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The Central Andes in Peru, Chile, Bolivia, and Argentina, contain two contiguous terranes which were accreted i, Gondwanaland between the end of the Devonian and the end of the Triassic. These terranes, Arequipa in the north, anni Chilenia in the south, differ from each other in the timing and style of their metallogenic development. However, they contain over 90% of the Central Andean porphyry copper resource. The copper porphyries in the Arequipa terrane are Paleocene to lower Oligocene in age, whereas the Chilenia deposits are mid-upper Cretaceous and mid-upper Miocene. Porphyry copper deposits occur outside these terranes, but are all Miocene in age. Miocene porphyry-style mineralisation also exists in the Arequipa terrane, but is copper-deficient and gold-rich. The accreted terranes may have favoured porphyry and other styles of copper mineralisation because they possessed relatively thin continental crust compared to adjacent parts of the Andes. Crustal thickening which commenced at about 30 Ma in the Arequipa terrane coincided with a major change to polymetallic, precious metal mineralisation which commonly displays high sulfidation charcteristics.

Jan 1, 1995

By C Aldrich

In this paper, the use of topology preserving projections (Sammon maps) and neural networks are considered as a basis for the construction of multivariate statistical process control charts for a semi-autogenous grinding circuit on a gold plant. Comminution circuits are often operated in a quasi-steady state mode, where the mills tend to move rapidly from one state to another. This makes them difficult to monitor by conventional means designed for continuous steady state processes. As a first step, process data reflecting normal operating conditions are mapped with SammonÆs algorithm. Only one feature is extracted at a time and each mapping is captured by a neural network model to allow online application. Reverse neural network models are used to reconstruct the data prior to the extraction of subsequent features from the data residuals. The ensemble of neural network models can then be used for both fault detection and identification. The approach compared favourable with both linear and non-linear principal component models. It was able to detect two simulated fault conditions both with a reliability of 100 per cent, as opposed to 57.8 per cent and 95.2 per cent detected by an approach based on the use of linear principal component analysis and 84.1 per cent and 98.0 per cent detected by an approach based on non-linear principal components extracted with auto-associative neural networks.

Jan 1, 2007

By Dunstan N, Valentine C

Gas power was first used on the Sons of Gwalia mine in January 1911, when a twin-cylinder Crossley engine of 167 hp was installed to belt-drive a 112 kw 550-volt ac generator. This engine was connected with a No 8 Crossley up-draught suction gas producer, using mulga charcoal as fuel.A second Crossley engine, of 400 hp direct-coupled to a 550-volt ac generator, was installed in 1912, and operated by a down-draught wood producer.This was followed by a large Kynoch twin tandem four-cylinder engine, rated at 660 hp, sea level, with a rope drive to the crushing and treatment sections of the plant.These engines operated until January 1921, when the plant and power house were destroyed by fire. After the fire, both Kynoch and second Crossley engines were salvaged and reconditioned and they continued to give useful service for some years.

Jan 1, 1932

Although laterite ores already provide a significant proportion of the world's nickel and cobalt production it is anticipated that they will surpass sulphide ores as a source of nickel in the next century. The most recent period of greenfield nickel project construction was during the 1970s when it was notable that all of the eight new plants were based on treating laterite ores. This was because of the relatively large selection of available high grade laterite ore deposits amenable to cheap open cast mining and a paucity of high grade sulphide ore prospect alternatives. Of the three processing options for treating laterite ores: 1. smelting for the lower horizon saprolite ore, 2. ammonia; and 3. acid leach for the upper horizon limonite ore, smelting currently accounts for about 80 per cent of nickel production. In the future, as saprolite ore grades decline because of relatively high exploitation rates, the incentive to process the large untapped reserves of limonite ore will increase. The high cobalt content of limonite ore also makes it ideally suited to processing by a hydrometallurgical rather than smelting route. With only two exceptions, all saprolite smelting operations have a Class 2 nickel end product (largely ferronickel) and do not produce a cobalt by-product. As a result of technological advances, the modified ammonia leach process for limonite and transition ore as undertaken at Yabulu, now allows the production of pure nickel metal as a Class 1 product, along with significant tonnages of cobalt by-product. The mixed Ni-Co sulphide intermediate product of the pressure acid leach processing of limonite ore at Mon is converted to Class 1 nickel and cobalt metal at Fort Saskatchewan, Canada.

Jan 1, 1996

The word "optimization", refers to the search of an economic optimum, or, more precisely, to the choice of technical parameters which will define the more profitable mining project, knowing the values of the economic parameters. In fact, there is no direct way to perform this optimization, because the extremely large number of technical factors involved, from the type of working and its selectivity to the characteristics of the mill and its flexibility, makes it impossible to make a comprehensive survey of all possible projects. Beside, it would be meaningless to engage in such a task as the deposits themselves are not really known, but only estimated, with sometimes a high level of imprecision. Not to mention the numerical instability which would affect such a computation! In addition, the "best" project is not necessarily the one which strictly maximizes a given profit formula. There also exist human factors which have to be complied with, when choosing the cutoff grades for instance. Finally, there are other non-numerical factors which interfere with the choice between several projects: the shape of the bottom of a pit of the layout of the access road for instance.

