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By A C. Edwards

The Mongol-Okhotsk belt consists of detached fragments of the Circum Pacific fold belt which have been trapped within the Mongol-Okhotsk fold belt. In its western part, the structures of the belt form an east-facing loop that is not connected with the other orogenic structures of Central Asia. In the eastern part of the belt (the Mongol-Okhotsk suture zone) the terranes form a zone between the Siberian craton to the north and the Bureya composite terrane to the south, that is linked with the Circum Pacific belt. The accretionary terranes, together with their Precambrian backstops, form a series of consistently-stacked, paired units that are bounded by northwest and north trending sinistral strike-slip faults. The ages of the rocks forming these accretionary complexes vary from Late Precambrian - Carboniferous in the west to Cambrian - Jurassic in the east. The terranes developed due to a progressive westward stacking of the accretionary complexes during the process of accretionary growth. The magmatic rocks young eastward indicating that migration of the magmatic front of the arc followed the eastward growth of the accretionary complexes. The accretionary terranes may be differentiated by their Paleozoic lithological assemblages. Only the Selemdzha, Niman, and Kerbi terranes located in the eastern part of the Mongol-Okhotsk suture zone contain significant amounts of black shale, and it is these terranes that host the bulk of the hardrock and placer gold mineralisation that is present within the suture zone. Gold mineralisation is present both as vein style and disseminated mineralisation within structural duplexes.

Jan 1, 1999

The subject which I have chosen for my paper is one that I am sure has occurred to the minds of nearly every mining man on these goldfields at some time or other. I refer to the carrying out of hydraulic mining on a fairly large scale on some ofthe alluvial areas of the West Australian goldfields. There are many, no doubt, who have the question ready at the present moment, "But where is the water coming from? " However, the great difficulties in the way are not due to the want of natural facilities, but due to the fact that sufficiently large areas cannot be leased for this purpose under the present Mining Act. Now, ever since the inception of the West Australian goldfields there has been the old familiar cry when referring to some alluvial gully or flat, "I wish I had a head of water to sluice that ground," but what seems an impossibility at times can be brought to a very great possibility by the use of a little thought and the expenditure of the necessary capital. This is so as regards West Australia with sluicing which, in spite of the its having so many detractors, can be carried out successfully in certain localities if the ordinary facilities on the part of the Govenment are given, and on the other hand the necessary capital is supplied. Alluvial gold areas, I propose now to draw your attention to first of all, the numerous alluvial areas that exist around Coolgardie, Kalgoorlie, Bulong, Kurnalpi and many other centres. Some of these areas have afforded fortunes inthe early days to the alluvial miner, and also afforded a living for years to many diggers' by the use of the dryblowing...

Jan 1, 1901

By J Graaf, R A. Murrell

Gold Fields Australia is constructing two major ventilation shafts at the Wallaby gold mine in Western Australia. The new ventilation shafts are required to facilitate the long term ventilation strategy for the mine, thereby allowing continued extraction of ore beyond 1000 m below the surface. The construction work has involved all of the challenges that shaft construction can throw up, including challenging geotechnical conditions, unexpected high water inflows and major circulation loss during pilot hole drilling for raise boring. An extensive geotechnical and hydrological investigation program was undertaken prior to awarding the shaft construction contracts. While most of the risks were identified, several proved to be much more challenging than expected. The shaft construction methods included conventional sinking into the fresh rock profile in each shaft, followed by raise bore pilot hole drilling and reaming. A headframe was constructed for the first shaft, which was sunk to 92 m with a stage suspended in the shaft to facilitate the concrete lining and provide rope guides for the kibble winding. Drawing from experience when sinking the first shaft, additional ground pre-conditioning was implemented for the second shaft, which was pre-supported with continuous piles to 28 m followed by sinking to 50 m using a crane instead of winders and a headframe. Following the conventional sinking through the weathered zone in each shaft, the shafts were completed using a raise bore. The first shaft utilised a riser pipe and rotary vertical drilling system (RVDS) with the second shaft having utilised a dual rotary rig for pilot hole drilling. This paper reviews the site investigations undertaken, construction methodologies applied, the results achieved and the lessons learnt.CITATION:Murrell, R A and Graaf, J, 2017. Shaft construction at the Gold Fields Wallaby mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 321–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By J Wesseloo and Y Kim, Y Potvin, G Mungur, D Grant

