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Last September, when I was asked to prepare this paper, I was told the subject was "mining," a broad subject indeed! Rather than choose one of the many important technical and economic details which characterize mining today, I turned to a subject which fas- cinates me: mining's image. If we are to survive and prosper into the twenty-first century, and if industry and society are to continue enjoying the material benefits which flow from mining, we must address the melancholy fact that the general public at best does not understand mining, and at worst does not believe it is needed or deserves to continue. While my point of view is largely that of an American mining executive, I would hasten to point out that Homestake has participated in Australian mining for over three decades, and our subsidiary, Homestake Gold of Australia Limited, is now a major producer in this "lucky country." Does society need a viable minerals and metals industry? The answer is obviously "yes," so the challenge is to change some minds: not just those of the amorphous "public," but on a focussed basis targeting journalists, educators, TV commentators, politicians and opinion makers of all stripes (I thought of using "rifle shot" instead of focussed but thought that might be misconstrued). Along the way we miners must also look deeply into ourselves, our attitudes towards the society in which we function, and our willing- ness to change as well as to seek change in others. How did we become such bad guys? More than a century ago mining was not just accepted, it was even romanticised. In America, we had altered the time-honored concept of "Crown" lands into public lands made easily available to settlers pushing back the frontier. Miners even preceded the farmers and stockmen in what was perceived as nation-building, although by the 1890s there was a growing interest in conservation, especially the protection and management of forests and national parks. Even though emphasis was shifting toward government stewardship and away from trans- fer of public lands to private ownership, homesteading and mining were clearly recognised as valid uses requiring not just access, but security of tenure. Indeed, conservation as it was then understood implied management of the public domain as well as its protection. Initially this was no great problem to the U.S. mining industry, but as the nation grew and competing land uses became more important, conflicts began to appear, first over water rights and later over air quality and destructive mining practices. But these were local disputes rather than national issues, and two World Wars, the Great Depression and post-war reconstruction lulled our industry into thinking that nothing had really changed. After the storm began to break in the 1960s, the mining industry found itself confronted by a growing maze of complex and costly laws and regulations. It took us longer than it should have to realise that, in facing this challenge, we seemed to have lost the understanding and support of many of our legislators and a majority of the general public. For over 20 years now, since the first Earth Day in 1970, the U.S. Mining

Jan 1, 1991

Arrow Energy NL has been operating a number of coal seam gas wells in the Darling Downs region of Queensland. At the time of writing this paper, the region is enduring an extended drought period. The local aquifers are depleting and have not been significantly recharged in over a decade. The local communities (both rural and townships) are struggling to obtain water. Currently, coal seam gas (CSG) operators (under licence) draw water from the coal seams as part of the gas production process and the majority of operators choose to evaporate this water, as it is characteristically brackish to saline in quality and as such must be contained. Although the water produced from one CSG operator is not sufficient to drought-proof the greater area of the Darling Downs, there is potential to supply smaller local areas and contribute to the sustainability of these communities. This paper outlines the work completed by Arrow and its local community partners on the Darling Downs to date, and discusses the application of the produced formation water for:stock watering in feedlots, as a feedstock for coal washing, as a potable water supply for Dalby, as an agricultural water supply for cotton farming, and use as a medium for growing salt-water fin fish.

Jan 1, 2006

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

Sheaves are a critical safety component in a winding system and are expected to survive such extreme loading events as rope break. Sheave designs have often been developed and evolved empirically, consequently many existing sheaves are not necessarily subjected to the detailed analyses that are possible using todayÆs design tools. The design philosophy for sheaves is that the rope should be the weakest link in the system so that associated equipment can function safely for any load up to rope break. A number of failure mechanisms must be considered, but buckling is often prominent. During the course of investigating the feasibility of upgrading the hoisting capacity of a winding system, the capacity of all critical components was reviewed. The sheaves in the system were found to have insufficient spoke buckling capacity for the specified rope. A proposal to increase the spoke buckling capacity by connecting spokes together using a simple tie arrangement was evaluated and found ineffective. An alternative tie arrangement concept was developed and evaluated and shown to be adequate. This paper describes the finite element model, analysis approach and results for the original sheave and the two modifications. The contribution of the sheave rim to the total buckling capacity is evaluated. Some practical issues for spoke tie modifications are discussed.

