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By J. W. Merks

"The accuracy of a measurement on minerals and ores can be assured by applying suitable and unbiased procedures but its precision is a function of the number of primary increments and their mass, the number of lots per consignment or samples per shift, and the number of measurements on analysis fine samples.Experimental data will be used to show how the variance components for sampling, sample preparation and analysis contribute to the total variance on which precision statements for the final measurement are based. This type of experiment should not only form part of quality control programs at mines and smelters, but also underly the criteria on which the design of manual sampling regimes and mechanical sampling systems for bulk solids and slurries should be based.Sampling systems and regimes can only be adjusted and optimized if the variance component for each step in a quality evaluation process is measured. Knowledge of precision characteristics lies at the core of effective loss prevention and control programs."

Jan 1, 1985

By R. S. Adhikari

It is necessary to assess the physical and functional conditions of highway bridges at regular intervals to ensure they still meet their service requirements. Currently, this condition assessment is mainly performed through visual inspection, which has been identified with several limitations (e.g. the timeconsuming assessment process and heavy reliance on inspectors? personal experience). In order to overcome these limitations and enhance the current inspection practice, this paper presents a novel method for automated bridge condition assessment using a hybrid sensing system. Under the method, existing conditions of bridge components are first captured with a stream of point clouds and color images. Then, the bridge components and the defects inflicted on the components are detected utilizing their visual patterns. The detection results are mapped to the point cloud. This way, the 3D information of the components and defects can be retrieved. The bridge condition assessment can be made effectively through the 3D visualization of this information before carrying out any on-site detailed evaluations.

Aug 1, 2013

By Apoorva Bajaj

Iron ore mines of Steel Authority of India Limited (SAIL) have to comply with strict chemical composition norms laid down for iron ore lumps supplied to its steel plants. This requires a careful planning of the overall ore excavation operation. In general terms, the problem can be stated as: Given the chemical composition of ore for all excavation sites, excavation capacity of each shovel, distance of each excavation site from the crushing plant and the number of dumpers available for transport of the ore, find out the percentage of ore to be excavated from each excavation site such that the production rate is maximized and the chemical composition norm is satisfied to the best possible extent. This paper presents an approach to solve this problem using Branch and Bound method. The specification for r.o.m. quality has been modified by incorporating a new parameter, ?Al2O3 / SiO2? ratio, which has a significant effect on the performance of iron blast furnace.

Oct 1, 2009

By Chuan-liu Wang

The bionic non-smooth surface has the characteristics of anti-wear, and reducing resistance. Based on bionic non-smooth surface?s characteristics, a bionic drill bit was developed. When the bionic drill bit is used, a bionic non-smooth surface forms on the crown of bionic drill bit. This surface can be used to extend the life of drill bit and improve drill efficiency. The bionic unit diameter and arrangement were researched in this paper to determine the optimal bionic non-smooth surface for further improving the life and efficiency of drill bit. Four bionic samples having the same structure size, materials and arrangement were designed and manufactured. After being sintered, the abrasion ratios of the four bionic samples were tested, and the results show that the abrasion ratio of Nos. 3 and 2 were similar (only 2% difference) and higher than that of No. 1 and 4. Therefore, the optimal diameter of bionic unit is 1.5 and 2.0 mm. Small diameter bionic drill bits were designed and manufactured, and tested in the laboratory. The results show that not all bionic structure bodies are better than normal diamond bits, except the bionic unit arranged in a reasonable range. When the angle was 24° and 30°, the arrangement of bionic unit were more reasonable, which shows the superiority of the bionic coupling bit.

Aug 1, 2013

By Z. -G. Ren, J. -S. Qian, Y. -G. Yang

The waste slags from chemical and metallurgical plants contain approximately wt 1% water soluble Cr6+. This hexavalent chromium is very harmful to human health, and the treatment of the slags has concerned metallurgists for many years. A sintering method was developed to treat the waste slag. In this process, sinter was made from a mixture of the waste slag containing hexavalent chromium, iron concentrate and coke breezes. During sintering, hexavalent chromium was reduced to trivalent chromium. The latter is known as a non-harmful material and can be used as chromium resource for the production of ferrochromium or chromium-containing cast iron. After sintering the hexavalent chromium in the sinter could be reduced to less than 0.0008%. It was found that the waste slag with fine particles was favourable to the Cr6+ removal. An increase of carbon content in the sintering mixture could increase the rate of Cr6+ removal and the strength of the sinter produced. The rate of Cr6+ removal increased with increasing basicity of the sintering materials with basicity less than B=1.8, above which it decreased with increasing basicity. Blast furnace was found to operate smoothly when using the sinter made from the waste slag containing chromium. However the productivity of sintering machine was slightly low compared to the sintering operation using ordinary raw materials.

