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By Li. S., C. Sili

Abstract. Study on nonlinear damage localization process of rocks under water chemical corrosion is a more interesting topic in rock mechanics research world widely. It is very important in estimating long term stability of rock engineering, design of nuclear waste repository and its performance estimation, geothermal and petroleum development. This paper reports that new development of study on the topic, including methodology, results of meso-mechanical test, real-time CT scan test and acoustic emission test, temporal fractal behaviors, neural dynamic modeling and chemical-induced damage law, etc. This paper also discusses the research directions of the topic in the near future. Zusammenfassung. Untersuchung zum durch die chemische Corrosion induzierten Schaedigungsprozess ist einer der Trends im Gebiet der Felsmechanik. Sie ist zugleich ein sehr wichtiges Forschungsprojekt u.a. fuer geotechnische Langzeitstabilitaetsanalyse, Langzeitsicherheit eines Endlagers, Erdwaerme- und Erdoelfoerderung. Dieser Aufsatz stellt die neusten Entwicklungen in den folgenden Teilgebieten zusammen: Untersuchungsmethoden, Laborversuchsergebnisse der Mikromechanik, der Computer-Tomographie und der akustischen Emission, zeitabhaengige Fraktaleigenschaften, Modelle fuer die Nervendynamik sowie Modelle fuer chemie-induzierte Schaedigungen. Zum Schluss werden kuenftige Forschungsschwerpunkte bzw. –richtungen diskutiert. Résumé L’étude du processus de la localisation de l’endommagement du à l’érosion chimique est un thème d’actualité pour la mécanique des roches. Elle est également un sujet de recherche d’importance dans l’évaluation de la stabilité à long terme des ouvrages rocheux, l’analyse du system de stockage des déchets nucléaires et l’évaluation de son comportement, l’exploitation de l’énergie thermique et pétrolifère, etc. Cet article présente le développement actuel dans ce domaine, incluant la méthodologie d’étude sur le processus de la localisation de l’endommagement dû à l’érosion chimique, l’analyse des essais mécaniques avec l’observation microscopique, du balayage en temps réel (CT), et de l’émission acoustique. On aborde ainsi modèle des caractéristiques fractural du temps, le modèle de la mécanique dynamique neural, ainsi que la loi de comportement d’endommagement dû à l’effet chimique. Enfin, les perspectives relatives à ces études sont présentées et discutées.

Jan 1, 2003

By M. P. Ristenbatt

A new automated post-disaster signaling system, intended to use through-the-earth EM propagation, was demonstrated in the laboratory at an input SNR of -34 dB. The system presently available requires an input SNR of +6 dB, and uses a human-ear detector. The work here demonstrated coherent integration, for the automated system, in multiples of 17 s, up to 1088 s (18 minutes). A repeating pseudorandom (or pseudonoise) signal is used, which offers an ideal auto-correlation at the receiver matched-filter output. A novel decision-variable algorithm achieves the estimate of noise level by using those matched-filter output samples that occur between the signal auto-correlation peaks. This work included corraboration that the received signal power decreases as distance to the tenth power, for through-the-earth propagation. Thus, the above 40 dB reduction in required input SNR permits an automated system to have a range 2.5 times that of the present system. In addition, an automated system permits the possibility of operating receivers around-the-clock; this would reduce the initial-detection-time from a few hours (present system deployment time) to a few minutes (signal processing time).

Jan 1, 1981

By Andrea M. Ouchi

A major focus of ground control research presently being conducted by the Geomechanics Group in the University of British Columbia Mining Engineering Department is to incorporate weak rock masses (RMR76 less than 50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented by mapping of one mine in Montana and of several mines within the Carlin and Getchell Trends of Nevada. In addition, a neural network analysis has been performed and modifications of the span design curves at the lower RMR76 range have been made. The common factor in all the above mentioned mines is a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be dealt with to safely extract the mineral bearing rock. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2004