At the previous MassMin conference held in Sudbury in 2012, the authors proposed a new framework going beyond dilution and equivalent linear overbreak sloughing (ELOS) for stope reconciliation in relation to the planned stope design. More specifically, the new process investigates performance outcomes including rock overbreak (OB) and fill overbreak (FOB), rock underbreak (UB) as well as geomechanical and operational aspects such as blasting, fragmentation and other production data.Based on the findings of the original 2012 study, a comprehensive data gathering program has been undertaken involving design and reconciliation data from 43 stopes mined between September 2012 and October 2014 at BHP Billiton’s Olympic Dam (OD) operation. The new database structure was based on four types of data:stope definition and performance datastope geometrygeotechnical parametersoperational parameters.The new database allows a more in-depth investigation of stope performance. It is now possible to quantify and analyse UB and OB performance from each wall individually as well as the crown. In this paper, the influence of several parameters on recent stope performance at OD is analysed. The underlying reasons for stope wall performance outcomes are discussed in this paper.CITATION:Potvin, Y, Grant, D, Mungur, G, Wesseloo, J and Kim, Y, 2016. Practical stope reconciliation in large-scale operations part 2, Olympic Dam, South Australia, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 501–510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

The Physical Basis of Non-Random Breakage in an Iron-Oxide Ore Hosted Copper Gold Ore

Sep 13, 2010

By T King

This paper reviews the changes in the coal industry over the past 30 years and attempts to predict the trends over the next ten years. The last 30 years have seen a steady concentration of production into fewer, larger mines, which operate on 3: more continuous basis, and a major increase in productivity per employee. Coal exports have increased from zero to almost half the country's total production. As well as major changes in exploration and mining equipment and the increasing use of computer tools, the industry now operates in a relatively new regulatory and commercial environment.   Safety legislation now requires the writing and enforcement of policies and procedures by the mining companies, rather than adherence to inflexible regulations enforced by an Inspector. Accident rates have decreased dramatically. The transition from coal mining licences to permits, requiring landowner consent and resource consents, is well under way. Environmental controls are now an essential aspect of the industry.   Equipment suppliers now offer maintenance services, production guarantees and flexible financing.  Contract miners offer mine design and restoration as part of the contract. In a similar approach, Solid Energy now offer an ash disposal service and assistance with resource consents to their customers as well as investment in technology to ensure a consistent product to demanding specifications. Solid Energy has proposals for energy centres which install and operate the coal burning appliances and simply sell energy to the customers. The next 10 years should see an intensification of these trends of bigger mines, more exports and greater technology and a 'package' approach to customer service.

Jan 1, 1997

Geochemical data on Australian granites and pegmatites, and the mineral components of these rocks, are compared with that obtained in similar studies in the U.S.S.R. and elsewhere.The geochemical character of tin granites and the trace chemistry of their component minerals, particularly biotites, have some significance as ore guides in prospecting for tin.The primary geochemical dispersion of tin can be readily tested both in the laboratory and field by colourimetric methods, after volatilization with ammonium iodide, using modifications of the method described by Wood (1958).Secondary dispersions of tin in residual soils or alluvia can likewise be readly tested by rapid colourimetric methods in the field, but simple hydraulic methods, handling larger sample volumes, give reliable outlines of dispersion patterns.INTRODUCTIONThe search for tin ores, whether lode or placer in type, is usually directed on genetic grounds to country within or adjoining acid intrusives.A long established means of prospecting is to test samples for cassiterite by panning or other hydraulic separation.These methods can be used on crushed lode material or the natural materials from placers.With the advent of new techniques for extraction and for colourimetric analysis for tin (Wood, 1958 and Ross and White, 1961) a means is available for rapid analysis of materials not susceptible to quantitative testing by hydraulic methods because of the fine sizings of cassiterite or the occurrence of tin structurally held in minerals. The new methods thus opened up the field of tin prospecting by extending the search for ore guides to genetically associated rocks and minerals, wall ror-ks of veins and a wider range of superficial deposits.

Jan 1, 1963

Pressing-Drill Method - A Representative Method for Taking Analysis Samples from Recycled Materials

Sep 13, 2010

The Archaeozoic Willyama Complex at Broken Hill has suffered several periods of deformation and metamorphism. New structural and petrological information together with that available from the literature gives a picture of the metamorphic evolution of the Barrier Ranges. Several epochs of metamorphism are recognized, and potassium-argon dating of minerals has been applied with limited success to the resolution of these epochs.INTRODUCTIONAdvancements in the mineral industry at Broken Hill over the past eighty years have been accompanied by a continual striving towards increased understanding of both the geological history of the Barrier Ranges and the environment of the Broken Hill ore deposits. However, although many detailed studies of selected localities and particular-aspects of Broken Hill geology have been carried out recently, the regional geology of the Barrier Ranges as a whole has received little attention from a petrological viewpoint since the pioneer investigations of Mawson (1912) and Browne (1922). There still remains a great need for regional surveys combining field studies of the habits, structures and outcrop relationships of the various rock types with laboratory investigations of their chemistry, mineralogy and microscopic ,fabrics. Recording observations arising from three brief visits to the Broken Hill area during 1959 and 1963 may stimulate further surveys.During one of these visits, the generosity of the Zinc Corporation Limited in providing field transport and geological guidance enabled the writer to collect material and study field relationships and appearance of the various rock types at numerous localities covering most of the Willyama outcrop. A complete study has not been conducted...

