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Inevitably the 'post-boom' era has changed the emphasis of many mining companies away from new project development and expansion to optimisation of existing operations. However, regardless of the project, high quality ore characterisation will remain of the utmost importance. In the case of new project development the need to understand the breakage characteristics will remain as important as it has always been. In optimisation projects, however, where it will be required to get the very best from existing comminution circuits, accurate geometallurgical modelling will take on an increasingly important role. However, these requirements, in both new development and optimisation projects, are likely to be at odds with budgets as these will be tight. Hence obtaining the best value for money will be essential. This paper discusses the elements that need to be satisfied for ore characterisation programs to be successful. Some of the issues covered will be: ore variability and sample selection, test precision, problems with the use of non-standard testing equipment, and the value of databases.

Jan 1, 2009

The paper reviews recent valuations of mineral properties, many of which are at an early stage of exploration. The various methods used are outlined. The problem of comparing, in terms of whether it is fair and reasonable, a highly subjective opinion of the present value of a portfolio of exploration tenements with a vendor consideration, the real value of which, in most cases, lies at some indeterminate time in the future because of the application by the Australian Stock Exchange (ASX) of escrow conditions, is highlighted. Examples are given of some of the questionable logic used by consultants in handling this difficult issue. A proposal for revision to current flotation and listing practice which, the author believes, would circumvent the problem and at the same time provide better protection for the investing public is offered for Consideration.

Jan 1, 1994

Milling Practices Ore is direct tipped into a gyratory crusher and crushed to minus 209mm and fed to stockpiles for the blending of grade into the mills. Secondary and tertiary crushing reduces the mill feed to minus 12mm. Mill feed is a blend of breccia and porphyry ore into two primary mills with the overflow to a regrind mill and then into the leach tanks, followed by a conventional counter current carbon in leach circuit. Underflow from the cyclones feeds back into the primary mills for additional grind. An unusual feature of the Mt Leyshon milling circuit is a desire to produce scatts. The scatt by product is the polished base rock of the Mt Leyshon Breccia clast and contains little grade. These scatts are produced because of the additional time and energy required to produce a proportionally small quantity of gold. The residence of these scatts in the mills decreases the mill feed rate. Scatts account for twenty percent of the mill feed and are screened from the discharge of the primary mills.

Jan 1, 1990

By R H. Boffey

The Osborne copper-gold deposit was discovered in North-West Queensland in 1989. Underground production activities commenced at Osborne deposit in April 1996. This paper will examine technical and operational aspects of the underground mine during its development to a 1.2 Mtpa operation . Technical aspects discussed include geology, mine design and mining methods, equipment fleet selection and capital infrastructure. Operational aspects discussed include the evolution and performance of the integrated work teams that are utilised at Osborne to perform all mining and maintenance activities.

Jan 1, 1998

An extensive railway construction prog- ram in the People's Republic of China has required the excavation of many tunnels in difficult ground, particularly in mountainous regions. Conclusions drawn from case histories permit guidelines to be formulated as to the optimum location of tunnel alignments in faulted and folded terrains, and also in karst regions. Geological factors adversely affecting durability of tunnel linings can be minimised by adoption of appropriate construc- tion practices.

Jan 1, 1987

To enable AN-FO .tòo' be used on an equal .weight basis wish Nitro Gl reerin.e expl3oòsives r smaller diameter bore holes became necessary With consequent modifications to drill steel and burden on holes, De't'onation of AN-FO "in small diameter holes proved successful' both with 'and without primer charges but some altorat-ions were required to. adopt Anolodeòr.s to the smaller -holes, Important factors in training all operators In the new charging method were the retention of imp-,cved, fragmentat'ion, avoidance of excel ive ove:break and keeping wall rock dilution 'to an absoluato mi. iArurle ò The ò successful storage of Ammonium 14t-rate in c"!ime.tic conditions 'with daily'.-' temperature fluctuationc above and below the critical' 90¦F, has. been "achieved,

Jan 1, 1964

By Chisholm J. M

Why go to the CIS? The vast mineral potential of the Commonwealth of Independent States (CIS) has long been recognised, but it has taken the lowering of the iron curtain to open up the region to serious mineral development consideration by the Western World. The advent of a free market economy and the emergence of the Independent States with pressing needs for foreign investment has led to a greatly improved investment climate. Coupled with the desire for some of the more entrepreneurial resources companies to head the wave of investment to the region, this sequence of events has promised a great deal, but delivered only modest progress to-date. Potential gold project development has provided the major focus, for three reasons: the region is highly prospective for gold, gold projects tend to have a relatively lower start-up capital cost compared to base metal and fossil fuel projects and finally bullion or refined gold is more readily transportable and easier to sell.

