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Bureau of Medical Inspection, Broken Hill, New South Wales.INTRODUCTIONFor a considerable time it has be3n realised that the pathological changes produced in human lungs by the inhalation of free silica varied, not only according to the amount of silica inhaled, its particle size and the period during which it was inhaled, but also according to other mineral elements which might be admixed with the fine silica dust and inhaled along with it, or inhaled subsequently to the silica containing dust. It was observed that, in many instances, these admixed dusts tended to inhibit the action of the free silica in causing injury to the lungs, as well as the development of certain complications, whilst in other cases it was felt that certain substances could actually accelerate the tissue damage caused by the silica.A fresh impetus to the problem of the prevention of the development of silicosis was given when, in 1937 and 1939, Denny, Robson and Irwin published papers entitled "The Prevention of Silicosis by Metallic Aluminum." Working at the same time at the Saranac La.boratory, and quite independently, and using a colloidal aluminum hydroxide, Gardner arrived at the same conclusions as Denny, Robson and Irwin, namely, that in experimental animals the development of silicotic changes could be prevented if eithertogether with the silica, or subsequent to its inhalation...

Jan 1, 1946

The problems arising in the excavation of hard rocks with the use of mechanical tools consist chiefly in a slow advance rate accompanied by an intensive wear due to the toughness and abrasiveness of the rock. In order to allow the further extension of mechanical excavation beyond the limits of the presently available technology, the assistance of waterjet aiming at improving the performance of the equipment while reducing the wear rate of the tools, has been recognised as one of the most interesting technical solutions. The paper illustrates the improvement of the performance of both disk cutters and picks obtained with the waterjet assistance at the Waterjet Laboratory of the University of Cagliari on a medium-hard rock.

Dec 6, 2010

By K S. E, S C. Parker, T K. Kundu

Understanding the fundamental principles governing the reactions at surfaces has always been the goal of theoretical surface science. The atomistic simulation techniques have been used to calculate the surface structures and the stability of quartz and wollastonite, and their adsorption behaviour in the presence of molecular and dissociative water, and the two widely used collector head group molecules of methanoic acid and methylamine. The dissolution behaviour of wollastonite has also been modelled. The calculated surface energy, hydration energy and reaction energy values have been examined and discussed in the light of flotation literature. These studies have given an insight into the interactions at atomic level, which indicate that modelling techniques should be capable of predicting the adsorption behaviour and to design the selective collector molecules, which is of central importance to the mineral processing technique of flotation.

Jan 1, 2005

By A Tomsett, J Rutter

Ore control systems at Ridgeway have been designed to deliver gold and copper metal production through focussing on the ore characteristics that impact on mine and mill performance and ultimately metal delivery. This is achieved using data collection and management systems which allow data to be collected digitally with æat captureÆ validation routines. This data forms the basis of forecasting systems which aim to accurately assess local in situ and drawn ore characteristics. Physical attributes of ore such as draw characteristics, brow conditions and visual grade estimation are rountinely recorded. Ore tracking and accounting systems monitor gold and copper grade, copper mineralogy, host lithology and ore sizing. These have material impacts on concentrator throughput and metal recovery. Routine reconcilation and check sampling allow calibration of these systems.

Jan 1, 2002

By D Chalmers

Drill and blast mining techniques are used to mine coal outburst prone and high gas content coals in Australia. As the risk of an outburst is increased in high gas content coal, it is considered that drill and blast is the safest way to mine coals that refuse to yield gas even after considerable gas drainage efforts. The availability of suitable explosives for drill and blast in Australia is dependent on the æBuxtonÆ tests. With the diminished coal operations in England, the type and supply of such explosives is tenuous, causing significant disruption to the production of coal in some mines. In an attempt to free up the availability of explosives a review of the methods used for the testing of coal mine explosives was undertaken to ascertain the scientific basis for these tests. It was hoped that this comparison would allow regulators to have the confidence in explosives that had been tested elsewhere. Although this was not achieved, it has spawned a major research project that aims to better understand the mechanisms involved so that either confirmation of the current testing regime can be achieved or more suitable and scientifically based tests can be adopted. This paper looks at the ongoing research program investigating the parameters that are involved with methane ignitions from explosives. By utilising high-speed data capture and processing the research project is trying to view an ignition as it happens to identify the mechanisms involved so that better explosives can be designed for the coal mining industry.

Jan 1, 2007

In mid-1998 Atlas Copco Rock Drills AB introduced the first member of a new family of drill rigs. This new family, Rocket Boomer L1C/L2C/L3C, is based on modern computer technology and also on what is characterised as information technology. The design of the drill rigs are modularised both in hardware as in the software. This means that the functionality of the drill rigs is upgradable step by step. Added upon the basic drill rig functions are the new options as ABC Regular (known also as Contour Control), ABC Total, drillplan generator and communication products. The main objectives of these functions are to facilitate real quality drilling.

