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By Scott L. Ewart, William M. Bryden, Donald E. Wakefield

"Osler, Hoskin & Harcourt develops commentaries from time to time on topics of legal interest. These may deal with new legislation, changes or developments in government policy or recent judicial decisions of importance to its clients. The commentaries are, of necessity, general in nature. Because the law which they deal with is often new and untested, it is hard to arrive at precise statements of the way in which the principle s discussed in a commentary might be applied in specific circumstances. When further guidance is needed , consult a solicitor.The purpose of the Bill is to simplify, modernize and standardize the regulation of mineral exploration and development in Ontario. Many of the changes proposed by the Bill are of an administrative nature and move much of the detail with respect to staking, assessment work, prospecting work, surveys, quarry permits and leases contained in the existing Mining Act to the Regulations contemplated under the Bill.The Bill will undergo revision and be re-introduced and therefore it is not the intention of this present article to detail the specific changes contemplated by the Bill; however , its more significant changes are as follows:1. Provision is made for a lifetime prospector's licence with the elimination of annual renewals;2. Perimeter staking of a block o f claims is permitted to reduce the cost of staking;3. Assessment work requirements are expressed in term s of dollars spent rather than days worked;4. Persons doing exploratory work are required to furnish notice to owners of surface rights of intention to perform assessment work;5. Annual work summaries will be available to the industry to lessen duplication in exploration work;6. The option of continuing assessment work rather than applying for a lease is provided;"

Jan 1, 1984

By A. Rahimi

The smelting plant at Sarcheshmeh Copper complex commenced working with two reverbatory furnaces, four pierce smith converters, two anode furnace and one holding furnace having a known capacity of 420 metric tons of anodic copper according to the initial design in 1982 (1361 Iranian calendar). During the period from the commencement date up until now, the smelting plant has undergone changes for improvement and enhanced production by substituting holding furnace with another anode furnace, installing the fifth converter and utilizing oxyfuel burners on the ceiling of the reverberatory furnaces. According to the different operational processes in reverberatory, converter and anode furnaces different types of corrosion mechanisms and degradation can be observed in the refractories of copper smelting furnaces. In the case of reverberatory furnaces, the corrosion and degradation of refractories may be factors such as hot corrosion by melt, corrosion attack by the constituents of burning fuel, degradation of sidewalk exposed to mechanical stresses of the feed charge and the hydrostatic pressure exerted by the melt inside the furnace, all of which are due to the unique operational condition governing the reverberatory furnaces environment, i.e. burning fuel atmosphere, charge concentration and combination, furnace temperature, calm melt condition, etc. In the case of converter furnaces, the most likely corrosion and degradation of refractories may be due to the chemical reaction between the melt and degradation of tuyere zones due to sever movement of the melt and mechanical strikes of the punch rod. Also the most essential corrosion reaction occurs around the mouth of the converter because of the mechanical strikes by the cleaning device and thermal heat shock. Other parts inside the furnace are corroded due to the reactions between the fayalite slag and the furnace refractory. In anode furnaces the degradation mechanism is mostly related to the gaseous corrosion (penetration of natural gas or liquid gas inside the refractory structure due to the long period of reduction processes and refining stages. Finally another important factor responsible for destruction of refractories in these furnaces is the copper oxide slag together with the fume constituents of burning fuels.

Jan 1, 2004

By Par G. Jönsson, Joachim von Scheele, D. S. Sarma, Mukul Goyal

Dust from flue gas cleaning systems at iron and steel production is frequently considered as a waste problem, but it is actually a potential raw material source. By using a technology like the oxyfuel based OXYFINES technique, it can be melted into a suitable form. The product from this processing, however, needs to meet the requirements of a recyclable raw material, here particularly a top-charged blast furnace feed. The present work has been focused on characterization of the product produced from these dusts by OXYFINES technology. The investigation has been carried out on samples of processed dusts from a European integrated steel mill. It was done by means of chemical analysis, density measurement, light optical microscopy, X-ray diffraction, scanning electron microscopy combined with energy dispersive spectroscopy, and micro indention hardness measurement. Special attention was paid to the presence of zinc, an element that might be harmful while recycling the material (e.g., in a blast furnace). The results show that the product contains four different regions with different morphologies and properties in the material, which are discussed in detail. The overall conclusion is that by processing the dusts in this way, a raw material suitable for recycling in a blast furnace can be obtained.

