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By P Ireland, S Mitra, G Evans, A Wang, M M. Hoque

This work presents an experimental study of flow dynamics in a bubble column system (crosssection: 100 mm × 100 mm) using a non-intrusive optical technique with targeted application in a novel REFLUX™ Flotation Cell. The study had two aims – measurement of the bubble size distribution (BSD) and local energy dissipation rate in the system due to bubble motions over a low range of gas flux varied from 0.02 to 0.08 cm/s without impairing the visibility of the system. A central bubble plume was generated by injecting compressed air through a sintered glass distributor in quiescent liquid. Highspeed shadowgraphy imaging was performed to determine the BSD in the presence of surfactant (Sodium Dodecyl Sulfate (SDS) concentration ~ 10 ppm). The BSD exhibited a unimodal shape at different locations of the column for all gas flux cases. A non-intrusive particle image velocimetry (PIV) technique was used to quantify the flow field generated by the bubble motions, which was used to estimate the local energy dissipation rate. The local energy dissipation rate exhibited an increasing power-law dependency on the gas flux.

Aug 24, 2022

Different mineral structures can act as mineral reservoirs for the immobilisation of toxic compounds. In the paper different mineral structures will be explained and their potential for incorporation of heavy metals and anions will be shown. The following structures will be explained (P÷llmann, 2007):apatites (incorporation of heavy metals, silicate apatites);ettringites (fixation of oxo-anions);layered double hydroxides (fixation of heavy metals, fixation of anions, fixation of organics, sorption materials); andmanganese oxides. Different possibilities of solid solution and incorporation in crystal structures will be explained and advantages of stable minerals be proved using experiences with real toxic wastes. In the process of thermal treatment the formation of primary mineral reservoirs will be shown. The precursor phases (similar to well known cement minerals) react in contact with water to form secondary mineral reservoirs (cement hydration mineral products). The formation condition of primary and secondary mineral reservoirs and their stabilities and incorporation possibilities will be shown. Examples for incorporation of various elements are given. Application for water clarification will be outlined.

Jan 1, 2008

By Hunefeld R

In the field of mining engineering, design and planning are complex tasks, which require the knowledge of various engineering disciplines. GRUBE (Graphisch-RechnerUnterstiitzter BergwerksEntwurf) is a modular databased program system, which offers computer aid for all mining departments using a 3D CAD software as the user interface. Despite the data quantity and complexity, specific and uniform working conditions have to be applied to the planning of technical equipment of a pit. With the application of 3D graphics, complex data stores and their interrelations become 'palpable' for the user by suitable visualisation. GRUBE-M forms the mechanical operations module of GRUBE, in which underground locations displayed as three-dimensional graphic models are `equipped' interactively. Planning alternatives can be created and compared quickly in terms of technical calculations and economical analysis.

Jan 1, 1995

By Stone AM, Romensky G

The requirement for economic operation of unit trains carrying bulk materials has dictated that rapid and accurate bulk loading methods be provided. The train loading station at Phosphate Hill, built for Queensland Phosphate Ltd. to load rock phosphate, provides this facility and whilst the concept used is not unique, it contains a number of novel features that are considered to advance the "state of the art'' in this field. This paper briefly reviews some alternative concepts evaluated, and describes the design and operation of the scheme ultimately selected as being most appropriate to the project requirements. it is one which utilises a variable speed belt feeder whose speed is controlled in proportion to the weight rate of material moving on the belt as measured against a set point

Jan 1, 1978

By Brzezniak W

Conversion to trolley assist is a means of minimizing diesel fuel consumption, which in many mining situations offers a rapid payback of capital investment plus the inherent flexi- bility and maneuverability of truck shovel op- eration. Whendiesel electric truck shovel mining opera- tion with trolley assist is compared to alter- native mining methods such as conveyor systems, the trolley assist system can be easily justi- fied in terms of return on investment, payback and increased productivity. A review of present technology, performance requirements and past experience in the min- ing industry has led to the development of a trolley assist system for diesel electric haulage trucks which, is proven in the mining environment, offers significant reduction in fuel consumption and increased productivity.

Jan 1, 1981

In North-West Nelson the Riwaka Complex, a linear basic intrusive complex, is exposed for approximately 45 kilometres. Some 500 kilometres south, across the Alpine Fault, a linear zone of similar but less well known basic intrusives that may be correlatives of the Riwaka Complex is exposed discontinuously for about 80 kilometres. The Complex was emplaced at several centers along a major tensional fracture zone that developed in upper Carboniferous to Lower Permian time. This fracture zone probably formed in response to the development of a west dipping subduction zone that gave rise to the Permian volcanic arcs in east Nelson and western Southland. The Riwaka Complex contains three rock suites. The Fractionation Suite, characterized by cyclic mineral layering and small scale cumulus banding is the largest and is divided into the Ultramafic, Hornblende and Plagioclase Series, each of which is subdivided into several units. The Cumulus Gabbros represent a restricted but important suite of unusual composition, while the third suite is the late phase Diorite Suite.

