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Variations in delay timing can have a marked influence on blasting effectiveness and, hence, on total production costs. In single-row bench blasts, delay firing is invariably more effective than simultaneous initiation. In single-row delayed blasts, there is an optimum inter-hole delay above and below which inferior blasting results are obtained. This optimum delay is equal to the time required for each charge to just effectively detach its quota of the burden. The inter-hole delay should seldom be less than 4 ms.m-l of burden.In multi-row blasts in which holes in a given effective row are fired on the same delay, the entire burden on any effective row should be detached from the rock mass just before charges in the next effeotive row detonate. Delays shorter than this give inferior blasting results and an increased likelihood of environmental and slope stability problems. If the inter-row delay is too long, cut-offs can occur, especially where the delay unit is located outside the blasthole. For a surface delay system, the optimum inter-row delay usually varies between 4 ms.m-l and 8 ms.m-l of effective burden. The number of rows that can be fired effectively with surface delay systems (in a single blast) is limited by the threat of cut-offs. Greater interrow delays and a larger number of rows per blast can be fired to advantage with down-the-hole delay systems.There are practical limits to the timing accuracy of all available delay systems. The existence of delay time variability should be recognized and duly considered in the design of blasts.The relationship between delay timing and blasting vibrations is not discussed.

Jan 1, 1977

Fleet management systems have been adopted by many open pit mines throughout the world and the resulting improvement in truck cycle times has been one of the most significant contributors to mine efficiency. Ongoing enhancements to fleet management systems such as interfaces for vital signs monitoring have given incremental efficiency gains. Each incremental improvement is another step towards a grand vision of a totally automated mine. A relatively new fleet management system is being integrated with two other technologies to provide a highly reliable platform for a networked information system which monitors mine machinery and production. The paper reviews the integration project, the features of the new mine site information network platform and the contribution to productivity and safety. The new fleet management system has a predictive truck dispatch algorithm. It also has a distributed database that replicates rapidly so that each machine in the fleet has an identical database, thereby making each machine aware of other machinesÆ locations on the site. High precision systems for navigating and monitoring machinery such as drills, dozers, draglines and shovels provide individual machine operators with cockpit style real-time information to increase their operational efficiency. The integration of the new fleet management systems capabilities with the high precision systems that provide production information, machine vital signs data and operator information means that the mine operations and maintenance managers have real-time access to the whole mine siteÆs production data. Such a mine monitoring and reporting system is dependent on reliable wireless communications and reliable positions. Positions in fleet management and high precision systems for open pit mines are usually provided by global positioning system (GPS). Other global navigation satellite systems (GNSS) such as Glonass, and in the future Galileo, will provide additional satellite cover; however, some parts of open pit mines do not have enough sky visibility for reliable GNSS positioning and so a new centimetre level wireless positioning system called Locata is being integrated with the fleet and high precision systems to augment and backup the GNSS positions. The final integrated system will provide the highest levels of reliable position-based information to all stakeholders in a mineÆs operation, ensuring gains in productivity and safety.

Jan 1, 2008

Diamond drilling was first carried out at Norseman in the Princess Royal Mine, early in this century. Little concentl'ated drilling was done from then until Western Mining Corporation commenced drilling in 1934. Since then Central Norseman Gold Corporation N.L. has continually employed diamond drilling in exploration of the field. After 1946 the advantage was seen of applying broad pattern surface drilling at Norseman in the reef exploration. In 1953, as a result of the steeply rising cost of drilling and the time taken to penetrate surface material by light equipment, heavier drills and new rigs were introduced. The surface drilling programmes called for a greater monthly or annual footage and to satisfy this new techniques were introduced. The Mitchell-21 machines were discarded and A-3000 machines were installed, firstly under a 48 ft. fixed tower, then mounted on a truck with a 20 ft. tower, and finally on a truck carrying a 40 ft. tower. With the mobile units a compressed air compressor is attached. By use of compressed air with either the Reed roller or Hawthorne bit, rate of penetration of overburden is greatly increased. The mobility of the truck mounted machines has greatly reduced the time required to move from one hole to another, and the use of heavier machines on a three shift per day basis has considerably increased the footage per shift. The general result is an increase to 1,500 ft. of drilling per month per machine, while costs have been greatly reduced in spite of increased wages and diamond prices.The underground drilling technique is described. Analysis of performance has not been made because the drillers performance is subject to shaft routine and service.INTRODUCTIONGold was first discovered at Dundas in 1894, and at Norseman, 14 miles north, in 1895. From that tirpe until 1935 mining activity fluctuated. Following the mining revival in 1935, production in the field has remained comparatively stable. This stability in part has been due to the broader scale of operations of Central Norseman Gold Corporation N.L., and in these operations diamond drilling has played an increasingly important role.

