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By F T. Suorineni

Empirical methods are deeply rooted in geomechanics. This is a consequence of the recognised complexity of the nature of the rock mass. The usual assumptions of material continuity, homogeneity, isotropicity and linear elasticity often assumed for soil, concrete and steel are difficult to justify in a rock mass except for mathematical convenience. These assumptions form the bases for most mechanistic, analytical and numerical methods in geomechanics. Believers in empirical methods argue that the complexity of the rock mass and its interaction with structures developed in it is adequately accounted for in empirical methods, which compensate for our ignorance.Franklin (1993) defines empirical design as quantified judgement based on experience. He further states that empirical methods often prove ‘closer’ to the ‘truth’ than the apparently more precise predictions of theoretical analysis, adding that based on real data empirical methods provide a standard against which theoretical predictions are measured and can be judged. This paper takes a critical look at the common empirical methods in geomechanics – rock mass classification systems (Bieniawski, 1973; Barton, Lien and Lunde, 1974; Hoek, 1994a), Laubscher block caving design rules (Laubscher, 1994), the stability graph (Mathews et al, 1981), pillar design equations (Salamon and Munro, 1967; Hedley and Grant, 1972; and their derivatives), pillar design chart (Lunder and Pakalnis, 1997) and failure criteria (Hoek and Brown, 1980; and its derivatives). The common thread in the application of these methods is that in most cases they are often applied blindly without an understanding of the underlying assumptions and database limits. This paper emphasises that users of these methods need to know the underlying assumptions, database limits and inherent hidden risks that are often unmentionable for their satisfactory use. Finally, suggestions are provided for the efficient use of empirical methods and how they can be improved.CITATION:Suorineni, F T, 2014. Reflections on empirical methods in geomechanics – the unmentionables and hidden risks, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 143–156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By I Zh Bunin, V A. Chanturia, V G. Minenko, M V. Ryazantseva, A L. Samusev

A promising source for the extraction of rare metals and REEs in Russia is the eudialyte ores of the Lovozero deposit, which do not contain active uranium components. The eudialyte ore reserves of the Lovozero Massif are considered virtually unlimited and therefore have the potential to become a primary source of a number of rare and rare earth metals. The goal of this study was to comprehensively examine the effect of the parameters of high-power nanosecond electromagnetic pulses (HPEMP) and dielectric barrier discharge (DBD) on the leaching performance of eudialyte concentrate and the selective separation of zirconium and REEs from productive solutions. Using scanning electron microscopy and infrared spectroscopy, the mechanism behind the intensification of acidic dissolution of eudialyte as a result of pretreatment with energy impacts was described. During the HPEMP treatment, weakening and destruction of the eudialyte surface was observed, which at the substructural level is expressed in the deformation and local destruction of Si10O27, Si9MO30 resulting in formation of microcracks. During the DBD treatment, the formation of characteristic defects was observed in the form of imprints of dielectric breakdown microchannels and individual mineral fragments. Pretreatment of eudialyte concentrate using HPEMP made it possible to increase the recovery of zirconium into the pregnant solution of leaching by 3.4–4.3 per cent (from 86.6 per cent to 90.9 per cent) and by 4.1 per cent (from 86.6 per cent to 90.6 per cent) when using DBD. The increase in the total recovery of REEs was 1.2–1.8 per cent (from 87.7 per cent to 89.2 per cent). The effect of pH values, solution temperature, initial concentrations of valuable components on the successive recovery performance of zirconium and REEs from the pregnant solutions nitric from the acid leaching of eudialyte concentrate by chemical precipitation was examined. The possibility of selective separation of the zirconium product and rare earth elements with a zirconium recovery of 99.95 per cent and a REE recovery of 87.5 per cent was established. REE loss with the zirconium product was 8.0 per cent and 4.5 per cent with the spent pregnant solution.

