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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 Godfrey W. McDonald, Dennis E. Fredrickson

"Commercial coal mining has been recorded in Nova Scotia since 1863 and during this period an estimated 60,000,000 short tons of mine discard containing 10 1030% coal has been accumulated, Approximately 70% of these dumps are in the Cape Breton region and most are owned by the Cape Breton Development Corporation (CBDC), formerly DEVCO.The explosion of oil produced energy costs which created an increase in thermal coal demand as well as the desire to rehabilitate abandoned mine dumps encouraged coal reclamation. CBDC was receptive to a proposal from the Selminco Joint Venture and encouraged the building of the Princess Recovery Plant (1980) and The Summit Plant (1982).The mine dump contains scrap, waste rocks, coal and substantial quantities of fine shale. The scrap and oversize are removed and the remaining material slurried with water to a density of 1.45. The slurry is cycloned to separate the saleable thermal coal from the rejects which are returned to designated areas of the dump for contouring and revegetation.BackgroundThe recorded coal production in Nova Scotia from 1863 to 1980 was 390,000,000 short tons. This extraction was associated with an estimated 60,000,000 short tons of discarded material. This mining discard and coal washing plant reject are located in numerous, varying sized dumps throughout the mining areas. Approximately 70% of these dumps are in the Sydney coal field region of Nova Scotia. The coal content of these dumps varies from 10 to 30% coal with an average of 18%.Energy CostsThe explosion o f energy costs in the mid-1970s greatly increased the sale price of thermal coal which made recovery of coal from some of the dumps economical. The environmental benefit of these operations will be the rehabilitation of the dumps upon cessation of the coal reclamation operation."

Jan 1, 1983

By J. W. Matousek

"More copper concentrates are treated in flash smelting furnaces than by any other process, and such furnaces are located in most of the world's major copper producing areas. Except for perhaps two furnaces treating chalcocite-type materials, little difference is seen between the grades of the concentrates being smelted. Within individual smelters, even less variation in feed grades is found. This is both accidental and intended. Many furnaces treat concentrates from captive ores, and these tend to be of relatively constant composition over long periods. Toll smelting operations blend concentrates to ensure delivery of feeds of fixed compositions to their furnaces to avoid upset conditions. Matte grades vary between flash smelting furnaces, but most commonly, these are the result of differences in operating practices rather than because of differences in concentrate grades. This paper reviews an industrial flash smelting test in which the copper content of the furnace feed was intentionally altered over a wide range. IntroductionExcept in a few copper mining regions of the world, the principal copper mineral is chalcopyrite (CuFeSz). This results in the almost universal production of concentrates containing 25070 to 30% copper (and similar amounts of iron and sulphur). Many operators of copper flash furnaces spend their entire metallurgical careers smelting concentrates of essentially fixed grades. This is true both of smelters treating concentrates from captive mines and those processing concentrates on a toll basis. From the production staff's point-of-view, the less variation in grades seen by the furnace, the better. Fixed analyses of concentrates and constant feed rates produce consistent quantities of matte at a consistent grade for processing by the converters. The result is, even in smelters treating a variety of concentrates, efforts are expended in sampling and blending to ensure feeds of relatively uniform compositions being sent to the furnaces."

Jan 1, 1993

For the last few years, a new and innovative technique has been successfully used to determine refractory and castable thickness in various metallurgical vessels. The acousto ultrasonic-echo (AU-E) technique uses stress waves to detect metal penetration and delaminations within refractory linings. In addition, it is capable of measuring the thickness of refractory layers and build-up material. The inspection and measurements can be carried out while the furnace is in full operation. The present paper discusses the principles of the AU-E technique, and its advantages and limitations. A number of case studies are presented to demonstrate various capabilities of this new Non-Destructive Testing (NDT) technique.

