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By J. Huh

Recently, there is growing trend to build the high-rise and install curtain walls. Following this trend, we developed robot for building wall cleaning work, which moves along Built-in guide rail of building. Because it moves attached at building wall for cleaning work, it can be seriously affected by potential threats, like earthquake, strong wind, malfunction, and construction error of built-in guide rail. In order to cope with those threats actively, this paper presents the Fail-Safety system. The building wall cleaning robot consists of two moving system: The Horizontal Moving System which mainly do maintenance work, and The Vertical Climbing System which transport the horizontal moving system floor by floor. We apply the Fail-Safety system to these systems. The Fail-Safety system consists of sensors to detect external situation, and, with information of sensors, give instruction for what to do. This robot system is installed with four kinds of sensors: shock sensor, infrared ray sensor, laser sensor, magnetic sensor. First, shock sensor detects external shock during cleaning work. When shock sensor detects big shock, the robot returns to starting point to inspect how damaged it is. Second, infrared ray sensor detects damage of built-in guide rail. It is to prevent destruction of robot caused by moving along damaged rail. Third, laser sensor gives notice about where obstacle is. It is for robot to avoid crash with obstacle and decrease damage. Fourth, magnetic sensor detects magnetic points, which are installed in rail at regular intervals, and helps robot to find its position, based on location of magnetic points detected. If robot is damaged by external shock and its encoder, which gives information of location to it, is not working, magnetic sensor will give information of robot?s location to robot. And then, robot regulates its velocity depending on position of it, and safely returns to starting point. The Fail-Safety system in this paper is for building wall cleaning robot to sense external threats, and prevent getting worse. Applied to this active protection system, making safe environment of maintenance work is possible for robot system.

Aug 1, 2013

By The Staff

"IntroductionThe difficulties to be overcome in shaft sinking and development at depth are centred at McIntyre in and around No. 12 shaft. Generally they have been due to increasing pressures and temperatures and to changes in geological structure. This paper describes the difficulties and the measures taken to meet them.No. 12 ShaftEarly in 1932 McIntyre decided to sink an internal shaft from the deepest level, the 3875, to explore and develop known veins extending below that horizon. The location selected was a point 1,500 feet south and 1,000 feet east of No. 11 shaft, the main operating shaft through which the men, ore, and most of the materials are handled Shaft and auxiliary equipment we1e laid out for 3,000 feet, that is to 7,000 feet below the surface. The shaft was to be capable of handling 1,500 tons of ore daily from the lowest level, and was to provide ventilation, compressed air, water, and electric power to service all levels.No. 12 is an internal, vertical shaft extending from the 3875 to the 6825 level and bottoming at 7,007 feet. It is a rectangular, four-compartment shaft, 21 ft. 9¾, in. by 6 ft. 3¾ in. outside the timber (Figure 1).There are two hoisting compartments and one airway compartment, each 4 ft. 10¾ in. by 5 ft. ¾ in. inside dimensions, and a combined manway, pipe, and cable compartment 4 ft. ¼ in. by 5 ft. ¾ in. Levels have been established at 150-foot intervals, pump stations and sumps at 1,000-foot intervals, and. there are two loading pockets, one at the 5525 and the other at the 6900 level.The shaft was sunk in two stages. The first stage, consisting of preparation above the 3875 level and sinking to 5585 feet, was completed by March 31st, 1935. The second stage of deepening the shaft from 5,585 to 7,007 feet was started August lst, 1946, and completed three years later."

