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By R Bose, M Bovell, G Cheong

Grinding media is a major consumable in mineral processing and therefore decreasing costs associated with its consumption is regularly considered a key goal for the minerals processing industry. Grinding media manufacturers have historically developed steels with improved wear life for their products as a way of delivering incremental media quality improvement. This has included increasing carbon levels from low-to-medium carbon steels up to the eutectoid carbon composition of 0.77% where the relationship between higher carbon and better wear performance is well understood. Producers today will regularly use grades in excess of 0.8% to further improve wear performance particularly for rolled grinding media.This paper first introduces the demonstrated relationship between this increased carbon content and improved wear resistance along with metallurgical rationale behind the high carbon production process and limitations. To test the performance improvement associated with the higher carbon steel grade, a series of Marked Ball Wear Tests (MBWT) were carried out. This paper also explores the relationship between ball properties, test methodology and wear performance and concludes by correlating increased carbon grade with a reduced consumption rate of between 3.1% and 6.1% in the tests conducted.CITATION:Bovell, M, Bose, R and Cheong, G, 2018. Improved forged grinding media performance with carbon content greater than 1.0%, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 559–570 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Willis GM

The matte-metal-equilibria in the system Pb-Cu-S have been studied at temperatures between 720 and 920¦C by direct sampling and D.T.A. methods. These results are compared with those of other workers. The applications of such data to a continuous copper drossing process, and to a number of other metallurgical processes are discussed.

Jan 1, 1975

By P W. Cleary, G K. Robinson, M D. Sinnott

Discrete element modelling (DEM) is a research tool that involves numerically solving the equations of motion of large numbers of particles. It can be very useful for investigating mechanisms that can lead to bias when extracting samples from material as it is carried on a conveyor belt or as it falls from the end of a conveyor belt. DEM is more realistic than conceptual models and mathematical models; but it is not as realistic as physical experimentation. Its primary advantages over physical experimentation are that it is cheaper and that it allows many factors to be varied while keeping other factors unchanged.This paper reviews our investigations of the performance of sampling systems by using DEM. The sampling systems investigated include falling-stream cutters, cross-belt cutters, Vezins and a device called a ætrue-beltÆ cutter, which is being developed. The purpose of the review is to explain what DEM has contributed to the theory and practice of sampling, and to indicate what it is likely to be able to contribute in the future.CITATION:Robinson, G K, Cleary, P W and Sinnott, M D, 2012. How discrete element modelling is influencing the theory and practice of sampling, in Proceedings Sampling 2012 , pp 15-20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By Marshall T. E, Finfinger G. L

Gulf Coast domal salt mining operations have had sporadic encounters with methane gas emitted without any warning. In virtually all confirmed cases, the methane was localized in methane enriched zones. In a few cases large quantities of methane were expelled rapidly with salt outbursts, resulting in dangerous methane concentrations. Estimates of methane liberated by face blasts in methane-enriched areas is needed in determining how much air should be supplied to the face for proper dilution. A relationship between the gas content of salt samples collected from the face and the amount of methane liberated would be helpful in estimating how much methane will be produced by a face blast. Little is known about the layering or stratification of methane in large area-low velocity airways. This publication reports on three tests conducted by the Bureau of Mines which monitored the immediate return air of four faces during blasting. The test locations were in a methane gas-enriched section that had previously experienced two large outbursts and many smaller ones. A comparison was made between gas content values of face salt samples from the dissolution test and the gas liberation quantities. The characteristic movements of the methane in a large room with low air velocities were charted. This will help to better understand the factors involved in proper placement of methane sensors as a warning system.

