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By N Strong

Cracow is a high-grade; low-tonnage underground gold mine located approximately 500 km north-west of Brisbane in Central Queensland. It is a steeply dipping, narrow vein, epithermal gold and silver deposit that is accessed via a decline from surface. Cracow is owned by joint venture between Newcrest Mining (70 per cent) and Sedimentary Holdings (30 per cent). The orebodies are 5 m wide on average and the ore is extracted via sublevel open bench stoping. Stopes are extracted to a strike of approximately 25 m before being backfilled with waste. Prior to the introduction of electronics, the mine would remove a small amount of the previous backfill out to create a void, and then begin blasting two to three rings at a time, with the ore being extracted between each blast. This method caused the ore to be blasted onto the waste backfill resulting in dilution of the high-grade ore. It also meant that the extraction of each stope took a number of weeks and numerous blasting events. In the fourth quarter of 2005, the mine struck a geotechnically sensitive stope, where all 20 rings had to be extracted in a single shot or risk possible geotechnical problems that could sterilise the ore. Due to the limitations of NONEL« delay detonators the mine could not fire all the rings in a single shot and needed to use an electronic detonator system to extract the stope. Some unexpected benefits to the mine were increased fragmentation, reduced vibrations, reduced dilution, improved efficiency and improved hanging wall and footwall conditions. After the success of this first electronic shot, the mine has since moved to firing all their stopes with electronic detonators. With electronics the mine has been able to fire much larger blasts, and has in fact moved to firing their blasts in the opposite direction, firing towards the draw point instead of into the waste backfill, thus reducing ore dilution.

Jan 1, 2008

Geophysics is playing an increasingly important role in the exploration industry. In the soft rock scene the application of seismic techniques is basically mandatory prior to any drilling program. Simply, this is because, in a majority of situations, the seismic method is ideally suited to mapping accurately relatively flat lying strata and displaying structures that may host oil or gas. It is worth stressing that seismic methods do not delineate oil or gas but they map well in two or three dimensions. In the base metal arena, geophysical methods used are generally focussed on direct detection methods with the mapping application not often used except in potential fields (magnetics and gravity). The success rate in the last decade has not been good but this does not only apply to the application of geophysics; it really applies across the board of exploration techniques. Both geological and geochemical exploration have not had a success rate commensurate with the funds injected. Basically in the last ten years we have failed as explorers! As explorers we have been negligent in mapping. As geoscientists we have let the basic mapping and observation skills diminish û the old adage æboots on the groundÆ is still applicable but are we doing enough of it? The answer is clearly no. As explorers the huge burden of bureaucracy, eg Government Acts û local, state and federal, safety compliance, environmental compliance, etc has reduced the ægeologicalÆ time dramatically. This has culminated in an over-reliance on quick fix solutions, eg spot the bump geophysics or geochemistry. This obviously simplistic scenario is arguable but there is no doubt in the geoscientific areas we have failed in the last decade to provide adequate geoscientific maps to assist in exploration. This failure could partially be responsible for the current demise of the industry resulting in a reduction in exploration dollars and, hence, people. This trend is seen acutely in the geophysical area where the head count in comparison with the geological fraternity is low. Other trends during this downturn are inevitable as explorers maximise the use of the dollar in exploration and diminish spending on advances in geophysics. Improvements are being seen however in geophysical equipment, although it is considered that the main improvement will be in the interpretation of data. Specifically, the trend will be towards integrating geophysical data into geological, geochemical and spatial data sets producing quality interpretation and providing low risk drill targets. Examples of the current trends in hardware and future directions are discussed below. In interpretive schemes there are very few examples of integrated interpretation but the possible trends will be discussed with limited examples.

Jan 1, 2000

The role of marketing in the development of a new project will be affected by political, commercial and technical pressures. Marketing success will be determined by the ability to predict and react to tomorrow's environment. In the Australian coal industry there is an emerging transition from production to marketing orientation. As a result, greater technical awareness of customer needs will be required. In particular, the industrial product nature of coal markets will need to be recognised. Greater attention will also need to be paid to product options and quality in mine planning. Marketing personnel will become more involved at every phase of the development of a new mine.

Jan 1, 1983

Equilibrium in the reaction H2(g) + [%0] (in liquid copper) = H2O (g) was investigated at temperatures between 1200 -and 1350°C with p(H2Oj/p(H2) ratios between 1 to 15. A semi-microbalance was used for direct measurement of dissolved oxygen in molten copper. Oxygen was found to obey Henry's law under the experimental conditions used. The standard free-energy change for the above reaction is given by Equation 1where 1 weight per cent solution is the standard state for dissolved oxygen.For the dissolution of oxygen in copper according to 1/2 O2(g) = [%0] (liq. Cu), the standard free energychange is given byEquation 2.

