Search Documents

By Anievas JB, Sevillano AC

This paper describes the acquisition, exploration, development, initial operation and subsequent financing of the Bulawan mine by means of a listing on the Toronto Stock Exchange of a subsidiary of the parent company, Philex Mining Corporation.Located on the island of Negros in the Philippines the property is unique on at least two counts: it is a disseminated gold deposit that occurs in a region of predominantly porphyry copper mineralisation; and it is a gold deposit that is mined by a bulk method of extraction (front and block cave) instead of the normal selective mining methods.

Jan 1, 1997

By P A. Jenkins, I W. O Jones

WMC has mined the Perseverance disseminated orebody exclusively by SLC (sublevel cave) methods. Deteriorating ground conditions in the vicinity of an orebody inflection forced a re-evaluation of future mining at Perseverance and a strategy to drop down below the inflection zone and recommence the cave was implemented. This strategy has led to increased production at higher grades, resulting in lower costs and better mill recoveries. This paper describes the evolution of mine planning, development, support and production strategies through the successful process of implementing the ædrop-downÆ and re-establishing the SLC.

Jan 1, 2000

By Cocker A

Pre-splitting for smooth highwall formation is conducted in around 75 per cent of surface coal operations within Australia. The CMTE (Centre for Mining Technology and Equipment) in conjunction with BHPAC (BHP Australia Coal) initiated a project to look at pre-splitting and to investigate the notching of blastholes for fracture plane control. The notching was specifically for pre-split initiation and also for discing of the toe of the production holes to minimise coal loss from the top of the coal seam. There are currently a number of factors which are driving the introduction of new pre-splitting technologies and products. The first is the ever increasing bench height being employed in strip mines which require a higher quality wall with less blast damage to maintain stability. Currently depths of 55 metres are common place with depths of 70 - 80 metres fast approaching. The second factor is the introduction of new technologies or methods which require a high quality highwall produced, eg highwall mining. This paper discusses the current state-of-the-art in pre-splitting and the main issues facing successful pre-splitting in the future. The use of a blasthole notching technology to promote fracturing along the pre-split line is also analysed. The review indicates that most pre-splitting challenges in the future can be addressed through better use and developments of current drill and blast technology. It is also concluded that a blasthole notching technique may find niche applications in improving final walls within a surface coal mine, especially where a high quality wall is required. The notched blasthole method may also allow pre-splitting in ground conditions and adverse rock structure which currently cannot be pre-split by existing technology.

Jan 1, 1995

Attention is drawn to the largest eruptions with dense rock equivalent (D.R.E.) volumes approx-imating 50 km3. These have been strongly clustered during the last 40 000 years, with 11 recognised in the period 35 000 to 22 000 years ago, and 10 in about the last 9000 years, but none in the period 22 000 to 9000 years ago. With the latest such eruption, at Tambora, only 175 years ago, it is likely that we remain in a period of increased activity. During the last 100 000 years, roughly the period during which modern Homo sapiens has existed as a species, there has only been one eruption an order of magnitude larger (>_ 500 km3 D.R.E.). This took place at Lake Toba, Sumatra, about 75 000 years ago, and is estimated to have deposited ash to a thickness of a centimetre or so in parts of Ethiopia, Somaliland, Saudi Arabia and Iran, and to a thickness of a few millimetres in the eastern Mediterranean. The average interval between global eruptions of this magnitude is probably about 40 000 to 50 000 years. Insufficient work on the Quaternary history of volcanoes has been carried out to suggest where the next such eruption might occur. At Yellowstone, which has been well studied, the average interval between very large explosive eruptions is about 700 000 ¦ 120 000 years.As a prerequisite for magnitude-frequency analysis of eruptions, and hazard and risk impact assessments, it is important to classify past eruptions in a consistent manner. In an attempt to find a universally applicable method to estimate order of magnitude D.R.E. volumes from the distribution of airfall tephra, an empirical correction has been derived for the elongation of tephra dispersal fans due to wind. Dispersion distances for various thicknesses of tephra, recalculated for windless conditions, have been obtained from a study of about 40 tephra isopach maps for which D.R.E. volumes have been calculated, and a range of distances derived, equivalent to D.R.E. volumes from 106 m3