Jan 1, 2005

By D Pearce

The 15-year long debate between the industry, Government and Aboriginal people about the rights and wrongs of Land Rights, the right of Aboriginal people to control development on their land and the relationship between the parties, has been long and often bitter. It has so far been a war of words and often the truth has been the first casualty. This paper looks at the debate and presents the perspective of Aboriginal people, as well as looking at how the industry and Aboriginal people can work together for everyone's benefit. It addresses such matters as: ò why Aboriginal people believe they have the right to control development on their land; ò the perception that Aboriginal people are anti-development; ò the perception that Aboriginal land is 'locked-up'; and ò how companies can negotiate with Aboriginal people.

Jan 1, 1994

By J Webb

"It is vitally important in projects where the cut-off grade is low that there is no contamination during the sampling and sample preparation process, both in the ore and the waste zones. Failure to identify contamination could have devastating financial consequences for a project. The use of a variety of blank types is essential for ensuring that contamination is identified and eliminated at every stage of the sampling and sample preparation process. This paper examines an instance where an effective assay quality assurance and quality control (QA/QC) program was able to identify and eliminate a source of significant multi-element contamination in the prefeasibility stages of an open pit project. This examination includes the: evidence for contamination findings of the investigation process of resolving the problem and correcting the data evidence for both addition of metal and dilution through contamination potential impact on the project had this issue not been dealt with. It was through the use of a combination of blank types that the QA/QC process at Mount Isa Mines (MIM) identified a contamination issue at the first crushing phase of sample preparation. Identification of the contamination allowed MIM to stop assaying activities and work with the laboratory to correct the problem. The sampling program could then be continued with no further doubts about the sample preparation process. Contaminated samples were resampled from retained core. With the continuous monitoring provided by the blanks program, it was possible to ensure that only clean results went into the resource modelling data set. CITATION:Webb, J, 2014. When nothing is what you need – the importance of using blanks at all stages of sample preparation, in Proceedings Sampling 2014 , pp 49–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 29, 2014

The tangible effects of leakage are presented graphically, and a technique for quantifying the leakage characteristics of a ventilation column using the æSolveÆ capabilities of a common spreadsheet is demonstrated. A case study of a working decline in Western Australia is used to demonstrate the potential for more realistic design of development ventilating systems, and for more cost effective management of the condition of the duct.

Jan 1, 2002

By S J. Henderson

Pumped co-disposal of coal processing waste was promoted in the 1990-2000s as a low-cost highperformance alternative to tailings dams. In particular it would avoid high up-front capital for rejects trucks and dam embankments, and would produce a combined waste deposit with better geotechnical properties than either coarse rejects or tailings. Overall, the promise was not delivered; in particular, upon discharge the waste segregated by size, and operators responded by moving the coarser waste to contain the finer waste. In consequence, not only did design analysis lag behind construction, but some of the initial expectations persisted with the result that analyses did not fully represent what was occurring on the ground. After more than twenty years inspecting, designing and tending Co-Disposal Areas (CDAs), it is apparent that they are essentially upstream constructed tailings dams with some more favourable aspects but also a few unique quirks. Although waste management technology has moved on somewhat, the high cost of changing CHPP waste circuits means that most mines with pumped codisposal will continue to discharge mixed waste slurry into CDAs. It is therefore worthwhile to share some lessons in the hope of promoting sounder design, operation and rehabilitation. These include: • Discharged waste does not form a homogeneous wholly competent deposit but instead comprises materials ranging from sandy gravel to silty clay with the distribution determined by movement of the discharge and decant structures; • CDAs circulate and contain a lot of water; • As a result of the first two points, some areas of the CDA comprise saturated fine waste that is no different from tailings and, like tailings, often behaves in an undrained manner; • Seepage is inevitable and desirable because strength improves as water is removed. However, stability is strongly impacted by pore pressures and in design these need to be rationally rather than optimistically considered; • As CDAs are built to about 40m or higher, strength-deformation characteristics of the foundation become more important; • Even if geomechanically stable, CDAs will need covers to prevent salts and acids from reaching the surface; and • Erosional stability of the cover material(s) will probably dictate maximum slopes for rehabilitation.

Jul 1, 2021

The technology of coal preparation, while based on similar processes to those in common useage in the 1950s, has improved significantly over the past 15 years primarily due to advances in process control. This technology at least offers the potential for most coal preparation unit operations to be optimised to a considerable degree. However, to maximise the overall yield of an operation from pit to port, factors often outside of the control of the preparation plant operator have a dominant effect. Specific factors include an in depth knowledge of the feed characteristics of the various sources of coal, the detailed mine scheduling to provide an appropriate blend to the plant, and the interim handling and stockpiling processes between the mine face and the customer.This paper summarises the criteria for optimising the yield for a variety of mining, processing and stockpiling options, based on the principle of operating at constant incremental ash. Pragmatic operating assumptions such as extension of the principle to operating at a constant density for gravity operations will be discussed. A means of optimising the compromise between maintaining specification product ash to the customer and maximising yield by always washing at constant incremental ash, without the benefit of a homogenised feed, will also be Presented.