Jan 1, 1956

By Case JE

Complete Bouguer and isostatic anomaly maps compiled for Costa Rica provide new insights into the crustal structure and mineralization. Terrain corrections were approximated from the station to a radial distance of 167 km by computer using a 3- minute digital elevation model of Costa Rica and surrounding areas. Isostatic corrections, based on Airy-Heiskanen compensation, were also calculated from 0 to 167 km using the 3- minute elevation model and from 167 km to 180 degrees using combined topographic and isostatic reduction maps. Costa Rica can be divided into four main terranes based on gravity data: a Pacific coastal region, a Pacific inland area, a central region, and a Caribbean coastal region. Negative gravity anomalies along the Pacific coastal margin correlate with an offshore sedimentary basin, and large positive anomalies correlate with mafic and ultramafic igneous rocks on the Santa Elena, Nicoya, and Osa Peninsulas, and at Puerto Quepos. Pacific inland anomalies are separated from the Pacific coastal region by a steep gravity gradient, and over the Coast Ranges a major gravity low overlies a thick section of low- density sedimentary rocks. In the central region, a major gravity low occurs over a thick low-density Quaternary volcanic complex in the Cordillera Central, north of San Jose. A prominent feature of the Caribbean coastal region is an interrupted gravity low over the Limon Basin that reflects a thickening of low-density sedimentary rocks. A conspicuous gravity lineament, trending northeast separates northern and southern Costa Rica. The lineament is defined by the termination of several major gravity anomalies including those over the Coast Ranges, Cordillera Central, Puerto Quepos, and Limon Basin. In addition, the lineament correlates with other geological and geophysical data including: northeast-trending faults, the southern limit of large Quaternary volcanoes, the segmentation of the middle America volcanic belt, and a seismicity gap. This lineament may be the expression of a previously unrecognized major northeast- trending fracture zone in central Costa Rica. An important economic implication of the gravity lineament is a correlation with the termination of gold and porphyry copper deposits in Costa Rica.

Jan 1, 1987

The extent of regional stratigraphic and structural geological mapping so far carried out in Australia is likely to be greatly overestimated by uncritical inspection of the latest authoritative geological map of the continent-that so ably compiled by the late Sir'T. W. Edgeworth David. Vast areas geologically coloured on this map are in fact known only from the most meagre field data, some of Which even include observations of distant views from which the so-called "geology" has been indicated in' reconnaissance reports.This applies to large areas in Cape York Peninsula; the plateau of Arnhem Land, and its margins except on the west where the Pine Creek mineral belt is better known; to the Desert Basin of Western Australia, practically the whole of the western half of the Northern Territory, much of east-central Western Australia, and northwestern New South Wales. Other vast areas are, more happily perhaps, left blank. It is true that prospecting parties have, at various times and with varying degrees of thoroughness, traversedparts of these little-known regions, often, however, in the search for gold or the.more obvious types of metalliferous mineral deposits and, furthermore, too often without leaving any written account of their examination, or with very sketchy details supplied. Unpublished geological surveys also cover some parts of these regions, but, on the whole, the picture we can draw of the regional deployment of rock masses in Australia is far less full than even David's map, with its obvious blanks, presents to us.Lest the practical mineral seeker among us should be inclined to place too much reliance on the prospecting to which I have referred.as giving him a straight hint of what country to keep out of, we may point to the recent discovery of a major sedimentary basin in the east KimberllilYs on which Dr. Teichert will have more to say. And that there are new metalliferous mineral deposits to be foundin parts of these little-known areas no one can doubt, for, after all, new discoveries are made from time to time in areas so well-known as the Victorian gold-fields. I take it then that regional geological mapping is a necessary concomitant of the further development of Australia's mineral resources-but I am not of the school that places it first on the list of priorities, and furthermore I believe that there can be a royal road to regional mapping-an inspired approach based on knowledge already gained and led to fruition by field surveys in key areas, by which there may be obtained a result giving a significantly close approach to actuality with only a fraction of the work that would be required for detailed field surveys on a systematic basis. I believe that a policy of rapid reconnaissance of such a type should be adhered to, especially in view of present deficiencies in numbers of geologists available for all purposes in Australia. The details that must eventually be sought can, I believe, be filled in later as the whole country becomes more developed and amenable to detailed surveys.

