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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

By Dwayne D. Tannant

This paper presents a summary of results from a questionnaire sent to surface mines in western Canada seeking information on haul road design, construction, and maintenance. There has been a marked increase in the size of the trucks used over the last decade with some mines now using trucks with a payload capacity of 360mt. Consequentially, geometrical elements of haul roads, such as width, have been enlarged to accommodate larger trucks. Most haul roads are constructed on the basis of past experience without use of formal design procedures. With the introduction of larger haul trucks, problems related to rolling resistance, deterioration, and maintenance of the haul roads have become more important. This has lead to adoption of more rigorous design methods for roads at some mines, most notably for the oil sand mines operated by Syncrude Canada Ltd. A summary of the evolution of haul road designs implemented at Syncrude Canada Ltd. is presented.

May 1, 2001

By G. G. Bowser

Introduction Flame shots are of very infrequent occurrence in the coal mines of Nova Scotia. Probably not more than one is recorded in three months. Many shot-firers have never experienced one, and many never will. As a consequence, although all such occurrences are very carefully investigated, information concerning the cause of flame shots is somewhat meagre. In the course of the years, however, something has been learned of the practices and conditions that are responsible for them. During the past ten? years, over seventeen million shots were fired in the coal mines of Nova Scotia and only fifty-two faulty shots were reported or investigated during that time. In thirty-nine of these, flames were reported; in five, sparks only; and in eight, smoke only. In eight of these occurrences, unburned explosive was found after firing. In one of these eight, flame was seen in the back part of the hole, and an accompanying hissing sound pointed to burning explosive. In four of them, there was no evidence that gas was not ignited. All samples of explosives from these faulty shots which were submitted for analysis were found to be normal, except two, in 1937, which contained excessive moisture. These two samples were from two following shots in the same room on the same day. The initial cause of trouble with all eight shots was one or several of the following: explosives in poor condition, separation of cartridges, incorrect priming, shot hole in poor condition or not properly cleaned. In the case of sixteen or seventeen of the thirty-nine shots which flamed, data are insufficient for conclusions to be drawn as to the cause of the flame.

Jan 1, 1947

By A. S. Baillie

THE subject of taxes appears to engage our attention altogether too lightly. At least it would seem that, notwithstanding the increase in the cost of government, and its concomitant increased taxation, little constructive work is being done with a view to solving the problem of increased taxes. I believe that the inattention of the public generally to the subject of increased taxation is due largely to the fact that shareholders are not advised of the amount of taxes paid by industry. Were companies to advise their shareholders the amount of monies paid or payable out of each year's earnings for taxes in one form or another, and were such amounts compared with the amounts available for distribution to shareholders, the effect would be a general demand for more equitable taxation methods. While I am not unmindful of the burdens and inequities in taxation confronting industry generally, I believe that the mining industry in this Province does not fully appreciate the burden represented by the costs of taxation. My reason for this belief is based partly upon1the fact that no serious effort has so far been made to devise some means By which the mining industry in British Columbia might protect itself against the ever-increasing burden of taxation. In addition to this fact the widely diverse nature of mining in British Columbia makes the accumulation of comparable data a problem which, so far as I can ascertain, has never been attempted in a manner which would be authoritative. It should not be necessary to cite the effects of this burden upon any one mining company or upon any branch of the mining industry, such as coal mining, placer mining, base-metal mining, or the precious-metal mines. In my opinion, the operation of our mines by large corporations is conducive to the payment of taxes with much less protest than would be the case were the taxes being taken out of the earnings of just a few partners or a very few shareholders. We appear to be too unmindful of the taxes, paid by mining companies, of a kind that are not so prominently brought to our attention as are the taxes which are calculated upon the taxable income of the company at the end of its fiscal year. British Columbian mining companies pay many other taxes besides those which are calculated upon taxable income. Among these are school taxes, property taxes, gasoline taxes, mineral taxes, coal royalty, to say nothing of fuel-oil tax, sales tax, and excise taxes.

Jan 1, 1935

By W. J. Gibson

"This paper will provide a general assessment of the differences in construction and industrial labour relations. From this outline will come a detailed examination of labour relations in the construction industry and then specifically as related to the construction of mining projects, with emphasis on projects in isolated areas. Development of manpower forecasts, manpower availability, wage escalation formats, working rules, training and recruitment programs, and safety - as related to construction labour relations in the mining industry - are topics which will be dealt with."

