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By McDonald K. J, Flann R. C

A liquid phase sintering (LPS) process for preparing basket anodes from nickel powder has been scaled-up and the innuence of compact green density and sulphur content, as well as sintering conditions (period and syngas now.rate) on the perfonnance of anodes has been evaluated. The product anodes have been tested in an industrial electroplating tank. It is concluded that if anode residues are to be minimised, then with a sintering temperature of 960"C, compact green density needs to be as high as economically achievable (85 - 87 per cent density of solid nickel) and the sintering period approximately 40 minutes. With these constraints, if residual sulphur contents of anodes are to be kept as low as those of commercial anodes, then the sulphur content of the green compacts would need to be less than 1670 ppm. At the same time, it is also found that residual sulphur concentrations as high as 2000 ppm are beneficial to anode pcrfonnancc and not detrimental to the quality of the electroplate. The ability of the LPS process to produce marketable nickel anodes for the electroplating industry is clearly demonstrated.

Jan 1, 1993

By A McCarthy

Spatial modelling has been used to determine potential locations of granite-related nickel skarn mineralisation throughout eastern Australia. It is believed that during granite intrusion, fluid can leach nickel from nearby mafic lithologies and combine with sulfur to form nickel sulfides. Currently exploration for this style of deposit has been limited to the region around the Avebury Deposit in western Tasmania. As the lithologies near Avebury are not unique it is feasible that similar deposits could exist elsewhere in Australia. The weights of evidence spatial data modelling technique was used to evaluate the wealth of geological data available over eastern Australia and included known economic deposits as training data to weight the themes of the model. These weighted themes were combined to create a prospectivity map showing areas favourable for granite-related nickel deposits. Several regions were identified by the model to have good potential to host nickel mineralisation similar to the Avebury deposit. These include areas located throughout New South Wales, Victoria, Tasmania, the Tasman District of New Zealand and, in particular, the Rockhampton region of eastern Queensland. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By N Ross, N Goldup

In recent years the heavy mineral mining industry has started to look more closely at the feasibility of mining moderate to high slimes deposits. During the initial stages of orebody evaluation the primary purpose of the pilot plant is to produce heavy mineral concentrate for metallurgical evaluation. Hence, generally little consideration is given to the disposal of the waste material (slimes and tailings). This paper suggests additional, simple, low-cost, tests that can easily be incorporated into an initial pilot plant operation. With this data a more definitive evaluation of available waste disposal options can be made during the early stages of the project. Thus, permitting better project focus and utilisation of resources. These tests include free settling of slimes, natural slimes drying and consolidation (undrained and drained), tailings stacking angles, and particle size distributions of input and waste streams, etc. The objective and method of each test is summarised, together with its relevance to possible waste disposal options. The results of this preliminary testwork can later be used to expand upon and define further tests for the second phase of pilot plant operations, which will enable a more definitive evaluation of a proposed waste disposal solution.

Jan 1, 2001

Groundwater issues for the mining industry are many and varied. When the depth of mining is below the water table/potentiometric surface, a groundwater æsinkÆ is created which alters the local groundwater flow regime resulting in minewater inflows. Assessment of mine dewatering, mine water balance and wastewater disposal requirements are central to the effective management of water in a mining operation. Each of these issues has a significant groundwater component. Other groundwater issues for mining operations include: water supply, aquifer storage and recovery, the impact on other groundwater users in respect of groundwater levels, bore yields and water quality, and the development of an effective groundwater monitoring network for early detection of impacts and to satisfy regulatory requirements. This paper outlines the techniques involved in assessing groundwater issues for project feasibility, during operation and post closure, and provides an overview of several mine dewatering and water disposal methods. The practical assessment of groundwater issues for the mining industry is illustrated with several case studies of mining projects in Australia, SE Asia and the subcontinent. These are projects to which the author has contributed during a career as a geologist/hydrogeologist spanning more than 25 years.

