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By Kadoya H, Kondo Y

The Harima works were established in 1964 and started operation in 1966. The initial capacity was 3500 t/month of zinc and 1500 t/month of lead. Until 1990 a lot of improvements had been made and the capacity had increased 6600 t/month of zinc and 2200 t/month of lead without enlarging the furnace size. During the ten weeks campaign shut-down at the end of 1990, many modifications were carried out including the enlargement of the furnace shaft area. By these changes, the capacity has gone up to 7500 t/month of zinc and 2500 t/month of lead. In the sinter plant, the amount of SO2 rich gas supplied to the acid plant was raised to 50 000 Nm3/h from 43 500 Nm3/h. An electrostatic precipitator was adopted instead of a venturi scrubber to clean the rich gas. Oxygen enrichment has been continuously operated since August 1991, because the furnace capacity is more than the rate of sinter production. Utilisation of the sinter plant is high being as much as 97 per cent and the sulphur burning rate has been increased. In 1990 the furnace was replaced except the hearth. The shaft area was enlarged to 19.4 m2 from 15.3 m2. The target blast was designed to be more than 36 000 Nm3/h. Tuyere layout was changed to prevent slag breakouts. Due to these modifications shaft condition has been very good. Automatic launder jacket cleaners were installed to increase the lead cooling efficiency. Many other improvements and developments were also made. Coke powder injection from the tuyeres has been successfully operated since April 1987.

Jan 1, 1993

By J J. Wilkinson, C J. Ha, R J. Herrington

The Pic de Fon iron oxide deposit is a potential major new source of iron ore, located at the southern end of the Simandou range in eastern Guinea on the West African Craton. The deposit is hosted by banded iron formations (BIFs) within a supracrustal sequence, which lies unconformably upon a crystalline basement. The host BIFs and shales have been metamorphosed up to staurolite-grade itabirite and phyllite respectively. Stratigraphic relationships are obscured by polyphase deformation, although the sequence appears to comprise a lower phyllite(-minor quartzite) unit and transitional phyllite-iron formation overlain by three itabirite units. It is the itabirite units, selectively enriched to iron grades in excess of 65 per cent Fe (with low deleterious elements), that constitute the Pic de Fon deposit. Samples acquired from exploration diamond drill holes and outcrop across the deposit have been collected to investigate the Pic de Fon lithologies and iron-rich material types. Initial research techniques have included geological mapping, reflected light microscopy, x-ray diffraction (XRD) studies and ICP-AES geochemistry. The aim is to develop a model for deposit genesis that may assist future exploration and deposit exploitation planning. Results to date have identified a variety of hematite textures, which include recrystallised trellis, interlobate and granoblastic hematite after magnetite. In addition, fine-grained bladed to acicular microplaty hematite appears to both replace itabirite banding and infill porosity. Field relationships indicate a structural control of microplaty hematite development. Geochemistry and XRD results suggest a loss of silica with negligible iron addition during the conversion of itabirite to ore grade mineralisation. The enrichment process(es) is also accompanied by a gradual increase in K, Mg, Na, (Ca and Al).

Jan 1, 2005

By J E. Everett

Maximising ore tonnage at a selected target grade requires that appropriate ore identification criteria be established. Iron ore mining block models may consist of many millions of estimated blocks, each block corresponding to the selective mining unit (SMU), with grade interpolated from drill hole data. Each block can be considered as a potential ore candidate. Analysis of such a huge database can require large computational resources, especially for sensitivity analysis requiring multiple computations. However, an alternative streamlined approach is possible, where the data are compressed to an appropriately smaller and representative subset. The consequent data reduction not only makes it feasible to consider the simultaneous analysis of multiple pits but also considerably speeds up computation, enabling sensitivity analysis of the potential ore tonnage as a function of the required grade. Ore identification criteria can be successfully established using appropriately chosen reduced data comprising less than one per cent of the blocks. The ore identified is virtually indistinguishable in tonnage and grade from the ore that would be selected using the entire block model.Two methods of data reduction are tested: sampling (using a proportion of unaltered blocks) and binning (consolidating groups of blocks to a single average grade). The source blocks are first sorted (such as by location, analyte grade, principal component score, random order or value) before sampling or binning. In this study, the sorting options considered were by location and Fe grade. The effectiveness of each method was evaluated using the block model subsets to select the maximum tonnage of ore at a specified target grade. Block model data from an anonymous Pilbara iron ore project with about one million blocks averaging 1.132 kt were used. The blocks are from multiple resource models, to be blended to a single product. Sampling is shown to be superior to binning because sampling preserves the full variability while binning, although matching the mean block grades reduces their variability.It was found that the appropriately sampled data sets (sorted by location) gave results virtually identical to the results for the full data set, even when the samples comprised less than one per cent of the original blocks. The reduction in computer time to identify maximum tonnage at a specified grade was approximately proportional to the sample percentage. The increase in computation speed greatly facilitated sensitivity analysis. A sampled data set of one-eighth the total block model was used to investigate the effects of changing each of the component grades around the original grade specification. The results of this sensitivity analysis are discussed, and illustrate the potential benefit of carrying out sensitivity analysis in determining feasible and marketable product grades.CITATION:Everett, J E, 2015. Block model data reduction and sensitivity analysis, in Proceedings Iron Ore 2015, pp 263–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

