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By P R. L Browne

Study of geothermal systems in the Taupo Volcanic Zone (TVZ) has significantly advanced our understanding of the processes of epithermal mineralisation. The three main lessons learnt are: 1. knowledge of their chemical anatomy; 2. precious metal transport and deposition; and 3. hydrothermal alteration zoning. These are described in the context of ore formation and exploration.

Jan 1, 1997

The Granites Gold Mine has far exceeded the design capacity of 300,000 tonne per annum during its first sixteen months of operation. The presence of considerable free coarse gold has made it imperative that the gravity section operate at maximum efficiency. The inadequacy of acid digest- ing facilities and trying climatic conditions prompted management to initi- ate investigations into the use of Intensive Cyanidation as an alternative method for upgrading gravity concentrates prior to smelting.

Jan 1, 1988

This paper reviews an analytical model that defines the relationship of weight-weighted or volume-weighted average haulage distance with bench height and other related parameters; presents the optimum bench heights under various conditions in terms of minimising the weighted average haulage distance of ore/waste during the full lifetime of an open pit mine, and discusses the truck-haulage economics of mining open pits by high bench, specifically by 15 m, 18 m and 20 m bench through marginal analysis. The observations from these analyses disprove the previous conflicting assertions that the overall weighted average haulage distance either increases or decreases monotonically with bench height. It is concluded that: (i) an increase of bench height to 15 m from 12 m is likely to be viable under the general conditions of large-scale deep open-pit mines; (ii) the reduction of haulage cost is limited with the case of increasing bench height to 18 m from 15 m; and (iii) the feasibility of mining open pits by 20 m benches is generally questionable. These conclusions may serve as a useful guide for those who advocate open pit mining by high benches.

Jan 1, 1995

The increasing use of Ditch Witch trenching to define gold ore bound- aries in supergeme enriched near surface open cut mines has led to the consideration of using this technique for other sampling procedures. The use of Ditch Witch trenching for exploration has not been widely used and it is anticipated that the technique described will help stimulate more extensive use and new sampling techniques.

Jan 1, 1988

By Penttila V

The Paleoproterozoic Hitura Ni-Cu deposit in western Finland is in an ultramafic igneous complex composed of two subvertical plug-shaped bodies embedded in intensely migmatised felsic gneisses. The ultramafic complex is not far from a north-south trending graphitic and sulphidic gneiss zone interpreted to be a primary sulphide-graphite unit in the metasedimentary sequence. The sulphide accumulation exists as a zone parallel to the contact of the northern ultramafic body. The ultramafic rock types, now mainly serpentinites, have primarily been olivine adcumulates in the core grading to olivine orthocumulates and pyroxenites towards the margins. Coarse-grained felsic pegmatite veins injected serpentinite where they now exhibit prominent zoned alteration rims of chlorite, antophyllite and talc. The serpentinite core of the body was primarily an olivine adcumulate derived from a tholeiitic or high-Mg basalt parental magma with about 11 wt % MgO. Metamorphism and alteration have totally changed the igneous mineral compositions and the rock types are serpentinites (from olivine adcumulates), ambhibole-bearing serpentinites and amphibole-chlorite rocks (from pyroxenites). As the result of CO2 alteration talc is an accessory mineral throughout the serpentinite. Like silicates, also sulphide minerals are altered. In the core of the body the low-grade sulphide dissemination still reveals primary igneous interstitial forms. The core sulphides are now mackinawite, pentlandite and valleriite instead of primary igneous pyrrhotite and pentlandite derived from Mss. At the marginal zone the heavy dissemination and net-textured sulphides display pyrrhotite-pentlandite-magnetite intergrowths with magnetite films along cleavage of sulphides, mackinawite in pentlandite and exsolution textures of different low-temperature pyrrhotite phases as the result of alteration processes. Mechanically weak rocks, complicated structures and textures of the ore, magnetite and mackinawite intergrowths in pentlandite and readily-floating MgO silicates cause problems in exploitation of the deposit. Solution to problems come from selective stoping, three-step classification in grinding, froth-washing technique and on-line process control based on ore type determination from process data using an expert System

