Search Documents

By Enever J, Walton R, Wold M

Photoelastic and equivalent material model ling techniques for studying stresses and defor- mations and modes of failure in geological and engineering structures are described. The appli- cation of these techniques to the solution of tunnelling design problems is outlined. Models may contain heterogeneous components to simulate geological and man-made structures and may be two- or three-dimensional. Prototype construc- tion procedures and time dependent behaviour may be modelled. Examples of recent model studies carried out for the design of underground railway tunnels are given. Development of photoelastic and equi- valent material modelling techniques and facili- ties at the CSIRO, Division of Applied Geomech- anics are described, including a biaxial and triaxial frame for testing large scale two and three dimensional equivalent material models and components of full scale prototype structures.

Jan 1, 1976

The 250 metric tonnes of gold and 360 000 metric tonnes of copper recovered from the Mt Morgan Mine in Central Queensland justify its fame. The mine ceased operation before the advent of three-dimensional computer graphical modelling of orebodies became common practice in mine planning. The Mount Morgan Mine records however remain and are the database for this study. The Mount Morgan project takes ore deposit modelling one step further by examining the relationship between grade distribution within the orebody and key geological features, as a tool for exploration and development.The Mount Morgan gold and copper mineralisation is shown to be strongly lognormally distributed. The deposit has been split into three areas, using geological boundaries, each with different geostatistical characteristics. Important features include: the spatial relationship of near-vertical, high grade shoots with a ring dyke thought to be related to the North Dyke; separation of the high grade eastern stopes from the others along the Andesite Dyke; and lack of concentrated mineralisation along the Slide Fault.Recognition of these features is useful to those currently exploring the Mount Morgan district for similar style deposits, by stressing the importance, or lack thereof, of the geological features.

Jan 1, 1993

Full aerodynamic design development of the proposed fans for the enlarged primary ventilation system at Mount Isa Mines Limited was initiated before tender specifications were prepared. Theoretical and analytical design studies were made of many possibilities to determine the optimum proposal. Major considerations were efficiency, simplicity, standardization, and mechanical feasibility. Model testing and experimental work covered blading design, inlet shape, diffuser and tail fairing dimensions, instrumentation requirements, ancl noise studies.Theoretical and predicted performance estimates were prepared for the three 20 ft diameter vertically mounted axial flow fans.

Jan 1, 1967

By Baafi E. Y

Dragline monitoring systems are normally the best tool used to collect data on the machine performance and operational parameters of a dragline operation. This paper discusses results of a time study using data from a dragline monitoring syste

Jan 1, 1998

By Guarascio M, Massacci P

In process simulation, more reliable prediction of industrial results and evaluation of data for design purposes and process optimisation may be attained by the combined use of: the modelling and simulation of ore characteristics, and 2. the modelling and simulation of the process. It is well known that geostatistical methods allow the defining of models of orebodies in which the variables considered are the grades of the valuable components. These models are proper for reserve estimation, geostatistical contouring, design and simulation of the exploitation method, and, in addition, for evaluating the variability of the ROM which is expected to be fed to the processing plant. However, no data are normally incorporated in the orebody model in order to evaluate the ore characteristics relevant for a reliable process simulation. The procedure for process simulation aimed at predicting plant results normally used so far consists in collecting samples from different orebody sites and building up a so-called 'representative sample'. On this sample, the ore characteristics (eg liberation, washability, grindability, etc) and the processing tests are referred to as the 'average behaviour in the orebody', assumed constant. A more reliable methodology consists in collecting samples from different orebody sites, in performing tests to characterise the samples from the point of view of the process (ore patterns), and in using synthetic parameters (process features). The values of the parameters are processed using geostatistical methods in order to develop a model for simulating the feed to the process. The estimation may thus be referred to the amount of recoverable minerals instead of to the existing minerals. Furthermore, the selection of the processes, the sizing of equipment and the design of control devices, as well as the prediction of results, become more accurate and reliable.

Jan 1, 1993

By Stille H

The choice between drill and blast and mechanical boring methods is often not obvious. There are several factors which may have a de- cisive influence on this choice, such as the geometry and length of the tunnel, site con- ditions and borability of the rock. Both the un- confined compression strength and the joint dis- tance have a considerable influence on the net penetration rate. Site conditions, rock quality and water conditions influence the utilization of the tunnel boring machine. The drill and blast method is normally less sensitive to devi- ations from assumed ground conditions.

Jan 1, 1987

A portable surface impedance meter has been tested extensively over a wide variety of geological formations both in Australia and elsewhere. It has proved a useful geophysical too] for relatively shallow mapping (i.e less than 100 metres depth) of faults, intrusions, dykes and conductive ore veins and can be used as a depth probe for overburden and glacial ice. Case studies involving coal seam mapping at Collide (Qld. Australia), galena ore vein location at Zeehan (Tas. Australia) and glacial ice probing on the Brewster Glacier (South Island, New Zealand) are detailed. The first results of a similar unit using a lower frequency with consequential increase in depth of penetration will be presented. The application of VLF measurements to monitor blasting in mines and in the location of earthquake epicentres will also he introduced.

