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By Liang Zhen, Jian-Tang Jiang, Guo-Ai Li, Xiao-Ya Wang

"Deformation behavior of 2A97 aluminum alloy containing coarse secondary phases was studied using uniaxial hot compression (HC, 340–490°C, 0.4001–1 s-1). The flow stress could be described by a Zener-Hollomon parameter in hyperbolic sine function with the hot deformation activation energy of 237 kJ/mol. Based on the experimental data and dynamic materials model, processing maps were generated to demonstrate the hot workability of the alloy. The coarse secondary phases experienced dissolution by varying degree under different deformation temperature, which producing different effects on the microstructure evolution. When deformed at relatively low temperatures, a mass of fine grains shaped up in the original grains and grain boundaries, and the dominating deformation mechanism was believed to be dynamic recrystallization. As the deformation temperature rising to 490°C, most secondary phases disappeared and few recrystallized grains were observed, indicating that the secondary phases dissolved sufficiently along with dynamic recovery occurred during the hot deformation. Particle stimulated nucleation related to the coarse secondary phases was believed to promote the recrystallization and the recrystallization behavior was sensitive to deformation temperature.INTRODUCTION Al-Li alloys has received much attention as new promising structural materials in the aircraft and aerospace industries, due to their lower density, higher elastic modulus and improved fatigue crack growth resistance in comparison with the conventional commercial aluminum alloys (Ou Ling, 2015). 2A97 alloy is one of the 3rd generation Al-Li alloys targeting at comprehensive improvement of aviation aluminum alloy and applications for wing spars and ribs to other internal structures for transport aircraft. Al-Li alloys are usually formed by hot deformation, either by rolling or extruding. The deformation behavior and resulted microstructure evolution during the forming process mainly dominates the formability of the alloy and the serving performances as well. Therefore, the deformation behavior and microstructure evolution at elevated temperature need be made clear for optimizing the hot processing parameters and controlling microstructure evolution."

Jan 1, 2018

By Charles Graham

It is the general belief that the coal deposits on Vancouver Island are extremely large, and easily available. Indeed, they are frequently described by prominent public men and by writers in the press as "illimitable" and "inexhaustible." It is well that the facts that have been established as a result of seventy years of surface prospecting, underground operations and extensive diamond-drilling in this coalfield should be disclosed. HISTORY The presence of coal on the coast of British Columbia was first made known by Dr. W. F. Tolmie in 183 5. This coal was brought to him by Indians from the north-east coast of Vancouver Island, probably from Suquash. In 1850 the existence of coal at Nanaimo was announced by Mr. ]. W. MacKay. Development was started in 1852, and coal was shipped before the close of 185 3. The first operations were carried on by the Hudson's Bay Company, who operated the mines until 1861, when they sold them to the Vancouver Coal Mining and Land Company. Practically all of the operations in the immediate vicinity of Nanaimo have been carried on by this Company and its successors. In 1869, Mr. Robert Dunsmuir discovered coal about five miles north-west of Nanaimo, at Wellington. The Welling-ton Colliery Company was organized, and began to produce coal from the Wellington mines in 1871, the coal being shipped from Departure bay. This colliery was a large producer for several years, but was finally closed in 1900.

Jan 1, 1924

By A. M. Richmond

Introduction The apparent commonplace, and prosaic, nature of building-stones, lime, cement, gypsum, and clay products, and many other miscellaneous non-metallic minerals, such as abrasives, barite, diatomite, magnesite, mica, slate, salts, etc., and their everyday appearance and necessary in our lives, has removed much of the glamour, romance, and speculative attractiveness so frequently associated with our gold, silver, lead, zinc, and copper mining ventures. However, it will be readily appreciated, with but a brief study of the thirty-five or more non-metallic minerals and products which are mined, prepared, or are known to occur, in British Columbia, that the 'industrial minerals' industry in the Province has an abundance of interesting technical problems, is fraught with speculative possibilities, and, as such, fully deserves much more technical attention than it has hitherro received. The brief notes presented in this paper show, in summary form, the magnitude of the British Columbia industrial and non-metallic mineral industry; outline in synoptically form the principal deposits of non-metallic minerals presently known; and indicate in a general way a few of the possibilities which exist in the Province for the expansion of the industry. For convenience in presentation, the assembled material has been divided into four sections: 1.-Sraristical information 2.-Strucrural non-metallic minerals 3.-Miscellaneous non-metallic minerals 4.-Non-Metallic mineral possibilities in British Columbia 1. -Statistical Information The writer does not propose to dwell at length on the statistical comparisons and deductions which may be drawn from the four tables which have been compiled for this section of the paper, nor is it considered essential, as the figures present a most emphatic story in themselves.

