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A mechanised sub-level overhead benching method is used at Cleveland, to produce 22,000 tons per month of ore assaying 0.92% Sn and 0.40% Cu. The ore occurs in a series of vertical lenses which can be mined by open stoping. Levels are developed at 60ft., vertical intervals by jumbos. The ore is silled out and the stope block formed between levels drilled out by long hole drilling. Each row of holes is fired and broken ore within safe reach from the stope brow is mucked out by Wagner ST-5A Scoop Trams. The remaining broken ore is recovered on extraction of the next lower level. Ore is hauled by road to the crusher station from the mine. As mining proceeds below the lowest surface portal a spiral decline will be used for ore haulage and mine servicing.

Jan 1, 1970

Australia has been a major exporter of LPG since production from the Bass Strait fields commenced in 1970. Export levels have been maintained through the seventies, the bulk of material being delivered to Japan. During this period the use of LPG in domestic markets grew only'slowly and demand was largely met by production from refineries with only shortfall supplies being drawn from naturally occurring sources. The domestic demand is forecast to grow significantly during the eighties as the traditional, automotive and petrochemical uses of LPG are expanded. An increasing amount of naturally occurring production will be directed into these markets. Despite this redirection the current level of exports (about 1.5 million tonnes per year) is likely to be maintained through much of the decade ahead as production from the Cooper Basin and the North West Shelf becomes available.

Jan 1, 1982

There are serious problems in forecast- ing accurately and achieving this goal depends on good quality information, correct assumpt- ions and sound analysis. planner. The forecaster must focus attention on a number of key areas of interest. These areas include major economic trends and changing GNP structure, consumption time series, end-use consumption patterns and substitution potential, accurately updating data bases (up to 5 years ahead), random factor estimation and examination of both long term and secondary mine potential. While metal price forecasting has suffered due to recent uncertainties, with increased importance on planning tools and cost analyses, it is still a necessary function. Forecasting is subject to the real world and the metal industry is made up of imperfect markets in a dynamic state. The real world provides the challenge to improve the accuracy of forecasting.

Jan 1, 1983

By A Atkins

Six recent case studies were selected based on the eight main causes of mine disasters (Table 1; Quinlan, 2014) and where credible information sources, such as Royal Commission Reports, Coronial Investigations and textbooks, were available. The six case studies are listed below. Details are available via this link or the conference PowerPoint accompanying this paper. 1. Beaconsfield, Tasmania – 2006 Fall of Ground/Seismic Event (Chandler, 2009; Melick, 2007; Wright, 2012). 2. Bingham Canyon, USA – 2013 Manefay Slide (Ross, 2017). 3. Bronzewing, WA – 2000 Hydraulic Fill Inrush (Hope, 2002). 4. Brumadinho and Samarco, Brazil – 2015 and 2019 Tailings Storage Facility (TSF) failures (Bowker, 2019; Darlington et al, 2019; Demajorovic, Lopes and Santiago, 2019; Morgenstern, 2016). 5. Northparkes, NSW – 1999 Cave Air-blast (Bailey, 2003; Hebblewhite, 2003). 6. Pike River, NZ – 2010 Methane Gas Explosion (Macfie, 2013; Panckhurst, Bell and Henry, 2012.

May 5, 2022

By Barber J

The manganese ore of Groote Eylandt is a shallow sedimentary deposit of Cretaceous age. There are a number of deposits which vary greatly in ore texture, density, percentage of matrix and thickness. The thickness in the present five operating quarries varies from 1-5 metres. The mine output in 1973 was 3 million tonnes of which 60% was blasted, the remainder ripped and bulldozed. The shallow deposit and its varying thickness create rather unique blasting problems which must be overcome in order to produce a minimum overall mining cost but not necessarily resulting in a minimum drilling and blasting cost per tonne. Future planning envisages the introduction of site mixed slurry explosives following test work and the application of a twin boom single operator rotary percussion drill. The paper outlines the overall developments,present and envisaged practices and the reasons for these changes.

