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"In 1989, improved milling and recoveries resulted in a record production of 7 722 200 Ib Nb2P5 at the Niobec Mine. At the beginning of 1990, proven and probable reserves stood at 11 952 000 tons grading 0.65% Nb205. This year, the world steel market has slowed and as a result, niobium consumption is down. Consequently, production at the mine dropped 14% for the second quarter.IntroductionThe Niobec Mine is located approximately nine miles northwest of Chicoutimi, Quebec, (Fig. I). After ten years of production, the Niobec Mine is the only operating niobium mine in North America and the second largest producer of niobium in the world after Brazil.The Niobec Mine is a joint venture held equally by Teck Corporation and Carnbior. Teck Corporation operates the mine while Cambior is responsible for marketing and selling the niobium pentoxide concentrate (Nb2P5).The deposit was discovered in 1964 following an airborne radiometric survey in search of uranium. However, mining of the deposit did not begin until 1976. The initial production capacity of 1500 tons per day was increased several times to the present capacity of 2450 tons . The deposit is considered as an ample source of pyrochlore concentrate for at least 15 years at the present production rate.Niobium, also known as columbium, is a greyish-white metal used primarily as an alloy in various steels and other metals. The use of niobium in alloys heightens tensile strength and improves corrosion resistance while at the same time reducing the weight of the alloy. Niobium is also used in the fabrication of steel for the aerospace, automobile, and oil and gas pipeline industries. Although substitutes for niobium exist, their use often results in diminished performance and net cost increases."

Jan 1, 1990

By Robert B. Parsons

"Next month will mark the anniversary of the release of an important federal study on a mineral policy for Canada. The study, entitled ""Mineral Policy-A Discussion Paper"", provides well-researched coverage of a broad range of issues that are of interest to the mining industry. Unfortunately, there is a real possibility that the discussion paper will wither and die on the vine, unless the federal and provincial governments, and the private sector, collectively ensure that some of the key considerations which are raised by the paper are acted upon.IntroductionAlmost one year ago, on March 8, 1982, Federal Mines Minister July Erola released an important study entitled ""Mineral Policy-A Discussion Paper"". The discussion paper, which presents the government's assessment of the opportunities and constraints facing the Canadian mineral industry in the 1980s, was prepared within the context o f three principal objectives-strengthening the resource base on which the industry rests, ensuring the adequacy of research activities needed to support development of the resource, and furthering the development of markets for the resource It is clear that, in today's economic climate, not even the most generous incentives would turn the industry around: what is needed is a sound base for future development, when this is possible. In this regard, the discussion paper is an excellent stepping stone, in that it reviews a wide range o f fundamental policy issues which touch on all facets o f the mining industry."

Jan 1, 1983

By V. Polotski

This paper describes a platform for autonomous operations in open pit mining environments. A typical operation consists of: (1) Initial locomotion toward a remote worksite; (2) Pattern navigation within the worksite; (3) Worksite manipulations and (4) Return locomotion to the start location. The platform includes precise localization module based upon the fusion of odometry, inertial and GPS measurements. The guidance module starts from a set of way points specified on a GPSreferenced map and plans and executes the mission. A typical mission includes specified manipulative tasks along the navigation path. During motion execution the on-board system continuously verifies that the path is free of obstacles and that the hardware is not overloaded. Momentary losses of external positioning measurements does not adversely affect the performance, owing to the redundancy in position and heading estimation. A rehearsal phase follows planning and allows the supervisor to examine the kinematic behavior of the platform during motion, thus reducing the need for continuous monitoring during execution and providing protection against potential losses of communication.

May 1, 2003

The following guidelines have been recommended by the Diamond Exploration Best Practices Committee established by the Canadian Institute of Mining, Metallurgy and Petroleum. These guidelines are applicable to public companies and their consultants reporting diamond exploration results. In respect of these guidelines, Diamond Exploration Results are results derived from the initial activities undertaken to investigate a diamond bearing prospect or deposit, to generate tonnage, grade and value estimates that cannot be classified as a Mineral Resource or Mineral Reserve. They do not address the earlier stage reporting of geophysical, geochemical or kimberlite indicator mineral results. Public reports of Diamond Exploration Results relating to mineralization not classified as Mineral Resource or Mineral Reserve must address the confidence limits of the result and contain sufficient information to allow a considered and balanced judgement of the significance of the results. The objective of these guidelines is to assist public companies and consultants in making appropriate disclosure of diamond exploration results by reporting in a manner which is: ??Uniform within the diamond exploration industry; ??Consistent with reporting from other industry sectors; ??Comprehensive; ??Unambiguous. The guidelines are not prescriptive. Materiality is the overriding principle that determines the information that should be disclosed. However, where a company or consultant deviates from the guidelines, the disclosure or technical report should state the extent to which the guidelines have not been followed, and the reasons for the deviation. The guidelines do not in any way replace jurisdictional reporting requirements (For example, the requirement for Canadian reporting issuers to comply with Canadian Securities Administrators National Instrument 43-101 by having technical disclosure endorsed by a Qualified Person as defined in that legislation).