Jan 1, 2004

By M. Olper

Commercial copper plants utilising current best technology are tending towards ever increasing scale, the concentrate requirements of which cannot be serviced by a single mine. In such cases, raw materials are often sourced from different mines, which are often far away from the production plant and usually with very different ore compositions. These plants tend to use the traditional thermal processing steps of smelting, converting to blister, anode refining and casting to produce copper anodes that are then refined in a sulphate electrorefining operation. These thermal steps are in some cases troublesome and require the recycling of considerable quantities of material. A new process was developed taking advantage of the latest developments of the first thermal step of the classic loop, the smelting of copper concentrate to high grade matte or white metal using the well known AUSMELT Top Submerged Lancing Technology. The white metal and/or high grade matte product is converted directly to copper cathode and elemental sulphur using the ECUPREX technology. This approach provides an alternative to the traditional thermal steps of conversion to blister, thermal refining and anode casting, which, especially at small scale, can be expensive and problematic in terms of technical and environmental concerns. At first evaluation, this new process can be operated at low capacities, thereby, changing the traditional approach to copper production. Instead of taking the concentrate to the copper production plant, the copper production plant is taken close to the mine with some significant economic and technical advantages.

Jan 1, 2007

By Claude Bazin, François Robichaud

The control of the operation of a semi autogenous grinding mill is mainly based on power and bearing pressure measurements. Image based sensors can provide on-line measurements of the size distribution of the ore feeding a SAG mill allowing the control of this variable that impacts the operation of this equipment. This paper investigates the potential of using the information from such type of sensor to maintain a SAG mill feed target size distribution by manipulating the speed of the ore extractors below an ore stockpile. A PID and adaptive predictive controller for the size distribution are studied using a simulator for a stockpile and the equipments used for ore withdrawing from the pile. The proposed controller is found to give a good performance while remaining easy to tune.

Jan 1, 2014

By N. Torres, G. Melcher

"An alternative to building new copper smelters, because of either stringent environmental regulations or in order to expand current plant capacity, could be achieved through the retrofitting of old reverberatory furnaces by making use of tonnage oxygen. The CONTOP® technology offers unique advantages over other techniques for this purpose, especially regarding substantial reduction in bath, capital and operating costs. This is possible to achieve since the reverb throughput could be largely increased with no major structural modifications to the furnace.The following options are offered to the smelter operators: dirty concentrates can be treated in an adjacent Contop system, or the cyclones can be mounted on the reverb roof for either dual operation or full Contop operation. ln the tatter case the furnace will be used as a settling chamber and f or slag c1eaning by top blowing with reducing gases.By incorporating Contop technology, the furnace throughput can be increased, higher malle grade, fixation of sulphur from furnace off-gas and substantial savings in energy consumption are possible to attain.IntroductionCopper smelting has been revolutionized during the last quarter century to such an extent that the standard type of plants consisting o f roasters and reverb furnaces seem a thing of the past, or almost. Though the building of new, more energy efficient smelters is a very likely opportunity for a grassroots plant, it would be hardly justifiable to replace an old existing plant unless there are heavy environmental or economic constraints(1,2,3)."

Jan 1, 1984

By M. J. Steffens

ESPLIM is a novel separation technique that combines the advantages of solvent extraction and electrostatic dispersion but its application in the extraction of nickel by the direct solvent extraction route and the effect of high electrostatic field on the stability of organics have not been explored. These were investigated in this study and it was found that the technique allows 97% extraction of the nickel in a single stage compared with 3 stages by the conventional solvent extraction. Also, three months of exposure to 5.0 kV under simulated operational conditions had no adverse effect on the stability of organics.

