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By K Nguyen

The advances in computerised processors and digital microscopic imaging have enabled more studies that attempt to quantify textural information from rock images. However, a texture classification system designed for geometallurgy has always been challenging, as it combines general image analysis techniques and specific texture classifications in terms of the size, shape and orientation of mineral particles. In this paper, a novel texture analysis technique using grey level radial shell association (GLRSA) and spectral angle mapper (SAM) to discriminate between different geological images is outlined. The technique can be applied in routine analysis and characterisation of mineralogical and textural attributes which may correlate with variability in mineral processing behaviours. Using this texture analysis technique, a set of small texture reference images, a texturelet reference library, has been identified from a suite of drill core images. Rock types are classified according to the proportion of each texturelet type recognised. The library is site specific.CITATION:Nguyen, K, 2013. A new texture analysis technique for geometallurgy, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 187-190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By D J. Williams, G W. Wilson, S, A B. Tran

A comprehensive field program was implemented to evaluate the internal structure and hydrology of two full-scale waste rock piles. The excavation of waste rock dumps for in-pit disposal at the two mine sites provided an opportunity to characterise the in situ properties of the dumps given contrasting geologic and climatic settings. The internal structure and materials within the dumps were observed and sampled as the waste rock piles were being excavated and placed in the open pits for permanent closure. The field program was designed to fully characterise the structure and material properties of the waste rock. The alteration of the material by physical and chemical weathering was also observed. Samples were analysed for paste pH, water content, grain size distribution and geochemistry. In situ density and matric suction were also measured. Soil water characteristic curves and saturated hydraulic conductivity were measured for representative materials. These properties were used to predict seepage pathways through the waste rock and the resulting outflow geochemistry using the finite element model SEEP/W. The materials in the dump at Site 1 were predominantly fine-grained in texture and highly weathered. The presence of dipping beds with alternating coarse and fine materials was evident throughout the profile of the dump. The structure of the waste rock appears to have an impact on the hydrologic pathways within the waste rock pile. The material in the dump at Site 2 was found to be competent and resistant to particle size breakdown. The particles range in size from clay size to large boulders with the median particle size being approximately 125 mm in diameter. The coarse-grained texture of the waste rock resulted in a loosely packed arrangement of coarse particles with little matrix material infilling the pore spaces between the coarse-grained particles. Seepage modelling for Site 1 was completed to predict seepage paths based on observed structure and hydraulic properties measured in the laboratory. The modelling showed that materials with a fine grain size distribution become the dominant pathways for flow through the waste rock pile. The modelling also showed that layers with high silt and sand contents are subject to the highest flow rates. Finer grained clay rich layers have a low hydraulic conductivity and do not convey large volumes of water. Alternately, coarse gravel and cobble materials are unsaturated under values of matric suction that approach the residual water content of the material and do not transmit liquid water. The seepage modelling together with the results of the geochemical analysis show that the dominant particle size that receives the most fluid flow and flushing ranges from fine sand to silt, corresponding to materials with air entry values ranging between 5 kPa to 50 kPa.

Jan 1, 2003

By K Muller, T Oosthuizen

Blast exclusion zones are instrumental in protecting equipment and personnel. When there is no constraint in footprint, the exclusion zone can be enormous, practically eliminating the hazard of flyrock. Unfortunately, this may not always be the case and in many circumstances the blast design needs to be altered to suite such scenarios. When a conservative design approach is taken, it could completely eliminate any form of ejection, whether it is from the free face or the bench itself. The degree to which typical flyrock models describe fragment motion through air with ballistic flight equations are not justified when such a high level of control is applied. This paper examines various methods of risk analysis and suggests an approach to be used for controlled blasting.The outcome of principles discussed in this paper can be seen in video form (Mavmedia, 2014).CITATION:Muller, K and Oosthuizen, T, 2015. Should the blast exclusion zone be based on a qualitative or quantitative analysis? A practical implementation conundrum, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 425–428 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By K H. Esbensen

