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By Robert B. Parsons

"The 1994 Quebec Budget included a significant overhaul of the mining duties sys-tem in that province: broadening the base and lowering the rate, all in the name of “ensuring the integrity of the taxation system"" and ""enabling the State to collect fair compensation "". The reforms hit hardest on the small, lightly-capitalized producer, by repealing the basic annual exemption, limiting the refund for losses, and significantly reducing the investment and processing allowances. There is some relief provided in the form of faster depreciation rates and a lower nominal tax rate, but the thrust of the overhaul is clear -higher taxes on the mining sector.IntroductionAlthough Quebec's mining tax regime represents under 10J0 of the province's revenue base, and was significantly reformed in 1979 and 1985, the May 13, 1994, provincial budget introduced further significant changes to the Mining Duties Act, The hope (on the part of the province) is to reduce the provincial ""subsidy"" for mining by $20 mil· lion per year by 1996."

Jan 1, 1995

By John P. Hunt

Early disseminated copper mineralization at Quebrada Blanca, Chile, accompanied 38 million year old quartz monzonite stocks and dikes. Early mineralization was followed by hydrothermal mineralization, mineralized breccias, and post-mineral faulting. After supergene leaching and enrichment, Quebrada Blanca was buried under late Tertiary gravels, and then partially re- exposed in Quaternary time. Based on work to date the orebody appears to contain more than one hundred million tons of plus one percent secondarily enriched copper ore, overlying several hundred million tons of protore averaging more than 0.5% copper. A source of industrial water appears to have been located. Pilot scale metallurgical tests, mine planning, and feasibility studies are in progress.

Jan 1, 1981

By J. C. Marquardt L., J. A. Bratt, J. P. Hunt

The Quebrada Blanca copper/molybdenum prospect lies on a dissected plateau in the high Andes of Northern Chile. The Superior Oil-Falconbridge Group began exploration of the Property in 1977 under a joint venture foreign investment agreement with the Chilean government. Quebrada Blanca is a relatively high grade secondarily enriched porphry copper deposit. Primary mineralization occurred 38 million years ago and accompanied quartz monzonite intrusive. Early disseminated Primary mineralization was followed by hydrothermal mineralization, mineralized breccia, and post-mineral faulting. After supergene enrichment Quebrada Blanca was buried under late Tertiary gravels and then partially re-exposed in Quaternary time. During the past five years, a successful exploration program has developed an open-pit mining reserve, provided samples for bulk metallurgical testing, and located more than adequate supplies of water for future operations. The main orebody is amenable to conventional metallurgical treatment and contains more than 400 Mt (441 million st) of recoverable open-pit ore at about a 1:1 overall stripping ratio. The average millhead grade during the first six years of operations will exceed 1.5% Cu, plus recoverable molybdenum values. Several hundred million tons of additional reserves are available in the surrounding districts

