Search Documents

By B Green

With a focus on safe productive tonnes, there has been an ongoing drive to increase the productivity of the mining fleet across BHP Billiton. In response, a team from the Iron Ore business was formed to review all aspects of the end-to-end drill and blast process and to challenge conventional practices that limit production efficiency. As a result of the outcomes of this work, a number of initiatives were identified to improve operational practices that have also delivered significant cost savings.One such initiative was to increase pattern size to a minimum of 1 Mt where practicable, thereby creating ‘megablast’ as a new standard across all mines. To achieve blasts of this size, the team had to overcome the complex problem of integrating wall control into the megablasts.With traditional blasting techniques, the key strategy, which is also historically inefficient but was thought to be integral to having stable, safe walls, was to utilise the trim blasting/modified production blasts technique (ie narrow blasts along the pit wall designed to ‘peel off’ the material while minimising the effects of vibration and charge confinement on wall integrity).Small traditional trim patterns comprise three to four rows of production holes and one or two rows of batter/buffer holes of reduced diameter that require the firing face to be completely exposed before blasting. This is an extremely slow process that requires a lot of resources for very little tonnage while adding additional expense to the final cost per tonne.This paper will show how the megablast approach was developed to control damaging vibration and confinement effects, flyrock and fragmentation while having the largest possible blast that includes wall control. The new practice is based on a theory that involves the initiation point and control row being the second row of holes from the pit wall itself. Adjusted charges in vented batter and buffer holes help to achieve an optimal toe design, and at the same time create a zone of broken ground that absorbs damaging vibrations formed by the attached production blast of any size, whether it is a straight wall or a multi-angled complex pit shell design.Using the new style of blasting has allowed an increase in the size of the patterns from an average of 300 kt to over 1 Mt whilst maintaining pit wall integrity. Case studies will be presented showing drill, charge and tie-in designs with the presentation having additional blast videos, including overall shots of blasts and in-close footage of what happens behind the blast at the crest of the planned catchment berm.The paper will also demonstrate the flow-on effect of using this style of blasting to reduce operational costs associated with other downstream processes, such as the reduced requirements for pattern preparation, an increase in productive digging, reduced maintenance costs and a decrease in fuel burn for equipment.CITATION:Green, B, 2015. Megablasts – enabling technologies in BHP Billiton Iron Ore, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 599–606 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By S Bourke, R Stone, B Hill

Since Jameson Cell flotation technology was first installed in a coal flotation application in 1988/89 at Newlands Coal Handling and Preparation Plant (CHPP) there have been fundamental improvements to its design which has led to its current status as the leading technology in Australia for fine coal flotation. These improvements, which include key hardware modifications, consist of the re-development of the orifice plate to produce considerable increase in wear life and reduction in power consumption for a given air entrainment and a significant increase in the amount of air that is entrained. Modifications to the downcomer allow maximisation of residence time and air entrainment while changes to the feed and air distribution system allows a reduction in installation cost and a reduction of solids ingress into the air line. Additionally, operational improvements such as the use of recycle to maintain constant flow to the cell feed are discussed. The recent installation at Hail Creek in the Bowen Basin, which consists of three B6000/20 Jameson Cells (6 m diameter bottom-fed distributor with 20 downcomers) will be reviewed as a case study. The latest design and operability of the cells are summarised and compared against one of the original designs at Riverside CHPP also in the Bowen Basin.

Jan 1, 2005

By I Y. Maslov, S A. Gorinov

It was demonstrated that the stable propagation of the explosive process is possible in low-density emulsion explosives (EEs) obtained through mixing of emulsion with a significant amount of expanded polystyrene (or other similar) granules. Such a process takes place in the form of a detonation-like wave of emulsion drops in explosive gas streams flowing out of the high-pressure area of the reaction zone.Chemical reaction in such EEs takes place in the form of surface combustion of emulsion particles interacting with the gas stream.A method was developed for determining parameters of decomposition of low-density EEs, and it was demonstrated that a gradual pressure increase takes place in products during the explosion of such EEs.The performed analytical research allowed low-density EEs (obtained through mixing of emulsion with a significant amount of expanded polystyrene) to be recommended for smooth blasting.Industrial-experimental blasts at quarries of Ural and Siberia, with extreme positioning of sides and using low-density EEs, have confirmed the viability of the recommendations given.The obtained results are useful in the advancement of smooth blasting technology using low-density EEs.CITATION:Gorinov, S A and Maslov, I Y, 2015. Physical and technical evaluation of possibility using low-density explosives in smooth blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 555–564 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By R Russell