Jan 1, 1950

By Y Gu

The Mineral Liberation Analyser (MLA) employs the technologies of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The use of backscattered electron images to define phase boundaries produces very high resolution image analysis and subsequently detailed and accurate particle images and data output. The mineralogy, elemental deportment, grain size, liberation characteristics and mineral associations of a large number of samples can be described. The MLA uses a comprehensive set of analysis methods to meet a wide range of applications. The data from ore characteristion projects completed during feasibility studies are important aids for effective plant design. The MLA can be used to establish variation in the mineralogy of an orebody, identify and quantify the deportment of deleterious elements, and provide valuable information to support comminution and flotation test work. In established plants the MLA data is an important component of plant survey work and monthly composite samples. Changes in feed characteristics and/or operating conditions can be monitored and solutions to any deterioration in recovery and grade performance found. The MLA has extensive applications in the minerals industry. Rare and precious metal samples can be accurately measured using high-resolution grey-scale images. Several new measurement techniques have been developed to perform rapid searches of a large number of samples to provide efficient and accurate analyses of fine-grain, low concentrate material. Quantifying the mineral variability in mineral sands operations is essential to maximising grades and recovery. The MLA produces particle-based data on density, mineralogy, size and shape and has developed measurement techniques to provide the elemental quantification required for the characterisation of these deposits. Nickel sulfide ores can be analysed to provide modal mineralogy, elemental deportment and liberation and locking data. The low-grade and variable nickel mineralogy of these deposits makes the use of quantitative mineralogy an essential component of maximising returns. Coarse particle measurements preserve the in situ textures of ores and support flotation and breakage test work for feasibility studies. The deportment of penalty and bonus elements can be quantified and the association and grain-size data can be used to identify potential separation issues.

Jan 1, 2006

By A Scott, I Onederra

A great deal of technical and research effort has been applied to the development of models to predict fragmentation from rock blasting. A number of quite useful empirical or engineering models are currently available to blasting engineers and consultants, while more sophisticated approaches using mechanistic and numerical descriptions of rock breakage continue to be developed and applied by researchers and explosives companies.The fragmentation resulting from any blast will be heavily dependent on the properties of the rock mass being blasted; however, most empirical models rely on ‘rock factors’ generated from simple rock mass properties to describe the influence of the rock on the blasting outcome. In contrast, mechanistic models need explicit rock mass properties that require sophisticated laboratory measurements and detailed structural data if realistic outcomes are to be generated. The fragmentation modeller is caught between excessively simple rock mass descriptions for the empirical models and excessively complex data requirements for the mechanistic models.This paper briefly reviews the basis of a range of fragmentation models and the rock mass properties on which they rely. Shortcomings in the way that the mining industry tends to characterise the blasting properties of rock are discussed and some practical approaches are described to quantify these properties in both operating and greenfield mining environments. Case studies are presented where specific additional breakage properties and modelling features have been needed to generate a useful description of the fragmentation achieved.CITATION:Scott, A and Onederra, I, 2015. Characterising rock mass properties for fragmentation modelling, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 149–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By S Robertson, I Buitrago

Mine life cycle planning and enduring value are taking centre stage to meet corporate goals and deliver socio-economic outcomes for communities over the life of a mine. There is a general agreement in the literature about mining-induced effects on locals adjacent to mining operations and subsequent closure. In response, international regulatory bodies, through the implementation of global agendas, encourage exploration and mining companies to embrace the concept of corporate social responsibility. This concept is designed to provide sustainable outcomes and maintain a social license to operate over the life of a mine. This paper proposes a practical application of the sustainable livelihood approach as a tool for international planning. With this approach as the governing framework, this paper proposes an innovative tool for mine life cycle planning. Based on the findings, this paper discusses the socio-economic impacts of mining and mine closure. It also argues that transferring some of the benefits from mining to create lasting value for communities needs to be considered at the initial stages of planning for the mine and the community. Findings also indicate that conditions such as a strong local government, good governance arrangements, relevant capacity-building for sustainable livelihoods and a diversified economy are important to transferring some of the benefits from mining to create lasting value for communities. The paper is based on a mixed research technique for data analysis and a case study methodology. The case studies were conducted in Australia and Colombia.CITATION:Buitrago, I and Robertson, S, ?2014. Mine life cycle planning – creating lasting value for communities, in Proceedings Life-of-Mine 2014 , pp 301–312 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By D W. Airey

