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By R J. Romañach

The theory of sampling (TOS) is now followed in the development of near infrared (NIR) spectroscopic methods for the pharmaceutical industry. TOS has been the guiding light for a two-step approach for spectroscopic composite sampling available for the development of real-time analytical methods for particulate-based industrial processes. The two-step spectroscopic sample composite has been used in the development of process analytical technology (PAT), an important regulatory initiative to improve the quality of pharmaceutical products. The two-step sample composite approach overcomes the low sample volume analysed by PAT methods; one of the key limitations to PAT implementation in the industrial production of particulate-based materials.PAT methods need to be validated demonstrating their accuracy, precision, specificity and robustness. TOS provides a deeper understanding of these validation studies which involve discrete particulate material. The validation of PAT methods is now being performed considering both sampling and analytical errors, while practically all previous method validations only addressed the total analytical error (TAE) of these methods. This has been a crucial impediment for the field of chemometrics as well.PAT is a key element of continuous manufacturing (CM) processes, which are considered an emerging technology capable of increasing the flexibility, agility and robustness of pharmaceutical processes while reducing their costs. The outflow of the continuous process is a 1D lot, and variographic analysis has been shown to discern process variation from sampling and analytical errors in pharmaceutical CM processes. Thus, variographic analysis is a process improvement tool with significant potential for improving CM processes. The possibilities for improving pharmaceutical manufacturing are enormous.CITATION:Romañach, R J, 2017. Theory of Sampling – from missing link to key enabler for process analytical technology, in Proceedings Eighth World Conference on Sampling and Blending , pp 63–68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

The design and operating characteristics of the hydraulic cyclone elutriator were described in detail by Kelsall and McAdam (1963), and the method of operation of the commercially available version, the Cyclosizer, is described in the manufacturer's pamphlet (Anon). Complete details of the operating procedure are given in the relevant operating manual (Anon, 1964).The cyclones which form the basis of the Cyclosizer (Fig. 1) under normal operating conditions produce typical cut sizes of 44, 33, 23, 15, and 10 µm for cyclones one to five respectively for material with a specific gravity of 2·7. At the end of the selected elutriation period each sized fraction is discharged and collected for subsequent assay or analysis but all material rejected by the fifth cyclone (e.g. minus 10 \lm quartz) normally passes to waste. When this material is needed for separate study, although its amount and average analyses can be calculated by difference, it may be necessary to collect more than 250 I. of very dilute suspension, flocculate the solids, allow to settle, and decant off the supernatant liquid.This procedure is cumbersome and inconvenient and the simple technique to be described may offer some advantages. The temperature of the water fed to the Cyclosizer is maintained at a constant value for added reproducibility.PROCEDUREThe present overall treatment of the subsieve material (minus 37 \lm) fed to the Cyclosizer incorporated several refinements compared with normal operation and these may be best illustrated by anactual example. Material to be cyclosized (25 to 100 g depending on size distributIOn and specific gravity) is completely dispersed in water at 23 QC by vigorous stirrmg, using suitable dispersants if necessary, in a...

Jan 1, 1974

By Paine G

Kidston Gold Mines commenced mining in 1984 and currently mine approximately 10 million tonnes per annum of ore and waste using a conventional truck and shovel open pit method. The overall mine grade is a low 1.82 grams per tonne.The mineralisation is generally uniform within the ore zones and mining boundaries are staked out from blasthole assays according to pre-determined cut-off grades. Buffer blasting is necessary to minimise post-blast lateral movement of in-situ grade for digging control.The characteristics of the rock currently mined vary widely from soft oxidised to hard unweathered rocks. Blasting problems have been experienced during the initial mining phase in these harder rocks.

Jan 1, 1986

The application of new and currently practised mining techniques in new areas and at greater depths necessitates considerable and immediate research effort. This effort is aimed at identifying the factors which make a particular method suitable and economically viable in a given geological, structural and operational environment. These factors, together with greatly enhanced knowledge of a deposit at the exploration and planning stage, allow selection of the most appropriate and efficient mining method in a new area such that coal resource recovery is maximised in a cost effective manner. Current research and future requirements for research into mining methods and associated equipment and mine services are reviewed.

