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By Edward Kline

A review and synthesis of literature pertaining to biological consequences of submarine mine-tailings disposal (STD) was conducted. STD can result in massive sea floor sediment deposition. STD may also increase suspended sediment, trace metals, and residual milling reagents in receiving waters. These perturbations, which are highly site dependent, invariably smother benthic organisms, and could potentially affect or alter fish, plankton, and benthos through acute and chronic toxicity, bioaccumulation, behavioral changes, smothering, derived secondary effects, and habitat alteration. Much of the available information concerning STD is unpublished and limited to a restricted number of sites. From this information and related research, it appears that benthic smothering is the only major consequence of a properly designed STD system. There have been cases of metal bioaccumulation due to inadequate preliminary evaluation, Also, shallow water habitat alteration has resulted from STD. Reductions in biological production are likely due to benthic smothering. The rate of ecological recovery after termination of an STD operation varies and is difficult to assess, The consequences of STD are site specific. Additional research is needed concerning possible consequences of milling reagents and the broad implications of benthic smothering. Also, methodologies are needed to allow better prediction of benthic recolonization and ecological implications of metal bioaccumulation.

Jan 1, 1994

By K. Woo

The increasing move to block cave mining methods (including sublevel and panel caving) to access deeper and lower grade ore deposits as near surface sources become exhausted raises questions as to the extent and magnitudes of caving-induced subsidence as it may affect strain-sensitive infrastructure on surface. Predicting these surface deformations is difficult as they tend to be discontinuous and asymmetric due to large movements around the cave controlled by geologic structures, rock mass heterogeneity and topographic effects. Of further impediment is the sparse number of case histories available, in which actual subsidence measurements are reported to provide guidance and empirical constraints for subsidence calculations. This study reports the development of an exhaustive and comprehensive database of available (i.e. public domain) subsidence data from block cave mining operations from around the world.

May 1, 2009

By I. A. Mutemererwa

This paper investigates the role of vertical integration between chrome ore mines and ferrochromium smelters in the location of ferrochromium production capacity in South Africa and Zimbabwe. Vertical integration is important in understanding the increasing competitive position of these two countries as observations show that an increasingly larger share of the global market has been coming from integrated producers. The paper argues that the increased vertical integration between mines and smelters in South Africa and Zimbabwe has led to a lower cost of chrome ore as an input compared with other producers. Underlying this hypothesis is the basic tenet that, more likely than not, production will take place where the costs are lowest. The paper concentrates on high carbon ferrochromium (HCFC) production in market economy countries (MEC). Using an ordinary least squares model, the study tests the relationship between low chrome ore costs and vertical integration shows a statistically significant relationship. These findings partially support the view that the control of sources of chrome ore is a major source of competitiveness. Keywords: competitiveness, ferrochromium (ferrochrome), ordinary least squares, dummy variables, vertical integration, southern Africa.

Jan 1, 2000

By Paul F. Gnirk, Ralph A. Wagner, Joe L. Ratigan

This thermomechanical analysis used the finite element method to investigate the behavior of crushed salt backfill in a waste disposal room situated in a salt dome repository. The first of two objectives was to determine the transient temperature rise and degree of thermomechanical consolidation that occur in the backfill as a function of drillhole depths. The second objective involved the evaluation of closure due to salt creep of unlined emplacement drillholes and the determination of pressure on steel sleeve liners in the drillholes should liners become necessary for canister retrieval. The retrievability period was considered to extend for 25 years after waste emplacement. The canisters were assumed to contain ten-year old high level waste with a thermal output of 4.3 kW at the time of emplacement.