Jan 1, 1950

By C. R. Hocott

"IntroductionRESEARCH in petroleum production consists primarily in investigations related to the drilling for and recovery of oil. As an organized activity of individual oil companies, production research is now 30 to 35 years old, and the petroleum industry may point with justifiable pride to the achievements of this third of a •century. Emphasis on research has grown through the years until at the present time many of the larger companies operating in the United States •have well-organized production research staffs.In addition to the efforts of the oil companies, significant research and development in petroleum production technology have been performed by oilfield service companies and others. Valuable contributions have been made through fundamental research carried on by the U. S. Bureau of Mines and by various colleges and universities, both in their own programmes and in programmes sponsored by industry, such as those of the American Petroleum Institute. However, the total effort of these groups is small when compared to the sum of the effort devoted to research by the individual .oil companies. In contrast to some industries which conduct the major portion of their research through co-operative, sponsored research at universities or research institutions, research by the petroleum industry is done predominantly by individual company research staffs. These industrial research groups have usually been organized in such a way as to provide liaison and co-ordination with operating technical staffs. In this way, the research groups are kept aware of the major problems confronting the operating departments and, correspondingly, the operating technical people •are able to keep informed on research activity and progress. This type of close contact generally results in prompt testing of research developments in actual operations."

Jan 1, 1953

By J. W. McCammon

CRANGES in construction ideas and the continually rising costs of labour and conventional building materials, particularly since World War II, have prompted widespread investigations into the development and adaptation of new materials to meet the new requirements and to help reduce costs. Lightweight aggregates have been prominent in these investigations. The lightweight aggregates most commonly used today are foamed slag, cinders, pumice, diatomite, exfoliated vermiculite, expanded perlite, and bloated clay or shah. Lightweight aggregates contribute to the building industry in several ways: ( 1) in large structures the reduction in deadweight effected by the use of lightweight materials reduces the amount of reinforcing and structural steel necessary to support the structure; ( 2) the decrease in weight of lightweight blocks makes handling easier and faster; (3) pre-fabricated floor and roof slabs and tilt-up walls of lightweight concrete have become feasible and popular; ( 4) lightweight aggregate concrete has good nailability and is easily channelled; (5) concrete and plaster made with lightweight aggregate have good heat and sound insulation properties.

Jan 1, 1957

By Olli Haavisto, Lauri Koresaar, Navid Khajehzadeh

In recent times sustainable minerals processing is an important topic in research. Sustainable mining is linked with efficient use of energy and human resource in all process stages including beneficiation of the ore. Controlling and optimizing the recovery while preserving the grade of the concentrate is extremely important in flotation plants. This development requires new technological solutions and has given rise to the multitude of application areas for lasers. X-ray Fluorescence (XRF) and Laser-Induced Breakdown Spectroscopy (LIBS) are currently two of the predominant non-contact and direct analysing methods in industry. LIBS and XRF measurement techniques both have high capabilities for measuring elements. LIBS has a very simple and easy-to-implement spectroscopic setup, wider range of elements can be detected with online LIBS and measuring light elements is simpler by LIBS compared with XRF. It is of great interest to extract mineralogical information from the elemental results with no modification on the measurement setup. In order to achieve this, more advanced interpretation of the elemental peaks of LIBS spectra is required. Therefore, the major focus of this research is about measuring mineral concentrations from the elemental lines of LIBS spectra using advanced statistical methods. This accomplishment provides knowledge about mineral concentrations from the real-time assay data of the slurry LIBS analyzer. Consequently, this paper first discusses an analytical method called partial least squares regression leading to rapid mineral identification from the elemental contents of the LIBS technique. Then the technique is employed to analyze the mineral contents quantitatively through the information acquired from an on-stream LIBS slurry analyser. This can lead to many benefits such as rapid control of concentrate quality, enhanced recovery, saving time, energy and manpower.

