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The crushing and concentration of ores, as Herbert Hoover commented in a footnote in De Re Metallica, stretches back at least 6000 years. During those years there have been continuing changes and improvements in mineral processing technology. It has expanded greatly in its ability to handle different types of minerals, and lower grade and more complex ores. Australia will be dependent on the mineral industry for the fore- seeable future and there will be continuing demands on the mill opera- tors to improve the technology with regard to efficiency, flexibility and costs. These demands will be met successfully in the future as they have been in the past. This Mill Operators' Conference is an important forum for assessing our present position and planning for the future.

Jan 1, 1988

By Lawrence L. J

The Australian Broken Hill Consols Mine, situated some 600 yd east of the main Broken Hill line of lode, is noted for its rich ores of silver. In contrast to the vast conformable orebodies of the Broken Hill field, the Consols lode occupies a narrow fissure dipping to the south west at angles increasing from 240 through to vertical and transgressing the strike of the metamorphosed country rock at an oblique angle. This feature, together with the abundance of calcite and siderite and the virtual absence of silicate minerals in the gangue, has led to its classification as an orebody of the Thackeringa type (King, 1953). Recorded production during the period 1890 to 1903 is given as 845,000 oz of silver and 20 tons of lead.The unusually rich silver values of the Consols lode were concentrated at the intersection of the fissure with beds of amphibolite, whereas in the adjacent schists and gneisses the lode became markedly impoverished. From the surface to a depth of some 120 ft extensive surface oxidation had occurred, resulting in the breakdown of siderite and its replacement by limonite and associated manganese oxides.Silver halides, dyscrasite, acanthite and partly oxidised tetrahedrite were the main silver minerals in this zone. With increasing depth the lode material gradually reverted to minerals representative of the hypogene zone.The only previous work specifically on the mineralogy of the Consols lode is that by Smith (1922), one time manager of the mine. His zeal as a mineral collector resulted in much valuable information being available on the distribution of the minerals. More recently, Garretty (1943) noted the...

Jan 1, 1962

THIS SYMPOSIUM ON AUSTRALIAN BEACH SANDS IS MOST TIMELY; WHEN WE ARE APPROACHING PEAK PRODUCTION FROM THESE RESOURCES AND WHEN PRICES ARE GOOD, BUT THE RESOURCES CAN BE SEEN TO BE COMING TO AN END IN THE LIFETIME OF OUR YOUNGER COLLEAGUES - 20 TO 25 YEARS AS WE HEARD FROM ROY TOWNER TODAY. THE SPREAD OF PAPERS HAS BEEN 15 PERCENT EACH ON GEOLOGY AND THE MINERAL RESOURCES, WITH 25 PERCENT ON LAND USE AND ENVIRONMENTAL PROBLEMS. I AM PLEASED TO SEE 20 PERCENT HAS BEEN ON TREATMENT PROCESSES AND 25 PERCENT HAS BEEN CONCERNED WITH DOWNSTREAM USES. I SUSPECT THESE RATIOS ARE DUE IN PART TO THE WAY PAPERS WERE CALLED FOR, BUT THEY ALSO SUMMARISE CLOSELY THE BALANCE OF INTERESTS IN THE INDUSTRY. NOTE AGAIN; 30% CONCERNED WITH SUSTAIN -ING RESOURCES, BUT 25% WATCHING LAND USE AND IMPOSING CONTROLS; 20 % IMPROVING THE PRESENT PROCESSING, AND A HEALTHY 25% WITH AN INTEREST" IN WHAT HAPPENS TO THE MINERAL CONCENTRATES. I SHALL RETURN TO THIS FOURTH POINT AT THE END OF MY REMARKS. THE POSSIBILITY OF ADDITIONAL HEAVY MINERAL SANDS IN NEW AREAS WAS HINTED AT BY M.S. SHEPHERD (EG TERTIARY SHORELINES OF THE MURRAY BASIN). OLD FOSSIL SHORELINES, WELL REMOVED FROM PRESENT SHORES ARE AN IMPORTANT MINERAL SOURCE IN CHINA AND IT WOULD HAVE BEEN INTERESTING TO HEAR FROM THE SEVERAL COMPANIES EXPLORING IN THE MURRAY BASIN. I ALSO NOTICED THAT WHILST OUR MONAZITE

