Search Documents

By Wagland D. G, Guo H

The Mt Whaleback orebody is in a complex geological regime. A good understanding of geological structure is essential during the design and implementation stages. The amount of information on the rock-mass condition available at the design stage is considerably limited. It is essential to validate the rock-mass properties used in the design during implementation. It is important to achieve integrity of the final pit wall during development and to maintain the integrity until the end of its designed life for safe and economical extraction of ore. The original geological model is updated by way of on-going detailed geological face mapping. Original design is reassessed and is modified based on any significant variations to the previously evaluated geotechnical conditions. Information gathered during design implementation provide tools for effective management of the pit walls. Controlled blasting techniques are employed in the final limits blasting. Presplit blasting is used in most limits blasts. Presplit helps to maintain the integrity of the wall by venting excessive gases from the limits blast. This helps to reduce bedding dilation by gas penetration. Also, it helps to define the design batter for the operators for final batter trimming. Pyritic shale needs special attention during blasting due to its reacting nature. Cablebolting is applied in selective areas to secure small-scale potential instabilities. During the development phase, pit wall monitoring instruments are installed. These instruments are used to monitor the performance of the wall during and after excavation of the slope.

Jan 1, 1995

By Morris P. H

A trial embankment was constructed using coarse coal mine reject on a deposit of crusted coal mine tailings at New Hope Colliery, located in the Bundamba District of the West Moreton Coalfields in South East Queensland, Australia. The purpose of the trial embankment was to assess the load carrying capacity and settlement behaviour of the crusted tailings, including an assessment of strength gain in the tailings under the influence of the fill. Prior to construction of the trial embankment, a site investigation of the tailings deposit was carried out. This comprised vane shear strength testing, together with disturbed sampling and undisturbed block sampling for the purposes of laboratory testing. Following the site investigation, settlement plates and standpipes were installed at various depths and locations within the tailings in the vicinity of the proposed embankment. The instrumentation enabled the magnitudes and distributions of settlement and pore pressure within the tailings to be determined during and following construction of the embankment. The embankment was constructed using coarse reject in three equal lifts to a height of 3.0 m. The tailings sustained a maximum settlement under the weight of the fill of 290 mm, representing about 4.2 ii of the average initial thickness of the tailings and a loss of embankment height of about 9.7 %. By the end of the monitoring period the strength of the softer tailings underlying therust had roughly doubled under the influence of tha cmbarikment

Jan 1, 1990

Perhaps no aspect of the investigation of an ore-deposit is of greater importance to the mining geologist and engineer than a consideration of its geological structure. A thorough understanding of the type, size, shape, and arrangement of any ore-body is essential to the proper conduct of exploratory, developmental, and mining, operations. Significant as these remarks are' in relationship to ore-deposits in general, they become of paramount moment when a complex structure such as the Broken Hill Lode is in question. In this connection the use of the term "lode" as applied to the Broken Hill ore-bodies may terid to confusion of ideas among those not familiar with the field or with the literature pertaining thereto, by reason of the fact that it is generally understood that a "lode" is characterised by simple, tabular form, regular outline, defined walls, and persistent attitude. However, as the terminology is well established by common usage, itsretention appears desirable, and, for the purpose of this paper, the name "The Broken Hill Lode" refers to that complex unit which includes pre-eminently the famous ore-bodies exposed in the workings from the North Mine on the one extreme to the South Blocks (Zinc Corporation) Mine on the other.That the practical value of geological investigation, of the ore-bodies was realised by the Geological Sub-Committee of the late Scientific Society of Broken Hill is attested by the...

