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By P Gy

When it comes to sampling theory, a bad sampler is a bad sampler, no matter what, and a sampler is either bad or good. It also is of critical economic importance to tell and understand the difference, especially in a metallurgical plant. In this paper, the grand principles of Sampling Theory are first recalled, then the most popular types of sample cutters for plants are critically reviewed. It is concluded that the industry has a lot of progress to make in that direction, although improvements usually pay for themselves very quickly.

Jan 1, 2002

By Groudeva VI

The biohydrometallurgy of gold is based on different processes which could be grouped into four main groups (Attia, Litchfield and Vaaler, 1985; Karavaiko et al, 1988; Groudev, 1990): 1. bacterial oxidation of gold-bearing sulphide minerals by chemolithotrophic bacteria to facilitate the subsequent chemical extraction of gold; 2. solubilisation of gold from oxide ores by means of heterotrophic bacteria; 3. recovery of gold from solutions by biosorption; and 4. microbial modifications of the surface of gold-bearing sulphide minerals to improve the subsequent gold concentration by physical dressing methods (eg flotation, oil agglomeration).

Jan 1, 1993

Offshore petroleum development involves massive capital expenditure and financing demands, with the main participants being large international oil companies and State owned enterprises. Types of project oriented financing include take-or-pay contracts, throughput agreements, and production payment financing. The main project finance credit aspects are revenues, investment budgets and cost over- runs, reservoir, political and other risks and special problems such as weather and corrosion in the North Sea. A variety of documents is required and a mix of equity, export credit and Euro-market financing will typically be included in the financing.

Jan 1, 1983

The three main types of iron ore deposits in Australia are bedded, massive and residual. Some character- istics of iron ore, important in its process behaviour, are related to its mineralogy which is a result of its geological history. World iron ore resources are extremely large but there are problems in quantifying re- serves, defined as that part of re- sources from which a useable commodity can be extracted economically. The relationship between the discovery and exploitation of iron ore resources and the process of industrialization is examined in historical and present day contexts.

Jan 1, 1976

By Larsen E. R

We discuss the concept of optimal cut-off grade policies and their advantages in terms of maximisation of net present value of mining operations. There are indications, however, that such optimal policies are not widely used in the mining industry. In order to explore why this is the case we identify a number of stakeholders who may have diverging interests in the operating policies of a given mine. These various interests are mapped and a number of important relationships are explored in a large qualitative systems dyanmics model.

Jan 1, 1995

Cordeaux Colliery is more logically sited than the historic escarpment Corrimal Colliery, on the same reserve. At Cordeaux the modernisation of mine plans and equipment and the introduction of high production longwalls have created a record achieving producer of both steelmaking and export coals.Further changes achieved have been in employee related attitudes and performance, enhanced by business strategies and total quality control and particularly benefiting from innovative employee input With this present example of co-operative effort Cordeaux Colliery will continue to improve through management of total quality. resources, development rates and customer satisfaction.

Jan 1, 1991

By McLaughlin R. G, Brammer R. A J

King Island Scheelite had been using dealer modified front end loaders for two years when in 1974 it started to increase production. Suppliers were then quoting long deliveries for underground diesel trackless mining equip- ment, and the Company was forced to modify surface machines which had become redundant as production from the open cut phased out. The results were generally successful and encouraged further adaptations. Drill jumbos excepted, the Company now uses only converted surface machines in areas worked by diesel engined equipment and for all support and auxiliary functions.

Jan 1, 1977

By McKendry J. B

Gretley Colliery is situated at Wallsend, a suburb of Newcastle in New South Wales and is owned and operated by the Newcastle Wallsend Coal Ccnpany, a wholly owned subsidiary of Peko Wallsend Limited. The mine has been an efficient bord and pillar producer by industry standards. However, its continued economic viability was threatened because the bulk of remaining reserves lie in more difficult mining conditions and are of poorer quality. Alternatives were examined to improve productivity and allow Gretley to become more competitive in the current difficult market Environment.

Jan 1, 1988

By Lunarzewski L, Truong D

Although there are sound principles used in the world recognised methods of gas emission prediction, results based on these methods applied to several Australian longwall extractions have yielded unacceptably high discrepancies. With the development of mining in new seams and at higher rates of extraction, the need has grown for a methodical approach to predicting gas emission levels specifically for local Australian mining conditions. Such an approach is developed from results of recorded emission readings during longwall mining at Appin and Pacific Collieries over the past 6 years.

Jan 1, 1988

Confirmation of significant mineable reserves of high grade silver ore at Elura Mine has led to the development of a high cost, high recovery mining system. At the contact of oxidised and sulphide ores lies a supergene zone of enrichment which has provided a contrast, not formerly imagined, to Elura's primary development and stoping operations. Because of the soft nature of the ore, intense ground support practice has been combined with a panel cut and fill continuous mining system to extract a reserve of small, but most valuable Proportions.

Jan 1, 1988

By Kovscek P. D, Thimons E. D

The Bureau of Mines equipped a longwall shearer with a water- jet-assisted cutting system and measured dust levels during the cutting of a simulated coal block. The block was cut dry, at a conventional water spray pressure of 1 MPa and with water-jet-assisted cutting pressures ranging from 7 to 40 MPa. At water pressures of 20 MPa and higher, dust concentrations were reduced by as much as 85 % via water-jet-assisted cutting in comparison with conventional water sprays. This reduction was achieved without any increase in the water flow rate.

