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By Sijing Cai, Chengpu Zhou

The requirement of mineral resources is increasing as the economy is continually increasing in China. The mining practices of various complex sulphide deposits and precious metal deposits, and the treatment of mine tailings and other industrial solid wastes, have greatly improved fill quality in the metal mines. From early-1980s, high density slurry fill, paste fill of total tailings, low density slurry fill with addition of silicate gelling agent, etc has been studied and applied, and some progress has been achieved. Today, mine tailings, slag and power plant ash are widely used as fill materials in mining. A number of cemented fill mines equipped with large capacity trackless mining machines are in production. Recently, The 3rd Chinese National Symposium on Mining with Backfill, 1995 has been held, the progress of fill technology in mines has been exchanged and summarised. In the paper, some aspects of fill technology used in the metal mines of China are briefly introduced and some applications of fill research work are presented.

Jan 1, 1998

By T Smith

The evaluation of a new mineral resource and its economic viability is critically dependant on the quality of the assay data as it is this data that defines the grade of the resource. However, all too often the procedures of sampling and chemical analyses used to generate such data are neglected or given little consideration until final modelling and evaluation are under way. This approach frequently requires large reassay and/or re-sampling programs to be undertaken to validate or to improve the integrity of the data base. This paper outlines a step by step approach to ensure quality data is achieved and then maintained throughout the entire exploration and resource development program. This involves the use of correct field sampling methods, assay methods designed to give the required levels of accuracy and precision and quality procedures in place to monitor the effectiveness of the overall process. Thorough documentation is an overriding and necessary part of the entire process. Practical examples are given to demonstrate the use and value of these methods.

Jan 1, 1998

By Sterns UJ, Weller KR

Grinding to sizes less than 80 per cent passing 20 ¦m in both primary and regrind circuits is becoming increasingly important in processing metalliferous ores, as many of the remaining orebodies are very fine-grained and refractory. The process of very fine grinding, however, is expensive, and neither the performance nor the design criteria are well understood. This paper presents some findings from a collaborative research program, one of the objectives of which has been to better understand and improve the performance of very fine grinding circuits. Data from surveys of an industrial tower mill grinding circuit are reviewed and analysed using the population balance models of the CS]RO and 7KMRC. The performance of both models with regard to changes in feed size distribution, ball load and feedrate is assessed using these data. From comparisons between pilot and full scale tower mill operation a prototype scaling methodology is also presented which shows promise in allowing the models to be used to predict the effect of changes in mill Design.

Jan 1, 1993

The operation of cyclones and cylinders is briefly described and com- pared, and a number of recent applications in mineral, gold and coal plants discussed. The capacity of an existing pump and cyclone in a circuit can be sig- nificantly increased by retrofitting a cylinder in series to predensify the cyclone feed. The cyclone overflow product size can also be adjusted and controlled using a variable aperture valve between the cylinder and the cyclone. This predensifier-cyclone system has been used at plant scale to con- trol the pulp density of the feed to cyanidation in gold plants, to size flotation feeds before split conditioning and to deslime and classify in gravity plants. Application in a typical regrind circuit is considered. Cylinders and cyclones also have numerous applications in water management systems, e.g., degritting mine and plant waters to protect pumps, sprays and other equipment. Screen undersize and flotation con- centrate dewatering circuits are described to illustrate how suitable stream recycles can reduce water consumption, optimize fresh water use and improve efficiency.

Jan 1, 1988

The cost-effectiveness of blasts involving radiating blastholes is cur- rently restricted in the following ways. (a) Significant percentages of potential explosion energy are not being liberated; the collar sections of some charges are being dislocated and/or desensitised by the detonations of adjacent earlier-firing charges. (b) If the minimum charge spacing is too small, detonation of an early- firing charge can initiate an adjacent charge sympathetically, thereby eliminating the benefit of any intended inter-charge delay. (c) The overall distribution of energy is poor. Appreciably better fragmentation would be achieved if current drill- ing patterns were to be replaced by staggered fans/rings having a toe spac- ing : burden ratio of about 4 : 1. This wide-spaced pattern would enable a higher percentage of the potential energy to be released, would reduce the incidence of sympathetic detonation and would provide a superior overall distribution of this liberated energy. If improved fragmentation is not required, the proposed fan/ring design should allow a significant expansion of the blasthole pattern with consequential cost savings in drill- ing, explosives and initiation.

