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By G McMillan, P Mulvey

"Geochemical characterisation is done based upon the geology and metallurgical batch testing prior to commencement of the operation of the plant.  Tailings repository design is based upon geochemical assessment of the waste material, as well as the geomechanical issues associated with storing the waste. The resultant conceptual and detailed design is incorporated into the environmental impact statement (EIS), upon which mine approval is based. The entire environmental monitoring and harm mitigation program, which is usually a condition of the Mine Lease approval, is based upon the applicability of the original characterisation.Tacit to this process is that there is no change in the geochemistry of the tailings, i.e. no change in the implications for acid & metalliferous or saline/neutral mine drainage (AMD/SNMD) generation. But any changes in milling and processing can have a substantive impact on the geochemical behaviour of the tailings metallurgy, and potentially render an operation non-compliant within the conditions of the mine license.Environmental and statutory approval implications for continuous improvements of metallurgy need to be understood because unintended consequences could cost more than the benefits of the improvement, and in some cases cost more than all the profit made from the mine.  Examples uncovered during audit and consultant practice will be presented together with a process to ensure implications for adverse environmental harm and license conditions are fully considered.*This paper is only available for individual download. It is not included in the conference proceedings*CITATION:Mulvey, P, 2013. Continuous improvement - how changes in metallurgy can have a substantive impact on environmental impact and closure - lessons learnt from environmental auditing, presented to MetPlant 2013 Conference (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By J Addai-Mensah, M Adam, W Skinner, J Begelhole, K Quast

Granulation of iron ore fines into robust granules is critical to successful sintering and blast furnace operations in iron and steelmaking. Iron and steelmakers desire iron ore granules with high strength, uniform size distribution and low fuel consumption to enhance efficient sintering operation. Unlike hematite ore, magnetite concentrates do not granulate easily at low binder dosage to yield coarser granules due to the absence of nucleus particles. This motivates the present study to harness the complementary properties of hematite ore to enhance granulation of magnetite concentrates via blending. The current state-of-the-art in hematite and magnetite blend granulation is reviewed, along with granule property limitations. Preliminary experimental work on granulation of hematite and magnetite blends as a precursor to sintering is reported.CITATION:Adam, M, Addai-Mensah, J, Begelhole, J, Quast, K and Skinner, W, 2017. Enhancing magnetite concentrate granulation by blending with hematite ore, in Proceedings Iron Ore 2017, pp 17–24 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By A Duran

When dealing with rocks in the geotechnical profession, a common activity involves providing an estimate of the intact strength. The tactile approach and descriptions of strength that apply to soils is well documented, can be readily checked through the use of a pocket penetrometer and are known to provide reliable estimates of strength. Moreover, although different soil strength classification systems are present, the bounds between classification classes are compatible across almost all documented classification systems. However, this is not the case for rock strength materials. There are numerous systems within the literature, some with different concepts, and almost all have different bounds to each strength classification. In this paper, the author presents seven classification systems for estimating intact rock strength and highlights issues in their implementation. Example cases are presented to discuss the typical concerns confronting field strength estimates.CITATION:Duran, A, 2014. Comparison of field estimated strengths, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 101–106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By D O’Dea, B Godel, T Honeyands, G Evans, T Harvey

The pores within iron ore sinter are important for producing a high quality material that is strong and easily reduced. The complementary methods of mercury intrusion porosimetry (MIP) and X-ray computed tomography (CT) were used to characterise the structure of industrial and pilot scales sinters across a wide range of pore sizes (3 nm to 100 µm for MIP and 50 µm to 5 mm for CT). The inhomogeneous nature of sinter and the variation in the measurements make it difficult to compare samples. The generalised additive modelling (GAM) approach, using the open source statistical software package, R, has been applied to highlight where there are peaks in the concentration of pore sizes. Importantly, the shape of the GAM-fitted function and the heights of the peaks show statistically significant differences between samples. For the samples investigated, the GAM-fitted functions for the MIP volume distribution of pore diameters were found to have a common set of distinctive peaks at 0.005, 0.6 and 20 µm. The GAM approach was also applied to the X-ray CT measured pore wall thickness, highlighting a single peak whose position varies between samples. The cause of these distinctive peaks and their implications for sinter quality are discussed. Correlation was found between the volume in peak 1 (0.005 µm) and the concentration of primary hematite. No correlation was found between the pore wall thickness and the strength of the sinter, suggesting the composition of the pore walls may be more important. Future work will focus on small-scale sinters produced under tightly controlled conditions to study sinters with a wider range of quality values.CITATION:Harvey, T, O’Dea, D, Evans, G, Godel, B and Honeyands, T, 2017. Highlighting key features of the pore structure of iron ore sinter using mercury intrusion porosimetry and X-ray computed tomography, in Proceedings Iron Ore 2017, pp 39–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Improved roof control in high deformation tailgate environments has been achieved over the last decade through development of stiffer and increased capacity standing support products. æThe CanÆ is one such development, being a steel cylinder containing a weak cementitious fill, designed to essentially fold in upon itself whilst maintaining strength. A laboratory study to better define the relative load contributions of the steel cylinder and fill, the confining interaction between these components and most importantly, the potential impact of varying the steel and/or fill properties is described. This would enable the support engineer to ædial-upÆ the desired strength and stiffness properties and optimise the standing support design with respect to load capacity, stiffness, weight (handling) and cost. Design curves to optimise strength based on steel casing thickness, fill strength (confined and unconfined) and æCanÆ geometry were established. Scaled-down (one-third) samples were used in the test program and found to adequately reflect the loading behaviour of full-scale versions, thereby providing significantly greater scope for further product development at less expense compared with testing full-scale products.

