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By P J. Bangerter, J Pan

Optimising for Net Present Value (NPV) with a strategic optimiser such as COMET, Prober-E, Blaser or Minemax has hitherto lacked a dynamic method for analysing the so-called third-order outcomes (such as Carbon emissions) of optimisation within life-of-mine planning. Optimisation, per se, has natural effects on carbon emissions in a life-of-mine plan. Contemporary strategic planning employs a mathematical optimiser to make sense of non-linear data (ie a block model) and produces a best-NPV optimised mining schedule, within a set of constraints. The very act of optimisation influences emissions, and in a dynamic way.

Aug 2, 2023

By Rashleigh C

The selection and application of an effect- ive firing system first require a clear under- standing of the initiating abilities of the com- ponents in such systems. The conditions under which charges can be prematurely initiated by a detonating cord downline must be appreciated. This is a principal consideration in the design of a successful downline/'Anodet'/primer assembly. The advantages and limitations of an electric and several non-electric initiating systems are explained. The factors which in- fluenced selection of the two most suitable systems for use at Isa Mine (viz. downline/ 'Anodet'/primer assemblies and the reinforced long-lead 'Anodet'-type delay system) are dis- cussed. Blasts are detailed in which each of these has been applied. The initiating design for a hypothetical 2 x 106 tonne blast using electric short delay detonators and multi-channel exploders is presented. In this design, charges in remote blastholes are activated after the detonation of earlier firing charges by protecting the firing lines with sandbags.

Jan 1, 1978

By T. Baker

The Eloise Cu-Au deposit is 60 km SE of Cloncurry in NW Queensland and has a current indicated reserve of 3.2 Mt @ 5.8 per cent Cu, 1.5gA Au and I9g/t Ag. It is hosted by metasediments and metabasic rocks that underwent amphibolite facies metamorphism at 550-600¦C and less than 3.5 kb. Peak metamorphism coincided with the regional D2 event which produced an S2 foliation with north-south strike and variable sub-vertical to steep east or west dip. The deposit is associated with several major shear zones parallel to the S2 foliation. The lodes form part of a large alteration system that is localised by the retrograde shear zones. Homblende-biotite-quartz with minor sulphides occur early in the alteration paragenesis which is overprinted by chlorite-muscovite-pyrrhotite-chalcopyrite ¦calcite+¦nagnetite. The later assemblage replaces the earlier Fe-K alteration as well as Fe-rich metamorphic assemblages such as homblende, biotite and staurolite indicating a post peak metamorphism timing for ore formation. Although replacive textures are the most common, the alteration can display open space infill and brecciation as well as durchbewegung and mylonite textures indicating that mineralisation occurred during ongoing ductile deformation. All these features are crosscut by a later brittle phase of calcite-chlorite-quartz¦pyrite alteration.

Jan 1, 1994

Most publicity about the copper industry nowa- days is focused on the adequacy of ore reserves and on excessive mining capacity. These concerns, stemming from public awareness of actual and poten- tial shortages and oversupplies, relate to production rather than consumption. Perhaps the reason for this one-sided view is that copper is thought of as a commodity which is conspicuously traded in world markets, rather than as one of many industrial materials that serve today's rapidly changing tech- nology. Copper differs from other widely traded com- modities in that its real cost of production has pro- gressively increased since World War II. The reasons for the increase are identifiable by analyzing operations in one of the world's large producing centres, the copper province of Arizona. Another respect in which copper differs from some other com- modities is that increases in demand occur less auto- matically in the case of copper than they tend to in commodities whose consumption is more directly related to population growth. The copper industry's current inability to generate and attract needed investment capital is attributable to these differences between copper and other com- modities; it suggests that the concept of copper purely as a commodity is outdated. The key to the problem is better integration between the activities of copper producers and users. Depending on cir- cumstances, integration takes various forms- for example, investment tied to long-term sales con- tracts between producers in developing countries and consumers overseas; common ownership of pro- ducing and manufacturing facilities in industrialized

