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By C D. Pocock

Maintaining catch berm capacity in open pit mines through controlled blasting prevents production delays associated with managing risks associated with wall instability. A method has been developed to quantify the drill hole deviation of presplit holes at Century Mine. Different controlled blasting techniques are used to control wall quality and decrease the risk. The performance of presplit drilling, in terms of deviation from design has been investigated. A methodology has been developed to quantify the drill hole deviation in three dimensions. This methodology was converted into a series of algorithms capable of handling an extensive range of data. The methodology was applied to a case study at Century Mine to evaluate the performance of drilling on two presplit blasts. Overall, 67 drill holes were investigated in the case study. The drill hole deviation was quantified in terms of three parameters: skewness, linearity and drill hole deviation parameter. Methods for quantifying each parameter were developed. Skewness, a measure of the amount of curvature and linearity, was defined as the measure of the consistency of the gradient of the drill hole. Drill hole deviation parameter is defined as the average measured deviation of the surveyed drill hole position from the design position. Acceptable drill hole deviation tolerances for each of the defined parameters were developed by analysing drill hole deviation parameters with respect to implications to catch berm capacity. Verification of the methodology was confirmed through the comparing of the completed drill hole deviation results using both visual inspection and cross analysis for each of the three methods. Holes with an R squared value of less than 0.97 for skewed deviation were classified as having skewed deviation, while holes with a difference in gradient of 3.5 were classified as having linear deviation. The results show that 76 per cent of the drill holes had deviation. Of this, 19 per cent were skewed, 57 per cent had linearity and 12 per cent contained both skewed and linearity deviation.

Nov 8, 2011

By L Hussey

Mt Keith concentrator treats low grade disseminated nickel sulfide ore supplied from the adjoining open pit mine. It is a traditional crushing, two-staged closed circuit grinding circuit (SAG & Ball Mills), followed by a complex split-size rougher, scavenger and cleaner flotation circuit. In 2016, 10.5 Mt was milled, at an average head grade of 0.54% Ni, yielding 35 000 nickel metal tonnes in concentrate.Historical analysis of the plant data indicated that of all the nickel lost in the fines rougher circuit tails stream, 25.6% was recoverable in an eight minute laboratory scale flotation test. These results implied that this fine nickel was readily available for recovery in the plant, either through operational improvements or additional flotation capacity. With operation optimisation ongoing, and capital within the business focused elsewhere, plant personnel were challenged to think differently about improving recovery.In 2012, a separate project to improve plant recovery when treating high talc ore was completed. Amongst other vessels, this project saw the installation of two 150 m3 Outotec Cells to the scavenger section of the fines rougher, middlings and scavengers (RMS 1) circuit. Since installation, the operation of these cells resulted in difficulties immediately upstream with instability in the scavenger cells. It was therefore decided that these cells would be better suited to treating the fines rougher circuit tails.The alterations required to divert these flows were minimal, with the capital project totalling $220 000.In the two years since installation, the fines rougher tailings nickel grade has dropped by 9.9%. The scavenger circuit has also seen a 2.8% reduction in tailings nickel grade, and instability issues were immediately resolved. This project serves as a lesson in how existing plant infrastructure may be better utilised to maximise recovery. Although this is especially applicable when capital constrained, such re-appropriation can be considered at any point to maximise return on existing assets. CITATION:Hussey, L, 2017. Repurposing flotation capacity at Mt Keith nickel concentrator, in Proceedings MetPlant 2017, pp 254–258 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By T McLeod, B Catto

