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By Edmonds W, Giles C. W, Webb R. J, Gum J. C

Gold production from The Granites - Tanami Goldfield during 1993 is expected to exceed 8 t, eclipsing that of the traditional Northern Territory gold mining districts of Tennant Creek and Pine Creek. This is the result of dedicated and successful exploration, and the consequent discovery of new orebodies such as those at Dead Bullock Soak.Following granting of access to regional exploration areas in 1988 and identification of favourable host rocks in the Schist Hills area, North Flinders Mines (NFM) began a methodical exploration program of detailed geological mapping, rock chip sampling, costeaning and various types of drilling. The first resource of 600 000 t of 3.3 g/t gold was announced in mid-1989. This has grown progressively with systematic exploration to the currently published resource inventory of 6.6 mT @ 5.4 g/t, (as at 31.12.92) contained in six separate orebodies within the Dead Bullock Soak Mineral Lease at Schist Hills.

Jan 1, 1993

By G MORRIS

The mining industry has been rightly proud of its environmental achievements and it would be fair to say that in some areas the Australian mining industry is at the forefront of world practice in environmental management and mine rehabilitation. The `environment' has certainly been a growth area over the past three decades with growing awareness in the 1960s, some large battles and the of significant legislation in the 1970s. The most important period however has been the 1980s and so far the 1990s where, in addition to the of some more rigorous legislation, we have seen the practical application of environmental management/rehabilitation Techniques.

Jan 1, 1992

By Dixon D. R, Sparrow G. J

Pressure leach liquors from the pressure oxidation of a bulk flotation concentrate prepared from a complex Cu-Pb-Zn sulphide ore were treated to remove iron, either by pressure oxidation (the Hematite process) or with particles of magnetite (the Magnetite process), followed by cementation of various metals with zinc dust to obtain a purified solution from which zinc was electrowon. Satisfactory iron removal was achieved by both processes after neutralisation to pH 4.5 or 5.5. Pressure oxidation of the liquor at 200¦C and 690 kPa oxygen overpressure, conditions similar to those of the Hematite process used in the zinc industry, resulted in the precipitation of the iron as hematite. With the Magnetite process, an iron hydroxide was precipitated onto magnetite at atmospheric pressure and ambient temperature and removed by a magnetic separation step. The performances of both these processes for the removal of iron are compared. It is concluded that the Magnetite process offers considerable cost savings. Other impurities, in particular arsenic, were also removed with the iron in both processes. Cementation at pH 5.2 and 85-90 ¦C with 3.5 g/L zinc dust reduced the levels of copper, cadmium, and nickel to a satisfactory level and subsequent electrolysis in a laboratory cell gave an acceptable deposit of zinc.

Jan 1, 1989

A survey of derelict and active alluvial tin and sapphire mines in the Emmaville area of northern N.S.W. as the first step in a pro- gramme of similar surveys to be undertaken throughout the State by the State Pollution Control Commission is presented. Thirty nine individual mine sites in the study area were included in the survey and an assessment made of the current level of impact on the environment at each site by assigning values of "magnitude" and "importance" to a number of impacting factors. Results are pre- sented in matrix form and mine sites ranked in order of impact "importance". Examples of alluvial tin, underground tin/arsenic and alluvial sapphire operations are discussed in detail and rehabilitation programmes proposed for implementation.

Jan 1, 1976

By Stevens P

The Isa Mine of Mount Isa Mines Limited currently produces 5.4 million tonnes of copper ore and 3.3 million tonnes of silver, lead and zinc ore annually. Of this, 5.1 million tonnes of copper ore and 2.2 million tonnes of silver-lead-zinc ore is produced by sublevel open stoping. This paper summarises the capabilities, operating practices and problems encountered with current production drilling practices used to drill sublevel open stopes at Mount Isa.

