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By Sehic O. A

Geology can be the root of evil or a source of bliss; there is a choice; to ignore geology is at a mine's peril.Risk can be minimised and profitability maximised by the application of a detailed understanding of geology, alteration, structure, mineralogy, chemistry, fabric and texture.Geology is dynamic, not static.The impact of geology is pervasive.The integration of ore quality control with grade control is one strategy for improving the utilisation of both the mineable reserves and existing plant and equipment. Grade maintenance is but one constraint on the problem of how best to blend the ore. Other ore characteristics such as mineralogy, hardness for grinding, and pulp fluidity or density for slurry size classification can be included to explore alternative blending Strategies.

Jan 1, 1993

By C Hawtin, B Miller, D Ashton

Ernest Henry mine (EHM) is an Iron oxide copper-gold sublevel cave mine located 30 minutes north of Cloncurry in North-West Queensland. The underground mine lies beneath open pit excavations, which were in operation from 1999 to 2011. Fault structures carry large quantities of water from the cover sequence aquifer into the underground mine area. The open cut excavations exacerbates vulnerability of the underground mine to the high intensity wet season storms of northern Queensland. These factors combine to make hydrogeological issues high priority for mine operation. Water-related risks include the cost of removing water from the mine, flooding risk and mud rush potential.Turnover of key technical staff in late 2015 at EHM resulted in the mine being left in an untenable position of losing the primary source of technical knowledge. Due to encouragement of cross-disciplinary activity coupled with workload and resource sharing, the management team were confident in utilising on-site personnel to offset loss of experienced personnel.Remaining geology personnel took additional responsibility for hydrogeological monitoring equipment and planning of upcoming work. Consultant input was limited to review only and an emphasis was placed on knowledge transfer to the geology team. Using this strategy, a 13 hole dewatering program was successfully implemented, achieving a significant water level drop in areas of elevated hydrological risk, whilst also upgrading the hydrological monitoring sensor array.Through a development program centred on cross-disciplinary exposure, the technical team was able to retain key technical knowledge despite staff turnover and produce strong results outside traditional training and roles. This paper serves as a case study on the methods, strengths and drawbacks of putting a focus on cross-disciplinary exposure as a method to combat staff turnover.CITATION:Ashton, D, Miller, B and Hawtin, C, 2017. Go with the flow – managing hydrogeological staff turnover at Ernest Henry mine, in Proceedings Tenth International Mining Geology Conference 2017, pp 129–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

In blasting large tonnages of ore or material, the economy of the operation 'depends mainly on the mine manager's judgment in placing the holes to the best possible advantage and in determining the most effective size of hole to suit the conditions and requirements.The placing of holes is often looked upon as a problem involving so many uncertain factors that the application of simple mathematics is impossible. The uncertain factors arise when dealing with strata of different character, in hardness toughness and resistance to shearing.A study of the practice at many mines where all types of strata from hard ore to relatively soft overburden, and even coal, is being mined, suggests that the problem is not as complex as generally believed. There is, without doubt, some uniformity in the amount of burden given to holes of equivalent dimensions, regardless of the material being mined. The reason is simple. With too great a burden hard rock will not break out and soft rock will "bull". The nature of the strata is taken care of by the strength, quantity and distribution of the explosive charge and, to some extent, the spacing of the holes.It is because burdens are uniform in all classes of strata met with in mining, that a formula can be used to design blast hole layouts.The formula introduced in this paper is empirical as it is based on prevailing practice. It has been tested and proved remarkably accurate against every example available to the writer. Many thousands of blast holes, at many different mines, are represented by the examples given in the attached tables; to give further examples would only mean, unnecessary repetition. At the Mount Morgan Mine...

Jan 1, 1952

By A B. Christie

Space-based synthetic aperture radar (SAR) data is becoming available over much of the world, includingNew Zealand. Radar imagery has a number of very advantageous features, including all-weather capability; it also has artifacts, such as layover, which require processing before these data may be used to best effect.   This paper gives an outline of SAR, details the image processing required, and discusses the use of the first New Zealand Japan Earth Resources-1 SAR data to aid geological mapping on the Coromandel Peninsula.