AngloGold Ashanti Australia’s (AGAA) Tropicana gold mine (TGM) geology department seized the rare opportunity of building a new geology department for a new operation: the philosophy, the people and the processes. Not satisfied with the status quo, or simply repeating what was familiar and already known, the vision was for an innovative, agile, multidiscipline, high performance team, capable of delivering on expectations.To achieve this, the geology department has operationalised key components of human resource management (HRM).This paper describes the operational design and implementation of key HRM components: job analysis, organisational design and organisational development. The benefits of this approach are presented in terms of engagement and autonomy in roles, opportunity for role variety and flexibility of the organisational structure. The result is a geology department that provides the functions of mine geology, resource development, regional exploration, survey, data management, geographic information systems (GIS), resource modelling, scheduling, sample preparation, resource coordination and hydrogeology, and even geotechnical engineering for a year!Considerations for application in other geology departments are presented in terms of fundamental requirements and lessons learnt. Fundamental requirements for success have been the sustained support of the general manager, valuing the scrutiny that comes with continuous improvement, high quality HRM systems and tools within the organisation, and a committed leadership group within the department. One of the most important lessons learnt is that a robust process of ‘induction to role’ is critical – the process of familiarising new starters with who we are and the way we work.CITATION:Catto, B and McLeod, T, 2017. Rewriting the rule book – geology organisational design, in Proceedings Tenth International Mining Geology Conference 2017, pp 137–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

The Quiruvilca district, located 80 km east of Trujillo in north central Peru (Fig. 1), has produced over eight million tons of Cu-Pb- Zn-Ag ore from approximately 60 veins since 1789. "Quiruvilca means "sacred tooth" in Quechua, the lingua franca of the Incas. The expression refers to a prominent volcanic neck exposed several kilometers northeast of the district. The district covers an area of approx- imately 24 km2. The mines occupy the eastern quarter; workings underlie 6.7 km2 with a developed vertical range of 280 m. All pres- ently operating workings are owned by Corpora- cion Minera Nor Peru S.A., a subsidiary of ASARCO Incorporated. The oldest rocks in the area are Lower Cretaceous clastic sedimentary rocks exposed 7 km to the east. Lithologies include sand- stone, siltstone, shale, coal seams, and carbonates (Cossio, 1964). These rocks were folded and affected by regional low-grade metamorphism during the early Tertiary, 40-65 m.y. (Hollister, 1977).

Jan 1, 1987

By A Bonani, R Molina, H Constanzo

With conventional undercutting sequence the infrastructure on the production level often has a short serviceable life before major rehabilitation is necessary and is characterised by high maintenance costs. The abutment stress zone is the main cause of this situation. The application of the pre-undercut caving method variant can increase the availability and utilisation of the production level When a pre-undercut is used development and construction are carried out underneath a previously undercut area, far away from the abutment stress zone, under more favourable stress conditions. This paper describes the design principles and the relevant results from the application of the pre-undercut variant over three years to the Esmeralda sector of El Teniente mine. The aspects described are the undercut-extraction, the undercut-development and construction distances, the geometry and drawbells opening, cave extraction rates, and the rate and height of undercutting.

Jan 1, 2000

By Yesil MM, Bozdag T

The swelling process is an impor- tant problem causing damages to the structures in or on swelling rocks, both during construction and operating life. To understand swelling problem, a number of testing methods have been developed by many researchers. In these studies, the swelling parameters, in most cases, are derived from oedometer tests. The swelling parameters determined from oedometer type tests represent one-dimensional behaviour (one-dimensional swelling law) therefore, it is quite difficult to extrapolate the oedometer type test results to the three-dimensional in-situ conditions. To overcome these problems, a three-dimensional approach is suggested for clay bearing rocks. Results of triaxial swelling tests conducted on marl from Dodurga Lignite Coal Mine are presented. Triaxial swelling characteristics of the marl are presented and design approach for tunnels is described.

Jan 1, 1992

By T Warren, A Dempster, N Barnett, J Oh, S Saydam

The influence of the insulating properties of lunar regolith was shown in the sub-surface temperature tests performed by the Apollo missions, with no significant temperature fluctuations occurring below 80 cm from the lunar surface even if surface temperatures fluctuated >200 K between lunar days and nights (Heiken et al, 1991). Key to the thermal insulation of the regolith is its low density near the surface having the greatest insulative effect with the lunar regolith becomes denser with depth. As the regolith becomes denser, the thermal conductivity of the regolith increases (Hayne et al, 2017). Thermal modelling software, Oxford 3D Thermal Model, which mapped the lunar surface temperatures effect on the thermal influence at the lunar south pole sub-surface over a lunar year found areas with brief illumination with surface temperatures >120 K could have sub-surface temperatures <112 K that can sustain long-term stable water ice at depths of <30 cm (Paige et al, 1992; King et al, 2020). Further to this, the observation of water molecules or other hydroxyls by the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA) in non-permanently shadowed regions (PSRs) on the Moon, indicated that water could be present beyond PSRs (Honniball et al, 2021). Using the Oxford 3D Thermal Model in selected regions in the lunar south pole, can provide insights into the location and depth of cold traps that could sustain water ice.