Jan 1, 2005

THE Taranaki oil-field is situated on the western side of the North Island of New Zealand, at about its widest part, and may be said to be the most compact and fertile part of the Dominion, for, with the exception of the upper half of Mount Egmont and of the ranges adjoining, which absorb 36,000 acres, the whole of the area, minus what is taken up by the rivers and streams is suitable for settlement, and certainly two-thirds is good land. The gross area of the district is 2,417,299 acres. The principle rivers are the Wanganui, Mokau, Waitara, Patea and Waiwakaiho. Mount Egmont, which is 8260 ft. high, used to be called Taranaki, and from it the district takes its name (the Maori meaning of which is "sloping peak ").THE OIL-FIELDThe discription of an oil-field now-a-days usually resolves itself into a mass of figures and statistics, of great interest and value to the engineer and commercial man, but practically indigestible to the general public. It is the realm of the financierand the captain of industry.

Jan 1, 1912

By A L. de Ambrosis, S J. Clarke

In the non-codified realm of tunnel design there are issues which are sure-fire instigators of controversy. This paper presents a discussion regarding one particular issue which in the authors’ experience often results in comment and debate. This issue only forms part of the rock load assessment process, but it is specifically addressed with the intention of presenting a rational basis for design, which may result in broader acceptance within the tunnel design community.The issue considered relates to the characterisation of in situ rock stresses for the design of tunnel support in the Sydney Basin. A summary is given of the literature on the topic, with emphasis on the main sources of uncertainty and contention. A design approach is proposed, with particular focus given to the numerical modelling of in situ ground stresses and the approach used to ensure that the adopted stress regime is consistent with the assumed ground model. The resulting variability in the initial stress field is discussed and comparisons made to the test database.CITATION:de Ambrosis, A L and Clarke, S J, 2014. Characterisation of in situ stresses for tunnel lining design in the Sydney?Basin, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 247–252 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

Holla has given a good background to the various methods of subsidence control in the coalfields around Sydney.The present writer notes that in many cases, especially with wide longwall panels, there is not the flexibility to alter the mine layout as there is to some degree with the various pillar extraction methods. For this reason it may not be possible to plan the workings to minimise subsidence and some damage to structures may occur. The cost of repair or the cost of subsidence provisions to minimise damage may be small in relation to the tonnages of coal which would otherwise have to be sterilised. One method of subsidence control which has been in use in the Newcastle area since 1970 is the panel and pillar layout (partial extraction layouts with stable pillars). An extracted panel width of 0.6 times the depth of cover resulted in a maximum subsidence of 115 mm for an extracted seam thickness of 2.2 m.As Holla points out, the extracted panel widths in relation to th depth of cover depend on the particular geological setting. His Fig. 3 shows that the subsidence over a panel width of 0.3 times the cover depth in the Southern Coalfield is the same as over a panel width of 0.55 to 0.6 times the cover depth in the Northern Coalfield.Selective pillar extraction and longwall mining can both be used in the panel and pillar layout. Holla's Figs 2 and 3 are used to estimate the maximum subsidence over an extracted panel of known geometry. Maximum subsidence is related to seam thickness. What provision is made for a reduction in subsidence due to the coal which remains behind in a pillar extraction panel if the pillar recovery is poor? The writer suggests that an effective seam height could be used, based on the actual mining height reduced by a factor to account for the percentage recovery of coal from an extracted panel.