Jan 1, 2005

By J. A. Finch

Solvent-coated air bubbles in the Air-Assisted Solvent Extraction (AASX) process achieve the dual role of high solvent specific surface area and ease of phase separation. The thickness of the solvent film is of fundamental interest but difficult to measure directly in the process itself. As an approach interferometry (in the UV-vis region) was used to measure the time dependent thickness of a film formed by blowing an air bubble in kerosene-based solvents. The film was stabilized by the presence of 1.5 ppm silicone oil, as employed in AASX. The film appears to comprise two layers; an outer "free" layer of almost constant thickness and an inner "bound" layer which decreased in thickness with time. The bound layer is considered relevant to AASX. For a 20 mm diameter bubble blown in LIX/kerosene solvent the initial thickness was ~ 3 um which decreased over 10 minutes to a final rupture thickness of 500 nm. The bound layer thickness and time to rupture decreased with decreasing bubble size. Correspondence to prior indirect estimates of solvent layer thickness is examined.

Jan 1, 2006

By P. M. Shibley

"IntroductionMine drainage, surface. drainage and process liquors are the principal mine and mill effluents. The quantity and quality of these flows varies according to mineralogy, type and scale of mining, the process, tailing disposal, local ground conditions and climate.Typical contaminants remaining after solids sedimentation are colloidal or semi-colloidal particles, acids, alkalis, metals in solution, cyanides and thiosalts. Environmental regulations and guidelines have been issued in detail by the appropriate government agencies and will not be reviewed here. Revisions and additions are being made as our comprehension and abilities increase. Some contaminants of consequence have not been specifically regulated as practical treatment technology has not been identified. Thiosalts fall into that category as do the derivatives of the first stage of cyanide oxidation - cyanates.Most mining activities have present or foreseeable water treatment requirements. Because process economics can be adversely skewed by the environmental factor, the acknowledged objective of every operation must be to identify and anticipate those requirements.The evaluation and selection of water treatment techniques for mine-mill applications is complicated by the fact that most mine-mill effluents are high volume, dilute and chemically complex systems. Treatment processes applicable to most contaminants are: chemical or biological oxidation; neutralization and/or precipitation; liquid/solids separation. Other processes such as ion exchange, electro-deposition, foam fractionation, freeze crystallization and reverse osmosis offer the possibility of selective removal or concentration of contaminents. The latter tediniques, representing a slightly higher level of technology, are less suited to the large, low value flows usually encountered in the mine environment."

Jan 1, 1989

By Brendan Parker, Tyron Rees, Steven Hart, Abba Manesh, Ian Mcgaffin

"In September 2009, Newmont began the commissioning of a 3 stage crushing and milling circuit at its Boddington Gold Operation in Western Australia. The Boddington ore has been recognized as one of the hardest and most abrasive ores treated to date and this played a pivotal role in the selection of crushing and HPGR technology for this operation as opposed to the more conventional SABC circuit.This paper will examine the scale up from laboratory to pilot plant and full scale operation of the crushing circuit. There have been many challenges to overcome in the first 18 months of operation; however, the HPGRs have in general met design expectations and performance is expected to improve further with ongoing design changes"

Jan 1, 2012

By C. -M. Katsari, G. N. Anastassakis

"Copper is considered one of the most important industrial metals because of its properties (conductivity, malleability) and variety of uses. Approximately 70% of the global copper is used for various electrical applications, with a significant part of copper originating from recycling, since copper can be recycled and re-used countless times, without any loss of performance and difference in the quality of recycled copper in comparison to that from ore. Copper recycling significantly contributes to natural resources conservation, waste minimization, energy saving, and overall cost reduction. Approximately, 35% of the globally produced copper originates from recycled copper.The objective of the current work is to investigate the recovery of copper from electric wire scraps using wet shaking table as an alternative to air separation methods that prevail over the wet ones in recycling processes. The tests were carried out using feed of correspondingly high- and low-grade in copper. In the first case, the wire scraps had been subjected to shredding only, prior to tabling separation; in the later, the low-content tailing of prior air separation was used as feed ?n table separation.In regard to testing, the following factors were examined: table tilt, water flow-rate, and reciprocating speed. The results of the tests clearly denote that copper wire separation from plastic polymer is feasible, as in most cases, table separation resulted in heavy products of high purity in copper and high recovery, and tailings of very low copper grade. The results of the current work clearly denote that wet tabling can be applied efficiently for the separation of recycled copper wire from plastic, as an alternative to air separation methods, as well as for the recovery of copper from the low-grade tailings derived from air separation methods."

