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The aim of all modelling is to replicate geological reality as closely as possible using available data. This paper is aimed at one end of the spectrum, where very limited data is combined with intuitive geological ideas to synthesise models for either target definition or for determining minimum viable mining scenarios. Interactive 3D modelling allows a satisfactory hypothetical geometry of surfaces to be assembled, and provides a fast quantitative method for generating targets. As data flows from exploration, an evolving geological model assists with the progressive evaluation of a prospect. Two case histories are described where this approach has been used successfully, the Mosquito Hill Prospect in Queensland and the Longwood Ranges Platinum Prospect in New Zealand. The possibility is also discussed of hypothetically modelling an orebody which has yet to be discovered. The proper description of an orebody is the foundation upon which all mine design and planning is undertaken. The volumetric accuracy of the model is crucial in valuing an orebody. Geologists must form a geometry which matches the conceptual view of the ore occurrence and ensure that they understand how the computer system used calculates volumes. If the underlying assumptions inherent in the method conflict in any way with the conceptual model visualised for the ore occurrence, then that method must not be used.

Jan 1, 1995

In 1965, Peter Flawn author of the famous text-book on Mineral Resources (1966) published a paper in Economic Geology with the delightful title `Who took the `Economic' out of Economic Geology?'. He opened this most interesting article with the following paragraph:If one were called upon to cite an example of a fish out-of-water he could hardly pick a better one than a recent graduate of geology of an America university who is suddenly faced with the responsibility of evaluating or appraising a mineral property. And I venture to say that the 'ftsh' with a doctorate - even in economic geology - is not much better equipped than one holding a lesser degree. The new graduate with a major in economic geology probably knows the significance of the various sulphur isotopes, he surely knows a great deal about the chemistry of the ore forming fluids and he recites with ease the arguments which prove deposits are epigenetic rather than syngenetic. However he is a rare bird indeed if he knows anything about the economics of the mineral industry. The truth is that geologists who are engaged in evaluation work are largely self taught. I ask my more distinguished and experienced colleagues - `Has it always been this way? Who took the `economic' out of economic geology?

Jan 1, 1993

By Haartti J

Generally when equipment is chosen for solving a dewatering problem, the equipment is based on one of following physical methods: gravity (sedimentation, screens), vacuum (vacuum drum and disc filters, belt filters), pressure (filter presses, hyperbaric filters) and centrifugal forces (centrifuges). The choice of method and type of equipment depends, among other things, on the requirements on the maximum water content allowed in the filter cake and on the particle size distribution and the concentration of solids in the material to be dewatered. All the above-mentioned equipment has its benefits and drawbacks. The conventional vacuum filters of drum or disc type are of a simple construction with few parts to be replaced, but these filters produce a filter cake with a fairly high moisture content, and a dryer is required for additional drying. In most cases the use of pressure makes it possible to produce filter cakes with the desired moisture content but the equipment is of complicated construction, leading to high maintenance costs . In addition to this the consumption of compressed air is high. The capillary filtration to be described in this article is a dewatering method which combines the benefits of both the conventional vacuum disc filter and the filter press. The capillary filter produces low cake moistures with a machine of very simple construction similar to that of the vacuum disc filter.

Jan 1, 1993

By Leggate J

In the past many coal mining projects commenced without any consideration being given to eventual site rehabilitation. Now that site rehabilitation is assuming greater importance with changing community expectations, and standards are becoming less negotiable, it cannot be ignored in either the development of mine working plans or economic models. The "unspecified" rehabilitation measures associated with many existing projects will be the subject of debate for some time to come yet. It would be wise to plan for the future. Once an agreeed standard of rehabilitation is accepted, good management involves considering practices which will facilitate eventual rehabilitation at least cost. Without planning for rehabilitation, many mines have adopted practices which are likely to result in very expensive rehabilitation measures and impact significantly on the overall profitability of the ventures. With adequate planning, procedures can be developed which achieve the same short term goals without significantly effecting cash flow but with very significant impacts on the final rehabilitation cost. This paper looks at the disposal of tailings and overburden in the coal mining process. The industry has in the past had an obvious preference for the "perceived" cheaper procedures for waste management such as wet disposal of tailings and high dumping of overburden. There are alternatives. The paper discusses the principles which should be incorporated into tailings and overburden disposal systems and identifies viable alternatives.