Jan 1, 1982

By Dharmappa HB, Sivakumar M

This paper is concerned with two case histories of wastewater quality management in underground coal mines in the Illawarra region. The first investigation briefly presents an analysis of mine water discharge having an extremely high concentration of suspended solids and consistently high barium concentrations, averaging, 14.4 mg/I Barium, over the sampling period. A laboratory study of chemical precipitation processes has indicated that about 91% of barium could be removed by using ferric sulphate and lime. On the basis of the information obtained from the environmental audit process an alternative water treatment and reuse system incorporating 51% reduction in the water consumption with 32% less off-site discharge has been suggested (Thomas, 1995).The second case history is concerned with the storm water management at a mine situated in the Illawarra escarpment where only 20% of the wastewater generated in the colliery is discharged off-site. Computer modelling of the storm water system showed that 75% of the clean runoff becomes contaminated through poor management practices and causes the process wastewater treatment system to fail in wet weather. Suggested improvements include relatively simple alteration to the coal wash filtration dams which are expected to reduce the periods of inefficient operation of these dams by 95%. The use of storm water diversion channels and detention basins can reduce the overflow volumes by 70 - 100 % for a ten year ARI (Average Recurrence Interval) storm event (Wingrove 1996).

Jan 1, 1998

This paper reviews factors involved in the feasibility stage of underground mine project development. Emphasis is placed on the need to first select the best method of extraction and make the most accurate assessment of the expected output even with the uncertainties which may exist in structural interpretation, ground stress, geotechnical factors, and industrial conditions. The subsequent engineering planning should be undertaken from the point of view of the face requirements and is subject to constraints imposed by the method of work and nature of the deposit and, in the case of access, to surface constraints and services.

Jan 1, 1983

By K Inoue

The pressure oxidation of molybdenite concentrates in acidic and alkaline media has been studied. The conditions of the selective oxidation of copper and iron sulphide minerals with a quantitative copper leaching by ferrous-ferric-sulphate solution have been found and explained from the point of view of electrochemical kinetics. The partly oxidised residue consisting of molybdenite and (hydro-) oxide of iron (III) was then decomposed by oxygen in alkaline media. Effects of the main parameters, such us oxygen pressure, leaching temperature, solid-liquid phase ratio, autoclave stirring speed as well as lixiviants nature on the molybdenite oxidation rate have been established.

Jan 1, 2000

Most of the gold reef mined today in South Africa is approximately 1 m in width with slopes about 30 m long. To prevent production interruptions it is essential that the stopes should not be blasted in sections. The shortage of experienced labour and arduous working conditions at the face dictate the need for simple blasting techniques.Hence, a pyrotechnic blasting system of sequential firing is in use at present, although research work to improve this technique is in progress.

Jan 1, 1985

By Liu Q, Siefken T. C, Misra V. N

The bubble size was measured in a laboratory flotation column. The effect of variables such as air flowrate, frother dosage and type, pulp density, particle size and water column height on the bubble size was investigated. The results show that an increase in either air flowrate or pulp density cause the bubble size to increase, while increases in water column height, frother dosage, surface tension or solid particle size cause the bubble size to reduce. Among the frother types tested, MIBC was found to be the most effective in reducing the bubble size.

Jan 1, 1992

The planned extraction of deeper copper ore at Isa Mine has necessitated a review of existing equipment and methods to contain costs and improve working conditions. Mining is in progress for a crushing-conveying system to serve the deeper southern areas of the 1100 Orebody. This system will permit direct tipping of ore to the crushers and conveying of the crushed ore by cable belt conveyor to existing shaft loading facilities, a distance of about 2 km. To develop part of the conveyor drive a new machine will be used, the Robbins MM120 Mobile Miner, a joint development project between The Robbins Company and Mount Isa Mines Limited. The Mobile Miner uses a rotating cutting wheel to excavate headings 3.7 m high and from 4.7 m to 7.5 m wide. To ventilate the deep crusher complexes and associated development at high virgin rock temperatures, a refrigeration plant will be built on surface to reticulate chilled water underground. Bulk cooling of air to the 3000/3500 Orebodies and the southern crushers will be combined with the reticulation of chilled service water to the lower workings of the mine.

