Search Documents

In eastern China, most of the copper skarn deposits occur in folded troughs which are controlled by the EW-trending faulted fold systems (the Pal-Asian geotectonic domain), and the NNE-trending rift or fault zones (the Marginal-Pacific geotectonic domain), particularly the later. From the north to the south, there are four troughs hosting the main copper skarn deposits in eastern China: the Yanliao Trough, the Yangzi River Trough, The Qiantang-Yuanshui Trough and the Zichen Trough. There are more than 30 copper skarn deposits in eastern China, and ore reserves of each deposit are between 30 to 100 Mt with average grades over 1 % Cu.

Jan 1, 1995

By Reichman J, Chapman G

The features of seam gas drainage from the point of view of mathematical modelling are outlined and discussed: 1. The use of conventional single phase gas reservoir simulator for very simplified modelling. 2 Alteration of a conventional petroleum reservoir simulator into a specialised simulator for seam gas drainage. 3. Application. of a conventional petroleum reservoir simulator for modelling of seam gas drainage by the way of pseudo-functions and sacrifying one dimension.

Jan 1, 1982

At Yucca Mountain, USA, a tunnel is being built according to nuclear quality standards. It has proved possible to meet very high quality demands while at the same time achieving high advance rates. To be able to do this, routines on how to record and store quality related information have been established. This has meant that a new philosophy has entered the tunnelling industry. Especially for nuclear waste projects, of which Yucca Mountain is one of the first ones to be built, the experiences made and the quality assurance program established will be of great importance for future projects. The paper gives examples of what the Nuclear Quality Assurance system has meant in practice for the tunnelling at Yucca Mountain. And, it also explains why a non-grouted bolt, Super Swellex-, was chosen for long-term reinforcement in the tunnels which might host nuclear waste for thousands of years.

Jan 1, 1999

A new approach to resource estimation at the exploration stage is emerging, based on the application of simple software techniques. The techniques combine the power of interactive graphics with proven database, analysis and estimation tools. With effective use of these tools the geologist now has maximum chance of deriving a reliable structural and grade model from the limited exploration data. Unlike cutoff-based polygonal methods, the resultant geological model can immediately be used to evaluate any economic scenario.These modelling techniques are embodied in MINEX-3D, an Australian software system. With the emergence of the 386-based PC and high resolution (VGA or better) graphics, MINEX-3D makes the power of this new 'desktop geological modelling' accessible to most exploration geologists.

Jan 1, 1990

By Collins D. N

The Olympic Dam Copper Smelter Acid Plant is a hybrid plant capable of producing sulphuric acid from either sulphur burning, metallurgical gases or a combination of both. Commissioning of the Acid Plant on sulphur burning commenced in early April 1988 and commissioning on combined sulphur burning and metallurgical gas commenced in August 1988. During commissioning on sulphur burning a number of acid spills occurred due to balancing of tower flows and control of acid dilution. A number of other significant problems were encountered including failure of boiler gaskets, failure of strong acid pumps seals, the fracture of the teflon dilution water injector and the subsequent failing of the acid circulation pump, tank steel failures and various instrumentation problems. The Commissioning of the Acid Plant on metallurgical gases commenced in August and with the exception of the production of oleum in the boiler economizer was relatively trouble free. Oxygen Plant commissioning commenced in May 1988 and was without significant incident. An outline of the basic equipment for the Acid Plant and Oxygen Plant is presented together with aspects associated with the commisisoning of both plants.