Jan 1, 1973

The education system today is turning out potential Mine Managers and Superintendents for the coal industry who are lacking in adequate management knowledge. They are required by the Mining Act to be highly skilled operators who are operations and production oriented. This puts them in much the same category as airline pilots and ships' captains. The real need is for them to be management and profit orientated. Changes over the years in Managers' and Superintendents' roles are highlighted by identifying those professions and vocations with whom they must now work. Comparing classifications in the 1916 award and the current award, and making a comparison between management and mining degree courses, leads to the conclusion that separate degree courses are necessary for future Mine Managers and Mining Engineers. Mine management must become a profession in its own right if optimum profits are to be made from mining in the future.

Jan 1, 1980

By G H. Luttrell

The use of secondary desliming cyclones ahead of froth flotation cells to reject ultrafine (-45 ¦m) particles has become a popular option in the United States for preparing fine coal feeds for froth flotation circuits. In light of this popularity, several experimental studies have been performed at industrial plant sites to develop a better understanding of the impacts of ultrafine desliming on froth cell performance and, ultimately, overall plant performance. These studies included an evaluation of various circuit configurations incorporating different flotation technologies (conventional machines and column cells) as well as different dewatering systems (disc filters, screen-bowl centrifuges, and thermal dryers). The data obtained from these studies indicate that deslime circuits offer several important benefits including lower product ash, reduced product moisture, better froth handling characteristics, and lower capital and operating costs. In addition, case studies conducted as part of this investigation have been used to develop generic guidelines for how deslime circuits may be successfully applied to improve the overall profitability of fine coal flotation circuits for both the metallurgical and steam coal markets.

Jan 1, 2005

The Kundana underground narrow vein gold mine had a recent history of large and damaging seismic events. Following a period of seismic events on 30 July 2001, in which nine miners were temporarily entrapped at depth due to falls of ground in several parts of the decline, the mine operation was required to develop a seismic management system to mitigate seismic risk to the operation. A micro seismic systems and boundary element modelling of mine sequence highlighted large-scale footwall faults and the mining of gold bearing shear veins to be focal structures for seismic energy release between depths of 300 m to the base of mining at 650 m. The integration of seismic data, identification of geological structures and mapping of zones of failed rockmass led to the successful generation of a non linear boundary element model and a seismic hazard strategy. This enabled mine sequences to be assessed daily, monthly and periodically for potential seismic hazards and therefore assigned both economic and personnel risks for the recovery of the ore reserve at the Kundana Underground Operation.

Jan 1, 2005

By Howlett P. F, Courtley S

A problem with secondary breaking at one of the mines of Pasminco Mining led to a study of new rock breaking technologies. Many of the techniques being developed had emerged from the thrust in the USA for continuous drill=break excavation. Such approaches to rock breaking highlighted the applicability of what would normally be classified as tunnelling techniques, to the secondary breaking sector - and possibly the reverse. As a direct result of the investigations for suitable technologies, Pasminco Mining supported the development of two improved rock breaking methods specifically targeting secondary breaking, one of which could be applied to continuous excavation.

Jan 1, 1993

The efficiency with which it is expected that a particular coal may be burnt in a power station boiler significantly affects the value of the coal. Consequently many laboratory tests have been developed to provide data on the combustibility of coal. Computer modelling of coal combustion has also provided insight into limits on coal burn- out. Such modelling suggests that burnout of bituminous coal in a power station boiler will be strongly influenced by physical limits on the diffusion of oxygen to the individual coal particles. Coal chemical reactivity appears to be relatively less important. As a consequence of the diffusional limits, significant improvement in burnout is achieved either by producing less large p.f. particles or by providing sufficient furnace residence time to burn the large particles. Field data from a variety of power stations supports these cn.clusions. Burnout was also found to correlate well with volatile content for a number of coals from widely different sources. This is expected as the high vola- tile coals produce less residual char to be burned by the relatively slow heterogeneous Combustion.

Jan 1, 1987

The major heavy industrial consumers of limestone are the cement, lime'and steel ind- ustries. Each of these requires large quantities of cheap raw material. Other ind- ustries such as glass and chemical manufactur- ing are significant consumers and agricultur- al and constructional activities provide additional demand which is usually more local in its occurrence. Limestone is widely dis- tributed throughout Australia but location in relation to major markets, and transport con- siderations render most deposits of no economic value. Among deposits which are sufficiently close to the major metropolitan markets many must be rejected as being unsuitable on grounds of quality, inadequate size for major.develop- ment, or other reasons such as environmental considerations. The major producing locations are sit- uated in a variety of geological environments. Most have limited reserves and require partic- ular attention to quality control. Planned extraction programmes based on detailed geo- logical investigations enable not only satis- factory grade control but also permit, by the adoption of appropriate quarry procedures, the use of sub-grade material, thus optimis- ing utilisation of the available reserves.

