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The weathering profile, in arid terrains, is commonly capped by different kinds of hardened crust, whose formation is related to recent or former climates. One may distinguish silcretes, calcretes and the ferruginous (or ferro-aluminous) laterites. the present keynote address mostly deals with the lateritic regolith and, moreover, the influence it has on mineral exploration. The lateritic regolith, also called "cuirasse", is a result of a massive accumulation of Fe (and/or Al) oxides on top of weathering profiles developed during former, probably seasonal humid, climatic episodes, and whose preservation depends on the characteristics of later climates. The total thickness of such weathering profiles commonly exceeds 50 m, with an almost complete substitution of the rock forming minerals by secondary minerals as kaolinite and Fe-Al oxi- hydroxides (hematite, goethite, boehmite, gibbsite). Such an alteration of the primary minerals assemblage is of course accompanied by significant changes of the chemical composition, as concerns major and trace elements. The latter are distributed amongst the main secondary mineral phases or trapped in some primary resistant minerals, but may also be leached, totally or partially. Gold is also affected by lateritic weathering, as shown for instance by morphoscopic and geochemical studies of gold grains collected in the different horizons of the profile, which indicates some dissolution followed by reprecipitation.

Jan 1, 1988

Variety among deserts is nearly as great as among other climatic environments. Common to most deserts, and to areas downwind from them, is the dominance of aeolian transport of surface material, at least during some seasons of the year. The result is dilution of local surface materials with varying proportions of chemically uniform fine sand and silt, often imported by the wind from remote areas. Fortunately, desert pavement,.even though separated from bedrock by a meter or more of nearly pure loess, is simply a diluted reflection of nearby bedrock. Infiltration of loess through the surface debris and the rudimentary soil-forming processes in the desert usually preserve the integrity of the pavement. This pavement, or its "downstream" derivatives, provides a suitable sample for exploration geochemistry if proper care is taken to circumvent the aeolian dilution. The simplest and most commonly used method of circumventing the dilution is to use a coarse fraction of soils or stream sediments, discarding or retaining the finer fraction depending upon the magnitude of the dilution. Where the coarse surface debris is composed of rock chips representative of the bedrock sources, the method is successful. Under most circumstances the coarse fraction of the surface material will give a fair representation of gross lithology and will occasionally give an indication of mineral- ization. The major drawback to this approach is that selective weathering and erosion in the vicinity of mineral deposits often lead to the loss of ore minerals into the finer fraction, leaving a coarse residue enriched in feldspar and particularly in quartz; thus, the geochemical signature from a mineral deposit is effectively reduced or completely masked. The second most commonly used method to overcome aeolian dilution, and probably the most effective at present, is to use a heavy- mineral concentrate. This approach presupposes that the chemical signature sought resides in a heavy mineral. Fortunately, the arid weathering cycle is conducive to the formation of a wide variety of secondary ore

Jan 1, 1988

By F Ouchterlony

Soviet precursors to Cunningham’s Kuz-Ram model from 1983 are described. They are rooted in the mean fragment size and Rosin-Rammler (RR) fits to sieving data and rely on approximations. Three versions of the Kuz-Ram model are presented and all three are de facto based on the median fragment size x50, even if the term mean is used in the papers. This discrepancy caused Spathis in 2004 to suggest a correction procedure for the Kuz-Ram rock factor A, which was said to explain some of the missing fines in the model. This correction, while applicable to Cunningham’s 1983 paper, does not apply to his 1987 paper, in which he presents his own A factor.Common fixes of the Kuz-Ram model’s fines issue are fragmentation models where the fines are mainly generated in a crushed zone around a blasthole. This is contradicted by careful model blasting tests. The lack of a largest block size in the RR function may lead to spurious values of the uniformity coefficient n, eg in conjunction with image-based fragmentation measurements or crusher modelling. These issues may be solved by using the transformed RR function, which has a largest block size xmax or its replacement by the Swebrec function, such as in the KCO model.The mean to median issue is investigated in some detail and it is found that using x50 instead of the mean:has a sounder theoretical backgroundis less prone to errorsis not contradicted by the original Soviet data.It is finally suggested that future work on fragmentation prediction equations focus on the use of distribution independent quantities like percentiles, eg x50, x20 and x80. Some previous work in this direction is briefly analysed and one consequence is that the n-value of the Kuz-Ram model should depend on specific charge.CITATION:Ouchterlony, F, 2015. The median versus the mean fragment size and other issues with the Kuz-Ram model, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 109–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By D Elmo, M Scoble, Y Liu, B Klein, J Scholar, S Nadolski