Jan 1, 1932

By Howell M. W

The purpose of this paper is to outline the main points in the construction of the various types of wire ropes more commonly used for winding in Australia; and the maintenance of the ropes, and cage and skip safety gear as practised at the South mine, Broken Hill.It should be mentioned that both of the shafts at present in use are dry, and both downcast with or without the assistance of the two exhaust fans normally in use: Night shift and week.-end overtime are practicaly non-existent.Thus, during night shift, the cages in No. 7 shaft are landed on the chairs at the surface, providing efficient covers for the· shaft, and allowing the maximum amount of rope to be wound on to the drums. This also applies to the cages of both No. 7 and No. 4 shafts during the week-ends.These factors, combined with electric winding and skip haulage, are calculated to obtain the best use of the ropes when properly attended.WINDING ROPES-TYPE AND CONSTRUCTIONThese ropes may be divided into four main types which will include the more commonly used constructions(a) One-size strand.(b) Warrington strand.(c) Flattened strand.(d) Locked coil.1. One-size strand as the name implies, is a rope the strands of which are constructed 9f wire of the one size.Usually the strands are of 7, 19 or 37 wires.

Jan 1, 1940

By G Johnson, S Michalek, N Redman

As the modification of the 2009 Mill OperatorsÆ Conference theme from æmilling through the boomÆ to æthe boom û experience gained and lessons learnedÆ exemplifies, comminution practitioners are facing a series of challenges in the dramatically changing mining environment. One of the main problems plant managers have been facing during the boom times has been the severe metallurgy skills shortage and high staff turnover, both factors that can cause difficulties in mill liner management. Many of todayÆs mill managers are now also more than ever faced with the need for cost-cutting in order to continue operating viably. Amongst other potential target outcomes such as maximised throughput, MillMapperÖ, a tool for mill condition monitoring and mill performance optimisation, can be utilised to address these issues. This paper demonstrates how MillMapperÆs quantifying decision making tools can serve to be in control of managing mill liner and production issues, and how it can form the basis for mill cost savings without the risks normally associated with conventional methods or the lack of using any condition monitoring methods. MillMapperÖ is currently being referred to at a rate of approximately 150 surveys and associated reports per annum at processing plants in Australasia, South America and Africa. Examples throughout the paper provide insight into how the presented sample set of users have extracted benefits that could have otherwise not been safely or at all achieved.

Jan 1, 2009

The high-shear colloidal mixer is generally recognised as the most efficient method of mixing cement based grouts. Only recently however has this technology been applied to the production of cemented rockfill (CRF) for use in underground mines in North America. Traditionally, paddle type mixers have been used to produce the cement based slurries required for the preparation of CRF. While considerable success has been achieved with these mixers, tremendous advantages are attained with the colloidal mixer. The combined effect of the highly efficient mixing action and the ability to mix low water/solids ratios, allows for reductions in the cement content for a given strength requirement. Cement can also be replaced by cheaper fillers such as flyash, resulting in further cost savings. Although large-scale dedicated CRF batching plants are typical, there is a growing need for mobile plants capable of operating anywhere underground. The compact size and rapid batching speed of high-shear colloidal mixers has allowed them to be incorporated into skid mounted systems capable of producing and discharging cement based slurries onto rockfill aggregate for the production of CRF. In many cases run-of-mine development waste can be used as CRF aggregate with these slurry plants thereby reducing the cost of waste rock removal. These relatively low cost portable plants have now allowed several mines to economically recover isolated pillars and realise positive returns on their investment.

Jan 1, 1998

By P J. Harris, D J. Bradshaw

Surface oxidation of sulfide minerals, such as that found in the regions of a sulfide ore body near the water table, can have a significant impact upon flotation. This theme has been explored for Merensky ore type sulfides where an ore containing pyrrhotite, pentlandite and chalcopyrite was thermally oxidised and the role of potential remedies investigated. Back-scattered scanning electron microscope images are presented showing the oxidation layer which formed in the mineral surfaces. These oxidation layers were depleted in both sulfur and iron with incorporated oxygen. Flotation recovery rapidly decreased with increasing oxidation, particularly after 27 days and reached a plateau after 50 days. Up to 27 days, this effect could be partially overcome with higher collector additions. Oxidation had more impact upon the finer size fractions, particularly for pyrrhotite. For more heavily surface oxidised samples, ultrasonic treatment prior to collector conditioning was found to improve flotation recoveries. This treatment had the greatest effect upon chalcopyrite particles. Sulfidisation was successful in restoring the flotation recovery of the heavily oxidised sulfide minerals. Longer sulfidisation conditioning times were not conducive to good flotation recoveries of both oxidised pyrrhotite and pentlandite due to oxidation of the freshly formed sulfide surfaces. For maximum flotation recoveries of oxidised pyrrhotite, pentlandite and chalcopyrite, different sulfidisation conditions are indicated. It appears likely that in a mineral processing operation treating oxidised Merensky type ores, two stages of sulfidisation employing different conditions would be required.

