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By G D. Carman

White Rock is a reduced tungsten-tin skarn deposit near Rye Park, New South Wales. This abstract summarises the depositÆs mining and exploration history, and current exploration by Paradigm Metals Ltd targeting an economic resource at the deposit. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Blasting in Norwegian mines is often carried out by contractors who tend to look for the cheapest solution, without concern about fragment quality. The requirementsfor a contractor are usually only related to the maximum size of boulders and the quantity per month. Even when the owners of the mine are responsible for blasting, very little effort is made to optimise the blasting process. This paper presents test methods which were used and results from small-scale and full-scale blasting tests. In the small-scale tests, cubes 500 x 500 x 500 mm of four different rock types were blasted in a chamber, using two types of dynamite explosive. The velocity of detonation (VOD) for the dynamite explosives was 3000 m/s and 6000 m/s respectively. Three cubes of each rock type were blasted with each type of explosive, and a total of six cubes of each rock type was used. The entire muckpile (approximately 350 kg) was- sieved and weighed after each blast and fragments between 8-16 mm were tested for impact values and flakiness. The results of these tests clearly showed improvement in fragmentation the closer the acoustic impedance ratio of the explosive (VOD x density) over the rock (Cp density) was equal to one. The results also showed that the quality of the fragments (in terms of impact values) tends to be better when the cubes are blasted with the high velocity dynamite.

Jan 1, 1995

By Miller J. D

The mechanism of adsorption of gold from alkaline cyanide solutions by carbon has been the subject of much research over the past decade. In this paper, the nature of the gold cyanide adsorption phenomenon is investigated, particularly with respect to carbon substrates and associated surface adsorp- tion sites.

Jan 1, 1991

By J Rutter, M NoppT

Ridgeway Gold Mine is part of Cadia Valley Operations which is wholly owned and managed by Newcrest Mining Limited. Ridgeway is an underground sublevel cave (SLC) operation mining approximately 5.6 Mt of gold-copper ore per annum. Ore tracking and accounting systems monitor gold and copper grades, copper mineralogy, host lithology and ore sizing. These factors have material impacts on concentrator throughput and metal recovery. Drawpoint recovered grades are routinely reconciled back to design data to monitor and assess draw performance. Grade control at Ridgeway has been based upon sampling the ore from SLC drawpoint bunds using 15 kg grab samples combined to form 30 kg samples prior to assay. This large sample size was selected in an attempt to representatively sample the coarsely-sized broken ore, the samples collected having a nominal diameter of about 130 mm. The assay results for gold and copper from these samples are extremely variable and the usefulness of the results has been questioned by the mine, particularly given the onerous and OH&S hazardous activity of handling large sample masses. Granulometry testwork at Ridgeway confirmed the extent of the relationship of decreasing sample grade variability with particle size. Based on this relationship, drawpoint sampling tests were carried out using 9 kg samples sieved to -45 mm at the drawpoint site. The gold and copper results from the finer 9 kg samples were significantly less variable than those from the normal, coarser 30 kg samples. The variance reduction was similar to that predicted from broken ore sample theory for the selected sample mass and nominal particle size. This relationship therefore allowed Ridgeway to assess the sample mass and particle size required to achieve a particular precision. In addition to improving the precision, the reliability of assay results from smaller samples from the fine particle fraction for drawpoint control depends on the accuracy of the results. The assumption is that the grade of the finer ore is similar to that expected from the lot, or that if a bias exists, then the extent of this bias is acceptable and consistent enough to be accounted for in the grade control system. The distribution of grade with particle size and the reconciliation of drawpoint sample and mine results is currently under investigation.

