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By Hargraves A. J

With increasing depth, stresses and stress phenomena are becoming more important considerations in Australian coal mining.A large number of compressive and tensile strength tests was made on coal and rock cubes cut from samples taken in various Australian collieries. In addition, an empirical impact strength test was carriedout on fragments of the same samples, to obtain a correlation with compressive strength.In one colliery, flat-jack measurements were taken to assess stresses in coal ribs and in the roof.INTRODUCTIONBy world standards, some of the New South Wales collieries are approaching depths of cover considered a maximum for bord and pillar the normal Australian coal mining method. Several South Coast collieries are winning coal at depths of about 1500 ft., and future operations are being planned at deeper cover. Some areas of these deep workings produce considerable quantities of seam gas.Phenomena associated with high stress and copious gas under pressure in the seam violent phenoma presenting a danger and a nuisance in mine working - have occasionally occurred, and the phenomena are being investigated as a whole (Hargraves, 1958), and separately as a gas problem (Bolt and Innes, 1959; Hargraves, 1962) and as a stress problem. This paper relates to the latter - to investigations into the strengths of coals and coal measure rocks, and into the stresses in and about coal seams...

Jan 1, 1962

By D Feng, G C. Lukey, J S. J, R R. Dagastine

An ongoing challenge in the coal industry is pyrite removal using the flotation method for fine particles. The use of a æseparation in frothÆ (SIF) technique to recover coarse particles of up to a few millimetres in size has presented a potential solution. However the commercial success of SIF is still limited due to the poor understanding of the separation mechanism. The particle floatability in SIF is determined by the constructive or destructive stresses resulting from the forces exerted by the particle on the bubble films. Hence, the surfactant properties and the mineral characteristics (eg hydrophobicity, shape, etc) are the key factors that control the interaction between the particle and froth. In the present work, the interaction forces between different particles (ie crushed glass, pyrite and coal) and a single air bubble are measured in a non-ionic surfactant solution (pentaethylene glycol mono n-dodecyl ether, C12E5) using an atomic force microscope (AFM). Experimental results show that the interaction is primarily dependent on the contact angle (ie the degree of hydrophobicity of the minerals). For crushed glass, the transition from repulsion to attraction was observed as the contact angle increased. As the concentration of C12E5 increased, the adhesion force was suppressed due to wrapping effect. For coal and pyrite with much higher hydrophobicity, long-range attraction was observed. The effect of shape factor was only visible at high surfactant coverage where sign of destabilisation became noticeable on the retracting force curve. These results provide a fundamental understanding of the direct interaction forces of a complex real system between an irregular particle of either crushed glass, pyrite or coal and a single air bubble. Theories developed for interpretation and modelling are thus far based upon the study of ideal systems of glass or polystyrene spheres and an air bubble and were incapable of explaining the interactions in complex real systems. The presented measurements were a first approach to the problem of real mineral-bubble interaction in flotation systems. Thus, the results can only best be interpreted semi-quantitatively.

Jan 1, 2005

The original leases making up today's North Kalgurli Mines were developed by independent companies on an ad hoc basis. The major disadvantage which now arises is the varying levels of mining horizons. From Kalgurli Shaft in the south, through main Shaft and to Croesus Shaft in the north, there are three separate sets of levels. work has commenced to link the three areas with either common levels or new development which will facilitate common access and haulage via Main Shaft.Generally, the workings at North Kalgurli were established at the turn of the century. The introduction of techniques and equipment to bring the mine into the 20th Century has been difficult and slow. The general size of openings, a widespread workforce and complex ore distribution often make innovation and change more than a challenge.

Jan 1, 1985

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

Jan 1, 1994

By D Millette, F Gay

Surface tailings are finely ground waste materials produced in all mines after the mineral or metal has been removed from the metallurgical process. Current methods for disposal of tailings involve constructing dams, dumping into existing waterways, and depositing as backfill underground. Each method has its drawbacks in terms of cost, level of complexity, safety and environmental concerns. Backfilling is the process whereby waste material (generally metallurgical tailings, prepared aggregates or a combination) is placed from the surface back underground into open mine workings via conveyor belts, hydraulic or pneumatic pipes or gravity. In the backfill process common difficulties are expensive placement costs, equipment wear and the ability to meet early and long-term strength requirements. Traditional tailings transportation in pipes involves the use of water as the transport medium. Foam technology involves the introduction of micro-air bubbles that replace the water as the main transport medium. This air can be removed after placement if necessary, by the addition of a defoaming agent. This could produce an under-saturated stable cake. Foam technology has the potential to revolutionise surface tailings disposal and backfilling by providing a less expensive and environmentally safe alternative to those just described.