Jan 1, 2016

By M. Pötsch, A. Kluckner, P. Söllner, W. Schubert

"The in situ block size is a key parameter in the geomechanical characterization of rock masses. It describes the fracturing of the rock mass and thus is a measure for the degradation of the rock mass strength. Several classification systems use the in situ block size. For instance, the Geological Strength Index (GSI) requires the “blockiness” and joint surface condition factor as key input parameters. The “blockiness” has recently been related to the in situ block volume (Cai et al., 2004). Due to the limited information about the internals of a rock mass, it is not possible to determine the in situ block size directly. Currently, the in situ block size is determined by calculations using oversimplified models, vague estimations or, due to the lack of relevant information, it is neglected. As remote measurement systems have become available for rock mass characterization, a more comprehensive record of discontinuities can take place. Measurements can be performed on exposed rock outcrops and in particular on tunnel faces and walls, delivering the location, orientation, spacing and persistence of discontinuities at an arbitrary number and locations. An estimation of the in situ block size at the same level of sophistication is still not available. This paper aims at examining the relationship between visible and measureable information at the rock surface, and the in situ block size. Three-dimensional block model simulations were performed using the block model engine of the distinct element code 3DEC. Initial investigations focussed on the minimally required observation area in order to obtain reliable block size distributions. Based on a representative volume element, a reference distribution of the block area at the observation area for a specific discontinuity system was determined. Subsequently, the size of the observation area was decreased stepwise and each new distribution was compared to the reference distribution. For all analyzed systems, it turned out that the mean block area must be smaller than 1% of the observation area to achieve a reliable block size distribution. Further simulations focussed on discontinuity systems with three non-persistent sets. The results were compared to the formula proposed by Cai et al. (2004). A transformation factor T was introduced which replaces the persistence terms in Cai et al.’s proposed formula. The factor describes the correlation between block volumes generated by persistent and corresponding non-persistent discontinuity sets. The simulations included the variation of the discontinuity set spacing, persistence, and orientation. The mean and additionally the 25%-, 50%- and 75%-quantiles of the block size distribution were analyzed. Examining all values for the transformation factor the distribution can be described by a power function with a negative exponent. The function depends on the persistence only. Finally, the results of random simulations were compared to the analytical formula using the transformation factor. The predicted mean and selected quantiles show a good agreement with the simulation results. It gives a comprehensive picture about the block size distribution in discontinuity systems with three non-persistent sets."

Jan 1, 2015

By R. Holmestad, M. Gazizov, S. Wenner, R. Kaibyshev, J. K. Sunde

"Mechanical properties and microstructure of an Al-4.7Cu-0.74Mg-0.51Si-0.48Mn-0.10Cr-0.09Ti-0.02Fe (wt. %) alloy subjected to various thermomechanical processing (TMP) have been investigated and compared to conventional ageing at 170°C (designated T6). Three TMP routes involving cold deformation of solution treated samples were tested. These were (i) 3%-stretching (T8-3%), (ii) equal-channel angular pressing (ECAP) to true strain (e) of ~1 (T8-1) and (iii) ECAP to e~2 (T8-2), all with subsequent ageing at 170°C for 0-96 h. At peak age conditions, both yield stress, ultimate tensile strength and elongation-to-fracture decreased for the T8-3% state as compared to the T6 condition. Intermediate ECAP (T8-1 and T8-2) lead to significant increase in maximum yield stress, ultimate tensile strength and elongation-to-fracture. The changes in mechanical properties were related to microstructure evolution, encompassing changes in grain sizes, dislocation densities, precipitate morphology and phase fractions, which were characterised using transmission electron microscopy. Relations between TMP, precipitation behavior and contributions to different strengthening mechanisms are evaluated.INTRODUCTION Al-Cu-Mg-Si alloys are widely used as structural materials in aerospace industry due to their attractive combination of high specific strength, good fracture toughness and enhanced creep resistance. These properties are largely due to the formation of a large number of nano-sized metastable precipitates during artificial ageing (Polmear, 2006; Eskin, 2003; Gazizov, Dubina, Zhemchuzhnikova, & Kaibyshev, 2015). The precipitation behaviour in these alloys is complicated and depends among other things on Cu concentration and the Mg:Si ratio (Wolverton, 2001; Chakrabarti, & Laughlin, 2004). In general, the precipitation sequence has been presented in a prior study (Eskin, 2003) as follows:"

Jan 1, 2018

By T. K. Bose

According to the Intergovernmental Panel on Climate Change (IPCC), the average global temperature has risen over the last century. If this trend continues over the next century, the IPCC projects a significant increase in temperature and a rise in sea level. The changes in climate could adversely impact human health, agriculture, water resources and ecosystems. Most national and international agencies have concluded that our use of carbon-rich fuel is responsible for global warming through the greenhouse effect. In the future, the situation may get worse if the increased need for energy in countries like China, India and Brazil is fulfilled by burning fossil fuel. Advanced natural gas-fuelled vehicles have the potential to reduce carbon monoxide and reactive hydrocarbon emissions substantially compared to gasoline vehicles. Further environmental benefits can be realized by using a blend of natural gas and hydrogen. Such an approach will help create an infrastructure for an eventual transition to hydrogen.