Jan 1, 2003

Research and Technical Services, Department of Mines Western Australia The nine papers received for this technical session cover a very wide range of hydrological problems in various parts of the world. Three of these papers deal with hydrological predictions for new mines, while three are concerned with the prediction of water chemistry. The three remaining papers deal with gas injection as a dewatering tool, discharge formulae verification and the use of a physical model to predict subsurface strata movement and fracture development due to longwall mining. Hydrological problems in mine planning represent a major risk in many mining operations, booth as a potential life or equipment hazard and a major financial risk. The initial paper selected to review was therefore one by the president of a gold mining company, rather than by one of the specialist scientists, to remind us all that the main reason problems are faced and overcome in the mining industry is usually a commercial one. In one commercial undertaking, the ability to accurately assess future risk is a highly desirable planning tool and hence in mining, the ability to predict the nature and magnitude of hydrological problems is n i-an varxi imnnrfant

Jan 1, 1988

By S Tavelli

This discussion will present a case study in developing solutions to a metropolitan quarryÆs public relations, legal, environmental, and productivity problems. It details an extensive and detailed project to address the blasting practice in a medium sized quarry that is surrounded by residential and industrial zones. The principle work was done over four months duration during the normal production season. It included detailed drilling and blasting audits for baseline information. In addition, geologic characterisation, seismic modeling, correction of deviations from best practices, and implementation and monitoring of precise electronic timing to provide dramatic solutions for the quarry. The quarry is in the near suburbs of a large metropolitan city. It is framed on two sides by residential municipalities and on two sides by industrial zones. At the start of the project, the quarry was in court as a result of the lawsuit by one of the neighboring towns that was suing to close the quarry. The lawsuit had progressed to the advanced stage where in the Judge had appointed an arbitrator to make the decision of continued operation. This arbitrator was to observe our progress and recommend to the Judge the disposition of the case.

Jan 1, 2004

In six deep hard coal mines situated in the coal district of the Saar and Lorraine, Saarbergwerke AG produce annually 9 to 10 million tons of coal. The coal is either coked or fired in power plants. Comprehensive planning work is done for the producing coal faces, 15 stone drifts and 60 seam headings. The computer can assist in drawing up the short- and medium-term planning by taking over, on the one hand, work done so far by hand and by supplying, on the other, additional information. The computer can draw up time schedules, can do quantitative calculations, can draw up plans for the em- ployment of manpower, machines and other equipment, and can calculate cost and earnings. It is ensured that all part plans are always adjusted to each other. Because of the volume of work involved, planning in this form and extent becomes possible only by the computer. Especially with the periodical continuation of planning, the new system facilitates the work to be done. The ideas of the planning engineer are and remain the basis of all planning work and the computer gives him an aid to assist him with calculations, report writing and feasibility studies.

Jan 1, 1977

By Opitz E. A

The integration of environmental and permitting strategies into development has become a routine part of doing business for the international minerals industry. Paralleling the development schedule with the environmental and permitting schedule is critical to ensuring that design recognises environmental constraints and that the environmental and permitting program has the right focus and achieves the objective of obtaining workable permits that reflect the project design. Regulatory issues including the law of and controls established by the country the project is situated in, the requirements of international financing institutions, international politics and the role of environmental groups and the particular precedents and processes established are all important issues that must be recognised and incorporated into the permitting program by the developer. Technical issues including collecting early environmental data during exploration, establishing hydro-meteorology equipment, baseline data gathering, and getting good environmental engineering information as a part of feasibility and design are also critical issues to the success of a project which are under the direct control of the developer. Finally tying all of these issues into a single integrated strategy under the direction and control of a nominated team is necessary to maintain focus and achieve results.