Nov 29, 2022

By B Jones, M Chappell

Permanent rock bolts used to support rock tunnels are required to perform for the design life of the structure as a minimum. Quality of installation is critical to the performance over the life of the rock bolt.This paper will present the findings from an in investigation into the integrity of rock bolts installed in an underground hydroelectric power station cavern and access tunnel. The 25?mm diameter rock bolts were installed 50 years ago, tensioned and post cement grouted. Due to a major machine upgrade the whole facility was subject to an asset survey. The owners are responsible for managing the risks associated with the failure of these rock bolts and ensuring the structural integrity of the tunnels and caverns is maintained to continue operations, protect machinery, assure production and more importantly maintain a safe working environment for all employees and visitors.To help manage risk a proactive approach is desired. To this end a test schedule using a non-destructive testing (NDT) system was carried out by Independent Integrity Testing Pty Ltd (i2t). The system used in this application was RokTel™. The system operates by applying a small axial impact to the rock bolt end and measuring the resultant acceleration response. The rock bolt characteristics affect the acceleration response.The data output from the system is analysed principally using Fourier Analysis (FFT) and sinusoidal waves. The energy generated in the bar, the rate of damping and changes in frequency are all assessed. Testing was carried out on 70 rock bolts within the tunnel and cavern. A selection were then over cored, photographed and documented. The data gathered from the testing is then correlated with physical evidence to establish a calibration for the remainder of the rock bolts and assess if this is a viable method for identifying defective elements, and what degree of accuracy can be achieved. The findings will assist with the future assessment of similar hard rock underground?facilities.CITATION:Jones, B and Chappell, M, 2014. The use of non-destructive testing to identify defective rock bolts – a case study, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 275–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By P Knights

This paper examines the process and specialised skills required to extract insight from data routinely collected by mine operations, maintenance, engineering and environmental departments. Typical insights include: enhanced understanding of root causes; recommendations for next best actions; and simulation of likely scenarios. The skills required for advanced analytics are not currently the domain of mining engineers. The professions required by tomorrow’s mines are likely to be diverse and multi-disciplinary, and will include control engineers, software engineers, mathematicians and statisticians. A case study is presented that correlates mobile equipment production delays with rainfall events across three mines on the east coast of Australia. One mine is shown to have significantly more rain related downtime than the other mines, providing compelling evidence to improve productive performance.

Nov 22, 2011

By T M. Campos, H A. Petit, L M. Tavares, R Olympio

Much practical experience has been gathered in the last 30 years of application of high-pressure grinding rolls (HPGR) integrated with ball milling in size reduction of fine iron ore concentrates. The company Vale S.A, in Complexo de Tubarão (Brazil), was one of the pioneers applying the technology prior to pelletisation with an outstanding size reduction energy efficiency in the circuit and a significant increment in the specific surface area of the product. Recent studies by the authors demonstrated benefits of modelling and simulation to improve the performance of HPGRs in this particular application, with the model being able to describe HPGR performance under different operating conditions and under variations of feed size distribution. Despite these important advances, this modelling approach has only been used offline and under steady-state conditions. The present work applies the modified Torres and Casali model proposed by the authors in pseudodynamic simulations. The ability of the model to predict the characteristics of the product in real-time is evaluated using data available online for the pellet feed preparation circuit. Results demonstrated the model capabilities to map the physical operation and give a realistic representation of the process. Additionally, the model is demonstrated to be able to support the pellet feed production by providing extended real-time information of the process, making it a useful tool for improvement of the operational strategies and process stability.