Jan 1, 2016

By Alfredo Bambaren

First Encounters between Communities and Mining 1. Importance, meaning and process 2. Antamina?s study case 3. ?Self-organization? theory (NLP) 4. The story we tell, the values we live 1. Importance, Meaning and Process ? First encounter stays in mind as a model. ? First encounter means foundation. ? First encounter builds the story.

May 1, 2010

By Kiran B. Chaudhuri, Michael Koch, Jorg Lema Patino

"Stricter pollution regulations together with other factors have stimulated interest in the modernization of the traditional sinter - blast-furnace lead operation. In this context, direct smelting methods have again come into prominence. Consequently, the Kivcet Lead Smelting Process, which belongs to this group, has attracted the attention of the lead producers of the world. The Kivcet Process offers the advantage that lead and zinc can be simultaneously recovered in a single furnace unit. KHD Humboldt Wedag A G, Koln, Federal Republic of Germany, has signed a contract with the Sociedad Complejo Metalurgico de Karachipampa of Bolivia for the delivery of a turn-key Kivcet plant, which is expected to be the first plant of its kind in commercial operation. This paper describes the design and expected operating data of the plant."

Jan 1, 1980

By Rene A. Morin, John K. Kebe

"As explosives become more widely used in urban and other congested areas, governmental regulations pertaining to their use are becoming more pervasive and stringent. This is forcing the blasting industry to review its entire spectrum of operations. Greater attention is now being paid not only to the design and layout of blasts, but also to the monitoring and recording of their after-effects for both legal and business reasons.Current PracticesThe major users of explosives in urban areas are quarry operators and construction companies. A characteristic of both of these industries, at least in recent years, is a relatively low margin of profit. This, coupled with the fact that their use of explosives is relatively intermittent, prevents them from having the kind of professional consulting services that blasting operations really warrant in today's regulatory environment. When such services are obtained, they tend to be directed more at the design and execution of the blast than at the recordkeeping function. The records that are kept tend to be more in the form of a summary of the consultant's design data as opposed to the kind of after-effect detail that is necessary.The more experienced consultants and operators now realize that at least as much attention must be paid to the record-keeping as to the design work. Regulatory bodies at all levels of government are insisting on the availability of such records.Unfortunately, the instrumentation in use today for taking such measurements does not lend itself to the practice of intermittent consulting. Current monitoring and recording instruments are based on so-called analog technology of the type that has traditionally been applied to the monitoring of earthquakes. They require set-up and calibration procedures which must be repeated each time the instrument is moved, or the blasting parameters are changed, as well as complex total analysis of the recorded data. This can lend to confusion and a dilution of responsibility for anything other than the design work and possibly some summary reporting."

Jan 1, 1985

By R. F. Dawson, A. S. Bagnall, K. Barron

"At Smoky River Coal Limited (SRCL), economic occurrences of structurally thickened coal deposits form attractive surface mining targets. These steeply dipping, structurally complex deposits require that special attention be given to pit wall design and operational practices.Where anchor support is feasible, there is potential for reducing footwall waste requirements and/or increasing coal recovery. SRCL has used rock anchors to support footwall slopes since 1985. This paper outlines design considerations and performance of rock anchor support systems at SRCL.Three case histories are included that illustrate the design process for supporting steeply dipping footwall slopes using rock anchors.IntroductionWestern Canada contains vast reserves of high grade coking coal largely located in two belts within the Rocky Mountain Foothills straddling the Alberta/British Columbia border. There are about one billion tonnes of ""clean"" coking coal reserves (Romaniuk and Naidu, 1986) situated near existing mining infrastructure. Within the reserve areas shown in Figure I, a total of six producers operate 10 large mines linked with ports situated on Canada's west coast. Al! of the producers operate conventional shovel truck surface pits.Surface mineable reserves within some of the mountain coal mines are located on dip slopes or where the geologic structure has thickened the coal near the surface, creating low strip ratio targets. Footwall slopes in these mines are developed parallel to bedding, thus minimizing waste extraction and preventing undercutting of potentially unstable strata. The base of the mineable coal measures in both north and south regions is marked by massive quartz sandstone units (Torrens Member and Moose Mountain Member) which often form the footwall. Footwalls developed within this basal sandstone unit can attain very high unbenched heights often with little risk of instability. In cases where the footwall is developed on weaker strata above this basal unit, stability considerations control slope height when bedding dips exceed about 30°. In these situations it is desirable to assess the benefits of artificial support to increase the unbenched footwall slope height."