By O. P. Garg

"The Iron Ore Company of Canada (IOC) operations in Labrador and Quebec, in Canada, is among the largest openpit mining complexes on a world wide basis. Since the 1981-82 recession, IOC has embarked on a comprehensive cost reduction and productivity improvement program in order to survive in the world iron ore market.This paper will outline the approach used in prioritizing the cost reduction items.IntroductionMuch of the mining industry in North America is in a crisis state. Most producers are operating at production levels well below capacity, some have been merged or sold, while others have been mothballed or closed permanently. For many of us still operating, the future is uncertain. Despite the many cutbacks and closures, there is still an abundant supply of minerals in the world market and there is almost no hope for any relief on price pressures on most mineral commodities in the near future. The Iron Ore Company of Canada (IOC) operates an iron ore mine, a concentrator and a pellet plant known as the Carol Project located in Labrador City, Newfoundland. This concentrator and the pellet plant have the annual capacity to produce 20 million and 10 million tons respectively. A company owned and operated railway links this operation with the dock terminal facilities in Sept-Iles, Quebec.In the past decade the Iron Ore Company of Canada has been one of the largest producers of iron ore products in the world. Its pellets and concentrates as well as natural ores were sold in North America, Europe and the Far East. In 1981-82, sales, particularly in North America, went into a serious decline. For almost 30 years, the gospel IOC preached to employees was ""production, production!"" There were many innovations, and millions of dollars were spent on the biggest and best equipment, on research and development, on training and developing employees."

Jan 1, 1987

In common with general experience in the iron-making industry overseas, Australia has in recent years suffered a deterioration in the physical quality of her iron ores in their suitability as a direct blast furnace feed. The increasing amounts of fines and the more friable nature of lump ore, especially in the ore from the Cockatoo Island deposits in Yampi Sound, Western Australia, have focused attention on problems of ore preparation and agglomeration, particularly sintering.Although very small pilot scale Dwight-Lloyd type sinter machines were operated at the steel-making centres at Newcastle and Port Kembla during World War II, no sizeable capacity was installed, so that ore was charged to the blast furnaces almost entirely unscreened, and the resultant flue dust was stockpiled.Towards the close of the war, the pilot plant at Newcastle was replaced by a small machine, adjacent to the flue dust stockpile, with a rated capacity of some 20 tons per hour. After approximately five months of part-time operation, this plant was closed down in January, 1945. Production was not resumed until December, 1950, when, due to a temporary ore shortage, it was decided to supplement available ore with sinter produced from the large flue dust stocks of about 300,000 tons. In spite of mechanical and process difficulties, inherent to the design of the plant, operation was continued on a two-shift basis, with several shutdowns for extensive overhaul and plant alterations, until September, 1954, when production was put on a three-shift basis. Addition of Yampi ore fines to the sinter machine burden was not commenced...

Jan 1, 1957

By J. P. Morris

An experimental blast furnace in normal operation was quenched by substituting cold nitrogen for the hot blast air. More than 2,200 samples from the stack, bosh, and hearth were taken; 500 of these were selected for detailed analysis. Deductions are made as to the patterns of burden movement and gas flow; the reduction of iron oxides, including a comparison of ore and sinter; and the behavior of sulfur above the smelting zone. Metal and slag beads from the bosh were analyzed, as were samples from the hearth metal and slag. A brief description of a petrographic examination of the quenched burden is included.

Jan 1, 1963

The 23rd annual American Mining Hall of Fame Awards Banquet sponsored by the Mining Foundation of the Southwest will be held at the Tucson Marriott University Park Hotel, Tucson, AZ on Saturday, Dec. 3, 2005. The Mining Foundation of the Southwest is a non-profit organization. It educates the public about the mineral industries and reports outstanding accomplishments in the fields of mining and the earth sciences. This year’s inductee, guest of honor and featured speaker at the banquet will be Pierre Lassonde, president of Newmont Mining and resident of the World Gold Council. He is one of Canada’s leading gold analysts.

Jan 1, 2005

By Cathy Aimone-Martin, Robert Brentar, Brent Meins, James Lauer

Vibration measurements of multi-story structures in an urban environment began 3 years ago in New York City during close-in blasting to adopt correct measurement procedures and recommend revised ground vibration limits that best characterize cracking potential in mid- to high-rise structures. Two broad categories of structures included non-engineered 4- to 6-story multi-family unreinforced brick masonry buildings, built from the late 1800s to around 1930, and post-WWII, high-rise structures of reinforced concrete and steel rising 12 to 40 stories. In-ground vibration limits similar to those recommended by the U.S. Bureau of Mines safe criteria, developed for 1- and 2-story residential structures, are imposed by the New York City Fire Code. However, these limits are often lowered by project engineers or New York Department of Buildings when blasting is planned near buildings designated Landmark or historic and classified as fragile or vibration-sensitive. Seismograph measurements to determine compliance with in-ground velocity limits currently employ geophones mounted to basement walls and on concrete slabs overlying rock. These measurements cannot be correlated with upper structure cracking potential and are often exceeded, resulting in excessive and costly downtime to allow post-blast damage investigations.