Jan 1, 1981

By Swift J. D

A key parameter affecting the performance of gravity thickeners in hydrometallurgical processing operations is the aggregation state of the feed after the addition of a flocculant. New procedures which measure the settling ratelsize relationship and the size distribution of aggregates in their process liquors have been used to quantify the aggregation state of the feedwell, overflow and underflow streams in a tailings thickener. The data obtained have been related to the thickener's operation and to a change in the flocculant dosage. A comparison is also made between the settling rate/size relationships determined with these new procedures and the mud-line settling rates from cylinder tests.

Jan 1, 1991

The application of new and currently practised mining techniques in new areas and at greater depths necessitates considerable and immediate research effort. This effort is aimed at identifying the factors which make a particular method suitable and economically viable in a given geological, structural and operational environment. These factors, together with greatly enhanced knowledge of a deposit at the exploration and planning stage, allow selection of the most appropriate and efficient mining method in a new area such that coal resource recovery is maximised in a cost effective manner. Current research and future requirements for research into mining methods and associated equipment and mine services are reviewed.

Jan 1, 1981

Accounting for borehole damage in analytical modelling of explosively generated stress waves is important for predicting the finer details of the stress wave patterns observed in the field. The classical Sharpe's [19421 concept of an effective borehole larger than the initial borehole diameter has been widely accepted to explain material damage around a borehole. A new analytical model based on dynamic compaction is advanced to predict far-field stress wave patterns. This model supports field data corresponding to reduced frequency of oscillations and increased damping. The present model recovers the earlier result when compaction around the borehole representing borehole damage is ignored.

Jan 1, 1990

By I Mason, M van de Werken, B Zhou, J Hargreaves, W Stasinowsky

A critical step in open cut coal mining is clean removal of the overburden. This is usually achieved by drilling, blasting and digging. A key part of this process being successful is to stop drilling at the correct blast ‘stand-off distance’. The stand-off distance is the distance between the base of the drilled blasthole and the top of the coal horizon to be mined. Having this correct provides a protective cap of rock above the coal horizon so that the blast will fracture all the overburden without damaging the coal horizon or mixing it with the overburden. Drilling beyond the correct stand-off distance causes the blast to continue into the coal horizon, damaging it and mixing it with the overburden, leading to significant losses of coal product. Conversely, drilling short of the correct stand-off distance results in additional work to remove the intact overburden.

Sep 1, 2024

By N Patel, S Narendranathan, T Mok, J Lowe

The Hazelwood Mine (HM) commenced operations in the 1950s and was originally operated by the State Electricity Commission of Victoria (SECV) prior to it becoming privatised. ENGIE, the current owners of the Hazelwood Mine ceased operations in 2017 and have since transitioned the site into the rehabilitation and closure phase, which is to encompass a full pit lake as part of the final landform. A key aspect of HM closure is the maintenance of long-term stability of the pit slopes to deliver a final landform which is safe and sustainable, particularly given its proximity to critical public receptors. The Princes Freeway, which is the primary access route to the Latrobe Valley (LV), and the Morwell Township are both located immediately to the north of the HM. With due consideration of the mine void and nearby public receptors, the authors performed slope stability assessments of critical mine

Aug 2, 2023

By Giannini L, Kelsey P

A fundamental problem in mine planning is the determination of the production schedules over the life of the mine. The objective is to maximise profit in terms of the net present value without transgressing the physical constraints of the mine

Jan 1, 1998

By Mur D. M

Metal ferrites are formed by the high temperature reaction of various metal oxides with hematite and are commonly found in the calcines derived from the sulfation roasting of zinc, copper and nickel sulfide concentrates. The Jarosite Process is designed to treat such zinc ferrites by hot acid dissolution but little information is available on the basic reactivity of various ferrites and the effect of Eh. As part of an overall study of the reactivity of calcine products from copper and nickel sulfide concentrates it has been found that Eh plays an important role in the rate of dissolution of magnetite, hematite and nickel oxide by HC1 and H2SO4. Further studies on the reactivity of pure synthetic copper,zinc,and nickel ferrites also show a dependence on Eh. This paper discusses the relative reactivity of iron oxides and metal ferrites in 1 M HC1 and the results of electrochemical studies using cyclic voltammetry. A mechanism for the dissolution reaction is proposed as well as factors which determine their leaching. It is shown that the rate of leaching of metal ferrites with HC1 is enhanced in the presence of reducing agents such as Cu(I) and Sn(II). By contrast the leaching of NiO is enhanced by oxidising agents such as Cu(II).

