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By Hoskings AD

Bolting forms a prestressed elastic layer of rock which is capable of supporting loads at right angles to the bolted surface. Investigations on rock bolting made with a number of different models give rise to empirical and theoretical prin- ciples for the formation and action of the layer. In the models, flat and arched layers of many materials were used simulating rock conditions ranging from closely interlocked blocks to fragments of various shapes. Results of observations made in the underground works of the Snowy Mountains Scheme are related to the mode of action of bolted surface layers of rock. There is abundant experimental, theoretical and practical explanation for the well-demonstrated capability of bolting as a means of rock support.

Jan 1, 1971

The Golden Valley Volcanic Centre has been recently interpreted as being a combination diatreme breccia pipe and rhyo-dacite flow dome complex of Permo-Carboniferous age that intrudes basement granitoids and sediments of Ordovician-Devonian age. Exceptionally good exposure at the Centre has enabled the relationships between different lithologies to be determined. This, along with petrological studies, has led to a detailed understanding of the geological environment in which the complex formed. Gold, silver and base metal mineralisation have been recently shown to be associated with the Marginal Breccia at the perimeter of the diatreme. Comparisons have been made between the geology and mineralisation in this system and several similar diatremes which also contain gold-base metal sulphide mineralisation.

Jan 1, 1990

The ore mined from the Lead Lode of The Zinc Corporation leases consists of a fairly granular mixture of galena, marmatite, chalcopyrite, tetrahedrite, pyrrhotite, pyrite, and lollingite with a gangue association of calcite, quartz, bustamite, rhodonite, mangan-hedenbergite, garnet, fluorite, mangano-calcite and apatite. The silver content of the ore occurs in three minerals tetrahedrite, dyscrasite, and pyrargyrite, the last two mentioned occurring in microscopic association only. Other metallic and gangue minerals are also present in this complex mineralogical association, but do not influence the milling operations.Fortunately, the silver minerals favour the galena and chalcopyrite as their host minerals, thus facilitating the recovery of both copper and silver in the lead concentrate. The ore from the Lead Lode assays from 14 - 18 per cent lead; 3.0 - 4.5 oz silver per tonne, and 9.5 - 12.0 per cent zinc.A parallel lode, known as the Zinc Lode, is well developed in The Zinc Corporation leases. This lode assays from six to eight per cent lead, 1.5 oz silver per ton, 18 - 25 per cent zinc with a siliceous gangue. The common Lead Lode gangue minerals, calcite, rhodonite, bustamite - are very rare in present underground exposures. No metallurgical work was done on this ore during the pilot plant operations.The aim in the milling process is to produce:1. A lead concentrate with the maximum economic recovery of lead, silver, gold, copper and antimony, and minimum zinc content.2. A zinc concentrate with the maximum economic recovery of zinc, cadmium, and cobalt, and minimum iron, arsenic and fluorine content.3. A waste residue containing sufftcient granular material to be utilised as underground fill.In considering the economics of the milling practice the above three requirements plus consideration of the tariffs submitted by the purchasers of concentrates were the deciding factors in the evolution of the present milling practice.Towards the end of 1924 The Zinc Corporation Limited added to and adapted the old zinc tailings plant for the treatment of 5000 tons of crude ore per week. This plant, which operated until January 1936, was in general principles similar to the standard Broken Hill methods of ore concentration, whereby the galena was recovered by the gravity concentration methods of jigging and tabling with selective flotation concentration of the residual galena and marmatite. One important difference from other Broken Hill plants was that the primary grinding of the jig tailing was performed with flint-loaded mills operating in closed circuit with revolving screens. Two primary grinding sections were installed, each consisting of two 5 ft diameter by 10ft long tube mills loaded with flint pebbles working in closed circuit with four 3 ft diameter by 3 ft wide revolving screens covered with 22mesh Toncap woven wire screen with 0.57 mm opening. Each section carried a circulating load of 28.3 tons per hour for a jig.