The relative infrequency of fatalities and other serious events can give them an appearance of being random, of being beyond any reasonable degree of anticipation and prevention. In fact, the vast majority of these events result from exposures that are identifiable, measurable, and manageable. The lessons of prominent incidents, such as the Space Shuttle Columbia, OxyÆs Piper Alpha, Esso Longford, BP Texas City, Massey Mine, as well as lessons from single fatality events, is that alongside the proximate causes of each incident, there also coexisted an underlying fabric of systems, mechanisms, and culture that allowed risk in the workplace to persist and often to become normalised. All of these ingredients of the organisationÆs safety fabric lend themselves to the influence and intervention of senior leaders. The difficulty is that traditional injury prevention paradigms are not sufficient for addressing the precursors that lead up to catastrophic and fatal events. A recent study of such events, led by Dr Thomas Krause concluded that the descriptive aspect of HeinrichÆs safety triangle is useful, but that the predictive aspect is not. The study surfaced reasons why a reduction in less serious injuries does not necessarily correspond to a proportionate reduction in catastrophic and fatal risks. This presentation expands on the findings to include the concept of exposure to the event potential linked to precursor events and the framework for leading an organisation to be both cognisant and effective in eliminating such events.CITATION:Russell, R, 2012. Shifting the cultural paradigm for the prevention of catastrophic and fatal events, in Proceedings International Mine Management 2012, pp 91-96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By M J. Davies, R S. Davies

Despite increased expenditure, the global discovery rate of world-class ore deposits has been in decline for over a decade (Schodde, 2017). Mineral exploration has traditionally followed an empirical approach, searching for evidence of mineralisation upon the surface of the planet, then drilling to define the extent of an ore body beneath the surface. As outcropping deposits in well-defined areas are depleted, there is a need for exploration to extend to less well-explored search spaces. One popular new frontier is exploration at greater depths beneath the Earth's surface. However, exploring for deep deposits with limited surficial evidence requires the implementation of predictive targeting methodologies (Hronsky, 2011; McCuaig & Hronsky, 2014). The Mineral Systems Concept (Hronsky & Groves, 2008; McCuaig et al., 2010) provides a framework for predictive exploration targeting. Ore deposit formation is recognised to be a focused mineralising event. These events represent self-organising critical systems and are underpinned by the interaction of complex, non-linear processes. Through the collection and analysis of datasets that map mineralising processes, it may be possible to predict the size and location of resultant ore bodies. CITATION: Davies, M J and Davies, R S, 2018. Beyond below-ground geological complexity: Developing adaptive expertise in exploration decision-making, in Proceedings Complex Orebodies Conference 2018, pp 95–98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By T W. C Stambolie

Coalmines, like any other mine, generally involve the classic three-staged approach to mining studies; namely concept, pre-feasibility study (PFS) and feasibility studies (Cusworth, 2012). Subsequent to these studies, and in instances parallel to these studies, the commitment to an environmental impact statement (EIS) is made in order to secure both state and federal development consent. In recent times, the sentiment to both mining and coal is changing whereby the traditional approaches to mine planning and economic evaluation is complicated by evolving environmental legislation, expectations and time frames. It is all too common to take shortcuts in the development of projects in order to create the perception of cost savings and expediting the delivery timeline. Atkins (2016) points out that: boards of so many small to mid-tier mining companies, and a few majors, focus on relentless project delivery too early in the project process, with so little time and effort applied to risk analysis and option development. Unforeseen risks can cost any timeline or budget far more than the effort required assessing and mitigating these. The ultimate risk to any feasible coal project is that of environmental approval and achieving development consent.CITATION:Stambolie, T W C, 2016. A black canvas – planning a greenfield coalmine in New South Wales, in Proceedings Life-of-Mine 2016 Conference , pp 31–35 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By D W. Stevens

