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By D S. Collins, Z Hosseini, I Pinnock, Y Toya

Microseismic monitoring is regularly used in the mining and geotechnical industries to provide detailed information about rock mass response to operational activities. This paper implements a variable 3D velocity model (VM) at a North American hard rock mine with the aim of further improving the accuracy of seismic event locations. A collapsing method is also used to help analyse two individual seismic event clusters at another North American hard rock mine. In the first case study, the location accuracy of events is shown to improve by moving from a conventional single VM to a variable 3D VM that accounts for voids and different geological domains. The modal average for the event location accuracy improved from 14 m to 5 m when the 3D VM was used. Additionally, the single VM failed to locate 26 per cent of the seismic events that were located by the 3D VM. In the second case study, the distribution of seismic events was further enhanced by using a collapsing method that highlighted planar structures. The collapsing method was performed on two large event sequences that occurred in close proximity and identified different seismic event distributions. One aftershock sequence aligned along a plane, suggesting an activated structure, while the other large event sequence had a more 3D distribution of events, suggesting a complex stress redistribution on smaller structures.CITATION:Pinnock, I, Collins, D S, Toya, Y and Hosseini, Z, 2016. Large event sequence analysis and 3D velocity models for seismic event location accuracy, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 879–884 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By K H. Esbensen

The critical role of representative sampling is featured and illustrated by selected examples from the geosciences and beyond. As there already are many demonstrations of the potential (and potentially large) economic consequences of ignoring proper standards with respect to representativity, eg for mining and minerals processing companies, which æstand to lose millions of dollars by failing to optimise exploitation of their mineral resourcesÆ, such need no further iteration here.This keynote lecture, rather, takes a point of departure from the opposite perspective: what is to be gained by a scrupulous stand for representativity? Honesty, reputation, credibility, market advantage - is what!CITATION:Esbensen, K H, 2012. The critical role of representative sampling, in Proceedings Sampling 2012 , pp 9-12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

About 74% of global seismic energy release occurs in the Circum-Pacific zone. Worldwide, about 71% of seismic energy release is in the form of shallow earthquakes, 27% as intermediate, and 2% as deep earthquakes. Seismic energy release is variable in time and has been shown to correlate with the amplitude of the Chandler wobble. It was high during the period 1949 to 1967, and is now at a rather low level, with the latest earthquake over M = 8.0 having taken place in Indonesia in 1971. The average worldwide recurrence rate for the expected largest magnitude earthquake (M "9.5) has been estimated as several tens of years, in marked contrast to the several tens of thousands to hundreds of thousands of years separating the largest volcanic eruptions. Geological studies are needed to establish reliable mean intervals between large earthquakes, and to detect the e;:istence of long-term fluctuations in the ste of occurrence. Seismic gaps have proved seful in static forecasting of large earthquakes, by identifying places where closer study of the variation with time of seismicity, deformation, and other parameters, may lead to the dynamic p_ediction of time, place and magnitude of earthquakes. The model of stress concentration at asperities explains the main features of seismicity in the Circum-Pacific. Slow earthquakes have been detected instrumentally, notably an event immediately preceding the 22 May 1960 Chile earthquake, the largest this century. It seems likely that this type of deformation may explain both instrumentally detected and macroscopically observed pre-seismic deformation, as well as unusual animal behaviour reported before some earthquakes. Seismic and volcanic events are interdependent, with large earthquakes commonly triggering eruptions. Melting of rock and intrusion of magma is likely to accompany many earthquakes.

Jan 1, 1987

By Jensen B

The approach of using the Coward Triangle for the analysis of flammable mine gas mixtures has been examined for its application, to the flammability of coal dust/gas/air mixtures. Explosible lean limit and rich limit concentration data for dust/methane/air mixtures are examined and illustrated using co-ordinate geometry. It is concluded that a three-dimensional envelope representing hybrid explosible mixtures can be drawn. The dimensions of this explosive zone will vary with the characteristics of the coal dust and the gaseous composition of the mine atmosphere. Further research is needed to establish these dimensions for important mined seams.