Jan 1, 1974

The sulphide ore occurring in the North Mine at Broken Hill is of a complex nature, consisting of an intimate mixture of argentiferous galena, marmatite (zinc-iron sulphide), and gangue minerals. A typical analysis of the ore is:Lead 15.2%Zinc 12.0%Iron 5.3%Manganese 0.8%Copper 0.1%Alumina 0.3%Lime 0.9%Sulphur 11.1%Insoluble 53.8%Carbon dioxide 0.3%Undetermined 0.2%Silver 9 oz. per tonTotal 100.0%The metallurgical practice for the recovery of the lead concentrate and zinc concentrate from the crude ore is briefly described in the following pages.(1) COARSE CRUSHING AND FINE GRINDING OF THE CRUDE OREThe crude ore from the mine, containing lumps to the size of, roughly, 10 in. x 8 in., is tipped over grizzlies with the bars spaced 3 in. apart; the oversize gravitating to a...

Jan 1, 1933

By J Kinal, I Mitchell

Many flotation plants use pH to adjust the pulp chemistry of their system to achieve optimum separation. For example, in a sequential lead/zinc circuit the pH during sphalerite flotation is increased to 10.5 or greater to depress galena and pyrite, thereby improving selectivity for sphalerite. However, maintaining a pulp at a particular pH value does not necessarily provide the operator with an abundance of information regarding the chemistry changes occurring within a plant. This paper provides the reader with a number of pulp chemical observations in several plants, showing that the same trends are noted over time; however, the magnitude of the measured values do change. Further, the changes in magnitude are invariably associated with a change in mineralogy. Thus, is measuring pH enough? Can the Eh, dissolved oxygen and temperature be measured at the industrial scale reliably? And, are these measurements useful?

Jan 1, 2006

By Falbo A, Quarestima S, Cozza C, Barbaro M

A new synthetic reagent of the mercaptobenzoxazole class, 5- methyl-2-mercaptobenzoxazole, has been studied. This reagent exhibits powerful selective collecting action towards copper sulphides present in several complex ores, as demonstrated both by laboratory and pilot plant tests. Industrial production is expected to start in the near future. The way this reagent reacts with pure chalcocite has been studied utilising in situ FTIR techniques, adsorption tests, electrokinetic potential measurements and Hallimond cell flotation tests. The FTIR studies have indicated the nature of the surface phase. Adsorption isotherms obtained by the rest method have revealed the quantitative evolution of surface products, permitting the determination of surface coverage at various reagent concentrations. The electrokinetic potential has been utilised to verify the stability of individual species in diverse concentration ranges. Correlation of the results obtained has provided indications on the chemical interaction of this reagent with the surface and on the surface Arrangement.

Jan 1, 1993

By A Mehrani, F Zamani, A Dehghani

Vibrating screens play an important role in the dry classification circuit of Gol-e-Gohar iron ore processing plant. This circuit was designed to classify the autogenous mill discharge and produce a suitable feed, with K80 about 450 ¦m, for dry magnetic separators. Three parallel vibrating screens produce more than 50 per cent of the separatorÆs feed. The efficiency of the magnetic separator is greatly affected by feed size distribution. In this work, the JKSimMet 5.1 software was used as an analysing tool to assess the flow rates and USIM PAC3 software as the simulation tool to control and optimise the vibrating screens. Samples were collected and the circuit was mass balanced. Then the vibrating screen was simulated and adjustment parameters such as cut-point, bypass and imperfection factor were determined. The product streams of vibrating screens can also be predicted.

Jan 1, 2007

By K Smith

This paper presents an assessment of the Robertson (2010a) method within the CPTu inversion parameter framework of Been et al. (1987), using CPTu calibration chamber data presented by Jefferies and Been (2015) and in other literature to assess the validity of the method, with particular focus on applicability of the method to TSFs (i.e. its applicability to loose silts and silty sands). The assessment demonstrates that although the method estimates values of k consistent with calibration chamber data, the method estimates values of m that are generally 1.5 to 2 times greater than calibration chamber data. As a result of this, the method generally overestimates Ψ for values of Ψ less than 0, and underestimates Ψ for values of Ψ greater than 0. This may result in both overly conservative assessment of materials as potentially liquefiable and unconservative predictions of material behaviour for loose materials.