The Theory of Sampling (TOS) has contributed significantly to chemometrics by allowing data analysts to become more aware of total measurement uncertainty as total sampling error + total analytical error. This has allowed a new view on, for example, validation of multivariate data models and their performance. This keynote focuses mostly on the reverse perspective: how can chemometric multivariate data modelling be of help in an augmented sampling context? The basic principles of multivariate data analysis are presented and application examples are outlined from several areas in the geosciences to facilitate answers to the question posed, including a geochemical multivariate anomaly concept defined by a multivariate background model. Applications from geochemical prospecting, geochemical mapping, environmental chemistry and anthropogenic outlier recognition are outlined, as are the interdependent relationships between geostatistical modelling (variographics) of singular variables versus linear combinations of a multitude of variables, in chemometrics called scores. The potential synergy between chemometrics and TOS is far from exhausted at this time; much work remains.CITATION:Esbensen, K H, 2014. Theory of sampling in a multivariate perspective – what can chemometrics contribute?, in Proceedings Sampling 2014 , pp 7–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By R Steinhaus, D M. Frantois-Bongarton, P W. Cleary, G K. Robinson, M D. Sinnott

Multotec Process Equipment and Dominique Frantois-Bongarton have a patent for a mineral sampling device, which they call a æTrue-Belt SamplerÆ. This uses a plough, which is rotated about an axis parallel to a conveyor belt to throw material off the belt. A fixed sample cutter takes a sample from the material thrown off the belt.Discrete element modelling has been used to consider a range of plough designs, plough speeds, positions for the cutter relative to the plough, cutter apertures, cutter designs and frictional properties, prior to the building of a physical prototype. This modelling work will be discussed, both as an illustration of the role of modelling in the development of new materials-handling devices and in order to explain the likely strengths and weaknesses of this new type of sampling device.CITATION:Robinson, G K, Sinnott, M D, Cleary, P W, Steinhaus, R and Frantois-Bongarton, D M, 2012. Modelling of a ætrue-belt samplerÆ - A new device for sampling from a conveyor belt, in Proceedings Sampling 2012 , pp 33-40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By M Kongas, K Saloheimo

Concentrating lower and more variable grade ore resources to meet acceptable concentrate quality criteria requires removal of significant amount of gangue minerals. Monitoring plant feed mineralogy and concentrate by on-stream analysis has significant economic benefits in concentrate quality and recovery optimisation. There is a need to develop a sensitive slurry on-line analyser for silica, aluminium, magnesium and other light elements.On-line XRF elemental analysis technology, which is a routine practice in base metal concentrators is not able to measure lighter elements than calcium from slurry. Too much of the X-ray fluorescence signal from lighter elements is absorbed by water. The limitations in the direct measurement of silica and other light elements have restricted its use in some applications. Some light element slurry analysers have been developed based on prompt gamma neutron activation (PGNAA) method but they have not performed up to the expectations. This paper describes a new on-line elemental slurry analyser and the results of on-line laboratory tests.CITATION:Kongas, M and Saloheimo, K, 2013. Online light element slurry analysis, in Proceedings MetPlant 2013 , pp 93-101 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By O Aydan, K Sugiura, A Sakamoto

It is well known that some sinkholes or subsidence take place from time to time in the areas where abandoned room and pillar type mines exist. The authors have been involved with the stability of abandoned mines beneath urbanized residential areas in Tokai region and there is a great concern about the stability of these abandoned mines during large earthquakes as well as in long term. The 2003 Miyagi Hokubu and 2011 Great East Japan earthquakes caused great damage to abandoned mines and resulted in many collapses. Particularly the effect of the quality of backfilling of abandoned mine below the urbanized areas is very important under static and dynamic conditions. The authors present the effect of the quality of backfilling on the ground subsidence associated with abandoned lignite mines under static and dynamic conditions and discuss its implications on the urbanized areas above abandoned lignite mines in this study. CITATION:Aydan, O, Sugiura, K and Sakamoto, A, 2018. The quality of backfilling of abandoned lignite mines on ground settlement under static and dynamic conditions, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 134–141 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

