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By Longworth C. R

This paper descrioes a case history of a coal mine which developed un'tahle roof conditions due to mass sliding of the overburden strata on a claystone band within the coal seam. The sliding is believed to have been initiated by stress relief associated with the removal of overburden alongside the entry portal of the underground workings. Once in motion, the roof block was kept moving by bulking due to roof collapse in the normal underground goafing operations. Control measures in the form of an earth and rockfill buttress against the entry portal and a sequential mining plan to create goaf areas alongside the entry portal have been initiated to attempt to limit movement. The operation has been continually monitored and a gradually decreasing pattern of movement is being re, orded.

Jan 1, 1981

By S Smith

Several styles of copper (Cu) mineralisation are present at Sepon. Large tonnage, low grade skarn and carbonate replacement massive sulfide mineralisation occur within the metamorphic aureole of Permian-aged rhyodacite porphyry intrusions (RDPs). During exhumation and supergene weathering, this primary mineralisation has been upgraded to form high-grade chalcocite enriched zones up to 50 m thick, which comprises the bulk of Cu resources currently being mined at Sepon. Groundwaters remobilise Cu to form exotic accumulations of malachite that are locally hosted in irregular karsts in carbonate rocks, found up to 1000 m from source mineralisation. Khanong is the largest Cu deposit and recent discoveries have been made at Thengkham South, Thengkham North and Phabing. All deposits have formed by similar processes of mineralisation. However, all differ due to local variations in host rock lithology, structural setting, and hydrological conditions. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By M Brewster

Goldfields Abosso Goldfields Limited (AGL) is a Ghanaian registered company that owns and operates the Damang Gold Mine. Gold Fields Ghana Holdings Limited holds a 71.1 per cent interest in AGL. The Damang concession held by Gold Fields Ghana Holdings Limited covers a total area of 271 km2 located 40 km north of the town of Tarkwa in the south-western part of Ghana. Gold Fields as a company registered on the New York Stock Exchange is legally obliged to be SOX (Sarbanes-Oxley). Sarbanes-Oxley Section 404 (SOX404) is on management assessment of internal controls. The Mineral Resource Management (MRM) function of AGL manages three Prospecting Licenses and two mining licences. At least ten pits/prospects are scattered along the two limbs of the Damang Anticline and have two main types of mineralisation notably Paleoplacer and Hydrothermal. Thus SOX404 procedures are put in place to treat each mineralisation type in the best way for reliable resource outputs and estimates. Generating auditable resources for AGL is a prime but most important function of MRM. Thus important checks are built and designed to ensure that all relevant geological and geostatistical inputs conform to procedures outlined under SOX404 requirements. More importantly sign offs are designed to ensure that technical personnel involved in all aspects of resource and reserve generation are satisfied and can be held accountable.

Jan 1, 2007

Multi Torque Industries and Jadefoil have developed a safer, more efficient method of explosive protection, retention, placement, and constraint. In particular, this refers to advancements in airbag technology, where the system will offer an alternative to conventional gasbags and decking methods to provide a far more controlled and safer working environment. Airbags have provided operator control and reliability which has not until now been possible in this type of application. The benefits have been noted by current users and the advantages have provided an increase in productivity and significant savings in explosive waste. Obvious problems with gasbags lie in their instability in hot conditions where the danger is associated with gas canisters exploding with great force posing a significant risk to operators. Other problems associated with the decking systems currently on offer is the lack of versatility and operator control. The airbag systems give the operator full control to guarantee accurate placement, assured retention whilst boasting a quick operation of less than a few seconds for conventional void blocking, decking and plugging. One of the main advantages of the airbags is that the operator has full control over placement and retention force, therefore in wetter conditions where slippage can be a problem extra air can be added at the operatorÆs discretion to ensure a sufficient grip. Technical calculations coupled with experimental testing have demonstrated that an airbag will support the weight of a 30 m water column in an 89 mm hole at an initial bag pressure of 5 psig. Applications are increasingly growing whilst more customers embrace their use. Advancements such as the ability to deck in overhead holes, block voids in overhead holes at any depth, explosive retention in very wet conditions, longhole stabilisers to prevent hole closure and concertinaed liners reflect a dynamic potential for new technologies. All of these applications provide a decrease in explosive waste, an increase in operator safety, an increase in explosive protection, and an increase in productivity.

