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By C A Heinrich, Morse M. P, Cruickshank B. I, Pyke J. G, Whitaker A

Very little public domain information is available on the exploration signature of the Coronation Hill Au+Pd+Pt deposit. From 1987 to 1990 the BMR (now AGSO) carried out geological, geophysical and geochemical (whole-rock, stream, soil and rock chip) surveys within the South Alligator and Kakadu Conservation Zones and defined several key parameters useful for exploration programs. The essential geological ingredients for the style of Coronation Hill Au+Pd+Pt¦U deposit are oxidised, low pH fluids, dilatant fault structures, a thick neutral to oxidised cover sequence and chemical traps in the basement. In geophysical data, the areas surrounding the mineralisation can be detected by airborne magnetics as major lows in magnetite-rich rocks, whereas in airborne gamma-ray spectrometry data, imaged spectrometric channel ratios such as U2/I'h and U2/K highlighted alteration surrounding the deposits. Three types of stream-sediment and soil samples were taken from each site: (1) -1 mm mesh, 5 kg sample for bulk cyanide leach (BCL) analysis for Au, Pd, and Pt; (2) 1 kg sample of -1 mm mesh sediment for fire assay/ICPMS analysis for Au, Pt and Pd; and (3) 50 g - 180¦ mesh sample for a variety of trace element analyses, including Au, Pd and Pt. Techniques 2 and 3 gave similar results for Au, Pt and Pd, while the recovery rates for Pd and Pt from the BCL samples were considerably lower. Other trace elements did not define unique indicators for Pt or Pd mineralisation, as each sample reflected the dominant lithology in the drainage basin. Rock chip surveys were useful in determining which faults were associated with the ore fluid in regions of multiple fracturing. Results from these exploration-style surveys also confirmed that the Coronation Hill deposit is a variant of the unconformity-style of mineralisation, as all significant geochemical and/or geophysical results occur at or below the unconformity.

Jan 1, 1994

By R Williams, P Godwin

In a time of changing rainfall patterns and in the light of recent tailings dam failures, there is closer environmental scrutiny for proposed tailings dam construction or expansion. Therefore the elimination of the traditional tailings dam could provide both environmental and cost benefits to an operation. One method to dewater tails is using pressure filtration to achieve lower moistures than what is currently available using other dewatering technologies. Further benefits include a higher rate of filtrate recovery, reuse of waste material and the potential for dry stacking of the filtered tailings cake, thereby minimising both risk and cost. This paper chronicles the replacement of two existing belt filter presses with a single McLanahan recessed plate filter press to dewater a tailings stream at a Bacchus Marsh site. It covers the slurry testing, equipment selection, installation, commissioning and operation of the filter press to achieve the following objectives:• removing the current tailings dam and slimes cells from the existing process to minimise failure risk and reduce the cost of a dam upgrade, as well as operational and maintenance costs• free up the surface area which was previously occupied by tailings dams and slimes cells• recover additional water to be returned to the process• reduce flocculent usage• reduce truck movements and handling.The project’s owner also expects to reduce carbon emissions by over 3000 t over the lifetime of operation as well as substantially reducing operating expenditure. By recognising the carbon reduction benefits, the project owner was able to successfully achieve partial funding through the Voluntary Waste Industry Protocol.An unanticipated, but as yet unquantifiable, bonus for the project was to seek an offtake agreement for the tailings thereby allowing the tailings to be considered a valuable source of beneficiated clay suitable for the construction industry.CITATION:Godwin, P and Williams, R, 2017. Pressure filtered tailings – environmental and cost benefits, in Proceedings MetPlant 2017, pp 324–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By R Berry

This paper looks at two ways to estimate the bulk mineralogy of the rocks for assay intervals. The aim is to find an efficient indicator of the most common minerals in the rock. Phase (modal) analysis has traditionally been done using visual methods such as point counting and image analysis. A modern version of this process is the X-ray point counting routine using the SEM-EDS based software. These methods are too slow and expensive for routine analysis of bulk sample mineralogy at the normal assay spacing.Two sources of data were considered that provide information that can be used to determine the mineral abundance in assay samples. The most widely applied method is (semi-) quantitative X-ray diffraction (QXRD). The QXRD method is most applicable to major minerals and has limited application to minerals at low abundance. The nominal detection limit is 0.5 per cent. Values below five per cent have large errors. A second, less common, method is calculation of mineralogy from chemical assay data. Conversion of chemical analyses to mineralogical analyses depends on the unique chemical composition of each mineral. Elements only found in one mineral are easily accounted for, but many compositions are ambiguous. Deciding on the actual mineralogy is not simple. Recalculation of mineral mode from chemical analyses is more accurate than QXRD when the correct minerals, and mineral compositions, are known.Where only a few QXRD analyses are available they can be used to setup a protocol for calculation of mineralogy from assay data. Linear programming works well in this environment. The best results are obtained when both H2O and CO2 are directly measured. Loss-on-ignition (LOI) should be included if these are not available.Where both QXRD and chemical analysis are available for all samples, the best results are obtained using the least squared method to merge the data sets assuming QXRD has much higher analytical errors than chemical assays. The combined method provides more robust results because the high abundance minerals are controlled by the QXRD measurements while the chemical assays improve the precision for low abundance minerals