Jan 1, 1988

East Nelson and Marlborough, in the northeast of the South Island, contain a wide variety of metallic minerals, including gold, silver, copper, chromite, antimony and scheelite, but no sustained metallic mining industry has evolved. Gold was the most sought-after mineral during the first century of European settlement and numerous discoveries were made but these failed to live up to expectations. While traces of gold are widespread in east Nelson, including in quartz veins in Nelson City, no payable deposits were found. In Marlborough the probability of a gold discovery had initially seemed remote but all this changed with the finding of rich deposits in the bed of the Wakamarina River in 1864, which provided a much-needed boost to the provincial economy. However, the decline of gold mining in Marlborough began virtually as soon as it had commenced. Extensive floods in 1865 hastened the exodus of miners to the profitable new fields of the West Coast.

Jan 1, 1993

By G S. Beros

In 2019 the Chinese Ministry of Ecology and Environment issued guidelines promoting the implementation of ultra-low emissions in the iron and steelmaking industry. These guidelines aim to drive improvements in air quality through the reduction of particulate matter (PM), sulfur dioxide (SO2) and nitrogen oxide (NOx). Secondly, it also represents an initial means to commence decarbonisation of the industry. The ultra-low emissions guidelines propose that well over 80 per cent of China’s production capacity will achieve these targets by 2025. In response, many sintering operations have implemented numerous improvements to the process that result in significant efficiency gains. Of note is the adoption of deep bed sintering where, with some modifications to equipment, the sintering bed depth is increased resulting in sizable reductions of SO2 and NOx emissions. This paper will also provide an overview of the requirements to introduce deep-bed sintering into an operation and highlight test work completed which quantifies the resultant reduction in emissions.

Nov 8, 2021

By M J. Nugus

The structural models developed by exploration and mining geologists are most commonly concerned with the ‘main structures’ or key constituents that pertain to the associated mineralisation. To this end, it is recognised that the geological and exploration models, which are developed, are essentially ‘fit for task’ and the scale-related variances are not always realised at an early stage. In fact, in many cases anomalous intercepts along different trends and of variable apparent continuity have often been neglected as ‘back scatter’ and not important. Recognition of the importance of subordinate structures as mineralising hosts suggests that additional opportunities exist outside the primary and main structures. History shows that opportunities are often not realised where gold is hosted in orientations not parallel to the predominant trend of the schistosity, main fault or shear zone.Another reason for the importance of subordinate structures can be understood from their roles in a percolation network. Subordinate structures can access the large fluid fluxes provided by backbone elements, but, as dangling elements, they provide greater opportunities for gold precipitation mechanisms and hence may constitute essential parts of the resource. Therefore, the role, understanding and consideration of the smaller-scale and orthogonal structures should be considered during all facets of exploration, resource development, delineation and mining.

Aug 22, 2011

By P Rubie, J Russell

This paper looks at the past, present and not too distant future of grinding mill relining.Since the adoption of autogenous grinding (AG) mills and semi-autogenous grinding (SAG) mills as the primary ore reducing devices in the comminution circuit, plant shutdown frequency and duration has largely been driven by the liner maintenance requirements of these mills.The past 30 years have seen the introduction of many technologies to reduce relining times and frequencies. Advanced relining systems have been developed which include single and twin Mill Relining Machines, capable of placing large (up to 8000 kg) liners, high energy recoilless THUNDERBOLT Hammers, and high capacity Feed Chute Transporters. Despite these advances, today many of the hazards associated with mill relining remain and reline times still vary considerably between mine sites. A sophisticated discrete event simulation program, designed to analyse the mill relining process, has revealed the dominant influences on reline times of crew performance and of the need for safe access to larger segments of the mill.A new generation of advanced and semi-automated technologies is currently being tested that will address these remaining challenges. These technologies remove people from the hazardous environment inside the mill and will allow techniques used in modern advanced manufacturing to provide a near-future step change in mill relining safety and performance.CITATION:Rubie, P and Russell, J, 2018. 21st century relining – the path to greater mine site profitability, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 621–640 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By S Azam

