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By B. W. Steele

"Dofasco began operations in 1912 as a steel foundry located in Hamilton, Ontario. Today, Dofasco is a fully integrated mill that manufactures hot rolled, cold rolled, galvanized and tinplate steels. Customers include the automotive, construction, tubular, manufacturing, appliance, packaging and steel ser-vice centre industries. Raw steel production and purchased semi-finished steel processed in1994 was 3.5 million net tonnes. Dofasco employs 7300 people at its Hamilton facility.Environmental management at Dofasco is guided by its environment policy and associated commitments. This paper discusses Dofasco’s responsibility for its products as it relates to these commitments. Dofasco is com-mitted to:n the principles of sustainable development that require that activities be conducted in a manner that provides for the present without compromising the ability of future generations to meet their needs. These principles will be integrated into product design, manufacturing and business planning;n managing renewable and non-renewable resources through the responsible application of reduce, reuse, and recycle principles;n minimizing any potential impact of its operations and products on the environment, employees, customers and the community;n continuous improvement of the effectiveness and integrity of our environmental management systems;n developing understanding among all employees about their responsibilities, and assigning the necessary authority; andn meeting the standards set by relevant legislation and international agreements through participation with governments and the diligent application of economically feasible and scientifically sound methods and technologies."

Jan 1, 1996

By W. G. Robinson

"MINING is one of Canada's most important industries and exploration is the life-blood of this dynamic and exciting business. The health and growth of the mining industry of tomorrow depends on the effort and thought that go into exploration today. The Members of the Geology Division of the C.I.M. are directly concerned with exploration, and it is fitting that this Division should periodically sponsor reviews of the thoughts and practices of the exploration com-munity. Accordingly, we have invited seven leading authorities to contribute papers dealing with specialized aspects of this field.Exploration is a science, or art if you will, that is constantly changing in keeping with our expanding knowledge of geology and technology. It started with the old-time prospectors who searched the wilds for exposures of ore, and made finds that developed into some of our most important mining camps. As more discoveries were made, they were able to relate certain types of deposits with particular geological conditions, laying the foundation for modern concepts of economic geology. The mapping by the early field parties lacked detail and usually served to outline the ""greenstone"" areas considered favourable for prospecting. More de-tailed studies through the years by government and company geologists led to new thoughts on the origin, emplacement and geological control of orebodies. The continuing diversity of opinion on these subjects indicates a need for further research, but each year sees an increase in our reserves of factual information."

Jan 1, 1967

By Warwick D. Bullen

Gold mining in the Yellowknife area of the Northwest Territories started long before the concept of sustainability entered the academic literature and by the time the term enjoyed widespread public acceptance, the Yellowknife gold mining industry was in its sunset years. Nevertheless, the city of Yellowknife will long outlive the gold mines that it was founded on, demonstrating that not only can mining build sustainable communities, but that sustainable mining as a concept is an entirely valid precept. To this effect, the authors examine the complex economic and social aspects of the gold mining industry in the Yellowknife area over the last 70 years.

May 1, 2004

By K. J. Mintz

Conveyor belts installed in an underground mine can be a potential source of a major fire, thus the need for fife-retardant belting. A Canadian Standard, CAN/CSA-M422-M87, incorporating a small-scale flame test, a drum-friction test, a flame propagation test and an electrical surface-resistance test, has been developed to meet the varied needs of the mining industry. It is recommended that mines use Types A and B belting described in that Standard, because they will have passed the large-scale flame propagation test, rather than Type C, which does not require that test. Belting that has been approved by the U.S.A. Mine Safety and Health Administration (MSHA) may be much less fire-retardant than any Canadian approved belting.

