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Entry of personnel under a vertical raise bored hole is not standard practice in Australia. Where access is required below a rise, mining operations must be confident that they understand the capacity of the ground control specified and installed. Physical modelling was conducted on Callie mine to evaluate the performance of 5 mm steel wire weldmesh secured to the base of a vertical raise bored hole of 1.4 m diameter. Joint orientation data was used with Unwedge to calculate a series of potential wedges likely to form within the rise. The mass of the most likely wedges were then replicated by collecting rocks in 5 kg increments (¦10 per cent), which were allowed to freefall onto installed mesh at the base of a 40 m vertical rise. The results indicate that two sheets of mesh can retain a freefalling rock of at least 20 kg mass although rupture of strands can result. This paper outlines the test conditions, expected results based on theoretical calculations and actual outcomes of the testing.

Nov 25, 2010

By K Kermanshahi, J Allen, MáHilden, M Powell, S Mwansa, S Palaniandy

Approximately 420 VertiMills« (VTM) have been installed in mineral processing plants throughout the world, mainly in tertiary and regrind applications plus several in secondary grinding duties. Metso Minerals (Metso) and the Julius Kruttschnitt Mineral Research Centre (JKMRC) have commenced a collaborative research program in stirred milling technology focusing on mill performance evaluation, model development and scale-up methodology. Industrial VTMs are being assessed using a consistent circuit survey protocol to evaluate the performance of VTMs in comminution circuits. The survey protocol includes identification and modification of sampling points, appropriate sampling techniques, controlled circuit stability, and best sample analysis practice. To initiate this study four surveys were conducted in the tertiary grind circuit in the Ridgeway Concentrator at Cadia Valley Operations (CVO) that treats the full circuit throughput of over 800 tph. To deal with the high feed rate the site opted to lead the world in the application of stirred mills by installing the largest VTM, at 3000 hp (2240kW) in closed circuit with a hydrocyclone bank. On average the operating work index was 13.1 kWh/t, reducing the secondary grind product by 40 - 50 ¦m to the required 80 to 100 ¦m range. The applied specific energy is relatively low in these low-intensity stirred media mills at 2.7 kWh/t. The size specific energy was 24.2 kWh/t-75¦m. Based on the survey and operating data the VTM circuit is performing well in this high-throughput tertiary grinding application, producing a sub-100¦m product.CITATION:Palaniandy, S, Powell, M, Hilden, M, Kermanshahi, K, Allen, J and Mwansa, S, 2013. VertiMill« - Development of circuit survey and performance evaluation protocols, in Proceedings MetPlant 2013 , pp 162-175 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By A Coelho, D Bruce, H Grosser, C Parken, M Xia

Carrapateena is a new underground sublevel cave mine and was officially opened in 2020. It has a mine life of 20 years. Development began in 2016, and with the rare opportunity to start a with a blank canvas and having a long mine life, an effort was made to explore how to incorporate innovative and leading-edge technologies. The Ventilation on Demand (VoD) system was designed with the objective to optimise power consumption and ventilation delivery through the primary and secondary ventilation systems. Primary fans controlled by Variable Speed Drives (VSDs) and dualwinding secondary fans with multiple setpoints control the delivery of overall quantity. Automated butterfly dampeners control the regulation of air to individual production crosscuts, and automated louvres control the exhaust quantities from the mining levels. Ultra-sonic flow sensors are installed to measure air quantity and environmental stations are installed to measure air quality. Both are designed to play a key role in control and calibration of the system. It was quickly identified that no one vendor could provide a holistic solution to meet the design requirements. A strategy was derived to use multiple vendors, harnessing the specific strengths of each. A control system has been developed to allow the Site Operations Control Centre (SOCC) to oversee and control real-time delivery of ventilation as required by operations. The first full level installation of the VoD system was completed in September 2020.

