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Looking back 25 years, the role of the drill and blast engineer in an Australian mine seemed relatively simple, with the primary focal points being scheduling of the drill rigs, oversize control, and budget control with respect to consumption of both explosives and drill consumables. The choice of explosive selection was relatively simple, though many mines were becoming involved in trials of slurry explosives, emulsion blends, and low density ANFO blends. Guidelines to assist the engineer towards specific fragmentation targets were scarce, environmental constraints were light, and computers were rarely found on the desks of any mining engineers. Wall control blasting was in its infancy, with the bulk of attention being given to appropriate slope design and little real attention given to factors such as explosive distribution, and optimum delay timing and sequencing. Quantitative measurement of blasting performance was rare. The science of blasting, for fragmentation control, wall control, and environmental impact control was about to be born, and was heralded in those years by intense efforts by the explosive manufacturers and a proliferation of research centres throughout the world. Since the early 1980s, the role of the Australian drill and blast engineer has gone through a major metamorphosis, and currently requires a greater depth of scientific understanding than any other specialisation within mining engineering.

Jan 1, 2004

By Richmond GD

The Hellyer concentrator of Aberfoyle Limited commenced production in 1989 processing a fine grained, massive sulphide ore containing Zn, Pb, Ag, Cu and Au as values. Four concentrates are produced - copper/silver, lead, zinc and bulk (Pb/Zn) - with overall payable recoveries (1991) of 80 per cent Zn, 55 per cent Pb, 50 per cent Ag, 30 per cent Cu and ten per cent Au. Metallurgical development work commenced immediately after plant commissioning, and continues. The flotation response and liberation analysis on a size basis highlighted reagent balance problems associated with tower mill regrinding of sphalerite, poor conditioning of flotation pulps, poor selectivity for fine galena, and insufficient liberation. These were the main causes of values lost to tailings, values reporting to the 'wrong' concentrates and of impurities in the concentrates. Modifications to tower mill regrind circuit operation, and the use of improved conditioning techniques have greatly improved concentrator performance, particularly in the finer (-5 micron) size fractions. Studies of concentrator and laboratory flotation by size and liberation analysis are the basis of diagnostic metallurgy. The techniques used to evaluate the improved concentrator performance are discussed.

Jan 1, 1993

The Mt Leyshon Gold Mine is located 30 kilometres south of Charters Towers in Northern Queensland. The current open cut mine has been in operation since 1986. In 1992 a feasibility study was completed that recommended an increase in production to over 240 000 ounces of gold per year. This proposal required an upgrade of the processing plant to five million tonnes per year, and an enlarged mining fleet to provide additional ore, and to meet the increased waste removal requirements. The implementation of the mine expansion program during 1993 required the Life of Mine plan to be extensively revised. This required the assessment and management of potential risks associated with the mine design. The updated geological model using the 1992 drilling results along with the actual contract mining and processing costs were used to establish a series of nested optimised pit shells. The total and incremental quantities and costs were then analysed to determine a suitable pit perimeter. The pit and phase plans were then created and used to devise a staged development plan. The block layout plans for each bench were then established from which a detailed life of mine production schedule was created.

Jan 1, 1994

By R E. Conder

A major initial and ongoing cost component in many mining operations is that of transporting mined materials and processed ore from the point of extraction or processing to the next operation. For various reasons the transport distance can be significant or in some cases the route may be particularly challenging. The trend to higher production rates to gain economy of scale benefits and capitalise on sales opportunities means that optimisation of transport can play a significant part in profitability. Apart from the cost criteria, increasingly there are other criteria such as environmental restraints, land ownership and security of supply that can have a significant impact on determination of the optimum route and transport vehicle. The paper aims to briefly highlight the important selection criteria and the benefits and disadvantages of the most commonly utilised transport vehicles. It then moves on to looking in more depth at belt conveying, highlighting the unique capabilities of the Metso MRC Cable Belt Conveyor system.

Jan 1, 2004

By Jiang G

The Chinese Central Government attaches great importance to the development of its coal industry. Besides carrying out the policy of simultaneous development of large, medium and small coalmines,the main strategy is to gradually modernize coal mining areas and coalmines and to increase the output from individual coalfaces. There are particular implications, processes and main experiences of coalmine modernisation in China.Ensuring a coal output of over one M tonne/yr from one coalface is a very complicated system-engineering project which deals with a wide range of problems. The most important measure used for achieving an output of over one M tonne/yr from a single coalface is the analysis of affecting factors on coalface production by means of the theory c reliability. Thus, as far as possible , the production stoppages caused by mechanical equipment failures and other factors are avoided, the equipment recovery rate is increased and the working hours of shearers are extended so as to ensure a high output and high efficiency.