May 1, 2003

By Otto Engel

"A multipurpose program for a hand-held programmable TJ-59 calculator and PC-100C printer facilitates the evaluation of various mineral processing tests and the calculation of mass and metal balances. Its application is demonstrated by some example problems. Detailed user instructions are given for each application.IntroductionThe program listed in Appendix I is written for a programmable Texas Instruments TI-591 PC-100C calculator I printer combination. The program is applicable for the evaluation of:1) screen analyses;2) flotation test s; and3) mass and metal balances.Each application is demonstrated by an example problem and corresponding detailed user instructions. The ""measured"" data in the examples are fictitious and do not represent a real operation.The steps in using the program are the same for each of the three types of application, viz.:1. Enter the number of product fractions and press ""A"".2. Enter the measured weights (0) of each fraction and press ""RIS"" each time. After the last fraction has been entered, the printer automatical1y displays the total weight.3. Press ""B"" to calculate the weight distribution (Y). Once ""B"" is pressed, the printer automatically displays the weight distribution of all fractions.4. If the accumulated weight distribution (EV) is also needed, press ""RIS"". The printer now displays these data. This step is optional and may be bypassed.5. Press ""2nd A"" to prepare for entering of the measured metal assay (M).6. Enter the measured metal assays of each fraction and press ""RIS"" each time. If analytical data exist for more than one metal, each data set has to be entered separately in one sequence.7. Press ""C"" to determine the ""calculated"" head assay (MA) of all fractions.8. Press ""RIS"" to calculate the metal distribution (R). Once ""RI S"" is pressed, the printer automatically displays the metal distribution of all fractions. This operation is optinal and may be bypassed if desired.9. Again press ""RIS"" to obtain the accumulated metal distribution (ER). This operation is optional and may be bypassed.10. Press ""D"" to calculate the gangue distribution in the concentrate (W). One ""D"" is pressed, the printer automatically displays the data for all fractions. This operation is optional and may be bypassed.11. Press ""RIS"" to obtain the accumulated gangue distribution (EW). This operation is optional and ma y be bypassed.12. For more than one metal, press ""E"" to clear the memory for storing the assays of the next. Then press ""2nd A"" and start entering the assays of the next metal as described previously (6 to 11). Steps 5 to 12 may be repeated as many times as desired."

Jan 1, 1982

"Since all gold mills must sooner or later be cleaned up for permanent shutdown it was felt that a record of what was done at one mill might be of some help to those who will have to do the same job in the future,In cleaning up the mill of Delnite Mines Limited, I had an advantage that most mill superintendents will not have in that I started up the mill and was there until it was shut down, It was also known for two years approximately when the shutdown would be and for a year almost the exact time. This, of course, made careful planning possible and enabled me to get advance information that wouldn't have been available had the shutdown come unexpectedly,Early in 1964 calculation of ore reserves and the known number of working places available indicated that the mine would run out of ore sometime in August or September but not later than October, The time of course would vary with the number of competent miners that could be retained until the shutdown. Since the mining method used exclusively on the ore then remaining was cut and fill, it was known that once mining operations ceased it would require at most two days to crush and grind the last of the ore.In March 1 964 I took samples of the concrete floor under the precipitation presses, in the flux room and furnace room of the refinery and from the assays obtained proved that there would be no profit in breaking up the concrete to recover the gold from it, Samples taken from the top half inch of the concrete floors assayed less than 0, 10 oz per ton,"

Jan 1, 1966

"This paper discusses the use of risk assessment and risk management techniques within the Australian underground coal mining industry, within the context of geotechnical risk. The industry works within a pro-active, “enabling” legislative framework, where companies and management apply a range of risk assessment tools as part of their everyday management processes. Different geotechnical risk factors and approaches are reviewed, together with application examples – ranging from mine planning and design, operations, and accident investigations.A particularly powerful resource in each of the above stages of geotechnical management is the RISKGATE system. RISKGATE is an assembled “body of knowledge” structured under different topics across the Australian coal industry, of which three topic areas address rock mechanics issues for both the underground and surface mining sector. This paper will provide an overview of RISKGATE in the context of risk-based rock mechanics applications in underground coal mining."