Mar 15, 2021

By D Reid, J Black

The adverse health impacts from diesel particulate matter (DPM) exposure are a well-known global concern. The building evidence has triggered underground mining operations to review existing atmospheric conditions and assess the scale of the challenge faced. South32’s Cannington Mine (Cannington) evaluated the ability to provide a healthy atmosphere from a whole mine approach, taking into account existing preventative controls including: maintenance strategies, fuel quality, mining operations, ventilation provisions, monitoring protocols and effective education and training programs.During the evaluation process, Cannington gave due recognition to the advice and guidance provided in the Queensland Guidance Note 21 (QGN21), the Guidelines of New South Wales’ MDG29 and Mining Industry Advisory Committee (MIAC) of Western Australia. Each of these documents advises a dilution rate of >0.06 m3/s/kW is best for reduction of DPM exposure in underground mines.Achieving the prescribed mine ventilation rate typically results in the need to directly invest significant capital into increasing ventilation infrastructure in order to further dilute contaminants. In today’s economic market of volatile metal prices and increasing pressures to meet regulatory requirements, it can become challenging for established metalliferous operations to create a balance between optimisation of current ventilation infrastructure and capital outlay.In order to obtain and correctly justify the requirements for capital investiture Cannington conducted a ventilation operational analysis for the life-of-operation, identifying the existing air volume envelope was adequate for current and future production rates by optimising existing primary ventilation infrastructure through the implementation of a modified ventilation on demand (VoD) and air conservation system.This process achieved sustainable operating and capital cost reductions without compromising delivery of adequate ventilation to work areas. The process also recognised that engaging mine workers’ ownership of their work areas is crucial to maintaining a technically efficient and operationally robust ventilation system.This paper will concentrate on Cannington’s existing preventative controls, their implementation and their management for the prevention of increased DPM exposure; reducing the risk of both short and long-term health impacts to ‘as low as reasonably achievable’ (ALARA).CITATION:Black, J and Reid, D, 2017. Delivering a healthy atmosphere underground in a cost-conscious environment, in Proceedings Australian Mine Vent Conference 2017, pp 159–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Y Chung, B Choi, H Lee

Numerous studies have explored refractory corrosion in the presence of slag and/or metal, utilising the Finger Rotating Test (FRT). Recent experimental results revealed that corrosion initially increased with rising rotation velocity but was then suppressed above a critical rotating speed, under conditions involving a two-liquid solution of slag and molten steel. This phenomenon indicated that the liquid/liquid interface movement occurred during spindle rotor. However, understanding of the phenomenon, known as the rod climbing effect, remains inadequate in the case involving slag, molten steel and refractories. To gain deeper insights, a simulation experiment was conducted on the phenomenon using silicon oil/water and the phenomenon was analysed using computerised simulation software (Ansys Fluent). Experimental modelling demonstrated that interfacial movement occurs even at low rotation velocity, as low as 200 rev/min, when the viscosity of silicone oil is at 100 cP. Computational analysis utilising the Volume of Fluid (VOF) method and a realisable k-ε turbulence model elucidated that interface elevation during rotor rotation arises due to viscosity disparities between the two fluids. Furthermore, this movement is more pronounced when the viscosity difference is lower. Additionally, the study findings suggest that higher density differences between two liquids suppress the phenomenon of interface movement.

Jun 19, 2024

By Merritt RR

The equilibrium phase relations in the Fe- Mn-Ti-0-S system were established at 1380 and 1485 K. The elemental distributions between the equilibrium phases were obtained by chemical- ly analysing selected samples from the phase study. The results are considered in relation to the coal reduction process for upgrading ilmenite. The beneficial effect of adding sulfur to a kiln that uses a manganese-rich feed is ex- plained by the formation of a metal-sulfide solid-solution phase that removes part of the manganese from the oxide system. The optimum conditions for operating the reduction kiln are determined, and the practical need to operate the kiln at other than optimum conditions is explained. It is shown how the experimental data can be used to predict the best compromise conditions for reduction and the resultant purity of the product.

Jan 1, 1980

The problems associated with achieving adequate accuracy for on-site axial flow fan performance measurements are discussed. The ability to test accurately rests heavily on equipment and installation design detail.Aerodynamic performance trials frequently cannot be carried out due mainly to the poor standard of installation design. In a majority of cases this results in unsteady, non-uniform inlet flow conditions to the fan. Details of installation design features and instrumentation, necessary for successful testing, are given for different types of installations and methods of testing. These cover both conventional practice, and new innovations which can provide solutions to difficult problems. Quantitative aspects of flow measurement are considered for various fan and duct configurations.Although the main emphasis is on large primary mine ventilation units which require on-site testing, the principles outlined have wide application to many other types of fan installation.

