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By S Moradi

The thickener overflow of zinc concentrate, obtained from flotation process in the Angouran plant located in Iran, contains a large quantity of slimes which were transferred to the tailing ponds. These slimes have caused problems of storing and environmental aspects in the Angouran area. The objective of this research is to describe the extraction of zinc from these slimes by leaching method using sulfuric acid in pilot plant scale.Chemical analyses showed that these tailing materials contain 35 per cent of zinc. By XRD analysis, smithsonite is identified as the major constituent. Calcite, dolomite, and cerussite are found as carbonate minerals. A minimal amount of Zn occurs as hemimorphite. Quartz, kaolinite, clinochlore and muscovite are other silicate minerals in the slimes.In the optimal conditions, ie acid leach at pH of 1, temperature of 55¦C, reaction time of 120 minutes and solid-liquid ratio of 1:3 and neutralisation with Ca(OH)2 at pH = 4.5, temperature = 70¦C, time = 90 minutes, the total recovery of zinc obtained was 95 per cent.

Jan 1, 2004

Data collected from payload management systems at a number of surface mining operations show significant variance. Heavily loaded trucks travel slower up ramps than lightly loaded trucks. Faster trucks are slowed by the presence of slower trucks, resulting in 'bunching' and production losses. A stochastic model was constructed to simulate a truck haulage return cycle of 12.5 km at a large open pit gold mine in the USA. For a fleet of 35 trucks, the best estimate of the benefit achieved by a sustained reduction in payload variance of 25 per cent is a throughput increase of 1.6 per cent, within a possible error range of 0.6 to 3.2 per cent. This potential benefit is worthy of further investigation by Continuous Improvement teams at large open pit mines. The model also indicates that, under the right circumstances, provision of an overtaking lane can provide throughput benefits of up to ten per cent, The feasibility of providing unidirectional haulage circuits within large open pit mines should be examined.

May 1, 2010

By P Mikula, B Darlington, J Graham, P Young

In underground mines experiencing dynamic events, there is an ever-present challenge to design and maintain a capable ground support system. One key component of ground support systems is surface support, which serves the essential roles of retaining failed rock and transferring forces generated by surface displacement to rock bolts or other support elements. Observations underground show that in many instances, standard mesh panels alone do not provide sufficient dynamic support to retain substantial bulking failures imposing displacement onto mesh, and in such cases Mesh straps and W-straps may be employed. Determining the performance of surface support elements proves to be difficult, with a multitude of variables at play in the underground environment. Quite comprehensive work has been completed on laboratory testing of surface support systems; however, very little work has been conducted on in situ dynamic testing of Mesh straps and W-straps. In 2019 in Western Area’s Flying Fox Mine, in situ dynamic testing was conducted on a series of Mesh straps and W-straps using Sandvik’s in situ Dynamic Test Rig (DTR). The testing regime applied impact energies from 5.1 to 15.3 kJ to Mesh straps and W-straps. The performance of the straps that did not fail was a maximum absorbed energy of 9.3 kJ and 14.2 kJ for the Mesh straps and W-straps respectively. The testing successfully demonstrated the ability of Sandvik’s DTR to test not only rock bolts, but also surface support elements, creating new testing and research possibilities. The testing also provided important design guidance data that is not practicable to obtain using laboratory dynamic testing facilities.

Nov 29, 2022

By S H. Begg

There is strong evidence that many major oil and gas (O&G) projects are plagued by large cost and schedule overruns, or significant underperformance in productivity. Similar evidence exists for large mining projects. This paper claims that uncertainty is the underlying reason why projects fail to deliver the metrics used to justify their investment, or to deliver the economic value possible if alternative decisions had been made.Most technical and economic analyses are performed to reduce uncertainty to help make decisions. Decision-making is about ranking alternatives and choosing the best; rarely are precise predictions required, if this is even possible. Better uncertainty assessment is one of the keys to better decisions, thus better business outcomes. To get better decisions it is suggested that the focus or reward/penalty incentives be shifted away from the quality of outcomes to the quality of decisions. High-quality decisions are those that are generated from the skilled use of the tools, methodologies and processes from the discipline of decision analysis.Uncertainty is quantified by probability, which is a degree of belief in the truth/falsity of some proposition about a quantity relevant to a decision, such as volume of in-place resource, future price or action of a competitor. The probability a person ascribes to a proposition depends upon their information set; hence probability is subjective – it is not an inherent attribute of the quantity of interest or the physical system.The above simple observations have profound implications for modelling approaches, how they deal with uncertainty, the use of data to help assess uncertainty and the reliability of information provided by subject-matter experts. The limited circumstances under which frequency data (from spatial or temporal variables) can be used to assign probabilities is also reviewed.People, in general, are subject to a range of biases and cognitive errors. Research with O&G subject-matter experts shows that their expertise offers little or no protection from making errors in probability assessments and other judgements.CITATION:Begg, S H, 2016. Decisions, decisions – uncertainty, variability, modelling and psychology, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 9–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J Rola

