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Up to 19 chemical parameters were studied in flotation pulps in six Australian lead-zinc concentrators with the aim of obtaining a better understanding of the nature of, and changes in, the chemical environment. This paperdiscusses pH, redox potential, and oxygen concentrations, which were all measured continuously.Two plants operated at natural pH in slightly acid circuit and one at natural pH in alkaline circuit, and pH was stable at all these plants. In two plants varying amounts of cement fill were present in mill feed and pHwas variable. At the other plant pH was controlled with soda ash and lime.Redox potentials became more positive as the pulp passed through the plant. The minimum change was 20 mV and the maximum about 250 mV. Potentials tended to be variable at any point early in the circuit, but were more stable later on. In some plants reagent additions had no noticeable effect on redox potentials. However in the two plants operating in acid circuit the redox potential of .zinc rougher feed was markedly affected by changes in copper sulphate addition rate. Sodium sulphite additions had an effect at other plants.Oxygen concentrations in grinding circuits tended to be low (30 per cent of saturation) and very variable. Flotation was usually conducted in pulps at least 90 per cent saturated with oxygen. Addition of sodium sulphite had a marked effect on oxygen content in one plant, but less effect in two others.Statistically significant relationships were found in some plants between pH and redox potential, redox potential and oxygen saturation, and oxygen saturation and pH.Improved control of copper sulphate and sodium sulphite additions could result from applications of this work.

Jan 1, 1970

This paper summarizes the progress of geological exploration at North Broken Hill Ltd.The North Mine orebodies occur in knots of minor folds on a simple limb structure which is itself highly folded, giving rise to two distinct orebodies pitching N. at av. 42° down to 2,920-ft. level, where the pitch steepens to near vertical as a result of complementary shear movement on the Globe-Vauxhall Crush Zone.The lack of adequate marker beds and top and bottom relations makes the resolving of the complex structural environment of the orebodies most difficult.To test the deeper ground of each side of the De Bavay Fault on the 2,600-ft. level the footwall drive was extended 3,556 feet and over 20,000 ft. of drilling completed from three transverse fans, only one of which intersected the orebodies due to steepening of pitch.The problem of locating the North Mine orebodies N. of the DeBavay Fault remains speculative because the exact position of them S. of the fault is still unknown. Exploration beyond the fault in the search for ore had two lines of mineralization to consider, an eastern one through Cosgroves-Round Hill, long regarded as the continuation of the main lode, and a western one passing through Silver Hill Silver Peak.From surface 45,000 ft. of drilling was completed in five sections, establishing that the structure was dominantly synclinal with a flatdipping E. limb, the W. limb and adjoining structures being involved in the Globe-Vauxhall Crush Zone. Mineralization, though weak, was remarkably persistent but the economic mineralization exposed at surface has not persisted with any continuity.Deep exploratory drilling below the bottom level (3,370 ft.) has established high-grade ore to a depth of 4,095 ft. and also has proved its existence within the Globe-Vauxhall Crush Zone.INTRODUCTIONThis paper summarizes the progress of geological exploration at North Broken Hill Limited from the inception of the Geological Department in 1941 until the end of 1955. The writer has drawn freely on departmental records for the period prior to 1947.

Jan 1, 1956

The AusIMM/AMIC code for reporting Reserves seeks to improve the calibre of professional reporting on this subject. But have they gone far enough? Should the code appreciate that the degree of reliability of estimates required will vary with the type of mining planned? How does one "confirm continuity" as required by the code? The aim of optimum development drilling is to achieve appropriate ore zone definition for acceptable estimates of reserves and their economic extraction. Can this procedure be in conflict with the code? How does it affect finance decisions?