Jan 1, 2005

In 1969, Queensland Mines Limited obtained two large Prospecting Authorities in Arnhem Land, Northern Territory, Australia. The Nabarlek uranium deposit containing some 12 000 t of U308 was discovered on one of these in June 1970. Mining and stockpiling of this deposit were completed in 1979 and processing to yellowcake, which commenced in June 1980, is expected to occupy an 8-10 year period. The continuation of exploration, essential for the company to become a longer- term producer, was inhibited in 1972 by a Federal Government "freeze" on exploration in Aboriginal Reserves in the Northern Territory. Subsequently, the procedure for explorers to gain access to exploration areas in Aboriginal land was radically changed by the proclamation of the Aboriginal Land Rights (Northern Territory) Act 1976. As a result of this Act and the associated administrative policies adopted by Governments, Queensland Mines Limited has not yet regained access to the exploration areas it formally held in the early 1970's.

Jan 1, 1986

By C Fearon

This paper discusses the implementation of an underground rail haulage system during a major expansion of the Olympic Dam mine in 1998. The factors affecting the selection of rail haulage are discussed and details are provided on the rail system, which is designed to transport more than 10.5 million tonnes per annum (Mtpa). The reliability of the system during commissioning is discussed, including the decision to manufacture a ædummyÆ locomotive in order to keep the system operational. Finally, reliability improvements made both during and after commissioning are discussed with comments provided on the effectiveness of the system as it operates today.

Jan 1, 2005

By P F. Knights

Mining companies are striving to achieve new levels of operational maturity and drive process improvement across the organisation in the face of unprecedented demand and limited supply of experienced human resources. Advanced analytics techniques can help overcome these fundamental challenges by applying data techniques not previously applied in mining. Today, decisions are usually locally optimised but do not achieve optimum capability for the value chain. Although more information is collected then ever before, it is difficult to link many sources of data together in the same place in real-time, for example plant history, maintenance, mine planning, logistics and engineering data. Consequently complex analysis of data is time consuming and requires specialist skills and knowledge, and is often neglected in the decision-making process. In the future, analytics will close the loop between analysing data and taking action. Analytics will become embedded in the business and routinely applied to improve decision making across the organisation, from senior management to operations and maintenance workers, but will not require specialist skills or be time consuming to analyse data. As analytics becomes embedded in the business process, decisions are supported by data (not on gut feel), and critically, data from many sources are integrated in real-time to improve the quality of decisions. Ultimately, predictive tools will help suggest, or even in some cases automate, courses of action. The main opportunities for analytics exist where the enterprise requires supporting technology to enable it to continue to evolve to higher level of maturity. This will be in the areas of asset management, rapid reconciliation and adaptive planning, and the inbound and outbound supply chains. Advanced analytics are also a key enabler for increasing the effectiveness and realising the true value of Remote Operations Centres to safely and efficiently support operations in remote locations with smaller workforces.

Jan 1, 2008

By A J. Tucker, L Bottomley

The principle objective of development mining is to create thoroughfares that can be accessed by personnel and machinery for the entire life of an underground mine. The drill and blast process, being the primary method used when creating these thoroughfares, needs to be able to adequately fracture the rock to be removed whilst at the same time minimising any damage that may be sustained to the rock surface that remains. This process of damage prevention is known by a variety of different names including smooth blasting, sculpture blasting, contour blasting and controlled blasting. Whilst the terms are different, the objective is the same and that is to reduce and better distribute the explosive charges to minimise stressing and fracturing of the rock beyond the neat excavation line. The process in this report will be referred to as perimeter control blasting. This paper will discuss the benefits of using perimeter control blasting in a development mining operation and the theories that govern how these blasting techniques work. The methods that are used to implement perimeter control blasting will also be addressed, paying particular attention to how these blasting techniques have evolved, spawning new and improved perimeter control products. Finally some attention will be given to the process of optimising perimeter control blasting in any underground mining operation.

Jan 1, 2005

By R. A. Frith, M D. Goodz

Ore-bearing minerals that are located along microfractures are always susceptible to loss during the breakage and sampling of the material. Further losses occur with on-site sample preparation and splitting prior to laboratory analysis. In these cases solid whole rock channel or core samples should be handled with due care to ensure all fines and loose particles are collected and included in the sample for total chemical analysis.Similarly open hole and reverse circulation drill methods are not usable in areas containing old mine workings, heavily fractured ground or highly degraded/oxidised mineral assemblages. Nor are these methods usable to assess a bulk mineable target where the enriched zones were peripheral to or between old mine cavities.

