Search Documents

By D J. Bradshaw, B Lottermoser, A Parbhakar-Fox

"Best practice for acid rock drainage (ARD) risk assessment still relies solely on the geochemical properties of sulfidic rocks and mineral processing products, despite the fact that a rockÆs tendency to produce acid also depends on mineralogy and texture. Consequently, there are a plethora of geochemical tests routinely utilised by the mining industry to predict ARD formation. Due to limitations associated with these tests and their relatively high costs, analysis of recommended best practice sample numbers is rarely achieved, reducing the accuracy of waste management plans. Our research addressed this through examining the application of geometallurgical data for predicting acid formation, and led to the identification of potential environmental geometallurgy indicators.Samples obtained from an iron-oxide copper gold deposit were subjected to the geochemistry-mineralogy-texture (GMT) approach, an improved methodology for classifying acid forming potential. GMT results were compared against geometallurgical and assay data sets to evaluate: relative carbonate content measurements (measured by HyLogger) and identify how these could be used to calculate effective acid neutralising capacity mineral hardness (measured by EQUOtip) to determine application of this data for calculating lag-time to acid formation opportunities to automate the acid rock drainage index (ARDI) using classified images produced by a GEOTEK logger and automated microscopy.Links between the GMT approach and geometallurgical data sets were identified. Classified mineralogy data has application at stage one, HyLogger and EQUOtip at stage two and computer-based ARDI evaluations of classified images at stage three. Through such integration, ARD characterisation costs can be reduced, with value added to geometallurgical data sets. Furthermore, deposit-wide ARD domaining is possible, and acquisition of total-orebody knowledge more likely. Through adoption of this environmental geometallurgy approach, a better informed waste management plan can be formulated, allowing for best practice ARD sampling in a more cost-effective manner.CITATION:Parbhakar-Fox, A, Lottermoser, B and Bradshaw, D J, 2013. Cost-effective means for identifying acid rock drainage risks - integration of the geochemistry-mineralogy-texture approach and geometallurgical techniques, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 143-154 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

Two years ago I was sitting in a big lecture theatre at the School of Mines in Kalgoorlie at the annual New LeadersÆ Conference listening to a guy tell us all how much he loved his job, travelling the country ælegallyÆ blowing stuff up à and getting paid to do it. I would have paid to see and do the things he spoke of à now IÆm that guy. From finishing a mining engineering degree at the University of Ballarat, through the job hunt, to firing environmental blasts in Tassie and designing and implementing construction blasts in the middle of the Gold Coast. My name is Rohan Stevens and IÆm a blast-o-holic. While the æjob huntÆ we all embark on toward the end of our degrees is a stressful time, itÆs also very exciting in the current climate. There are a number of things I have learnt through both my hunt for the job that best suited me and working for the worldÆs largest explosives manufacturer. If at least you donÆt benefit from my learnings IÆm certain you will enjoy hearing about (and viewing) some of the work I have had the opportunity to be involved with over the last 18 months with Orica Mining Services.

Jan 1, 2008

By K Aikawa, M Ito, K Mitsuhashi, Y Ebisu, J V. Satur, I Park, N Hiroyoshi, T Suto

Copper concentration using flotation is becoming more difficult, because of an increase in ore complexity accompanied by smaller grain sizes of copper minerals than usual, requiring finer grinding in order to liberate them. Project Arqueros, located at the mid northern part of Chile, is a copper mine project with an orebody consisting of various sulfides such as chalcopyrite, chalcocite, and bornite. Some of the copper minerals in Arqueros show low floatability mainly because of their fine grain size and resulted fine grinding size, and also because of the complex mineralogical composition. For example, chalcopyrite in Arqueros floats less than the other copper sulfide minerals. In this study we carried out some kinetic flotation tests with the Arqueros ore using a laboratory-scale forced air type flotation machine by varying the regrinding size. The products were assayed and mineralogically analysed to compare the minerals in their flotation behaviour with respect to size classes and liberation classes. The results were compared with a model calculation according to bubble size measurement. From the flotation testing and mineralogical analysis, it was found that copper minerals of the same size and liberation class floated at the same rate even with different regrinding size. At the same time the comparison between experiment and calculation showed that the fine particles of less than 5 µm size floated faster in actual than in the model applied. These results suggested that interactions among minerals of different species and of different sizes had positive impacts on the flotation rate of the fine particles. It indicates that this phenomenon can be applied to improve copper recovery in the project.