Frictional rock bolts are widely used because of their low cost. However, they have a thin wall section that makes them prone to corrosion, and they cannot be relied on to provide long-term ground support. It is difficult to assess the capacity after the bolts have been installed as they can only be pulled out if this has been allowed for during insertion. The questions of how long can the rock bolts function effectively and the effectiveness of various surface coatings, which can have significant cost implications are, investigated in this study.A series of accelerated corrosion tests have been performed on frictional rock bolts. The rock bolts, typically 900 mm long, have been inserted into concrete cylinders produced using a styrofoam insert to create the hole for the bolt insertion. Strata rock bolts with four surface coatings have been tested: uncoated black steel, galvanised, enduro (plastic coated) and coated with a proprietary aluminium/zinc alloy. Tests have been performed on two diameters of bolts. Following insertion of the bolts, the concrete cylinders were placed in a large drum filled with saltwater and current was applied to accelerate the corrosion process. The rock bolts were then extracted at various times after the commencement of corrosion. Comparison of the insertion and extraction resistances shows that corrosion initially increases the bolt resistance and that substantial section loss is required for the bolt resistance to drop significantly.CITATION:Airey, D W, 2014. Laboratory corrosion tests of frictional rock bolts, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

It is well documented that drill and blast outcomes affect the downstream mining processes of loading, hauling, crushing and grinding but it can also significantly impact on mine profitability via dilution, recovery percentage, lump generation (iron ore), fines generation (coal, iron ore), coal loss and final wall stability. Drill and blast must therefore be optimised to improve the overall profitability via positively impacting on productivity and saleable product generation. It is however, difficult to achieve this because of the complexity of the number of parameters that must be integrated and managed across the entire mine value chain, ie the concept of æMine to MillÆ. This paper highlights, via a simple case study, the need to have a mineÆs drill and blast system both in control (so that it is predictable to a high degree) and with minimal variability (so the design actually makes it into the field). This type of management control is essential prior to optimisation work being undertaken. The æTeam ApproachÆ is discussed to illustrate the methodology of achieving drill and blast optimisation. A case study is presented to illustrate the potential benefits of this approach which in this mine represented a 27 per cent reduction in powder factor with the downstream functions achieving higher productivity with the same or reduced maintenance costs. It is essential for Australian mineÆs to implement the appropriate management strategies and experienced personnel placement to ensure that their mineÆs drill and blast system is correctly managed to facilitate the optimisation of profit. Without this, the Australian mining sector will become increasingly uncompetitive.

Jan 1, 1999

By M Hedley

Tracking plant and personnel in underground environments provides multiple potential benefits for a mine including increasing safety, better monitoring of production, traffic control, and in the future monitoring and control of autonomous vehicles. The main techniques for wireless tracking are to use radio frequency identification (RFID), signal strength based techniques, and time of arrival (TOA) based techniques. RFID does not provide continuous tracking and signal strength techniques have poor accuracy in the complex radio propagation environment present in mines. TOA based techniques are potentially the most accurate, but most current equipment does not realise the potential of the technique. CSIRO has been developing the wireless ad-hoc system for positioning (WASP) system for wireless tracking in a range of challenging environments including underground mines. WASP has been licensed for sporting applications and has delivered encouraging results in early trials for a surface and an underground mining application. The system utilises a number of ‘anchor nodes’ that are placed at surveyed fixed locations within the mine, and tags attached to plant or personnel to be tracked. The system provides an ad hoc data communication network, thus wired data connections are not required to the anchor nodes. WASP uses transmissions in the 5.8 GHz ISM (instrumentation, scientific and medical) frequency spectrum to perform highly accurate ranging between nodes, hence tracking of tags. The localisation performance of the system depends upon the radio propagation environment, ranging from 0.1 m in low multipath conditions. In this paper we describe the WASP system and provide results of initial testing in an underground mine that shows that the system achieves high ranging accuracy, hence localisation accuracy.