Jan 1, 1996

As mines become deeper, the problems of heat in the workplacebecome more acute. An important response from the industry hasbeen the widespread adoption of microclimate cooling such asair-conditioned cabins. However, not all work in mines can becompleted from inside an air-conditioned cabin, and in any event,it is still important to keep the ambient air in the mine outside ofany microclimate to a safe temperature. An important method forbringing workplace temperatures under control is the appropriateuse of refrigeration. The application of refrigeration inmechanised mines has been recently described (Brake, 2001;Brake and Fulker, 2000). This paper provides an overview ofsome of the important engineering considerations in thespecification and selection of mine refrigeration plants. Thepurpose is to provide a basic understanding of refrigerationprinciples, practices, terminology, hazards and opportunities formining engineers or other personnel who may need to beinvolved in the introduction of refrigeration onto a mine site.

Jan 1, 2001

Spiral separators have been used to treat heavy mineralsands in Australia for some 35 years. During the last five years the logical extension of this technology has been torecover cassiterite from alluvial deposits. Plants incorporating spirals are already operating in Indonesian andAustralian tin mines. A more fundamental understanding of the design of spiral separators has recently led to their use in other mineral treatment plants.In particular, the treatment of alluvial gold and fine coal has been most successful. The new generation of spirals that has been developed to treat these minerals is more easily operated than other competing processes and is therefore ideal for new mine situations.

Jan 1, 1986

An intensely sheared and mineralisedIzone occurs in the Quartz Dolerite Greenstone (or Younger Greenstone) mass on, the western limb of the Kalgoorlie Syncline. This zone comprises the western part of the Golden Mile and has produced the greater part of the 33,000,000 ounces of gold produced to date from the main mining belts. A study of.th e general geological and structural features gives rise to the expectation that the lode shear system,will continue southward on a pitch similar to that of the maln syncline whose axial plane may be referred to as the "Boulder Dyke". Although payable ore has recently been found further south than previously, the expectation of large quantities extending southward from the present mining areas is Problematical.'

Jan 1, 1964

The Geograph is a revolutionary seismic system involving special techniques in combining the use of FIT magnetic tape with shock wave echoes created by a weight dropping system.The idea of- weight dropping as a- source of seismic energy is not a new,.,oxie. Records 'indicate òa pos'sihle use of falling weights as early as .1929. 'Dr. Burton McCollum began his experiments in 1938, but it wasn't until 1951 that the method was first proven useful.The first weight dropping crew began commercial operations in Edwards and Sutton .Counties of West Texas in 1953. By 1962, more than '40 weight drop-ping.crews have come into existence with operations in the United States, Canada, Algeria, Iraq, Argent na,òSpanish West Africa, Tunisia, Qatar, Niger Morocco and Libya by most major oil companies and larger independent oil companies. .

Jan 1, 1962

Most mining projects will involve some level of financial markets price risk. This is because commodities are generally traded in $US. The project will also incur costs in $A and if based in Australia will seek to generate a return in Australian dollars. Therefore the project faces commodity, foreign exchange and interest rates risk. As a business you may wish to maintain these risks within your business. However if the project requires financing to be provided then the financiers will want to ensure that there is a level of certainty attached to the cash flows to support the debt repayments. This is achieved by hedging the financial market risks. Traditionally the hedging process has been based on underlying assumptions within project models, which incorporate views on the direction of the underlying price risk. These views can be formed in an ad hoc manner. Gathering information from a variety of sources including economic forecasting and modelling, technical analysis, seeking market expert views. However, given the historical accuracy of such forecasts locking into long-term fixed hedging arrangements can create an inflexible environment that can restrict the opportunity to benefit from the underlying volatility of financial markets.

Jan 1, 2003

By D Manhire, G Hogan, M Ryan, S Whiteley

Site restoration at the L&M Mining Limited alluvial gold mining project at Waikaka near Gore, Southland is described. In 2000 mining operations started to recover alluvial gold beneath historical dredge tailings over 244 hectares in the flood plain of the Waikaka Stream. The project had an eight to nine year mine life but was prematurely closed in 2002 because of economic considerations. Restoration of the site back to pastoral farming, with shelter-belt and amenity tree, shrub, and wetland plantings is described. Dealings with the landowners and regulating authorities are addressed in the paper.