Jan 1, 1976

Perhaps no aspect of the investigation of an ore-deposit is of greater importance to the mining geologist and engineer than a consideration of its geological structure. A thorough understanding of the type, size, shape, and arrangement of any ore-body is essential to the proper conduct of exploratory, developmental, and mining, operations. Significant as these remarks are' in relationship to ore-deposits in general, they become of paramount moment when a complex structure such as the Broken Hill Lode is in question. In this connection the use of the term "lode" as applied to the Broken Hill ore-bodies may terid to confusion of ideas among those not familiar with the field or with the literature pertaining thereto, by reason of the fact that it is generally understood that a "lode" is characterised by simple, tabular form, regular outline, defined walls, and persistent attitude. However, as the terminology is well established by common usage, itsretention appears desirable, and, for the purpose of this paper, the name "The Broken Hill Lode" refers to that complex unit which includes pre-eminently the famous ore-bodies exposed in the workings from the North Mine on the one extreme to the South Blocks (Zinc Corporation) Mine on the other.That the practical value of geological investigation, of the ore-bodies was realised by the Geological Sub-Committee of the late Scientific Society of Broken Hill is attested by the...

Jan 1, 1932

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

By I R. F MacCulloch, K Jones

Pintail Systems, Inc, a Colorado USA based company has developed and commercially applied bioremediation processes for biological detoxification of cyanide compounds in mine waste. Site-specific microorganisms are isolated from spent ore, tailings or process solutions and augmented in the laboratory for cyanide oxidation, denitrification and metal biomineralisation. Biological processes typically treat complex contaminants (cyanide compounds, soluble metals and nitrates) in a fraction of the time of conventional remediation processes. Cyanide is used in microbial metabolic processes as a carbon or a nitrogen source. Biological detoxification processes applied at the end of mine life can end long-term liability and perpetual monitoring and containment. Case studies from commercial application and demonstration programs for the US Environmental Protection Agency will be presented in this paper.

Jan 1, 2004

Development of a small ore body to 137m below surface was carried out in sixteen months driving 610m of 1:5 decline.

Jan 1, 1973

The evaluation programme and procedures develop- ed for Saindak porphyry copper-gold-silver- molybdenum deposits located in an isolated area in an extremely and region of Baluchistan are described in detail. Due to its isol .ted location, far removed from supply centres, harsh climate, paucity of water and non-availability of even unskilled labour, Saindak presented problems for which no ready made solution exist- ed. It is hoped that this Paper may be of some value to those in the LDCs who may wish to undertake similar ventures.

Jan 1, 1988

Peraluminous metamorphic rocks may form from a variety of protoliths by a range of processes. Stratiform bodies of such rocks are relatively common in the Precambrian, but less commonly, also occur in the Phanerozoic. The protoliths of such stratiform bodies may have been regionally deposited chamosite-rich sediments, with varying amounts of clastic component, or may have resulted from the in-situ depositional or diagenetic alteration of volcaniclastic sediments, ranging in composition from rhyolite to basaltic andesite.Stratiform peraluminous metasediments, especially those of low to medium metamorphic grade, and relatively iron rich, may be genetically associated with, or be the host rocks for, a variety of styles of mineralization, especially for the ores of An, Ag, Cu, Zn and Pb.

Jan 1, 1990

Increases in mechanisation and mining at greater depths are leading to additional problems of heat and humidity in many mines. As a result there is now an escalating demand for temperature prediction simulations appli- cable to underground environments. After a brief review of the present situation with regard to world mining and the use of environmental programs, the paper goes on to discuss in moderate detail the mathe- matical modelling of the many parameters that govern the condition of the ventilating air in a mine. The development of a program that gives the temperature distribution for a mine ventilation system is then outlined. The practicality of the program is discussed and the presentation format for users is explained. Simplification of input data requirements and the acquisition of data from other planning programs are an integral part of the commercial application of this program.

Jan 1, 1977

By J Brown, C Roberts

The scope of this paper is to recount the development of segmental linings used in tunnel construction, starting with its inception as an improvement to the brick-lined tunnel approach of Brunel in England and moving through the history and development to the present day, before finishing with a few insights into what the future might hold. The paper also discusses the motivation for the relatively recent move towards replacing conventional steel reinforcing cages with steel fibres and the reasons why steel fibre reinforced concrete (SFRC) is rapidly becoming the material of choice for manufacturing precast concrete segmental linings.

Jan 1, 2008

By McQuade CV, Riley SJ

Acid mine drainage is an unavoidable consequence of some coal mining operations. Typically runoff pH is below 3.5 and at these pH levels heavy metals are mobilised. Leachate from coal reject dumps may require collection and treatment to raise the pH and precipitate the metals before being discharged.A bi-product of coal mining operations at Clarence Colliery is coarse washery reject. At present the coarse reject is deposited above ground and rehabilitated. Adjacent to Clarence Colliery is the Kable's Transport Pty Ltd sand mining operation. It has been proposed that co-disposal of the rejects from both operations may produce a product whose leachate has near neutral pH.

Jan 1, 1998

A review of major mineral processing and extractive metallurgical developments is made and current areas for research are discussed.

Jan 1, 1975