Jan 1, 1984

By Worotnicki G, Tillmann V. H

Past experience with fully bonded cable dowels placed as a means of reinforcement in highly stressed crop pillars at the New Broken Hill Consolidated Limited (NBHC) mine indicated such support was not fully effective. Typically overbreak of the crown occurred leaving long lengths of cables hanging from the back stripped of grout and rock with the potential load carrying capacity of the cables not having been fully utilised. This mode of behaviour had been observed in the cable dowelled crowns of three longhole open stopes (EROS) mined to the No. 12 level at NBHC. A system of support with improved mechanism of load transfer from rock to cable and capable of full utilisation of cable strength was proposed for the crown pillars of future Stopes.

Jan 1, 1983

By McLeod RL

The Mt. Morgan mine, located 36 km SSW of Rockhampton, Qld at Lat. 23¦38' S, Long. 1500 22'E, is hosted by a Middle Devonian sequence of acid volcanic rocks and sediments. The Upper Nine Mile Creek (UNMC) prospect, 14 km SE of the Mt. Morgan mine, is in an ap- parently equivalent sequence of rocks. The Late Devonian Mt. Morgan Tonalite separates the two areas. The Mt. Chalmers mine, located 27 km NE of Rockhampton at Lat. 23¦ 18' S, Long. 150039'E, is hosted by the Early Permian Berserker Beds. These three volcanogenic massive sulphide deposits show pronounced similarities in their host rock lithologies and stratigraphic-struc- tural settings.

Jan 1, 1987

Jan 1, 2004

By J Kok

"In some underground mines it has been observed that the primary focus during feasibility studies is to determine the best way to mine the defined orebody. Some studies have been conducted without sufficient consideration of the ventilation and cooling requirements or the risk from exposure to associated airborne pollutants caused by the mining operations.Following the hierarchy of control to manage risk, numerous problems of the ventilation systems in some underground mines could have been avoided if sufficient consideration was given to the ventilation requirements to manage heat, airborne pollutants and leakage during the feasibility study phase. If the constraints and hazards were well defined and understood at the time of the study, efforts could have been made to eliminate or substitute the hazards to decrease the risk. Some of these problems include but are not limited to: primary fan locations heat loads diesel exhaust ventilation design based on the production requirement fire/emergency response strategies.This paper highlights areas in the ventilation discipline that are sometimes overlooked during feasibility studies. It will also highlight the importance of the Ventilation Specialist during these studies. Experience and knowledge of best ventilation practices must be applied in feasibility studies.As a result of adequate consideration to all ventilation aspects in the feasibility study phase, risks will become lower in terms of health, safety, production loss and equipment downtime caused by heat.CITATION:Kok, J, 2014. Feasibility studies – what should be considered in terms of ventilation, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 197–204 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

By M Ljunggren, M Lundh

Dissolved air flotation (DAF) in wastewater treatment as a separation process of submillimetre biological flocs is based on the generation of bubble/floc aggregates. DAF is a complex process but has got advantages, such as allowing a high hydraulic load, compared to sedimentation. A thorough knowledge of the physics of the DAF process is, however, still lacking. This paper will present results of experimental studies on three aspects of significance to the separation process û the flow structure in the flotation tank, rise velocities of aggregates, influence of floc size on the separation efficiency. Flow structure. Measurements were performed in a pilot plant mapping and visualising the velocity field. The dispersion water (bubbles) had a decisive influence on the flow structure due to the effect of the bubbles on the bulk water density. Stratified conditions with a less dense, bubble-containing upper layer and a clear water, denser bottom layer were important for a good separation. A simple model of the stratified flow structure was elaborated making it possible to interpret the function of the aggregate rise velocities. Bubble/floc aggregates. The dynamics of single flocs, bubbles, aggregates were visualised using a borescope + CCD video camera + digital recorder + image analysis. Sequences of video frames made it possible to determine the rise velocities of the single aggregates. These velocities were found to be in the range 1 - 9 mm/s with a tendency for large flocs to have higher rise velocities. Separation versus floc size. The floc size distribution was measured in the DAF process. Data from three different DAF cases showed, that large flocs (> about 100 ¦m) were entirely separated, whereas small flocs experienced a less good separation. It was, moreover, found, that a very significant separation of flocs took place in the very upstream end of the separation zone in a pilot plant case.