Jan 1, 1986

Water quality standards for some of the substances likely to be discharged to natural waters by the mining industry are discussed. After briefly examining how uses of water can be affected by discharges, standards for suspended solids and turbidity, pH, and toxic materials are considered. Heavy metals are examined in some detail because of recent public concern regarding their discharge. Caution is given in connection with their analysis at the very low concentrations required for management of natural waters. Finally, the issues of what constitutes a water right concentration compliance breach, and the appropriateness of biological monitoring as a condition on a water right are raised.

Jan 1, 1986

By K Niiranen

Luossavaara-Kiirunavaara AB (LKAB) operates one iron ore mine, three concentration plants and three pelletising plants in Kiruna, Sweden. The current methods of separation at the beneficiation plants are low intensity magnetic separation (LIMS) and reverse apatite flotation, where the wet LIMS stage is regarded as the crucial part of silica separation from the ore. Because future silica levels are expected to increase in the incoming material to the beneficiation plants, geometallurgy has become an important area of development and research.A laboratory-scale methodology was developed for the systematic characterisation of the ore for mineral processing, with the focus on the high silica ore type B2 and newly discovered subtypes. This methodology combines mineralogical, geochemical and process mineralogical characteristics. Automated mineralogy (QEMSCAN®) is used to study the modal mineralogy, the distribution of silicate minerals in different particle size classes after comminution, the deportment of silicon (Si) between various silicates and the degree of liberation and intergrowth of magnetite and silicates. An essential stage in the systematic characterisation of the ore deposit for mineral processing is the estimation and simulation of different parameters from the laboratory scale to the full scale at the concentration plants. This is achieved by using empirical models based on the data collected at the mineral processing plants. As the first step to implement the geometallurgical information, the current geological model is reconstructed with the mineralogy and the two, newly defined subtypes of high silica ore type B2 are separated into different domains.To study the reduction of the SiO2 content in the magnetite concentrate, a large-scale reverse cationic silicate flotation laboratory test program was initiated in early spring 2016. This program investigated potential silicate flotation in the beneficiation plants at the Kiirunavaara site. The second target is to implant mineral processing parameters into the block model based on the new geological model. This information provides a good basis for making a prognosis for mine planning and a quality prognosis regarding the crude ore for mineral processing.CITATION:Niiranen, K, 2017. A geometallurgical perspective on a high-grade iron ore deposit at Kiirunavaara, northern Sweden, in Proceedings Iron Ore 2017, pp 309–318 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Crocidolite deposits in the Hamersley Ranges, NW. of Western Australia, occur over a length of 180 miles and a width of 20' to 30 miles. Their stratigraphic environment and mineralogy is comparable to that of similar deposits of the Cape Belt, South Africa. It is probable that the known exposures' represent only a small portion of the total extent.Current production is wholly by Australian Blue Asbestos Pty. Ltd. at Wittenoom Gorge and has been in the order of 1,2,000 to 14,000 long t.p.a over the past six years.INTRODUCTIONThe Hamersley Ranges are located in the NW. Division of Western Australia and extend, approximately, from latitudes 21° 30' to 23°S and longitudes 117° to 1200 E. Their mean height above sea level is 2,000 ft, and they rise from 600 to 800 ft above the general level of the tableland which extends SE. from the coastal town of Roebourne.Mt. Bruce, the highest peak, is 4,024 ft above sea level. The ranges are intersected by numerous north-flowing streams, which are dry during the greater part of the year. These streams have carved deep gorges, and it is in these that the principal deposits of crocidolite outcrop.The presence of the mineral was first recorded in 1917, but the deposits remained untouched until 1937 when strong market demand for crocidolite resulted in considerable prospecting and mining activity, particularly in Yampire, Wittenoom and Dale's Gorges. It was established also that the blue asbestos belt extended from Willi Wolli Springs NW. to Millstream station, Le., over a length of 180 miles and a width of 20 to 30 miles. A number of attempts were made to develop and treat the Yampire and Wittenoom...

Jan 1, 1964

The variation of carbon monoxide and hydrogen utilization with the amount of the reductant in the blast furnace bosh gas was investigated for the No. 4 blast furnace at The Broken Hill Proprietary Co. Ltd.iron and steel works. Newcastle. The degree of CO utilization decreased with increasing CO in the bosh gas; the H., utilization increased with the H., content of the gas. Empirical relationships for CO and H., utilization are proposed.H2, is 3-6 times as effective a reductant as CO at present levels of CO (34-39 per cent) and H2 (6-10 per cent) in blast furnace bosh gas. H2, gas injection into the blast furnace is proposed as a means of lowering the coke consumption, and the economics of H2 injection are evaluated.