Jan 1, 1988

By Brouwer G, Shaw J

As South African gold mines go deeper, and improved and more uniform working condi- tions are required, ever larger amounts of refrigeration are needed. At the same time new and more suitable cooling equipment is becoming available for use with new mining layouts as well as on existing shaft systems. The advent of the large diameter rotor screw compressor has meant that there is now a machine available with great flexibility in performance and construction for efficient underground use. The first installation using this type of machine is described.

Jan 1, 1988

By Pinn N

Geosynthetics is an all encompassing word to describe a number of man-made products usually from hydrocarbons which are used in conjunction with the soil. The specific products are:Geotextiles Geomembranes GeonetsGeogrids GeocompositesIn mine establishment and associated construction work, Geosynthetics have proven to be successful in a wide range of applications. For example, geotextiles are now used to assist with the establishment of access roads, site preparation, haul roads and in connection with the construction of embankments for storage ponds and dams as well as for general hydraulic and foundation engineering problems.

Jan 1, 1990

By Miller RJ, Eager DT, Lama RD

For safe and efficient mining operations, it is essential that environment and equipment status be monitored. A system that gives quick access to status at any given time, and also permits quick analysis of their history, is required. Such a computer based monitoring system has been installed at West Cliff Colliery.The system is based on 2 super mini computers. Three major sub-systems monitor conditions in the longwall operations, environmental conditions in the intake and return roadways, status of the underground and surface installations, and mining and transport equipment.

Jan 1, 1985

The mining and resources industry in general has relied on macro separation technologies (greater than 1 micron) through processes which include: ò sedimentation ò flocculation and coagulation screening and filtration ò absorption ò magnetic separation ò chemical leaching and precipitation Essentially, these processes and technologies provide the industry with an effective arsenal to handle most separation requirements to date. Dewatering of solutions is one of the most significant requirements of the resources industry, as practically all mining endeavours use water in their process for leaching, extraction, cooling, dilution or for potable drinking water.

Jan 1, 1989

Coal Mining machinery has undergone enormous changes in design and complexity of controls in the past 10 years. Specialised, high productivity equipment has been manufactured in Australia, in sufficient volume, to satisfy the local mullet needs.Local manufacturers face greater challenges from overseas competition, as well as increased customer demands to improve machine performance, productivity, quality, reliability and safety. In order to meet these demands now and in the future, it will be necessary to review work practises, and restructure production and quality systems to incorporate the latest principles and philosophies.

Jan 1, 1991

By Hunter T. C

The wirebar furnacing and casting facility commissioned in 1970 at Copper Refineries Pty. Ltd. (CRL), Townsville, comprising a 70 tonne/ hour ASARCO shaft furnace and a Walker type casting wheel, contained several unique design features. Since commissioning, effort has been directed at improving metallurgical control of the casting process. This has resulted in the identification of optimum mould lubricant properties and the use of continuous on-line measurement of molten metal oxygen content. Casting defects such as cracks and surface porosity are readily explained and controlled using these techniques.

Jan 1, 1977

Sampling and analysis of mineral deposits need to be executed without fear or favour of financial or personal impacts. Examples are given to illustrate the effects of departures, witting and unwitting, from correct use of appropriate techniques and/or equipment with emphasis on exploration and mining of porphyry copper deposits of the Pacific Rim. Some of the results of errors on the low and high sides of true value in exploration, resource or reserve estimations and in production caused by sampling and/or sample preparation mistakes, faulty practices, equipment and/or analysis are considered.

Jan 1, 2004

By D M. Menne

This paper is intended to give a general review of current gold extraction technology for free-milling or non-refractory auriferous ores. Fundamental process concepts and some of the differences between the current technologies is referred to. Typical flowsheets and layouts are provided and it is demonstrated that technology for extracting free-milling gold is relatively simple. For environmentally sensitive areas such as encountered in New Zealand relevant cyanide decay and destruction technology is also discussed. Brief mention is made of some likely future innovations. Finally reference is made of New Zealand's previous significant contribution to gold extraction technology. These contributions were pioneering ranging from the cyanide leaching of gold to adsorption by carbon and precipitation by zinc. New Zealand has not allowed its potential gold projects to develop at a rate commensurate with the rest of the world thereby stifling its renowned innovative approach in this technology. It is time for New Zealand mining to recognise its unique opportunities in developing gold extraction technology and again take a rightful place in leading the way.

Jan 1, 1986

Owing to the increased consumption of sulphuric acid; Australian manufacturers have, from time to time, been seeking for a satisfactory source of sulphur that would make them independent of foreign supplies.Some years ago a considerable amount of acid was obtained from the roasting of Spanish pyrites. This ore, in 1913 or thereabouts, cost 16s. per ton f.o.b. Huelva, and freight to the eastern seaboard of Australia was about 20s. per ton. As the ore contained 48% to 50% of available sulphur, it was costing roughly 9d. or 10d. per unit, and, in addition, the cinder, after roasting, was a product of considerable value to smelters, containing as it did a high percentage of iron suitable for fluxing, and appreciable values in silver and gold.

Jan 1, 1925