Jan 1, 1989

Judicious placement of a range of geotechnical instruments was employed at the Tasmania gold mine, Beaconsfield, Tasmania, as a key strategy in the monitoring of rock mass conditions over the past four years. The range of instruments employed included vibrating wire stress-meters and hollow inclusion cells to monitor changing stress conditions, resistance wire and multipoint borehole extensometers to monitor the impact of stress changes on the integrity of the rock mass, and instrumented cable bolts and threadbar bolts to monitor the static and dynamic impact of rock mass changes on the installed ground control system. Initially the monitoring was of a qualitative nature, monitoring change from the time of installation. The value of the output was considerable when considered in relation to the ongoing seismic record which was also being monitored. It was clear from the seismic record and the monitoring results that stope blasting was the primary trigger for changing rock mass conditions. However, it was unclear how well observed behaviour was reflecting conditions anticipated by elastic numerical modelling. The latter had predicted significant stress increase in the near field of man-access footwall development. Qualitative monitoring and visual inspection did not support the modelling prediction, and this led to a program of quantitative measurement being undertaken. Measurement of the absolute stress condition in the backs of footwall development immediately adjacent to monitoring hollow inclusion cells provided the benchmark for tracking quantitative stress change. The program provided insight into the evolution of principal stress field magnitude and orientation in relation to rock mass change observed with extensometers and instrumented ground control elements, as well as providing a degree of calibration between the elastic numerical modelling and the virgin stress field. Calibrated monitoring data has also provided a useful benchmark for finite element modelling which is to be used for future mine-wide design.

Nov 25, 2010

By F N. Baez

This paper supplements a keynote address prepared for the MassMin 2016 conference on mass underground mining methods, including block, panel, inclined and sublevel caving. It advocates for a new cave mining paradigm that takes advantage of a number of new and disruptive technologies or innovations that have evolved over the last 15 years, some of which were initiated by major mining companies such as Codelco. The paper will address the challenges that the industry will be facing in the future as well as possible solutions. As background, the paper summarises the challenges that the industry has faced in the past and how such challenges were addressed. The author acknowledges that given his more than 30 years of experience with Codelco Chile (operations and corporate), aspects of his intelligent mining concept have no doubt been influenced and have matured during his invaluable time with Codelco also as the Head of Technology and Innovation. In the paper, he uses some of the innovations developed within Codelco and by the Chilean Government to illustrate the concept of ‘intelligent mining’.CITATION:Baez, F N, 2016. ‘Intelligent mining’ – the way of the future, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

When the Mining Bill came before the Victorian Legislature not so many months ago, the question arose whether mining managers required education, and to what extent. Some members of the House expressed themselves in a way which appeared to leave the impression that mining managers would be all the better if they were not brought up in a scientific school.To try and prove what we owe to science I will give a short history of colonial mining from the earlier period to the present time and compare results.I believe I am right in saying that South Australia is the pioneer colony in mining and to her belongs the credit of not dnly being the first mining colony, but also that her beginning turned out so successful, as the history of the Burra Burra copper mine will testify. At about the same time a little galena mining was carried on nearer to Adelaide, but as this did not prove a success and was only worked by tributing parties, little notice was taken of it.

To many Australian Mining Engineers, we take it, the singular features of banket deposits are not as familiarly known as they would wish, possibly because in the majority of instances they are not in touch with the South African milling world, and have had little opportunity of studying the development of the banket beds, either from correspondence or literature. The writer hazards this opinion feelingly, because, when in Australia and before he had visited Africa, the utmost knowledge he was able to obtnin was a mass of conflicting theoretic discussion as to the agencies which formed the banket bed, without any practical hints as to their geological horizon, the rocks with which they are associated, the usual appearance and character of the ore, in fine, without that everyday detailed description which the miner requires when seeking information regarding mineral or metal deposit foreign in character to any that he has yet studied, or as yet had any opportunity of studying in his own country.The writer recognised that many more able men than he have from time to time discussed the features and formation of the banket beds of the land, notwithstanding which and feeling that many of his Australian colleagues have found themselves in a similar position regarding accurate detailed information respecting these African banket deposits as he himself was, he hopes that the present paper on the said deposits, as found on the fields under notice, will prove useful to some and of interest to all.