Jan 1, 2005

By D. Kovachevich, M. A. Pfeifer

"A t remote locations typical of mines and associated ore processing plants, diesel electric generators are ideally suited for power plants due to their inherent operating flexibility, efficiency and reliability. In recent years rapid escalation in fuel and related transportation costs has made extensive waste heat recovery from generating sets financially attractive to a much greater extent than previously.The paper outlines key considerations during planning and design stages for utilizing the various waste heat sources available to best advantage. Based on two /980 mining projects built in the Canadian Arctic, data is presented on potential operating and capital costs savings. A review of heat balances, engineering flow diagrams and major equipment selections for process and building heating systems utilizing waste heat is included.IntroductionResource projects increasingly occur in remote areas requiring on-site self sufficiency in electrical power generation. For such projects, the low- or medium-speed turbo-charged diesel engine is very often the preferred choice as a prime mover for the generating sets . It is inherently reliable, has good response to load changes and has comparatively high fuel efficiency over a wide load range . From a project execution standpoint, It is capital cost- competitive and procurement lead-time normally ' fits ' within tight schedule constraints. In addition, its potential for waste heat recovery is excellent , particularly in northern climates where space heating requirements are usually substantial, and also where there a re requirements for heat for process and plant services.The high cost of fuel , with add-on transportation costs , provides a major incentive to fully exploit the available waste heat recovery potential o f such installations.As a result of the rapid escalation in the price of petroleum products following major crude oil price increases in 1973 and again in 1978-79, liquid petroleum fuels, having the desirable properties of comparatively high heat content and transportability, are no longer 'cheap' commodities and have become so valuable that industry has widely undertaken serious conservation efforts.Currently, it appears that petroleum cost trends of the 1970s may not continue, at least in the near term, and that we may see somewhat reduced energy costs for a time. In the longer term , and certainly within the life spa n of major projects, however, it is generally believed to be inevitable that these fuels will be increasingly expensive . Energy costs are today a major operating cost for remote minerals processing plants and will remain so for the foreseeable future.In order to meet the economic challenge posed by high energy costs, future projects should be thoughtfully planned from the outset with the goal of minimizing energy requirements and maximizing the use of waste heat recovery to meet such requirements. There is also considerable potential for significant energy savings by retrofitting of existing installations."

Jan 1, 1984

By E. Mataradze

Statistics shows that the majority of accidents with fatal outcome are caused by methane and/or coal dust explosion. This leads to assume that contemporary counter-explosion systems of various designs cannot be considered effective. Considering the growing threat of methane explosion in the coming years along with the development of deeper levels, the improvement of a system for protecting people in underground opening appears urgent. This paper presents the results of the testing of the Automatic System from Methane Explosion in Coal Mines. The protective system consists of: i) a wireless device for the detection of explosions and activation of a protective system, and ii) an absorber with a pyrotechnic device ensuring the discharge of dispersed water. The protective system, at the command of the initiation signal, produces tailored dispersing water mist with droplet sizes in the range of 25?400 ?m along selected tunnel sections.

Aug 1, 2013

By M. E. Coleman, G. Money

Pneumatic Conveying and Process Injection Technologies have been implemented in the metals markets for the last 40 years and have considerably improved the productivity and the performance of many processes. There have been many steps forward in handling technology and this paper seeks to consider those now offered by Clyde Materials Handling who as an established customer-driven solutions provider has turned its attention to supporting the Metals Market. Clyde seeks to utilise its knowledge, expertise and technologies to transform the production processes of its customers, who operate in the ferrous and non-ferrous metals industries.

