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By C G. Sweeney

The underground mining industry is seeing unprecedented shortages in skilled labour. Migration to Australia being at an all-time low is a leading concern, with pandemic-induced border closures and lockdowns only exacerbating the skills shortage, not causing it. The skills shortage is forecast to peak in 2023 and remain high beyond 2025. With this skills shortage in mind, mining companies throughout Australia are trying to deal with stricter protocols around Health and Safety (H&S) legislation, as well as more stringent controls on quality assurance, particularly as underground mines are reaching greater depths and extending into ‘unchartered territory’. The cumulation of this is proving to be a major hurdle in ‘effective’ operational geotechnical management. The drive for automation in mining is bringing another level of complexity. However, ‘once automation is up and running, it presents the opportunity to access talent pools that may not normally be available. There is also a change in skillset that will be required to drive automation. ‘The top two emerging roles that will be critical for the future of the mining industry are artificial intelligence and machine learning (AI/ML) specialists, and process-automation specialists’ (Writer, 2021). If anything positive has come from the pandemic, it has shown that remote working can be effective and that the drive for automation and critical evaluation of skills required on-site should be given greater priority. UQ acknowledges that the industry is changing, and that digital technology is required to be offered in mining related disciplines. Industry and academia need to do more to promote geotechnical engineering in mining and balance the curriculum to suit the future of mining and make it more enticing. The average cost of a geotechnical failure is about $5 million in coalmines and can be into the hundreds of millions of dollars if production is affected (Cartledge Mining and Geotechnics, 2020). The cost of a good geotechnical design far outweighs the potential losses if a failure were to occur. This alludes to the growing importance of experienced geotechnical consultancies playing a pivotal role in managing mine site geotechnical hazards, while the industry is developing the next generation of geotechnical engineers.

Nov 29, 2022

By Abdurazakov A, Avrakhov A, Solozhenkin P

The flotation properties of acetic acids modified by xanthic and dithiocarbamic fragment in regards to copper and ferrous minerals and their noble metal containing ores have been investigated. The effectiveness of the co-using of these reagents with xanthates and dithiocarbamates has been shown, ie using of proposed reagent regimes for the flotation of Au-containing ores increases gold recovery by 4.2 - 4.7 per cent, and in the case of flotation of copper Re-containing ores copper recovery increases by 3.3 per cent, rhenium recovery - by 15.5 per cent. The mechanism of the action of these reagents has been explained by the data of UV and ESR-investigations of their sorption on mineral surface. The information on structure and properties of co-ordination compounds of some metals with (Diethyldithiocarbamato) acetic acid were used also for the explanation of flotation mechanism.

Jan 1, 1993

By Canterford J. H, Sparrow G. J, Dyson N. F

Pressure leaching of a bulk flotation concentrate prepared from a complex Cu-Pb-Zn sulphide ore was carried out at 150 and 190¦C under 1050 kPa oxygen overpressure in 1 L and 4 L titanium autoclaves to extract zinc, and to obtain residues for smelting tests and leach liquors for purification and recovery of the zinc by electrowinning. Dissolution of 95% of the zinc was achieved at both temperatures. Copper and iron dissolution and the degree of oxidation of the sulphide sulphur to elemental sulphur or sulphate depended on the temperature of the leach. At 190¦C, a jarosite (a basic iron sulphate) was the major iron-containing material in a residue that contained 17% total sulphur. Its formation was associated with dissolution of 18% of the iron. At 150¦C, oxidation of the sulphide sulphur and dissolution of the iron were significantly less. Only 7% of the iron was dissolved and a residue containing 25% total sulphur, present as a lead jarosite, lead sulphate, and elemental sulphur, was obtained. The formation of small pellets of unreacted sulphides coated with elemental sulphur caused problems during the leaching at 150¦C, and also during scale-up from the 1 L to the 4 L autoclave at 190¦C. At 150¦C the concentrate required two stages of leaching to achieve dissolution of over 90% of the zinc. These problems are discussed.