By Mech B

This paper gives a general description of mining practice at The Zinc Corporation Ltd., Broken Hill, New South Wales.The basic mining methods are those which have been common in Broken Hill for many years and have been well described in previous Proceedings. The main object of this paper is to indicate developments which have occurred in recent years and to describe changes in layout, mining methods and equipment which are taking place at present.The following headings have been adopted: History Geology and general characteristics of the orebodies, Geology, The lead lode, The zinc lode, General characteristics, Ore reserves, General mining method, Exploration and diamond drilling, Shafts and shaft sinking, Main shaft, Old main shaft, Block 5 shaft, New upcast airway, Development, Level interval, Level layout, Driving and crosscutting, Winzing, Rising, and Stope preparation.

Jan 1, 1946

THOUGH the literature on the chamber process is considerable, it mostly refers to European conditions. Owing to the demand for acid for flotation and leaching at the mine, it may be necessary to work the process under other conditions. Consequently, some results obtained during the chlorination days at Mount Morgan, within the Tropic of Capricorn, may be useful for reference when working in a similar climate. Though the chambers must be protected against tropical storms, thorough ventilation should be provided, with plenty of space between the chambers, which are almost invariably crowded together. Not only does the space assist in the cooling of the chambers, but it is very desirable during repairs, when lead andtimber have to be hoisted up. The connecting flues between the chambers, which are fairly efficient mixers and condensers, should be round, supported from above, and with the least possible timber about them. Their position and arrangement deserve careful attention. Lattice work will be sufficient protection for the sides of the chambers, and the roof should be high and well ventilated. The Mount Morgan plant, crowded and not well situated, consisted of seven chambers (four over 50 ft. in length), one Glover tower 7 ft. 2 in sq. x 20 ft. high, one Gay Lussac 9 ft. sq. x 30 ft. higb, also one 5 ft. diam. x 25 ft. high. There was one pipe column 4: ft. sq. x 14 ft. 6 in. high. The chambers were run as one unit, and were much lower than those usually constructed in Europe-less than 15 ft. high. Provided that suitable timber can be obtained, 20 ft. is quite low enough. It should be quite satisfactory to use round poles for the studs, and so admit more air space between studs andlead.

Jan 1, 1920

The process of electrostatic separation was developed in the late 19th century, but did not make much headway for about 25 years. High dc voltages, of the order of 20 kilovolts, are involved, and the only means of obtaining such voltages at that time were by the use of frictional machines, such as the Wimshurst. These were not reliable, for two reasons:-a. If a spark discharge occurred it took an appreciable time before a steady voltage was again attained.b. In damp weather the machines were almost useless.In the first 20 years of the 20th century the advent of mechanical and vacuum-tube rectifiers led to promising developments of 'the process. In the early 1920's flotation became widely used commercially, and proved to be more reliable, and capable of wider application, than electrostatic separation. During the last 15 years or so, with a better knowledge of the fundamentals forming the basis of the process, electrostatic separation is beginning to compete with flotation, especially in the treatment of smallsizedgranular material, such as beach sands. Electrostatic separation can be, and is, widely used in many cases where flotation is impossible, such as in the cleaning of food products which must be kept dry.

Jan 1, 1950

The mining industry is the largest source of foreign income for South Africa. It is also the main source of employment in the country and, as an industry; it is also one of the largest. Due to the labour-intensive nature of the industry, labour costs in South African mines make up nearly 50 per cent of the total mine cost. It is thus imperative to have optimum labour planning and labour management systems in place.The focus of this study was to investigate current underground labour-planning models. It is shown that there are serious limitations. The range between an oversupply and undersupply of labour can be as high as ten per cent. A new system was therefore developed to ensure a constant labour demand and supply on a daily basis. One of the main objectives was to determine the existing labour supply range and thus the requirements to fill the undersupply. For this purpose, a specific methodology was designed to capture and process all the relevant information. Mine personnel was involved throughout the entire process to ensure ownership of the new model. This buy-in was achieved through planning workshops, interactive presentations and discussions. The improved frequency of daily blasts validated the new system by providing the correct amount and mix of the labour force. The new labour-planning model was then extended to optimise revenue. Implementation on a mine resulted in increased income of R95 million.