Jan 1, 1990

By M Francoeur

Oct 12, 2022

The Energy Authority of NSW has wide powers and responsibilities conferred by its Act which are pertinent to the State's coal industry and its development into the next century. With respect to coal, the broad objective is to maximise the benefits to NSW and its people derived from the State's coal resources. The initial focus of the Authority's coal-related activities in the late 70's and early 80's was on petroleum substitutes from coal. Research was supported, especially on hydrogenation, and the Authority participated in the Joint Australia/Federal Republic of Germany coal-to-oil feasibility study. It also co-ordinated a State Government initiative to involve the private sector in examining the possible establishment of a synthetic fuels industry based on Hunter Valley coal. With a short-fall in world-wide petroleum supply now seen as less likely for some years, the Authority is looking also at ways of working towards the broad objective in the field of coal utilisation on both domestic and export markets. Areas of interest include possibilities for using washery rejects, means of making NSW coal more competitive as an energy source, use of coal-seam gas and new or special technologies for burning coal. The future is expected to see renewed interest in producing petroleum substitutes, and coal - as the State's major energy resource - is seen as a strong contender as a basis for such an industry. Developments in coal-based power generation are also expected to have an impact, with advanced technologies having a possible place here as well as Overseas.

Jan 1, 1987

By G J. A Dewar

The Australian Corporations Law generally requires Independent Expert Reports to be presented in support of capital raising or in defence of mergers and takeovers. The introduction of the VALMIN Code in 1995 (and its recent revision issued as the VALMIN Code, 1998) made Assessment and Valuation Reports in these circumstances much more comprehensible than before because of its key requirements for transparency and materiality. By forcing the Independent Valuer to provide an explanation of the reasoning behind the estimation of a particular resource asset, VALMIN allows the reader to clearly see any error or illogicality in the valuation methodology used and to seriously question or even reject the resulting value. Even though many elements of resource asset valuation practice are undeniably subjective, there must be some basis of objective rationality to it. Independent resource asset Valuers are the essential link between mineral explorers/miners on the one hand and brokers/analysts/fund managers/investors on the other. The minerals and financial industries both expect them to not use inappropriate or invalid valuation methods and illogical steps within these methods. This paper examines some of the less sensible ways in which some of the main techniques that Valuers commonly use to assess the fair market value of mineral properties have been applied in recent instances. The authors hope to discourage the adoption or perpetration of the æWhat-number-did-you-have-in-mind?' approach. It is MINVALÆs view that as many methods as possible should be used in any resource asset valuation. If any of the resulting estimates are in approximate agreement (particularly if they were derived using the less subjective of the available methods), ie if they cluster, they are probably more persuasive as being the Preferred Value of the asset than outlier values within the Valuation Range.

Jan 1, 1999

Intrusion related Cu/Au mineralisation is localised in Pacific Rim island arcs by arc parallel, termed accretionary structures; or arc normal, termed transfer structures. In Papua New Guinea, NE trending transfer structures, evident on Landsat imagery, represent deep crustal fractures which have facilitated dextral rotation of the mainland during oblique plate collision. Major structures localise intrusion centres, and by rotation, develop ore hosting dilational environ-ments in subsidiary structures. While transfer structures localise the Porgera, Wafi and Yandera porphyry centres, the Frieda Porphyry and associated Nena high sulphidation Cu/Au mineralisation are localised by accretionary structures. The Bulolo Graben, which hosts the Morobe Goldfield, developed during intra arc rifting aided by movement on transfer structures. Crustal thinning has initiated magmatism with which diatreme breccias and fracture controlled mineralisation are associated.

Jan 1, 1994

By Marshall K. I

THE problem of satisfactorily eliminating the fumes and dust which are unavoidably produced in various metallurgical and manufacturing industries is one which has received considerable attention in the past, and has been the subject of much investigation and research. The solution of this problem was urgently desired for two reasons, the principal one being the fact that a considerable percentage of the total process losses in many industries was represented by the commercial values of the fumes and dust that escaped from the stack.The other reason is that, in some instances, the emission of the matter is regarded as objectionable. Various methods have been designed with a view to solving the problem thus presented, and the latest development that has beendesigned is the process of electrostatic precipitation. Continued investigational and developmental work with this process has already demonstrated its applicability to many industries, and new uses to which the process can be put are being opened up. Its use is already widespread, and the economic success that has attended its application in most instances would indicate that its use will become more general in the future.It has proved its ability to treat gases over wide ranges of temperature, and has successfully handled various types of fumes whose chemical characteristics differ very considerably. In many processes it has now come to be regarded as standard equipment.HISTORY OF ELECTRICAL PRECIPITATIONThe first recorded observations on the influence of an electrified insulated wire on gases containing solid particles in suspension was made as early as 1824 by Hohlfeld, in Leipzig. He found that, if he electrified a wire hung in a bottle filled with smoke, the smoke cleared rapidly, and a deposit formed on the sides and bottom of the bottle.

