Search Documents

By J de Vries

Arthur Page, a past President of AT&T said:All businesses in a democratic society begin with public permission, and exist by public approval. Product stewardship in its most basic form is simply risk management applied to the products we produce. Conceptually it may be considered as a more expansive approach to many existing safety, heath and environmental programs. Key differences include the extension of responsibility beyond the direct control of management, and consideration of the implications your products and processes have on the broader community, as opposed to the confines of an individual mine site or operation. This paper reviews the processes used by Orica Ltd to manage its product stewardship program. OricaÆs product stewardship program is expansive and supports activities and business that range from manufacture and delivery of commercial explosives and sodium cyanide to mines throughout the world, supply and operation of municipal water facilities, and manufacture and distribution of consumer products such as household paints and adhesives. We highlight the development of the program through experience both good and bad, and by use of case studies to illustrate how an active product stewardship program is an effective business risk mitigation strategy.

Jan 1, 2006

The need for a carefully prepared set of special conditions, to be used with general conditions of contract or, alternatively, a purpose written contract for adoption in tunnelling work in Australia is discussed. Recent decisions on the proprietor's liability for tender information and arbitrator's power to award interest are examined. A new clause for inclusion in contracts specifically giving arbitrators power to award interest is suggested. Similarly, a new clause covering delays due to environmental disputes is suggested, particularly for marine outfall tunnels. An alternative method for the settlement of disputes by negotiation is suggested for consideration and contracts and contract administration are discussed as the possible weak point in the construction process. At the conference it is intended to present a method or process to be used in contract administration which should reduce disputes, result in a better quality and efficiency of administration and ultimately in better contracts'.

Jan 1, 1981

By E S. Bernard

Steel fibre reinforced shotcrete (SFRS) is increasingly being used as ground support in both civil and mining applications. In recent years, methods of assessing the performance of SFRS have been developed. These include the beam test such as that prescribed by ASTM C-1018 and the panel test prescribed in the EFNARC European Shotcreting Standard. The panel test has gained popularity in recent times due to the two-way action modelled in the test. However, some difficulties have been noticed. Shear failures sometimes occur and there appears to be a rather high degree of variability in the panel test results. A new method of testing panels has been proposed. A circular panel supported on three symmetrically arranged points has been assessed at the University of Western Sydney. This paper describes the new test which may be the basis of a new specification for the testing of toughness of SFRS and summarises research work which has been carried out to-date.

Jan 1, 1999

By Wencai X

The conversion relationship between the Bond Work Index W1, specific output of mill and the energy efficiency of grinding were developed using dimensional analysis. These relationships were validated and the value of the conversion coefficient ~ was also obtained using a new installed device for measuring grindability of ores. With the new simulating algorithm the mill specifications, output and size distribution of grinding products of industrial mills can be calculated based on laboratory measured results. This algorithm is more accurate and simpler than any of the other empirical relationships. KEYWORDS: Conversion coefficient method, grindability, grinding Constant.

Jan 1, 1993

By O N. Antzutkin, W Forsling, K J. Pike an

The adsorption mechanism of three different O,OÆ-di-alkyl-dithiophosphate (dtp) collectors, K[S2P(OR)2] with R = Et, i-Bu and i-Amyl, on the surface of synthetic chalcocite (Cu2S) was studied by means of solid-state 31P CP/MAS NMR spectroscopy. The morphology changes on the conditioned Cu2S surfaces, in the collector concentration range 0.1 - 10 mM, were also monitored with scanning electron microscope (SEM). In order to assign Cu(I)-dtp species on the surface of Cu2S, the corresponding bulk Cu(I)-dtp compounds, which are clusters of the monovalent copper containing either Cu6(antiprismatic) or Cu8(cubic) cores, were synthesised, and characterised by means of solid-state 31P CP/MAS and static 65Cu NMR. Further investigations on the crystal habits of the bulk systems were carried out by powder x-ray diffraction and SEM. A comparative analysis of the 31P chemical shift and chemical shift anisotropy (CSA) data estimated from the experimental NMR spectra of the polycrystalline bulk Cu(I) dialkyldithiophosphate complexes was used for assigning the 31P resonance lines in the NMR spectra of the collector treated Cu2S powder samples. The species formed on the synthetic Cu2S surfaces were assigned to polycrystalline phases of: Cu6L6 with L = Et2dtpû, Cu6L6 and Cu8L6(S) with L = i-Bu2dtpû, and Cu8L6(S) with L = i-Amyl2dtpû. A heterophase autocatalytic step process of both formation and growth of solid CuxLy (L = R2dtp, x = 6 or 8 and y = 6) complexes on the collector treated Cu2S surface is proposed. A possible role of the oxidised form of dithiophosphate collectors, bis[di-alkyl-thiophosphoryl]-disulfane (disulfide), is discussed in terms of a specific self-redox reaction. The second order quadrupolar lineshapes in 65Cu NMR spectra were simulated and the interaction parameters, CQ and hQ, for the bulk dialkyldithiophosphato-copper(I) complexes were obtained.