Jan 1, 1973

By Jia X

Three-dimensional microscopic modelling techniques involving specific calculations based on direct computation of the Brownian, van der Waals, Born, electrical double layer repulsion, bulk, hydrodynamic and external forces (gravity, magnetic etc) acting on and between each particle in a mineral dispersion are now feasible using advanced computer processor architectures. This contribution surveys the hardware requirements, the advantages and limitations of the approach for enabling prediction of dispersion behaviour a priori. The notion of developing a generic particle simulator, akin to the use of molecular modelling in the area of drug design, based on inputting process-relevant data (solution chemistry, mineral solids properties, hydrodynamics etc) is discussed. The methodology is illustrated with application examples involving: predictions of coagulation of mineral fines; shape and size of magnetically-flocculated hematite; and the kinetics of fouling of membrane surfaces and walls.

Jan 1, 1993

By K Lee, L Mann, J Bygrave, G Sheldon

Ausmelt is supplying commercial quantities of an alkyl hydroxamate flotation collector AM28 for flotation of oxide and supergene base metal ores and tailings. AM28 is a non-hazardous product used as a ten per cent to 50 per cent solution in dilute potassium hydroxide. It is a selective flotation collector for oxide or oxidised base metal minerals and replaces conventional sulfidisation for oxide mineral flotation. At Radio Hill, the AM28 is used in conjunction with traditional sulfide collectors, which allows simultaneous flotation of oxide and sulfide copper minerals. The Fox Resources Radio Hill copper concentrator near Karratha, Western Australia, is currently configured to treat supergene copper ore sourced from the West Whundo open pit. This Archean VMS type copper deposit has been deformed and remobilised with uplift, erosion and weathering to form a significant supergene zone. The sulfide copper minerals present in the upper zone are digenite and chalcocite with lesser chalcopyrite and covellite. Oxide copper minerals present include cuprite, with lesser malachite and azurite. Gangue minerals include quartz, talc and chlorite. Plant trials at Radio Hill are reported for supergene West Whundo ore, where the AM28 was stage added into the circuit at nominally 80 g/t. Plant data over three months shows the copper recovery increased consistently from around 50 - 60 per cent to above 70 per cent when AM28 was added. This has been proven statistically. The grade of the concentrate was consistent with and without AM28, at nominally 22 - 24 per cent copper.

Jan 1, 2007

By A S. Fogliata, L Bengochea, G Mas, J E. Lazarte

The Culampajß auriferous district is located in the northern sector of the eastern edge of the homonymous hill, Catamarca Province, Argentina. Tajo Largo mine is situated in the southern flank of Las Minas gulch at an approximate height of 3.600 m above sea level. In the studied area main outcrops are orthogneiss rocks of Chango Real Formation. The ore mineral is native gold with a lesser amount of pyrite, chalcopyrite, haematite, limonite, malachite, azurite and covellite. These ore mineral assemblages are disseminated in quartz veins filling tension fractures in the host orthogneiss.Several types of inclusions have been recognised, including three phase H2O-CO2liq-CO2vap inclusions, polyphase inclusions with H2O-CO2 and one or more solid phases, and two phase aqueous inclusions. In the three phase H2O-CO2liq-CO2vap inclusions the Tmclath is about 1¦C and the CO2 liquid-vapour homogenisation occurs at 26 - 28¦C, to liquid phase. The homogenisation temperature of H2O-CO2 occurs at 365 - 380¦C in the aqueous phase. This set of data defined a solution with a salinity of 14, 4 wt per cent NaCl equivalent and a density of 0.84 g/cm3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4¦C and the eutectic point (Te) in -38¦C indicates a salinity of about 7.5 wt per cent NaCl equivalent, with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260¦ and 280¦C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).

Jan 1, 2008

By C W. Davis

Every diesel engine emits approximately 100 million nano diesel particles (nDP) per cubic centimetre of raw exhaust. Each nDP has a diameter of between 50 and 70 nano metres or 1/100th the size of red blood cells (diameter of between 6 and 8 microns). When inhaled, some nDP pass through the lungs and penetrate all body tissue [1]. Europe and North America have recognised and are addressing the long term health problems posed by nano diesel particulate matter (nDPM) across their societies [2.3]. Australia has been slow to recognise the issue, at both a societal and mining industry level. There are chronic health effects for every underground miner and serious legal issues for mining companies with increasingly stringent Occupational Health and Safety legislation being implemented at a state level across Australia. This paper will review progress within Australian society and more particularly the underground hard rock mining industry, particularly in Western Australia (WA).