Jan 1, 2015

By M. E. Stutt, R. H. Rehder

"The mining industry is taking advantage of the increased performance resulting from the use of variable speed A C drives for large motors. This technology provides increased efficiency under the variable speed and torque requirements of such drives as mine hoists, conveyors, and air moving equipment. The technology does introduce voltage spikes on the voltage wave form that stress the insulation system to a greater degree than would occur with a constant voltage source. These voltage spikes must be considered in the design of the insulation system used for these motors.BackgroundHistorically the insulation systems for large AC motors were designed to withstand with reasonable life the voltage stresses of a 60 Hz constant sinusoidal voltage. One of the design tests is a voltage endurance test that requires the application of a 60 Hz voltage from conductor to ground equal to four to five times normal and establishing a time to failure. These higher than normal voltages accelerate the normal aging process by causing extensive partial discharge activity (corona) within the insulation system and the time to failure is a relative indication of insulation life.In addition to the voltage endurance test at 60 Hz, the individual coils are subjected to a surge voltage test to establish the withstand capability of the turn to turn insulation under switching surge conditions. The surge voltage is a fast rise time, 0.2 microsecond to crest value, voltage spike that can be caused by a circuit breaker or contactor closing operation. These voltage spikes can have a crest value of greater than 3.5 times the normal line to ground crest voltage of the normal 60 Hz power supply. The standard withstand test value is thus 3.5 times normal line to ground voltage. Because the voltage surges or spikes occur mainly during start and stop switching conditions, voltage endurance under these conditions has not been a major factor in insulation system design."

Jan 1, 1995

By Alain Tshilombo, Vijay Reddy, Chowdary Meenavilli, Kelvin Buban, Cory Kosinski, Sriraj Meenavilli, Siddhartha Tirumalaraju

The use of artificial intelligence (AI) for process optimization is expected to play an increasingly important role in the future of the mining industry. The objective of AI is to develop a data driven soft (virtual) sensor using historical data that can estimate unmeasurable characteristics of the process and provide appropriate recommendations during operation to optimize the process through continuous learning. The application of AI to a hydrometallurgical process was evaluated by Sherritt Technologies in coordination with NTWIST. Historical operating data obtained from the Ambatovy facility’s High Pressure Acid Leach (HPAL) circuit was used to develop models to predict autoclave discharge parameters based on operating conditions and ore mineralogy. The prediction models were developed in such a way to also allow the user to simulate and test different operating conditions. A second set of models (AI model) were developed based on the prediction models, economic data and operating constraints for a given process unit to identify optimal reagent and steam dosages across the HPAL circuit. The development of these models was significantly complex due to the dynamic and interactive nature of the HPAL process. Despite the complexity of the models, the models were able to predict, with accuracy, the relationship between ore composition, leach autoclaves retention time, acid addition and steam addition with metal extractions as well as levels of impurities in the autoclave discharge slurry. The study showed that AI has the potential to improve the overall operation of a facility through providing tools to assist with training, troubleshooting and process optimization. INTRODUCTION The Ambatovy project, located in Madagascar, is one of the world’s largest nickel and cobalt mining and processing operation, with a design capacity of 60.000 tonnes of nickel and 5,600 tonnes of cobalt per year (Collins et al., 2016). Commissioning and start-up of the Ambatovy mine and plant facilities were completed in 2012, with acid first introduced to the ore leach in March 2012. Commercial production (defined as 70% of design capacity) was achieved in January 2014 and the production level required to achieve financial completion (90% of design capacity for 90 days) was achieved in March 2015 (Valle et al., 2016). Figure 1 shows a simplified flowsheet of the hydrometallurgical pressure acid leach (PAL) process employed by Ambatovy.