Jan 1, 1989

By V A. Chanturia, T N. Matveeva, V V. Getman, A Yu Karkeshkina

The development and application of new effective environmentally friendly reagents for the flotation of thin and ultrathin mineral components is an urgent task. The analysis of the nomenclature of chemicals, including flotation reagents and flocculants, showed that water-soluble polymers (WSP) might be used in flotation separation of fine grinding products containing non-ferrous and precious metals. Water-soluble polymers that are responsive to temperature changes are the most attractive as reagents during flotation. These are the thermo-responsive polymers or thermomorphic polymers. The presence of nitrogen and oxygen atoms in the polymer molecule contributes to the formation of a coordination bond with non-ferrous and precious metals. A research conducted at the ICEMR RAS within the framework of the scientific school of Academician of the Russian Academy of Sciences Chanturia helped to develop a method of flotation of finely ground mineral particles containing valuable components using modified thermomorphic polymers. The paper focuses on the experimental study of poly (vinyl caprolactam) (PVC) as a flotation reagent for gold recovery from finely ground mineral products. PVC is a ready-made water-soluble thermosensitive polymer that does not require complex synthesis. PVC has a high ability to form complexes in an aqueous environment when heated. According to experimental data, the polymer interacts with gold nanoparticles, contributing to the extraction of gold from fine mineral products and the tailings that makes it perspective as an additional flotation agent for the processing of gold-containing ores.

Aug 24, 2022

By D J. Fray

In this work, a fused salt electrochemical process was investigated experimentally for production of metals and alloys directly from respective solid oxides by electro-deoxidation. Direct electrochemical reduction of the oxides was carried out in molten CaCl2-based chlorides in an electrolytic cell, incorporating an oxygen-evolving inert anode, over the temperature range of 850 - 950¦C. The technical viability of the process was demonstrated by the electro-deoxidation of pure oxides and oxide mixtures including NiO, Nb2O5, Nb2O5/TiO2 and Nb2O5/SnO2 to produce nickel metal, niobium metal, NbTi alloys and the intermetallic compound, Nb3Sn. Compared to the conventional metallurgical processes for producing these metals and alloys, this new electrochemical process appears to be much less energy intensive, with lower costs and no direct greenhouse gas emissions from the electrolytic reduction process. The present electrolytic reduction process has the potential to be scaled up for the green extraction of a number of non-ferrous base metals and processing of many advanced alloys.

Jan 1, 2006

By M Lee, J F. Carswell, G Reitsema

"The increased costs of underground mining have continually challenged engineers to identify opportunities for alternatives to common approaches to underground development. Considerations to the design of horizontal and vertical development at the Dugald River mine targeted inclined raise boring to reduce horizontal development, not only to reduce cost, but to allow development activities to focus on other areas of the mine.The mine plan consists of 50 raise bored ventilation shafts, of which 17 have been mined to date with diameters ranging from 3.1 m to 5 m and lengths from 30 m to 200 m. The expected performance and stability of these shafts has been determined using methodologies proposed by McCracken and Stacey (1989) and further refined by Peck, Coombes and Lee (2011). Actual raise performances have been collated and compared to a database of raise bore performances across Australia as presented by Coombes, Lee and Peck (2011), and form a database of raise bore performance specific to Dugald River.Opportunities to further optimise the mine plan and reduce costs have seen the introduction of large diameter-inclined raise bored ventilation shafts to minimise the required lateral development to connect the ventilation circuits. Large diameter inclined shafts ranging between 3.1 m and 4.5 m in diameter have been successfully mined with dips down to 70°, reducing the cost of lateral development by more than $1 million over the next two years.Both technical and operational challenges were overcome in the mining of large diameter-inclined raise bores, including modification of: existing methodologies of assessing shaft wall stability for inclined raises. These included variations of the McCracken and Stacey method and the utilisation of the modified stability number (N’) previously developed for stope performance (Potvin, 1988). both the collar and toe development profiles, including the general set-up of the raise bore drill rig to reduce the operational risks associated with angled raises.Due to their success, inclined raises have been designed for subsequent stages of the life-of-mine ventilation system at Dugald River. This has resulted in significant capital cost savings for the mine.CITATION:Carswell, J F, Reitsema, G and Lee, M, 2017. Vertical and inclined raise bore performance at Dugald River mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 313–320 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By McLennan T, Howells E, Zastawny H, Watt J. S