Jan 1, 1988

By Mckenzie CK

Delay scatter, although widely recognised, has rarely been studied with the aim of critically reviewing blast designs. With current trends towards increased deck charging, and the effect on the number of separate delays in blast designs, delay scatter is shown to have a rather profound influence on the control of initiation sequence and the ability to successfully con- duct pre-splitting and smooth blasting. Determination of realistic delay scatter distributions is the first step towards application to blast design. Delay scatter must be evaluated in terms of deviation from the nominal time, not in terms of deviation from the batch mean, since the latter is not usually known without specific testing, requiring accurate timing instrumentation. Computer programs using Monte Carlo simulation can then be developed to investigate the probabilities of out-of-sequence initi- ation or near-simultaneous initiation within any specified interval. The procedures have been applied to both production and development blast designs in Australia and Chile to improve initiation sequence control and to rationalise and simplify blast designs.

Jan 1, 1988

On-line radioisotope gauges determine information on the characteristics of ore to enable improved control of processing operations. In the metalliferous mineral industry, in-stream analysis systems based on radioisotope X-ray techniques determine concentrations of valuable minerals at various stages of the concentration process. In the coal industry, on-line gauges determine ash and moisture contents, and the specific energy of coal.In-stream analysis systems developed in Australia are installed in about 30 mineral concentrators. Their use has led to the increased recovery of valuable minerals, and the time taken to recover the cost of installation is usually several months. The savings to Australia resulting from use of these analysis systems is estimated to be more than $A 15 million per year.Australian experience in the training of mineral industry personnel shows that the most effective approach is to combine courses on nuclear techniques and control of processing operations. This is the basis of Australia's contribution to the minerals sub-project of the United Nations Development Program (UNDP) Industrial Project.

Jan 1, 1985

By W R. Hancock

Control of complex machinery through the internet is investigated through the construction of a vehicle prototype developed using off-the- shelf hardware. The vehicle was able to be controlled remotely through the use of a client side interface connected to a steering wheel and foot pedals. By attaching sensors to the vehicle, data could be collected from which one could infer the effectiveness of such a control system. The effect of latency on control was monitored by the introduction of an artificial latency, simulating a wide variety of internet-related issues, such as unstable connections and dropouts. Sensor data could then be used to gain an understanding of how the system could be improved though either control or interface design. A path tracking experiment was conducted to gather controllability data and it was found that such a system is plausible within a reasonable range of latencies. It is expected an area of future research would be an extension of this current project, applying the information gained to real world control systems.

Jan 1, 2008

By T Kitajima, T Kawaguchi, T Nakamura

Carbothermic reduction of iron oxide is an attractive mechanism to produce metallic iron, since it can directly utilise coal as both reductant and fuel. To improve energy efficiency and productivity of the metallic iron production based on this mechanism, the combustion bed process packed with the composites of iron oxide and coal powder was experimentally evaluated. The process has a potential of high heat efficiency since it can automatically utilise the heat of reduced materials as that necessary to the subsequent reduction of the composite by a large heat exchange rate between the packed particles and gas flowed across the bed. However, it is hard to perfectly prevent the reoxidation of formed metallic iron in the bed. The present paper reports the effect of coal content, pellet size and so forth on the reduction/metallisation degrees of the samples after the reduction experiment. It also discusses the effect of pretreatment of the composite pellets using CaO bearing materials to suppress the reoxidation of formed metallic iron in the bed.

Jan 1, 2000

By Takasaki Y, Ohzeki S, Hotta H

TO measure high temperature properties of blast furnace burdens ( the change of gas permeability accompanied by contraction, soft- ening and melting ) which govern the gas flow and its distribution, a series of experiments were carried out under simulated blast furnace conditions, using sinter, acid pellets and self -fluxing pellets. 1) The high temperature properties are affected by the ore's reducibility ( up to 1000 -1200¦C ), and the composition, and volume of gangue before reduction. Generally, the burde- ns with high basicity ( Ca0/Si02 ), high reduc- ibility and low volume of gangue have good high temperature properties. Good high temperature properties are : a high temperature at which the gas permeability rapidly decreases, a high melting point and a low maximum pressure drop. 2) Using acid pellets, slow-down of red- uction rate occurs around 1000¦C because the pellet forms a dense metallic shell, while its slag core, resulting from a FeO, Si02 and A1203 reaction, has a lower melting point. 3) The addition of MgO sources improves high temperature properties both of sinter and Pellets.