Sep 5, 2011

The Youga gold mine in Burkina Faso, West Africa, is scheduled to produce first gold in the third quarter of calendar 2007. The project is expected to produce 540 000 oz of gold over 6.5 years, from a conventional open pit carbon in leach mine. The direct capital cost of the project is US$47 M. Etruscan Resources Inc, a Canadian based gold exploration and development company, holds 90 per cent of the project company Burkina Mining Company SA (BMC). The state of Burkina Faso is free-carried for the remaining ten per cent of BMC. RMB Resources Limited, of Melbourne Australia, has arranged a US$35 M project finance facility for BMC (the Borrower) as the majority of funding for the Youga project development. The loan facility was provided by RMB Australia Holdings and Macquarie Bank Ltd (the Lenders) each as to 50 per cent in the lending syndicate. The Lenders also provided a gold hedging facility to guarantee a minimum price for the projectÆs gold production. Burkina Faso is a francophone country, part of the Economic and Monetary Union of West Africa (UEMOA). The project financing is the first such facility to be arranged for a mining project in Burkina Faso, with little or no precedent available in other UEMOA countries. Therefore, while the Youga gold project is forecast to be a robust project applying conventional mining and processing methods, a number of legal, technical, commercial and social issues required identification, evaluation and resolution before the loan could be established. This paper describes that evaluation process and the resolution of these issues. In-house experience and expertise in both the LendersÆ and BorrowerÆs teams has facilitated a greater understanding and æownershipÆ of the issues and hence provided comfort with risks which might not normally be taken in conventional project developments and project financings. As a result, blanket external reviews were not required by the Lenders. A long-standing relationship between Etruscan and RMB Resources also facilitated solutions to a number of issues. Nevertheless, a degree of flexibility by the Lenders, the Borrower and Etruscan was required to successfully close the financing.

Jan 1, 2007

THE exceptional rainfall characteristic of the West Coast of Tasmania, in conjunction with the rugged topography of the district, has always suggested the utilization of water-power, and from the earliest days of the Mount Lyell Company theeventual installation of a hydro-electric power scheme, making use of some near-lying lake, has constantly been kept in view. At the period of the inception of the company, however, the time was not ripe for such an undertaking, and it is only oflate that the various important considerations involved have sanctioned incun;ing the heavy expenditure necessary, with the positive assurance of permanently reaping the benefits expected. The West Coast of Tasmania contains many lakes of varioussites; situated at high levels, and, although the catchments of these lakes are not very extensive, still, the excessive rainfall is so constant over long periods that its regularity may be relied on as offsetting the limited catchments. The explanation of the abnormal rainfall is simply the circumstance that the West Coast Range forms the first high land barrier which is met by the moisture-laden westerly and north-westerly winds blowing off the Southern Ocean. By the time the clouds strike the mountains they ride very low, consequently the elevation of the range, the peaks of which do not exceed 3000 to 4000 ft. above the sea, is sufficient to cause a copious precipitation. Lake Margaret, which is situated five miles north of the reduction works, was first recognized as a possible source of waterpower by Mr. Hugh Ohrisp, a surveyor, who visited it about 1893-4. Earlyl in 1895, while the preliminary work on the erection of the first furnaces of the Mount Lyell Co.'s reduction...

