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By Robinson T

The paper describes a spreadsheet system that enables selection of projects and companies that meet the user's corporate exploration and/or acquisition philosophy. A regularly maintained commercially available database has been used as the basis for this system. It provides an easily accessible efficient com- prehensive search method. The technique enables ranking by various criteria, both technical and financial, to provide groups of projects/companies that are of interest. Initially, target size parameters such as reserves, production and mine life are applied together with geological criteria such as age and deposit type; the significance of the targets in the context of the Australian gold industry is addressed.

Jan 1, 1988

By E Rubio, N Morales

Currently, mine plans are optimised by using several criteria as objective functions, like profit, life-of-mine, concentration of some pollutants, mining costs, confidence level or ore resources, with consideration of constraints related to production rates, plant capacities and grades. Whilst this approach is successful in terms of producing high value production schedules, it uses a static opening sequence of the drawpoints and therefore the optimisation is made within the level of freedom left by the original opening schedule, and as a result it is far from the true optimal value of the project. This paper presents a model to optimise the sequence of drawpoint opening over a given time horizon. The emphasis is in the precedence constraints that are required to produce meaningful operational sequences considering the exploitation method (panel or block caving), physics considerations and logical rules. Further on, while it applies the standard approach of maximising net present value (NPV), it considers other targets for optimisation, like the robustness and constructability of the plans. Finally, it applies the model to real data to obtain feasible plans by means of this model. The first tests were done varying the production capacity of the mine.

Sep 26, 2011

By J Franke, C Gonzalez

One of the regular tasks of geotechnical and mining engineers is the measurement and management of deformation in underground excavations. Although several methods are used to do so, the incumbent methodologies for monitoring deformation and ground support serviceability are limited to the use of visual observations or measurements at discrete points, resulting in a qualitative assessment only. The introduction of LiDAR technology allows a quantitative assessment across the entire excavation volume and its rock surface, by collecting a full three-dimensional image of the entirety of an excavation such as an underground drive, decline, or a tunnel. Comparisons between epochs of complete 3D data coverage allows for change detection over time that doesn’t feature otherwise typical omissions. The implementation of regular scanning has shown to be highly advantageous for mines with swelling or squeezing ground, but also at mines with rapid deformation. Despite the LiDAR potential, its adoption has been slow. A key reason for that is that working with point clouds is foreign to most geotechnical engineers. Point clouds have long been the realm of surveyors, but to fully adopt their use in geomechanics requires retraining, upskilling, and devotion by the individuals and the company. Sites are already stretched, so often there are insufficient resources to be applied to bringing the new technology into use. The solution to this hurdle is to partner with subject matter experts to achieve the desired high-quality outcomes without the commitment of time by geotechnical personnel. This paper presents a new solution of fully automated raw LiDAR point cloud data processing that not only enables geotechnical engineers to avoid having to learn unrelated skills by allowing for deformation monitoring without associated training or expertise, but it also provides instant reporting results as well as a sophisticated database with features otherwise not available. All data processing time and effort is completely replaced by an automated process which at the same time opens up the opportunity to monitor many more excavation volumes at a higher frequency than is possible with conventional tools and methodology.

Nov 29, 2022

By I Levy

At our Monkland Mine at Gympie, we operate a deep, narrow vein gold mine using hand held equipment, rail mounted haulage and narrow shafts. This is in many respects the old-fashioned way and is well suited most of the orebody geometry exposed to-date. We have also commenced some long hole stoping and we use alimaks for some jobs. The heart of our particular mining style is the employment and retention of experienced miners with remuneration based on productivity. We do our planning/monitoring/supervision down to the level of daily individual productivity. In focussing on cycles per se, we have chosen not to talk about drill and blast cycles or cycles for mine development, stope preparation or drawdown and haulage. Instead we have stepped right back from the operation as presently run and have adopted a very broad view of the mining cycle. We will in this presentation intertwine the ebb and flow of, exploration, project sponsorship, development, production and cash returns to owners. The time line considered spans both history and predicted future.

