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By H Indirawati, R Ayres, A Nur Kasnanto, S Konopa

As a project moves through the mine life cycle, the quantity of data available increases and the understanding of the orebody matures. Incorporating new information quickly and efficiently in current 3D models, is essential for adding value across the life-of-mine value chain. At the Martabe Gold Mine, the resource development group manages 14 drill rigs on six resource projects, including three operating mines. The Martabe deposits are geologically complex and the volume of new information that becomes available each day is substantial. It is imperative that new geological and assay information is integrated into the 3D models as soon as possible, so that drill planning and targeting can be modified accordingly. Martabe uses Leapfrog<sup>®</sup> 3D software to update and interrogate the 3D models on a dynamic basis as data becomes available. This results in faster and more effective changes to drill planning and schedules. The impact of this is better drill productivity and cost savings due to optimal drill targeting, and availability of up-to-date models incorporating the most current data. CITATION: Konopa, S, Ayres, R, Nur Kasnanto, A and Indirawati, H, 2018. Optimised drill targeting using dynamic 3D modelling, Martabe Gold Mine, Indonesia, in Proceedings Complex Orebodies Conference 2018, pp 99–101 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By M Angus, S Konopa, A Virisheff, S Crispin

A positive mill reconciliation at a mine is a double-edged-sword. Much back slapping happens. The bank and the board can’t get enough until the downside becomes apparent. Over a prolonged period, there becomes an issue with market perception and the potential for shareholders to be misinformed regarding the potential value of the project. In addition, there are impacts on mine scheduling, waste allocation (or lack thereof), government expectations, and the potential for misguided external assumptions regarding the ‘unexpected’ results. The PT Agincourt Resources Martabe Gold Mine has shown a significant under-call, in the order of 20% total gold metal, between the Mineral Resource (MR) estimates and Grade Control (GC) estimates since production commenced in 2012. Recently, the under-call has been reduced by incorporating the use of grade control drilling in the MR grade estimates. Despite recent improvements in reconciliation, drilling in 2017 at both Purnama and Barani open pits shows that infill reverse circulation (RC) drill holes often produce significantly higher grades than those predicted in the MR block model. CITATION: Angus, M, Virisheff, A, Konopa, S and Crispin, S, 2018. Martabe Gold Mine, Indonesia: a positive solution for positive reconciliation, in Proceedings Complex Orebodies Conference 2018, pp 76–78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By J Pearce, B Miles, V de San Miguel

Incorporating industry best practice waste rock management methods can be a relatively straight forward task when preparing management documentation, such as an acid and metalliferous drainage management plan (AMDMP). However, a key difficulty is the incorporation of industry best practice methods that are practical and non-compromising on their purpose from a scientific standpoint. The second key difficulty is the implementation of these practical methods as various operational groups/departments are typically relied upon to execute and take ownership of different tasks or procedures.One approach to overcoming these difficulties is to develop an AMD Operations Manual (AMDOM) that:•Incorporates, where practicable and without compromising scientific merit, existing processes that those groups/departments ultimately responsible for the execution of the management action are familiar with; and•Provides standalone, simplistic, and easy to follow procedures for site personnel. The purpose of the standalone operations manual is to ensure site personnel who are responsible for undertaking specific procedures, have clear, step-by-step instructions for an individual procedure, without requiring interpretation and understanding of the more comprehensive AMDMP.In adopting a best practice approach to waste rock management for their iron ore mine in Western Australia’s Pilbara region, Roy Hill developed an AMD Management System that is comprised of both an AMDMP and an AMDOM that are connected through adaptive management processes. The Roy Hill iron ore mine, which has a mine life of 18 years, will require the management of more than three billion tonnes of waste rock.CITATION:de San Miguel, V, Miles, B and Pearce, J, 2018. Practical waste rock management at the Roy Hill iron ore mine, Western Australia, in Proceedings Life-of-Mine 2018, pp 80–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

