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By K Smith

This paper presents an assessment of the Robertson (2010a) method within the CPTu inversion parameter framework of Been et al. (1987), using CPTu calibration chamber data presented by Jefferies and Been (2015) and in other literature to assess the validity of the method, with particular focus on applicability of the method to TSFs (i.e. its applicability to loose silts and silty sands). The assessment demonstrates that although the method estimates values of k consistent with calibration chamber data, the method estimates values of m that are generally 1.5 to 2 times greater than calibration chamber data. As a result of this, the method generally overestimates Ψ for values of Ψ less than 0, and underestimates Ψ for values of Ψ greater than 0. This may result in both overly conservative assessment of materials as potentially liquefiable and unconservative predictions of material behaviour for loose materials.

Jul 1, 2021

In the UK during the 1990s the energy companies had developed a policy of æDash for GasÆ, building large natural gas power stations to produce more than 30 per cent of the UKÆs electricity demand. The price of imported thermal coal was dropping and the electricity generators were putting pressure on the UK coal producers to produce coal at a reduced cost. Imported coal from Columbia, South Africa, America and Australasia had increased their market share in thermal coal sales to over 50 per cent of a 55 Mtpa market. The pressure on the UK coal industry to reduce costs and improve productivity levels from an ever decreasing resource was high. Companies were benchmarking their operations on the imported coal producers and had to realign their organisations, productivity levels and costs to world best practice, not just technically, but in world class organisational management techniques.

Jan 1, 2005

By J P. Evert

Didipio gold-copper mine operation is situated in the island of Luzon, approximately 270 km north of Manila in the Philippines, in an area of high seasonal rainfall. The hydrogeological water flow model implied that there would be high connectivity between regional structures and underground operations. This model predicted that underground mine groundwater inflows were expected to quickly rise as the decline progressed to a peak of 510 L/s. Designing a capital pump station to deal with 510 L/s has its own challenges, however developing the decline down to the required level, always dealing with 300 L/s of water and constructing the pump station is extremely challenging and required a robust water management plan and mine design. When dealing with expected high volumes of water, underground mine design and scheduling plays a key role in protecting electrical infrastructure, equipment, secondary pumps, and the decline from flooding. A good drainage system and controlled dewatering plan is essential for safety and progress. This paper details the dewatering techniques and mine designs required to accomplish decline development with high water inflows as used in the Didipio project. It will describe the learnings and outcomes that are achievable with a flexible design, as new structures are mapped, and water intersections are increased. It also highlights the potential for adaptability in mine planning to provide evolving improvements or to evade problems that are expected from the constant reconciliation of data recorded during development.

Mar 29, 2023

By Laxaminarayan Holla

Significant coal reserves in New South Wales lie underneath major bodies of natural and stored surface waters. In order that mining can occur safely and without any adverse effect on the surface, various statutory provisions and administrative guidelines have been framed for regulating the surface and sub-surface strata disturbance. There are particular bases for the existing guidelines and the assumptions which were made in their choice. Evaluation of the guidelines in the light of the knowledge gained during the last ten years indicates that they are conservative in some cases and can be made less restrictive without lowering the safety standards. The suggested changes include reduced width for pillars in both bord and pillar first workings and panel and pillar workings, and increased level of extraction for a given degree of subsidence. Changes, if implemented, would lead to increased coal recovery.

Jan 1, 1987

Breakwater Resources Ltd is a Canadian base metals producer with Cu-Pb-Zn operations in Canada, Honduras, and Chile. Two of its operations contain economical gold levels which are recovered in both gravity and flotation concentrates. The gold payable terms in zinc concentrate are poor when compared to gold concentrates or copper concentrates and various flow sheets have been evaluated by Breakwater staff to maximise gold reporting in higher value products. The Myra Falls mine in British Columbia recovers coarse gold in the grinding circuit, part of which is upgraded and sold as a gravity-gold concentrate with the balance being directed to the copper concentrate. A sampling survey showed that there was potential gravity-recoverable gold in the copper regrind circuit. Installing a gravity concentrator in the copper regrind circuit increased the gold grade and recovery in the higher revenue copper concentrate and reduced the quantity reporting to the less well paid zinc concentrate. The El Toqui Mine in southern Chile has distinct high-and low-gold orebodies which are campaigned separately through the flotation plant. The high gold zone yields both a gravity concentrate and an unusual gold flotation concentrate. The gravity concentrate undergoes intensive cyanidation and electrowinning on-site to produce dore, while the fl otation concentrate is sold to gold producers. The zinc concentrate contains signifi cant gold values. The paper describes efforts over the past few years to improve gold returns at Breakwater's operations and highlights the different approaches dictated by the mineralogy of the gold occurrences at these two operations.