Jan 1, 1981

By Djavid Mohammad

Over the next several years, the storage capacity of the Metropolitan Water Reclamation District of Greater Chicago?s Tunnel and Reservoir Plan will be increased by 14.8 billion gallons through the addition of two large off-line reservoirs: the McCook and Thornton Reservoirs. The Thornton Reservoir will be constructed at the terminus of Calumet TARP System. The constructed TARP system will be connected to the Thornton Reservoir via connecting tunnels and gates systems. The connecting tunnels will comprise of: an upgradient transition tunnel, steel lined bifurcated tunnel for conveyance and control of flow, downdradient transition tunnel, and energy diffuser at tunnel portal. A large, approximately 250-foot-long, 69-foot-wide, and 40-foot-high, rock cavern will be excavated at an average depth of 320 feet to house the bifurcated tunnel system and associated six large control gates, each 12.5-ft by 28-ft wheel gate. Presented in this article are discussions about the TARP system, the Connecting Tunnels and gates Project, regional rock conditions, evaluation of reservoir?s wall stability for evaluation of tunnel penetration, and design challenges facing during design of the: rock cavern hosting the bifurcated tunnel system and gates and associated tunnels and shaft.

Jan 1, 2008

By Andreas Hucke

For the roadway design in the German hard coal mining industry, an advanced combined planning system has been applied during the past 20 years. The German mining industry is working with single entry roadways system. After first longwall passage the roadways will be stabilised with side wall building material packages. Later this roadway will be used again for the second retreating longwall. The intention of the implementation of several different design methods for the planning of the roadways is to enhance the reliability of the results. On one hand the planning system uses numerical simulation and physical modelling in addition to analytical and empirical methods. On the other hand in-situ monitoring and analysis during the roadway development will be used to verify and calibrate the numerical and physical models. Especially before the implementation of new support elements in underground, this system is suitable and reasonable because the new support elements will be tested in the physical and numerical simulation prior to cost intensive underground tests. The interaction between the numerical and physical modelling in comparison with underground monitoring and analysis during development and the later use of roadways will be shown with some examples. The first example shows a rock bolted rectangular roadway which will be mined at both sides of the roadway. Different support and roadway building material package systems are investigated under various stress conditions. The results are utilised to optimise the roadway support and the roadway side package systems. The influence of different points in time of the installation of several support elements in a combined arch and bolted roadway is shown as another example. Two different types of support systems are compared within the physical models. These models are used as a base for ongoing numerical analysis and simulation to find out the ideal point of time to assemble the different support elements. The last example handles the influence of slickensides in the roof of arch shaped roadway on their stability. Different slickenside positions and densities are investigated and classified.

Jan 1, 2006

By T. Hidayat, D. Shishin, S. Sineva, M. Shevchenko

The effects of the slagging components Al2O3, CaO and MgO on the thermodynamics and phase equilibria of the gas/slag/matte system with major elements “Cu2O”-“FeO”-SiO2-S are characterised using an integrated experimental and thermodynamic modelling approach. The experimental technique included high-temperature equilibration experiments using a spinel substrate in controlled gas atmosphere (CO/CO2/SO2/Ar), quenching of the sample and subsequent measurement of the compositions of equilibrium phases with Electron Probe X-ray Microanalysis (EPMA). Thermodynamic modelling is undertaken using the computer system FactSage. In previous experimental studies on this system, the separate effects of Al2O3, CaO and MgO were determined. In the present investigation, the combined effects of these additional components are investigated at 1200oC and P(SO2) = 0.25 atm and a range of P(O2)’s. Special attention is paid to ensuring chemical equilibrium is achieved in each case, for this reason possible kinetic factors are systematically analysed. The results obtained are presented in the form of graphs showing the compositions of matte and slag phases as functions of copper concentration (matte grade). The new experimental data are used for the improvement of the thermodynamic database for multicomponent copper-containing systems. The effects of the slagging elements on this multicomponent system will be presented in the paper. INTRODUCTION Whilst Fe-O-Si form the principal components of copper smelting and refining slags, additional impurities are present in industrial practice typically at 2–5 wt.% Al2O3, 1–4 wt.% CaO and 1–2 wt.% MgO levels (Davenport, King, Schlesinger, & Biswas, 2002). These elements are introduced into the slag as impurities in concentrates and other feedstocks, in fluxes added to the process and in refractory materials. Understanding, and accurate description, of the changes that take place in the smelting process in the presence of these additional elements is of major importance to the optimization of industrial operations. Although experimental data are available on slag/copper matte equilibria, further work is needed to accurately characterise the influence of Al2O3, CaO and MgO on phase equilibria and elemental distributions of elements in gas/slag/matte systems. The individual effects of the Al2O3, CaO and MgO slagging components on equilibrium phase assemblages under selected conditions have been quantified in a recent series of studies on the Cu–Fe–O–S–Si-(Al, Ca, Mg) gas-slag-matte-metal system (Fallah- Mehrjardi, Hayes, & Jak, 2018; Fallah-Mehrjardi, Hidayat, Hayes, & Jak, 2017a, 2017b; Hidayat, Fallah-Mehrjardi, Hayes, & Jak, 2018a, 2018b; Jak et al., 2016; D. Shishin, Decterov, & Jak, 2018; Denis Shishin, Hayes, & Jak, 2018). Since, thermodynamically, the condensed phases do not behave ideally, it is to be expected that the effects of individual elements may not be additive, and the additional interactions between the Al2O3, CaO and MgO slagging components will also have to be taken into account. These additional effects are expected to be smaller than those of the individual components, so higher accuracy is needed. The present paper describes analysis of the precision and accuracy of the experimental technique on multi-component, multi-phase equilibria in these systems to enable the combined effects of Al2O3 + CaO + MgO on slag/matte/spinel equilibria, i.e. for high Fe/SiO2, to be accurately measured. The effects of Al2O3, CaO and MgO on the gas - slag - matte are analysed using a thermodynamic modelling approach with the computer package FactSage.