Jan 1, 1992

By Karl J. C. Harries

"6.1. INTRODUCTIONThis chapter comments on some of the more common types of agreements related to property examination and acquisition, other than the farm-in/joint venture agreement or common undertaking, which is dealt with in the next two chapters. Many of the comments made in Part IV of Chapter 4 apply equally to any such agreement. In addition, many of the comments in Chapter 8 and the examples in Volume II are most certainly relevant to many other types of agreement.6.2. RIGHTS OF FIRST REFUSAL1A right of first refusal is a right that obligates an owner to offer his property, or an interest therein, to the holder of the first right if the owner intends to sell or otherwise dispose of it. It may be triggered either by the owner wishing to offer his property for sale or by receipt of a bona fide offer to purchase his interest from an “outside” third party. The mechanics and procedures to implement a first right should be set out clearly in the agreement, and their basics are the same, whether the first right is a stand-alone document or is part of an acquisition agreement.2Rights of first refusal are common in agreements to permit some control over the disposition of an interest and there they can be a valuable provision. However, some explorationists feel that they are also a good stand-alone agreement to have while a property is being evaluated to decide whether or not it is worth optioning. The reasoning is that such an arrangement will tie up the property to allow a quick look and, if the property looks interesting, the balance of the term of the first right will give an ample exclusive period of time to negotiate with the owner and settle an acquisition agreement. In addition, the explorationist is protected by the first right if the owner decides to negotiate a deal with another party."

Jan 1, 2003

By D. Van Tonder

ABSTRACT The comparative economics of ion exchange and direct precipitation have been analyzed by developing indicative CAPEX/OPEX models for typical alkaline leach uranium circuits. An agitated tank ore leach application is considered, comparing resin-in-pulp and direct precipitation as recovery options. Capital and operating cost estimates are derived from rates and factors used in recent studies and projects. The analysis showed the main economic drivers to be the ore grade and resin loading. The resin loading is impacted by the prevalence of competing ions, especially chloride. At resin-in-pulp solution chloride concentrations below 3 g/L and uranium grade below 640 g/t U3O8, resin-in-pulp is more economical, whereas at chloride concentrations above 3 g/L, direct precipitation is more economical.

Jan 1, 2012

By P. C. Lighthall, D. W. Zandee, W. Shukin

"IntroductionThis chapter deals with the on land disposal and storage of fine tailing in slurry form behind dams. Other types of tailing, such as coarse dry cobbs from magnetic separation of iron ores and other dry materials, have special problems and are not addressed in this paper. The disposal of mine waste is not included, except as such materials may be of value in the construction activities related to tailing disposal.In earlier North American mining, mines were smaller and frequently disposed of their tailing by direct discharge into neighbouring streams or bodies of water. Where that was not practical or not permitted, the solids were collected in tailing ponds and only the effluent liquids were released or decanted. The dams used for these early impoundments were fragile structures and failures were common. With the advent of large, low-grade open pit mines, and increasing awareness of environmental and safety considerations, recently established mines have carefully-designed tailing disposal systems, with wellconstructed dams and attention given to protection of the environment. Older mines are being improved or at least being examined critically with a view to upgrading as necessary to meet the new standards.Modern tailing disposal systems are highly variable and unique to each mine. Tailing pond selection and design is dependent on available topography as also is the design of transport and water reclaim systems. Suitable sites that are at higher elevations than the mills or distant from them may require that the tailings be pumped. Dams, either earth or rock structures built of the most convenient and economic material, are usually a suitable mix of local borrow, mine waste and coarse tailings. The most economic structures are those built mostly of coarse tailing."

Jan 1, 1989

By I. C. Edwards, D. C. Smith

THE milling plant of Bicroft Uranium Mines Limited at Ban-croft, Ontario, was one of the first in Canada to employ ion excl1ange for the selecti1•e recovery of uranium from acid leach liquors. The ion ex-change circuit started operating early in November, 1956, and by June 1 I959, had handled more than two million tons of pregnant solution containing I,830,000 pounds of U3Os. Each column had been saturated and eluted about 430 times. The ion exchange columns are the conventional fixed bed type. Uranium is eluted from the resin with a sodium chloride-sulphuric acid solution and is precipitated continuous-ly with magnesia. After filtering and drying, the precipitate, or "yellow cake," is packaged in drums for shipment to the refinery.