Jan 1, 2003

By Coin CDA

From a study of coke samples obtained from the tuyere level of four Australian Blast Furnaces, the nature of in-furnace coke degradation has been investigated. At the periphery of the raceway is a concentration of fines and the lump coke appears dull and rounded. However coke from the deadman is angular and relatively undegraded. Cokes made from higher rank coal appear to suffer preferential attack of the reactive maceral derived component (binder). The coke from lower rank coal appears to be attacked non-preferentially by the solution-loss reaction. Initial attempts to simulate these phenomena have given results consistent with these findings. From chemical analysis of the tuyere probe samples there appears to be a relative increase in carbon and decrease in-.sulphur and phosphorous between stockline and tuyere level. An overall decrease in coke mineral matter derived material was noted and associated with this was a significant gasification of silicon. Consequent formation of silicon carbide was noted.

Jan 1, 1981

By Kikuta K

ISP (Imperial Smelting Process) produces zinc and lead simultaneously from zinc and lead sulphide concentrates and recovers copper and precious metals into a lead bullion. The strength of sinter is important to keep permeability in the shaft of the Imperial Smleting Furnace. The residual sulphur content of the sinter is also important as it causes metal losses into slag. The paper describes an investigation into the sintering operations to improve sulphur elimination and sinter strength. The micro structure of the sinter and the effect of the blast rate, sintering temperature etc have been studied.

Jan 1, 1993

This paper will discuss specifically the performances of vibrating screens having circular motion with inclined decks and linear motion with horizontal or near horizontal decks and both related mainly to coal, metalliferous, and other granulated solids applications where screening and efficient classification is required. Some misconceptions have been applied in the past with regard to making a screen type selection using either circular throw or linear throw and therefore this paper will endeavour to clarify these misconceptions.

Jan 1, 1984

By B Cronin, M Gao, M F. Young

Fine grinding technology has become extremely important for Mount Isa Mines Limited in the last decade for flowsheet development for the McArthur River deposit and in rejuvenating the Lead-Zinc Concentrator at Mount Isa. Regrinding products with 80 per cent passing seven microns and 12 microns were required, respectively, for the McArthur River ore and the Lead-Zinc Concentrator at Mount Isa. Development of the ISAMILL, a horizontal stirred mill with a gross mill volume of 4000 litres (a net volume of 3000 litres), has been successful in delivering the required grinding product sizes with an energy consumption acceptable to a mining operation. The ISAMILL performance for processing both lead and zinc streams at Mount Isa is discussed in this paper, including the milling energy efficiency, the media wear and the size-by-size recovery data for one flotation process following the fine regrinding stage. The potential use of the ISAMILL technology at various phases of the mining cycle is also discussed.

Jan 1, 1998

Alcoa of Australia's Western Australian bauxite mining operations in the Darling Ranges, south east of Perth, present major challenges in the control of air blast. The close proximity of rural communities and the face profile make the traditional methods of air blast control difficult. An extensive blast noise monitoring programme has been established. The develop- ment of a computerised blast noise prediction model and the establishment of a radiosonde weather balloon facility have reduced blast induced complaints by a factor of ten. The meteorological factors affecting blast noise transmission are discussed and examples are given of adverse weather condit- ions for the south west region of Western Australia.

Jan 1, 1982

By Moy A. D

The Esperanza deposit is located 120 kin N of Mount Isa, Queensland at approximately lat 19¦20'S, long 139¦22'E on the Camooweal (SE 54-13) 1:250 000 scale map sheet. It is one of several structurally controlled copper ¦ cobalt deposits developed along the Mount Gordon Fault zone and related faults, within the Western Fold Belt of the Mount Isa Inlier (Figure 1). Together with the nearby Mammoth orebodies it forms the basis of the Gunpowder operation of Aberfoyle Limited. Until recently ore was mined from the Mammoth orebodies by open stoping with decline haulage to surface leach pads. Leaching of in situ broken ore (in place) and surface heaps, followed by solvent extraction and electro-winning (SX-EW), produced copper metal on-site. In March 1997, mining was suspended at Mammoth and the focus of the Gunpowder operation switched to development of the Esperanza orebody, which is expected to begin open cut production in mid 1998. SX-EW methods will produce 44 000 tpa of copper from an expanded plant. The pre-mining mineral resource at Esperanza (measured, indicated and inferred) is estimated at 4.6 Mt averaging 7.7 per cent copper.

Jan 1, 1997

Every estimate of ore reserves necessarily contains an assumption in regard to the specific gravity of the ore. This assumed figure may be based on experimental data, on textbook data, or on a reconciliation of past tonnage estimates and production figures. Not infrequently it is simply a guess - shrewd or otherwise.Errors in the density factor are not likely to be serious in gold-quartz mines-or, at least, not so serious as in base metal mines. It is to the closer determination of ore density in the latter that this paper is devoted. Moreover, the remarks apply to ores which show no appreciable pore space.Not many ore bodies are sufficiently homogeneous to allow of a truly representative factor being obtained by the simple testing of a few specimens of ore, or by the weighing, after breaking, of a carefully measured block. The empirical figure derived from a comparison of past ore reserves and actual production can never truly describe conditions other than those now past; no real link with ore as yet unmined is provided. The dilution of heavy ore by waste is not exposed by this method, but is effectively cloaked. Anyerrors in past estimations of ore reserves are transmitted, by way of the density factor, as a source of error in all future estimates.ObjectIons may be raised to the practice of weighing measured blocks of ore in the case of any but a very homogeneous ore body. Even then, the exact composition of the block weighed, and an indication of whether its moisture content is representative of the whole, are difficult to determine.