Jan 1, 1986

By B Roach, P M. Ashley, B Hooper

Mineral occurrences of the Hillgrove Au-Sb-W district are hosted in late Palaeozoic polydeformed, hornfelsed metasediments and Permo-Carboniferous granitoids of the NewEngland Orogen. In excess of 204 individual occurrences have been identified to date with the mineralisation developed as strike extensive (>20 km of known veining) and potentially depth extensive steeply dipping fissures. These are contained within an elongate area measuring some 9 km by 6 km in surface dimensions. Recorded gold production of 720 000 ounces along with current resources in the order of 340 000 ounces highlight the significance of this district. Historical antimony production is estimated at in excess of 50 000 metric tonnes. Significant tungsten of over 2000 t in the form of scheelite has also been produced from the field. Mineralisation is developed in veins, vein breccias, sheeted veins, network stockworks and as alteration sulfide haloes to the main structures. The vast majority of fissures are subvertical and vary in widths of up to 20 m in places. Paragenetic studies have previously indicated that the earliest mineralising event was a scheelite-bearing phase of quartz veining. Subsequent phases of arsenopyrite-pyrite-quartz-carbonate veining were accompanied by gold and minor base metal sulfides. Alteration is typically sericite-ankerite-quartz. Overprinting stibnite-quartz veining with gold-electrum, aurostibite and arsenopyrite form an important subsequent phase. Veining can be inferred from historical records to extend for vertical depths of over 1 km.

Jan 1, 2004

By J Bartlett, P Quigley

Historical research has played a significant role in the rebirth of the Bendigo Goldfield. The historical research undertaken by the company has been directed to specific areas such as verifying the total gold production of the field, the gold production from defined blocks on each of the major anticlines, the extent of workings of each mine which exceeded 200 m depth, the size and style of reefs mined in each shaft and also within specific domains of the field. Application of this data has assisted in the determination of possible dimensions of different reef styles and the location of mineralisation within each reef system. Description of grade variation, percentage of quartz and the amount and species of accessory sulphide minerals, as well as early geotechnical observations accompanying stoping methodologies, provides valuable analogues for reef structure being defined in the current program. Historical information on shafts on the two anticlines the company is exploring has allowed the postulation and recognition of repetition of reef development within the same stratigraphy in the hinge zones of the adjacent folds. The similarities of mineralisation styles across the field within both specific lithological units and structural setting has had important implications in respect to exploration drill targeting and the estimation of grade and tonnes.

Jan 1, 2003

The Mungana group of mines, in the Chillagoe district, yielded 334,000 tons of ore giving 31,831 tons of lead, 7,907 tons of copper and 3,228,600 ounces of silver. The Girofla mine produced approximately 220,000 tons of ore, and with the Lady J ane mine supplied most of the ore from this centre. The deposit was discovered in 1888, but active development did not commence from the main shaft until 1898. A subsidiary of the New Chillagoe Railway and Mining Co. Ltd., the Mungana (Chillagoe) Mining Co. Ltd., worked the mine from 1902 until 1914, selling copper, copper-lead, lead ores and fluxes to the smelters at Chillagoe. The smelters stopped operations in 1914 when the richer ores of the Girofla had been worked out and production from the Lady Jane had ceased due to heavyground and fire. The Girofla shaft was 823ft. deep with a cross-cut at 810ft. At the 710ft. level contour drives had delineated the orebody, which had been stoped about 10ft. above the level. Except for flux ores which had been stoped only for favourable smelter tariffs, the orebody was practically exhausted above the 610ft. leveL Under company ownership the mine yielded 139,265 tons of an average grade of 4.QlYr copper, 16.2% lead and 12.5 oz. per ton silver.In 1921 the Queensland Government re-opened the mine and worked it until 1927. The North Lode (Fig. 2) was discovered almost immediately at the 100ft. level and was worked down to the 410ft. leveL The ore from this branch and the completion of the stope at the 710ft. level yielded about 80,000 tons of ore averaging 0.4 copper, 9.8 lead and 7.8 oz. per ton silver during this period.