Mechanical sampling provides a definitive value for the product sampled but the results are not instantaneous, meaning that decisions on process control can only be made hours after the sample is taken. Chemicals are added, tailings are sent to waste, stockyards are laid and the data for the decision-making is historical. Online analysers provide instantaneous information, allowing operators to make immediate and cost-saving decisions on the process. However, pending the specific online analysis application, there is a need for reference sampling for dynamic calibration/bias updating of the analysers so that they can deliver the desired precision and accuracy. What would be the economic justification for combining mechanical sampling with online analysis to reduce laboratory costs and provide immediate process control with certainty of accuracy? Approved sampling according to the Theory of Sampling, with immediate process control information.CITATION:Stevens, D W, 2014. Justification for integrating mechanical sampling with online analysis, in Proceedings Sampling 2014 , pp 135–138 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By I Onederra

A better understanding of the detonation performance of an explosive charge can be gained by directly measuring pressure, temperature and velocity of detonation (VOD). This is particularly important with explosives used in the mining industry because their performance is directly influenced by the degree of confinement given by the borehole diameter and the surrounding rock mass. A project funded by the Australian Coal Association Research Program (ACARP) was initiated in early 2009 with the view to design and build cost-effective prototype instrumentation to measure the relative differences in detonation pressures and temperatures of commercial mining explosives. The project’s primary focus was on low-density explosives. Low-density (also referred to as low shock) explosives have been available in various forms for nearly 20 years. There have been significant advances in the availability, reliability and flexibility of these explosives, which now offer a range of densities and degrees of water resistance. Their detonation performance is not well understood and cannot be accurately predicted with current ideal and non-ideal detonation codes. It was therefore viewed as important to be able to directly measure pressure and temperature during the detonation process of these complex mixtures in production blastholes. Identifying the pressure release patterns of both conventional and low-density explosives under different geotechnical conditions should provide the necessary information to both validate detonation codes and better define input parameters for breakage and fragmentation models. This paper gives a general description of the prototype instrumentation developed and reports on the results obtained to date in full-scale conditions.

Nov 8, 2011

Changes in prices and costs change the mineable grade and the profitabil- ity of an ore reserve. In a static world the grade required for an ore reserve is measured by the ratio: Cost/tonne of ore x 100 Price received/tonne of product and profitability by the ratio:- Price received/tonne of product Cost/tonne of product If the words cost and price refer to average cost and average price over some suitable period, say 3 to 5 years, the above ratios express the convent- ional wisdom of the mining engineer, and assume there will be no change in technology or politics.

Jan 1, 1979

In the Renison Bell area of western Tas mania, a series of Lower Cambrian quartzites, shales, carbonate beds ("dolomites"), cong- lomerates, tuffs and argillites have been folded into a broad monocline whose general strike is NW-SE, plunging slightly north and dipping NE. The downwarped eastern side of the monocline is disrupted by a steep (50-800) east dipping normal fault, known as the Bassett Structure, whose throw is in excess of 500 m. A series of flat north dipping normal faults, each with a throw of approximately 50 m, further disrupts the sequence. All major faulting was pre-mineralization. A cassiterite- bearing Devonian quartz porphyry body intrudes this Cambrian sequence 2 km south of the currently operating mine. Of economic importance is the presence of three carbonate beds in the sequence. These carbonates consist of a mixture of calcite, dolomite and siderite. The No. 1 (youngest) and No. 2 carbonate beds are each approximately 15 m thick and are separated by 20 m of hematitic conglomerates and tuffs. The No. 3 (oldest) carbonate bed is approximately 5 m thick and is separated from the No. 2 horizon by 50 m of dark grey, finely laminated shales and quart- zites. Whilst the carbonates are remarkably persistent over at least 30 km2, facies changes are common and as a result of these changes, the carbonates vary considerably in

Jan 1, 1973

By Hagan T. N, Tucker A. J

The Cumnock Open Cut Mine (COCM) is located in the Hunter coalfield in New South Wales. Five coal seams are being mined, mostly by drilling and blasting, loaders and excavators, and trucks. The annual production of coal is 1.3 million tonnes. Overburden and interburdens consist mostly of siltstones and medium to thickly bedded sandstones. The strata dip to the south-east at approximately four degrees. There are no major faults in the rock mass.