Jan 1, 1975

Statistics on the imports of industrial minerals into the EECshow that the traded volume in 1987 is approximately 23 million tonnes.The following table documents the imported quantities on the most important industrial minerals.

Jan 1, 1989

By L R. Sousa, M He

Rock burst is common in deep underground excavations and is characterised by a violent ejection of block rocks from excavation walls. It is critical to understand the phenomenon of rock burst and particularly the failure mechanism. Laboratory experiments are one of the ways. For that purpose, a rock burst laboratory test system was developed at the State Key Laboratory for Geomechanics and Deep Underground Engineering at the China University of Mining and Technology, Beijing. A true triaxial test system, designated the Deep Underground Rock Burst Analogue Test Machine, was developed, which can transfer a stress state from three-direction-compression on six surfaces to the compression on five surfaces with one set free. The rock burst experimental system comprises an acquisition of acoustic emission signals, a high-speed recording in order to accurately record the kinetic characteristics of rock fragments ejected during a rock burst event and the possibility of infrared thermography showing the surface temperature of the samples. In this paper, analyses of typical results from rock burst tests are presented with a description of the obtained results. The mechanisms of rock burst are illustrated, and a rock burst classification is proposed based on these laboratory tests. For the control of rock burst, the constant resistance, large deformation (CRLD) bolt or anchor is presented for accommodating the large displacement of surrounding rock masses and absorbing the impact of the sudden release of rock burst while outputting a constant resistant force in response to the external load. The CRLD bolt or anchor has had practical applications in underground mines. Finally, in situ tests performed in a tunnel at Qingshui coalmine, China, are analysed in detail.CITATION:He, M and Sousa, L R, 2014. Experiments on rock burst and its control, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 19–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By C Haughy, F F. Pitard

Blue Mountain Minerals is a large supplier of calcium carbonate products used by various manufacturers as a major raw material. Very small amounts of free carbon in the rock can have a huge impact in carbon-sensitive applications. The marble in the deposit at Blue Mountain Minerals contains variable amounts of free carbon in the form of trace amounts of the mineral graphite.To make quality improvements, variography was used to measure the impact of non-ideal sampling practices at the Blue Mountain Minerals operations in Columbia, California in the United States. A major investment in correct sampling systems and sampling protocols was implemented over a one-year period. Subsequent variography was used to measure the improvement on the predictability of the graphite content in marble produced by the quarry and as it is processed as an acceptable raw material for extremely carbon-sensitive applications. The improvements of the sampling protocols, control of long-range changes and better knowledge of process cycles are easily noticeable on variograms when they happen to exist. The economic impacts are discussed.CITATION:Haughy, C and Pitard, F F, 2017. Use of variography to measure improvement of sampling practices for the quality control of graphite consistency in marble used for carbon-sensitive applications, in Proceedings Eighth World Conference on Sampling and Blending , pp 255–260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By F Linares, B De Waele, K Bischoff, M Lacorde, G Loveday

Recent exploration has identified the presence of detrital iron deposits (DIDs) associated with banded iron formation (BIF) units in the north-west of the Congo Craton, Gabon. The regional geology comprises a complex of granitoids and gneisses assigned to the Archaean Chaillu Complex, within which older slivers of lower amphibolite-grade greenstones are preserved including muscovite-biotite-garnet-bearing felsic schist, amphibolite and BIF. These units are typically overlain by several metres of residuum comprising colluvium, eluvium and duricrust. The residuum is overlain by a regionally extensive loess cover from 2 m to 10 m thick.The DIDs occur within the weathered residuum as mostly unconsolidated gravels with lesser canga (CAN) duricrust draped over deeply weathered hematite. Head grades are in the range of 45 to 52 per cent Fe. Fresh BIF, located from 30 to 50 m below surface, is comprised of magnetite-quartz±amphibole. The detrital iron gravels are comprised of rod- and plate-shaped clasts of hematite (martite)-maghemite-goethite composition, in a ferruginous sand to clay-sized matrix. The DID form ridges and plateaus that coincide with magnetic highs defined using high-resolution ground magnetic surveys.The field relations and petrography indicate that the detrital iron accumulations are the result of weathering (including enrichment) and erosion of primary BIF. This includes removal of quartz, further oxidation and re-cementation of BIF to form ferruginous caprock. This cap and the in situ oxidised BIF were subsequently disaggregated and liberated, and further weathered to form the detrital iron accumulations.Metallurgical test work on bulk detrital iron samples has shown this material can be upgraded to lump and fines iron ore products with grades of 62 to 65 per cent Fe using simple scrubbing and wet screening, followed by dense media separation of the -1 mm fraction, with overall mass yields from 75 to 85 per cent. The test work indicates a high ratio of lump to fines products, sometimes exceeding 50:50.CITATION:De Waele, B, Lacorde, M, Bischoff, K, Loveday, G and Linares, F, 2017. Geological and metallurgical characteristics of banded iron formation associated detrital iron mineralisation in Central West Africa, in Proceedings Iron Ore 2017, pp 259–268 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By P Fullagar

