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Gwalia Consolidated Ltd has been in the mining industry for about 15 years, yet its key wholly owned Greenbushes Mine has a history dating back to the last century. Similarly Gwalia Consolidated's associate, Sons of Gwalia Ltd owns the historic Sons of Gwalia and Marvel Loch Mines with Sons of Gwalia celebrating its centenary this year. This durability is a testament to the quality of the orebodies concerned and the massive technological achievements over this time which have enabled each of these mines to maintain their competitiveness. While Sons of Gwalia and Marvel Loch were and continue to be gold mines, the wholly owned Greenbushes Mine has survived and in fact prospered through the development of alternative products from its rich and unique pegmatite. Similarly, for Gwalia Consolidated to grow and prosper it will be necessary to expand the current portfolio of products and operations. The Greenbushes Mine has already given Gwalia world `No 1' status in both the supply of primary tantalite concentrates and lithium minerals (spodumene). The asset base contributed by Gwalia's gold investments assisted in the recapitalisation of the Greenbushes assets to fully develop their potential. Industrial minerals and strategic metals were of interest to Gwalia as these markets are relatively small and it is possible to develop an influential if not dominant position in the market with a quality asset. Capital expenditure to develop such projects are also usually in the order of $10 m to $20 m, a manageable range relative to Gwalia's size.

Jan 1, 1996

By W Z. Liu, Q Q. Shi, H T. Yang, X L. Zhang

In order to improve the cutting blasting effect of dimension stone mining, the water coupling directional cutting blasting technology was put forward. Based on the test apparatus and special charge configuration, the mechanism of directional cutting blasting was analysed. Directional device changes the initial equilibrium of the total energy of shock wave effect on blasthole wall. The initial directional crack first appears in the blasthole wall that makes contact with the directional device. Then, two cracks are connected along the direction of the blasthole centre line under the action of detonation pressure and water wedge. The plexiglass tests showed that water coupling directional cutting blasting technology produced cracks along with the predetermined direction completely. The cutting surface was smooth and only a few short cracks appeared around the blastholes. It proved the validity of this technology.CITATION:Liu, W Z, Zhang, X L, Yang, H T and Shi, Q Q, 2015. Directional blasting rock cutting technology, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 815–818 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By T Rohde, P Defferrard

In 2010 a store and release cover (the cover) was constructed on the south waste rock dump (SWRD) at Century mine. This also included aerial seeding of province native trees and shrub seeds. The purpose of the cover is to reduce percolation into the potentially acid-forming (PAF) waste rock by maintaining a compacted reduced permeability layer (RPL) at near-saturated conditions. This is achieved by overlaying the RPL with a 1.5 to 2 m thickness of soil-mulch. The soil-mulch has a hummocky final surface that captures rainfall, so it does not runoff, allowing it in part to infiltrate, with excess water removed by evaporation and transpiration. The RPL is the trafficked surface of the SWRD.The unsaturated behaviour of the cover is being monitored by instrumentation including volumetric water content and matric suction sensors and a weather station capable of estimating evapotranspiration. The instrumentation allows for direct measurement of infiltration into the cover, storage of rainfall, percolation through the base of the cover and in situ soil water characteristic curves (SWCC).The key functions used to describe the unsaturated behaviour of the cover materials is the SWCC and the unsaturated hydraulic conductivity function. The SWCC is a plot of soil water versus soil suction. It provides the loci of moisture states of a soil from the saturated to the dry state.The paper presents the results of five years of monitoring. It shows that total infiltration into the top of the SWRD was about 1.6 – 3.7% of cumulative rainfall over five years, with most of the infiltration going into storage within the cover. Runoff from the top of the dump is not allowed therefore, the remaining 95% of the total rainfall was lost to evaporation or as lateral flow when infiltration reached the RPL. The paper presents some simple analyses of the wetting by rainfall infiltration of the cover, leading to breakthrough at the base. Field data are used to support the analyses.Presentation of the SWRD water balance is also included in the paper using SVFLUX™GE which is a finite element model that simulates water transport through a saturated or unsaturated medium.CITATION:Defferrard, P and Rohde, T, 2018. Five years of cover performance monitoring and modelling for a store and release cover at Century Mine, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 179–189 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By M I. Roberts