Jan 1, 1995

By Z Li, D Chalmers, J M. Tenney

This paper presents the findings and analysis of the investigation of effectiveness of thin spray-on liners (TSLs) as a gas management tool in underground coalmines. The project involves spraying TSL on the area surrounding gas drainage holes whereby the TSL acts as a thin membrane decreasing the permeability of the coal. This restricts air migrating through the coal seam and diluting gas from the drainage holes. There are a number of potential benefits from this technique but key points are that gas drainage holes produce gas with higher concentrations of methane. The design and execution of a field trial to investigate the effectiveness of a TSL on purity of in situ methane from gas drainage holes is presented in this report. For eight drainage holes, the results show an average increase in methane purity by 9.14 per cent and a reduction in air contamination by an average 7.93 per cent. Overall methane flow rate decreased by 27.6 L/s; however, flow rates were unreliable due to poor measuring equipment. For most holes, methane purity was not changed significantly; however, certain boreholes were responsible for most of the variation in methane purity. The boreholes showing a dramatic improvement in methane purity were likely those with intersecting cleats covered by the TSL. If the TSL was sprayed over more area, specifically in areas where the cleats are intersecting with holes, it is likely that purity of methane in the drainage holes will increase.CITATION:Tenney, J M, Chalmers, D and Li, Z, 2015. Thin spray-on liners potential in reducing dilution of in situ gas in underground coalmines, in Proceedings The Australian Mine Ventilation Conference, pp 323–328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By M Rauer

With a worldwide growing population the demand for higher living standards, food and the development of new technology is rapidly rising. To allow for a continuous growth, larger quantities of minerals and raw materials are needed at a faster pace. Different methods have been developed to access or tap ore more quickly, such as improved drill and blast operations, mechanical mining methods using equipment such as roadheaders (RH), longwall miners and other technical equipment. Another possibility to access and develop mines faster is the use of a tunnel boring machine (TBM).The historical usage of TBMs is surprisingly long, but the opportunity for technology adoption by the majority of worldwide mining companies remains largely untapped. Dozens of full face TBMs have been used by mines around the world, including two that will begin operation soon in Australia. TBMs have been used to safely and rapidly gain access to the orebody, or to expand access to the orebody to increase output by running a TBM along the edge of the orebody for several kilometres. These machines have also been used for ventilation and for conveyor tunnels for ore removal. They have been used to quickly excavate long and winding declines giving access to an orebody at several levels in a short period of time.Tunnel boring technology can be used for mine declines, mine access tunnels and all sorts of different mine designs and set-ups. TBM technology simply needs to be adapted to the mine conditions and, if manufacturers are involved early on in the planning process for mine development, the operation can be very successful. In some cases, historically typical mine designs may need to be re-thought.One mine, the Stillwater Platinum mine in Nye, Montana, is currently employing its fourth TBM in 25 years. Two were used to create tunnels running alongside the orebody, rapidly expanding access to the orebody in many locations for increased output. Two were used to create parallel access tunnels to a mine expansion at the East Boulder orebody; one tunnel is for conveyor haulage and the other for vehicular access. TBMs have been employed successfully many times to rapidly drive vehicular decline tunnels to multiple mine levels, such as at the San Manuel – Magma Copper mine in the USA. While TBM technology may not seem to be optimal for every mine, these success stories show that the method can provide vast benefits for the right projects.Early use of TBMs in extremely hard rock metal mines, in the 1960s and 1970s, had limited success since performance was low. However there have been great improvements made over the years in the strength of rock which can be excavated by TBMs with high performance. Other important improvements involve the provision of a safe work environment, safely and rapidly supporting the rock and predicting geology ahead of the TBM.This paper will briefly note the more than 20 TBM mining projects and highlight some notable successes. It will then go on to give a status report on the two active TBM mining projects in Australia and the difference between a TBM operation versus other excavation methods such as drill and blast (D&B) or RH excavation.CITATION:Rauer, M, 2014. Tunnel boring machines in mines – a?brief review of past use with a status report on use today in Australia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 663–670 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