Jan 1, 2019

By A. Navarra, Norman Toro, T. Marín, Fernando Ayala

The quantitative techniques to evaluate the enhancement of a particular unit operation should consider the corresponding changes to the adjacent unit operations. For example, the expansion of off gas handling capacity should consider the corresponding changes in converter cycle times, matte grade, and other operational parameters, that can provide the optimal system-wide benefit. In general, the upgrading of smelter equipment is risky due to the size of capital investment, as well as any unforeseen impacts on rest of the operations. However, this risk can be mitigated by applying the principles of Front End Loading (FEL) in the formulation of multiphase re-engineering projects. The initial phases of engineering are relatively inexpensive, and determine whether or not to pursue the subsequent phases that are comparatively more expensive. Each phase of engineering depends on increasingly detailed descriptions regarding the critical phenomena that can effect design decisions; the increasing levels of detail may result from numerical simulations, as well as laboratory and plant trials. The quantitative framework should be sufficiently flexible to accommodate these increasing levels of detail, regardless of the particular phenomena, so that it may evolve throughout the project. The current article describes the combined usage of mass balancing, thermochemistry and multiphysics, in the development of discrete event simulation (DES) and finite differences (FD). The incorporation of finite differences into a DES framework depends on adaptive time-stepping, to determine threshold-crossing times, e.g. when the matte temperature surpasses a critical level that necessitates the addition of cold charge. The hybridization of DES and FD is appropriate for multiphase smelter development projects, as it supports semi-continuous material flows, operational policies and scheduling, as well as unexpected events and trends, in increasing levels of detail. This type of framework will support the installation and tuning of modern control systems, including state-of-the art sensors and machine learning algorithms.

Jan 1, 2019

By D. C. Martin, P. M. Hawley, C. P. Acott

"In bedded deposits such as coal or sedimentary iron, economic limits of mineable reserves are clearly defined by the footwall of the seams or ore-bearing units. Where open pits are developed in dipping strata, a long, high footwall slope may result. In many cases, unbenched slopes excavated along the base of the lowest mineable seam are operationally simple, economically desirable and geotechnicalty practical, although a variety of failure mechanisms may develop. This paper examines the engineering geology and rock mechanics parameters of importance in the design of footwall slopes. Possible failure mechanisms and stability analysis methods are described. Design considerations for benched and unbenched slopes are discussed with prime consideration given to development of long high stopes without benches or with a minimum number of benches. IntroductionIn bedded deposits, the ultimate depth and economic viability of an open pit in dipping strata may be controlled by the design of the footwall slope. The stability and, hence, design of footwall slopes is strongly influenced by the engineering geology and rock mechanics parameters of the slope forming materials. A clear understanding of the structural geology, engineering geology and tectonic history of the deposit is essential to assess the behaviour of the slope. This is particularly important for long high, unbenched footwall slopes such as shown in Photo I.A rational footwall slope design requires identification and assessment of all possible slope failure mechanisms with respect to the proposed slope geometry. Stability analyses of each potential failure mechanism are used to identify the main controls on slope stability and to develop appropriate slope design criteria. The optimum slope design is based on the most economic and geotechnically practical slope geometry with due consideration of operational constraints and of the possible advantages of specific remedial measures."

Jan 1, 1986

By K. M. Tait, M. M. McDonald

"An overview of the status of the development and application of Integrated Gasification Combined Cycle (IOCC) power generation is presented. Current projects in North America, Europe and Japan are described, together with the status of plans to apply the technology in Canada. A brief review of the technology is presented, including promising coproduction cycles and hybrid gasification fluid bed processes. The ability of the process to be modified for CO2 to be extracted for enhanced oil recovery or disposal is addressed. The environmental impact of IGCC technology is compared to those of other power generation technologies IntroductionDefinition and HistoryIntegrated Gasification Combined Cycle (IGCC) technology is a concept which has been around for about 50 years but has been generating increasing interest in the last 10 to 15 years. This paper focusses on coal as the feedstock for gasification. Other feedstocks used in gasification systems have included oil, biomass, tires and petroleum coke. IGCC technology integrates coal gasification with generation of electricity by means of a combined cycle system which fires the produced gas in the gas turbine. Figure 1 shows the basic components of an IGCC system which are the gasifier, the gas cleanup system and sulphur recovery plant, the gas turbine/generator set, the heat recovery steam generator (HRSG) and the steam turbine/generator set. The benefits of an IGCC system over a conventional Rankine Cycle pulverized coal (RCPC) fired system for the generation of electricity from coal are that the IGCC system has potential to have higher efficiency and lower emissions of NO., SO and CO2 per unit of power produced than the corresponding RCPC system."