Aug 24, 2022

Universal Resources Ltd has acquired a large portfolio of high quality exploration projects in two of Australia's most prospective regions for base and precious metal exploration: the Mt Isa Inlier (the Mt Isa-Cloncurry area) of North West Queensland, and the southern Lachlan Fold Belt in New South Wales. Drilling techniques commonly employed by the company for mineral exploration include diamond core drilling, air core drilling, reverse circulation (RC) drilling, and rotary air blast (RAB) drilling. Using examples from these two regions, each drilling technique is briefly described and compared, with particular reference to the specific advantages and disadvantages of each method for: sampling size, sample representivity, recovery, integrity and potential contamination. The applicability and implications of the different drilling techniques described for subsequent mineralogical and metallurgical evaluation work are discussed.

Mar 1, 2010

By C Li, S Wang, L Qiao

Jinchuan nickel mine is the largest nickel mine in China. Cut-and-fill mining method with high density cementing materials is used in the mine. The original mining design divided the mining operation into two steps. The first step stopped the mining rooms and the second step stopped the pillars. Because the two-step method made big trouble for finally mining pillars and strongly limited the mining speed and production, it was successfully changed to a continuous cut-and-fill method without pillars. However, the mining operation in the mine has been down to 800 m and the mining condition is getting worse and more complicated. Through systemetical field investigations and 3D FEM analysis, it is proved that the mining method without pillars is feasible for mining deeper orebodies in Jinchuan nickel mine.

Jan 1, 2000

By Q Liu

Open stoping is one of the widely adopted methods in underground bulk mining. In this method, fanned or parallel holes are often drilled from a top sill down to a sublevel in the ore zone and blasted ring by ring into a stope for excavation. A mass stope blast may involve blasting rock from multi-level drift rounds and displacing the muck to specific locations in order to allow safe and easy access for ore removal. This paper presents a strategic mass stope blast that took place at a large lead and zinc underground mine in eastern Canada. The blast consisted of more than 800 holes drilled in six blocks from three different sublevels. The challenge lay in the control of ground vibration and muck movement using precise timing to complete the blasting within 6.5 seconds. During this time span, sufficient voids were created in each level to allow the muck to move from the upper to the lower levels in sequential order across the six mining blocks without bridging. This paper describes stope blast simulations using a discrete element computer code for modeling blast-induced rock displacement as well as the application of electronic detonators. These detonators provided the means to accomplish the desired firing sequence including a drop raise blast at the start of the mass blast. The modelling concept is also described in the paper.

Jan 1, 2005

By A B. Christie, R Barker

Recent studies carried out to support the development of a strategy for the New Zealand mineral industry by the NZ Minerals Industry Association have included investigations of mineral potential, and the development of scenarios for realising this countryÆs mineral potential by 2010. New economic research is applying a general equilibrium model to quantify the opportunity cost of this potential. The model analyses separately four categories of land (private land and three categories of Crown land) and identifies four distinct mineral classes û precious metals, industrial minerals, coal and aggregate. It investigates the economic effect of the increased availability of mineral resources on the mining industry itself, on other industry sectors and on the NZ economy generally, including its impact on unemployment, GDP and household welfare.The analyses suggest that increases in the level of GDP of between 1.9 per cent and 3.4 per cent may be obtained by utilising New ZealandÆs mineral wealth to varying degrees. The mineral industry sectors are significant beneficiaries under all scenarios; mineral output increases by between two and five times its current level. However, the flow-on effects to the rest of the economy, and to households, are also significant. The analyses show that household income, adjusted for changes in consumer prices, can be expected to increase by between 1.6 per cent and 2.7 per cent. This results largely from increased employment.

Jan 1, 2002

By Ralph AM, Deakin JJ

A quantitative knowledge of underground mine ventilation requirements and conditions has become increasingly important, both to meet statutory requirements and to ensure high levels of safety and productivity within mines. The ACIRL Mine Ventilation System MINVENT was designed to provide a flexible means of analysing the behaviour of an underground mine ventilation system under a variety of conditions. It is not sufficient to rely solely on the analytical tools such as ventilation network analysis computer programs - these must be supported by the expertise necessary to conduct an accurate underground ventilation survey as well as experience of typical conditions to be expected in the evaluation of proposed extensions to a new or existing mine. When planning a new mine, the ventilation engineer can use the program to draw on a set of typical ventilation parameters, seam and proposed mining methods. These have been assembled as a result of numerous ventilation surveys conducted by ACIRL in New South Wales and Queensland.

