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The sulphide ores of the Kalgoorlie goldfield have long been looked upon as' refractory, involving special metallurgical treatment. For many years two kinds of treatment have been practised-(l) wet treatment, including fine grinding, amalgamation or concentration of the free gold, concentration of the sulphide minerals with subsequent roasting and cyanidation, and cyanidation or bromo-cyanidation of the residue from the concentrating operation; (2) dry-crushing of the ore and roasting the whole of thecrushed ore, amalgamation of the gold in the calcine during fine grading, followed by cyanidation. The wet treatment was advanced a stage further when, in 1929, the Lake View and Star Ltd. adopted large scale flotation. As a consequence, however, further metallurgical problems were introduced. This paper covers the investigation, ,of one of the most prominent of these problems.Flotation preceded by strakes was satisfactory to a point.The flotation concentrate consisted largely of auriferous pyrite and tellurides, and the gangue minerals in the concentrate were practically barren.Several sources of loss of gold values were, however, found to be associated with this circuit, viz.-(a) There was the loss of gold in the flotation tailing.(b) Loss by dusting during roasting of the flotation concentrate.(c) Loss of gold in the cyanided residue.

Jan 1, 1937

By Aziz N

The objective of the paper is to develop an understanding of the influence of caving on powered support rating by examining the geology and support performance at two sites which represent the current extremes in support rating, ie 6/240 Ton supports operating in the Hirst Seam at Solsgirth Colliery, Scotland, and 4/900 Tonne supports operating in the Bulli Seam, West Cliff Colliery, Australia. A conceptual model is introduced which considers the coal ahead of the face, the powered support, and the caved waste to be three yielding foundations which interact to control the subsidence of the roof strata. Different caving mechanisms are identified for the strata of the Hirst and Bulli Seams, ihese mechanisms being related to rock properties, ie to the palaeogeography and depositional conditions at each site, producing caved wastes with different yield characteristics. The results obtained for convergence and support reaction during production cycles at both sites are analysed to show the manner in which support reaction is developed, indicating the importance of high setting load densities in the Bulli Seam. Evaluation of the work done on the subsiding roof strata during typical production cycles by two of the yielding foundations, ie the powered support and the caved waste immediately behind the powered support, is used to further demonstrate the influence of caving mechanisms on support rating.

Jan 1, 1986

By Wright R. J

The Commission called tenders for a four boom hydraulic jumbo, plus basket, on an art- iculated carrier in Sept. 1977. Atlas Copco submitted the successful tender in Jan. 1978 for the supply of a three boom jumbo, plus basket. The Promec TH470 jumbo was commiss- ioned in the 2000 m long Sophia tunnel in Nov. 1978. Adequate spare parts were not available during the first three months of operation and the hammers could not be overhauled at the recommended interval. One hammer was removed after drilling 13 600 m due to a crack in the intermediate housing. Tests were conducted with different types of drilling consumables. Both rope and Hi-teed threads were tested and found compar- able. The average penetration rate in the granite was 1.1 m/min. Initially the drillers were not experienced enough to operate the BUT 15ERH booms without causing damage to the booms and hoses. Drilling deviation espec- ially of the perimeter holes was greater than expected. It is now obvious that greater attention must be given to attracting, train- ing and retaining the right type of operator and maintenance fitter.

Jan 1, 1981

By Sewell L. G, White H. S

OWING to two large falls of ground which resulted in serious accidents occurring towards the end of 1908, it became evident that the "open chamber" system then in use was unsuitable for the conditions existing in the Mount Morgan mine. It will be admitted that in all mining operations the first consideration is the economy of the system adopted, combined with its safety and ability to give the desired output. A sectional system with square sets has been introduced into the mine, in which due attention has been paid to these factors. In this paper a brief description of this system will be given. An outline of those previously used will be included, as it is necessary to understand the conditions which existed in the mine at the initiation of the sectional system. Outside the actual mining methods employed, various points that might prove of interest will be touched on.The square set system of mining has been in use throughout, the stopes in the gold ore in the upper levels of the mine since underground operations were started in Mount Morgan. In the oxidized zone the ore was of a friable nature, and in some cases rImning ground was encountered. In the lower levels the ground became heavier, and although the stopes were for the most part long, wide, high, and irregular, and not sectionalized, no difficulty was experienced in winning the ore, and no accident of a serious...