Jan 1, 1991

By Williams ID

Ore and coke of various size fractions (1 to 11 mm) were packed in a column (146 ó) and resistance to air flow measured under a range of conditions. Results have shown that layered charging results in an interface having essentially a directional structure the thickness of which is directly proportional to the coke and ore size ratio and whose flow resistance exceeds that of the coke layer many times its thickness. Friction factor - Reynolds number plots showed large positive departure from the Ergun equation for all components investigated whilst functional analysis and that in terms of bed constants, showed a strong dependency of the pressure gradient on bed properties and the actual particle size as well as the size ratio. It is also shown that pressure gradient in mixed beds follows previously reported behaviour and that a directional interface offers higher resistance to flow than a mixed interface having the same volumetric ore/coke ratio. Significance of results to practice is discussed.

Jan 1, 1975

A statistical investigation of folding at Mount Isa disclosed similar patterns in both the shales and the "silica dolomite" zones. Analysis of these patterns yields 3 groups of folds fully developed north plunging folds, fully developed south plunging folds, and flexuresrepresenting stages of development of folds. Interpretation of results indicates that a regional force from a southerly direction was responsible for the folding.The general pattern of shearing is allied to that of folding, with the exception of bedding-plane shearing. Many shears resulted from continued application of force on folds which ruptured after overthrusting. Other shears resulted from rupture of the more incompetent shale members, without associated folding. The shear pattern is consistent with the theory of a regional force from a southerly direction.INTRODUCTIONThe notes on folding and shearing presented in this paper are part of a current study of the structural geology of Mount Isa.FOLDING 1Measurement of FoldsInvestigation of folding underground involved the measurement of plunge, strike and dip of the axial plane, and the order of magnitude of each fold, together with its location and the rock type. The total number of folds measured was 701, of which 411 occurred in shale areas and 290 within the "silica dolomite" zones. All folds measured are located on main levels, from 7 level to 13 level inclusive. The sections of the mine involved are the Black Star, Black Rock and Racecourse. Detailed investigation of folds on the upper levels (4, 5 and 6) has not yet been done, but observations there suggest...

Jan 1, 1961

Valuers will often intuitively express the probability that property value will exceed a certain amount . . . 'I think the chances that the value will exceed $50 million are excellent. The chances that they will exceed $80 million are poor'. This paper shows how it is possible to combine the uncertainties of the value of several key items to provide an estimate of the probability of a certain overall value being achieved. The valuation of a large copper/gold deposit was naturally influenced by uncertainties in the base assumptions of costs and metal prices. Potential acquisition of the property through share purchase raised the issue of what was a reasonable intrinsic value for the shares. Market considerations could be used to appropriately adjust the intrinsic value. After a range of possible metal prices and operating costs were determined, estimates were made of their probable distributions. By combining these probabilities in a random selection, a range of property values was calculated. Each value had its respective probability of occurrence. This allowed a most likely value of shares to be calculated. This paper demonstrates how the valuer's intuition is complemented by numerical analysis.

Jan 1, 1994

An image analysis system has been built which automatically digitizes camera input of rock fragments, analyses the digitised data to determine the sizes and shapes of the rock fragments, and outputs the analysed data to a printer in the form of a histogram or a scatter chart. The high speed of such a system allows for direct collection of data from material thrown into the air by blasting, material travelling on a conveyor belt, and material free-falling on to a stock-pile or into or out of a rock-crusher. Data on the blasted, un-crushed material provides information on changes in the lithology and structure of the rock face as it is quarried or mined: flatter fragments may represent approach to a brittle, unstable shear zone, or a change from sandstone to shale; so that the informa- tion reflects the effect on the sizes and shapes of the fragments by the blasting process and/or by the rock structure. The size and shape distributions of rock fragments produced during blasting and during processing may now be continuously monitored. Such detailed analysis of the results of fragmentation is labour-intensive and expensive when the size and shape distributions are obtained manually, but is cheap and efficient when using this image analysis system. Such a system will enable the results of blasting, quarrying, mining and crushing to be cheaply analysed and correlated with current and changing indus- trial practice so leading the way to increased productivity.