Jan 1, 2004

By D Gericke, R Cooke

This paper presents an assessment of the status in design and operation of deep level backfill distribution systems by referring to case studies and practical experience. The improvements in design and operation of the systems can largely be attributed to an improved understanding of slurry flow behaviour and a corresponding integrated design approach that includes slurry flow modelling, system design and application of the latest technology. The conclusions summarise the lessons learnt from such case studies and stresses the importance of design reviews and audits of existing systems as a means to ensure that the mistakes of the past are not repeated in the future.

Jan 1, 1998

By M I. Pownceby, N A. S Webster, J Manuel, N Ware

The properties of iron ore sinter – commonly defined by measures of tumble strength, reduction degradation and reducibility – have a major impact on blast furnace performance. These properties are largely influenced by raw material properties, in particular the bulk ore composition. Despite this importance, there is a lack of quantitative data on the impact of ore chemical composition on iron ore sintering. This is surprising since the levels of Fe, SiO2, Al2O3, P, MgO and other elements, together with the nature of the minerals in the fine ore, play a major role in determining the abundance and type of high-temperature bonding phases that form during sintering. It is the abundance and nature of the high-temperature bonding phase(s) that directly influences sinter quality. This study combines in situ diffraction experiments in model sinter systems with laboratory-based compact sinter tests using natural ores to examine the links between iron ore composition and sintering temperature and their effects on standard metallurgical sinter quality test methods. Results help to establish the critical compositional and thermal parameters that control the bonding phase chemistry, which in turn influences the physical characteristics of the sinter matrix. This information should enable operators to predict optimum sinter operating conditions based on the initial chemistry and mineralogy of the iron ore fines and recognise the chemical modifications to the original iron ore fines required to produce high-quality iron ore sinter.CITATION:Pownceby, M I, Webster, N A S, Manuel, J and Ware, N, 2015. Iron ore geometallurgy – examining the influence of ore composition on sinter phase mineralogy and sinter strength, in Proceedings Iron Ore 2015, pp 579–586 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By R Vleggaar

In addressing a short-term operational need for the relocation of a tailings storage facility reclaim pond, a mine has achieved a host of water management objectives. Through effective planning and adoption of a strategic æwhole of mine lifeÆ approach, the mine has achieved significant environmental, social and economic benefits. A review of all water management aspects across the site identified a host of other interrelated water issues and concerns which, if dealt with individually, would prove too costly for individual operational departments. When considered as a whole, however, the issues became opportunities and provided the stimulus for integration of the site water management system. The development of site water and solute balance models provided the tool by which a number of water management options/strategies could be evaluated. The conceptual design and costing of the proposed water infrastructure further facilitated the evaluation of the multiple benefits to be gained from each option. A business case could then be made to mine management for the preferred option. The recommended water management strategy finally recommended to the mine not only provided a tailings storage facility (TSF) reclaim pond, but also provided for:increased wastewater recovery from the TSF, the capture of all waste rock dump run-off, additional water harvesting from local creeks, increased wastewater reuse, improved environmental water management, infrastructure that could be used by the local community after mine closure, and overall cost savings. This paper illustrates how effective water management planning can provide both short-term economic and environmental benefits, as well as long-term social benefits.