Jan 1, 1986

Low tonnage quartz vein-hosted stibnite lodes are widely distributed in rocks of the Tasman Fold Belt System in eastern Queensland, with particular concentrations in the Hodgkinson - Broken River Fold Belt and to a lesser extent in the Gympie Province of the New England Fold Belt: Higher grade deposits have been worked intermittently on a small scale since 1873, resulting in the production of about 5500 tonnes of antimony ore/concentrate with an estimated grade of about 55% Sb. Future production of antimony may be as a by-product from deposits, currently being explored/mined for gold in the Hodgkinson/Mitchell River area and the Amanda Bel goldfield. Establishment of an antimony processing plant in Queensland using the Quelar Process would provide a more reliable market for small producers and could stimulate future exploration and production.

Jan 1, 1990

By H Waterer, L Zheng, T Kalinowski

The Hunter Valley Coal Chain (HVCC) consists of mining companies, rail operators, rail track owners and terminal operators, together forming the worldÆs largest coal exporting facility. In 2008, the throughput of HVCC was about 92 million tonnes, or more than ten per cent of the worldÆs total trade in coal for that year. The coal export operation generates around $15 billion in annual export income for Australia. As demand has increased significantly in recent years, and is expected to increase further in the future, efficient supply chain management is crucial. The Hunter Valley Coal Chain Coordinator Limited (HVCCC) was founded to enable integrated planning and coordination of the interests of all parties, thus improving the efficiency of the system as a whole. One of the many planning challenges faced by the HVCCC is that of annual maintenance planning. Different supply chain elements, such as trains, railway track, terminal equipment and load points, must undergo regular preventive and corrective maintenance, leading to significant reductions in system capacity (up to 15 per cent). However good alignment of the maintenance tasks can reduce their impact, and the HVCCC undertakes an annual process to ensure the impact of maintenance on the supply chain capacity is as small as possible. This is achieved in an iterative negotiation process between HVCCC and individual service providers. In the past, maintenance schedule optimisation was largely manual, which for the more than 1000 tasks involved is quite labour-intensive.In this paper the authors describe an approach developed at the University of Newcastle in partnership with the HVCCC to automate this schedule optimisation process. We will discuss our experience in applying exact (mixed integer programming) and heuristic techniques from mathematics and computer science to address the problem. This work is anticipated to lead to new decision-support tools for the HVCCCÆs capacity planning team.

Sep 26, 2011

By Coxhead B. A, Brandt B. A

The geological exploration and evaluation of coal reserves involves the appraisal of very large amounts of data. Computers afford an ideal means of handling and manipulating the data, thereby avoiding the laborious and expensive method of manually compiling the logs in full descriptive language. The Minad system of computer storage and retrieval of geological and analytical data is particularly suited to the description of cores and cuttings from exploration drill-holes. The encoded data is arranged in a 120-column computer output sheet format; descriptive geological information in a 54-column geolog and analytical information in a 64-column assaylog. The acquired data is quantitative, uniform and relatively complete and can be selectively retrieved for processing by a wide range of specialized computer programs developed for the coal mining industry. Visual retrieval of data for manual processing is facilitated by the use of simple codes and logical word abbreviations.

Jan 1, 1977

By P J. A Lever

This paper presents details of CRC MiningÆs work with waterjet assisted blasthole drilling. The objective of this work was to investigate techniques that reduce the cost and increase the productivity of blasthole drilling. The focus is on a technology that uses a high pressure waterjet to assist the conventional rotary rock cutting action of a tricone drill bit. The potential benefits of this technique are increased productivity, reduced drill bit wear and reduced hole deviation and hence improved quality of drilling. This paper describes the results of a laboratory based experimental program comparing conventional tri-cone drilling performance to the proposed waterjet assisted approach. Additionally, work has been completed looking at the more practical issues around the collection and sampling of drill cuttings and water recovery (recycling) when drilling with a waterjet. These studies have demonstrated that waterjet assisted drilling can significantly increase the rate of penetration over conventional rotary drilling. For the best-case experimental result, the relative improvement was over 40 per cent. More importantly, it is a starting point for examining alternative uses of the additional drill productivity obtained from waterjet assisted drilling. For example, increased drill productivity could be used to improve rock fragmentation by drilling a tighter blasthole pattern in the same time period. an existing drill fleet, then the drill fleet size could be reduced, or improved rock fragmentation could be achieved by drilling a tighter blasthole pattern within the same time period.