Jan 1, 1998

BHP-Utah Coal Limited operates 33 draglines of varying sizes in the Bowen Basin of Central Queensland. The group's operations with draglines commenced in 1963 with the establishment of opencut operations at the then TPM Moura Mine and continued through expansion of that mine, the commissioning of the Utah Development Company Blackwater Mine in 1968, and the subsequent establishment of six (6) other large opencut mines, all in the general area over the next fourteen years. These operations generally commenced with boxcuts on the sub-crop at depths of 15 to 25 metres. Over the years, depths have increased so that average depths now are in the 45 to 50m range. It was soon realised that dragline operations would have to be supplemented with additional stripping equipment. In 1981, a symposium "45m and Beyond" was held in Rockhampton to assess the problems associated with such "deep" stripping. Subsequently, dragline operations have continued and although addi- tional stripping capacity has been added, in many instances, draglines have been used and are being used to dig depths greater than 45m, some- times as much as 65 to 70m.

Jan 1, 1989

By Massacci P

A review has been made of the studies focusing on methods for the description of grain -size distribution after breakage and, separa- tely, of the degree of liberation of the miner- al species making up the various grain-size classes of comminution products. The purpose of the study has been to de- velop an overall model of the phenomenon which, owing to the very effect of comminution, leads to the formation of grains that are generally of mixed composition. A calculation procedure has thus been de- veloped for the liberation function taken as the assessment of the distribution of mix com- ponents in the products obtained after a commi- nution process. The aim is to identify a func- tion which may, to a certain extent, simulate the variation of the grade-recovery function of an ore in relation to its degree of comminu- tion. The numerical model thus obtained has been tested out on results obtained experimentally.

Jan 1, 1986

By B Wu, C Zhao, B Lei

At present, the friction factor is calculated by measuring pressure drop and airway configurations. However, the workload of on-site measurement is heavy, and the measurement results are easily disturbed by the external environment. In order to meet the need of intelligent ventilation to quickly and accurately obtain the friction resistance of roadway. Based on the important of roughness in Atkinson friction resistance formula, in this paper, fractal theory is used to characterise the 3D rough surface, and a method based on fractal dimension to describe the roughness of roadway surface and calculate the friction resistance was proposed. A computational model of friction resistance for fractal characterisation of roadway 3D rough surface was established. The parameters of the model were deduced and verified by using Nikuradse experimental data. The fractal dimension of roadway surface was calculated by 3D laser scanning data of Kailuan roadway, the established friction resistance calculation method was compared with the field resistance measurement results. It is considered that the calculation method of friction resistance based on fractal theory is reliable and can well represent the influence of 3D rough surface characteristics of roadway. The result show that the new established friction resistance formula compared with the traditional Atkinson formula in Nikuradse experimental, the average relative error is 6.874 per cent, and compared with the measured results of ventilation resistance in Kailuan experimental roadway, the relative error is 6.667 per cent. Comprehensive evaluation and analysis suggest that the new formula can well reflect the influence of 3D rough surface on friction resistance, combined with 3D laser scanning technology, the friction resistance of roadway can be calculated quickly and accurately. This research provided a reference for the key technology and theoretical development of intelligent ventilation parameter measurement.