Jan 1, 2006

As near-surface underground mines progress deeper, the inevitable question is whether to convert from truck haulage to shaft hoisting. The desire to defer capital expenditure frequently delays investigation of the shaft option, or deferral of a decision to start shaft sinking, unless the shaft option is clearly significantly better than trucking. By the time increasing depth makes trucking uneconomic, there may then be insufficient resource remaining to justify a shaft, and the mine must close. However, had the shaft been built earlier, its lower operating costs would have permitted the mine to continue to greater depths. This paper presents a methodology for investigating the shaft versus trucks decision. As well as the typical analysis of which option is preferable at the time the analysis is conducted, the process presented illustrates how the timing of the decision to sink a shaft is critical. The paper shows how to identify the latest date at which the decision to sink a shaft can be made, after which time the shaft option will not be economic. It also illustrates how to assess the resource that may be required to justify the shaft. Considering this in conjunction with the latest decision date, implications for the companyÆs exploration program are discussed.

Jan 1, 2005

By C F. Nichol, L Smith, R D. Beckie

A better understanding of the hydrogeology within mine waste rock and cover systems is essential for the quantification, prediction and prevention of metals loading to the environment surrounding waste rock piles. The effect of surface condition on the internal flow mechanisms within an intermediate-scale constructed waste rock pile is being investigated at the Cluff Lake Mine, Saskatchewan. Changes in the water balance, the outflow distribution and water residence time have been observed in the waste rock pile following successive modifications of the surface condition. The three year old, run of mine, free-dumped surface was ripped to a depth of 30 cm to 40 cm, and levelled in October of 2001. In August 2002, a 10 cm to 15 cm cover of compacted waste rock was placed on the pile. Outflow, precipitation and run-off data collected during natural and artificial rainfall events have been used to quantify the maximum infiltration rate, and the spatial pattern of discharge and cumulative volume of water that infiltrated into the waste rock under each surface condition. Infiltration data together with the outflow data provide a basis to address the residence time of water within waste rock and the dominant flow mechanisms for different surface conditions. With a free dump surface spatially distinct wetting fronts are observed at the base of the pile that vary in flow rate by an order of magnitude (measured at a 2 m by 2 m scale) and in time by up to a week. Following ripping and levelling, similar cumulative outflows were observed, but the magnitude and arrival time of wetting fronts changed across the pile. A decrease in outflow volume, a decrease in infiltration volume, a two-fold increase in the response time of wetting fronts and a more spatially uniform distribution was observed following placement of the compacted surface layer. Based on preliminary data, the internal structure appears to be the dominant factor controlling outflow variability.

Jan 1, 2003

South Africa is a semi arid, water scarce country that has undergone recent major political and social transformation. This transformation has ensured that water management has become a primary environmental concern in the South African mining industry, raising the status of water from an ancillary service to a fundamental factor in mine planning. The coal mining industry has been involved in the development of integrated catchment management plans since the late-1980s when a series of initiatives commenced in catchments where collieries operated. The plans focused attention on water supply and water demand management, the equitable access to water supplies, and intersectoral approaches to decision making, before the promulgation of new legislative and policy frameworks. Development of an integrated watershed management plan for the Olifants River basin, located in the Mpumalanga province, commenced in 1990. The Olifants River is an international river basin of 54 570 square kilometres and shared by South Africa and Mozambique. The upper watershed, locally called the Witbank Dam catchment, will be the focus of this paper. It has an area of 3400 square kilometres and is the major coal mining, power generating, and maize-growing region of the country. The processes embodied in the integrated watershed management plan had no formal guidelines but rather developed in an ongoing fashion over time. The plan commenced with a situation analysis involving the major stakeholders that identified principal technical shortfalls. These shortfalls were investigated under the guidance of multisectoral committees. The Olifants River Forum was started to extend awareness of the initiatives on an informal level throughout the whole watershed. The results of the investigations enabled water quality guidelines to be established for the upper catchment. To achieve the guideline levels additional initiatives were developed including a scheme to manage mine water discharges into the river system, the development of a standard four-step water management process, investigation and development of innovative mine water treatment processes, specifically sulfate reduction technologies, the use of gypsiferous mine water for irrigation, river and dam hydrological models, groundwater models and biomonitoring. Significant outcomes from the process have been achieved including the improvement in water quality in the Witbank Dam catchment. Equally significant have been the development of partnerships between businesses and between businesses and the community specifically in the use of mine water for irrigation. The plan realised a number of requirements for success including, the development of trust, openness and transparency with information, the essential need for consultation and negotiation and the involvement of third parties to validate information. The future still holds the potential for disputes between upstream and downstream water users but understanding, transparency and accountability between all players have, and will in future, enable the matching of the increasing demands on a scarce water resource to the needs of all.