Jan 1, 1953

By A Taheri, G D. Nguyen, M Karakus, S Akdag

During underground mining operations, rock masses are highly subjected to dynamic disturbance caused by blasting, mechanical drilling and earthquakes resulting in strain burst, slabbing and spalling. The dynamic fracture is a significant manifestation of rock failure in deep underground engineering, and it is of great importance to assess the dynamic fracture behaviour of the rock mass under elevated temperature conditions. The correlation between temperature – and loading rate-dependent dynamic fracture mechanism of strain burst is yet to be established. A good understanding of the dynamic fracture behaviour of brittle rock subjected to high-temperature under dynamic loading is required for the prediction of the damage extent during strain burst, and proper design as well as control of the underground rock structures. In this study, dynamic mode I fracture toughness tests are carried out on cracked chevron notched semicircular (CCNSCB) granite specimens to reveal the dynamic fracture characteristics of the brittle rock. For this purpose, a Split Hopkinson Pressure Bar (SHPB) apparatus is utilised to conduct the dynamic tests with various striker velocities on thermally degraded granite. The dynamic mechanical behaviour of granite after high-temperature treatment is examined and discussed. The dynamic fracture toughness is determined and compared for the specimens exposed to different temperatures at various dynamic impacts. The fracturing processes are recorded by a high-speed camera (HSC), and the crack propagation speeds are estimated by HSC image analysis. In addition, the dynamic fracture process and the coupled effects of temperature and loading rate on the dynamic fracture modes are identified by HSC image analysis. Energy partition characteristics in dynamic fracture of granite are quantitatively investigated.

Nov 29, 2022

THE absence of any locality maps of the district of Morobe has been seriously felt by mining engineers engaged on the goldfields, and as it was evident at the beginning of operations that the administration would be unable to make good this deficiency, ascheme for making rapid traverses was worked out, and in all subsequent travelling the necessary records were kept for the construction of a reliable reconnaissance map of the Bulolo goldfield and its approaches (see Plate 1.). Since all the field work had tobe carried out without encroaching on primary duties, the compilation of sufficient data was a somewhat lengthy business. It was found that in this r;ough country a pedometer was useless, as it was impossible to calibrate it for the variation in length ofpace between climbing semi-precipices and walking over level country. Further, the native tracks "meander" so excessively that the only method of calculating air-line distance is by timing, and a knowledge of what the timing represents, and until a 10kg experience had been gained in the time taken to cover known distances in various types of-country, one could not feel competent to estimate sufficiently accurately. It was found that reliability could be attained only when walking at nearly top pace. Inregard to aeroplane traverses, results were reliable only when the air was fairly still.BEARINGSIn arriving at the bearing between main traverse points, the method used was to keep a "boy" about two chains- behind when marching and sight back on him, standing, at about two-chain intervals. These bearings were averaged into the field book at the end of the day, each line being averaged separately. As the roads became known, it was possible to get a considerable amount...