Jan 1, 1915

Gold mineralisation at the Kerimenge-Lemenge prospects is a classical example of myltiple, overprinting events, associated with intrusive-related hydrothermal systems. Repeated emplacement of high level dacitic porphyry bodies (Edie Porphyry; 2.4 - 3.8 Ma) was accompanied by a phreatomagmatic eruption which formed a diatreme-maar complex. Later hydrothermal fluids utilised permeable fault zones and diatreme contacts. Mineralisation took place during two main events. Stage I consists of early quartz - illite/sericite - carbonate phase with associated pyrite-arsenopyrite mineralisation. This phase is zoned from quartz - sericite-pyrite/arsenopyrite in the south at depth, to dominantly manganocarbonate - illitic clay - arsenopyrite- pyrite_s significant base metals in the north and at shallow levels. The majority of known gold (18.1 Mt @ 2.0 g/t Au) at Kerimenge is associated with Stage I activity. The gold occurs primary within the lattice of the sulphides and is metallurgically refractory. Fluid inclusion studies indicate early boiling and progressive cooling and dilution of hydrothermal fluids during the evolution of the Stage I event. Near paleosurface condensation of gases, which evolved off the boiling system at depth, produced abundant low pH bicarbonate fluids. During the waning phases of Stage I activity, these bicarbonate condensate fluids descended down permeable structures and formed banded manganocarbonate veins. High grade non-refractory gold mineralisation during Stage II event is restricted to favourable structures at relatively shallow levels and in the northern regions of the prospect area. Gold in this event exhibits a distinctive Au - Ag - Te -Cu geochemical signature, and is associated with hessite - tennantite - chalcopyrite mineralisation within quartz veining. Alteration and fluid inclusion studies indicate that this style of mineralisation is a result of the quenching of pulses of hot, late magmatic mineralised fluids by the cold condensate waters.

Jan 1, 1997

By K Li, C Zhang, i, J Oh, S Saydam, H L. Ram

Rock surface roughness plays an important role in excavation engineering projects and applications related to surface support structures, such as shotcrete and thin-sprayed liner (TSL). The morphology of the substrate affects the mechanical behaviour at the interface significantly. Therefore, it is necessary to quantify the roughness to investigate the relationship between roughness and mechanical properties. The joint roughness coefficient (JRC) proposed by Barton and Choubey (1977) is widely used in practice. It initially estimated the roughness by comparing it to 10 standard profiles visually. However, this method has lots of limitations, it is not only subjective but also a two-dimensional parameter with a small lab scale (Beer, 2002). The subsequent research on JRC, from visual comparison with Barton’s standard profiles to measuring the roughness with a profilometer (Weissbach, 1978; Alameda-Hernández et al, 2014). Then, 2D profiles or 3D surfaces by different technologies with higher resolution and accuracy, such as 3D laser or optical scanners (Fardin, 2004; Jiang, 2020, 2021). These 3D scanners are expensive and only suitable for laboratory scales. LiDAR scanners (Lato, 2009; Aubertin, 2022) have been applied in industrial size, but it is difficult to achieve a millimetre-level accuracy, which is mostly used to detect the thickness of shotcrete in practice. Thus, finding a cost-effective surface roughness measurement method with high accuracy is necessary. Photogrammetry is another method to digitalise the roughness of the surface. Similar to 3D scanners, photogrammetry also generates the point cloud of the objective surface and then reconstructs the 3D model of the objects. 3D reconstruction technology is a trendy technology in recent years. The structure from motion (SfM) algorithm (Westoby, 2012) to rebuild the 3D model with a flexible workflow, aligning photos, building dense point cloud, mesh and texture, which has been proved that can rebuild an accurate model in variable fields.

Nov 29, 2022

The Hemersley Ranges are located in the North West Division of Western Australia and extend, approximately, from latitudes 21¦ 30! to 23¦S and longitudes 117¦ to 120¦E. Their mean height above sea level is'. 2,000 feet, and they rise from 600 to 800 feet. above the gen- eral level of the tableland which extends south-east from the coastal town of Roebourne.. Mt. Bruce, the highest peak, is 4,024 feet above sea level. The ranges are intersected by numerous north-flowing streams, dry during the greater part of the year, which have carved deep gorges, and it is in these that the principal deposits of orocidolite outcrop. The presence -of the mineral was first recorded in 1917., but the deposits remained untouched until 1937 when reports of a strong market demand for-croeido lice resulted in considerable prospecting and mining activity, particularly in Yampire, Wittenoom and Daleis Gorges. . It was established also that the blue asbestos belt extended from Willi- Wolli Springs north-west to Millstream Station, i.e.,-over a.:length of 180 miles and a width of 20 to 30 miles. A number of attempts were made to develop aid treat the Yampire and Wittenoom'Gorge deposits from 1938 onwards, but, for a ,variety of reasons, none of these-proved successful. Current production,. is wholly by Australian Blue Asbestos Pty. Limited at Wittenoom Gorge. This company commenced operations at the Wittenoom Mine in 1946, with an output of 601.8 long tons of- fibre,. and later transferred tb the Colonial Mine about one mile to the north-west. Output has been increased steadily to an' average of 12,000 to 14.,000.. long tons; per annum over the past six years. The total Western Australian output to the end of 1962 is reported by the Mines Department as 110,013 long tons valued at úAl2,403,728..