Jan 1, 1984

By V. F. Hollister

The Queen Charlotte gold deposit (also known as the Specogna, Babe, or Cinola) was discovered in late 1970 by Efrem Specogna and Johnny Trico. They were prospecting along the trace of the Sandspit fault, and they sampled jarositic material that included veins from the fault zone. Their assays included some good gold values. They located the Babe Claims in 1971 and optioned them to Kennco Explorations Ltd. Kennco conducted stream sediment and soil geochem studies, geological mapping and drilling of 55.2 m (181 ft) in two drill holes. Kennco withdrew from the property, and by 1977, Cominco, Placer Development, Silver Standard, and Quintana Minerals had each successively worked on the deposit. Consolidated Cinola Mines bought the claims in 1977 and completed exploration of the deposit ultimately in a joint venture arrangement with Energy Reserves. Energy Reserves entered in late 1979, and by 1983, a total of 200 surface and 12 underground drill holes had been completed, totaling 28 600 m (93,832 ft). In addition, a 461.9 m (1515 ft) adit was driven in the ore body. Reserves published by Cinola aggregate 34 Mt (37 million st) of 1.7 g (0.060 oz) Au per tonne. All industry geologists working in the area agree that the Queen Charlotte gold is an epithermal gold deposit in porous volcaniclastic and clastic rocks that is genetically related to a Miocene-Pliocene rhyolite plug. The geologic description here follows the oral presentation made by G. G. Richards, J. S. Christie, and M. R. Wolfhard at a 1976 CIM meeting. Additional comments by the late C. S. Ney of Kennco Explorations are included with the Richards, Christie, and Wolfhard data to complete the geologic set- ting. The attached reprint by Champigny and Sinclair (1 980) provides additional data on the deposit. The Queen Charlotte (Babe, Specogna, or Cinola) gold deposit is located on Graham Island in the northern Charlotte Islands, at the fault boundary of the Skidegate plateau and the Charlotte lowlands. The Sandspit fault marks the physiographic boundary, and it is intruded by rhyolite porphyry at the deposit. Because displaced geochem anomalies, drain- age patterns, and topography suggest dextral and east side down movement for the fault, exposed east block rocks are younger than rocks west of the fault. The east block, which included the ore deposit, is a lowland largely masked by unconsolidated Pleistocene and Recent clastic rocks. Rocks west of the rhyolite plug, on the Skidegate plateau, are Cretaceous carbonaceous and calcareous shale unconformably overlain by a thin veneer of rhyolite tuff. The deposit is about 100 m (328 ft) above sea level. GEOLOGIC SETTING At the ore deposit, the Sandspit fault is a complex structure. However, lithologies on either side of the fault-controlled rhyolite porphyry plug are distinct. West of the rhyolite, the upper member of the Cretaceous Haida formation shale is the most common rock type. The member is composed of dark grey to black, poorly consolidated, and thinly bedded carbonaceous and calcareous shale. The sequence is silicified to an argillite or a hornfels near the rhyolite. West of the rhyolite porphyry plug, but not importantly involved in the mineralization, is a thin masking cover of rhyolite tuff. The tuff unconformably succeeds the cretaceous shale, but it is largely eroded in the mine area. East of the fault-controlled rhyolite porphyry plug is a thick section of conglomerate and sandstone of the Miocene- Pliocene Skonun formation. The ore body occurs within the coarse clastics, the rhyolite intrusive as the western boundary. Ore is entirely contained within the clastics. Original permeability of the clastic rocks was a major control for ore deposition and alteration, and for that reason, the Skonun formation is described in greater detail. The Skonun formation clastics unconformably overlie Haida shale. The Skonun is at least 300 m (984 ft) thick in the mine area, where it trends northerly and dips easterly 15º to 25º. The sequence is about 62 percent conglomerate, 3 1 percent coarse arkosic sandstone, and 7 percent interbedded siltstone and sandstone. Contacts between adjacent beds are generally sharp. Stratigraphic correlations between drill

Jan 1, 1985

By J. Moore Samuel

THE prospective change in ore receipts at the Copper Queen reduction works necessitated a careful study of conditions to determine the most economical method of smelting. The first step, calculating the known, probable, and possible results, showed the economy of a unimetallurgical flow sheet f which the three pyrometallurgical stages would be roasting, reverberatory smelting, and converting. The past and future ore receipts (not including converter flux) are as follows: AVERAGE MONTHLY FUTURE MONTHLY RECEIPTS, 1918 RECEIPTS TONS PER PER CENT. OF TONS PER PER CENT. OF MONTH TOTAL RECEIPTS MONTH TOTAL RECEIPTS Ore 84,553 82.3 43,000 44.0 Gravity concentrates 16,375 15.9 25,500 26.0 Flotation concentrates 1,883 1.8 29,400 30.0 Total 102,811 100.0 97,900 100.0 Of the 102,811 tons per month received in 1918, only 28,945, or 28 per cent., was treated in the roasters and an average f 14.1 roasters out of 20 were in operation; the remaining ore was treated in the blast furnaces. The change to "all reverb." practice, therefore, called for considerable additional roaster capacity, which could be obtained either by building additional units, or by remodelling the present units so as to give increased unit capacity. In view of the progress in roasting practice since the construction of the Copper Queen roaster plant and the heavy investment in that roaster plant, the second plan seemed to be the more desirable. The Copper Queen roaster plant consisted of twenty six-hearth, McDougall roasters, 18 ft. in diameter, equipped with cast-iron arms that originally were water cooled but now are air cooled. They have no top dry hearth and the feed is discharged through the top arch, near its periphery, by plunger feeders from two bins at opposite sides of the roaster.