Jan 1, 1995

By R. B. Roberts, A. L. Mular

A simple way to determine the IEP of oxide minerals is described. The method is shown to apply for fine powders of Fe203 and ZnO. The IEP lies at pH 6.95 for Fe203 and at pH 9.08 for ZnO.

Jan 1, 1966

By H. Sipilä, H. Vartiainen, H. Paarma

"The carbonatite massif of Sokli includes several low-grade Nb showings composed of ores and wastes as identified by routine analyses. More detailed lithologic proportions were determined in two orebodies in the Kaulusrova Nb-mineralized area by a careful geological study and by thorium radiation measurement on 10 cm-long drill core cuttings with a total length of 460 metres. The distribution of Nb in eight X-ray spectrometrically analyzed drill core sample intervals (totalling 35.8 m) was determined by analyzing the intervals semi-continuously by an X -MET analyzer. The geological studies suggest that Nb-mineralized bodies are feasible fo r the sorting of are and waste. This was confirmed by the semi-continuous determination of Nb on the X-MET analyzer.IntroductionThe Sokli carbonatite complex is located in eastern Finnish Lapland. The main ore of the carbonatite massif is a regolithic phosphorus ore in the weathered crust. Large-scale geophysical measurements and diamond drillings have also established several niobium showings within the magmatic carbonatites. Owing to the complicated geology of the massif, the niobium showings occur as irregular zones o r areas displaying complicated structure, texture, mineralogy and geochemistry (Vartiainen and Paarma , 1979; Vartiainen , 1980). The tonnages in areas such as this are large but the grades in-situ are low . The most intensely studied niobium showing is the Kaulusrova area.The exploitation of these showings depends on the feasibility of applying a sorting technique to upgrade the feed and to minimize the amount of material to be treated in the concentration plant. These possibilities o n the Kaulusrova area have been viewed by a detailed geological and X-MET an analyzing study."

Jan 1, 1985

By Sylvain Castonguay, Sylvain Pilon

"Operator competency is an important factor in the safe and successful operation of today’s complex processes. Competent process unit operators deliver superior performance and results. In greenfield projects, operator competency is particularly critical, as the lack of specific operations experience must be offset with proven practical knowledge and skills to avoid mistakes that can cost millions in terms of start-up delays, production losses and equipment damage. It is, therefore, important to know precisely what competencies are required for a project or site, and what any gaps in operator competency need to be addressed and improved. The success of plant commissioning, start-up and sustainable operations is directly tied to operator competency. The significant investments required for new projects, the exploitation of more challenging ore bodies, and the increasing complexity of plant operations have placed renewed emphasis on the need for competent operators. Furthermore, many large capital projects are being developed in remote regions, often with ties to the delivery of social benefits for the local population in terms of jobs, training and other development opportunities. While automation and processing technologies have helped do more with less, indicators now point to a bottleneck in human performance limiting operational results.Automation industry development in managing abnormal situations, including solutions for simulation and operator training, has produced applications to provide customized and flexible training methods. This paper will discuss tools to automate the operator competency process in order to guide trainers to effectively teach, measure, control, provide feedback, and monitor operator skills. Today’s competency management solutions can be effectively applied throughout the course of an operator’s professional life, as a guide to hiring new operators, for developing competencies to support operations, and also to develop and refine best practices and share lessons learned."