As Australia’s mining industry painfully retrenches, mining executives and managers strive to remain viable by seeking significant productivity increases directly through process improvement and indirectly by improving leadership and workplace culture, the most powerful determinant of productivity. Culture is the combination of people’s attitudes and behaviour, together with leadership values and focus.Comprehensive new and automated data collection and management systems promise much for improving productivity, yet despite rapid advances in measurement and sharing of data, the use of data can reduce productivity unless behavioural aspects are considered and designed as part of implementation. This is because systems drive behaviour that in turn shapes attitudes to determine culture.Experience from many mine sites and other industries in three countries confirm that the most powerful drivers of people’s behaviour are the Measurement-Analysis-Reporting system and business leadership.This paper discusses fundamentals of practical, statistically valid process measurement, analysis and reporting systems before discussing associated leadership considerations for sustained improvement in safety, productivity, employee retention, leadership, accountability and commercial returns.The key to productivity improvement is improving core processes and important support processes. In turn, the key to process improvement is identifying the major process components and their interaction by measuring and then analysing their variation and level of performance. Understanding variation is often neglected yet is usually highly significant. It is essential that the fundamentals of statistically valid yet practical process and data analysis are understood and incorporated into system design to ensure productive, informed behaviour.The design and use of Measurement-Analysis-Reporting systems influences behaviour most profoundly and determines people’s effectiveness. Behavioural aspects are detailed by focusing on six primary drivers of human behaviour and five basic systems for managing businesses. These are integrated in a seven-step process and productivity improvement methodology that combines statistical, analytical, systems and behavioural factors.The paper includes development, implementation and tracking of a project plan for improving management and leadership systems to drive aligned behaviours. This key leadership responsibility is essential for improving performance to get the most from capital while providing people with the opportunity to develop greater autonomy, which is essential for self-discipline, responsibility, initiative and accountability.CITATION:Roberts, M I, 2015. Integrating measurement, systems and leadership to build safe, productive cultures, in Proceedings Third International Future Mining Conference, pp 73–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By B Shi, Y Li, L Ma, F Zhou

Subsurface fires are a common threat to coal mining, as spontaneous combustion of coal can potentially result in gas combustion and explosion. Fire-proof techniques, such as grouting, foam, or colloid injection, are not in a position to function ideally, due to the limited coverage and stopping the extinguishment substance from reaching the fire location. Liquid nitrogen, as a kind of all-submerged fire prevention or extinguishing method, can rapidly extinguish fires, thus preventing gas explosion and minimising extinguishment time. Injecting liquid nitrogen through boreholes is an important way during the period of mine catastrophe. But liquid nitrogen is not effective enough in infusion; technical issues restrict the development and utilisation of liquid nitrogen fire prevention and extinguishing technology. Immediate infusion of liquid nitrogen is usually associated with ‘air slug’ (the balloons and bubbles in the pipeline which hinder the flow of low-temperature liquid), which blocks pipelines for liquid nitrogen injecting. Another issue is that the pipeline tends to be damaged due to freezing, which undermines the injecting efficiency of liquid nitrogen and its application result. In order to solve the problems of the low efficiency and some other related field issues in liquid nitrogen perfusion, the ground–underground high efficiency liquid nitrogen injection technology were developed. Implementation of liquid nitrogen infusion techniques in Chinese coalmines achieved the goals of fire prevention and air-cooling. The technique presented in this paper is efficient in absorbing heat, and consequently, displacing oxygen and combustible gases. Field tests at Rujigou and Yangchangwan Coalmine justified the efficiency of the technique. By using this technique, there was no waste left behind, which may impede the subsequent production. The presented technique is of great benefit to the social, economic, and environmental aspects of mining operations, and will have broad applications in fire prevention for large-scale coalmines.CITATION:Zhou, F, Shi, B, Li, Y and Ma, L, 2015. Key techniques and engineering applications of stereoscopic liquid nitrogen infusion for coalmine fire prevention, in Proceedings The Australian Mine Ventilation Conference, pp 291–298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By H Khoshrou, A Siamaki