Jan 1, 1980

Flat jack stress determinations in selected colliery roadways have revealed a range of measured stress from 330-p.s.i. tension to 3,750 p.s.i. compression. Photoelastic examination of loaded plastic and actual rock mo.odel mine openings has shown that the primary horizontal stress required to attain these measured stresses would be from one to three times the superincumbent vertical load.Examination of roof movement with a. borehole oxtensumeter and a series of anchors at various horizons to 30 feet in a. vertical roof borehole showed that when a standing face waa.s advanced the roofmovement was practically confined to the lower two feet. The ma.j ority of this movement occurred during the 36 hours after mining at this face commenced.The use of a. radioactive isotope and a. scintillation counter in a. pair of parallel bcreholes promises to be sensitive and accurate method of roof bedding plane crack detection.

Jan 1, 1963

By Williams D. J

The boundary element method is one of a number of tools that have found wide application in geomechanics for mine design and stress analysis. Two examples are presented in this paper, illustrating the use of the boundary element method to find potential problem regions in large-scale excavations. These examples are from a Papua New Guinea open cut mine and an Australian sub-level caving operation. Because of the scale of the mines and the complexity of the excavations, the boundary element method is the only practical numerical modelling technique to account for the major influences. Although the boundary element method uses only linear elastic models of the rock mass, the paper illustrates techniques for dealing with non-homogenous and anisotropic rock masses, as well as clasto-plastic effects associated with an excavation.

Jan 1, 1995

By B Bradák, D Asahina, S Saydam, S Akdag

Human exploration of Mars has been on the horizon of scientific goals for decades now, and as part of the objectives of human missions to various planets, one of the possible goals is opening new economic frontiers by the potential extraction and utilisation of resources, eg mining minerals and using surface regolith (Neukart, 2024). A comprehensive understanding of surface morphology, lithostratigraphy, basic structural geology, and civil engineering technology is essential to conduct mining operations for resource extraction on extraterrestrial planets. For instance, proper assessment of the risks associated with excavation and infrastructure construction under unique environments such as low gravity, surface irregularities, and the presence of regolith is fundamental. Such knowledge has been accumulated through satellite imagery and numerical topographic data using remote sensing technology, as well as seismic surveys by the on-site lander (Knapmeyer- Edrun et al, 2021; Banerdt et al, 2020; Giardini et al, 2020). Recent studies show that Marsquakes could be caused by the release of strain energy generated by the contraction of Mars. In particular, Marsquakes occur around the graben where many faults exist and form regularly spaced patterns. This implies that Marsquakes occur when the stress field of the Martian crust is an extension condition, and normal faults appear on the surface. In this study, we focus on so-called graben structures, one of Mars’s common tectonic structures (Plescia, 1991; Banerdt et al, 1992; Hoogenboom Hagen, 2014). The study aims to provide additional information about the tectonic environment during the formation of such features and, in addition, the internal mechanical-rheological structure of Mars, revealed by the geometrical pattern of faults modelled and simulated in a laboratory environment.

Sep 1, 2024

The results of a systematic geochemical survey of rare elements are applied to elucidate genetic relations in a suite of rocks and to predict the probability of mineralization. The geology, radioactivity, major element geochemistry and classification of the main intrusives are described. The distribution of a group of rare elements, their concentration trends and the bearing these have on the emplacement sequence of the rocks are considered in some detail. The guides for exploration in the Pilanesberg that emerge are listed and some areas which substantiate predictions are described briefly. It is concluded that a study of rare element trends can make a considerable contribution as an exploration tool and for clarifying relations between the members of rock suites.

Jan 1, 1986

By L E. Krause

This paper discusses the considerations for optimum maintenance of critical ore handling infrastructure in order to minimise the cost to the business of maintenance periods. As maintenance periods are a direct interruption to production, time is of the essence and careful management of shutdown periods is essential. The ore pass systems currently in use at Xstrata Copper û Mount Isa Copper Operations are up to 30 years old and have had significant wear over the years. The maintenance of these passes and their brows and chutes in a production situation is a challenge as it can potentially expose personnel to high risk situations in addition to the production interruptions. Some alternatives for mitigating the risk of working in ore passes including plugging and ballooning are described. Criteria are included for selecting a method for the safe entry into a given ore pass. Experience in adapting the method of ore pass plugs and some lessons learnt in the process are also discussed.