Jan 1, 2003

This paper describes preliminary research on the application of Markov Decision Processes (MDP) to Real Option Valuation (ROV) and the optimisation of mine scheduling. The MDP framework is a novel approach to option valuation and scheduling in mining operations. A learning agent is introduced into the valuation process of an open pit, where prices and block ore grades have probabilistic values. The prices are modelled using a mean reverting diffusion process and the block grades using sequential Gaussian simulation. The agent is asked to learn which production parameters should be used in order to maximise the overall value of the project. The introduction of the agent permits a real option approach to mine valuation, such that the value associated with the robustness of a design to uncertainty can be measured. A simulated example is used in which there are ten blocks to be extracted under conditions of grade and price uncertainty. Using policy iteration, an optimal policy is generated and the value of production options is found. The potential financial gains from applying MDPs to mine valuation and optimisation are substantial and warrant further investigation.

Jan 1, 2007

By Arit I, Adisoma G

General Limit Equilibrium Method (GLE) and Janbu's Generalised Procedure of Slices (GPS) are two limit equilibrium methods in slope stability analysis which satisfy all equilibrium conditions. Numerical difficulties associated with these metho

Jan 1, 1998

The microstructures exhibited by ilmenite in its association with other oxide minerals have been the subject of a number of papers, the most comprehensive of which is that by Ramdohr. The following observations in some degree extend his conclusions. They are based upon a study of about sixty specimens of "massive" ilmenite and titaniferous ores from a number of wIdely 'scattered Australian localities. Specimens of this character proved much rarer than was expected. The collection was gathered together through the generous aid of the University Geological Departments, Geological Surveys, and Natural History Museums of the several States of the Commonwealth, all of which contributed such specimens of local origin, as they possessed. Special thanks are due to Dr. E. S. Simpson, of Western Australia, who made available several highly interesting specimens, together with his...

Jan 1, 1938

By Denby B, Hollands R. Schofield D

Surface mines are in operation worldwide, the vast majority employ large haul trucks for the transfer of material both to the outside world and around the site. The sheer size of these trucks and the operating conditions means there is a high

Jan 1, 1998

Bureau of Medical Inspection, Broken Hill, New South Wales.INTRODUCTIONFor a considerable time it has be3n realised that the pathological changes produced in human lungs by the inhalation of free silica varied, not only according to the amount of silica inhaled, its particle size and the period during which it was inhaled, but also according to other mineral elements which might be admixed with the fine silica dust and inhaled along with it, or inhaled subsequently to the silica containing dust. It was observed that, in many instances, these admixed dusts tended to inhibit the action of the free silica in causing injury to the lungs, as well as the development of certain complications, whilst in other cases it was felt that certain substances could actually accelerate the tissue damage caused by the silica.A fresh impetus to the problem of the prevention of the development of silicosis was given when, in 1937 and 1939, Denny, Robson and Irwin published papers entitled "The Prevention of Silicosis by Metallic Aluminum." Working at the same time at the Saranac La.boratory, and quite independently, and using a colloidal aluminum hydroxide, Gardner arrived at the same conclusions as Denny, Robson and Irwin, namely, that in experimental animals the development of silicotic changes could be prevented if eithertogether with the silica, or subsequent to its inhalation...