Blast designs can have productive and non-productive impacts on downstream stages, mine productivity and operating costs. On the other hand, ground vibration, fragmentation, and back break caused by blasting impose damage and financial penalties and which must be controlled by blast design. One of the significant variables in blast design is the burden. In this study, the potentials of artificial neural network are investigated in prediction of burden in the Sungun copper open-pit mine. Input data were assembled through 18 blasting blocks according to different levels and experimental geomechanical investigation. To construct the model blastability index, uniaxial compression strength, hole diameter, specific weight of rock, rock quality designation and cohesion strength are taken as input parameters, whereas, burden is considered as an output parameter. Mean square error was used as the performance function and back propagation algorithm as the training function, containing four hidden layers and 14 data sets. Four sets of data were used to make sure that correct training had been carried out. This produced the coefficient correlation of 0.662.

Sep 26, 2011

By P Craig, I Canbulat, J Naylor, J Emery, A Sykes

Longwall mining is by far the most common method of underground coal extraction in Australia. Industry trends and expectations are placing increasing emphasis on the reliability and productivity of these operations. Longwalls are becoming wider and longer while retreat rates are continuously increasing due to significant improvements achieved in longwall equipment reliability and automation. This increased longwall productivity is placing significant emphasis on the reliability of longwall panel development.Although there have been significant improvements in the reliability of continuous miners and hydraulic drill rigs, the traditional resin-encapsulated bolt installation is still the principal method used in all major coal producing countries around the world. Anglo American realised that an opportunity existed to introduce an alternative roof bolt installation technique called ‘spin-to-stall’ (STS) into Australia. STS was first introduced by Anglo American Coal in South Africa, where it has been successfully used for over a decade, though implementation of South African STS resin in Australia has proven to be near impossible. Therefore, a new STS development project was initiated between Anglo American Coal and Jennmar Australia. This paper summarises the journey of this project, the results achieved and the successful implementation of STS at Grasstree mine.CITATION:Emery, J, Canbulat, I, Craig, P, Naylor, J and Sykes, A, 2014. Development and implementation of spin-to-stall resin at Anglo American’s Australian Underground Coal Operations, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 287–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

Carbon sequestration in planted forests provides an immediately available, low cost option to address the greenhouse impacts of coal mining and coal utilisation in a carbon constrained world. In addition, planted forests also offer the opportunity to address other environmental issues, particularly salinity and loss of biodiversity. Given salinity is characteristically associated with agriculture in the 500 to 700 mm rainfall belt, then where such forests can also produce commercial timber products, they offer the additional opportunity to establish new, diversified rural employment in both timber growing and processing. In the majority of Australian catchments affected by salinity, where rainfall is generally less than the 700 mm limit to conventional forestry, and where groundwater reserves are often saline, the objective of achieving economically viable forestry production presents a significant challenge. In 1996, Saltgrow commenced a collaborative breeding program to combine the salt and stress tolerance of E camaldulensis, with the growth rate, stem form and wood properties of the commercial species, E grandis and E globules. This program aimed to produce trees with the potential for commercial rehabilitation of saline landscapes. Results covering a range of site conditions from SaltgrowÆs network of over 100 trials around Australia are presented. The opportunity for commercial plantations integrated with agriculture in low to medium rainfall areas to address salinity and sustainability will be discussed. In addition, the significant potential for partnerships between land-rich, cash-poor farmers, catchment management authorities seeking to invest in public good projects that enhance environmental sustainability, and major carbon producing industries with either mandated or voluntary requirements to curtail net emissions will also be discussed.