Aug 1, 2010

By W Patton, I Minniakhmetov, H Talebi, U Mueller

The sustainability of mining projects is linked to informed investment decisions based on public reporting of exploration and mineral resource estimation results. In Australia, public reporting guidelines are established by the Joint Ore Reserves Committee reporting code through the JORC Code (2012). Although the assessment of uncertainty in the results reported is a requirement, this is often communicated qualitatively and evaluated subjectively. This can become a liability particularly in the early stages of mining projects when spatial domains of geological interpretation and mineralisation envelopes inform resource estimations’ reliability. A recent review of JORC reports found no reports used quantitative assessments of the geological interpretation or mineral resource estimation envelopes, and 27 per cent of reports did not address the question of quality of geological interpretation. Reports that did address the quality used 19 different terms to communicate quality. This work presents methodologies for quantitative uncertainty assessment and communication and explores how they could be applied in public reporting practice. Quantitative uncertainty reporting would benefit mine planning and financial modelling as they normally assume the geology is 100 per cent right (since no error is reported or only a single deterministic model is provided). The complexity, cost, and additional work of doing a quantitative assessment could hinder a straightforward implementation. This could be overcome if mining companies budget for quantitative uncertainty assessment and associated professional development. A compulsory requirement for the inclusion of uncertainty assessments in public reporting or adopting standardised subjective language would improve industry practice.

Mar 22, 2022

By S Hawker, M Gibbs, A Craven

Current climate change projections suggest both an increase in the intensity of significant rainfall events and an increase in the variability of rainfall in some regions of Australia. It is necessary for mine site owners and operators to understand the effects that this potential shift in climate may have on their operations. The ability to maintain compliance with discharge regulations and operational security for those sites that rely on surface water run-off harvesting may be negatively impacted if some current climate change projections are realised. Although current regulations require the preparation of water management plans, these are generally developed using historical climate records for the site in question and as such do not give any indication of a siteÆs resilience to the influences of climate change.This study compares design and operational considerations for a case study mine site using historical rainfall records and modified records representing climate change projections. The future climate models are invariably broad scale and are limited in their capacity to be downscaled to a reasonable resolution for developing a site water balance. Instead the local historical data set has been modified to concentrate precipitation to peak periods and propagated through the model. The study looks at the siteÆs response to the potential changes in climate.It is shown that if current climate change projections are realised, this will have a significant effect on both the necessary size of designed surface water infrastructure and operational considerations on-site. A discussion is presented on the potential risks that climate change presents to mine sites and the range of options that could be considered to mitigate these risks. Depending on a number of factors, including location and risk profile of the owner/operator, resilience to climate change can be addressed as either a capital or operational expenditure (CAPEX/OPEX).CITATION:Craven, A, Hawker, S and Gibbs, M, 2013. Site water balance response to variable climatic conditions, in Proceedings Water in Mining 2013 , pp 211-216 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

The discovery since 1990 of four major orebodies in the Mt Isa Inlier - Century Zn-Pb, Osborne Cu-Au, Cannington Pb-Zn and Ernest Henry Cu-Au - only serves to enhance the already high stature of the Inlier in world mining importance. Currently the known mineral resources of the Inlier represent about 11 per cent of the world's Pb-Zn resources, five per cent of the world's Ag resources, and one per cent of the world's Cu resources. More can be expected to be added to these impressive figures given that two-thirds of the Inlier remains obscured by younger cover. Individually, projects such as Century and Cannington may ultimately achieve `world's best' status; Century's proposed production of 450 000 tpa of Zn metal would rank it close to number one with Cominco's expanded Red Dog project in Alaska. Cannington, with projected production of 660 tpa Ag, could become the world's biggest producer of silver. For comparison, Mt Isa produced 170 000 t of zinc metal and 335 t of silver in 1995. The apparent physical diversity of deposits in the Mt Isa Inlier is matched by a great diversity of opinion as to their origins. Because Ernest Henry is hosted by `porphyries', it is described by some as a porphyry copper deposit, despite mineralisation age possibly post-dating volcanic age by 200 Ma. Cannington Pb-Zn could be a Broken Hill-type (BHT) exhalitive deposit, or a late epigenetic replacement `regional skarn'. Mt Isa - Hilton Pb-Zn deposits appear to have experienced all deformational events and he syn-diagenetic in origin, or may have experienced little of the above and be epigenetic replacement deposits formed late in the major Isan orogeny, some 150 Ma after deposition.

