Search Documents

By H S. Pescini

A material aim when feeding ore blends into a processing facility is to reduce the variability of the properties of the feed material and to maximise the output, or throughput. At the Mining Geology conference of 2019, we presented a paper on optimal blending of coking coal given geological variability. The paper introduced integer-programming techniques to both maximise value and minimise feed or product variability. We discussed an application where the geological uncertainty is characterised using a normal distribution and exact solutions are readily obtainable using second order conic constraints in the mathematical model. Geological uncertainty is not always normally distributed, many properties will be characterised as log normal or some other skewed distribution. For example, copper can be some form of lognormal and Fe in Iron ore has a left skewed distribution. In this paper, we discuss some distribution free techniques to optimise the blends of plant feed or output given a quantified geological uncertainty. We discuss the sample average approximation method and how to set-up and apply the method to an ore blending problem. Evaluating a case study demonstrates that the explicit use of non-normally distributed geological uncertainty can better optimise feed into an ore processing facility and potentially add significant value. The approach is equally applicable to all mining and processing operations that blend material into a processing facility or directly into a saleable product.

Mar 22, 2022

By P Grieve, J L. Mauk

The Central Maratoto Valley in the Coromandel Peninsula contains a sequence of veins in pervasively altered dacite + andesites of the Waipupu Formation. We recognise at least eight different vein types: (1) pyrite stringers, (2) quartz + carbonate veins, (3) crystalline quartz veins, (4) carbonate veins, (5) chlorite + carbonate veins, (6) siderite veinlets, (7) siderite + carbonate veins and (8) carbonate + pyrite veins. The overall temporal trend of the veins is from early pyrite to quartz and then to late carbonate veins. Carbonate veins and pyrite stringers both form planar and irregular veins, whereas some carbonate veins have diffuse contacts with the wall rock. Gold and base metal sulphides are associated with some of the quartz + carbonate veins. Textures within the veins reflect open space filling and multi-phase reopening. A partial record of hydrothermal activity has been preserved by vein crosscutting relationships, hydrothermal alteration minerals and fluid inclusions. Hydrothermal alteration minerals display zonation from south to north. The alteration increases from unaltered to weak propylitic alteration of andesite in the south (MVRCDC1), to sericitic alteration of andesite and dacite in the north (MVRCDC3). The alteration assemblage is dominantly sericitic, with no adularia present, drawing parallels to the Thames region where there is no adularia.

Jan 1, 1999

By Gordon DM

SUMMARY Tyres account for 25-30% of the operating costs of large capacity haul units as used in open-cut mines. Tyre operating costs can be substanti- ally reduced and often contained in real terms by applying knowledge that is now available. This paper describes certain specific advances in tyre management, namely batching, bias adjustment, cumulative plotting and the so-called "pressure-temperature" system of tyre pressure control, originated on the Mt. Newman Mining Company's Newman minesite, and discusses the contribution that each has made to improving tyre management and reducing costs. INTRODUCTION Tyres are a significant cost in mining. Tyre costs make up between 25% and 30% of the operating costs of large (i.e. 100 tonne and larger capacity) open-cut mine haultrucks. On a large mine this tyre cost may amount to several millions of dollars each year. It is a fact that through careful

Jan 1, 1982

By I Mason, G Turner, J Hargreaves

One of the key objectives in production from any mine is the minimisation of ore loss and dilution. This can only be achieved when the distribution of ore within the mine is known. The distribution of ore is usually evaluated from a combination of drill hole information and underground mapping data. Three-dimensional models of the ore distribution are then constructed by interpolating grades, contact locations and confirming these estimates through mapping. While the interpolation procedure can incorporate an understanding of the local geological conditions, it is an approximation and thus susceptible to some degree of ore loss or dilution. Naturally, such problems increase in areas of sparse geologic information or greater geologic complexity. Borehole radar offers an approach to decrease the interpolative aspects of modelling by providing a continuous image of some ore contacts. Borehole radar works by building a two-dimensional image of an ore contact from radio waves bounced off the contact from closely spaced positions along a borehole. This image can be imported into Datamine (or a similar design package) and incorporated into geological models of a given ore block. The results of a trial survey from the Mariners nickel mine at Kambalda are presented to illustrate the improved level of detail and accuracy that can be achieved through the incorporation of borehole radar into orebody delineation practice. Once implemented on a large-scale this technique has the potential to greatly increase the cost-effectiveness of long hole stoping at Kambalda, through increased ore recovery and reduced dilution.