Jan 1, 1987

By N Javati, G D. Carman, D Kikiha, B Likia, K Dala, J McPhie, R Johnstone, D R. Cooke, J L. Blackwell

The 40 Moz Ladolam gold deposit on Lihir Island, Papua New Guinea is the worldÆs largest, low-sulfidation, epithermal gold deposit, in terms of contained gold. The deposit has average grades of 2.42 g/t Au (LGL Resources Reserves Update, 2008) and gold is hosted primarily in refractory pyrite. Lihir Island is part of the 150 km long, Tabar-Lihir-Tanga-Feni, alkalic, volcanic island chain located in the New Ireland basin. Five volcanic blocks comprise Lihir; Plio-Pliestocene Huniho, Kinami and Luise volcanic edifices are built on top of remnant Pleistocene Wurtol Wedge and Londolovit Block (Wallace et al, 1983). The Ladolam gold deposit is located in the central portion of the dissected Luise volcanic edifice and is composed of four main orebodies: 1. Minifie, 2. Lienetz, 3. Coastal, and 4. Kapit. An active geothermal system is overprinted on the ore deposit, localised along north-trending lineaments, and is expressed as hot mud pools and fumaroles. The focus of open pit mapping and drill core logging, as part of ongoing PhD research, has been in the Minifie and Lienetz orebodies. The deposit geology is grouped into four main phases: 1. volcano-sedimentary host rocks, 2. porphyry-style biotite alteration and related hydrothermal breccias and veins, 3. epithermal-style breccias and veins, and 4. modern geothermal alteration. Gold is associated with epithermal-style alteration and mineralisation. Ongoing observations of the Minifie and Lienetz orebodies are highlighting differences in the geology and paragenetic histories. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Nidagal V

This paper discusses the dewatering strategy adopted and the considerations and procedures required to incorporate a dewaterinq scheme into the Mt Whaleback mining operation. It concludes that in pit pre-dewaterinq has successfully allowed mining to progress below the standing water level with the minimum of disruption or radical change to the mining method. It is recognised however, that dewatering is not a static activity and there is a requirement for ongoing investigations and development. Pre-dewatering commenced in October, 1984. Purpose designed pumping trailers have been employed to minimise the loss of pump availability resulting from the frequent. need to remove and reinstall pumps when close vicinity blasts occur. To July, 1986, some 0.5 Mm' of groundwater had been pumped from the unconfined orebody aquifer. Mining has progressed to some 20 m below the standing water level without. any undue water associated problems. Ultimately, it is ,cheduled to extend some 300 in below the original water level in the West Pit. With the development of an increasing area of the mine below the standing water level, the influence of seasonal high intensity rainfall events, which had previously caused little concern, now need to be addressed. Pumping equipment has been designed to evacuate storm water at a rate consistent with mine production Considerations.

Jan 1, 1986

The necessity for good management and economic working in our mines and ore-dressing sheds is impressed upon us by the present low prices of all our metals. Silver, lead, copper, and tin have all suffered a heavy decline during the last six or twelve months, and many mines have been shut down simply on account of the low market value of the ore produced. After fully considering the position of the mining industry. I am convinced that considerable improvements will have to be made to make it as prosperous as it ought to be. The most obvious of these improvements are good management, good machinery, and as little interference by directors as possible. If these conditions are insisted upon and carried out efficielltly a poor mine may have a chance to weather the storm.There is no doubt that the present depression is the refilult of over-speculation and general loss of confidence by which the whole commercial system has been affected, and every branch has suffered more or less, mining not excepted. It has suffered heavy losses in the past, and the future is not over bright we are, therefore, compelled to be careful in everything by which mining is affected and savings can be secured.