Jan 1, 1980

By S D. Golding, K Baublys, V Nanjappa, C J. Moran

Water reuse is becoming an integral component of the water management strategy on mine sites. This practise is being driven by corporate sustainability goals, community and societal pressures to demonstrate improved water stewardship, as well as climate and regulatory pressures. However, water reuse often results in water quality compromise which can then result in decreased recovery through problems in processing circuits, product quality, and an increased likelihood of discharge of water that cannot meet environmental regulatory requirements. On most mine sites, there is usually a disjuncture between water quantity management and water quality management with the latter being managed solely as an environmental problem. It is becoming increasingly clear that water quality and quantity must be managed as an integrated system. In order to integrate water quality and quantity management to achieve multiple objectives the dynamics of water and constituents must be understood. Using examples from a study being conducted at a coal mine in the Bowen Basin, this paper will outline the dynamics of water and salts on the site.

Jan 1, 2009

By Marshall B, Gee R. D

Geological data processing by machine enables'an increased rate of coverage, better supervision and control of field programmes, increased effectiveness of field operators, and vastly improved access to old and new field data. Even a system of restricted felxibility enables a mapping programme to be organ- ized and conducted independent of personnel changes, whilst elimination of much compilation time increases the rate of cover- age such that it relates to mode of transport and geological complexity rather than to personality factors. A machine is useful only if applied to tasks suited to its capabilities, and must be aimed at those types of mapping in which a limited number of attributes adequately define the problem, and the data is of a form suited to coding and is normally collected in sufficient abundance to make compilation wearisome. Machine systems are therefore unsuited to most types of lithological mapping and to most types of exploration in new areas, but have proved useful in many branched of cartographic geophysics (e.g. gravity and magnetics), and in cartographic Geochemistry.

Jan 1, 1969

Geostatistical analysis, resource estimation and three-dimensional modelling of the gold grade distribution was undertaken using exploration drillhole data taken from the Mt Leyshon gold mine. The main aims of the project were to provide an independent estimate of the primary gold resource and to improve the estimate by better understanding the statistical distribution of gold and the establishment of more robust variograms. These criteria have been achieved by the removal of low grade sub-populations, increased sample size and access to data from the most recent drilling program. The outcome of this statistical study has led to a lowering of the sill and nugget variance of the variograms used. Distinct geometric anisotropy was identified in all the resource estimation zones and was used to model gold grade distribution.Two independent resource estimates were established from the primary gold resource, one based on a geostatistical estimator (kriging) and the other on a traditional estimator (inverse distance weighting). Both methods were compared with a contemporary kriged estimate by Mt Leyshon Gold Mines Ltd.

Jan 1, 1993

By J Darbritz

"This paper details the events leading up to a slope failure that occurred at Kalgoorlie Consolidated Gold Mines (KCGM) and the remediation method executed using rope access specialists.n January 2016, KCGM Fimiston Pit experienced a double bench wall failure where approximately 80 000 t of material fell from the wall that blocked access to a ramp and caused minor damage to equipment.The event was triggered by heavy rainfall and occurred along unfavourable eastward dipping structures that lead into weaker shale/porphyry bands, which in turn left more material on the face. A remediation plan was formulated that would allow for the continuation of open pit operations while a full geotechnical assessment of the failure area could be conducted. This was accomplished by means of rope access specialists who abseiled down the wall and blasted off the remaining overhang using a portable drill rig and prepackaged explosives.This paper provides a brief overview of the KCGM operations, how the instability was identified and monitored, details of the failure event, outcomes of the geotechnical assessment and details on the remediation work.Citation:Graf, C and Sullivan, R, 2016. The Journey to Steepening the Pit Slope Angle - Advancing the Effectiveness of Wall Control, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 104–114 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By D Reid, J McKibben, M Noppe