Jan 1, 2004

By K. Purazrang, P. Musavi Garavi, P. Sh. Naseri, P. Abachi

The fracture behavior of high strength Al7050 alloy was investigated at room and elevated temperatures using small size, V-notched tear (called Kahn specimen) and compact tension, CT, specimens, respectively.To study the elastic-plastic behavior of the alloy, the tensile test was also performed on the sub-sized cylindrical tension test specimen. The microstructure of the alloy was examined using optical- and scanning electron- microscopy. The rupture mechanisms and crack path were also studied by examination of specimens' fracture surfaces using SEM. The microstructure examination revealed equiaxed grains and some elongated grains in rolling direction, with the areas of partial re-crystallized grains where coarse intermetallic particles are mostly found.In general, fracture surfaces were indicative of dimpled ductile type. Considering the fractographs of tensile specimens, the void growth mechanism is also dominant in fracture of these specimens. Nevertheless, in some regions, smooth areas can be observed due to the friction during rupture process. The results of mechanical tests at RT made the evaluation of tear strength to 0.2 % tensile yield strength ratio, as a measure of notch toughness, available. According to elevated temperature, 150°C, test results and plots of log da/dt vs. log KI , the crack propagation behavior over discrete ranges of crack growth rates could be assumed linear and then be obeyed as a power law equation in the form of da/dt = A (KI)n .

Jan 1, 2015

By Paul Ransom

Sullivan Production and Present Value ? Mined 150 million tonnes ? 6.0% Pb, 5.5% Zn, 2 opt Ag, + Sn, Cd, In ? May 2006 Value + US$43 Billion ? 50% of metal from first 37% (55MT) of tons ? True original size ~ 110-120 Mt @ 17%Pb+Zn ? 30MT unconsolidated fill + HW cave

May 1, 2006

By Richard K. Komarek, Antonios Zavaliangos, Roman T. Dec

Current industrial compacting and briquetting practices are largely based on trial-and¬error techniques. This paper introduces a two dimensional finite element model of compacting/briquetting process in the roller press. Compared with other modeling techniques used in the past, finite element method offers the most versatile approach because it incorporates adequate information about powder behavior, geometry and frictional conditions and offers predictions for the density distribution, velocity field, stress distribution, roll force, roll torque and other important process variables. More over, when the model includes elasticity, it offers predictions on the internal stress state in the briquet after its exit from the pressing zone. This enables to perform realistic computer experiments which are helpful for establishing the pressing system design, forming cavity geometry and process conditions necessary to produce compacted or briquetted product with the desired properties.

Jan 1, 2004

By Peter A. Oshust

The EKATI Diamond Mine has successfully completed the development and commissioning of the Panda Underground Project to extract the ore below the Panda open pit. The dominant kimberlite domain of the Panda Underground, intermixed olivine-rich and mud-rich resedimented volcaniclastic kimberlite (RVK), is very similar to the kimberlite domain characterizing the open pit portion of the pipe. A sublevel retreat mining method is in operation underground at Panda; near-vertical blast rings are drilled and blasted into an open void. Broken ore is mucked with load, haul and dump trucks (LHD?s), sized underground then moved to surface through a conveyor system to the process plant. An advanced feasibility study is in progress at the Koala Underground Project. The Koala pipe is geologically more complex than Panda. The pipe below the open pit is comprised of at least five distinct kimberlite domains. There is a 100 m thick zone of incompetent low-grade mud-rich RVK between the open pit and the stable high-grade olivine-rich primary volcaniclastic kimberlite where mining will be initiated. As a result, it is proposed that Koala will employ sublevel caving; each blast ring shot would be confined and mucked in sequence to maintain the cave of the over-lying low-grade RVK ore. The sublevel cave method seeks to safely defer the mucking of the low grade ore to the latter part of the mine life.