Oct 12, 2022

By Z Terzic, M Schult, D Chu, S Macklin

The East West Link road tunnels are proposed to provide a connection between the CityLink toll road and the Eastern Freeway north of the Melbourne CBD. The alignment passes from Moonee Ponds valley beneath the Upfield Line railway cutting, Royal Park, the historic Melbourne Cemetery and beneath Alexander Parade rising to an eastern portal at Hoddle Street. The western (Royal Park) part of the alignment passes through the folded and faulted Silurian Melbourne Formation, which has been subjected to deep weathering since the Triassic.The Melbourne Formation in the Royal Park area is mainly characterised by interbedded sequences of siltstone and fine-grained sandstone. The beds are often graded and a clear boundary between the siltstone and fine-grained sandstone rock can be difficult to distinguish. Variation in lithology and the presence of structural geological features such as folds and faults have resulted in an irregular weathering profile within the Silurian rock; nonetheless the formation typically becomes less weathered with depth.Due to difficulties in obtaining reliable laboratory strength and stiffness relationships with weathering grade, in situ testing methods such as downhole shear wave velocity and high-quality pressuremeter testing are a useful aid to assessing appropriate geotechnical parameters for design.This paper presents an analysis of the variation in shear modulus of the Melbourne Formation, determined at small-strain (from downhole seismic data) and at ‘engineering scale’ strain (from pressuremeter tests) for extremely weathered (XW), highly weathered (HW) and moderately weathered (MW) rock. Estimates of small strain shear modulus (Go) obtained a range between 400 to 3400 MPa for these weathering grades. By comparison against the pressuremeter test data, reduction factors to be applied to these Go values to estimate shear moduli at engineering strain levels typically range between 0.10 and 0.35.The downhole geophysics undertaken in the Royal Park boreholes also suggests that there is an inversion in velocity between approximately 15 and 27?m depth below the top of the formation. This is thought to be related to the effects deep Plio-Pleistocene weathering, iron cementation of joints and increasing frequency of ‘non-healed’ joints in the transition from MW to slightly weathered (SW) rock.CITATION:Macklin, S, Schult, M, Terzic, Z and Chu, D, 2014. Strain-dependent stiffness of the weathered Melbourne Formation, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 179–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By G Zhang, I Glacken

Multiple indicator kriging (MIK) has been used in the minerals industry for some decades. As one of the non-linear estimation methodologies, MIK has advantages related to resolving multiple or mixed populations, high variability data and strongly skewed distributions. Applying the MIK methodology requires a lot more effort when compared to other non-linear methodologies, for example localised uniform conditioning. This is due not only to the variogram modelling for multiple indicators, but the validation is also very important because the panel model is fundamental for follow-up work, including the generation of recoverable resources at the local or SMU scale. Apart from this, only a few reported case studies of MIK have documented post-processing of the estimated modelled distribution, representing the probability distribution at point scale at un-sampled locations. The MIK post processing should include the change of support from the point scale to the panel scale, and then the extraction of quantile values from the panel conditional cumulative distribution function (CCDF) for localisation of grades into the SMUs within each panel, based on a ranking estimate marking the SMUs from high to low. In this paper, we present a case study on a gold deposit with the MIK method with full-post processing implemented for recoverable resources. The MIK point estimate was carried out with an indirect lognormal change of support from point to panel scale, and localisation was done with a custom script. The localised uniform conditioning (LUC) method was also applied for comparison purposes. The comparison shows that MIK has advantages compared to LUC when comes to capturing the high-grades, especially when mixed or varying anisotropy is present within the mineralisation.

May 24, 2023

Valuers of mineral properties should be aware that accountants are a major user of their opinions of value. Reliance by accountants can range from obtaining comfort that book values in balance sheets are not overstated to establishing values by which to assess the fairness of a takeover offer. Accountants using mineral property valuations clearly can't be expected to have the same level of expertise as the valuer and ""second guess"" the valuation. But they do have an obligation, under the ASC guidelines and their own professional standards, to'check the logic and reasonableness of the valuation before being able to rely on it. This means reviewing the valuation report for general sensibility, discussing the methodologies and assumptions with the valuer and being satisfied as to his competence and independence. This paper outlines how accountants use mineral property valuations, the level of scrutiny applied to such valuations and the problems commonly encountered in practice by accountants seeking to rely on them. The paper also explains how values of-mineral properties are established in company balance sheets and why these often differ, quite validly, from fair market values.