Jan 1, 1988

Existing production facilities are constantly looking at ways to increase capacity. Many recent solutions have focused on the implementation of capital and infrastructure projects. It is accepted that capital expansions are frequently necessary for production gains; however, in many cases existing assets have the potential to deliver substantially better throughput than they are currently achieving. By focusing on automation of production control systems, production reporting and business processes substantial gains can be achieved utilising existing assets. This potential can be realised quickly and has been proven across several sites and industries. In the Pilbara region of Western Australia throughput gains of between two per cent and 25 per cent (translating to millions of tonnes per annum) have been achieved from existing assets using the methodologies discussed. The improvement process involves evaluating the entire production chain from the time the ore arrives at the plant to the time it is dispatched. A technical evaluation of the performance of the control system and plant automation interfaces to upstream and downstream processes is conducted. The relationship of these processes to the business systems and the human interface to the systems is reviewed to ensure a complete picture of the system is understood. Technical evaluation targets include: individual equipment operation, the engineering level of control systems, feed controls, etc; managing recirculating loads, surge capacities, dynamic inventories as well as management of in-feed systems and integration into yard and out-feed systems; and communication flow between control and other systems, data alignment between rail and shipping schedules, yard systems, sales systems and maintenance systems including such fundamentals as truck dispatch links to plant control. In parallel with the technical evaluation, business system evaluation takes place, including analysis of the operational systems, methods and personnel.

Jan 1, 2007

By Johnson D. P, Beamish B. B

The northern Bowen Basin has a very large resource of coalseam methane gas-in-place - 136 TCF(7ohnson and White, 1988). The gas is pipeline quality, being 98-99 per cent methane with traces of carbon dioxide and higher hydrocarbons. The largest resource of natural gas within the coalseams of the northern Bowen Basin is contained in the Moranbah Coal Measures (75 per cent). The next most important resource is in the combined upper Fort Cooper (16 per cent) and Rangal (nine per cent) Coal Measures. The far northern parts of the basin have low gas contents due to the combined effects of limited extent of the coal measures, shallow depth and low rank. Reserves per well are more than double that of the best coalseam methane wells in any basin in the United States. In some areas of the Moranbah Coal Measures, the gas-in-place estimates exceed 225 million cubic metres per well (80-acre spacing). A distinction is made between resource base, as determined from this basin assessment, and the deliverability potential. Parameters used to estimate gas-in-place (coal area, thickness, density, rank and depth) can be adequately extrapolated from areas of high- to low- data density. Parameters affecting methane production (permeability, gas depletion factor and critical desorption pressure) cannot be generalised. Exploration and development programs must rapidly develop a predictive capability for these factors, on a local scale, through geological modelling and confirmation drilling.

Jan 1, 1991

By O&apos, Malley G. B

The properties of bearing metals are of considerable interest to mine engineers, since continuous running of mine and mill machinery is of vital importance. Of the several available types of bearing metal, the low melting point lead or tin base alloys are most generally used in mining plant because of the ease of replacement and the possibility of remelting scrap metal from old bearings. The most valuable property of these "white metals," however, is the plasticity which gives a self-aligning character to the bearings, enablingthem to adjust themselves to inequalities which may exist at the time of fitting, or which may develop during running. The object of the present paper is to explain in general terms the physical structures of white bearing metals, and to point out that constitution rather than composition determines the physical properties of these alloys. The same, indeed, is true of most engineering alloys. In steels, for example, a change in the structure may affect the properties to a far greater extent than a change of chemical composition.Structural changes in steels are produced chiefly by heat treatment. In the case of bearing metals no good purpose is served by heat treatment; the microstructure is determined by the conditions of casting, and striking differences in constitution (and therefore in properties) are encountered in an...

Jan 1, 1932

BHP BillitonÆs Yandi channel iron deposit has a large resource of approximately 1.3 billion tonnes. This is a bulk mining operation with a high degree of selectivity not being practical. In contrast the deposit geology is a complex interrelationship of primary channel facies, secondary enrichment of iron and a secondary redistribution of the major contaminants. These variations in geology and alteration can occur over ranges of hundreds of metres down to knife edge contacts. In addition, differences in primary facies and mobility during alteration often result in the iron and contaminants having different patterns of enrichment and depletion. Despite the scale of these operations, if the geological domaining is not optimal, significant errors in the resource estimate of grades and tonnage will occur. Getting the geology right has become a common clichT among mining professionals. However, in many situations, obtaining optimal geological domains for resource modelling is best achieved when there is input from geology, statistics and geostatistics. In this paper, moving window statistics are utilised to see through locally high variability to identify trends that assist in locating difficult to identify geological boundaries. After the creation of geological domains, univariate and multivariate statistics and principal component analysis assist in validating and characterising geological domains. Finally, variography and domain contact analysis are used to analyse the nature of the boundaries between geological domains. At the Yandi channel iron deposit, the inter-relationship between geological and geostatistical analysis has resulted in significant improvements to geological domaining and the treatment of domain boundaries during estimation of iron and contaminates.