Jan 1, 1928

By N C. Steenkamp

The Northern Cape Province of South Africa is host to the Kalahari Manganese Field (KMF). The northern portion of the KMF hosts high-grade manganese referred to as Wessels’ type ore and is mined mostly from underground operations. WorleyParsons TWP is currently involved with the development of a ventilation shaft for one of these mines. The main challenge is to develop through the unconsolidated Kalahari material and weathered portion of the Karoo formation. These formations are preserved very erratically over short distances. A lack of understanding of the unique challenges presented for developing shafts in this area has resulted in the failed development of a shaft on an adjacent property and over-expended budgets on others.The renowned red sand of the Kalahari forms the top several tens of metres and overlies a horizon of gravels and calcrete that pose seasonally variable water ingress problems. A very stiff red clay horizon is then intersected. The Red Clay is prone to swellling during excavation and has been the main stumbling block on previous constructions. The standard approach has been to develop non-stop through this layer. The red clay is underlain by another horizon of calcrete, gravel and conglomerate that marks the bottom of the formation. The top of the Dwyka Tillite (Karoo Formation) is usually highly weathered and has a distinctive yellow colour. The weathered tillite is highly susceptible to drying and becomes friable. At reef-intersection, the combination of subhorizontal bedding and joints with the dominant subvertical faulting results in potential wedge failures in the manganese and ironstone units.This paper describes the geotechnical issues identified during the planning of the ventilation shaft and the risks associated with development through the Kalahari and weathered Karoo Formations. A new approach to developing ventilation shafts in overcoming these challenges is recommended.CITATION:Steenkamp, N C, 2014. Challenges of developing a ventilation shaft in Kalahari and Karoo formations, Northern Cape, South Africa, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 81–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

The stratigraphy of the Singleton Coal Measures is reviewed and a revised stratigrapixy which has been ratified by the N.S.W. Standing Committee for Coalfield geology is nominated and defined by a selected type section. Withir the type section the occurrence of repetitive phases are illustrated and described. Coal. Measure units within the Singleton Coal Mean sures, termed the Wollombi and Wittingham Coal Measures respectively, are correlated with the Newcastle and Tomago Coal Measures. In formal nomenclature the Singleton Coal Measures are designated the Singleton Super Group. The major depositional cycles within the Coal Mea- sures are outlined together with those lesser phases within the Coal bearing sequences that influence the mining conditions likely to be encountered. Both tectonic and sedimentary features of the Singleton Coal Measures are considered and the localized post depositional effects on the coal seams and roof strata in- duced by differential, compactions are emphar Sized.

Jan 1, 1972

By Blattner P

The Late Miocene gold-silver bearing epithermal system at Waihi has some close similarities in its paleo-thermal and -geochemical structure with modern, volcanic-hosted geothermal systems such as Ohaaki-Broadlands. At Waihi an extensive braided quartz vein system is enveloped by hydrothermally altered andesites with minor tuff breccias and tuffs. A main stage of vein filling consists of multiple phases of chalcedonic quartz and fine to medium grained quartz, which are accompanied by pyrite, sphalerite, galena, chalcopyrite and acanthite below the base of oxidation. Platy calcite is present locally. Fluid inclusion studies indicate that the main stage quartz was deposited at temperatures of 189¦-273¦C from dilute (T¦ of -0.1 to -1.0¦C) fluids that were locally boiling. Homogenisation temperature Th versus T. data points lie within the field enveloped by dilution and boiling/gas loss paths determined for the Ohaaki geothermal field, and indicates that the parent hydrothermal fluid for the Waihi epithermal system had a similar composition to that at Ohaaki, ie 0.2 wt% equiv NaCI and 3.3 wt% equiv CO2. The hydrothermal alteration mineralogy and the isotopic composition of vein calcite indicate that the hydrothermal fluid contained relatively high concentrations of CO 2' as at Ohaaki. Oxygen isotope analyses of main stage quartz range from 6.1 to 11.6 %o and of vein calcite from 2.29 to 9.4% . Calculated d8Ow.½ values for the hydrothermal fluid that deposited the main stage quartz range from - 2.0 to -5.7%c , with a trend to less negative values with depth. They are similar to those in the deep chloride fluid in active geothermal systems with a substantial fluid throughput. A high fluid throughput at Waihi system is also evident from the extensive high intensity hydrothermal alteration and large volume of quartz deposited in the vein system.