Jan 1, 1996

By T Cutts

Since 1989 Kalgoorlie Consolidated Gold Mines has managed the Kalgoorlie gold operations of joint venture partners Normandy Mining Ltd and Homestake Gold of Australia Ltd. Current production from the Fimiston Open Pit is approximately 650 000 ounces per annum. The mine incorporates a multitude of narrow shear hosted, subvertical lodes, predominantly within Golden Mile Dolerite. Traditionally KCGM has used blasthole based grade control in the Fimiston pits. A single sample is taken from vertical production blastholes, drilled on ten metre benches. This process was improved with the addition of infill drilling along blasthole rows to provide additional samples across strike. However the limitations of adequately defining subvertical mineralised structures with vertical blastholes remain. In 1997 the first of two trial areas were drilled with close spaced, inclined Reverse Circulation (RC) drilling. These tests indicated that RC based grade control had the potential to provide significant advantages. These include:improved delineation of mineralised structures, particularly across strike; reliable short-term mine schedules based on the advance data available from drilling over three benches; and the angled RC drilling is capable of providing samples of near stope and stope fill material which often remains unsampled by blasthole drills due to the safety constraints around unstable underground openings. Based on the success of this initial work RC based grade control was gradually implemented across production areas commencing September 1998. Some of the many challenges faced include:development of effective procedures and systems for the planning, logging, interpretation and modelling of the RC data; obtaining adequate drill coverage due to mine scheduling constraints and restricted access around underground openings; requirement for integrated systems to handle either blast hole or RC data; and development of effective methods to evaluate the performance of RC grade control. RC based grade control is delivering significantly improved lode definition, grade estimation and subsequent ore classification.

Jan 1, 2000

Wastewaters from Mining Projects both gold mining and coal mining generally have minerals in solution or very fine material which does not settle out quickly. These waters in the past have been discharged into the nearest water course and caused extensive pollution.

Jan 1, 1986

Cook Colliery currently mines in the Argo Seam, beneath old workings in an overlying seam. The Argo seam is up to 4.8 m thick and a continuous haulage system behind an ABM25 is used to develop first workings. Current partial secondary extraction utilises floor stripping and pocketing or sumping first working pillars on retreat. The following paper summarises this recent secondary extraction experience, particularly from a geotechnical perspective, but also considering production and ventilation issues. Outcomes and learnings are presented for mining in this challenging and close multi-seam environment. The sealed castor seam workings are within 20 m, and vary from unmined areas to large first working pillars, to partial extraction panels and full extraction panels. High stress remnant pillars and goaf-edges are notable mining considerations. The mining environment is further complicated by faulting, thrust zones and weak laminated roof.

Nov 25, 2010

I trust you know now or will know by the time you havecompleted your degree and added a little on-the-job experience,how to make the product from the mine you are working for. Butyou may not know the process to turn it into dollars, which ofcourse will be the life blood of your company. I am not going topromise to turn you into super salesmen, but I hope I can takeyou beyond the level of believing that selling our mineralproducts is as simple as putting in it on to a train, waving itgoodbye and waiting for the cheque to turn up in the mailbox afew weeks later.

Jan 1, 1994

By Kubo H, Kubita K, Morinara M

A quantitative method for predicting the mechanical properties of zinc alloys is proposed on the basis of the molecular orbital calculation of electronic structures. A new parameter which is the s-orbital energy level, Mk , of alloying elements in zinc was introduced into this method. This Mk parameter correlates with the electronegativity and the atomic radius of elements. The compositional average of this parameter varied linearly with the tensile strength and the hardness of commercial alloys and some alloys developed by Mitsui. This electronic method was very convenient in designing high performance zinc alloys efficiently.

Jan 1, 1993

The importance of the minerals industry to Australia is briefly reviewed and the professional specialists essential for the industry identified. The average first degree graduation numbers in geoscience, mining engineering, metallurgy/materials and chemical engineering are shown and compared with the postgraduate numbers. Demographic trends in population are reviewed and the implications for the required numbers of trained specialists indicated. Short/medium and long-term possible solutions to potential shortages of trained personnel are canvassed.

Jan 1, 1997

By Thompson P, Sharma Y

The paper describes the methodology and results from a study carried out by Telfer Gold Mine to optimise the materials and costs involved in construction of the pad for their dump leach operations. The investigation involved large-scale field testing of five different types of liner and a number of different cushion and drainage layer configurations. The aim was to identify the most cost effective construction methods to allow the final dump height to be increased from 45 in to 60 in without causing significant damage to the liner. The effects of dump height on permeability were also investigated. These methods are described and results presented. The findings indicated that modifications to the existing liner/cushion layer/drainage layer configuration used previously at Telfer would actually reduce overall construction costs rather than increase them despite an increase in overall dump height. Relative construction costs are presented.