Jan 1, 1987

Carbothermal Reduction and Nitridation of Ilmenite Concentrates and Chlorination of the Reduced Samples

Sep 13, 2010

The interaction of man with the environment has a double character. From one side, mankind can not exist without co- nsuming the natural resources and, from the other side, we actively alter and exert influence upon nature. Analysis reveals that the ecological problem is, to a great extent, a geological one. The paper deals with the application of grouting techniques to construct impermeable barriers for the protection of ground water and soils from depletion and industrial wastes pollution. A number of case histories in the field of mine construction is given to illustrate the solution of geotechnical problems in concert with environ- mental protection measures.

Jan 1, 1988

By Chappel R. A, Fishburn B. R

The Eastern Distributor Tunnels - the first major road tunnel project in Australia - are the preferred solution to traffic congestion problems, when compared with alternatives, in this inner urban environment. This is because of the reduced impact on residential housing, the improvement of the existing environment, less restrictions on future developments, and a reduction in noise and pollution. Developments leading to a tunnelled solution, traffic needs and reasons for route location are discussed. Criteria for design of tunnel alignments and geometry are described, including the restraints imposed by surface connections on profiles and grades resulting in low rock cover at tunnel portals. The main geotechnical restraints are a major weathered dyke at the shallow large span underground fork and the weathered Ashfield Shale capping the Hawkesbury Sandstone at a portal. Rock cuttability and excavation methods are discussed. Roadheader machines are the most suitable for the varying shallow arched cross sections required and the tunnel lengths involved but the use of blasting in special situations cannot be ruled out. Initial support for the major tunnel lengths will be provided by rock reinforcement in conjunction with shotcrete. Steel ribs are proposed in areas of low cover and weak ground. Final support will comprise an insitu concrete lining. Construction concepts and special tunnelling methods required at the shallow underground forks and tunnels are described.

Jan 1, 1987

The paper reviews some characteristic features of feasibility studies and discusses the need for a wide scope at the pre-feasibility stage. The performance of recent Australian gold mines against the predictions contained in their respective feasibility studies is examined, resulting in a recommendation that feasibility studies need to be improved The advantages to be gained from having a feasibility study reviewed by an independent authority are discussed, and some of the reasons for using consultants are listed. Two examples of successful optimisations in the early stages of pre-development studies are described briefly and the benefits achieved are presented. The paper concludes that feasibility studies need improvement to enhance the confidence of investors in the mining industry.

Jan 1, 1991

In North-West Nelson the Riwaka Complex, a linear basic intrusive complex, is exposed for approximately 45 kilometres. Some 500 kilometres south, across the Alpine Fault, a linear zone of similar but less well known basic intrusives that may be correlatives of the Riwaka Complex is exposed discontinuously for about 80 kilometres. The Complex was emplaced at several centers along a major tensional fracture zone that developed in upper Carboniferous to Lower Permian time. This fracture zone probably formed in response to the development of a west dipping subduction zone that gave rise to the Permian volcanic arcs in east Nelson and western Southland. The Riwaka Complex contains three rock suites. The Fractionation Suite, characterized by cyclic mineral layering and small scale cumulus banding is the largest and is divided into the Ultramafic, Hornblende and Plagioclase Series, each of which is subdivided into several units. The Cumulus Gabbros represent a restricted but important suite of unusual composition, while the third suite is the late phase Diorite Suite.

Jan 1, 1980

Valuers of mineral properties should be aware that accountants are a major user of their opinions of value. Reliance by accountants can range from obtaining comfort that book values in balance sheets are not overstated to establishing values by which to assess the fairness of a takeover offer. Accountants using mineral property valuations clearly can't be expected to have the same level of expertise as the valuer and ""second guess"" the valuation. But they do have an obligation, under the ASC guidelines and their own professional standards, to'check the logic and reasonableness of the valuation before being able to rely on it. This means reviewing the valuation report for general sensibility, discussing the methodologies and assumptions with the valuer and being satisfied as to his competence and independence. This paper outlines how accountants use mineral property valuations, the level of scrutiny applied to such valuations and the problems commonly encountered in practice by accountants seeking to rely on them. The paper also explains how values of-mineral properties are established in company balance sheets and why these often differ, quite validly, from fair market values.

Jan 1, 1994

The coal under the ridgeline is the most valuable part of the known reserve at Solid EnergyÆs Stockton Opencast Mine. Some ridgeline mining had been attempted in the past with mixed results. Solid Energy recognised that significant project planning was required in order to overcome the formidable technical issues associated with mining the area. It also recognised that the local community also had concerns about the potential impacts of this work including the visual impact of changing the topography of the ridgeline and the nearness of the Department of Conservation estate.   This paper outlines some of the risks and challenges that were faced and the management approaches that were adopted to address them.

