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By R. D. Brown

In view of the many changes which have taken place since 1950 in the rules of the Income Tax Act concerning the deduction of exploration and development expenses, many corporate taxpayers each year face the tedious task of determining which particular rules their unclaimed exploration and development expenses are subject to and in what sequence these expenses are to be claimed. Recent amendments to the Act have cleared up some of the mystery of the "ordering" of these deductions. This article examines the sequence in which various categories of exploration and development expenses are to be deducted in accordance with the terms of the Act as amended by Bill C-11.

Jan 1, 1978

By Robert J. McCarthy

There are two things on everyone's lips when mining folks gather these days - one is the exciting business opportunities that now exist for mine development and expansion, and the other is the dire shortage of human resources needed to design, manage, and even operate the mines. Years of stagnant industry growth, limited employment opportunities, and unwarranted perceptions of remote and harsh working conditions have caused mining to be a less than desirable career choice. Attrition and reduced entry to the workforce has resulted in shortages for not only mining professionals, but also skilled trades people and operators. Consequently, to survive, let alone grow, mining companies, suppliers, and educators are all pursuing innovative solutions with technology, inter-industry recruiting, centralized services, and strategic partnerships. This paper describes some of these initiatives and proposes others, now that the people are gone!

May 1, 2008

By D. G. Dixon

A novel technology for leaching copper from primary copper concentrates has been developed at UBC. This patented technology takes advantage of the galvanic couple between pyrite and chalcopyrite to ensure rapid and complete oxidation of chalcopyrite under mild conditions in acidic iron sulfate solution, without the need for microbes, ultrafine grinding, or chemical additives such as chloride, nitrate, or surfactants. Copper recoveries of 98% or greater can be achieved at 80°C under atmospheric conditions in as little as 4 hours of residence time. The process is selective for chalcopyrite over pyrite, generates near-quantitative levels of elemental sulfur, and is fully compatible with conventional solvent extraction and electrowinning of LME Grade A copper cathodes. In this paper, the fundamentals of the Galvanox ? process are reviewed, and selected results of batch leaching tests on various concentrate samples are presented and discussed.

Jan 1, 2007

Accountability for profit realized or lost, and responsibility for continued safe operation are the main impetus behind operator training. Efficiency in operation enables production at lower unit costs. An inefficient operation eats profitability of the operation, creating short term losses, and also affecting longer term viability particularly when commodity prices fluctuate and competition erodes market share. Safe operation and efficient operation are ultimately conjoined entities which may not be able to be sustained without dual effort. Training is a very valuable tool to engage operations in adopting more efficient and safe practices. Training requires time, facilities and trainers. One novel way of minimizing both the trainers and the facilities is through the use of Computer Based systems. Included amongst this are Computer based equipment simulators, following an identical philosophy as flight simulators used for pilot orientation and training for different aircraft types.

Feb 1, 2008

By M. A. N. Rosa, L. C. R. Machado, R. A. Fonseca, A. M. Mendonça

"Sossego Mine was the first Vale SAG mill operation to process copper-gold ore. It is located in the state of Para, in the south-eastern Amazon region of Brazil. In the first six years of continuous operation, Vale investigated different alternatives for improving circuit performance by investigating operating conditions, mainly focusing on the SAG mill.Today, after a steady increase over five years the annual production rate seems to have stabilized. It is hoped this work will show how the SAG operating practice have been perfected with time and as new data are collected. Historical data of mill grind-outs and crash stops helped create operation curves depending on the ball charge volume and total charge volume. Also noted were impacts on throughput due to the effect of reducing liner weight and the ore type characteristics."

Jan 1, 2012

By T. Hidayat

The distributions of minor elements between slag/metal and slag/matte in equilibrium with tridymite in the Cu-Fe-O-S-Si-Al-Ca system have been investigated in the range of conditions of interest to the high- temperature copper production, refining, and recycling processes. An improved experimental methodology has been used involving high temperature equilibration in controlled gas atmospheres, rapid quenching, and quantitative microanalysis techniques using Electron Probe X-ray Microanalysis (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrum (LAICPMS). The effect of oxygen partial pressure on the distributions of minor elements between slag/metal and slag/matte has been accurately measured. The effects of slagging components (Al2O3 and CaO) on the distributions of minor elements between slag/metal have also been experimentally determined. The present study is a part of a larger integrated experimental and thermodynamic modelling research program in the systems relevant to high-temperature copper processing. INTRODUCTION In the high temperature processing of copper, minor elements are distributed between different phases, i.e. liquid slag, liquid matte, and liquid metal. From a processing perspective, it is desired to have the valuable minor elements distribute predominantly in the metal and matte phases rather than in the slag phase, and to have the non-valuable minor elements distribute predominantly in the slag phase rather than in the metal and matte phases. Knowledge of the distributions of minor elements between phases in the smelting, converting, and refining processes is required if the distributions of minor elements between phases in these processes are to be optimized.