Jan 1, 2005

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

By Z Fu, E Topal, O Erten

"Mine waste rock management involving waste rock movement and placement, is a critical aspect in the planning of open pit mining operations, as the waste rock haulage cost can be the largest portion of the mine operating cost. The concept of sustainable development in the mining industry also encourages environmentally friendly waste dumps that have zero hazards to people and the surrounding environment. Therefore, a detailed waste management schedule must satisfy economic and environmental considerations. However, the available tools in the market cannot provide optimal waste dumping schedules to meet all these constraints. This paper introduces a user-friendly and automatic tool to optimise the waste dumping schedule, which minimises the haulage cost, and covers the encapsulation of reactive materials to minimise acid mine drainage problems. This tool has been developed by using a new mixed integer programming (MIP) mathematical model that considers both single-lift and multilift dumping scenarios. The application of the proposed tool on a data set collected from a gold mine shows that the multilift dumping scenario has provided a more flexible and economical waste dumping schedule than the single-lift scenario, and both scenarios satisfy environmental requirements.Citation:Fu, Z, Topal, E and Erten, O, 2016. A Modified Software Tool for Mine Waste Rock Dump Planning, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 229–242 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By J L. Stacey

The diverse priorities, drivers and concerns of multiple stakeholders in the minerals industry complicate the integration of sustainable development considerations into mine design, as well as operational and strategic decisions. The ability of the industry to address all role-playersÆ needs, or indeed, to achieve consensus among all role players on the plethora of sustainable development issues seems a noble yet unattainable goal. One of the difficulties in assessing the relative importance of sustainable development issues across many stakeholders is the inevitable lack of impartiality in valuing these issues. Starting from a premise that transparency and fairness of the process are absolute prerequisites for progress, but that consensus is not, an approach has been developed in which all stakeholders are asked to assess the importance of all other stakeholdersÆ priorities, excluding their own. The approach recognises that stakeholders have different levels of contribution, understanding, vested interests, and perceptions of legitimacy and entitlement, across the diversity of sustainable development issues and decision criteria. Using Triangular Value Analysis, the relative weightings of each of the stakeholderÆs priorities are determined through a regression-like technique. The uniqueness of this approach is the manner in which self-assessment bias and overemphasis of stakeholdersÆ own priorities are avoided. The methodology can be used for both internal and external stakeholders, and in conjunction with other group decision making techniques, such as the nominal group or Delphi techniques. This paper will illustrate how Triangular Value Analysis may be applied in the minerals industry to determine priorities in various decisions relating to potentially conflicting sustainable development priorities within the industry.

Jan 1, 2009

By S Wotherspoon

At Kalgoorlie Consolidated Gold MineÆs (KCGMÆs) Fimiston Operations, located on the periphery of Kalgoorlie Boulder in Western Australia, roughly 7.5 million tonnes of rock are broken each month for the extraction of gold. With the close proximity of neighbours to the mining operations in the Chaffers Cut Back, special blasting techniques and tools were employed by KCGM to manage the blast induced vibrations and noise in this area. The i-konTM initiation system coupled with OricaÆs complementary modelling and analysis tools offered the complete blast management package. With these tools KCGM management and Orica Mining Services commenced an investigation into the benefits of electronic initiation. Prior to the commencement of electronic blasting, initial modelling was conducted to examine the vibration time waveforms and their frequency content, as these were expected to have an impact on vibration interaction with structures such as large buildings and urban dwellings. This work looked at results measured for a previous conventionally (pyrotechnic) initiated blast in the area and compared it to the results obtained when the blast was modelled with electronic initiation and faster timings. The predicted peak particle velocity (PPV) and structural vibration factor (SVF) were calculated. From the results it was concluded that the investigation into using i-konTM electronic initiation system and SHOTPlus«-i blast design software had some real potential to improve blast vibration management on the cut back. The use of the electronic initiation system and complementary software allows intricate timing designs to be accurately placed into blasts. The system has a number of working modes that allow either the precise design timings to be logged automatically into each detonator or to be manually logged where a variation from the design exists. Where such variations from the design occur, the electronic system permits the actual timings used to be uploaded back into the design file. This allows both design and real actual timings to be stored for future analysis or reference.