Zinc sulphide concentrate from Mount lsa, Australia, was leached in acidic sulphate-chloride solutions using ferric ions as oxidants under atmospheric pressure. The parameters of temperature, particle size and concentrations of ferric and chloride ions were evaluated.The shrinking core model can be used to describe the leaching which is limited by the electrochemical processes in the initial leaching stage, and by both surface reaction and pore diffusion processes subsequently. The apparent activation energy measured in the initial leaching stage is 49 kJ/mole over the temperature range 60 to 90°C.About 99 per cent of the contained zinc in the -45+38 µm particle sample dissolved at 90°C in a 0.5 M H2SO4/0.1 M Fe2(SO4)3/0.8 M NaCI solution within two hours. Some nine per cent of sulphide sulphur was oxidised through to sulphate; the remainder was convened to elemental sulphur.The mixed sulphate-chloride system has advantages over separate chloride and sulphate systems due to the low reagent cost, high leaching rate and possible selective leaching of zinc sulphide concentrate with high lead contents.

Jan 1, 1994

Near Kangiara in south eastern New South Wales, Australia, a number of polymetallic (copper, lead and zinc, with minor silver and gold) mineral deposits occur within a relatively broad volcanic rock belt, intercalated with limestones, sandstones and shales, of Silurian age. The Kangiara deposit was the most significant for the region.Adjacent to the Kangiara deposit, the unaltered country rocks are more rhyolitic than elsewhere in the volcanic rock belt, and the mineralization is accompanied by silicification, chloritization, sericitization and argillization. The host rocks typically contain a higher K20:Na2O ratio than the volcanic rocks not associated with mineralization.In the Kangiara deposit the mineralization consist of massive (in part banded), fragmental, disseminated and vein-type copper-lead-zinc ores, with the massive and fragmental types divisible into pyrite-rich, chalcopyrite-rich and sphalerite-galena-rich varieties. With respect to this mineralogy, the ore textures and sulphur isotope compositions the deposit can be compared to the stratiform mineralization associated with Silurian acid volcanic rocks at Woodlawn, Captains Flat and elsewhere in the Lachlan Fold Belt, as well as the Tertiary Kuroko deposits of Japan.

Jan 1, 1990

By Ramsay WRH, Morand V

Structural, mineralogical, and textural data from the Tarnagulla Goldfield demonstrate that the area has undergone three significant phases of deformation. The first phase of deformation (Dl) predates the intrusion of the Tarnagulla pluton, which has been dated using K/Ar as 391 ¦ 5MY. We regard this pre-granite deformational event as the major regional deformation. Gold-bearing quartz veins have been deposited in dilational sites on west-dipping reverse faults. These sites demonstrate a geometry related both to faulting associated with Dl and the plunge of the Fl fold axes. This evidence, together with chronology of unmineralised ? D2 and D3 faults, the absence of quartz veining associated with D3 events, and the deformation of carbonate-quartz-biotite-sulphide aggregates within Sl by later S2, lead us to conclude that the bulk of the mineralisation was essentially syn- or late Dl. S'80 values for fluids in equilibrium with vein quartz from Central Victoria have indicated equivocal support for either a magmatic or metamorphic origin. Our evidence supports a pre-magmatic origin for mineralisation at Tarnagulla and hence tends to favour a metamorphic fluid source.

Jan 1, 1995

Ore samples from the South, Central and North ore-bodies of the King Cassilis Mine, near Omeo, Victoria, were broken and transported to Melbourne for experimental metallurgical treatment. A microscopical examination of individual unoxidised specimens, selected from these samples, was undertaken in order to thro'w as much light as possible on the occurrence of the gold which forms the valuable economic mineral in the ore.The following descriptions are the outcome' of this examination and show that very minute particles of free gold are mechanically associated with the sulphides. While the gold may be separated from the transparent gangue minerals by the flotation of the sulphides, the, actual size of the particles indicates that it is impossible to separate all the gold from the sulphides by grinding the ore to pass through a screen of 200 mesh in which the average width of the holes is 0.063 mm. Chemical disintegration of the sulphides is essential to free all the gold particles and render them available to the attack of chlorine or of a solvent.It is interesting to recall that a metallurgical investigation on the Cassilis ore in the same district by K. A. Mickle in...