Jan 1, 2019

By Charles G. Kemsley

IN view of the truly remarkable development of special steels for special purposes, the mining industry has for years looked forward to a time when steel makers would come forward with a product which would be an improvement over the straight carbon steel which has always held the field for drilling rock. In order to avoid making changes in conventional shop practice, the industry has perhaps been too insistent upon obtaining a water hardening steel which could be handled in the blacksmith shop by long established methods. As early as 1932 or 1933, an oil-hardening tool-steel of the one per cent carbon, plus chrome, plus molybdenum type was applied to hollow drill steel. It was known as a hard as well as a tough steel, and one that, theoretically, should give a good account of itself as a rock drill, if properly heat-treated; and so it has proved in actual trials. There were numerous deterrents which retarded adoption of this steel. For several years there has been a constant improvement in the drilling qualities of the straight carbon steel, and, considering the higher unit price ? of the alloy, there has been considerable doubt in the minds of some mining? men as to what advantage there might be in the use of alloy over straight carbon for hollow drill steel. The alloy being an oil-hardening steel, its adoption meant having two kinds of steel in the mine, for a time, and that spelled trouble, unless some positive means of identification was adopted. The hardening and forging ranges of alloy steel being narrow also made necessary much closer control over these operations if poor results were to be avoided. These thoughts undoubtedly prevented its use becoming wide-spread, for, as a matter of actual record, less than fifteen per cent of all the hollow drill steel used in Canada today is alloy.

Jan 1, 1942

By E. G. C Charlesworth, M. J. Robertson

"Gold mineralization in the Main Reef Complex at Sheba Gold Mine is hosted within shear zones in a sequence of shales and greywackes of the Fig Tree Group. Competency contrasts between these rocks and a steeply dipping chert unit provided a locus for the development of right lateral steeply dipping shear zones. A set of flatter dipping shear fractures crosscut these zones with their intersections defining a system of en échelon ore shoots. Mineralization is both of vein type and disseminated strata-controlled replacement type. The latter occurs mainly within the wall rocks to the shear zones. Arsenopyrite and pyrite are the major sulfides, with arsenopyrite being confirmed largely to greywacke beds and pyrite to the more iron-rich shale units. Gold was introduced, together with minor sphalerite, pyrrhotite, chalcopyrite and early arsenopyrite, toward the end stages of a first pyrite phase. The mineralizing fluids were introduced along dilated cleavage planes and, emanating from these, produced a series of replacement fronts. Mineralization was syntectonic to late tectonic and occurred under conditions of progressive deformation, resulting in sulfides which are concentrated in the hinges of shear-related folds and semimassive sulfides within tension fractures which are folded, attenuated and fractured. An analysis of the structures shows a sequence of events in which an initial ductile simple-shear event with a steep sense of movement was succeeded by a more brittle strike-slip event. Mineralization is temporally related to the latter. This evolution in structural style was probably related to reactivation of the Sheba Fault as a transcurrent fault during emplacement of large granitoid bodies."

Jan 1, 1994

By W. Beres, R. E. Miller, B. Shiari, L. R. Zhao

A dynamic multiscale simulation method has been developed to study the material scratching processes on nanoscale single crystals. The model simultaneously captures the atomistic mechanisms near the free surface and the long range mobility of dislocations and their interactions, without the computational cost of full atomistic simulations. The method also permits the simulation of system sizes that are approaching experimentally accessible systems, albeit in 2D. Simulations are performed on single crystal aluminum to study the atomistic details, surface evolution, and generation and propagation of dislocations for a variety of scratching depths at room temperature. Simulations demonstrate the power of the developed method in capturing both long-range dislocation plasticity and short-range atomistic phenomena during tool advance. Variations of scratching normal and tangential forces are investigated and related to plastic deformation and dislocations generation during the simulation process.