Jan 1, 1991

By A Crawford, P Manton

Telfer is a gold/copper operation, currently operating one open pit mine and one underground mine. The ore processing plant consists of two parallel trains involving semi-autogenous mill, ball mill and crusher (SABC) grinding, flotation and leaching. Due to receiving relatively high grade underground ore for over half of its total feed, Train 1 frequently experienced cleaning circuit overloading during high production periods. This resulted in losses in recovery and ineffective concentrate upgrade. As a quick and simple solution, the Train 1 copper flotation circuit was reconfigured to send concentrate from the first two rougher cells directly to the final concentrate and return the cleaner scavenger tailings to the third rougher cell. These modifications have resulted in a 1.4 per cent increase in plant copper recovery with no change in final concentrate grade. Preliminary results also indicate gold recovery has increased by more than 1 per cent since the circuit reconfiguration. Other benefits include less spillage, more friendly circuit to operate and a more consistent metallurgical performance. Focus for the next phase of optimisation is on concentrate upgrade. A number of opportunities have been identified and are currently being investigated, including staged reagent addition, single stage cleaning of the first two copper rougher concentrates, regrinding of the remaining copper rougher concentrate prior to cleaning and process control based on a machine vision system.

Jan 1, 2009

THE following description of the surface plant of the Great Fitzroy Mines is to be understood as having been compiled by a mechanical engineer, who concerns himself more with the various appliances used, their correct construction to enable them to accomplish their prescribed work, and the production and transmission of the power required to operate them, than with the reasons for the physical and chemical processes which those appliances are called upon to assist in carrying out. Hence the metallurgist will not find herein more than the skeleton of the organism, which perhaps he would wish to be clothed with the detailed description of the substances undergoing treatment, in their various combinations, at all stages, and the results attained in separating the valuable constituents from the worthless. So, also, no details will be found of the methods employed by the management for. the purpose of determining by sampling and assaying the nature of the various products obtained.GENERALThe ore being worked at the Great Fitzroy Mine is divided into two classes :-1. Ore that requires concentration before smelting.2. Ore that can be smelted direct.Flow-sheet (Fig. 1) shows in outline the process of treatment to which ore of the first class is subjected, and the writer will endeavour to fill in that outline with some details of the appliances used.

Jan 1, 1911

Although the flotation cell has been under continuous development over the past 80 years, an understanding of the precise roles of a cell in produc- ing the flotation result had evolved slowly. In fact, detailed studies of cell dynamics began only in the 1940s when flotation practice had almost reached the half-century mark. The earliest generalizations related cell capacity to power intensity (hp/vol- ume) (Rose, 1946), and specific operating features such as aeration and power ' consumption to impeller submergence and operating speed (Read, 1933). In the 1950s hydrodynamic characterization of cells through power coefficients and air flow numbers began (Arbiter and Harris, 1961) and has continued to the present, with increasing industrial use of these concepts (Degner, 1982; Degner and Treweek, 1976). Liquid flow measurements in Wemco cells (Degner, 1982) made liquid flow numbers and turnover frequencies available for more complete under- standing of cell dynamics. The present overview of flotation technology is a critique of cell design. The cell process represents the interactions between cell dynam- ics, cell geometry, and ores, with the latter prepared for that interaction through size reduction and reagent treatment. While previous invest- igations of flotation cells have accepted all cell designs uncrit- ically, the present study considers the physical process components that an effective cell must provide, and then compares a limited number of

Jan 1, 1984

By Dixon D. R, Sparrow G. J

Pressure leach liquors from the pressure oxidation of a bulk flotation concentrate prepared from a complex Cu-Pb-Zn sulphide ore were treated to remove iron, either by pressure oxidation (the Hematite process) or with particles of magnetite (the Magnetite process), followed by cementation of various metals with zinc dust to obtain a purified solution from which zinc was electrowon. Satisfactory iron removal was achieved by both processes after neutralisation to pH 4.5 or 5.5. Pressure oxidation of the liquor at 200¦C and 690 kPa oxygen overpressure, conditions similar to those of the Hematite process used in the zinc industry, resulted in the precipitation of the iron as hematite. With the Magnetite process, an iron hydroxide was precipitated onto magnetite at atmospheric pressure and ambient temperature and removed by a magnetic separation step. The performances of both these processes for the removal of iron are compared. It is concluded that the Magnetite process offers considerable cost savings. Other impurities, in particular arsenic, were also removed with the iron in both processes. Cementation at pH 5.2 and 85-90 ¦C with 3.5 g/L zinc dust reduced the levels of copper, cadmium, and nickel to a satisfactory level and subsequent electrolysis in a laboratory cell gave an acceptable deposit of zinc.