Nuclear techniques have been used to determine the solids weight fraction (W) and ash content of (fine) coal in slurries independent of voidage variations. The method is based on the correlation between W and the hydrogen concentration Hsl (wt/wt) of the slurry. Hsl is determined by combining measurements of neutron moderation and ?-ray transmission. Both Wand ash content are determined by combining the above measurements with the ash-sensitive measurement of X-ray backscatter compensated by a measurement of iron K X-ray intensity.The nuclear analysis system, called the SIRO coal slurry gauge, has been proved in a six-week plant trial at the BHP Steelworks washery at Newcastle, NSW. Several probes, each containing a radioisotope source and scintillation detector, were immersed directly into the coal slurry in the feed box upstream from the bank of flotation cells. For 140 samples W, ash and voidage varied in the ranges of 0 to 13 wt percent, 26 to 41 wt per cent and 0 to 4 vol. per cent, respectively. The r.m.s. difference in solids weight fraction, determined by probe measurements and conventional assay, was 0·52 wt per cent. Ash was determined with an r.m.s. difference of 2·0 wt percent in the coal. Better sampling techniques were used in the last half of the plant trial, and r.m.s. differences were 0.35 wt per cent solids and 1·5 wt per cent ash.

Jan 1, 1986

By I Neilsen, A Walker, A Hooper

Final landform planning in Deswik software was used to determine if integration into the mine plans could achieve better closure outcomes. Using the dump surface outputs from the Deswik Landform and Haulage Simulation (LHS) and the Reshape Landform tool, the project intended to:1.Review costs to achieve the final landform for several grade criteria scenarios;2.Quantify reshape volumes at several stages of the mines development with the objective to contribute to margin ranking inputs; and3.Identify rehabilitation cost reduction measures such as backfilling ramps and pits.CITATION:Neilsen, I, Walker, A and Hooper, A, 2018. Case studies for integrating rehabilitation planning with mine planning in strip mining, in Proceedings Life-of-Mine 2018, pp 93–95 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By A Tolley

Bauxite residue or ‘red mud’ is a by-product of the Bayer Process, the primary process of alumina refining. Due to its high alkalinity and variable composition, its storage and disposal poses high environmental risks to water sources, surrounding ecosystems and human health. The high alkalinity (pH 12–13) is a significant factor in its classification as hazardous waste; to mitigate this, Australian refineries have integrated neutralisation processes into bauxite refining. Both sea water and carbon dioxide neutralisation processes are applicable. Multiple studies have demonstrated pH reduction from 12–13 to 7–10, depending on the method. The key advantages of CO2 neutralisation are that it allows for carbon sequestration and is more effective when utilised as a pre-treatment for recovery of metals, while sea water neutralisation is more established and has been integrated into two Australian refineries. This paper proposes the application of the bacteria Exiguobacterium oxidotolerans for bioleaching of iron from hematite in bauxite residue. The genus Exiguobacterium is characterised by its high levels of adaptability, halotolerance and alkaliphilic nature. E. oxidotolerans is successful at eluting Fe2+ from hematite via reductive dissolution, which complexes with oxalic acid produced during metabolism. This aquatic bacterium presents a novel process pathway for iron elution due to direct interaction of E. oxidotolerans with hematite via the cell membrane and operates within the pH range of neutralised red mud. The proposed mechanism is extracellular electron transfer, a microbial metabolic process where electron transfer is facilitated between bacterial cells and extracellular material. Currently this is being investigated for promotion of seaweed growth in coastal environments as soluble iron aids and fortifies colonies. This has potential downstream applications for cleaner iron and steel production. While theoretical, this paper explores the neutralisation, bioleaching and application of the Fe(II)- and Fe(III)-oxalate complexes formed.

