Search Documents

By J P. van Dyk

A new crude ilmenite beneficiation process was recently proposed that allowed for the preparation of a smelter grade ilmenite from ilmenite with elevated chromium content. Magnetising roasting was not utilised in the process. As part of this circuit an ilmenite low susceptible reject stream was produced that had a low magnetic susceptibility. In this article a magnetising roasting process was investigated to beneficiate this material. Tests were conducted on material produced by pilot scale simulations on a typical South African East Coast heavy mineral reserve. The results obtained were compared to those published in literature for crude ilmenite. The small-scale experiments were used to define approximate operational limits for the oxidising roasting of a low susceptible ilmenite low susceptible reject stream, although industrial roasting conditions may differ significantly from those obtained in laboratory units. In a next phase these results will be confirmed on pilot plant scale.

Jan 1, 2001

By M Bettison, R Marton, R Wright, M Lowry

Depending on the geological setting, waste rock from mining can present risks to achieving acceptable closure outcomes. In the Pilbara iron ore mines, the majority of waste rock is geochemically inert. However, small percentages of pyritic material with the potential to generate acid and metalliferous drainage (AMD) require considered management within mine waste stockpiles designed to minimise AMD release to the environment. A larger percentage of waste rock has physical characteristics (e.g. erodibility) that may impact upon long-term landform stability. CITATION:Marton, R, Wright, R, Lowry, M and Bettison, M, 2018. The golden thread of waste characterisation from exploration drilling to waste rock placement, in Proceedings Life-of-Mine 2018, pp 90–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By E Wargem

The conventional method of underground mining involves a process known as drilling and blasting to excavate valuable ore bearing minerals through the load and haul process. Drilling and blasting processes are completed for both the development of the tunnels used to access the orebody and for mining out the orebody itself. The former being called development drilling and blasting, and the latter production drilling and blasting. In either development or production drilling and blasting, the effective recovery will be largely reliant on the extraction of the initial void created in each blast cycle. In development tunnelling, the initial void is commonly known as a Burn Cut. The initial void created in production drilling and blasting has many names such as a Slot, Winze, Rise or Raise. There are drill patterns and charge designs used to create these initial voids in the production cycle. This paper discusses common slot or winze designs for production drilling and blasting; and various critical design criteria for these. The document also aims to provide a process for completing desktop reviews of current patterns employed on-sites and provides an initial guide in a process for improving the recovery of a slot, winze, rise or raise in underground mines.

Mar 29, 2023

By P Worsey, B Lane

The recommended maximum explosive weight for boulder blasting using internal charges is 0.15 kg/m 3 (Olofsson, 1988). Normally this charge results in excessive scattering and flyrock, creating increased liability for the operator, especially in congested areas. An alternative technique using smaller explosive charges is being developed at the University of Missouri-Rolla (UMR). It is designed to reduce boulder scatter, flyrock and fumes and allows shooting in close proximity, using common blasting products. The method comprises drilling a hole into the top of the boulder, inserting a small primer, filling the hole with water and shooting it. The hole is drilled approximately two thirds into the boulder and the charge (10 g/m 3 ) is placed half way into the hole filled with water. Upon initiation the primer produces a small volume of gas at extremely high pressure which acts upon the surrounding (relatively incompressible) water. The water transmits this pressure to the surrounding blasthole, hydraulically fracturing the rock. As the fractures propagate and the boulder expands a rapid increase in the blasthole volume occurs. Because of the small charge the gas pressure quickly dissipates reducing rock movement, resulting in a fractured boulder with minimal material leaving the immediate vicinity. The current work includes both laboratory and field testing programs. The laboratory program is focussed on determining optimum parameters at reduced scale using concrete cubes. The field program focuses on determining a minimum powder factor and includes shooting smaller boulders up to 1 m 3 underground and 1.5 to 5 m 3 boulders in a surface quarry. In both cases the boulders were obtained as oversize from regular production blasts.

Jan 1, 1999

By A G. Guinea

If you were reading this article in a newspaper or similar in the 1800s, you would know that the world was firmly in the grip of the Industrial Revolution. You might have been one of the families that decided that an agriculturally based existence was no longer for you, and that the promise of a factory job was more appealing and more secure. And it was. Financially at least. Not so much from a workplace safety perspective.