Jan 1, 1994

By C Catania

Mining companies and operations across the globe typically target best practice financial management, along with a focus on economically driven mine plans. Not only is this inherent in running a successful mining business, but also critical in addressing investor scrutiny. The standards for social and environmental practices is less consistent than this, with most companies adopting standards that are driven through legislative and compliance requirements of the nations in which they operate. Although there is still room for improvement, Australian is a country that stands at the forefront of social and environmental legislation, driving more sustainable planning practices for mining operations, with an ever-increasing focus on mine closure considerations. Of the many nations yet to reach such a legislative position, Kazakhstan is a place where some companies are driving towards world class standards beyond what is government mandated. CITATION:Catania, C, 2018. World-class mine planning for a sustainable future in Kazakhstan Mining, in Proceedings Life-of-Mine 2018, pp 6–7 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

The operation of cyclones and cylinders is briefly described and com- pared, and a number of recent applications in mineral, gold and coal plants discussed. The capacity of an existing pump and cyclone in a circuit can be sig- nificantly increased by retrofitting a cylinder in series to predensify the cyclone feed. The cyclone overflow product size can also be adjusted and controlled using a variable aperture valve between the cylinder and the cyclone. This predensifier-cyclone system has been used at plant scale to con- trol the pulp density of the feed to cyanidation in gold plants, to size flotation feeds before split conditioning and to deslime and classify in gravity plants. Application in a typical regrind circuit is considered. Cylinders and cyclones also have numerous applications in water management systems, e.g., degritting mine and plant waters to protect pumps, sprays and other equipment. Screen undersize and flotation con- centrate dewatering circuits are described to illustrate how suitable stream recycles can reduce water consumption, optimize fresh water use and improve efficiency.

Jan 1, 1988

By Upfold RW, Velzeboer MD

An underground mine fire will influence the ventilation equilibrium in several ways which results in a redistribution of the ventilating quantities and pressures throughout the whole mine. The ventilation carries the combustion products which constitute the greatest danger of mine fires through the mine and provides the oxygen on which the intensity of the fire depends. However, as a result of the ventilat- ion disturbances created by the fire, changes in airflow patterns can take place which are not always obvious, especially when the mine is being served by several fans. The use of com- puter simulation techniques allow for the likely effects to be tested and the different ventilation options to be evaluated as an integral part of the overall emergency/rescue planning and control procedures.

Jan 1, 1981

Underground mine ventilation is now com monly simulated on a digital computer. Such a programme, incorporating natural ventilation has been modified by others to account for methane emission and elevated local tempera- tures. At Wollongong University, the pro- gramme was further developed and extensive interactive graphics incorporated such that any view of the three dimensional mine could be viewed, and superimposed upon that view are areas where a nominated parameter has exceeded a particular value - generally at a nominated time after a particular event and usually a fire/explosion of one type or another. A further programme was developed such that up to 20 'times' could be examined at a particu- lar location after say, a fuel rich fire at some other place in the mine. The output from this programme includes a plot of methane 1, smoke 1, temperature, pressure and air flow versus time - a most useful graphic to observe the limits of safe attendance in a particular Airway.

Jan 1, 1983

By M Manefield, G Bournival, S Ata

Asteroids contain an abundance of valuable resources such as: nickel, cobalt, gold, platinum and rhodium. Whilst the consumption of mineral resources on Earth continues to deplete, meteoroids have the potential to become a significant source of minerals. Even though the minerals content of asteroids may be relatively high, the valuable minerals are more likely to be only a small portion of the total ore present in the main body. The ores must, therefore, be processed to extract the metals of interest from the waste. Existing terrestrial technologies rely on manipulating the physical and chemical properties of minerals. The application of these techniques to asteroids processing, however, is not straightforward due to the presence of different conditions such as zero gravity and lack of water in space. This paper discusses potential separation and extraction techniques that can be used for processing of asteroids.CITATION:Ata, S, Bournival, G and Manefield, M, 2015. Resource recovery in space, in Proceedings Third International Future Mining Conference, pp 275–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By G Hall

