Search Documents

Recognition is the most important aspect in the use of breccias as an exploration tool. Ore-hosting breccias occur in a wide variety of environ-ments, shapes, compositions and characteristics, but generally present favorable loci for the deposition of ore mineralization in epithermal, porphyry copper-gold-molybdenum, massive sulfide, carbonate-hosted, sedimentary lead-zinc deposits and others.

Jan 1, 1990

By D C. Curry, M F. Young

Many flotation operations need to improve liberation to increase recovery, yet often plant operators are concerned that finer grinding will produce æslimesÆ with low flotation recovery. Yet simple circuits can be designed to give good liberation and excellent fines recovery. The economics of fine grinding has changed fundamentally with new stirred milling processes like the IsaMill. This has also transformed flotation design due to the clean surfaces produced in the inert grinding environment and the narrow size distribution produced by the IsaMill. Past poor experiences with æovergrindingÆ in flotation circuits was often due to the wide size distribution and the degradation of mineral surfaces produced by conventional devices using steel media, like ball mills and tower mills. The correct practice is to design both grinding and flotation together to suit the liberation characteristics of the ore. This may result in several stages of grinding and flotation, recovering mineral as soon as it is liberated, then applying further grinding energy only to those particles that still need liberation. Flotation then occurs in relatively narrow size bands and with minerals with similar liberation characteristics. Though the circuit may look more complex on paper, in reality it is far simpler to operate since each section performs predicably. Circuit design also needs to address materials handling. Finer particles affect froth handling and dewatering, but can still be easily handled by standard products with careful attention to design of launders, pumps and pumpboxes, and de-aeration before thickening and filtering. Excellent examples of designing circuits to include ultrafine grinding include Mt Isa and McArthur River (MRM). In the last decade these operations have produced over ten million tonnes of concentrate with an average grain size below 10 ¦m and above 80 per cent recovery. At Mt Isa, zinc recovery was increased by ten per cent by applying fine grinding to existing poorly liberated streams. In fact, grinding finer in the IsaMill actually improved the recovery of fine particles by ten per cent, and maximum particle flotation recovery occurs for 10 ¦m particles. A more recent example is the flotation of Platinum Group Metals (PGMs). The use of conventional ball or tower milling to improve liberation is severely limited by the impact of commonly associated chromite on classification, and degradation of flotation performance by the steel grinding environment. The ability of open circuit IsaMills to deliver a narrowly sized ultrafine product with clean mineral surfaces is transforming the design of platinum flotation circuits. The science and practice of fine-grained flotation is now thoroughly proven. The availability of the 2.6 MW IsaMill has made ultra fine grinding a practical tool for flotation plant design. It is expected to become a standard choice for future applications of both fine-grained ores and for minerals with difficult flotation characteristics.

Jan 1, 2005

THOSE who have had occ.asion to sample a mine not infrequently find that it is impossible to take their sample cuts at regular distances apart, owing to the ground being close timbered, a stope having been taken out, or some other cause. When such is the case a tedious calculation becomes necessary in order to obtain an accurate result. A conscientious man will make the tedious calculation, but one who is inclined to be lazy, or who does not recognize the importance of accuracy, or has not the time, may be satisfied with either the arithmetical or weighted arithmetical mean result.There are two main systems of taking samples when the cuts are taken-(l) at equal distances, (2) at unequal distances. When the samples are out at equal distances apart there are three methods of computing the assay value :-1 (a) By Arithmetical Mean. The sum of the values and sum of the widths are each divided by the total number of samples, in order to obtain the value and width respectively, no allowance being made for the relative widths arid values. The result isabsolutely inaccurate, and should never be used under any circumstances.1 (b) By Geometrical Mean. The assay widths ie, feet %, feet oz, inch dwt, &c, are added together and the sum of these is divided by the sum of the widths.

Jan 1, 1911

By D R. Swinbourne, Y H. Yang

Calcium ferrite slag has gained prominence in the copper smelting industry over the last decade due to the emergence of continuous converting as an established technology. As smelters move towards processing which is higher in intensity, more efficient and more environmentally acceptable, its use is likely to increase because it has technical advantages over conventional iron silicate slag, which include a higher magnetite-holding capacity, lower copper losses to slag and a lower viscosity. Calcium ferrite is currently the converting slag of choice in the Mitsubishi process at operations in Japan, South Korea, Indonesia, Canada and Australia, and in the Kennecott/Outokumpu flash converting process in USA. However, users of this slag have experienced problems in containment due to its highly corrosive nature and low viscosity. As use of this slag becomes more widespread the containment problem will assume greater importance. Consequently, work has recently been carried out to establish the mechanism of refractory attack and devise means to retard it. This work will be critically reviewed in this paper.