Jan 1, 1989

By J Pan, T Chun, D Zhu, Z Guo, J M. Young, T C. Ooi

With the rapid development of the Chinese steel industry, the strong demand for iron ores has led to huge imports of various iron ores from all over the world. As a relatively new force in the iron ore world and an important raw material supplier, Fortescue Metals Group (FMG) has achieved an annualised production rate of 100 Mt of iron ore fines. Typical blends were designed to simulate sinter blends employed in Chinese steel mills, and to determine sintering properties and metallurgical performance of blends comprising FMG Rocket fines in pilot sinter pot. It is shown that the sinter of typical blends comprising 15 - 20 per cent rocket fines possesses excellent sintering properties and metallurgical performance. With Rocket fines substitution for competitor ores in a typical customer mill blend comprising fully imported fines, the sinter productivity and tumble index increased from 1.45 t/m2h and 62.0 per cent to 1.54 t/m2h and 64.0 per cent, respectively, while attaining similar reducibility index and reduction degradation index at lower solid fuel consumption.CITATION:Zhu, D, Guo, Z, Ooi, T C, Chun, T, Pan, J and Young, J M, 2013. Sintering and metallurgical performance of blends comprising Fortescue Metals Group rocket fines, in Proceedings Iron Ore 2013 , pp 519-524 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

As the Mount Morgan electrolytic chlorine plant is the first of its kind installed in Australia, and as the details of this method of producing chlorine have, up to the present time, been kept more or less secret all over the world, the author trusts that this paper may fill a gap in the technical literature of the subject.When an electric current is passed through a strong solution of sodium chloride the following reaction takes place -2 NaCl + 2 H 20 = 2 NaOH + C1 2 + H 2 Chlorine gas is liberated at the anode or entering pole of the current, while caustic soda and hydrogen are formed at the cathode or leaving pole of the current. If the two electrodes be simply immersed in a vessel containing salt and the current be turned on, there will be no result save slight smell of escaping chlorine gas. The passage of the current will have certainly split up the salt water according to the above equation, but as the products would be in juxtaposition they would immediately reunite, and the electrical energy would have been spent without any beneficial result having been obtained. Therefore, the all-important problem in designing an electrolytic chlorine cell is the finding of some effective means of isolating from each other the chlorine and caustic: soda as soon as liberated from the...

Jan 1, 1911

By Mills KW

Coal mine pillar design formulae available to mine planners are typically based on relationships determined for specific site conditions. Application of these methods is difficult when other factors, relating to mining or geological conditions, not specifically addressed in these relationships are encountered. A review of pillar design methods, coal strength properties and relevant field monitoring of pillar behaviour has shown pillar strength and deformational characteristics are extremely sensitive to in situ behaviour of the rock and other material components that make up the coal pillar system. A method has been developed that has been found to provide excellent correlation between existing field data using the strength and deformational characteristics of materials determined in selected laboratory tests. This method is based on definition of the loading conditions, accurate modelling of the strength, confining conditions and deformation occuring in the roof, floor and coal seam and definition of the in situ strength of coal based on underground monitoring of appropriately sized coal pillar. The design method is considered to provide an accurate and rigorous pillar design method that will give mine planners a more rational mine design capability which is based on the mine geometry and geological setting of the operation. It is envisaged that availability of such a method will allow significant optimisation of pillar layouts and more closely define the geological and mining issues that relate to pillar design optimisation.

Jan 1, 1992

By Clark GH

Batu Hijau is a porphyry copper-gold deposit located on Sumbawa Island in the western Banda Arc of Indonesia. The deposit has been evaluated from 54000m of drilling in 105 diamond drill holes over a surface area of 1.2km2 and to a depth of 1000m below surface (412m below sea level). A provisional plan is being evaluated to mine 642 million tonnes at an average grade of 0.61% Cu and 0.55g/t Au (variable cutoff) from an open pit in the higher grade portion of the resource. The deposit is associated with a caic-alkaline intrusive complex that was emplaced in a thick sequence of andesitic pyroclastic rocks. The oldest and most widespread intrusion is porphyritic to medium-grained, equigranular, quartz hornblende diorite. At Batu Hijau the western diorite contact zone was intruded by two phases of tonalite. The older tonalite is a stock increasing from 200m diameter at surface to 500m at sea level. It consists of quartz, plagioclase and hornblende phenocrysts set in a groundmass of similar composition. A younger tonalite intrudes the tonalite stock, quartz and plagioclase phenocrysts are more abundant and it has a finer groundmass than the older tonalite. Brecciation occurs near the older tonalite contacts but there are no breccia pipes or late-stage features such as pebbldykes or postmineralisation intrusive rocks.