BHP BillitonÆs (BHPB) Yandi ore deposit is a channel iron deposit (CID) in the Pilbara district of WA. The ore is predominantly a goethite-hematite pisolite and overlays a clay at the base of the deposit. Knowledge of the location of the contact prior to mining is critical to maximise ore extraction and minimise contamination from and mining of the underlying clays which contain high levels of alumina. The contact between the iron ore and the clay is highly irregular. Traditionally the contact has been delineated by closely spaced drilling û this can be expensive and since each drill hole only provides a point sample measurement, irregularities in the contact surface can be missed. In September 2001, three high resolution geophysical techniques were trialled to see if they could be used to improve the efficiency and accuracy of ore delineation. The three techniques were resistivity imaging, ground penetrating radar and electromagnetic conductivity imaging. The resistivity data showed a favourable correlation with the available ground truth data from drilling. Using this ground truth data as a calibration, an interpretation of the depth to the base of the channel iron deposit (CID) ore was constructed for the areas surveyed. A significant attribute of the method is that the position of the base of the ore is imaged continuously along the lines that are surveyed rather than at discrete points. No continuous well defined ground penetrating radar (GPR) reflections were observed from the base of the CID ore. There did appear to be some correlation between the range of echo times that reflections were observed and the drill data, however the precision to which the range of echo times could be estimated was of the order of several metres and therefore not adequate to replace current procedures. The electromagnetic data showed good correlations with the existence of shallow clays but did not discriminate between variations in CID ore depth. This technique is therefore not suitable for mapping the base of the CID ore but may still be useful as a rapid tool for mapping the position of clay bands.

Jan 1, 2002

By Blair J. R, Barrett J. R

In many underground mining applications where-dry fill is used, only a token acknowl- edgement of the fill properties is given. It is the aim of this paper to induce mining engineers to consider dry fill as an engineer- ing material rather than a mass to place in unwanted voids. Dry fill is generally cheap, inert and readily available, but it can still contribute to mining performance. In particular, the choice of the dry fill becomes more critical as stope sizes increase, controlled choked draws are used or pillar recovery introduced. Selection must be initiated from an evaluation of the role of the fill in the mining operation. In most cases the fill must be chosen before quarrying begins and an investigation must be made of available sources and appropriate quarrying methods. Some of the properties of fill are described together with evaluation techniques. A com- parison of placement conditions is limited by the complexities of material flow and degrada- tion: However, field and model tests can aid interpretation in these cases. Examples are given of aspects of dry fill selection and their incorporation in mining design.

Jan 1, 1973

By E J. Hancock, K H. B Chu

Failures within hard rock underground excavations have historically been defined by a depth of failure, estimated in the field or through individual measurements, with a simplified failure geometry; such as 1/3 span, cubic or paraboloid. This simplified shape, volume and mass of failure is typically used to estimate in situ demand as a simplified discrete point. However, the highly variable failure geometry indicates simplified methods to estimate the mass can be erroneous in comparison to high precision LiDAR scans. Advances in technology have enabled the accurate capture of failure geometry and allow a far more accurate analysis of failures to be completed. This case study investigates a number of real-life failures to accurately define the failure geometry, the distribution of the failure parameters and compares this to traditional methodologies. This paper also outlines a suggested means of standardising failure geometry parameters whilst accounting for their variability.

Nov 29, 2022

Most compact bucket wheel excavators in use are in the small to medium range. Large compact bucket wheel excavators compete directly with con- ventional longer boom excavators which have operational advantages over the large compact. There are, however, situations where the large com- pact excavator is viable. In the development of these large compacts there are a number of technical features to be addressed. In addition the SECV now propose to expand the concept to a large compact bucket wheel excavator with a bridge and loading unit for their Loy Yang Open Cut.

Jan 1, 1989

Quality Assurance has become a buzzword amongst governments and industry. Notwithstanding the world class work done by its committees in developing codes of ethics and of practice in field geological handbooks, mining cost estimation handbooks, and reserve estimation, the AusIMM could better prepare its membership for QA. MICA could provide a simple set of guidelines to enable consultant members to develop their own QA procedures manual conforming to AusIMM Codes and to IS09003, and AS3903.

Jan 1, 1994