Dec 6, 2010

By D Craw, C E. Martin, C Smith, C Rufaut

Wangaloa Coal Mine opened in 1945, and by the time of its closure in 1989, had produced 750 000 tonnes of coal and disturbed an area of 75 ha. The original mining licence required land rehabilitation to exotic forestry, however the current owner, Solid Energy, has worked with Crown Minerals and local councils to write a new rehabilitation objective. The site is now being stabilised and replanted with native species, and may be available for public use before the coal mining licence expires in 2007. Site discharge permits expire in 2017, and by that time, it is anticipated that discharge water chemistry will be similar to background levels. MWH are currently contracted for management of the mine rehabilitation project. The Kaitangata coal unit mined at Wangaloa is sulfurous lignite with associated pyrite. Kaitangata coal contains 3.2 wt per cent sulfur, which is higher than most New Zealand coals. Initial analyses at Wangaloa indicate low pH (2.56.2) values in soil, groundwater and surface waters as a result of acid rock drainage (ARD) processes, leading to increased metal mobility and challenging conditions for vegetation. Pilot studies indicate pinus radiata needles contain up to 67 mg/kg boron, and elevated As, Cu and Zn concentrations in surface waters. The main lake at the site has a pH of approximately 4.9, despite lime dosage in 2002. There is a real need for a complete geochemical model of the Wangaloa coal mine. Such a model could be applied to similar restoration projects, and would assist by pinpointing geochemical processes and toxic metal relationships most harmful to the receiving environments. Using this model, rehabilitation in the future will be targeted and more efficient. This project is part of a larger scheme to characterise and model the Wangaloa mine site restoration, including waters, soil, vegetation, geology and invertebrates.

Jan 1, 2003

By M J. Begbie, K B. Sporle

The Golden Cross low sulfidation epithermal deposit produced approximately 750,000 ounces of Au from two ore zones: the underground Empire Vein System and the open pit stockwork. The Empire Vein System has at least eight stages of vein formation: (1) sulfide veins, (2) black veins, (3) massive veins, (4) banded veins, (5) thin white veins, (6) crumbly veins, (7) massive/platy calcite veins, and (8) flattened rhomb calcite veins. Gold mineralisation occurred relatively early in the lifetime of the system, dominantly during 2 through 4. The late calcite veins (7 and 8) and early sulfide veins (1) are barren. The vein system formed in a dominantly extensional environment, though some compressional faulting may have also existed during vein formation. There is no evidence for significant strike-slip faulting during vein formation, highlighting the fact that explorationists should pursue on-site structural patterns rather than fashionable models.

Jan 1, 1998

Upon cessation of mining activity open-cast mine pits typically fill with water, forming a æpit-lakeÆ. The water in these lakes, in some instances, contains high concentrations of ædeleteriousÆ material. Containment and/or dilution typically requires an understanding of how stratification in the pit-lake will develop over a long timescale (say 100 years). Vastly different transport rates can develop due to differing hydrogeochemistry, basin morphology and climate. Numerical (computer) modelling is the most likely approach for successful prediction over long times. While lake modelling tools are available, useful numerical modelling requires improved understanding of transport in such systems because they are different to natural lakes in a number of ways. Notwithstanding the effort required to improve our understanding, the modelling provide a means of testing approaches to active management of pit-lakes.