Jan 1, 1962

By James A. Robertson

"This paper is the result of a continuing investigation begun in 1953 by government geologists and mining companies. Previous work is reviewed and the development of several stratigraphic nomenclatures and correlation schemes is traced, culminating with the interim report of the Federal-Provincial Committee on Huronian Stratigraphy formed in 1966.The stratigraphy, structure and correlation of the Huronian rocks of the Blind River area and the region between Sault Ste. Marie and Sudbury are reviewed. The area is underlain by three Precambrian units: (1) the Archean greenstones and granites, (2) the Huronian sedimentary and volcanic rocks and (3) the post-Huronian intrusive rocks. The Huronian rocks, largely quartzite and conglomerate with greywackes, argillites and carbonates, were laid down in shallow water transgressing over the eroded Archean basement. Thickness and facies changes indicate a northwesterly source, northerly overlap and deposition controlled by basement topography. Polymictic conglomerates, occurring at least at three horizons, represent tillites and are associated with varvites with dropped clasts. These are best developed in the Gowganda formation, which varies from a continental glacial environment in the north to a marine glacial environment in the southeast.There were at least three phases of post-Huronian igneous activity, probably related to several periods or phases of late Precambrian deformation and metamorphism: (1) sills of Nipissing diabase and rather younger diabase dikes; (2) the Cutler Granite and Croker Island Complex; and (3) dikes of Keweenawan olivine diabase.Copper mineralization is associated with the Nipissing diabase. The uranium ores are found in pyritic quartz-pebble conglomerate near the Huronian Archean unconformity, particularly in ancient valleys; they are considered to be placer deposits modified by later events. Uranium production from the Blind River camp to the end of 1966 was 128,160,096 pounds U308 valued at $1,203,840,848 derived from 56,077,179 tons of ore grading 0.11 per cent U308.Within the Blind River and adjacent areas, future discoveries will probably be the result of costly systematic deep-drilling programs accompanied by detailed geologic studies of the type carried out by oil companies and probably computer-oriented."

Jan 1, 1969

By Cesar H. Oboni

The development of specific risk-based methodologies to guide and prioritize clearing decisions in countries contaminated by Unexploded Ordnance and Land Mines (generically defined as Explosive Remnants of War: ERW) either at country-wide scale or road-network-scale was used in an unexpected way when a large mining company asked Riskope (www.riskope.com) to develop a multi-modal transportation network risk assessment plan, which included ocean going vessels, ports, wharves, railroad, trucking and other modes of transportation. What had been a first-in-the-world attempt in the humanitarian landmine clearing industry turned out to be extremely useful and equally innovative in the extractive corporate world. Instead of a country contaminated by man-made hazards such as Explosive Remnants of War (ERW) we were now dealing with a very complex multi-modal transportation system afflicted by all sorts of potential hazards from quakes to climate change, sabotage to labour strikes, and vulnerable infrastructures to potential energy crises. Interestingly enough the method developed to deal with ERW risk based clearing was also capable of solving the transportation risk evaluation problem, after necessary customization. This paper shows how ?out of the box? thinking and industry cross dissemination can bring significant evolution and a competitive edge even to unexpected areas of the world-wide mining industry. The results of the logistic system risk assessment shed new light on the management of the system, changed the way insurance coverage was purchased, and led to significant potential cost reductions in a period of global recession.