Sep 18, 2023

By J S. J van Deventer, D C. Shallcross

New developments are taking place in the recovery of gold from leached pulps that are based upon the adsorption of the metal cyanide species onto ion exchange resins. Despite the success of several resin-in-pulp pilot plant operations in the Western World and large-scale plants in the former Soviet Union, the process is yet to gain recognition as a viable alternative to the carbon-in-pulp process. An experimental research program has investigated the use of a variety of different types of resins for the recovery of gold, but to-date no resin studied has the desired properties of high selective loading capacity for gold cyanide and a simple inexpensive elution procedure. In addition very little is known concerning the physical strength of resins and their ability to resist shattering due to osmotic shock during cycles of adsorption and elution. The ability of ion exchange resins to enhance the leaching of refractory and re-adsorbing ores has not been investigated. This paper highlights the necessary factors that need to be addressed before commercialisation of ion exchange technology for gold extraction is feasible.

Jan 1, 1998

From depths of 400 - 600 m, coal is transported by a conveyor in a drift or a bulk winder in a shaft, whilst men and/or materials are transported by a slope hauler or a cage winder. Assessment of the effect of alternative combinations on the key cost factors - output, capital, labour cost and construction time - allows the optimum choice for particular circumstances, there being no uniform solution.

Jan 1, 1976

By D R. L Vedoy, L Botha, S P. Gumfekar, J B. P Soares

Most of the known in-place reserves of oil sands are found in Canada. These oil sands ores are mined using various processes to extract bitumen. The by-product slurry resulting from the extraction process, known as tailings, is discharged into tailings ponds. Fine kaolin clays are an important ingredient of the tailings because they remain suspended in water for many years. Current polymeric flocculation/dewatering technologies use acrylamide-based polymers such as polyacrylamide (PAM), but sediments produced using PAM-based flocculants hold considerable amounts of water due to the formation of loosely-packed flocs. Anionic polymers are better flocculants due to bridging and the charge-neutralisation mechanism. In this paper, we will compare the synthesis of two flocculants: thermosensitive, anionic flocculants and thermosensitive, hydrophobically modified anionic flocculants. The first flocculant is a copolymer of acrylic acid (AA) and N-isopropyl acrylamide (NIPAM), in which AA is the anionic monomer. The second flocculant is a copolymer of NIPAM, AA and the hydrophobic monomer N-tert-butyl acrylamide. We evaluated the dewatering efficiency of 2 wt per cent kaolin using both flocculants by comparing settling rates at different flocculant dosages, charge neutralisation ability and supernatant clarity. To better understand floc formation, we measured the floc size formed by both flocculants at different flocculant dosages. We propose that the hydrophobic monomer in the terpolymer flocculant helps expel water out of flocs, ultimately decreasing the water content in the sediments.CITATION:Gumfekar, S P, Vedoy, D R L, Botha, L and Soares, J B P, 2015. Thermosensitive, hydrophobically modified anionic flocculants for dewatering kaolin clays, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 45–50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By Gostylla W

The economic feasibility of controlled district cross-cut recirculation is examined in this paper with particular reference to the most important mine ventilation network parameters. An algorithm is developed to express the annual cost of recirculation which is then compared to the annual cost of conventional ventilation using the University of Queensland Experimental Mine as a case study. The concepts of resistance ratio and volumetric efficiency ratio are introduced and used to analyse the economic feasibility of controlled recirculation within a mine ventilation network.