Jan 1, 1994

The National Economic Viewpoint? Any substantial project undertaken by private enterprise would normally be subjected to a Discounted Cash Flow analysis of its commercial viability, and would proceed only if the rate of return was judged satisfactory. A 'national viewpoint' analysis attempts to do the same but from the viewpoint of the community as a whole. The objective is to ensure that those projects are undertaken which yield the best return, economic and social, to the nation as a whole.

Jan 1, 1984

By S Jahanshahi

In an earlier LCA study, the authors showed that the electricity consumption of the electric furnaces used in the production of the ferronickel and ferrochrome feedstocks made significant contributions towards the Gross Energy Requirement (GER) of stainless steel production, on a æcradle-to-gateÆ basis. Given the relatively low efficiencies associated with electrical power generation, substantial reductions in the GER for stainless steel production could be anticipated if more direct use of thermal energy was made in the ferronickel and ferrochromium smelting stages.In view of these findings, a follow-up study was undertaken to investigate the likely environmental benefits of using bath smelting processes for the production of ferronickel and ferrochromium compared to the traditional rotary kiln-electric furnace processes, but still utilising the electric furnace process for stainless steel production. The METSIM process simulation software package was used to set up models of the two bath smelting processes and provide process energy requirements that were incorporated into the LCA. The environmental impacts considered in the LCA were greenhouse (Global Warming Potential, GWP) and acid rain gas (Acidification Potential, AP) emissions and solid waste emissions.The results of the study showed that the bath smelting route reduced the GER for ferronickel production by about 37 per cent over the traditional route, which translated to about a 21 per cent reduction in the GER for stainless steel. The corresponding reduction for ferrochromium was about half that for ferronickel, and when combined with the ferronickel result gave a 25 per cent reduction in the GER for stainless steel production. Similar reductions were also observed for the GWP and to a lesser extent the AP for both feedstocks, as all primary energy inputs were essentially fossil fuel based. Substantial reductions in solid waste emissions were also indicated for the direct use of ores in smelting. By utilising bath smelting processes for the production of the ferronickel and ferrochromium feedstocks, stainless steelÆs suitability for meeting many of the goals necessary for sustainable development, already recognised because of its particular properties, would be even further enhanced.

Jan 1, 2004

By U Briem, R Verreet

The level of wire rope technology used in mine hoisting applications has a significant effect on the overall efficiency of the hoisting system. This paper discusses the effect that a reduction in rope mass per unit length and an increase in rope breaking strength can have on rock skip capacity and hence mine shaft output. A 20 per cent reduction in rope mass per metre for a typical 48 mm hoisting rope, while maintaining the breaking strength, increases the skipÆs capacity by circa 30 per cent at a suspended rope length of 3000 m. Such gains in shaft output, without any significant changes to the shaft or winder design, can have major implications for the feasibility of future deep mine projects. The technical challenge for rope manufacturers is how to get rid of 20 to 30 per cent of the rope mass while keeping the breaking strength and modulus of elasticity of the whole rope constant. CASAR are currently developing steel wire rope constructions where the steel IWRC has been replaced with high strength, high modulus fibres such as Kevlar«, Spectra« and Dyneema«. One of the key aspects of such composite rope designs is to ensure equal load sharing between the different rope components, ie in proportion to their area. If there is a significant difference in modulus between the fibre core and the steel outer strands, the core may not carry its proper proportion of the load and the outer strands would be overloaded. Some technical aspects of the design of composite steel wire ropes are discussed. A design and operational issue that needs careful consideration is the safe non destructive testing (NDT) of composite ropes. Traditional magnetic NDT would only be capable of inspecting the steel wires. Techniques therefore need to be developed that would give operators a reliable indication of the condition of the load bearing fibre core. This paper also discusses possible solutions to this very important NDT question.