May 5, 2022

By D P. Telionis, P P. Vlachos, R-H Yoon

Industrial processes involving multi-phase flows such as flotation require understanding of the relationships between bubbles, solid particles and the flow. Modern experimental tools are employed in this effort to measure with great accuracy the basic features of the motion of all three phases in turbulent flow. We employed a unique digital particle image velocimeter (DPIV) that can record with great accuracy and kHz temporal resolution, velocity vectors of all three phases, namely the fluid, the solid particles and the air bubbles. The interaction of these three phases was studied in homogeneous isotropic turbulence generated by cylindrical grids. Particles and bubbles were released into the turbulence and the motions of the three phases were monitored. The experimental results obtained in the present work were compared with the predictions of the models published in the literature.

Jan 1, 2005

By M Qiao, A Sugden, W Zong, J Hines, J Roberts, T Ren

Long-term exposure to respirable dust continues to present an occupational health and safety hazard to mine workers in underground mines. Workers who are exposed to mine dust can develop occupational lung diseases including coal workers’ pneumoconiosis (CWP) or ‘black lung’, progressive massive fibrosis (PMF) and chronic obstructive pulmonary disease (COPD). To demonstrate the exposure impact of certain working conditions and improve dust management in longwall development panels, this paper details the development of a computational fluid dynamicsvirtual reality (CFD-VR) based training tool. The tool has been developed as an educational platform to facilitate the effective communication of workplace health and safety (WH&S) dust control measures for continuous miner operators and engineers. The study introduces a promising approach to model ventilation and dust flow patterns based on site-specific data, employing computational fluid dynamics (CFD) for a detailed analysis and visualisation of these mechanisms. Additionally, an algorithm has been developed for processing the large and complex CFD data sets into a form amenable for visualisation within a virtual reality (VR) environment using standalone VR headsets with limited processing power. This training tool has been deployed to mine sites with the specific purpose of educating users on the hazards of dust emissions and the best practices for control.

Apr 16, 2024

Upon subduction, water is liberated from the sediments and the porous struc- ture of the oceanic crust and from de- hydration of minerals for redistribution and chemical reaction. A survey of pro- cesses which are likely to occur along the subducting plate reveals that water may well be basic in subduction induced gas generation, magma formation and ore deposition. In analogy to the industrial water gas process, reaction of water with car- bonaceous matter, in subducted sediments is likely to yield substantial volumes of hydrogen and carbon dioxide. While water and carbon dioxide appear to play a determining role in the development of differentiated magmas, hydrogen will react with metal sulfides and sulfur to form hydrogen sulfide which is essential in sulfide ore depo- sition. A survey of possible metal extrac- tion chemistry along subduction suggests a stepwise solubilization of metals from sediments and oceanic crust, and a poten tial accumulation of dissolved metals in zones of characteristic composition. The metal spectrum in ore deposits at near surface appears to reflect the com- position of the solution in the respec- tive subduction zone. A tendency for preferential solubi- lization of copper at subductidn level, from among the transition metals, an in- creasing generation of hydrogen sulfide in the sane direction and partition effects as well as sulfide precipitation characteristics lead to enrichment in copper and to its selective deposition in the direction towards the trench as observed in S. Latin America. A postscript deals with the formation of native copper.

Jan 1, 1986

By E P. O’Dwyer

Segment and gasket lining in tunnel boring machine (TBM) tunnels; and sheet membrane lining systems in driven tunnels are robust waterproofing systems each with a proven history of performance in Australia and further afield. Where an interface between these two systems occurs, the potential for costly failures is vastly increased and additional attention to detail is required in design, planning and construction. TBM cross-passages represent the most common occurrence of this interface, with steel compression flanges and neoprene gaskets being the typical means of connecting the waterproofing systems. There is a large variance in both detailing these flanges and associated outcomes, which makes this an area where there is room for improvement within the industry.The paper will look to tease out the various issues associated with this interface and how they can be dealt with efficiently with appropriate design measures, robust planning and carefully controlled construction methods.The paper will also look to review the new technologies and systems currently being put forward as potential alternatives, including an epoxy tape system, which has recently been successfully trialled on a project in Europe under high-pressure head.CITATION:O’Dwyer, E P, 2014. The challenge of waterproofing cross passages in segmentally lined tunnel boring machine tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 315–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By P Scholtz

Sustainability is one of those fuzzy words like innovation: everybody has an idea what it means, but if one starts asking for concise definitions then it becomes clear that everybody puts their own nuance on the meaning of these words. It’s not because these are difficult words per se, but rather because our understanding of them is highly dependent on the environment we work, live and play in. To remove any ambiguity and aligned with the risks that are faced by the human population today, the definition for sustainability that will apply for this paper is: generating value in the short term without destroying value in the long term.CITATION:Scholtz, P, 2018. Sustainable post-closure development – is it achievable?, in Proceedings Life-of-Mine 2018, pp 58–59 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By M R. Lane, M L. Cramer, N P. Wines