Coal is a vital energy source and source of carbon for metallurgical applications, contributing significantly to the world economy. Coal mining and processing involve multiple processes that generate Respirable Coal Mine Dust (RCMD), one of the primary sources of health hazards for coal workers. Since 2000, the rate of Coal Workers’ Pneumoconiosis (CWP) has continually increased in the U.S, with severity of the cases also worsening. Increasing evidence shows that exposure to RCMD in coal workers is a high-risk factor for lung cancer, which causes more deaths than the following three major cancers combined in the US Recent observations show an increased incidenceof CWP or other lung diseases, particularly among young miners in the Appalachian basin. The CWP prevalence in Appalachia is four times higher than the national average. Although various regulations are in place, the resurgence of such disease among coalminers demands additional efforts to better understand all the possible facets of coal dust toxicity, taking insights from current interdisciplinaryresearch efforts. One such important field is the interaction of coal dust with moisture in underground mines. Although moisture is prevalent and dynamic in an underground mining environment, it has never been evaluated for its impact on modifying the toxicity of coal dust and transport or flow behaviour. However, research conducted in atmospheric sciences in the past decade makes it clear that moisture in the atmosphere can significantly alter the behaviour of mineral dust. This paper is a part of research aimed at understanding how moisture interacts and alters the characteristics of coal dust. Such insight is crucial in understanding the potential toxicity of coal dust and developing mitigation technologies.

Oct 12, 2022

By T Roberts, D Faulkner, G Watt

Traditional mechanised resin rock bolting in hard rock underground mines requires the installation of resin capsules into a pre-drilled hole prior to the rock bolt being spun into a hole to mix the resin and set the bolt in place. In poor rockmass conditions, especially at depth or in highly altered faults and shears, the condition of the holes often deteriorates as the poor ground around it unravels and falls into the hole. This results in partially or fully blocked holes that either damages the resin capsule when they are being inserted into the holes or prevent it entirely until the hole is continuously cleaned of debris. This deterioration of the hole condition, and continuous need to clean and re-drill holes, also increases the diameter of the hole which in turn affects the continuously mechanically coupled anchorage mechanism of the rock bolt to the rockmass as there is simply not enough resin in the hole to fill the annulus between the bolt and the rock. This results in a large increase to critical heading cycle time and, more importantly, results in the rock reinforcement not performing as per design specification and increases the risk of instability. To overcome the quality control issues with resin bolt installation in poor ground, a single pass drill, install, inject and tension self-drilling resin bolt application was designed and implemented for use in such conditions. This system allows the operator to inject a two part polyester resin through a self-drilled hollow bolt to mix and fully encapsulate the rock reinforcement. The self-drilling bolt allows for post injection of the hole after the bolt has been installed into the rock and gives the operator manual or automated control on the amount of resin used in the hole to ensure complete encapsulation and continuously mechanically coupled anchorage to the rock. This allows the reinforcement to work as designed and provide the Geotechnical Engineer extra quality control confidence in these conditions. The implementation of this single pass resin bolting system resulted in significant decreases to the resin bolting cycle time and rock bolt quality control failures. In this paper the design, implementation and embedment into the development cycle will be discussed and the in situ quality control checks used to validate the increase in rock bolt installation quality will be shared. CITATION:Watt, G, Roberts, T and Faulkner, D, 2018. Single pass drill, install and inject self-drilling resin bolt application in poor ground, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 323–343 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By G R. Hancock, M J. Saynor, J B. C Lowry, K G. Evans, M Narayan

Tools such as landform evolution models (LEMs) provide a means of predicting how a landform may evolve over extended periods of time. Here, we utilise the CAESAR-Lisflood LEM to assess a proposed rehabilitated landform of the Ranger Uranium Mine in the Northern Territory of Australia (Figure 1). The environmental requirements for the closure of the mine state that the final landform must be able to physically isolate tailings material from the environment for a period of at least 10,000 years (Australian Government, 1999). However, uncertainty exists as to the reliability of model predictions representing thousands of years.In this study, we use model predictions from an undisturbed pre-mine landform to calibrate the parameters used in model simulations of a post-mining rehabilitated landform over a simulated period of 1,000 years. Specifically, we vary environmental conditions such as rainfall, presence/absence of vegetation and surface particle size characteristics in a series of model simulations to determine their impact on the respective landforms, to revise model input parameters as required. A simulated period of 1,000 years was used as it represents a period in which long term landform evolution patterns and trends may be established and identified. CITATION:Lowry, J B C, Narayan, M, Evans, K G, Saynor, M J and Hancock, G R, 2018. Using an undisturbed landform to calibrate long-term predictions of the evolution of a rehabilitated landform, in Proceedings Life-of-Mine 2018, pp 133–137 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

