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By D Whitworth

The Golden Pig mine has embarked on a diamond drill program design philosophy that increases flexibility of the program by greatly increased drill pattern densities. The use of standard broad pattern diamond drilling at the Golden Pig mine has previously lead to operational inefficiencies and impacted significantly on the costs of the mine. The diamond drill program philosophy and its interaction with mine planning is explained. The case study of the E lode mining as used to internally justify the increased drill densities is detailed.

Jan 1, 2002

A very wide range of technologies are utilised in the mining and processing of ores and a great deal of effort is expended in the development of ænew technologiesÆ to improve mining performance and economics. Traditionally, technology and people have been treated as separate aspects of an operation, when in fact they are inextricably linked. The successful implementation of new technologies is entirely dependent upon the actions, enthusiasm and skills of people, both as individuals and working in groups. This paper discusses the role of technology in mining and how new technologies are implemented by the industry. The paper argues that existing technologies have not been fully or adequately utilised and that effort should be re-focussed on the implementation of technologies that have been taken for granted for many years. The need for greater emphasis to be placed on the management of the human-technology interface is discussed.

Jan 1, 1998

THE question of dealing with the small quantities of copper found in a great many of the purchased ores became a factor of importance when the Sulphide Corporation decided to refine its own lead bullion, as the presence of this impurity has a marked effect on the efficiency of the de-silverizing operations of the Parkes process. Removal of the copper from the base bullion.The copper is removed from the base bullion by drossing, which collects the copper, and at the same time has considerable gold, silver, and lead values. The drassing of the bullion is done in two stages-firstly, at the smelters; and secondly, in thecopper kettles at the refinery. In both cases a "wet" dross is produced, which is subsequently "sweated" in a suitable type of furnace. When "dry" the dross is raked out and stored until enough accumulates to warrant a nUl on dross in the small blastfurnace kept for that purpose. A typical assay of the "dry" dross is as follows...WORKING THE DROSS UP TO LOW-GRADE CU-PB MATTEThe accumulated dross is treated in a small blast furnace with the necessary fiuxes, producing a low-grade Cu-Pb matte and base lead bullion.

Jan 1, 1920

By P Gleeson, J Coombes, P Suresh, T McLennan

The last 20 years have seen a dramatic rise in the use of 3D visualisation and modelling for geological data, but there has been relatively little effort to do the same for the variogram models that underpin the standard estimation algorithms used by the mining industry.For kriging, one of the most used geostatistical estimation methods, specifying a variogram model is a critical part of the modelling process. Experimental variography is the primary method for approximating the theoretical variogram function from the available sample data, and then determining an appropriate variogram model from the approximations.The traditional tools used for experimental variography are limited to looking at subsets of the data and are often presented without reference to geographic space and geology. It can be difficult to know what input data is being used for a particular experimental variogram, and whether there is enough support in the experimental variograms to propose an appropriate model.To overcome these limitations, an innovative approach called situational variography has been proposed that visualises variograms in 3D alongside contextual geological and geometric data. Presenting variograms in this manner aids understanding of how the spatial variance relates to the underlying data.A 3D extension of the 2D radial variogram maps will be investigated which allows for dynamic exploration of the full experimental variogram cloud. These 3D experimental variograms are much easier to visualise situationally.A workflow for situational variography will be outlined and the advantages of the situational approach will be illustrated using a porphyry copper deposit.CITATION:Gleeson, P, McLennan, T, Suresh, P and Coombes, J, 2017. Situational 3D variography – determining the variogram in the context of geology, in Proceedings Tenth International Mining Geology Conference 2017, pp 191–198 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By R Barritt, P Scott