Jan 1, 1978

By W Malone, J Garrett

FLSmidth (FLS) has spent the last 15 years, working with customers and engineering houses to deliver innovative improvements in crusher safety, coupled with the latest, maintenance friendly, crusher design. The key focus being to prevent service personnel from working underneath the crusher during maintenance and obviate the need for personnel to be exposed to suspended loads when performing tasks such as, main shaft installation, for example. Improvements include: full top-service capability to ensure the safest and fastest way to disassemble the crusher for maintenance purposes, which also removes the requirement for a service cart; a selfaligning main shaft which ensures remote assembly is now possible, keeping service personnel well out of harm’s way; And rotable shells, or the ability to perform relines off-station, allows for quick shell ‘swap-over’ without the downtime associated with removing, refitting and curing time associated with epoxy backing. The high flow spider improves large material entry into the crusher, reducing blockages and downtime and therefore maintains crusher capacity. Each size of crusher in the range comes with an option to increase the standard feed opening to a larger one if desired to compensate for ‘blocky’ or ‘elongated’ feed material, a common problem for Pilbara hematite iron ores. Power capability has also been increased with a maximum of 1500 kW, to match the higher throughput capacities being achieved. This due to uprated eccentric speeds and larger discharge annulus. Increased eccentric throws and mantle diameters are also now a reality, when compared to more traditional designed gyratory crushers. To keep up with the improved design features of the Mk V, digitalisation has also been upgraded to maximise performance capabilities to ensure that the most efficient reduction and throughput capacities are achieved, whilst utilising the higher powers now available as standard. Condition monitoring ensures that the crusher is at its optimum operating capability by monitoring and adjusting the crusher settings via feedback from additional sensors, ie main shaft spin, temperature and vibration. Camera monitoring capabilities are available as is an advanced oil contamination monitoring system. As a result of the above design improvements, it will be shown that the Mk V range offers benefits such as: enhanced safety features, increased availability, faster maintenance turnarounds, higher power utilisation, equivalent product size at higher throughput capacities and with Remote operation capabilities. All of which result in a gyratory crusher with higher levels of safety and a lower per tonne operating cost.

Sep 18, 2023

By M Coleman

Information is a key ingredient for successful mineral exploration and development. Whether identifying potential exploration localities from a map, interpreting technical reports or searching a register for operators past and present, the common aim is a parcel of information from which the enquirer can make a decision. Traditional information gathering often requires days or weeks of manual research, studying maps, files, reports etc, before consolidating the results into an investment proposal. In recent times, such methods have largely been replaced by Information Technology, making the process much faster, easier and more centralised. However, notwithstanding some very successful technology implementations, the general rush to computerise everything in sight has left many organisations struggling to cope with the management of large volumes of diverse information. Information management is now recognised as the most important factor in determining the success of information technology implementation. The Northern Territory Department of Mines and Energy (DME) has established a detailed information management strategy to underpin the rapid advance of computer technology within the organisation. A broad base of timely and reliable information is gradually becoming more accessible. It is envisaged that the availability of combined spatial, textual and scientific information will provide a sound basis for decision-making within the Department and the mining industry at large. Although information held by DME will be available at all times (24 hours on-line), its security and confidentiality will be guaranteed. The production of the DME system is aimed at satisfying the corporate objective to facilitate and promote mineral exploration and development. This paper outlines some current developments in the system.

Jan 1, 1994

By Baafi EY, Appiah HK

The Prestea Goldfields Ltd of Ghana, West Africa has produced over 170 t of gold with average grade of 11 g/t since 1912. The deposits occur in a wide shear zone which closely follow the Birimian-Tarkwaian contact. Both the Birimian and Tarkwaian systems are of Precambrian age. Underground exploration is carried out to delineate ore bodies by means of AX size diamond drilling at 50 m sampling intervals. After the orebody has been delineated, development work is carried out by exposing the gold reef. Channel sampling is then carried out at about 3 m intervals in both the stope and stope drives. A channel sample length is commonly 0.6 in, but may vary depending on physical characteristics of the reef. The values of channel samples are linearly combined to obtain the average reef or slope values and/or widths of the exposed sections. The sampling practice and methods of improving the efficacy of sampling at the mine are described.