Jan 1, 1996

By D J Williams

Coal washery wastes comprise tailings, finer than 0.5 to 0.1 inn depending on the sophistication of the washery, and coarse reject, typically finer than 50 mm. Subaerial disposal of coal tailings slurry at about 30 per cent solids by mass results in the formation of a delta with an average slope of about 1 in 100, representing one extreme. The ravelling of coarse reject on loose-dumping, results in an angle of repose slope with an angle of about 37" (1 in 1.3), representing the other extreme. The pumped co-disposal of coal tailings and coarse reject results in the formation of an upper delta with an average slope of about to one in ten, between the two extremes. The depositional behaviour of these three waste streams is discussed and compared in this paper. The important depositional and material parameters, and a theoretical description of the processes involved, are also presented. Comparisons are made between the depositional behaviour of the various coal washery waste streams, and natural depositional systems, such as rivers, alluvial fans, and scree slopes.

Jan 1, 1998

Our ultimate resources come from the Sun and the Earth System. At this time we face a world crisis in energy, water and soil resources. Global pollution problems are increasing in almost all nations. There is an urgent need to use our vast knowledge with a new wisdom and this requires new integrated teams of experts to provide the best alternatives for the needed new development problems. These teams must include economists, engineers and a broad spectrum of scientists. Today it is possible to produce clean energy, stop soil erosion, clean water and reduce and use wastes of many types.

Jan 1, 1995

By Falbo A, Quarestima S, Cozza C, Barbaro M

A new synthetic reagent of the mercaptobenzoxazole class, 5- methyl-2-mercaptobenzoxazole, has been studied. This reagent exhibits powerful selective collecting action towards copper sulphides present in several complex ores, as demonstrated both by laboratory and pilot plant tests. Industrial production is expected to start in the near future. The way this reagent reacts with pure chalcocite has been studied utilising in situ FTIR techniques, adsorption tests, electrokinetic potential measurements and Hallimond cell flotation tests. The FTIR studies have indicated the nature of the surface phase. Adsorption isotherms obtained by the rest method have revealed the quantitative evolution of surface products, permitting the determination of surface coverage at various reagent concentrations. The electrokinetic potential has been utilised to verify the stability of individual species in diverse concentration ranges. Correlation of the results obtained has provided indications on the chemical interaction of this reagent with the surface and on the surface Arrangement.

Jan 1, 1993

By G M. Mudd

The growing popularity of platinum and platinum group metals (or PGMs, including palladium, rhodium and others) for a wide range of applications leads to some interesting issues for mining and sustainability. The uses for PGMs includes catalytic converters for air pollution control in vehicles, growing jewellery use, catalysts for various purposes (especially petroleum and chemicals processing), hydrogen fuel cells and many others. Given the growing importance of most of these PGM uses in more sustainable technologies or in making industrial processes more efficient, it is critical to understand the complex sustainability issues which surround platinum and PGMs. At present, South Africa is the dominant PGMs producer and holds about 88 per cent of estimated global resources, with important but relatively minor production and resources in Zimbabwe, Russia, Canada and the United States. Given the concentrated location of PGM resources, what are the likely trends in PGM mining with respect to environmental sustainability? That is, what are the costs in terms of energy, pollution, greenhouse gas emissions, water, land use impacts, social impacts, economic aspects associated with this globally important industry? This paper compiles and analyses a range of data on platinum-PGM mining, focusing primarily on South Africa. It synthesises a unique combination of data which relates typical production aspects such as ore grade and scale with sustainability aspects such as greenhouse, energy and water costs. The findings are critical in understanding the debate about the increasing environmental and social costs of some materials and technologies which are considered crucial for sustainable industries based on PGMs. Overall, the paper represents a valuable insight into the platinum-PGM sector, providing a range of useful data for understanding the environmental sustainability of this particular group of precious metals.