Jan 1, 2005

By Storey AG

Following initial plant scale work on the development and performance of 'spray' oil lances, a full scale room temperature model of the blowpipe-tuyere region of a blast furnace was built to study the basic aerodynamic features of auxiliary fuel injection procedures. Mobilwax 2305 was used as a substitute for Bunker C oil fuel in view of its similar physical properties and the fact that the atomised droplets could be frozen in flight and size, distribution analyses made for various operating procedures. It was shown that secondary atomisation processes far outweighed the importance of any primary atomisation procedures in determining mean Sauter Diameters particularly at high windrates typical of current blast furnace technology. It was also found that good spray dispersions across the blow pipe could only be obtaind for liquid fuels and that the lateral rate of spray dispersion was substantially enhanced by primary atomisation procedures. Mean particle diameters of sprays were found to be predictable on the basis of elementary stability theory and fell within the size range necessary for good combustion at all liquid fuel rates studied. The possible effects of high oil injection rates on flooding phenomena in the furnace bosh were considered. Comparisons show that high oil rates can lead to significant increases in the hanging factor (e.g. 'V 10% at 135 kg oil/thm) owing to increased gas flow rates/thm resulting from the presence of hydrogen.

Jan 1, 1975

By A Radici, S Russell

The Dampier Port Upgrade was completed in 2007 and is the largest project in Rio Tinto Iron Ore's expansion program. The project doubled Dampier Port's iron ore shipping capacity over a five year period. Sinclair Knight Merz (SKM) was appointed by Rio Tinto as the Engineering, Procurement and Construction Management (EPCM) contractor to manage Phase A and Phase B of the Dampier Port Upgrade. The aim of the project was to increase the Dampier Port capacity from 74 to 140 million tonnes per annum (Mt/a). This increase in shipping capacity tripled the capacity of the Parker Point facility from 34 to 94 Mt/a, whilst the East Intercourse Island facility increased from 40 to 46 Mt/a. The Dampier port remained fully operational throughout construction and achieved record yearly export tonnages over the period of the project. The $US1.4B project was completed ahead of schedule, on budget and with an outstanding safety record. Significantly the project team set an industry benchmark by achieving five million man-hours Lost Time Injury (LTI) free. The project has been recognised by the Engineers Australia 2008 Western Australian Engineering Excellence awards as category winner in resources and the overall winner in WA, and went on to win a National Engineering Excellence award. This paper provides an overview of the EPCM project management and an insight into some of the key drivers that have delivered this outstanding project.

Jan 1, 2009

By Tomlinson R. C

The paper will briefly describe planning in the National Coal Board (NCB) and the contribution that operational research makes to it. It will then give details of some of the models in use and will finally consider critically the problems of looking ahead to the next century.

Jan 1, 1977

In recent years the use of directional drilling has become increasingly popular in several applications. These include shaft pilot holes, exploration drilling, mine service holes and drilling beneath surface structures and obstacles. The prime objectives are to increase accuracy and reduce time, cost and environmental disturbance.

Jan 1, 1992

It is important to prevent the overload ing of mills being operated near maximum tonnage. Changes occurring during overload differ in their usefulness as guides to control action. The Primary Ball Mills of Bougainville Copper Ltd. provide an example of some of the problems and progess in avoiding overload.

Jan 1, 1978

I should like to congratulate Dr. Salamy on his most informative paper.Under the heading of "future development" Dr. Salamy states the intention of using 3 in. lifters. In this connection I should like to mention one or two of our findings at the Croesus Plant of North Kalgurli (1912) Limited. We have converted a 5i ft. x 11 ft. grate discharge ball mill to a high level overflow rod mill. When we were considering this conversion we explored the literature and decided on using 2t in. lifters on alternate liners-the results were not encouraging. The mill all but "took off" from its foundations,and performance with regard to tonnage was poor. There...

