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By G Bournival, Y Saavedra Moreno, S Ata

Flotation frothers are heteropolar molecules that are preferentially adsorbed at the bubble interface to enhance the flotation performance by promoting the formation of small and stable bubbles. Frothers have different characteristics that can be used to classify them. A classification framework has been recently presented by Saavedra Moreno et al (2022) to classify non-ionic frothers by conducting a principal component analysis (PCA) and a hierarchical clustering analysis (HCA). However, for the purpose of the present research, only five frother characteristics, including molecular weight (MW), hydrophile–lipophile balance (HLB), critical coalescence concentration (CCC), the minimum Sauter mean diameter (DL), and foam stability index (DFI) were used in the PCA and HCA. All those characteristics were evaluated for a two-phase system in the absence of particles. Realising the important role that particles play in froth stability and behaviour, the effect of hydrophobic particles on the presented frother classification framework was investigated in this study. Four frothers with different characteristics, methyl isobutyl carbinol (MIBC), 1-pentanol, tri (propylene glycol) (TPG), and tri (propylene glycol) methyl ether (TPM), were chosen. The experiments were carried out in the presence and absence of silica particles esterified with 1-pentanol. It was evident that the results for 1-pentanol, TPM, MIBC, and TPG in the three-phase system agreed well with the frother classification presented for the two-phase system as frothers were clustered in the same groups. The findings from this research support the use of the frother classification system presented in two-phase system to select a specific frother for a particular application without the necessity of conducting laborious experiments in a three-phase system.

Aug 24, 2022

By G Baird, M Seto

A low-cost methodology that allows the determination of in situ stresses using oriented core specimens has been investigated. The technique can be used to determine the stresses during the early stages of a project, even in undeveloped areas of a mine. The research aim was to compare the experimental results estimated by the Acoustic Emission and Deformation Rate Analysis methods with those estimated by conventional Hollow Inclusion cell measurements. The studies have been focused on full stress tensor determination from a single oriented rock core. In all cases the rock core specimens recollected the in situ stresses reasonably well compared with the standard overcoring method.

Jan 1, 2000

By F Soleimani

Coal and gas outburst is a common hazard in coalmines and due to the complexity of its nature, efficaciously predicting the possibility of its occurrence is intricate. The mechanical and gas flow properties of coal, in situ and mining-induced stresses and geological structure are involved in outburst occurrence, whereas suggested thresholds for its prediction do not consider them all. Numerical modelling is known as an effective method that can not only consider couple the effect of different physics but also analyse the effect of associated parameters. In this paper, a coupled fluid flow and geomechanics model has been developed in COMSOL Multiphysics to simulate outbursts by considering the effect of gas pressure and composition, damage mechanics on related coal properties, and progressive excavation and mining-induced stress. For the proposed fully coupled outburst model, the effect of pore pressure and sorption are applied to the stress while the influence of stress changes and damage are considered in updating coal porosity and permeability in each time step. In addition, to study the effect of mining-induced stress, the excavation process is simulated by changing the material properties over time according to the schedule of heading development. Then, outburst initiation is analysed from the energy point of view by using the concept of energy conservation law. The simulation results are used in calculating energy sources of the outburst initiation, also, the effect of particle size and ejection velocity are studied, and the significance of particle size effect on the energy analysis and deformed coal on outburst initiation is discussed.

Oct 12, 2022

By Mortimer RR

The Weipa bauxite mining operation on the west coast of Cape York currently mines lb million tonnes of crude ore per year from the Andoom and Weipa mines. Andoom ore is trucked up to 4 km to a rail load station and hauled 20 km by train to the Beneficiation Plant. Weipa ore is trucked up to 7 km to the Beneficiation Plant. Increasing haul lengths and production requirements have led to a progression of larger two axle rear dump trucks and currently he intrcducticn of 145-tonne, three axle L t Dm dump trucks. bith the introduction of the Andoom a operation in 1972, the decision was made to use a railway system to haul crude ore from Andoom to Weipa. This system has proved to be successful from both an economical and operational view point. Due to the successful combination of a truck and rail haulage operation in Andoom, future :evelopment of orebodies requiring increased haul distances and increased production tonnages will probably result in extension r>f the railway system to compliment the trucking operation from the mine face.