Jan 1, 1992

By G B. French

Post a serious heating event underground, and at the direction of the State Mining Safety Authority, a mining company needed to demonstrate the use of cutting-edge technology to mitigate future events. Yokogawa were contracted to provide a turnkey solution to help the mine achieve this objective. The solution was to use a fibre optic-based Heat Detector that will allow entry into and around the mine considering the potential volatility of the environment, also the need to redeploy as mining activities moved underground and more boreholes are added. Industrial strength fibre optic cable and a robust connector system was chosen to achieve this goal and give the customer the ability to send cable down boreholes of up to +1 km and continuously monitor the temperature ofunderground roadways. Being able to re-deploy the cables into different boreholes and link borehole temperature measurements gave insight into all areas on the mine. The machines deployed on-site were the Yokogawa DTSX1 heat detector incorporating the Ramen Backscatter principle. Being of a robust construction and a low power consumption device, it was easily included into the portable monitoring trailers designed by the customer and built locally.

Oct 12, 2022

By E Jamieson

For a number of years, Alcoa World Alumina Australia (Alcoa) has been investigating opportunities to produce economically viable products from bauxite residues. Three of these potential products are described here, being Red Sand, ALKALOAM« and REDLIMETM.Red Sand has a nominal particle size of +100 micron and is physically little different to crushed bauxite from which it is derived. In AlcoaÆs Western Australian refineries, Red Sand constitutes up to half of the residue going to impoundment areas. Initial testing indicates that this sand could be processed to provide an acceptable general landfill material, a construction back fill or a material suitable for road base construction. ALKALOAM« is the fine-grained residue often referred to as red mud. A great deal of work has been done to show the benefits of adding this material to sandy soils, which are common in coastal regions of WA. ALKALOAM« has properties that can elevate the pH of the acidic soils and also retain phosphorous, reducing overall fertiliser use and protecting sensitive waterways. REDLIMETM is a by-product of the refining process. This material has a high acid neutralising value. REDLIMETM could be more effective at pH control than most available products because of the fine particle size and sodium carbonate that remains with the product.

Jan 1, 2004

By A C. Robertson

Studies by Tennent, Isokangas Pty Ltd (TIP) have indicated that underground quarrying of backfill may be a cost competitive option for providing backfill for specialised situations in underground mining. Situations where suitable bulk fill material may not be available on the surface, and where the total cost of setting up a fill distribution system are prohibitive, could favour the mining of fill material underground adjacent to the stopes being mined. Considerations include environmental impact, scheduling, surface constraints and total costs. The examples quoted in this paper, and the case studies are based on the authorsÆ personal observations and experience.

Jan 1, 1998

By S B. Sheldon

Wall control programs tend to be expensive and consequently require financial justification in order to get approval for the expenditure required. The difficulty faced in getting this approval is that the outcomes of a wall control program are all subjective – a prediction of wall stability and what the wall would do with and without the program. Determining a net benefit is difficult and often justification of a wall control program is based on gut feel, history and a good selling campaign to build a perceived need.This paper outlines a simple solution to this problem by applying risk management principles to wall control. The process is to identify the risks to the operation associated with current wall conditions and then build a risk database for different potential scenarios for each risk. A financial impact is assigned to each risk scenario to complete the database. A consequence and likelihood analysis of each of the risks is undertaken and a formula applied to estimate the projected cost to the operation for the current risk profile. The process is repeated for the predicted wall control conditions after the application of the wall control program. A successful wall control program will reduce an operation’s risk profile so this projected cost should be less than that calculated for the current scenario. The difference in the two projected costs is the value that the wall control program has produced and this value can be used to determine the net financial benefit potential for the wall control program.This methodology can also be applied to other improvement programs that focus on risk reduction such as vibration control.

Nov 8, 2011

By Toussaint LF

A brief history of the mineral sands industry is given from a radiation protection standpoint, with gamma radiation and inhalation of radioactive dust being identified as the main sources of radiation exposure of persons working in the plants. The principal sources of gamma radiation exposure are identified and the history of early bagging methods is discussed. The concept of ALARA is introduced and the impact of the "bulka bags" (and more effective monazite storage facilities) are detailed as illustrative examples of dose minimization, together with the requirements for the transport of monazite. The dose from radiation received from inhaled dust is dependent on a number of parameters of the dust, some of which are not well known. ICRP 30 (1978) makes recommendations relating to the intake of radionuclides by workers. These recommendations are discussed with respect to the inhalation of dust containing thorium. The possible pathways of radioactive material throughout the body are also described. The effect of having parameters that differ from ICRP 30 is discussed and suggestions are made relating to measurements that can be carried out to more accurately determine these parameters. Since in some instances the exposures to dust yield personal doses which may exceed the annual ICRP 30 based limits, it is necessary to define more accurately parameters of the dust so as to determine more accurately personal Doses.