Mar 15, 2021

By P Viljoen, A Holland, C Parken

In the raisebore industry, there are two known methods of removing large diameter reamer heads once the reaming of an underground shaft is complete: 1. Lower the reamer head to the base of the shaft and use a thermal lance to cut the drill string and drag the reamer away from the hole. This method exposes the person doing the job to falling rocks from the unsupported mineshaft, a hazard which is difficult to control and has caused fatalities. 2. Install breast plates in the backs above the reamer head at the top of the hole, and use air hoists to lift the reamer out of the hole. Steel beams are then placed across the hole which the reamer is lowered down onto, dragged forward away from the hole, disassembled, and removed. This method is time consuming, expensive, and complex in the controls required to ensure safe completion of the job At Carrapateena, the air hoist method had been successfully used, however, with the cost involved and the complexity of this process, development of an improved and fit for purpose reamer removal method was pursued. OZ Minerals collaborated with Pybar to develop an industry first application of Enerpac SL100 lift and shift technology; a track mounted system with hydraulic lifting units that can both lift the reamer out of the hole and tram it back along the tracks away from the hole. A key component of turning the idea into a reality was by establishing a truly collaborative relationship between client and contractor. When the SL100 mobile gantry arrived, it was set up in Adelaide and trialled with the whole raise bore crew attending the two-day workshop and risk assessment; a rare opportunity for drillers. There have now been five successful reamer removals with the SL100 mobile gantry at Carrapateena. It has proven to be an efficient process with the entire process from setup to demobilisation taking less than 48 hours. This new way has completely removed hot works and uncontrolled hazards from working at the bottom of a shaft. It has also saved the reamer stabiliser from being cut and thus wasted. Exposure to the open hole has been minimised significantly as assembly of the SL100 is completed well forward of the open hole. This new process is exponentially safer, quicker and cheaper.

Mar 15, 2021

The Porgera gold mine has made significant progress with the successful installation of a JK FrothCam image analysis system. The system is used to measure and control froth velocity on the scavenger circuit which has brought significant economical and operational benefits. The froth velocity signal, determined by analysis of the camera, is transmitted to the PLC that manipulates flotation cell airflow rate and cell level controllers to maintain a target froth velocity of 130 mm per second. Following on from a three-week trial installation in June 2000, a permanent installation was commissioned on the scavenger Outokumpu (OK150) tank cells. Further work is in progress on the rougher Wemco cells. This paper describes the evaluation of FrothCam Technology and its subsequent installation.

Jan 1, 2003

Following a decline in direct and indirect employment in the minerals industry between 2000 and 2003, the situation reversed in 2004 and employment rose by 12 per cent. Furthermore, there are forecasts of continuing employment growth in the minerals industry in the immediate future. For those of us charged with promoting the virtues of a career in the minerals industry this is encouraging news, as it provides us with the evidence to promote the increasing employment opportunities of a healthy and vibrant industry. However, for many others û particularly the employers in this industry û the news is not so rosy. The jobs are there, and in increasing numbers, but the workers arenÆt! Employers right across the industry are finding it increasingly difficult to fill vacancies with suitably qualified and skilled employees and the competition is becoming fiercer. In the minerals and energy sector, questions are being asked and solutions sought on the industryÆs ability to attract and retain a skilled workforce. From many quarters û industry, government and the education sector, calls for urgent action are becoming louder. The reasons for this are well known û the nature of the work, the remote location, perceptions of the industry, an aging workforce, the gender imbalance, the shrinking demographic of school leavers. It is the latter I wish to focus on û the Generation Y demographic û those who have recently left school, those who are in higher education or have recently entered the workforce, or those who are still at secondary school. These young people are the next cohort of potential employees for the industry. But our need for them appears to be greater that their perceived need for us! How do we engage them so they are informed about the industry? How do we inform and advise them so they are prepared to consider further education and training in disciplines and skill areas relating to our industry? How do we guide and motivate them to give it their best shot and work in it û at least for part of their working life? These are fundamental questions that many within the industry have been grappling with for quite some time. Let me share with you some of the strategies that the Minerals Council is implementing to address this issue.