Jan 1, 1994

By Hinchliffe WD, Griffin A

The desorption of gold from activated carbon is promoted by adding organic solvents to aqueous cyanide solutions. At 65-80¦ the elution of gold is fast and is not affected by water quality. The Micron Procedure involves pretreatment of the loaded carbon with NaCN/NaOH followed by elution with methanol vapour and condensate. Carbon is packed into a column above the distillation pot and acts as a fractionating column. Recovery of the methanol condensate leaves a methanol free concentrated gold solution and carbon containing

Jan 1, 1984

By Donald D

A number of standard tests are conventionally carried out to characterise strength properties of rock. The values of the parameters obtained are often affected by planes of weakness or defects in rock structure. For the purpose of mine design, the range in values or the class of the strength (obtained from a number of tests) is generally more important than a precise value (obtained from a single or limited number of tests). Research has been conducted to establish a relationship between an indentation index and the strength of the intact rock material from the Eastern Goldfields of Western Australia. The Tamrock Raise Boring Index (RB-i) test, which is quick and easy to perform, was selected as the indentation test. The results show that, for heterogeneous, strong to very strong rock, there is a good correlation between the indentation index and the uniaxial compressive strength and tensile strength.

Jan 1, 1996

The epizonal Ag-Pb-Zn vein deposit at San Bartolome is characterised by a base-metal sulphide assemblage containing the spectacular development of interpenetrating, bladed networks of pyrrhotite which have been replaced by marcasite and pyrite. A similar assemblage displaying the same crystal habits and textures are also a diagnostic feature of the Sn and SnAg deposits ofBolivia. On this basis, it is reasonable to conclude that both deposits were formed from fluids of similar nature and origin. Although no economic accumulation of Sn is known in San Bartolome, further comparison of the geologic setting, age, mineralogy, fluid inclusion data and magmatic association of this deposit with the Bolivian systems has highlighted additional similarities consistent with a hypothesis that more extensive Sn mineralisation might exist in the San Bartolome area.

Jan 1, 1995

By Savidis G

The characteristics of 'Z' (Back-over run) and 'R' (Reverse) ventilation systems are dis- cussed in relation to their suitability for longwall mining. Experience in European mines has been described as a basis for comparison with Australian conditions. In assessing the merits of each ventilat- ion system, such factors as longwall layout (pillar design, number of headings and gateroad stability), the need for gas drainage and bleed- er systems, as well as the influence of seam dip have been considered relevant. The R system is generally applicable for single and two heading development in seams where gas emission is a less serious problem. In contrast, the lower extraction to development ratio of the Z system (which arises from using three or more heading layouts) is considered more favourable where high gas emission occurs. The Z system provides greater flexibility with respect to the provision of refreshing air at the tailgate end, access of men and materials, installation and retrieval of gas drainage systems and the ability to interchange main- gate and tailgate roadways in cases where roof strata loads are difficult to control, or where cpam in hac an influrnra

Jan 1, 1983

By O Aydan, K Sugiura, A Sakamoto

It is well known that some sinkholes or subsidence take place from time to time in the areas where abandoned room and pillar type mines exist. The authors have been involved with the stability of abandoned mines beneath urbanized residential areas in Tokai region and there is a great concern about the stability of these abandoned mines during large earthquakes as well as in long term. The 2003 Miyagi Hokubu and 2011 Great East Japan earthquakes caused great damage to abandoned mines and resulted in many collapses. Particularly the effect of the quality of backfilling of abandoned mine below the urbanized areas is very important under static and dynamic conditions. The authors present the effect of the quality of backfilling on the ground subsidence associated with abandoned lignite mines under static and dynamic conditions and discuss its implications on the urbanized areas above abandoned lignite mines in this study. CITATION:Aydan, O, Sugiura, K and Sakamoto, A, 2018. The quality of backfilling of abandoned lignite mines on ground settlement under static and dynamic conditions, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 134–141 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Hikosaka A, Chiba A

In a fundamental study of the physical chemistry of steelmaking slag, equilibra bet- ween hydrogen-water vapour gas mixtures and liquid slags contained in solid iron crucibles have been measured for four binary slags, FetO-CaO, FetO-Si02, FetO-TiO2 and FetO-Al203 at 14000C. From the data, the activity of iron oxide and the ratio of ferrous and ferric ions (A = Fe3+/Fe2+) were calculated for the slag composition. The best ionic model is found to be that based on regular solution of cations. The oxygen distribution between slag and metal is quantitatively expressed by this model over a wide range of slag composition.

Jan 1, 1980

Implementation of an Energy Efficient Dry Grinding Technology into an Anglo-American Zinc Beneficiation Process

Sep 13, 2010

By Clifford C. E

1 eat my peas with honey I've done it all my lifeIt makes them taste rather funny But it keeps them on the knife.Innovation is that elusive characteristic which involves the determination of multiple and unique response to a problem, and then commitment to and action from the best of the alternatives.

Jan 1, 1993