Jan 1, 1986

It is hypothesised that increasing the number of loading passes will produce a reduced range of truck payload outcomes compared with four-pass loading. The paper provides analysis to support this hypothesis. It is shown that, hypothetically, loading trucks with five or more passes will result in reduced tendency for overloading and reduced confidence interval for truck payloads that increase the confidence level of containing high end payloads within safe and commercially acceptable limits. Furthermore, increased number of passes provides for more precise bucket load spotting and so improves distribution of payloads within truck bodies. Truck-loading issues examined by the paper include: Improvement in life of driveline components and tyres. Generally tyre costs are relatively moderate; but tyres tend to become an increasingly sensitive performance/cost component as truck scale increases; Reduction of site severity fects flowing on to suspensions, truck frames and structural components generally with potential for reduced long-term repair costs; Less physical body damage due to smaller load increments; Reduced risk of non-compliance with payload limitations for safe braking standards; Increase in loading cycle times tend to increase with scale of loading machinery within the limits of a specific type of equipment (ie rope shovels or hydraulic shovels). Production increase with increased bucket capacity is, to a degree, offset by slower loading cycle times. This is particularly pronounced with front-end loaders but tends to be less noticeable with hydraulic excavators/shovels and electric rope shovels. Decrease in loading time, as a proportion of total truck-cycle time as open pits deepen and dump reaches increase. The production and cost benefits of four-pass loading tend to diminish as truck cycle times increase. The paper also discusses the implications for loading-equipment philosophy to satisfy the future needs of the industry. Cost benefits from upscaling tend to diminish as truck scale increases, so increasing management diligence and close monitoring are required to ensure that expected outcomes are realised. These truck-loading issues have been researched to assess the benefits positive or negative) of four-pass loading in practical scenarios. An attempt is made to determine whether four-pass loading is a æmust-haveÆ or merely a æmythÆ.

Jan 1, 2003

By X Ma

Kaolinite is of very fine particle size in nature and thus its dispersion plays a key role in the successful removal of kaolinite in iron ore flotation and selective flocculation processes. As the most widely used dispersant in the world, sodium silicate has been used as a standard dispersant for kaolinite in the iron ore industry. However, the actual effect of sodium silicate on the colloid stability of kaolinite particles and its dispersion mechanism remain unknown in the literature. In this work, the dispersion effect and dispersion mechanisms of some common inorganic and organic dispersants, including sodium silicate, polyphosphate and a low molecular weight polyacrylic acid, on kaolinite particles were systematically investigated through electrophoretic mobility and colloidal stability studies over a wide pH range. It was found that sodium silicate-kaolinite interactions only take place in the neutral and acidic pH range, while polyacrylic acid and polyphosphate interact with kaolinite from pH 3 to 10.5. Consequently, sodium silicate only disperses kaolinite at neutral and acidic pH. In contrast, polyacrylic acid and polyphosphate disperse kaolinite from pH 3 to 10.5, with strong dispersion effect observed at neutral and acidic pH. In the iron ore industry, selective fl occulation and reverse cationic fl otation, the most widely used flotation route, are both conducted at pH 10 to 10.5. The results of the present study show that, at such high pH, polyacrylic acid and polyphosphate are more effective dispersants of kaolinite, in comparison with sodium silicate.