Aug 24, 2022

This paper describes modern long-term mine scheduling and gives an example of its application. It then discusses the obstacles to the implementation of such schedules.

Sep 26, 2011

By A T. Spathis, M L. Lawlor-O’Neill

A methodology for the inversion of a scaled charge weight superposition model to predict peak particle velocity (PPV) has been examined. The inversion involves two steps: first simulated annealing is used to get an initial estimate of the model parameters; and second, these parameters are used as input to a quasi-Newton non-linear optimisation method, used to refine the value of the parameters. The methodology recovers the three required parameters (two charge weight scaling parameters and a time window width) and does this directly from a single production blast for a given point of interest. It has been tested on a synthetic example and recovered the input model parameters successfully in the presence of introduced noise with a coefficient of variation ranging up to ten per cent. Another test used the vibration measurements of three tunnel blasts monitored during the construction of the Citybanan tunnel in Stockholm. In this case, the three model parameters are found from one blast and for a given point of interest, and the PPV at the same point of interest is predicted for the second and third blast fired in the same vicinity as the first blast. The three blasts used different firing sequences. The predicted PPV limits use a confidence interval determined from the scatter in the peak levels obtained from the single calibration blast. The methodology was able to predict an upper bound for the PPV in 21 of the 26 tunnel blast vibrations studied. These predictions improve on a previous study involving the same model but which did not use the inversion process above. Given this reasonable success, further testing of the method on other data sets and alternative forward prediction models is recommended.CITATION:Lawlor-O’Neill, M L and Spathis, A T, 2015. An inversion method for the prediction of peak particle velocity in blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 97–108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The Bureau of Mineral Resources has been engaged in regional geological and geophysical field work in the Alligator River and Cobourg Peninsula area since 1971, following the discovery of major uranium deposits. Geophysical work commenced with a regional airborne magnetic and radiometric survey which was followed up by some helicopter and ground work in August 1973. The interpretation of the earlier radiometric work is presented in conjunction with the results obtained from the follow-up work. Analyses of 100 outcrop and drill core samples collected have provided basic information on the physical properties and concentrations of uranium and thorium in various rock types. The uranium determinations were made by X-ray fluorescence and delayed neutron analysis, good agreement being obtained between the two methods. X-ray fluorescence was the main analytical technique used because of its ability to produce both uranium and thorium determinations.

Jan 1, 1975

Most coal mines in Chongqing Area are highly gassy mines and liable to outburst of coal cnd methane. In order to harness mine environment and raise the Prodction capacity, methane predrainage is generally taken as a main preventive measure against outburst by all mines. In the recent ten years, the drainage volume per year has increased from 38.25 million m3 to mote than 100 million m3 with a volume over 12 m3 per tome of coal. In some mines, the draining rate is approaching to 50 percent, the rate in mining districts is up to 60 to 70 percent. The predrainage volume accounts for one fourth of total drainage volume. All these have effectively prevented the occurrence of coal and methane outbursts.This is the current situation of methane predrainage in coal mines in Chongqing area, the methods of predrainage to prevent outbursts and related parametres comprise:1. methods, technologies, supervision and effect of predrainage in different geological and mining conditions,2. the change of methane parametres pre-and post-drainage and the analysis of the effect of methane predrainage to prevent outbursts, and3. ways to improve the effect of methane predrainage.Thus the safety, reliability and production of Changqing Coal Mines will be enhanced.

Jan 1, 1991

By J J. Van Wijk, A R. Penney

Successful management of geotechnical risk at a mining operation is more than just having a good ground control management plan or using advanced numerical modelling and the latest monitoring technologies. The fundamental requirements for effective geotechnical risk management include identification of potential failure modes, identifying and implementing appropriate controls, and demonstrating the effectiveness of those controls. Effective geotechnical risk management requires an integrated approach by confirming that appropriate risk management systems have been identified and implemented (management plans, procedures etc), and that these systems are executed consistently in the field across all working areas. Development of a thorough integrated auditing process executed by an experienced team of technical subject matter experts with substantial operational knowledge, provides a more complete picture of catastrophic hazard management. Following consistent evaluation criteria allows benchmarking of systems and implementation compliance between the sites being audited, and the results can then be ranked against other operations in an industry database.