Jan 1, 1994

By Vic Briccardi

Energy Management Challenges The Holistic Standard to Energy Management Energy Management Information System (EMIS) "Best Practices?: Energy Management Maturity Curve De Beers Canada Profile & Mine Locations Significant ROI Driven by Real-Time Energy Visibility Mining Energy KPI?s Summary: What Does EMIS Deliver? Q&A Session

May 1, 2013

By E. Roman E.

A novel anode slime purification process was developed and tested at pilot scale in the Chuquicamata Refinery. The process consists of three main stages: First, an atmospheric alkaline leaching at 90°C, under controlled pH and ORP operation parameters where metalloid impurities are preferentially removed from the anode slimes with high efficiency. In a second stage, alkaline washing of the mud leached with addition of reducing agent, with the intention of reducing the silver of the AgCl to metallic silver releasing the chloride, and finally, copper and other remaining impurities are leached out in mild conditions (60°C, one hour in sulphuric acid). In a side process Se, Te, and Sb are recovery with high efficiency from the alkaline liquor as chemical grade products. The global balance shows a high mass loss yielding a final product with high precious metal and low impurities content showing advantages in both a technical and economic point of view with a clear environmental sustainability. This treatment allows either the direct sale of the purified anode slimes or its pyrometallurgical treatment to obtain metal doré without emissions of Se, Sb and As. Chemical mechanisms for this novel process are also described.

Jan 1, 2007

By Mike Anderson

The annual budget for the repair and maintenance of equipment at Syncrude Canada Ltd is in excess of 450 million dollars. Of this amount, a significant portion can be attributed to the loss of material on various pieces of equipment throughout the operation. In order to effectively battle the different wear and corrosion mechanisms that lead to material loss, it is important to understand how materials behave in the environments in which they are used. Through the work carried out at Syncrude, and work conducted with various external collaborators, significant improvements in both equipment reliability and productivity have been achieved. This paper will review some recent field trails where materials research has demonstrated the potential for significant improvements in equipment run life and reduced maintenance costs. These field trails will demonstrate the need for understanding the interaction between various damage mechanisms and the materials used in different services. The paper will also discuss current areas of focus along with future directions for further work.

May 1, 2003

"The gravimetric dust sampler is one of the tools now available to the industrial hygienists for determining the worker 's exposure to the numerous types of particulate matter that may be present in the workplace. The paper ' reviews the different sampling trains that can be used for the two major criteria for respirable dust and some of the sources of error in this dust assessment technique.IntroductionIt may be stated simply that the measurement of airborne dust in the working environment is done for one or two reasons: namely, for engineering control purposes and! or to evaluate the potential for toxicological insult arising from the inhalation of dust particles.This paper reviews the progress made in the development of dust-assessing instruments, particularly the gravimetric types designed to meet British and U.S. dust criteria , and discusses the limitations in their use for this purpose."

Jan 1, 1981

By Neil Schofield

"The estimation of recoverable ore reserves for feasibility in precious metal deposits such as Pine Creek must account not only f or the extreme variability of the ore grade but also for the complexity of the geology. Compatible models f or both must be adopted. Further, very selective mining demands reserve estimates be based on small selection units whose individual grades cannot be estimated reliably from the exploration drilling data.Multigaussian kriging is one method based on a multivariate normal model for estimating recoverable reserves under such conditions. In this paper, a non-mathematical description of the multigaussian model is presented together with its application to the Pine Creek Gold Deposit. The results, when compared to the first year of production, are encouraging for the model but not without surprises.Together, Part 1 and Part 2 of this study combine a detailed and geologically conditioned variogram analysis with an appropriate estimation method for a highly variable low-grade gold deposit. This and other studies of gold deposits familiar to the author show convincingly both that while the appropriate geostatistical skills and techniques are necessary to tackle the question of reserves, equally important but often discounted is the need for an appropriate and compatible geological model. IntroductionThe Pine Creek gold mineralization is associated with saddle reefs, and quartz and quartz- sulphide veining within the Enterprise Anti cline. The anticlinal structure is complex and, prior to mining, the mineralization was considered to be mainly strata controlled. Grades vary up to 160 grams in l .5rn core samples with coefficients of variation in excess of three.The estimation of the recoverable reserves for such a depo sit must account for both the geological complexity and the extreme variability of the gold grade.Part 1 of this work presented the geological model for the deposit and summary statistics 0 f the gold data. A detailed structural and variogram analysis considered both gold grades and the normal score (or gaussian transform) of these gold grades for different composite sizes."