Jan 1, 1935

"This contribution is concerned with adaptive processing decisions, where the process parameters are optimally adapted to the varying properties of the material input stream. Our starting point is the geometallurgical paradigm that the varying properties of the input stream are considered known e.g. from a geometallurgical model of the mined ore body, and optimal processing parameters are computed from them, by finding the parameter seaming optimal in a computer simulation.This approach however has to work with a lot of uncertainties: The prediction of the geometallurgical ore parameters can only be done with some geostatistical uncertainty. The parameters themselves are only proxies for true ore properties. Model prediction can differ relevantly from actual process results, due to model simplifications. Due to these uncertainties the computed processing choices can turn out to be inferior to simple non-adaptive processing. In this contribution we focus on the uncertainty of the ore properties and analyse this effect systematically, by modelling this uncertainty effect mathematically and in computer simulations. The most important findings are:(a) Processing choices not taking into account the uncertainty sometimes even perform worse than simple non-adaptive processing, for the sole reason of ignoring the uncertainty effect.(b) Ore properties, not adequately reflected in the ore description, might require different approaches, in which the observed processing behaviour feeds back into process control.(c) Bayesian decision theory allows computing optimal processing choices combining the information from the mine (geostatistical predictions) and from the process feedback. These choices give much more robust choices and do not suffer from the drawbacks described for the simple approach we started from.These new approaches can substantially improve the performance of adaptive processing in existing plants."

Jan 1, 2016

By Parviz N. Farsangi, Ferri P. Hassani, Allen G. Hayward

"Kidd Creek Mines places approximately 10 000 tonnes of consolidated rockfill (CRF) daily. Consolidated rockfill comprises sized aggregate mixed with different ratios and amounts of binders. Consolidated rockfill is employed to simplify subsequent pillar recovery and provide improved passive/active ground support.The consolidated rockfill is designed to sustain not only the gravitational loading of the overlaying fill material, but also to some extent the dynamic loading applied during blasting of the adjacent stopes and/or pillars. This paper describes the steps taken to optimize the pre-sent fill system at Kidd Creek Mines.The emphasis is on four areas which have high saving potential: lower cost alternative binders, structural design, quality control measures, in-situ testing techniques for back analysis. A consolidated rockfill design optimization chart was developed from these investigations."

Jan 1, 1996

By D. C. Peck, H. D. M. Cameron, N. M. Halden, L. S. Jobin-Bevans

Abstract-The late Archean Pipestone Lake anorthosite complex (PLAC) is a 0.9 x 17 km sill-like layered intrusion that is part of a suite of coeval megacrystic anorthosite bodies in the Cross Lake region, northwestern Superior Province. Exploration for Ti-V-Fe oxide mineralization and concurrent geological investigations have contributed to a greater understanding of the lithostratigraphy of the PLAC and its oxide mineralization. Mapping and drill core studies have established a laterally continuous igneous stratigraphy comprising six leucogabbro/anorthosite zones and three melagabbro/gabbro zones. Field evidence, including disrupted blocks of layered units, scour contacts, and size-graded and modally-graded layering, suggests younging towards both the northern and the central parts of the complex. A decrease in the anorthite content of the feldspars from An75 in the south to An30 in the north suggests that the magmas become more evolved to the north. Macrorhythmic layering and gross morphological features suggest that the PLAC crystallized from four major influxes of geochemically similar basaltic magmas. The paucity of magmatic erosional features in the PLAC indicates that layering developed in a relatively static magma chamber, so that in-situ crystallization processes are required to account for the observed petrologic diversity. Drilling has confirmed that a significant Ti- V-Fe resource is contained in two of the four discrete mineralized subzones in the PLAC. Textural evidence and the stratiform nature of the oxide-enriched subzones are consistent with a magmatic origin for the oxide mineralization.