A cave-to-mill study being conducted at the New Afton block caving operation demonstrated the potential for sensor-based ore sorting equipment to reject waste and improve the grade of feed to the mill. The lack of selectivity and potential for dilution entry associated with the block cave mining method results in many caving operations having to mine and process material that is below cut-off grade at certain stages of production. Online monitoring and bulk sorting systems have the potential to alleviate this problem and improve the productivity of caving operations while reducing energy and water requirements for each tonne of concentrate produced.As part of the cave-to-mill study, the suitability of a range of sensors, such as X-ray fluorescence and induction-type sensors, to sort mine production at the New Afton mine was investigated. Results showed that the discrimination of ore and waste can potentially be carried out by implementing surficial sensors into the material handling system. The study also showed that a combination of sensor outputs could be used to identify a certain ore type so that pre-emptive changes can be made in the mill to improve beneficiation performance. Overall, the outcomes of the study on implementing sensor systems at block cave mines are considered to be of significant relevance to a number of existing and future caving operations.CITATION:Nadolski, S, Klein, B, Elmo, D, Scoble, M, Liu, Y and Scholar, J, 2016. Investigation into the implementation of sensor-based ore sorting systems at a block caving operation, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 393–400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Toro HCH, Von Borries GH

A brief description of the semi-autogenous grinding (SAG;) facilities of Compania Minera Disputada de Las Condes is given. A data-logging and computer system was connected to the plant inter facing the existing analog control system in a supervisory s, control philosophy. The development of a control straiov,v t,) maintain maximum power of the SAG mill atsubjected to process restrictions is shownThe present control scheme is discussed inalgorithm was designed based on correlations onLween vartaoles. Associated with this, a direct level of control was developed be, on classical control algorithms, process inter-active tuning has been included. Also, an algorithm to prevent overloading of the is discussed. Control scheme tests are presented in comparison t manual operator control under the same conditions. It is shown t the control strategy gives a more stable operation and a higher plant throughput.

Jan 1, 1985

By C Young

The identification of Critical Risks, their associated Critical Controls, and the implementation of processes to ensure their ongoing management can be difficult and resource intensive. Answering the following Critical Risk Management related questions can be challenging: • What is a Critical Risk? • What is a Bow-tie Analysis and when should it be used? • What is Critical Control? • How is the effectiveness of a Critical Control assured, and how is this measured? • Who is responsible for managing Critical Controls? • What are the implications if a Critical Control is not effective? It appears that in the mining industry’s efforts to implement the Critical Control Management Process outlined by the International Council on Mining and Metals (ICMM), instead of embedding an integrated, well understood, value adding process, we have instead created a resource hungry monster that is poorly understood by numerous layers of the organisation.

May 5, 2022

By Neill A, O&apos

The City of Kalgoorlie/Boulder is situated approximately 600 kilometres to the east of Perth (Fig. 1), and is the major regional centre of the Eastern Goldfields, supporting a population of approximately 25,000. The formation of Kalgoorlie Consolidated Gold Mines in 1989 brought the existing operat- ing entities adjacent to the city under common ownership and management. The Joint Venturers forming the management company are Homestake Gold of Australia and Gold Mines of Kalgoorlie (a Normandy/Poseidon com- pany). This traditional underground mining centre has been worked since 1893, yielding 40.8 million ounces of gold from ore with an average head grade of 10 grams per tonne. Historically the heart of the operation has been the famous Golden Mile located on the Eastern perimeter of the city, in the area known as Fimiston. The other significant operations that form KCGM are the Mt Percy Open Pit and the Mt Charlotte Underground Operation. KCGM's current production is 520,000 ounces per year, with the com- bined Fimiston operations (open cut and underground) contributing 400,000 ounces. The current expansion will increase production levels by a further 150,000 ounces. Traditionally 98 per cent of gold has been sourced from underground areas, however the recent upsurge of open cut operations is rapidly overturning this historical relationship.

Jan 1, 1991

By J Balzary, A Mohais

Dynamic market and operating conditions, coupled with an environment in which multiple objectives and trade-offs are common, pose major challenges for planners and schedulers working in any mining entity. Many mining companies recognise the need to shift from a siloed mining-focused push model to an integrated value chain, demand-driven approach, but there are still fundamental barriers in business process and the supporting technology preventing a consideration of end-to-end optimality.This paper presents some elements of experiences working with companies to adopt such advanced approaches. In addition to algorithmic elements, an approach to phased and gradual deployment of progressively more sophisticated optimisation models is described. From a practical software adoption perspective, it is believed that this last concern is also of primary importance. Next generation approaches to the optimisation of complex bulk commodity demand chains, namely iron ore and coal are presented, with case studies in the world’s largest integrated operations in Western Australia and Queensland from the raw material mined through to market. Utilising accurate simulation models supported by metaheuristic optimisation techniques, a range of ways to engineer a dynamic decision support framework that can adapt and change with the inevitable changes in commodity markets is explored. Objectives such as total revenue, margin, cost, NPV, throughput, asset utilisation, contractual penalties and bonuses, and energy consumption can be managed simultaneously across the mine, plant, logistics network, port operation, shipping and sales domains.CITATION:Balzary, J and Mohais, A, 2014. Consideration for multiobjective metaheuristic optimisation of large iron ore and coal supply chains, from resource to market, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 213–222 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