Jan 7, 1921

By José Cáceres

Mine To Mill? ? Carlisle(1954) ?The economic of a fund resource with particular reference to mining?. ? Steine(1978) ?Coarser grind may mean lower metal recovery but higher profit?. ? Metalica (1999) ?Mine Plant Integrated Planning?. ? JK (2002) Mine to Mill Strategic Planning ? Camus, Kelebek (2002) ?Management of Mineral Resources: Creating Value in the Mining Business?. ? Caceres (2003) ?Integrating Milling Parameters in the Mining Planning?

May 1, 2006

By David Smith, Bernie Martin

The Queens Bored Tunnels consist of 11,000 feet of 19'-6" inside diameter tunnels mined through rock, mixed face and dense glacial till, constructed with bolted gasketed one pass reinforced concrete liner. The tunnels are to be excavated with a pressurized face TBM, either EPB or slurry. The construction of the tunnels will require ground stabilization in the mixed face area, instrumentation and monitoring of railway infrastructure, underpinning of bridges, relocation and protection of utilities, demolition of some industrial buildings, construction of open-cut approach tunnels and emergency exits and vent plants. The purpose of this paper is to describe the scope of work, the suggested methodology and the proposed construction schedule.

Jan 1, 2005

By Bernie W. Martin, Jesus Schabib

The East Side Access (ESA) Project in New York will be the largest tunneling project ever undertaken by a US railroad. The objective of the ESA project is to connect the Long Island Rail Road (LIRR) Main Line and Port Washington Line in Queens to Grand Central Terminal in Manhattan. The Project is divided into two distinctive segments: Manhattan and Queens. The Queens segment is subdivided into two major components; cut and cover tunnel construction and bored tunnels. The bored tunnels in Queens consist of five tunnels driven from a launch shaft and traverse a railway storage yard, Sunnyside Yard and terminate under the multitrack mainlines of Amtrak and LIRR at portals in the heart of Harold Interlocking where1200 trains pass every day. The soil consists of remnants of glacial till moraines and of outwash and till deposits of inter layered gravel and fines, with the occasional boulders and cobbles and with a high ground water table. It is anticipated that a Pressurized Face Machine, either slurry or Earth Pressure Balance equipped with roller disks to mine the boulders encountered as well as the mixed face, will be used to mine the tunnels. One pass reinforced concrete gasket bolted liner will be used. The cut and cover construction consists of an approximately 21.3 m (70 feet) deep excavation supported by slurry walls and jet grout columns. The slurry walls, in combination with overlapping jet grouted columns, are installed to top of rock forming a closed bathtub to control external groundwater drawdown. Maintaining the groundwater level near its original elevation is of paramount importance in order to prevent undesirable settlements and migration of groundwater that could be contaminated. Mitigation measures to prevent the migration of nearby plums are contemplated for all types of tunneling and excavation work in this site of the ESA project.

Jan 1, 2001

The Queensland Magnesia Project is based on a unique cryptocrystalline nodular magnesite orebody which required an innovative approach to process design in order to economically exploit the characteristics of the ore and produce a marketable range of high quality refractory magnesias for a declining world market. High quality natural refractory magnesia must have an MgO content in excess of 95 per cent with a very strictly controlled content and ratio of residual impurities such as calcium, silica and iron. The natural products compete with magnesias derived by chemical extraction from sea water or brines which exhibit very high purity but often lack other characteristics which are of value to refractory brick makers. Since start up in late-1991 QMAG has achieved a remarkable market penetration for both its deadburned and electrofused products with sales for the 1993/94 financial year representing 92 per cent of deadburned capacity and 138 per cent of original electrofused capacity respectively, all at a time when the world steel industry has been in recession.