International mineral disclosure standards and guidelines aligned with the CRIRSCO (Committee for Mineral Reserves International Reporting Standards) template were developed to inform stakeholders about the relative accuracy and confidence levels of publicly reported information and to support investment decisions, particularly when advancing projects through different development stages. The traditional stages range from early to advanced exploration, through pre-development (with Mineral Resources and pre-feasibility and/or feasibility levels of study) before the final development stages, where a decision to proceed with construction or production (or both) is made. The traditional definition of Mineral Resource and Ore/Mineral Reserve classification categories and techno-economic study levels (including Preliminary Economic Assessment (PEA), Scoping Study (SS), Pre-Feasibility Study (PFS) and Feasibility Study (FS)) were defined with pre-development project assessment in mind. As such, these definitions are not necessarily well aligned to the reporting structures required by operating mines which need to consider a range of timelines spanning short to long-term operating conditions. However, the same terminology and definitions are used, or expected to be used, by both project developers and mine operators when reporting resources, reserves and techno-economic study outcomes. This paper discusses how various stakeholders in the minerals industry (including competent/qualified persons, mining company leaders, investors, lenders and regulators), generally interpret the definitions of Mineral Resource and Ore Reserve categories in terms of the relative accuracy of the estimates, their link to techno-economic study levels and their contribution to life-of-mine (LOM) schedules. The paper examines the degree to which mining companies recognise, and apply, enhanced operational knowledge to reflect short-term views of the relative accuracy and confidence levels associated with publicly reported Mineral Resource and Ore Reserve estimates and forecasts. Furthermore, this paper explores how this knowledge is applied to support ongoing Mineral Resource, and particularly Ore Reserve, generation and reporting. This paper is informed by public data and responses to an internal survey prepared by the authors and completed in 2021 by several mining companies.

Mar 22, 2022

By W Curlewis, D Hake, Z Cuthbert

The South Island Line (East) will be a medium-capacity railway covering approximately 7 km from Admiralty Station to South Horizons Station on the south side of Aberdeen Harbour in Hong Kong, with intermediate stations at Ocean Park, Wong Chuk Hang and Lei Tung.South Island Line (East) Contract 904 project is located on the island of Ap Lei Chau at the southern side of Hong Kong island and requires extensive construction works to be completed in close proximity to the existing residential estates of South Horizons and Lei Tung. The project also has areas of significant cultural heritage, including 18th and 19th century temples and historical gravesites. Owing to the site access constraints and location for the project, detailed planning and methodology innovations have been required to ensure the most effective and responsible means of delivering the project works. To excavate the tunnels using drill-and-blast techniques in these restricted locations, the maximum instantaneous charge weight that could be fired while blasting was severely limited. To overcome these restrictions, the project team developed and pioneered the use of ‘deck loading’ in Hong Kong to minimise the impact of blasting operations and has successfully implemented double- and triple-deck blasting operations during the completion of tunnel excavation works.Upon completion of the drill-and-blast excavation, the tunnel lining works were completed using both in situ concrete lining with travelling forms and permanent shotcrete works.CITATION:Curlewis, W, Cuthbert, Z and Hake, D, 2014. SIL904 Hong Kong – Drill and Blast Tunnels, station blasting innovations (double- and triple-deck blasting) and lining solutions, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

Alkaline leaching with sodium carbonate solution adjusted to pH 9·5 to 10·0 preferentially dissolves thorium from a mixture of rare earth and thorium hydroxides. Rare earth sodium carbonates form in the alkaline leaching stage.These are converted to rare earth oxides for use as optical and ophthalmic polishing agents. Quadrivalent cerium is extracted under similar alkaline leaching conditions.INTRODUCTIONAustralia has made significant contributions to mineral chemistry and mineral dressing. As often happens with an industrially immature country, research investigations often outstrip the ability or desire of commerce to exploit them. It is wrong to think exclusively in terms of export of raw materials. Imagination assists in developing world trends. The chemical utilization of mineral sands has interested a group of investigators, chiefly at the Commonwealth Scientific and Industrial Research Organization (C.S.I.R.O.) and, more recently, in the mining industry itself. From an international point of view the highlight of this work was Newnham's (1960) process for the separation of hafnium from zirconium. Earlier work at C.S.I.R.O. investigated the chlorination of rutile, zircon, and monazite. Assuming that titanium tetrachloride would be available in large quantities in the post war years, extensive work was done by Kraitzer, McTaggart, and Winter (1948) on organic compounds of titanium. This work led to the development of heat resistant paints, plastic compositions, and improved organic protective coatings that predated overseas work by up to seven years. (Post, Shiihara and Schwartz, 1961; Anon, 1955). Contributions were made to the production of refractory hard metals (Kraitzer, 1949; Kraitzer and Newnham, 1956). Pilkington and Wylie (1947) and Urie (1947) investigated the production of rare earths from monazite by an acid process.