Jan 1, 1983

By C Vejrazka1

The occurrence of airblasts is one of the principal mining hazards in caving operations between the time of cave establishment and breakthrough of the cave to surface. As such, it needs to be managed continuously and risk assessments need to be reviewed on a regular basis for applicability to changing conditions. The likelihood of an airblast occurring is based on a range of geotechnical factors over some of which engineers on-site only have limited control. However, the impact of an airblast to the underground mine, if it does occur, can be managed by following established safety guidelines for the production from the cave.This paper outlines how the Caving Airblast Simulation Tool in Ventsim was used to determine a risk management strategy for a sublevel and a block cave at a mining operation in Australia. The block cave has a footprint of 14 500 m2 with the extraction level located 1250 m below surface while the sublevel cave currently has a footprint of around 18 000 m2 operating between 660 m and 800 m below surface. Both caves are currently in their early operational periods. The risk analysis provided valuable information for the production planning of the caves including confirmation of extraction ratios for the block cave undercut, locations of airblast walls and maximum allowable air gaps for different muck pile heights to ensure safe operation is achieved.

Oct 12, 2022

The performance of the Australian Mining Industry over the past 10 years using key indicators of production, revenue, aftertax return investment, together with key cost elements, market changes and ore reserves is briefly reviewed. The elements of competitiveness are discussed forthe industry and the effects of Government charges and policies relating to existing operations are outlined. There is a demonstrated need for improvements in competitiveness in direct and indirect costs and for improved access to resources for the mining industry to continue to grow and add to Australia's economic growth.

Jan 1, 1987

The invitation to speak today was in the form of a single sentence instruction: How does your company run and how do you communicate from top to bottom? It looks like I'll have to let you into our little secret. The team at Croesus know what works for us but we've never talked about it with others - least of all presented it at a conference such as this. In fact we tend to avoid the jargon normally associated with Best Practice or TQM, however in our own way, each of our staff are 100 per cent loyal to our company's aim to maintain and strengthen our commercial success. Just how we achieve this at Croesus is the subject of this presentation today, but first a little history. My dear old grandfather arrived in Kalgoorlie, as a mining engineer 100 years ago. Do you think he would have chuckled if someone suggested to him that a hundred years later we would just be starting to understand Kalgoorlie's geological mysteries? Well, here we are 100 years later and Croesus Mining is fortunate to be part of a generation now realising the true potential of Kalgoorlie's Goldfields. This provides us with a very fertile field in which to sow the seeds we can obtain from the World's Best Practice in Mining and Processing. With each new mineral deposit being discovered, old theories are being exploded. Each new deposit has a personality of its own, leading to some belated pioneering theories of where to drill next, and how to reduce internal costs so that we can win the war against constantly increasing external costs. What we have now and what the old timers didn't have is a huge database of geological input spanning several gold booms and a couple of nickel booms. My only interest in history is to pick up the points that may help us for our future. This is what we are doing in our company which is something of a David, in the David to Goliath range of mining companies in Australia. As a humbling thought; of the 115 164 tonnes of gold that the world's mines have produced throughout history, four tonnes have been produced by Croesus Mining. That's equivalent to 0.003 per cent of the total world's gold production. In the past financial year we achieved a dividend yield of five per cent. To put this into perspective, that's over twice the dividend yield of BHP, Australia's largest company. As we are somewhat less known than BHP, let me spend a few moments giving some particulars of our company's background.

Jan 1, 1995

By Carter A. J, Miller D. M, Holder N. H M, Van Aswegen P C

The Harbour Lights Mine situated at Leonora in Western Australia, mines a refractory sulphidic gold ore. The main sulphide minerals are pyrite and arsenopyrite. Due to the association of gold with the pyrite and arsenopyrite, gold recovery is not amenable to the normal cyanidation process.A pyrite/arsenopyrite flotation concentrate is produced at Harbour Lights. This concentrate has been stockpiled for the past two years.A bio-oxidation process (BIOX«)* to treat refractory gold flotation concentrates has been developed by GENMIN in South Africa. Harbour Lights acquired the technology from CRL BIOX« Pty Limited in Brisbane, to treat the refractory gold concentrates.