Jan 1, 2002

By Hookings H. J

UNDER a contract relating to the sale of a Broken Hill concentrate, the differentiation between granular and slime concentrate is determined by the proportion of the material which will pass a 200-mesh (I.M.M. standard) screen, and this has led to considerable attention being devoted to the question of laboratory sizing tests with screens of this order.It was found that many of the screens turned out by the makers during the war, and also since its termination, did not conform with the I.M.M. specifications as closely as some supplied in pre-war days. A perfect screen is hardly to be expected, but when the above contract was framed the parties anticipated that, by special care being taken during manufacture, a screen at least as good as the best pre-war screens would be available. This, however, has not proved to be the case, and the large irregularities in screens recently supplied render them useless for sizing determinations under the contract. The makers were approached through the Institution of Mining and Metallurgy, London, with the view of obtaining a few screens conforming as closely as possible to the 200-mesh I.M.M. standard, and in response to a request twelve pieces of screen were...

Jan 1, 1922

The maximum current density at which conventional copper electrowinning plants will result in satisfactory, adherent, and dendrite·free cathodes is determined by the thickness of the diffusion boundary layer. A decrease in the value of that thickness will permit an increase in the current density. This fact is utilized to develop a high current density cell in which the reduction of the boundary layer thickness is accomplished by means of a specially designed electrolyte circulation system. The high current density cell is used to determine the effect of current density on such process parameters as current efficiency, cell voltage, power consumption, and cathode purity. A number of empirical equations are developed for the purpose of estimating the magnitude of these effects.

Jan 1, 1972

The history of zinc production in Australia is outlined including attempts to make zinc electrolytically at Cockle Creek, N.S.W. in the last century, the use of horizontal retorts at Cockle Creek and Port Pirie, South Australia, production by electrolysis at Risdon, Tasmania and at Port Pirie using zinc oxide fumed from lead blast furnace slag and production by the Imperial Smelting process at Cockle Creek. Developments in the electrolytic process are described including those in roasting, acid manufacture, leaching, purification, electrolysis, melting and casting. The Imperial Smelting process technology is also outlined. In both processes global technology is reviewed, including important Australian contributions.

Jan 1, 1986

By Woodcock J. T, Jackson N

Wattle Gully Gold Mines N.L. of Chewton, Victoria, has decided to replace its present battery plant by a new mill to treat a free milling gold ore, after fine grinding, by concentrating coarse gold in a jig concentrate for amalgamation, and fine free gold and auriferous sulphides in a flotation concentrate for cyanidation. This paper outlines the economic justification and advantages of this step. In a review of the present position at the mine, a history of the company is followed by a description of the ore and its occurrence.Present treatment practice in two separate battery plants is described. Treatment tailings assay 1 dwt/ton gold and a substantial part of this gold is finer than 200 mesh.Experimental work showing how recovery may be improved is discussed and alternative methods of concentrating coarse gold mentioned. It is decided that the most suitable method for recovering gold from the ore is by jig concentration plus flotation.The merits of various flowsheets incorporating these techniques in the existing plant and in a new plant are assessed. It is concluded that there is no advantage in extending or converting the existing two battery plants, and it would be more economical and satisfactory to build a new plant.An economic study shows that for a capital expenditure of £120,000 a new plant could be erected to treat 70,000 tons p.a., working a 5-day week, and return an additional 14.2/- per ton, or £50,000 p.a., in revenue over the existing plant. It is estimated the plant cost can therefore be recouped out of savings inside three years. Probable ore reserves are sufficient to cover this period and additional ore will certainly be developed.INTRODUCTIQNSince 1934, Wattle Gully Gold Mines N.L. has been mining a lode gold ore at Chewton, near Castleniaine, and treating it by stamp milling and plate amalgamation, plus table concentration of auriferous sulphides. In 1954, following two years of unprofitable operation, a rehabilitation programme of all sections of the mine and plant was commenced. In the treatment section, two, major prospects for improvement...