Jan 1, 2000

By D B, M A. Sares, D W. Coulter, D C. Peters

This presentation discusses NASA-funded research on the ability of hyperspectral remote sensing to map diagnostic acid rock drainage (ARD) mineralogy that adversely affects water quality within watershed and to determine the relative contributions of natural ARD sources of metals and acidity to that drainage. Ground-based reflectance spectroscopy, combined with water chemistry, is used to identify mineralogical and chemical variations throughout a watershed. Integrated with hyperspectral data acquired from airborne remote sensing platforms, such as the NASA Airborne Visible Infrared Imaging Spectrometer (AVIRIS) sensor, a methodology has been developed that should improve environmental assessments and tracking of impacts on and from drainages. Phase I of this project focuses on a drainage basin (Lake Creek), tributary to the upper Arkansas River in central Colorado, which is impacted by natural acid rock drainage from areas of high-sulfide hydrothermal alteration. This project builds upon research and inventory efforts by the Colorado Geological Survey (CGS) to identify hydrothermal alteration that is the primary source or is contributing to acidic and toxic drainage in Colorado. This presentation will cover ground and airborne hyperspectral remote sensing techniques and results and water analyses for seasonal high-flow and low-flow conditions in Lake Creek. Identifying correlations between mineralogy, especially mineralogy that can be identified through airborne remote sensing, and water chemistry is a key focus of this project. Of particular interest are low-pH iron phases such as jarosite, ferrihydrite, schwertmannite, copiapite, and transitional amorphous phases as well as AlOH phases from higher, although still acidic, pH environments which are observed to mix with the iron precipitates within the streams draining from the hydrothermal systems. Drainage in the Lake Creek watershed derives from the Grizzly Peak caldera (Oligocene), which exhibits extensive hydrothermal alteration. Alteration types include silicic, quartz-sericite, quartz-sericite-pyrite, advanced argillic, and argillic. By understanding the chemistry of a naturally impacted drainage and its relationship to the surrounding geology, the project goal is to allow more efficient and complete identification of such sources in mineralised terranes through remote sensing technology.

Jan 1, 2003

By D Semini, B Newcombe

Base-metal sulfide refractory gold ores often contain a portion of ‘free’ gold that is amenable to recovery using gravity concentration methods, whilst the refractory portion of the gold is better recovered using flotation. The decision as to whether a plant treating a refractory gold ore should utilise gravity concentration or a flash flotation circuit (or a combination of both) within the grinding circuit is usually made at the design stage of flow sheet development. Very limited data is available in the published literature which provides an industrial scale comparison on which to base such a decision and conventional laboratory testing methods are often the only way of obtaining such data. The optimum processing route will also be mineralogy dependent.This paper presents the findings of operating a refractory gold plant with either flash flotation (normal operation) or a combination of flash and gravity recovery methods treating the cyclone underflow stream and will demonstrate the regions of the recovery profile that each contributes to. Size-by-assay analysis has been performed on a number of streams around the operating plant to gain an insight into the changes that occur when the gravity circuit is in operation in addition to the flash flotation circuit. A discussion around the implications to overall plant operation in combining the use of a batch process (gravity concentration) with a continuous process (flotation) is presented.CITATION:Newcombe, B and Semini, D, 2014. Interactions between flash flotation and gravity concentration – an industrial case study of a refractory gold concentrator, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 427–436 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