Aug 24, 2022

By S Prakash, P S. R Reddy, S K. Biswal, V N

The beneficiation potentials of two Indian iron ore slime samples by flotation technique using both cationic and anionic collectors are investigated. The direct and reverse flotation of slimes using oleic acid and dodecylamine as the collector have been studied using both conventional cell and flotation column to upgrade the iron content. The characterisation studies of iron ore slimes indicated that the samples are extremely fine in nature and contain substantial amounts of martite, magnetite, goethite, limonite, kaolinite and quartz beside hematite as the dominant iron mineral phase. The samples on average contain around 52 - 58 per cent Fe, four to seven per cent SiO2 and five to six per cent Al2O3. Taking into account the physico-chemical properties of the slimes, it is attributed that both the samples need to be deslimed by hydrocyclone before flotation. The results of both cell and column studies on sample I showed that a feed containing 57.5 per cent Fe could be upgraded to 65.5 per cent Fe at 50 per cent overall recovery with simultaneous decrease in SiO2 and Al2O3 content to 2.3 per cent and 1.8 per cent respectively by using oleic acid as the collector. In the case of sample II, it has been established that reverse flotation of silica is the better technique to improve both the grade and recovery of iron. Batch flotation studies in cell indicated that a product with 63.1 per cent Fe could be obtained at 40.0 per cent yield with 63.6 per cent iron recovery by the combination of reagents such as gum acacia, sodium hexa meta phosphate and dodecylamine. The performance of column flotation techniques is far superior to that of the cell with respect to both grade and recovery. The concentrates are found to be quite suitable for commercial exploitation as pellet feed.

Jan 1, 2005

By T Belligoi

Diamond cores and drill chips provide the only direct physical evidence for ore containing rocks. Early characterisation of cores and drill chips is important as it provides critical information for downstream processing. Traditional characterisation techniques include visual logging by a geologist or analytic and spectroscopic methods but they are time consuming and can miss some important textural or geomechanical features.The goal of this work is to evaluate the application of image analysis to iron ore cores and drill chips and to suggest improvements to existing core-scanning and chip monitoring systems. Two samples of massive ore differing by their mineralogy and texture, as well as two different batches of drill chips, have been imaged and analysed. Results are compared in function of the imaging system and the classification algorithms.As a conclusion, despite the necessity for more testing and improvements in calibration and lighting, it is obvious that image analysis technologies can bring a lot of useful information in the perspective of a geometallurgical mapping of the deposit.

Jul 11, 2011

SPOT imagery acquired in May 1986 of the areas that include the Dugald River lead-zinc lode, northwest Queensland, Australia and the Ngwenalekau copper deposit, Botswana has been evaluated and compared with LANDSAT MSS imagery of the same areas. The data have been processed using band combinations, band ratioing, principal components analysis and classificatory techniques and the outputs compared with those of geobotanical, geochemical and biogeochemical data as well as geological information. For both study areas the image processing techniques cited have successfully distinguished discrete vegetation associations related to discrete surficial and bedrock geological units; and, notwithstanding the sharp contrasts between the nature of the geobotanical anomalies that in both areas occur over mineralised bedrock in Proterozoic sedimentary sequences, they have successfully identified the areas of anomalous vegetation over the mineral deposits. Greater vegetational and geological detail is revealed than on outputs generated from LANDSAT MSS data [see Cole, 1977, 1982(a) and (b)]. The additional information yielded by SPOT imagery compared with LANDSAT MSS imagery results from its greater spatial resolution - 20 metres as against 79 metres - and from ti fact that the three SPOT MSS spectral bands - 0.50 0.59um, 0.615-0.68um and 0.79-0.89um - respectivelc cover those sections of the electro-magnetic spectrum in which leaf pigments, notably chlorophyll, absorption for photosynthesis and leaf cell structure strongly influence reflectance. This accords opportunities for the detection of reflectance aberrations caused by stress due to drought and/or metal toxicity as well as for the identification of anomalous vegetation communities of moderate sizr These cannot be accurately discriminated on LANDSA I MSS imagery on which only very large geobotanical anomalies like that over the Lady Annie phosphate deposit in northwest Queensland [Cole, 1977, 1984; Cole and Owen-Jones, 19771 can be detected.