Jan 1, 1963

Various steps, and complete sequences, for the recovery of lead and zinc from a mixed sulphide concentrate, high in silica and pyrite, have been tested.Oxidation steps of roasting in air or in a sulphating atmosphere and use of aqueous acidic, ammoniacal, and near neutral oxidation media were compared. Oxidation roasting or use of acidic media appeared most useful. Procedures for dissolution of zinc from calcines using sulphuric and sulphurous acid to avoid silica gelation problems are compared and a direct leaching procedure with sulphuric 'acid at controlled pH shown to be the most useful.Methods for the removal of germanium, nickel, and magnesium from zinc sulphate solutions prior to zinc electrodeposition were tested. The recoveries of zinc from ammoniacal solutions by electrolysis and distillation are compared.The dissolution of lead compounds from the residue of zinc extraction by amine and ammoniacal ammonium sulphate (AAS) solutions Was tested. Lead, sulphide was precipitated in filtera'ble form from AAS solutions. The reduction of lead sulphate to lead sulphide with sulphur was difficult, but possible. The various steps were used to deveiop five complete processing sequences, of which two were shown to be technically feasible and have potential economic viability.

Jan 1, 1975

In this address I look back over the past 40 years of mineral exploration in New Zealand û essentially the period since the Second World War (ie since 1945). It was the period of my personal involvement, and indeed of the personal involvement of a number of you. Luckily it was aperiod of great interest and activity. In the previous 50 years, virtually nothing had happened, and it is kindest to draw a veil over that period. In the very important earlier 40 years (1855 - 1895) the New Zealand gold rush occurred. That must have been a fascinating, rewarding period, which has been thoroughly documented by better historians than myself. I will simply comment firstly that its mineral explorers (gold-prospectors) were very successful indeed, and found most localities of the minerals they sought, in spite of using very different methods from ours of today. Secondly, they were preceeded by one of Maori exploration, which searched for a much restricted list of minerals, but succeeded in finding virtually every locality we know of today. The explorers of both of these early periods were obviously highly successful, but, in the time available, I must restrict myself to the period since 1945. I am currently editing the effective up-dating of Gordon WilliamsÆ 'Economic Geology of New Zealand' (1974). It covers the last 12 years or so. Many of you are contributing to that volume û both as authors and as referees û and I would like to take this opportunity of thanking you all. Although this new volume excludes the energy field, many of us have been involved in it, and I am therefore including energy minerals in this review, as Williams did in 1974.

Jan 1, 1987

By W. J. LANGRON

This paper describes the results of VLF-EM test surveys, using the Ronka EM-16 equipment, over a selection of environments in Australia and Papua.Using comparisons with known geology, drilling information and other geophysical work it is shown that the maximum depth of penetration of the method is about 100 ft but is considerably less than this in most areas.The author believes the method could aid in geological mapping and provide a useful adjunct to aeromagnetic surveying in some areas.

Jan 1, 1972

The reactions between molten aluminium and cryoIite have been determined from a material balance of all components involved in the process. The interpretation of results were supported by x-ray diffraction studies of the evolved vapours, quenched electrolyte samples, and side-reaction products.The most important reaction involves the formation of both Na2F (sodium subfluoride) and chiolite in the fused electrolyte. The Na2F accelerates vaporization of the melt. Some AIF (aluminium monofluoride) may also be formed but the proportion of this is much less than for the former subvalent compound.

Jan 1, 1968

According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

Polyacrylamide flocculating agent has been used in the Leaching Division 'of the Risdon Works of the Electrolytic Zinc Company of Australasia Limited since October, 1960. The number of thickeners in the continuous thickening stage was thereby reduced from eight to three. There has been an increase of 25 per cent in throughput and a reduction of solids in thickener over-flow from 3-4 g/l. solids to 0·5 g Ir. solids. Reagent addition has been at the rate of 0·25 lb Separan NP10 per ton solids.Additionally there has been a gain of 3 per cent in current efficiency as the direct result of the addition of Separan NP10 to purified cadmium sulphate solution priOl; to electrolysis for cadmium metal. A smoother deposit has resulted and it has been possible to increase deposition time between strippings from 47 to 71 hr. However, there has been a slight increase in the lead content of the cadmium metal produced.The use of Separan NP10 to settle copper bearing residue in a batch process stage has resulted in a five-fold increase in settlement rate and a reduction in purification cycle time.INTRODUCTIONThe Electrolytic Zinc Company of Australasia Limited, Risdon, Tasmania, produces zinc by electrolysis of purified zinc sulphate solution, the raw material being zinc sulphide concentrate. In the Risdon process (Van Arsdale, 1953; J ohnstone, 1953; Ross, 1949) the compound zinc ferrite (ZnO.Fe203) is formed during the concentrate roasting stage. When the roasted material is leached in dilute sulphuric acid the zinc ferrite is not attacked, and it remains as part of the insoluble leach residue, of which it may form as much as two-thirds of the whole. The remainder is mainly unroasted zinc sulphide, unleached zinc oxide, lead sulphate, gypsum, silver compounds etc. The zinc in the residue may be 10 per cent of that in the original concentrate.Continuous thickeners are used to recover the valuable residue from the impure zinc sulphate solution and the...