Jan 1, 2000

By V Glenn, P McKenna, H Vickers, P Audet, M J. Gillespie, A Gravina, D R. Mulligan

A requisite corollary of mineral sand mining on North Stradbroake Island (Queensland (Qld), Australia) has been the progressive rehabilitation of post-mined lands for the revegetation of native subtropical Eucalypt communities. Since 2005, rigorous environmental monitoring has been undertaken to verify the annual development of post-rehabilitated sites. From these long-term analyses, a chronosequence of land revegetation (ranging from three to 26 years postrehabilitation) was developed to examine the rehabilitation trajectories of various post-mined sites in relation to proximal undisturbed locations. Here, we identified that some sites may be deviating from the intended natural analogues as evidenced by the opportunistic colonisationand otherwise æinvasiveÆ behaviour of a regionally native species (Black Sheoak - Allocasuarina littoralis), which appear to be displacing the intended Eucalypt varieties. Although it is recognised that the broader data trends correspond to distinct periods of adaptive modifications to the implementation of rehabilitation (ie pre- and post-1995), this analysis focuses on further identifying potential above- and belowground feedback mechanisms underlying these divergent ecological outcomes.CITATION:Audet, P, Gravina, A, Glenn, V, McKenna, P, Vickers, H, Gillespie, M J and Mulligan, D R, 2012. Above/belowground feedback may facilitate and sustain mono-dominance on rehabilitated North Stradbroke Island, in Proceedings Life-of-Mine 2012 , pp 15-24 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Shuqing L

The application of single liquid cement for fracture grouting in base rock may have history more than 120 years. The disadvantage of it is difficult to increase the grouting efficiency, because the jelling time of it is very long and hard to control. The double liquid grout, such as chemical grouts and cement water glass grout was developed at the end of 1960.'s Although the jelling time of this kind of grout can be controlled, it mast adopt double liquid grouting technology, use complicated equipment and is not easy to control component's ratio of the grout. Another disadvantage for chemical grout is high price, and have pollution to environment. OCE series single liquid grout is the effective grout material developed recently by making large efforts in Ohina. Main feature of it is that the jelling time is easy to control, materials from cement and clay are very cheap and without pollution to environment, and the grout can be injected by single liquid technology. The effect of QCE series grout has been proven by its application in China. It can be believed that QCE grout has great economic efficiency and will give a push to develop grout material.

Jan 1, 1988

By Thompson P, Sharma Y

The paper describes the methodology and results from a study carried out by Telfer Gold Mine to optimise the materials and costs involved in construction of the pad for their dump leach operations. The investigation involved large-scale field testing of five different types of liner and a number of different cushion and drainage layer configurations. The aim was to identify the most cost effective construction methods to allow the final dump height to be increased from 45 in to 60 in without causing significant damage to the liner. The effects of dump height on permeability were also investigated. These methods are described and results presented. The findings indicated that modifications to the existing liner/cushion layer/drainage layer configuration used previously at Telfer would actually reduce overall construction costs rather than increase them despite an increase in overall dump height. Relative construction costs are presented.