Jan 1, 1989

By Ketelaar P. B, Nichols S, Power W. L, Utley D. C

The impact computers are having in geoscience is distinctly mixed. In the petroleum industry where much of the data are based on geophysics, computers have become an integral part of exploration and reservoir evaluation and simulation. In the minerals industry, the trend to computerisation is more advanced in some disciplines than others. Geophysical and remote sensing data are routinely processed and imaged using state of the art computer techniques. Mine surveying, planning, design and resource and ore reserve estimation are now all predominantly reliant on computers. However senior management of many companies, particularly in the mineral exploration industry, are still reticent to fully embrace the technology. 3D computer modelling of geology and orebody delineation is still largely in its infancy. Two current and significant drawbacks to the routine use of computer modelling of geology in both mining and exploration are the tedious and time consuming modelling process and the lack of seamless interaction between 3D computer-aided drafting (CAD) software and geographical information systems (GIS) which are largely 2D in their data treatment. There is an urgent need for a 3D spatial information system (eg 3D GIS) with intelligent and rapid modelling functionality. One of the keys to the successful building of 3D geological computer models begins with data base structure and design to ensure that there is no loss of data fidelity through data capture, storage, manipulation and modelling. Once a model is constructed, the latest generations of visualisation software provide sophisticated environments over a range of hardware platforms for visualisation in both mono and stereo viewing. This is demonstrated by the geological models which are presented in the digital interactive version of this talk whose URL on the World Wide Web is: http://www.ned.dem.csiro.au/FRACTAL/pubs/talk97AUSIMM/

Jan 1, 1997

By Denisov GA

Conventional processes for disintegration of ores are characterised by low selectivity and cause damage to the components of their structure. It affects their liberation and recovery which are connected also with the inevitable formation of extreme fines. In the world practice recently came into view 4 trend to grinding of materials within a thick layer (in a bed layer), which provides a substantial selectivity of liberation, for example, of kimberlite. The degree of diamond preservation in the final product is highly increased. However, this method causes a considerable overgrinding of material. A new method of intralayer vibro-impulse breaking of materials providing an easily adjusted force acting at the layer and timely removal of product size grains from the grinding chamber has been developed in Russia.

Jan 1, 1993

By P D. Fraser

This paper examines the new water-hydraulic (hydro powered) drill rigs that have been developed and proven in the last decade primarily in tabular, shallow-dipping, narrow-reef, hard-rock South African mines. These include - drill rigs for flat end tunnel development, narrow inclined raises and winzes, large inclines and declines and long hole based developments such as orepasses and vent raises. The hydropower technology rigs offer advantages both in safety and performance over traditional compressed air powered, hand-held development are generally more cost effective than imported oil electro-hydraulic drill rigs. Furthermore, hydro powered rigs are inherently energy efficient. The benefits of hydropower are discussed and a æcomprehensive development modelÆ is presented which demonstrates that orebodies can be accessed in significantly shorter times. æLocalisedÆ half level hydropower systems are introduced and a range of ancillary equipment available is listed.CITATION:Fraser, P D, 2012. The use of high-pressure, water-hydraulic (hydropower) technology in South African narrow-reef, hard-rock mines, in Proceedings Narrow Vein Mining 2012 , pp 229-236 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

The earliest suggestions that some metallic ore deposits might have resulted from seafloor volcanic exhalation seem to have been those of Elie de Beaumont in 1847 and Henry de la Beche in 1851. In 1885 Tinoco, and Bouglise and Cumenge, independently investigating-.the manto copper deposits of the Boleo district of Baja California, proposed that these had formed on the seafloor by precipitation from "hydrothermal submarine emanations". Some twenty years later the Japanese geologists Kukuchi and Tsujimoto (1904) put forward the idea that the Kuroko ore- bodies were seafloor volcanic sinter deposits and in 1919 this was re-affirmed by Ohashi. In 1909 the English geologists Thomas and MacAllister postulated a similar origin for some of the gold deposits of Mount Morgan in Queensland. Between the wars the great European economic geologists Niggli and Schneiderhohn both clearly recognized a class of seafloor hydrothermal deposits. The idea rose again immediately after the Second World War in a very clear statement by Hegeman in 1948, which was followed by contributions by Ehrenberg and Kraume and their co-workers on the submarine volcanic origin of the Meggen and Rammelsberg orebodies in 1954 and 1955 respectively. In 1955 the present writer, quite unaware of early or contemporary work on volcanic exhalative ore deposits, proposed a volcanic sedimentary/diagenetic origin for the stratiform base metal ores of SE Australia. In doing so the writer emphasized the probable importance of island arc volcanism, suggested that some "metallogenetic regions" of ancient terrains were in fact old island arc systems, that the composition of the ores might be related to the composition of the associated volcanic rocks and that such ores would be tied to volcanic stratigraphy. Ideas on relations between volcanism and stratiform ore genesis have thus been evolving over.a period of some 140 years and, beginning with the observations on Baja California in 1882, work round the rim of the Pacific has made an important contribution over a period of more than 100 years.