Jan 1, 1964

By K A Plumb

New structural studies in the Walker Fault Zone of eastern Arnhem Land are integrated with basin-wide reconnaissance observations, made to refine models for the structural evolution of the McArthur Basin and provide new insights into the nature of metal logenetical ly important pre-inversion phases of the basin's evolution. At least five principal events may be identified during the Proterozoic: The Tawallah Group and equivalents were deposited throughout the McArthur Basin during an extensional event. Rifting of an incipient Batten Trough occurred at this time, in a terrain characterised by orthogonal, linked extensional faults. Uplift and erosion of the Tawallah Group accompanied continuing extension and was penecontemporaneous with continuing deposition of the overlying Parsons Range Group, within a precursor to the Walker Trough. Dt (of the Walker Fault Zone) relates to a new rifting event, penecontemporaneous with deposition of the McArthur Group and its equivalents in the Walker and Batten Troughs. This rifting accompanied dextral strike-slip faulting along northerly-trending bounding faults, as a result of northwesterly-directed oblique extension, leading to pull-apart basins. D2 inversion of the Batten and Walker Fault Zones pre-dates deposition of the Roper Group. In the proposed model WNW-ESE directed shortening (D2.), accompanied by folding and thrusting, and by local development of cleavage in the Walker Fault Zone, is seen to be followed by northerly-trending sinistral faulting (D2b), about a SE to ESE-directed compression. D3 is basin-wide and post-dates the Roper Group. It is characterised by conjugate faulting and folding about ENE to NE-directed compression. The latest Proterozoic event to be identified (D4) comprises widespread north-trending strike-slip dextral faulting of Roper Group, coupled with N-S directed thrusting across the Urapunga Fault Zone and Murphy Inlier This is accompanied by late dextral reactivation of NNW to NNE-trending faults in the Walker and Batten Fault Zones.

Jan 1, 1994

Microorganisms have been used throughout history for the benefit of mankind with some of the earliest applications being in the production of fermented foods and beverages. Reactions involving inorganic substances such as metals, sulphur and sulphide compounds were hardly ever used until the early 1900s when it was discovered that Thiobacillus ferrooxidans was capable of promoting the oxidation of metal sulphides in ores. Today, it is widely recognised that biotechnology has great potential in the minerals industries, particularly in such areas as the leaching of low-grade ores of metals such as copper, gold and uranium; removal of heavy metal ions from process streams and from liquid process wastes; and in the desulphurisation of high-sulphur fuels. Although widespread commercialisation of mineral biotechnology has not yet been achieved, it is estimated that by the Year 2000 mineral biotechnology will have a significant impact on the minerals and metal industry and will probably account for tens of billions of dollars worth of annual production world-wide. This paper examines the actual and possible future applications of biotechnology in the minerals, metal refining and fossil-fuel processing industries. Firstly, the important chemical (and biochemical) principles involved in bio-dissolution of metals from ores and solid wastes, and in bio-accumulation of metals from process and waste solutions are reviewed, including leaching practices - past, present and future. Microbial desulphurisation of coal, and microbially-enhanced oil recovery are also discussed. The practical aspects of genetics and genetic engineering, the types and characteristics of those microorganisms important to mineral biotechnology, and the current research trends are reviewed as well. KEYWORDS: Biotechnology, microbial leaching, bioaccumulation, biosorption, bioleaching, biohydrometallurgy.