Jan 1, 2007

Railway cuttings require the highest care in design and construction, as the pro- bability of failure concept does not allow any risks to be taken with hundreds of lives being dependent on continued stability. The usual geological influences on stability such as bedding dip and faulting are often discus- sed, but other major problems may come from the presence of sheet joints, cross joints differential weathering and seasonal or daily changes of ground water level. The design of rail cuttings has taken little note of the problems imposed by cons- truction methods, and low cost quarrying methods may seriously weaken a designed shape. The presence of berms and drainage ditches is often difficult to achieve as blasting imposes cumulative stresses and jointing on rocks. Contractors face difficulties in bidding extensive rock cuttings as variations in rock properties are often concealed and overshoot- ing the toe of a batter can easily occur. Modern blasting methods offer some solutions, but the best guide to safe successful cuttings is extensive investigation and the continued involvement of engineering geology at the stages of feasibility, design, construction and maintenance. Two case histories show the influence of folding, faulting and construction methods in the case of slope failure and slope stability.

Jan 1, 1979

By Enga B. E

Following considerable laboratory studies concerning diesel particulate control systems for underground use, a Canadian program was initiated to implement practical, real-life systems. This program covers the application in seven mines throughout Canada, of a particulate control system, to 14 engine models from four engine manufacturers in 18 different vehicle types, for a total of 23 vehicles. Partially funded by the Canadian National Research Council (NRC), this program required detailed analysis of operating cycles, maintenance variabilities and installation problems. This paper summarizes the work carried out to date to define real-world targets and the success achieved so far in attaining practical underground particulate control.

Jan 1, 1988

By Marshall GA

Structural fatigue damage of haul truck frames is a costly problem associated with the operation of large mine haul trucks. A monitoring programme is described which has been instigated to measure stresses in the frames of haul trucks under actual mine operating conditions. The instrumentation used and methodology employed in the computer analysis of the results is briefly described. The results of the monitoring programmes are reviewed, and the effects of various factors affecting structural fatigue damage of three common types of rear dump truck are considered. Factors discussed include the effects of haul route features (for example shovel, dump and crusher areas); the effect of operations such as turning, braking, loading and dumping; the influence of payload; the effects of malfunctions in suspensions; and the influence of haul route surface quality. It is shown that with respect to payload, while structural fatigue damage is increased with payload, the structural damage per unit of payload does not change significantly for moderate increases in payload above the nominal value. Finally, on the basis of these results, recommendations are made for haul route design and operational practices which will increase the structural fatigue life of haul truck frames.

Jan 1, 1986

I would like to start by thanking The AusIMM and CSIRO for organising this excellent conference and inviting me to give a keynote address. Today I will focus on some broad observations of our industry, and leave the technical discussion to my colleagues who are presenting specific papers covering a wide range of topics. In preparation for this paper, I did a little research into the early history of the Pilbara iron ore industry. I was fascinated to read a quote attributed to Harry P Woodward, the Government Geologist in the late 19th century, before Federation. Mr Woodward described the Pilbara as an iron ore country and observed that æthere is enough to supply the whole world should the present sources be worked outÆ. Mr WoodwardÆs prediction could be viewed as wishful thinking and certainly at Hamersley Iron I would gladly envisage the Pilbara supplying the worldÆs entire iron ore needs! In reality, Western Australia accounted for 162 million tonnes or 36 per cent of seaborne trade in 2001. An impressive effort, but not quite the total world supply as Mr Woodward imagined. But we shouldnÆt dismiss these historical musings out of hand û perhaps we could see it as a challenge for the industry to æwork outÆ the present sources. We all know there is abundant iron ore in the Pilbara, and I expect it is only a matter of time until our collective technical expertise and sheer hard work will enable us to utilise its greater range of ore types. Opening up new markets will be a key pathway to creating additional value from the Pilbara ores. Today I will examine the state of play of our industry and the major influences that shape our business at present, before considering what the future might hold for us. I canÆt guarantee the accuracy of my crystal ball, but the stability and long-term nature of our industry does enable some reasonable hypotheses on where we are heading. I will also spend some time examining the way in which the iron ore producers are working to maximise the value of their resource base and obtain more from their existing capital assets.

Jan 1, 2002

By Evans RH, Todd G

Statistical thinking and statistical process ppq;ro4 are essential adjuncts of total quality management aqd too continuous improvement of operating efficiency arid, p*Nc; a4 W,

Jan 1, 1991

Following unprecedented high market prices for tin and gold in 1980, significant advances in both mining technology and geological knowledge took place in northeast Queensland. These led to a rapid growth in mining activity. Production of these traditional metals reached levels comparable to those of the heyday of mining activity at the turn of the century.Although tin and tungsten prices have since collapsed, the geological knowledge gained and significant discoveries made during the boom, have created a potential for mine development when prices rise again. For other discoveries which are not workable because of treatment problems, future technological advances are required to raise their potential.

Jan 1, 1990