Jan 1, 2014

The steps for the beneficiation of iron ores differ from ore to ore, depending on the mineralogical phases of the particular iron ore and the nature of the association of the gangue minerals with iron oxide in that ore. The extent to which the beneficiation can be undertaken economically depends both on the amount and the nature of the gangue. The analysis of the phases present in an orebody optimises the mining and process operations (separation, beneficiation, sintering, etc).X-ray diffraction (XRD) provides qualitative and quantitative information about the main ore phases as well as the gangue mineralogy and the amorphous content present in a sample. In addition, modern quantification methods such as Rietveld refinement allow the calculation of the distribution of elements in solid solutions such the substitution of Fe with Al in goethite or hematite.The use of high speed detectors has made XRD an important tool for grade and process control. Finger printing of XRD data can facilitate multi-dimensional mapping of ore deposits and drill cores, identifying regions of favourable mineral compositions. Grade control using XRD can be completely automated and controlled remotely.The two case studies in this paper demonstrate how XRD and finger printing can be used for grade control, process optimisation and quality control of a goethitic and a magnetitic iron ore. The enormous potential of XRD as an inexpensive, reliable tool, useful in the characterisation of iron ores will be demonstrated.CITATION:K÷nig, U, 2013. Application of x-ray diffraction to iron ores - potential implications for grade control and downstream processing, in Proceedings Iron Ore 2013 , pp 275-280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By R. L. F. Kay, T. A. Fletcher, A. J. Boyce, C. M. Rice

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. The synorogenic, mafic Ordovician intrusion comprises orthopyroxene-rich xenoliths and mafic-ultramafic cumulates with low-grade pyrrhotite, chalcopyrite and pentlandite mineralisation. Despite abundant textural, mineralogical and O isotope evidence for significant assimilation of country rocks, S isotopes indicate only a modest uptake and suggest that mineralisation is dominated by magmatic sulphur. The preferred explanantion is that the magma was close to S saturation on emplacement. Uptake of elements such as Si and O led to early crystallisation of orthopyroxene, resorption of olivine and early segregation of a sulphide liquid. Post-magmatic interaction with a high-temperature, surface-derived fluid, whose movement may have been controlled by regional shear zones, reset biotite and whole-rock O isotope values but not those of orthopyroxene. This model identifies the presence of olivine-rich rocks and evidence of extensive assimilation as guides to prospectivity

Jun 19, 1905

By Daniel Bennett

There are few methods currently applied towards on-line bulk mineralogical analysis. Yet on-line knowledge of process mineralogy could potentially provide large benefits, such as increased extraction efficiency or resource optimization. The work described in this paper involves the development of radio frequency methods for bulk mineralogical analysis. Some resonances that occur in the radio frequency spectrum are mineral specific, and potentially allow quantitative estimation of mineralogy in an ore stream. Results will be presented on the specific detection of chalcopyrite. Initial quantitative measurements investigating matrix effects have indicated the feasibility of on-line mineralogical estimation using radio frequency techniques.

Jan 1, 2006

By R P. Callaghan

Underground production from the low grade copper orebodies at Mount Lyell in recent years has involved surface subsidence of open cut areas. Relevant structural and lithological features of the geological environment are described. The highly mechanised underground mining system involves sublevel caving and sublevel open stoping with associated hanging wall cave. Monitoring of subsidence and caving has been made by regular visual inspection and measurement of crack development, and by surface profile surveys. These simple techniques have proved adequate in assuring management that ground movement is proceeding normally and safely.