Jan 1, 1997

By Tapio Leskinen

"In the 1960’s, when large flotation machines appeared on the market, this was a part of a world-wide trend towards the use of ever larger machine units.One factor that has played a decisive part in this development is the increased of the amounts of ore that have to be handled as the exploitation of successively poorer ores becomes necessary. The advancing application of instrumentation and automation has worked in the same direction.In 1970, a working group was set up within Outokumpu Oy, for the purpose of flotation machine development. The principal task of this group was to be the design and development of- a new type of rotor of increased efficiency, especially for the dispersion of large amounts of air- a mechanical-pneumatic flotation machine of substantially larger size that existing plant.This development project required an extensive program of theoretical investigation and experimental studies at several concentration plants of the company.The commonest flotation machine presently used in the concentration plants of Outokumpu Oy is the VK-3. It is of the mechanical-pneumatic type, and the volume of its cell tanks is 2.5 m3 per shaft. This machine was developed within the company, and its first development phase i s represented by the OKKO 3, built for the Kotalahti concentrator in 1959. It was, in its time, comparable in volume to the largest machines that were then in use anywhere in the world."

Jan 1, 1976

By Y. Serres

In the past, conventional reflection seismic techniques were not very successful when applied to typical mining exploration: they lacked resolution in the shallow range or were not cost effective. By combining a light earth tamper source, special geophones and field procedures, a stacking process of the returning seismic events using a microprocessor system, and a sophisticated sequence of adapted digital data processing, Mini-Sosie achieves high resolution in the 100-ft to 4000-ft range. Additional advantages result from the very quiet nature of the source and flexibility of the system. Although Mini-Sosie might be used in the refraction mode, or for well velocity logging, it has found its main applications with the reflection technique.

Jan 1, 1978

By S. A. H Tyrrell, R. Rotzinger

"Taseko Mines Limited recommenced operation of the Gibraltar copper-molybdenum mine in 2004 and embarked on series of development projects to modernize the mine and increase throughput capacity. The Gibraltar Development Plan 3 (GDP3) project included a second stand-alone copper-molybdenum concentrator, a stand-alone molybdenum separation plant and associated services. Ausenco was contracted to commence the detailed design in 2Q2011, commissioning commenced in 4Q2012 and first ore was processed in 1Q2013. This paper discusses the design, implementation and commissioning of the GDP3 Concentrator.INTRODUCTION The Gibraltar Mine (Gibraltar) property is located in the Cariboo Region of south central British Columbia, approximately 360 kilometers northeast of Vancouver. The site is accessed via an 18 kilometer paved road from the town of McLeese Lake, which is located on the province’s main north-south highway between the cities of Williams Lake and Quesnel. Gibraltar was originally developed by Placer Development and commenced production in 1972. Gibraltar was acquired, while on care and maintenance, by Taseko Mines Limited (Taseko) in 1999 during a period of unusually low metal prices. Taseko recommenced operations at Gibraltar in 2004, and embarked on series of development projects to modernize the mine and increase throughput capacity. The 1972 Gibraltar process flowsheet incorporated two-stage crushing followed by rod and ball milling and flotation. In 2008 Gibraltar completed their first development stage that included the installation of a SAG mill, converting the existing rod mills to ball mills and adding additional flotation capacity. Gibraltar continued development with the installation of an in-pit primary crusher, expansion of the bulk regrind circuit, expansion of the cleaner flotation circuit, replacement of the tailings pumping system and replacement of the concentrate filters and dryer."