In most mining operations the ore undergoes several processes such as drilling, blasting, loading, hauling, crushing, grinding and liberation to become the final salable product. Drilling and blasting is an important step in this process chain and itÆs results such as fragmentation, muckpile shape and looseness, dilution, damage and rock softening effect the efficiency of downstream processes. The value created per ton of broken ore is the difference between the price it commands when sold as the final product and the cost to produce it. Traditionally, the total process in the mining industry is classified into two groups as mining and milling. These are managed as separate cost centres inspite of the interdependency. Each process has a budget and production target and emphasis is usually on maximising production (tons) and minimising cost rather than the overall profitability of the whole business unit. The efficiency of each process is considered to be satisfactory as long as they are within budget and meet the production targets. The mine and mill managers usually try to optimise each process independently rather than the entire process. This paper discusses the potential pitfalls of decreasing the drilling and blasting cost per ton of broken rock without considering its impact on downstream processes. It introduces a holistic approach to blast optimisation by identifying and measuring the leverage that blast results have on different downstream processes and then optimising the blast design to achieve the results that maximise the overall profitability rather than just minimising the drilling and blasting costs. This paper demonstrates the benefits of such a holistic approach to blasting based on computer model simulations and field studies from metal and open cut coal mining.

Jan 1, 2001

By S K. Ray

Open fire in a mine gallery causes large-scale damage to property and sometimes precious lives. Such fires produce two distinct effects, the throttle effect and the buoyancy effect. These effects disturb the ventilation system of the mine. To understand the complex dynamic phenomenon of open fire and its effect on ventilation systems, a mine fire model gallery has been designed and constructed at Central Mining Research Institute, Dhanbad. Two sets of experiments at air velocities of 1 and 1.5 m/s were conducted in the gallery using coal samples from the Dobrana seam of the Raniganj coalfields. After about an hour of development of fully-fledged fire, heavy backlash, with smoke and fumes, was observed. At the time of backlash occurring the gallery was divided into two zones. In the region of the gallery from the base up to 1.4 m the airflow was normal, in the remaining upper portion the airflow was the reverse. Air quantity reduced substantially, while pressure dropped across the fire zone, the products of combustion (POC) and temperature increased during the period of the throttle effect. It has been revealed from these studies that with an increase in airflow, pressure drops across the fire zone, POC, temperature and reduction in airflow increases. This paper addresses the important design features of the gallery, the instrumentation system, the experimental procedure and assesses the effect of open fires on mine ventilation systems.

Jan 1, 2005

The Ladolam gold deposit, located on Lihir Island in PNG, is one of the largest known epithermal gold deposits, with a resource of over 37 million ounces. The deposit is characterised by a telescoped porphyry-epithermal system 2-rich sulphidic hydrothermal fluids capable of transporting significant quantities of gold, and the sudden change from porphyry to pithermal conditions caused by removal of the volcanic edifice. As magmatic ore fluids breached the surface, cool surface waters (seawater and/or meteoric) acted as a diluent. Although no other deposit is known with comparable geological characteristics and size, positive features that may be looked for in exploration for other like-deposits elsewhere include magnetite-rich alkalic volcanic rocks, large carbonate haloes, and presence of phreatomagmatic breccias. New discoveries may be recessive or undercover, due to the quartz-poor nature of the alteration.