Automated multi-sensor core loggers (MSCL) measure petrophysical properties of diamond drill cores, including gamma density, P-wave velocity, electrical conductivity and magnetic susceptibility. A Geotek MSCL system has been used to record petrophysical data on archival drill core from Cadia East Au-Cu porphyry deposit, New South Wales, Australia, for correlation with metallurgical parameters. P-wave modulus, calculated from density and P-wave velocity, exhibits a correlation with small-scale crushability (A*b) test results, and hence offers a means for æcontinuousÆ characterisation of ore crushability at Cadia East. Magnetic susceptibility has proved to be a good indicator of alteration styles, and is a possible indicator of crushability.

Jan 1, 2009

By A J. Weston

Block or panel caving technology is far removed from that of the top slicing and block caving of the late nineteenth or early twentieth centuries. The rapid mechanisation and expansion of these methods in the late twentieth century was as much a result of the change of the technology of the unit operations of development, ground support, drilling and blasting and transport as it was of the advances in geotechnical understanding and practice. The small footprint gravity and scraper block caving mines with boundary weakening, rail transport and shaft hoisting of the early to mid-twentieth century have been replaced by massive high lift panel caves using preconditioning of the ore, large load-haul-dump units, adjacent crushers and conveyors to surface. The technology changes in the unit operations are described and the drivers for these changes examined.CITATION:Weston, A J, 2016. The evolution of block caving technology, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 265–274 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

IN the underground department of a mine, we may fairly say that "good management is based upon three elementals: first, sound engineering; second, proper coordination and efficiency of every human unit; third, economy in the purchase and consumption: of supplies.This paper is practically an analysis of the second element; which stands out prominently as the most important in the winning of successful results. The human units are divided into officers and men. The officers intermesh. One man takes responsibility where another throws it down; incessantly new conditions are arising where they may be doubtful of their powers; and always, on account of the three shifts, varying methods of work are coming into conflict. This very often results in disorganization. What is most necessary to guard against this is an esprit de corps, which would influence officers to stifle personal feelings for the general welfare of the department, To secure co-operation and loyalty of the staff, the writer recommends for the mines of the field a system of profit-sharing. Distributed on a salary basis, together with liberal holidays (not less than three weeks in each year) on full pay...

Jan 1, 1912

By V Mutton, L Potts, D Joyce

This paper describes the method of extracting sill pillars within the underground operation from under unconsolidated mullock fill at the Cracow Gold Mine. This pillar recovery method was initially successfully used to recover sill pillars at Crusader Mine, Western Australia in 2001. Globally significant resources have been sterilised due to the placement of loose rock fill above crown pillars and within adjacent stopes. The method described here offers significant opportunities to increase recovery of sill pillar recoveries.The royal orebody sill pillars at Cracow Gold Mine form a significant resource. Extraction of these pillars needed to be undertaken with minimal ore dilution and maximum ore recovery. The application that was selected to consolidate the loose mullock fill above each pillar used an injection grouting process (Minova FB200).Cracow Gold Mine mining method is bottom up bench mining. The pillars were left within the orebody to allow for stoping to commence whilst the decline was being developed. Due to the remainder of the orebody being extracted the only access to consolidate the backfill was from the sill pillar extraction level. Numerous problems were encountered and overcome from product selection and trial, system of injection to extraction.This pillar recovery process achieved a 95 per cent recovery of the sill pillar compared with an estimated 60 per cent typical for other mining options.CITATION:Potts, L, Mutton, V and Joyce, D, 2012. Pillar recovery at Cracow gold mine using grouted consolidated mullock, in Proceedings Narrow Vein Mining 2012 , pp 179-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012