Jan 1, 1995

This paper will examine the prospects for Queensland's non-fuel mineral industries as we approach the 21st century. The opportunity for growth is unprecedented. Exploitation of recent discoveries, proposals and developments in downstream processing are predicted to contribute to a doubling of the State's mineral exports to around $10 billion by the year 2000. In 1995 - 96 the value of Queensland's mineral production was $6 billion, comprising $1892 million metallic minerals, $127 million non-metallic minerals and $4 025 million total fuel minerals. For many years Queensland has been among the world's major producers of copper, silver, lead, zinc, bauxite and mineral sands. Recently Queensland has become an important producer of magnesia. Queensland's ability to compete results from its location close to rapidly developing Asian markets, the diversity of its major minerals and an increasing ability to add value to the resources base using competitively priced energy. Northwest Queensland is one of the richest base metal provinces on earth following the recent discovery of five world-class orebodies. Of these deposits, Osborne (copper-gold) has commenced production and Cannington (silver-lead-zinc) and Ernest Henry (copper-gold) are scheduled to be developed by 1997. Century Zinc Limited and the Queensland Government are negotiating with native title claimants on the development of Century (zinc-lead-silver). Expansion is in progress at the Mount Isa copper mine (renamed the Enterprise) and copper smelter and a high analysis fertiliser project may be developed based on Phosphate Hill. Korea Zinc Company Limited has reached agreement to construct and operate a 350 000 Mtpa zinc smelter/refinery near Townsville. There are future expansion prospects for the vertically integrated major industrial mineral operations based on Weipa bauxite and Kunwarara magnesite. Upgrading of the Boyne Island aluminium smelter will require a doubling of alumina consumption. Downstream processing options for Kunwarara magnesite are being investigated and are expected to lead to increases in production and the manufacture of a range of value-added products. At the Yabulu refinery near Townsville, nickel and cobalt production using imported ore is to be increased and a commercial cobalt plant is to be built. Additional opportunities for further processing and manufacturing are associated with proposed new mines at Ely (bauxite), Skardon River (kaolin) and Goondicum (ilmenite). Recently discovered resources of zeolite and perlite also offer exciting development possibilities. Other manufacturing opportunities such as glass and ceramics based on local and plentiful clay and silica sand could replace imports. Silica sand at Cape Flattery is currently exported and production is expected to double.

Jan 1, 1997

By Ring R. J, Waters D. J, Vautier F. E, Fulton E. J

Laboratory leach tests have been carried out by the Australian Atomic Energy Commission to compare the effectiveness of Caro's acid (permonosulphuric acid) as an alternative oxidant to pyrolusite in the leaching of uranium ores. Results demonstrated that Caro's acid reduced acid consumption in leaching and the lime required for neutralisation of tailings liquor. The uranium extraction was unaffected by choice of oxidant.Following this study, Interox Chemicals Pty Ltd arranged a plant trial using Caro's acid at the Nabarlek uranium mill of Queensland Mines Ltd. The trial confirmed that significant savings in acid and lime usage can be achieved under plant conditions.Plant operations also demonstrated that Caro's acid has a number of significant operating advantages over pyrolusite.Queensland Mines Ltd have recently decided to convert their leaching process from pyrolusite to Caro's acid. The new system is expected to be fully operational by mid 1983.