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

A new gold cyanidation assay technique has been proven for a range of ores, where it has demonstrated benefits of being: ò Accurate (reduces the typical range of assay scatter almost three-fold, and avoids common fire assay interferences). ò Fast (under one hour, providing a quantum shift in space requirement and equipment utilisation each bottle roll can provide over 15 determinations per day). ò Simple (suitable for field application, no high skill or experience requirements). ò Profitable (reduced drilling, drilling time, ore misclassification and/or double handling after mining). ò Cheap (far lower cost than Fire or Aqua Regia Assays, ie LeachWELLTM costs around 10ó for a 20 g sample at 50 per cent solids, proportionately greater for larger samples eg $1 for 200 g samples which address most nugget effect problems). ò Relevant (distinguishes economic. ie cyanide-extractable gold, the only unequivocal value to use for true resource definition, mine planning and grade control). ò Robust (rough bucket chemistry of samplers does not seriously affect results). A new development is the provision of LeachWELLTM CAS, a solution, which also contains optimum cyanide and stabiliser concentrations; and offers greater: ò Safety (the dilute cyanide solutions are stabilised to avoid generating toxic HCN vapours; and present no cyanide dust or flying chips to deal with). ò Ease (a single squirt dispenses precise quantities of the entire reagent suite, avoiding multiple weighings). ò Reduction in total reagent costs. An inter-laboratory comparison on nine ore types, using two assay techniques (Fire Assay and Aqua Regia) involving 45 laboratories, has demonstrated that LeachWELLTM 60X assays for the samples tested, were equally or more reliable than typical Fire or Aqua Regia Assays. There is particularly great benefit in applying LeachWELLTM 60X assays to richer ores in comparison to Aqua Regia assays, which appear to be prone to very significant underassaying depending on individual analyst skills, and which often suffer greater nugget effects. The major impacts for heap leaching are that: ò Using the LeachWELLTM assay technique for grade control, ore of marginal grade is not accidentally discarded to waste or visa versa due to the scatter of assay data inherent in typical small charge (25 g) fire assays. ò LeachWELLTM assays very importantly report only that gold which will be recoverable in the heap, viz that which is liberated - an important factor where the coarse crush often leaves ten per cent of gold unliberated. These impacts are of particular importance for many ores (ie most of those recovered from open pit operations and at the margins of rich ore subject to slurry processing) subjected to heap leaching as the oxide zones often present major problems of nugget effects as well as mineralisation that cannot be accurately assigned through interpretation of clear structural controls.

Jan 1, 1994

By Kam KM, Tran B

Statistical techniques of Box and Jenkins (1976) have been used to assess the existing control schemes and determine the dynamics of flash smelting furnace at the Kalgoorlie Nickel Smelter. Pertinent process variables, such as, oxygen flow, flux flow, matte grade and iron to silica ratio in slag, were considered in the analysis using routine operating data collected over two periods of operation. Results indicate inadequate control of some of the important variables. Dynamic characteristic parameters (dead time and response time) between a set of input and output variables were identified to improve optimisation of the existing thermodynamic model used for flash furnace control.