Jan 1, 2005

By A Harburg, A Dendys, G Green

Dugald River Mine (DRM) is located approximately 85 km north-east of Mount Isa, and 65 km northwest of Cloncurry, in the north-west Queensland Minerals Province of Australia. DRM is an underground operation and includes an above ground processing area, a 200 ha tailings facility, two waste rock dumps and associated infrastructure. The mining method is conventional underground longhole open stoping and downhole benching of a lead/zinc deposit within a black slate environment. The deposit is estimated to contain ~53 Mt of zinc and lead, which will be mined over a 30-year period. During operations, waste rock is segregated into either Potentially Acid Forming (PAF) or Non-Acid Forming (NAF) based primarily on the sulfide concentration of the rock. In particular, the NAF waste rock is an asset and is used for various small construction projects during operation; however, its primary use is for rehabilitation work at closure. Since beginning operations in 2017, DRM has generated more NAF than was originally anticipated. Whilst this is an excellent asset to DRM, it did pose a logistical problem of where to store the additional NAF for the life-of-mine and how to manage the run-off. DRM experiences distinct wet and dry seasons with hot conditions and periods of rainfall between November to April, and relatively dry and mild conditions between May to October. Majority of rainfall is received between January and February with an annual average rainfall of 501.1 mm. Short and intense rainfall events are common. DRM’s above ground infrastructure is land-locked between two large ephemeral watercourses, making the significant expansion of any assets challenging from a permitting/regulation and cost perspective. MMG is also a member of the International Council on Mining and Metals (ICMM) and is committed to adapting to a changing climate through operations and closure. Following extensive studies DRM opted to store the additional NAF material into the adjoining NAF Dam and concurrently upgrade a previously minor sediment basin into a highly engineered sediment basin which relies on automatic flocculant dosing to meet the required discharge quality limits. This basin is climate-resilient in that the dosing system can be adjusted to counter high intensity extended rainfall events which produce highly variable inflow water quality. This abstract broadly describes how DRM designed and implemented an engineering innovation to enable the site to meet the changing climatic challenges. The abstract then describes the process to design the sediment basin and how the dosing rate was established and validated. Finally, the abstract comments on the effectiveness of the sediment basin and how it has revolutionised DRM’s approach to water treatment and management; all whilst minimising the disturbance footprint of the operation

Aug 2, 2023

By D Bradshaw, R Dunne, S Farrokhpay

It is well known that clays affect the flotation performance, and many of the refractory gold ores around the world contain clay minerals. Therefore, an ore sample from the Carlin Trend was selected for this study as these ores contain large quantities of clays. The presence of clay minerals in an ore makes it susceptible to a range of variables, such as the solution chemistry determined by pH and the chemistry of the rheology modifiers. The viscosity of the ore slurry was measured as a function of solid concentration and particle size distribution, in addition to using different rheology modifiers and pH regulators. The results were correlated with the ore flotation performance. It was found that various reagents known commonly as dispersants or rheology modifiers have different effects on the ore slurry viscosity. This study revealed that the gold flotation recovery can be improved by changing the pulp rheology.CITATION:Farrokhpay, S, Bradshaw, D and Dunne, R, 2013. Rheological investigation of the flotation performance of a high clay containing gold ore from Carlin Trend, in Proceedings World Gold 2013, pp 333-340 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

Technological advances evolve in different ways; many are the result of years of application of scientific method. i.e. Observation Deduction Hypothesis Proof In the mining industry, better explosives, drill bits or reagents are likely to evolve in this way. The scientific method is suited to the application of conventional management structures. Other advances are simply the result of a "brainstorm", or building a better mousetrap. Such inspiration probably resulted in "Split Set" rock bolts, or the first use of a vacuum cleaner principle for shaft mucking. Individual consultants can apply lateral thinking to generate such inspiration. In gathering material for the presentation of this paper, I sent a.letter to all members of the Mineral Industry Consultants Association asking them to nominate problems in the industry requiring investigation. The answers have been divided into two classifications - contract research underway and identified problems requiring solutions.