Jan 1, 2016

By W. J. Mcgaughey, R. G. McCreary, S. C. Maxwell, R. P. Young

"Seismic tomography is a process for obtaining images or maps of seismic velocity or other seismic properties of a rock mass. Seismic velocity images reveal variation in elastic moduli which, in tum, are related to several properties required in the geological or geomechanical assessment of a rock mass. Seismic velocity is sensitive to lithology, discontinuities, and in situ stress. Spatial or temporal variation of these properties may be indirectly assessed. Tomographic measurements are sensitive to volumes of ground, rather than determinations at points, or along lines or surfaces, as in conventional geological or geomechanical measurements or mappings.Tomography surveys are complementary to conventional measurements as they have the capability to interrogate a substantially larger volume of ground. They are thus useful in discerning trends or patterns in regions between or surrounding conventional ""point"" measurements of lithology, rock quality, stress, or other parameters of interest. Seismic velocity images give broad indications of trends in velocity; their spatial resolution of ground properties is typically on the order of five to ten per cent of the nominal survey dimension.Research in seismic tomography has been carried out for several years, and the capabilities and limitations of the technique in mining environments are beginning to be understood. This report reviews the present capabilities of seismic tomography surveys in mining, emphasizing rock mechanics applications. Six case studies are used as examples to demonstrate the capabilities of the method in assessing lithological variation, density and orientation of discontinuities, and the effects of stress."

Jan 1, 1994

By Mehmet F. Taner

"Abstract - "Les Mines Selbaie" is a large, generally low-grade, polymetallic (Zn, Cu, Ag, Au) "giant" volcanic-associated ore deposit in the Harricana-Turgeon belt, which is part of the northern Abitibi Subprovince of Quebec. Economically recoverable mineralization occurred in three zones: the A1 (open pit), A2, and B Zones (underground). The pre-mining resource was 54.9 Mt, including 8 Mt of sub-economic, locally silver-rich massive pyrite. In the Selbaie region, calc-alkaline andesitic volcanics form the "basement." The Brouillan Volcanic Complex formed within an islandarc setting on this regional basement. Evolution of this complex involved the formation of a felsic magma chamber and the development of a large caldera structure over the Brouillan batholith. Second- order linear and sub-parallel faults and rifts developed as a result of back-arc rifting/extension. The edges of these rifts were feeders for linear felsic volcanism (similar to fissural volcanism). During felsic volcanism, the feeder zones acted as conduits for hydrothermal fluids with associated pervasive potassic alteration. The alteration is characterized both vertically and laterally by well-defined quartz, sericite, K-feldspar and/or, locally, biotite halos, to produce a mushroom-shaped morphology. This K-feldspar alteration is not common in most other volcanic-associated ore deposits. Mafic dikes cut all of the geological units and appear to occupy earlier synvolcanic structures. Regional greenschist- assemblage metamorphism and pervasive deformation affect all units. Thrust faults moved part of the Brouillan batholith and basement units over the Mine Sequence. Although there is no relationship between the earlier mineralizing events and these late thrust faults, the thrust faults probably played an important role in location of ore lenses. Three types of mineralization are present: 1) copper-rich veins and hydraulic breccias; 2) disseminated and stringer, low-grade and high volume zinc-copper mineralization; and 3) finely laminated, massive, locally silver-rich pyrite mineralization within structural basins. At the bottom of these basins and at the contact of welded acid tuff (WAT) units, massive pyrite zones are locally enriched in zinc, and contain the possible vestiges of black smoker-like material. The ore metals were probably derived from leached basement andesitic volcanics in a hydrothermal system powered by one or more heat sources within the Brouillan Volcanic Complex. The Selbaie deposits are mainly characterized by: (1) the presence of small volcano-tectonic subsidence basins, which host chemical sediments and volcaniclastic materials; (2) pervasive potassic alteration; (3) locally high-grade silver mineralization (up to 1-2 kg/t Ag); and (4) the presence of random zones of Pb mineralization. The Selbaie deposits can be closely compared with the copper-rich Murgul deposits, which belong to the eastern Pontides metallogenetic province in Turkey. If conventional classification criteria for the volcanogenic massive sulfide deposits (e.g., Noranda, Mattabi types, and recent subsea floor deposits) are taken into account, the Selbaie deposits still exhibit many differences in terms of alteration assemblages, physical volcanology and some styles of mineralization (low-grade and large volume). Consequently, the "Selbaie" deposits belong to a new sub-type of volcanic-associated sulfide deposit, which may be used in future exploration programs."

