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Productivity of mines can be improved by taking fewer, but larger blasts. The initial blasts taken in starting a mining block are restricted by the low amount of void or space to fire into. Block cave mines are using a blasting technique to blast areas that have less than the normally accepted minimum void to establish drawbells for their orebody development. This technique used in block caving mines can be used to improve productivity in mining operations that utilise other mining methods. Some larger blasts have been done in mines, using open stoping methods, which have had void ratios as low as 13 per cent. This has been possible with the use of the explosive gases to transport the broken rock out of the area normally considered to be available to blasts. This trapping of the explosive gases in the broken rock has allowed rock to be moved over 30 m, horizontally, to allow for more void to be available in the blast area. This gives the necessary void ratio allowable to fire larger blasts. This paper will discuss the blasts where this technique has been used in mines to increase the tonnes fired in low void situations. It will also discuss where this type of blasting may improve the productivity of underground mines. Figure 1 shows the how explosive gases have enabled the broken rock to flow out of a draw point without the typical air blast and fly rock that would normally cause a rope suspended sign to be damaged beyond use.

Jan 1, 2008

By Richmond GD

The Hellyer concentrator of Aberfoyle Limited commenced production in 1989 processing a fine grained, massive sulphide ore containing Zn, Pb, Ag, Cu and Au as values. Four concentrates are produced - copper/silver, lead, zinc and bulk (Pb/Zn) - with overall payable recoveries (1991) of 80 per cent Zn, 55 per cent Pb, 50 per cent Ag, 30 per cent Cu and ten per cent Au. Metallurgical development work commenced immediately after plant commissioning, and continues. The flotation response and liberation analysis on a size basis highlighted reagent balance problems associated with tower mill regrinding of sphalerite, poor conditioning of flotation pulps, poor selectivity for fine galena, and insufficient liberation. These were the main causes of values lost to tailings, values reporting to the 'wrong' concentrates and of impurities in the concentrates. Modifications to tower mill regrind circuit operation, and the use of improved conditioning techniques have greatly improved concentrator performance, particularly in the finer (-5 micron) size fractions. Studies of concentrator and laboratory flotation by size and liberation analysis are the basis of diagnostic metallurgy. The techniques used to evaluate the improved concentrator performance are discussed.

Jan 1, 1993

By P C. Hagan

Production scheduling is often reliant on an estimation of a mineÆs trucking capacity. While this mechanistic approach is relatively simple, it often over-estimates actual throughput resulting in under-utilisation of downstream process and a shortfall in revenue. An alternate approach has been developed that recognises the interdependency between processes in the mine production system including materials loading, haulage and crushing. This approach incorporates a heuristic model based on queuing theory that accounts for the variability in performance of individual processes and that this paper presents the results of a study comparing the conventional approach to mine scheduling with a capacity constrained model at a large open cut mine having a truck and shovel fleet. The capacity constrained model consistently predicted a lower material throughput compared to the conventional approach. Differences in throughput between the two approaches were found to increase with loading time, for example when loading time exceeded 3.9 minutes there was a shortfall of up to 40 per cent in estimated throughput. Longer travel times tended to ameliorate any differences. When applied to a mine schedule that extended over a two and a half year period, the difference was equivalent to a shortfall of nearly eight per cent in total material movement.

Jan 1, 2007

By Armstrong ME

The gas bubble energy generated by an explosive plays a major part. in the fragmentation, muckpile movement and damage produced. Previously, the interaction between gas pressure and the rock has been interpreted from a theoretical basis or a qualitative study of breakage mechanisms. A method to measure the fluctuations in gas pressure in rock adjacent to the blast has been developed. This peak pressure will vary with structure, as well as with distance and explosive type. The technique is simple to apply and can be used to observe the flow rate of gas at. varying distances. The apparent velocity of penetration is an indication of whether gas has travelled through pre-existing or blast induced cracks. The technique provides a ?n:eans of determining the suitability of an explosive for a given rock type, depending on the amount of displacement desired. The technique has application in optimir.irig throw blasting and predicting and controlling damage, particularly in highly structured rock masses.