Jan 1, 1933

By B Smith, R Gelson

Springvale Colliery is an underground longwall mine situated approximately 10 km north-west of Lithgow in the western coalfields of New South Wales. Following a full-scale review of the mineÆs ventilation system in mid-2010, it was clear that the mine by early 2013 would become ventilation constrained as a result of the increasing size of the mine workings, the predicted worsening tailgate conditions and plans to introduce a fourth continuous miner unit. This realisation led Springvale to embark on a major upgrade of the mine ventilation system that would meet short-term and life-of-mine (LOM) requirements.Included in the upgrade project was the installation of a new high pressure centrifugal main exhaust fan that is capable of overcoming the high resistances imposed frequently on the circuit by restrictions in the tailgate airway. The new fan featuring a 2.5 MW motor is designed to be capable of operating at a quantity of 250 m3/s at a pressure of 7.9 kPa, a substantial improvement over the previous system, which had an operating duty of approximately 145 m3/s at 1.9 kPa. The new fan is of a centre hung design and features a backup diesel motor to maintain ventilation in the event of a power outage.Structural engineering analysis determined that under the operation of the new main fan the existing standard of ventilation control devices (VCDs) at Springvale would not be adequate to withstand the increase in differential pressures. As such, an upgrade of critical VCDs was undertaken utilising a novel high flexural strength (9 MPa) shotcrete and thin spray-on liner, which help serve to safeguard the structural integrity of the appliances and prevent increased leakage as roadway conditions at VCD sites deteriorate over time (a serious problem in many areas of the workings at Springvale).In addition to the main ventilation system upgrade, a separate upgrade focusing on improving development face ventilation was also undertaken. This upgrade included the purchase of two high capacity (22 m3/s) variable inlet vane (VIV) auxiliary fans to facilitate comfortable development face ventilation.The upgrade of the mine ventilation system at Springvale has been three years in the making, but has removed a major business risk in that it has afforded mine planning and operational flexibility (a fourth unit can now be introduced) for the LOM, and importantly provided unprecedented levels of comfort to operators at the working faces where previously ventilation and heat issues were frequently reported. The impact of this on the morale of the workforce, and hence their output, should not be underestimated.CITATION:Gelson, R and Smith, B, 2013. Life-of-mine ventilation system upgrade at Springvale Colliery - A case study, in Proceedings The Australian Mine Ventilation Conference , pp 79-86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Carlini G, Ibba R

The KSS Lead Plant (Kivcet - SNAMPROGETTI - SAMIM) of Por tovesme, owned by Nuova Samim (the sector-head Company for non ferrous metals and derivatives owned by ENI), has been operating since february 1987. This plant is based on the Soviet Kivcet licence and testwork carried out on the pilot plant of VNIITSVETMET in Ust Kameno gorsk fed by the Nuova Samim's concentrates. The plant is com pletely automatized using the most advanced technologies and it is operated by nineteen people on shift work, including all ancillary units and lead decopperizing-casting. The expected performance of the plant has been confirmed and improves day by day in relation of the operating experience, thanks to the new conceptual design of the furnace. Due to the remarkable flexi bility of the process, the integration of the lead plant with the other plants of the metallurgical complex of Portovesme rro-#4 (Electrolytic Zinc Plant, Sulphuric Acid Plant, Imperial Smel ting) has shown all the economic advantages. The lead content in the ambient air, detected by the monitors, either in the working area and on the ground outside the complex, is widely Pb W" below the stricter new limits recommanded by the E.E.C. (Economic European Community) rules and by the Italian law. The whole process is carried out in equipment completely closed and under suction and it does not require manual operations with exposure to the lead. The production cost is much lower than that performed by the traditional technology. This advantage permits wide margin to consider investment to replace the traditional technology.