May 1, 2006

By K. Murase

Potentiostatic electrodeposition behavior of dendritic copper from acidic copper(I) chloride (cuprous chloride) baths containing sodium chloride and sodium bromide was investigated. The morphology, or appearance, of copper dendrite and the sodium content in the dendrite as an impurity were both influenced by deposition potential (0 to ?150 mV vs. SHE) and bath temperature (R.T. to 60 C), while the current efficiency for the deposition was 99% or more irrespective of the deposition conditions examined. The bath pH did not affect the deposition behavior in the pH range of 0 to 2. Bath temperature was found to be the most important factor influencing the deposition current. The current density of the dendrite deposition on a titanium cathode was lower than that onto a copper cathode with the same substrate surface area. The reproducibility of the current for the dendrite deposition was poorer when an as-polished titanium cathode was used, although it was improved by surface treatment of the cathode with an HF-HNO3-H3PO4 solution before electrodeposition. The deposition behaviors were discussed with the potential-pH diagram of the Cu-Cl-H2O system.

Jan 1, 2007

By James Ransford Dankwah

High sulphur carbonaceous materials like petroleum coke and rubber tyre are unsuitable as reductants in ironmaking because part of the sulphur is transferred to the reduced metal. Globally, while large amounts of petroleum coke are produced annually from the industrial processing of crude oil, billions of end-of-life rubber tyres are held in landfills and stockpiles. This work therefore investigates the potential feasibility of utilising these high sulphur carbonaceous materials as reductants in ironmaking without transferring the sulphur into the reduced metal. Composite pellets of iron oxide containing end-of-life rubber tyre (RT), petroleum coke and blends of RT/petroleum coke and petroleum coke/high density polyethylene (HDPE) were heated under argon atmosphere in a horizontal tube furnace. Reduced pellets were analysed after 10 minutes of reduction for their sulphur content. The results showed that sulphur-free metallic iron can be successfully synthesized using RT and petroleum coke as reductants. The level of desulphurisation depends on the nature of blending of the carbonaceous materials.

Jan 1, 2014

By M. D. Johnson, R. K. Bezys

"The majority of Ontario's limestone and dolostone production comes from a few Paleozoic carbonate units. In eastern and central Ontario, Ordovician rock units, which are the main sources for production, include the Oxford, Gull River, Bobcaygeon, Verulam, and Lindsay Formations. They are predominantly utilized for aggregate and cement manufacturing, with the Bobcaygeon Formation being used as a source of building stone. Along the Niagara Escarpment, the Silurian Lockport, Amabel, and Guelph Formations are sources for the limestone industry. The largest tonnage of rock extracted by the industry comes from these Silurian units, especially the Lockport and Amabel Formations. These units are used primarily for aggregate, although they are also a source for lime. In southwestern Ontario, the Silurian Bertie Formation and Devonian strata, represented by the Bois Blanc Formation, Onondaga Formation, Detroit River Group, and Dundee Formation, contribute to Ontario's production of lime, cement production and crushed stone. The Detroit River Group (Lucas and Amherstburg Formations) is the main source of the lime and cement produced in the province.Northern areas, which may become significant sources for the industry, include Manitoulin Island, the Lake Timiskaming area, and the James Bay Lowland. IntroductionThe Engineering and Terrain Geology Section of the Ontario Geological Survey has undertaken a geological inventory of all active and abandoned limestone and dolostone quarries in Ontario. This geological study, combined with a commercial study of active quarries carried out by the consulting firm of Derry, Michener, Booth and Wahl, will provide an up-to-date report on the industry in the province and will be published by the Aggregate Resources Section of the Ministry of Natural Resources. This report will follow the format and style of D.F. Hewitt's Ontario Department of Mines Industrial Mineral Reports and Circulars (Hewitt, 1960, I964a, 1964b, 1964c; Hewitt and Vos, 1972). Examinations of the quarries were carried out by geologists in the Paleozoic I Mesozoic Geology Subsection of the Engineering and Terrain Geology Section, and include, in addition to the authors, R,R. Wolf, V.A . Mazur, and D.K. Armstrong in the summer of 1986."