Jan 1, 1911

By M Clay, J Dunlop

Thermal and metallurgical coal mining in Queensland has resulted in mines which contain voids due to open cut mining. While there are several proposals for greenfield coalmines or expansions to existing operations, many existing open cut coalmines are reaching maturity and most will leave one or more residual voids in place. The rehabilitation of mine voids is challenging. Water held in voids will evaporate over time leaving solutes to concentrate. This is likely to lead to poor water quality with limited practical use. The most basic practices to rehabilitate voids have historically involved stabilising the high and low walls, bunding to provide flood protection, and preventing public access. Regulatory reforms for mine rehabilitation were introduced in Queensland as part of the Mineral and Energy Resources (Financial Provisioning) Act 2018, and aimed to strengthen progressive rehabilitation planning, limit risks to the environment and improve outcomes for local and regional communities. Under the reforms, the goal for rehabilitation of voids is to achieve a safe, stable, and non-polluting landform, which can sustain a post-mining land use (PMLU). The reforms also introduced a requirement to describe rehabilitation of mined land in Progressive Rehabilitation and Closure (PRC) plans, replacing the description of such plans in Environmental Authorities (EAs). The reforms are not retrospective and recognise historic approvals for voids, meaning established voids will remain in the landscape as non-use management areas (NUMAs). The objectives of this study were to outline historic void rehabilitation planning practices, describe water quality limitations of Queensland mine voids and identify possible opportunities for improved planning

Aug 2, 2023

The occurence of high silver values in the oxidised zone of the main lode at Broken Hill is well known as a large factor in achieving the early fame of Broken Hill, and the minerals of this zone form a long list, which has been tabulated by G Smith*, and includes...

Jan 1, 1926

The Porgcra gold deposit is an epithermal gold base-metal deposit located in the Enga Province of Papua New Guinea. Gold-silver- spha le rite-galena-pyrite mineralization is related to stocks and dykes of dioritic composition which have intruded a series of folded marine sediments, mainly shales and siltstones, often with calcareous and carbon- aceous horizons, of middle Jurassic to middle Eocene age. The most intensely mineralized zone is at Waruwari Hill, where the mineralization occurs predominantly as massive mixed sulphide veins, and less frequently as quartz-chlorite veins and as disseminations. Mineralization occurs in all rock types and several phases of mineralization have been Recognized.

Jan 1, 1980

By Gibbons S. L, Ritchie I. M, Murr D. M

Fundamental studies on the transformations of iron oxides have been carried out and related to the solution conditions in the Becher process. The results show that a number of iron oxide interconversion reactions occur in the aeration reactor with the products depending on the pH, temperature and oxidation potential of the aeration liquor. It is concluded that the lack of process control in the aeration reactor of the Becher process significantly hinders the ability to predict and produce high quality single phase iron oxides of a consistent colour.

Jan 1, 1990

By Carter NB

A statistically-designed experimental program has been used to study compositional and processing variables which influence the development of strength and reducibility of iron ore pellets. The effects of chemical composition and processing variables were investigated by indurating laboratory-made green pellets, of known composition, under approximately isothermal conditions in a pot- grate simulator. Some findings from a six- variable study are summarized in the form of contour diagrams and emphasize the importance of interactions between the variables. Production of strong, highly reducible pellets is possible over a considerable range of combinations of temperature and firing time. Abrasion index (AI) and cold compression strength (CCS) improve as both these variables increase, but reducibility (R) declines, so a compromise is required. When the lime level is too low to form enough slag for bonding, the AI and CCS may be inadequate. Larger additions of lime tend to improve AI and CCS, with only slight effects on R. Finer grinding of the balling feed (i.e. higher Blaine index) tends to improve Al and CCS without