Jan 1, 1978

The calibrated thermal IR data of part of Cambay Basin is used to determine surface temperatures and to detect the heat flow. Applying the conductive heat flow continuation technique, the three dimensional configuration of the hydrocarbon bearing reservoir was defined. The zone delineated by the present study coincides with the oil-bearing structures inferred by seismic survey. The results indicate the possibility of the technique as an effective tool in hydrocarbon exploration.

Jan 1, 1986

LESLIE BRADFORD GOLDEN JUBILEE ORATION "Not only a metallurgist but a scientist of the highest order" Leslie Bradford and the Australian Metallurgical Industry

Jan 1, 1987

By E Jak

A viscosity model has been developed for both completely liquid and heterogeneous, partly crystallised slags in the Al2O3-CaO-æFeOÆ-SiO2 system in equilibrium with metallic iron. The Urbain formalism has been modified to describe the viscosities of the liquid slag phase over the complete range of compositions and a wide range of temperatures. The Roscoe equation has been used to describe the effect of presence of solid suspension (slurry effect) on the viscosity. The parameters of the viscosity model were optimised to describe large experimental data set in the low-order subsystems, as well as in the multi-component system. The computer package FACT was used for prediction of the proportion of solids and the composition of the remaining liquid phase. The model provides a good description of the experimental data (over four thousand experimental points) in liquid phase, and liquid + solid mixtures, over the complete range of compositions and a wide range of temperatures. This model can now be used for viscosity predictions in industrial slag systems. An example of the application of the new model to slag cleaning and reduction smelting processes is given in this paper.

Jan 1, 2000

By T Mahlangu

The leaching of gold in alkaline aqueous cyanide solutions may be reduced significantly by the passivation of the gold by a surface layer of polymeric aurocyanide. This passivation of the gold is typically countered by the presence of Pb(+2) species in solution, which may be present as an impurity in the solution, or specifically added for this purpose. The speciation and availability of Pb(+2) in typical cyanide leach solutions is illustrated as a function of pH, and the presence of S(-2), S(+6), Cu(+1) and Ag(+1) species. The probable role of the Pb(+2) species in efficient gold leaching is discussed.

Jan 1, 2007

By H S. Mitri, A Sainoki

Destress blasting techniques have been widely employed in underground mines for the purpose of preconditioning highly stressed rock mass. Appropriate applications of the technique successfully contribute to increasing mine safety (eg mitigating the risks for rock bursts). This paper presents a simulation technique to estimate the extent of damage zones induced by destress blasting. A 3D numerical model with a single blasthole is constructed with FLAC3D code, whereby static analysis is carried out in which horizontal and vertical stresses are applied to the model in order to simulate stress conditions in a deep underground mine. Afterwards, dynamic analysis is performed whilst applying time-varying blast pressure along the blasthole. The blast pressure profile takes into consideration an instantaneous increase and gradual decrease in blast pressure as well as the propagation of detonation along the blasthole. In this paper, constitutive models allowing for shear and tensile strengths of rock mass that are dependent upon strain rate are newly implemented into FLAC3D code with C++ programming language, whereby blast-induced damage is assessed by the extent of tensile and shear failure zones. The results obtained from the dynamic analysis show significant decrease in the extent of yielding zones induced by destress blasting with increasing the magnitude of in situ stress. They indicate that considering in situ stress state is indispensable in order to propose proper blast design for each level in underground mines. Based on these results, the relationship between the extent of the damage zone and depth at which destress blasting is performed is established. Furthermore, stress dissipation induced by destress blasting is examined with static analyses, in which the modulus of elasticity is decreased according to a rock fragmentation factor, a, only for the area where tensile and shear failures takes place during the dynamic analyses. A model parametrical study with respect to a is undertaken. The relationship between the rock fragmentation factor and the stress dissipation in the yielding zones is developed from the parametrical study. The developed relationship can be useful when destress blasting is designed for massive rock masses.CITATION:Sainoki, A and Mitri, H S, 2015. Simulation of damage zones induced by destress blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 245–256 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The grinding of ore to a size that is conducive to the extraction of minerals by leaching or flotation is an essential and expensive component of most mineral-processing operations. Overgrinding results in reduced flotability of the minerals, as well as problems in the filtration and thickening processes, while undergrinding leads to a product in which the minerals have not been exposed, and cannot be leached or floated effectively. Furthermore, coarse material causes settling in thickeners and agitator tanks. It is therefore essential, from the perspective of both operational and extraction efficiency, to grind the ore to an optimum size fraction. A well-run milling circuit will yield a product within a narrow size band and at a high throughput. Although the effective operation and control of milling circuits with their many operating parameters is widely acknowledged as a complex as well as a critically important operation, the benefits of such control are difficult to quantify. This is due to the difficulties in relating more stable operation to increased recovery of the valuable components in downstream processes.