Jan 1, 1988

By Martha Gellner, Lutz Wuschke, Hans-Georg Jackel, Urs A. Peuker

"Electric vehicles are an alternative to the existing combustion engine driven cars. According to the EU Battery Directive a substantial recycling rate of at least 50 wt.-% has to be met for aged batteries since 2006. Existing recycling techniques are based on energy intensive pyro- and hydrometallurgical process, which are not able to recover all components. Aluminum and lithium for instance are slagged. The EU-Project “ABattReLife” investigated possibilities for a mechanical processing in order to create a sustainable process and a closed material loop from grave to cradle. After a sufficient liberation of the Li-ion batteries, components like the doped carbon black fraction (mainly lamination of electrode foils), the separator foil and the housing material can comparatively easily be separated from the other components by screening and air sifting. The remaining mixture consists of anode and cathode foils which have a similar free-settling ratio and are more difficult to separate from each other. A second comminution and compaction step modifies the particle size and shape as well as the degree of delamination. These changes influence the density of the electrode foils in order to improve the separation efficiency. Yield and purity of the generated metal concentrates were parameters to show if the separation was successful. The specific energy consumption for the different methods of processing was estimated in order to benchmark the cost-benefit ratio for each one.The studies have been accomplished with a zig zag sifter (model TUBAF), a hammer mill (model HM 340 Jehmlich) and with a Petkus-Sifter. Finally a process flow sheet was developed for a Li-ion battery recycling plant in pilot scale."

Jan 1, 2016

By H. C. Rickaby

Introduction The township of Swayze, from which the Swayze gold area derives its name, is in the Sudbury mining division, approximately 150 miles northwest of Sudbury. The gold area may be regarded as situated at the southwest corner of a triangular area whose northeast and southeast corners are at Porcupine and Shiningtree, respectively, and whose sides are between 70 miles and 90 miles in length. On a geological map, it would be found that belts of Keewatin greenstones and sediments form the sides of this triangle, and that they surround a large granite mass. Prior to the summer of 1931 the Swayze corner of this triangle had probably been less prospected than the other parts and comparatively little was known of it from the standpoint of gold mining possibilities. The extensive belts of iron formation to the south and west of Swayze received some attention about the year 1909, and during the years 1927 and 1928 some prospecting was done in the townships of Greenlaw and Cunningham, south of Swayze, but chiefly for base-metals- copper, zinc, and lead. In the summer of 1931 a very promising discovery of gold-bearing quartz was made by J. G. and J. L. Kenty, working for the Brett-Trethewey Mines, Ltd., in association with Northern Canada Mining Corporation, and Northland Prospectors, Ltd., and this property, now known as the Kenty Gold Mines, Ltd., has been actively developed with very encouraging results. Following this discovery a6d during the summer of 1932 much prospecting took place in the area, as a result of which a number of other discoveries of gold were made, chiefly to the west of the original find. They are distributed over a wide area, which includes the townships of Rollo, Raney, Swayze, Denyes, Halcrow, and Greenlaw.