Jan 1, 1983

By M C. Evans

"Mine decommissioning is the final phase in a mining project. Planning for decommissioning must commence for a proposed mine even before the government approves it. Queensland mining approvals require proponents to commit to completion (or closure) criteria defining successful rehabilitation. Queensland mining project statutory environmental authorities must also specify how progressive rehabilitation is to occur throughout the mining project. Final landforms with graded banks together with creek and run-off diversions are often required and constructed early in the life of a mining project. At closure, mining projects must demonstrate that future medium-term risks are not significant, or failing this, a residual risk financial payment must be made to the state. CSIRO climate change projections indicate that Queensland is likely to become warmer this century with less rainfall in parts and with extreme rainfall events likely to occur more frequently. This project was undertaken to?determine: if current rehabilitation planning tools assist in determining the environmental risks from mining closure not adequately addressing climate change if these risks are addressed by current rehabilitation outcomes.The north-west Queensland mining region and the central Queensland coalfields were represented in this project by five study sites. Local data sets for temperature, rainfall and rainfall intensity were produced using conservative greenhouse gas emission scenarios representing likely future atmospheres, and using the SimCLIM climate model, Evaporation data sets were also derived from available climate parameters. These projected climate variables supported equations and models used in Queensland to determine mining project rehabilitation completion criteria. Storm intensities and return intervals were directly applied to assess the likelihood of failure of engineered structures such as stormwater diversions and banks. Plant cover change determined by an existing growth model together with rainfall intensity and changes in the R and C factors of the universal soil loss equation (USLE) erosion model enabled estimates of long-term erosion rates. Flood estimates were undertaken using regional rated catchments.The study found that stormwater diversions and banks on recontoured rehabilitated landforms, if constructed to currently accepted completion criteria, would likely fail within 30 years and with the likelihood of failure steadily increasing thereafter. The change in likelihood of failure was able to be estimated and could be applied to the determination of residual environmental risk for approval of a surrender application involving rehabilitation. The USLE model showed that long-term erosion rates increased as a consequence of climate change from north to south across the Queensland mining precincts. Because the growth model did not consider carbon dioxide fertilisation affects, results would likely be worse-case.Likely climate change outcomes have consequential residual environmental risks of mining project rehabilitation failure. This increased risk may result in increased payments to the state from mining projects where high consequences exist. The liability to the state and risk to the environment can be avoided if today’s completion criteria address tomorrow’s climate change impacts.CITATION:Evans, M C, 2014. Queensland mines should consider climate change impacts for decommissioning, in Proceedings Life-of-Mine 2014, pp 535–562 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

The Yabulu refinery of Queensland Nickel Pty Ltd located near Townsville now imports more than three million wet tonnes per year of nickel laterite ore from New Caledonia and Indonesia, making it the largest importer of any commodity in Australia. The project has illustrated that importing untreated bulk ore and re-exporting high value products makes good economic sense for the company and the nation. The economics of this exercise have been considerably enhanced in the past year by changing the project's principal product from nickel oxide sinter to refined high purity nickel metal. It is one of the few operations in the world where nickel ore is transformed to nickel metal at a single site. Several novel technological processes were developed at Yabulu and incorporated into the refinery to allow this product transition to occur. By utilising internally developed technology the new processes were installed at a capital cost of less than $10 million. It is unique for a large nickel producer to completely change the quality of its entire product range many years after the plant was constructed and considerable attention to marketing the new products has been required.

Jan 1, 1995

The Yabulu refinery of Queensland Nickel Pty Lld near Townsville now imports more than three million wet tonnes per year of nickel laterite ore from New Caledonia and Indonesia, making it the largest importer of any commodity in Australia. The project has illustrated that importing untreated bulk ore and re-exporting high value products makes good economic sense for the company and the nation.The economics of this exercise were considerably enhanced in 1994 by changing the project's principal product from nickel-oxide sinter to refined high-purity nickel metal. It is one of the few operations in the world where nickel ore is transformed to nickel metal at a single site.Several novel technological processes were developed at Yabulu and incorporated into the refinery to allow this product transition to occur. By utilising internally developed technology the new processes were installed at a capital cost of less than $10 million. It is unique for a large nickel producer to change completely the quality of its entire product range many years after the plant was constructed and considerable attention to marketing the new products has been required.The changes have meant that the project is no longer limited to selling lower-value oxide sinter to a relatively small number of large stainless steel mills. In the past year sales of the new high purity nickel metal products have expanded to include a broad range of international customers in the special alloy, foundry and chemical industries.