Jan 1, 1923

By T M. Brettell, D Sidea

The CSA Mine is located in Cobar, New South Wales and is operated by Glencore. Large scale underground production started from 1965, with zinc, lead, silver and copper extracted in the past. The current operations focus on copper, with a silver co-product.From 2014 to 2016, Cobar Management Pty Ltd (CMPL) undertook a major capital project to upgrade the primary ventilation system at the CSA Mine. This involved the development of ten raises using full-face raise boring from surface to a depth of 1450 m. The total length of the raises was approximately 2500 m. Geotechnical conditions were identified as a key project risk during the early planning stages of the project. Timely quantification of the geotechnical risks was required to minimise project delays and cost overruns. Geotechnical investigations were planned and conducted for each raise prior to pilot drilling and full-face back reaming.Nine of the ten raises had final wall camera and laser baseline surveys completed following full-face reaming. The surveys were conducted progressively, allowing ongoing back analysis and calibration of geotechnical evaluations as the project advanced.This paper presents the design and planning process of the raise bored excavations. It details the geotechnical investigation work undertaken to mitigate the geotechnical risks and the challenges and learnings from the project including the benefits of close collaboration between the parties involved.CITATION:Sidea, D and Brettell, T M, 2017. The CSA ventilation upgrade – geotechnical challenges and learnings, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 341–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Cotton R. E, Cox R

Digger Rocks is one of several nickel-bearing sulphide deposits localised within komaLiitic volcanics of the Forrestania Greenstone Bell within the Archaean YiIgam Block of Western Australia. Exploration and evaluation to April 1990 have delineated a resource, at a nominal cut-off grade of 0.5 per cent Ni, of 1.9 Mt at 1.1 per cent Ni within a lensoid sulphide body which strikes NW, dips 50°SW, and occurs at a depth of 30 - 110 m below surface. There has been no production from any of the Forrestania nickel deposits to-date. The deposit, comprising both disseminated and massive sulphides, has maximum dimensions of 400 m strike, 115 m vertically and 90 m true width. Generally the massive sulphides occur at the base of the disseminated sulphides, on or close to the base of the Digger Rocks dunite. The two main massive sulphide lenses have maximum dimensions of 120 m strike, 75 m vertically and 16 m true width (northern lens) and 60 m strike, 25 m vertically and 4 m true width (southern lens). The average grades of the massive and disseminated sulphides are 5.9 per cent i and 1.2 per cent i respectively. The massive sulphides generally have sharp hangingwall and fOOlwall contacts and display strong internal grade anisolropy.The massive sulphides are mainly within the supergene zone and consist of violarite, pyrite and marcasite. The disseminated sulphides are mainly within the primary zone and consist of pentlandite, pyrrholite, pyrite and minor chalcopyrite. Alteration zones, up to six in number, are complex in detail. The sulphides are capped by an average of 30 m of sub-economic, leached, siliceous, oxidised material.A genetic model for the deposit is described which places Digger Rocks in Category 2 (sulphides in large layered dunite bodies) of the latest classification of komatiitic nickel sulphide deposits in the Yilgam Block of Western Australia by Hill and Gole (1990).

Jan 1, 1992

By L Neindorf

The development and application of paste fill, cement slurry aggregate fill and shotcrete bulkheads at Mount Isa Mines is described. The progressive changes in filling style in the Mount Isa copper mines from a dry fill based cemented rock fill to tailings based paste fill and slurry fills is explained. The development of shotcrete arched bulkheads and engineered drainage system is described. Details on how Mount Isa Mines has achieved approximately 30 per cent cost reduction in backfill operations through innovations are given. The development of a rocky paste fill is explained.

Jan 1, 2005

By D Kepert, C Simpson, D Edwards

Channel iron deposits (CID) currently supply over 40 per cent of the seaborne iron ore trade out of the Hamersley Province. The two well documented producing systems (Robe and Marillana palaeochannels) were both discovered during early reconnaissance mapping principally by BHP Billiton (BHPB) and Geological Survey of Western Australia (GSWA) during the mid 1950s to early 1960s. Both crop out extensively over the majority of their length. Hot on the heels of Fortescue Metals Group 2004 - 2005 discovery of approximately 2.6 billion tonnes (Bt) of undercover iron ore mineralisation in the Chichester Range, the Fortescue Exploration Department turned its attention elsewhere throughout the Hamersley Province. Reappraisal and analysis of publicly available data and ground truthing of developing models led to the recognition of the Solomon palaeochannel system. Subsequent exploration defined a world-class Resource of some 1.9 Bt of iron ore mineralisation of which the great majority is buried CID. Apart from the Marillana CID system, the Solomon region is the only major CID with significant tonnes of sub two per cent alumina CID with over 500 Mt delineated to date. Exploration has also outlined significant supergene bedded and detrital iron ore mineralisation. Ongoing drilling is expected to increase the resource base both in terms of tonnes and confidence. This paper outlines the principal contributing factors which led to the discovery of the Solomon CID and compares its geology with the Robe and Marillana palaeochannel systems.

