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By Mukherjee R, Bandopadhyay S

Three applications of fuzzy logic in mineral exploration show the possibility of providing feasible solution and allow greater freedom in decision-making processes for geoexploration data which may be ill- defined, biased or where apriori infor

Jan 1, 1998

During the 22 years that Isa Mine has been formally involved in accident prevention, it has succeeded in reducing its lost time injury frequency rate by 70 per cent. At present its performance compares very favourably with that of other heavy industries and in particular that of other underground metalliferous mines. When reductions such as this are recorded, people want to know how it is achieved. No doubt it is assumed that if an organisation can maintain a consistent performance in accident reduction, it must have developed a panacea for the prevention of industrial injuries. This assumption would not be in accordance with the facts in the case of Isa Mine which has achieved its record through plain hard work and plenty of it.

Jan 1, 1975

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

Changes in prices and costs change the mineable grade and the profitabil- ity of an ore reserve. In a static world the grade required for an ore reserve is measured by the ratio: Cost/tonne of ore x 100 Price received/tonne of product and profitability by the ratio:- Price received/tonne of product Cost/tonne of product If the words cost and price refer to average cost and average price over some suitable period, say 3 to 5 years, the above ratios express the convent- ional wisdom of the mining engineer, and assume there will be no change in technology or politics.

Jan 1, 1979

The reliable estimation of ore reserves in mineral sand deposits depends on drilling methods and assay techniques that have been specially developed within the industry. Improvement of these techniques is a continuing process, as variations within and between deposits are highlighted during the actual mining operation. Constant monitoring of metallurgical losses along with mineral production allows comparison of mineral tonnages accounted for by mining, with original calculated reserves. A review of ore reserves in the Jerusalem Creek field from scout drilling in the sixties, through mining in the seventies, shows the progression from understatement prior to mining, to the present when more than two thirds of the reserves have been depleted.

Jan 1, 1979

By Johnson CR, Wilkie G

The aim of the study was to use quantitative mineralogical measurements to predict the processing characteristics of an ore. Samples were taken from a wide range of concentrators processing ores of lead, zinc, copper and nickel. QEM'SEM was used to measure the characteristics of the ore feeding the plant. Concentrate product samples, together with plant operating data were used to give concentrate grade, recovery and grind size information. It was found that the mineralogical measurements correlated well with the metallurgical parameters indicating that these techniques will be very useful for making predictions in feasibility studies and simple plant optimization.

Jan 1, 1989

By Paine G

Kidston Gold Mines commenced mining in 1984 and currently mine approximately 10 million tonnes per annum of ore and waste using a conventional truck and shovel open pit method. The overall mine grade is a low 1.82 grams per tonne.The mineralisation is generally uniform within the ore zones and mining boundaries are staked out from blasthole assays according to pre-determined cut-off grades. Buffer blasting is necessary to minimise post-blast lateral movement of in-situ grade for digging control.The characteristics of the rock currently mined vary widely from soft oxidised to hard unweathered rocks. Blasting problems have been experienced during the initial mining phase in these harder rocks.

Jan 1, 1986

Mineral exploration conducted over a wide area of the State during the period 1960 to 1973 has resulted in the discovery of a number of significant deposits. Base metals, particularly copper, have been of prime interest while, more recently, the search for uranium and coal have assumed import- ance. Expenditure of $27.6 million by companies during the period under re- view has located 580,000 tonnes of cop- per, 370,000 tonnes of zinc, 350,000 tonnes of lead, 24 million Kg of uran- ium oxide and 2,500 million tonnes of coal. A variety of other metals and non metallic and industrial minerals have been investigated in a diversity of geological environments.

Jan 1, 1975

Industrial minerals and rocks (alternat ively called non-metallic minerals) are those- which are economically important because of their desirable physical or chemical properties rather than their metal or energy content. They are divided into nine classes: structural, pig- ments, process aids, ceramics and refractories, chemical source minerals, abrasives, foundry minerals, gem stones, electrical minerals. Development of deposits is influenced by the dominance of marketing,by the required range of products, the-need for specialized process- ing, place value, and the transportation and distribution of high-bulk, low-cost commodities. Evaluation is different from that of base metals because of differences in geological occurrence, sampling methods, testing, treatment, placing a money-value on the material and the importance of export markets.