Jan 1, 2014

By J. F. Wright

Introduction Previous to 1924 the mining fields of Manitoba and adjoining territory had not been prospected in detail, and the reports of the exploration of the mineral discoveries to that date had been discouraging. As a result of the apparent failure of all the mining operations, some considered that geological conditions in the country westward from lake Superior extending across western Ontario, eastern and northern Manitoba, and northern Saskatchewan, were different from those in the northeastern part of Ontario, where large gold mines had been developed. Discoveries of importance thus were necessary to renew interest in the mining possibilities of this part of the Canadian Shield, and the successful operations at Flin Flon and Howey in large part were responsible for the beginning of the present activity in what may be described as the part of the pre-Cambrian Shield within central Canada. In Manitoba, the more important developments at present are in the Central Manitoba, Gods Lake, and Knee Lake fields. The large area from west of Flin Flon east to Herb Lake, also, is being explored carefully for gold deposits of merit. A number of properties in Red Lake, Woman Lake, and Pickle Crow areas are being drilled and explored underground. Many of the mines of the Lake of the Woods area, that were producing gold 30 years ago, are re-opened, and new prospects in this field and in the country to the east are being explored. The recent development of Little Long Lac mine in an area near the railway, and considered by some to have been thoroughly prospected years ago, has stimulated interest in the areas formerly prospected. In the autumn of 1934, the belts of greenstone and sediments in the country east of lake Nipigon were staked, and deposits in these fields will be explored in detail this year. This paper is presented to discuss the general features of the geology and gold deposits of the various prospecting fields in Manitoba and adjoining territory. Details of a number of the areas and mines will be presented at this meeting in papers by Barton on Little Long Lac, Tanton on Sturgeon River, Baker on Gods Lake, and Brownell and Kinkel on Flin Flon. Although mining was not active in most of this territory previous to 1930, geologists of the various government departments continued field studies and interesting reports were issued.

Jan 1, 1935

By W. S. Hargratt

THE present era of exploitation of the Little Long Lac and Sturgeon River areas commenced in 1925, when Beardmore Gold Mines started development of what is now the property of Northern Empire Mines. A shaft was sunk in 1927-28 and a very limited amount of underground work was carried out, following which the property was shut down. It remained idle until 1932, when Empire Star Mines, a Delaware Company, optioned the property. This Company formed the Northern Empire Mines Company, Limited, to operate the mine, and immediately instigated an aggressive programme of surface and underground development. By the summer of 1933, sufficient ore was indicated to justify the installation of a small mill. The decision was also reached to bring in electric power. A power-line was built from Hydro, the Ontario Power Commission's development on the Nipigon river, to the mine, a distance of approximately 50 miles. This work was entirely financed by Northern Empire Mines. Mill construction was commenced in October, 1933, and completed by March, 1934, thus making this mine the first producer in this district.

Jan 1, 1940

Barrick Gold Corporation is the gold industry leader, with 25 operating mines and a pipeline of large, long-life projects located across five continents, in addition to large land positions on some of the most prolific mineral districts. Barrick's high level of commitment to sustainable economic development and environmental stewardship was recognized by Dow Jones Sustainability Index (DJSI) - World, for the third consecutive year in 2010. The potential for adverse environmental effects from acid rock drainage (ARD) and metals leaching (ML) and their financial implications for Barrick are key considerations in our environmental assessment and business development processes. Barrick's membership in the International Network for Acid Prevention (INAP) reflects the importance of these issues to our business. INAP's development of the Global Acid Rock Drainage (GARD) Guide (a best practices guide for acid rock drainage prevention) provides Barrick with an important tool to assist in the assessment of environmental and financial risks from ARD and ML associated with our planned and ongoing mining operations (INAP, 2009). In this paper we will discuss how Barrick incorporates the GARDGuide and its principles for ARD and ML prediction and prevention in our business development processes and the management of our operations. The GARDGuide serves as a key reference for our project environmental assessments and as a common link between our projects and operations management, consulting specialists, permitting and regulatory authorities and the public. We will discuss how the GARDGuide is being "syndicated" throughout Barrick as a standard of practice and present a case study of how it was used in a recent Barrick Business Development Project.