Jan 1, 1994

Pisolitic iron ores (also known as channel iron deposits) are an important resource of medium-grade iron ore in the Hamersley Province of Western Australia. They are a special case of transported pisolitic ferricrust, differing from normal transported ferricrust only in the exceptionally high iron and low alumina content. The pisoids typically range up to 5 mm in diameter with abundant particles of ferruginised fossil wood up to 15 mm in maximum diameter preserved in the sediment. Field observations indicate that pisoliths are commonly initiated by the action of raindrops on iron-rich soil. Pisolites form by the impact of raindrops forming coated beads of ferruginous soil, which after dehydration obtain additional coatings during successive showers. Thick deposits of pisolite that are transported and deposited primarily by sheetwash form in the distal regions of the pediment. A size range limited to particles that may be transported by extremely shallow water characterises the abundant fossil wood fragments. The absence of fine sedimentary layering in pisolitic iron ores is explained by the action of soil-forming processes after deposition, while the major coarse bedding features derive from successive erosional and depositional events in the evolution of the pediment. They are not deposited in channels by rivers which, in arid to semi-arid conditions, typically deposit quartz sands and gravels with characteristic point bars and current bedding, abundant ferruginous granules, but rarely pisoids. However, they may fill abandoned river channels.

Jan 1, 2007

Batterham and Algie began their paper on: `The role of technology in the minerals industry' (1995) by noting that while: it is often stated that innovation is central to the economic survival of mining and minerals processing in the face of global competition, .. . technology is often far from a core strategy in our industry. This point is correct. Throughout the world, as a broad generalisation, mining companies do not value technology development as a principal means of gaining competitive advantage. It is important to understand why this is the case. Batterham and Algie address this question by making distinctions between innovation, technology and research. They note that while: all successful (mining) companies are good at innovation . . . that innovation can proceed without any research and development and that it is innovation that generates the competitive advantage, not research and development per se. In this paper we accept these arguments. However, our focus is somewhat different. Whereas Batterham and Algie took a mining company's perspective on the technologies of mining and processing, we take a broader view of the opportunities for technology development for company Australia but, in order to focus the argument, we restrict our discussion to the area of mining (rather than processing); we focus particularly on mining systems and mining equipment. We begin by looking at the motivation of companies operating in any industrial sector to invest in research and development. Figure 1 recognises four levels of industrial maturity. For companies in the embryonic and growth stages R&D often is essential to initiating and developing the business. Mining, on the other hand, is a mature industry. In mature industries the conventional roles for R&D are to reduce costs, to extend product differentiation, or to develop new technology with the aim of rejuvenating the business. Next we ask whether these general-industry arguments apply to the mining industry. If they do then the mining industry should value R&D more highly; after all cost reductions and business rejuvenation are goals that are worth achieving. On the other hand if, for whatever reason, these general arguments do not apply to mining then this may lead the mining industry to invest only modestly, or not at all, in R&D. In this event, while this may be a rational decision for the mining industry, it may not be in the best interest of a nation like Australia where revenues from the sale of mineral products represent an important part of the country's economy.

Jan 1, 1997

By Moore J

Gunpowder Copper Ltd is using in-situ leaching to extract copper from the Mammoth sulphide ore deposit in north-west Queensland. To increase metal recovery, ore is fragmented using conventional underground longhole drilling and blasting techniques. Although the upper levels of the orebody had previously been mined by open cut and underground methods, significant reserves of copper existed around old workings. To safely and economically recover this resource, a decision was made to fire the remaining pillars in the upper part of the mine by a single 1.37 million tonne mass blast in February 1992.This paper records the planning, design, and implementation of the Mammoth mass blast. Geological and geotechnical aspects are summarised, to explain the reasons for such a large blast. Drilling, charging and blast initiation are discussed in detail, to show how standard equipment and products were applied to a unique task.