Jan 1, 2006

By Z. M. Zavodni, C. D. Broadbent

"Major rock slides in open-pit mines are rare, but they can develop in spite of sophisticated slope engineering design practice. Experience has shown that, except under high seismic load conditions, the serious slope instability condition is almost always accompanied by the gradual development of one or more tension cracks behind the slope crest, allowing for time-displacement monitoring. Continuous surface displacement measurements with attendant prompt analyses are usually adequate for the prediction of slope behaviour.This paper describes efforts that have been made to quantify parameters associated with slide movement, and compares the displacement records of several large-scale open-pit porphyry copper mine slope failures. Two principal failure stages are recognized in the typical slope failure leading to total collapse: (a) REGRESSIVE STAGE, during which the failure will re-stabilize if some disturbance external to the rock and structure is removed; and (b) PROGRESSIVE STAGE. during which the failure will gradually displace at an accelerating rate to the point of total collapse unless active control measures are taken. Over-all displacement records in both failure stages are apparently of simple exponential form. with a definite break occurring at the onset-of-failure point.Certain common empirical relationships are suggested for the large-scale slope failures analyzed in this study. Based on plots of displacement rate vs time prior to collapse, a semi quantitative empirical relationship is presented for failure collapse prediction. The comparison of historical slide displacement records furnishes the operating engineer with practical guidelines to estimate the characteristics of future large-scale slope failures."

Jan 1, 1980

By W. Yang, R. Rajasingam, B. Tadesse, K. Mohanarangam

Copper electrowinning is a complex electrochemical process that involves the production of LME grade copper from copper rich electrolyte. The process involves the deposition of the copper ions onto the cathode from copper rich electrolyte with the production of oxygen bubbles at the anode. Acid mist is produced by these oxygen bubbles bursting at the electrolyte free surface. It is an undesired by-product of the Electrowinning process which unchecked could result in mist generation higher than the recommended time-weight-average exposure limit. Various approaches to alleviate the problem have been adopted by companies, all with varying degrees of success. All of these have been attempts to treat the symptom acid mist rather than the inherent problem, often proving expensive and, in some cases, ineffectual. In this paper, a new method was developed for acid mist quantification based on ‘total acid mist’ capture above the EW cell under well controlled conditions. With the use of sophisticated diagnostic analytical tools and measurement techniques it was possible to study all the operating variables including current density, flow rate, temperature, etc. independently and their effect on bubble size, bubble velocity, gas hold-up as well as acid mist generation and its droplet size. Results show that total acid mist capture increases with an increase in current density but remains more or less constant between 300–500 A m-2. Total acid mist also shows an increase with increasing electrolyte temperature. These findings are substantiated with the aid of bubble size and gas hold-up measurements with the transparent EW cell.

Jan 1, 2019

By V. Fiedler, H. Lachmund, R. Bruckhaus

"After producing some 50 million tonnes of crude steel the two BOF vessels at Dillinger Hüitte steel plant had to be replaced in 2000/01 due to large deformations. The new vessel design was optimised after a number of theoretical evaluations.Refractory investigations were carried out as well as temperature measurements of the shell to provide a basis for selecting a suitable steel grade. This was found in a DH-GTS development - P420M HT - with high strength at elevated temperatures and excellent weldability and made it also possible to build the vessel without any cooling system.After putting the first vessel into operation the metallurgical results showed no remarkable improvement compared to the old vessel, and were therefore not satisfying. With the help of cold model investigations the arrangement of the tuyeres was modified to improve the flow conditions and the interactions between oxygen jet and the heterogeneous plume of the bottom stirring gas. Further optimisations were obtained by a variation of lance tips and a newly developed lime addition model."

Jan 1, 2004

By Ron Hatch, M. K. Witte

"INTRODUCTIONThe proper selection of carbon for a gold carbon in pulp (CIP) circuit involves careful evaluation of several physical, chemical and economic factors. A series of evaluations are required to maximize gold recovery at the lowest capital and operating costs, whether the carbon is selected for an existing gold mill circuit or a new mill under design.Although evaluation may proceed through various stages, it is the intent of this paper to outline some of the preliminary testwork that should be carried out to screen potential carbons for a particular application.An examination of the specification sheets supplied by the various carbon manufacturers may indicate some desirable properties on which to make cursory selection. This exercise by itself will not provide the basic data needed for selecting the best carbon for a particular ore pulp and metallurgical circuit. The necessity of further metallurgical evaluation is indicated by the fact that different carbons perform differently depending on the physical and chemical nature of the leach pulp. In the case of an existing mill, actual leach slurries using mill water are available and should be used for testwork. In the case of new mills, leach pulps must be prepared to simulate the proposed circuit.Five coconut shell activated carbons were obtained from various suppliers, all reported to be 6 x 16 mesh carbons recommended for CIP circuits. A metallurgical evaluation was made utilizing two leach pulps with significantly different characteristics. This paper describes the test procedures utilized and the results obtained from the testwork."