An experienced drill operator is able to make a log of a drill hole defining physical properties of the earth such as hardness or structure as they vary with depth. This log is based on intuition or how the drill æfeelsÆ. Rock characterisation using measure while drilling (MWD) parameters aims at refining this intuition into a package that accurately defines the properties of the subsurface as the drill bit propagates. Subsurface investigation using MWD parameters aims to combine physical drill parameters: Pull down force, rotary speed, penetration rate, torque and vibration in such a way to yield real time rock properties. MWD is investigation in its most primitive form, put simply MWD is merely a physical probe æfeelingÆ what the rock mass is at depth.

Jan 1, 2001

By M Tsai

Tube bundle gas monitoring systems have been used in the mining industry for over 50 years. The initial design was based on four individual gas analysers along with a series of solenoid valves, gas sample conditioning and flow control mechanisms to ensure the correct gas flow stream volume to the analyser. Simtars staff have identified flow control issues when providing operational support to coalmines on numerous occasions. The accuracy of the oxygen analysis is dependent on control of the gas flow to the analyser. Oxygen is one of the parameters used in calculating Graham’s ratio which is used for the detection of spontaneous combustion activity in coalmines. This paper will provide data which identifies the flow control issues by comparing mine site records for the two surface sample lines in the analyser room and the gas cage. Mine sites will be deidentified within the paper. The paper will discuss some of the changes that have been made in modern tube bundle systems and compare the change to the initial design specification developed by the UK National Coal Board, investigate possible operational impacts and provide a technical fix to solve the current flow issues being experienced at some mines.

Oct 12, 2022

By B Morey, J Gordon, P Mackenzie

Mount Tom Price Mine is peerless amongst Rio Tinto iron ore resources around the world. It has provided Hamersley Iron with premium quality, high lump yield haematite ore over the last four decades. The Brockman type bedded ore, containing bands of haematite and shale of varying thicknesses has been traditionally bulk mined to either high-grade or low-grade based on alumina cut-off grades. As open pit mining has progressed deeper into the orebody approaching the keels of the megastructure, increased structural complexity, chemical and physical variations in the ore, unfavourable ore presentation and reduced blending options have become an issue for grade control and may have serious impacts on product stockpiles. The grade blocks and boundaries must be accurately defined according to geological contacts and where identified, selective mining may be applied. Therefore in-pit geological mapping is the definite and ultimate guide to achieve target grades and grade predictions. Under this scenario, it is absolutely vital that the mine geology team ensures this geological knowledge is passed onto the related departments including mining crews as well as to the short- and long-term planners.

Jan 1, 2002

By M D. Goodz

MacPhersons Reward gold deposit is in a post-kinematic tonalite intrusion which is a setting different from many other deposits of the Coolgardie goldfield that are hosted in early Archaean tholeiitic sills or meta-sedimentary rocks. Gold mineralisation at MacPhersons Reward consists of auriferous quartz veins that are best developed in the tonalite but extend to the adjacent komatiitic rocks and along the lithological contact zones. The gold-related alteration halo is dominated by biotite-chlorite and pyrrhotite. Unlike many other Coolgardie deposits, the As concentrations are low.