Across the globe, it is a common scenario that tailings storage facilities (TSFs) are being decommissioned; however, their subsequent impact on the local environment and landscape can often be overlooked during the mine planning process. In addition, the requirement of a cover system for a facilities closure may not be a priority until the latter stages of the mine/mill operation when potential cover materials may have been utilised elsewhere or, worse, buried. Developing a conceptual design and closure plan for a TSF early in a mining venture is fundamental to its success once operations have ceased. If a cover system is a planned component for rehabilitation of a TSF, it is vital that its design is appropriate to the facility and any local site constraints, such as climate and cover system material availability. It is also strongly recommended that various cover system options are physically trialled at the site by using performance-monitoring instrumentation. Through this process, an informed decision can be made regarding the most appropriate cover system design to meet any regulatory and stakeholder closure objectives and criteria specific to the site in question; however, in order for the cover system’s performance to be determined through on-site trials, it is essential that an appropriate instrumentation design is utilised. Often, little attention is paid to the data that is being obtained, and its importance may only become apparent after several years of monitoring at an expense to the venture. This should not be the case. Many sites have used an appropriate initial planning stage to understand what is required for the successful closure of a TSF, how it can be achieved and how monitoring data can be utilised to prove, or otherwise, that a cover system design will be a success.CITATION:Barritt, R and Scott, P, 2015. Cover system performance monitoring for tailings – are we doing it correctly?, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 283–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

Most mining operations have been happy to live in blissful ignorance of what their equipment is really capable of. Shareholders have been shown increasing tonnes output per employee (due to rationalising employee numbers). It is now known that the best practice for large mining trucks is 52 per cent higher than average or best practice for excavators is 41 per cent higher than average, or 38 per cent in shovels or 35 per cent with draglines, etc. The data is available. The bell curve of performance is flat. Substantial underperformance is rife. If you are working in or supplying equipment or services to one of the majority of operating mines that donÆt achieve best practice surely you want to know why. Or maybe you donÆt? For many mining people this sort of knowledge could be dangerous to their career so keeping the MD or CEO in the dark is a good option. Many suppliers donÆt want the performance of their equipment benchmarked? Mining consultants donÆt have the data so they are happy to keep guessing. Unfortunately, many Business Improvement or Business Excellence projects are about ticking the participantÆs æcareer boxesÆ. The first step to capacity utilisation is knowing what the capacity is. Even then people and culture will get in the way. People are the biggest hurdle to capacity utilisation. This paper will discuss what the mine of the future (and today) will need to do to utilise the productive capacity of its assets. It is not just benchmarking. It is not just automation. It is not just technology. It is about engaging those people who impact on equipment performance; right from the operator up to the Mine Manager. Doing it better involves a process to facilitate change and a culture which says it is OK to try even if you are wrong.

Jan 1, 2009

Environmental leaching methods such as the toxicity characteristic leaching procedure (TCLP) test or the ASLP test are used to assess wastes including mining and mineral processing by-products. These tests were initially designed as regulatory tests simulating conditions in a co-disposal municipal landfill waste facility and do not allow leaching performance to be predicted in site specific scenarios. Further, the assumptions underlying these tests tend to define worst-case scenario leaching conditions for by-products from the mineral industry disposed of outside a co-disposal scenario.   Recently some characterisation leaching test methods have been issued as ISO/TS standards (ISO/TS 21268-3:2007 and ISO/TS 21268-4:2007) that aim to define the leaching performance of soil type wastes and to predict the leaching performance of these wastes over long time frames. In this preliminary work these standards are trialled for by-products from the mineral industry and the quality of information that can be obtained from them compared to TCLP/ASLP tests.   Where clear comparisons were possible, the TCLP/ASLP tests were typically found to extract a similar, or often greater, amount of component than (i) tests conducted at the same pH but without the acetate buffer or (ii) for test conditions aimed at simulating long-term leaching in an eluate defined by the waste type. While further work is required, the preliminary results indicated that the tests may provide reliable long-term estimates of leaching performance of wastes in soil types of variable pH and provide a suitable basis for long-term planning for optimal waste handling, treatment or even re-use.