Jan 1, 2005

By J Garritsen, P F. Wells, M Xu

IncoÆs Clarabelle mill currently processes ores from eight mines in the Sudbury basin area in Ontario, Canada. The ore from the Garson mine contains a much higher concentration of arsenic than the other ores. Adding this ore into the feed to the mill has resulted in an increase in arsenic content of the Cu-Ni bulk concentrate to a level that significantly affects the smelter operation, and more importantly the efficiency of Cu-Ni separation in the Matte separation plant. The arsenic occurs mainly as gersdorffite (NiAsS), with a small amount being in the form of cobaltite (CoAsS). Extensive laboratory tests on depressing arsenic in Garson ore flotation have been conducted and two reagent suites have been identified as effective arsenic depressants. One is the so called MAA depressant which is a mixture of magnesium chloride, ammonium chloride, and ammonium hydroxide. This reagent combination was reported to depress other arsenide minerals such as arsenopyrite (FeAsS) and enargite (Cu3AsS4). However, in this study for the first time it has been shown to have a depressing effect on gersdorffite. The other reagent suite, a mixture of triethylenetetramine (TETA) and sodium sulfite, that has been reported as an effective pyrrhotite (Fe1-xS) depressant in pentlandite ((NiFe)9S8) flotation, has not been reported as gersdorffite depressant before. The effectiveness of both reagent suites is more pronounced when the arsenic minerals are oxidised through pulp aeration or the addition of hydrogen peroxide. With a flow sheet consisting of a magnetic separation, rougher- scavenger flotation, followed by regrinding and cleaning of combined magnetic and scavenger concentrate, the arsenic recovery to the final Cu-Ni bulk concentrate was reduced from 73 per cent in baseline test to less than 30 per cent with either reagent suite at no decrease in nickel recovery. The TETA/sulfite reagent combination has the advantage over the MAA suite in that pyrrhotite is also depressed, rather than being activated, and the copper and nickel concentrate grades are therefore increased.

Jan 1, 2005

By T P. Hynes

Submarine tailings disposal is conceptually an attractive option for managing reactive mine wastes in coastal regions by virtue of reduced sulfide oxidation under a water cover and no infrastructure to maintain after mine closure. However, the lack of detailed knowledge of metal leaching, dispersal of fine tailings and biological impacts in the marine environment has led to no operating permits currently in effect in Canada. Detailed chemical and ecotoxicological assessments at two historic copper mine sites (Little Bay and Tilt Cove) in the north coast of Newfoundland with tailings disposed in an estuarine to shallow (=100 m) marine environment have demonstrated reduced reactivity of sulfidic tailings when submerged under water. Only non-acute toxicity is detected in biota inhabiting the immediate vicinity (A review of another historic shallow marine tailings operation in the southern tip of Vancouver Island (Jordon River) with a high-energy setting also reveals problems with unconfined tailings dispersal and temporal biological impacts. Documented studies at two deeper (140 - 360 m) marine tailings disposal operations at the northern tip of Vancouver Island (Island Copper) and northwestern coast of British Columbia (Kitsault) again illustrate imperfect predictions of tailings re-suspension and dispersal. At these sites, bioaccumulation of tailings-derived metals appears to be minimal. There is evidence of rapid re-colonisation of the tailings surface by benthos but of different species than the original population. Integrating these observations with reported metal fluxes and biological diversity associated with submarine hydrothermal vents, the risks and benefits of deep-sea (>1 km) tailings disposal are discussed. To determine if submarine tailings disposal in deep, confined basins on the seafloor is environmentally friendly, detailed multi-disciplinary research incorporating physical, chemical, biological and toxicological components will be indispensable.

Jan 1, 2003

Portman Mining Pty Ltd very successfully operated the Ferro GullyNorth Mine in the Hamersley Province of Western Australia to satisfy a contract for the delivery of six million tonnes of iron ore in less than two years to the Mount Newman Mining Co Pty Ltd. The high-grade ore extracted from Ferro Gully North Mine was unusual in that, not only was it within the Joffre Member of the Brockman Formation, but it was rich in red ochreous hematite and martite and very low in phosphorus.

Jan 1, 2001

ICI Australia has been developing PC-based software to assist the blast engineer to design and monitor open pit blasts. The scope of this software differs significantly from commercially available mine design packages.The software is designed for routine use in a normal production environment. The system enables the engineer to produce practical documents which include: a drilling plan, a loading sheet, a hook-up diagram, an inventory of explosives and auxiliary items, and other data on the blast such as tonnages and powder factors.