Mar 21, 2011

By D Atheis, S Williams, A Dance, D Taplin

"Resurrected from its former life at the Big Bell operation, the grinding circuit at Evolution Mining’s Edna May operation in Western Australia has many a story to tell. The task of optimising a plant designed for another orebody provides as many challenges as opportunities. Initially faced with a blend of primary and oxide ore, the circuit achieved in excess of 320 t/h until the oxide was depleted, leaving only the much harder primary feed.The 2.0 MW semi-autogenous grinding (SAG) mill and 3.7 MW ball mill were assisted by a 150 kW pebble crusher, but the power limitation of the SAG mill resulted in a drop in throughput. Edna May personnel have been involved in a number of progressive improvements to restore the design capacity of the concentrator and work towards 3 Mt/a or even higher ahead of the gravity and leach recovery circuits.These improvements include: a crush forward configuration of the SAG mill scats partial to full secondary crushing variable speed drive upgrade of the SAG mill lifter and grate design changes ball mill circuit grinding efficiency.This paper summarises the chronology of events that has resulted in significant improvements in throughput by conventional (and in some cases, novel) methods of reconfiguring the existing grinding mills. Lessons learned and hindsight perspectives will be summarised, sharing this educational experience with other operations in a similar situation.CITATION:Dance, A, Atheis, D, Williams, S and Taplin, D, 2014. Grinding circuit improvements at Evolution Mining’s Edna May operation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 63–70 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

By Campbell Brown GA

IN 1904-5 diamond drilling operations in the Mount Morgan mine proved the presence of some inillioils of tons of rich, copper-gold ore, averaging about 45% to 50% silica and 22%Fe as sulphide. To smelt this ore in blast furnaces, without previous concentration, large quantities of basic flux.were required. Unlimited quantities of cheap, limestone, were available at Marmor, on the GladstoneRockhampton railway, 50 miles from Mount Morgan, but the supply of iron flux was a more difficult problem. Smelting operations started, with one' furnace in January, 1906, using as flux low-grade sulphide ore fro:m. the mine, containing very little silica. When the second, furnace was blown in this was supplemented by ironstone from, small aeposits in the immediate district. It was recognized that these sources of supply would be insufficient to keep the full plant going after the third furnace had been blown in. Accordingly, the deposits at Eabra and Mount Etna were opened, neither of which proved capable of supplying the quantity required viz, 1000 tons per week. Negotiations were meanwhile being conducted with the Marble Island Iron and Limestone Co. to obtain the right to mine at Iron Island, where a sufficiently large deposit was known to exist. Shipments from this source commenced in January, 1907, and ceased at the end of July of this year, when the metallic flux from...

Jan 1, 1912

By L I. Rozman

"There have always been development projects that fall short of expectations. In the last decade, we have seen more than the usual number of mining and oil/gas development projects taking significantly longer to develop and costing materially more than expected. The recent resource-equity market slump proves that investors are now far more cautious about investing new capital in the mineral and petroleum resources sector.What have we learned since 2005? Why have projects missed their targets? Why do investors often feel misled?Valuation of a project and the estimation of value is a more complex process than the evaluation of the merits of project development. The merit of project development can be clear from a prefeasibility evaluation, but this is no reason to skip the rigour of a feasibility study. The valuation of any project that is developed with any added risk should be discounted for this added risk.The development of a project impacts on other stakeholders, and the indirect cost of these impacts can have material implications for the cost structure, time and ultimate valuation of the project for its financial backers. The development of new projects (and thereby supply) can also have an impact on commodity prices, and therefore an impact on returns for financial backers.This paper will provide commentary on the author’s experiences and observations as a project developer and operator for 25 years, before becoming a project financier a decade ago.CITATION:Rozman, L I, 2016. Project evaluation and valuation – an investor’s golden rule, in Proceedings Project Evaluation 2016, pp 31–36 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By A K. B Chigwada