Jan 1, 2000

Roadheader tunnelling machines have been used in Australia by both mining companies and contractors involved in the mining and con- struction industries since the early 1970's. They have both advantages and limitations, and this paper discusses machine excavation from the point of view of a contractor who has both reaped the benefits and suffered the conse- quences of using roadheaders. The paper also includes brief descriptions of three projects tackled by roadheader, all the projects being Declines.

Jan 1, 1987

This paper reviews the various processes successfully in operation to treat refractory gold ores and describes in detail the alkaline pressure oxidation circuit operating at the Barrick Mercur Mine, Utah, U.S.A., on car- bonaceous/sulphide refractory ore and the acidic pressure oxidation circuit operating at the Barrick Goldstrike Mine, near Carlin, Nevada, U.S.A., on sulphide refractory ore. The autoclave process is important to Barrick for the extraction of gold. The Company has operated successfully a 750 ton per day unit at its Mercur property for the past two years and more recently has commissioned a 1500 ton per day unit at Goldstrike. The paper presents data relative to operating costs, materials of construc- tion for autoclaves and peripheral equipment, reagent requirements, and changes required during commissioning for both autoclave systems.

Jan 1, 1991

By K Seddon

Segregation of tailings on deposition can occur as a result of a) sub-aqueous deposition, and b) sub-aerial deposition at lower solids concentrations (i.e. when the solids concentration is less than the segregation threshold). The effects are likely to be more pronounced in the case of subaqueous deposition.This paper presents the results of an investigation of a sub-aqueous tailings facility.Data from the investigation show extreme variations in particle size and density compared to test results for non-segregated ‘all-in” tailings. The results indicate that on segregation both the fine and coarse splits tend towards a well sorted (poorly graded) mix, and both have significantly lower consolidated density than the all in tailings. This result is reasonably well known for the case of the segregated fines (“slimes ponds”) but less appreciated for the coarse fraction. The results suggest that if the effects of segregation are not allowed for, the overall density of the deposit can be seriously over-estimated at the design stage. Also the quantity of water retained in the tailings can significantly influence water recovery and water balance results.CITATION:Seddon, K, 2018. Segregating tailings – effects on density and water retention, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 299–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By F J. Rios

In the eastern high-strain domain of the Quadrilßtero Ferrffero, Brazil, hard and soft high-grade hematite ore may occur as schistose bodies in shear zones mainly related to the Cambotas-Fundpo thrust system. These orebodies are almost entirely constituted of oriented specularite platelets that develop both as a product of crystal-plastic deformation of hematite and solution-precipitation processes. Both mechanisms interact in the partitioning of the strain, while solution-precipitation is responsible for the precipitation of hematite and localised leaching of silica resulting in the formation of syntectonic ores. The analyses of fluid inclusions from specularite crystals of the Conceitpo and Timbopeba deposits, located in the northern and southernmost areas of the eastern high-strain domain of the Quadrilßtero Ferrffero, were studied using infrared microthermometry and Synchrotron x-ray fluorescence. The results indicate the participation of highly saline aqueous H2O-NaCl fluids containing other additional cations (Ca, Fe, K and probably Ti) in solution and homogenisation Temperature (Th) averaging between 130¦ - 190¦C. However, the partial fusion of metastable saturation phases indicates crystallisation temperatures of approximately 400¦C. The mineralisation process produces high-grade orebodies as well as Fe-rich specularitic itabirites that are explored in that area. The shear zones are related to thrust faults mapped and interpreted as related to the PanAfrican/Brasiliano Orogeny that affected the Quadrilßtero Ferrffero, thrusting the Paleoproterozoic platform sequence of the Minas Supergroup over Mesoproterozoic quartzites of the Espinhato Supergroup. They intersect and even overprint an early metamorphic and tectonic fabric of Paleoproterozoic age (Transamazonian Orogeny). The geological and fabric relationships lead to the conclusion that the fluids involved in the mineralisation were most probably of external origin, of still unknown source (possibly igneous), during the closure of the Spo Francisco Craton.

Jan 1, 2005

By B Flynn, P Knights

Low-loaders or 'floats' for relocating equipment in surface mines are limited to a capacity of approximately 350 t. In the iron ore industry it is desirable to be able to rapidly relocate excavators in order to maintain production rates within appropriate quality limits. In addition, the ability to rapidly relocate heavy equipment raises the possibility of improving the quality of repairs by performing maintenance in controlled shop conditions. However, many iron ore operations operate hydraulic excavators in the 600 to 800 t range, with newly released excavator models exceeding 800 t. These excavators are too large to float using conventional technology. This paper examines the potential for using multi-bogie transporters to relocate large hydraulic excavators in surface mines. Recent innovations have seen the development of modular transporters which can be coupled together to achieve larger platform areas. When separated, and with their drive bogies neutralised, these units are able to be towed behind prime movers and relocated between mines via public roads. The potential cost savings for relocating a Terex RH170 excavator in an open pit coal mine are examined. In the first six months of 2008, the analysis showed the potential for a 38 per cent reduction in total travel time with a corresponding revenue increase of approximately $350 k. The paper recommends that a feasibility study be conducted into offering a heavy equipment relocation service within the Pilbara region.