Jan 1, 1994

By V A. Tsukerman

Prospects a new energy saving method for an efficient destruction of the sturdy and hard materials (rocks, ores, frozen soils, concrete blocks, etc) û the Electric Pulse Discharge (EPD) method of materials destruction for green processing in mining and processing of mineral raw materials are considered.The EPD-technologies give additional possibilities for solving ecological problems at the expense of increase of integrated approach of utilisation of minerals and industrial wastes. The scientific and technical level of executed development of EPD method is sufficient for organisation of design work to develop substantially new equipment. A number of plants have been developed and tested, including plants for processing raw material with minerals of jewels, plants for selection of mica from rocks, and plants for processing the merging of artificial mica.

Jan 1, 2002

The spatial and temporal evolution from the porphyry to high-sulphidation epithermal environment can be assessed by integrating new results on such deposits (Arribas et al, 1995; Hedenquist et al, 1998) with past studies of plutonic and porphyry systems (Dilles and Proffett, 1995; Cline, 1995; Shinohara and Hedenquist, 1997; Hedenquist and Richards, 1998). Some time ago, Sillitoe (1973) argued for the nature of the tops and bottoms of porphyry deposits. He concluded that epithermal deposits may form over the tops of some porphyry systems. We can now conclude more confidently what the tops and bottoms of many high-sulphidation ore deposits appeared like while active (Arribas, 1995; Hedenquist, 1995). In addition, we better understand the nature of the zonation of high-sulphidation epithermal systems from the intrusive to surficial environment (Sillitoe, 1999), and how these two styles of ore deposit are related. Geological and geochemical evidence clearly indicates a continuum between these two ore environments. This improved understanding of genesis allows more efficient exploration for these deposits. There are many examples of spatially associated porphyry and epithermal ore deposits. A genetic connection has been suggested by some, and argued against by others. Nowhere is this spatial association better seen than in northern Luzon, Philippines, where the Lepanto high-sulphidation epithermal Cu-Au deposit overlies the Far Southeast (FSE) porphyry Cu-Au resource (Figure 1). Together these mineralised bodies contain a resource of >3.8 M tonnes Cu and >550 tonnes Au. Lepanto was largely mined out in early-1997. Post-war production until 1995 was 0.73 Mt Cu, 115 t Au and 393 t Ag at an average grade of 2.2 per cent Cu, 3.5 g/t Au and 11 g/t Ag. The recent discovery of the adjacent Victoria low-sulphidation quartz-Au-base metal vein deposit, with a resource of >68 tonnes Au (Cuison et al, 1998), illustrates the variety and abundance of mineralisation in the Mankayan district. This district also hosts the Guinaoang porphyry Cu-Au deposit (Sillitoe and Angeles, 1985) and other epithermal vein occurrences (Figure 1). This brief summary reviews the results recently published on the Lepanto-FSE deposits (Arribas et al, 1995; Mancano and Campbell, 1995; Claveria, 1998; Hedenquist et al, 1998), and stresses the evidence for coupling of mineralisation between the porphyry and high-sulphidation epithermal environments.