Jan 1, 1993

By A G. Greenwood

Research into cemented rock fill at Mount Isa Mines Limited since 1992 is described. The key mechanisms controlling segregation during stope filling with cemented rock fill are described and include the gravity flow mechanism which is described in detail. Examples are provided to demonstrate these mechanisms. Comparisons are made between Mount Isa MinesÆ cemented rock fill and slurry-based cemented rock fills. Recent backfill stability modelling using a three-dimensional finite element program is described.

Jan 1, 1998

By Kyle J. H, Misra V. N

The recovery of copper from a flotation concentrate using ferric chloride leaching has been investigated. The concentrate from the Horseshoe Lights Mine near Meekatharra, Western Australia, contained mainly digenite, pyrite and talc minerals. Over 95 per cent of the copper was dissolved in an acidified ferric chloride solution in one hour at 70¦C and ambient pressure. The pyrite and gangue minerals did not react. The leaching process was found to consist of four separate reactions and the shrinking core model was used to describe the process. The effects of particle size, temperature, concentration of FeCls, stirring speed and leaching time on metal dissolution were investigated. The apparent activation energies in the second, third and fourth reactions of leaching of copper concentrate were 28.8, 11.9 and 53.9 kJ/mol, respectively. The optimum conditions for the leaching of copper from the concentrate, within the range of conditions studied were: particle size 63 per cent minus 38 ¦m, a ferric chloride concentration of 1.48 M, a temperature of 70¦C, and a stirring speed of 800 rpm.

Jan 1, 1991

The necessity for good management and economic working in our mines and ore-dressing sheds is impressed upon us by the present low prices of all our metals. Silver, lead, copper, and tin have all suffered a heavy decline during the last six or twelve months, and many mines have been shut down simply on account of the low market value of the ore produced. After fully considering the position of the mining industry. I am convinced that considerable improvements will have to be made to make it as prosperous as it ought to be. The most obvious of these improvements are good management, good machinery, and as little interference by directors as possible. If these conditions are insisted upon and carried out efficielltly a poor mine may have a chance to weather the storm.There is no doubt that the present depression is the refilult of over-speculation and general loss of confidence by which the whole commercial system has been affected, and every branch has suffered more or less, mining not excepted. It has suffered heavy losses in the past, and the future is not over bright we are, therefore, compelled to be careful in everything by which mining is affected and savings can be secured.

By H R. Phillips

Fresh air intake in an underground coal mine is of critical importance to the occupational health and safety of workers due to the dynamic, confined and dangerous nature of the mining environment. In most coal mines in South Africa, belt road is not separated from the fresh air intake to the sections. Intake air to coal production faces generally contains dust generated by conveyor belts, transfer points and travelling roads. Long roadways (up to a few kilometres in some of the existing mines) to the coal sections are involved in the ventilation circuits of individual sections. This leads to a progressive increase in the dust levels in the intake fresh air and thus high dust levels in the air delivered to the working sections downstream. In the process of reducing worker exposure to dust in the face area, attention to the monitoring of fresh intake air is generally given a low priority. This paper summarises the intake dust levels measured in selected South African underground coal mining sections over the past five years and its use as a parameter in assessing worker exposure to dust through a newly developed model called the Dust Exposure Level Index (DELI). Based on the measured data of the South African coal mines, the average section intake dust level was 0.78 mg/m3. Approximately 60 per cent of the samples collected for the study have exceeded the 0.5 mg/m3. The intake dust level measured at a longwall face was much higher than in the CM headings. The measured section intake dust levels furnish the South African coal mining industry with the latest depiction of the level of face area dust contamination due to the intake air. Further, this paper demonstrates the use of intake dust level as a parameter in estimating exposure levels of workers, as it clearly plays as a corner stone in effective control of exposure to face area respirable dust. It must be borne in mind that intake dust is a base level to the mine worker exposed to dust without carrying out any additional work in the section. If the intake air is seriously contaminated by airborne respirable dust; then the exposure of the workforce in the section will constantly be elevated by that background dust level.