Jan 1, 1987

It is indeed an honour to address the perth branch of the australian institute of mining and metallurgy and to have the opportunity to talk to you about the future role of upgraded ilmenite on t102 feedstock supply and demand. There have been many papers written on upgraded ilmenite supply and demand and now I would like to share with you QIT's view of the situation first, a word about demand, although I will be talking principally on the supply issue. The principal use of t102 is in the manufacture of pigments which, in turn, are used in paints, plastics, and the paper industry together with a few miscellaneous uses, while a further b% or so of t102 minerals are consumed for the manufacture of titanium metal and for the manufacture of welding electrodes. the total demand for contained t102 is of the order-of 3 million tons per annum, and the general consensus in the industry is that growth rates should be of the order of 2% annually- it is against this backdrop that suppliers must compete with one another and produce least cost materials for the pigment industry. At the moment, supplies are relatively tight, but the generally slow growth in demand coupled with the abundance of titanium bearing minerals should ensure that long term the reverse is generally true. Now, let us examine the supply situation. Titanium is the 9th most abundant element in the earth's crust, so the problem from the producers` point of view is not one of scarcity of titanium minerals, but of how to extract most economically t102 feedstocks from a wide variety of choices- up to the present, all titanium feedstocks are being derived from either rutile or ilmenite rutile, at about 95% t102 content, is indeed a premier raw material which does suffer from potential scarcity and rutile supplies will likely be a diminishing factor in future decades- whereas ilmenite, a combination of iron and titanium oxides found in varying ratios, may be found in huge quantities all over the world.

Jan 1, 1986

Over the last 20 years the mining industry has played a key role in the further development of many Central Queensland and New South Wales communities. The number of people who are employed by the coal mining industry, the number of transient residents, shift work and the town facilities have all contributed to how the community views the coal mining industry. As the coal mining boom continues and the mining communities continue to grow more emphasis is needed to address the community concerns, specifically the socio-economic and environmental impacts that the coal mining companies may have on these communities. Central Queensland coal mining operations are situated in the Bowen Basin. Many of the towns in the region have been developed specifically for the coal mining industry with 13 - 50 per cent (Australian Bureau of Statistics, 2006) of people living in the communities being directly employed by the mines. The introduction of shift work, differing rosters and the mining boom have resulted in considerable changes to these communities with more transient contractors and permanent employees taking up residence outside of these communities. This change, however, has not been as noticeable in the Hunter Valley region. The Hunter Valley, situated in the Sydney Basin has two main mining towns, Singleton and Muswellbrook. Of the 37 173 (Australian Bureau of Statistics, 2006) people that reside in the communities 13.8 to 16.5 per cent (Australian Bureau of Statistics, 2006) are employed directly by the mines. The Hunter Valley is a large tourist destination due to its many vineyards; this results in a diverse community where mining is not the sole means of employment. Similar to Central Queensland the mining boom has brought more people to the Hunter Valley region, although greater percentages have taken up residence in the communities. The views vary between the two regions on the coal mining industry, specifically on the socio-economic and environmental impacts that the industry may have on the surrounding communities.

Jan 1, 2008

By Hanley J

Coal winning in the Latrobe Valley exceeds 45 mtpa uses a small number of Bucket Wheel Excavators and high speed conveyor systems. While this equipment offers many advantages in the production cycle, incorrect use can lead to low productivity and risks to the safety of the operators and equipment. The mining equipment is of high capital value and easily damaged when used outside the correct operating range. In the extreme case, this can result in total machine collapse, having major implications for personnel safety as well as production and costs. With an active productivity improvement program in the Latrobe Valley in the last two years resulting in a 50 per cent reduction of personnel, many experienced operators have retired. Mine management are facing the urgent need to rapidly train new operators to maintain high productivity levels and reduce the risk of accidents to personnel and high capital cost plant. With the assistance of the Central Gippsland College of TAFE a Certificate Level course has been developed for open cut operators. The course covers all essential training needs for the Latrobe Valley mines. The training is developed from National Competency Standards, allowing transfer of skills, and is flexible to suit other enterprises. It has been written for self-paced learning with the total job understanding, and to have competency-based learning outcomes, training tasks and assessments built-in to modules. With the introduction of this new training program, management is convinced that the element of risk within the mine will be significantly reduced. For these reasons it is an ideal training model for other enterprises.