Jan 1, 1986

By D Barclay, S Mercer, S Wright

Mine water management is often an afterthought in mine planning processes and can introduce significant risks to projects when studied as a stand alone component at a later stage in the mine design. Incorporation of a mine dewatering and pore pressure dissipation strategy in the early stages of mine planning is imperative in order to minimise constraints on the production schedule, to match designed pit slopes and maximise project value for an open cut mine option such as Olympic Dam. A risk-based mine planning approach was adopted during the project selection phase study whereby water management was introduced into mine planning, scheduling and the development of an operational strategy. Hydrological and hydrogeological studies and outputs were successfully integrated into the various iterations of the mine planning cycle during early selection phase to manage the potential water management risks associated with pit slope depressurisation and access to dry working conditions during rapid advancement of mining phases.An extensive network of vibrating wire piezometer sets and long-term depressurisation testing characterised aquifer conditions and demonstrated that hydraulic connectivity exists within the geological profile due to the presence of structures and resource drill holes which enhance vertical connectivity. This connectivity, along with underdrainage from mining activities contributes up to 100 m of depressurisation in low permeability units.A pit dewatering strategy incorporates the mine planning schedules and accounts for operational constraints as to the location and development of the dewatering wells, storages and pipelines. Numerical modelling generated a range of likely pit inflows and dewatering requirements with the average initial dewatering discharge likely to be 150 L/s and reduce quickly to 50 L/s after five years, depending on the premine schedule.Coupled hydrogeological and geotechnical assessments were also carried out as part of the mine planning cycle and indicate that successful dewatering will go a long way to reduce the pore pressures within key geotechnical units during the rapid mining phase where around 300 m of cover sequence is stripped in five years. However, the residual storage in the primary aquifer and the residual pore pressure in underlying low permeability units will need to be dissipated (in-pit horizontal holes) as the pit floor advances. Pit slope design angles are sensitive to depressurisation and dewatering and up to 70 per cent depressurisation of key geotechnical rock units are required. Whilst an accelerated program of aquifer dewatering supported by lithostatic unloading should drive rapid depressurisation in the lower permeability units, intervention is anticipated in key geotechnical units such as the Tregolana Shale and volcaniclastics. The extent of induced drainage will ultimately depend in part upon the mining rate and geotechnical stability requirements. Practical operability testing addressed the potential for operational constraints to mine depressurisation activities such as congestion and mining schedule development within the pit and identified that depressurisation drilling can be achieved even with reduced access availability. Mine operations and planning groups established design criteria and considered the likely inoperable periods following rainfall events of seven to 14 days to manage the base surge and minimise impact on production. In-pit surface water management options to minimise operational disruptions during and after significant rainfall events were estimated used a stochastic approach.

Jan 1, 2009

By G N. Phillips

No new goldfields have been found in the Witwatersrand Basin for over 60 years, and one consequence of this is a long-term decline in gold production. Exploration throughout this period has been based on the placer model that infers alluvial transport of gold grains and then sedimentary sorting in the basin; however, there is no viable source for so much alluvial gold and no single sedimentary setting that hosts the gold.An alternative genetic model can now provide a quantified explanation for the source of the gold, and it does not rely on alluvial gold processes. The hydrothermal model can easily explain the source of the Witwatersrand gold as being derived from the background gold at parts per billion (ppb) level throughout the Kaapvaal craton of South Africa. This gold is involved in metamorphic processes, available for solution in metamorphic fluids, and hence may be transported whilst dissolved in fluid into the Witwatersrand Basin. The hydrothermal model warrants consideration as it can explain the source of gold, the large alteration halo in the goldfields, the mineralogy, and especially the gold-carbon association.Working on the premise that if one model (placer) is not giving the desired results (discovery of new goldfields), then it may be prudent to consider alternatives. Application of a hydrothermal model to guide exploration would place importance on large and small early structures in and around the Witwatersrand Basin; it would also emphasise the geochemical nature of potential host rocks (especially C and Fe) rather than their sedimentary origin.CITATION:Phillips, G N, 2013. Origin of Witwatersrand Gold - a viable source region and source process for gold, in Proceedings World Gold 2013 , pp 175-180 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

Past arguments advocating reverse circulation sampling against blasthole sampling are reviewed to present the debate under a different light. The advantages and disadvantages of each drilling method are compared, and the choice is presented as an informed trade-off between them.

Mar 1, 2010