Jan 1, 2005

By John Lund

INTRODUCTION GOLD-BEARING placers of Alaska and the Yukon Territories are buried under a layer of permanently frozen alluvial overburden, or 'muck', which varies in depth from twenty to one hundred feet. The placers, and the decomposed bedrock layers upon which they are deposited, are also permanently frozen. During the summer, surface muck which is exposed to the sun will thaw, but only to a depth of a few feet. To reach a valuable deposit, the frozen overburden must be either penetrated with shafts, or stripped from the deposit entirely. In either case, before the placer can be mined, it must be thawed. At modern dredging operations, the frozen muck is stripped from the placer by powerful jets of water from hydraulic giants. The placer, and several feet of decomposed bed-rock, are then thawed by forcing water through narrow pipes which have been driven into the deposit. Other methods of thawing frozen placers were used extensively during the early years of the Klondike 'gold rush', but experimentation later proved that creek water at its natural summer temperature was a more effective and economical thawing medium than any other which had been used. EVOLUTION OF COLD WATER THAWING Early prospectors of the far north reached placers by digging shafts through the frozen muck. They then thawed the placer sand and gravel by building wood fires at the bottom of the shafts.

Jan 1, 1951

By Hal. Oliver

MR.]. G. TRAILL: My only excuse for contributing to the discussion on Mr. Hall's interesting paper is that I had the good fortune to be employed at Noranda during those romantic years, 1927 and 1928, when construction was at its height. The mine was in course of being rapidly prepared and brought into production, and the initial difficulties in crushing-plant and smelter were being met and overcome. They were stirring days, and perhaps those members who were with the second Empire Mining and Metallurgical Congress in 1927 sensed the atmosphere of excitement and activity that prevailed. Early History. Noranda must surely possess some of the most remarkable ore-bodies known to mining men, and the story of their development is pure romance. Ed. Horne's faith in the property, and the persistence of Thomson and Chadbourne, were richly rewarded in the end, but only after some very thin times had been experienced. In those early days access to the district was by the Kenojevis river and various portages to Osisko lake, on the shores of which the mine and smelter and the town of Noranda now stand. But all the early work was done on the Chadbourne claims, more than a mile to the west; through the b~sh. I have read a log of the events of that period, and through the whole tale of hard work, discouraging developments, occasional shortages of food, and constant danger from forest fires, can be read the faith and persistence of the men in charge. The Chadbourne ore was of that well-known type which, though just too low-grade to pay (with gold at $20 per ounce), is yet sufficiently encouraging to lead one on in the hope of striking something better. It was only as a last resort that work on the Chadbourne claims was suspended and a diamond drill brought to the gossan-covered hill beside the lake. The diamond-driller told me his version (it may be exaggerated) of how the position and direction of the first hole were decided on. He was told, "You might as well set up your drill here, and drill in, say, that direction". I believe that the first hole went through the richest ore ever found at Noranda. After the drill had gone through about 150 feet of solid sulphide ore running 17 per cent copper and 4 dwt. of gold per ton, it passed into barren rock, but the diamond-driller expressed the opinion (I wonder how he knew)) that the hole would come into ore again before long.

Jan 1, 1937

By S. Hill

For a mining operation, the determination of the best place to build haul roads is typically done by hand, or with the assistance of rudimentary shortest path optimisation algorithms. Straight line, point to point, modelling of costs is often used with distances multiplied by constants that are based on rise of the road between the points. Failings of this approach are that straight line approximations are notoriously poor as they do not take into account areas where a truck cannot travel. In addition, the rise and fall of the road may vary considerably over the truck journey meaning acceleration/deceleration and varying truck speeds are not taken into account. Lastly, the use of rudimentary optimisation algorithms means properties a truck must obey such as minimum turning circles, line of sight restrictions or even that the truck must travel forward at all times are not taken into account. Thus solutions generated may not be feasible, let alone optimal. In this paper we discuss a state of the art parallel Artificial Intelligence tree search technique for solving haul road location problems. As well as the above properties, factors such as road utilisation, cut and fill, and construction costs are taken into account. The combination of advanced modelling and fast computing and optimisation techniques produces significant benefits both in terms of time to generate roads and cost savings. Preliminary results where this method has been used are discussed.