All companies and individuals who embark on a business venture incur costs. For the most part these costs can be conveniently categorised, firstly into capital and operating costs and then into the various elements of these major cost centres. Although the nature of expenditure naturally differs as between industries certain broad cost types are characteristic of all heavy industries. The capital costs of gaining access to an orebody, equipping a new mine, building a treatment plant and perhaps refining and smelting facilities are likened to capital expenditure by a manufacturer on new plant and equipment required for an expansion or new product innovation. Similarly the day to day costs of labour and materials employed in the running of a mining operation can be likened to similar costs in other heavy industry. There is another group of costs that are not so easily categorised. Most industries incur unavoidable costs that do not form part of the direct or capital costs of physical production. These costs include taxes and other payments to government and research expenditure. The mining industry has a particularly heavy burden of non-production costs and it is the objective here to highlight and analyse a few of them. These costs are exploration expenditure, infrastructure expenditure, royalties and income tax. This is not to suggest that these are the only major non-production costs that the mining industry needs to bear. The industry may incur significant costs for environment protection, land tenure maintenance and on liaising with Government on a wide variety of matters. It is for reasons of subject manageability that the list is confined to the four costs mentioned. For the mining industry, exploration and infrastructure expenditure, royalties and income tax have several distinguishing features. Firstly, they are generally proportionately large costs. Exploration and infrastructure expenditure for example, could well exceed mine development costs. Depending on how royalties are levied, they may be very high in relation to profits earned and many in fact exceed profits. Secondly, except for income tax, they are costs that are generally not payable by other industries. Exploration expenditure is in some respects comparable with industrial research and development. However, because mines are wasting assets exploration is necessary for survival, and it is likely to form a larger part of costs per dollar of profits or sales than R&D. It can therefore be said that exploration is of far more significance to the miner than R&D is to the typical industrial company. Furthermore, unlike exploration expenditure, R&D results are transportable and patents permitting, transferable. The infrastructure burden that miners must carry is unique to the industry. Whereas urbanised industry is not usually liable for the capital cost of power, water, transport, townships and community facilities, the miner must finance these projects himself. Neither the payment of royalties, nor of course, income tax are unique to the mining industry. Royalties are more properly described as a unique charge on some primary industries but however described, they are a charge that manufacturing and service industries do not have to pay. Whilst we all pay income tax, the mining industry's uniqueness derives from the special problem that the industry has in arriving at annual net income in view of the capital intensity of the industry, partly due to expenditure on infrastructure, the indefinite life of capital equipment and its unpredictable residual value, funds expended on exploration and long lead times associated with a mine development. The third distinguishing feature of these costs is that, with the possible exception of exploration expenditure, they are heavily influenced by the policies and actions of Government. As such the industry has a responsibility to promote the industry by emphasising its potential to improve national product including exports and by requesting that the Government provide for the industry in its long term planning and seek its co-operation to prevent the industry incurring inequitable penalties relative to other industries.Finally, exploration and infrastructure expenditure are significant because they are front-end charges on a project. When due allowance is given the time value of money and the deferment of income from a mining development to which they relate, exploration and infrastructure expenditure assume greater importance than the raw money expenditure suggests. For all these reasons, exploration and infrastructure expenditure, mining royalties and mining income tax are worthy of detailed study. This is the purpose of this paper. The objective is to examine the determinants that give rise to them and provide some thoughts on their impact on on-going and potential mining developments and, where relevant, to make some suggestions as to how they may be minimised.

Jan 1, 1977

By Sullivan T. D, Lohe E. M

Geological structure is one of the main controls on ground conditions within mining. It has a significant impact on the mining conditions and productivity of coal mines within the Sydney - Bowen Basin. The three main types of faults common to this region, normal, reverse and strike-slip systems, each present distinct challenges to mining. These systems effect a wide range of geotechnical and mining conditions within the mines. These include coal quality, strata stability, goat and caving behaviour, productivity and maintenance schedules of mining equipment, mine design and mine-site stress fields. A better understanding of the regional, local and mine-scale structural setting, timing relationships of structural events and the mechanisms of fault formation will greatly aid industry's push for greater productivity and competitiveness.