Jan 1, 2005

By Storey AG

Following initial plant scale work on the development and performance of 'spray' oil lances, a full scale room temperature model of the blowpipe-tuyere region of a blast furnace was built to study the basic aerodynamic features of auxiliary fuel injection procedures. Mobilwax 2305 was used as a substitute for Bunker C oil fuel in view of its similar physical properties and the fact that the atomised droplets could be frozen in flight and size, distribution analyses made for various operating procedures. It was shown that secondary atomisation processes far outweighed the importance of any primary atomisation procedures in determining mean Sauter Diameters particularly at high windrates typical of current blast furnace technology. It was also found that good spray dispersions across the blow pipe could only be obtaind for liquid fuels and that the lateral rate of spray dispersion was substantially enhanced by primary atomisation procedures. Mean particle diameters of sprays were found to be predictable on the basis of elementary stability theory and fell within the size range necessary for good combustion at all liquid fuel rates studied. The possible effects of high oil injection rates on flooding phenomena in the furnace bosh were considered. Comparisons show that high oil rates can lead to significant increases in the hanging factor (e.g. 'V 10% at 135 kg oil/thm) owing to increased gas flow rates/thm resulting from the presence of hydrogen.

Jan 1, 1975

By G R. Dickens, N H. S Oliver

The genesis of giant hematite ore deposits in northwest Australia remains a contentious topic in part because key evidence supporting a unifying genetic model has not been found at all deposits. In particular, several papers have proposed that carbonate replacement of silica layers in banded iron formation (BIF) by basinal brines is a requisite first step toward ore formation. This initial hypogene stage is inferred primarily from the presence of silica-poor, carbonate-rich rocks found below ore and along normal faults at the Mount Tom Price and Giles Mini deposits. However, until recently such rocks have not been identified at the largest martite-microplaty hematite deposit, Mount Whaleback. In this study, samples of the upper Mount McRae Shale are examined for their chemistry, mineralogy and petrography. These samples were collected from several key locations, including within drill core that penetrates an area immediately beneath ore along the Mount Whaleback fault at Mount Whaleback. Compared to unaltered black shale from Wittenoom Gorge in the north and altered black and red shale at Mount Whaleback, reddish-green shale below the Mount Whaleback deposit is significantly enriched in MgO and CaO and depleted in SiO2. Samples of this shale consist predominantly of fine- to medium-grained dolomite and ankerite cut by chlorite and carbonate veins, contrasting with unaltered equivalents that contain mostly stilpnomelane, K-feldspar and relatively minor carbonates. This alteration is distinct from assemblages developed during regional metamorphism, and possibly represents hydrothermal alteration after metamorphism. Although several questions remain unanswered, these results support models that invoke an early hypogene stage during the formation of the martite-microplaty hematite deposits in the Hamersley Province.

Jan 1, 2005

By H Zhang, Y Wang, S Sukenaga, H W. Ni, H Shibata, W Z. Mu

The crystallisation behaviour of low melting point CaO-SiO2-Al2O3-MgO inclusions greatly affect the deformability of inclusions during the rolling process. The crystallisation characteristics of CaO-SiO2- Al2O3-MgO melts representing the oxide inclusions in Si-Mn killed steel were systematically investigated. The effect of Al2O3 and MgO contents on the crystallisation change were analysed under a fixed CaO/SiO2 in the complex inclusions. The continuous-cooling-transformation (CCT) and time-temperature-transformation (TTT) experiments were conducted. The results showed that the increase of MgO content increases the crystallisation ability of CaO-SiO2-Al2O3-MgO inclusions, while the increase of Al2O3 content has the opposite effect. The viscosity, liquidus temperature of oxide melt and also the initial crystallisation potential might be the reasons for the change in crystallisation behaviour. Also, the crystallisation activation energy could semi-quantitatively characterise the crystal growth during the crystallisation of inclusions. To obtain low melting point plasticized CaO-SiO2-Al2O3-MgO (CaO/SiO2=1) system inclusions, the Al2O3 content of the system needs to be controlled larger than 15 wt per cent and the MgO content should be kept at a small amount.

Aug 21, 2024

By G W. Scott, R C. Johnson

Hypogene alteration zones have been described as a precursor to high-grade haematite deposits in Australia, Brazil and elsewhere. This alteration is described as being below or distal and is typically magnetite-carbonate-silicates reflecting Mg - Fe metasomatism. This paper describes, without genetic implication, the mineral zonation and possible structural control on mineralogic variation within the Tilden Mine, a concentrating grade haematite deposit in Michigan, USA. In contrast to the high-grade deposits, these variations are not peripheral to the orebodies but are the ore. The deposit occurs within the Negaunee Iron Formation, along the southern margin of the Paleoproterozoic Marquette Range Supergroup basin. The regional structure is a fault-bounded west plunging syncline within the crustal scale Great Lakes Tectonic Zone, which forms the boundary between Archean granite-greenstone and gneissic terranes. Local structure consists of second-order anticlines and synclines with variable northwest and southwest plunges. The interaction of sedimentation and diagenesis within growth fault controlled basins, along with a possible metamorphic and/or hydrothermal overprint has resulted in a complex series of ore types. For modelling purposes, the deposit is divided into geologic domains based on both lithology and metallurgical response in the laboratory and in the plant. Mineralogic variation is recognised within individual mineral grains; at blast pattern (10 - 15 m) and development drill hole (100 m) scales.