Jan 1, 1997

Australis Mining N.L. operates a continuous mode carbon-in-pulp (CIP) gold plant, processing sand and slime tailings from previous gold mining operations in the Norseman area. Plant design is that of conventional countercurrent contact between pregnant pulp and activated carbon. Gold desorption is achieved by the Zadra process using near boiling tempera- tures and atmospheric pressure. Process water is drawn from nearby Lake Cowan (saline). The plant operates at, or above, design specification of 400 dry tonnes per day. This paper describes the plant design and operating processes utilised in optimising throughput and gold recovery. TNTDnPTTnmTnM Favourable world gold prices and substantial reserves of sand and slime tailings prompted Australis Mining N.L. to construct a gold extraction plant during 1981. The projected plant throughput was set so as to complete treatment of available tailings over a three year period. Metal- lurgical tests indicated that, with a regrind facility satisfactory gold recovery could be achieved using a countercurrent CIP process. Reflecting the entry of Australis Mining N.L. into its first large scale treatment operation, the plant design emphasised simplicity but effectiveness of Operation.

Jan 1, 1982

The Ida Valley in Central Otago is one of series of parallel basins filled with freshwater sediments. The basins are in fact tectonic depressions superimposed on NE trending grabenlike structures which occur in the area and are the result of block faulting possibly initiated in Cretaceous times and concluded in late Tertiary and early Quaternary. In Central Otago this tectonic event affected metamorphosed rocks belonging to the eastern facies of the New Zealand Geosyncline and collectively known as the Haast Schist Group. These rocks constitute the basement and the shoulders of the tectonic depressions. The Ida Valley occupies the depression wedged in between the Raggedy Range to the NW and the North Rough Ridge in the SE. The valley is approximately 38 km long, 3 to 7.5 km wide and is drained by the NE flowing Pool Burn, which meets the SW flowing Ida Burn. The resulting unified stream flows into the Manuherikia river which drains the next door depression to the NW. The present work deals with the Ida Valley basin and more specifically with the geology studied within two Prospecting Licence areas held by Gold Mines of NZ Ltd on the southeastern flank of the valley.

Jan 1, 1977

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 Muir D. M

Highly saline process water has a number of implications for the CIP process during the leaching, adsorption and recovery of gold. The reduced oxygen solubility in saline water can seriously reduce the rate of gold leaching, while dissolved oxygen meters do not necessarily reveal actual oxygen concentrations in saline water. High levels of magnesium in the ground water necessitate operation at lower pH (-9), with the potential for greater cyanide loss via HCN stripping. In addition increasing salinity renders viscosity modifiers largely ineffective.The adsorption capacity of aurocyanide onto activated carbon is improved with increasing salinity, but misleading results can be obtained in assessment of gold loading kinetics of plant carbon samples already loaded, or partially loaded, in saline water if subsequently tested in fresh water. Elevated chloride levels in the Zadra elution process can cause severe anode corrosion in the elecuowinning cell. The Anglo elution process is tolerant to only slight increases in water salinity, but elution times can be reduced by ethanol addition. Care is required in carbon regeneration, as salts can catalyse carbon decomposition as well as increase kiln corrosion.

Jan 1, 1994

By Vernon PN

The Eossing Uranium Mine is a high tonnage low grade open pit operation using acid leaching for uranium extraction and ion exchange and solvent extraction for solution purification. Advanced technology, much of it computer based, has led to major economies that have contained operating unit costs over the last four years in the face of double figure inflation. An improved ore reserve block model and mine planning system have achieved a considerable reduction in the stripping ratio. Drilling and blasting costs have decreased some 25%, mainly by the introduction of heavy ANFO explosive. A centralised computer control centre for the metallurgical plant has increased labour productivity resulting in improved process control. The all-staff workforce is united with management in the objectives of creating a safe, healthy, working and living environment and a prosperous company, capable of contributing to the wellbeing of the nation and the shareholders. This situation has been brought into being by an equal opportunity policy coupled with a management system emphasising open two-way communication through all levels in the organisation. The success of this policy is highly apparent in the morale and productivity of the workforce.