Jan 1, 1993

By K Marler

The Water Act 2000 includes provisions to manage the take of overland flow water. Overland flow water is water that runs across the land after rainfall either before it enters a watercourse, after it leaves a watercourse as floodwater, or after it rises to the surface naturally from underground. To ensure adequate environmental flows and long-term security for water users, it is necessary to balance the amount of water taken as overland flow water and the amount left to flow into watercourses. A water resource plan made under the Water Act 2000 establishes the basis for the sustainable management of this type of water. Of the water resource plans that have been prepared for Queensland catchments, six include provisions to manage the take of overland flow water. This paper discusses some of the common features of these plans and the management approaches adopted. The paper identifies and explains key aspects of the Water Act 2000 framework for managing the take of overland flow water by the mining industry. In particular it explains key concepts of this framework, such as the ability to take overland flow water using existing works, uses of overland flow water that a water resource plan permits, situations where a specific entitlement under the Water Act 2000 is required, and the means for controlling works that take overland flow water. Future initiatives for the regulation and management of overland flow water are then identified and particular challenges for the mining industry associated with using overland flow water highlighted.

Jan 1, 2006

By Robertson K. S, Hunter T. C

AEG-Elotherm's electromagnetic dosing channel, or Eldomet, is a recent invention enabling the transport and metering of molten metals. The development of a reliable refract- ory lining, and the use of suitable construct- ion and operating techniques has led to the successful application of the Eldomet for casting copper anodes at Copper Refineries Pty. Ltd.

Jan 1, 1974

By Magne L, Barria J, Castro O, Menacho J, Gonzalez GD

An extensive experimental campaign was developed in a continuous 6 x 2' (D x L) pilot scale SAG mill. The effect of the feed flow rate, feed solids concentration, ball filling fraction and feed size distribution, over the mill performance was investigated. The residence time distribution (RTD) for the fine material was measured in every test, in order to detect changes in the mixing characteristics of the mill under different operating conditions. Based on phenomenological considerations a state model of the SAG mill was developed, which independently incorporates mechanisms such as: grinding, mass transport and classification in the grate discharge. These can be parametrised using information and optimisation software. This comminution model extends the compensation condition, which is a conventional hypothesis for ball milling, to the semi-autogenous mill grinding. The mathematical analysis of this hypothesis, applied to SAG mills, allow the reduction of the number of parameters in the model, using the relationship Ki = (1-bii)Si, where b and S have the conventional meaning. Therefore, the distribution fracture matrix bij and the specific fracture rate SIE are grouped in just a single diagonal matrix Ki.

Jan 1, 1993

A series of numerical experiments were performed in order to define the fracture strength of schistose rock during crushing. Fracture strength was shown to decrease as the fabric aligned with the principal axis of loading. One of three types of characteristic stress-strain behaviour are defined by the orientation of the fabric with respect to the applied stress.