The Golden Cross is the first large precious metals mine to be both commissioned and closed in the æmodernÆ era in New Zealand. This paper discusses the life cycle of the Golden Cross mine, with emphasis on the closure process and post closure management.   The closure process has generally been very well managed, and successful, but in spite of that some on-going issues remain unresolved. Nearly nine years after the end of mining the mine owners are still actively managing the site, with no immediate end to that in sight.   The site has been described as atypical, due to the identification of a deep seated landslide below the tailings and waste rock storage facilities. However that should not be given too much emphasis when addressing the overall closure and post-closure management issues, which could well apply to other existing and future mine sites in New Zealand.   The Golden Cross can provide valuable lessons for other miners, and the issues arising at this site should be watched closely by the industry as a whole.

Jan 1, 2006

By Kurihara K, Tanimoto C

Construction and mining sites are often subject to unexpected flooding and extensive delays may occur in locating and installing emergency pumps. This particularly applies to sites located in remote areas. A simple and effective pump, called an air-lift pump, can be built from the equipment available at the working site. The basic req- uirements are a compressed air supply, air hose and conventional water pipes. The air-lift pump is comparatively in- efficient but approximately 35 per cent of the available compressed air power at the site can be applied to pumping. Suprisingly high liquid discharge rates may be obtained in suitable applications. The theoretical and practical consider- ations of the air-lift pump are evaluated and a suggested procedure for the emergency design and construction is outlined. INTRODUCTION. Sudden inundations of water into mine and development excavations require the immediate removal of the water if extensive and often irrepairable damage is to be avoided. Pumps installed in shafts or tunnels may become un- servicable due to being totally submerged during the flooding. The emphasis is on rapid

Jan 1, 1976

By A Boeing

Rock-breaker automation and remote operation improves the safety and efficiency of mining operations. This paper presents an overview of the Rocklogic rock-breaker automation system architecture that provides collision avoidance, automated parking and remote operation functionality. The system consists of a distributed computer control system that interfaces with sensors attached to the rock-breaker, the rock-breaker hydraulics and the site infrastructure. We present results of an automated Transmin rock-breaker installed in a production environment at an underground Australian mine site. The system has been in production use for over 900 days, during which there have been no reported collisions and 100 per cent adoption of the remote operation technology. As a result, Rocklogic has significantly improved the safety of rock-breaking operations and reduced the rock-breaking cycle time, thereby improving the site’s overall throughput.CITATION:Boeing, A and Douglas, E, 2014. A remotely operated robotic rock-breaker with collision avoidance for the mining industry, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 131–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By I Gray

Other than being reasonably certain of the average vertical stress being lithostatic, there can be little certainty about stress in the ground. The stresses and strains in rock are a function of gravitational effects, external load, thermal changes, diagenesis and their mechanical properties including elastic, creep and post failure behaviours. It is highly desirable to measure stress where mining is going to take place, even if the virgin stress condition has already been changed by mining. The concept of some far field stress value that is more or less constant is usually invalid and can be dangerous to use in mine design. Measuring stress is not simple. The basic processes are broken into two categories, one where the rock will not fail around the borehole in which the stress is being measured and one where the rock has failed or will fail. Because of the complexity and cost in obtaining a single, precise stress measurement it is highly desirable to have some system to be able to obtain an idea of the uniformity, or otherwise of the stress situation between precise measurements. Table 1 shows the methods for measuring stress. The first five methods work on the basis of some fairly direct measurement of mechanical rock behaviour while the last three are attempts to get some idea of stress out of core long after it is removed from the host rock. While these latter methods appear to tick all the boxes for applicability there is a great deal of uncertainty in the results that they deliver. This paper reviews the methods for measuring stress and presents two new methods. These are a three dimensional overcore system to provide precise stress measurements in rocks that will not fail around the borehole and a core ovality system. The latter can be used to provide information on the stress difference orthogonal to the core. It is particularly useful because it can be used every metre of core length.