Jan 1, 2005

Background A recent development in many industries,' including the mining industry, has been ever increasing acceptance and adoption of extended (12-hour) shifts and compressed work cycles compensated by more time off work by employees between cycles. In the Western Australian mining industry development of `long-distance-commute' (LDC) coincided with adoption of 12-hour rotating shifts. Preludes to LDC were the `construction-style' rosters with two crews plus allowance for annual and sick leave relievers working the statutory 13 consecutive shifts followed by one shift off. Crews rotated day to night shift weekly or at fortnightly intervals. Average hours of 72 to 78 per week were common. The author had personal experience working these rosters in the East Pilbara of Western Australia from 1977 to 1982. Workers tolerated these rosters until a suitable combination of frustration, boredom, despair and the `Five Grand Fever' triggered them to `pull the pin' and head for relaxation in Bangkok, Manila, Nimbin, or Margaret River according to their personal tastes.

Jan 1, 1996

By A Sinuhaji, R Poedjono, G Flumerfelt

PT Freeport Indonesia is currently building the DOZ mine. It is a 25 000 tonne/day block caving operation which is scheduled to reach designed production levels by the fourth quarter of 2002. This paper describes some of the issues and challenges faced by the operation when introducing a new undercut method part way through the project. Advantages and disadvantages are discussed as well as the expected benefits of the new method.

Jan 1, 2002

By R L. Brathwaite

The mesothermal quartz-scheelite lodes of the Wakamarina valley are one of twelve known mined or prospected gold-bearing areas in the Marlborough Schist. Recorded production was 556 kg gold, a little silver, and c. 390 t scheelite. 134 m of the 1800 m long Golden Bar reef are accessible in the No 2 level of the Golden Bar mine. The reef is a typical multi-banded mesothermal vein, mostly c. 1.75 m wide, enclosing narrow horses of schist country rock. Scheelite is sparsely distributed, and is more common in small veinlets in the hanging wall schist. The country rocks are textural zone I-1m schists of prehnite-pumpellyite to pumpellyite-actinolite metamorphic facies. Their geochemistry suggests they are part of the Caples Terrane, and of calc-alkaline volcanogenic arc origin. The associated Wakamarina Quartzite is strongly recumbent folded, and of the same metamorphic grade, with abundant pumpellyite, stilpnomelane, and garnet, presumably spessartine. Although it has geochemical signatures of a deep sea sediment, it is depleted in Cr and Cu, and greatly enhanced in K and Ti, when compared with a standard chert. It also has trace element characteristics of a calc-alkaline arc-related sediment. However, associated greenschist has MORB-like incompatible element chemistry. The Golden Bar reef lies within a steeply dipping, normal to transtensional dip-slip fault adjacent to a shallow-dipping mylonite shear zone, which, at least on the footwall side, is 040 m wide. The shear foliation has been severely dragged down to nearly parallel the Golden Bar reef within 1 m of the quartz lode. Preliminary structural analysis suggests that the shear zone is extensional. X-ray diffraction analyses of the wall rocks show a progressive depletion of amphibole, stilpnomelane, and pumpellyite towards the reef, and enhanced illite/muscovite and Kfeldspar adjacent to the lode, along with possible graphitic carbon within 10m. Two zones of intense quartz veining occur, one adjacent to the hanging wall for 12 m and one from 40 m outwards. Quartz vein systems in the country rock are complex and span from pre-schistosity to post-mylonite. They include multiple generations of quartz, actinolite, stilpnomelane, pumpellyite, albite, adularia, chlorites, illite/muscovite, calcite, and scheelite. Metal analyses across the Golden Bar reef showed gold values of 0.13.1 ppm, and low tungsten values, consistent with the observed sporadic scheelite occurrences. As and Sb are at background levels, but enhanced Cr (150 - 430 ppm) relative to the schists (30 - 41 ppm) suggests that the source hydrothermal fluids passed through and leached mafic to ultramafic rocks.

Jan 1, 1994

Computer programs for the storage, retrieval and use of basic thermodynamic and physical property data for chemical substances are described. Methods are presented for the collection, critical assessment and pre- processing of source data for files containing enthalpy, entropy and heat capacity data for 3000 compounds, enthalpy and excess entropy for 200 dilute solutions and critical propert- ies and vapour pressure for 600 compounds. Retrieval programs are discussed which allow the tabulation or plotting of many basic and derived thermodynamic properties for chemical substances or balanced reactions. Examples are given of the use of such data to infer the stability or corrosion resistance of materials and the feasibility, yield and heat release of reactions. A general purpose calculation program is discussed which allows the equilibrium compos- ition to be found for complex systems with many species and phases, using the method of Gibbs energy minimization. Methods of correction for non-ideal behaviour in these systems are discussed, as well as methods for fixing, maximizing or minimizing any desired property of the system. Examples are given of the simulation of various laboratory Experiments and industrial processes by this method.