Jan 1, 1992

By P Luo, J E. Danoczi, P Nakutnyy

Sensor-based sorting methods to remove waste or for upgrading ore prior to downstream metallurgical processing is becoming more prevalent for mining operations. X-ray transmission (XRT) sorters are a popular choice for mineral processing plants since they can sort a wide variety of minerals. XRT sorters pass high intensity X-rays through particles to generate images of varying greyscale, based on their effective atomic density. The ore sorter then mechanically separates the particles using algorithms based on the images. A popular test currently used to evaluate the amenability of the ore to XRT sorting is to pass the particles through the sorter and obtain the greyscale images showing mineralogical differences. This test provides information on the mineralogical heterogeneity between ore particles for their separation. However, it does not provide an understanding of the actual mineralogical composition of the ore or information pertaining to which other minerals may respond in a similar manner, nor does it provide liberation information. This paper describes a test that combines high resolution X-ray micro Computer Tomography (CT) combined with QEMScan to obtain information about amenability of ore to XRT sorting and to obtain valuable information that can streamline metallurgical testwork programs. This test also provides information relating to particle thickness and associated X-ray attenuation coefficients, desired mineral presence and mineralogical information relating to associated minerals and clays to assist with developing sorting algorithms. Combining the CT and QEMScan can address many limitations of the current method to determine whether XRT sorting technology is appropriate for particular ores. Mineralogy information from QEMScan can identify incidences of; mineral encapsulation, problematic clays, detrimental minerals as well as calibrate the greyscale values of CT data. Additional 3D CT imaging carried out on cores provides spatial information of the minerals within the ore and mineral grades.

Nov 10, 2020

By L O. Filippov, I V. Filippova

Subsea massive sulfide deposits have particular mineralogical compositions and textural features differentiating them from onshore ore. When extracted from salty water and exposed to the air, massive sulfide samples strongly oxidise and soon become covered by thin layers of iron, copper and zinc-rich sulfates and oxides, as well as elemental sulfur. The textural properties vary according to the degree of maturity and the sample position within the hydrothermal deposit. Because of the variation of secondary mineralisation and porosity level, sea floor massive sulfides respond differently from terrestrial ore to processing methods. Froth flotation, commonly applied to separate all types of sulfides from the gangue minerals, is one possible treatment technique to process sea floor ore. Sulfide recovery rate is, in most cases, excellent (>90 per cent). However, separation of the various mineral phases is difficult to obtain even when applying known methods used for onshore ore. Moreover, the flotation behaviour decreases dramatically with time of conservation, even when the samples were stored in a confined environment. High pH range, which is a good way to depress pyrite and therefore to favour the flotation of copper and zinc sulfides, does not have the same effect on subsea ore. Consequently, careful flotation procedure should be elaborated to obtain efficient mineral separation for this specific marine ore.CITATION:Filippov, L O and Filippova, I V, 2015. Processing of subsea massive sulfide ores by flotation – similarity and features with terrestrial ores, in Proceedings Third International Future Mining Conference, pp 239–244 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By M Xu and, P F. Wells, A N. Kerr, Y Shields

Triethylene tetramine (TETA) has been used in combination with sodium sulfite (sulfite) for pyrrhotite depression at Clarabelle Mill since 1998. This combination has been highly successful at reducing pyrrhotite levels in the bulk (Ni/Cu) concentrate. Although highly effective, the roles of TETA and sulfite are not well understood. Treating bulk samples of the circuit feeds through the miniplant enabled the effects of circuit configuration on the performance of the pyrrhotite rejection circuits at Clarabelle to be determined. Reasons for the different performance of the non-magnetic pyrrhotite rejection circuit in the miniplant were investigated and tested in the laboratory. The effect of different grinding environments in the laboratory was examined to better understand the depressing mechanisms of TETA/sulfite. Modification of the grinding chemistry improved the selectivity of pentlandite over pyrrhotite in the presence of TETA/sulfite at current plant dosages.