Jan 1, 1988

By Eyers G. C

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

By M Parcell

"Ventilation risks in an underground mine have essentially remained the same for centuries, yet theevidence suggests that there are many coal mines that have failed to adequately control these risks.The conduit for the knowledge learned by previous generations exists in the mining legislation. In an ideal world, mines would not need legislation to tell them what to do; they would resolve the risks to an acceptable level so as to protect the safety of persons in the mines based on the acquired knowledge. There will be some who have been personally aff ected by a mining disaster but for the majority they will be remembered as a vague recollection of an event from long ago. The mining legislation is the repository for the knowledge and outcomes from inquiries of past disasters. The challenge for the current generation, and the generations to come is to appreciate the legislation that exists, so as to not ælearn the hard wayÆ. In reviewing most disasters there is comment or discussion on the adequacy of the legislation, which ultimately results in some amendment to the law. For each person, there is an increasing responsibility to ensure that the same mistakes are not repeated. Understanding the legislation, its history and its purpose is the fi rst step in ensuring thatventilation risks are eff ectively managed. Failing to do this will be disastrous. This paper discussesthe relevance, importance and potential pitfalls of coal mine ventilation regulation."

Jun 1, 2012

Two significant TBM boreability predic- tion models are outlined. Predicted advance rates are compared with actual advance rates taken from twenty case histories. The results show that a simple low cost method that uses one machine parameter and one rock parameter compares very favourably with a high cost sophisticated method which also includes information regarding discontinuities in the rock mass. The effect of rock texture on drillability is also examined. A method of quantifying rock texture has been developed and is outlined. Experimental results show that the developed TEXTURE COEFFICIENT returns highly statisti- cally significant correlations with drilla- bility data in a wide range of rock types.

Jan 1, 1987

By Linkson PB

The presence of residual cyanide in mine tailings and fill sands may, under specific circumstances, lead to acute and/or chronic cyanide poisoning of the environment and individuals. In this paper, the nature of cyanide contained in mine tailings is discussed, along with the circumstances under which such cyanide would become a hazard. A number of methods for cyanide degradation are reviewed in the paper, with special emphasis being placed on biological degradation (due to its low costs and the non toxic nature of the degradation process itself). Recommendations are made as to the best methods of setting up a biological degradation system, for use in mining Situations.

Jan 1, 1987

This paper examines the cost and economic consequences of varying a number of key factors in the course of developing and operating new underground longwall coal mines with both shallow and deep cover in New South Wales. The economics of the project are assessed for the first 20 years of mine life using the discounted cash flow method with produc- tion and selling price being determined to provide break even costs for a range of minimum rates of return.

Jan 1, 1988

By Williams RE, Ralston DR

Acid mine drainage is a serious environmental and economic concern, resulting in regulation of the mining industry and significant water treatment costs. An interdisciplinary approach is needed to analyze the many aspects of a complex acid drainage problem. This paper describes the integrated application of techniques from the following fields to the characterization of acid drainage at a large underground lead-zinc mine: 1) hydrogeology, 2) surface stream analysis, 3) structural analysis of fracture distribution, 4) hydrochemistry, 5) geostatistics, and 6) multivariate statistics. The Bunker Hill Mine in northern Idaho, is developed in highly fractured and faulted quartzites and discharges 95 L/sec of water with an average pH of 2.8 and an average zinc concentration of 120 mg/L. Research has been conducted on all aspects of the acid water production and drainage problem. Recharge to the mine has been investigated using geophysical techniques and tracer studies. Fracture mapping and geostatistical analysis of the fracture data have been used to determine characteristics of inflow to the mine workings. Hydrograph analysis techniques have been applied to water flow data within the underground workings. Chemical sampling and analysis have been used to identify acid producing workings, and better understand mechanisms controlling acid water production. Multivariate statistical techniques have been applied to analyze the quality and flow data. Research results from the many subprojects of the Bunker Hill study reveal the importance of an interdisciplinary approach to the analysis of acid mine drainage problems.

Jan 1, 1988

By F Palkovitz, S Wilson, F Felipe

The management of waste from mining operations is a significant aspect of bringing a mineral commodity to final market. The ore beneficiation process and transport/disposal of waste involves significant consumption of costly resources. A number of options exist to dispose of mill waste on surface and as a backfill material. These range in complexity, risk, capital cost, operating cost and ultimately business performance. This paper discusses the value delivered to a business in using dewatering systems including paste as opposed to conventional slurry tailings disposals. This is illustrated through various case studies and serves to demonstrate how paste can add value and reduce risk to a successful business.

Jan 1, 2009