Jan 1, 1980

By M. W. Lewis, J. Werner

Fluctuating metal prices, declining head grade, and increased operational costs are forcing many open pit mining companies to look to their balance sheets for significant cost reductions in order to remain competitive. Maintenance continues to represent a significant proportion of the total operating costs in the mining industry. Compared with the other major cost components of the mining process, very little effort has gone into maintenance optimization. The potential payoff from maintenance optimization on the cash cost of the commodity is enormous. A large percentage of these costs are incurred in unscheduled maintenance events, which typically cause serious disruptions to the production process. These maintenance-induced production losses can be a significant contributor to the overall operating costs. A structured proactive maintenance approach using the latest advances in technology can achieve dramatic cost reductions and productivity improvements. Remote condition monitoring systems are becoming increasingly commonplace and have the potential to identify problems prior to failure. Detection of equipment degradation prior to failure will enable repairs to be scheduled thereby reducing costs and interruptions to production. Remote condition monitoring technology has evolved rapidly in recent years, with a host of new tools becoming available to assist mine operators in improving their maintenance operations. These tools have capabilities such as remote real-time vital signs and performance monitoring, alarm/event handling, trend analysis, and maintenance workflow management. When these monitoring tools are used in conjunction with a mine management system, the vital signs data can be integrated and associated with maintenance history, predictive maintenance data, operational information, and geographical information. This integrated approach to the management of vital maintenance data will help shift the mobile equipment maintenance paradigm from reactive to proactive. This paper will introduce a proactive approach to the management of the maintenance process and the tools required to facilitate this process.

Jan 1, 2005

By H. L. Riley

Cleaning and handling of fine coal are generally conceded to be more difficult problems than preparation of the coarser sizes. Increased mechanization in the coal-mining industry has, in general, resulted in an increased percentage of the fine sizes in the total coal mined. If the coal fines are cleaned by wet methods, the minus-1/16-inch square-mesh particles cause most of the sludge and slurry problems encountered in preparing wet coal. Equipment that separates coal from refuse on the basis of specific gravity is not efficient on sizes that, because of their fineness, do not follow the same laws of hindered settling as the larger particles. Probably the best solution of fine-coal cleaning problems is to use other methods, such as flotation, that utilize other physical characteristics than those determining hindered-settling ratios. Regarding the type of flotation known as the Elmore vacuum-flotation process there has been a scarcity of data and information available in this country. An investigation has therefore been made to obtain additional date and information on this process under laboratory conditions. During this investigation an effort has been made to evaluate the relative efficiencies of vacuum and mechanical laboratory froth flotation cells. The investigation included float-and-sink, screen-sizing, and flotation tests on 2 different samples of 14-mesh to 0 raw coal and an a sample of slurry from the settling-tank overflow of a typical washer. One raw-coal sample was obtained from the American bed and represented a type of coal that is relatively easy to clean. The other raw-coal sample was from the Mary lee bed and represented a type considered difficult to clean.

Jan 1, 1954

By E. Lammer

"Underground mining processes are dangerous. The design of mining equipment, which is able to cope with the hostile underground environment, is a challenge for all machine manufacturers. Presupposition for realizing the vision of SANDVIK for zero harm for working with SANDVIK equipment is the installation of the appropriate processes. Into the product engineering and product development processes of Sandvik Mining and Construction, a specific "Product Safety Process" has been integrated, where all safety related activities like identification of all life cycle hazards, risk management and safety verification / validation are planned, performed and documented. Product safety shall be „designed into" the products. Therefore, specific research activities have been started, to address the safety and health related topics for the development and for the engineering of SANDVIK mining machines."

Jan 1, 2011

By Tapan Goswami

The expectation from the blasting engineers and shotfirers is often that explosives will perform optimally at all times. However, in reality, non-ideal situations exist on mine sites and occurrences of poor explosives performance are common. Often the cause is difficult to identify. Having a good application technique and analysis skills will minimise the risk of poor performance. This paper will discuss the experiences gained by the author while blasting in the Hunter Valley, Australia.

Jan 1, 2003

By G. C. Lammers

The object of this study was to determine the economic feasibility of hydraulically transporting Sandow (Tex.) lignite 100 miles and dewatering and thermally drying the transported lignite to a surface-dry condition. The most important factors involved in the feasibility of hydraulic transport, are the degradation incurred during transit, the length of the line, and the cost of alternative methods of shipment. In pipeline tests in which roughly 75 miles of hydraulic transport was simulated the percentage of minus-325-mesh solids increased from about 1 to 41 percent for both lignite and bituminous coal; in the micron sizes the coal fared considerably better than the lignite. Such degradation, even though it enhances flow through the pipe-line, severely aggravates the dewatering problem on lignite. Cost studies indicated that continuous vacuum filters offer the most economical means of dewatering minus-1/8-inch material. Surface moisture, if high, must be removed by relatively expensive thermal drying.