Jan 1, 1933

By Masami Nakamoto

Controlled thermolysis of gold(I) thiolate complex, [C14H29(CH3)3N][Au(SC12H25)2], at 180 °C for 5 h under an N2 atmosphere produces novel gold nanoparticles passivated by alkyl groups derived from the precursor complex, the TEM photograph of which shows spherical particles with average diameter 26 nm. Since Brust et al. reported the two-phase reduction of AuCl4 - by NaBH4 to afford monodispersed gold nanoparticles passivated by alkanethiolate ligands (1), plenty of preparative investigations on gold nanoparticles (2,3) and its surface modification (3,4) have appeared, because of their potential applications in microelectronics (5). However, those preparative methods generally involve the reduction of AuCl4 - by reducing agent NaBH4 in the presence of suitable organic stabilizers such as alkanethiol (1-4), phosphane (5), quarternary ammonium salts (6), surfactants (7) or polymers (8). On the other hand, O?Brien et al. recently reported the preparation of organically capped gold nanoparticles at 190 °C, where tri-n-octylphosphine oxide and/or n-octadecylamine are used both as a reaction medium and as a passivating ligand (6), but this procedure also needs NaBH4 as reducing agent. Our strategy of novel preparative method of gold nanoparticles is the combination of reductive elimination of thiolate ligands and simultaneous attachment of organic moiety on the growing nuclei. Gold(I) thiolate complexes with ammonium cations were useful for our preparative method. We now report the controlled thermolysis of gold(I) thiolate complexes, [R(CH3)3N][Au(SC12H25)2] and [R(CH3)3N][Au(SC6H4-p-R?)2] (R= C14H29, C12H25; R?= C8H17, CH3), under an N2 atmosphere, where the powder of gold(I) thiolate complexes completely melts to afford the precursor liquid and then the liquid gradually decomposes. In spite of no use of reducing agent and solvent, reduction reaction is thermochemically induced to afford novel gold nanoparticles passivated by alkyl groups rather than by alkanethiolate ligands. Figure 1a shows a typical transmission electron microscopy (TEM) image of gold nanoparticles prepared by thermolysis of [C14H29(CH3)3N][Au(SC12H25)2] at 180 °C for 5 h, indicating a controlled growth of spherical gold nanoparticles. As shown in Fig. 1b, these spherical gold nanoparticles display the size distribution ranging from 5 to 50 nm. Although the particle size is larger than that of thiol-derivatized gold nanoparticles (less than 5 nm) prepared by NaBH4 reduction (1-3), the aggregation of gold nuclei is smoothly regulated and the growth of core gold is limited to be 26 nm in average diameter in spite of thermal procedure.

Oct 1, 2003

By Miguel A. Cuba

Trends in the mean and/or variance are a longstanding challenge in mineral resource modeling. Geologic modeling and/or grade domaining are often employed to account for heterogeneities in mineral grades; however, this is only practical up to a certain point since the number of data available for reliable model construction can be severely reduced. In such cases, trends remain present in certain geologic/grade domains and directly impact the modeling methodology; the trend must either be handled explicitly or a suitable approach is adopted to implicitly account for it. This is highly dependent on understanding the source of the trend. We propose an approach that detects the source of non-stationarity, which is based on quantifying the impact of non-stationarity in the mean and the variance via the semivariogram. By expanding the methodof- moments approximation of the semivariogram, we decompose the experimental semivariogram is into three terms: 1) trend in mean component, 2) trend in variance component and 3) stationary component. We can then assess the source of trend by calculating the contribution of each component at every lag. Two cases are presented to illustrate this tool. Firstly, a synthetic reference model is simulated and different trend patterns are added; the influence of these patterns in the experimental semivariogram calculation are analyzed and discussed. Secondly, a real dataset is considered where the impact due to the presence of trends in the mean and variance are assessed. The results of this paper reveal the semivariogram to be a tremendously powerful tool in determining the source of the trend. This insight may be useful in the selection of a suitable modeling approach for resource estimation.