Jan 1, 2008

By K. Dinh

The Ground Penetrating Radar (GPR) has been studied for a long time as a non-destructive evaluation (NDE) technology for inspection of concrete structures. Currently, the most widely used technique for interpreting GPR data of concrete bridge decks is the one that based on the amplitudes measured at various interfaces such as asphalt-concrete, top rebar, or slab bottom. The assumption behind this technique is that a sound concrete deck should have the same reflection amplitude at these interfaces while any low number would indicate some sign of deterioration. Unfortunately, this assumption is not completely valid in most cases. As a consequence, the reported test results usually do not reflect real condition of concrete bridge decks in question. The main goal of this paper is therefore twofold: (1) to discuss the limitations of the amplitude analysis method, and (2) to propose a new model that interprets GPR data of concrete bridge decks. The model methodology is based on the comparison of GPR A-scans between two inspections, using the so-called correlation analysis. The results, indicated by the correlation coefficients, are then employed to develop a contour map that estimates different levels of deterioration. The model is then implemented to a case study in order to illustrate its methodology.

Aug 1, 2013

By K. Hardy

As part of Inco's $115 million Fluid Bed Roaster SO2 Abatement Project, a new weak acid treatment plant (WATP) was constructed to treat bleed solutions from the Copper Cliff Smelting Complex gas-cleaning circuits. The WATP produces an iron-arsenic co-precipitate, termed "basic ferric arsenate" (BFA), which requires disposal in an environmentally acceptable manner. Following analysis of many potential options, the short-listed disposal alternatives were: A) Co-disposal of the BFA?gypsum sludge with rock tailings, a portion of which would be used in mine backfill, with the remainder being sent to the tailings area, and B) Co-disposal of BFA?gypsum sludge with pyrrhotite tailings in the tailings area. Testwork showed that the addition of BFA?gypsum sludge to mine backfill samples increased the uniaxial compressive strength (UCS) of the backfill for most samples, especially those at lower binder content ratios. Extensive analysis was conducted on samples taken from the Copper Cliff tailings area, where BFA?gypsum sludge from Inco's Copper Refining Electrowinning Department has been co-deposited with pyrrhotite tailings since 1990. Pore water samples from these areas contained very low arsenic concentrations, indicating that the arsenic had remained stable in that environment. Ultimately, co-deposition with pyrrhotite tailings was chosen as the preferred option for the disposal of BFA?gypsum sludge from Inco's new WATP.

Jan 1, 2006

By Peter M. Power

A microscopic study was made of a series of simultaneous slag and metal samples taken from a low carbon basic open hearth heat. An attempt was made to identify the various micro-constituents found. As the various impurities in the bath are oxidized, the metal structure changes from that of high-phosphorus white cast iron to that of low.-carbon steel. A detailed study of phosphorus distribution is included. The acid run-off slag has an .acicular orthosilicate structure which changes on 'shape-up' to a very basic tri-calcium silicate and calciuim ferrite structure. Many unidentified minor constituents are present in the slags. Though metallography will never replace chemic.al analysis of the bath, the microsopic study of polished slags has some promise of being useful in slag control work.

Jan 1, 1956

By The Staff

"IntroductionThe published information concerning treatment of uranium ores has been very limited as far as Canadian ores are concerned. Such information has dealt mainly with refining processes for concentrates or rich ores, designed to recover radium rather than uranium; these methods could not be economically applied to low-grade ores.The purpose of this paper is to describe treatment possibilities for some of the .ores that have been treated at the Mines Branch, and .to show how the character of these ores influences methods and results.What is a Uranium Ore?Prospecting for uranium has been extremely active during the past two years and a great many occurrences of radioactive minerals have been recorded. Such prospecting has been based to a large extent on the use of the Geiger counter in the fie1d. This equipment is an invaluable aid when the results are properly interpreted.Most definitely, indications of high radioactivity do not always prove the presence of a valuable orebody. First we have to determine:(1) Is the radioactivity due to uranium or to thorium. There is no immediate market for thorium.(2) Can the uranium in the ore be economically recovered.Chemical analysis is the most exact method of determining uranium content, but a fair estimate of the uranium, and also of the thorium, content can be made from the difference in gamma and beta activity. The Mines Branch guards against misinterpretation by determining both beta and gamma activities and, if more than a minor amount of thorium is indicated, then a Chemical analysis is made."