Jan 1, 1972

By D. Brossman

"The virtue of spray drying is that it is a drying method, and so far the only one by which it is possible in one operation to divide a mineral concentrate into its basic primary particles.,In so doing, each particle gets the same treatment and the result is a dry concentrate more homogeneous than any other known concentrate drying process. This is particularly good for a flash furnace requiring a bone dry finely divided feed. The spray dryer also features a very short residence time and due to the very quick operation the solids are kept cool thus preventing any risk of fire or explosions on these pyrophoric materials.There are many spray dryers now in operation in the mining industry and one of the latest applications is in South Africa where a spray dryer is treating a copper-nickel platinum concentrate which is, after drying, fed toan electric arc furnace. Experience has shown that the concentrate should contain 4% moisture for the furnace, and this is achieved by drying the concentrate bone dry and then back-mixing with thickener underflow pulp to provide an extremely homogeneous feed to the smelter. As mentioned before, mixing with pulp would be more of an advantage because we would not be evaporating water which would have to be added again afterwards.One of the first spray dryers to go in was at Western Mining Corporation in Kambalda in Western Australia. (A series of slides was then shown)."

Jan 1, 1972

By F. M. Clement

British Columbia, unlike the Prairie Provinces, cannot lay claim to vast prairies. She can, however, claim many valleys, uplands and plateaus that are capable of marked agricultural development. It has been said that British Columbia is not an agricultural province. This may or may not be true, but at the present time agricultural production in this province stands second only to that of forestry. The industry has advanced from a total production of 8 millions in 1908 to a total production of 60 millions in 1924, a total increase of approximately 650 per cent in 16 years. In the last 10 years production has increased from 30 millions to 60 millions. No other industry can point to such a rapid development. In 1908 British Columbia imported 12 million dollars worth of foods compared to the 8 millions which were produced at home. In 1924 she imported 20 million dollars worth of foods compared to the 60 millions worth produced at home. In addition we exported foods to the value of approximately 10 million dollars. British Columbia is therefore self-sufficing in-so-far as values ar.e concerned except for approximately 10 millions of dollars. It is not to be expected that this province will ever grow all the coarse grains that she may require: these, along with certain meats, will always be a heavy item in the imports. We are concerned at the present time more with the value of the products than with the quantities produced: in other words, with quantities only in-so-far as ? quantities improve value.

Jan 1, 1925

By L. W. F. Mackenzie

The influence of rolling temperature and annealing on the recrystallization and texture of magnesium AZ31 has been investigated. 100x125x6 mm AZ31 plate was cast in a permanent steel mould and then homogenized at 380°C. As-cast and homogenized microstructures were then characterized, and 35x30x6 mm specimens were machined from the homogenized material. Specimens were rolled up to 40% at temperatures between 25 and 350°C; selected specimens were subsequently annealed at 400°C. Following rolling, the microstructures were compared. The influence of rolling temperature on as-rolled texture has been demonstrated, and texture evolution has been evaluated following annealing. The recrystallization behavior has also been characterized. Optical microscopy, scanning electron microscopy and electron backscattered diffraction (EBSD) were used to characterize the microstructures of the alloys. X-ray texture analysis was used to investigate the texture in as-rolled and annealed specimens.

Jan 1, 2006

By T. G. Phillips

"This paper gives an inside look at a bulk terminal and describes the preparations that must be made by a company in developing such a terminal and its position in today's traffic pattern. The following headings cover the subject material: (a) Traffic pressures, their detection and measurement, (b) position in the traffic flow -selection of site, (c) transportation connections -present and possible future routes, (d) engineering studies and costs, (e) contracts, the basic material for insured traffic, (f) financing, (g) budgetary control, (h) development of new techniques, (i) growth into new cargoes or cargo-handling methods and (j) consolidation."

Jan 1, 1968

By J. A. Dubinski

One of the greatest threats of mining in hard coal mines are underground fires, which in the past often resulted in the mining disasters. Implementation of scientific principles of fire fighting into practice contributed to a significant reduction of fire hazard in coal mines. However, despite numerous achievements of science in the fight against the underground fires, they still occur creating a potential hazard for the miners and contributing to generate significant costs of fire-fighting operations, the temporary suspension of production or loss of longwalls. This concerns both spontaneous fires and exogenous ones. A significant decrease in the number of spontaneous fires was the result of cooperation between Polish scientists with experts in the field of new methods of fire hazard prediction and selection of new fire prevention and fire hazard monitoring methods. A significant part played here researchers from the Central Mining Institute. The original method of endogenous fire risk assessment based on calorimetric tests of coal and developed mathematical model of the process of coal self-heating allow to predict the risk of spontaneous fires and select proper fire prevention measures adequate to the involved risk. The frequency of exogenous fires is in the last few years is low, but their share in the total number of fires is relatively high and constitutes about 30%. This results from the prevention activities, carried out regularly in mines which are aimed at reducing the fire hazard connected with the use of fire-resistant conveyor belts and other non-metallic materials. Further directions to reduce the hazards connected with underground fires should focus on improving the methods for monitoring hazards together with automation of fire fighting operations.