Jan 1, 2003

By Stubbs B

In conjunction with Charles Copeman, we have arranged the presentation of a paper by Charles with a support paper by myself presenting alternatives to currentaccepted legal concepts involving the ownership of minerals by the Crown and the absence of ownership in any minerals or entitlement to benefit therefrom by the owner of the land on or under which the minerals occur.2. The current situation has its historical route in the concept of gold and silver being royal metals and belonging wherever situated in the Kingdom to the King and it is submitted it can be'seen as being archaic in nature perhaps even feudal and perhaps worthy in this day and age of reconsideration.Our purpose in these papers is to present an alternative view supported by argument challenging the present system and hopefully, creating room for comment and interchange amongst those involved in the industry. My solutions are not Charles Copeman's solutions and vice-versa. However, we do share a common belief that the present system may not be the best system.

Jan 1, 1990

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

Today's emphasis on the enterprise bargaining process must be seen as an opportunity for organisations to further develop occupational health and safety standards at work. In particular, this shift from a centralised industrial relations system to employer, employee bargaining, presents organisations with an excellent opportunity to develop OH & S at the `shop floor' level. This is despite real difficulties in presenting hard data on the cost benefits. Unfortunately, examination of enterprise agreements ratified by the Australian Industrial Relations Commission (AIRC), show that less than 32 per cent contain provision for occupational health and safety. Those addressing the issues of occupational health and safety have included segments such as: ò rehabilitation activities; ò a new emphasis for workplace occupational health and safety committees; ò formalising procedures related to hazard identification and control; ò the use of personal protective clothing; and ò occupational hygiene and health monitoring issues. For example, an enterprise agreement reached between CIG-Gases and their unions, included clauses which commit employees to attending ten safety meetings and two work place inspections each year, in order for them to receive any further pay rises.

Jan 1, 1995

The relative importance of magmatic and metamorphic fluids in Archaean gold mineralisation has long been a subject of debate. Computer simulations can be used to explore the interaction between competing fluid flow drivers, thus providing insight into their role in mineralisation. This approach has been applied to Archaean gold mineralisation in the Yilgarn craton, Western Australia. A simple model representing regional metamorphism in a granite-greenstone terrane indicates that fluid produced during a regional metamorphic event in the Yilgarn was unlikely to have been involved in mineralisation, because it would have escaped from the crust long before the main gold event. Another model illustrates the competition between magmatic fluid production, convection, and deformation. The model shows that the timing of deformation relative to fluid production is important in determining the fate of magmatic and metamorphic fluids, and hence their potential to play a role in mineralisation. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Conceptually coal reserve assessment is simple but in practice it presents many problems. These arise from the origin and geological history of coal seams and from the diverse nature of the coal itself. The suitability of a coal for a particular use depends upon its type and so sheer quantity of reserves does not guarantee the adequacy of coal reserves for all requirements. Codes have been formulated to counteract the effects of subjectivity in reserve assessment. The code for calculating and reporting coal reserves published by the Standing Committee on Coalfield Geology of New South Wales has wide acceptance but the Committee itself recognises that it has shortcomings. Currently the Committee is engaged on the commendable but difficult endeavour of formulating a code that will meet the needs of scientific rigour and professional and commercial ethics and that will allow the specification of an assessment method without constraining it. It is generally agreed in the coal industry that the assessment of coal reserves can not conveniently be incorporated into codes formulated for other resources.

Jan 1, 1979

This paper describes some experiences in the design of flotation reagent schemes for the efficient flotation of complex gold ores containing free gold and/or gold associated with easily flotable sulphide minerals such as chalcopyrite and bornite. Historically, the design of gold flotation reagent schemes has been based primarily on experiences using high dosage levels of water soluble charged collectors such as xanthates and dithiophosphates and carefully controlled regions of pH. This approach has been effective with gold associated with complex sulphide minerals, in particular gold associated with iron sulphides such as pyrite. An alternative two-stage reagent approach is presented that is applicable to certain types of gold ores. This approach involves using very small dosages of uncharged water insoluble collectors at natural ore pH followed by a modified bulk flotation reagent approach for the second stage. The reasons for utilising this approach, when applicable, are discussed and illustrated with examples.

Jan 1, 1997

The techniques used in evaluating gold placers and in recovering gold therefrom are briefly reviewed and critically assessed, relative to the estimated and actual recoveries from many operations. The discrepancies between these quantities can be significant and sometimes disturbing. The coefficient of variation for the annual percentage recoveries, relative to the estimates, is in excess of 10 and commonly above 20 . The difficult- ies in evaluating placers are recogni- sed both in the gathering of meaning- ful sample data and in the derivation of estimates. There are deficiencies, perhaps insurmountable at reasonable cost, in the techniques used to derive an estimate and in the gold saving devices usually employed. There is a subconscious trend to use recovery as a check on the estimate. The industry could have extracted more information during the evaluation and working of deposits in order to fully characterise them and in order to quantify metallurgical efficiency. There is a place for other prospecting techniques, particularly geophysical, in placer evaluation and a need for more appropriate and sophisticated

Jan 1, 1976