This paper outlines a laboratory-based design method, founded in critical state soil mechanics, for identification of an appropriate compaction specification to ensure dilative conditions prevail across the design TSF stress range. The method makes use of the critical state line (CSL) and consolidation tests prepared at varying compactive efforts. The CSL and consolidation curves are plotted together in e-log p’ space, with the compaction curves transformed from vertical effective stress to mean effective stress using the coefficient of earth pressure at rest (K0). Consideration is given to the sensitivity of K0 as it is generally not available during the design phase. An example of the design method is illustrated with laboratory data.

Jul 1, 2021

By B Broad

"Establishing ventilation in the early stages of a new mine is an essential step to achieve scheduled outcomes that ultimately drive the financial success of an operation. If the primary ventilation is not in place in time to support a contractorÆs work output, then the ore delivery is likely to be severely impacted. Options to increase ventilation in order to address shortfalls are limited. This in turn can lead to reduced revenue generation at a time when a mine is at its highest capital outlay. This can have implications for any company, but even more for an explorer moving to producer. The ventilation put in place to cover the start-up period is also unlikely to cover any extended or increased load required to meet schedule delays.The following paper examines two issues in relation to ventilation with a focus on small to medium projects where the company is establishing a mine using a mining contractor. The issues being: potential impacts on the contract and tender process when using a mining contractor key mine design considerations, such as æcrunch timeÆ, as they interact with ventilation achieving a successful ramp up.A recommendation is made for higher levels of detail around secondary ventilation leading up to the primary fan installation. The information should be included as part of the tendering process and preliminary project execution planning. Understanding the æcrunch timeÆ concept can lead to strategies, as well as back up plans, to minimise any negative impact.By understanding key risks around primary ventilation establishment for a new mine, detailed design work can be completed where it is needed most. Value is added by reducing uncertainty and a payback with better contract terms and a more robust ramp up plan. This will improve the economic return for the company and reduce the risk.CITATION:Broad, B, 2013. Contract considerations and other critical ventilation aspects in achieving a new mine ramp up, in Proceedings The Australian Mine Ventilation Conference, pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 1, 2013

By S N. Donaldson, B L. Hollis, K Wynn, L Potts, M Evans

A real-time load-haul-dump (LHD) dispatch optimisation tool has been deployed at Panel Cave 1 and Panel Cave 2 at Newcrest’s Cadia Valley Operations. The tool, known as ORB, is the first known successful implementation of an optimisation-based, autonomous, real-time dispatch tool, custombuilt for underground mining operations. ORB can co-ordinate the optimal dispatch of LHD’s in a block cave to achieve a range of objectives while adhering to draw compliance and geotechnical constraints. It is an example of highly automated short-term interval control. This paper starts by outlining the pre-existing business planning process, detailing the simple logic that produced the daily draw order. Next, the motivations for a real-time dispatch tool are presented, drawing comparison to the limitations in existing planning processes and how these can be overcome through an optimisation-based, autonomous, real-time dispatch tool. Subsequently, the paper details the Ratio Bogging Draw Strategy, through which tonnes targets are expressed continuously on draw bells or draw points as a ratio of total cumulative cave draw. This signifies artificial planning boundaries are removed and that draw targets are linked within a cave; such that tonnes are unlocked by bogging other parts of the cave, instead of as a function of time. This creates incentive within the target mechanism for fixing and bogging struggling draw areas whilst allowing uncapped progress if all draw targets are progressing within compliance. Furthermore, the optimisation tool developed is outlined, including the data it uses and the objectives it optimises. Finally, detail on the improvements to operations the implementation of this tool has brought, and the business process change it has facilitated are presented using Newcrest’s Cadia Valley Operations as a case study.

Mar 15, 2021

In a country richly endowed in mineral wealth, Climax Arintco Mining Corporation's ICAMC) Dinkidi porphyry Au-Cu deposit in Nueva Vizcaya, Philippines, represents the most significant mineral discovery in this country in recent times. The deposit is located within a belt of young intrusive and volcanic rocks in the Sierra Madre mountain chain of north Luzon, a region previously unassociated with porphyry -style mineralisation.Since 1989, drilling of the Dinkidi deposit has outlined a resource of 124 million tonnes of 1.0 g/t gold and 0.4 per cent copper. Regional exploration throughout CAMC's 37 000 hectare FTAA has identified a further 16 potential porphyry-related deposits.