Jan 1, 1993

By P Dowd, R Jeuken, C Xu

In Australian coalmines there are a number of coal quality parameters that are measured by analysing samples from boreholes. The data points are used to generate spatial models of these parameters, typically using inverse distance as an interpolation method. Numerous additional boreholes are drilled which have geophysical logs measured downhole but from which no coal quality samples are taken. Full suites of coal quality analyses are expensive and time consuming to drill and sample. If geophysical proxies for coal quality could be used, this would greatly improve the accuracy of the resource estimation without additional cost.This paper examines two of the most important coal quality parameters – ash and volatile matter – and assesses the results of a number of geostatistical interpolation methods. The aim is to improve the accuracy of the interpolated models. Auxiliary variables from geophysical logs are also trialled to improve the estimation.A multivariate analysis of ash, volatile matter and several auxiliary variables of a selected coal seam was undertaken in a spatial context, using variography. This was used to construct a model of co-regionalisation that relates all of the variables as manifestations of an underlying geological theme.The traditional inverse distance interpolation approach was compared to ordinary kriging, universal kriging, co-kriging, regression kriging and kriging with external drift approaches. The relative merits of the six interpolation methods were compared by removing all points, one at a time and estimating at the thus known location. The mean error and the root mean square error were evaluated as a measure of bias and precision.This paper demonstrates that there is significant opportunity to improve the estimations of coal quality when using kriging with external drift. For example, the results show that when using the depth of a sample as an external drift variable there is a significant improvement in the accuracy of estimation for volatile matter. Furthermore, when using borehole wireline density logs as an auxiliary variable for ash content, there is improvement in the estimation of the in situ ash. The underpinning reasons for this are discussed in the context of the underlying geology and the physical properties of the coal. These findings hold promise for utilising cheaper proxies for coal quality parameters to dramatically improve data density and the quality of estimations.CITATION:Jeuken, R, Xu, C and Dowd, P, 2017. Improving coal quality estimations using geostatistics and auxiliary variables, in Proceedings Tenth International Mining Geology Conference 2017, pp 157–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

This is the time of year tor the presidential address, and with the present incumbent engaged in the coal mining industry, it will therefore come as no surprise to you that the theme of my address this evening is concerned with coal.There are other reasons for this apart from my contact with the coal industry. At present, coal is supplying considerable overseas revenue at a time when the remainder of the mining market is in a somewhat depressed state. That times will change goes without saying, if history is to be believed.However, so far so good for coal. My first reaction when The Institute indicated its wish that I be president for 1976 was to become deeply conscious of the honour bestowed on me.On consideration, I realized that very few past presidents have been intimately connected with the coal mining industry to the extent of indulging in it for lengthy periods as a full time occupation or, conversely, a part time interest for a long time. It also appears that not one had started their career in the industry. In my case, 'also, there were 8 very interesting years ,as a gold miner and metallurgist before commencing in coal.It therefore seemed appropriate to endeavour to discover ,why this should be so, as coal mining is now a very important part of a very important industry. What were the reasons why the industry took so long to emerge when there were ample reserves of easily accessible coal?Frankie and Johnnie in their bar room epic of the depression years concluded, and I paraphrase, that "their story held no moral, their story told no tale". If my story has such a message, it could perhapsbe construed as reinforcing the oft-repeated dictums, true or false, that "history repeats itself" or "man never learns".Coal mining is by far our oldest major Australian industry except for agriculture. Its history is almost as old as that of settlement:For various reasons, there has been a glamour associated with metal mining ventures which prob...

