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By T Jones, K Karunaratna

The Kalgoorlie Consolidated Gold Mines (KCGM) Fimiston Open Pit is located on the eastern boundary of the Kalgoorlie-Boulder City and is mining an area traditionally known as the Golden Mile. The pit area has been continuously worked since 1893, predominantly by underground mining methods and more recently through open cut mining. There are over 2000 km of old mine headings and numerous stopes under the open pit area. KCGM has interpreted and digitised the underground mine plans and stope sections into a common database. A 2D-model software package, called Pits, was developed in-house and allows old workings to be displayed at any bench level; this is integrated with 3D Vulcan modelling software, which allows triangulated surfaces to be displayed. Almost every mining activity is affected by underground workings. The effective management of the interaction between current mining and the underground workings is very important for safety and production. A specific ævoidÆ management department has been formed and its broad objective is to minimise the impact of underground workings upon production while maximising safety. Special criteria and procedures have been developed and implemented to keep personnel and machinery from being exposed to unsafe ground. It is of primary importance to accurately define the location and outline of underground workings in advance. Probe drilling has been used as the key tool for that purpose. Various geophysical methods have also been trialled on site to detect underground workings; these are discussed in some detail. This paper discusses ævoidÆ management issues such as data integration, void detection and flagging. The impact of underground workings on mine planing, production and slope stability is also discussed.

Jan 1, 2003

The coastline is. an incomparable stretch of sea coast known as Ninety Mile Beach. Two gas pipelines and two oil pipelines carrying hydrocarbons from thb'Bass Strait fields to the markets of Australia cross this beach. They cannot be seen as they are laid in trenching stretch- ing many miles out to sea and the beach was restored to its natural state. Even where the dunes were disturbed, suitable grass was sown thus consolidating the sand and preventing erosion. Ninety Mile Beach is but one of the many key.wildlife and recreational areas that our operations must be concerned with. Others include Westernport and Corner Inlet, but the one discussed in this paper in particular is the platform area of the Bass Strait itself. Never was the old adage "an ounce of prevention is worth a pound of cure" more meaningful than in offshore oil production. All are well aware of some of the events of the past several years that resulted in large and costly oil spills. Far less is known, seen or publicised about the measures and developments that are undertaken to ensure that such events do not occur. We also have well developed plans for response in the event of an emergency situation, which can be initiated with great rapidity. Our responsibility is to ensure that with the best of engineering technology and operating procedures, spills do not occur.

Jan 1, 1971

By Hindmarsh G

The colliery is owned by the BHP Collieries Proprietary Ltd., the principal shareholders being the Broken Hill Pty. Company Ltd. and Hebburn Limited.It is situated due west of Newcastle and 6 south-east of Cessnock, N.S.W., and is conneeted by 36 miles of railway to the port of Neweastle. Of this mileage, 3 miles are owned by the Company, 3 by Hebburn Limited, 9 by the South Maitland Railways Ltd., and 21miles by the Government Railways.The seam worked is known as the Main Greta Seam of the Greta Coal Measures and is on the southern slope of the Lochinvar anticline.At the shaft, the seam is 1190 ft. below the surface, and the section of the coal measures is:-Upper or Main Seam, . 24 ft. 0 in.Conglomerate and shale 70 ft. 0 in.'Middle Seam 8 in.Conglomerate 25 ft. 0 in,Bottom Seam 1 ft. 2 in.These lie between two marine measures, and are the lower coal series of the permo-carboniferous period.Only the upper seam is workable in this area, the lower seams being too thin for eompetitive working. The section of the workable seam at the shafts is as shown on Fig. 1.Unfortunately, only the lower 12 ft. 5 in. of the seam is saleable.

Jan 1, 1935

By Paton T. P

In the technical sense, as well as in the professional sense, the word 'model' can have many meanings. More than 23 000 references were uncovered by a simple literature search on keywords ' MO D EL#. and. (META LLURG#. or. M I NERAL#)' . For the purpose of this paper, 'models' will be considered to be mathematical formulations which attempt to represent or approximate a process. The model may be purely, or a combination of: ò fundamental models, based on the laws of physics, chemistry and thermodynamics; ò semi-empirical or phenomenological models, where an intuitive concept of the process is formulated and found by testwork to fit observed behaviour; and ò empirical or 'black-box' models (including neural networks), where a mathematically convenient form is proposed and fitted. Even under this more restricted definition, which eliminates heuristic and statistical 'models', it is clear that the efforts expended in devising and using models have exploded during the years since the first APCOM Conference in 1961, benefiting from the dramatic decrease in the cost of computer power. This paper reviews the areas of usage of computer modelling in the metallurgical and mineral processing industries, from plant design, through off-line support, to on-line modelling and automatic control. In each area, frontiers of new development of the technology are mentioned. It is noted that, while modelling is now standard practice in design, it is not yet the norm in operating and controlling plants. The reasons for this partial acceptance are, it is argued, less related to the limitations of the technology than to the human and organisational factors involved in transferring technology to implementation.