Jan 1, 1950

By E. Herrera Alarcón, L. Mariscal Samaniego

The Teniente Converter (wet charge type) was commissioned in august 1995 and was designed to smelt 744 tpd (metric tons per day) of dry copper concentrates. Its products are white metal (73% Cu) that is sent to the Peirce Smith converters, slag that is cleaned in Reverberatory Furnaces and the process gases that are sent to the Sulfuric Acid Plant. Since its start up, the Teniente Converter smelting capacity was increased 1.6 times, from 800 tpd to 1,280 tpd using 33% oxygen-enriched air, and reaching an operative availability of 97%. By the other hand its campaigns have reached a record duration of 530 days without hot patching tuyeres and a partial refractory lining repair in the last four campaigns. This paper describes the most relevant improvements, as well as the strategies that had been used to reach these achievements.

Jan 1, 2007

By T. Robson

"A multi-seam underground mining operation employing mechanized room-and-pillar methods provides 35 per cent of Smoky River's annual ROM coal production (2 million tonnes) from the Smoky River coal field. Surface mines provide the balance. Tectonic activity, which has resulted in deformed coal seams and a rugged relief to the area, has provided natural boundaries to discrete mining areas. Coal transportation to the central preparation plant incorporates a 3 km long underground conveying system. The company is committed to efficient resource recovery and a safe and healthy working environment. Introduction The Smoky River Coal operations (SRC) are centered in the Smoky River coal field located in west central Alberta, some 360 km west of Edmonton and 20 km from the Town of Grande Cache (Fig. 1). Combined mining operations produce 2 million tonnes per year run-of-mine coal from which 1.65 million tonnes of high quality, low volatile, coking coal are obtained. The underground mining operation, employing mechanized room-and-pillar methods, provides 35 per cent of SRC's annual ROM coal production (2 million tonnes). Surface mines provide the balance. Tectonic activity has resulted in deformed coal seams and a rugged relief in the area. This has provided natural boundaries to discrete mining areas. Background Exploration of the Smoky River coal field took place over four decades commencing in 1926. McIntyre Mines Limited (parent to Smoky River Coal Ltd.}, commenced development of the property in 1968 having secured a long-term contract for the delivery of coal to Japan. Production of underground coal at Smoky River commenced toward the end of 1969 and has been continuous on the property since that time. Originally, two underground mines were opened. Original planning envisaged the use of room-and-pillar techniques to develop blocks of coal for subsequent extraction by longwall retreat mining. Following initial development, two longwall units were established, the first in November 1970 in No. 5 Mine and the second in February 1971 in No. 2 Mine. Difficulties were experienced on both units, and production commitments could not be achieved. The longwalls were discontinued, and mechanized room-and-pillar was subsequently used for all underground mining."