Jan 1, 1993

By Mudge S. T

Tin mineralisation occurs at Renison Bell, near Zeehan in Tasmania, as a group of cassiterite-bearing massive pyrrhotite bodies in Cambrian sedimentary rocks. Mineralising fluids from the underlying Pine Hill Granite have replaced carbonate rocks with massive sulphides and cassiterite. The discrete blocks of massive pyrrhotite have high density and high magnetic susceptibility contrasts with the comparatively barren country rock. They are strongly remanently magnetised and are excellent geophysical targets. A detailed geophysical model of the mine was created from a database comprising 1:2500 scale geological mapping and geological logs of approximately 4000 drill-cores. The model comprises 93 parallel cross-sections, each 1.5 km long, spaced 20 m apart. Each cross-section is comprised of up to 150 polygons which represent all known individual rock types and orebodies. The magnetic response of the model was computed and the residual between the model and the observed response, measured by a low-level helicopter magnetic survey, revealed several anomalies unaccounted for by the model. Drill testing of these anomalies led to the discovery of several hitherto unknown massive sulphide occurrences. Surface gravity data of the mine and surrounding district were enhanced by applying digital terrain corrections. The corrected Bouguer anomaly revealed a hitherto unknown positive anomaly associated with the ore zones of the Renison mine. The gravity anomaly of the model was also computed. Unfortunately, the limited resolution of the observed data prevented the delineation of ore targets. The terrain-corrected Bouguer gravity data were also used to model the shape of the underlying non-magnetic Pine Hill Granite. A computer inversion method was implemented to build a 3D block model of the granite. Results agreed with previous conventional 3D modelling techniques but yielded improved resolution of the granite form. The project involved development of new computer software to build and edit the large and complex 3D geophysical model of the mine and to compute the model's magnetic and gravity responses. Software was also developed to build and compute the gravity response of a 3D block model of the underlying granite.

Jan 1, 1997

By D A. Shushkov

Analcime-bearing rocks are one of the varieties of raw zeolite material, although the characteristics of analcime are not as good as other kinds of zeolites such as clinoptilolite or mordenite. However, some fields of application of analcime-bearing rock have been found, eg a method of water purification has been developed and patented. Analcime-bearing rocks are rather widespread in the Timan region of the Komi Republic of the Russian Federation. They are represented by Upper Permian siltstones and mudstones. The analcime-bearing rocks have the following mineral composition (per cent): clay minerals (50 - 70 per cent), quartz (ten to 30 per cent), analcime (one to 30 per cent), feldspars (two to ten per cent), carbonates (two to five per cent) and pyroclastic material. Analcime aggregates encrust cavities and infill microfissures in rock. Both microcrystalline (crystals <0.01 mm in size) and medium-crystalline (~0.5 mm) aggregates are observed. The mechanical, gravitational, magnetic, sorption and ion-exchange properties of analcime-bearing rocks have been studied. They are characterised by a high index of grindability and a low index of abradability and crush resistance, low values of the benzol-based pore volume and toluene-based specific surface area, and a medium porosity value. The magnesium based ion-exchange capacity (IEC) ranges from 28.7 to 196 mg+equiv/100 g. Analcime-bearing rocks of the Timan region are characterised by low beneficiation potential. Preliminary ultrasonic treatment of the analcime- bearing rocks is efficient for the destruction of intergrowths along their boundaries and production of free analcime aggregates. The proposed beneficiation procedure yields 95 per cent analcime concentrate. In the Komi Republic, analcime-bearing rocks are utilised in agriculture. They are also used for domestic needs (eg as biotoilets for domestic animals) and the solution of ecological problems (regeneration of soil polluted by oil). We have completed experiments on the purification of potable and industrial water using analcime-bearing rock subjected to thermal treatment. The experiments demonstrated that it was possible to decrease water colouration by 20 per cent, turbidity by 79 per cent, permanganate oxidation by 30 per cent and total iron content by 70 per cent.

Jan 1, 2008

The Inglewood Gold Project consists of several titles in and around the Inglewood and Wedderburn Goldfields which were purchased from Strata Mining Corporation (now Excalibur Mining Corporation). The Inglewood goldfield has a historical production of approximately 160 000 tonnes at 23 grams per tonne. The company has reopened and developed the Maxwells reef, picking up a high-grade shoot (Max Shoot) identified and worked by Goldquest et al up until 1994. Production ceased on a low gold price, rapidly reducing vein size and a requirement for further development. Greater Bendigo Gold Mines Ltd (GBM) has undertaken the development and encountered the mineralised vein in an increasing size setting with high grades and the existing mine development has access to a further shoot to the north (Max North Shoot). The Maxwells reef also contains the Woolf shoot south of the Maxwells shaft and an inferred resource of ~20 000 ounces is contained from 60 m below surface. Best intersection 2.9 m at 50 g/t. The Maxwells reef area produced approximately 20 per cent of the Inglewood goldfields production and GBM is preparing to increase its exploration efforts across the rest of the field. A processing plant has been constructed at the Maxwells mine site, which is capable of treating tailings, hard rock and alluvial material utilising gravity recovery. The existing Maxwells tailings have been excavated and treatment commenced. It is intended to produce a sand product from the tailings for resale and to reduce the storage requirements per tonne. Several large water dams constructed by Goldquest in the 1990s are being re-engineered to enable storage of significant tonnages of tailings. A level of surface and underground production is planned for 2008 and this is to be expanded into 2009 and beyond. The long-term future at Inglewood is envisaged as structural repeats at depth below the current workings and a project plan to gain deep access will be prepared on successful drilling results.