Jan 1, 1994

During 1995 a catastrophic accident took place at the No 2 Vaal Reefs shaft in South Africa, when a locomotive fell onto a cage, causing the death of 104 people. The subsequent Commission of Enquiry found that the safety detaching hook had opened when hit by parts of the falling locomotive, detaching the cage from the rope and allowing the cage to drop 400 m down the shaft. It was believed that had the hook not detached, the rope would have been sufficiently elastic not to have failed, implying that many fatalities may have been avoided. In addition, the risk of accidental opening of hooks due to impact with smaller falling objects in shafts became a concern. This paper deals with a comprehensive statistical investigation that was performed to quantify this risk, establish acceptable levels of such risks and to derive criteria for the resistance of detachment hooks against accidental opening caused by impacts. The investigation involved a survey, dynamic finite element analyses and Monte Carlo simulations.

Jan 1, 2005

Felspar occurs in association with quartz in the Broken Hill lode pegmatites and is brilliant green, greenish white, and white in colour. The pegmatites occur mainly in the walls in sporadic patches, parallel to the general dip of the ore deposit. The occurrences are of no economic value.Deposits of marketable felspar occur in pegmatite in a number of localities around Broken Hill, New South Wales.The majority of these are in the form of an irregular outcrop, usually of tapering length and depth. The maximum depth of any deposit yet worked in the district is about 40 ft. The felspar is occasionally contaminated by "blows" of quartz, mica and beryl, but the two latter are profitably marketable when separated.Felspars vary in colour from pink, through grey to snow white, and the colour is not indicative of the mineral content. The largest deposit at present being worked is the Egebeck quarry, about 14 miles south of Cockburn. It is a prominent outcrop, roughly circular and about 150 ft. in diameter, covered by one to three feet of overburden.The felspar is mainly massive, but contains some cleavage planes at approximately 90°. Intrusions of quartz and mica occur in patches, but the deposit appears likely to improve in size, regularity and quality below the present working floor.COMMERCIAL USES.Commercial felspars are mainly used in the ceramic industry, for which a high-grade potash felspar is required.The dental industry requires limited amounts of soda felspar with a very low Fe20s content. The poorer grades...

Jan 1, 1946

By B Arthur, K Sexsmith, D Hockley, S D

At the proposed Crandon Project, mill tailings would be depyritised for upland disposal. The resulting pyrite concentrate would be disposed of in the underground workings as a cement-amended paste backfill. In the long term, the underground workings would be flooded and the potential for the paste backfill to generate acid would be limited. However, while the mine is operational, there is potential for oxygen ingress to the backfill that may lead to sulfide mineral oxidation and acid generation. A series of humidity cell tests were completed to assess the potential for groundwater contamination. To assess effects of surface area on oxidation, the humidity cell tests were conducted on moulded cubes of paste backfill. The tests were terminated at different intervals, and the cubes were dissected and examined mineralogically. Various leach extraction procedures were also used to assess the progress of oxidation and secondary mineralisation within the paste backfill. The test results showed that: the cement amendment significantly contributes to acid neutralisation and results in a lag in excess of one year before the onset of acidic conditions (in comparison to less than three weeks for the pyrite concentrate); the depth of oxidation in the paste backfill is restricted to about 1 mm after 107 weeks of testing; and secondary minerals form a distinct ærindÆ at the surface of the paste backfill. The results indicate that acid generation in the backfilled stopes would be minimal. The importance of including the surface area effect in the testing (ie using moulded cubes) is clearly demonstrated.