Jan 1, 1995

The authors have succeeded in providing additional rigour and clarity to the formulation and execution of the dynamic programming algorithm for optimum open pit limit determination. The inclusion of the blocks on the J + 1 column in the search for Pmax, and constraining this search with blocks assigned a value of negative infinity, ensures an optimal solution within the defmed blocks. The effect of the negative infmity blocks is to preclude mining along the diagonal blocks from the first row that they occur in. Figure 1 graphically illustrates the effects of this on the calculation of P. A practical application for constraining mining with negative infmity blocks is the case where the pit outline is defined by lease boundaries and not by the value of blocks to be removed. Any legal, social or physical constraint could be accounted for in the same way.The danger in applying this technique is that the negative infinity blocks will override any other more profitable solutions that may exist. This is in fact what has happened in the example that the authors use. If a further column is added to the left hand side (column -1) and the calculation is carried out again, a more optimal x-section can be found. (If the negative infinity values are removed the same result is obtained.) This gives a pit value of 112 as against the 108 of the authors' optimal pit. This calculation is shown in Figure 2. Lerchs-Grossman optimization is reliable only if there are sufficient columns available to allow "mining" to optimum depth of the ore body and still allow the pit to break out at the surface within the confines of the columns.This author's approach is to create enough columns each side of the lateral limits of the ore to allow the pit to intersect the surface while still within the confines of the block model. Implementing the methods discussed by the authors helps to reduce the number of columns required to achieve this.

Jan 1, 1987

The Agnew Mine No. 1 Ventilation Shaft is the largest diameter shaft blind drilled in a hard rock mining environment. The selection of this method of shaft development was based on achieving an accelerated mine development and exploration programme. Drilling the shaft from a pre-sink depth of 73m commenced on March 22, 1982 and the shaft was stopped due to rig structural problems at a depth of 750m, 280m from the designed depth, on February 12, 1983, 137 days behind schedule. While problems with rig mechanical availability, cutter life and lost drilling tools in the hole hindered progress and escalated costs, penetration rates above prediction were achieved and both the speed and safety aspects of the method were well demonstrated.

Jan 1, 1983

A study is presented of the theoretically possible initiation systems for outbursts and the subsequent propagation mechanism.Previous occurrences of outbursts and their correlation to the theoretical system are described. An estimation of the energy release from two energy sources, gas strain energy and rock/coal strain energy, is presented and the relative importance of each source in the severity of outbursts. Summary: The description of mechanisms of outbursting follows the examination of these phenomena at Collinsville in Bowen No. 2 mine and at Leichhardt Colliery, Blackwater. Quantitative material contained in the paper refers to Leichhardt Colliery, Blackwater. Clearly from the work carried out to date gas release has a major part to play in the out- bursting at both of these collieries. In the case of the December 1 1978 outburst at Leichhardt Colliery energy release estimates place gas strain energy release contributing eight times the energy of that from rock/coal strain energy. Even the normal outbursts at Leichhardt Colliery appear to show this trend. Estimates of energy released are for comparative purposes between gas and rock strain energy and the values obtained may be regarded as approximate.

Jan 1, 1980

Solar Salt, Lunar Ambitions I Bauerti The title of this paper is `Solar Salt, Lunar Ambitions'. It is largely the result of a lack of imagination and a tight deadline. I was seeking a catchy title to convey the image of being 'here' and wanting to get `there', with `there' being a long way away and our being held 'here' by powerful gravitational forces. I tried `Solar Salt, Lunar Landings', but that implied we had already reached `there' when, on reflection, we had not. A colleague suggested 'Solar Salt, Luna Park' which is a fun park in Sydney and, I must admit, there was appeal in the image of having embarked on a wild roller coaster ride with stomach-wrenching twists and turns and the only reward being a pair of sweaty palms, and a feeling of nausea. That's sometimes how it feels when you launch into change. In the end I settled for the more sedate `Lunar Ambitions'. It contained that suggestion of hope and continual striving which are central to the idea of best practice. I will discuss our experiences in this area shortly, but I would firstly like to provide some background to our business. The salt industry is steeped in history and tradition. As one learned commentator observed, common salt is 'a substance seemingly too ordinary to think about, yet it is the oldest of man's raw materials and the basis of some of his newest inventions' (Multhauf, 1978). From ancient times, salt was recognised as a key necessity of life and it has played a role in the rise and fall of governments throughout history. The Romans recognised its importance when they gave their soldiers money regularly to purchase salt, hence our modern word 'salary'. Today, while culinary use remains important, the main consumer of salt is the chemical industry (Figure 1).