Increasing attention is being focused by regulators and industry on the residual environmental liabilities associated with mining projects following site relinquishment (termed surrender in Queensland). Even sites that have been rehabilitated to a high standard and to the satisfaction of the regulator are not completely risk free and may require some degree of ongoing management. As well as ongoing monitoring and maintenance costs, considerations should include how costs associated with potential risk event occurrence can be quantified and, if considered material, how provisioning should be undertaken to minimise the risk to the state and to taxpayers. In Queensland for example, once a resource site is fully rehabilitated and meets its environmental authority conditions or rehabilitation completion criteria, the tenure and environmental authority can be surrendered. During the surrender process any ‘residual risks’ resulting from the use of the site for the resource activity must be considered, and, if requested, a payment given to the government to cover any ongoing management and risk costs. Accent Environmental, in conjunction with Lane Associates, was engaged by the Queensland Government as part of the government’s financial assurance framework reforms to develop an innovative, ‘one-size fits most’ Residual Risk Calculator for the Queensland resources industry. The calculator is an Excel-based tool that uses detailed user inputs to estimate post-surrender management requirements and liability at resource sites. If residual environmental risks associated with rehabilitated mine sites can be identified, quantified and managed through pragmatic regulatory tools and effective provisioning, site relinquishment/surrender can be achieved without compromising environmental and social outcomes or exposing the state to unreasonable financial risk. The effective management of residual risk can also help facilitate operations as well as relinquishment/surrender of sites where a ‘walkaway’ solution may not be otherwise technically feasible.

Aug 2, 2023

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

By M Chappell

This paper describes the design of the steel fibre reinforced precast concrete (SFRC) segmental lining for the intake and discharge tunnels for the Gold Coast desalination plant in Queensland. In addition, the key design requirements and design methods for the lining of these 2 km long, 2.8 m internal diameter tunnels, including structural, durability and maintenance requirements are discussed. Details of the segment configuration and erection process are presented along with information on the manufacture and trial testing of the concrete for the segments. The paper also gives a brief introduction to steel fibre reinforced concrete behaviour. Construction of the tunnels commenced in April 2007, and the authors believe this is the first application of this technology in Australia.

Jan 1, 2008

By S Wainio, P J. Beckett, T Miller

Lichens are a symbiosis of fungi and algae. Air borne elements and gases are absorbed very efficiently over the entire surface of the lichen, because they have no protective structures such as a waxy cuticle or stomata. A survey in 1977 (one year before the Sudbury Regreening program began), indicated that several Cladonia spp had invaded the soil in Sudbury’s open birch woodlands. Pollution sensitive species such as Cladonia rangiferina and C. mitis occurred 20–25 km from the smelters. It was anticipated that the improvements in air quality and reclamation efforts would allow a natural invasion of pollution sensitive species into what once was a lichen desert that surrounded the smelters. The purpose of this project was to study the invasion of terricolous (soil-inhabiting) communities of lichens and mosses on reclaimed land in the Sudbury region 45 years after commencement of the Sudbury Regreening Program.

Aug 2, 2023

By J A. Meadows, M G. Annandale, G Castelain

Bauxite mining on Cape York Peninsula (CYP) commenced in the early 1960s in the region surrounding the town of Weipa. Rio Tinto Alcan (RTA) operates its bauxite mines on the homelands of 11 Indigenous Traditional Owner groups. The mining activity currently operates under three Aboriginal Agreements including an Indigenous Land Use Agreement – the Western Cape Communities Coexistence Agreement (WCCCA) – which provides RTA with access to the land in return for a range of benefits to the Traditional Owners, including employment, training, royalty payments and future relinquishment of the land (Klimenko and Evans, 2009). Despite reports of some ‘good progress’ in meeting the terms of the WCCCA (Klimenko and Evans, 2009, p 5), many of the region’s Traditional Owners remain dissatisfied. Two key areas of Indigenous community concern are the current premining management practices and the outcomes of post-mining landscape rehabilitation efforts.CITATION:Annandale, M G, Castelain, G and Meadows, J A, 2016. Sustainable mining – indigenous community benefit, in Proceedings Life-of-Mine 2016 Conference, pp 173–175 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By M S. Tuohy