Jan 1, 2019

By J A. Rabe, PAP Fouche, K O?Neill

Two of the most important issues mines have to deal with are tracking the ore mined from pit to plant and to test the efficiency of beneficiation equipment. Kumba Resources and Saco Systems are working together at moment to develop a RFID tracer system to help address these issues. This paper will focus on the tracking of ore from pit to plant. The main advantages for ore tracking is to ensure plant feed blending and dilution according to plan. The RFID tracer system works on the basis of a tracer that physically simulates the ore properties and radio frequency technology that facilitates communication with the tracer and allowing information to be stored on the tracer. This paper tends to indicate the progress on the application of RFID tracer technology in the minerals processing environment as tested at Kumba Resources so far. It is concluded that the system has great potential, but some important problems remain

Jan 1, 2005

By Innes J. A

The structural variations occurring in pellets of finely divided mixtures of iron ore and coke breeze, metallized by firing at elevated temperatures, have been examined microscopically. For any given pellet composition, time and temperature are the two most important factors in determining the development of the bonding processes.INTRODUCTIONThe success of sintering and pelletizing processes in the agglomeration of fine iron ores for blast furnace use has brought about rapid changes in thinking relative to methods of preparing furnace burdens. Increases in productivity with the use of sinter emphasize the advantages of a stable, uniformly sized furnace feed. Current practice is to produce a self-fluxing sinter containing most of the lime requirements of the furnace incorporated as a stable medium (Figgis and Charker, 1962). The elimination of fine material from the burden allows greater stack permeability and smoother operation.Sintering and pelletizing of iron ores with or without the incorporation of fluxing compounds has conditioned operators to the extent that it is now considered possible that all components of the burden may eventually be beneficiated in one form or another. Investigations are in hand to improve the quality and sizing of coke, which occupies the major part of the burden volume (Callcott, Innes and Brown, 1961; Innes, Gregory and Worner, 1963). Interest is also being revived in methods of pre-reducing iron ores prior to charging to the furnace (Hansen, Melcher and Fine, 1961). Recent experiments in a small experimental blast furnace (Melcher, 1963) show that charging of semi-metallized pellets can give rise to a production increase of 55 per cent...