Jan 1, 1995

By M Dorricott

This paper describes the design, construction and performance of sill pillars using cemented development mullock at the Crusader Gold Mine. The orebody is some 35 m - 60 m in length, 5 m - 8 m wide, dipping at 60¦ - 85¦ and plunging at about 40¦ to the north. It is accessed via a footwall decline. The ore occurs at the contact between basalt and ultramafic. This contact is characterised by shearing and alteration; and is prone to unraveling failure. The cut and fill mining method at Crusader extracts 25 m high ore blocks in four flat back lifts and one 8 m thick crown pillar. To enable full recovery of these high-grade crown pillars with minimal dilution, a 5 m thick sill pillar is constructed using cemented rock fill (CRF), after mining of the bottom two lifts in each block. Uncemented development mullock is used as rock fill (RF) for subsequent lifts. Development mullock and cement/water slurry is mixed underground to produce CRF. The fill is transported to the stope in LHDs and dumped on the floor. The sill pillar is advanced progressively, with compaction provided by the loader driving over the previously placed fill. Old jumbo rods are installed as shear pins along the flat dipping hangingwall to reduce the risk of rotational failure of the pillar. A fan of cable bolts is installed into the hangingwall to prevent unraveling failure in the sheared ground. Buffer blasting is used to minimise damage to the CRF sill pillar when the crown pillar below is extracted. At the time of writing, extraction of the crown pillar underneath the CRF has taken place at the 930 stope. The crown pillar was extracted successfully with dilution from the backfill and hangingwall minimised and 98 per cent of the gold recovered. This compares with pillars that were mined beneath uncemented backfill where only 70 per cent of the gold was recovered and where there was significant dilution from the backfill and from hangingwall failures. Where no CRF was placed, there were also numerous production delays caused by large rocks from the hangingwall blocking the stope brow.

Jan 1, 2002

By Denby B, Miles N. J

The underlying theory behind the construction of an on-line size analysis system is described together with an introduction to the Artificial Intelligent techniques that it is founded on. Previous systems based on more traditional technology such as edge detection and dilation algorithms have been restricted by the significant processing power they require, this has resulted in the production of systems with either reduced functionality or severe hardware requirements. A neural network approach offered a new perspective to the problem of size analysis; the ability of a network to learn and recognise subtle patterns in training data before on-line processing is initiated opened up the possibility for the production of a fully functioning practical system. The format of the training data had to be carefully analysed prior to its implementation in a neural network as the capability of a neural network solution depends as much upon a suitable data preparation as it does on the system architecture. To facilitate experimentation with various profile quantification techniques such as fourier and fractal analysis an Image Profile Analysis System was constructed (IPAS) in software on a personal computer. The IPAS system was produced with the aim of pre-processing image data to create data sets for experimenting with external neural network packages. The system allows the analysis of both real images obtained by image capture and simulated images created by an in-built in simulator. A measurement comparison scheme is also included together with a case study concerned with the frequency analysis of simulated images. The power of neural networks combined with the data compression provided by profiling removes the need for direct measurement of individual particles. This has obvious implications on the level of hardware necessary, and ultimately the expense of a stand alone system. The extrusive nature of data collection via an image analysis system will also permit simple installation of a shipped system; eliminating any requirement for interference with existing machinery.

Jan 1, 1995

By M Lund

Due to operational and regulatory practicalities, pit lakes will continue to be legacies of many open cut mining lease relinquishments. Unplanned or inappropriate management of these significant geographical features may lead to a short-term liability to all stakeholders during mining operations, or to ongoing liability to the local community and environment following lease relinquishment. However, the potential for pit lakes to provide benefit to companies, communities and the environment is frequently unrecognised and yet may be a vital contribution to the sustainability of the open cut mining industry. Improved remediation technologies are offering more avenues for pit lake end use than ever before, at the same time mining companies, local communities and regulatory authorities are also becoming more aware of the benefit these water resources have to offer. Sustainable pit lake management aims to better minimise short- and long-term pit lake liabilities, and yet also to maximise short- and long-term pit lake opportunities as well.