Jan 1, 1977

By Rokot M

In a little over three years, Chevron Niugini has built up a team of relatively young, hard working men and women, mostly Papua New Guineans, who spend most of their working days out among people in the Southern Highlands and Gulf Provinces who are directly affected by the Kutubu Petroleum Development Project. These are Land and Community Relations officers, or LACROs. They take on a huge responsibility, not only representing Chevron but also being friend, advisor and negotiator, frequently dispensers of medicines, and agricultural advice and more. When things go well, others get the praise, when things go wrong, LACROs are the martyrs. Just as the geologists who locate the oil, the drillers who find it, the engineers who design the facilities, the construction gangs who build them, the landowners who claim it, and the Government who monitor it, so are the LACROs part of a team.

Jan 1, 1991

By P Cameron

MetPlant conferences have focused on ensuring mining projects are well designed then optimised to operate safely and effectively at the top end of world’s best practice to ensure shareholders are not just happy but delighted. This assumes the MetPlant was built right the first time. However, reality is, too often Plant Metallurgists (PlantMets) find after commissioning they are faced with the expensive task of correcting errors or modifying shortcomings to achieve product quality at name-plate capacity, i.e. get it right the second time. Why do companies spend good money to engineer an excellent feasibility study then allow “wise men” remote from the project team to impose cuts in budget and schedule, often under the guise of value engineering? Since mining is full of uncertainties, such actions can increase the risks of failure with the result that some MetPlants do not work well. Can PlantMets influence the remote wise men who often are also imposing the rules for lending and the required returns to appreciate the uncertainties of mining and their associated risks then let the project team get it right the first time? PlantMets can negotiate with the wise men from the outset of the project and bring them into an outer layer of the team where they can understand the risks then share responsibility and accountability to achieve the common goal of building a MetPlant which works well the first time and deliver the forecast profits. Since shareholders are not in the business to make losses they appoint a Board of Directors to deliver the best outcomes for the shareholders. Thus the Board should seek effective advice on the risk reward implications from the PlantMet before making their decisions.CITATION:Cameron, P, 2015. Do all metplants work well? PlantMets can ensure they do, in Proceedings MetPlant 2015, pp 2–9 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By N Taylor, P Hewitt

The Northern Beaches Storage Project (NBSP) is part of Sydney Water’s SewerFix™ Program to improve the wastewater system and protect public health and the environment. It was built by the SewerFix Wet Weather Alliance (the Alliance), a partnership between Sydney Water, RPS, MWH, Parsons Brinckerhoff and United Group Infrastructure.The project temporarily stores excess wastewater diverted from the Narrabeen Submain during wet weather. The project considered a below-ground storage facility, which involved constructing a deep tunnel from Brookvale to Fairlight, connecting into the Northside Storage Tunnel and a storage tank, which was subsequently adopted and constructed.The storage tank scheme included a pumping station and inlet and outlet pipes installed by microtunnelling. The storage tank site is in the Brookvale industrial area situated in an area of deep marine sediments overlying Hawkesbury Sandstone at about 30?m below ground. Microtunnelling for the inlet pipe was conducted from a 12?m deep jacking shaft. The jacking shaft and 14?m deep pumping station excavations were carried out from within secant pile earth retaining structures adjacent to existing buildings.Construction activities had the potential to cause settlement of the adjacent buildings. During excavation and microtunnelling the water ingress, adjacent groundwater level and settlement of the adjacent buildings were monitored. The monitoring data was assessed against an action plan, which modified construction activities as required to minimise the risk of damage to buildings from settlements caused by lowering of the groundwater table outside the excavations. The secant pile construction, excavation, microtunnelling and pumping station construction proceeded without incident or damage to adjacent buildings.This paper highlights that tunnel/underground options should be considered during options development, describes the original storage tunnel scheme and presents details of the successful microtunnelling and deep shaft construction adopted on the NBSP.CITATION:Taylor, N and Hewitt, P, 2014. Tunnelling on Northern Beaches Storage Project, Sydney, to improve water quality, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 451–458 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By D W. Airey