Jul 11, 2011

By J G. Shellnutt, Y Iizuka, T W-Y Hsia, T-C Liu

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The formation of magmatic oxide ore deposits hosted in chemically-evolved layered gabbroic intrusions is attributed to a variety of petrological processes, but there is little to no consensus on the general applicability of each model. Complicating the matter further is that many layered gabbroic intrusions are spatially and temporally associated with alkaline A-type granites, suggesting that there is a petrogenetic relationship between the two types of chemically different rocks. Our experimental results show that petrological modelling using a starting composition of high-Ti basalt from the Emeishan large igneous province can produce evolved silicic liquids that resemble the compositions of microgranular enclaves from the syenitic unit of the bimodal, oxide ore-bearing Baima igneous complex. The experimental results confirm that bimodal gabbro-granitoid complexes can form from a common parental magma and that early crystallisation of Ti-rich magnetite can explain the formation of the oxide ore deposits in the lower parts of the layered gabbroic intrusions. We conclude that crystallisation of a typical high-Ti basaltic parental magma can produce world-class giant magmatic oxide ore deposits and that the occurrence of some alkaline granites may be an indicator of their presence.CITATION:Shellnutt, J G, Hsia, T W-Y, Liu, T-C and Iizuka, Y, 2015. Cogenetic formation of the peralkaline syenite and oxide ore-bearing layered gabbroic intrusion of the Baima igneous complex, Emeishan large igneous province, south-west China , in Proceedings PACRIM 2015 Congress, pp 317–324 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By J Rutter, S Dunham

Technological advances in sensor and material handling technology has enabled a step change in mine operations performance. Sensors capable of monitoring the grade of broken rock mass can be mounted on shovels, truck loading units or conveyors allowing highly precise ore/waste decisions to be made on small parcels of rock, increasing selectivity. This increased selectivity has the potential to remove sub-economic material from the product stream prior to incurring ore treatment costs. Bulk ore sorting is capable of intervening at <10t “pods” on Run Of Mine conveyors, or alternatively at per bucket loading (5-100t) or truck scale (30-350t) parcels of ore. This Grade Engineering technique being developed by CRCORE (Rutter, 2017) can improve mill feed grade, remove deleterious materials and ensure that the high capital intensity ore treatment facility is presented with the best ore feed strategy. While this technology can improve mine economics, estimating the performance of a bulk ore sorting system is challenging. Traditional resource estimation practices such as Ordinary Kriging and Inverse distance weighting (IDW) are based on weighted averages, a process that smooths the grade profile, reducing modelled variance and dispersion. Its purpose is to generate a globally unbiased result but is less suited to generating a model of adequate granularity to enable confidence in local grade heterogeneity. This is an essential component for bulk ore sorting success. Estimating ore sorting performance requires knowledge of the grade-tonnage curve at the scale of the sensor diversion unit (SDU). Evaluation based on an estimator that smooths the SDU distribution will not correctly predict ore/waste separation or economic performance. Alternatives to traditional linear geostatistics have been tested on a variety of mineralisation styles. Additionally, a number of heterogeneity metrics have been developed to assist with evaluation and assessment. The difference between estimation for grade (metal) and modelling for traditional mining block models, versus methods used for predicting heterogeneity and variability are explored.

Nov 10, 2020

By M J. Pejovic, S BoÜevski, I Miljanovic, M Hudej, A Milutinovic, A Petrovski

The paper deals with the problem of managing the supplies of consumables (energy resources, lubricants, explosives, explosive supplies, tires, spare parts, etc) in mines. After the introductory remarks and comments, a general stochastic model of supply, relating in general to the dynamic programming method is presented. A selection of stochastic supply model for experiments and research by the authors of this paper is not a coincidence, based on of their long experience, showing that this type of model is the most suitable to provide support for decision-making and management of supplies of consumables in mines.In order for the problem?of?consumables?supply?management to be reviewed, in whole and objectively from the aspect of risk, experimental tests of the stochastic model in real conditions were performed at the limestone open pit mine æZelenikovecÆ near Skopje, the capital of Macedonia. The scope of the experimental research enabled reliable analysis. The results obtained confirm the efficiency and reliability of the stochastic model and two separate manipulative-operational positions regarding its application, which may have an important influence on the optimisation of supplies.

Sep 26, 2011

By K S. Park, J K. Kim, J H. Park, Y Su

The present study investigates the possibility of the direct removal of oxygen from the Ti-30Ni (wt per cent) alloy melt through the thermodynamic equilibrium reactions at 1623 K in the vertical tube furnace. The deoxidation efficiency of Ti-Ni alloy melt by adding different contents of metallic calcium (Ca) as a deoxidant was evaluated with the binary CaF2-MgCl2 flux. The thermodynamic equilibrium experiments showed that the total oxygen content in the alloy decreased from about 650 ppm to 350 ppm when 3.5 wt per cent Ca was added to the Ti-30Ni (wt per cent) alloy. Alternatively, the effect of flux composition in the CaF2-MgCl2 flux on the oxygen content was also investigated at 1623 K. Therefore, the effect of binary flux systems on the deoxidation ability was compared at 1623 K. According to the results, the flux system with 80 per centCaF2– 20 per centMgCl2 exhibited the best deoxidation capability, ie total oxygen content in the alloy reduced from 1450 to 550 ppm.

Aug 21, 2024