Aug 1, 2013

By Charles Camsell

Few persons ever stop to consider how vital an influence minerals, and especially metals, have had upon human history, how they have affected the every-day life of the individual or how at different periods they have altered the course of nations and determined their progress. Students and writers of history have dealt very fully with political history and have given us a great deal of detail about the careers and policies of kings, parliaments and nations, but frequently have not touched the economic causes that have been the real forces influencing the development and carrying out of these policies. So far as minerals are concerned there is no single work from which one can get a concise and consecutive account of the growth in the use of minerals, nor of the diverse ways in which the. geographical distribution, the .search for, the development and the use of mineral resources have affected human progress from the beginning of man's history. The reason for this is quite plain, and when one takes a little time to think of it he begins to appreciate the magnitude of the job and he will realize that the story of minerals and mineral resources touches a tremendous range of human activity, not only of mining .and metallurgy, but the whole field of agricultural and industrial growth, of exploration and colonization, transportation and commerce, monetary system, commercial policy, in short, almost every phase of economic life.

Jan 1, 1926

By S. k. Kim, H. B. Trinh, R. R. Srivastava

"Spent auto-catalyst is a promising secondary resource of platinum group metals (PGMs), which are being extensively used in automobiles catalytic converters to control the hazardous gaseous emissions (CO, NOx and hydrocarbons). Several pyro or hydrometallurgical routes has been employed to recover PGMs from such spent materials but there is no proper process for recovering the other constituents metals. Therefore, it causes the loss of other major constituents like, Al and Mg along with rare earth metal Ce. In the present study, we investigate the dissolution of Al and Mg using sodium hydroxide (NaOH) roasting followed by a sulfuric acid (H2SO4) leaching; thereby concentrating the PGMs and Ce in leached residues. The effect of roasting temperature, time and amount of NaOH were varied. Subsequently, the dissolution behavior of metals in H2SO4 as a function of acid concentration was investigated from the roasted samples. At an optimal condition for roasting at 600°C with 1:1 NaOH-to-catalyst ratio and 60 min duration, the maximum of Al and Mg were dissolved in 1 M H2SO4 solution at ambient temperature (~25°C). Thus obtained leached residues containing enriched PGMs and Ce content can be treated separately for the recovery of these high-value metals.INTRODUCTION Spent auto-catalyst has been considered as a potential resource for recovering the platinum group metals (PGMs) (Jha et al., 2013). The commonly used auto-catalyst is made of cordierite (2MgO.2Al2O3.5SiO2) in which the chloro complexes of PGMs are impregnated onto the surfaces of porous washcoat of alumina substrate (Aberasturi et al., 2011). The average concentration of PGMs in ore are 2-4 g/ton for Pt, 7-2 g/ton for Pd and 0.2-0.5 g/ton for Rh, whereas, an individual catalytic converter weighing about 1 - 2 kg contains on average 1.56 g Pt, 0.62 g Pd and 0.156 g Rh (Upadhyay et al., 2013). Moreover, recovery of PGMs from spent auto-catalyst offers other advantages like, simple process, low cost and less pollution, as compared to recovery from primary resources (Dong et al., 2015).Therefore, technologies to recover PGMs from spent auto-catalyst has become attractive in the recent past and their recycling contribution has been accounted for 35% Pt, 26% Pd and 36% Rh of the quantity consumed in the production of auto-catalysts (Johnson Matthey, 2016)."

Jan 1, 2017

By J. Koike

Mg alloys for structural application have attracted much attention. However, high process cost and poor mechanical reliability are major concerns upon expanding the application to a wider area. In order to break through these barriers, better ductility is desired at lower temperature. Plastic anisotropy and peculiar twin formation appear to play key roles in the deformation and fracture mechanisms of Mg alloys. In the paper, dislocation slip and twin formation are reviewed. The effects of crystallographic texture and grain size are discussed. The results suggest that a good control of microstructure and texture can improve ductility and mechanical reliability of Mg alloys.

Jan 1, 2006

By W. J. Witte, M. K. Witte

"INTRODUCTION A pilot heap leach project was conducted on the B. P. Selco Hope Brook ore located in southwestern Newfoundland. The pilot heap leach was undertaken to assess and confirm the following:1) To confirm that heap leach technology now currently used in the United States could be applicable to Canadian sites.2) To confirm gold recovery by the Heap Leach technology3) To assess and study potential heap leach environmental concerns in cold and wet climate.PROJECT LOCATIONThe Hope Brook Project is located near the southern coast of the island of Newfoundland, approximately 100 kilometers southeast from Stephenville, approximately 25 kilometers west of Burgeo, Newfoundland. Access to the property is limited to helicopter, float plane or by sea through Couteau Bay. The property was covered with muskeg and very few trees. Surface relief was moderate with many poorly drained boggy sections confined to small areas. Many small unnamed lakes were located on the property which provided water to small brooks and streams flowing to Couteau Bay.Several locations were reviewed for the installation of the pilot heap leach facility. Important parameters used to select a suitable location included sufficient land area, close proximity to but not on the ore body, reasonable protection from wind, sufficient supply of fresh water, close to a suitable location for a portable crushing plant, reasonable access to aggregate material for preparation of the test pad and ponds and suitable contours to minimize site preparation."