Frictional rock bolts are widely used because of their low cost. However, they have a thin wall section that makes them prone to corrosion, and they cannot be relied on to provide long-term ground support. It is difficult to assess the capacity after the bolts have been installed as they can only be pulled out if this has been allowed for during insertion. The questions of how long can the rock bolts function effectively and the effectiveness of various surface coatings, which can have significant cost implications are, investigated in this study.A series of accelerated corrosion tests have been performed on frictional rock bolts. The rock bolts, typically 900 mm long, have been inserted into concrete cylinders produced using a styrofoam insert to create the hole for the bolt insertion. Strata rock bolts with four surface coatings have been tested: uncoated black steel, galvanised, enduro (plastic coated) and coated with a proprietary aluminium/zinc alloy. Tests have been performed on two diameters of bolts. Following insertion of the bolts, the concrete cylinders were placed in a large drum filled with saltwater and current was applied to accelerate the corrosion process. The rock bolts were then extracted at various times after the commencement of corrosion. Comparison of the insertion and extraction resistances shows that corrosion initially increases the bolt resistance and that substantial section loss is required for the bolt resistance to drop significantly.CITATION:Airey, D W, 2014. Laboratory corrosion tests of frictional rock bolts, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

Laboratory tests were conducted to study the effects of thrust or pull-down force and rotary speed on the vibration signatures of a particular drill in a known rock type, and to determine how the vibration signatures could be used to assess bit wear. The vibration signatures were analysed using a Wavelet Transform analysis technique, which decomposes the signals in multi-bands of frequency and presents the results simultaneously in time and frequency domain. Results show that as the bit wears, large fluctuations in amplitudes in the high frequency ranges occur, and prominent peaks in the low frequency ranges were observed for a worn bit. The Wavelet Transform technique provides an appropriate and effective metrics for monitoring and evaluating the state of wear as drilling progresses through the post-processing of wavelet coefficients. This study provides a basis for the development of an on-line detection technique of bit wear in rock drilling through Wavelet Transform technique or time-frequency analysis that can be used in real time.

Jan 1, 2000

By Cornwell P. J

The Pajingo ore bodies consist mainly of auriferous quartz veins hosted by a suite of hydrothermally altered andesitic pyroclastics, volcanics and epiclastic sediments. Scott lode, the main economic deposit in the area, lies in a zone of major structural disruption and contortion. High grade gold and silver mineralisation is selectively mined by open pit methods. Standard grade control techniques and extraction methods were adapted to minimise mining dilution and to maximise metal recovery. Basic blending of grade ranges at the crusher has produced an average 10 gram/tonne gold head grade. The estimation of ore reserves calculated by both standard polygonal and geostatistical methods proved acceptable. Mineable reserves when compared to in pit reserves defined by blast hole drilling, indicate a decrease in tonnes and an increase in the grade resulting in an acceptable comparison of the total ounces of contained gold. The ore reconciliation of mined against milled ounces indicates that both ore reserve and grade control models underestimate the metal content in the orebody. Sampling techniques are being examined in an attempt to reduce this discrepancy.

Jan 1, 1989

In considering the preparation of any paper concerning bearing metals, one feels a certain amount of diffidence in venturing into a field which has been capably explored at great length and in great detail during recent years. Many excellent articles have appeared in technical literature, dealing with the general theory of bearings and of bearing metals, the properties of white metals of the tin-base and lead-base types, and of the recently developed lead-bronzes.The justification for this further excursion into the field lies in the fact that it treats a branch of the bearing metal family which has so far received very little attention, and that of a somewhat sketchy nature, in published papers.The author's object is to give some outline of the history, development, present status and possibilities of the cadmium-base bearing metal alloys, particularly those in which copper is the main alloying element.GENERAL CONSIDERATIONS.It is desirable that attention should first of all be given to the general theory, constitution, and necessary attributes of bearing metals, in order that some of the problems met with during the development work may be better appreciated.Despite some evidence to the contrary, it is fairly generally maintained that an alloy for bearing metal use should be of a heterogeneous nature. It should consist of particles of a hard constituent uniformly distributed through a softer matrix.The basic idea is that the hard constituent should actually bear the load and resist wear, while the matrix imparts the necessary ductility and allows the bearing to align itself on the shaft in service.