Jan 1, 2008

By Smith CB, Boxer GL

The Argyle diamond deposits in the East Kimberley were found as a result of a long term exploration programme, begun in 1972 by the Kalumburu Joint Venture (KJV), to search for diamonds on the Kimberley craton. When CRA Exploration Pty. Limited joined the KJV in 1976, it was re-named the Ashton Joint Venture (AJV). The Kimberley craton was considered prospective by analogy with structural settings of diamondiferous kimberlites in Africa. Diamonds were found during regional drainage sampling in Smoke Creek in late 1979, which led directly to the discovery of the rich Argyle lamproite diatreme (AK1) and associated alluvial deposits of Smoke and Limestone Creeks. The diatreme intruded into quartzites, sandstones and shales of Adelaidean age, and consists predominantly of lapilli ash tuff, with minor coarse and fine ash tuffs, 'non-sandy tuff' and olivine lamproite dykes. Erosion of the diatreme has produced the alluvial deposits of Smoke Creek and Limestone Creek to the north and east. Argyle diamonds are of predominately industrial quality, and the typical diamond is a brown, irregularly shaped, frosted, heavily resorbed form with abundant graphite inclusions, well developed etch channels and prominent hexagonal surface depressions. The pre-feasibility evaluation of AK1 comprised diamond drilling, surface and underground sampling, metallurgical sampling, marketing studies and ore reserve estimation. The proven AK1 ore reserve is 61Mtonne at 6.8ct/tonne. Evaluation of the alluvial deposits gave results of Upper Smoke Creek, 580 000 tonne at 4.6ct/tonne and Limestone Creek, 1.7Mtonne at 3.5ct/tonne. Commercial production from the two alluvial deposits began in 1983 with production for the year reaching 6.2 Mct. Mining of the alluvial deposits at three to five Mct/year is proposed to continue until the start of mining of the AK1 deposit in late 1985 or early 1986 at which time a new processing plant and associated infra- structure will have been constructed adjacent to the AKl deposit in the Limestone Creek area. Production is planned at three Mtonne/year, producing 25Mct/year, which will make Western Australia the largest producer of natural diamond (by weight) in the world.

Jan 1, 1984

By B Banerjee, H Masoumi, X Shen, S Raval, D Tannant

Structural mapping of pit walls can be performed using digital images and photogrammetry software, but the performance is limited by weather and environmental conditions including dust, rain and light. On the other hand, active sensors such as terrestrial laser scanners (TLS) and total stations (TS) suffer from vertical orientation bias and occlusions when persistent discontinuities dip at the same angle as the scanner line-ofsight. The recent development of the compact light detection and ranging (LiDAR) systems has made it possible to mount these sensors on unmanned aerial vehicles (UAVs) or drones which offer the potential to overcome limitations that are inherent in existing mapping systems. This study details the research involving integration and application of an advanced UAV-LiDAR system for structural mapping of a highwall. A state-of-the art laser scanner with an inertial measurement unit (IMU) and real-time kinematic global positioning system (GPS) was integrated on to a UAV. The system was first tested in a laboratory condition. Then the UAV-LiDAR system was employed to map a highwall of a coal mine. The planned flight trajectories tested the system at variable distances from the highwall face and at various speeds. The raw data collected from individual sensors were fused, filtered to remove noise, and segmented to produce a surface scan model. Finally, the point density and surface coverage were measured using the surface scan model of the highwall. The parameters were compared with equivalent measurements computed from a reference TLS data. The study demonstrates the capabilities of a UAV-LiDAR system to generate accurate and occlusion free data for mapping highwall geological structure with very quick and efficient flights in the field. CITATION:Raval, S, Banerjee, B, Shen, X, Masoumi, H and Tannant, D, 2018. Evaluation of a UAV-LiDAR system for mapping geological structures in an open pit highwall, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 496–503 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By P D. Munro