Jan 1, 2011

By Michael McClintock, Bern Klein

"The high pressure grinding roll (HPGR) is a relatively new comminution technology that is gaining popularity for providing energy efficient solution to hard rock mining operations. A significant barrier to increased adoption of HPGRs is the present requirement for large amounts (excess of 2 tonnes) of sample for pilot testing, which may not be possible for most early stage projects. Three methodologies have been developed at NBK Institute of Mining Engineering at the University of British Columbia that may be used for sizing design optimization of HPGR circuits. All three methodologies use a MTS pistonpress to simulate HPGR comminution. These tests are capable of providing information regarding energy consumption, energy breakage relationship, reduction ratio, and product size distributions. In a period of slow economic development, these methodologies are critical to allow the industry to cost effectively understand the operational benefits of HPGR implementation. This paper examines previous test work done at UBC, as well as the development of an HPGR and piston press database for use in sizing and budgeting of HPGR circuits.INTRODUCTIONCurrently, the mining industry faces several challenges due to falling commodity prices and escalating costs. This has applied pressure for operations and projects to reduce costs and improve project economics. In addition engineering and metallurgical budgets have shrunk as companies try to conserve cash. Improvements and optimization of milling and comminution circuits is one area project economics may be significantly improved. By considering alternative comminution technologies such as the high pressure grinding roll (HPGR), energy operating costs may be greatly lowered. Many have begun to implement HPGR crushing as an alternative to semi-autogenous grinding (SAG) mills, including KGHM and, Sierra Gorda, and Freeport Mc-MoRan’s Cerro Verde operation. However, implementing new technology for companies with little or no HPGR experience may not be practical. An operator must consider both feasibility and economics of a circuit. Currently, consideration of the HPGR requires expensive pilot scale testing for which large sample sizes are needed. In addition, few laboratories are equipped for running pilot scale HPGR test programs. Furthermore, the results of pilot HPGR testing are dependent on the quality of the sample, which cannot represent variations across a deposit. In contrast, ball mills and SAG mills can be sized using the Bond Mill Work Indexes that require a small amount of sample which enable a number of different geological blocks to be tested to allow engineers to have a complete understanding of how the comminution circuit will perform for the life of mine."

Jan 1, 2016

By D. K. Sarkar, Ying Huang

"Superhydrophobic thin films were fabricated on aluminum alloy substrates by chemical etching followed by passivation with organic acid molecules; (ii) electrophoretic deposition (EPD) of functionalized ZnO nanoparticles and (iii) electrodeposition of organic-inorganic composite materials. The physical and compositional analyses of the deposited thin films were characterized by SEM, FTIR, XRD as well as contact angle goniometer. The contact angle and surface roughness of the superhydrophobic surfaces prepared by the chemical etching process were found to be 156° and 2.29 µm, (ii) by the EPD process were found to be 155° and 4.54 µm and (iii) by the electrodeposition process were found to be 159° and 7.11 µm, respectively.The corrosion properties were analyzed with both polarization and electrochemical impedance spectroscopy (EIS) in NaCl aqueous solutions. The results demonstrate that the superhydrophobic thin films on aluminum alloy substrates display better anti-corrosion behavior than the as-received aluminum substrate. The comparison of results pertaining to the compositional and corrosion properties of these thin films on aluminum will be discussed in this work.INTRODUCTIONSuperhydrophobicity is defined as a surface property which provides non-wetting characteristics with a water contact angle larger than 150°. It is observed that the creation of certain micro-nanoroughness structures promotes the entrapment of air in the spaces of the rough surface morphology. In addition, lowering the surface energy helps to reduce the affinity of water drops to the surface, thereby weakening the water-surface interaction. Recently, various fabrication methods for superhydrophobic surfaces have been explored (Sarkar, 2010, Huang, 2010, 2011, 2013, 2015a, 2015b), such as the sol-gel process (Brassard, 2011), plasma treatment (Marchand, 2013), chemical vapor deposition (Zheng, 2009), chemical etching (Saleema, 2011), electrodeposition (Ying, 2011) and electrophoretic deposition (EPD; Huang et al., 2015b)."