Jan 1, 2002

By Ehlers HK

Mount Isa Mines Limited has 25 rod and ball mills of various sizes installed in two Concentrators at Mount Isa. A continuing investigation into installation, design and materials of liners for these mills has been in progress since the early sixties. Both manual and mechanical methods of liner installation are used and described. Materials for the various applications have been evaluated, mainly by field trials. Design of liners has also been evaluated by field trials and the history of trials in No.4 Concentrator is given. The purpose of the investigation has been to reduce the cost of mill lining and the life of many linings has been greatly increased as a result of this work.

Jan 1, 1978

By Scaife PH, Cripps Clark J, Cameron DB

Tuyere coke samples have been taken through the tuyere openings of B.H.P. International Blast Furnaces since 1978 with Whyalla No. 2 Blast Furnace taking samples on a regular basis since 1982. The degradation of coke during it's passage through the Blast Furnace can be measured and the relationships between these data, feed coke data and blast furnace operating data demonstrated. Tuyere coke sampling has been useful in revealing misleading external coke testing results and is still the method to monitor directly the performance of coke within the Blast Furnace.

Jan 1, 1987

By M S. Fenzel

Increased environmental regulations and pressures have created changing and new demands for tailings management strategies in a variety of mining applications. Critical among these items is the disposal of tailings as the pursuit of increased yields and lower costs have driven the application of different process technologies. With a number of technologies having a niche application focus, the belt filter press has been utilised for decades as a cost-effective and versatile option for dewatering different types of mineral tailings and other waste process streams. One of the critical advantages of the belt filter press is the technology’s ability to adapt and work in numerous plant designs, operating conditions and applications. As permitting and disposal options have become more stringent, plant designers, operators and equipment suppliers must develop comprehensive and site-specific economic, design and process evaluation techniques to ensure proper equipment selection and system design for belt filter presses or any other dewatering technologies. This paper will explore these techniques in relation to belt filter presses (with reference to other technologies) in a variety of different applications, along with other considerations to ensure a successful tailings dewatering system and disposal design. Summaries of equipment performance characteristics, operating and maintenance strategies and optimisation techniques will also be addressed in conjunction with the belt filter press’s adaptability to different plant designs and the resulting tailings characteristics.CITATION:Fenzel, M S, 2015. Analysis and adaptability of belt filter presses and other technologies for tailings dewatering over a range of mineral processes, plant designs, conditions, regions and operating philosophies, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 35–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By R Jacobs

"The Jaguar project is relatively unique in that it was evaluated, financed, built and operated to completion within the last ten years, providing the opportunity to holistically review and reconcile expectations against the actual outcomes. It is a case study that allows wider conclusions to be drawn with respect to the risks and opportunities involved with project evaluation and execution.Jaguar is located in the Leonora Mining District of Western Australia and was commissioned in mid-2007 as an underground accessed, single high-grade volcanic-hosted massive sulfide (VHMS) deposit with an on-site concentrator, producing copper and zinc concentrates exported via the Port of Geraldton to South-East Asian markets.The feasibility study (FS) had several iterations (JML, 2005a); the last dated July 2005 was specifically targeted to secure project funding, and summarised the reserves-only portion of the resource and its planned exploitation. The commissioning of the mine was the transition for the owner Jabiru Metals NL from junior explorer to producer and the project was the dominant asset of the company.Jaguar operated through several significant deviations from the linear project plan set out in the FS, including the Global Financial Crisis (GFC), a corporate takeover and disruption to the mine plan from the onset of material geotechnical issues. Whilst the GFC or mining disruption were not specifically predicted in the FS or peer reviews, the generic effects of the events were assessed in the project risk assessment and they influenced subsequent management decisions. In parallel to the internal project-specific risks, the short planned life of Jaguar was a risk to the continuation of the corporate entity which was being addressed by significant investment into brownfields exploration to extend or replicate the project, and ultimately added value such that attracted a corporate takeover.Holistically, the project delivered the returns predicted in the FS, but in a much different guise than was expected. This paper will describe the reality of operations compared with the study predictions and expectations through the perspective of the project and corporate risk assessment.CITATION:Jacobs, R, 2016. Jaguar base metals project case study – has reality reflected the study?, in Proceedings Project Evaluation 2016, pp 86–97 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016