Jan 1, 2009

By Fradd WP

South Australia pioneered metal mining in Australia and was the main source of copper for several decades. Gold discoveries and mining also contributed significantly to the development of the Colony. Across the State can be seen the holes, the mullock heaps and, in some instances, the remnants of machinery of the past era. In this, the centenary year of the discovery of the Teetulpa goldfield, considered by some to he the most significant discovery of gold in the State, it is appropriate that we should present a paper on the history of gold mining in South Australia. South Australia has not been a major producer of gold with recorded production a little in excess of 15 million grams (15 t). This represents about 0.25 per cent of the Australian total and ranks last of the States of the Commonwealth. The outstand- ing feature of gold production in South Australia has been the succession of short periods of rela- tively high production immediately following a discovery, with payable dirt being quickly exhausted, a fact clearly illustrated by the graph of South Australian gold production (Figure 1).

Jan 1, 1987

The carbon-in-pulp (CIP) process is now well established in the South African gold industry, with a total of over I million metric tons of material being treated each month in six large plants. This tonnage is derived from ground ore, from filtered pulp, from calcine, and from reclaimed sand-tailings dumps. With this new process and the new large plants, those concerned with CIP are experiencing a learning process, since each new plant presents a different set of problems to be overcome. The knowledge and experience gained from these plants is being shared, and will be of benefit in the design and operation of new plants. The CIP process can be subdivided into the following unit operations: prescreening at a fine size, adsorption, acid-washing and elution, reactivation, and electrowinning. Results concerning each of these unit operations, which were obtained from pilot plants and from large-scale CIP plants in South Africa, are presented. The latest developments in each of these areas is summarized. Tables that are included as an appendix contain some information concerning the equipment in these new CIP plants plus operating results from some plants.

Jan 1, 1982

By A Parry, C Fitzmaurice

After conducting laboratory ore sorting testwork on samples of a low grade nickel ore stockpile at Western Areas’ Flying Fox nickel mine, a mobile crushing, screening and ore sorting plant was located adjacent to the stockpile. An initial two month trial of the ore sorter program proved successful and was extended to process the entire Flying Fox low grade stockpile in a further four month campaign. A total of 167 660 t of low grade ore was processed, providing highly upgraded feed trucked 26 km to the Cosmic Boy concentrator. A more than three-fold grade increase was achieved on ore sorter accepts. The moderately upgraded fines that by-passed the mobile ore sorter were also subsequently blended into plant feed. This paper describes the mineralogy of the Flying Fox low grade ore, the mobile ore sorting campaign and provides some commentary on the economic and environmental benefits achieved in the ore sorting campaign. The ore sorting campaign demonstrated the benefits of being able to utilise mobile ore sorting equipment temporarily located adjacent to sub-economic low grade stockpiles in order to effectively treat these stockpiles and produce viable plant feed.CITATION:Parry, A and Fitzmaurice, C, 2018. The upgrading of low-grade nickel ore stockpiles at Western Areas Ltd Forrestania operations, using a mobile ore sorting plant, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 541–550 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By D J. Clark, R F. Wright, M D. Goodz