Jan 1, 2016

By P. G. Killeen

Proper calibration of portable gammaray spectrometers and spectrometric logging equipment is essential if they are to be used for accurate quantitative determinations of radioelement concentrations. In the case of both types of equipment, it is necessary to determine the system calibration constants (stripping factors and sensitivities). In the case of borehole logging equipment, it is further necessary to determine the system response characteristics if the data are to be computer processed to improve the accuracy and resolution of the logs. Facilities are now available near Ottawa for the complete calibration of portable gamma-ray spectrometers and spectrometric logging equipment, in addition to already existing facilities for calibrating airborne gamma-ray spectrometers. Limited additional facilities are also available or planned in several other areas of Canada.

Jan 1, 1978

By M. El Tokhi, H. Arman, B. M. Amin

"This paper aims to overview some mechanical and physical features of the gabbroic rocks. The study has two phases: filed study/in-situ measurements and laboratory work. During the field studies, rock block samples were collected from different locations of the study area to represent the different types of the gabbroic rocks. Either core or rock samples for various tests were prepared from rock samples taken to the laboratory. The unconfined compressive strength (UCS), indirect tensile strength (ITS), point load index (PLI), Schmidth hammer rebound value (SHV), slake durability index (SDI), sonic velocity (SV) and unit weight (UW) test were carried out either on the selected rock block samples or core samples.INTRODUCTIONThe geology of the United Arab Emirates (UAE) has been divided into three major rock units (Lippard et al., 1986); an autochthonous succession, allochthonous units composed mainly of Mesozoic rocks and include the Sumeini Group (concomittent slope sediments), Hawasina Complex (basinal sediments) and the Semail ophiolite nappe (massive slice of former oceanic crust), that were emplaced as a series of thrust nappe in the Late Cretaceous and Neo-autochthonous sequence of Maastrichtian and Lower Tertiary sediments.The Semail Ophiolite (600 km long and up to 150 km wide) is thought by some authors (Glennie et al., 1990) to have been generated along a subduction related back-arc spreading axis during the Cenomanian-Turonian and was obducted onto the Arabian continental margin during the Campanian. Others, however, consider it to represent a primitive arc-spreading center related to oblique subduction Lippard et al., 1986). The Ophiolitic rocks in the study area comprise mantle and crustal sequences. The mantle peridotite and crustal gabbros are the dominant rock types of the exposed Semail Ophiolite north of the Hatta zone. This paper is only concentrated on the gabbroic rocks."

Jan 1, 2015

By S. Kline

The compositions of metamorphic minerals of the south limb of the Dore Lake Complex have been determined by microprobe techniques. Mineral assemblages typical of the greenschist facies occur in Mg-rich bulk compositions, but in Fe-rich rocks albite-epidote amphiboli te facies assemblages occur. Low oxygen fugaci ties and a general paucity of metamorphic fluids prevailed in most of the complex, but a higher oxygen fugacity is indicated near the Chibougamau Pluton, and a local abundance of C0z and Cl in fluids near the pluton is suggested by the presence of scapoli te. The metamorphic gradient overprinted on the complex near the Grenville Front is apparent in mineral chemistries as well as by the appearance of garnet. Chlorite becomes richer in Mg, and iron is fractionated more strongly into hornblende. The amphibole also increases in Alz03.

Jan 1, 1984

By Ryan Montpellier, Paul Hebert

"Prospecting the Future: Meeting Human Resources Challenges in Canada's Minerals and Metals Sector is a comprehensive sector study of the short- and long-term human resource issues and challenges facing the minerals and metals industry. The study's in-depth assessment of current and emerging human resource needs and gaps served as a foundation for the recommendations designed to maintain the strength of the minerals and metals sector well into the future. The study provides insight and identifies strategies relating to each of the following areas:•,An aging workforce•,Significant retirements on the horizon•,Human resources demand growth•,Supply challenge - education and training programs•,Under-representation of non-traditional groups•,Supply advantage - attractive features of mining•,Supply and demand gap"