It is a great pleasure to accept the invitation to open this Joint Conference of The Australasian Institute of Mining and Metallurgy and the American Institute of Mining, Metallurgical and Petroleum Engineers. It is the second invita- tion to participate in the Conference that I have accepted. When it was being planned, the President wrote to me to invite me to be one of the speakers in one of the technical sessions. I wrote accepting the invitation, and when my present appointment was announced, there was a nice question about the earlier commitment. The upshot of it all is revealed by the present arrange-., ment: you get me as opener and the more sub- k stantial speech is to be given by Professor Rupert Myers, my friend and former colleague who will not only be able to contribute from the standpoint of an experienced University admini- strator, but will also speak from a professional training and experience much more closely relat- ed to the concerns of this Conference than I possess. Though it is a joint meeting and the speakers will include distinguished figures from North America, I hope that since the venue is Australia, I may be permitted to speak with an Australian emphasis. I have recently had a brief glimpse of part of the Australian mining industry. In the course of a journey through the Northern Terri- tory we-my wife and I-visited Gove, Groote Eylandt, and Tennant Creek. At Gove we saw the remarkable Nabalco development in bauxite and alumina and the very impressive town plan- ning development at Nhulunby, the major man- ganese enterprise at Groote Eylandt, and the gold mining activity at Tennant Creek. For lay people like us, a gold pour was arranged at Tennant Creek and that was a spectacular sight. On earlier occasions, and before my present appoint- ment, I had visited Mount Isa and the Utah fields, and Queensland Alumina at Gladstone. I have not seen the cradle of the modern mining industry, using cradle perhaps loosely, at Broken Hill, nor have I seen the great Pilbara develop- ment, nor Weipa. This is not for want of generous invitations and it is my hope that within the not too far distant future this will be rectified. Then there is the Australian petroleum industry and the great industries which make their products from the minerals mined which I have yet to See.

Jan 1, 1978

By H Mansouri, M A. Ebrahimi Farsangi, F Faramarzi

A blast fragmentation model is developed based on the gamma function to describe the run-of-mine fragmentation distribution. The model presented is aimed to benefit from simplicity in application and also to be efficient in description of the fine to coarse part of the blast rock fragments. In fact, the gamma based model (KC-KUM), gives a unit distribution curve, which is made up of two separate equations, covering different fragment sizes in the muck pile. The generated values of the fines to central part of the equation and the central to coarse part of the equation are connected at the 40 per cent grafting point. For validation, eight production blasts, which were specially designed for this purpose, were carried out at an iron ore mine (Jalal-Abad iron ore mine/Iran). Results achieved by KC-KUM and two of the most well-known models. Kuz-Ram and Swebrec, are compared with measured data. Moreover, to assess the models’ efficiency in presenting the best distribution curve, a Logarithmic error method is chosen. Based on the achievements. KC-KUM has the least deviations by the least absolute log error of 0.52, whereas the values obtained for the Swebrec and Kuz-Ram models were 0.79 and 1.34 respectively. Furthermore, the models were applied to predict X80 for 12 production blasts carried out at Gol-e-Gohar iron ore mine/Iran. These predictions were compared with the results from these trials. The coefficient of determination (R2) and root mean square error (RMSE) are calculated. Consequently, the highest R2 was obtained for KC-KUM at 0.837 with the least RMSE of 11.31. On the other hand, R2 and RMSE are equal to 0.832 and 20.19 for Swebrec; and 0.813 and 19.75 for Kuz-Ram respectively. The results obtained suggest the superiority of the KC-KUM model over the other two models in assessment and prediction of blast fragmentation in a reliable way.CITATION:Faramarzi, F, Ebrahimi Farsangi, M A and Mansouri, H, 2015. Prediction of rock fragmentation using a gamma-based blast fragmentation distribution model, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 685–692 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By C Pope, M Tannock

Mining exploration and development projects in Australia are being negatively affected by the highly complex regulatory and bureaucratic processes at all levels of government. These processes affect mining companies operating in Australia by impacting on timelines and the cost of developing a mining project. It is not uncommon for the granting of project approvals to take in excess of five years, meaning that mining companies struggle with productivity, efficiency, time frame and cost issues in respect to their projects in Australia. As the mining boom in Australia is moving from the investment to the production phase, it is now more important than ever to maintain a regulatory landscape that facilitates rather than discourages new investment.While one of our key arguments is that there is too much burdensome regulation and red tape in Australia, we are also strongly believe that regulatory intervention is necessary to ensure that appropriate checks and balances are in place to serve the public interest and manage environmental, health and safety, social and other development-related impacts that may arise from a mining project. However, the regulatory intervention in Australia has come to a point where it is excessive and starting to discourage valuable investment in mining projects for nominal return to the public. Excessive regulation or ‘red tape’ impedes productivity and competitiveness, deters investment and innovation and costs jobs, all of which ultimately impact on the growth of Australia and the standard of living of all Australians.This paper aims to examine and compare the federal, state and local regulations that govern mining projects in Australia. It will highlight how these regulations are unnecessarily complex, lengthy and duplicated and how they can be streamlined to reduce red tape. In doing so, the paper will evaluate the recommendations proposed by the Productivity Commission Report on Major Project Assessments released in 2013, which include the recommendation to move to a ‘one project, one assessment, one decision’ regulatory model.CITATION:Pope, C and Tannock, M, 2015. Project development and regulation red tape – a comparative analysis: does it need to be so complex?, in Proceedings Iron Ore 2015, pp 621–630 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By M J. Davies, R S. Davies