Nov 29, 2022

By Black PM, Itaya T

Arc-type volcanic activity has been a major feature of the late Cenozoic geological evolution of the Pacific-Australian plate boundary in the northern New Zealand region. The timelspace distribution patterns of arc-type rocks reflect changes in the nature of the plate boundary as it has evolved. Inception of volcanism began in the north during earliest Miocene times (26 Ma) following ophiolite emplacement and during the next 10 Ma developed into a volcanic arc segment extending south to the present position of the central North Island. The northern part of the arc became extinct about 15 Ma ago, but activity continued in the central (Coromandel) part of the arc until about 5 Ma ago. In late Pliocene and Quaternary times volcanic activity has become concentrated in a northeast trending zone which is collinear with the Tonga-Kermadec Arc.

Jan 1, 1995

By A Stradling

For a geometallurgical program to be successful, linkage must be made between the geologists and geostaticians who understand and model the orebody, the metallurgists who determine the value that can be extracted from the different geometallurgical units, and the mine planners who develop and optimise the plan to extract maximum economic value from the resource. One of the primary purposes of geometallurgical models is in the determination of the economic cut-off between ore and waste. Recognition of the level of confidence required in the estimation of grade, throughput and recovery is critical to the planning of a successful geometallurgical program. It also helps clarify the scope of work needed to mitigate risk at each stage in the development of a new mine projectThis presentation provides some of the author’s experience with development and application of geometallurgical models for existing base metal operations. It discusses how geological units defined by lithology, structure, alteration etc, can be translated into geometallurgical ore types defined by mineralogy, ore hardness, and flotation behaviour. Examples of how these characteristics have been used to estimate key economic parameters such as mill throughput and flotation recovery at two brown-field operations are provided. The first example relates to the modelling of metallurgical performance at Teck’s Red Dog zinc-lead mine in Alaska. Prior to 2000, zinc, lead and silver recoveries from a block of ore at Red Dog were either assumed constant, or were varied according to simplistic models. Throughput was not thought to vary substantially between blocks, so an average value was used for each blended stockpile. It is quite possible that some ore-value blocks were classified as waste, and some waste-value blocks treated as ore, as a result of poor understanding of the true economic cut off across the wide range of ore types observed at Red Dog. After an extensive flotation test program, the first assay-based zinc recovery model was developed for the Main pit reserve in 2003.**This is an abstract only. No paper was prepared for this abstract**

Sep 5, 2011

Coal washery wastes comprise tailings, finer than 0.5 to 0.1 mm depending on the sophistication of the washery, and coarse reject, typically finer than 50 mm. Subaerial disposal of coal tailings slurry at about 30 per cent solids by mass results in the formation of a delta with an average slope of about 1 in 100, representing one extreme. The ravelling of coarse reject on loose-dumping, results in an angle of repose slope with an angle of about 37o (1 in 1.3), representing the other extreme. The pumped co-disposal of coal tailings and coarse reject results in the formation of an upper delta with an average slope of about to one in ten, between the two extremes. The depositional behaviour of these three waste streams is discussed and compared in this paper. The important depositional and material parameters, and a theoretical description of the processes involved, are also presented. Comparisons are made between the depositional behaviour of the various coal washery waste streams, and natural depositional systems, such as rivers, alluvial fans, and scree slopes.

Jan 1, 1998

By Faidel VV, Yushina TI, Yagodkina NG, Yatsimirsky AK, Chanturiya VA

Among the problems of the flotation of sulphides by the thiol collectors is the dependence and varieties of the flotation starting with the time and oxygen contents in the slurry. For sulphides, the flotation stage follows after the electrocatalytic oxidation of the collector with oxygen on the surface of the conductor minerals. The necessity of the oxygen for sulphide flotation (Plaksin and Bessonov, 1957) is in accordance with a corrosion model of a collector surface sorption (Salamy and Nixon, 1954). As Golikov and Nagimyak (1961) showed, the sulphides possess catalytic activity which provides the autoxidation of the xanthates in the sluny to the dixanthogen. This stage can be rather protracted, which limits the speed of the total process. Disulphides constitute important collectors for the sulphide flotation and the optimal degree of the xanthate oxidation is about 20 per cent for different ores (Abramov, 1978) or, following Chanturiya and Nazarova (1977) the surface compositions for various sulphide ores are different and an optimal oxidation degree is variable from five to 25 per cent according to the ore nature. The optimisation of the surface composition is possible by application of the dixanthogens, or by a partial chemical, electrochemical, or catalytic oxidation of xanthates (Desains, 1847; Schall, 1896; Vigdergauz, 1989). According to Rand (1977) and Vigdergauz (1991) sulphides possess different catalytic activities for oxygen electroreduction. In neutral solutions, for example, the following decrease in the order: FeS2 (Fe,Ni)9S8 CuFeS2 FeS; Cu5FeS4 Cu2S; PbS (Vigdergauz, 1991). For the cases of low catalytic activities of the sulphides, the preflotation oxidation of xanthate could be useful to optimise the process kinetics.