The spatial distribution of ore with similar processing properties or domains within an orebody may be identified early in the assessment of an orebody to provide a sound basis for later development of the orebody. The assignment of domains in the primary sulfide portion of an orebody is often more difficult than recognition of the oxidised, supergene and related domains usually located towards the top of the mineralised volume. This paper will discuss some approaches to assigning domains within the primary sulfide portion of an orebody. The processing properties of each mining block will be known if the contained domain(s) and their proportions are known. The use of both physical and chemical ore properties to assign the domains is discussed. The domains based on similar processing properties do not necessarily coincide with geological zones assigned by geoscientists. As part of assessing the physical properties of ore, the modal analysis of the ore with respect to the valuable sulfide minerals and the sulfide and non sulfide gangue minerals has to be known, along with the traditionally used elemental assays for valuable and penalty elements. Two scales for determining other physical ore properties will be considered: the mesoscopic scale (examined by human eye) and the microscopic scale (examined via a microscope under high magnification). The strengths and weaknesses of the data obtained at the two scales are discussed in the paper. Broadly, data collected at the mesoscopic scale are much less expensive but the types of data available are more limited. Methods for evaluation of chemical ore properties are also discussed. After establishing a basis for establishing the spatial distribution of domains, variability testing is required to verify the integrity of the designated domains. In contrast, each block of ore in some orebodies has been assessed principally via the results of a laboratory separation on a number of drill core samples or composites from throughout the block, with minimal or no attention to the concept of domains.

Jan 1, 2008

By Allnutt S. L, Carswell J. T, Mutton A. J

The Dugald River Zn-Pb-Ag deposit occurs within the complexly deformed and metamorphosed sediments of the Middle Proterozoic Cloncurry Terrane, Eastern Succession, Mount Isa Inlier. The sedimentary sequence comprises a thick package of variably carbonatic argillitic and siliciclastic sediments of the Corella Formation, Lady Clayre Dolomite and Knapdale Quartzite. A slate and calc-argillite unit locally referred to as the Dugald River Slates is the host to the economically significant deposit. The deformational history of the Dugald River area involved three phases of ductile deformation. The present geometry of the Dugald River Main Lode is recognised as a strike extensive steep westerly dipping tabular sheet, within which a steep north westerly plunging zone of pronounced thickening is evident. This zone is interpreted to have formed during folding via remobilisation of the sulphides into a shoot-like body, the geometry of which was controlled by stretching associated with the folding. Further modification of the shoot and sulphide re-distribution has resulted from late phase transgressive shears. The sulphide mineralisation is characterised by three distinctive sulphide types, laminated, banded and breccia, the distribution of which define two broad zones. The northern zone is a narrow I - 5 m thick stratabound unit comprising finely laminated and banded sulphide mineralisation within a well bedded fine grained argillite sequence. This is part of the Lady Clayre Dolomite sequence and is a predeformational precursor form of mineralisation. The southern zone comprises the thickest development of mineralisation (up to 30 m) characterised by slate-sulphide breccias and veins derived from complex polyphase remobilisation of the sulphide mineralisation. It is this zone which forms a stratabound locally transgressive body within the high strain Dugald River Slates and which contains the main body of economic mineralisation. Sulphide mineralogy comprises sphalerite, pyrite, pyrrhotite, galena and traces of chalcopyrite, pyrargyrite, tetrahedrite, marcasite and arsenopyrite. The present resource for the Dugald River deposit stands at 38 Mt grading 13.0 per cent Zn, 2.1 per cent Pb and 42 g/t AS. The Dugald River Zn-Pb-Ag deposit is regarded as an example of a syndiagenetic stratabound sulphide accumulation which, as the result of polyphase deformation and upper greenschist to middle amphibolite facies metamorphism, has undergone extensive remobilisation and Rccrystallisation.