Jan 1, 2007

The author describes 1. The classification and characteristics of various thick seam mining techniques in various Japanese coal mines. 2. Practices of thick seam mining methods experienced in Taiheiyo Coal Mine. Currently, thick single lift, simultaneous multi lift and non simul- taneous multi lift mining methods are adopted as underground flat thick seam excavations in Japan. These are now reliable and effective in increasing the extraction ratio. At Kushiro Colliery of Taiheiyo Coal Mining Co., these three thick seam mining methods have been used. According to the results, if solidification of the top lift goaf is essential, the non simul- taneous multi lift mining method is the most effective in increasing the extraction ratio without minimising productivity of each lift and it points out that further development of this method is necessary.

Jan 1, 1976

By R Morrison, P Owen

Particle breakage is an essential part of mineral processing. The aim is to reduce run of mine mineral ore to an optimal size for liberating target minerals and for subsequent recovery by separation processes such as flotation. This size reduction is typically accomplished in a series of stages in a grinding circuit tailored to the properties of the particular mine ore. Commonly this involves two or more classes of equipment starting with crushers, followed by SAG mills and then sometimes ball mills. Occasionally, high pressure grinding rolls or other novel devices are substituted. Broadly, energy consumption increases and energy efficiency decreases with the fineness of the material produced by each piece of equipment. For many operations, up to 50 or 60 per cent of total greenhouse gas emissions from a plant arise from the operation of the comminution circuit with the majority produced by the finest grinding parts, such as the SAG and ball mills. Wear of mill liners and grinding media also add to greenhouse gas emissions generated by their manufacture. The need for continual cost reduction and increasing regulatory and social pressure relating to greenhouse emissions create a strong need for improvements in comminution energy efficiency. Traditional experimental and modelling approaches are not well placed to create the required insights into comminution fundamentals or facilitate radical step changes in performance. This paper discusses the role that advanced modelling (based on coupled DEM and CFD) can play in improving the energy efficiency and performance of existing mainstream grinding equipment and in the development of new ones with radically superior performance. Achieving this goal will also require an improved understanding of ore breakage and methods to include sufficiently realistic breakage models within the DEM models. Developmental issues for the modelling and the critical need for validation of the advanced model features are highlighted.

Jan 1, 2004

By P Hodkiewicz, K Noormohamed

Gold deposits in the Chirano district in south-west Ghana are hosted in a variety of structural settings along the Chirano shear zone (CSZ), in Paleoproterozoic rocks of the Sefwi-Bibiani belt. Most gold mineralisation occurs in strongly sheared and hydrothermally altered Birimian mafic igneous rocks and tonalite intrusions within the CSZ. A recent program of open pit structural mapping, core logging, and three-dimensional modelling helped to define deposit-scale structural controls on gold mineralisation. These include strain domains, shear zone flexures, shear zone intersections and vein arrays associated with host-rock competency contrasts. Interestingly, the plunge of higher-grade shoots in some deposits appears to be associated with the intersection of the CSZ and broadly folded Tarkwaian sedimentary rocks, which are not significant gold hosts in the Chirano district. This paper presents the results of 3D modelling that were used to define structural controls on mineralisation in several open pits and one underground mine along a 9 km length of the CSZ. LeapfrogÖ software was particularly useful because it highlighted the orientations of structural features that focused hydrothermal fluid flow during alteration and mineralisation. The improved understanding of structural controls provided two main benefits: near-mine exploration drill targets and better definition of structural domains for resource estimation.

Jan 1, 2009

The comparison of belt drives with other types of power transmission involves the consideration of many factors before a final choice is made. Where other forms of power transmission might also be suitable, the selection of the correct type of belt has first to be made, in order to obtain a true comparison. The paper first deals with the types of belting available, followed by a description of most other forms of transmission equipment. An example is then given of the selection of suitable belts, which are then compared with other types of transmission. Comparative costs are also given. Reference charts provided show drives found suitable in general practice...

Jan 1, 1964

By Leigh J. H

A history is given of the dust control techniques developed and applied by the mining companies at Broken Hill. A history of the regeneration works undertaken since 1936 is out- lined. Particular emphasis is placed on the stabilization of mine residue dumps which are located throughout a belt of mining leases in the middle of the city and which began in 1937. The establishment of vegetation for dust control techniques is discussed in detail and a case study is given of the successful revegetation of the sides of a 650 metre long, 350 metre wide and 35 metre high residue dump.

Jan 1, 1976