Jun 1, 2010

By H Esterhuizen

The Ernest Henry Mine (EHM) in Queensland, Australia is a Sub-level Caving operation that started production below the previously mined open pit at a depth of 535m. Current Production mining has progressed to a depth of 730m, with planned production mining to extend down to at least 1000m below surface. The inclined nature and geometry of the orebody combined with geological structures provides for challenging mining conditions. Over several years, Ernest Henry Mine has introduced measures to improve outcomes based on observations, monitoring and data analysis. As mining progresses deeper, EHM will continue to proactively take steps to ensure future outcomes are anticipated and mining can continue safely and uninterrupted. The focus of this paper is on the changes in seismic- and stress-driven behaviour of the rockmass experienced at EHM, the ground control measures implemented, and the anticipated future conditions and controls required. CITATION:Esterhuizen, H, 2018. The evolution of seismicity and ground control measures at Ernest Henry Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 20–41 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By E Westthorp, J Phillips

The detection of ethylene in mined-out ‘goaf’ areas of underground coalmines is an industry standard indicator of accelerated oxidation where the coal temperature has exceeded 100°C. If uncontrolled, this naturally occurring process can lead to spontaneous combustion and catastrophic mine explosions, such as the Moura No 2 mine explosion. Spontaneous combustion trigger action response plans (TARPs) typically use the detection of ethylene as a trigger for definite change requiring immediate reaction, which can include the withdrawal of coalmine workers.Following the completion of sealing of longwall goaves at Crinum North Mine, ethylene was often detected in trace quantities. These trace quantities were below 1 ppm and detected via the bag sampling regime, with the use of a gas chromatograph. Any ethylene detected in these instances was not associated with increased quantities of carbon monoxide to conclusively indicate a heating within the sealed area.Ethylene was only detected in a newly sealed goaf and would not remain present for a period following the sealing. As part of the longwall recovery process, the predominant roof support mechanism during the recovery was the use of timber cribs. It was decided to investigate the possibility of this timber generating ethylene.Preliminary tests were completed by placing timber specimens from several species of Australian native hardwoods in gas bags in air. Over time, some of the samples showed significant levels of ethylene within the bags.CITATION:Westthorp, E and Phillips, J, 2017. Findings from preliminary testing to determine alternative sources of ethylene within sealed areas of underground coalmines, in Proceedings Australian Mine Vent Conference 2017, pp 203–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

The Department of Mineral Resources is the lead agency in mine site environment management and control in New South Wales. The Department introduced a Mining, Rehabilitation and Environmental Management Plan (MREMP) process several years ago in order to integrate the activities of other government agencies who may have a material interest at the mine site. The MREMP process has resulted in a spirit of trust and co-operation between agencies and between agencies and mining companies. The spirit of co-operation has been reflected in greater public confidence that mining is environmentally responsible.

Jan 1, 1995

The Small Pebble Process for Reducing Ball and Power Consumption in Secondary Grinding Ball mills are used widely for secondary grinding. A mixture of ball sizes can be used to optimise grinding efficiency, but the use of balls smaller than about 30 mm in diameter is not normally viable, particularly when alloy steel is required. Preliminary testing of the grinding efficiency of various combinations of 40 mm steel balls and crushed stone in the size range 7 to 25 mm was carried out in a 300 mm diameter mill, which has accurate power measurement.The primary interest was to assess the potential benefit of adding small pebbles (from a primary circuit crusher or mill) to a secondary ball mill, to reduce ball consumption and to improve grinding efficiency. The optimum proportion of pebbles was found to be about 25 per cent by volume. This mixture produced about the same amount of fines as balls alone, but with lower power consumption, due to the lower density of the pebbles. The net result was a 12 per cent saving in power and a 25 per cent saving in ball consumption. The production of fines was partly due to pebble wear. The use of portions of 15 mm balls, (ceramic and steel), was also tested for comparison. A few batch pilot-scale tests were conducted in a 1.2 m diameter, 0.31 m long mill to test the viability of the pebbles at a larger scale. The pilot-scale tests confirmed the reduction in power and that the rate of production of fines was the same as that obtained with balls. The same residence time was used and this implies that pebbles can be added to an existing full-scale ball mill, with no loss in capacity. Samples of secondary mill feed and pebbles were obtained from a copper mine and the steady-state consumption of pebbles was determined by locked-cycle laboratory-scale tests. These tests demonstrated that mill power could be reduced by up 13 per cent and that the consumption of 40 mm balls could be reduced by up to 38 per cent, while maintaining the same throughput and product size. The rate of pebble addition was about 4 per cent of the primary circuit feed rate. Application has been made for patent protection.