Jan 1, 2005

By Lukaszewski GM

The indiscriminate surface disposal of coal waste in the past has created a serious fire hazard in the bush of the northern New South Wales coalfields. Spontaneous or bushfire-induced combustion in large neglected dumps of this material has increased in recent years causing a rise in air pollution. Surface methods of coal waste disposal are still being practised, and in many cases new material is being added to old dumps, many of which are burning. CSI RO has conducted research on methods of preventing and controlling fires in coal waste and recommends practical methods of overcoming these problems. Some laboratory and on-site investigations are described and the hazards of improperly constructed dumps are considered. The available techniques of fire prevention and control are discussed in relation to Australian conditions. Proposals for the safe and economical disposal of coal waste are outlined.

Jan 1, 1970

By J Hadjigeorgiou

Narrow vein mining, as most types of mining, faces important geotechnical challenges. The specificity of geotechnical challenges in narrow vein mines stems from the nature of the deposits, which are often inclined, discordant and found within fractured rock or faults or in shear zones within country rock. This complicates the construction of representative geomechanical models and limits the applicability of several engineering design tools. Furthermore, in certain cases, the severity of encountered geotechnical problems is considerably greater in narrow vein than in wider orebodies. This paper provides an overview of geotechnical and other challenges in narrow vein mines with a focus on how these are currently addressed. Of particular concern is the use of manual labour working close to the mining face where there is greater exposure to geomechanical hazards. This review concludes with a particular emphasis on understanding the limitations of commonly used engineering tools and techniques to address geotechnical problems in narrow vein mines.CITATION:Hadjigeorgiou, J, 2012. Geotechnical challenges in narrow vein mining, in Proceedings Narrow Vein Mining 2012 , pp 15-22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By Xianguo C, Baoqi S, Shaozhong Z, Huiling Z, Zhengbing C

Acidless and fluoless flotation is a new method for separating feldspar from quartz at the natural pH value of tap water in the absence of any acid and fluoride and other inorganic reagents. The paper introduces the production application of this method in plants and research results on the mechanism involved in the flotation method.

Jan 1, 1993

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 A Woodley, A N. Danoucaras

In 2012 the Bureau of Meteorology, under the banner of the Water Accounting Standards Board, released the Australian Water Accounting Standard 1 (AWAS 1). This standard has been in development since 2007 with key milestones being the release of the Preliminary Australian Water Accounting Standard in 2009 and the exposure draft of the Australian Water Accounting Standard in 2010. Throughout this period, the Minerals Council of AustraliaÆs Water Accounting Framework has developed concurrently with the Australian standards and the standards have informed elements of the framework. However, the framework is not identical to the standard as the objectives between the two are different. The objective of the Water Accounting Framework is to create consistency in water reporting of the minerals industry and to assist companies reporting to corporate sustainability initiatives. The objective of AWAS 1 is to provide information to water management bodies to facilitate decisions about the allocation of water resources. Companies are to report on an annual basis - not only physical flows of water but contractual requirements to supply and obtain water - regardless of whether the transaction has been fulfilled in the reporting period. In contrast, the Water Accounting Framework only reports on flows that have physically happened. The paper will provide summary information on aspects of AWAS 1 that are most relevant to the minerals industry, show the alignment and differences between AWAS 1 and the Water Accounting Framework and explain how to obtain the information for the AWAS 1 reporting statements.CITATION:Danoucaras, A N and Woodley, A, 2013. Alignment and differences between the Australian Water Accounting Standard and the Water Accounting Framework for the minerals industry, in Proceedings Water in Mining 2013 , pp 85-90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By J P. Richards, M D. Johnston

The Porgera gold mine, located in the highlands of Papua New Guinea, produced 7.7 Moz of gold between 1990 and 1998. Reserves are estimated to be 12 Moz of Au. The deposit is associated with 6 Ma-old mafic alkalic intrusions emplaced at shallow levels into unconsolidated Jurassic and Cretaceous sediments, where they caused the formation of peperites. The mineralisation consists of an earlier base-metal-sulphide-rich stage with sericite-carbonate alteration (stage I), and a later phase represented by quartz-roscoelite veins (stage II). New styles of mineralisation and alteration have been recognised at depth in association with stage I. They consist of the assemblages magnetite-chalcopyrite-pyrrhotite and biotite-actinolite-anhydrite respectively. In addition, the recent recognition of adularia in some stage II veins (with roscoelite) confirms the similarity of this style of mineralisation with other adularia-sericite or low-sulphidation epithermal deposits.

Jan 1, 1999