Jan 1, 1992

This paper is based on studies made intermittently from 1937 to 1950. Its object is to describe the surface geology and the tin lodes, and to relate the lodes to the structure of the field.PREVIOUS REFERENCESR L. Jack made his first report on the field in 1880, but his principal report was made in 1883. W. E. Cameron described the Great Northern lodes in 1904. Numerous later reports on various mines were made by L. C. Ball, J. H. Reid and C. C. Morton, the most important of which were on the Black King, Good Friday, St. Patrick and the Great Northern Gully Shaft.GENERAL GEOLOGYJensen maps the Herberton area as part of a granite massif intruding rocks of two ages, the Younger Metamorphics of Silurian-Devonian age, and the Older Metamorphics of Older Palaeozoic age. The distinction is apparently based on lithological data. The Older Metamorphic rocks occur as inliers in the granite massif to the west and east of Herberton (Fig. 1).The area described consists of granite traversed by numerous dykes. West of the area, approaching the Older Metamorphic rocks, the granite becomes finer grained as if chilled towards its contact, and the dykes more numerous. To the east, passing from the Nova Scotia mine to Mount Lavery there are numerous dyke rocks, but the outcrops are poor and knowledge of the geology indefinite. The area is the main tin-producing area. To the west there are comparatively small tin lodes in the granite, and the "Copper Firing Line" occurs in the Older Metamorphic...

Jan 1, 1951

At 11 p.m. on Tuesday, 24th July 1979, an explosion of methane gas in a three heading development panel at Appin Colliery resulted in the deaths of fourteen men. The explosion followed after or was asso- ciated with a changeover of the ventilation to achieve a central intake between two returns. Investigation by Inspectors was followed by separate Judicial and Coronial Inquiries. Investigational information aimed at understanding the circumstances of the ex- plosion was prepared for the Inquiries. Recommendations following the Judicial Inquiry have been adopted by the Department of Mineral Resources.

Jan 1, 1981

The difficulty in screening of ores when the moisture contents reach certain critical levels has resulted in mining circuits using wet processes for screening. While this has been acceptable in past years it is no longer acceptable in certain countries and where the mining company is looking to reduce its impact on the surrounding environment.   Various mining companies have been looking at ways to remove the need of using water, with all its inherent drawbacks and to be able to produce its desired products in a dry process.   This would have the benefits of less environmental impact and cost, (due to not requiring wet processing equipment), less power consumption (reduced equipment needed), no corrosion issues, no contaminated waste waters and reduced maintenance activities.   Until recently this has proven elusive or with technical restrictions with current available acceptable technologies for high capacity plants.   One major mining company began seriously exploring ways to overcome this dilemma so that they did not replicate their current ways of operating for their new expansion plans.   They partnered with Metso Minerals to undertake extensive groundbreaking laboratory test work and provide potential solutions as to how to solve this. The laboratory test work proved interesting enough to design, manufacture and test on the actual mining site a prototype screening machine in the circuit.   This break through in screening technology reduces the environmental impact on the area in which the mine is located by: eliminating the storage and use of water, reduction in energy consumption due to having no pumps in the plant, reduction in plant costs and the upstream affects on the environment process used to manufacture and ship the materials the plant structure is built from, and no large tailings dams to take up land space and affect the environment through groundwater/ water table contamination and the negative effects on animals and ecosystems Laboratory test were conducted and a full size machine was installed at the plant site along side conventional machines. The screen size (2.4 m wide x 6.1 long double deck) was determined by the size of screens currently in operation at the mine. The parameters that were explored were: types of screen surface (polyurethane, woven wire etc), types of screen motion (linear, circular or elliptical), angle of motion ( 40,45,55,60 degrees etc), and throw (amplitude), speed and 'g' force.

Jun 1, 2010

By P J. Harris, D J. Bradshaw

Surface oxidation of sulfide minerals, such as that found in the regions of a sulfide ore body near the water table, can have a significant impact upon flotation. This theme has been explored for Merensky ore type sulfides where an ore containing pyrrhotite, pentlandite and chalcopyrite was thermally oxidised and the role of potential remedies investigated. Back-scattered scanning electron microscope images are presented showing the oxidation layer which formed in the mineral surfaces. These oxidation layers were depleted in both sulfur and iron with incorporated oxygen. Flotation recovery rapidly decreased with increasing oxidation, particularly after 27 days and reached a plateau after 50 days. Up to 27 days, this effect could be partially overcome with higher collector additions. Oxidation had more impact upon the finer size fractions, particularly for pyrrhotite. For more heavily surface oxidised samples, ultrasonic treatment prior to collector conditioning was found to improve flotation recoveries. This treatment had the greatest effect upon chalcopyrite particles. Sulfidisation was successful in restoring the flotation recovery of the heavily oxidised sulfide minerals. Longer sulfidisation conditioning times were not conducive to good flotation recoveries of both oxidised pyrrhotite and pentlandite due to oxidation of the freshly formed sulfide surfaces. For maximum flotation recoveries of oxidised pyrrhotite, pentlandite and chalcopyrite, different sulfidisation conditions are indicated. It appears likely that in a mineral processing operation treating oxidised Merensky type ores, two stages of sulfidisation employing different conditions would be required.