Jan 1, 2005

The Golden Valley Volcanic Centre has been recently interpreted as being a combination diatreme breccia pipe and rhyo-dacite flow dome complex of Permo-Carboniferous age that intrudes basement granitoids and sediments of Ordovician-Devonian age. Exceptionally good exposure at the Centre has enabled the relationships between different lithologies to be determined. This, along with petrological studies, has led to a detailed understanding of the geological environment in which the complex formed. Gold, silver and base metal mineralisation have been recently shown to be associated with the Marginal Breccia at the perimeter of the diatreme. Comparisons have been made between the geology and mineralisation in this system and several similar diatremes which also contain gold-base metal sulphide mineralisation.

Jan 1, 1990

By Paine G. G

The Red Dome Gold/Copper Mine is located approximately 15 km west of the township of Chillagoe which itself is approximately 220 km by road west of Cairns, Far North Queensland. The deposit, with other mines in the Mungana region, was worked from about 1901 to 1927. Exploration by Amoco Minerals Australia in the 1970s and early 1980s outlined a geological resource of 15 million tonnes. A mining reserve of 9.3 million tonnes was identified and originally developed by Elders Resources Limited. The mine commenced operations in March 1986 and was the first large-scale gold project in Australia to be developed solely on the heap leach process. The mine operated successfully as a gold heap leach operation until 1989 when new grinding, flotation and carbon-in-leach plant facilities were installed to process the non heap-leachable component of the orebody including the copper rich -ore. In March 1991, Red Dome Pty Ltd became a wholly owned subsidiary of Niugini Mining Limited. After six years of successful operation and having excavated a 200 in deep pit, it became evident in 1992 that unless more open cut reserves could be identified the operation was limited to six to nine months of high grade ore and a further 15 months of low grade stockpile material. A preliminary feasibility study was carried out to assess the viability of deepening the open cut. This indicated that from a technical and financial point of view it was possible to expand and deepen the open cut. This presented the daunting challenge of developing a 300 in deep, single access, open cut between a high chert ridge, a government railway line and a National Park. The meeting of this challenge is the subject of this paper.

Jan 1, 1994

By S K. Schwank

Trench cutter systems have been used in civil engineering for the least 30 years for the installation of deep cut-off walls, retaining walls and foundation systems. The systems are constantly advanced to achieve greater depth, penetrate through harder rocks a provide a bigger footprint of the cutter. The state-of-the-art equipment can reach down to 250 m vertical depth and penetrate all different types of soils and rocks up to 150 MPa unconfined compressive strength.In mining, especially in commodities with a high value and where the ore deposit has a small footprint, cutter mining with vertical attack from the existing ground level will be a new, cost-efficient approach where conventional open pit mining is not economically feasible due to a high stripping ratio. The same applies for open pit mines that have reached the end of their conventional mine life and where going underground is also uneconomical. The BAUER Cutter Mining System, which has been adapted to the special needs of mining, is a new technology that will allow mining at depths of up to 250 m.The same system can be also applied to ore dykes, be it vertical or slightly inclined, concentrating the excavation on the actual orebody and minimising the strip ratio and the contamination of ore. The system can be adapted to the dimension of the dykes or veins and to the rock conditions.BAUER’s latest approach is to use the vertical cutter mining technology for the extraction of sea floor massive sulfides from the seabed in deep ocean waters. Due to the compact footprint of the system and the vertical attack for mining, extraction of the ore can be concentrated on the hot spots, minimising the environmental impact on the sea floor both for mining and manoeuvring the remote-controlled mining tool.CITATION:Schwank, S K, 2015. Cutter mining – crossover technology from civil engineering to mining, in Proceedings Third International Future Mining Conference, pp 95–100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