Jan 1, 1999

By C Zhang, G Si, J Oh, X Zhu

The presence of rock joints has a huge impact on the strength, deformability, and permeability of fractured rock masses by providing surfaces of weakness on which further deformation are more prone to occur, and by serving as the major channels of water flow due to low matrix permeability. In earlier studies, water flow-through rock joints is often assumed as laminar flow between two ideal smooth parallel plates, and the well-known cubic law was derived and widely used to characterise the hydraulic behaviour of rock joints. However, natural rock fractures are irregular and of spatially varied aperture. Thus, the concept of equivalent hydraulic aperture was introduced to modify the cubic law. Numerous works have been conducted on the relation between hydraulic aperture and mechanical aperture incorporating various geometrical parameters. The surface roughness is one of the most sensitive factors for water flow-through rock joints. The aperture distributions are irregular in natural roughed fractures relative to the parallel plates. Barton et al (1985) and Olsson and Barton (2001) incorporated the joint roughness coefficient JRC in evaluating hydraulic aperture and proposed an empirical equation based on fluid flow tests. However, their equations do not conform to the dimensional consistency. Many other researchers (Zimmerman and Bodvarsson, 1996; Xiong et al, 2011; Li et al, 2019) considered aperture distributions in their equations. But the aperture distributions change during shear was always neglected. The contact of rock joints also has a significant impact on the hydro-mechanical behaviour of rock joint, since fluid tends to flow-through a rough joint along connected channels while bypassing the contact obstacles with tortuosity. Nonetheless, previous research mostly considered joint roughness or aperture changes based on 2D joint profiles, while the contact and tortuosity based on 3D surfaces were often overlooked. Only a few works have been made on quantifying the effect of contact area on flow behaviour (Walsh, 1981; Zimmerman et al, 1992; Zimmerman and Bodvarsson, 1996; Yeo, 2001), and mostly ignored contact area change induced by shearing and the associated impact on flow behaviour. Summarily, the quantification of fracture geometry effects on water flow in single rock joints still needs further investigation, especially when considering coupled shear-flow processes. This paper, therefore, aims to study the impacts of contact area and aperture distributions of the single rock joint on the flow behaviour. The evolutions of contact area and aperture distributions induced by shear are considered. Then, an improved model for estimating the hydraulic aperture with the mechanical aperture incorporating the above factors is developed. Finally, a series of shear and shear-flow tests are conducted on artificial joint samples and the model performance is verified by comparing against the results of experimental tests.

Nov 29, 2022

By Falbo A, Quarestima S, Cozza C, Barbaro M

A new synthetic reagent of the mercaptobenzoxazole class, 5- methyl-2-mercaptobenzoxazole, has been studied. This reagent exhibits powerful selective collecting action towards copper sulphides present in several complex ores, as demonstrated both by laboratory and pilot plant tests. Industrial production is expected to start in the near future. The way this reagent reacts with pure chalcocite has been studied utilising in situ FTIR techniques, adsorption tests, electrokinetic potential measurements and Hallimond cell flotation tests. The FTIR studies have indicated the nature of the surface phase. Adsorption isotherms obtained by the rest method have revealed the quantitative evolution of surface products, permitting the determination of surface coverage at various reagent concentrations. The electrokinetic potential has been utilised to verify the stability of individual species in diverse concentration ranges. Correlation of the results obtained has provided indications on the chemical interaction of this reagent with the surface and on the surface Arrangement.

Jan 1, 1993

By P E. H Gregg, R B. Stewart

Restoration trials established in 1985 included a treatment where pasture seed was sown directly into fertilised tailings. After seven years, accumulated soil data was used to compare physical and chemical changes in the plots with the original tailings control area nearby.   A known amount of annual fertiliser additions over the seven year period allowed nutrient balances to be calculated. Losses of S and P were relatively high at 72% of applied S and 28% of applied P. Calculations show that at least 240 kg N/ha/yr was fixed by clovers and this is likely to be under-estimated given that the calculation did not allow for leaching losses.

Jan 1, 1993

By Stewart Gillies A D, Just G. D

An internationally recognised and uniform method for classification, categorisation and designation of mineral and energy resources is not yet available. With the increasing need for reliable and comparable coal resource data it is necessary to standardise the traditional classification procedures by quantifying the three basic evaluation criteria of economic feasibility, geologic assurance and recovery. For well documented deposits, geostatistical methods can considerably improve classification quality. A review is undertaken of major classification with particular emphasis on those that incorporate limits on estimation error.A geostatistically based algorithm for classifying coal resources within the current Queensland and New South Wales codes has been developed.Application of the classification algorithm for resources from a number of seams exhibiting different structural characteristics is assessed. The method is found to give classification results that closely reflect the error associated with an estimate of resource quantities based on current sampling densities.lbis requires a careful geostatistical analysis with an emphasis on geological awareness. Resource category restrictions although albitrarily assigned should remain constant for all deposits being compared. This requires some engineering judgement with additional interpretation also required for isolated and peripheral block.