Jan 1, 1987

World copper electrowinning tankhouse plant practices have been surveyed. This survey is a supplement to previous surveys that have been carried out in 1995, 1999, 2001, 2002 and 2003. On a world basis, process technology trends include the further installation of automated electrode handling systems including permanent cathode systems, automated cathode handling machines, fully automatic cranes and polymer concrete cells. Designs also have included larger electrode sizes and higher electrolyte flows and current densities. Overall these trends have further resulted in optimized tank house productivities and improved electrowon cathode purity. Most greenfield copper electrowinning projects are occurring in South America and Central Africa.

Jan 1, 2007

By M. Moats

World copper refining tankhouse practices have been surveyed. This survey is a supplement to previous surveys that have been carried out in the 1987, 1991, 1995, 1999, 2001 and 2003. On a world basis, process technology trends include the further installation of automated electrode handling systems including permanent cathode systems, automatic anode preparation and cathode handling machines, section switches, fully automatic cranes and polymer concrete cells. General plant process control has increased with more automation of material handling in the copper refining tankhouse. The general trend for most greenfield copper refining projects remains in eastern Asia.

Jan 1, 2007

By Chunfeng Zhao, Chong Bao, Cheng Zhao, Jiashen Tian, Matsuda Hiroshi

"Based on digital image correlation (DIC) method and self-developed code, the global strain field changing and failure properties of rock-like materials with pre-existing double flaws are experimentally studied under uniaxial compression. By theoretical analysis with linear elastic fracture mechanics (LEFM), the strain approach proves to be practicable to investigate cracking process. Thus, two types of process zone are defined to discuss the specimen’s coalescence evolution at different loading stages. Crack initiation, propagation, and coalescence is a process of zone development and nucleation. DIC strain field results are studied on a meso-level using a strain approach. In the shear coalescence mode, the SPZ (shear process zone) in a bridge area coalesces with each other, while the TPZ (tensile process zone) grows independently. In general, the paper tries to establish the link between microscopic mechanical mechanisms and macroscopic mechanical responses in flawed rock. Further research should be done to study the cracking process and its effect on rock strength in detail by the DIC method.INTRODUCTIONNatural rock contains discontinuities including pores, fractures, inclusions or other defects. The existence of these discontinuities in the rock can decrease the strength and stiffness of the rock and they are a source of initiation of new discontinuities which may in turn propagate and link with other cracks and further decrease the strength and the stiffness of the rock (Sagong & Bobet, 2002). Lots of theoretical, experimental and numerical researches have been done in studying crack initiation, propagation and coalescence in rocks (Hoek & Bieniawski, 1965; Kranz, 1983; Reyes & Einstein, 1991; Park & Bobet, 2009; Gonçalves & Einstein, 2013). But when it comes to multiple pre-flaws, the issue that how the preexisting flaws affect each other becomes complicated and uncertain. The stress field around the tips of flaw can either enhance the impact of single flaw or weaken it. According to the observations have been done before, it is found that the way and function in which these cracks propagate and coalescence depends on the geometric arrangements (Bobet, 1997; Bobet & Einstein, 1998; Wong & Chau, 2001)."

Jan 1, 2015

By John E. Udd

"In this paper the author presents the results of the 1992 CIM survey of graduates in minerals and technology programs in Canadian post-secondary institutions. As usual, the trends are out-of phase with the economic state of the industry. People who chose a minerals career in the prosperous days of the late 1980sare now entering a labour market in recession.The cyclical nature of enrollments is illustrated in a series of figures showing the trends since the CIM survey Wa5 begun in 1956 (and even earlier for mining engineering).In the survey, the respondents were asked to provide comments on their perceptions of the problems specific to minerals education in Canada. The large number of responses have led the author to the conclusions and recommendations given in the final part of the paper."

Jan 1, 1993