Jan 1, 1986

By Jackson D. G

Iron ore mineralisation in the Paraburdoo environs is known to extend almost continuously over a strike length of 55 kilometres. Six formations of the Mount Bruce Supergroup con- tain high grade mineralisation in varying degrees of importance. Ore is currently being mined from the Joffre and Dales Gorge Members of the Brockman Iron Formation, with smaller, less significant amounts, occasionally taken from the lowermost units of the Weeli Wolli Formation and the upper parts of the Mount McRae Shale. Regional mapping has demonstrated the existance locally of a major unconformity at the base of the Wyloo Group sediments out- cropping south of the minesite. The basal con- glomerates at the unconformity are sometimes mineralised at Paraburdoo. A supergene enrich- ment process controlled by structure, strati- graphy and topography is the only one which can satisfactorily explain the disposition and chemistry of the Paraburdoo iron orebodies.

Jan 1, 1979

By McAllister J

Oxygen was in restricted use at Port Kembla until tonnage oxygen became available for steelmaking in the open hearth furnaces. In adopting the new process various modifications to furnace design and operation were necessary and some of these, including increase in roof height and variation in firing and draft control, are discussed.The design of oxygen lances is also discussed and various steelmakingtechniques considered.Steel production increased with oxygen roof lancing-one- furnace producing 8,507 tons in one week-but new problems, such as rate of refractory wear, and disposal of fumes, were created.Design of future open hearth oxygen furnaces is predicted.INTRODUCTIONIn the post-war era, the availability of "tonnage" oxygen caused a major revolution in steelmaking techniques. Various pneumatic processes showed that steel can be madeat a very fast rate and that oxygen steelmaking can be applied to open hearth furnaces. Methods used are surface impingement with roof lances, bath injection with door lances, flame enrichment with fuel firing, mixed gas and oxygen firing, and enrichment of normal combustion air by oxygen injection into the flue systems.Owing to its previous restricted availability and high cost, oxygen was used in rather small quantities in the open hearth furnaces at Australian Iron and Steel Pty. Ltd.(A.I. & S.), Port Kembla, until about the middle of 1960.At that time tonnage oxygen became available and roof lancing commenced on No. 33 furnace at No. 2' open hearth shop.

Jan 1, 1962

By R Austerberry, S Green

Highly weathered ground, limited collar options and the need to achieve a desired outcome at the lowest possible cost led to the need to adopt a construction approach that had no established design methodology. The newest ventilation shaft at Mandalay Resources’ Costerfield Operations had to be established to a depth of 30 m through poor ground best described as ‘sticky swelling clay’, some of which was contained within an old backfilled pit.The ability to excavate a traditional presink was not possible due to limited space and the introduction of men into the shaft was to be avoided due to the associated safety risks and corresponding increase in cost. Piling in conjunction with raise boring and remote fibrecrete application was identified as a possible solution that could achieve the desired outcome at an acceptable level of risk.Construction of the piles was challenging and required continual refinement until an acceptable level of productivity could be achieved. Limitations on concrete delivery was taken into consideration to ensure hole stand-up time was acceptable and re-drills were not required. The adoption of a set process from alignment, drilling, concrete placement and testing ensured the desired design was achieved. Mine operators should consider the use of piling as a method of shaft stabilisation for the portion of raise bored shaft that passes through the weathered zone.The importance of quality control and attention to detail through the entire shaft construction process cannot be underestimated as issues such as insufficient geotechnical investigation, pile and pilot hole deviation, concrete and fibrecrete quality, as well as delays in the application of fibrecrete can place the success of the project at risk.This paper outlines key learnings from a client’s perspective with regards to the concept, planning, design, execution and completion of a 3.1 m diameter raise bore shaft through both weathered and highly structured ground at the Augusta Mine.CITATION:Green, S and Austerberry, R, 2014. Piling and raise bore construction – key learnings from a client’s perspective, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 35–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