Jan 1, 1959

By Edwards A. B

Renison Bell is on the Emu Bay Railway, midway between Zeehan and Rosebery on the west coast of Tasmania. The tin deposits in this area have been described by G. A. WaIler (1902), L. K. Ward (1909), H. Hermani (1914), and Hartwell Conder (1918), for the Tasmanian Geological Survey. The ore-bodies occur in the slates, grits, altered lava flows and tufts of the Dundas Series, and consist of fine-grained cassiterite disseminated through massive sulphides (chiefly pyrrhotite or pyrite), or through bodies of quartz and sulphides. Some of these bodies show a N.W.-S.E. strike, parallel to the strike of the tin belt, but others strike N.E.-S;W. or E.-W.The ore-bodies are of two types: (1) steeply dipping fissure veins,' spoken of locally as "feeders," and (2) flatter-lying bodies more or less conformable with the bedding planes of the slates (bedded veins), spoken of locally as "floors."The feeders range from 5-12 ft. in width, with occasional bulges as great as 4q ft. Their lengths vary from 100 ft. to several hundred yards, and they are known to continue to Clmsiderable depths. 'They dip steeply, generally at angles of 45° to 60° to the east or south.The floors, where they occur, 'are directly connected with the feeders, and are sheet-iike bodies of sulphide ore. The composite ore-bodies thus have the shape of an inverted L, or a T, according to whether 'the floor extends out from one side or both sides of the feeder. Most of the floors extend from the hanging-wall side of the feeder. Where erosion has removed the connection, they appear as separate bodies.The feeders as a rule carry more quartz and arsenopyrite than the floors, and are richer in tin. In addition, the cassiterite tends to be coarser grained in the feeders than in the floors. The floors, on the other hand, carry a greater proportion of -sulphides, chiefly pyrrhotite, and the grade of ore and grain size of the cas,siterite tend to decrease as the floor is followed down the dip away from the feeder, so that the outer and lower extremities of the floors may be too low-grade to work economically. The average grade of the ore worked at present is 0·9,0/0 tin. The slates forming the roofs of the floors are commonly much contorted and silicified,' so that they form hard rocks in which the contortion and shattering of the original slates are well preserved. Joints extending upwards, more or less at right angles to the roof of the floor, are occasionally filled with finely crystalline quartz, similar to that in the orebodies, and are often rich in tin, so much so that the slate as a whole may average 0·4% tin.Some carbonate gangue is present in all of the ore-bodies, commonly on the footwall side, and, in places it becomes an important constituent...

Jan 1, 1943

Titanium and Zirconium Industries Pty. Ltd. separates rutile and zircon from heavy mineral concentrate recovered from sand dunes on the east coast of North Stradbroke Island, Queensland. Separation plant feed is delivered to Dunwich, on the west coast, by a seven mile aerial ropeway traversing the island. Mining and concentration is effected by two floating dredge-concentrators now operating on the beach 31; miles from the aerial ropeway terminal. Heavy mineral concentrate is transported hydraulically from the dredges to the ropeway through a 6 in. pipeline. Six pumps in series deliver 24 ton/hr of dry solids in a pulp containing 13 per cent solids. For maximum economy the transfer pumping system is controlled deliberately to cause transportation in the zone of incipient settlement of solids, ieat velocities below the limit deposit velocity for the particular pipe diameter, pulp density, and specific gravity of solids. Automatic density control, based on a combination of power consumption and pipeline pressure, eliminates the danger of plugging the line but periodic flushing is necessary to remove gradual accumulation of solids in the bottom of the pipe. After 15 months operation the pipeline was descaled with hydrochloric acid to remove severe blistering with rust nodules, regrowth of which is now prevented by continuous injection of inhibitors. After transporting 100,000 tons of heavy mineral the average wear on the steel portion of the pipeline was 0·01 in. and indications are that wear on the asbestos cement portion is less.DESCRIPTION OF OPERATIONSGeographyTitanium & Zirconium Industries Pty. Ltd. (T.A.Z.I.) operates on North Stradbroke Island, some 30 miles southeast of Brisbane, Queensland. The island is approximately 25 miles long and eight miles wide, and is bounded on the east by the Pacific Ocean and on the west by Moreton Bay (Fig. 1). With the exception of a small outcrop of volcanic 1. Manuscript received at The Institute. 8th May. 1962. This paper was presented at the Annual Conference of The Institute. 5th-11th August. 1962.

Jan 1, 1962