Jan 1, 1995

By P SSrkkS

Mining is commonly seen as a typical basic industry with rough and even dangerous working conditions, heavy environmental load, and a low level of high-technology and automation with much manual work and operations. A mining operation (open pit or underground) is a very complex one consisting of many manual, physical, mechanical and logistical operations with different human interfaces and decisions. For this reason it is a demanding and potential area for all applications of automation and information technology: controlling difficult non-linear, time varying multivariable processes and machines; solving of ergonomic safety and environmental problems; automation of logistical systems; applying robotics, mechatronics, and information handling, etc. In addition to that, big economic sums are involved with these operations. On the other hand, automation technology has developed towards intelligent and adaptive systems including some from the above mentioned fields of automation. Connecting them with modern information and communication technologies makes the idea of an intelligent and unmanned mine more and more feasible in the near future. This requires intensive co-operation and co-ordination between the mining industry and manufacturers of mining machinery. This has been successfully accomplished in the five-year Intelligent Mine research and development program as well as the three years of subsequent implementation of its results in Finland. The basic elements of an Intelligent MineTM concept are:mine-wide information and data acquisition system; high-speed two-directional mine-wide communication network for real-time monitoring and control; computerised information management, mine planning, control and maintenance systems; automated and tele-operated machinery and equipment which are connected to the information system; and links to the public information networks. The degree of automation of an intelligent mine depends on many technical and economical factors. The basic precondition for such an approach is that it will improve the total economy of the mine. This paper will describe the Intelligent Mine Technology Program with the results. Also the implementation which took place during starting of a new underground mine (Outokumpu Chrome Oy Kemi Mine) will be described.

Jan 1, 2000

By Wharton P, Voigt R

In order to do the discharge estimation better, it is valuable to find out appropriate formulas for estimating discharge in various pits, based on accumulating data, summarizing discharge patterns applying optimum seeking method and principle, by seeking redical exponent with help of the method of exhaustion, as well as testing and making statistics, in accordance with the quality standards established by our practical experience.

Jan 1, 1988

By C Kocsis, G Baiden, Y Bissiri

CANMET-MMSL and Penguin Automation Systems Inc have been exploring how process simulation and ventilation modelling software, when combined, can be used to optimise hard-rock/metal mine ventilation systems. In combination, it is anticipated that this methodology will facilitate the exploration of mine design options that affect ventilation requirements and ultimately cost. Such integrated mine design could limit, and possibly reverse, the drivers that under current practices would generally dictate increased ventilation, power consumption, cost and greenhouse gas emissions. It is believed that the mining industry needs such process models to develop better business cases. For example, the implementation of optimised ventilation systems will undoubtedly require significant investment and mines are often reluctant to try such conservational measures unless they can be proven cost-effective. In general, Canadian hard-rock mines know their ventilation systems are providing too much air and consuming power unnecessarily. This is because their systems are designed to provide maximum production flexibility, based upon peak demand, which may be at some future time, and operated continuously at that level regardless of actual need. Simplistic analyses have shown electrical energy savings can range from 30 per cent through to 90 per cent (Hardcastle, Gangal and Leung, 1998). These savings depend upon such factors as the intensity and continuity of the production schedule as opposed to non-productive time. Where these savings occur is also important, if limited to either the primary or auxiliary ventilation systems, they could be negligible in a mineÆs total energy consumption. The problem these mines face is determining what level of ventilation is required in real-time and then the relative benefits. Such parameters as varying electricity costs, heating fuel options, different design criteria and their complex inter-relationship can effect the selection of an optimal system, depending on whether energy, environment or cost is the prime driver. The use of process simulators in underground mining is in its infancy; to date they have been used to show the benefits over the life of a mine under different mining methods, such as a comparison of tele-remote mining from surface against conventional manned operation (Baiden, 2000). This ongoing development advances the use of such simulators into a new and potentially important area, namely modelling the life-cycle ventilation requirements of a mine. This paper shows how such a life-cycle analysis as opposed to peak demand can provide the basis for optimising the design of ventilation systems and their control.