Jan 1, 2005

BHP is the world's largest copper concentrate producer with production from mines at Escondida (Chile), Ok Tedi (Papua New Guinea), and Island Copper (Canada). The entire concentrate production is further processed into refined copper by third-party smelters around the world. In anticipation of an expansion in the global copper concentrate production capacity and a corresponding increase in treatment and refining charges by copper smelters, BHP has continuously evaluated various opportunities for downstream copper processing. An expansion in the Escondida mine production, combined with BHP's interest in processing some of its concentrate production on-shore in Chile, ultimately resulted in the development of the Escondida Leach Process. This process was specifically developed for higher grade concentrates, such as from Escondida. An ammoniacal lixiviant and air are used under ambient conditions to leach less than one-half of the contained copper values. After solid-liquid separation, the solution is subjected to solvent extraction regenerating the ammoniacal lixiviant and the copper loaded organic phase is stripped in spent electrolyte returned from the electrowinning plant where ultra-high quality SX-EW copper is produced. The solid leach residue can, if required, be upgraded by flotation to produce a high-grade copper concentrate with improved fuel values and a pyrite tail for disposal. After an 18-month bench and pilot plant scale program and an engineering feasibility study, Minera Escondida Limitada decided to build an 80 000 tonnes of copper per year facility near Antofagasta, Chile. The installed investment cost amounted to around $160 million. The plant went into commercial production in November 1994 and better than 99.9995 per cent Cu cathodes were produced right from the start. BHP believes that the process and the commercial plant are an excellent example of a novel approach advancing the science of copper metallurgy in harmony with present demands for environmentally sound processes and high quality products.

Jan 1, 1995

By L D. Redden, M G. Nelson

Mechanical flotation machine design is typically based on hydrodynamic analysis, with scale-up calculated by geometric proportionality. End users often specify and purchase machines on the basis of retention time, characterised by the æ$/m3Æ approach; they may also consider the manufacturerÆs installed base. In some applications, end users also consider specific energy and the impact of energy consumption on operational costs. In other cases, a decision may be based on machine type (forced-air versus self-aspirating) and perceived metallurgical or operational advantages of one machine type over the other. With regard to metallurgical performance efficient bubble-particle contact is very important and is primarily influenced by two factors:the concentration and size distribution of bubbles in the machineÆs contact zone (the volume enclosed by the disperser); and the number of times that slurry is pumped through the contact zone. The second factor is a function of the machineÆs pumping rate and its retention time. Field data show that pumping efficiency is independent of aeration rate. In this paper, a new dimensionless number for the characterisation of flotation efficiency is presented. The contact frequency number (CFN) is defined as the number of times a given volume of slurry passes through a machineÆs active contact region, and is given by: CFN Qp/Qf, where:Qpis the pumping rate through the contact regionQfis the volumetric feed rate to the machine

Jan 1, 2005

By D A. Deglon

Solids suspension is important in the design and operation of mechanical flotation cells, and is a necessary precondition to particle collection. Most of the fundamental hydrodynamic research that incorporates some aspect of solids suspension was done by Arbiter, Harris, and co-workers, or Schubert and co-workers. However, a need for research into solids suspension in mechanical flotation cells exists, since very little has been done since the late 1980s; a time that also coincides with the advent of round mechanical flotation cells and the subsequent dramatic increases in maximum flotation cell sizes. In this work, concentration profiles and critical impeller speeds, Njs, were measured in a 0.124 m3, round cell fitted with a 0.150 m, Bateman impeller mechanism. Two solids size fractions (75 - 106 and 150 - 250 ¦m) were tested, in ungassed and gassed conditions (JG = 0, 1 cm/s) and at various impeller speeds (300 - 900 rpm). The effectiveness of solids suspension was quantified in three ways in terms of extent of off-bottom solids suspension, suspension height (extent of solids distribution), and variation within the solids distribution, which together present a complete quantitative picture of solids suspension and distribution within the cell. Consistent trends were found when these effectiveness criteria were considered against relative impeller speed, in terms of percentage of critical impeller speed, N/Njs. Off-bottom solids suspension is complete at or above 100 per cent of Njs, with significant sedimentation occurring as the impeller speed drops below 60 per cent of Njs. Suspension heights consistently reached a level equivalent to 90 per cent of the tank diameter at the critical impeller speed, and dropped off significantly as N/Njs dropped below 60 per cent. The variation in the solids concentrations within the sampled profiles showed consistent trends in two-phase but not under three-phase conditions. The paper concludes that the critical impeller speed, Njs, commonly used in the design and operation of standard stirred tanks, is a very useful solids suspension benchmark for describing all aspects of solids suspension in mechanical flotation cells and should be correlated to system conditions.