May 1, 2010

By Fathi Habashi

Extraction by organic solvents is a chemical process in which metal species in the aqueous phase react with an organic reagent to form an organometallic com- plex, thus, the metal species leave the aqueous phase and enter the organic phase from which it can be stripped back in the aqueous phase to obtain a pure and a concentrated solution. The metal in the organic phase is not bound to carbon atoms as in organometallic compounds but to oxygen, nitrogen, sulphur, or hydrogen by a co-ordination (dative) bond (Habashi, 1999).Solvent extraction was used for the first time in hydrometallurgy in connec- tion with the special and urgent materials requirements of nuclear energy during World War II. A plant was constructed in the United States for the preparation of high-purity uranyl nitrate solution. In this plant, the yellow cake (a high-grade sodium or ammonium uranate) was dis- solved in HNO,, and uranium was selec- tively extracted by ether then stripped by water to give a concentrated solution of pure uranyl nitrate. This was gradually followed by developing methods for other high-priced metals such as plutonium, thorium, niobium, tantalum, zirconium, hafnium, boron, beryllium, and molybde num. The second step took place in the 1960s when solvent extraction was applied for the first time to extract a rela- tively cheap metal-copper. At present, solvent extraction technology is wide- spread, well accepted, and highly efficient. Solvent extraction had its origin in the discovery, by Christian Friedrich Bucholz (1770-1818) in 1805, that uranyl

Sep 1, 1999

By E. Tulcanaza

Mining companies normally establish exploration and research programs originated with actions in embryonic stage. At their early stages of development, these exploration and technological activities are subject to uncertainties that need, first, to be resolved, deciphered or, at least, mitigated for information reporting; and later, for valuation reporting. Under these circumstances, these exploration activities follow a sequence of development phases that range from exploration work to the profile, conceptual, and finally to basic engineering phases and construction. For information reporting, the International Template for Reporting of Exploration Results, Mineral Resources and Mineral Reserves integrates the minimum standards being adopted by the relevant professional bodies in Australia, Canada, South Africa, Chile, USA, UK, Ireland, and other European countries which set up the Committee for Mineral Reserves International Reporting Standards (CRIRSCO, www.crirsco.com). These standards are based on the progressive collection of relevant information to reduce present and future uncertainties over time under a context of transparency, materiality, and technical competence. For valuation reporting several procedures have been disclosed and applied. However, in the last decades financial instruments such as real options, decision analysis, and games theory have developed into a niche of great potential for mine valuation applications. The objective of this paper is to provide a summary of the information reporting standards prepared by the Chilean National Commission for the Qualification of Competent Persons in Mineral Resources and Mineral Reserves and show a procedure and an application of real options to the valuation of the sequential development phases of a mine asset from the exploration stage through up to full development.

Jan 1, 2007

By H. Yoshida, H. Hatta, T. Suzuki

"The effect of the copper and magnesium contents and quenching rate during quenching on the age hardening behavior of 2000 series aluminum alloys was investigated. For the higher copper-containing specimens as conventional alloys, like AA2024, precipitation of the stable phases increased as the quenching rate decreased under the as-quenched conditions. The maximum hardness after the artificial aging of air cooled(AC) specimens was much lower than that of the water quenched(WQ)specimens. On the other hand, for the lower copper-containing specimens, coarse precipitation did not increase even in the case of the AC. The age hardening behaviors of the WQ and AC were very similar such that the maximum hardness and aging rate were almost the same. Many parts of the fine precipitates that increased the hardness were thought to be the GPB zone or fine S’ phase for the WQ and relatively coarse S’ phase for the AC. From the calculated CCT(continuous cooling transformation)diagrams, the lower copper-containing specimens could maintain the copper and magnesium in the solid solution state during the AC, so they could be quenched at a rather slower quenching rate like the AC.INTRODUCTIONThe 2000 series aluminum alloys, containing copper and magnesium as the major chemical components, are some of the well-known heat treatable aluminum alloys. These alloys have a high quenching sensitivity, thus the age hardening ability of these alloys decreases with as low quenching rate. To prevent the decrease of the age hardening ability, quenching is done by a method such as water quenching, which is not very efficient in an industrial situation, because the method requires such large equipment. For these alloys, reducing the quenching sensitivity helps them to be produced in a rather convenient way. For example, 6000 series alloys such as A6063 have low quenching sensitivity, thus they could be quenched by only air cooling just after extrusion and they do not need water quenching. Based on these reasons, investigations of these alloys with high copper and magnesium contents have been conducted in the past to find a way to lower the quenching sensitivity by adding transition elements such as manganese, chromium and zirconium (Kanno, Suzuki, & Itoh, 1986; Suzuki & Itoh, 1986; Kanno, Sakuma, Muromachi, & Watanabe, 1988). However, very few studies have focused on the quenching sensitivity of the lower copper and magnesium containing alloys because of their usage for structural components with high strength, and most of the past studies have used only the fast quenching method like water quenching. On the other hand, from our recent results, there is a possibility to lower the quenching sensitivity of 2000 series alloys with lower alloying elements. In this paper, the effect of the copper and magnesium contents with lower alloying elements and quenching rate, especially in case of slower quenching rate than conventional quenching method, on the age hardening behavior of the 2000 series alloys is investigated by the hardness measurement, structure observation and thermal analysis."