Jan 1, 1992

The complexities of mining in current economic conditions, where ore extraction schedules are varied on a weekly basis so as to ensure constant supply to the process plant, can result in a number of scenarios that pose geotechnical challenges. This paper presents a case study where alterations in the mining schedule of a particular mine resulted in the necessity to mine under a large uncompacted embankment, ie integrated tailings and mine waste land form. To effectively ensure that ore recovery was maximised, a well-designed slope monitoring system to evaluate design performance and to provide timely warning of impending failures was imperative. In order for an appropriate slope monitoring strategy to be developed, a thorough understanding of the potential slope failure mechanisms, capabilities and limitations of available monitoring techniques is required. Communication of the monitoring results and response strategy to alarms generated by monitoring systems must also be carefully considered to maximise effectiveness. The results of preliminary stability modelling can be used to guide the design of a monitoring system, which in turn can then generate data which can be used to iteratively refine the geotechnical model. This paper illustrates the development and implementation of a slope monitoring system and associated communication system, using the Daydream embankment at Fortescue Metals Group's (FMG's) Cloudbreak Operations as a case study.

May 1, 2010

It is usually the case that the short-term plannerÆs role is occupied by the younger site mining engineer. ThatÆs because mine scheduling is generally seen as a mundane and thankless task. But, short-term planners play an extremely important role in maximising the value of the mining resource, generally the companyÆs biggest asset. A look at any mining operation today will expose the competing drivers behind the operational and strategic plans. Operations are too often faced with pushing short-term constraints. It is the responsibility of the short-term engineer to answer the question of æWhere to next?Æ. In answering this question the young mining engineer is in an environment overflowing with urgency and constraints. Hasty decisions made at this time may have significant adverse consequences to the long-term value of the resource. Long-term strategy must address a broad and expanding number of issues that are generally overlooked by the short-term planner. It takes a holistic, rather than the prescriptive approach of short-term planning to determine the best strategic direction for the operation. To better understand the consequences of decisions made at the operational level short-term planners need better vision of the whole business. The key to improving the mining business is a planning process that integrates the short-term planners role with the overall mining strategy. Future developments in the mine planning process will focus on bridging this ædisconnectÆ between the operational objectives and the long-term goals. Improvements will come from the tools which planning engineerÆs use, and the planning methodology surrounding them. There will be significant hardware improvements to improve the speed with which a short-term planner can evaluate plausible options. Software that maximises the use of the improved hardware will be developed. Complimenting these technological improvements, conceptual methodologies of mine planning will improve to allow strategic planning to be brought within the focus of the short-term planning engineer. In todayÆs mining industry the young mining engineer is embarking on a career where business processes are paramount. This paper discusses the ædisconnectÆ that occurs today between the operational planning and long-term strategy and how this is driving developments in mine planning today.

Jan 1, 2003

This paper deals briefly with three of the more controversial aspects of the geology of the Mount Isa ore deposits namely the geologic structures, the method of ore deposition and the origin of the ore.In the section on geologic structures, an outline is first given of the purely tectonic deformation advocated by the early authors. The current interpretation, which differs in the proposed order of events and causal forces, is then discussed. Other concepts, which attribute all or part of the deformation to sedimentary features or preconsolidation movement, are outlined ilnd commented on.The remaining two sections deal mainly with the better known lead-zinc orebodies. In the first of these a brief description and criticism is given of the early interpretation which was based on the deposition of successive waves of mineralisation which replacedindividual beds in the shales. The current ideas, which visualise emplacement of the ore between the beds rather than replacement of them, is then discussed. The final section develops the case for a sedimentary origin of the lead-zinc ores and broadly outlines the author's ideas concerning the evolution of the Mount Isa ore deposits.INTRODUCTIONAny consideration of the geology of Mount Isa must begin with the work of Blanchard and continue with that of Hall. Individually, or as co-authors, they published various papers on the geology of Mount Isa. Of these, the best known is their "Rock Deformation and Mineralisation at Mount Isa" (1941) which gave a comprehensive account of all aspects of Mount Isa geology.It is necessary to appreciate the limits set on geological knowledge of the mine and environs in 1941 by the extent of mine development and regional geologic studies. Underground, 7 level (897 ft.) was the lowest producing level. Development on 8 (1073 ft.) and 9 (1247 ft.) levels consisted only of exploratory drives and crosscuts in the vicinity of the Davidson Shaft. The tops of the 650 and 750...

Jan 1, 1961