Jan 1, 1985

By J. M. Turnbull

THE primary objective of the young graduate, after the war, will be to obtain a suitable position within the Industry, with adequate pay and opportunity to advance. The positions available to meet this demand will depend on the magnitude and organization of the industry. The size of the mining industry, in particular, will depend on a number of factors, including depletion; new discoveries of mineral deposits; beneficiation of new kinds of mineral deposits, based on research; technical improvements, also based on research, enabling the mining of lower grade deposits; and complex social factors. The organization of the industry will depend on its control and management, which may be greatly affected by social conditions and changes, and may include a wider or a narrower use of technical services. The corresponding training or qualifications of graduates, to meet these conditions, calls for a consideration of educational requirements and facilities in relation to the conditions that are likely to occur. Some forecast of the probable future of the Industry, after the war, based on consideration of. the above factors, is necessary as a basis of discussion, since the graduate must find his place in the industry of that time, and find his work in maintaining and improving it, within the existent social framework. Social factors are pressing and? important at present and their future impact is uncertain. In considering these, a few quotations and extracts may be in order. "A new economic order, based on free access to the sources of raw materials, means free use of the world's wealth by all civilized nations" (The Pope. Also advocated by Churchill and Roosevelt in the Atlantic Charter). "Every citizen should have a voice in the conduct of business or industry which is ?carried on by means of his labour" (Archbishop of Canterbury).

Jan 1, 1943

By M. Y. Williams

Introduction During the economic investigation of Pacific Great Eastern Railway subsidy lands, the P.G.E. Survey of Resources made a geological and mineral survey of a large part of the valley of the Peace river as included in the Province of British Columbia. The immediate valley of the Peace river was surveyed from the mountains to the Alberta boundary; the valley of the Pine river was surveyed throughout; and the Dominion block, 70 miles square and lying astride the Peace river, westward from the Alberta boundary, was very carefully surveyed. The writer was in general charge of the field work, and spent half the field season of 1929 and the field season of 1930 in the region . J. B. Bocock, however, did the major part of the work, spending two seasons, 1929 and 1930, in the area. General Conclusions The rock formations within the area discussed are all sedimentary and range in age from pre-Cambrian to recent. As might be expected, the minerals are in the main non-metallic, coal being by far the most important. Favourable conditions exist for natural gas occurrence, and suitable structures for petroleum concentration occur, although the high carbon ratio of the coals sheds considerable doubt upon the actual occurrence of oil in the area. Materials of minor interest are ochre, calcareous tufa, marl, limonite, gravel, and building stone.

Jan 1, 1934

By Irvine J. Berscheid

This paper describes a rock drill bit which, although conventional in the processes of manufacture and use on the job, has incorporated into the outer wall or periphery of the insert, where wear is always the greatest, a variable amount of extra metal, distributed in units of height of insert to withstand this excessive wear. Explained are variations of construction, how the extra metal enables the bit to drill more footage, prevent antitaper and the need to gauge grind, increase penetration rate and the length of run per regrind, reduce shank breakage and ma-chine costs, and permit increased production per man-shift, without requiring any change in equipment already on the job. F OR purposes of clarity, reference to bits here means integral rods or multi-winged bits which have their inserts sharpened to a conventional shape. When dull, the insert has worn, on its face, a flat which increases in width as we progress from near the center of the bit toward the outer edge. Very

Jan 1, 1965

A line of nine self-aspirating W emco cells, part of the Rougher circuit at Division Salvador, Codelco Chile, was retrofitted to allow operation with forced air. Each cell could be operated self-aspirated or with compressed air supplied through a 4-inch line equipped with a mass flow meter. Gas dispersion was characterized for the two modes of operation. Metallurgical performance was compared under self-aspirated conditions and with different gas profiles under forced air conditions. Cell characterization demonstrated that with forced-air the cells could not evenly distribute air across the cell volume. Bubble size increased with gas velocity, as expected, with no difference between self-aspirated and forced-air operation. A systematic increase in bubble size down the bank was found. Cumulative bubble surface area flux down the bank showed no major differences between surveys. However, grade-recovery curves revealed that the highest recoveries were invariably obtained with forced air operation. Plotting concentrate mass recovery vs. enrichment ratio showed that the line performance could be controlled over a wider range when forced air was used.