Mining organisations grapple with the same problems year after year, wasting incredible amounts of time and money. According to estimates from the International Labour Organization (ILO), over one million work-related deaths occur annually, and hundreds of millions of workers suffer from workplace accidents and occupational exposure to hazardous substances worldwide. Many accident reports cite human failure as a primary cause (Busse and Johnson, 1998). The workers at the Bhopal chemical plant pumped methyl isocyanate into a leaking tank (Morehouse and Subramaniam, 1986). On 3 December 1984, more than 40 tons of methyl isocyanate gas leaked from a pesticide plant in Bhopal, India, immediately killing at least 3800 people and causing significant morbidity and premature death for many thousands more. The company involved in what became the worst industrial accident in history immediately tried to dissociate itself from legal responsibility (Broughton, 2005). Australia is not spared from safety problems either (Lucas, 2022). The ILO Convention 176 (1995) as a response provides that national law should inter alia provide for the supervision of safety and health in mines; the inspection of mines by designated inspectors of the competent authority; the procedures for reporting and investigating of fatal and serious accidents; the compilation and publication of statistics on accidents, occupational diseases and dangerous occurrences; the competent authority to suspend or restrict mining activities on safety and health grounds until conditions giving rise to the suspension are addressed; and worker consultation on matters related to safety and health in mines. This has assisted in getting enough data to define the magnitude of the problem to the mining sector.

Apr 16, 2024

By T Wang, D Wang

Photogrammetry-based techniques supported by traditional mapping tools are more frequently used for open pit geotechnical mapping. It fundamentally involves the collection of geological, structural and rock mass data from pit batters when safe to do so. These are essential components for refining and implementing continuous improvements to geotechnical models. The geotechnical model is used to review bench performance, optimise geotechnical design parameters, interpretation and analysis of pit slope stability. This paper is a case study of implementing different pit mapping methods at Mount Carlton gold mine, North Queensland. It critically reviews the tools required, including the Brunton compass, mobile application Clino, geotechnical data mapping software CloudCompare (2015) and Sirovision software. The review compares the image precision, structural measurements and data analysis. The review also underlines mine site management philosophy for safe geotechnical data collection to identify in-pit geotechnical hazards and the mitigation of potential slope instability. Sirovision is a remote sensing system for site geology mapping and interpreting geotechnical characteristics of exposed mining faces. The system utilises off-the-shelf digital SLR cameras to capture stereo photographs of the rock face and uses the latest image processing technology to generate accurate 3D models. These 3D models are digitally analysed using computational geometry to extract unbiased and accurate geological and geotechnical data. CloudCompare processes high accuracy 3D dense cloud rock surfaces reconstructed with photogrammetry software to extract the geological planes using the FACET or Compass plugins. The major discontinuity sets can be observed and the orientation (dip/dip direction) obtained from the algorithm is accurate and reliable for geotechnical assessment, including kinematic and rock slope stability analysis.

Nov 29, 2022

By T A. J Hopper, S Mukkisa, K-O Ott, D Palmer

RIG Technologies has developed new technology that can successfully acquire high quality natural gamma ray (GR) and hole deviations, downhole while drilling, on reverse circulation drills. This technology survives the hostile downhole environment with shocks of between 400–2500 g for 7– 10 days at a time. The Logging While Drilling (LWD) service eliminates the need to run in-rod surveys, either by the driller or by wireline trucks and crews. This time saving is in the middle of the drilling process, thus enabling drills to keep drilling and increase their productivity. Additional to the natural GR and directional survey, the downhole tool is equipped with sensors to measure the downhole dynamic response of the drilling system providing insights into rock hardness, density and potentially clay types. These parameters have never been acquired behind the hammer before and coupled with surface measurements from the drills themselves, form a rich data set for trainable machine learning algorithms shortening the time to receive advanced geophysical answer products from sometimes months, to live feeds directly from drills (Hopper, 2019). Alive, high speed, two-way data link between surface data acquisition systems and downhole geophysics tools has been established and incorporates calibrated surface measurements of dynamic forces directly on the drill string to match up with those measured downhole. Receiving live streams of natural GR and hole deviation surveys as the drill is drilling allows true remote decisionmaking with live data available anywhere in the world. The combined data from surface and downhole dynamics builds a data set that could begin to enable true optimisation of autonomous drilling processes.