Jan 1, 2003

Scale build-up in titanium palladium alloy spent electrolyte heat exchangers in the residue treatment plant commissioned at Risdon, Tasmania in 1971 was shown to be a mixture of manganese dioxide and anhydrite (CaSO4). The manganese dioxide was deposited as a result of thermal decomposition of permanganate ions present in the spent electrolyte. It was shown that deposition of manganese dioxide and associated anhydrite scale could be prevented by prior reduction of permanganate ions to the manganous (Mn++) state by the addition of ferrous ions. In the plant this was conveniently accomplished by injecting into the inlet line to the heat exchangers sufficient zinc plant solution containing ferrous sulfate to decolourise the spent electrolyte. This action prevented deposition of such scale for another 21 years, until the heaters were finally decommissioned in March 1992. Measurements indicated that addition of the reducing solution lowered the anodic potential of the titanium alloy by 200 - 300 mV (depending on the solution resistance), but that it was still +300 to 400 mV with respect to a standard calomel electrode. It was shown that, if necessary, a small impressed current could be applied to provide anodic protection. Before scale deposition was overcome by the addition of ferrous sulfate solution, badly scaled heat exchangers were cleaned by recirculating a solution of hydrogen peroxide in spent electrolyte or dilute aqueous sulfuric acid, after laboratory testing of a variety of possible solvents for the scale. Corrosion tests indicated that attack on the titanium alloy by the acidic peroxide cleaning solution was insignificant.

Jan 1, 2005

The basic model for the evaluation of any coal-bearing property is the cash flow projection, the major components of which are operating costs, capital charges, taxation and revenue. A range of cash flow projections can be produced by varying the assumptions which underlie the operating costs, by assuming various forms of capital funding, by making assumptions as to future taxation and by speculating upon the present and future market value of the product. As for any model, the informational inputs and assumptions are vital because, no matter how sophisticated the processing, the informational inputs and assumptions cannot be improved by it. That is to say, the validity of the output (the total evaluation itself) cannot be of greater certainty or significance than that of the inputs. The total evaluation can of course be expressed in a number of ways such as the Discounted Cash Flow (D.C.F.) Rate of Return, the Net Present Value or, the Payback Period. The foregoing statement may seem trite. However, it is necessary to be clear about it so as to avoid unnecessary complication and a preoccupation with techniques as opposed to the informational inputs and assumptions. So far as techniques are concerned, much has been written and said about them during the last decade. Most of us have heard, if not always understood, something about probabilistic models, Monte Carlo simulation, sensitivity and risk analysis to say nothing of inflationary costing and the relative merits of developing cash flows in terms of current or constant money. Those techniques have their value, particularly if they can serve to illuminate conclusions which could not be reached on a simple and even perhaps on an intuitive basis. I am, however, reminded of one major coal mining project in which 20 or more major variables were identified, many cash flow projections were run on the computer and a detailed sensitivity analysis was carried out. The major conclusion reached was that the D.C.F. Rate of Return was predominantly sensitive to variations in selling price and operating cost. Of course, the funding and fiscal elements of a cash flow projection have to be dealt with as rigorously as possible. However, in the development of any coal property, capital requirements and taxation are, in part at any rate, dependent upon the assumed operational parameters. If the latter are misjudged, the whole evaluation process is deeply affected. The same is true of revenue, in the sense that, the positive cash flow is a function of output as well as selling price and again, misjudgements about achievable and maintainable levels of production also deeply affect the final evaluation. I shall try to underline the fundamental influence of the technological factors upon lead times, capital costs, operating costs, taxation, funding and the achievable and maintainable levels of production. In turn, these affect the whole question of coal property evaluation and indeed, the likely success or failure of any coal mining venture. I make no apology therefore that this paper does not set out to discuss the more esoteric aspects of the evaluation process but rather, directs attention towards some of the informational inputs and assumptions which merit clarification and discussion.