By B Prasad, M P. Roy, P K. Singh, C Drebenstedt

Blasting operations play a pivotal role in the overall economics of opencast mines. The blasting subsystem affects all the other associated subsystems, ie loading, transport, crushing and milling operations. Fragmentation control through effective blast design and its effect on productivity is a challenging job for the practicing blasting engineer due to inadequate knowledge of actual explosive energy released in the borehole, effect of varying initiation practice in blast design and its effect on explosive energy release characteristic. This paper describes the result of a systematic study on the impact of blast design parameters on rock fragmentation at two mines in India. Both the mines use draglines and shovel-dumper combination for removal of overburden. Despite its pivotal role in controlling the overall economics of a mining operation, the expected blasting performance is often judged almost exclusively on the basis of poorly defined parameters such as powder factor and is often qualitative, which results in a very subjective assessment of blasting performance. Such an approach is a very poor substitute for accurate assessment of explosive and blasting performance. Forty-seven blasts were conducted with varying blast designs and charging patterns and their impact on the rock fragmentation are documented. A high-speed camera was deployed to record the detonation sequences of the blasts. The efficiency of the loading machines was also correlated with the mean fragment size obtained from the fragmentation analyses.CITATION:Singh, P K, Roy, M P, Drebenstedt, C and Prasad, B, 2015. Blast design parameters and their impact on rock fragmentation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 755–762 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By M Paakkunainen

Sampling is often the most critical part in process analysis. When the mean of a continuous lot, such as a process stream within a given time interval, is estimated by calculating the mean of several samples, the uncertainty of the estimated mean depends usually on the sampling strategy. Three different strategies can be used: systematic, stratified or random sample selection. The standard deviation of the lot mean is different for these methods so that systematic sampling usually gives the smallest and random sampling the largest standard deviation. Pierre Gy developed a method where the sampling errors of one-dimensional lots for these three strategies can be estimated from a variogram, which is calculated from a variographic experiment, ie from a set of one-dimensional time series measurements with fixed sampling interval. While variogram is an excellent tool for characterising and displaying the variability of autocorrelated processes as function of time, the sampling error estimation from it is quite laborious, however. In this work an alternative method for estimating the sampling errors was developed. The process is divided into strata of equal sizes, varying the length of strata similarly to variographic analysis. For stratified sampling the standard deviation estimates are obtained by analysis of variance and for systematic sampling by fitting a linear regression line to each stratum and calculating the residual variances. By pooling the individual variance estimates the variance estimates that are corrected for autocorrelation are obtained. The new method was tested with simulated and real data sets having periodic, random and/or drift fluctuations. For stationary processes the results agreed well with the results of the GyÆs variographic method. The method can probably be generalised to estimate the sampling variance of higher-dimensional lots.

Jan 1, 2005

The New Southern Railway (NSR) involves the excavation of approximately 10 km of single bore tunnel from Tempe Reserve, Tempe, to Prince Alfred Park (PAP). PAP is located just south of Central Railway Station in SydneyÆs Central Business District (CBD). From Tempe Reserve the alignment takes the tunnel under Sydney Airport including the main north/south runway. Sydney Airport is approximately 8 km south of the CBD. The NSR is being constructed by a private group, the Transfield Bouygues Joint Venture (TBJV). Transfield is a major Australian contractor and the French contractor, Bouygues, is providing the soft ground tunnel construction expertise and is also responsible for the design of the concrete segmental lining. This paper sets out to present in some detail the issues involved in tunnelling under the airport and in particular under the north apron, the main north/south runway and the new elevated roadway. The paper concentrates on these three areas on the airport with an emphasis on the following. The risks involved and measures taken to minimise the risks in tunnelling under the International Terminal north apron (with Jumbo Jets parked immediately above). Secondly, settlement predictions, settlement and runway operation criteria and the actual settlements that have occurred on the main north/south runway. Finally, the criteria that was developed during the construction of the deep bored piers for the elevated roadway at the Domestic Terminal as the TBM passed through this area of construction activity.

Jan 1, 1999

By G Harbort, D Zoetbrood

"The Phu Kham copper-gold operation in the Laos People’s Democratic Republic (PDR) is owned and operated by Phu Bia Mining Limited. PanAust Limited holds a 90 per cent interest in Phu Bia Mining Limited, with the remaining ten per cent held by the Laos PDR Government.The original 12 Mt/a copper-gold concentrator at Phu Kham commenced production in April 2008. An incremental improvement program resulted in a number of circuit changes being incorporated by 2011, including conversion of conditioning tanks to flotation cells and the installation of a Jameson Cell cleaner scalper. In 2012 the Phu Kham Upgrade Project was commissioned to increase throughput to 18 Mt/a. In April, 2013 the Phu Kham Increased Recovery Project was commissioned to maximise performance by debottlenecking the plant IsaMill™ regrind and cleaning capacity.With the variable mineralogy of Phu Kham ore, control of the c concentrate regrind circuit is essential in terms of achieving effective liberation to maintain concentrator performance. On a routine basis laboratory regrind signature plot data is compared with daily surveys of the operational IsaMills™. More extensive surveys are also conducted to determine size distribution on a mineralogical basis and the effect of fine regrinding on pulp electrochemistry and flotation performance. This paper provides a review of the operating performance of the Phu Kham IsaMills™ with regard to power draw, feed and product size distribution, feed per cent solids, mineralogy and pulp electrochemistry. Operating performance is compared with the IsaMill™ signature plot test for predicting performance.Citation:Harbort, G, Zoetbrood, D and McNab, B, 2016. Operating Performance of the Phu Kham IsaMill™, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 39–50 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By D J. Williams