Jan 1, 2007

By Mauro Chiesa

A. New Dictionary, Since 2007/8 Traditional concept of ?cycle? is dead A dearth of projects AND good metal prices suggests otherwise In a depletion-business, good times for any greenfields in 2-3 yrs! ?Balance? sheet means quality assets = quality capital So, de-risk the assets, and ration the capital ?Replacement costs > historical costs ?Discounted assets depleting; replacement costs need self-financing (FCF) ?Public-sector slows permits, avoids assets and wants more of FCF ?Capital ?markets? are now ?market fragments? ..and? ??Shareholder? has changed from ?growth? to ?income + performance? ?Higher search costs, higher capital costs and higher cost of capital

May 1, 2013

By James D. Bliss, David M. Sutphin

"On the basis of differences derived from genetic, descriptive, and grade-tonnage data, graphite deposits are classified here into three deposit types: disseminated flake, amorphous (microcrystalline), or graphite veins. Descriptive models have been constructed for each of these deposit types, and grade-tonnage models are constructed for disseminated flake and amorphous deposit types. Grade and tonnage data are used also to construct grade-tonnage models that assist in predicting the size and grade of undiscovered graphite deposits. The median tonnage and carbon grade of disseminated flake deposits are 240 000 tonnes and 9% carbon and for amorphous deposits, 130 000 tonnes and 40% carbon. The differences in grade between disseminated flake and amorphous deposit types are statistically significant, whereas the differences in amount of contained carbon are not .IntroductionIndustrial minerals, including mineral construction materials such as sand, gravel, and crushed stone, have historically exceeded metals in global production value. Today, industrial minerals are being used in new and sophisticated ways in response to the late 1980s emerging information- and service-based economies' requirements for less metal and more industrial minerals . Natural graphite is an example of one such mine ral that has been known since ancient times, and is now finding new applications. Graphite was first used as an industrial mineral in Bavaria in 1400 A.D. where it was an important component of crucibles. Traditionally, natural graphite has been used in heavy industries. New applications, such as development of carbon-magnesite bricks a decade ago and the current advancement of alumina/graphite refractories, are increasing its graphite use. Other new uses for natural graphite, such as the use of graphite powder as a thermal blanket for the continuous casting o f steel (Northern Miner, 1987) and the addition of expanded graphite to polyurethane foam where it acts as a flame retardant (Industrial Minerals, 1987), are increasing the demand for this mineral. To meet future demand for graphite and other industrial minerals, knowledge of the characteristics of the deposit types in which they are found is important. A further look at the deposit types for graphite and at construction of descriptive and grade-tonnage models is warranted .The graphite industry recognizes three basic types of graphite , distinguished primarily on the basis of grain size: crystalline flake, lump and chip, and amorphous. These naturally occurring forms of graphite are products of metamorphism and are found in schists of various types, gneisses, and marbles. Temperatures of at [east 400°C are thought to be required for graphite formation (Landis, 1971). Synthetic graphite, also known as artificial or manufactured graphite, is a man-made carbon product and offers higher purity and lower crystallinity than natural graphite. Several authors have written about graphite's unique physical and chemical properties and the uses for individual types of graphite (Krauss et 01., 1988; Graffin, 1983; and Harben and Bate s, 1984)."

Jan 1, 1990

By P. Molera

"In Catalonia, between the 10th century and 1878, some installations were developed which at first were called ""factories"" and later ""fargas"", since they manufactured iron and steel of low carbon content. Because of its excellent quality, the fame of this metal spread from Catalonia to many countries. Fargas were started in Corsica, the Low Countries, Germany, Oriental India, Madagascar, Finland and along the rivers Orinoco and Mississippi among others. The extractive process used in these fargas has passed into history as the ""Catalan Farga Process"", ""Catalan Process"", or just ""Farga Catalana"". With this technology, raw material was obtained for the fabrication of tools, nails, weapons, grilles, etc. to supply the national and export markets. Aside from meteorites and native iron, found as metallic nodules in basalts in Greenland and Palestine, the ancient civilizations, which had no means to reach the fusion temperature of iron (1535°C), obtained iron by a direct process. Similar processes were used until quite recently (1930s) by certain tribes in Central Africa; holes in the ground were filled with iron ore and coal, and combustion encouraged by blowing air by mouth or with bellows made of animal skins. Thus without melting the iron it is possible to reduce the mineral and obtain a porous and impure metallic mass, which is purified on forging by mechanical squeezing. With a process very likely similar, the famous column at Dehli weighing 6.4 m.t. was built about 300 B.C."

Jan 1, 1999