Jan 1, 1994

By B Banerjee, H Masoumi, X Shen, S Raval, D Tannant

Structural mapping of pit walls can be performed using digital images and photogrammetry software, but the performance is limited by weather and environmental conditions including dust, rain and light. On the other hand, active sensors such as terrestrial laser scanners (TLS) and total stations (TS) suffer from vertical orientation bias and occlusions when persistent discontinuities dip at the same angle as the scanner line-ofsight. The recent development of the compact light detection and ranging (LiDAR) systems has made it possible to mount these sensors on unmanned aerial vehicles (UAVs) or drones which offer the potential to overcome limitations that are inherent in existing mapping systems. This study details the research involving integration and application of an advanced UAV-LiDAR system for structural mapping of a highwall. A state-of-the art laser scanner with an inertial measurement unit (IMU) and real-time kinematic global positioning system (GPS) was integrated on to a UAV. The system was first tested in a laboratory condition. Then the UAV-LiDAR system was employed to map a highwall of a coal mine. The planned flight trajectories tested the system at variable distances from the highwall face and at various speeds. The raw data collected from individual sensors were fused, filtered to remove noise, and segmented to produce a surface scan model. Finally, the point density and surface coverage were measured using the surface scan model of the highwall. The parameters were compared with equivalent measurements computed from a reference TLS data. The study demonstrates the capabilities of a UAV-LiDAR system to generate accurate and occlusion free data for mapping highwall geological structure with very quick and efficient flights in the field. CITATION:Raval, S, Banerjee, B, Shen, X, Masoumi, H and Tannant, D, 2018. Evaluation of a UAV-LiDAR system for mapping geological structures in an open pit highwall, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 496–503 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By C R. Stanley, D Lawie

The measurement of error in assays collected as part of a mineral exploration program or mining operation, including errors introduced during sampling, sample preparation, or geochemical analysis, historically has been undertaken in a variety of ways. Different parameters have been used to describe the magnitude of relative error and each of these parameters is related to the standard measure of relative error, the coefficient of variation. Calculation of the coefficient of variation can be undertaken in a variety of ways; however, only one produces unbiased estimates of measurement error: the root mean square coefficient of variation calculated from the individual coefficients of variation. CITATION:Lawie, D and Stanley, C R, 2012. Average relative error in geochemical determinations - Clarification, calculation and a plea for consistency, in Proceedings Sampling 2012 , pp 181-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

Ore petrology will fundamentally determine the types of metallurgical processes employed for ore treatment, their operational efficiency and the nature of processing problems encountered. It is therefore paramount that the petrological charact

Jan 1, 1998

By V A. Diemar

The Chatree Gold Project represents a greenfields discovery of metallurgically clean shallow gold mineralisation in a logistically simple terrain. Total Measured, Indicated and Inferred Resources are currently 31 tonnes of gold and 160 tonnes of silver. Gold occurs in an adularia-sericite epithermal system within quartz-calcite-adularia veins, breccias and stockworks. Host rocks are volcanic arc porphyritic latite-trachyte flows, their pyroclastic equivalents and volcaniclastics of upper Permian to upper Triassic age. The mineralisation was deposited in dilated zones during repeated reactivation of pre-existing structures. To-date five mineralised prospects have been defined by drilling with three reaching JORC Code Mineral Resources status. The project is in its definitive feasibility stage and is anticipated to be in construction during 2000.

Jan 1, 1999

Establishing the link between the solid, cold rock of dikes, sills, plutons, and lavas and hot, active magma chambers is the quest of igneous petrology. Differentiation of Earth, the diversity of the igneous rocks, and the spectacle of volcanism are ample evidence that magmatic processes are fundamental to our understanding of planet formation and evolution. Single gabbroic plutons, on the other hand, often show intricate and abundant evidence of the effects of crystal growth and sorting. It has not proven simple, however, to establish the basic principles of magmatic behavior leading to this crucial evidence. Because of their abundance, exposure, simple geometry, large range in size, and often straight-forward petrology, sills are excellent examples of the magma chambers. Physical and chemical processes operating in sills can be recognized that also routinely operate in many other bodies. Understanding the dynamics of sill solidification is essential to understanding the genetic links between lavas and plutons.

Jan 1, 1990

By J P. Moodie

Recent trends in flotation technology are briefly reviewed. These show that considerable development has been made as the operators, suppliers and technologists have responded to the challenges of the industry. Most of these advances have been based on empirical and phenomenological methods. There is a considerable opportunity to make further advances through a more fundamental, scientific approach. Some of this work is discussed and, although progress is being made on this front, industrial uptake has been somewhat slow. A number of specific issues facing the industry are discussed.

Jan 1, 2005

This data is intended to provide a quantative cost comparison of one 40 800 kg. pull down rotary blast hole drill versus two smalter drills in the 18 100 kg. pull down class. While this cost analysis is affected by blast design, this paper is not intended to be a treatise on blasting theory and therefore places more emphasis on costs than on blast design. All costs, prices and production rates in this paper are estimates and should be used for comparison purposes only. The drills are sized in order to maintain a production rate sufficient to stay ahead of a dragline that is excavating in an average overburden (sandstone and shale). The large drill will use 270mm bit and penetrate at a rate of 0.012 m/s (scheduled basis). The small drill will use 170mm bit and penetrate at a rate of 0.010 m/s (scheduled basis).