Jan 1, 2009

The Skybolt is a new bolt concept, point anchored with resin in large diameter holes of specific sizes 38 mm and 45 mm. The new design achieves the optimum annular spacing required for mixing the resin anchor components which is essential for optimum resin bonding of the bolt to the surrounding rock. This paper explains the load transfer mechanisms between bolt/resin/rock, unique to this bolt concept. It compares the pull-out test results to those of paddle and expansion shell type bolts, and highlights the versatility of Skybolt over existing, currently used, rock support systems and the benefits mine operators can achieve when using the Skybolt.

Jan 1, 1992

By B Broad

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

Jul 1, 2013

By R P. Varden

This paper looks at the design of the Bentayga raisebore with subsequent back analysis using a LiDAR survey. A search for LiDAR raisebore assessment publications shows little work has been done on this subject. The paper examines the empirical design and RS2 modelling assessment with the bored condition. The high resolution of the LiDAR enabled mapping of weak structures that were located on the geotechnical investigation hole the orientations of which could not be determined. In addition, the scan showed were water ingress was occurring, potential stress overbreak and structural controls on stability. The LiDAR results were able to confirm no additional support work such as a shotcrete liner is necessary. The LiDAR results have been analysed in one metre increments as volume of overbreak against the empirical stability criteria (McCracken & Stacey 1989). The future use of LiDAR mapping over a range of rock mass conditions will provide quantification of the established empirical assessment improving its reliability. It is also a useful and accurate tool to monitor long term stability of a raisebore due to stress change or ore pass due to wear.

Mar 15, 2021

This paper examines the cost and economic consequences of varying a number of key factors in the course of developing and operating new underground longwall coal mines with both shallow and deep cover in New South Wales. The economics of the project are assessed for the first 20 years of mine life using the discounted cash flow method with produc- tion and selling price being determined to provide break even costs for a range of minimum rates of return.

Jan 1, 1988

By L Muñoz, L Steffen, W Vilas Boas, G Gontijo, R Macedo, C Braga, d D Machado, G Stevenson

Mines operating close to communities face growing challenges, especially with their drilling and blasting activities. Proper management of environmental and community impacts is critical to provide sustainability to the mining business in the long-term, by enabling the licensee to operate. This paper will present new technology solutions to minimise the impacts to communities and the environment from blasting operations. A case study of the wireless initiation projects conducted at Kinross Morro do Ouro Mine (located in Paracatu, Minas Gerais – Brazil), will be presented. Focused on overcoming the complex challenges in the mine, Orica and Kinross searched for initiatives to optimise the drilling and blasting operations. The team evaluated the WebGen™ wireless initiation system for controlling environmental impacts as well as operational flexibility and productivity. Since January 2023, three planned wireless blasts to demonstrate the technology and applications were executed. In the tests, the vibration level was able to be maintained lower than the limit of 3.0 mm/s while dust and flyrock impacts were well controlled. The main benefits of using this technology for the Morro do Ouro Mine are: reducing the number of blasts while increasing the blasted mass per month; control of projection of fragments using additional cover; dust control by watering the bench easily; lightning initiation risk reduction due to the absence of wires or tubes on the surface; flexibility in changing the blast day to better control the noise and dust; flexibility in mine planning mining (potential application in the future). The use of the WebGen™ wireless initiation system, enables improved productivity while enhancing safety and reducing impacts to communities. Implementation of this technology has enabled Kinross Morro do Ouro Mine to build trust with its neighbours, maintain the license to operate, and helping to mobilise resources in a sustainable way. This has allowed Kinross to position Morro do Ouro Mine as a world reference operation, especially in relation to innovation, safety, and social responsibility.

Sep 1, 2024

By Aitchison J, Clarke G

A reappraisal of the stratigraphy, new regional kinematic analysis and thermobarometric data allow a new interpretation of the metamorphic zoning and tectonic structure of the Upper Eocene high-pressure metamorphic core complex of northern New Caledonia allow a three steps evolution to be proposed : 1) subduction and understacking of previously thinned continental crust elements; 2) subduction blocking due to the crustal thickening; 3) crustal thinning and extensional detachment during the diapir-like uplift and unroofing of the eclogitic core. Steps 2 and 3 may be partly contemporaneous. Such a model accounts for the thermobarometric and radiochronologic data, and also for the weakness of substratum deformation during the emplacement of the ophiolitic nappe.