Jan 1, 1991

By Aspinall T. O, Bell L. C

Increased awareness and stricter enforcement of regulatory requirements for adequate rehabilitation of surface mining sites has made environmental planning an essential part of strip mine planning. Rehabilitation is site specific and should be based on data which relate to that site. Cost-effective spoil pile design to minimise erosion is an important part of rehabilitation. Spoil pile design is an integral part of strip mine design. QCT Resources Limited has provided a postgraduate scholarship toward research in this area. The controlling factors of spoil pile design are post-mining land use, drainage requirements and degree and rate of erosion. The extent to which mine design is controlled by these factors is determined by regulatory requirements. To plan acceptable rehabilitation programs, erosion processes must be accurately modelled, and a range of erosion prediction models are available. Useful prediction models can be placed in two categories with the first category containing soil loss prediction models which can be used to predict the amount of soil lost from an area over a short or long term basis. Models in this category include the Universal Soil Loss Equation (USLE), Water Erosion Prediction Project (WEPP), Griffith University Erosion and Sedimentation System (GUESS) and Chemical, Runoff and Erosion from Agricultural Management Systems (CREAMS). The second category contains topographic evolution models which give an indication of the long term morphological development of a formed surface subjected to erosion processes. Models in this category include "Topog", Willgoose's Physically Based Catchment Evolution Model and Areal Nonpoint Source Watershed Environment Response Simulation (ANSWERS). The USLE has been used in the agricultural field for soil loss prediction. To apply the equation to mine sites in Central Queensland, it is necessary to understand the factors affecting erosion at the sites. This understanding should allow the variables of the equation to be quantified. The rainfall factor applied in the USLE is independent of engineering design or soil management techniques. The factor of spoil erodibility is dependent on the material's physical and chemical properties and can vary from site to site. In the equation, the topographic factor, cover and management factor and conservation practices factor can be varied by design to reduce erosion on rehabilitated areas.

Jan 1, 1991

By R G Warren

Most orebodies have cross-sections of less than 1 km2 and hence do not offer a particularly large target for exploration. Fortunately, although in the geological record ore deposits are small and rare and result from the exceptional coincidence of certain geological processes, these processes are mappable on a much larger, district to regional scale and constitute a mineral system in which the ore deposit is the central feature. A mineral system can therefore be defined as `all geological factors that control the generation and preservation of mineral deposits, and stress the processes that are involved in mobilising ore components from a source, transporting and accumulating them in more concentrated fonn and then preserving them throughout the subsequent geological history'. The mineral system concept emphasises that for many ore deposit types, although economically viable mineralisation may only occur on a scale of say, hundreds of metres, the total system of fluid-rock interactions that led to ore formation can extend over a distance of tens to hundreds of kilometres around the deposit. When mapped out, the total mineral system provides a far larger exploration target than the actual ore deposit itself. Important geological factors defining the characteristics of any mineralising system include: 1. sources of the mineralising fluids and transporting ligands; 2. sources of the metals and other ore components; 3. migration pathway; 4. thermal gradient; 5. energy source; 6. a mechanical and structural focusing mechanism at the trap site; 7. chemical and/or physical traps for ore precipitation. Many of these factors individually are common throughout time and space and are mappable on a regional scale. The delineation and empirical prediction of mineral systems can thus be approached by combining two components of metallogenic research. Firstly, the development of maps of regional geoscientific data and data sets of the distribution of factors significant for mineral systems in general. Secondly, the determination of the essential ingredients of particular styles or types of deposits in terms of mappable elements that any exploration program could focus on.

Jan 1, 1994

By Osborne V. J, Urbank W

An explosion occurred at Moura No. 4 underground coal mine in Queensland on 16 July 1986 and resulted in the loss of 12 lives. The official report of the accident concluded that the most likely source of ignition was the flame safety lamp. This paper describes an investigation of the behaviour of a flame safety lamp, similar to the one involved in the Moura explosion in atmospheres of methane, coal dust and air, carried out at the Queensland Department of Mines . Testing and Research Station. The behaviour of the lamp is described in conditions of varying methane and coal dust concentrations in air, and varying air velocity. Particular emphasis is given to the 'phenomenon of burning which occurs inside the gauze and which is capable of causing the ignition of an external explosive atmosphere.