Jul 1, 2021

By Ueki S

Underground coal gasification (UCG) is a promising process for obtai- ning energy from coal, which is either unmineable with current mining techno- logy or uneconomic to recover, using conventional methods, in the present energy market situation. There are several coal fields, which could become new coal reserves, if the UCG process were successfully applied. In the 1960's Japanese researchers made a number of basic studies and field tests into UCG, although not all of them produced favourable results. This paper reviews Japanese research on UCG. This includs basic studies into coal gasification using a small, tube reactor fed by air and oxygen, and also large scale model stu- dies(reactor size of 8.Om x 2.4m x 1.5 m). Field test results from Akabira colliery in Hokkaido and a feasibility study of power generation using UCG from a coal field in Hokkaido are also Presented.

Jan 1, 1987

The City of KalgoorlieBoulder is situated approximately 600 kilometres to the east of Perth, and as the major regional centre of the Eastern Goldfields, supporting a population of approximately 25 000. The formation of Kalgoorlie Consolidated Gold Mines in 1989 brought the existing operating entities adjacent to the city under common ownership and management. The Joint Venturers forming the management company are Homestake Gold of Australia and Gold Mines of Kalgoorlie (a Normandy/Poseidon company).This traditional underground mining centre has been worked since 1893, yielding 40.5 million ounces of gold ore with an average head grade of TEN grams per tonne. Historically the heart of the operation has been the famous Golden We located on the Eastern perimeter of the city, in the area known as Fimiston. The other significant operations that form KCGM are the Mt Percy Open Pit and the Mt Charlotte Underground Operation.

Jan 1, 1992

The character of alluvial gold deposits presents severe difficulties, and sometimes limitations, on the extent to which metallurgical efficiency can be measured. Very little monitoring of metallurgical performance is practised. An indication of performance is often extracted from the comparison of production to the estimate. This is a dubious practice. The recovery efficiency of conventional practices, viz sluices, tables and jigs, falls off sharply below 0.2 mm. Field evaluation procedures tend to simulate these conventional practices. Thus the presence of fine gold may not be detected, particularly if obscured by clay. There is increasing evidence that fine gold could, in places, be present in sufficient concentrations to be economic. Most gold in paleoplacers is finer than 0.1 mm. There are established practices elsewhere in the mineral industry that may physically recover gold down to 5 microns in size and which could find application for fine alluvial gold.

Jan 1, 1984

By S O. Hille

Modern remote mining operations in Australia are more commonly trending towards fly-in/fly-out (FIFO) sites. This trend is driven by numerous factors including increased business centralisation, reduction in operating costs, and a desire to live in coastal cities that offer closer family networks and a greater diversity of facilities. Consequently, the resource development industry has had to adapt. When WMCÆs Mount Keith Nickel Operation commenced operations in 1994, it was developed as FIFO for its entire workforce. Since then, there have been several permutations of rosters within a 21 day compressed work cycle including the 14/7 cycle. This paper discusses a case study of the change in management process to the 9/5 work cycle focusing on minimising fatigue in the workplace. It includes the discussion of the business case, employee reaction and the practical application. The impact of the best practice change after 18 months is discussed.

Jan 1, 2002

By Cliff D, Harrison P. Hester C

During 1997 two different types of coal mine inertisation equipment were trialed in separate underground coal mines in Queensland.In April 1997 tests of the Polish developed GAG-3A inert gas generator were carried out at the Collinsville No 2 Coal Mine. These demonstrations indicated that the GAG-3A device was applicable in underground coal mines and that with respect to inertisation rate the device outperformed all other currently available techniques. The unit was assembled rapidly and operated safely during surface and underground trials and no mechanical problems were encountered with the device. The GAG-3A is not suitable for every fire scenario particularly if large volumes of fresh air are being drawn into the mine(where multiple units may be required), but with respect to the selection criteria developed by the Moura Implementation Process Task Group 5 criteria, the unit performed up to the specifications required.