Jan 1, 2005

By E Villaescusa, C Drover, I Onederra

Development face destress blasting is a construction technique in deep mining, which aims to prevent, reduce the frequency, or manipulate the timing of violent, stress-driven rock mass instability at the face. This paper presents a destress blasting design concept that was optimised for the specific rock mass conditions of a deep mine using the Hybrid Stress Blasting Model (HSBM) software. The design was then implemented in an area of the mine where stress-driven instability of the face regularly occurred during development. An adjacent tunnel was constructed in parallel without destressing, within the same rock mass conditions, as a control. The rock mass response to each excavation was quantitatively compared using high-resolution local seismic monitoring. Visual observations of the fractures created by destress blasting were also made. The analysis indicated that destressing reduced both seismicity and the rock mass stiffness ahead of the face. This was inferred from the spatial broadening of the development seismogenic zone and the typically significant reduction in the spatial density of seismic events. Seismic source mechanism analysis also indicated that destress blasting generated a much wider variety of failure modes than conventional blasting. Most seismic source mechanisms following destressing were associated with natural joint structures. A relatively small portion were consistent with newly created blast-induced fractures. The greater diversity of rock mass failure modes associated with destressing implied a lower potential for stain-energy accumulation within the rock mass at the face, and thus a lower risk of hazardous instability. Observations of visible rock fracturing indicated that the major principal stress influenced the damage intensity on natural geological structures within the destressed zone, and that numerical predictions of radial fracturing limits made by HSBM analysis were realistic representations of the real blasting performance.

Nov 29, 2022

Competition in the mining industry is the main driving force for both equipment manufacturers and end users to develop and apply the most cost efficient solution to a mining problem. Therefore the challenge to find new solutions is usually met by several suppliers under various factors of influence affecting specifications. Time and timing are particularly important, but all new developments ultimately have to successfully perform on site.Consideration of all aspects of planning, manufacturing, user liaison and ultimate satisfactory commissioning hinges on the necessities of assessing of all the expectations in the mining application and the requirements of the concept and layout team. To apply the maximum available technical competence with solid thorough workmanship is the best possible foundation for success of underground machinery development.

Jan 1, 1991

By A S. Lund

Optimisation of the underground mining production process benefits from informed decision making during the process of explosive rock fragmentation. Selection of the most appropriate bulk explosive products for underground production blasting is an area of endeavour that offers significant economic upside if correctly and thoroughly undertaken. The explosive selection process is facilitated by a clear understanding of:the physical and detonic properties of the alternative explosive options available; the response of different rock masses to these different explosive options; and the importance of maintaining a clear focus on desirable blast outcomes in order to enhance value creation aspects of the mining production process. The level of understanding of these issues is raised through the application of measurement and modelling technology, quantifying the effects of blast design (and implementation) on process outcomes. Homestake Darlot and DynoConsult applied a range of dynamic blast measurement and outcome modelling techniques in order to explore the relationship between rock properties, explosive properties and mining process efficiencies. A campaign of vibration and explosive Velocity of Detonation (VoD) measurement produced feed data for use in vibration and fragmentation modelling during the extraction of one of the major stoping blocks at Darlot Gold Mine. The paper describes the use of these tools and discusses the understanding gained concerning the limitations and capabilities of, and the reconciliation between, a selection of analysis and modelling approaches.