Poorly judged or under-appreciated change plays a role in many major accidents. In particular, operational changes related to continuous improvement, maintenance and introduction of new technology can lead to unintended safety (and other) consequences. This paper provides an overview of the role of management of change in preventing unwanted impacts on safety, community relationships and the environment. It draws on a range of incidents covering mining, minerals processing, refining and smelting where inadequately assessed or ineffectively implemented change led to significant safety, environmental or community consequences. The paper will also highlight cases of well-managed complex change and the underlying model of decision-making in place to make those decisions. All these examples are drawn from Atturra’s experience in response to accidents or working with sites to improve their management systems. The paper will report on the challenges of applying conventional risk assessment approaches to complex or technically significant change. These typically result in either onerous and lengthy change procedures that are prone to workarounds or poor implementation. Conversely, ‘light touch’ or efficiency driven change processes present the risk of intended consequences by failing to bring appropriate expertise to bear in decision-making. Such balances can be resolved by considering the designation of ‘technical authority’ with appropriate expertise to consider the change and deconflict any production, cost or schedule trade-offs. Finally, the paper will reflect on the key components of management of change systems in the context of major accidents, highlighting good practice in how they are implemented. This will consider the integration of existing corporate processes, risk management and organisational structures into management of change systems, not just the content of change forms and procedures.

Apr 16, 2024

By Mahoney BK

The development of simulation models to reflect accurately the operations of a port and its associated transportation systems can be an expensive and time consuming process. However the complexity of such operations leaves little choice for other than simulation techniques since analytical methods are rarely appropriate. The development of suitable software has now reached the stage that these techniques can be used with confidence. Types of simulation models and their requirements are discussed together with the results from some recent applications to the planning and management of bulk terminals.

Jan 1, 1983

The sedimentery basins of this region developed in the collision zone of the Pacific Ocean plate and the continent. Stresses were transmitted thorough wedge-like lithospheric blocks, such as the Okotsk Sea, East Kamchatka, Aleutian and 2 other smaller blocks. Compression and inversion were more active at the boundaries: P ; P3 ; N1 ; and Z N in places. ? K2 P2 P3 N2 Tension, rifting and the increase in the rate of sedimentation were marked in '-2 , P3, Ni - N2, and also N2 - Q in places. Structural plan changes of the sedimentary basins and possible oil, gas and fluid migration occurred more actively 2 3 1 2 at the boundaries: ; P3 . N? , N1 N1 NZ N2 P2 P3 1 N1 'N 2 N3 Ni 1 1

Jan 1, 1995

It is indeed a pleasure to be here this morning to open the 4th Mill Operators' Conference. It is no mean feat to organise such an event and I would like to congratulate the committee for the work that they have done. I am sure that the Conference will be an outstanding success. I welcome overseas visitors and hope that they gain and share in the openness of this Conference. There is personal satisfaction for me to speak to you as a mining engineer addressing a large group of metallurgists and mill operators. I would have thought that it would be impossible for a mere mining engineer to inform a metallurgist of anything. I will desist from using such derogatory terms as "xanthate munchers", "bubble makers" and "glorified mathematicians". Terms of endearment as these may not be seen with much equanimity. Such is the warm association that the two professions have enjoyed over the years. The economic climate that we at present face is a major problem to all of us. I wonder how many people here come from mining operations that are in trouble financially or that are cutting back in one form or another. This is the recession that we needed to have. When the world's greatest treasurer can tell us that then we truly have a lot to fear. The present downturn can be seen as a normal adjustment in the cycle of our business. Yet the world does not experience such severe adjustments as frequently as we experience ours. The root cause for the regular adjustments can be placed at the feet of inflation. Until the politicians of this country of ours can come to grips with inflation, we will continue to experience downturns on a 5 to 7 year cycle. This, in my opinion, is the basic reason why we appear to experience more downturns than the rest of the world. We simply price ourselves out of the market. This takes about 5 to 7 years to be highlighted and then we need to make adjustments. However, this recession is worldwide. The adjustments usually take the form of redundancies, retrenchments and early retirements. What is the solution?

Jan 1, 1991

Tasker (1985) has detailed the accepted practices for constructing polygonal blocks of influerrce in the estimation of ore reserves. Further he suggests that users might fall into traps such as omission or overlap when determining the area of influence for each sample point.As an example of these types of errors Tasker (1985) describes under "Coverage ofthe Area" how 25 per cent of the exploration area will not be included in an equiangular triangular grid where hexagonal blocks of influence are used.The introductory suggestion of Tasker (1985) of "incorrect procedure" by Rudenno (1983) (and Armstrong (1983)) reiterated around the Figure 2a of Tasker (1985), is based on the brief description of the polygonal area of influence by Rudenno (1983). That description is not too different from that given by King, McMahon and Bujtor (1982).

Jan 1, 1985