Aug 1, 2013

By Yan Yang

The Jinfeng gold mine is one of the three gold mines that Eldorado Gold has in China and it is the second largest gold mine in China. The mine is located in a relatively remote and mountainous area in the southwestern Guizhou province. The orebody is similar to the Carlin type deposit in Nevada. The mill throughput was designed to treat 3,600 tones per day. The ore comes from open pit mining and underground mining, and is fed to one-stage jaw crushing. The crushed ore is stockpiled, reclaimed and then fed to the SABC grinding circuit. After classification with hydrocylones, the ore is floated, and the resultant concentrate is oxidized biologically in a process known as BIOX®. The oxidized concentrate is then washed in a CCD circuit and finally leached with cyanide in a CIL circuit for gold extraction. Jinfeng produces about 180,000 oz of gold per year. This paper introduces operations and modifications of SABC circuit over the past three years, and then describes some technical characteristic of the SAG mill and other circuits in the processing plant. Major modifications and improvements on the SABC circuit are described in the paper, including: 1. Impacts of grinding ball and mill liner with respect to material selection, quality, hardness, manufacturing methods, and interactions between mill liner and grinding ball. 2. Effect of milling operation parameters on milling efficiency. 3. Impacts of SAG mill scats and modifications of grate size to improve mill throughput. 4. Design and construction of a pebble crushing system, and recycle the crushed scats to the SAG mill to improve mill throughput. With the above-mentioned modifications, 20% increase over the design in mill throughput has been realized over the past three years, and operating cost has been significantly reduced. However, some issues still remain, and thus process modifications and technical innovations are still needed.

Jan 1, 2012

By John Postle, Maureen Jensen, Marcel Vallee, Bernie Haystead, Dan Hora, Graham Clow

The Committee's proposed standards establish definitions and guidelines for the reporting of Exploration Information, Mineral Resources and Mineral Reserves in Canada and are identified as the "CIM Standards" and referred to as such hereafter in this document. To provide additional clarification to Qualified Persons (QPs), guidelines have been included with the respective definitions. The CIM Standards are applicable to all minerals including industrial minerals, diamonds and other gemstones. Reserve definitions for bitumen, natural gas and oil are not included in these Standards. The CIM Standards are not intended to cover mineral inventory estimates that will be reported to government agencies.

Jan 1, 2001

By Masafumi Maeda

Metal recycling and waste treatment have become common issues in various metal industries, notably, the iron and steelmaking industry and the nonferrous industry. The former tends to treat mass wastes such as municipal wastes or plastics. However, volatile compounds are condensed in dusts of their incineration processes and they should also be treated, likely by the nonferrous industry. Those "end-of-life" products contain heavy metals that might be harmful to mankind and should be handled by the non-ferrous industry. Not only revenue derived from regeneration of metals from the secondary materials but also the revenue generated from the treatment charges is a strong attraction for nonferrous industry to process secondary materials. The present study presents some statistical data of the Japanese corporations in the iron and steelmaking industry as well as the nonferrous industry on their revenues generated from processing of secondary materials. Some of the companies are now concentrating their business resources on new areas of the market. Although the quantity of waste or recyclable material is still small at present, the quantity will increase in the near future, and it is anticipated that international collaboration is required to handle the greater variety and the larger quantity of secondary materials.

Jan 1, 2004

By P. Au, R. Kearsey, D. Y. Seo, Patnaik. P. C.