Jan 1, 1956

Spectacular high-temperature hot springs (æblack smokersÆ) on the deep ocean floor are producing economic concentrations of base and precious metals. Mining these seafloor massive sulfide (SMS) deposits is about to become a reality in 2010, subject to the timely issuance of permits. Three Australia-based private companies and two government agencies inJapan and Korea have exploration licenses or applications covering vast areas of the seabed in the western Pacific targeting SMS deposits. Technological and financial challenges for recovery of seafloor sulfide deposits are being met and mining these may be less environmentally deleterious than mining on land. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By M Lellis

During the last decades, maintenance has changed from an ordinary repair activity to a complex function that plays an essential role contributing for the companyÆs results. The increasing level of complexity of modern equipment motivates maintenance personnel to improve both techniques, and management systems, in order to face the new challenges. Managing properly those modern means of production requires knowledge of methods and planning systems, controlling and performing maintenance tasks, in such a way that two objectives are achieved at the same time: system efficiency and cost-effectiveness. This paper shows CVRDÆs experience on evolving and implementing a model to plan and manage maintenance activities in order to achieve a higher level of performance on its operations.

Jan 1, 2003

The rare earths market is relatively small and slow growing. Three applications using mainly cerics rare earths : catalysts, glass-ceramics and metallurgy are volume market. Inside this slow moving frame, fast growing niches can be found lamp phosphors, permanent magnets, fine cera- mics... There is no specific ore for one given element, and the natural occurence of any ele- ment is almost constant in both monazite and basnaesite. This creates the "balance problem" that consists in the best compromise between shortage and over production. The general trend of prices is downward in constant money. Despite this difficult environment (price decrease, technology changes, etc...) lots of company have always been attrac- ted by the rare earth business.

Jan 1, 1986

By Watson D. F

P S B Stewart has rightly pointed to a possible obscurity in our paper on drilling patterns, viz. in comparing the improvement of a triangular drilling pattern over a square one, we used percentage improvements without always making clear their base. We hope, however, that other readers, like Stewart, have been able to understand the particular meaning from the context.Although different methods of estimation of an ore deposit will have different local bias (Philip and Watson, 1985), the critical relationship affecting the reliability of estimation of an unsampled location is the scale of local variation of the variable being estimated in comparison with the density and isotropy of sampling. This relationship overrides all other considerations.

Jan 1, 1985

By Goode A, Belby P, Wardell-Johnson M

Within a short time frame of just over two years Wirralie Gold Mine has been developed from a virgin geological discovery to an operating gold mine with a mine life of six years and a production rate of 50,000 oz per annum. Construction work on the 600,000 tpa single stage crushing, two stage milling CIP plant commenced in November 1987 and was completed some seven months later at an overall cost of $A25 million. Since commissioning in May 1988 the treatment plant has exceeded design tonnage, availability and recovery. A second expansion programme in January 1989 will increase plant capacity to one million tonnes per annum with associated bullion production of 80,000 ozs per annum.

Jan 1, 1989

The application of cheap robust microprocessor based units to achieve monitoring and control in an underground mining environment is described. The functional layout of the programmable controller and the methods of multiplexing and processing information from local and remote sources are examined as are features for refrigeration plant control.High noise immunity communication to a remote micro computer uses existing telephone lines and enables display and print of essential data. The development of this system then leads to applications in monitoring compressed air, ore transport and underground fires.In conclusion, the problems of data presentation to different levels of management and the future philosophy of a central multi-reporting system are discussed.

Jan 1, 1985

In a stipulated hard rock situation, drilling and blasting costs per tonne in open cutting or underground operations are comparable. In open cuts the drilling and blasting costs per tonne of ore are multiplied by the waste ratio.Conventional underground loading and haulage practices are so batch-oriented that the cost per tonne of ore handled is a large integral multiplier of open out costs per tonne loaded and hauled.If underground costs are to be reduced to compare favourably with open out costs then loading and hauling practices underground must be converted to a non-batch continuous system. This can be achieved by utilising gravity to control ore to mobile crushers feeding conveyors running direct to surface.

Jan 1, 1985