Jan 1, 2009

By D Osborne

Current mineral extraction and valorisation activities still have a strong focus on the ‘delivered product(s)’ which might be a bulk commodity such as metallurgical coal, hematite, bauxite, etc., and mineral concentrates such as metal sulphides, oxides, and carbonates; precious metals, such as gold, silver and PGMs, REEs or battery metals; halogen salt forming elements; or industrial minerals, which are non-metals including crushed rock, sand, and gravel etc. With the current focus on tailings disposal the pushback has been to seek alternatives to the currently ‘conventional’ disposal method via increasingly higher risk tailings settling facilities (TSFs) with a changing focus towards ‘dry disposal’. Whichever option is selected, the alarming trend is the increasing cost and ESG impacts. An emerging approach is to pose a focusing question ‘Is there anything else passing into the tailings stream and/or disposable waste streams which could be recovered and pass into the product revenue stream? All of the above ‘primary’ process streams offer opportunities for increasing recovery and offsetting some of the disposal costs. Some secondary opportunities are already being pursued, such as REEs and battery metals from base metals deposits, but other opportunities are still being overlooked, such as building materials and soil conditioning pellets. These potential ‘new’ product streams can also utilise other mining and domestic wastes such as smelting slags, glass waste, plastic waste etc. This paper will address these opportunities and provide examples including process approach, economics and some of the current barriers that exist, which are holding back progress on such initiatives.

Sep 1, 2024

By R Polmear, G Mauger

You wouldnÆt start excavating before testing core samples, so why would you approve a project plan before all factors have been identified, reviewed and addressed? Even a champion sports team made up of the best players canÆt produce optimal results without a well understood and agreed game plan. Could an F1 racing team produce their outstanding performance without rigorous evaluation and testing of the factors for successful performance? Why would we expect a capital works project team to be able to get it right without an understanding and an involvement in setting and implementing the overall game plan and without an understanding of all stakeholder requirements? For International PowerÆs Hazelwood (IPRH) mine in Victoria, the challenge was development and delivery of a 40 year mine plan, ultimately involving relocation of existing mine operations into an adjacent new coal field, land acquisitions and major environmental and other approvals to allow diversion of three streams, a highway, an Over Dimension route and other infrastructure in a political and environmentally sensitive atmosphere. The lessons from International Power HazelwoodÆs (IPRH) experience are: that the clear set of project principles and guiding values ensured delivery of a robust plan; a robust plan can withstand significant change; and value management (VM) played an important role in providing assurance, to all, that the plan was sound at both the strategic and micro levels. This Hazelwood mine project included five major VM workshops. The first was a critical review process in addition to design and cost reviews. This VM workshop was used to analyse, at a high level, the preferred coal mining sequence and design concepts, together with the interaction between design elements, risks and costs. In addition to this, the workshop provided an agreed common pathway for all downstream decisions. A second VM study was conducted to ensure that the proposed plan and design for relocation of the conveying systems from the existing mine into the new field were planned for optimum achievement from a whole of life cost, time, operational and maintenance perspective, plus the logistics of continuing operations while relocating assets. A third study followed to review the Conveyor Transfer Alliance and review functional design. A fourth VM study workshop was formed at the start of Phase 2 Alliance to ensure that the best value for money was being achieved through the current design, schedule and project arrangements and that all interfaces between parties had been reviewed and responsibilities were clear and understood. Other studies are outlined later in this paper. This paper details the evaluation criteria and processes used in the project evaluation that led to the WestField Mine Development.

Jan 1, 2007

Taxation is a major factor in evaluating mining project developments. The availability or otherwise of effective tax relief for project expenditures can have a crucial bearing on the decision to proceed with a project. The special position of the mining industry is recognised within the Income Tax Assessment Act (the "Tax Act") by special legislation, namely Divisions 10, 1OAAA and 10AA. The legislation both extends the scope of items which are eligible for deduction and affects the timing of deductions. Generally, the legislation separates expenditure into 3 categories: 1. Expenditure on exploration 2. Capital expenditure on the development and the running of the mine; and 3. Facilities used in the transport of minerals. Companies evaluating a project should carefully analyse their proposed expenditures, allocating them between these categories so as to identify potentially non-deductible expenditures and to determine the period over which tax relief will be Obtained.

Jan 1, 1983

By A Struminski

The principles of occupational risk evaluation resulting from the improper ventilation of the underground mines were presented. It was shown that the risk level implies the appropriate planning and usage of prevention methods. That approach is fundamental in the ventilation, fire and climate safety management in the copper ore mines. The paper uses the adequately modified Risk Score method.