Jan 1, 2005

By L Smith, R Beckie

An intermediate scale (8 m + 8 m + 5 m high) constructed waste rock pile experiment was built upon a contiguous grid of 16 gravity drainage lysimeters to investigate the flow of water in unsaturated waste rock. Average net infiltration to the uncovered waste rock pile is 55 per cent of precipitation. Large rainfall events have net infiltration of 55 per cent to 85 per cent. Net infiltration estimates range from 23 to 120 per cent of precipitation between lysimeters. Small-scale lysimeters of less than 4 m2 area are shown to be poor predictors of net infiltration for uncovered waste rock. The appropriate size for lysimeters increases with increasing flow rate. The residence time distribution has an estimated median value of 3.0 to 3.9 years under average infiltration conditions. Water flows within the fine grained matrix, within larger pores (macropores), and in matrix free areas of the pile. In situ tracer concentrations vary between pore sizes, and between spatially distinct areas of the pile, indicating water geochemistry may also be variable. Water samples collected from in situ soil water samplers are dominated by the most mobile water fractions. In situ measurements of water content and matric suction are compared to the measured outflow. The data indicate the focusing of flow in spatially distinct areas can make in situ instrumentation a poor (non-conservative) predictor of volumetric water flow.

Jan 1, 2003

By G Ryan, Yu Nazimova

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. This paper aims to highlight the global exploration opportunities that exist in connection with Ural-Alaskan (UA)-type intrusions. The key economic importance of UA intrusions is the existence of metallic platinum (mainly iron-platinum alloys) associated generally with chromite mineralisation and located within a dunite core, especially its coarse-grained part. Being very dense and resistant to erosion, platinum can form rich placers as the intrusion erodes. Big multimillion ounce placer platinum deposits of this type have historically been successfully mined for many years (eg Russia, Colombia and Alaska).However, large-scale exploration and mining of platinum placers currently occurs only in the Russian Far East. Outside of Russia, there is now little or no understanding of this type of deposit and its economic importance. Using successful operations in Russia as examples, it is demonstrated that there are many opportunities for similar discoveries all around the world, especially around the Pacific Rim, where such intrusions tend to be concentrated. Examples of highly prospective areas in eastern Australia and New Zealand are given. There is also excellent potential in British Columbia (BC) Canada, South-East Asia (Philippines, Indonesia, Papua New Guinea and New Caledonia) and South America (Colombia and Ecuador).CITATION:Nazimova, Y and Ryan, G, 2015. Platinum potential of the pacific rim of Ural-Alaskan-type intrusions, in Proceedings PACRIM 2015 Congress, pp 665–670 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By S Kodate, Ö Aydan, Y Suda, J Tomiyama

Fracture zones are commonly found in the Earth’s crust. These zones may cause very severe engineering problems. Therefore, the formation and the assessment of the mechanical characteristics of these zones is of great concern for rock engineers. A new double shearing jig was used to study the formation of shear zones in rock under static and impact loading conditions using the device developed by the authors. A series of experiments were undertaken to investigate formation on the formation and characteristics of fracture zones in laboratory. Although actual fracture zones are more complicated, various tests give some insight view of the formation of fracture zones as well as some information on their mechanical behaviour under both dynamic conditions and static conditions. The authors report the outcomes of these experiments and discuss their implications in practice.