A new experimental procedure for determining the solids flux curve is detailed. The procedure is based on measuring the concentration at various heights of a bed of settled solids formed during a semi-continuous sedimentation test. Unlike conventional thickener area calculations, the test procedure demonstrates the dependence of the flux curve on the system feed flux. At a given feed flux, there was good agreement between the solids flux curve determined by the method and continuous sedimentation results. The widely used method of Kynch was found to be restricted to relatively high effective feed fluxes and consequently there was poor agreement with continuous tests at low feed fluxes. The flux curve determined by the method of Coe and Clevenger was invalid for all feed fluxes. A case study shows how the required thickener area would vary for a number of fine coal processing options.

Jan 1, 1989

By Blair J. R

A Train Performance Calculator (TPC) is an essential tool in railway operations, as a means of acquiring quickly a precise measure of the performance of the system. Traditionally the TPC was used in the form of program for a large computer. By employing an efficient integration algorithm and tailoring the program to suit the computer system it is shown that it is possible to devise a TPC for a mini computer. The resulting low running costs and flexibility of operation makes this a useful design tool. This TPC was developed to study problems associated with a single track railway operation. It was applied specifically to study the railway operated by the Mt. Newman Mining Co. Limited in the Pilbara region of W.A. to transport iron ore from the mine to the port. The TPC was used to calculate the effects of changes to locomotive power, to train size, to the track and to the amount of traffic. Its accuracy was checked by comparing its performance with that of the actual trains.

Jan 1, 1977

By S N CARRAS

Ore reserve estimation is a procedure involving data collection, data storage and judgement and assumptions about geology mining and metallurgy. Calculations are based on these assumptions and an economic analysis on projected cash flows is carried out. Ore reserve estimation must therefore be subjective and will always depend on the extent to which the assumptions used in arriving at the estimate are correct. This paper is an attempt to summarise the many aspects that can contribute to ore reserve problems and to offer some suggestions on how to minimise these problems. For further details on specific concepts readers are referred to the detailed descriptions in the referenced papers.

Jan 1, 1992

By Feilding C

Vitrinite of humic source (often designated as vitrinite A) is the maceral by which the rank of a coal ought to be determined. Therefore its recognition, and the precise identification of other vitrinites is essential. The majority of Australian petrologists are not differentiating between the vitrinite group macerals in maturation studies, the results of which have led to unexplained phenomena in coal characterisations and evaluation, such as 'reactive inertinites' and inaccurate predictions in petroleum source rock studies. The Callide coal has been chosen as a case study, with examples from other coals. The coal seams from the Callide Coal Measures show variation in the predominance of some macerals, indicating successions of environmental changes. The application of transmission electron microscopy (TEM) to the study of the Callide coal has enabled a better understanding of the nature and origin of some of the less understood macerals such as micrinite and vitrinite B. Two forms of vitrinite have been observed, each with a distinct reflectance range. The wood-sourced vitrinite A displays an average reflectance of 0.56 per cent, and a range of 05. - 0.7, implying a higher rank than the 0.49 per cent Ro total vitrinite reflectance recorded in previous publications. Vitrinite B is one of the most commonly-occurring macerals in the Callide coal. The lower-reflecting vitrinite B which forms bands, often several hundred microns in thickness, in TEM appears to be electron transparent lipid rich. Vitrinite B is interpreted to represent accumulations of leaves, and is believed to be a major source of hydrocarbons in Australian sedimentary basins. The Callide coal has entered the oil window, and oil has been generated from some exinite, cutinite, and resinite, as evident from the amber to light brown fluorescence of exinite and the presence of exsudatinite in cell cavities and cleats. However vitrinite B, the major potential source of oil, is seen under the microscope to be generating oil, thus placing this coal at the top of the oil window. Micrinite, the origin of which has been much debated, occurs as cell filling or infill of spaces between laminations in vitrinite B.

Jan 1, 1991