Jan 1, 2018

By G. M. Ritcey, K. E. Haque

"Laboratory-scale sulphuric acid leach tests were conducted on Elliot Lake and Rabbit Lake ores in the presence of various oxidants, namely: Fe2(SO4)3, CI2, H2O2, NaClO3, MnO2, H2SO5, HNO3, Oxon e, K2Cr2O7, KMnO4, O3 and O2. Uranium extraction is significantly accelerated when an oxidant is present in the leach slurry. Uranium extraction of 96-99% can be achieved by maintaining the oxidation potential of the leach slurry in the range of400 to 500 m V (S.H.E.). A rough cost comparison of all the oxidant s indicates that the use of Fe2(SO4)3, 02, O3, C12, HNO3 or MnO2 is far less expensive than NaClO3 and the uranium extraction rates are similar to or better than with NaCIO3. For uranium extraction, it is concluded that gaseous oxygen (i.e., air or oxygen) would be the most effective and economical oxidant for the 24- to 36-hour leach of Elliot Lake ore; whereas for the 8- to I2-hour leach of Rabbit Lake ore, a strong chemical oxidant (e.g. NaCIO3, H202, 03, K2Cr2O7, H2SO5 or HNO3) would be a logical choice.IntroductionThe common practice for the treatment of uranium o res is leaching with sulphuric acid or with a carbonate-bicarbonate mixture. Generally, the latter process is ad opted when an excess (> 18%) of acid-consuming components (e.g., carbonate) is present in the ore. Irrespective of the nature of the leachant, the addition of an oxidant to the leach mixture is necessary to obtain a high uranium extraction.The maximum extraction of uranium can only take place when all the uranium is in the highest oxidation state (i.e.,U +6-uranic ion) . Because a certain percentage of uranium present in the ore is invariably in the lower oxidation state (i.e.,U+4-uranous ion) , the addition of an oxidant to the leach slurry is necessary to oxidize uranous ion to the uranic state."

Jan 1, 1982

By R. M. Giegerich

"This paper begins with a brief history of Madawaska Mines, a brief description of the geology, mining methods and equipment, and the historical development of 7/8-in. tapered drilling equipment. It then outlines the performance characteristics and inherent problems of the traditional 12-degree, tapered connection, blade-type insert bits. Service-free (Unipass) button-type insert bits are presented as a possible solution to these problems. The paper concludes with an analysis of button bit performance to date.Brief History of Madawaska MinesMadawaska Mines Limited, near Bancroft, Ontario, is in Faraday Township, Hastings County, approximately 100 miles northeast of Toronto and 100 miles west of Ottawa.The mine re-opened in 1976committed to 1,500 tons per day to provide approximately 600,000 pounds of yellowcake (U3O8) per year to A.G.I.P. (an Italian government agency) under the joint ownership of Federal Resources Corporation, Salt Lake City (51%), and Consolidated Canadian Faraday Limited (49%). At present, the mine is producing approximately 2 pounds per ton (.1% U3O8) at the rate of 60,000 pounds per month. The mine employs about 400 employees.Brief Description of Geology, Mining Methods and EquipmentGeologyThe Grenville metasediments of the mine area are chiefly paragneiss, amphobolite and some carbonate (marble) rocks, which were intruded by a basic rock, altered to a metagabbrometadiorite. These formations are generally concordant, striking east to northeast and dipping 45 to 60 degrees to the south. Locally, the metagabbro is often discordant. The above group of rocks (mixed hybrid gneisses) forms the hanging wall of the south-dipping Faraday granite sheet and was intruded by nepheline syenite, syenite and granite. The ore occurs in the granite-syenite-pegmatite dykes that are probably genetically related to the Faraday granite. The ore shoots are erratically distributed within the pegmatite bodies, mainly on the hanging or footwalls but also medially. Their size varies from 50 to 350 feet in length, 5 to 40 feet in width and 50 to 200 feet in height. The ore occurs most frequently in a medium-grained granite or syenite, well hematized with 10 to 30% mafic crystals of pyroxene, amphibole and/or relics of the host rock."