Jan 1, 2005

The completion of the 3rd expansion at Queensland Alumina added 725,000 t.p.y. capacity to what was already the world's largest alumina refinery. Rated design capacity is now 2.0 million t.p.y. The expansion was achieved by adding a separate liquor circuit, interconnected with the old at strategic points. This effectively linked a new facility to the existing plant. The resultant problems in controlling plant flow highlighted problems which required considerable operator retraining. The process control problems caused by an inexperienced work force are discussed as are some of the solutions now under study at Q.A.L.

Jan 1, 1974

The detailed engineering of a coal preparation plant is important from the point of view of optimum constructibility, operational security, ease of maintenance, operating costs, meeting environmental goals, safety, plant housekeeping and reduced corrosion and erosion. This paper reviews the several large coking coal preparation plants engineered by Fluor Australia in the past 10 years, and changes and trends apparent for detailed engineering of future plants. Areas of engineering to be covered are coal feed preparation, conveyor design, plant layout, electrics and instrumentation, noise attenuation, erosion and corrosion protection, magnetite handling, rejects and tailings disposal and coal stockpiling and blending.

Jan 1, 1982

The Income Tax Assessment Act ["the Act"] levies tax on a taxpayer's taxable income. At a time when commerce and life were more simple, the calculation of taxable income had some connection with logic and a taxpayer's capacity to pay. However, as a result of successive governments' different views of equity, their perception of avoidance, their needs for revenue and their changing views on capacity to pay, the rules determining the calculation of taxable income have continually changed to the point that logic is no longer relevant. Taxable income now is simply the product of the application of a complex set of rules.

Jan 1, 1990

The mining of Australia's rich and diverse mineral resources has been central to the development of the continent by "Europeans" over the past two hundred years. Mining has historically been encouraged (to varying degrees) by development-orientated state governments (the. managers of largely Crown-owned resources) and since Federation, by successive Com- monwealth governments (which have seen mineral development as a means of generating export revenue to fund predominantly social-welfare orien- tated budgets). This marriage of convenience between governments and the mining industry has to date served all parties well. However, Australia's entry to a new world economic environment at a time that community percep- tions are changing (owing to an education-inspired challenge to "old" values) is challenging the hitherto held assumption that mining develop- ment is always aligned with the well-being of the State and community. Issues such as the type and extent of State/Commonwealth government taxation, resource ownership and control, the environment, land use con- flict, the extent and desirability of secondary processing and infrastruc- ture funding are being debated in the public arena. Opponents of mining in the community are well-organised and are well funded, articulate and more importantly, they have effective communication channels with most governments, irrespective of political complexion. Apart from some television-orientated corporate image building and recent efforts by AMIC, the industry's response to this challenge has been unco-ordinated, poorly directed and arguably ineffective. Professionals working in the industry are concerned about the community's perception of themselves and their industry. Recognizing that the Australian democratic system ensures that, in the large, government at its various levels, is reflective of and responsive to the views and aspirations of people, the industry's response must be wide- ranging, equally articulate and couched in a form which is politically acceptable. New objectives in providing information to the public and its educators must be formulated. Moreover, professionals are looking for new directions from industry leaders. The Institute is well placed to facilitate this process.

Jan 1, 1988