Jan 1, 1958

One of the most significant problems experienced in land reclamation work has been the tendency of earthmovers to over-compact the subsoils and topsoils. The need for extensive subsoil drainage, because of over-compaction, becomes a very expensive exercise and can be attributed to poor planning. The problem has been addressed both at the Waihi and Huntly open-cast mines through the use of low ground pressure machines in the placement of subsoils and contouring. The use of subsoilers working to contour to aerate the soils is essential to integrate both the sub and topsoils so that significant root growth and drainage is established. Waihi's rainfall (approximately 200 mm annually) and light soils create difficulties in preparing for the final seed bed. A noticeable factor in preparation of the growing medium was the reaction of the lime particularly in the subsoils (damp), from a lumpy, quite heavy texture to almost a seed-bed texture within a period of approximately 72 hours. Also the high incidence of stone and debris which was not apparent in the placement of subsoils meant the job became very labour intensive. This will be overcome with the importation of a machine from the USA. All of the rubber tyred tractors used on these projects are four wheel drive in the 6S-aOhp range which for weight distribution and the safety factors allows for good landscaping techniques. Good engineering practices should ensure that slopes of no more than 3:1 be designed, keeping in mind that the long term planning must allow for maintenance and stock management of restored land.  In the preparation of the final growing medium the equipment used included: Caterpillar 05 LPG and blade; three-four wheel drive rubber tyre tractors; Super flow subsoiler; hydraulic twin spinner manure spreader; discs û two types; harrows; MF Seeder; Cambridge Roller and Duncan Rotatiller.

Jan 1, 1991

Some of the problems associated with drill core evaluation of alluvial tin deposits and correlation with plant-scale recovery are discussed. Panning churn-drill cores on site tends to undervalue such deposits because of failure to recover completely all the available liberated cassiterite, and secondary gravity processing may also fail to give an accurate determination of potentially recoverable tin. However, by using a combination of heavy liquid separations, x-ray fluorescence analysis for Sn, and normal methods of reflected and transmitted polarized light microscopy, a quantitative assessment of alluvial material can be carried- out. The information obtained may include the liberation characteristics and distribution with size of the cassiterite, the nature and quantities of the various gangue minerals, and the amount of potentially recoverable cassiterite in the material as compared with the amount locked with light gangue minerals and hence difficult or impossible to recover. In addition, an analysis of the efficiencies of the various gravity processes, such as panning, jigging, and tabling, used to determine "recoverable tin" in the alluvial material, can be carried out. A detailed example is given of this type of investigation, in which an assessment was made of a churn-drill core from Uncia, Bolivia.

Jan 1, 1970

By Julie Culverhouse, Dennis Grimm, Kieran Harding, Jean-Francois Boulanger

"Agrium’s Canadian Phosphate Business (CPB) is comprised of Kapuskasing Phosphate Operations (KPO) in Northern Ontario, Canada’s only operating phosphate mine, and Redwater Phosphate Operations (RPO) in Alberta, which manufactures the fertilizer from KPO’s concentrate.Production from KPO’s South Pit commenced in 2009 and introduced contaminant problems: high aluminium from crandallite and kaolinite clays. These issues caused a drastic decrease in P2O5 recovery and throughput in both plants. KPO attempted to reduce Al clays by means of aggressive desliming. Meanwhile RPO experienced high amounts of dissolved metals in their feed that are detrimental to fertilizer production.This paper covers the mineralogy of the problem, its impact on contaminant separation at KPO, on RPO’s process and on Agrium’s Canadian Phosphate Business as a whole.Potential solutions to the problem are discussed and analysed, including a process change to deslime high aluminium streams more aggressively and high grade ore flotation, which is atypical at KPO. The latter is a demonstration of the value of communication between the concentrator and the client, as KPO accepted a recovery loss and increased production costs in order to increase overall CPB profits. General lessons learned are discussed, followed by a section on ore blending.INTRODUCTIONAlthough the existence of the Kapuskasing phosphate deposit has been known since the 1970s, it’s only since 1999 that Agrium has been operating the Kapuskasing Phosphate Operations (KPO). The mine consists of three major pits (Center, North and South) from which a mining contractor hauls the apatite ore to the Agrium concentrator. The beneficiation plant processes the ore, separating contaminants such as Fe, Mg and Al which are detrimental to its client, Agrium’s Redwater Phosphate Operations (RPO). The KPO concentrate is finally thickened, filtered and dried before being shipped by rail to RPO.At the Redwater plant, the KPO concentrate is added to a sulfuric acid solution in an attack tank, to create a phosphoric acid solution and gypsum:"

Jan 1, 2011