Jan 1, 2003

By M Dietrich

The paper describes an efficient method for analysing the different attachment kinematics of excavators and other linkages by taking into account digging forces, the workspace and the stability of the machines. The different attachment kinematic systems of hydraulic excavators and a æclassical analysing methodÆ will be presented. The method was integrated as a plug-in for the multibody simulation (MBS) software MSC.ADAMS to create an easy to use solution for design engineers. A comparison of the new MBS-solution with the classical static analysis is a part of this paper and shows the advantages of the new method. This takes into account the manifold and new dynamic analysing opportunities, as well as more detailed models leading to more accurate results.

Sep 26, 2011

By Linge HG, Klauber C

The key element in the carbon-in-pulp process for gold processing is the loading of dissolved Au(CN)2 from solution onto activated carbon. The mechanism and kinetics of this step have been examined by solution adsorption-desorption and X-ray photoelectron spectroscopy for both coconut derived activated carbon and peat-based activated carbon. The results show that these carbon types have the same mechanism and kinetics of adsorption. There is no contribution to the bonding from carbon-oxygen functionalities on the carbon surface, as has been invariably supposed in all previous theories for the mechanism of the reaction. It is shown that Au(CN)Z is reversibly adsorbed intact on and parallel to the graphitic planes of the carbon with the formation of a weak carbon-gold n-donor bond. The kinetic measurement of carbon gold loading reactivity is discussed and use of the Murdoch equation for this test is critically assessed.

Jan 1, 1989

It cannot be said that accurate and reliable ore reserve estimation is the fundamental of any mining operation success. Estimation techniques which are used to estimate the grade distribution of an orebody together with the assessment of uncertainty and risk have a vital influence on the success of any optimisation algorithm. Traditional estimation techniques such as kriging or inverse distance weighting are frequently used for assigning grade values to blocks. Various attempts have been made in order to compare geostatistical estimated methods for ore reserve estimation. This paper aims to evaluate the sensitivity of different estimation methods over changing the block dimension. For this reason, several block models with different dimensions were derived in Chador Malu iron ore mine which is located in 180 km northeast of Yazd in the centre of Iran. Each block model was estimated by different estimation methods such as nearest neighbours (NN), inverse distance (ID) and ordinary kriging (OK). The results of each estimation methods were compared against a control block file created by using the assay results of all blastholes drilled in the ore over four benches of the pit. The results signify that by estimating the large block size, no significant improvement occurred due to the employment of different estimation techniques. Furthermore, the grades estimated based on ID method is more reliable, but OK methods estimated more accurate tonnage.

Dec 6, 2010

By Roberts W. P H, Chant R. A

Investigation of the "whole-rock" major element geochemistry of the Broken Hill lodes and of the rocks immediately enclosing them has been carried out on the full lengths of 19 diamond drill cores transecting B lode,A lode, No. 1 lens and Lead lode in The Zinc Corporation Ltd.-New Broken Hill Consolidated Limited, at the southern end of the line of lode.It appears that the abundances of all of the principal "non-sulphide components" - Si02, AI2O3, Ti02, CaO, MgO, MnO, K2O, TiO2 and P203 - are closely tied to the incidence of sulphide. The well-known direct relationship of calcium and manganese with the incidence of sulphide is confirmed, and to this is now added the pairing sulpnide-phosphate, which is particularly welldeveloped in the zinc lodes. It is also now shown that there is a clear inverse relationship between sulphide on one hand and AI2O3, Ti02 , MgO, and K2O on the other.Total Fe-which is an important constituent of both sulphide and non-sulphide-appears to occur in essentially similar amounts in ore and enclosing materials. The incidence of Na20, while generally depressed in ore, issomewhat erratic and equivocal. Si02 and sulphide usually show a highly systematic inverse relationship-a feature stemming inevitably from their being by far the two most abundant, and hence two co-dominant, materials ofthe ores.These features of elemental abundance are interpreted in the context of seaflooor hydrothermal ore deposition to give some insight into the amount and nature of detrital and of chemical sedimentation, the formation and accumulation of different clay minerals, the chemical and physical characteristics of the bottom waters, and the reasons for the comparative paucity of iron in the Broken Hill lode.

Jan 1, 1978

Papua New Guinea has a long history of mining, with gold being produced from deposits on islands in the south east of the country over a hundred years ago. Before the Second World War, the mining and dredging of gold made the Wau-Bulolo area a

Jan 1, 1994

The Australian Mineral Industry has to compete on world markets, so its mineral research has to be aware of overseas developments, it must be of world class, and it must utilise as many ideas as possible in order to solve those problems that uniquely affect Australian minerals processing. North American mineral and resource research may be taken as a guide to world government, industrial, contract, and entrepreneurial research trends and ideas. A number of interesting findings are noted that may guide Australian developments and strategies for the future, in minerals research and exploitation.

Jan 1, 1986