Jan 1, 1988

By J Pearse, N Acosta, N McIntyre, M Angarita, L Camacho, C Huguet, D Arbelaez-Ruiz, J Ossa-Moreno, O Restrepo

Colombia is an example of a nation where mining makes a significant contribution to local and national economies. Due to the abundant resources present in the ground, there are good prospects for further development. However, the impacts of mining projects can include reduced access to good quality freshwater for other economic activities and/or biodiversity preservation (Ossa et al., 2018). As well as the water management challenges common to all mining regions globally, Colombia has particular challenges associated with its biophysical and socio-political traits. Land use change in many regions is dynamic including rapid development of agriculture and the development and abandonment of small scale mines. The value of ecosystem services provided by prospective mining regions also creates challenges in particular with regard to the p&#225;ramos, the headwater wetlands from which about 70% of Colombia’s water supply has originated (Cleef 1981). Colombia also has particular challenges related to strong preconceptions about mining and its impacts on water. On the one hand, there is recognition that new large-scale mines are important for Colombia’s economy; on the other, there is deep distrust of the sector’s ability to operate with minimal adverse impacts (Guti&#233;rrez-G&#243;mez, 2017). Hence, any impact assessment is likely to face high levels of scepticism and scrutiny. Summarising the work of McIntyre et al. (2018), this abstract proposes a framework for assessing and communicating risks to regional water resources arising from the impacts of mines. The framework outputs aim to provide government and other stakeholder groups the scientific evidence needed to inform their viewpoints about mining development in the selected region, and a baseline from which to design a program of priority scientific research. CITATION:McIntyre, N, Angarita, M, Acosta, N, Camacho, L, Pearse, J, Huguet, C, Restrepo, O, Ossa-Moreno, J and Arbelaez-Ruiz, D, 2018. A framework for assessing and communicating water risks in prospective mining regions of Colombia, in Proceedings Life-of-Mine 2018, pp 49–51 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

The creation of an accurate and precise enough database requires the collection of many representative samples, subsampling and assaying them without destroying their integrity. The selection and implementation of sampling protocols often lead to severe difficulties, making the unaware practitioner vulnerable to massive exploration, feasibility and operating failures. Therefore, there is no substitute for a good understanding of the Theory of Sampling (TOS). Either because of ignorance, or because of short-term economic reasons, failure to comply with many stringent conditions can be devastating for the validity of a feasibility study, leading to false evaluations, to the abandonment of a viable property, or to the exploitation of one that is not profitable. All these failures have something in common: insufficient duplicate sampling, subsampling and assaying were performed; very important, preliminary heterogeneity tests were never performed; for short-term economic reasons, poor sampling and subsampling protocols were selected, second-class sampling systems and weightometers were installed and poor preventive maintenance and cleaning were implemented;and sampling experts were called only when the project was obviously in trouble. The conclusion is clear: in due time, iterative auditing of sampling practices is an insurance policy against massive financial losses for the company involved. A complete, comprehensive 100 point checklist of sampling Quality Assurance and Quality Control is provided, so critically important details to ensure success are not forgotten.

Mar 1, 2010

Cobar Mines Pty. Limited (CMPL) uses sodium sulphite as the principal depressant to attain selectivity in copper flotation prior to sequential recovery of lead and zinc. The usage of sodium sulphite is examined both from a theorectical viewpoint ana from the manner in which the copper circuit at (MPL has developed. The results of relatively recent investigations, both in the laboratory ana the plant, are discussed aria shown to support the present operating Techniques.