Jan 1, 1963

By H R. Phillips

Fresh air intake in an underground coal mine is of critical importance to the occupational health and safety of workers due to the dynamic, confined and dangerous nature of the mining environment. In most coal mines in South Africa, belt road is not separated from the fresh air intake to the sections. Intake air to coal production faces generally contains dust generated by conveyor belts, transfer points and travelling roads. Long roadways (up to a few kilometres in some of the existing mines) to the coal sections are involved in the ventilation circuits of individual sections. This leads to a progressive increase in the dust levels in the intake fresh air and thus high dust levels in the air delivered to the working sections downstream. In the process of reducing worker exposure to dust in the face area, attention to the monitoring of fresh intake air is generally given a low priority. This paper summarises the intake dust levels measured in selected South African underground coal mining sections over the past five years and its use as a parameter in assessing worker exposure to dust through a newly developed model called the Dust Exposure Level Index (DELI). Based on the measured data of the South African coal mines, the average section intake dust level was 0.78 mg/m3. Approximately 60 per cent of the samples collected for the study have exceeded the 0.5 mg/m3. The intake dust level measured at a longwall face was much higher than in the CM headings. The measured section intake dust levels furnish the South African coal mining industry with the latest depiction of the level of face area dust contamination due to the intake air. Further, this paper demonstrates the use of intake dust level as a parameter in estimating exposure levels of workers, as it clearly plays as a corner stone in effective control of exposure to face area respirable dust. It must be borne in mind that intake dust is a base level to the mine worker exposed to dust without carrying out any additional work in the section. If the intake air is seriously contaminated by airborne respirable dust; then the exposure of the workforce in the section will constantly be elevated by that background dust level.

Jan 1, 2005

By M J. Nugus

The Geita gold mines in north-western Tanzania have produced 5 Moz of gold from an estimated endowment of 15 Moz. They are generally classified as typical Archaean orogenic banded iron formations (BIF)-hosted gold deposits in banded iron formations as described by Goldfarb, Groves and Gardoll (2001); Neall and Phillips (1987); Phillips and Powell (1993) and Neall (1987). The controls on gold mineralisation have been reassessed to conclude that Nyankanga, and we conclude that Nyankanga, the largest deposits within the group, developed during a dynamic and protracted deformation history intimately associated with several stages of hydrothermal fluid flow and alteration. The fluid-induced fractures associated with gold mineralisation are primarily manifested as submillimetre to metre-scale fractures and breccias developed preferentially in rocks that have been previously deformed and altered by silicification or seafloor metasomatism. This realisation detracts from the exploration and mining strategies that would solely concentrate on fluid pathways and associated wallrock alteration and veining solely within the BIFs as hosts for economic gold mineralisation.

Aug 22, 2011

By M.J. Mitchell

Platinum-group minerals (PGM) are recorded from a number of localities along the Waiau River, western Southland, and the south coast of the South Island, New Zealand. At each locality, small amounts of PGMs were recovered as by-products of historical gold mining operations. During the period 1890-1950 an estimated 1000-2000 oz. of "platinum" were recovered from the region, the only area within New Zealand where PGM have been commercially exploited. The PGM suite of southern New Zealand consists of Pt-Fe alloys, IPGE (iridium subgroup, platinum-group elements) alloys, sperrylite (PtAs2), cooperite (PtS)and braggite ((Pt,Pd)S). The composition of Pt-Fe alloy exhibits considerable variation and two compositional populations are recognised. Some Pt-Fe alloy grains are chemically zoned. Iridium is the most abundant IPGE alloy phase and often contains considerable Pt, in contrast to osmium and ruthenium alloys. Cooperite and braggite grains are characterised by extremely low concentrations of Ni. R^~

Jan 1, 1995