Jan 1, 1998

Chlorine as a lixiviant for gold possesses a number of significant chemical and Idnetic advantages over cyanide but because of its corrosive and vaporous nature the method of implementation needs to be significantly modified. At comparable reagent concentrations the dissolution rate for gold in the C12/Cl- systems is some 10 - 100 times that achieved in the 02/CN system. The dissolution rate in the chlorine system is largely a function of the concentration of C12, Cl- and pH. Under conditions of low Cl', (less than 50 g/1), the dissolution rate begins to drop off dramatically over the pH range from 3 - 4. Increasing the level of dissolved chloride ions shifts the pH of this rate reduction to around pH 5 at 100 g/l NaCl, and to around pH 6 at 300 g/l NaCl.

Jan 1, 1991

By Bhattacharyya A. K

The current methods for predicting pillar strengths are reviewed. A two-dimensional model, based on the Mohr-Coulomb failure criterion, is proposed for determining the compressive strength across the width of a long pillar. The model can be used to determine pillar strength and the depth of the crushed (ie yielding) zone from the pillar edges. The values of the parameters in the model, namely the cohesion and internal friction angle of the coal seam, friction angles at the contact of the coal seam with the roof and floor are determined by matching the strengths predicted by this model with the Bieniawski pillar strength formula for pillar width to height ratios up to 5. It is found that the derived values of these parameters are quite close to the results from laboratory tests. Based on the model, a preliminary analysis of pillar stability is made.

Jan 1, 1995

By Daoust G, Dubois JF

The optimal sequence of decisions on rates of production and cutoff grades is obtained by a dynamic programming model. The main parameters are : 1. the size of the deposit, average grades and grade distributions, 2. the operating costs of mining and concentration, 3. the investments in mine and mill, 4. the smelter charge, 5. the price(s) of the metal, 6. the recovery and the grade of the concentrate, 7. the rate of interest, 8. the taxation formulae, 9. the upper limit to rate and the rate interval and 10. the upper and lower limits to cutoff and the cutoff interval. An amount of ore can be mined at various rates while applying various cutoff grades. It is assumed that a decision to mine at a certain rate during a period conducts to a certain state regardless of the cutoff grade. This assumption which is valid for several

Jan 1, 1977

By White A, Price G

The main assets of a mining company are its orebodies; the second are the people who find and use them.The graphs in Figure 1 were derived from a paper by Rob Macdonald of Rothschild Australia presented to The AusIMM Centenary Conference in Adelaide earlier this year. They show that the value of the industry on the Australian Stock Exchange halved over the past decade, despite the re-investment of capital equivalent to its full market capitalisation. Why is this so? The average dividend yields for the ASX Mining Index was never above five per cent during that period and barely averaged 2.5 per cent. Why then is $Ai million capital re-investment per employee since 1960 not enough to generate a rate of return to investors better than lousy bank interest? Do the investing public no longer regard our industry's assets to be world class?

Jan 1, 1993

By Scott B. R

Bougainville's copper mine is located on the west slope of the Crown Prince Range on Bougainville. A high grade copper concentrate is produced for sale to overseas customers. Production planning which was originally based on pilot plant data has developed progressively since commissioning of the concentrator in 1972. Pilot plant data and mine sampling have been supplanted by the correlation of concentrator performance with ore sources, as the basis for short term planning. The influence of accurate sampling is reflected in 1. hourly shift control, 2. the daily milling statement, 3. the prediction of the characteristics of ore from various mine locations, 4. production reconciliation, and 5. the control of copper losses. The mechanical and electrical failures of the original sampling system emphasized the need for a reliable, automatic sampling facility. The development of a pneumatic drive mechanism, which has now been fully field tested, was undertaken.

Jan 1, 1976