Jan 1, 1975

It is recognised by the current JORC (1999) code that resource classification involves the interaction of numerous qualitative and quantitative criteria such as data quality, geological continuity and grade continuity. No prescribed criteria and rules will work for all situations or even between different ore types within the same deposit. Also these criteria and rules are sometimes applied without a clear understanding of their appropriateness, accuracy or correct implementation. For these reasons case studies are useful to evaluate and compare criteria commonly used to assist in resource classification. In this paper blasthole data from a selected area of Joffre Member hosted ore of the Brockman Iron Formation at the Mt Whaleback orebody are used as the basis of a case study for the above-mentioned purposes. Iron grade, in per cent, is interpolated from a blasthole dataset into a block model using ordinary kriging. Samples are then removed from this blasthole dataset to produce a random sample grid, a semi-random sample grid and a regular sample grid. Using nearest neighbour, inverse distance squared, ordinary kriging and sequential gaussian simulation, block iron grades are estimated using these three blasthole data subsets as inputs. This provides four groups of estimates with the ordinary kriging estimate based on the complete blasthole dataset being considered to represent the true estimate of iron grades. Also generated during this process are estimates of the error for each block. These error estimates range from the simple, such as drill spacing, through to more advanced methodologies such as kriging efficiency and simulation. These estimates of grade and grade estimation error are then compared to the true estimate using graphs and statistics. In order of increasing accuracy the block grade estimation and simulation methods were nearest neighbour, inverse distance weighting, ordinary kriging and finally conditional simulation. The simulation in some instances doubled the accuracy of individual block grade estimates when compared to nearest neighbour and inverse distance weighting estimates. It was found that many methodologies for estimating the error of individual blocks performed equally well with only methods such as average drill hole spacing and classification by search ellipse pass number performing poorly. An approach on how to convert the abovementioned error estimates of individual blocks into a meaningful JORC classification is also discussed. Although advanced non-linear resource estimates are applicable, most iron ore mines are still using relatively straightforward methods. The use of blasthole data and some simple linear interpolation methods and simple linear based error estimates makes this study repeatable for most iron ore sites and their resource geologists. This style of investigation is recommended as a useful approach for the Competent Person to apply to their deposit and thus better select, implement and understand the criteria used for resource classification and provide more consistency and confidence in the resource classification process.

Jan 1, 2002

By Tukkimies M

During the late-1980s crawler-mounted crusher units established their position in the aggregates industry. Between 1986 and 1994 about 700 units were delivered to customers all over the world for surface operations, mainly in Scandinavia and central Europe. The crawler-mounted units are popular among smaller crushing operators because they are versatile and easy to move between sites. In large quarries the greatest benefit is obtained by combining a primary crawler-mounted crusher unit with mobile belt conveyors which eliminates the need for costly haulage by dump truck. Savings of up to 40 per cent in production costs prior to secondary crushing have been achieved. Today the environmental aspect in quarrying is assuming ever greater importance. Besides being costly the dump trucks are also the major source of dust and exhaust fumes within a quarry. A complete face crushing system consisting of a crawler-mounted crusher unit and mobile belt conveyors can be electrically driven and can be equipped with dust encapsulation and dust collectors. A mobile crushing unit is not a new idea. From the mid-1950s onwards the mobile and self-propelled units have been built equipped with crawlers, tyres or walking mechanisms, with weights usually of 500-1000 t. Due to their massive size these unit are not mobile in the same way as the today's mobile units. It is not feasible to move them more than a few times a year unlike today's fully mobile units which are often relocated once an hour. This means that the massive units can not continuously follow the production face and their loading always requires a certain amount of haulage. Today the mining industry is facing new challenges. With low mineral prices and high labour costs, increasing productivity is essential for survival. New standards are also being set for the labour safety and the environment. Large research programs have been launched to meet these challenges. However, technology which can partly solve these problems already exist and is only waiting to be introduced into underground applications as well - the mobile crushing unit followed by belt conveying. As in surface operations the elimination of truck haulage also brings considerable savings in operating costs in underground mines and reduces the amount of dust and exhaust gases generated. An additional benefit especially in underground applications is improved safety. In an underground mine most accidents are caused by moving vehicles.

Jan 1, 1995

Research programs have established the correlation between the basic mill operating parameters such as: size of crushing products, number of mill rotation, ore flow and quantity of ore in the mill, diameter of grinding media, and specific consumption of grinding media. Also, the mill efficiency has been determined in dependence of adsorption. Mathematical dependences and equations are presented in this paper.

Jan 1, 1993