Jan 1, 1963

Building the Unified Comminution Model The Unified Comminution Model (UCM) was formulated with the vision of bringing all comminution models onto a common base. The structure of the model relies on knowledge of the mechanical environment in the comminution devices to predict the modes and rates of collision in a device. A detailed understanding of the breakage modes and an ability to correctly test these modes for the ores in question is then required to feed into the UCM. A model structure has been developed that has the capability of dealing with multiple modes of breakage, such as low energy impact surface damage, chipping, sliding abrasion, cumulative impact body breakage and the transition of rock between modes. A critical review is presented on the shortcomings and limitations of utilising the discrete element method (DEM) to provide the mechanical environments. The assumptions and applicability of utilising DEM in milling models are presented and proposed routes to building a realistic mechanistic model are proposed. Based on this more realistic measures of collision energy have been derived from the DEM simulations, which better mimic the real breakage tests. Generic forms of the collision energy distributions have been observed and developed into functional forms for use in the simulation environment. The method of application of this model to a pilot SAG mill is presented.

Sep 13, 2010

By Madgwick J. C

Microaerobic biodegradation oflow-grade manganese dioxide slurry tailings was demonstrated in enrichment cultures treated with dilute molasses at 30°C and pH 5·8. Supplementary nitrogenous nutrients, yeast extract addition and pH adjustment were not required.Continuously stirred, air-limited reactors were superior to still intermittently agitated cultures, in that, at 5 per cent (w/v) MnOz tailings and 5 per cent (w/v) molasses, the yield of 0.12 g Mn++/g molasses, the rate ofleaching of 1·06 g Mn++/l/d and a recovery of Mn++ of 58 percent from MnOz were 2·8 times, 1·7 times and 1·9 times greater, respectively. The best compromise in yield (0·45 g Mn++/g molasses) and rate ofdissolution (0·73 gMn++/l/d) was at 1 per cent (w/v) molasses in a stirred reactor.Where leaching organisms were separated from sterile ore by a bacteria impermeable membrane leaching was shown to be some 20 per cent due to diffusible metabolites and 80 per cent due to a direct contact between the bacteria and the ore particle's surfaces.

Jan 1, 1986

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

By T M. Campos, H A. Petit, L M. Tavares, R Olympio

Much practical experience has been gathered in the last 30 years of application of high-pressure grinding rolls (HPGR) integrated with ball milling in size reduction of fine iron ore concentrates. The company Vale S.A, in Complexo de Tubarão (Brazil), was one of the pioneers applying the technology prior to pelletisation with an outstanding size reduction energy efficiency in the circuit and a significant increment in the specific surface area of the product. Recent studies by the authors demonstrated benefits of modelling and simulation to improve the performance of HPGRs in this particular application, with the model being able to describe HPGR performance under different operating conditions and under variations of feed size distribution. Despite these important advances, this modelling approach has only been used offline and under steady-state conditions. The present work applies the modified Torres and Casali model proposed by the authors in pseudodynamic simulations. The ability of the model to predict the characteristics of the product in real-time is evaluated using data available online for the pellet feed preparation circuit. Results demonstrated the model capabilities to map the physical operation and give a realistic representation of the process. Additionally, the model is demonstrated to be able to support the pellet feed production by providing extended real-time information of the process, making it a useful tool for improvement of the operational strategies and process stability.

Aug 24, 2022

The El Pe±on gold-silver deposit comprises four epithermal, low-sulfidation veins, which contain 2.9 million oz Au and 48 million oz Ag. Provisional data on alteration mineralogy, fluid inclusions, and vein textures constrain the chemistry and hydrology of the hydrothermal system responsible for ore mineralisation at El Pe±on. Alteration minerals include quartz, adularia, albite, illite, smectite, calcite, chlorite, and pyrite. Alteration minerals suggest the existence of near neutral pH, low salinity hydrothermal fluids, which circulated over an area greater than 18 km2. Complex mineral zonation patterns result from variations in host rock permeability and composition, overprinting alteration possibly produced by thermal waters from surficial and peripheral parts of the hydrothermal system, and supergene weathering in the hyperarid environment. Upflow zones were focused along N-S and NE trending structures, producing crustiform quartz-adularia+carbonate veins. Fluid inclusion data indicate vein deposition from low salinity (

Jan 1, 2002