Despite increased expenditure, the global discovery rate of world-class ore deposits has been in decline for over a decade (Schodde, 2017). Mineral exploration has traditionally followed an empirical approach, searching for evidence of mineralisation upon the surface of the planet, then drilling to define the extent of an ore body beneath the surface. As outcropping deposits in well-defined areas are depleted, there is a need for exploration to extend to less well-explored search spaces. One popular new frontier is exploration at greater depths beneath the Earth's surface. However, exploring for deep deposits with limited surficial evidence requires the implementation of predictive targeting methodologies (Hronsky, 2011; McCuaig & Hronsky, 2014). The Mineral Systems Concept (Hronsky & Groves, 2008; McCuaig et al., 2010) provides a framework for predictive exploration targeting. Ore deposit formation is recognised to be a focused mineralising event. These events represent self-organising critical systems and are underpinned by the interaction of complex, non-linear processes. Through the collection and analysis of datasets that map mineralising processes, it may be possible to predict the size and location of resultant ore bodies. CITATION: Davies, M J and Davies, R S, 2018. Beyond below-ground geological complexity: Developing adaptive expertise in exploration decision-making, in Proceedings Complex Orebodies Conference 2018, pp 95–98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By I Onederra

A better understanding of the detonation performance of an explosive charge can be gained by directly measuring pressure, temperature and velocity of detonation (VOD). This is particularly important with explosives used in the mining industry because their performance is directly influenced by the degree of confinement given by the borehole diameter and the surrounding rock mass. A project funded by the Australian Coal Association Research Program (ACARP) was initiated in early 2009 with the view to design and build cost-effective prototype instrumentation to measure the relative differences in detonation pressures and temperatures of commercial mining explosives. The project’s primary focus was on low-density explosives. Low-density (also referred to as low shock) explosives have been available in various forms for nearly 20 years. There have been significant advances in the availability, reliability and flexibility of these explosives, which now offer a range of densities and degrees of water resistance. Their detonation performance is not well understood and cannot be accurately predicted with current ideal and non-ideal detonation codes. It was therefore viewed as important to be able to directly measure pressure and temperature during the detonation process of these complex mixtures in production blastholes. Identifying the pressure release patterns of both conventional and low-density explosives under different geotechnical conditions should provide the necessary information to both validate detonation codes and better define input parameters for breakage and fragmentation models. This paper gives a general description of the prototype instrumentation developed and reports on the results obtained to date in full-scale conditions.

Nov 8, 2011

By J Watson, C Zhang, I Canbulat, C Wei

Coal burst is defined as a dynamic release of energy within the rock or coal mass in underground coalmines that causes violent rock or coal ejection in the vicinity of mine excavations. It poses one of the highest safety and productivity risks in the mining industry as coal bursts have the potential to cause multiple fatalities. As Australian coalmines go deeper, the likelihood of coal burst increases. Thus, it is critical to assess the ground support requirements in coal burst-prone conditions. A previous study conducted by the authors (Wei et al, 2022) reviewed the support capacities of a wide range of ground support elements in laboratory tests. This study aims to examine the role and effects of the ground support elements and systems for Australian underground coalmines to minimise the damage caused by catastrophic dynamic failures (ie coal and rock burst) and enhance the safety of mine workers.