Jan 1, 1988

The disasters between 1920 and 1979 in coal mines in Queensland and New South Wales due to underground fire, gas or coal dust explosion or to gas or coal outbursts, have been assessed. The evidence relating to disasters caused by gas explosion points strongly to divergence from safe mining practice as the main cause. There is a need for greater training and education of personnel, closer analysis of gas reports, better monitoring and testing procedures, improved ventilation standards and a policy where safe working practice is actively encouraged. Conditions in the New South Wales occurrences of gas explosion were similar to those at Collinsville, Queensland in that dykes, igneous sills, burnt out coal and faulting were common to all. Information on outbursts indicates that contributing factors were intrusions, depth of cover, fault zones and other geological disturbances, methods of work, pressure and type of gas.

Jan 1, 1982

By D S. Collins, Z Hosseini, I Pinnock, Y Toya

Microseismic monitoring is regularly used in the mining and geotechnical industries to provide detailed information about rock mass response to operational activities. This paper implements a variable 3D velocity model (VM) at a North American hard rock mine with the aim of further improving the accuracy of seismic event locations. A collapsing method is also used to help analyse two individual seismic event clusters at another North American hard rock mine. In the first case study, the location accuracy of events is shown to improve by moving from a conventional single VM to a variable 3D VM that accounts for voids and different geological domains. The modal average for the event location accuracy improved from 14 m to 5 m when the 3D VM was used. Additionally, the single VM failed to locate 26 per cent of the seismic events that were located by the 3D VM. In the second case study, the distribution of seismic events was further enhanced by using a collapsing method that highlighted planar structures. The collapsing method was performed on two large event sequences that occurred in close proximity and identified different seismic event distributions. One aftershock sequence aligned along a plane, suggesting an activated structure, while the other large event sequence had a more 3D distribution of events, suggesting a complex stress redistribution on smaller structures.CITATION:Pinnock, I, Collins, D S, Toya, Y and Hosseini, Z, 2016. Large event sequence analysis and 3D velocity models for seismic event location accuracy, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 879–884 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Competitive commercial circumstances internationally provide a prime impetus for miners to seek new technologies as a means to profitability and survival. Engineering and project management activities play a vital role in establishing, operating and developing the capital facilities used by miners. Computer based technologies are the single most important technology for maintain- ing competitiveness in engineering and project management into the future. Current applications of computers in engineering design and drafting are finding economic applications, computer-aids are more readily introduced, accepted and profitable. Computing technology is advancing very rapidly and on a broad front in hardware, software and communications. This technology advance is improving the ability of engineers and project managers to provide a high quality, responsive and low cost service which will improve in parallel with computer technology. As this technology advances, a key challenge is created for managers in selecting hardware and software, in developing people and organisations and in marketing the technology to advantage. While the future holds many exciting developments, people will still hold the key roles. While the nature of their roles may change, the final acceptance or rejection of technology will be by people, whether as users or owners, who will judge on the basis of whether their stake is improved or not.

Jan 1, 1986

By Prosser A. P

A computer simulation is being developed for in-situ leaching of unbroken, Zn-Pb-Ag sulphide ore. Ferric chloride is the selected reagent. Experimental work showed that a diffusion control model of the kinetic aspects was better than a surface chemical reaction control model. Entrapped reactive grains were accessible to reagent in the samples tested. Precipitated sulphur did not seriously hinder the reaction.

Jan 1, 1987

The expansion of hydrometallurgical operations, declining ore grades and upwardly spiralling production increases the demand for fresh and recycled water with low levels of contaminants. The minerals industry is also increasingly being forced both by regulatory and cost pressures to reduce the amount of liquid waste they produce. This requires a strong focus on waste reduction by recycling, regeneration and reuse. However, these measures are often not enough in arid countries for a forward progress and expansion of their mining activities.   It is often the case that in the arid and semi-arid countries the only available water is either sea water or underground (brackish to hypersaline) saline waters. Brackish waters can be desalted at a reasonable cost but the desalination of highly saline waters is challenging and expensive.   There are emerging reports that sea water and in some cases hypersaline underground waters are now used by various mining industries as process water. This study explores the possibility of the use of sea water in various mineral processing and hydrometallurgical processes and briefly discusses the benefits and problems related to the use of saline waters at the mine and mill site. Several cases studies and preliminary laboratory test results are presented.