Nov 29, 2022

By B King

A large number of mineral deposits contain regions in which it is economically beneficial to extract ore both via open pit and underground mining techniques. Current industry practice lacks an effective means to establish the extent of the open pit and underground mining areas for an individual deposit. We present a mixed integer programming model for scheduling both the open pit and underground mine that can be used to create a holistic extraction sequence for a specific deposit. The model considers both spatial and temporal elements of the open pit and underground mines in order to maximise the net present value of the entire deposit, while adhering to its production, processing and block sequencing constraints. By doing so, we can schedule the open pit and underground in concert.CITATION:King, B, 2014. Modelling open pit and underground production scheduling in concert, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 369–374 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By Green A. D M

The establishment of the Imperial Smelting Furnace at Sulphide Coporation Pty. Limited for the smelting of zinc and lead made it necessary to design and install sintering capacity to produce approximately 500 t.p.d. of zinc-lead sinter. The updraught sintering process installed is a recent development and the plant was designed with adequate flexibility and equipment to enable operating staff to investigate the process and achieve maximum production under optimum operating conditions.Sulphur dioxide gases from the sinter machine are passed to a contact acid plant for the manufacture of sulphuric acid.

Jan 1, 1964

By K White, C Ferguson, M Harding

Understanding watercourses and river processes at a landscape scale is vital for managing risk to mining infrastructure and operations as well as minimising future environmental impacts beyond the life of the mine. Recognising this, Iluka Resources Limited engaged Alluvium Consulting Australia to identify and characterise watercourses across several neighbouring mineral tenements in the Eucla Basin, South Australia (Alluvium, 2013, 2014a, 2014b). The objective of the studies was to inform planning for risk management during mine planning and operation and appropriate landscape rehabilitation for mine closure.Mining operations in the area are by open cut extraction of mineral sands. The extracted resource is processed on-site before leaving the site for export. Several pits are to be developed in stages with simultaneous backfilling and surface reinstatement. Mining is initially taking place in the Jacinth tenement, where up to 100 km of watercourses may be directly or indirectly impacted (refer to Figure 1).The total study area (shown in Figure 1) is approximately 330 km2 and spans three smaller areas that were the focus of separate investigations during mine planning.CITATION:Ferguson, C, White, K, Harding, M and Hardie, R, 2016. Landscape-scale assessment of watercourses in remote arid South Australia to inform mine planning to mine closure, in Proceedings Life-of-Mine 2016 Conference, pp 200–204 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By R Razanatsimba, A Galli

A mining company has entered into contractual commitments to supply certain quantities of its product to clients in each time period. Failure to fulfil its obligations would damage its reputation as a reliable supplier. The planned production would normally be sufficient unless major problems such as highwall failures, roof falls, natural disaster, or strikes that interrupt production or delays in obtaining environmental permits, occur. To overcome these difficulties, the company may be able to obtain more of the commodity: from its strategic stockpile (if there is sufficient there); by buying it on the spot market; or for some commodities such as gold and uranium, by leasing it. Two sources of uncertainty, the spot price of the commodity and the occurrence of serious incidents that interrupt production, are considered. For simplicity it is assumed that the commodity price follows a geometric Brownian motion, that productions incidents have a binomial distribution, that they are independent from one time period to another and that they do not affect prices. A branching tree structure is used to model the joint evolution of prices and production incidents. The aim of this research project was to evaluate the companyÆs options for fulfilling its contractual commitments. When evaluating these options, multi-stage stochastic programming with recourse was used to solve this problem because in addition to providing the dollar value of the project, it gives decision-makers the æroadmapÆ to reach the optimal value. That is, how much material should be bought/sold on the spot market, how much to add to/subtract from the stockpile, how much to lease and in the worst case what the shortfall would be, for each time period as a function of the current spot price and breakdown status. A case-study over a five-year period is used to illustrate the proposed procedure. In this study the production would be sufficient to cover the companyÆs contractual commitments unless production incidents occur. Focus is on evaluating the impact of the quantity initially in the stockpile on the value of the project when the commodity market is tight, that is, when only small quantities can be bought on the spot market or by leasing.