Three nickel based superalloys (7.5%Cr+5%Co+2%Mo+1%Ti+5%Al and Ni balance (wt%)) containing different amounts of W and Re were produced in the single crystal (SX) condition utilizing the Bridgman casting process. First, the effect of different levels of Re, and W on chemical microsegregation were investigated by EPMA quantitative analysis, and eutectic phase fraction analysis. Second, in order to investigate the effect of these refractory elements addition on oxidation behaviour, isothermal oxidation testing of the SX nickel based superalloys was conducted at 1000°C for 277 hours under 3 ppm moisture content of air in a thermogravimetric analyzer (TGA). All three SX nickel based superalloys revealed an excellent SX solidification structure with a common primary dendrite arm spacing of -250 µm and a large fraction of ?/?' eutectic located between the secondary dendrite arms. From the average EPMA compositional results, with the exception of Ni, elements such as Cr, Co, Re, Mo, and W all tended to segregate towards the dendrite core during solidification, while Al, Ti, and Ta were present in greater quantity in the last liquid phase to solidify, which resulted in large eutectic ?/? ' phases to form within the interdendritic regions. As the nominal level of Re increased, microsegreagation of Re, W, Cr and Mo increased, indicating that Re had a much greater influence on partitioning behavior compared to W. Figure la shows the specific mass gain as a function of exposure time for each alloy. An alloy with 2wt% of W and Re (Alloy B) exhibited less weight gain compared to two other alloys with either higher content of W or Re (Alloy A and C). Microstructural and compositional analyses of oxidized samples were conducted using SEM and EDS. Figure lb shows the typical surface morphologies of the oxidized Alloys A and B. It is evident that more oxide nodules (indicated by arrows in the figure) were presented in Alloy A. It is speculated that the amount of these nodules was responsible for more mass gain in Alloy A compared to the two other alloys. From the examination of the longitudinal section of the oxidized samples as shown in Figure 2, for Alloy A, nodules actually penetrated deep into the material. For Alloy B, however, a relatively uniform and continuous oxide layer was developed and deeply attacked areas were not observed. It was also found that preferential oxidized regions were located at the area between the ?/?' eutectic phase and the dendrite arms where the concentration of refractory elements was relatively high. Therefore, it is plausible that the oxidation kinetics of these alloys is related to the extent of microsegregation.

Jan 1, 2004

By W. A. Lang

Introduction That the coal industry has entered a new phase in its development is now evident. Coal, besides being the chief source of heat and power, has become a potential raw material for many industries. Rapid progress has been made in the methods used in the mining and preparation of coal, and in the equipment for the burning of coal. Data of a fundamental nature relating to the composition of coal and to its transformations? during combustion and processing have also been revealed. Research, the key which has opened this new era, has already accomplished much, but it has only begun to show what it may and should be able to do. New developments of coal burning equipment, super-power plants, carbonizing and briquetting plants, hydrogenation and synthetic chemical processes, will undoubtedly have a marked influence in the post-war years on the economic welfare of many coal producing countries. Until comparatively recently, however, there has been in many branches of the coal industry a tendency to regard research as something abstruse and something which had little or no value to those managing such branches. But the fact that coal has suffered as a source of heat and energy through inroads of oil, natural gas, and water power, has made it plain to the industry that, if it is to maintain its present markets in this competitive world, much less increase them, the whole industry must be willing to follow the example of other industries and plan for the future.

Jan 1, 1946

By A. Pearson, Auld. F. A., S. O. Colbeck

"To minimise mine shaft maintenance over the long-term, some potash mine shaft sinking projects have required the provision of a continuous fully welded waterproof steel liner over a substantial depth to achieve zero water ingress. This brings many challenges, including the implementation of a bottom-up construction sequence incorporating extensive waterproof welding and how to ensure the integrity of the welded liner when subject to substantial temperature fluctuations that are likely to occur with a composite steel-concrete liner placed within an artificially frozen shaft excavation. This paper highlights the key challenges and discusses multiple mitigation measures including vertical shaft movement joints and a combined structural-thermal analysis approach. INTRODUCTION Whilst the application of combined steel and concrete shaft liners using a fully welded steel liner is not new and has been used in several previous projects, most notably at Lanigan (Storck, 1968 & Roesner, 1980), recently the need to provide a continuously welded steel waterproof liner for over 800 m length of shaft for a potash mine has been considered. The need for a fully continuous welded steel liner arises from the perceived benefits of providing a fully dry shaft environment to; increase the life expectancy of the shaft; reduce routine maintenance particularly combatting salt accretion and minimising wash down practices; and improve long-term ground stability by preventing salt dissolution. Whereas previous projects have employed discontinuous sections of steel liner, when a fully continuous liner is employed longitudinal shaft strains from thermal changes result in significant deformations that must be either explicitly accommodated or resisted. Note, these thermal vertical expansion forces are more than capable of lifting the shaft collar and head frame structures should they be fixed in place. Typically, shafts are designed to resist vertical forces (collar loads and self-weight) by creating mechanical interlock with the adjacent ground. In competent rock this occurs incrementally with the construction of the shaft liner, and occasional hitch/crib structures are constructed as intermediate foundations to guarantee the transfer of vertical forces at distinct horizons. Usually this means cribs are constructed at first rock head, above the station level, and at the sump, although sometimes additional cribs are formed when entering and exiting weak strata or when a change in shaft liner construction is required."