Jan 1, 2004

Information from bores in the LatTobe Valley has been accumulating for over fifty years, and the manual extraction of details has become a limiting factor in their use.Punched card equipment, installed by the State Electricity Commission for accounting purposes, was known to be available for reasonable periods, and it was suggested that this could help in the extraction of data from the voluminous records.Investigation showed that they could be substantially duplicated on cards, with consequent gains on many operations; the cards being regarded as an auxiliary to the existing records.BRIEF DESCRIPTION OF RECORDSAs a bore is drilled a continuous record of the strata is kept, together with notes on the presence of water or any unusual features which the driller may observe.When coal is struck, samples of each ten feet are usually sent for analysis.The location and surface level of each bore is fixed by surveyors, and details of dates and methods of drilling are also kept.Bores are allocated numbers, prefixed by the name of the parish within which they are drilled. Numbers are allocated in conjunction with the Department of Mines, to avoid duplication.Records of strata and analyses are kept in folders, with 100 bore numbers per folder.Standard plans are drawn, showing the locations, bore numbers and surface levels. For each bore they also show the depth and thickness of coal struck, and the total depth drilled.Cross sections are then drawn, connecting the various coal seams, which have been identified by the geologist.

Jan 1, 1960

By Owen D

A central part of mine planning is to ensure the protection of the beneficial uses of water. Integrated mining software does not generally provide tools to help the mining engineer to achieve this objective. This paper identifies some of the requirements which are desirable for such a tool and discusses how object oriented modelling can help achieve an effective design.

Jan 1, 1995

This paper presents a method for estimating the strength and stability of model coal pillars with bedding planes (weakness planes) inclination. The strength of coal relative to the angular difference between the principal stress direction and bedding planes is considered. The failure behaviour of model coal pillars containing weakness plane inclination by using servo-control Schenck Machine are shown. Uniaxial and triaxial compressive strength of coal specimens are investigated, and test results indicated that the strength of coal pillars depends on the weakness planes inclination with respect to the principal stress direction. However, it is shown that with increasing confining pressure, the effect of weakness planes inclination on the strength of the coal specimens is reduced. An empirical method is given for prediction the compressive strength of coal containing weakness planes inclination. The results of this method are compared with the experimental results and Jaeger theory. Finally, three well-known empirical strength criteria were tested against the triaxial test data for coal containing weakness planes inclination.

Jan 1, 1995

By M Roberts

The aim of this paper is to evaluate the technical feasibility of application of the electric monorail as a haulage system in hard-rock underground mining in Australia, in comparison to conventional truck haulage systems. The elements of the system being investigated include mine design and layout, installation, loading and unloading subsystems, tramming speeds, cost and productivity, automation, ground support, safety and environmental factors. Electric monorail systems are potentially more cost-effective due to a range of factors: only the one system may be needed for the transportation of workers, material and rock; and excavations for monorail haulage can be smaller and mined at much steeper gradients than for truck haulage. The smaller excavation size also reduces the need for costly ground support and û in another important measure for the health and safety of mine workers, and for energy savings û it reduces ventilation requirements. Electric monorail haulage technology is being applied in hard rock mines in South Africa and considerable benefits have been realised by the industry in that country. In Australia, mine designs for metal mines generally remain based on truck haulage and/or shaft hoisting systems. There is a tendency to apply these haulage systems to every orebody. For the industry to achieve sustained growth against a backdrop of volatile diesel prices and environmental concerns, new generation underground haulage systems are required. The monorail haulage system offers opportunities in improving materials handling efficiencies in underground mining operations. This paper examines the application of monorail haulage in metalliferous underground mining, presents comparative data with track and trackless haulage systems and develops concepts for system application in combination with conveyor belt haulage and narrow vein mining situations.

Jan 1, 2005

By Cox A

A key concern both in public perceptions of the environmental performance of the mining industry and in the development of policy relating to mining activities is the state in which the areas may be left at the completion of mining operations. There is, in effect, concern that the transient economic benefits of mining are enjoyed by the few, while the 'scars' may remain for all. While the techniques of mine rehabilitation have improved rapidly in recent years, an important set of economic issues has generally been neglected.In this paper, the economic and policy aspects of mine rehabilitation are examined. The key issue addressed is how to determine when expenditure on rehabilitation should stop. The answer to such a question requires consideration of the full range of social, as well as private, costs and benefits of rehabilitation at a particular site. Clearly these costs and benefits will vary between sites. From both an economic and policy perspective it is important to establish whether the additional gain from more rehabilitation would exceed the additional cost.It is concluded in the paper that the technical feasibility alone does not justify a paeticular level of rehabilitation activity and expenditure. While more rehabilitation at a particular site may be technically feasible, the additional expenditure incurred in undertaking that rehabilitation may result in little extra benefit. This conclusion has important implications for government policy, particularly with respect to establishing the goals for rehabilitation, criteria for successful rehabilitation and enforcement of rehabilitation objectives.