Jan 1, 1993

By P M. Downes

Porphyry-related skarns are common around thePacific Rim. Examples include Cadia and Goonumbla (Australia) Ok Tedi (PNG) and Ertsberg and Grasberg (Indonesia). Although usually treated as separate to the adjacent porphyry copper-gold (Cu-Au) deposit, skarns near porphyry deposits are commonly inextricably part of the larger Cu-Au system(s). Using Cadia as the primary example, we demonstrate that large, zoned, calc-silicate skarns necessitate very large porphyry systems. The Big Cadia and Little Cadia Fe-Cu-Au skarns are associated with the Late Ordovician to Early Silurian high-K calc-alkaline to shoshonitic Cadia Intrusive Complex (CIC). Together, these skarns total ~40 Mt of Cu-Au ore but are much smaller than the adjacent Cadia EastûFar East, Cadia Hill, and Ridgeway porphyry-related Cu-Au deposits. Historically these skarns were large, economically significant and highly controversial deposits. Porphyry-related skarns typically have well-developed calc-silicate and ore zonation. At Cadia, classic skarn zonation has been mapped between Cadia Quarry (proximal) and Big Cadia (distal). Over this 800 minterval, mineralogy trends from: proximal garnet > pyroxene, grading to; fe-oxide-rich skarn; and distal haematite-epidote-rich skarn. At Little Cadia, analogous but symmetrical alteration zonation is present. Big Cadia formed from fluids that migrated laterally within calcareous units and were sourced from strongly altered quartz monzonite phases of the CIC at Cadia Quarry. Isotope studies and mass-balance calculations suggest that prograde and retrograde skarn alteration was caused by magmatic dominated fluids. They also indicate that the mapped alteration system at Cadia Quarry is insufficient to account for the total volume of Fe present at Big Cadia. Despite the typically oxidised nature of many porphyry systems, not all skarns in the porphyry environment are oxidised. Assimilation of carbonaceous sediment by hydrous, alkaline intrusions could lead to reduced Au skarns rather than porphyry deposits. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Solid Energy New Zealand (SENZ) uses a 20+ year period for integrated planning of all its business activities. It has an ongoing program of coal resource assessment to optimise future mines within this 20 year period, using a six step resource and mine planning process. Desktop review and conceptual study at preliminary Levels 1 and 2 are based on general coal resource information. Further coal resource investigations are carried out for the more detailed evaluations in secondary assessment, prefeasibility study, feasibility study and detailed engineering from Levels 3 to 6. At Levels 1 and 2, completing conceptual planning, including preliminary resource evaluation and economic appraisal to the target cost uncertainty level of ¦33 per cent, is challenging in New ZealandÆs highly variable geological and geographical conditions. Where coal deposit geometries are relatively simple, approximate methods for determining pit limits using overburden strip ratios, seam thickness, physical boundaries, and quality cut-offs may be sufficient. Many New Zealand coalfields are however complicated structurally, with multiple seams and extensive folding and faulting. Coal seams are characterised by variable dip, thickness, and quality over relatively short distances. In the North IslandÆs Waikato coalfields, coal is typically overlain by weak sediments and clay rich strata that necessitate very flat cut and fill slope angles. The proximity of these deposits to major infrastructure (including towns, highways and rail lines), significant environmental features such as the Waikato river and lakes, and valuable dairy farmland, add further complexity. Traditional preliminary mine planning techniques applied in these conditions are insufficient. Pit optimisation software, widely used in the metalliferous mining industry since the 1980s, offers the ability to analyse many more specific factors affecting pit limits, mine layouts, and economics, with more rigour and for a much larger number of scenarios, than traditional methods allow. SENZ therefore decided to adapt and use æWhittleÆ pit optimisation software for Level 2 analysis of several Waikato opencast prospects. This paper describes this work.

Jan 1, 2005

By Dawes S

Efficient roof control in colliery operation is a factor that must be maintained for· the maximum reQovery and economic extraction of the mineral. It must be carefully considered in each of the following stages in the life of a mine.1. The primary development and the first working of the mine.2. The maintenance of access roads, intake and return airways.3. The extraction of pillars.FACTORS IN ROOF CONTROLThe main objects of roof control are: The support of the roof in working places, the relief of roof pressure from the workings during pillar extraction, and in some instances the prevention of subsidence of the surface.The support of the roof during development operations and first working, and the subsequent maintenance of these is influenced by:-1. The depth of the seam below the surface.2. The thickness of the seam.3. The dip of the seam.4. The condition of the roof and floor.5. The method of extraction-mechanical or by hand.6. The method of. working-Iongwall or bord and pillar.7. The availability of material.As a general rule, the pressure exerted by the superincumbent strata may be taken as one pound per square inch for each foot of cover, and the crushing strength of coal as 1,500 to 2,000 lb. per square inch; this, of course, varies, but from these figures it may be assumed that seams below 2,000ft. in depth are liable to crush. If any part of the seam is removed, added weight is thrown onto the remaining coal. It is therefpre essential that for effective working this extra weight must be removed or supported as soon as possible.The outstanding principle in the support of mining excavations is to ensure that the supports are set as soon as possible after the natural support has been removed.Where a system of bord and pillar is applied, the early setting of supports reduces the extent to which the roof bends, thereby reducing the liability to ·tension fractures at the centre of the road.

Jan 1, 1947