Jan 1, 1940

Three major and two minor uranium deposits 'have been worked by open out mining since the discovery of ,the Rum Jungle field in 1949. Total production has been about 9679000 tons of uranium ore at 7;39 lb U308/ton and 4029000 tons of copper-uranium ore at 6.27 lb U308/ton and 2.7% Cu, with significant tonnages of base'metal ores. The deposits occur in or near black pyritic slates of the Lower Proterozoic Golden Dyke Formation, near the contact with the under- lying Coomalie Dolomite. The mineralization is probably younger than the grahite complexes in the area, and a structural-stratigraphic control of ore deposition is used as a basis for uranium exploration.\

Jan 1, 1968

Faced with rising costs and lower metal prices, several Ontario base metal sulphide mines have changed their method of mining to vertical crater retreat mining. This is a bulk mining method that utilises large diameter holes and mines successive cuts remotely by blasting and cratering the bottom of the drill holes. The orebody is mined from the bottom up. The method in turn has required a change in materials handling to cope with the greatly increased productivity.   This paper presents an overview of vertical crater retreat mining in the Sudbury area using examples from several producing mines. The paper reviews the history of vertical crater retreat mining, various methods of applying vertical crater retreat layouts, the development of in-the-hole drills capable of drilling the large diameter holes required, methods of explosives loading and blasting to achieve the required cratering effect, methods of ground support including backfill placement, and the ore loading equipment presently being utilised including remote control load-haul-dump units and continuous loaders.   The safety aspect of vertical crater retreat mining has been of concern, and was the focus of a provincial inquiry. The benefits in improved safety are demonstrated through an analysis of various records kept by the mines and provincial agencies.   Future trends can now be envisaged, particularly in relation to deep mining. Some experimental work which could have practical applications, is described.

Jan 1, 1989

By McQueen LB

The Water Board has been involved in the development and ipgrading of sewerage facilities in the Blue Mountains since 1980. In 1984 the Board prepared a report that dealt with the Blue Mountains Sewage Effluent Management study. Successive 3ovemments have been concerned about development in the 3lue Mountains and the effect this development is having on the luality of the streams flowing into the Blue Mountains National ?ark (presently up for World Heritage Listing).

Jan 1, 1993

Optimum selection of explosives by means of monitoring explosive performance can lead to increased profitability through the control of fragmentation, a reduction in hangingwall and footwall damage and overall drill and blast costs. Studies conducted at the Mount Lyell Mining and Railway Company underground copper mine evaluated in situ the performance of four explosive types. Measurements included monitoring the levels of induced shock energy and the attenuation thereof with distance. The velocity of detonation (VOD) of these explosives was also measured using in-hole techniques. Assessment of these results, together with a knowledge of the rock mass strength, facilitated the selection of an explosive that was best suited to the given rock mass conditions.

Jan 1, 1995

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 Hoskings AD

Bolting forms a prestressed elastic layer of rock which is capable of supporting loads at right angles to the bolted surface. Investigations on rock bolting made with a number of different models give rise to empirical and theoretical prin- ciples for the formation and action of the layer. In the models, flat and arched layers of many materials were used simulating rock conditions ranging from closely interlocked blocks to fragments of various shapes. Results of observations made in the underground works of the Snowy Mountains Scheme are related to the mode of action of bolted surface layers of rock. There is abundant experimental, theoretical and practical explanation for the well-demonstrated capability of bolting as a means of rock support.

Jan 1, 1971

By N Udugampola, d A. Seneviratne, X Ai, B Li

With the evolution of mining technology, wireless mesh networks using low-power, long-range technologies such as LoRa are increasingly utilised in underground mining operations. Efficient deployment of wireless nodes in such mesh networks necessitates understanding radio wave propagation behaviour in underground mines. While existing propagation models either remain theoretical or apply only to basic geometric shapes, we propose a practical approach to analyse radio wave propagation behaviour in underground mines using ray tracing simulations with reconstructed 3D models of targeted environments. Our method validated using a set of corridors as a substitute for underground mine environments, involves constructing a 3D model using SolidWorks from LiDAR scans of the environment and performing wireless transmission simulations using the MATLAB ray tracing toolkit. Our simulation model is also fine-tuned by calibrating the raytracing parameters based on real-world LoRa transmission experiments in the actual environment corresponding to the 3D model. This method offers a practical solution for optimising wireless node placement in underground mines, facilitating efficient network deployment while reducing the need for extensive physical testing of radio wave transmissions.

Sep 1, 2024