Nov 29, 2022

By I Y. Maslov, S A. Gorinov

It was demonstrated that the stable propagation of the explosive process is possible in low-density emulsion explosives (EEs) obtained through mixing of emulsion with a significant amount of expanded polystyrene (or other similar) granules. Such a process takes place in the form of a detonation-like wave of emulsion drops in explosive gas streams flowing out of the high-pressure area of the reaction zone.Chemical reaction in such EEs takes place in the form of surface combustion of emulsion particles interacting with the gas stream.A method was developed for determining parameters of decomposition of low-density EEs, and it was demonstrated that a gradual pressure increase takes place in products during the explosion of such EEs.The performed analytical research allowed low-density EEs (obtained through mixing of emulsion with a significant amount of expanded polystyrene) to be recommended for smooth blasting.Industrial-experimental blasts at quarries of Ural and Siberia, with extreme positioning of sides and using low-density EEs, have confirmed the viability of the recommendations given.The obtained results are useful in the advancement of smooth blasting technology using low-density EEs.CITATION:Gorinov, S A and Maslov, I Y, 2015. Physical and technical evaluation of possibility using low-density explosives in smooth blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 555–564 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By S Munn

Today, it can be said that the majority of mines utilise communications equipment in one form or another. Either for communications between staff making their day-to-day operations more efficient, or for emergency communications, as well as linking computer based mine management systems, and providing remote control over complex mobile and fixed machinery. With the advances in technology now available, we are moving into the next generation of mine communications equipment, using digital communications in the underground mine environment. It is a proven fact that an efficient underground mine communications system can help maximise production, by providing major gains in areas such as equipment and manpower utilisation, staff and vehicle tracking, reaction times to break downs and emergencies. In this paper we will describe some of the facilities that are currently available, as well as what will soon be available to mining and tunnelling companies around the world.

Jan 1, 1999

By T Takayama, R Muroi, M Matsumura

The steel industry occupies 14 per cent of CO2 emissions in Japan, and the sintering process is one of the major emitters. Since most of CO2 released from the sintering process comes from coke fine combustion, replacement of coke fines with biomass char as bonding agent is a potential countermeasure. In order to explore the effective use of biomass char, we chose char made from Palm Kernel Shell (PKS) as a sample. First, the char’s combustion behaviour was examined with varying the char’s particle size by means of admixing the char in alumina ball packed bed placed in an electric furnace. As a result, the finer the PKS char the faster the burning rate and reaching a higher temperature compared to coke fine. In addition, it is also concluded that the optimum size of PKS char was larger than coke fines. Next, the effect of different heat profiles on sinter structure was examined by sintering tablet made of chemical reagents. In this experiment, the chemical composition is designed based on sinter composition. By this sintering test, even at high temperature, rapid cooling is effective to make fine sinter matrix and fine pores, which has possibility for high sinter reducibility. Based on these two experiments, using PKS char as a sinter fine source has the possibility to improve sinter reducibility.

Nov 8, 2021

By M Zoorabadi

Overcoring is a common technique to measure in situ rock stress using the concept of stress relief. The strains measured during overcoring are used to calculate the stress tensor assuming continuous, homogeneous, isotropic and linear elastic behaviour. This approach does not recognise any effect of the thickness of the rock annulus produced during overcoring instead assuming that the stresses are entirely a function of the difference in strain between the start of the overcoring and the end with no regard to the transient strains produced. Three-dimensional numerical modelling was used to simulate the overcoring process and investigate the impact of core diameter on the transient stresses and strains during overcoring. This study showed that in thicker core, maximum transient axial stresses and strains occur when the drill bit approaches the measuring point and greater tensile axial stresses were produced when the annulus was thinner. CITATION:Zoorabadi, M, 2018. Numerical study of annulus thickness on overcoring stress measurements, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 274–278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By S Khosrowshahi, A Weeks, W J. Shaw

"To provide an indication of expected performance of the mine and mill, feasibility studies should include an assessment of the expected day-to-day variability in process plant feed. Attempts to do this based on conventional resource models will be flawed as such studies fail to consider and account for the in-built smoothing (averaging) of input data.This can lead to one of two situations: an expensive, over-engineered process plant that can cope with every possible situation, or operational strategies that fail to manage the natural variability within the orebody and the impact of day-to-day operational decision-making.In both cases the value of the project diminishes through excessive capital costs or reduced throughput or recovery during operations.Unlike conventional estimation techniques, the geostatistical method of conditional simulation can reproduce the inherent variability of the deposit. Once a valid model has been developed, it is possible to analyse the model using a transfer function that simulates the proposed mining processes and provides a representation of the likely variation of mill feed characteristics at any time scale.The case study demonstrates how the proposed mining strategy would result in mill feed being considerably more variable than expected, resulting in poor recovery, low throughput and potential breaches of environmental conditions. Mitigation measures included budgeting for additional mining equipment to enable greater flexibility during mining and revised stockpiling and crusher feed strategies.Awareness of the benefits of modelling the variability of geometallurgical parameters will increase the use of this approach in producing more realistic financial models of expected mine performance at the design stage.CITATION:Shaw, W J, Khosrowshahi, S and Weeks, A, 2013. Modelling geometallurgical variability - a case study in managing risk, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 247-252 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By B McCarthy