Jan 1, 1995

By OÆShea P. J, Dickson T. W

In April 1994 the Victorian Premier announced new State initiatives, collectively termed the Victorian Initiative for Minerals and Petroleum (VIMP), for exploration totalling $16.5 m over three years. The program, initially centred on the northwest of Victoria, the Eastern Highlands and the Otway Basin, is due for completion in June 1997 and has been designed to attract explorers to highly prospective but currently under-explored parts of the State. Major components of the program include acquisition of geophysical data (including airborne magnetics and radiometrics, gravity and seismic data), stratigraphic drilling, geological mapping and mineral resource data compilation. At the completion of the current program, 70 per cent of the State will have been covered by airborne magnetic and radiometric coverage at 400 m line spacing or better (Figure I) while 20 per cent of the State will have been covered by new geological mapping. The completion of database compilations for geochemistry, mine data and exploration licence summaries during the VIMP program is shown in Figure 2. The new airborne geophysical surveys have been flown partly under the VIMP program and partly by AGSO under the National Geoscience Mapping Accord (NGMA). Data from these surveys have been interpreted and incorporated into the geological mapping in order to enhance the quality of map products, especially in areas of Cainozoic cover. The first series 1:250 000 scale geological map coverage of Victoria was completed by the Geological Survey of Victoria (GSV) in 1977, and was based on compilation of historical geological mapping with minor field checking in most cases. The first metric 1:50 000 scale geology maps were also commenced in the 1970s, but were discontinued in the 1980s in favour of 1:100 000 scale map production. Driven by customer survey findings and with the benefit of detailed airborne geophysical data in the 1990s, the GSV reverted to 1:50 000 scale map production in 1995, with 1:10 000 scale maps made in areas of significant gold production. Geological reports still cover standard 1:100 000 scale map areas, but are now accompanied by four 1:50 000 scale maps. These new series 1:50 000 scale geological maps have been supported by comprehensive mine data and exploration licence summary databases in addition to the new geophysics, and benefit from the advances made in structural geological interpretation over the last decade. The new phase of geological mapping in Victoria, commenced under the NGMA in 1990 and accelerated under VIMP in 1994, has been focused in the central Victorian goldfields and eastern Highlands areas of the State (Figure 1). Results to-date have led to a number of major advances in the understanding of the eeoloeical evolution of Victoria.

Jan 1, 1997

By B Belle

"Mines around the world are inherently and operationally diverse. Current methodologies for the design of mine ventilation and cooling infrastructure involve controlling major safety and health hazards. Globally, it can be estimated that mine ventilation systems from various commoditiescirculate over 150 000 m3/s of exhaust air through shafts. Additionally, over 2 000 000 workersare transported every day through shafts in labour-intensive mining countries like China, India,Southern Africa, and the Americas. A key objective of this paper is to share experiences and provide a case for the revision of ætime-honouredÆ ventilation design parameters based on a benchmarking exercise on design exhaust shaft velocity from various global operations (gold, diamond, platinum, coal and base metals). An active fi eld observation on exhaust shaft velocity has indicated that, regardless of the commodity or continent where the mine operates, almost all life-of-mine (LOM) design parameters provided are in the same range of 20 m/s to 22 m/s, which is not convincing considering signifi cant variations exist in shaft depths, geography, commodity, operating and capital costs. From a due diligence perspective, there are no documented views that are available on the most widely used design exhaust air velocity. Based on the global exhaust shaft velocity data, it is noted that a significant portion of shaft velocities are outside the current design velocity of 20 m/s (some operating up to 30 m/s) and other signifi cant portions of the exhaust shafts operate in the critical velocity range. In the case of Australian coal mines, limited data suggests that none of the mines have ever reached the LOM design exhaust shaft velocity. It is self-evident that when the shafts are not operating at their design quantities either the mine system resistance is low or the ventilation and main fan is operating ineffi ciently. The most common reasons given for not reviewing the shaft system were, ætime-honouredÆ design parameter are being used and cannot be changed, mine fan pressure limits, possible fan blade damage, possible spontaneous combustion risks, leakage or simply did not consider such a possibility. In conclusion, the study has reiterated the historic lessons that a safe and expensive airway should not be utilised uneconomically by circulating too litt le air through it."

Jun 1, 2012