Jan 1, 1976

By Nixon TR

The Australian Coal Industry Research Laboratories Ltd. (A.C.I.R.L.) MINVENT computer program can be used to simulate existing and projected colliery ventilation requirements. New collieries can be planned using a database of ventilation parameters which were ascertain- ed by A.C.I.R.L. surveys at selected collieries in N.S.W. and Queensland. Several techniques are used in both the formulation of the database and in the evaluat- ion of a ventilation system, prior to analysis by the MINVENT program. The analysis of a ventilation system requires the measurement of air quantities, pressures and hence airway resistances. All resistances are calculated at standard air density of 1.205 kg/m3. Air densities are derived from barometric pressure and wet and dry bulb temperature readings. Airway frictional and shock losses, leakage through stoppings and overcasts, flow of air through regulators, face resistance and resistance of anomalous ventilation features are related to the typical Australian measured data presented.

Jan 1, 1983

By Rosmus P

Improper use of auxiliary ven- tilation units during heading operations may often result in the appearance of hazardous methane accumulations. This is the case especially when roadways are ventilated by a combined system with a short sucking pipe at face end performing as the dedusting installation. Uniform air inflow to the face end facilitates sucking off the dust clouds and creates conditions favourable for formation of local methane accumulations. The highest methane concentration occurs in the cutting zone between the rock cut and the pipe inlet, under the roof and by, the sidewalls. Permanent monitoring of methane concentration at face end employs methane sensors. The most important are: one on the road- header's boom behind the cutting head, and one at the air outlet from the dedusting installation.

Jan 1, 1988

By M English, M Yumlu

At times of high metal prices, mining projects that have previously been put into the ætoo hard basketÆ are now being more closely examined. Typically these projects include the potential recovery of small mineable tonnes with high contained metal values and often with poor ground conditions. For many underground mining projects, the drift and fill method is viewed as a high-cost method and a æmethod of last resortÆ. As a result the method is not well known in Australia and it is the authorsÆ view that the method is under utilised. The drift and fill method can be applied to a variety of underground mining situations and is a preferred method for some orebody geometries and where ore recovery is viewed as a key to project success. This paper examines some of the critical mine planning and backfill issues involved with the drift and fill mining method.

Jan 1, 2008

By O A. Aladejebi, S Mitra, T Singh, D O’Dea, S, T Honey

Granulation of the iron ore blend and the additives is the foremost step in the agglomeration of iron ore fines to achieve a permeable bed during sintering, which is crucial for sinter productivity. This study investigated the granulation of four types of blends to determine the impact of granulation on bed permeability. The blends were granulated in a rotating drum at various moisture contents and their JPU permeability was measured at each moisture content in a permeability pot (diameter 95 mm and height 500 mm) at various flow rates. Several independent experiments were carried out to investigate the changes in permeability when mixtures of different particle size range (-1 mm and +1 mm) were introduced into a packed bed with a larger particle size range (-6.3 mm to +4.0 mm). The results revealed that the addition of particles in the -1 mm size range had a more pronounced negative impact on permeability compared to particles in the +1 mm size range. This can be attributed to the relatively higher energy losses (mainly inertial) associated with the presence of -1 mm particles in the mixture. The findings were used to quantify the granulation process based on the -1 mm particle size fraction in the granulated mix and their utilisation (denoted by UI-1 mm). For achieving optimal permeability in a specific blend, it was found that a UI-1 mm (utility index of -1 mm particle size) ranging from 0.82 to 0.92 was required. However, exceeding a UI-1 mm value of 0.95 resulted in weaker granules prone to deformation and led to decreased bed permeability. The study also showed that the UI-1 mm was highly dependent on the water addition per kg of -1 mm in dry feed and suggested adding ~80 to 110 mL of water per kg of -1 mm in dry feed to attain the best possible permeability. Additionally, the research proposed a mechanism involving the melting of granules at high temperatures and highlighted the influence of -1 mm particles on bed permeability during the sintering process.