Sep 13, 2010

Optimisation of the Advanced Automation System at Inmet Mining's PyhSsalmi Mine, Finland

Sep 13, 2010

THE choice of a pumping plant for the drainage of a mine is a matter of such importance that it is obvious that in a short paper it is impossible to go fully into the reasons governing the adoption of any particular type. The author, therefore, proposes to briefly discuss the methods.in vogue, and, as far as possible, to point out the advantages and disadvantages of the numerous systems. The probiem is of extreme importance to the mining engineer, and it appears that in the past sufficient thought has not been given to this branch, as shown by the numerous failures which are encountered.When water is met with in large quantities, the development of the mine depends upon the pumping plant to such a great extent that the most careful consideration should be given before deciding on any particular scheme for drainage. The pumpingplant in a mine should be looked. upon in the light of an insurance policy, and should be treated as such, care being taken that the premium is as low as possibl~, and to ensure this it is necessary that the most efficient plant be secured. Local conditions play such an important part ill the design of a plant that no hard and fast rules can be laid down. When the amount of water to be handled is small, and there is no possibility of any increase...

Jan 1, 1912

By P Hatherly, A Melkumyan, D Wyman

Chemical species distributions in rock sequences can be modelled using Gaussian processes (GPs) to predict the weight percentage between known data points. This method can be improved by dividing the modelled area into regions of different mineralogy. In the context of many iron ore deposits, marker shales give the initial guidance of where these regions may lie. These shales give rise to distinctive peaks in the natural gamma downhole logs, which are conventionally identified by hand. A GP method has been developed to automate this task.Once the appropriate boundary has been located on the basis of shale occurrences, chemical assays from exploration drill holes are used to find the exact boundaries of interest. These boundaries divide the drill hole stratigraphy into regions of different mineralogy, each of which display their own distinct correlations between the main elements and oxides (Fe, SiO2 and Al2O3). Iron ore shows a negative correlation between Fe and Al2O3, but in banded iron formation (BIF) there is a positive correlation between these species. Similarly, SiO2 and Al2O3 have a positive correlation in the shales and ore but a negative correlation in the BIF. Correlations obtained within ore-, BIF- and shale-dominated regions are therefore better than those obtained using the entire log and can be used to improve the results obtained when modelling.

Sep 26, 2011

Rehabilitation has been very effective in the short to medium term in providing a cost effective and reliable means of containing the side effects of land disturbance. However, there is still insufficient data to critically evaluate the sucess of rehabilitation in the long term. There is an urgent need to develop objective criteria to monitor the sucess of rehabilitation. The aim of rehabilitation in Australia has traditionally been to return disturbed land to natural vegetation compatible with the surrounding area. This objective has often been accepted instinctively without adequately addressing alternatives.

Jan 1, 1992

By D La Rosa, D Bennett

"Exploration drill core provides for a number of standard measurements essential for determining the viability of a new mine or the extension of an existing one. Rock lithology and alteration can be visually determined and grade measured from the half core. Geotechnical parameters such as rock strength and structure can also be measured. Using suitable proxies, these metrics can then be used to estimate run-of-mine (ROM) particle size. In combination with comminution test results, these can subsequently be used to design comminution circuit configurations and estimate their performance.The Frieda River Project drill core for the large Horse-Ivaal-Trukai copper-gold porphyry deposit was unusual due to a late stage gypsum-anhydrite stockwork event that overprinted much of the deposit. Above the base of the oxidised zone, which closely matches the water table, gypsum and anhydrite has been leached out, effectively removing the glue holding the rock mass together. As a result, much of the rock above this gypsum-anhydrite surface is fragmented and gravel-like in texture, while the material below this horizon is typically uniform and competent.Large volumes of the orebody above the gypsum-anhydrite surface are expected to need minimal or no blasting for efficient excavation. In addition, the fragmented nature of much of the material was expected to reduce comminution specific energy as it already appears as though it has been crushed. While this was expected to have positive impacts to the operation, the lack of standard geological logging methods available to accurately define the degree of in situ fragmentation led to difficulty in gaining certainty over the ROM product and grinding circuit feed size distributions.Using the extensive library of core photos for the project, a novel method using image analysis techniques to take both the intact core and gravel into account to predict ROM fragmentation was developed. In addition, existing point load test data was used to infer the strength of the rock and its impact on the blasting, crushing and grinding processes. The novel approach allowed development of ROM size distribution data and improved certainty in the results of comminution circuit designs.This paper describes the methodology undertaken in detail, and discusses the results obtained.CITATION:Bennett, D and La Rosa, D, 2016. The Frieda River Project – a Novel Approach to Analysing Exploration Drill Core: How Broken is Broken?, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 65–76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