Jan 1, 1990

Modelling Channel Scale Flow in Heap Leaching Using Smooth Particle Hydrodynamics (SPH)

Sep 13, 2010

By W Schauenburg

The increasing problems associated with the disposal of waste and the potential for use of by-products as underground filling material is a subject which is relevant not only to the coal-mining industry. The progressive scarcity of surface disposal facilities for by-products and waste has now become a problem in all sectors - not only for the mining industry. The considerable capacity offered by underground cavities which exists in various mining branches present an extremely promising potential in this context. The backfill process for coal mining developed by DMT in co-operation with Ruhrkohle AG make use of the cavities which are offered by the extraction of coal. It consists of several stages: The fine-grained by-products, such as sludge, filter cakes, fine refuse, ash and flue-gas cleaning residues are processed on the basis of specified formulations in metering, blending and pump facilities on the surface to produce pumpable pastes with precisely defined flow characteristics. On Walsum Colliery of Ruhrkohle AG up to 200 m3/h stowing paste is conveyed into the mine in pipes with diameter of 200 mm (8"). The delivery pressure of the pump operating on surface in conjunction with the hydrostatic pressure of the shaft pipe - amounting in total to as much as 25 MPa - makes it possible to convey the stowing material for a distance 12000 m underground up to the workings without any need for additional booster pumps. Via a pipe installed in the face, the paste is pressurised into the cavities in the specially fragmented rock in the mined-out zone well behind the support. Consistent use of stowage of caved-in goafs makes it possible to reduce surface settlement above the workings. Fires in the stowed rock are either smothered or completely prevented thanks to the exceptional air-tightness in the caved goaf and the cooling effects of the slurry stowage. The reduced danger of fire, the preventation of air-leakage and the positive effects on gas emission from the coal improve safety in the workings.

Jan 1, 1998

Test Work on High Throughput Diamond Tracer Recovery from Alluvial Recovery Tailings with a Containerised Optical Sorter Under Real Production Conditions Worldwide alluvial diamond deposits are traditionally processed with dense media separation and XRF sorters, hand picking or grease tables. The test work conducted verifies the performance of an optical sorter detecting the transparency of particles for diamond recovery from the DMS concentrate, eg XRF-sorter and handpicking tailings. The containerised setup enables economically feasible, high throughput, semi-mobile setups to retreat recovery tailings from alluvial and also primary deposits. The test work has been conducted with quartz and glass particles, which are less transparent or comparably transparent, under realistic production conditions on a 600 mm belt machine with an installed electrical power of only 21 kW. The results show that 99 per cent recovery can be reached at a throughput of 10 t/h in the -8 + 2 mm fraction and at 22 t/h in the -25 + 8 mm fraction. At a throughput of 18 t/h a recovery of 88 per cent has been assessed. At a further escalation of the throughput, dust in the sorter container made sorting impossible in the coarse fraction and the recovery decreased significantly in the fine fraction. Analysis of the belt coverage indicates that higher throughputs of the coarse fraction can be fed onto the optical sorter if the dust extraction system is improved. The results are basis for the decision to conservatively feed 20 t/h of the coarse fraction and 17 t/h of the fine fraction in day to day production. The settings have been applied to sort alluvial recovery tailings in South Africa and will be applied to sort the recovery tailings of a primary deposit in Lesotho. The test work has shown that an optical sorter can be used to retreat recovery tailings with high throughputs. The compact setup of a screen and a 9 m standard container enables semi-mobile, temporary setups for small recovery tailings dumps and remote areas. In addition, sorting on transparency ensures the recovery of high value low-fluorescent diamonds.

Sep 13, 2010

Ore sorting is a high capacity, low cost method of pre concentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal subsystems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry. The suitability of different ore types for pre-concentration using anyone of the variety of ore sorting systems can be quickly established using computer based techniques which require only small samples of the materials under investigation.