Jan 1, 1995

By B Lyne

In 1990, the Queensland mining industry had come to the conclusion that new safety and health legislation based on risk identification and control was required if the mining industry was to be effectively and efficiently regulated. In particular stakeholders in the coal mining industry had arrived at this opinion after the industry had suffered a number of major underground explosions over the 14-year period between 1972 and 1986. Also by 1990, a general consensus had emerged across both the coal and metalliferous mining sectors that mining industry was over regulated and, more to the point this over regulation did not encourage industry to identify and address the underlying causes that had led to a cycle of major mining accidents in the state. The prevailing opinion was that the prescriptive legislation left the ownership of risk management with the regulator and not with the mine operator. This paper discusses the background to the development of the Queensland Coal Mining Safety and Health Act 1999 and the Mining and Quarrying Safety and Health Act 1999 and the progress made in improving safety and health since the statutes came into force on the 16 March 2001. The paper discusses the issues that had to be addressed during the development of the legislation including the interaction with other legislation based on based on risk management principles that either overly or interface with the mining legislation. The effect the underground explosion at Moura No 2 in 1994 had on the final content of the new legislation is also considered. Health is often the neglected twin of safety and health legislation and the paper previews the health surveillance system being proposed in Queensland to ensure that health of mine and quarry workers is afforded the same priority as their safety. By increasing the structured management of occupational health problems in our mines there is an opportunity to make significant improvements in mine safety In conclusion the paper reviews the results to date since the introduction of the new mining safety and health legislation in Queensland on the 16 March 2001. Progress has been made and more is yet to be achieved

Jan 1, 2003

By M Clay, J Dunlop

Thermal and metallurgical coal mining in Queensland has resulted in mines which contain voids due to open cut mining. While there are several proposals for greenfield coalmines or expansions to existing operations, many existing open cut coalmines are reaching maturity and most will leave one or more residual voids in place. The rehabilitation of mine voids is challenging. Water held in voids will evaporate over time leaving solutes to concentrate. This is likely to lead to poor water quality with limited practical use. The most basic practices to rehabilitate voids have historically involved stabilising the high and low walls, bunding to provide flood protection, and preventing public access. Regulatory reforms for mine rehabilitation were introduced in Queensland as part of the Mineral and Energy Resources (Financial Provisioning) Act 2018, and aimed to strengthen progressive rehabilitation planning, limit risks to the environment and improve outcomes for local and regional communities. Under the reforms, the goal for rehabilitation of voids is to achieve a safe, stable, and non-polluting landform, which can sustain a post-mining land use (PMLU). The reforms also introduced a requirement to describe rehabilitation of mined land in Progressive Rehabilitation and Closure (PRC) plans, replacing the description of such plans in Environmental Authorities (EAs). The reforms are not retrospective and recognise historic approvals for voids, meaning established voids will remain in the landscape as non-use management areas (NUMAs). The objectives of this study were to outline historic void rehabilitation planning practices, describe water quality limitations of Queensland mine voids and identify possible opportunities for improved planning

Aug 2, 2023

By Wagner da Silva Lima

Um Sistema Piloto de alimentação de biomassa foi instalado em paralelo ao sistema de alimentação de coque em uma caldeira leito fluidizado circulante movida a coque de petróleo na Unidade Fabril da Votorantim Metais em Niquelandia, GO. Quatro experimentos foram realizados utilizando os alimentadores de coque (limitados a capacidade de mistura da pá-carregadeira) e o sistema piloto instalado que tem capacidade de 30 m3/h de cavaco de eucalipto. A substituição energética chegou a 19%, bem acima dos 10% determinados pelo fabricante utilizando o sistema atual de alimentação de combustível na caldeira. O potencial de redução de custo do vapor varia de 4 a 7%.