Jan 1, 1992

By M G. Aylmore

Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver complexes, and readily leaches gold ores in ammoniacal solutions, catalysed by Cu(II). It is particularly suited to carbonaceous ores where the recovery of gold by cyanide is poor. However research over the past 20 years has identified a number of issues and impediments that must be understood or overcome before an overall process can be demonstrated as practical and economic for typical oxidised gold ores. This paper reviews our current understanding of thiosulphate chemistry and mechanism of gold dissolution, and discusses the stability of thiosulphate and polythionates. It then reviews the results of leaching various gold ores that have been reported in the literature, discusses gold recovery options, and considers environmental and toxicity issues. Some of the issues that require further research include decreasing the oxidation of thiosulphate by Cu(II) or other oxidants, increasing the extraction of gold compared to cyanide, and understanding the variation in gold recovery between ores. More work is also required to minimise the effect of polythionates on gold recovery using resins or alternative absorbents, to improve the elution of copper and gold from resins, and to recycle or minimise the concentration of reagents.

Jan 1, 2002

The intent of this address is to look forward into the 21st Century and present certain thoughts as to how underground coal mining might be conducted. The views in this talk are based principally on the author's experience with mining practices in the United States. It may be difficult to accept, but the 21st Century is a mere 12 years away. What new techniques will be available? To develop an understanding of the way in which technology has been and could be changing, a two- stage analysis is made of mining technology for U.S. Coal. The first phase covers the period 1975 to the present, while the second includes 1960 to 1975. This historical perspective includes a view of underground production by mining methods, considerations of labour productivity, and a review of accident and fatality rates. Several topics are important features of this historical analysis. Among the most significant are: (1) the introduction of Ion-wall mining technology into U.S. underground coal mines, (2) the use of computers to assist in mine planning and design activities, (3) major efforts to improve health and safety performance, with emphasis on underground dust control, and (4) improvements in mining equipment with an eye towards increased reliability and up-time performance. Based on that historical perspective, projections are made in three increments. The first being immediately at the turn of the century, the second being a dozen or so years beyond that, and the third being at the quarter point of the 21st Century.

Jan 1, 1988

By Kerkhoff G, Wood J

The maximum gas emission into underground workings can be predicted by the use of established methods which have world wide recognition. Changes in gas emission and the influence of the gas and geological environments during longwall mining at Pacific Colliery, were found.to be a typical. The relationship between longwall mining and gassy conditions is found to vary from the European experience because of the different mining and geological conditions encountered, and the higher productivity achieved, by single longwall panels in Australia.

Jan 1, 1988

In underground ore mining of copper ore, lead-zinc ore, tin ore and fluorspare in German Democratic Republic geological situation is characterized by ore deposits of small thickness and great variability of ore grades and mining conditions. For long range mining strategy and short-term planning of production a model was developed fitting to make optimal economic mining decisions. Starting point of the model is a cost function representing all direct costs per unit recoverable metal in concentrate for each stoping unit (ore reserve block). In the costs function the results of regression analysis of ore grade and metal recovery in concentration plant were considered. All stoping units (ore reserve blocks) of a mine were arranged to growing direct costs. The relationships of recoverable metal, ore tonnages and corresponding costs were plotted in a diagram. The data processed by- computer and the graphic representation of the results make possible 1. economic evaluation of stopes and ore reserve blocks, 2. estimation of cut off grade, 3. optimization of works planning.

Jan 1, 1977

The process of resource estimation of large precious metal deposits is illustrated by reference to major deposits now being mined or developed by Placer.The estimation procedure commences with building an appropriate model of the mineralization and proceeds through steps of data validation and geostatistical studies. It is important that the geologists most familiar with a deposit be involved with all stages of the estimate, and also prepare a manual estimate used to validate the kriged resource.Resource estimates are major exercises taking many man-months of work. The most time consuming part of this is usually construction of an appropriate three dimensional geological model. The data base for the resource calculations must be complete and checked for accuracy. The most appropriate estimation method must be selected.

Jan 1, 1990

The impulsive loading tests under confining pressure were performed to investigate the dynamic fracture properties of rocks in a triaxial stress state. The apparatus in this study consists of the Split Hopkinson pressure bar, a pressure vessel and hydraulic actuator. Magnetite-quartzite and limestone were selected for the test. The stress-strain curves and fracture strength under confining pressure obtaind in the tests were compared with those of the conventional triaxial tests. Finally it is concluded that on the effect of dynamic that on the effect of dynamic compressive strength of rock, dynamic elastic coefficient of rock and confining pressure etc. on the blasting result

Jan 1, 1990