Jan 1, 2006

China has abundant bauxite resources, but these resources are mostly of a diaspore, which has a feature of low Al2O3 to SiO2 mass ratio, typically ranging from four to six. Compared to other materials, this kind of raw materials consumes more alkaline and energy in the process of metallurgy, and incurred a high alumina production cost. To solve this problem, researchers in China have done a lot of work on removing of the silicon from bauxite. Under the impetus of these works, in 2003, the first flotation plant of diasporic bauxite in the world was constructed in Zhongzhou, Henan, China. Seven years of operating experience shows that this technology can signifi cantly reduce the costs of following-metallurgy processing. These efforts are an important reference for the processing of similar resource. In general, for Western scholars it is diffi cult to fully understand these works because most of them are published in Chinese. In this paper, a detail introduction for the research progress on China bauxite de-silica flotation was presented, these works involved crystal chemistry, wettability of bauxite minerals, collector and modifi er in bauxite fl otation and flotation practice, etc.

Sep 13, 2010

By Watsford RMS, Wickham P

In October 1980 the two existing flotation circuits were combined into a single new circuit. This circuit used modern 11.3 m3 flotation cells which replaced 1.4 m3 units. Sometime after this change, a significant deterioration in metallurgical performance occurred. This paper describes the work done to discover the causes of deterioration in performance and actions taken. The program implemented to prevent a future occurrence is also presented. The work included analysis of routine plant data, analysis of surveys to obtain element and mineral flows on both a sized and unsized basis, some quantitative mineralogy, and analysis of some external factors.

Jan 1, 1978

By I Taylor, M Nugus, C Gordon

Resource estimation and selective mining of structurally complex, high nugget orebodies presents a major challenge to the Mine Geologist. At the Golden Pig BIF-hosted gold deposit in Western Australia, an estimation method has been developed that replaces an assay-based resource estimate with one based on mineralisation intensity. Subjective coding of the mineralisation intensity has a more robust connection to local grade than drillhole assays. Indicator variograms of the five mineralisation codes are well structured with anisotropy directions similar to observed structural controls. The proportion of each mineralisation code is estimated and a weighted average of the average grade of each code calculated for a block. Initial validation has shown that the model is a good predictor of the mineralisation intensity, and the application of appropriate local average grade for each mineralisation code gives a reliable block grade estimate.

Jan 1, 2003

INDEX OF CONTENTSComposition of the Brown CoalsIntroductionComposition as minedComposition from drilling explorations:Latrobe Valley Area, East Gippsland, Welshpool-Alberton West Area, Altona-Bacchus Marsh Area, Lal Lal Area, Dean's Marsh Area. The Coal Constituents:Vitrain, fusain, detrital coal, resin, Sulphur, types, distribution, Ash, composition, sulphur, phosphorus, chlorine,,titanium, vanadium, distribution in seam, fusibility, source, mineral ash, chemical ash Bitumen, tar. Factors causing Variation in Composition:Pressure of overburden, moisture content, carbon, hydrogen, nitrogen, oxygen, calorific power, density, compression by warping, abnormal moisture, initial differences in vegetation, conditions of sedimentation, weathering before re-burial.Summary and AcknowledgmentsList of References

Jan 1, 1945

Three major and two minor uranium deposits 'have been worked by open out mining since the discovery of ,the Rum Jungle field in 1949. Total production has been about 9679000 tons of uranium ore at 7;39 lb U308/ton and 4029000 tons of copper-uranium ore at 6.27 lb U308/ton and 2.7% Cu, with significant tonnages of base'metal ores. The deposits occur in or near black pyritic slates of the Lower Proterozoic Golden Dyke Formation, near the contact with the under- lying Coomalie Dolomite. The mineralization is probably younger than the grahite complexes in the area, and a structural-stratigraphic control of ore deposition is used as a basis for uranium exploration.\

Jan 1, 1968

ADDRESS BY THE PRESIDENT OF THE INSTITUTE (MR. J. G. SYMONS) IN PRESENTING THE CERTIFICATE TO ROBERT COLVILLE BRADSHAW, O.B.E.Today it is my privilege and pleasure to introduce to you, Robert Colville Bradshaw. O.B.E., the third New Zealander to be honoured with Honorary Membership of The Institute. Sir William Hudson and Mr. C. H. Benney were the others.Mr. Bradshaw has been an Affiliate Member of The Institute since the formation of the New Zealand Branch in 1966. Like his friend Matt Benney. Bob Bradshaw is an accountant by training. Last June he retired as senior partner of the firm of chartered accountants, now known as Wilkinson Wilberfoss, with which he served from January 1929.Mr. Bradshaw grew up in New Zealand attending the Terrace School in Wellington, the New Plymouth Boys' High School where he was a boarder, and completing a Bachelor of Commerce at the university now known as the Victoria University of Wellington. He is an elected Fellow of the New Zealand Society of Accountants and an Associate of the United Kingdom Institute of Cost and Works Accountants.