Mining has been typified of late as a boom and bust, cyclical industry operating against a steady decline in the size and quality of mineral deposits. Decreasing deposit grades and increasing costs of traditional mining techniques, all in the face of another commodity downturn, are forcing mining companies more than ever before to seek out new and innovative ways to operate. New technologies are emerging to model, control and track resources through the mining value chain, to move material about mines more efficiently, and to identify and separate ore from gangue early in the extraction process.Discovering such technologies however is only the first challenge for mining companies. Actually implementing technological change successfully has proved to be an even bigger challenge. Like for many industries, fulfilling the promised benefits for the expense and timing envisioned, has not been easy when innovative technologies are introduced.Citing the author’s insights and experiences in a number of emerging technologies, this paper explores barriers to implementing technological change in the mining context. Key elements of a change management framework, first developed for implementing mine management systems, are described to give mining executives insight into how they and their organisations can succeed through technology-driven change.CITATION:McCarthy, B, 2016. Successfully implementing technology-driven change in the mining environment, in Proceedings International Mine Management Conference, pp 89-104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By F Ramos

Conventional techniques for resource estimation generally involve the laborious analysis of variograms and the specification of parameters for covariance functions. In large deposits, construction of resource models and their update require significant amount of manual work, expert knowledge and time. In this paper we take a machine learning view to the problem of resource estimation. This is a non-parametric Bayesian method, leading to automatic parameter estimation (learning). Through Bayesian learning, the parameters of the model can be obtained by optimising a quantity known as the marginal likelihood. The main advantage of this approach over conventional maximum likelihood estimators is that the objective function incorporates the OccamÆs razor principle. This allows the comparison of different statistical models û for example, models designed with different covariance functions û and naturally penalises complexity, thus avoiding overfitting. Our technique presents significant flexibility for the definition of mean and covariance functions and permits the usage of more sophisticated models.The second contribution of this work is the formulation of a data fusion mechanism that continuously updates the resource model. As mining progresses, more information becomes available. For example, the hardness of the rocks can be measured while drilling blast holes, grades of ore and contaminants are obtained from cone logging. This information is in general available at a finer spatial resolution but can be more uncertain. The data fusion mechanism can seamlessly estimate the uncertainties of the different types of information and fuse them as new measurements are acquired. This procedure can significantly improve the quality of the resource model, defining new grounds for stochastic mine planning. We demonstrate the effectiveness of our approach in estimating iron ore deposits by integrating information about different grades.

Sep 26, 2011

By A Boucher, M Baudin, P Androszczuk, I Minniakhmetov, A Rigby, P Machado, M Wright, B Van Dijken

IGO Ltd’s (IGO’s) Nova Operation (Nova), which is 160 km east-north-east of the town of Norseman in Western Australia (WA), mines and processes nickel-copper-cobalt (Ni-Cu-Co) sulfide ore from the magmatic Nova-Bollinger Deposit (Nova-Bollinger), which is hosted by the Mesoproterozoic age high-grade metamorphic rocks of the Albany Fraser Orogen. Over its 56-month life-of-mine (LOM) operations to 31 December 2020, Nova has processed 5.63 Mt of ore grading 2.04 per cent Ni, 0.86 per cent Cu and 0.07 per cent Co from its underground mine. At the end of 2020, both the Nova-Bollinger JORC Code reportable Mineral Resource estimate (MRE) and Ore Reserve estimate (ORE) were >90 per cent classified in the highest JORC Code confidence categories of Measured Mineral Resource and Proved Ore Reserve respectively. The high JORC Code classification confidences assigned to the Nova-Bollinger MRE and ORE results from the 386 km of surface and underground diamond drill testing of the deposit to a nominal 12.5 by 12.5 m pierce point spacing in mineralisation. The close spaced high-quality drilling and bulk mining method employed at Nova has effectively removed the need for any grade control modelling outside of the MRE process. Importantly, having only the one fully drilled out deposit being mined and only the one process plant, Nova’s reconciliation process is in the fortunate situation of not being confounded by issues such as external ore sources and constant updates as new grade control information becomes available. IGO’s Nova reconciliation processes are focused on reconciliation ratios that quantify operational period differences between the MRE and ORE head grade and tonnage forecasts and the process plant head actuals. These metrics have been used to identify key reconciliation issues and have initiated several studies into the causes for specific reconciliation results, which are discussed in the paper. In late 2020, a period of sustained poor reconciliation results led to the recognition that increasing the understanding of risk between the MRE and ORE should be investigated. To assist with modelling stope level risk within the mine plan and subsequent reconciliation, an attempt was made to develop a formula to quantify ‘stope risk’ from MRE metrics such as sample spacing, kriging efficiency and so on