Jan 1, 2004

By M Field

Kimberlite pipes, as opposed to dykes, sill and secondary deposits, are the primary target for diamond exploration companies because they have simple geometries and can contain large volumes of potentially diamond-bearing ore. Once discovered, important decisions have to be made regarding the sampling of these geological entities to establish the total volume of ore present, and to define the internal geology, which can be complex in nature and controls the distribution of diamond grade. It is essential that as part of this process the uncertainty in constructed geological models are assessed. In this paper the Orapa AK1 kimberlite pipe in Botswana is used as a case study to explore a potential methodology for defining this uncertainty. The uncertainty of the rock volumes of different types can be characterised by a geostatistical approach. Geostatistical simulations, based upon a plausible representation of the geological bodies, provide different possible images of the orebody that can be considered as different realities. By testing different borehole layouts and drilling the orebody virtually on the computer, many different, but equi-probable realisations of the pipes can be produced. It is then possible to estimate the rocksÆ volumes and compare them with the actual ones. A statistical analysis of the relationship between estimation error and the number of boreholes can then be used to optimise the next sampling campaign. The rock volumes are obtained from a two-step simulation process. Firstly, the pipe geometry is simulated by means of introducing variations around the geological block model, by an original method called centre point simulation (CPS), which has been developed for this purpose. Secondly, the internal geology is then simulated within the pipe. The methodology for simulating the internal geological zones has to be adapted to the level of information and to the geological structure itself. The upper portion at Orapa AK1 is filled with sedimentary crater facies. Here plurigaussian simulation techniques can be applied that are adapted to the simulation of sedimentary facies. The central zones of the pipe are typically subvertically-oriented massive volcaniclastic deposits and breccias and the lower regions comprise a complex root zone. CPS is appropriate for these zones.

Jan 1, 2006

By O van Baalen

The Ernest Henry Mine is a copper-gold open pit operation situated in northwest Queensland, Australia. It is owned and operated by Xstrata Copper, with a current throughput of 11 Mtpa, however, open pit operations are scheduled to cease in mid 2011. The deposit dips approximately 45º and extends for at least another 400 m vertically below the final 530 m deep pit design.Construction and development of a sublevel caving (SLC) operation beneath the open pit was approved in December 2009. The feasibility design requires 39 km of development to be completed prior to production, which will commence in the fourth quarter of 2011. Initial ore production will be trucked and will increase to 3 Mtpa by the end of 2012, after which a hoisting shaft will be used. Ore production will then increase to 5 Mtpa in 2013 and ultimately to 6 Mtpa in 2016.Two 3000 kilo watt of refrigeration (kW(R)) modular refrigeration plants will be installed, as well as two 1600 kW mixed-flow fans capable of a combined flow rate of 780 m3/s at a total pressure loss across the mine of 2000 Pa. The main fans will be installed underground and will exhaust into the base of the pit.The following challenges were faced in the development of the ventilation and refrigeration network:•a relatively steep geothermal gradient,•tropical ambient conditions,•working under a wide pit shell, and•a large underground trucking fleet prior to shaft commissioning.A considerable number of ventilation studies were conducted with later studies extensively using Ventsim Visual™ mine ventilation software to complete the design process of the ventilation and refrigeration networks, including the comparison of several alternative designs. The paper focuses on design challenges prior to the commissioning of the hoisting shaft, and discusses resistance optimisation and occupational hygiene-related design parameters, such as heat and diesel emissions, production level ventilation, main fan selection and location, and refrigeration requirements.

