring data in the most affected mining districts (i.e., MSHA coal Districts 4, 5 and 12, which cover central WV, eastern KY and southwestern VA, and southern WV, respectively) (Figure 1). Of course, the latency of disease can vary and may be or more 10 years, but many of the most recent cases are likely to have resulted from exposures that occurred since the late 1980s."

Jan 1, 2019

By Linlin Tong, Xiangling Song, Guobao Chen, Zhenan Jin, Hongying Yang

Biooxidation of a high arsenic-bearing refractory gold ore was investigated to determine the arsenic removal efficiency by the cultured bacteria and to examine the effect of biological pretreatment on subsequent gold cyanidation. The biooxidation pretreatment process utilizes the ability of adapted acidophilic bacteria to oxidize pyrite and arsenopyrite and release the encapsulated gold. The released gold can be efficiently extracted by the subsequent cyanidation process. The biooxidation experiments were conducted with cultured bacteria using various sizes of agitation tanks. Leaching results showed that over 96.26 % arsenic extraction could be obtained from this ore after 6 days of bioleaching with continuous stirred tank reactor (CSTR). Gold extraction during the cyanidation process was increased from 29.35% to 96.71% after biological pretreatment. The content of arsenic in the biooxidation residue was reduced to below 0.3%. The transformation process of As was considered as [AsS]2- ? As (?) ? As (?) during the biological pretreatment.

Jan 1, 2014

By Jason Berenyi

Presentation Overview ? What is Potash? ? Where are the potash deposits? ? Current potash mines ? production, capacity and planned upgrades ? Saskatchewan Saskatchewan?s Potash Production Potential s ? Current Status of Potash Exploration ? Increasing Demand for Potash ? Saskatchewan global role

May 1, 2009

By C. A. Pickles

Microwaves are being applied industrially in a number of fields and possess a number of potential advantages that could be applied in extractive metallurgy. Microwave heating has a number of unique characteristics, which distinguish it from the conventional heating methods. In microwave heating, the absorption of energy occurs at the molecular or atomic level and therefore the heat is generated within the material itself. In conventional heating, the exterior temperature is usually higher than the interior, but with microwave heating, the temperature gradient is inverted and thus the interior temperature can be much higher than that of the surface. The energy densities in microwave systems can be relatively high and this in combination with the low thermal conductivities of oxide ores, can lead to very high internal heating rates. In this research, the application of microwave energy for the reduction of a nickeliferous silicate laterite ore has been investigated. The real and imaginary permittivities are the two fundamental properties which determine the microwave absorption characteristics of a material and these were measured for the ore, both with and without carbon additions using the cavity perturbation technique. The microwave heating and reduction experiments were performed in a 0 to 2 kW CTC microwave system. The effects of power input, processing time, sample mass and charcoal additions on the microwave absorption were investigated. Then reduction experiments were performed and the nickel grade of the magnetic concentrate and the nickel recovery in the concentrate were determined.

Jan 1, 2005

By James W. Cameron

DESPITE the fact that, after oxygen and silicon, aluminum is the most abundant and widely distributed element in the earth&apos;s crust, it is, commercially, a modern metal. Attempts were made by Sir Humphrey Davy and other chemists to decompose alumina, the oxide, into its elements, but with unsatisfactory results, and it was not until 1827 that Wohler succeeded for the first time in isolating the metal in pure form. Some thirty years later, commercial production of aluminum was started in a plant near Alais, France, using a process developed by Deville which was a modification of that of Wohler. It was not, however, until around 1886 that possibilities of low-cost production were realized. Hall and Heroult discovered, independently, the now famous process for extraction of aluminum by the electrolysis of alumina (Al,O,) dissolved in fused cryolite. This discovery, with its subsequent effect in reducing the price of the metal, was perhaps the greatest single factor contributing to the remarkable growth of the aluminum industry. But only in the years following the Great War did aluminum begin to attain equal importance in many fields with other non-ferrous metals. Numerous factors, political and economic, in the past decade have had a profound effect on the industrial history of the metal. At present, systematic substitution of aluminum for other base-metals is proceeding at a rapid rate in such countries as Germany and Italy with a view towards &apos;economic self-sufficiency&apos;. Quite naturally, ?the economic depression started extensive research and experiment in various industries in an attempt to improve efficiencies and lower costs. Partial answers have been found in the extended use of aluminum and its alloys. Even against the background of tremendous technological advance that has marked the past fifty years, the rise of the aluminum industry must necessarily stand out conspicuously.