Jan 1, 1973

By V S. Svinin, V V. Rybin, V A. Maltsev

In large-scale mining, large-sized intermediate pillars, or block-pillars, are generated on the horizon or between closely located mines. These pillars are mined under high rock pressure that results from the stress concentration zones superposition from closely located working excavations. This problem becomes much more complicated if high tectonic stresses occur in the rock mass inducing a rock-burst risk situation. Mining experience gained in mining seven block-pillars at three Khibiny mines in Russia under the geomechanical situation like that described aboveÆ is discussed in detail. It has been shown how safe mine of block-pillars depends on their width, location relative to significant geological failures and uncaved rocks of the hanging wall, the order of pillar recovery, and application of special measures for rock mass stress relieving. Basing on the analysis of the mining experience and special scientific researches, the basic principles are worked-out for safe block-pillar mining under rock-burst prone conditions.

Jan 1, 2000

A career in the mining industry is both challenging and rewarding but comes with some unique complications. Few other industries have such a far reaching effect on individualsÆ lifestyles. Furthermore, few people working within the resource sector could say their job has had no effect on their lifestyle. Mineral deposits in Australia seem to exist predominantly in remote locations like Telfer, Mount Isa and Olympic Dam. With this comes a choice for young professionals; one that is not easy to make, with either alternative often having its pitfalls. This remote nature usually requires professionals (especially graduates and juniors) to choose between a fly-in, fly-out location or relocation to a remote town with less facilities (and some may argue attractions) than their coastal cousins. The challenge for young professionals is to pursue a career that will satisfy their professional goals while developing and maintaining away of life that is emotionally fulfilling.

Jan 1, 2005

Low-grade manganese ore from Sandur, India containing 28.2 per cent manganese and 20.9 per cent iron was roasted with sulphating agents, viz ammonium sulphate and sulphuric acid. The effects of temperature of roasting (300 - 800°C), time (15 - 120 minutes) and amount of sulphating agent (0.5 to 2.5 times stoichiometric amount) were studied. Under optimum conditions, it was possible to extract 92 per cent manganese with 0.5 per cent iron at a temperature of 700°C for 90 minutes duration with stoichiometric ammonium sulphate. Further increase in quantity of ammonium sulphate has marginal effect on manganese extraction.Similar studies were carried out with sulphuric acid, and an extraction of about 87 per cent manganese with similar iron contamination was achieved at a temperature of 700°C for 60 minutes duration with stoichiometric quantity of the reagent. Selective extraction of manganese with respect to iron is discussed.

Jan 1, 1996

By A E. C Peres, J D. Donda

With the aim of producing a concentrate with silica content lower than 1.0 per cent SiO2, laboratory experiments were conducted using a sample of the final concentrate from the Samarco iron ore flotation plant (mechanical cells circuit). The sample contained 3.08 per cent SiO2. This sample was split in two size ranges: >105 ¦m and 2. The >105 ¦m fraction, representing 23.3 per cent of the initial mass, was re-ground to 100 per cent 2 content were obtained. Considering the mass proportions of the two size fractions, the calculated silica content of the combined concentrate was 0.68 per cent, which is considered satisfactory for the objective of this investigation. The major reasons for the higher (0.90 per cent) silica content of the concentrate from the coarse fraction are the presence of silicon in the lattice of goethite and the presence of residual silicious slimes in the pores of porous hematite.

Jan 1, 2005

The Century zinc-lead orebody was discovered in 1990 and contains sufficient reserves to sustain open cut mining at 5 Mtpa of ore for approximately 20 years. It is proposed to pipe mineral concentrate in slurry form 300 km from the mine to the port of Karumba on the Gulf of Carpentaria. The concentrate will be dewatered at Karumba before being transported off-shore to deeper water in a self-unloading shuttle vessel for transfer to export bulk carriers. The four main environmental issues that attracted attention during the impact assessment phase of the project were: the selection of Karumba as the export port, the use of a pipeline to transport concentrate, the risk of concentrate spillage in the marine environment, and aquifer drawdown in the vicinity of the mine. This paper discusses these issues with emphasis on the context of the relationship between the Pasminco Century Project and Gulf communities. Environmental safeguards are discussed, including those that arose out of the negotiations regarding Aboriginal native title.

Jan 1, 1998

By Towsey C. A

Significant advances in regional geochemical exploration techniques have been made over the last 5 years in the search for gold deposits. This has occurred largely by the development of the bulk cyanide ex- tractable gold (BLEG) also known as the Bulk Cyanide Leach (BCL) tech- nique. The technique has been developed and designed for Australian conditions and has two main ad- vantages over the pan concentrate technique preferred by many ex- plorationalists, viz:,. 1. It is designed to collect ultra fine gold common to epithermal and other north Queensland types of gold deposits. 2. The large sample (approx.5 kg) allows very low detection levels, ranging between 0.1 and 0.05 ppb Au. The use of the BLEG technique in exploration has led to the discovery of the Wirralie gold deposit and numerous other epithermal gold prospects previously undetected by pan concentrate and minus 80 mesh (pathfinder elements) surveys in the Drummond Basin.