Jan 1, 1989

Upon subduction, water is liberated from the sediments and the porous struc- ture of the oceanic crust and from de- hydration of minerals for redistribution and chemical reaction. A survey of pro- cesses which are likely to occur along the subducting plate reveals that water may well be basic in subduction induced gas generation, magma formation and ore deposition. In analogy to the industrial water gas process, reaction of water with car- bonaceous matter, in subducted sediments is likely to yield substantial volumes of hydrogen and carbon dioxide. While water and carbon dioxide appear to play a determining role in the development of differentiated magmas, hydrogen will react with metal sulfides and sulfur to form hydrogen sulfide which is essential in sulfide ore depo- sition. A survey of possible metal extrac- tion chemistry along subduction suggests a stepwise solubilization of metals from sediments and oceanic crust, and a poten tial accumulation of dissolved metals in zones of characteristic composition. The metal spectrum in ore deposits at near surface appears to reflect the com- position of the solution in the respec- tive subduction zone. A tendency for preferential solubi- lization of copper at subductidn level, from among the transition metals, an in- creasing generation of hydrogen sulfide in the sane direction and partition effects as well as sulfide precipitation characteristics lead to enrichment in copper and to its selective deposition in the direction towards the trench as observed in S. Latin America. A postscript deals with the formation of native copper.

Jan 1, 1986

By R-H Yoon

The thin film pressure balance (TFPB) technique was used to measure the kinetics of thinning of single foam films and disjoining pressures in the presence of sodium dodecyl sulfate (SDS) and electrolyte (NaCl). The results were analysed in view of the Reynolds equation to determine the role of surface forces in film thinning. It was found that film thinning is controlled by surface forces at thicknesses below approximately 200 nm. It was also found that hydrophobic force plays an important role particularly at low SDS and NaCl concentrations. The values of the hydrophobic force constant (K232) estimated from the film thinning experiments were used to predict the disjoining pressure isotherm using the extended DLVO theory, which were found to be in excellent agreement with experiment. The TFPB technique was also used to measure the equilibrium thicknesses (He) of the foam films stabilised by a non-ionic surfactant, n-octanol, in the presence of NaCl. At a given ionic strength, He increased noticeably with increasing octanol concentration at very low concentrations. This observation suggests that hydrophobic force is at its maximum level in the absence of surfactant and decreases with increasing surfactant concentration. The results obtained with the single foam films were used to explain the stability of the three-dimensional foams.

Jan 1, 2005

By J H. Park, M J. Lee

Because the environmental problems are occurred by greenhouse gases such as CO2, the industries have tried to increase electric motor efficiency to reduce CO2 emissions. A core material of electric motor is high-silicon electrical steel. The ferrosilicon (FeSi) alloy, a raw material for the production of electrical steel, affects the electric properties of silicon steel. The main impurities such as Ca, Al and Ti make inclusions or precipitates that causes core loss. The slag treatment has been widely used to remove impurity elements. Thermodynamic principles for the refining of several impurities, specifically Ca and Al, have been investigated, whereas thermodynamic behaviour of Ti has not been fully understood yet. Therefore, in the present study, the titanium distribution ratio () between ferrosilicon and CaO-SiO2-Al2O3 slag system at 1773 K was investigated. The results show that is influenced by both the basicity and stability of titanium ion in the slag. Specifically, exhibits a minimum value at about C/S=0.7 indicating a shift in the titanate structure unit from [TiO5]-square pyramid to [TiO4]-tetrahedron because of lack of Ca2+ ions in a C/S<0.8 region, contributing to an increase in titanate capacity and .