Jan 1, 1946

By Jacobsen L. K, Gross K. B

This paper, describing milling practice at Mount Isa Mines, is one of a series covering milling methods and costs that is being published by the Bureau of Mines, United States Department of the Interior.The Mount Isa concentrator began operations in May 1931, by treating a mixture of oxidized and sulphide ores. Since March, 1935, only sulphide ores have been milled; this change involved major alterations to the flow sheet. The maximum capacity on mixed oxide and sulphide ores was 2,650 tons per day; the present capacity is approximately 1,880 tons of sulphide ore per day. The installation of additional Grushing, grinding, and flotation equipment when completed early in 1939 will increase the maximum capacity of the concentrator to 2;240 tons of sulphide ore daily.All tonnages in this paper are expressed in tons of 2,000 pounds, gallon measurements in terms of Imperial gallons of 277·41 cubic inches, and costs in dollars at the rate of $4 United States currency to the Australian pound.

Jan 1, 1939

By Nichol R

- PART A The Hoppers Crossing Pumping Station is one of the principal components of the Western Trunk Sewer Project which replaces the 90 year old Main Outfall Sewer and will convey 60% of Melbourne's sewage flow from Brooklyn to the Board's Farm at

Jan 1, 1987

By Woodcock J. T, Rummel P. H, Sparrow G. J, MacRae C. M

A rapid automated search method, developed for the location of native gold grains in polished sections with a scanning electron microscope (SEM), has been extended to locate platinum group elements (PGE), in particular platinum and palladium, and their minerals down to 1 ¦m in size. Problems associated with the search for PGE minerals are discussed and examples of PGE minerals located with the facility in drill core sections, crushed ores, and metallurgical test products are given.

Jan 1, 1991

The mobility of radionuclides released into aquatic, terrestrial and subsurface environments by mining, industrial processes is an area that deserves significant scientific attention. The presence of microorganisms in these environments can influence the transport of radionuclides. Free-living microorganisms constitute mobile suspended particles that may have a radionuclide sorbing capacity higher than that of the environment. Radionuclide transport will then proceed faster with than without microorganisms. In contrast, if the majority of the microorganisms are growing in biofilms on surfaces, transport of radionuclides may be reduced. Microorganisms can directly sorb radionuclides either within the cell structure or on the cell wall. Radionuclides could also be sorbed by minerals precipitated by microorganisms. Microorganisms produce complexing agents that can influence radionuclide mobility. The involvement of microorganisms in biogeochemical processes is related to their ability to include various chemical elements and their combinations into biochemical redox reactions. Microorganisms can alter the extent of radionuclide oxidation that results in their deposition as a result of the formation of insoluble forms. Some studies have shown the bioremediative potential of stimulating reducing bacteria to use some of the soluble radionuclides as electron acceptors and thus precipitate them out of solution. The microbial involvement in providing a barrier for radioactive element migration (uranium, technetium) and the formation of ores (eg uranium) has been justified. The mediated impact of microbial activity on radionuclide migration occurs through its effect on the ambient geochemistry by geochemical speciation changes, pH changes and changes to the ambient redox potential. As the mobility of many radionuclides depends on the pH and redox potential of the environment, these microbially mediated geochemical changes can influence radionuclide migration through changes to both the dominant radionuclide species and mineral phases.

Jan 1, 2004

By Evans A. F

Arising out of the increasing demands for efficiency in modern ore-dressing operations has grown a requirement for fuller knowledge of the characteristics of the ore treated. In part, this is being met by improved methods of study of the mode of occurrence of the constituent minerals, and of the intricacies of their physical relationships.A typical instance of the need for such a study is the presence of some undesired mineral in a flotation concentrate or tailing, which may be due either to mechanical association through insufficient grinding, or to incomplete separation in the flotation operation.Again, with modern practice in fine grinding, which often requires that from 70% upwards of the ground ore shall pass a 200-mesh screen, it is obviously impossible to obtain data on comparative grinding efficiencies, for instance, unless there is adequate knowledge of the size-composition of the material passing the finest available screen.Studies like these can be made satisfactorily only after size-separation (which may be carried out conveniently by elutriation) and by actual visual examination with the aid of a microscope, and the minute size of the mineral grains to be examined has necessitated the development of a new technique of sizing and microscopic examination.

Jan 1, 1932