Sep 18, 2023

Pbo activities have been measured in conventional blast furnace and direct smelting type slags at 1200¦C. Much higher activity coefficients than previously measured have been obtained and attributed to interactions between iron and lead oxides. The behaviour of PbO in the two types of slag reflects their relative silica contents. Simple equations derived from mathematical modelling work are presented for the prediction of Pbo activities in complex industrial slags.

Jan 1, 1984

The constraints in university courses are lack of hours, high cost of scientific equipment, and poor availability of suitably experienced staff. These have forced the balance away from practical work and towards more theory. Labelling of individuals as either practical, or academic, does not help the inter- change of staff between industry and univer- sities that is necessary to balance idealism and realism. Practical men who do return to universities may lose seniority and find that industry is reluctant to have them back. Academics who specialise too long may concentrate on their research to the exclusion of basic material. It is difficult to operate pilot scale plants in universities because of lack of time, and obsolescent equipment. Small grants from industry might enable tests to be run in research laboratories such as at C.S.I.R.O.. Within universities there may be a need for greater interchange of students among depart- ments, aided by the absence of weighted student unit measurements, as suggested by Aus.I.M.M. and A.M.I.C.

Jan 1, 1984

By Agrawal A, Joshi A

Mochia mine, in culmination of depillaring operations, fired India's largest underground pillar blast consuming 145 tonnes of explosive and yielding 0.55 million tonnes of ore in June 1994. To protect main mine structures (situated at a distance of 250 to 350 m from the blast site) from resultant ground vibrations, the charge per delay was restricted to 2300 kg. The post-blast observations revealed that no damage was caused to these structures. However, the damage assessment survey of the mine workings situated in close proximity revealed a general trend in consonance with the distance from the blast and found to be well correlated with peak particle velocity.

Jan 1, 1995

Underlain by and intruded into the sedimentary rocks of the Transvaal Supergroup the Bushveld Complex is the largest known layered intrusion in the world and contains one of the richest ore deposits on earth. It has been the world's major source of Platinum Group Metals (PGM) since the mid-1900s with Chromite and PGMs the two most economically important components of the Bushveld Complex. The lower group (LG), within the critical zone, consists of seven chromitite layers and it is within this sequence of chromitite layers, the most important target of the lower chromitite group is found, ie the LG6 chromitite unit. The LG6 chromitite unit consists of a chromitite duplex composed of the lower LG6 chromitite layer (Steelport seam), averaging 1 m thick, overlain by a 0.66 m waste parting and a thin 0.34 m thick LG6a chromitite layer (leader layer).Two mining methods are commonly applied in the Bushveld Complex to extract the LG6 chromitite layer package. One method consists of footwall development utilising rail bound equipment to gain access to the orebody and then extracts only the LG6 chromitite layer by means of hand held rock drills and scraper winches. The second method is the use of mechanised equipment to access the orebody on the plane of the ore utilising bord and pillar mining method, which extracts the full mineral resource, ie the LG6 and LG6a layers. Conventional narrow vein stoping is often selected due to the large conventional mining skills base found in South Africa, the perceived cost and dilution implications of utilising mechanised equipment, and the difficulties of using mechanised equipment at dips above 12¦. The driving factor for mechanised mining is the perceived ability to access the orebody quickly and inexpensively, and extract the entire mineral resource package (LG6 and LG6a) while limiting capital expenditure and improving safety.This paper investigates these two commonly applied approaches, highlighting the benefits and problems associated with the two approaches. Comparisons will be made of the two mining methods and recommendations given for the mining engineer to consider before selecting the appropriate mine design.