Jan 1, 1986

Subsidence data resulting from longwall mining in the northern part of the Newcastle Coalfield of New South Wales has been reviewed. Themain factors influencing subsidence variability in this area (apart from width/height ratio) are strong bridging strata, the effects of the first major goaf fall, mining direction and depth of cover. In 1987 the NSW Department of Mineral Resources produced a guide to subsidence prediction for the Newcastle Coalfield which is still widely used. The current study shows this guide to be no longer appropriate for this area. An alternative prediction curve, incorporating more recent data, is suggested.

Jan 1, 1998

A brief introduction is given of the scale and of some special features of South African gold mining; it is noted that great depth of mining and narrowness of the reefs, and hardness and abrasiveness of the rock are the main sources of the problems of the industry. The most inhibiting problems are: Excessive rock pressure occcurring in conjunction with rockbursts, hot and humid working places due to high virgin rock temperature and auto-compression of the air, and low level of productivity. Conventional solutions applied ordinarily in mining do not promise to eliminate, or even alleviate, these difficulties.

Jan 1, 1985

BlIP Minerals is a large, diversified, international mineral producer. This paper describes the company's operating strategy, and identifies the role of mineral processing in this strategy through three examples: the column flotation installation at Escondida in Chile, the leach-SX-electrowinning plant, proposed for Escondida, and the whole-ore roasting process being constructed for the Syama gold operation in Mali. It is concluded that the application of appropriate and sometimes novel mineral processing technologies can achieve significant benefits in reduced operating cost, improved product quality, and in some cases the exploitation of previously uneconomic deposits, thereby providing strategic advantages to the company.

Jan 1, 1993

By B Madeja-Struminska

The method of evaluation of the approximate temperature of arising spontaneous fire centre and time of coal self-ignition is presented in this paper. The method uses BystronÆs (1997) model of coal self-heating and measurement of carbon monoxide concentration in the mine air outside the fire centre. Knowledge of the spontaneous fire centre temperature and time of fire beginning allows for more accurate analysis of the fire hazard in the coal mine and allows for adequate time to undertake special fire prevention actions. The method is illustrated by an example from Polish mining practice.

Jan 1, 2005

By Keren Z, Huanguo G, Jlchuan Q

In this paper, the authors introduce a new flotation technique, a double collection flotation precess, which succeeds in separating feldspar from quartz effectively in weak acidic medium (pH = 5-6). In the presence of sodium hexametaphosphase(HMP), sodium oleate selectively improves the floatability of feldspar in the first collection step. Dodecyl amine- hydrochloride is used as collector in the second collection step to separate feldspar from quartz. The flotation tests with pure minerals as well as artificial mixture give out satisfactory results. The mechanism of reagent effect was investigated briefly, which is helpful for understanding the Process.

Jan 1, 1993

By Henderson J, Ward RG

Dissolved oxygen has been measured directly using a rugged, reliable, accurate electrochemical probe system developed for steelworks application by B.H.P. Central Research Laboratories. Furnace measurements show that the steel is generally supersaturated with oxygen and that oxygen contents vary considerably from heat. to heat. Ladle measurements also show considerable heat-to-heat variations. Analysis in terms of ladle deoxidation chemistry differentiates between carbon monoxide controlled and manganese silicate controlled oxygen levels. Deviations from these levels are sometimes due to aluminium present in other added ladle alloys but in some cases the plant applicability of laboratory derived equilibria is questionable.

Jan 1, 1972

By Jensen B

The approach of using the Coward Triangle for the analysis of flammable mine gas mixtures has been examined for its application, to the flammability of coal dust/gas/air mixtures. Explosible lean limit and rich limit concentration data for dust/methane/air mixtures are examined and illustrated using co-ordinate geometry. It is concluded that a three-dimensional envelope representing hybrid explosible mixtures can be drawn. The dimensions of this explosive zone will vary with the characteristics of the coal dust and the gaseous composition of the mine atmosphere. Further research is needed to establish these dimensions for important mined seams.

Jan 1, 1994