Jan 1, 1963

By M Donghi, G Ramage, A Barnes

As the mining landscape continues to transform, the challenge of accessing deeper orebodies quickly and safely is becoming a frequent topic of conversation amongst those in the mining industry. The rapid development of underground mine entries to gain earlier access to deeper orebodies is an ever-present challenge to mine owners and contractors. Overcoming this and providing economical solutions to unlock the value in these deeper deposits is a challenge that should be confronted.In 2013, Redpath Australia Pty Ltd (Redpath) commenced construction of what would be the first of two drifts excavated through the use of a tunnel boring machine (TBM) in Queensland’s Bowen Basin.The excavation and development of the two drifts (declines) was completed as part of a contract for underground mining services between Redpath and Anglo American at the Grosvenor Coal Mine Project in Central Queensland, located approximately 5 km north of the town of Moranbah. Having recently completed the drift development, this paper will extend on the early writings of Donnelly, Ramage and Donghi (2014) and provide detail on the operational achievements, advance rates, threats, opportunities and learnings during the excavation of the two declines: the conveyor (CV) drift and the transport (M&M) drift.CITATION:Ramage, G, Donghi, M and Barnes, A, 2016. Experiences gained through tunnel boring machine decline development, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 695–712 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By George L. Gates

[When clays are mixed with water to -.,tee mud fluids for use in trilling wells for nil and --ac b ;l-,e rotary method the liquid mixtures have certain physical characteristics that vary with the quantity and size of their inherent solid particles. All naturally occurring clays contain variable quantities of particles of different sizes ranging from relatively coarse (sands) through -,.tedium (silt) to fine materials of colloidal dimensions. Tie colloid content is extremely important 2.s a desirable _.'ale constituent of mud fl-z to fit well drilling. ';'it:-out colloids the souk?;,' in a mud fluid wouldr rapidly, end ti-c-and. wall-building qualitites of the' fl,-,id would l ..o r re 1 impaired. Mud .fluid.^ with insufficient quantities of colloids also are lacking in "lubricating" g listen, and it is, to ° min casing in, -)re holes drilled with such fluids.]

Jan 1, 1941

By M. G. Maruma

The effect of the amount of cold reduction and annealing temperature on the evolution of the texture of AISI 441 steel is reported. The steel was cold rolled by 62%, 78%, and 82%, followed by isothermal annealing of each sample at 900°C, 950°C, and 1025°C for 3 minutes. The crystallographic texture was determined by Phillips X?Pert PROMPD texture diffractrometer. Microstructures were characterized using optical microscopy and scanning electron microscopy (SEM).The results show that sample that received 78% cold reduction and annealing at 1025°C presented the highest Rm-value and lowest ?R-value, which would enhance its deep-drawing capability. In addition, this sample showed the highest intensity of shifted ?-fibre, notably {554}<225> and {334}<483>. It can therefore be concluded that the ?-fibre, which favours deep drawing, is optimal after 78% cold reduction and annealing at 1025°C.

Jan 1, 2013

By L. V. Clark, Arthur La Motte

"INTRODUCTION The U. S. Bureau of Mines in 1930 and 1931 made a study of the properties and characteristics of liquid-oxygen explosives (L.O.X.) at the request of one of the largest users, in order to determine and eliminate the hazards attending its use.This report deals with the examination of absorbents for L.O.X. to (1) determine their most desirable and most undesirable characteristics, (2) to find ways and means of desensitizing absorbents to mechanical shock, and (3) to determine the effect that such desensitization of absorbents has on the explosive Characteristics of L.O.X.ABSORBENT MATERIALS The absorbent used in driving the Simplon Tunnel, the earliest project in which L.O.X. was used, was composed of crude petroleum, soot, and kieselguhr. During the World War, powdered cork, soot, sawdust, powdered straw, or other similar powdered materials were mentioned in the German military instructions for use of ""liquid air"" explosives. At that time the common types of absorbent, materials were compounded ones containing the above ingredients as well as kieselguhr, paraffin, gas oils, charcoal, bituminous coal, etc.Kuryla and Clevenger4 investigated absorbents of the above type and made the following statement concerning them:"

Apr 1, 1932

The individual or company director who ignores his or her obligations under the Resource Management Act 1991 and under the proposed hazardous substances legislation, ignores them at their peril. Two recent cases in Canada and the United Kingdom concerning environmental offences under similar legislation illustrate the risks well.