Jan 1, 2001

By D Cioclea, I Toth

Coal mining can lead to the occurrence of spontaneous combustion events. If these events are not prevented they can give rise to fires that have major adverse effects on the mine plan. After studying the chemical structure of coal, the theories of self-ignition and of the oxidation reaction of the organic compounds, two new technologies have been developed for fire prevention based on the inhibition of coal oxidation. The first technology consists of spraying water drops mixed with inhibiting substances into goaves. The second consists of the infusion of a mixture made of several chemical compounds. Tests performed in situ showed the new inhibition technologies to be highly effective even for longwalls mining coal with a high reactivity from the point of view of self-ignition.

Jan 1, 2005

An enormous capital outlay is required to bring a new deep level (¦ 4 000 m deep) Witwatersrand gold mine into production. In addition, future mining methods must cater for rapidly rising working costs of which labour costs make up the largest portion. South African mining engineers are therefore being forced to challenge accepted design and valuation principles when planning these high risk ventures. New mining methods must be sought to satisfy the ever increasing need for productivity improvement. The technological problems posed by such changes cover a wide range of disciplines. Aspects of shaft design and configuration, besides being examined in the light of productivity, must also consider the rock mechanics implications at depth. Mining methods must anticipate and prepare for extremely hostile conditions due to seis- micity and virgin rock temperatures.

Jan 1, 1986

Mining companies around the world are seeking methods to coordinate operations between the mine and the concentrator to achieve an overall improvement in enterprise performance. In several instances very significant increases in productivity (more than 20 per cent) and profitability (more than $US 10M per annum) have resulted from such efforts. The key to realising these large benefits has for the most part arisen from improved communication between mining operations and plant operations personnel and the judicious use of new tools to evaluate alternatives for improvement and to minimise the risk of implementation. This paper presents a systematic approach to mine-to-mill optimisation . The importance of systemic thinking and systems optimisation methodologies is emphasised. New tools for evaluating operational performance are discussed. Recently reported benefits are summarised. Finally current research is discussed and projections for the future are given.

Jan 1, 2000

Although the last decade has seen the growth of many new licencing and approval requirements for the exploration and mining industries, there remains in each State of Australia and the Northern Territory a predominant "Mining Act" containing provisions for the grant of exploration and mining tenements. What then are the rights and duties of tenement holders either by virtue of a Mining Act or through other approval and licencing mechanisms? What rights and duties does a person acquire when he is granted an exploration licence or a mining lease? In this paper I will attempt to cover these types of questions using in particular examples from New South Wales. I will also refer to a range of other subordinate approvals and licences which today's society requires and the need for ethics and recognition of liabilities.

Jan 1, 1995

By C. P. BATES

In November 1969, New Zealand Steel Ltd pioneered the commercial use of the SL/RN solid fuel direct reduction process to make sponge iron as a feed material for electric arc furnaces. Serious process problems with the use of green balls and coal injection were progressively overcome. The process was developed by New Zealand Steel along a radical route, of feeding the fine grained raw ironsand concentrate and coal directly to the kiln. Contemporaneously with this development of direct reduction, steelmaking process innovations were made that enabled the arc furnaces to operate successfully with the high volumes of acid slag.