Jan 1, 2005

Over the past seven years, a combination of New Zealand-, Australian- and German-led research voyages using the research vessels Tangaroa, Southern Surveyor, and Sonne respectively, have revolutionised our understanding of the Kermadec-Tonga arc-backarc systems. This convergent margin is the most seismically-active subduction zone system on Earth with convergence rates steadily increasing northwards from the Hikurangi Trench to ~250 mm/year at northern Tonga. In combination with the intra-oceanic setting, factors potentially producing magmatic, tectonic, and hydrothermal variability in this system include an increase in potentially subductable sediment northwards along-strike, intersection of the Louisville Ridge (hot-spot chain) and Osbourn Trough (paleo-spreading centre) with the arc at ~25¦S, and the possibility of Samoan (hot-spot) plume ingression in the northern Lau Basin. The bulk of the magmatism is submarine; whereas only a few emergent (some transient) volcanic islands exist, about 80 submarine volcanic centres of significant size (>1000 m above surrounding sea floor) are present between White Island in the south to north of Tafahi in Tonga. About 35 per cent of these centres are hydrothermally active. Important petrogenetic features of the volcanic rocks along this arc system are the abundance of rhyolite (some quartz-amphibole-bearing), and the outcrop of primitive olivine-clinopyroxene-phyric basalts in satellite cones of the major edifices. Many of the edifices consist of complex caldera systems. Eruptions from and degradation of these edifices were probably tsunamigenic. Many of the hydrothermal systems developed within the edifices are likely destroyed during the sector collapses which are the characteristic edifice degradation mode. There are three backarc spreading systems along this margin: the Havre Trough, Valu Fa-Eastern Lau Spreading Centre, and the nascent Fonualei Rifts. The latter are particularly notable in having captured the entire suprasubduction zone magmatic flux for a distance of about 150 km, shutting down the adjacent volcanic front arc volcanoes.

Jan 1, 2005

By Andrews JRG

Chrysotile asbestos is a valuable resource. Used as a reinforcement in asbestos cement, products are obtained which are cheap, are not attacked by vermin, do not rot or support growth of fungi and are unaffected by water or humid conditions. Such products are of great value in the developing countries where inexpensive and durable building materials and pressure pipe are very important to development, housing and water supplies. Concern over the adverse effects of inhaling asbestos has led to the introduction of increasingly stringent controls world wide on the quantities of airborne asbestos per- missible in the occupational situation. Wet processing has the potential for virtually eliminating the environmental concerns with asbestos dust both in fibre production and in the materials handling section of the manufac- ture of asbestos cement products. In addition, high efficiencies associated with wet process- ing mean that better yields are obtained and that the tailings which are dumped have a lower residual asbestos content. Since early 1977, ICI Australia and Woodsreef Mines have been engaged in a programme of research to develop and evaluate a wet mill- ingprocess to produce, from ore and existing tailings, high grade fibre suitable for use in asbestos cement products. The process has been developed through microscopic studies, labora- tory bench scale experiments, work in a small scale semi-continuous plant and product evalua- tion on experimental size Hatschek asbestos cement machines. A prototype mill with a normal feed rate of 1z tonnes per hour and capable of producing pipe grade asbestos from Woodsreef ore has been constructed and was operational from January, 1982 to July, 1983. A range of asbestos cement products have been made successfully on full scale Hatschek machines using fibre from ore and tailings milled in the prototype mill. Economic evaluations indicate that a wet process mill would be cheaper to build, operate and maintain than an equivalent dry process plant. A commercial plant has been designed 1. Manager New Process Development, Woodsreef Mines Limited, Barraba, Australia. 2. Senior Lecturer, Department of Chemical Engineering, Monash University, Vic, Australia. formerly Senior Research Officer, Research Department, ICI Australia Limited

Jan 1, 1986

Low-grade, porphyry copper type mineralization at the Moonmera prospect is related to the intrusion of a granodiorite porphyry mass into the Upper Permian "Gracemere granodiorite". Significant copper mineraliza- tion appears to be associated with the alteration assemblage quartz-sericite- kaolinite. The ore shell is surrounded by a zone where montmorillonite and kaolinite are in greater abundance and this assemblage is over- lapped, mainly at depth, by potassium feldspar alteration. Secondary biotite is abundant throughout the mineralized zone. Preliminary sulphur isotope results on the sulphide mineralization are compatible with a magmatic origin for the sulphur.