Jan 1, 1993

By Brad R. Blair

This paper will review impacts on longwall design and ground stability assessment due to advances in mine automation and sensing technology. Several new approaches to the prediction and monitoring of longwall panel and gateroad stability have recently become mature, and are ready for application in problematic ground control situations. These methods are revealing significant detail regarding deformation and failure mechanics of critical underground structures. Examples of how these technologies have worked successfully will be given, and applications for the use of these tools for cost-effective engineering design and monitoring will be suggested.

Jan 1, 1996

By Shinji Sassa, Naoki Takahashi, Eiji Kohama, Wakaki Tsuda, Hidenori Takahashi, Ikuo Towhata, Yoshiyuki Morikawa

"Abstract Deep mixing method has been employed increasingly in recent years as a countermeasure against subsoil liquefaction. Column-type solidification, however, has been thought to have little effect as a liquefaction countermeasure, because the shear deformation of unimproved soil between the columns cannot be reduced. In recent years, experimental results have been reported that imply that solidified columns can reduce the shear deformation of unimproved soil around them. A new arrangement has been proposed to mitigate lateral flow induced by liquefaction. In this study, a series of dynamic centrifuge model tests was conducted to verify the lateral flow resistance of stabilized columns. The results indicate that stabilized columns can reduce the lateral flow of liquefied ground if the column displacement and the column head rotation are restricted. This paper concludes that it is important to restrict the displacement and the rotation of the column head by surface improvement to mitigate the lateral flow of liquefied ground.INTRODUCTIONDeep mixing method has been employed increasingly in recent years as a countermeasure against subsoil liquefaction. The solidified body formed by the deep mixing method is usually block or lattice shape, composed of solidified columns that overlap each other horizontally. Lattice-type solidification has been shown to be effective as a liquefaction countermeasure despite the presence of unimproved soil inside the lattice wall, because the shear deformation of the interior soil is restrained by the wall (Suzuki et al., 1989). On the other hand, it has been thought that column-type solidification cannot reduce shear deformation of unimproved soil around columns, because the displacement of a solidified column is less restricted than that of a lattice wall. Column-type solidification has been reported to have little effect as a liquefaction countermeasure, but to be superior in terms of construction cost and applicability around existing underground structures (Koga et al., 1986). However, there are experimental results implying that solidified columns have reduced the shear deformation of unimproved soil and mitigated its liquefaction (Yasuda et al., 2003; Tanaka et al., 2003). Yamamoto et al. (2006) conducted dynamic analyses of ground improved with lattice- and column-type solidification. Their results showed that column-type solidification with an improvement ratio of more than 35% reduces excess pore water pressure generated by earthquakes. Furthermore, the new column arrangement shown in Figure 1(a) has been proposed to mitigate lateral flow induced by liquefaction. It was developed and has been verified using dynamic model testing in a 1 g field (Takahashi et al., 2010a; 2010b; 2013; Towhata et al., 2010). The stabilized columns in this configuration interrupt lateral flow in any direction, unlike those placed in square and triangular arrangements."

Jan 1, 2014

By Hamid Mahmoudabadi

In the present paper, the performance of four approaches based on neural networks and geostatistical method for grade estimation are compared and analyzed their performance to find a proper method. Four methods, Multi Layer Perceptron neural network (MLP), Radial Basis Function (RBF), General Regression Neural Network (GRNN) and Ordinary Kriging (OK) are selected for ore grade estimation of variable Fe in an iron deposit located in Iran. For each method, two diagnostic statistics are calculated: Mean square error (MSE) and correlation coefficient. The results show the superiority of the General Regression Neural Network.