Jan 1, 1985

By P. K. Kaiser, C. D. Martin, F. Amann

"This article focuses on the uniaxial compressive strength (UCS) of homogeneous and heterogeneous rocks. Critical factors impacting the UCS of rocks are reviewed and then separate assessments of UCS data from homogeneous and heterogeneous rocks are presented. The variability (coefficient of variation) of UCS test results for homogeneous rocks is found to be generally <25% while for heterogeneous rocks the variability is >35%. Failure mode variation is found to be the cause of the variability of UCS test results in heterogeneous rocks. Empirical engineering design methods that use UCS as an input parameter are discussed and suggestions are provided for selecting appropriate UCS values.INTRODUCTIONThe UCS is one of the most commonly used rock engineering parameters whether for rock mass classification or for strength determination. The mean UCS and its variability are often assumed to represent a reliable rock material property. For the reasons discussed in this article, UCS is rarely representative of the intact rock UCS. The UCS test simply records the collapse load during uniaxial loading of a cylindrical specimen. As suggested by many, the UCS is an index rather than a unique engineering parameter. The UCS is thus a proxy for rock strength which depends on the loading rate (e.g., Bieniawski 1967), specimen geometry (e.g., Hudson et al., 1971), specimen size (e.g., Bieniawski 1968), and many other factors. Furthermore, the UCS is not the same as the Hoek-Brown strength criterion parameter sci.There are differences in opinion on what is commonly considered to be ‘intact rock’. When sampling ‘intact’ pieces of core from drillholes crossing blocks of rock bound by block forming discontinuities, samples will be ‘intact’ but some samples will be veined, others will be damaged, and others will be neither. According to Hoek (1983), intact rock pieces are “the unfractured blocks occurring between structural discontinuities in a typical rock mass” and the sci parameter for intact rock is determined using the fitting procedure proposed by Hoek and Brown (1997) based on the data requirements outlined by Hoek (1983). Studies (e.g., Bewick and Kaiser 2014; Kaiser and Kim 2014) have shown that independently determined UCS and sci values for the same rock type are not equivalent. Thus, UCS data cannot be used as a replacement for sci."

Jan 1, 2015

By P. Coursol

The Noranda Reactor Process (NRP) has been in operation now for more than 30 years and this mature process has attained a high level of performance. The NRP at the Home Smelter of Xstrata Copper treats a wide range of feed materials and a thorough knowledge of both process control and smelting physico-chemistry has been beneficial to help meet the required plant flexibility. In this regard, some level of predictive knowledge related to slag chemistry, in particular, the liquid and solid phases such as spinels or olivines, has been found to be beneficial. In the last decade or so, the availability of commercial thermodynamic modeling packages, such as Factsage1m have been utilized with advantage to help the plant optimize slag chemistry and minimize problems from difficult slags, for example, those the could arise from undue feed variability. This paper illustrates the application of this software in examining a range of operating parameters such as: %Fe in product matte, the %Fe/%Si02 ratio in the slag, the levels of minor slag components including CaO, Ah03, ZnO, and MgO, and the level of oxygen enrichment on the operating conditions of the NRP. The slag composition boundaries at the conditions affecting magnetite control and solid magnetite/other precipitated solid phases, as well the conditions influencing the slag liquidus ranges of NRP slags are also discussed with respect to the overall process chemistry.

Jan 1, 2007

By Nick Vayenas, Ming Cai, Hongbin Zhang Lorrie Fava, Enrique Acuña

"A hybrid methodology is proposed to improve the accuracy of Diesel Particulate Matter (DPM) concentrations simulated in a ventilation network model by using Computational Fluid Dynamics (CFD). DPM, as a primary concern for underground hard-rock mines, has been studied in two dominant numerical models, ventilation network solvers and computational fluid dynamics. Ventilation network solvers are efficient, but they are not able to provide three-dimensional DPM concentration contours and only accept area-average DPM data as input. CFD simulations are time-consuming, but generating DPM concentration results with high accuracy. Besides, both monitoring points and planes can be created in a CFD model, which can take both point data and area-average DPM data as input. The hybrid methodology is intended to combine the advantages of the two by using the CFD results to update the network model results at key locations. A field study was conducted in a dead-end heading in an underground gold mine in the United States. Real-time DPM monitors were used to collect data. A CFD model and a network model were built for the experiment area. The CFD model was calibrated to the experimental data. In the study presented here, results from a calibrated CFD model are converted to equivalent diesel emission rates in the ventilation network model at a shared outlet. The hybrid methodology is used to provide better input for the network model. INTRODUCTION Mine ventilation system is one of the most important parts for an underground mine. It not only provides fresh air to the personnel but also helps clear the contaminants generated from the diesel-powered equipment. For most underground metal and non-metal mines, diesel particulate matter is the main contaminant. It is also the focus of this paper."

Jan 1, 2019