Jan 1, 1974

By Wilson CJN

The central Taupo Volcanic Zone is a region of intense Quaternary silicic volcanism accompanying rapid crustal extension. Modem central TVZ is the most frequently active and productive silicic volcanic system on Earth, erupting rhyolite at c. 0.28 m' s'. The rhyolites show no major compositional changes with time, but the total extent of magma chamber zonation has changed with the advent of rifting and crustal extension at c.0.7 Ma. At least 34 caldera-forming ignimbrite eruptions have formed a complex sequence of relatively short-lived, nested and/or overlapping volcanic centres in central TVZ. Taupo contrasts with other large silicic magmatic systems in the exceptionally high frequency, but small size, of caldera- forming eruptions. This contrast reflects the thin, rifted nature of the TVZ crust, that precludes the development of long- term magmatic cycles at Taupo.Within central TVZ, non-rhyolitic compositions have been erupted apparently irregularly in time and space; in particular there is no evidence for a geographic separation of basalts from andesites. TVZ is a rifted arc, but its segmented nature, high thermal flux and voluminous rhyolitic volcanism make it unique on Earth.

Jan 1, 1995

The mineral sands deposit of Australia pose a number of unique, and quite unusual problems for the explorationist. Most concentrations of heavy minerals have been found in the unconsolidated sediments of the east and west coasts. Mineral sands mines open larger areas per tonne of concentrate than most other mines. This is because of the shallow depth of the sands containing the heavy mineral concentrations. Obtaining tenure can, by mining industry norms, be a massive operation due to the large areas to be examined and, particularly on the east coast, the large number of land holders encountered. A commercial development can still emanate from anything ranging from a small high grade body to a massive low grade deposit, the prices currently being obtained for rutile, zircon, ilmenite and monazite, although still modest when the remarkable properties and applications of these minerals are considered, is nevertheless attractive when compared to the prices being obtained for the base metals with the exception of gold. The current interest in the location and definition of new reserves of heavy minerals reflects this relative price attractiveness. The discovery of heavy mineral concentrates does not necessarily ensure the early establishment of a mine. Because of the cyclical nature of market prices, the average returns likely over the life of the mine permit the employment of only relatively simple, low cost, mining, concentration, and separation processes. If difficult mining conditions are encountered or the removal of small contaminants by complex metallurgical processes are required, then higher market prices must be obtained. Until the market is prepared to pay more for the commodities so produced, the resource will not be economic and lower cost reserves will be mined in preference. The Australian mineral sands industry has seen many closed mines because of past failures to properly assess the data base collected during the exploration and development phases of the failed projects.

Jan 1, 1987

In general the iron ore industry has been slow to adopt the Whittle Pit optimising software in the evaluation of iron ore deposits. The reasons for this are two-fold:the iron ore industry has developed techniques, usually bespoke software residing in the corporate offices of the respective iron ore companies, to establish their final pit limits; and the fact that the Whittle software doesnÆt easily lend itself to estimating a sales product of constant quality without maximising grade (metal content). The Whittle software is based on the work done by Lerch and Grossman (in the early 1970s), which proposed that graph theory be used to establish an optimal surface that maximises the revenue from a deposit. The maximised surface created in the pit optimiser is translated into a proposed optimal final pit shape that can be used by the mine design engineers as a target outline to lay out the final practical pit. By treating a geological and ore resources model that was created for an iron ore deposit as a subset of the recoverable resources estimation (RRE) type of geological models, the evaluation of an iron ore deposit and establishing the final pit is greatly simplified in the Whittle 4-X optimiser. Instead of trying to optimise the iron content of the deposit, the emphasis swings to maximising the extraction of a finished and saleable iron ore product. This is achieved by treating the finished saleable iron ore as an element in the multi-element Whittle optimiser. The quality of the finished sales product is represented, and the material that cannot be used in the blended product is also shown. Proposals for enhancing the functionality in the Whittle 4-X optimiser to make the evaluation of iron (and coal) deposits easier includes the creation of a new reporting function that will allow the user to specify which field(s) can be used as the divisor(s) for the reporting of the element grades in the model.

Jan 1, 2007