Aug 22, 2011

By D E. Thorp

The mining and concentration operations of New Zealand Steel have been carried out initially from the Waikato North Head (WNH) deposit since 1969 and subsequently from the Taharoa deposit since 1972. Over the years the WNH operation has produced about 1.2 million tonnes of concentrate which has been converted into steel, while total exports to the Japanese Steel Industry from Taharoa reached five million tonnes in February of this year. Recent expansion plans both in domestic steel production and in the ironsand concentrate export market have made it necessary for the company to look closely at, among other areas, the mineral processing of the titaniferous ironsands in both deposits. This paper deals with the recent test work carried out at WNH and Taharoa on the use of the cone concentrator unit as a primary gravity concentrating unit ahead of the magnetic separation stages and as a cleaner concentrator following the primary magnetic separation.

Jan 1, 1977

By R J. Goldie

The Monty Copper Gold Deposit is an ultra-high grade mine in Sandfire Resource’s Doolgunna region which was completely drilled out and developed within two years of commencing mine development. During this period, a total of 986 grade control diamond drill holes were completed, assayed, and validated, 15 levels developed, and 3136 faces mapped. The aggressive schedule meant a high flow of geological data was produced, validated, and incorporated into regular geological model updates. To process this data at a rate which allowed for timely use, more robust data processing methodologies needed to be generated. A new validation system was implemented which required two levels of validation being applied to any diamond drilling update. Step one was the validation of initial physical data including survey pick-ups and logging. This was done prior to new drill data being added to the geological model. Step two was the validation of assay data which was required prior to resource estimation. The implementation of Seequent’s Leapfrog Geo modelling software also allowed for a more seamless and efficient modelling workflow. The use of the Leapfrog Geo vein systems allowed for more rapid generation of geological models which then afforded more time for stringent assessment of the mineralisation system. An example of this was the introduction of cross-shift peer reviews in which opposing rosters of geologists would rigorously evaluate the previous rosters work prior to reporting. This additional level of validation resulted in more robust geological models and the identification of new ore trends. This presentation will detail the evolution of the Monty Geological model from a simple tabular indicated resource into a complex highly refined measured resource. Themes will include how the model was produced using workflows developed and optimised to meet key deliverables.

Mar 22, 2022

By A Sinuhaji, R Poedjono, G Flumerfelt

PT Freeport Indonesia is currently building the DOZ mine. It is a 25 000 tonne/day block caving operation which is scheduled to reach designed production levels by the fourth quarter of 2002. This paper describes some of the issues and challenges faced by the operation when introducing a new undercut method part way through the project. Advantages and disadvantages are discussed as well as the expected benefits of the new method.

Jan 1, 2002

By L Eriksson, D Penn, J Appelgren

Atlas Copco, a leading supplier of equipment and services to the mining and construction industries, is consistently pursuing its strategy to offer the most productive and economical solutions by continuously offering new innovative products. These are, in most cases, developed and tested in close cooperation with demanding end users before being officially launched on the international market. The demands for higher productivity and improved overall economy have resulted in systems for automation of the drilling cycle and also tools for integrating the drilling equipment to the production control system used by the customer. In terms of improving the blasted material quality, the company has placed emphasis on accuracy in the drilling process and documenting what has been drilled. By applying state of the art technology to the common automation platform, developed for the surface drilling market, major steps in improving overall drilling productivity and blasting performance have been achieved. This paper will give some examples derived from the latest development of solutions for the companyÆs surface drilling products.CITATION:Appelgren, J, Eriksson, E and Penn, D, 2012. Rotary drilling automation increasing operator productivity and drilling quality, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 13-18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

Mining had a very considerable effect on the country's development. The visual evidence remaining is an integral part of New Zealand history. Early mining for manganese and copper in the 1840s was succeeded by alluvial gold rushes. These gave way to hard rock extraction, hydraulic elevation and dredging. Coal mining dating from the 1850s was fairly widespread. Other minerals were obtained on a small scale. Manufacture of mining' machinery stimulated industrial engineering enterprises. Schools of mines played a significant part in advancing technical skills and several remain as museums. Surviving mine structures and site relics are part of the industrial heritage signifying the technological and economic development of a small isolated nation. Some of these are described. Identification, recording and preservation where practicable is advocated.

Jan 1, 1990