Jan 1, 1997

By Baafi EY

Geostatistics is now widely used in the mining industry in the estimation of ore reserves and terms like kriging, variogram and estimation variance are becoming well known. Ordinary Kriging (OK) has been found by some practioners to be a superior tool compared with other ore reserve estimators. However, kriging hasn't been the ultimate solution to difficulties which may arise in ore reserve estimation. Several additional geostatistical techniques have been recently developed for more efficient ore reserve estimation in some deposits, especially gold and other precious metals. These include indicator kriging and probability kriging which are useful tools to work with in a selective mining operation.

Jan 1, 1987

By S Davidge, J Pile, R Schumann, E Kepe, W Stewart, M Ridd, B Rathi

Geographical constraints, including steep terrain and high rainfall, at the Ok Tedi copper-gold mine in PNG’s Western Province present Ok Tedi Mining Limited (OTML) with significant challenges in mine waste management. Waste management includes discharge of tailings into the local river system and storage of waste rock from the mine pit in waste rock dumps which erode into the river system. Copper bearing skarn mineralisation is associated with a massive sulfide (mainly pyrite) deposit. Consequently, waste rock and tailings can contain significant amounts of pyrite. Without appropriate management, these waste streams represent a risk of producing acid and metalliferous drainage (AMD) when discharged to the river system. Throughout the life of the project, OTML have developed evolving strategies to manage mine wastes and mitigate AMD.

Aug 2, 2023

The Pilbara region, located in the north-west of Western Australia, is significant as the second-largest source of iron ore on the planet. Iron ore mines owned and operated by Pilbara Iron are located within the Hamersley Basin. This paper refers to the Greater Paraburdoo mines, the 4WEST and 4EAST pits, located on the southern margin of the Hamersley Basin. The groundwater model refers to ephemeral watercourses: Seven Mile and Pirraburdoo creeks, which are adjacent to the two pits, and Ratty Springs, located upstream from 4WEST and within Pirraburdoo creek. The spring and creeks hold cultural heritage significance for local Aboriginal communities. Two of these, the Gobawarrah Minduarra Yinhawanga (GMY) and Innawonga native title claim groups, initiated hydrological work on the two creeks and Ratty Springs, with the aim of determining the affects of dewatering on the natural water flows of these systems. The numerical model used to simulate drawdown in the Pirraburdoo and Seven Mile Creeks was derived from PMWIN Pro software and covered an area of 77 km2. The modelling period was from January 1998 to December 2004, and the prediction period was from January 2005 to December 2015. The model has four layers and incorporated effects caused by mining voids, 4WEST and 4EAST pits, creek bed material, weathered bedrock below creeks and surrounding banded iron formations (BIF). The model has been calibrated using the trial-and-error method set down by Middelmis et al (2001). The current dewatering schedule (12 ML/day) in the 4WEST and 4EAST mining areas does not affect the water table levels in the adjacent creeks significantly or for any considerable periods of time. However, changes to mine plans may occur, for example, in response to changed commodity price and may lead to significant increase in rates of vertical advancement. This, in turn, affects dewatering schedules, as greater vertical advancement requires increased dewatering effort. When an accelerated mine plan is applied to the model and dewatering rates increased to 18 ML/day, drawdowns in the creeks are more noticeable. The model has therefore helped to indicate the extent to which increased dewatering rates may be acceptable, especially in terms of immediate and longer-term damage to riparian species, ie Melaleuca and Eucalypt. Predictions from the model may also allow mine planners to schedule decreased rates of vertical advancement, where these are required to meet environmental constraints.

Jan 1, 2006

By M Podreka, P Merry, L van den Berg

Anglo Gold AshantiÆs Sunrise Dam operation is located in Western Australia approximately 55 km south of the town of Laverton. Currently, the mine is producing from both its open pit and underground operations and is planning a significant step change in underground production as the pit phases out. The mine ventilation system is arranged in three independent ventilation districts: Astro, GQ and Cosmo. The future ventilation infrastructure requires significant upgrades to keep up with the increased tonnage. In the short term, increased production is planned for the GQ district as well as for Vogue, which is an extension in the Cosmo ventilation district. In the long term, however, Vogue is likely to become the centre of attention for mining activity.This paper explores several ventilation scenarios which include upgrading the existing fan stations, rentals, establishing a common ventilation backbone, and establishing new upcast infrastructure for GQ to support the short-term production increase. These developments were modelled using ventilation network simulation software to determine airflow distribution and fan operating points for each option. For the GQ area, with its short-term increase in production, each option is evaluated for total owning cost by considering capital and operating costs over a three-year period. For Vogue, which is to become the main focus of mining in the future, a different strategy is followed in analysing the ventilation requirements. Instead of considering different short-term options, a number of staged upgrades are considered to achieve the desired production rates.This paper summarises the planning criteria, airflow requirements, ventilation infrastructure requirements, and economic analysis associated with the conceptual ventilation system design. It highlights how the best short-term ventilation infrastructure upgrades can be selected when considered in isolation but highlights that long-term production planning can have an effect on the decisions made in the short-term.CITATION:van den Berg, L, Podreka, M and Merry, P, 2013. Sunrise Dam short- to long-term ventilation planning, in Proceedings The Australian Mine Ventilation Conference , pp 107-114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By D Flint, O Rindriatmoko