Oct 1, 2009

By J. C. Vreugdenburg, B. A. Dippenaar, J. Muller, T. L. de Vries

Iron ore fines are agglomerated to produce sinter, which is an important feed material for blast furnaces worldwide. A model of the iron ore sintering process has been developed with the objective of being representative of the sinter pot test, the standard laboratory process in which the behaviour of specific sinter feed mixtures is evaluated. The model aims to predict sinter quality, including chemical quality and physical strength, as well as key sinter process performance parameters such as production rate and fuel consumption rate. The model uses the finite difference method (FDM) to solve heat and mass distributions within the sinter pot over the height and time dimensions. This model can further be used for establishing empirical relationships between modelled parameters and measured sinter properties. Inputs into the model include the feed material physical properties, chemical compositions, and boundary conditions. Submodels describe relationships between applied pressure differential and gas flow rate through the bed of granulated fine ore particles, combustion of carbonaceous material, calcination of fluxes, evaporation and condensation of water, and melting and solidification. The model was applied to typical sinter test conditions to illustrate the results predicted, and to test sensitivities to parameters such as feed void fraction, feed coke percentage, and the fraction of combustion heat transferred to the gas phase. A model validation and improvement study should follow, ensuring sinter test results are free from experimental errors by conducting repeated tests.

Jan 1, 2015

By James W. Reil

A test series of small, precisely-controlled and thoroughly-monitored production blasts was conducted at two quarries. In each series, all variables except delay were kept constant, as much as practically possible. The first aim of the study was to determine the effect of local geology on ground vibration. The second aim was to test several hypotheses relating the effect of millisecond delay intervals to fragmentation and ground vibration. A resonant frequency of ground vibration was shown to be related to the thickness of the overburden, in accord with a model proposed by Gupta (1961). Since the overburden geology creating this resonant vibration cannot usually be changed, two methods were tested to choose delays such that blast vibrations would destructively interfere. These were shown to be effective in modifying both the peak particle velocity and response spectra of ground vibration. The delay interval chosen also affects fragmentation, primarily in massive rock, with an optimum relief between holes of 2 ms/ft. Strain gage records indicate a possible mechanism consistent with this information.

Jan 1, 1985

By Pervez Patel, Martin G. Frohberg, Demetrios Papamantellos

Model experiments were carried out on the mass transfer of iodine between n-hexane and a 4 2 X 10-3 M aqueous sodium hydroxide solution. The influence of mechanical stirring by means of small gas bubbles (ca. 0.01 ml in volume) on mass transfer was examined in independent experiments. The results were described with the help of the penetration theory and in the case of bubble stirring with the help of a mathematical model based on this theory. S LAG-METAL reactions, especially those in steel-making processes, often occur under conditions where gas is evolved in the form of bubbles that break through the slag-metal interface. It is known that stirring by means of bubbles increases the mass transfer coefficient, but there has been very little quantitative work done in this field. Because of the difficulties that attach to experimental work at high temperatures this study was confined to model experiments at room temperature. EXPERIMENTAL APPARATUS The transport of iodine from an n-hexane layer into a weak sodium hydroxide solution was studied a) with stirring by means of bubbles and b) with mechanical stirring. The apparatus for the experiments with bubbles consisted of the cell, two Dreschel bottles filled with hexane in order to saturate the nitrogen flow, one flow meter, and a nitrogen gas cylinder fitted with a fine-regulating valve. Fig. 1 shows the cell consisting of a glass cylinder 33 cm in height with an overall diameter of 7.5 cm embedded in a copper flange. The flange is connected to a Plexiglas plate and to the gas inlet. The Plexiglas plate has holes of 0.2 mm diam bored into it which are spaced 1 cm from each other. For the experiments with mechanical stirring the bottom of the cell was sealed off by a Plexiglas plate. The upper layer was stirred by means of a glass stir-rer and the bottom layer with the help of a magnetic stirrer in a counter rotatory direction. Both stirrer speeds could be varied continuously. EXPERIMENTAL PROCEDURE Iodine dissolves in n-hexane producing a stable violet color thus enabling the iodine concentration in

Jan 1, 1970