Dec 6, 2010

An analysis of pumping figures suggests that there are two distinct styles of water inflow patterns in Zambia's mines. Carbonate hosted orebodies (Kabwe and Nampundwe) display a characteristic seasonal variation in water inflow with peak pumping showing a short time lag with respect to the rainfall pattern. Aquifer characteristics are controlled by secondary, weathering enhanced, near surface phenomena. Non-carbonate hosted orebodies such as those of the Copperbelt (Konkola and Nkana) occur in successions of highly variable lithology and consequently there are stacked aquifers of variable character. Inflow of water does not display seasonal variation. The major factors affecting the amount of inflow are the structural setting, the geometry of the orebody and the local lithostratigraphy. Thus the Konkola orebodies which occur in a saddle shaped open ended basin result in what is probably the wettest mine in the world, pumping some 376,000 cubic metres of water a day.

Jan 1, 1988

The winning and upgrading of mineral raw materials necessarily includes size reduction, which serves the liberation and production of marketable products from highly valuable and bulk materials. For crushing, the following factors can be duly accounted for depending on material type and the selection of the suitable machine: ò producing a particular size distribution, ò producing a particular grain shape, ò selective comminution, ò gentle comminution, and ò producing a size range required by a specific process and/or for a specific product.

Jan 1, 1993

A very wide range of technologies are utilised in the mining and processing of ores and a great deal of effort is expended in the development of ænew technologiesÆ to improve mining performance and economics. Traditionally, technology and people have been treated as separate aspects of an operation, when in fact they are inextricably linked. The successful implementation of new technologies is entirely dependent upon the actions, enthusiasm and skills of people, both as individuals and working in groups. This paper discusses the role of technology in mining and how new technologies are implemented by the industry. The paper argues that existing technologies have not been fully or adequately utilised and that effort should be re-focussed on the implementation of technologies that have been taken for granted for many years. The need for greater emphasis to be placed on the management of the human-technology interface is discussed.

Jan 1, 1998

By R H DAVIES

Peak Gold Mine is a new gold and base metal mining project being developed by Enterprise Metals (a 100 per cent subsidiary of CRA) at Cobar in the centre of New South Wales. The Cobar district has a long history of copper and gold mining operations stretching back to the 1870s. Extensive gold and base metal mineralisation was discovered at the Peak in 1981 below a series of gold mines which had been active around the turn of the century. Evaluation of the deposit through the 1980s led to CRA's decision to develop the project for production at a capacity of 450 000 tonnes per annum in late 1992. The project has been developed with a green fields approach despite the long history of mining in the local area. This approach has lead to several innovative ideas being trialed at the site which are expected to result in the operation being a low cost producer of gold and base metals.

Jan 1, 1992

By D MacKay

The Mt Wright Project is located near the town of Ravenswood in North Queensland and is operated by Carpentaria Gold – a wholly owned subsidiary of Resolute Mining Limited. Underground Development of the current Mt Wright orebody commenced in June 2006 and the first production ore was brought to surface in June 2007. The orebody is a rhyolite pipe containing fine-grained disseminated gold in a granite host rock. Ground conditions tend to be good to excellent throughout development, with some minor deformation experienced when stope-sized excavations are formed. The mine commenced as a sublevel open stoping (SLOS) operation with the intent to utilise development waste to back fill isolated upper level stopes while developing to the bottom of the known orebody. The mine plan intended to commence production with a bottom-up primary/secondary stoping retreat through the main orebody utilising cemented fill. Some challenges were faced during the initial production phase that included:•Ongoing underground diamond drilling and updating of the block model resulted in some issues reconciling the grade control results to the resource model. This was primarily due to the high variability of grade which in turn caused difficulties in accurately identifying areas of low and high-grade.•The cost of establishing and operating a cemented fill plant to achieve the planned extraction sequence of the orebody had increased significantly beyond initial estimations.•Geotechnical conditions such as stress orientations, ground behavior and response to the forming of excavations learned through the mining of the upper level stopes were different to the assumptions made during the initial design.A number of in-house and external reviews of the mining method were completed which has resulted in a revised mining plan. This paper will summarise the challenges faced and the implementation of the mine plan to date.

Mar 21, 2011