Nov 29, 2022

By M Rankin, F Medina, R Verburg

We conducted a preliminary assessment of an extensive deposit of historic tailings discharged over a period of 40 years to the shoreline along a Southern Peruvian coastline. The tailings formed an extensive beach approximately 2.4 km long and 300 m wide. The tailings consist principally of pyrite (37 to 59 per cent), hematite (nine to 20 per cent), magnetite (three to 13 per cent) and quartz (11 to 36 per cent). The present operating company was required to evaluate the feasibility of capping the ocean side tailings deposit, however, given the size of the undertaking and the potential to reclaim residual minerals from the tailings, it was prudent to first evaluate whether capping would in fact reduce the impacts to the marine environment. Therefore this preliminary assessment examined: 1. metals contamination in tailings, shoreline porewater and marine sediments; 2. reactivity of tailings and acid generation potential; and 3. the potential for biological effects from metal contamination in the uplands tailings (solid phase) and beach porewater. Based on mineralogy, column leach studies and chemical results, the upland tailings have a high geochemical potential to acidify and release metals, especially copper, nickel and zinc, should they be subject to oxygenated and aqueous conditions. But, the extreme arid climate results in very low potential for precipitation and virtually precludes the transport of acid drainage reaction products from the upland tailings towards ocean. Wind erosion caused by offshore winds is likely a small source of tailing transport to the ocean. Since some potential exists to reprocess the tailings in the future, capping does not seem justified at present.

Jan 1, 2003

Low-grade, porphyry copper type mineralization at the Moonmera prospect is related to the intrusion of a granodiorite porphyry mass into the Upper Permian "Gracemere granodiorite". Significant copper mineraliza- tion appears to be associated with the alteration assemblage quartz-sericite- kaolinite. The ore shell is surrounded by a zone where montmorillonite and kaolinite are in greater abundance and this assemblage is over- lapped, mainly at depth, by potassium feldspar alteration. Secondary biotite is abundant throughout the mineralized zone. Preliminary sulphur isotope results on the sulphide mineralization are compatible with a magmatic origin for the sulphur.

Jan 1, 1974

By O Aydan, R Ulusay

Blasting is the most commonly used excavation technique in mining and civil engineering applications. Blasting induces strong ground motions and fracturing of rock mass in rock excavations. Particularly, high ground motions may also induce some instability problems of rock mass and structures nearby. Furthermore, it may cause some environmental problems due to noise as well as vibrations of structures near the populated areas. Furthermore, flyrocks is another major issue for the safety of people and damage to machinery and equipments when blasting is employed. In this study, the authors explore the ways how to estimate the ground motions as a function of distance, amount of explosive, number of holes. The ground motions were measured by stand-alone accelerometers developed by the first author and some empirical relations are developed. The effect of ground motions on the instability issues of benches such as sliding, toppling and rockfalls were investigated. Furthermore, the flyrock issue is investigated and some empirical relations to estimate the maximum distance of flyrocks from the blasting relations are compared and discussed. CITATION:Aydan, O and Ulusay, R, 2018. The ground motions induced by blasting in open pit lignite mines and its environmental effects, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 142–151 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By C Robertson, J Campos

The South African mining industry first experienced en-masse use of electronic detonators in the Narrow Reef environment using AELÆs ElectrodetÖ pre-set delay system. In recent years, programmable systems such as AELÆs SmartdetÖ have also established their position, and within both AEL and the mines there has been important learning around the strengths and weaknesses of these systems. In general, the fixed delay systems tend to be more easily appreciated by less-skilled work teams, and are very well suited to simple layouts, especially long, narrow blasts. However, development of programmable row controllers and series delay inserts has greatly expanded the field of usefulness of these systems while retaining most of the simplicity of use. The programmable systems are immensely flexible and therefore able to function under any condition, but require a higher level of discipline and knowledge. Much has been done to address this issue and make the systems user friendly, so the systems have converged to some extent. These systems are both valuable tools for achieving control over blasting in underground and surface applications. The choice of system is very dependent on the prevailing conditions. Accurate timing with electronic enhancements continues to show an increasing range of benefits to mining operations. There is a strong parallel with non electronic initiation systems which helps to understand the appropriate use of the systems.

Jan 1, 2001