Sep 26, 2011

By N Maistry, C Carelse, A Singh

Banded Iron Formations or more commonly known as BIF are sedimentary rock formations with alternating silica-rich layers and iron-rich layers that are mainly composed of iron oxides (hematite and magnetite), iron-rich carbonates, and/or iron-rich silicates. Considering the depletion of highgrade iron ore reserves in South Africa, there is a need to maximise resource utilisation through the exploitation of low-grade/uneconomic resources particularly BIF material, which makes up more than 65 per cent of current reserves. Previous test work conducted by alternative BIF sources globally indicates the need for fines processing in order to produce a concentrate. South African BIF however is amenable to coarse and fines processing producing an on-grade product or blended feedstock. C-Type material within South Africa’s Northern Cape Province grading at approximately 33 per cent Fe was supplied for research purposes. Top size optimisation via gravity Heavy Liquid Separation (HLS) tests was conducted. The laboratory results being perfect separation (Ep=0) were modelled to predict pilot performance, the results of which were tested on a pilot scale for the finest size fraction (-1 mm). It was observed that a top size of -2 mm provided optimum results in terms of upgrade and recovery, with crushing finer not necessarily producing superior results. At a target grade of 60 per cent Fe, recoveries of 65.6 per cent were achieved on the laboratory scale, whilst recoveries of approximately 58 per cent were achieved on the pilot scale. Targeting higher upgrades of 63 per cent would inevitably result in lower recoveries of 57.2 per cent on a laboratory scale and approximately 54 per cent on a pilot scale. This is in line with grades and recoveries achieved globally for BIF material albeit at finer grind sizes.

Sep 18, 2023

By H Y. Niu

The coal left in the goaf is easily submerged by groundwater damage. During the mining process of the underlying coal seam, it is necessary to drain the water in the overlying goaf. The coal sample is prone to spontaneous combustion after being soaked in water and air-dried. To explore the effect of micro-functional group transformation of water-immersed coal samples on the spontaneous combustion characteristics of coal samples during the low-temperature oxidation process. Using the experimental method of infrared spectroscopy, the migration law of special functional groups under different oxygen concentrations of water-soaked coal samples was analysed. By means of thermal analysis, the endothermic and exothermic properties of the functional groups in the water-soaked coal samples were studied. The results show that: the higher the oxygen concentration, the more oxygen-containing functional groups in the water-soaked coal sample, compared with the 18 per cent oxygen concentration, the 14 per cent oxygen concentration has a small increase, and the chain length is shortened. The temperature increase together with the oxygen concentration content determines the functional group content, the pyrolysis process produces some functional groups. The lower the oxygen concentration, endothermic rate decreases and endothermic temperature increases, the higher the ignition temperature of coal oxy-combustion, the lower the total heat release, the higher the burnout temperature, and the faster the oxygen-absorbing weight gain and the conversion of functional groups. Below 14 per cent oxygen concentration, the oxidative combustion process will be greatly reduced. The results provide a theoretical basis for preventing long-term water-soaked coal body oxidative spontaneous combustion in shallow buried coal seams.

Oct 12, 2022

The movements of the major continental cratons and the distribution of the principal tectonostratigraphic terranes are reviewed in the Circum-Pacific region during Phanerozoic time. It is concluded that major periods of orogeny and consolidation of accreted terranes in the Circum-Pacific region is best correlated with periods of advance of cratonic blocks over the Pacific Ocean basin combined with relative convergent to transpressive motions between the cratons and the Pacific Ocean plates. Continental collisions and collision of terranes with continental margins has not been a significant geodynamic process in Circum-Pacific tectonic evolution. The permanency of the Pacific Ocean basin throughout 500 MA is remarkable. It appears no continental block or large continental fragment has ever entered or crossed the Pacific Ocean basin since early Paleozoic time. This area where no continent has entered for 500 MA is almost coincident with the present Pacific Ocean basin and seems associated with the 25 to 100 meter geoid high which dominates the present-day figure of the Earth.

Jan 1, 1990

By B McCarthy

Mining has been typified of late as a boom and bust, cyclical industry operating against a steady decline in the size and quality of mineral deposits. Decreasing deposit grades and increasing costs of traditional mining techniques, all in the face of another commodity downturn, are forcing mining companies more than ever before to seek out new and innovative ways to operate. New technologies are emerging to model, control and track resources through the mining value chain, to move material about mines more efficiently, and to identify and separate ore from gangue early in the extraction process.Discovering such technologies however is only the first challenge for mining companies. Actually implementing technological change successfully has proved to be an even bigger challenge. Like for many industries, fulfilling the promised benefits for the expense and timing envisioned, has not been easy when innovative technologies are introduced.Citing the author’s insights and experiences in a number of emerging technologies, this paper explores barriers to implementing technological change in the mining context. Key elements of a change management framework, first developed for implementing mine management systems, are described to give mining executives insight into how they and their organisations can succeed through technology-driven change.CITATION:McCarthy, B, 2016. Successfully implementing technology-driven change in the mining environment, in Proceedings International Mine Management Conference, pp 89-104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