Jun 19, 2024

By Y Chung, B Choi, H Lee

Numerous studies have explored refractory corrosion in the presence of slag and/or metal, utilising the Finger Rotating Test (FRT). Recent experimental results revealed that corrosion initially increased with rising rotation velocity but was then suppressed above a critical rotating speed, under conditions involving a two-liquid solution of slag and molten steel. This phenomenon indicated that the liquid/liquid interface movement occurred during spindle rotor. However, understanding of the phenomenon, known as the rod climbing effect, remains inadequate in the case involving slag, molten steel and refractories. To gain deeper insights, a simulation experiment was conducted on the phenomenon using silicon oil/water and the phenomenon was analysed using computerised simulation software (Ansys Fluent). Experimental modelling demonstrated that interfacial movement occurs even at low rotation velocity, as low as 200 rev/min, when the viscosity of silicone oil is at 100 cP. Computational analysis utilising the Volume of Fluid (VOF) method and a realisable k-ε turbulence model elucidated that interface elevation during rotor rotation arises due to viscosity disparities between the two fluids. Furthermore, this movement is more pronounced when the viscosity difference is lower. Additionally, the study findings suggest that higher density differences between two liquids suppress the phenomenon of interface movement.

Jun 19, 2024

Through the stress synthesis of many examples of macrostructure in the middle of China, it can be concluded that in the middle of Chinesetectonics there are two compression-torsion-forces, one of which ( from NW to SE ) came from the northwest side of Aerjinshan abyssal and giant fault("F1A", see Fig.7,8,9 ); the other (from S to N ) came from the south side of the north piedmontal fault of Kunlunshan-the south piedmontal fault of Qinlingshan ("F2K-F2Q", see Fig-7,829 ).Owing to the two compression torsion forces a new special type of structure named rotation-apart structure occurred from Chaidamu basin to Hebai, Henan, Anhui plain,from Caledonian movement, Hercynian movement,Yenshan movement to Himalayan movement, step by step In the north of Qilianshan during the late Caledonian movement: during the Hercynian movement it extended into a vast area including the Chaidamu basin and Eerduosi basin; during the Yenshan movement it spread over the whole area of Helanshan,Eerduosi basin and Hebai , Henan, Anhui plain. In the period of Himalayan movement all these structures revived .The rotation-apart structure controlled the distribution of all mineral deposits and also were the mineralizing structures.The relation between these rotation-apart structure and earthquakes is very close.

Jan 1, 1990

By Whittaker B. N, Reddish D. J

The rockbolting method of support is employed widely in several countries in different of mines. Hard rock mines use this method extensively. Soft rock mines, such as coal mines, have employed standing supports (steel sets) as the main method, although some countries such as the U.S.A. and Australia have preferred rockbolting. There is increasing interest in extending the rockbolting method in coal mines. The application of rockbolting techniques in an industry which traditionally has not applied such techniques, has required the development of a systematic design approach. This design approach uses extensive monitoring, to asses the viability of the support system in differing conditions. Currently at a number of new and existing mine developments in the U.K., rockbolting is being successfully applied. Although, inevitably some localised geotechnical problems have been encountered and have needed to be taken into account. The effect of faulting on roadway conditions is discussed in this paper and a design approach has been applied using a numerical analysis method, namely the Finite Element Method. The results presented in the paper serve as a useful guide to roadway support designers, and in particular the role played by different bolts in a range of conditions.

Jan 1, 1992

By G Cormack

By designing comminution circuits for mineral liberation rather than the final recovery process and by using high mass pull gravity recovery, the concept of underground processing has become a reality. Gekko has found that many ores respond favourably to fine crushing with either high pressure grinding rolls or vertical shaft impactors which when combined with the InLine Pressure Jig gravity separator and coarse flotation results in a narrow, low-head, compact processing plant that can be sensibly fitted in existing underground openings. The focus on fine crushing reduces the power requirements of the plant to approximately 5 kWh/t for a capacity of up to 20 t/h run of mine ore feed. The use of water recycle systems places no extra load on the mineÆs normal water handling system. GekkoÆs underground processing plant, the æPythonÆ, has been designed to be towed down the decline or lowered down a shaft and is capable of being installed in sloping, non-linear drives for placement close to the working face. The overall benefit to mining companies of this concept has been estimated to be a significant operating cost-saving, lower cut-off grade and a significantly smaller environmental footprint.

Jan 1, 2008