Mar 21, 2011

By Marshall T. E, Finfinger G. L

Gulf Coast domal salt mining operations have had sporadic encounters with methane gas emitted without any warning. In virtually all confirmed cases, the methane was localized in methane enriched zones. In a few cases large quantities of methane were expelled rapidly with salt outbursts, resulting in dangerous methane concentrations. Estimates of methane liberated by face blasts in methane-enriched areas is needed in determining how much air should be supplied to the face for proper dilution. A relationship between the gas content of salt samples collected from the face and the amount of methane liberated would be helpful in estimating how much methane will be produced by a face blast. Little is known about the layering or stratification of methane in large area-low velocity airways. This publication reports on three tests conducted by the Bureau of Mines which monitored the immediate return air of four faces during blasting. The test locations were in a methane gas-enriched section that had previously experienced two large outbursts and many smaller ones. A comparison was made between gas content values of face salt samples from the dissolution test and the gas liberation quantities. The characteristic movements of the methane in a large room with low air velocities were charted. This will help to better understand the factors involved in proper placement of methane sensors as a warning system.

Jan 1, 1988

By Y Xu, J Hacker, D J. Williams

Shear strength parameters of compacted clay liners are needed to analyse the stability of mine waste dumps containing compacted clay liners as sealing layers for potentially acid forming waste rock. A representative clay sample was supplied by McArthur River Mine from the mine site in the Northern Territory, Australia, with an average as-supplied gravimetric moisture content of about 13.6%. The clay was compacted in a 100 mm by 100 mm direct shear box at the as-supplied moisture content to a dry density of 1.85 t/m3, representing the field compaction specification adopted by the mine. To determine the peak and ultimate shear strengths of the compacted clay, single-stage direct shear testing was carried out at nominal initial normal stresses of 50 kPa, 100 kPa and 200 kPa, representing shallow depths of burial in the North Overburden Emplacement Facility of about 2.8 m, 5.6 m and 11.1 m, respectively (assuming a waste rock wet unit weight of 18 kN/m3). Three shearing rates of 1 mm/min (rapid), 0.1 mm/min (intermediate) and 0.01 mm/min (slow) were applied to study the influence of shearing rate on shear strength. In addition, the development of a residual shear plane was tested by reversal and re-shearing in the direct shear box. In the first shearing, the peak and ultimate shear strengths are determined. The normal load was then removed and the box rewound to its starting position. The normal load was then re-applied and the specimen re-sheared. Two reversals were applied to each specimen, and it was found that there was no significant reduction in shear strength. Finally, based on a range of shear strengths obtained in the laboratory for McArthur River Mine clay and other materials by various laboratories over time, shear strength parameters for the compacted clay were recommended for use by the mine.CITATION:Xu, Y, Williams, D J and Hacker, J, 2018. Shear strength of compacted clay liner at McArthur River Mine, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 208–219 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The weathering profile, in arid terrains, is commonly capped by different kinds of hardened crust, whose formation is related to recent or former climates. One may distinguish silcretes, calcretes and the ferruginous (or ferro-aluminous) laterites. the present keynote address mostly deals with the lateritic regolith and, moreover, the influence it has on mineral exploration. The lateritic regolith, also called "cuirasse", is a result of a massive accumulation of Fe (and/or Al) oxides on top of weathering profiles developed during former, probably seasonal humid, climatic episodes, and whose preservation depends on the characteristics of later climates. The total thickness of such weathering profiles commonly exceeds 50 m, with an almost complete substitution of the rock forming minerals by secondary minerals as kaolinite and Fe-Al oxi- hydroxides (hematite, goethite, boehmite, gibbsite). Such an alteration of the primary minerals assemblage is of course accompanied by significant changes of the chemical composition, as concerns major and trace elements. The latter are distributed amongst the main secondary mineral phases or trapped in some primary resistant minerals, but may also be leached, totally or partially. Gold is also affected by lateritic weathering, as shown for instance by morphoscopic and geochemical studies of gold grains collected in the different horizons of the profile, which indicates some dissolution followed by reprecipitation.