Jan 1, 1980

By J M. F Clout, E Donskoi

The ability to design a beneficiation process for a new orebody based on particular feed characteristics is a powerful and practical tool. A new technique has been developed where beneficiation outcomes can be calculated by combining feed size-by-size chemical analysis, mineralogy, liberation and particle characteristics with a series of simple theoretical unit separation models rather than a simple mass balance approach or an exhaustive beneficiation test program. The new technique provides the ability to rapidly identify ore types that have the potential to meet product specifications whilst also rejecting others that will not meet specification even if a perfect separation was achieved. Beyond the broad scale decision making process, practical mineral separation curves from actual plant data can be used to more closely simulate the proposed process. This approach reduces the amount of laboratory and pilot plant work necessary by targeting what process stages will be required, increases early rejection of uneconomic options, identifies problematic ore types or unit operations and is a step towards estimation of final grade and recoveries achievable in potential circuit configurations.

Jan 1, 2004

This paper considers the application of recent laboratory gas sorption data to the understanding outburst phenomena in underground coal mining. Previous use of threshold limits based on gas content and coal rank are placed in perspective. Although this work focuses on overseas research and experience, parallels can be drawn for New Zealand coal settings, taking into account localised mining and geological factors.

Jan 1, 1994

By J Johansson, J Lööw

There are many reports about how the new technology will affect our work, sometimes they are utopian but often dystopian. Most of the visions describe the industrial work, while the work of the managers does not seem to be affected. In this article, the authors will discuss how the new technology within the concept of Mining 4.0 changes the conditions for leadership and the work of managers in a modern mining industry.

Sep 1, 2024

By Brady KT, Pattenden G

A laboratory size solvent extraction apparatus has been constructed, which incorp- orates three stages of countercurrent extraction, followed by two stages of counter- current stripping. The model uses a gravity flow system from one stage to another and air lift pumps to recirculate organic and aqueous phases. A novel pump/mixer system is used to transfer solutions from the mixer compartments to the settler compartments. The model has proven valuable in the teaching of solvent extraction principles.

Jan 1, 1984

By A R. Proudman, A H. Purvis

The Granites Gold Mine Callie gold deposit is located 550 km northwest of Alice Springs in the Tanami Desert. Gold mineralisation occurs due to a complex interplay of geological factors which include but are not limited to favourable lithology, structure, alteration and quartz veining. High-grade mineralisation, while pervasive under favourable conditions, is highly variable over short distances and is very nuggetty. In contrast, the lithology and geological structures that host the mineralisation are very continuous. Orebody modelling techniques have evolved over time because of a growing understanding of the mineralisation controls. Modelling issues such as sampling and assaying accuracy, modelling method, data density, gold population statistics, geological interpretation and domaining, grade boundary and calculation conditions, and model block size are constantly being reassessed in an effort to increase understanding of the mineralisation controls and modelling accuracy. The evolution of the modelling process in response to increasing data levels and a growing understanding of the mineralisation controls has resulted in changes to the perception of the orebody size and style. This has caused the choice of underground mining method to be revised several times and the process to final mining method selection to take longer than usual. In order to achieve the planned production start-up date of July 1998 the process has been allowed to progress in parallel with development of the underground mine. This paper describes the resource modelling and mining method selection process applied to the Callie underground mine and some of the issues which have contributed to its evolution. Some conclusions that are relevant to the efficient planning and development of new mining projects in general are presented.

Jan 1, 1998

The Western New South Wales Electric Power Proprietary Limited is the central generating authority for distribution of power to the majority of the Broken Hill mining companies and the Broken Hill Water Board. This station supplies the whole of the power to North Broken Hill Ltd and Broken Hill South Ltd. It also supplies, power to the Southern Power Corporation for distribution to the Zinc Corporation Ltd. The Southern Power Corporation has a generating station which is tied in with the central generating authority.

Jan 1, 1957