Jan 1, 2000

By Å. Partapuoli, M. Henriksson, P. Wikström, J. Worth, G. Adolfsson

The control of AG mills fed by ores with harder and softer components can be challenging due to the sensitivity of the mill to the ratio of hard to soft components. The mills at LKAB’s iron ore operations are generally well controlled, but there are periods when the throughput falls off dramatically, due to a loss of mill filling. As the ore is upgraded in the sorting plant through magnetic separation prior to milling, this presents an opportunity to manipulate the feed blend in advance. In order to assess this opportunity, a fullscale mill charge was dumped and assayed by size to quantify the build-up of competent waste in the mills. This was supplemented by pilot and locked-cycle laboratory tests at a wide range of feed blends in order to facilitate the development of an appropriate multi-component AG mill model. This paper reports the experimental campaign requirements and methodologies, as well as the major outcomes from analysis and modelling exercises using the industrial, pilot and laboratory multi-component data.

Jan 1, 2012

By J. T. Birkholzer, M. Rutenberg, K. -H. Lux, R. Wolters, J. Rutqvist, L. Blanco Martin

In this paper, we present numerical results corresponding to the Thermal Simulation for Drift Emplacement (TSDE) test, conducted in the Asse salt mine (Germany) between 1990 and 1999 to simulate reference repository conditions for spent nuclear fuel in rock salt. This test is of significant relevance for nuclear waste disposal in salt because extensive research and measurement programs were set up for the experiment. In our numerical study, we use two sequential simulators, TOUGH-FLAC and FLAC-TOUGH, and we investigate two-way coupled processes, focusing on thermo-mechanical analyses due to the main effect of heating. The two simulators used have recently been updated and are able to deal with large strains and creep processes. Moreover, specific constitutive relationships and coupling functions for rock salt and crushed salt under repository conditions are available. Within the framework of a benchmark exercise between Lawrence Berkeley National Laboratory and Clausthal University of Technology, the same scenario has been modeled in three dimensions using the two simulators mentioned. The main objective of the current, first stage of the benchmark is to evaluate the capabilities of these two simulators to predict relevant processes under repository conditions for high-level nuclear waste in saliniferous media. The comparison of the numerical predictions between them is very satisfactory, leading to a successful code-to-code verification. The comparison between measurements and numerical results shows that the most important processes are captured by the codes and constitutive models used. However, some differences exist between measurements and numerical results. These differences will be addressed in the next stage of the benchmark exercise, in which a parameter fitting effort will be undertaken. Overall, from the results obtained it can be concluded that TOUGH-FLAC and FLAC-TOUGH have the necessary capabilities to reproduce relevant processes under repository conditions for high-level nuclear waste in saliniferous formations.

Jan 1, 2015

By Guillermo Diaz, Roberto Pérez, René del Villar

"Pulp-froth interface position is a key variable in column operation. In plant practice, it is commonly estimated through a system of three pressure-transducers which allows the calculation of the pulp height. An alternate method based on the measurement of the conductivity profile across the interface has been proposed and successfully tested. Both methods however, present some practical problems related to the assumptions made in the calculation of the pulp height in the former case, and to the response time and the precision of the reading in the latter case.In this paper, the use of the neural network technique for improving the estimation of the pulp-froth interface in flotation columns is discussed. The technique is used with both conductivity-based and three pressure-transducer methods. Results obtained in a 2"" laboratory column and a 12"" pilot scale column are presented. A major obstacle in applying this approach in practise is the training of the artificial neural network. This problem is analyzed here for the conductivity-based method and some solutions are proposed."

Jan 1, 1995