Jan 1, 2007

By Walter I. Nelson

THE geology of the Copper Mountain mine has been ably described by Dr. Victor Dolmage in Memoir 171 of the Geological Survey. Reference is invited to that paper for a more extended description of the geology of the ore deposits than will be given here. The important orebodies of the mine occur in fragmencal volcanic rocks, parallel with and adjacent to the gabbro of the Copper Mountain stock. In the mine area, the contact strikes N.45°W. and dips either vertical or steeply co the southwest. For a distance of 500 feet or more from the contact, the fragmental rocks have been intensely metamorphosed both dynamically and hydrothermally. The dynamic effects are reflected in the foliation and fracturing parallel with the contact, which occurs throughout the mine, and the volcanic rocks within this foliated zone are, in places, highly schistose. Superimposed upon thi.s structure is a system of fine, straight, parallel frac-tures that strike nearly normal to the foliation (and contact) and dip between 65° and 75° to the north; it is with this last-described fracture system that the ore minerals are structurally associated. The fractures are mineralized with bornite and, to a considerably less extent, with chalcopyrite and some pyrite. A notable characteristic is the extreme fineness of the fractures; even in high-grade ore they are rarely larger than pencil lines. The tenor of the ore, therefore, varies directly with the fracture spacing. Replacemcnr of the host-rock between two or more fractures, varying in degree from finely disseminated sulphides to masses of nearly solid bornite up to 18 inches wide and 2 to 3 feet long, is not uncommon in the higher-grade portions of the orebodies. Two structural types of orebody are recognized in local nomenclature: the 'contact' orebodies, so-called because they occur along the contact; and 'outlying' orebodics, which are enclosed in the volcanics. The former arc tabular or lenticular bodies elongated along the strike and dip of the contact. The 'outlying' orebodies are coniform, chimney-like masses roughly elliptical in plan; with depth, their roots plunge at steep angles toward the contact. All of the orebodies are cut by a number of light-coloured granophyre and felsite porphyry dykes. These dykes-the so-called 'mine' dykes -enter the mine area from the north, curve gently southeasterly across the orebodies, and then cross the contact into the gabbro at the south end of the mine. All the dykes dip vertical to steeply east.

Jan 1, 1941

By Michael Young, Peter Allum, Mingwei Gao

"Tough economical conditions and high grade but fine-grained ore processing have forced the mining industry to look for more efficient processes. Isa Mill Technology for ultra-fine and fine grinding is one such process employed at several mining operations in Australia including Mount Isa Mines Limited in Australia. Mount Isa Mines is a business unit of MIM Holdings Limited. MIM is an Australian-based international mining and mineral processing company with around 8000 employees worldwide. Major products include copper, gold, zinc-lead-silver, coal and technology sales.The Isa Mill is a horizontal stirred mill with sizes up to 3 m3 chamber net volume and 1 120 kW installed motor. It was jointly invented by Mount Isa Mines of Australia and Netzsch Feinmahltecknik GmbH of Germany for ultra-fine and fine grinding duties in the minerals industry. Isa Mill operations started in 1994 at the Mount Isa Mines Leadzinc Concentrator and then at MIM’s McArthur River Mine in 1995. These Isa Mills have been used to liberate sphalerite and galena at Mount Isa and silica at McArthur River by grinding to less than 7 micron.This paper discusses the Isa Mill Technology and reports on the metallurgical performance of the Isa Mills at Mount Isa Mines, including work done over the last 9 years to improve mill design, process efficiency and maintenance, which has resulted in the current state-of-the-art Isa Mill Technology.INTRODUCTIONThe current leadzinc deposits at Mount Isa Mines (George Fisher, Hilton and Isa) have an average grade of 10.5% zinc, 7.2% lead and 165g/t silver. Fine grinding, in particular in the zinc retreatment circuit requiring a milled product P80 of 7 micron, is essential to treat the ores from the Mount Isa Mines deposits. Every one micron size reduction in the zinc retreatment circuit below a P80 of 10 micron improves the overall plant zinc recovery by 1%, resulting in an increase in revenue of about 1 million dollars per annum."

Jan 1, 2002