Jan 1, 1939

By M. Pelegrin Rodríguez, J. Castellanos Suarez, R. Causse Miyares, A. Mosqueda Martínez, Rubén Aja

"This paper will describe the methods and the results of studies to integrate polymetallic nodule extractive metallurgy methods into existing and operating technologies or plants with the aim of reducing the capital cost of deep-sea mining challenges and to streamline the supply chain of raw materials where such opportunities exist (Moa Bay and others). It will also assess the possibility to carry out pre-industrial processing operations with productivity corresponding to pilot mining operation in the Clarion Clipperton Fracture Zone (5–10% of assumed annual production) with the use of existing facilities. The present study shows the results of high pressure acid leaching of polymetallic nodules (PN) mixed with laterite non-commercial ore. It also presents PN processing in the presence of ammoniacal tailings obtained from the Caron process. The experiments were carried out according to 24 full factorial design. The regression equations were determined for extractions of Ni, Co, Cu, Zn, Fe and Mn. The obtained results show that increasing temperature, the acid/ mineral ratio and the leaching time have a positive and significant effect on extraction of all the studied metals. However, increasing the tailings addition favors the extraction of the Co, Zn and Mn. The extraction of Fe diminishes, while the extraction of Ni is not affected. In the following conditions; 180 min, 260°C, 0.5 kg acid /kg minerals and 2.5 kg PN/kg tailing; the following extractions were achieved; 96% Ni, 90% Co, 97% Cu, 99.9% Zn, 43% Mn and 26% Fe."

Jan 1, 2017

By N. Erarslan, M. Ghamgosar

With the increased use of mechanized rock excavation, there have been developed internationally a number of methods to assess the abrasivity of rock materials. These methods range from determination of abrasive and hard mineral content using petrographic thin section analysis to weight loss or rate of wear flat development on specified test pieces. The Cerchar abrasivity index (CAI) test has been widely accepted for the assessment of rock abrasiveness and is determined as the abrasion of a steel pin after scratching over the freshly-broken or saw-cut surface of a rock. Two types of testing devices are in use today: (i) the original ‘Cerchar apparatus’, and (ii) the ‘West apparatus’, which was adopted herein. The CAI is calculated from the measured diameter of the resulting wear flat on the steel pin after 10mm scratching. This test has been considered to provide a reliable indication of rock abrasiveness for isotropic rocks. However, a great amount of rocks in natureis anisotropic. Phyllite is an anisotropic and foliated metamorphic rock and various types of phyllite specimens were tested in this research. Although phyllite is a type of rock primarily composed of quartz and the expected CAI value can be high, mechanical cutting of this rock should not be very problematic compared with igneous rocks have same CAI value. As phyllite is a foliated metamorphic rock, most of the specimens split into sheets through the quartz seam by the tip during scratching normal to the axis of quartz seams. Hence, viability assessment of Cerchar abrasivity test and F-Schimazek index values for the anisotropic rocks is investigated in this research.

Jan 1, 2015

By S. Noh, T. K. Kim, B. O. Lee

Future nuclear reactor systems such as a sodium-cooled fast reactor are being designed under severe conditions in terms of operating temperature and irradiation fluence compared to current commercial reactors. For realization of such systems, it is necessary to develop an advanced structural material having both high strength and irradiation resistance at high temperatures. Oxide dispersion strengthened (ODS) steel is considered as one of the most promising structural material because of its excellent creep and irradiation resistance on the basis of uniformly distributed nano-oxide particles with a high density. Up to now, ODS steels have been intensively studied and developed to apply these materials to the in-core structural component of future nuclear systems. Several advanced ODS steels were designed and fabricated by a mechanical alloying, hot isostatic pressing and hot extrusion processes. This study focuses on the effects of heat treatment parameters during the fabrication process parameters on the microstructures of ODS steels for future nuclear system applications.

Jan 1, 2015

By Charles J. Zablocki, Robert J. Kamilli

"Buried, possibly mineralized granite cupolas at the Silsilah tin deposit in Saudi Arabia (lat. 26°06&apos; N, long. 42°40&apos; E) have been successfully located using a closely spaced electric-field-ratio profiling technique. In this study, electrical fields at 27 and 270 Hz across grounded electrodes spaced 50 m apart were measured along six traverses. This method is interpretable by inspection, unlike the dipole-dipole technique, which requires mathematical modeling for interpretation.In the study area, the technique allowed the authors to identify and distinguish among unroofed granite cupolas, cupolas with their aplite-pegmatite apical contact zones intact, strong (quartz-rich) and weak (relatively quartz-poor) greisens, dikes, faults, and pervasively argillized rocks.This method should be useful in the valuation of other shallow mineral prospects in similar settings in other parts of the world, especially deposits for which the location of vertical contrasts is important, such as veins or mineralized zones associated with the apexes of small igneous cupolas."

Jan 1, 1993

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