Jun 1, 2010

The Tertiary gold deposits of the Hauraki area are predominantly epithermal vein types containing mineral assemblages of quartz, calcite, pyrite, sphalerite, galena, chalcopyrite, acanthite and native gold (electrum). Sulphosalt, telluride (eg hessite), seleniferous sulphide and selenide minerals are important locally. Studies of wall rock alteration mineralogy, fluid inclusions in gangue minerals, and sulphur isotopes of sulphide minerals indicate that the ore forming fluids had the following parameters: pH, near neutral at depth but acidic near surface; temperature, predominantly 320 - 270¦C for base metal dominated assemblages, 280 - 200¦C for precious metal dominated assemblages and generally below 200¦C for late stage barite; apparent salinity, six to zero equivalent weight per cent NaCl; and CO2 concentration, generally around one mole per cent CO2. There is fluid inclusion evidence for boiling during mineralisation in some deposits. Moderate values off S2 and FO2 are indicated for base metal and mixed base metal û precious metal assemblages of most deposits by the predominance of pyrite + chalcopyrite over other iron-bearing phases; primary bornite is absent, whereas pyrrhotite, hematite and magnetite rarely occur in the veins. The largest gold û silver deposits formed from solutions in which the sulphur species in solution were predominantly reduced. Near surface environments and some deep, predominantly base metal, deposits were formed from solutions with approximately equal concentrations of oxidised and reduced sulphur species.

Jan 1, 1984

A numerical method for discriminating between replacement and sedimentary processes is applied to a folded stratiform sulphide occurrence. It is shown that numerical treatment of chemical analyses from a single diamond drill hole allowed a rapid assignment of the ore to the syngenetic sedimentary class and thereby enabled a revision of the evaluation program concerned with consequent reduction in costs.

Jan 1, 1973

The effect of conditioning energy input on the metallurgical results of an emulsion flotation process has beenattributed by previous authors to a detergency process.This paper shows that such a process does not explain the data and that an attrition mechanism is more appropriate.

Jan 1, 1970

By C A. Foss, K Blay, K Leslie, D Hillan

Magnetic field studies provide remote sensing of magnetisation distributions and a means to investigate moderately- to strongly-magnetised ore deposits that may be partially or totally buried. However, above-surface magnetic field surveys have limited capability to resolve the detail of magnetisation distributions because of the large separation between the magnetisation and the magnetic sensor. While some of this detail is available from magnetic susceptibility logging within boreholes or from magnetisation studies on recovered core, these measurements are limited to the exact trace of the boreholes. The large disconnect between ground or aeromagnetic surveys and highly-localised borehole sampling can cause problems in developing robust source models from magnetic survey data. The measurement of magnetic field in boreholes has the capacity to at least partially bridge that gap by measuring the magnetic field due to magnetisations proximal to, but not intersected by, the boreholes.CSIRO has developed the world’s first downhole magnetic tensor gradiometer. This instrument measures magnetic field gradients in all directions within a borehole. A prototype instrument has been built and tested as part of phase 1 of the Deep Exploration Technologies Cooperative Research Centre (DET CRC). The prototype performed well with magnetic pyrrhotite at the DET CRC test site in the Adelaide Hills and at Carpentaria’s Hawsons magnetite deposit south of Broken Hill. Further work is required to reduce the diameter of the probe so that it can operate in NQ holes (it is currently limited to HQ or wider) and to transform it to a continuous logging tool. The borehole tensor gradiometer can be used to investigate the continuity of magnetisation over a distance of several metres to tens of metres away from a borehole intersection and the structural dip of the magnetic body. It can be used to either replace or augment downhole magnetic susceptibility logging. This instrument is one component of an integrated CSIRO suite of new magnetic field utilities and methodologies for iron ore exploration and development.CITATION:Leslie, K, Foss, C A, Hillan, D and Blay, K, 2015. A downhole magnetic tensor gradiometer for developing robust magnetisation models from magnetic anomalies, in Proceedings Iron Ore 2015, pp 299–304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015