The approach to the disposal and storage of mine tailings is slowly evolving. Tailings disposal has been based on minimising short-term capital and operating costs, with rehabilitation costs discounted by the application of a high discount factor in a net present value approach to accounting. This has led to the widespread adoption of surface tailings storage facilities (TSFs) to store slurried tailings delivered by robust and cheap centrifugal pumps and pipelines. Depending on the site climate, rate of rise of the tailings, nature of the tailings and the extent to which supernatant water is removed from the surface TSF, the tailings may or may not dewater, densify and gain strength. High rates of rise of dilute tailings to a facility used to store both tailings and supernatant water results in a wet, low-density, soft tailings deposit that not only occupies a large storage volume but also presents rehabilitation difficulties. A low tailings density results in high containment wall costs, very high rehabilitation costs and a low potential for future land use or ecological function. Overall, the cost of slurried tailings disposal, thought to be low, is actually high. However, low rates of rise, even of dilute tailings, in a dry climate with efficient supernatant water removal can produce a dewatered, high-density, stiff tailings deposit that may occupy a large footprint but to shallow depth that is relatively easy to rehabilitate. There are advantages in dewatering tailings in the processing plant to recover process water and chemicals, facilitate tailings disposal in a more solid form and facilitate rehabilitation. However, the cost of dewatering in-plant can be high, and the process water may not lend itself to reuse. There are also advantages in removing supernatant water to facilitate solar and wind drying of exposed tailings, although water is lost to evaporation and the dried tailings may best be harvested prior to inundation by fresh tailings or rainfall run-off. This paper discusses the background and trends towards the elimination of conventional surface slurried TSFs, with examples presented of the management of black coal and other tailings, including those that are clay mineral-rich.CITATION:Williams, D J, 2015. Towards the elimination of conventional surface slurried tailings storage facilities, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 11–24 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

During the last 12 years the dominant theme at Mount Isa has been production expansion. Production rate of 3,200 tons per mine day in 1953 increased to 11,000 tons per mine day in 1960, completing the first stage of the programme. The second stage is still in progress. It is planned to increase production of lead and copper ores to 19,500 tons per mine day in 1968.Current mine workings comprise an area 2 miles long and 1/2 mile wide, the deepest production level being 2,000 ft below surface. During the next 10 years it is anticipated that mining will be carried out to a depthof 3,200 ft below the surface. The rapid extension of the mine has necessitated frequent re-appraisals and modifications to the primary ventilation system, and a system with considerable in-built flexibility has gradually evolved. Since 1953, volume circulation has increased eight-fold to approximately 2,400,000 c.f.m.To suit various mine operating requirements, a combined pressure-exhaust system of ventilation was adopted.The usefulness of this system is at a maximum when the fans installed permit ready changes in the location of the boundary between adjacent spheres of fan influence.Air flow through openings to the surface can be controlled or used as required. This feature is considered necessary for a mine where underground workings are comparatively shallow and caving to the surface willoccur.A major heat problem exists due to climate conditions, high geothermic gradient (one degree Fahrenheit in 95 ft), and oxidation in leached and brecciated areas.Because of this, quantities of air far in excess of the minimum requirements for dust removal are required to ensure satisfactory environmental conditions. In assessing fan pressure, consideration was given to 1. the mine resistance, and the requirement for pressure differential capability,2. the pressure requirement for deeper mining, with due allowance for booster fan use where appropriate,and3. the desire to avoid fan operation at pressure duties above the region of peak fan efficiency.The latter feature provides a safety margin between maximum operating pressure and the stall point of the fan.

Jan 1, 1967