Jan 1, 1995

IN this paper the author's intention is to convey a brief resume of the lead flotation treatment and lead flotation machines, which have replaced the May jigs and Wilfley tables at the plant of the North Broken Hill Ltd., and converted this mill into an all-flotation plant.Attention is directed to the fact that this drastic change from semi-gravity to all-flotation treatment, has been successfully accomplished without resorting to finer grinding than that previously in vogue for Wilfley table concentration, viz.: 10% to 16% plus 40-mesh I.M.M. screen.From the figures now available it is manifest that the scheme of all-flotation concentration-new as regards its successful application to Broken Hill ores is resulting in considerably higher-grade lead concentrates, and is substantially decreasing charges for labour, stores, and maintenance.The new treatment is far-reaching in its simplification of plant, as evidenced by the idle jigs and tables, and the results being obtained by North Broken Hill Ltd. may possibly influence metallurgical practice generally in Broken Hill.The outstanding features of the treatment are:(1) The coarseness, and high grade of lead concentrates obtainable.(2) The low time factor required for flotation.(3) The plant capacity, and the simplicity of its operation.(4) The low horse-power consumption.(5) The small cost for reagents used (not exceeding 3d. per ton of ore).

Jan 1, 1930

By P Fines, D J. Williams, G W, S Miller

This paper presents the results and findings of geochemical and mineralogical testwork conducted on samples collected from waste rock dumps at two mine sites, located in South Carolina, USA (Site 1) and Sudbury Ontario, Canada (Site 2). Important aspects of the relationship between the physical and geochemical aspects of the dumps are also presented. The overall aims of the project were to 1. determine if the physical and hydrological nature of the waste-rock dumps had any impact on the geochemical and mineralogical characteristics of the dump materials; and 2. to identify key implications for dump construction for ARD control. The results of geochemical and mineralogical tests indicate that the waste rock at Site 1 had undergone significant in-dump weathering and was relatively advanced with respect to ARD evolution. In contrast, the waste rock at Site 2 had undergone some weathering, however still contained a considerable amount of sulfide minerals. Testing also suggested that flushing of oxidation products at Site 2 had been limited, which therefore promoted the storage of oxidation products at the site. In addition, materials that had a D50 particle size in the range of 5 mm to 30 mm appeared to be more readily flushed than samples that had a D50 particle size of 30 mm. This suggested that preferential water pathways may have developed within the dumps at both sites.

Jan 1, 2003

The distribution of p(~rphyt1 copper deposits, in time as well as place, is used to propose an occurrence model based on the genesis models of Sillitoe and Rona. A magmatic source of the metals is accepted. The characteristic metallogenic epoch and the migration of the mineralization event along an elongate metal province are explained as the result of subduction of an obliquely- oriented strip of mineral-enriched material on the oceanic plate. Two mineral-enriched trails emanate from a hot-spot source of high-intensity hydrothermal activity in an oceanic rift. Because the whole plate system moves relative to hot spots, the hydrothermal source appears to migrate along the rift, and the two trails are not parallel to transform faults, but form a broad "V" centred on the hotspot. Source loci are spaced at intervals of about 3000 km, resulting in the possible repetition of metallogenic epochs, in a subduction zone province, at about 100 m.y. intervals. The position of the mineral-enriched strip can be found graphically, given ages of a series of deposits in a province, and the plate convergence vectors. This knowledge provides an exploration tool at regional scale and, by reflection across the rift, the potential for exploration is extended across oceans. The model has implications for commodities and deposit types other than porphyry coppers.

Jan 1, 1987

While, in the past, a great deal of attention has been focussed on technical issues and the performance of explosives in rock, the explosive user, an essential link in the chain, has often been neglected. In the mining industry, too often, the benefits of excellent technical work have been degraded over time due to the lack of definitive and documented control. Using the principles of quality management a quality training system was developed and implemented for management of explosives use at Gunpowder Copper Ltd (GCL). This paper describes the structure of the system, its development and implementation, and contains practical advice and information for managers responsible for blasting and charge crews. The paper is in four parts: I Quality systems. A brief overview of the relevant aspects of total quality management that apply to explosives use. The requirements for documentation, management and auditing are explored. 2. Training for competency. The five essential elements of Competency Board Training (CBT) are examined, including auditing. 3. The Gunpowder Copper system. Implementation of the complete training system. Documentation and its control, auditing, instructions for operators, management responsibility and means of obtaining operator ownership are amongst the issues raised. Reporting requirements are the means to effectively manage change are described. 4. Summary. The paper concludes with the tangible benefits seen by Gunpowder Copper through the adoption of a quality training System.