Jan 1, 1993

By S Pontual

The use of spectral data has traditionally been for obtaining mineral information and for mapping out alteration systems. The output from these data is typically in the form of mineral assemblages and data on relative proportions of minerals. However there is much more than just mineral information in the spectral data. Most importantly, the data allow the user to obtain vital information on mineral chemistry for some key alteration minerals. The mineral chemistry data allow the users to evaluate multiple phases of alteration of the same key mineral species, and to assess which phase is related to mineralisation. Mineral indices can be extracted from the spectral data and plotted to represent variations in the chemistry and relative proportions of key mineral phases as downhole, section and three-dimensional (3D) plots. These data can also be compared with the spatial distribution of the mineralisation by integration with geochemical and logging data. Through spatial and statistical evaluation the mineral information obtained using spectral analysis can provide vital information to assist in building alteration models and therefore improve targeting for further drilling and exploration.

Aug 22, 2011

By J Lainé, M Badawi, A C. de Araujo, Y Foucaud, C Veloso

Flotation is the one of the most used techniques for the mineral separation of non-ferrous ores worldwide. However, the increase of the complexness along with the decrease of ores liberation sizes ought to become important challenges for mineral processing, including flotation. It now appears necessary to better understand the fundamentals of the flotation process, particularly the adsorption of flotation reagents at the liquid/mineral interfaces, to propose further improvements. Flotation relies on different phenomena: surfactants adsorption, on one hand, and collision, adhesion, and transport of particles with bubbles, on the other hand. For acknowledging the reagents adsorption mechanisms, molecular modelling tools borrowed from chemical and material sciences, are increasingly used. Atomistic simulations were successfully applied to study the flotation reagents interaction with various mineral surfaces, eg of two common minerals from iron ores, kaolinite, and magnetite surfaces, or with fluorite surface, a tungsten ores common gangue mineral.

Aug 24, 2022

By D Joshi, J Rostami, M Karakus, A Eustes

The first target of mining activities on the surface of the moon is to find and extract water from the icy regolith on the moon. A test drilling unit was designed and fabricated under a NASA Early Stage Innovation (ESI) grant. A high-frequency data acquisition system was used to record drilling responses at 1000 Hz. Parameters like weight on bit (WOB), torque, rev/min, rate of penetration (ROP), mechanical specific energy (MSE), field penetration index (FPI), and the uniaxial compressive strength (UCS) were recorded for 40 boreholes in the analog samples made of regolith simulant and specialised cement. Development of the AI system and machine learning (ML) algorithms for analysis of data to evaluate strength and hence water content of icy regolith required a large data set. In this case, the data set comprising of more than one billion data points recorded while drilling into various analogue samples and cryogenic lunar formations to optimise power consumption and make bit wear adjustment during drilling operations. The tests were also repeated in the samples of icy regolith at various water content at -190C to verify the ability of the algorithms to analyse the data and to estimate the strength of the frozen formation and hence water content. The paper will discuss the objectives and methodologies used in the project and reviews the testing program and the machine learning (ML) algorithms ability to identify various formations along the exploration boreholes.

Sep 1, 2024

By Weatherstone N

Ironstone outcrops on the Savage River were discovered by State Government Surveyor C. P. Sprent in 1877. The limonitic outcrops were initially regarded as the surface expressions of pos- sible tin-bearing lodes, the tin deposits at Mt. Bischoff to the east having been found in 1871. By the turn of the century, shafts, adits and trenches had been developed on the deposits in the unsuccessful quest for gold, silver and base metals. The deposits were first reported as a possible source of iron ore by Tasmania Department of Mines (TDM) geologists in 1919. Modern exploration began in 1956 with the area registering the best magnetic response during an aeromagnetic survey of North- western Tasmania by the Bureau of Mineral Resources (BMR). The area had previously been reserved by TDM in anticipation of the lifting of the iron ore embargo. Reconnaissance Geologi- cal mapping (TDM) and grid-based magnetometer surveys (BMR) indicated that resources of iron-bearing material could approach hundreds of millions of tons. This provided the incentive for two diamond drill holes funded by TDM which demonstrated iron mineralisation in substantial tonnages, suitable grades and, fol

Jan 1, 1988