Oct 1, 2009

By L. Zhu, S. Kaierle, M. Dahmen, C. Zimmermann, T. Haubold, I. Kelbassa, C. Mattern

Application of integrally bladed disks (blisks) is of increasing interest in compressors of aero engines. Blisks are preferred due to their potential for size and weight reduction, for increased performance and for reduced manufacturing costs compared to conventionally bladed disks. In case of a damage the blisk aerofoils cannot be simply replaced. If the damage is beyond acceptance or blending limits refurbishment is possible only by scrapping the whole blisk assembly, or more cost effective by the application of advanced weld repair methods. Weld repair of blisk aerofoils is challenging as it affects a critical part with specific requirements regarding its mechanical integrity, and as the accessibility is usually limited. The paper describes the ongoing development of advanced weld repair processes as part of a comprehensive repair strategy which have been developed for small-sized blisk assembly to give competitive maintenance cost.

Jan 1, 2006

By Robert B. Parsons

"For the fourth time in five years, residents of northern Canada have seen a change in the tax treatment of housing and travel costs. The latest changes announced in December 1990 by the Minister of Finance are to become effective in 1991. When will the tinkering stop?IntroductionFor man y years prior to 1987, certain travel and housing allowances received by employees in remote areas were generally considered by Revenue Canada to be tax-free, even though some observers suspected that such generous treatment was contrary to the provisions of the tax legislation. In the mid-eighties, Revenue Canada decided to reconsider the tax treatment of the mining industry's long standing practice of providing housing and travel assistance to these employees. The tax- free treatment was continued by virtue of annual remission orders, but only pending the enactment of legislation which would tackle the issue head-on and layout the rules in black and white to be seen by all. The sequence of events since then may be chronicled as follows:February 26, 1986-Finance Minister Wilson's budget present s the framework for the future tax treatment of travel and housing benefits provided to residents in remote regions of Canada.December 22, 1986-The Minister of Finance announces detailed rules to fill in the earlier announced framework.January 1, 1987-The new tax rules come into effect.April 29, 1988-The Minister of Finance announces the establishment of a Task Force to examine the existing criteria for determining the eligibility of residents of northern and isolated areas for tax benefits.October 27, 1989-The Task Force presents its report.December 7, 1990-Finance Minister Wilson announces a new system of tax benefits for residents of Canada's northern and isolatedregions.January 1, 1991-The new rules become effective."

Jan 1, 1991

By A. Lawson

"Continued and expanded use of underground diesel-powered equipment is considered desirable in order to achieve necessary production capability, particularly when coal becomes increasingly in demand as an energy source. Although diesel engines are derated for underground use, concern has been expressed in many quarters regarding the health effects of worker exposure to diesel-generated particulate and NOx emissions. This concern will increase as Canadian diesel fuel quality becomes heavier and with higher sulphur content. This could result in a requirement to increase ventilation rates by 50%.This paper describes the results of studies of various approaches designed to reduce diesel emissions. Two major approaches have been followed: fuel modification, and emission control hardware development. The results of progress in the development of these approaches will be described.Fuel modification includes the application of water/diesel and methanol/diesel fuel emulsions to the engine. Details of the techniques employed in this approach will be described, together with the effects on diesel emissions. (The paper is concerned with the emission aspects only, not the possible major engine modifications and/ or substitute materials of construction for 100070 methanol.) Use of methanol has the added advantage of acting as a diesel fuel substitute and extender, and there are expectations that underground diesel engines could eventually operate on close to 100% methanol fuel, thereby eliminating particulate emissions. The results of emission control hardware development will also be presented and will include the effects of catalysts, water scrubbers, exhaust filters and exhaust gas recirculation techniques on emissions. A combined systems approach employing a number of these components appears to be the most viable method of controlling the complete array of diesel emissions.This work should culminate in a better understanding of the costs involved in employing fuel modification or emission control hardware relative to the costs of increased ventilation which mpy be necessary to maintain a safe working environment for the underground worker."