PT FreeportÆs Deep Ore Zone (DOZ) Mine is the latest block cave mine within the East Ertsberg Skarn System (EESS).Issues with undercutting and stress concentrations at the extraction level were experienced, leading to reduced pillar strength.The extraction level-related issues became more pronounced, leading to local panel drift collapse, in an area that was over 100 per cent extraction. A review of ground conditions, panel collapse descriptions, and factors contributing to panel collapse are presented in this paper.

Jan 1, 2005

By Rajan S, Mainwaring P, Gould WD, Beaulne M

Polished discs of a complex sulphide ore were leached with three lixiviants; a mixed culture of Thiobacillus ferrooxidans and Thiobacillus thiooxidans, Thiobacillus ferrooxidanalone, and ferric sulphate. At either one or two week intervals the discs were examined by scanning electron microscopy, and the amount of soluble metals released from the discs were determined. The mixed culture solubilized more Cu, Zn and Pb than did either ferric sulphate or T. ferrooxidans alone. However, no differ-ences were observed between the three treat-ments by scanning electron microscopy during the first 44 weeks. The minerals were attacked in the following order: pyrrhotite, cubanite, sphalerite, pyrite and chalcopyrite.

Jan 1, 1990

Mr. Bradford said: - On assuming this chair, which has been oc- cupied by so many gentlemen of conspicuous ability, my first words must be an expression of the gratitude I feel for the honour you have done me in electing me to be your President for this year. When considering the subject matter of this address to you to- night, quite frankly may it be stated that for a long time I was on the horns of a very great dilemma, for while I could discourse on the modern political trend in relation to our industries at great length, it appeared to me that this was not the place for such a discussion.

Jan 1, 1987

By M Breen

In 2009, George Fisher mine began to seriously consider the transition from pyrotechnic detonators to electronic detonators. Initially, the electronic detonators were used for complex crown shots or areas where ground conditions had the potential for excessive overbreak. After critically evaluating the potential safety benefits, production increases and ability to redesign stopes to better manage a thinly bedded hanging wall, the mine decided to embrace the technology.

Nov 8, 2011

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 D McLaughlin

This paper points to the timely importance of commencing a centrally recognised perpetual collection of mineral specimens in the Northern Territory which has as one of its objectives the collection and preservation of Northern Territory minerals of scientific, educational and heritage value. Currently in the Northern Territory there is no government department or institution that has a resourced coordinated state-wide objective to collect and document collectable mineral specimens. Specimens held in storage by the Department of Mines and Energy and the Museum and Art Galleries of the NT are not catalogued and owe their existence to fortuitous circumstances, not as a result of a planned systematic scientific approach to mineralogy. Northern Territory mineral species and unique specimens have and will continue to be driven to extinction while no central and active, recognised repository exists. This situation persists despite the fact mineral production is the Territory's largest income earner. The paper presents the arguments that hopefully will assist decision-makers to commence development of a state mineral collection lodged within an appropriate institution in the Northern Territory.

Jan 1, 1994

An exploration and preliminary mine design contract was undertaken in Thailand to establish whether adequate lignite resources existed for the addition of future power generation plant through to the year 2000. The lignite ranges in heat value from 14 to 24 MJ/Kg (air dry basis) and occurs in 2 major seams consistituting measured reserves of 536 Mt (with an ash cut-off level of 45 % on an air dry basis) and a strip ratio of 4.1 bank cm/t. The paper describes the pre-planning, programming, equipment used, project management, logistics and exploration methods adopted to undertake the contract in a monsoonal area using Australian drilling and geophysical contractors.

Jan 1, 1983

By Y Pan

The recycling of steel is a crucial aspect of the shift toward a sustainable metals industry. The emphasis on steel recycling through the introduction of the scrap based mini-mill concept is also matched with a desire for greater product quality and reduced environmental impact, which, in turn, has generated important innovations. There have been significant advances in the technology for recycling steel over the last 20 years and this paper will provide an overview of these developments and discuss future directions in steel recycling including scrap management, control of tramp elements, electric arc furnace technology and ladle metallurgy.

Jan 1, 2004