Jan 1, 1982

By Peter A. Amelunxen, Richard LaDouceur, Courtney A. Young

"Many of the rare earth elements, the lanthanide series on the periodic table, are on the U.S. Department of Defense Strategic and Critical Materials list. In this regard, the U.S. Army Research Laboratory (ARL) has funded several projects at Montana Tech focusing on rare earth element recovery from natural resources. Current froth flotation operations utilize octyl hydroxamate for rare earth mineral extraction, however recovery is not ideal and flotation performance can be improved. Salicylhydroxamic acid (C7H7NO3) was identified as a novel collector due to similarities with n-octyl hydroxamate, notably the amine head group. Salicylhydroxamic acid is primarily used in the medical industry but due to the amine head group is ideally suited as a collector for rare earth mineral flotation.Parametric studies were performed for the flotation of rare earth minerals by modifying a wide range of variables. Mechanical variables of a 6L bench scale flotation cell, such as air inlet flow, rotor speed, and milling time for liberation were modified to elucidate energy input parameters for the desired minerals. Chemical parameters such as collector concentration and pH were varied to understand solution chemistry considerations of the salicylhydroxamic-rare earth mineral system. The study obtained a statistically significant experimental model for the flotation of rare earth minerals. A two stage compartmental model was also utilized for the determination of the first order flotation rate constants for each mineral. Optimized recovery of rare earth minerals was found to occur at near neutral pH ranges using salicylhydroxamic acid with maximum recoveries approaching ideal industrial standards although rare earth mineral grades were still not sufficient.INTRODUCTIONRare earth elements (REEs) are found in minerals that contain several REE which makes costeffective separation of the rare earths difficult. Significant scientific challenges have hindered mineral separation. The molecular similarity of rare earth elements results in minerals containing several REEs, such as bastnaesite [(Ce, La) CO3F]. This prevents efficient separation during concentration steps, for instance flotation, and has a direct impact on successive metallurgical processes. Consequently, concentration during flotation is of rare earth minerals (REM) as opposed to REE."

Jan 1, 2016

By Colin Harvey

The paper industry in the Pacific Northwest is a potentially large market for industrial clays. Current trends within the paper industry towards higher quality newsprint, filled and coated papers, offers an incentive for exploration in the region since the current supply of kaolin is mainly from Georgia in the southeastern U.S. Freight rates commonly exceed US$100 per tonne. The kaolin resources of the Pacific Northwest require expensive processing technologies to meet the industry specifications and it is doubtful that any large development of the local resources can be supported at the present time. Competition from high-quality regional resources of carbonates is another factor weighing against the development of local kaolin resources while there is a potential threat from shipments ofAsian and Brazilian kaolin in the early part of the 21st century.