Jan 1, 1977

By Mathews K. E, Willstead T. V C

Initial glory holing was followed by sublevel stoping, with a small proportion of total production mined by shrink and cut-and-fill methods.The sublevel stoping method was successfully modified to cater for altering ground conditions encountered at increasing depths. At present, 94 per cent of production comes from sublevel stopes. The evolution of this mining method and current techniques and practices is outlined. A combined shrink and,sublevel benching method was also developed to increase the mining rate of narrow orebodies over the standard stoping lift of 380 ft. Pillar recovery and stope filling operations have been continuously modified to suit the relIuirements of a rapidly developing mine.INTRODUCTIONOre production commenced at Mount Isa Mines in June 1931. Since then production has increased from approximately 2,500 tons of lead ores per mine day to the current 11,000 tons of sulphide ores per mine day comprising 3,100 tons of lead ore and 7,900 tons of copper ore. The early planners selected sublevel stoping with ring drilling for ore breaking as the most efficient and economical for Mount Isa conditions: This method satisfied requirements for:1. a low cost mining method for the comparatively low grade ores,2. a stoping sequence allowing development, stope preparation, breaking and drawing of ore to proceed concurrently,3. a method of extraction in which broken ore in the stopes would be kept to a minimum because of adverse effects of oxidation on mill metallurgy and...

Jan 1, 1961

This paper considers three aspects of cemented fill practice and research in Mount Isa. Firstly, an account is given of the use of Portland cemented hydraulic fill both in MICAF sills and in recovery of major horizontal pillars in the 650 copper orebody, where, during mining, cemented fill has regularly been exposed on unsupported vertical faces up to 90 ft high. In the paper the main considerations are the role and specifications of the fill used but also included is a brief description of fill preparation and placement.Data resulting from a Portland cemented hydraulic fill sampling, curing and testing campaign covering about 18 months of operating practice are presented, analysed, and discussed. These yield information indicating the mode of operation of a fully-automated fill preparation station, as well as a means of comparing field and laboratory strength results. A technique with potential for use as a fill quality control without actual strength testing is also described. The data collected showed that the fill station can operate within tolerances set on product quality, that laboratory and field strength results are comparable, and that rapidly obtained fillsample properties such as moisture content and void ratio can be related to cement content and strength, and hence used for quality control.Results of a fill research programme conducted by the author in Mount Isa since early 1968 are presented involving Portland cemented hydraulic fill and alternative, cheaper additives for cementing hydraulic fill. The most significant alternative to Portland cement is quenched and ground copper reverberatory furnace slag, whIch behaves as a pozzolan, reacting strongly with any available lime to produce cementitious hydrated calcium silicates and allowing Portland cement reductions of at least 50 per cent without strength loss.

Jan 1, 1971

By J Araya, O Leiva

The mine evaluation process, composed of the designing, planning and valuation of a mine project, is, among other variables, based on an estimated orebody model. However, as the information from the drill holes is limited, it is impossible to know with certainty the mineral content in each block within the estimated block model. Consequently, uncertainty about the value of metal grades, or other geological attributes, arises because of the lack of information at unsampled locations. This is one of the reasons why, in any mine operation, there will always exist a divergence between estimated and real values. Cut-off grade optimisation is the process used to determine the operating mining strategy (long-term production scheduling) that will maximise the total profit value (normally referred as the net present value (NPV)) of a mine operation. This is done by defining a dynamic cut-off grade policy which is constrained by the production capacity of the mining, mill and refining.Real options is a type of contract, written on real assets such as mining, oil and other natural resource industries, that gives you the right but not the obligation to exercise the contract. It is based on operational and managerial flexibility, which allow mine decision makers to react to either good or bad operational and economic events in the future. But, what do geostatistics and cut-off grade optimisation have to do with the application of real options in a mine project evaluation process? The objective of this paper is to answer the previous question by showing how geostatistics combined with cut-off grade optimisation are key tools for corporate/managerial decision makers, which allow them not only to analyse the resource/reserves of their projects, but also to generate operational strategies that can maximise project value by minimising the downside risk due to ore tonnes and grade uncertainties, while achieving operational and physical constraints such as mining and processing capacities. A real copper grade open pit mine project is used as a case study.

Sep 26, 2011