Jan 1, 1934

The ore milled from the Lead Lode of The Zinc Corporation leases consists of a fairly granular mixture of galena, marmatite, chalcopyrite, tetrahedrite, pyrrhotite, pyrite, and lollingite with a gangue association of calcite, quartz, bustamite, rhodonite, mangan-hedenbergite, garnet, fluorite, mangal1o-calcite and apatite. The silver content of the ore occurs in three minerals-tetrahedrite, dyscrasite, and pyrargyrite, the last two mentioned occurring in microscopic association only. Other metallic and gangue minerals are also present in this complex mineralogical association, but do not influence the milling operations. Fortunately, the silver minerals favour the galena and chalcopyrite as their host minerals, thus facilitating the recovery of both copper and silver in the lead concentrate. The ore from the Lead Lode assays from 14-18% lead; 3·0-4·5 oz. silver per ton, and 9·5-12·0% zinc.A parallel lode, known as the Zinc Lode, is well developed in The Zinc Corporation leases. This lode assays from 6-8% lead, 1·5 oz. silver per ton, 18-25% zinc with a siliceous gangue. The common Lead Lode gangue minerals-ealcite, rhodonite, bustamite-are very rare in present underground exposures. No metallurgical work was done on this ore during the pilot plant operations.The aim in the milling process is to produce: 1. A lead concentrate with the maximum economic recovery of lead, silver, gold, copper and antimony, and minimum zinc content.2. A zinc conc,entrate with the maximum economic recovery of zinc, cadmium, and cobalt, and minimum iron, arsenic and fluorine content.3. A waste residue containing sufficient granular material to be utilized as underground fill.In considering the economics of the milling practice the above three requirements plus consideration of the tariffs submitted by the purchasers of concentrates were the deciding factors in the evolution of the present milling practice.Towards the end of 1924 The Zinc Corporation Limited added to and adapted the old zinc tailings plant for the treatment of 5,000 tons of crude ore per week. This plant, which operated until January, 1936, was in general principles similar to the standard Broken Hill methods of ore concentration, whereby the galena was recovered by the gravity concentration methods of Hgging and tabling with selective flotation concentration of the residual galena and marmatite. One important difference from other Broken Hill plants was that the primary grinding of the jig tailing was performed with flint-loaded mills operating in closed circuit with revolving screens. Two primary grinding sections were installed, each...

Jan 1, 1941

The Callie Underground Mine is located in the Tanami Desert 560 km Northwest of Alice Springs in the Northern Territory and is currently operated by Newmont Australia Limited with all mining activities carried out by Henry Walker Eltin. Callie was discovered in the region in 1991 with the box cut portal commenced south of the pit in 1995 and underground ore production commenced in 1998, after completion of the profitable Callie Open Pit. Development is currently occurring at depths of over 700 m with the decline currently below the 640 Reduced Level (RL) level (surface RL of 1400) with production haulage from 600 m below the surface. The combination of auto compression, a moderate geothermal gradient of 2¦C/100 m and diesel heat transfer causes the wet bulb temperature of intake air at the bottom of the mine to be typically 5¦C higher than on the surface. Wet Bulb temperatures can be up 5¦C higher again in active areas under secondary ventilation. During the 2002/2003 wet season many activities in the lower levels of the mine were stopped due to miners experiencing adverse heat related symptoms or the temperatures exceeding the Underground Heat Management Procedure stop job criteria of 32¦C wet bulb. To improve the working environment, combat the heat related illness and improve operational efficiency, a temporary 1.8 MW refrigerated cooling plant consisting of three 600 kW modules were installed underground to provide bulk air cooling for the lower levels of the mine during the 2003/2004 wet season. Several studies have been conducted in relation to future ventilation demands at Callie and all came to the conclusion, that some mine cooling will be necessary for Callie to meet the high production and development demands. This paper will describe the ventilation network at the Callie Underground operation focusing on the installation, operation and effectiveness of the temporary underground refrigeration plant.

Jan 1, 2005