Mar 22, 2022

By G Hill, D Grant, M Tyler

Located approximately 570km NNW of Adelaide in South Australia, the Olympic Dam mine (OD) is the world’s fourth largest remaining copper and gold resource and the largest uranium resource. Discovered in 1975 and going into production in 1988, the operation consists of a fully vertically integrated underground mine, mineral processing plant, copper smelter and refinery, as well as associated infrastructure. BHP achieved production of 203,000 tonnes of copper cathode plus associated by-products in financial year 2016. The immense size and high-grades of the Olympic Dam resource offer a range of growth pathways, making closure timing estimation and planning a challenge. Current estimates put the OD resource at approximately 79 million tonnes of copper. Major factors influencing the closure timing estimation, as a result of the large resource and grade tonnage profile, include the mining method that may be used and the downstream processing method, ultimately influencing such things as the total disturbance area and the extent of infrastructure to be demolished at the end of mine life. In addition, factors such as the mining and processing method and production rate have a direct impact on larger rehabilitation items such as the total number of tailings cells required.CITATION:Grant, D, Tyler, M and Hill, G, 2018. Olympic Dam mine closure planning process, in Proceedings Life-of-Mine 2018, pp 43–45 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By A Holmgren, W Forsling

In the present study infrared attenuated total reflection (IR-ATR) was used to monitor the rate of in situ adsorption of heptyl xanthate on a layer of zinc sulfide synthesised on a germanium ATR crystal. The zinc sulfide surface was characterised using x-ray photoelectron spectroscopy (XPS). The absorbance of heptyl xanthate measured increased with increasing bulk concentration of the adsorbate up to an equilibrium plateau value corresponding to a fractional coverage of the surface sites of the substrate. For the adsorption from solutions of concentrations between 10-3 and 10-5 M, the rate of adsorption increased with increasing bulk concentration. At higher concentrations the measured absorbance should be corrected for the absorbance due to the concentration of xanthate in bulk solution. The present work provides a discussion of this correction. Assuming the adsorption stage to be rate-controlling and proportional both to the concentration of the adsorbing species in solution and unreacted surface area, a rate law governing this type of transient adsorption kinetics was derived. By means of absorbance data for the concentrations 0.1 and 0.01 mM, the rate constant of adsorption was calculated. From the initial part of a Langmuir adsorption isotherm, the absorbance at monolayer coverage and the equilibrium constant of adsorption could be estimated.

Jan 1, 2005

By S Viviers, G Ratner

Ventilation is part of all underground mine operations and is undertaken in order to introduce fresh, cool air to the workings and to remove stale, affected air. It is problematic to obtain efficient and accurate estimates of volume flow and static pressure in the installed operational configuration for the auxiliary axial flow fans.An empirical method was developed to estimate the static pressure and volume flow through a calibrated differential pressure port on axial flow fans. Prior to shipping, each fan is performance tested according to BS 848 (ISO 5801) to establish the fan performance curves. In addition to the standard required parameters captured to fully describe the performance, the differential pressure is measured across the fan rotor to enable correlation with the characteristic fan curve.The method was implemented on a ruggedised tablet PC platform. This compact platform is then used to calculate the volume flow rate from the differential pressure sensor measurement input via a USB port. The result is a real-time measurement of volume flow and operating point of the fan system. This can be used effectively in overall modelling of the mine auxiliary ventilation systems and calculation of system resistance could provide a health indication of the fan and duct system.CITATION:Ratner, G and Viviers, S, 2013. Underground auxiliary ventilation monitoring and diagnostic system, in Proceedings The Australian Mine Ventilation Conference , pp 57-62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013