The A1 Gold Mine is a Devonian-age narrow vein high-grade gold deposit located 115 km east of Melbourne. The mine operated almost continuously from 1861 to 1992 producing 442 334 ounces of gold (13.8 t) from 530 436 tonnes from primary gold ore tonnes processed at an average recovered grade of 25.9 g/t Au. The A1 dyke was attributed with a yield exceeding 620 000 ounces (19.3 t) of gold (including gold in alluvial and tailings deposits), and was renowned as one of VictoriaÆs premier mines paying considerable dividends. The orebody was principally in a diorite dyke bulge 150 m long, 45 m wide and 700 m deep and was mined via two vertical shafts. The mine site was closed in 1992 and the site was rehabilitated in 1999. In 2008 - 2009, a diamond drilling program identified various extensions to the host dyke lithology and to gold-bearing quartz vein filled fault zones over a 700 m strike length. The outcome of this study was the establishment of a mine geology corridor four times longer in strike length than the original 1970s model. This opens A1 dyke hosted deposit style to exploration outside the historical dyke bulge and provides exploration opportunity for all similar deposits. Construction of the first 3D geological model has developed new insights on the host rock diorite dyke system and identified various extensions to both host stratigraphy and to gold-bearing mineralised structures. Coarse visible gold in quartz vein mineralisation (>30 g/t Au) and medium-grade stockwork mineralisation (8 - 15 g/t Au) has been intersected within 100 m of the surface and up to 300 m along strike of the nearest historical underground workings. At depth it appears that the mineralisation is continuous with the main dyke body with consideration of minor rotation in the strike orientation and limited reverse thrust faulting showing maximum displacement of 10 - 20 m. Along the A1 mine corridor, between two and five parallel dykes are observed at different drill sections. The gold mineralisation is hosted mainly within the dyke rocks, but where the sedimentary rocks are intensely silicified or are xenolith rafts, the gold mineralisation continues across these sedimentary rock blocks. There has been inference to the role of silicified sedimentary rocks as a second ore host and a bounding material for inflections in fault and vein orientations. In the central 150 m long A1 mine dyke bulge, the extremities are demarcated by four to five parallel dyke fingers (referred to as apophyses) going both north and south. These apophyses are clearly observed both vertically and horizontally between levels No 4 and No 9. The dyke fingers entrap sedimentary rock xenoliths and collectively form the A1 dyke æcorridorÆ, which is quite uniform in overall width from the easternmost contact (footwall) to the westernmost contact (hanging wall). Dyke fingers were assumed to coalesce at depth into a single dyke, but recent drilling shows this feature to repeat in several positions with depth and along strike. Key observations are the relationship between gold grade and fracture density, alteration, sulfidation, host rock morphology û relation of contact shape and fault zones. These relationships allow for the classification of prospectivity indicators and geology as a guide to potential extensions of mineralised zones. Mining geology is contributing to the whole-of-mine life planning and development where decline path, stockpile and infrastructure positions are controlled by geology.

Jan 1, 2009

The Kalgoorlie Golden Mile is proposed as an Archaean volcanogenic-type deposit, modified and redistributed along later-developed structures. Rich pyritctelluride and Green Leader gold mineralization is associated with the end phase of basic volcanism and, in a general sense, is confined to a broad interface zone between the products of marine basic volcanism and later acid volcanism. There is virtualIy no ore associated with the main body of acid volcanics.Green Leader is the local name of a type of ore that occurs at some igneous rock contacts in association with graphitic sediments and layered acidic tuffs. It is characteristicalIy green, of various shades, and commonly yields very high gold assays, the reasons for which are not apparent in hand specimen.Carbonates, carbonaceous shales, tuffites, rich gold ores, and acid and intermediate dykes, alI indicating a common heritage, are features common to the main ore hosts, viz. the Paringa Basalt (Calc Schist) and theGolden Mile Dolerite ("Quartz Dolerite Greenstone").Several probably related fracture systems have reconstituted most, but not all, of the original deposits into a large number of steep tabular lodes.Includes two sets of discussions and comments from later Proceedings volumes.

Jan 1, 1974

By R J. Cuttler

In January 1998 Sydney Water Corporation formed an Alliance with construction contractor Transfield, and engineering consultants Connell Wagner and Montgomery Watson, to design and construct the Northside Storage Tunnel. The project is part of WaterPlan 21, Sydney WaterÆs strategy for cleaning up the harbours, bays, rivers and beaches within its business area. WaterPlan 21 is an integral part of the NSW GovernmentÆs $3.1 billion Waterways Package which establishes targets and initiatives for sustainable wastewater management within NSW. The project is being delivered under an Alliance Agreement, which has a number of non-traditional features in terms of partnering, management principles and design and construct. Construction began in mid-1998 and is on target to meet the completion deadline for the Sydney 2000 Olympics.

Jan 1, 1999

The Cannington silver lead zinc deposit is located near Mt Isa in North West Queensland. This world class orebody is owned by BHP World Minerals (BHP) and is estimated to contain 45 million tonnes of ore at an average grade of 11 per cent lead, four per cent zinc and 500 grams/tonne silver. At BHPÆs planned 1.5 Mtpa extraction rate, the mine life will exceed 20 years. Construction of the underground mine, which commenced in August 1993, was carried out by Peabody Resources Ltd (Mining Services Division) (PRL) for BHP Minerals Pty Limited (BHP) under contract packages totalling approximately $100 M using several innovative techniques to deliver safety, quality and time related project goals. Client/Contractor Partnering, resulting in harmonious working relationships, a combined commitment to the achievement of an excellent safety record, and a seamless transition from the construction phase to operation of the mine, has been a feature of the project.

Jan 1, 1998