Jan 1, 1980

To enable AN-FO .tòo' be used on an equal .weight basis wish Nitro Gl reerin.e expl3oòsives r smaller diameter bore holes became necessary With consequent modifications to drill steel and burden on holes, De't'onation of AN-FO "in small diameter holes proved successful' both with 'and without primer charges but some altorat-ions were required to. adopt Anolodeòr.s to the smaller -holes, Important factors in training all operators In the new charging method were the retention of imp-,cved, fragmentat'ion, avoidance of excel ive ove:break and keeping wall rock dilution 'to an absoluato mi. iArurle ò The ò successful storage of Ammonium 14t-rate in c"!ime.tic conditions 'with daily'.-' temperature fluctuationc above and below the critical' 90¦F, has. been "achieved,

Jan 1, 1964

By Hsiung SM, Jiang YM

The orientation and location of the hydraulic legs are two very important parameters for the design of shield supports in longwall mining. Studies have shown that leg orientations and locations of a support determine the magnitude, orientation and location of the resultant support resistance which in turn affects the efficiency of the support and the ability to prevent premature roof falls in the face area. Therefore, there is a need to determine the best combination of orientation and location of the hydraulic legs for each type of shield support under various geological conditions. This paper attempts to evaluate, first, the individual role of each parameter (orientation or location) and then to determine their integrating functions in terms of ground control employing finite element analysis. Three types of shield support (2-leg and 4-leg shields and 4-leg chock shield) with various combination of the parameters are simulated and their effects are discussed. The optimum design for each parameter for each support type under various geological conditions is also discussed and recommended.

Jan 1, 1988

By Plumridge C. L, Lynch J. E, Forresty R. J

The Amanda Bel Goldfield (new name) is an area of approximately 1000 sq. km centred 65km WSW of Ingham and 150km due east of Kidston (Camel Creek homestead to Ryeburn homestead area). Gold mineralisation has been located in tightly folded sediments of the Silurian Greenvale Formation as well as in the Early Devonian Kangaroo Hills Formation and the Early Carboniferous Clarke River Formation. The area is traversed by a major NW-SE structural corridor, with many of the numerous basaltic, andesitic and rhyolitic dykes of the region sharing a similar trend. So far fourteen gold-bearing zones have been located, all of which are new discoveries delineated by bulk cyanide leach sampling and subsequent geological reconnaissance. The region has undergone three periods of deformation with gold mineralisation introduced syn-D1, post D1 - pre D , syn-D and post-D2/D , thereby revealing an involved metall~genic history. Mineralisation types include Sb, Sb-Au, Sb-Au-As, Sb-Au-As (-Pb-Zn) and Au-As. Minor occurrences of W, Pb-Zn-Ag and Pb-Zn-Ag-As-Sn are also present as are alluvial (deep lead) tin Drosoects.

Jan 1, 1989

By P Hayes, B Zhao

A range of materials are treated in zinc fuming processes to recover metal values and produce benign slag waste products. The selection of the optimum process conditions in these various technologies can be greatly assisted by the use of a chemical thermodynamic model of the system. In this paper the effects of slag chemistry on the liquidus temperatures, subliquidus phase equilibria and thermodynamic properties are described by a FACT model of the ZnO-PbO-FeO-Fe2O3-CaO-SiO2 system. In addition new experimental data on the effect of Al2O3 on the liquidus are presented. The implications of these findings for plant practice are discussed.

Jan 1, 2000

By Rao S. B, Baafi E. Y

A venturi based multi-scrubber air cleaning system has been developed for dust control along a longwall face in coal mines. The system consists of a number of scrubbers. strategically placed along the wall face which deliver cleaned air at high exhaust velocity into the middle section of the longwall cross-section thus dividing it into two zones. The aim is to maintain the walkway on the powered support side as a zone of relatively clean air. Laboratory studies have shown that the scrubber's average efficiency is 90 per cent. Field trials in three longwall faces have shown that. under normal operating conditions. 40 to 50 per cent average protection efficiency can be achieved within 3 m to 4 m downstream of the scrubber. A three-dimensional finite element computational fluid dynamic model. FIDAP. was used to simulate the airflow patterns the dust concentration and the scrubber dust control technique at a typical longwall face. Results of simulations tally very well with the field results.