Jan 1, 1988

By H Zhang, M Karimi, M Hassan, S Saydam, B Li

With the prevalence of Mine Internet of Things (MIoT), different types of sensors have been widely deployed in mine sites for environmental monitoring and operational management. Currently, sensors in mine sites are mainly powered by cables or batteries. However, the deployment and maintenance of a power supply network can be difficult and expensive, and batteries have a limited lifespan. The vibration energy harvesting (VEH) technology can be used to provide power for lowpower sensors in mine sites. This presentation briefly introduces three widely used VEH methods (ie piezoelectric, electromagnetic, and electrostatic). The performance of a commercial electromagnetic energy harvester (ReVibe model D) is evaluated based on the vibration of a lab vibrator (3 g, 50 Hz) and an idling SUV automobile (0.3 g, 25 Hz). Experimental results indicate that a ReVibe energy harvester can generate adequate electricity to power a sensor, and its power output depends on the load resistance as well as the vibration frequency and amplitude of vibration sources. To apply VEH to mining applications, this study also analyses the characteristics of vibration sources at the mine site based on the vibration data collected from various operating machines in a coal handling and preparation plant (CHPP). The vibration analysis results indicate that all the measured vibration sources in the CHPP can generate stable and abundant vibrations, characterised by substantial amplitudes (up to 5.55 g) and low dominant frequencies (ranging from 14 Hz to 25 Hz), which are sufficient for VEH.

Sep 1, 2024

By G Lane, M Bueno

In a recent publication (Bueno and Lane, 2011) the authors presented the analysis of a consolidated dataset composed by 137 autogenous/semi-autogenous grinding (AG/SAG) mill pilot trials. By comparing the measured data against theoretical specific energy consumption, the analysis indicated which circuit configurations were more or less energy efficient. However, the analysis has also indicated that the energy efficiency of each of the types of circuits vary significantly.There are numerous factors that contribute to the variations of energy efficiency of AG/SAG mill-based circuits, such as feed size distribution, recycle ratios and ore characteristics. In view of this, the present work accesses these factors individually and discusses what may lead a particular circuit configuration to be more or less efficient in terms of energy and costs.CITATION:Bueno, M and Lane, G, 2012. Key drivers of energy and cost efficiency in autogenous/semi-autogenous grinding circuits, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 113-118 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

THE slag from the blast furnaces having been granulated, a representative sample is taken to the sample mill. It is then dried, crushed through a 100-mesh screen, intimately mixed, and packeted for assay purposes.METHOD OF ANALYSISINSOLUBLEWeigh 1 grm. of the finely-pulverized slag into a 3t-in. casserole, moisten with a little water to prevent sticking, cover with a clock glass, and add 20 cc. of hot acid (1 HNOs, 3 HCI, 4 H2 0). Evaporate slowly to dryness on a hot plate and bake (without overheating) until all the gelatinous silica is dehydrated. Cool, add 20 cc. HCI (1-1), and boil gently for several minutes; filter into a 300-cc. beaker, cleaning out the casserole thoroughly with a rubber-tipped glass rod. Wash residue with hot distilled water and transfer it to a No. 1 porcelain crucible. Dry, ignite, cool in a desiccator and weigh as total insoluble matter. Dilute filtrate to 200 cc. and neutralize some of the excess HCI with NHa.OH. Warm, and pass H2S for 15 min. Filter and wash withhot water. Boil off H2 S, oxidize with 5 cc. HNOll , reduce bulk of the solution by evaporation. to about 100 cc., and transfer to a 250 cc. flask.SILICAFuse insoluble residue over a blast lamp in a platinum crucible with three or four times its weight of anhydrous carbonate of soda, for 10 to 15 minutes, or until decomposition is complete. Cool, and extract fusion in an 8-in. evaporating dish with HCI (1-1); rinse crucible and cover with distilled water, and evaporate to dryness over a water bath. Take up dry mass with 10 cc. strong HCI, and then.

Jan 1, 1922