Jan 1, 1989

In 1975, following a programme of solution characterization and small scale laboratory test work, a pilot plant was constructed to treat waste liquors from the Risdon works. The plant was designed basically to neutralize liquor to a desired pH, and to flocculate, thicken and then filter the resultant pulps. The primary objective was to purify waste liquors to stand- ards set by Tasmanian environmental regulations and at the same time to provide design data for construction of a full scale treatment facility. Waste liquors were divided into two groups, those from the Zinc Plant, and those from the Acid and Superphosphate Plants, and were treated independently. To satisfactorily purify Zinc Plant waste liquors the following reaction sequence was required: 1. Neutralization to pH 10.5 (with aeration for Mn removal). 2. Further reaction of neutralized pulp with Na2S at an addition rate of typically 5 mg of S2-/litre of liquor treated to remove Cd.

Jan 1, 1977

The Regional Development Council has initiated a project that aims to find better ways for further investment by extractive industry companies in sustainable regional and community futures. It will be undertaken through collaborative actions that bring together the resources of private and public sector stakeholders in regional Western Australia.   The broad objectives of the project are to: describe and analyse the current situation with respect to the impediments to regional communities being more self sustaining, assess the effectiveness of the current and possible future levels of investment by extractive industry companies in the sustainable development of communities in regional Western Australia, identify and demonstrate collaborative ways in which extractive industry companies in Australia and other countries can play an enhanced role in sustainable regional and community sustainability through strategic engagement and investment; and confirm the effectiveness of the collaborative measures in delivering sustainable outcomes for regional communities by way of attracting and retaining populations and enterprises in Australia and similar environments.

Jun 1, 2010

By S H. Marshall, H Hutcheson

Conventional batch cell and FASTFLOT pilot plant studies of reverse flotation of coarse marcasite and pyrite (100 - 400 μm) to reduce the sulphidic sulphur content of a rutile concentrate, were undertaken. The batch cell experiments found no significant improvement in sulphur removal with acid wash and copper activation of marcasite and pyrite. Batch cell trials also identified potential difficulties of conventional mechanical cell plants operated at 40 per cent w/w solids. The FASTFLOT 250 B-2 pilot plant trials indicated that with a 0.6 - 0.7 per cent w/w feed sulphur content, target product grade can be met on a routine basis by a three-stage FASTFLOT plant floating coarse marcasite and pyrite. The trials found that 150 g/t PAX dosage and 15 minutes conditioning time are adequate reagentisation for 40 per cent w/w solids feed to the FASTFLOT plant.

Jan 1, 1998

By P Campi, M Dodds

The EastLink project is a 39 km tollway to the east of Melbourne and includes twin three-lane 1.5 km driven tunnels. The hard rock tunnels are being built to avoid passing the motorway through the Mullum Mullum Valley to help preserve the unique flora and fauna in the area. This paper describes the process of transferring the support requirements from the ædrawing boardÆ to the tunnelling face by integrating the temporary support design with the contractorÆs tunnel excavation and support procedures, including sharing of responsibility between the designer and contractor for selection of the support type and the production of a project specific rock mass classification system to enable more objective determination of ground conditions. The methods developed during the design phase incorporated a formal system of reviews, support selection and feedback by monitoring tunnel and ground responses. During construction, the process was implemented using a set of simple documentation and regular structured communication between the contractor and the designer.  

Jan 1, 2008

By Murray G

This paper outlines the processes involved in acid generation from sulphides and the key factors in identifying and predicting time dependent changes in the nature of acid mine drainage (AMD). The initial characteristics of mine water; whether drainage from exposed mining faces, runoff and seepage from waste dumps or seepage from process tailings; do not necessarily reflect the long term potential for AMD. The ultimate quality of mine drainage is a function of the interaction of many chemical, physical, biological and engineering (operational) factors. Techniques are available that can predict the qualitative nature of acid generation and mine drainage quality but accurate quantitative predictions are essentially impossible at the present time. As more and more mining operations exploit sulphide ore, the AMD and acid waste issue will become a. far greater concern. The significance of time dependent factors in the production of acid mine drainage-.is not just restricted to particuL.ar mine sites but needs to be recognised by the mining industry as a whole.

Jan 1, 1988