Aug 17, 2017

By Bert Taylor

"The Mining concessions of Quemont Mining Corporation, Limited, are located at 48°16'N latitude, 79°00'W longitude, in Rouyn township, northwestern Quebec. Six hundred and forty acres in area, they lie directly north of, and contiguous to, the Horne mine of Noranda Mines Limited. The north arm of Osisko Lake covers a large area of the southern part of the property. The orebodies lie below the Jake with one body extending through to the bedrock surface.The property was staked in 1922, and was originally known as the Murray Claims. The group attracted interest from numerous exploration companies because of the proximity of the Noranda orebodies.The United Verde Extension Company, of Arizona, optioned the claims in 1926. They sank a shaft to a depth of 235 feet, at a short distance from the Noranda boundary. From a level established at a depth of 215 feet they completed 3000 feet of exploratory driving from which 6000 feet of diamond drilling was done. Only a small body of siliceous gold ore was found before they dropped their ·option.In 1928, The Mining Corporation of Canada purchased a 90 per cent interest in the property. An operating company, later named Quemont Mining Corporation, was formed. An electrical survey was carried out on a portion of the property, followed by deepening of the shaft to 922 feet. Levels were established at 500 and 900 feet, and 4,800 feet of driving and more than 3000 feet of diamond drilling were carried out from them.Geological knowledge at that time recognized that a major break, the Horne Creek fault, lay not far inside the south boundary. Striking north 80 degrees east, the fault dipped south at 85 degrees. The rock on the north side of the fault was massive rhyolite; to the south, meta-diabase and a little rhyolite. A left-handed movement was indicated by a 600-foot offset on a north striking diabase dyke. The small body of siliceous gold ore, referred to previously, was confined to the 215 level."

Jan 1, 1949

By J. S. Scott

"The Quemont property comprises 640 acres lying directly north of and adjoining the Noranda (Horne) mine. During 1926 to 1928, United Verde Extension Mining Corporation sank a shaft 235 feet and did 3,000 feet of development work on the 215-foot level. Between 1929 and 1930, Quemonr Mining Corporation deepened the shaft to 926 feet, and did further lateral work and drilling on the 500- and 900-foot levels. This work was confined to an area close to the south boundary and met with little encouragement.Following a period of idleness a magnetic survey was made in the winter of 1944, followed in the summer of the same year by some 6,000 feet of drilling. The first successful hole was drilled in February, 1945, from the ice of Osisko lake.To the time of writing, 131,000 feet of drilling, surface and underground,have indicated a large tonnage of gold-silver-copper-zinc ore, and although some knowledge of the geology and structure is emerging, it is too early to draw definite conclusions. The following brief description deals only with those structural features that are reasonably well indicated."

Jan 1, 1954

By L. Yin, R. B. Haber, N. Sobh, D. A. Tortorelli, R. W. Hyland Jr.

"We optimize continuous quench process parameters to produce a desired precipitate distribution in aluminum alloy extrudates. To perform this task, an optimization problem is defined and solved using a standard nonlinear programming algorithm. Ingredients of this algorithm include a cost function, constraint functions and their sensitivities with respect to the process parameters. These functions are dependent on the temperature and precipitate size which are obtained by balancing energy to determine the temperature distribution and by using a reaction-rate theory to determine a discrete precipitate particle size distribution. Both the temperature and the precipitate models are solved via the finite element method. Since we use a discrete particle size model, there are as many as 105 degrees-of-freedom per finite element node. After we compute the temperature and precipitate size distributions, we must also compute their sensitivities. This seemingly intractable computational task is resolved by using an element-by-element discontinuous Galerkin finite element formulation and a direct differentiation sensitivity analysis which allows us to perform all of the computations on a PC.1 IntroductionThis work addresses the need for an integrated design capability that links microstructure evolution to the process parameters. It is motivated by the manufacture of lightweight aluminum-alloy extrusions for use in automotive structures. Aluminum alloys offer obvious benefits, however, care must be taken to manufacture favorable microstructures that ensure acceptable structural performance. For example, the manufacturing process for 6000-series components involves hot extrusion of cast aluminum billets followed by either an air or water quench process. The bill~t's initial grain structure is dramatically altered during extrusion by massive mechanical deformations and recrystallization processes. The microstructure continues to evolve during the quench, as complex chemical processes determine the formation of precipitates. The control of the precipit'ate size distribution is vital. Indeed, large precipitates located on grain boundaries serve as crack initiation sites which adversely effect structural crash· worthiness."

Jan 1, 2000