Nov 8, 2021

By P Hartlieb, M Noeger, M Varelija

Rock bolts are important in underground mining as they provide support to the rock mass around the excavation. They are the most common reinforcement method in mining and civil engineering excavations. The length of the bolts, types and spacing between them can be varied, depending on the reinforcement requirements and the use case (Kolapo, Onifade and Praise, 2022). The rock bolt provides safety and stability for the rock mass in the excavation area and they can be mechanically anchored, grouted, or friction anchored. They normally don’t have a measurement option and there is a possibility that it failed without showing visible signs on the surface, especially in grouted rebar bolts where they can still have some residual strength. Therefore, support functionality can be lost without recognising it. To overcome that, sensors can be installed on all three previously mentioned bolt systems. Intelligent bolts with implemented measuring systems have a function of showing changes and indicating if there is some damage on the bolt. So, it can be said that intelligent rock bolts are regular bolts equipped with additional instruments which are helping us detect potential instabilities inside of the rock mass or malfunction of the bolt itself. Changes in rock mass can be tracked, by measuring rock bolt reaction concerning the excavation response. Rock mass damage and instabilities are therefore measured in terms of rock mass deformation. Moreover, other additional information depending on the type of the sensor device could be collected. Based on such measurements, information about rock mass state can be derived. Different rock bolt types work at different reaction principles. Therefore, limitations on sensor application and information that can be extracted must be considered.

Sep 1, 2024

By N McIntyre, R Trancoso, N Bulovic

Mining is essential for facilitating human development particularly as demand for critical minerals grows. However, over the mine life cycle, the environment is permanently changed. Once mining ceases, mine-affected land can leave significant legacy issues on the surrounding environment if not managed. Therefore, mine closure planning is critical. Mine closure occurs over large scales often with the aim of recreating resilient ecosystems over mined landscapes with mitigated negative impacts. The natural state of the landscape and the environmental risks over planning time-scales are largely driven by climate. Climate change is expected to impact different parts of the post-mining landscape, from stable landform design (soil erosion mitigation) to revegetation efforts and pit lake management. Consequently, mine closure plans may need to account for a non-stationary and uncertain future climate, that may be both different to the current climate and evolve during the mine life and post-closure. Here a new data-based approach is presented for incorporating climate change projections in mine closure planning, based on the recently released Coupled Model Intercomparison Project phase 6 (CMIP6) climate data used in the latest Intergovernmental Panel on Climate Change (IPCC) assessment report. The approach: (i) characterises closure-related attributes of the future climate, and (ii) identifies the amount (and direction) of change expected to occur, and its uncertainty, focusing on five metrics for demonstrative purposes and initially describing changes in erosive potential below. This provides information on the type of future environment (ie the changing baseline) that mine closure should plan towards, and identifies rehabilitation options that may be susceptible to increased risks from climate change.

Aug 2, 2023

By Messenger A. J, Miles J. G

A thermal neutron irradiation technique using a mCf neutron source has been developed and applied to thp.simultaneous determination of iron and aluminium (expressed as AI2O3) in iron ore fines (-6 mm particle size) on a moving rubber conveyor belt.While the determination of iron with this technique is based on the use of a NaI(TI) detector to monitor the characteristic prompt gamma rays (7.64 MeV) emitted by thermal neutron capture reactions in the iron, the etermination of AI2O3 is based on the use of a second Nal(Tl) detector to monitor the characteristic gamma rays (1.78 MeV) emitted after thermal neutron activation of the aluminium. The second detector is located downstream from the first. Although the speed of the conveyor belt has no direct effect on the iron measurements, it must not exceed about 3 m/min if good accuracy is required for the AI2O3 measurements. Consequently an auxiliary conveyor belt is required in order to avoid interference with normal ore processing.Dynamic trials of the technique, using 1500 kg samples of ore on a 460 mm-wide rubber conveyor belt moving at 1.7 m/min, have demonstrated that the method can achieve accuracies of 0.7% Fe and 0.1% AI2O3. At the present stage of development, it is recommended that lump ore be crushed to a particle size of 6 mm before analysis.In addition to iron and AI2O3 determinations, measurements of total moisture content and bulk density are possible. The determination of Si02 is also feasible, but a separate fast neutron source (e.g., Am-Be) and a separate gamma ray detector are required.

Jan 1, 1980