Jan 1, 1988

By F. P. Hassani, J. F. Boily, A. M. O. Mohamed, M. Hossein

The optimal geochemical parameters required to form ellringite in a lime-remediated site have been investigated with the use of thermodynamic modelling. The speciation of sulphate and 10 metals analyzed in samples of a mine tailing from northern Quebec was calculated with a computer model. The model also includes calcium, which would result from the addition of lime to the system. Two speciation calculations were done. The first one is a hypothetical speciation before the onset of precipitation and was used to devise the stability fields of minerals susceptible of forming in high pHs. The stability fields were determined by building activity ratio diagrams with sulphate, aluminum and calcium species concentrations for pHs ranging from 4 to 14. The investigation was carried out for a 25°C solution with an ionic strength less than 0.12. Thermodynamics predict that an optimal stability field for ettringite in the mine tailing samples containing 10-3 mol/L SO4-2,10-2 mol/L of AI(OH)4 requires at least 10-2mol/L of Ca+2 and a pH larger than 11.6. The sulphate contents of the mine tailing samples, however, limit the precipitation of ettringite and monosulphate could be an end-precipitate. The second speciation is in equilibrium with precipitates and provides information on the speciation of the residual metals. If ellringite could be precipitated as a stable form, it could serve as a sorptive agent for residual metals, and, due to its binding properties, consolidate tailings.

Jan 1, 1995

By Stephen Mcgibbon, Tim Twomey

"Abstract - The High-grade Zone (HGZ) was discovered 5000 ft (1520 m) below surface in the hangingwall of the existing orebody, 46 years after the Red Lake mine first went into production. The very rich ore of the HGZ is characterized by a remarkably abundant distribution of visible native gold. The location of this discovery challenged conventional wisdom at the time and its genesis has yet to be fully understood. Textural observations of ore within carbonate veins as well as crosscutting relationships suggest peak-metamorphic emplacement for at least some of the gold. Post-lamprophyre dike remobilization of gold is locally observed in the HGZ. Structure and dilatancy were the key elements for localizing ore at the Red Lake mine. Ore occurs where a fault trend intersected folded ultramafic volcanic rock that created a semi-permeable cap-rock to ore fluids ascending the "feeder" structure. This was enhanced by strong competency contrasts between the eastern ultramafic rocks, felsic volcanic rocks west of the HGZ, and the mafic volcanic host to ore - an exceptional environment for the development of protracted dilatant fluid pathways for gold deposition.Development in the HGZ began in February 2000 and reached commercial production on January 1, 2001 at a capital cost of US $53 million. December 2001 reserves are 1.9 million short tons (1.73 Mt) at an average cut and diluted grade of 2.05 ounces per ton gold (70.5 g/t) containing 3.8 million ounces of gold. The extremely rich ore presented a unique challenge in grade estimation for the Geology Department at the mine. The historic cutting factor was replaced by a statistical method as more data were collected from mining and mill reconciliation. The mine produced 503 000 ounces of gold in 2001. Exploration at the mine is targeting HGZ-type ore formation within basalts associated with the intersections of fluid pathways and folded ultramafic rocks, as well as other targets."

Jan 1, 2001

By Yun-Soo Lee, Su-Hyeon Kim, Hyoung-Wook Kim, Joon-Hyeon Cha

A7075 aluminum alloys have high strengths but poor corrosion resistance. In order to improve the corrosion resistance, a clad sheet is suggested, that is the A7075 alloy sheet bonded to A1XXX or A6XXX aluminum alloy sheets which are surface layers with good corrosion resistance. Mechanical properties of the clad sheets are determined by the combination of the component layer sheets, and thermomechanical treatment should be precisely designed when the strengthening methods of the core and the surface alloys are quite different. In the present study, three-layered A6022/A7075/A6022 clad sheets were fabricated by roll bonding process. Simplified processes incorporating a twin roll casting were also suggested in order to reduce the processing cost. Several temper methods composed of rolling, annealing, solution treatment, and aging were suggested in order to optimize the mechanical properties of the sheets. The strengths of the clad sheets were compared with the bare A7075 and bare A6022 sheets.

Jan 1, 2015