Jan 1, 2001

By J. W. Jefferies

"Plant availability up 13%, production output up 40%, tons per employee up 15% and labor turnover down 52%. One mine manager states these were direct spin offs from the work being done to qualify for a safety award in the program known as the ""IMSRS 11 over a three-year period of time. ""Of Course"", stated this manager, ""these were in addition to an 87% reduction in our disabling injusry frequency rate.”Officially known as the International Mine Safety Rating System or the Five Star Mine Safety Rating, a new approach to mine safety is being used with enthusiasm by a significant number of mines in Canada, the U.S., Australia, Chile, Indonesia, the Philippines and South Africa. Significant results are coming into the International Loos Control Institute from over 125 mines from these countries.The program is built around a mine safety audit system that gives positive recognition to a mine at 5-step intervals along the way, (a star with each step attained). The Institute has licensed auditors in locations in Canada and the U.S. available to audit.It is believed the success of this program is the result of the premise upon which the program is based. The results being achieved are due to the concept that a modern, well-managed mine safety program maintains the basic foundation of a complete management system. When properly implemented, it reinforces those factors common to production, quality and safety. (Attitude - skill - knowledge - fitness - structure - machine - equipment - materials and processes). The IMSRS contains elements that reinforce all these factors. It uniquely treats safety as part of the ""right way"" to do the job and not just the ""safe way"" as a distinctly separate entity. Mines using this program now recognize that many of the older safety techniques were not necessarily the right way or the most efficient way to do things. It appears that this new approach to mine safety is a new avenue for the attainment of management's real goals for being in business, and at the same time achieves optimum support for the important target of safety and health for the mine worker."

Jan 1, 1983

By Antonio Segatori, Bjørn Holmedal, Kai Zhang, Trond Aukrust, Knut Marthinsen

"The visual appearance and mechanical properties of aluminium alloy extrusions are strongly dependent on the microstructure and texture of the extruded profiles, where the desired microstructure and texture may depend on the specific applications. In the present work, the evolution of deformation, as well as recrystallization textures during extrusion of AA6xxx aluminium alloys, have been experimentally and numerically investigated. Extrusion trials were performed in a laboratory extrusion set-up, which enabled immediate water-quenching of the profiles at the exit of the die, and thus the possibility to capture the deformation texture prior to post-extrusion recrystallization. The textures and their through-thickness variations were experimentally measured by the electron back-scatter diffraction technique (EBSD, and the deformation textures numerically modelled by coupling FEM flow simulations and crystal plasticity (CP) simulations. Different CP models as well as different choices of model parameters were employed and evaluated for texture predictions. With an appropriate choice of crystal plasticity model and model parameters, the deformation texture can mainly be predicted, although the accurate intensities are hard to reproduce. The corresponding recrystallization textures, either generated through spontaneous recrystallization of the extruded profiles or through post-extrusion annealing, are far more challenging to reproduce with available recrystallization models.INTRODUCTION Extrusion is a widely applied thermal-mechanical process to produce aluminium profiles. The properties of the profiles, for example mechanical, fatigue, fracture, corrosion as well surface appearance, are strongly dependent on the underlying microstructure and texture, and the requirements with respect to these aspects may vary with applications (Ralston et al., 2010; Dumoulin et al., 2012; Donati et al., 2013). Moreover, it is often a challenge to produce extrusions with a consistent and homogenous grain structure and texture along as well as through the cross section of the profiles. It is thus vital to understand and be able to predict (model) how different microstructures and textures are formed and how they evolve during and after extrusion, as basis for controlling the final appearance and properties of extruded profiles."

Jan 1, 2018

By Joseph J. Larry

In hard siliceous sandstone strata overlying coal seams, roof bolting is often the bottleneck in the coal production cycle. In the past, these strata have been drilled by pneumatically operated stopers. Although slow drilling is cumbersome and uncomfortably noisy, the stoper was the most effective drill in these harder strata. However, because of the (U.S.) Coal Mining Safety Act, which limits noise levels for operating drills, FMC Mining Equipment developed the water-through-the-drill-steel method of drilling high-compressive-strength strata. Although water-through-the-drill steel had been developed earlier, the real impact of wet drilling techniques surfaced when the dual-boom roof drilling machines were installed at the Virginia-Pocahontas Division, Keen Mountain, Virginia, in 1974. This paper covers some of the technical details of the water-through- the-drill-steel design and its application.

Jan 1, 1979