Jan 1, 2019

By Michael Nicol

A quantitative description of hydrometallurgical operations depends primarily on an understanding of the kinetics of the chemical and physical processes that take place in such operations. This paper will review the current status of kinetics in hydrometallurgy in terms primarily of the author’s experience in diverse unit operations. A distinction will be made between the popular use of models based on limited kinetic data and mechanisms which reflect the actual elementary chemical or physical steps involved in an overall process. Several examples will be used to illustrate this distinction. The proliferation of published papers of declining quality has resulted in the bequest to later researchers of outdated and often incorrect conclusions by a process that is often difficult to reverse. Some examples of these mysterious concepts will be examined and hopefully reversed. Finally, several examples will be given that identify significant gaps in our understanding of the kinetics of important processes that remain unresolved.

Jan 1, 2014

By Mark Sherman

One of the main functions of a process technology and engineering services provider is to select grinding equipment that will meet the client?s throughput rate target. Prudent risk mitigation strategies would suggest that throughput rate estimates be cross-checked using a variety of techniques. Whilst some comminution circuit designers have estimated specific energy requirements via the manipulation of the Bond specific power equation e.g. Barratt?s Grindpower and OMC?s FSAG approach, other designers have opined that the Bond Indices have no role to play in the calculation of SAG mill specific power. As a result, they have developed their own specific energy estimating methodologies, e.g. SMCC?s Drop Weight based power methodology, SPI, SAGDesign, etc. Each method has its supporters and its critics. The challenge facing the engineering provider is how to nominate an SAG mill based circuit throughput rate estimate when faced with significantly disparate specific energies calculated by the different methodologies. This challenge is exacerbated via the continuing evolution of contemporary circuit configurations such as two stage pebble crushing some of which incorporate HPGR technology as the second stage of pebble crushing. The methodology presented in this paper shows that the Bond Indices are an excellent tool for estimating the specific energy requirements for SAG mills in SAB, SABC and SSS circuits. The method accommodates primary crushed feeds, partial and or fully secondary crushed SAG mill feeds, and emulates the impact of pebble crushing on SAG specific energy. As a result, the new Bond Index based method has provided an additional tool for increasing Fluor?s confidence when predicting SAG mill based circuit throughput rates. Based on this outcome, the author proposes that the decades old conundrum of using Bond Indices to calculate SAG specific energies for SAG mill based circuits has been solved.

Jan 1, 2012

By H. Soto, J. Jara, F. Nava

A method has been developed to recover cyanide and copper from cyanidation effluents contaminated with thiocyanate and copper-cyanide complexes. Copper is precipitated as copper thiocyanate or as copper cyanide depending on pH and the concentrations of thiocyanate and cyanide present in the effluent. The copper precipitate presents good dewatering characteristics and can be easily separated from the effluent by thickening and filtration. The solution containing the bulk of the cyanide is then oxidized with ozone to transform the remaining thiocyanate into cyanide. This results in a regenerated solution rich in free cyanide that can be recycled to the cyanidation process. Careful control of the pH of the solution is required. First pH of the effluent is lowered to optimize the precipitation and oxidation stages, then the pH is restored to an alkaline value to regenerate the cyanide solution. Recoveries of over 96% copper are obtained. Free cyanide in the regenerated solution corresponds to up to 160% of the total cyanide contained in the original impure effluent. (The balance being accounted for by the cyanide obtained by the oxidation of thiocyanate). The efficiency of the thiocyanate oxidation stage is 85% to 90%. The method has been demonstrated at bench scale with effluents of various cyanidation plants of northern Quebec. A preliminary economic evaluation indicates that the procedure would be profitable for effluents rich in copper and thiocyanate. This is the case for most barren bleeds of Merrill Crowe and heap leaching operations and also certain CIP tailings of gold ores containing copper impurities. Environmentally the procedure is a better alternative than the current detoxification methods based on the oxidation of cyanide that do not allow for copper recovery and that have difficulties in producing a final effluent with acceptable levels of contaminants such as ammonia, thiocyanate and copper.

Jan 1, 1996

By F. Czerwinski

Mechanically fragmented chips of an AZ91D magnesium alloy were transformed into a semisolid slurry within the Thixomolding® system. Microstructural analysis of a material at various processing stages revealed that the cold deformation of the alloy, experienced during chipping, led to the recrystallization and growth of equiaxed grains which were subsequently converted to the globular structures by melting the grain-boundary network.

Jan 1, 2004