Jan 1, 1976

By J Hutchings

An essential component to the management of any process is the measurement of key parameters, used to monitor, control, and provide the feedback necessary for improvement. This paper discusses how data collection and analysis can provide a better understanding of the blasting process, as well as additional control and improved outcomes.The drill and blast process involves the generation and use of information at a number of levels. Comparison of historical parameters and results provides a starting point for the development of ongoing blast designs and a baseline against which future results can be compared. The collection of data during implementation provides a quality assurance/quality control (QA/QC) function where potential defects (such as under-drilled or over-charged holes) can be rectified prior to firing. Actual quantities and production rates allow the development of realistic plans and schedules, rather than using inaccurate estimates and targets that lead to unscheduled changes to equipment paths. Over?the past several years there have been a number of technological advances in data collection technology. Drill monitoring instrumentation on blasthole drills provides location information and feedback on rock properties as drilling occurs. Hand held ‘data logger’ technology has also overcome the challenges of working on the bench, such that blasthole measurements can be collected and forwarded directly to the explosive truck. Mine sites are becoming wireless network-enabled allowing the seamless data transfer from the field back to the office, in near real time, as that information is collected. Great strides have also been made in the development of drill and blast software systems which are more user friendly, and yet provide far greater capability to manage the quantity of data generated. The blasting process is critical to the overall mining process and the delivery of a successful blast outcome requires that the blasting process be ‘in control’. The measurement of key parameters can provide the data with which to measure and maintain control of blasting, and allows the validation of performance improvement measures and identification of improvement opportunities.

Nov 8, 2011

By Falconer A. J

Two magnetic parameters are proposed as a basis for the assessment of ironsands beneficiation. The parameters are deter- mined for raw sand prior to dredging and for magnetic separator head feed over a production period of five months. The relationships between these parameters and the performance of the magnetic separators are examined to establish the value of magnetic assessment compared with the traditional soluble iron assay method. The results illustrate that the first parameter, true magnetic fraction (TMF), has a value superior to that of soluble iron when relating raw sand grade calculated by tri- angulation to magnet performance. In terms of the relationship between magnet head feed grade and magnet performance, TMF and soluble iron perform equally as assessment parameters. For the ironsands mined during the five month period, the second magnetic assessment parameter, composite fraction (CR), is shown to merely reflect TMF and offers no additional information for assess- Ment. Conclusions are that true magnetic fraction has many advantages over soluble iron in terms of time and cost of determination and that it is a meaningful and reliable parameter upon which to base all calculations relating to the mining and beneficiation of ironsands.

Jan 1, 1980

Alcoa of Australia's Del Park mining op eration is centred 9 km. east of the Pinjarra alumina refinery, and is centrally locatedwith- in the 10, 000 sq. km. lease which the Company holds for bauxite in the Darling Ranges. An- other mining operation is situated near the township of Jarrahdale, and supplies bauxite to the Kwinana refinery. Definition of the bauxite ore, development works and mining to the ore haulage stage, are identical for both mining operations. Exper- ience, and production cost figures, obtained from the Jarrahdale mine, where 100 tonne trucks are used to haul ore to a fixed crushing plant, led to the development of the Del Park mining concept with increased mobility of op- erations. The crushing-conveying-stockpiling arrangement at Del Park consists of a 1200 t. p. h. mobile crusher feeding bauxite to an overland conveyor system which transports the ore approximately 6. 66 km. to the stockpile area in the refinery. In the refinery raw mat- erials area the bauxite is distributed into 200, 000 tonne stockpiles by means of a travel- ling boom stacker.

Jan 1, 1973

By Mckenzie CK, Leach KR, Bateman KW

Modelling of industrial coal flotation based on data collected in several Central Queensland flotation plants and supplemented by laboratory data is discussed. The model is kinetic in form and provides the basis of an automatic control system. The important features of the model are, 1. a distribution of flotation rates for each species of particles corresponding to the range of particle sizes, 2. a physical restriction on the removal rate of solids in cells where froth 'overloading' occurs. In this condition the removal rate of solids is proportional to the removal rate of water, 3. enhanced particle floatability due to increasing collector addition where froth overloading does not occur, 4. a second mechanism of recovery of all particles by mechanical associ- ation with water. This mechanism is particularly important in the recovery of fine high-ash species.

Jan 1, 1978