Jan 1, 1980

By K Sommerville

BHP Billiton’s Area C iron ore operation has been in production since 2003. During 2010, below water table mining in the Marra Mamba formation commenced and dewatered ore has been successfully processed through the plant.The ability to mine below water table material increases reserves. Pits can be dewatered using a combination of ex-pit and in-pit bores. Critically it is important to allow suffi cient lead time to dewater. For Area C, in-pit bores yield the most water which presents challenges in every day operations when mining around bores. Operationally there are steep learning curves in obtaining equipment, training personnel and setting up infrastructure. Core risks include lifting, refuelling and maintaining gensets. The pipework, extraction and re-establishment work can be very manual.The challenges include blasting, mining, stockpiling, processing, water balance and disposal. Maximising up time on bores whilst minimising impacts to blast practices have evolved. Blast practices now align bores to the edge of patterns. Protecting bores have evolved from stemming bores with rock and re-drilling to using gas bags which require no drills. Based on moisture and material properties, mining of dewatered material can be categorised into three groups:1. normal,2. sheeting, and3. sheeting and top loading.Ore can go straight to the plant ore to drying pads where it takes between one and three months to drain.Stock management of these piles is important to ensure efficiency of the plant. Rules have been established for blending wet material to maintain feed capacity and some modifications to plants have been made. Dewatering of pits poses a challenge for water use. Initially turkey’s nests were established to capture water and use for dust suppression. As water abstraction has increased methods of management include using exhausted pits for storage and evaporators. Managed Aquifer recharge and use in potable water are being considered. An over arching coordination of the capacity and use are required.Important elements in dewatering include:• capacity models,• capital,• long to short planning,• day to day coordination, and • water level monitoring and balances. Success in dewatering requires a cross function team working towards a common goal. *This is an abstract only. No paper was provided for this abstract.*

Jul 11, 2011

With more difficult economic conditions and increased competition, the Australian exploration industry is allocating increased resources to developing more effective and efficient exploration technologies. A significant number of new techniques have been developed, and Australian companies are now at the forefront of exploration technology worldwide. These should increase the chances of maintaining Australia's leading position in world mining over the long term.

Jan 1, 1987

By J Ralston, W Skinner, D Fornasiero

The Wark has been conducting collaborative research through the AMIRA International P260 series of projects for over 20 years. This paper reviews specific outcomes of successful technology transfer to flotation plant practice over that time. Moreover, findings of an independent audit of industry users of the research outcomes of the P260 project are reviewed. The key to successful technology transfer is the active engagement of industry personnel at all phases of the technology transfer process. Other research outcomes include the novel application of new measurement tools and methodologies which include, for example, advanced surface analysis techniques. These new tools and methodologies have been pivotal to improving our understanding of factors that limit the flotation separation of minerals at plant scale. Future potential targets for technology transfer to improve flotation plant practice are discussed.

Jan 1, 2009

By Hagarty KA

At the northern margin of New Guinea there is a fundamental problem related to the relative timing of arc- continent collision(s) represented in the Papuan Fold-Belt (PFB) and backarc spreading in the Caroline basins. New fission track dates from basement and sediments within major anticlines of the PFB indicate that uplift occurred at 4.0 ¦ 0.5 Ma. The timing is consistent with the fold and thrust shortening (more than 100 km) of the PFB which occurred in the Late Miocene/Early Pliocene as evidenced by the deformed Miocene carbonates and Pliocene molasse deposits. However, in northern Papua New Guinea, earlier work has suggested that ophiolite emplacement and associated metamorphism occurred in the late Oligocene/early Miocene.The evidence suggests that the late Miocene/early Pliocene deformation was of considerably greater magnitude than the earlier obduction event. The Caroline Plate lying north of New Guinea has been interpreted as a backarc basin which commenced spreading in the Eocene and ceased spreading in the Late Oligocene (about 28 Ma). The remnant arc presently docked to New Guinea was active in the Eocene and Oligocene and is believed to be the arc related to the formation of the Caroline Plate. The cessation of spreading of the Caroline Plate has previously been interpreted to be due to arc continent collision during the Late Oligocene/Early Miocene, but such a collision is now known not to have occurred. In the Cretaceous and Palaeocene subduction was to the south beneath New Guinea, but "flipped" in the Eocene to give a north-dipping subduction zone far to the north of New Guinea, driving Caroline Plate backarc extension. This backarc basin reached a limiting size at about 28 Ma resulting in the end of subduction. With the continued northward movement of Australia, Mesozoic oceanic crust was obducted southward onto the New Guinea margin in the Late Oligocene/Early Miocene. In the Miocene south-dipping subduction beneath New Guinea commenced until the now extinct Caroline Plate arc collided with New Guinea in the Early Pliocene, causing extensive regional compression and sinistral strike-slip faulting. This new tectonic framework suggests that backarc basins reach a limiting ridge-trench distance of 1000-1500 knm, beyond which "subduction-pull" cannot drive further spreading so subduction and spreading are terminated.