Jan 1, 1986

By Dunne RC

The physical properties of an orebody require determination for virtually all mining projects, new and existing. The extent and regularity of such determinations being subject to the size and homogeneity of the orebody. Such properties have an impact at the design stage of new plants, with respect to equipment specification, and thus effects capital costs; and also impacts on the operating costs of new and existing plants, with respect to power consumption, production levels and part replacements. All of these can severely alter the bottom line and can be the determining factor in the economic viability of many projects.This paper examines some of the most common properties that are measured, the procedures utilised in determining these properties, and their variability under conditions of reproducibility, and to a lesser extent repeatability.

Jan 1, 1997

By Heidecker A

Several types of drainage structure providecost-effective environmental controls for water supply to Charters Towers and its mining industry. Drainage groves maintain bank-levee, channel, pool, and spring structures. Failure of drainage structures leads to anoxic fermentation of channel fill releasing residues, such as arsenic, which would otherwise pass harmlesly by fixed on sedimentary particles.Experiments along drainage structures indicate that productive agroforestry could be integrated with expeditious development of groves to cope with environmental change.

Jan 1, 1990

By Bassett N

The Eneabba deposit, located 280 km north of Perth, Western Australia, and 30 km inland (Fig. 1) is one of the most recently developed deposits of mineral sands in the world. The area has been in production since 1974, while the Associated Minerals Consolidated Limited (AMA) operation commenced production in 1976. Total ore reserves of close to 400 million tonnes contain about 40 million tonnes of heavy minerals (proved and probable).

Jan 1, 1979

The cost of constantly extending a decline tunnel that plays a part in the actual extractive process is a revenue cost. The characteristics of such a decline tunnel are that it is dug in a series of relatively small excavations. It follows the ore body and is dug as close to the ore body as practicable. In addition, the decline allows for the extraction of ore in the immediate vicinity, with the ore being extracted in a relatively short period of time.

Jan 1, 1990

Traditionally, the term ætotal systemÆ design applied to comminution conjures images of a design that addresses the usual business and operational drivers, including health, safety and environment (HSE), capital cost, operating cost, throughput and product size. In terms of the physical process, the mine to customer type studies also exemplifies an approach that satisfies a normal ætotal systemsÆ approach. As an industry there are drivers that are forcing a re-consideration of what we regard as our total system. This modification of drivers will require changes in approach and implementation to provide the best solutions. Some of the major changes that impact the drivers are shortage of skilled personnel, changing social attitudes to remote mine site work, greenhouse gas emissions (GHGE), quality of available orebodies and geographical location of new mine sites. One approach to the challenges presented by the changing business environment is to expand the system envelope around comminution to ensure that comminution, in its widest sense, helps to meet the new realities. Background to the new drivers and constraints is provided and some of the appropriate responses are examined in relation to the impact on the total system.

Jan 1, 2007

During the last two decades, restrictions on access to land for mineral exploration and development in Australia have intensified. State and Federal legislation relating to Aboriginal land rights, national parks, marine parks, wilderness areas and other conservation areas, the surface rights of farmers in New South Wales and Western Australia, national, State and world heritage, urban developments and acquisition of land by governments for other purposes have all placed limits on mineral exploration and mine development activity. More than 20% of Australia's land area is now either unavailable for mineral exploration or available only under severe constraints. Access to this land is denied at a significant economic cost to the Australian community. There have been few attempts to quantify this cost. More importantly these restrictions have developed on an ad hoc basis promoted by single interest government departments often with little regard for rational land use planning. The mining industry has embraced the community's conservation ethic and accepted that conservation areas should be set aside and that within those areas mineral activity should be restricted. In some cases the restrictions on exploration near areas of outstanding scientific, historical, archeological or scenic importance may amount to an effective prohibition. The industry has vigorously opposed the exclusion of mineral activity in conservation areas on purely emotive grounds, unsupported by scientific evidence and in disregard of land use potential, consideration of multiple use potential or consultation with existing or potential land users likely to be effected.

Jan 1, 1987