Jan 1, 1995

By Leach B. G

A geostatistical study was made of diamond drill hole intersections within 18CC stope block at the C.S.A. Mine, Cobar, N.S.W. The stope block is located in 18CC orebody which is a massive sulphide - multiple vein, Copper-Zinc type, lacking clear definition on gangue mineralogy, base-metal assays and total sulphide considerations. Of the variograms constructed for inter- section width and copper, lead and zinc grades and accumulations, only zinc displayed behaviour amenable to model fitting and kriging procedures. Zinc grades were calcu- lated for sub-blocks comprising the total stope block and comparison with equivalent grades determined by traditional methods showed them to be generally less extreme in the highest and lowest grade sub-blocks. The total-block grades derived by the two methods were almost the same. It is suggested that the failure of copper to show variogram continuity might reflect the difficulty in defining the actual 18CC orebody, a proposition which is supported by the poor continuity in the variogram of horizontal width. In the case of lead the poor continuity may be due to the frequent manner of occurrence of galena as coarse grained patches of limited extent. The results of the study, did not provide a convincing reason to depart from the traditi- onal methods of grade estimation at the C.S.A. Mine.

Jan 1, 1979

By C Ward, U Mueller

Compositional geostatistics is an approach developed to ensure that the constant sum constraint induced by geochemical iron ore analysis is respected in estimation and simulation. Jack-knifing and cross-validation were used within this framework to compare the results from ordinary cokriging of the additive log ratio (alr) variables with those from conventional ordinary cokriging. Two methods were used to back-transform the alr estimates: the crude additive generalised logistic back transformation and numerical integration via Gauss-Hermite quadrature. Previous work on a blasthole data set from a Yilgarn iron ore mine showed promising results, with the Gauss-Hermite quadrature method returning results comparable to ordinary cokriging from the point of view of bias, but superior in that the constant sum constraint imposed by geochemistry of the data was honoured. Other practitioners have noted that the linear interpolation of non-linear log ratio transformations will result in biased results, and that this bias can be masked in a (grade control) setting where the spatial density is high. To test this assertion, the methodology has been extended to successively lower spatial density data sets. The results and applicability to routine iron estimation are discussed.CITATION:Ward, C and Mueller, U, 2013. Compositions, log ratios and bias - from grade control to resource definition, in Proceedings Iron Ore 2013 , pp 313-320 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Sen G

An amount of explosives, whether it be cylindrical, spherical, etc in configuration, with a hollow cavity in one face or end is known as a hollow or shaped charge. When this charge is initiated, a focussing of explosive energy will occur within this cavity. This focussing, or concentration of detonation products creates an intense localised force greater than just the simple detonation of a conventional explosive, (without a hollow cavity). If this hollow cavity explosive is directed against a target material this concentrated force is capable of creating a deeper penetration than the same amount of explosive without the hollow cavity. If a metallic liner material is used in the hollow cavity, upon detonation of the explosive this liner will form into a high velocity penetrating jet. Depending on the explosive type and the liner material's configuration the jet tip can travel up to 10 km/s. Linear shaped charges were developed using the abovementioned shaped charge concept but instead of being formed about an axis, they are elongated and constructed along the principal axis. Therefore instead of creating a narrow circular penetration jet, it forms a thicker planar cutting jet ideal for linear cutting purposes. Using Linear Shaped Charges (LSC) for pre-splitting is expected to result in more accurate directional fracture propagation, while minimising lateral micro fractures in the surrounding rock mass which is required to remain undamaged.

Jan 1, 1995

By Pratt V, Davis K

Challenges facing middle management in the 1980's and beyond are not confined to business matters such as industrial relations, government and legal constraints, corporate takeovers, and commodity marketing. More particularly they deal with people issues and the interrelationship of corporate/ family relationships. There is a need for corporations to acknowledge the growing conflict between corporate/family roles being brought about by such matters as equal opportunity, double professional marriage partnerships, personal mobility and the increasing stress faced by managers as a result of current demands and expectations being placed on them. While the main responsibility for managing professional life as well as the relationship between professional and private life rests with the individual executive, corporations nevertheless have a major responsibility to assist these executives in this management process. Corporations in Australia are taking steps to address this situation but much more needs to be done. This was highlighted in the March 1985 "Middle Management" course with its associated Spouses Programme presented jointly by Australian Mineral Foundation and The Australian Administrative Staff College. Effective communication is at the heart of the matter but no amount of training on this subject will bear fruit unless there is an associated commitment by executives to improve the effectiveness of their communi- cation process both in their corporate and family roles.

Jan 1, 1986