Jan 1, 1983

By P Odins

Traditionally, stratigraphic deposits have been represented by a large number of gridded surface and product analytical models, related to each other by naming convention. This approach, though suitable for structurally simple stratigraphic deposits, does not lend itself well to addressing the complex style of stratigraphic deposits which are becoming more prevalent. In addition, the sheer number of individual gridded models involved makes it very difficult to keep a consistent audit trail of the overall deposit model. Recently, a new enhanced block model structure known as Horizon Adaptive Rectangular Prism (HARP) models was introduced to address these issues. An HARP model is specifically designed to allow stratigraphic units to be represented with virtually no loss of structural integrity, by allowing the tops and bases of the individual HARP blocks to ‘bend’ in concert with the input surfaces. By bringing together the best of grid modelling, triangulation modelling, block modelling and grade estimation, the HARP model opens up many exciting new opportunities for the stratigraphic geologist or engineer to take their model further than was previously possible. Examples of improvements in modelling methodology using a HARP model include: the ability to represent complex normal, reverse and thrust faulting; the ability to store thousands of additional analytical, geotechnical or calculated variables in each individual block; advanced visualisation, manipulation and plotting capabilities; and the ability to calculate volumes and resources against complex, three-dimensional (3D) solid pit designs. Finally, several ‘real world’ scenarios, illustrating how this advancement in modelling technology can benefit a wide range of mining professionals are detailed. These examples demonstrate how productivity gains can be made in both long-term resource modelling and short-term ‘week by week’ geological modelling as an adjunct to mine planning.

Aug 22, 2011

By D A. F Oliveira, C J. Parker

The role of the virgin in situ stress field in tunnelling projects is well known in the Sydney area. The effect of in situ stresses is mostly considered through the use of published relationships that describe the in situ stress conditions as a function of depth. Considering the significant scatter in the data, it is evident that by adopting such relationships, the designers are assuming an average distribution of stresses with depth that is generally a reasonable engineering approach; however, when building a geomechanical model, the tunnelling or geotechnical engineer needs to account for the interrelationship between ground conditions (rock mass quality – fracturing, strength and stiffness) and in situ stress, which may explain part of the stress data scatter. This paper presents an alternative approach for interpreting in situ stress conditions, valid for both Sydney sandstones and shales that focus on such interrelationship between in situ stress and ground conditions.CITATION:Oliveira, D A F and Parker, C J, 2014. An alternative approach for assessing in situ stresses in Sydney, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 189–194 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Bevan JE

The US Bureau of Mines is conducting research to improve the health and safety for underground coal miners, and the efficiency of the mining systems that are used. In 1986, the Bureau began a major research effort on the technology for computer-assisted mining systems for underground coal mines. The initial target was technology for continuous mining machines that would allow them to extract coal by computer-assisted operation. Technology areas being investigated include guidance systems, machine condition systems, computer systems, machine control, human-machine interfaces and planning. In each of these areas, individual system development has progressed to where underground testing of these systems will begin in 1991.In addition to coal extraction, the Bureau has also begun research for the development of technology for computer-assisted roof bolting. The Bureau is developing technology for a "smart" roof bolter that would be able to sense and analyze strata conditions to determine the requirements to provide a competent roof. The system would determine the location of the hole, drill the hole to length, and select and install the appropriate bolt.

Jan 1, 1991

It is often assumed that geotechnical investigations or studies for open pit mines are confined to providing a slope design. However in an operating mine, the design is only one component of a mine geotechnical program. Reviews of slope designs are ongoing throughout the mine life. The concept of Pit Slope Management has been formulated because the design only entails one component of a total program that contributes to a safe, efficient mining operation. Risk is a normal part of mining. Effective management allows the risk to be contained or controlled. If the slopes are not effectively managed there will be increased risk for the operation. Experience has shown that utilisation of Pit Slope Management coupled with a broad base of experience to define the key controls on stability, provides a pro-active, objective approach. The reasoning is deductive and relies on the behaviour of the ærocksÆ. Once the key aspects are defined, studies are well focused, implemented as required and the risks can be effectively managed. When the key controls on stability are poorly understood reasoning is typically more ægut feelÆ. Under such circumstances studies, if carried out, may meet short-term objectives but often ignore the long-term objectives. Hence the risk to the project is greatly increased. This paper presents several case studies highlighting the above aspects and present elements of the Pit Slope Management Program approach which have been successfully utilised by the author to manage risk in mining projects.

Jan 1, 2003