The early records of hydraulic elevator and bucket ladder dredging in the Clutha River system indicate the success of that era of alluvial gold mining in Otago. This paper briefly reviews parameters of depth and gold grade for alluvial operations. The application of dragline technology is proposed for the economic removal of overburden to target the deeper alluvial gold areas which remain in the Otago region.

Jan 1, 1992

By Liu Y

Mathematical modelling of scrubbers in development and longwall operations in underground mines produces useful results. Mathematical modelling on the mounting of scrubbers on longwall supports shows that the number of scrubbers and the air quantity through the scrubber are the two important parameters. Increase in both these parameters results in decrease in dust levels at the tail gate. The critical factors are scrubber efficiency and the ratio of the air through the scrubber/total air quantity.Results of parametric studies conducted to establish factors which have dominant influence on the effectiveness of the scrubbers on dust levels and high gas build-up in the scrubber show that for use of scrubbers in development headings, the order of importance of parameters in relation to dust concentration in the scrubber area is: scrubber efficiency, rate of production, specific dust make/tonne, leakage factor, intake dust concentration, recirculation factor and air quantity through the scrubber.The equations developed for mathematical analysis and the detailed results of modelling provide useful data on recirculation of emitted gas in the use ofscrubbers for dust control.

Jan 1, 1995

Gold mineralisation at Wapolu lies within an exposed arcuate zone at the decollement contact between a basement dome of high grade metamorphics and an overlying ophiolite sequence. This contact was originally a thrust fault which has since become a decollement zone for gravity sliding in association with basement doming. Hydrothermal models for the gold mineralisation postulate an epithermal system in which fluids were channelled up the decollement with boiling of those fluids causing hydrothermal brecciation and subsequent gold deposition. The alteration assemblages, fluid inclusion data and geochemistry indicate that the upper levels of the system are exposed.

Jan 1, 1987

By J Kok

"In some underground mines it has been observed that the primary focus during feasibility studies is to determine the best way to mine the defined orebody. Some studies have been conducted without sufficient consideration of the ventilation and cooling requirements or the risk from exposure to associated airborne pollutants caused by the mining operations.Following the hierarchy of control to manage risk, numerous problems of the ventilation systems in some underground mines could have been avoided if sufficient consideration was given to the ventilation requirements to manage heat, airborne pollutants and leakage during the feasibility study phase. If the constraints and hazards were well defined and understood at the time of the study, efforts could have been made to eliminate or substitute the hazards to decrease the risk. Some of these problems include but are not limited to: primary fan locations heat loads diesel exhaust ventilation design based on the production requirement fire/emergency response strategies.This paper highlights areas in the ventilation discipline that are sometimes overlooked during feasibility studies. It will also highlight the importance of the Ventilation Specialist during these studies. Experience and knowledge of best ventilation practices must be applied in feasibility studies.As a result of adequate consideration to all ventilation aspects in the feasibility study phase, risks will become lower in terms of health, safety, production loss and equipment downtime caused by heat.CITATION:Kok, J, 2014. Feasibility studies – what should be considered in terms of ventilation, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 197–204 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014