In todayÆs demanding business landscape continual change and technological advancement is a given. With these changes there is now, more than ever, a need to ensure sustainable growth in respect of value protection and value adding whilst meeting the pressures and expectations of the societies in which we operate. Traditionally the management of safety has been a very reactive activity in the business, in some cases seen as an irritation and a disruptive process that demands a focus on preventing reoccurrences. This in turn has focused the measurement of safety performance on a range of lagging indicators û æafter the effect managementÆ. Gaining and maintaining a licence to operate is crucial to a sustainable business but as a prerequisite, organisations need to have a demonstrable ability to manage the safety of their people, as well as mitigating the people risk associated with the business activity. A major focus in the last decade has been on the implementation of enterprise risk management programs, where risk becomes embedded in all business systems and processes and the organisationsÆ genetic make up is programmed to analyse and integrate risk management into all facets of the business activity. The management of safety should be no different. One school of thought argues that there are no new accidents, but rather our inability to learn from the past. Others believe that as long as we have an appetite to achieve the unachievable, we will have to continue to push the boundaries, our safety comfort zones and inevitably take risks. Single reliance on highly evolved technical systems, elaborate processes, highly skilled people, safe equipment and safe work environments have shown one thing û they are not sustainable in providing adequate coverage in the business. In analysing a range of factors associated with some of the worst catastrophes of the 20th century, it can be suggested that they were in fact predictable and inevitable and that an integrated approach underpinned by sound risk management systems could have determined a different result. The key to a sustainable approach in the management of safety requires us to look at a multitude of aspects that collectively allow the performance of an organisation to be predictable. To have certainty in the business activities it is necessary to have controls in place that will mitigate the risks normally associated with unwanted events. It is ensuring that human factors effectively contribute to monitoring the planned approach and being able to safely adjust to any variability. In essence this is having the ability to proactively plan for the longer term. The sentiments articulated by organisational leaders echo that safety management is good business. Surely then a good business is a sustainable business, and a sustainable business is one that provides lasting benefits to its stakeholders.

Jan 1, 2006

By A Turichshev

The synthetic rock mass (SRM) approach for modelling jointed and veined rock has been at the forefront of caving geomechanics research for years. A well-constructed and calibrated SRM model can capture the full rock behaviour at a macroscopic scale. Traditionally, SRM technology employed bonded particle models (BPM) due to their ability to model rock’s response to loading without prior specification of behaviour. The SRM modelling process requires the BPM to simulate intact rock and the subsequent introduction of fractures or veins by changing bonding characteristics between the particles. However, bonded particle materials have difficulty reproducing both the compressive and tensile strengths of intact rock. This and other limitations of BPM have been the driving force in exploring the potential of grain-based (2D) and bonded block (3D) models (BBM).This paper reports on recent work exploring the applicability of both BPMs and BBMs in 3D to the modelling of intact rock. The advantages and limitations of both BPMs and BBMs are addressed based on the results of numerical simulations using the PFC3D and 3DEC distinct element codes. The preliminary results suggest that BBMs are better suited for simulating intact rock behaviour than BPMs. Ongoing work aims to better qualify the applicability of BBMs under different conditions. This has significant implications for our understanding of rock mass behaviour in a caving environment.CITATION:Turichshev, A and Hadjigeorgiou, J, 2016. Simulating intact rock behaviour using bonded particle and bonded block models, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 453–460 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

It is well documented that drill and blast outcomes affect the downstream mining processes of loading, hauling, crushing and grinding but it can also significantly impact on mine profitability via dilution, recovery percentage, lump generation (iron ore), fines generation (coal, iron ore), coal loss and final wall stability. Drill and blast must therefore be optimised to improve the overall profitability via positively impacting on productivity and saleable product generation. It is however, difficult to achieve this because of the complexity of the number of parameters that must be integrated and managed across the entire mine value chain, ie the concept of æMine to MillÆ. This paper highlights, via a simple case study, the need to have a mineÆs drill and blast system both in control (so that it is predictable to a high degree) and with minimal variability (so the design actually makes it into the field). This type of management control is essential prior to optimisation work being undertaken. The æTeam ApproachÆ is discussed to illustrate the methodology of achieving drill and blast optimisation. A case study is presented to illustrate the potential benefits of this approach which in this mine represented a 27 per cent reduction in powder factor with the downstream functions achieving higher productivity with the same or reduced maintenance costs. It is essential for Australian mineÆs to implement the appropriate management strategies and experienced personnel placement to ensure that their mineÆs drill and blast system is correctly managed to facilitate the optimisation of profit. Without this, the Australian mining sector will become increasingly uncompetitive.

Jan 1, 1999

In the 100 years since the formation of The Australasian Institute of Mining and Metallurgy there have been significant changes in all aspects of the mining industry.A number of the changes have been driven by technical evolution or necessity, others have been driven by developments in the application of the products produced from the mining of minerals. Other changes have been driven by shifts in community values.

Jan 1, 1993

Integrated chemical thermodynamic software and computerised databank systems have evolved over the last 15 years. The extent to which these systems have automated thermodynamic calculations relevant to extractive metallurgy is examined. The scope for further automation and the role of the expert consultant is discussed.