Jan 1, 1995

By Sharpin PC

The countercurrent gas-solid-heat transfer during the drying of brown coal briquettes in the pilot carbonization plant at Morwell has been analysed and theoretical gas and solid temp-erature distributions through the drier have been calculated. Although the calculations rest on several simplifying assump-tions, to be corrected as the experimental work develops, the theoretical temperature distributions compare well with those observed in practical operation. Valuable conclusions are reached as to the effects of changes in drier operating con-ditions on the rate of drying of the briquettes which-controls the 2 strength of the char produced. The analysis shows why a limitation was reached in the improvement of char-strength in the pilot plant in 1961 and a prediction is made of ' a way ' in ' which the limitation could be overcome.

Jan 1, 1963

By Grant JR, McKavanagh BM, Dear SJ

A geophysical technique of rock mass assessment for engineering purposes is being investigated and shows positive correlation with direct structural logging and mapping techniques for the detection of major geological features. The technique is cross-hole acoustic surveying incorporating high speed signal averaging, with a maximum hole separation in excess of 30 metres in hard unfractured rock masses. The bulk of the field test work was carried out in open stopes in the copper ore bodies of Mount Isa Mines Limited. The investigation forms part of an integrated study of blasting in mining, aiming for fragmentation control through blast design modification. The rock quality factor, Q, is presented as a blasting index and can be determined for a significant portion of a production stope.

Jan 1, 1981

By S Prakash, P S. R Reddy, S K. Biswal, V N

The beneficiation potentials of two Indian iron ore slime samples by flotation technique using both cationic and anionic collectors are investigated. The direct and reverse flotation of slimes using oleic acid and dodecylamine as the collector have been studied using both conventional cell and flotation column to upgrade the iron content. The characterisation studies of iron ore slimes indicated that the samples are extremely fine in nature and contain substantial amounts of martite, magnetite, goethite, limonite, kaolinite and quartz beside hematite as the dominant iron mineral phase. The samples on average contain around 52 - 58 per cent Fe, four to seven per cent SiO2 and five to six per cent Al2O3. Taking into account the physico-chemical properties of the slimes, it is attributed that both the samples need to be deslimed by hydrocyclone before flotation. The results of both cell and column studies on sample I showed that a feed containing 57.5 per cent Fe could be upgraded to 65.5 per cent Fe at 50 per cent overall recovery with simultaneous decrease in SiO2 and Al2O3 content to 2.3 per cent and 1.8 per cent respectively by using oleic acid as the collector. In the case of sample II, it has been established that reverse flotation of silica is the better technique to improve both the grade and recovery of iron. Batch flotation studies in cell indicated that a product with 63.1 per cent Fe could be obtained at 40.0 per cent yield with 63.6 per cent iron recovery by the combination of reagents such as gum acacia, sodium hexa meta phosphate and dodecylamine. The performance of column flotation techniques is far superior to that of the cell with respect to both grade and recovery. The concentrates are found to be quite suitable for commercial exploitation as pellet feed.

Jan 1, 2005

By Misra V. N, Spottiswood D. J

In recent years the column flotation process has gained worldwide acceptance for processing various types of minerals under different circuit configurations. In an age when real prices of many mineral commodities are in decline and mining and labour costs are rising in real terms, it is more important than ever that concentration processes be not only efficient but also cost-effective. The column flotation process can give better metallurgical performance as well as involve lower capital and operating costs compared to conventional mechanical cells.This paper reviews the literature on columns and the effects of various column parameters on performance of the column flotation process. The history and principles of operation of the column flotation process are briefly discussed by way of introduction.

Jan 1, 1995

By Grano S. R, Lauder D. W

Investigations on the oxidation behaviour of chalcocite and its rejuvenation by hydrogen sulphide ion have been undertaken. Chalcocite oxidation was measured using X-ray photoelectron spectroscopy (XPS), zeta-potential and by dissolution in et

Jan 1, 1997

An exploration and preliminary mine design contract was undertaken in Thailand to establish whether adequate lignite resources existed for the addition of future power generation plant through to the year 2000. The lignite ranges in heat value from 14 to 24 MJ/Kg (air dry basis) and occurs in 2 major seams consistituting measured reserves of 536 Mt (with an ash cut-off level of 45 % on an air dry basis) and a strip ratio of 4.1 bank cm/t. The paper describes the pre-planning, programming, equipment used, project management, logistics and exploration methods adopted to undertake the contract in a monsoonal area using Australian drilling and geophysical contractors.

Jan 1, 1983