The Emmaville district is located in the northern part of the New England region of New South Wales some 400 miles north of Sypney. Better known for its substantial production of tin and tungsten ores, the Emmaville district has also been the centre of a small and somewhat sporadic production of copper, arsenic, silver, lead and zinc. This production has come principally from three mines-Webb's Silver Mine, Webb's Consols and, to a lesser extent, Pye's Creek Silver Mine.The ores from these mixed sulphide deposits are texturally and mineralogically complex and the problems of beneficiation are rather formidable.GENERAL GEOLOGYThe main rock type of the Emmanville district is a dark, brown to blackish massive siltstone of Permian age which overlies acid volcanics possibly also of Permian age. In places the siltstone gives way to conglomerates and standstones with discontinuous lenses of calcareous sediments (David, 1887).The whole series is folded but because of the massive character of the more expansive siltstone, detailed structure is difficult to delineate.Toward the close of Permian time the area was intruded by a series of intermediate to acid plutonic and hypabyssal rocks. Mineralization within the region is ascribed to the more acid of these intrusives-granodiorite, granite, and quartz-felspar porphyry (Lawrence, 1957, 1960).No intrusive rocks outcrop in the immediate neighbourhood of Webb's Silver Mine though granite occurs two miles...

Jan 1, 1961

By T Roberts, S Talu

Steel wire weld mesh is a common industry standard surface support used in underground mining, traditionally installed with mining drills during the bolting cycle. As underground mining depth and stress increase, mining methods and their sequences at these depths place challenges on conventional surface support options. These challenges have provided a need for high capacity surface support options that improve development efficiency, reduce the need for secondary ground support installation and is easily installed with current mining equipment. A 5m2 mesh testing machine was built, suspending a 9500kg concrete slab, designed with multiple hold down points to test varying bolting patterns. Mesh load and displacement is accurately measured using a data acquisition system which pushes against the restrained mesh module with an available 200kN load and 1200mm displacement capacity. A testing program comparing conventional surface support, straps and combinations of both were tested for baseline results. New module designs incorporating existing mesh types and new design concepts were manufactured to allow for single pass installation during a bolting cycle. Nine mesh types, mesh/strap combinations and new mesh module designs were compared using the same test method. Based on these results, two high capacity mesh module types are produced. This paper will detail the test program, load and displacement results and underground mesh module performance, describing the two high capacity mesh modules function within the development cycle and manual handling. CITATION:Roberts, T, Talu, S and Wang, Y, 2018. Design and testing of high capacity surface support, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 303–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By P Holt, M Allen

On the first of July, 2012, the Australian GovernmentÆs Clean Energy Act commenced. From this point, a price of $23/t of CO2-e will apply to facilities that trip the liability threshold. This first part of this paper concentrates on the mechanics of the Clean Energy Future legislation and how it will be applied to the mining and mineral processing industry.The second part of this paper contains analysis of the data presented for typical mine operations. Methodologies for constructing a carbon strategy are also presented. This will entail determining what the objectives of the carbon strategy are, and defining what the strategic priorities for a business should be. An action plan to address the risks identified from the Clean Energy Act is also developed as part of the strategy.Details such as the advantages and disadvantages of opting into the carbon price scheme for liquid fuels are shown. Other considerations such as the ability to acquire permits through the carbon farming initiative or through overseas clean development mechanism projects are explained.CITATION:Allen, M and Holt, P, 2012. Implications of the carbon price and developing a carbon strategy, in Proceedings International Mine Management 2012, pp 105-114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By R Morrison, R Dunn

In many mineral processing operations, the reported production figures for an accounting period may not make the best use of available data. While most of the mathematical approaches, such as check-in/check-out, mass balancing, used in effective metallurgical accounting strategies are well understood, the sources and magnitude of measurement errors generally are not. As part of the æAMIRA P754-Metal Accounting and ReconciliationÆ project, a study was undertaken at the Northparkes copper/gold concentrator near Parkes, New South Wales to examine the data used in their concentrator metallurgical accounting system. This paper summarises the results of a detailed examination of the mass measurement systems around the concentrator as well as the primary sampling system used for grade estimation. The goal of this work was to develop practical techniques to quantify the error (ie both accuracy and precision) of the measured metal accounting information. With this information, statistical confidence levels for this data can then be calculated. If the errors are small, the effect of error in each piece of measured data can then be propagated to other calculated production figures such as recovery and feed grade using a statistical technique called æthe propagation of errorÆ.

Jan 1, 2007