Jan 1, 1991

By Polthier K

A short discussion of the salient aspects of a dispersed flow model in relation to the gas flow in blast furnaces is given. The use of the theory in assessing vessel performance is mentioned. Tracer results of a blast furnace (688 m3) from three furnace levels and different radial positions are analysed and results presented as D/ud values. The significance of the shapes of experimental tracer curves are included and comparison is made with results obtained on other furnaces.

Jan 1, 1975

By Albano C, Antila A, Flykt B

A method for relating operating variables and dewatering parameters of Thunes disc filters in the LKAB pelletizing plant at Malmberget in Sweden, via empirical mathematical models is described. Near orthogonal experimental design was used, where all independentvariables were allowed to span over their domain of variation and pseudo-randomly distributed among the experiments. The dewatering parameters are dependent on many variables and instead of using a traditional mechanistic model, an empirical model based on multivariate data analysis was chosen. The way of expressing the relation is by regression coefficients obtained from partial least square regression (PLS). Two empirical models were generated. The models were validated using an extra set of 56 experiments. The dewatering parameters were related to the design variables with few experiments, and user-friendly response surface methodology was used to determine the optimal conditions.

Jan 1, 1989

By Zhou A, Cadogan J. M

Direct reduction of iron ore (DR) is one of the promising technology emerging in the world's steel industry. Kinetics and Mossbauer studies of DR with hydrogen have been carried out at two temperatures of 600¦C and 800¦C in this investigation. The results show that different controlling steps govern the reduction rate at different temperatures. The mechanism was also found to vary during the reduction. The Mossbauer spectra of the samples reduced in various time intervals were studied to determine the phase changes during reduction.

Jan 1, 1997

This paper examines the methods and people required for the evaluation of project or corporate acquisitions. Experience over the past five years has shown that some growth can be achieved by carefully evaluated acquisition of gold projects within regions where the acquiring company has gold processing facilities. Many Western Australian companies have participated in this process and the trend seems likely to continue with a diminishing number of larger producing companies controlling through joint venture or direct purchase of widely spaced ore deposits. In some cases the acquisition may include ore processing facilities, however an increasing number of smaller project acquisitions, involving small open pit gold deposits, which are within trucking distance of the acquiring company's mill. Whilst gold prices remain at the current depressed level we can expect to see this trend continue.

Jan 1, 1989

By Woods PW

Consulting Engineers have been used in the mining and metallurgical industries for many years. The traditional role of the consultant overseas has been one of assisting with conceptual design right through to con- struction and commissioning as well as on occasion acting solely in specialist fields. This role developed because mining companies wished to concentrate on building up the permanent organisation they require to operate their mines and treatment plants without the traumas of increasing staff for the design and construction period and reducing it on completion. In Australia where there have been few individual minerals projects of magnitude (until recently) companies have looked after their own detailed engineering and construct- ion management employing consultants mainly in specialised fields.

Jan 1, 1975

By S J. Woods

As a part of Solid Energy's progressive rehabilitation of the Stockton Mine, it was determined that significant rehabilitation of the existing Mt Frederick Sidecast would be required to ensure the long-term stability of the sidecast. The goal of this rehabilitation is to reshape the existing stockpile into a more stable slope configuration, and the construction of a comprehensive stormwater collection and discharge system. The reconfigured slopes will facilitate the final revegetation of the exposed surfaces and the management of surface and groundwater discharges from the area. This paper briefly describes the specific details of the project and the significance of seismic conditions on the long-term stability of the reconfigured stockpile.

Jan 1, 2003

Mining projects frequently fail to meet their financial objectives. A significant area of poor performance lies in the areas of resource estimation, reserve definitions, selective mining and metal accounting. The processes leading to the exploi

Jan 1, 1998

By Brenchley R

Partitioning behaviour studies for -particles in the 250 to 1,000 micron size range at. the Curragh coal preparation plant are presented. Plant surveys were conducted to compare the partitioning efficiencies of dense medium cyclones and froth flotation. The aim was to assess the potential for improving yield of coal by directing more of the top size of flotation feed material to dense medium cyclones. ovel mass balancing and model fitting NI procedures were used. While flotation offers high yield of low ash particles smaller than 500 microns, dense medium cyclone rejection .of high ash particles larger than 250 microns is superior. These strengths of the two processes are turned to good advantage by the use or desliming sieve bends which tend to perform some density separation on the'size fractions of interest, directing lower ash material to froth flotation than to the dense medium cyclones.

Jan 1, 1987