Jan 1, 1981

By Gerald S. Cole

It used to be that a science/engineering presentation on "light weight" at a metallurgy conference, would relate to the materials science, processing, component fabrication and applications of aluminum, magnesium and titanium. Within the automotive industry, light weight now includes how to "lighten up", how to lightweight, or how to mass reduce vehicle components and systems. Increasingly stringent global emissions-reduction requirements require increasing vehicle fuel efficiency; mass reduction is an enabler to achieve this. While light metals certainly are the basis, a host of other materials can be used to optimize mass reduction while meeting vehicle performance, safety and cost requirements. New grades of ultrahigh strength steels and even nanosteels can be thinned down and save over 1/3 the mass vs conventional mild steels. A compacted graphite cast iron engine can be made lighter than an aluminum one. Aluminum components in vehicles were only castings; now aluminum stampings, forgings and extrusions are becoming more visible components of mass reduction. Lower mass high temperature polymers, and carbon fiber polymer composites now replace aluminum and steel. These materials often require specialized processing and manufacturing techniques to produce a component, including superplastically formed twin roll cast sheet aluminum and magnesium, and hot stamped/in-mold quenched steels. The assembly of hybrid structures requires unique joining/bonding, and corrosion-inhibiting techniques that might include sophisticated structural adhesives. This thinking "light" presentation, will conclude with a discussion of U.S. and Canadian government engineering and research support for mass reduction, including the proposed $148 M American Lightweight Materials Manufacturing Innovation Institute.

Jan 1, 2014

By J. H. Douglas, A. F. Matheson

"The Hard Rock is the most easterly producing mine in the Little Long Lac area. The Company was formed in 1934 to develop a surface showing of gold in quartz made by a prospector, W. W. Smith, in 1931. Although some ore was eventually produced from this discovery, the principal orebody, hidden below 10 feet of muskeg, was found about 1,000 feet to the north by exploratory diamond drilling early in 1938 from the No. 2 shaft workings at the 250-foot level.Production started in 1938 and to January 1, 1947, 201,000 oz. gold had been obtained from 1,165,282 tons of ore mined and 869,397 tons milled. Of this ore about 15 per cent came from the development and mining of the original orebodies discovered at the surface. The remainder came from the ore found by the underground diamond drilling done in 1938. Of the latter ore, the Company estimated, at January 1st, 1947, only 140,000 tons remained. The orebody, therefore, contained approximately 1,100,000 tons.OREBODIES AND GENERAL GEOLOGYThe orebodies of the Hard Rock mine are of two main types: the quartz ore of the south and No. 1 shaft zones, and the sulphide ore of the north zone. The quartz ore consists of white quartz veins mineralized with sparse, fine, light-coloured pyrite, or, less commonly, nests of coarse, crystalline, light pyrite. A little tourmaline, scheelite, pyrrhotite, chalcopyrite, arsenopyrite, and native gold are also present. Native gold occurs in a few places in quartz veins in exceedingly rich cemcentrations, apparently where there are large, light-coloured, pyrite crystals of imperfect form. The ore of the north zone is massive pyrite with arsenopyrite and in places pyrrhotite. Many short irregular quartz veins, from a few inches to 2 feet in width, are also present, but the quartz forms a very small percentage of the whole. The veins may be flat to vertical, and sulphides on one or both sides replace the host rocks. The gold is closely associated with the sulphides . The quartz is commonly barren except where it contains sulphides or along the borders of the sulphide ore zone where native gold is not uncommon in quartz stringers."

Jan 1, 1954

By A. A. Paoli

The selection of a mining plant for carrying on development work presents many problems distinct in themselves, and affected by various local factors. In this paper, the writer proposes outlining and discussing in some detail the chief factors governing the economic selection of such plants. This will be followed by an enumeration of the underground and surface plant required for carrying on several hypothetical exploratory and mining operations. Where it is impossible or not convenient to obtain hydro-electric power, and where wood for fuel is scarce, we now find oil engines being used. A 100 h.p. oil engine, such as would be required to operate a three-drill air compressor, consumes approximately five Imperial gallons of fuel-oil per hour at full load. On the basis of a 60 per cent load factor, this gives, for eight hours' operation, a probable actual consumption of twenty-four Imperial gallons.

Jan 1, 1929