Jan 1, 1987

Solid Energy New Zealand Limited (æSolid EnergyÆ) is a state-owned coal mining company, producing 4.0 Mtpa from a number of opencast and underground mines in the Huntly, West Coast and Southland regions in New Zealand. The company currently exports 2.1 Mtpa of coking coal. Exports are expected to grow strongly over the next five year as the company expands production into new semi-soft and thermal coal reserves. Domestic coal demand is also expected to grow strongly, particularly in the North Island, as the Maui gas field reserves diminish, and thermal coal becomes more important for electricity generation and meeting the energy needs of forest processing and other industries. Solid Energy is expanding and developing its risk management practices across all areas of the business: strategic planning û extensive use of scenario analysis and probabilistic modelling over a 20 year period; investment decisions û development and application of a rigorous six stage æProject Assessment GuidelineÆ process for all new mine developments; geological and geotechnical risk assessment techniques û use of best practice techniques including seismic surveys; financial risk management û a dynamic approach to hedging based on effects based analysis of Cash Flow at Risk analysis against preset risk tolerances; risk financing û the use of a captive insurance subsidiary, and the experiences of a small coal company seeking to obtain insurance cover on a æhardÆ international insurance market; and integrated risk management û the challenges of trying to implement a broad integrated risk management approach across the company, that supports implementation of strategic objectives as well as meeting æcompliance or legislative basedÆ risk management requirements.

Jan 1, 2003

By K Grohs, A Satriawan, S R. Pearce

Martabe gold and silver mine is operated by PT Agincourt Resources (PTAR) and is situated in northern Sumatra and comprises several deposits in steep terrain, and in a tropical climate, that are required to be developed in the optimal sequence for the best possible Net Present Value (NPV) return on the project. In addition, the waste rock from excavations and tailings from processing is a by-product to be scheduled and used for a number of purposes identified as part of life-of-mine planning. These uses include construction of the current integrated tailings storage facility (TSF) as well as future engineering construction and waste disposal projects which includes plans for a program of in-pit backfilling. These plans need to be aligned to ensure the waste rock and tailings can be contained relative to the production rate. Given that the site will have multiple open pit voids upon cessation of mining activities opportunities for integration of in-pit disposal of mine waste have now been assessed with technical studies to review the practicality of the approach with respect to operational challenges and conformance with closure planning requirements. This includes assessment of disposal of waste rock, tailings (including consideration of filtered tailings) and co-disposal of waste rock and filtered tailings.

Aug 2, 2023

BHP BillitonÆs Yandi channel iron deposit has a large resource of approximately 1.3 billion tonnes. This is a bulk mining operation with a high degree of selectivity not being practical. In contrast the deposit geology is a complex interrelationship of primary channel facies, secondary enrichment of iron and a secondary redistribution of the major contaminants. These variations in geology and alteration can occur over ranges of hundreds of metres down to knife edge contacts. In addition, differences in primary facies and mobility during alteration often result in the iron and contaminants having different patterns of enrichment and depletion. Despite the scale of these operations, if the geological domaining is not optimal, significant errors in the resource estimate of grades and tonnage will occur. Getting the geology right has become a common clichT among mining professionals. However, in many situations, obtaining optimal geological domains for resource modelling is best achieved when there is input from geology, statistics and geostatistics. In this paper, moving window statistics are utilised to see through locally high variability to identify trends that assist in locating difficult to identify geological boundaries. After the creation of geological domains, univariate and multivariate statistics and principal component analysis assist in validating and characterising geological domains. Finally, variography and domain contact analysis are used to analyse the nature of the boundaries between geological domains. At the Yandi channel iron deposit, the inter-relationship between geological and geostatistical analysis has resulted in significant improvements to geological domaining and the treatment of domain boundaries during estimation of iron and contaminates.

Jan 1, 2005