Jan 1, 1996

By G Kennewell

At 11 am Monday 8 September 1997, the successful detonation of the 5/9 Mass Blast at Pasminco - Elura was signified by the subsiding of æMt KevinÆ (a 15 m high earth fill mound). The blast was in response to earlier mine subsidence, which holed through to the surface affecting future stability of underground workings. The blast was a first for Elura which fires small tonnages regularly to avoid rapid oxidation of the ore. This paper discusses the strategy and the considerable planning that went into EluraÆs first blast of this magnitude in order to succeed first time round.

Jan 1, 1999

By A G. L Pratt

Inclined troughed belt conveyors are more frequently being selected from a range of alternatives, which include shafts and trucks for ore haulage in underground mass mining projects. Belt conveyor haulage systems are being operated with lifts exceeding those normally associated with truck haulage systems and approaching the limits of shaft haulage systems. A belt conveyor haulage system, in this context, incorporates subsystems for: crushing,tramp detection and removal, andhaulage. This paper presents details of recent inclined troughed belt conveyor systems for underground mining operations, and explores the application of inclined troughed belt conveyors for the increasing demands of future underground mass mining projects.

Jan 1, 2008

By G A. Challis, A B. Christiel

Microprobe analyses of electrum grains in some Hauraki Au-Ag deposits indicate that gold fineness is in the range of 500 - 800 (50 - 80 per cent Au), but for most deposits the range is usually narrower than this. The electrums contain minor amounts (<0.8 per cent) of copper, arsenic, antimony, mercury, iron, and sulphur. Platinum and palladium were analysed for but were not detected (detection limit 0.24 per cent for Pt or Pd). For some deposits (eg Waihi), the average fineness values for the analysed electrums correspond fairly well with the electrum fineness determined by assay during the historic mining operations.

Jan 1, 1992

Esso-BHP have installed a production supervisory control system that is presently controlling the offshore oil and gas facilities on the Barracouta and Marlin platforms from an onshore master station. This control is achieved with a computerized master station onshore which uses a UHF radio system for telemetry and control.The system is designed to control, monitor, and gather data from a large number of oil and gas production platforms and has flexibility to handle future variations in operating conditions.The system will be extended to the Halibut platform late in 1970 and to the Kirlgfish platforms during 1971.

Jan 1, 1971

This paper sets out to examine the possible relationships between three factors, they are, the rate of growth of world production of minerals, the growth of Australian production and the growth of scientific and engineering knowledge.The first two are quantified, in terms of tonnes and value. The third, an abstract concept "knowledge", requires to be quantified, in terms of manpower.A mathematical model, which has general application, was derived to demonstrate certain axiomatic premises and to define, more precisely, basic concepts related to the philosophy of knowledge.Finally a summary is made of education-cum-industry issues.

Jan 1, 1981

By Peddie F, Low K, Madgwick J, Rajoka M. I, Gutierrez N, Lim C

Percolation irrigation of low-grade quartz feldspar porphyry ore with pH 2.0 H2SO4 at 510 litres/m2/day using particle sizes 1.7 - 6.7 mm in columns measuring 5 cm dia × 126 cm long was used to study effects of interrupted irrigation ('rest' periods) on metal ion release and leaching bacteria. Copper tenors increased approximately 16 fold and bacterial iron oxidation activity three fold following a 14 day 'rest'. A linear relationship between copper tenor and bacterial activity demonstrated that this experimental system was effective for quantitative studies of bacterial leaching in ore colums.

Jan 1, 1981

Whilst the wider community is both a large consumer of mineral products and relies on mineral exports for much of the wealth which sustains it, the community generally has a poor perception of the minerals industry.   The role of professionals and The AusIMM in the "New Economy" minerals industry is reviewed. The new structure of The Institute is vital as we move forward in times of globalisation, rationalism, increasing litigation, criminalisation of risk and increased focus on corporate governance. This address looks forward to ways The AusIMM and professionals of the future are positioning themselves for these and other challenges.

Jan 1, 2001

By C Fearon

This paper discusses the implementation of an underground rail haulage system during a major expansion of the Olympic Dam mine in 1998. The factors affecting the selection of rail haulage are discussed and details are provided on the rail system, which is designed to transport more than 10.5 million tonnes per annum (Mtpa). The reliability of the system during commissioning is discussed, including the decision to manufacture a ædummyÆ locomotive in order to keep the system operational. Finally, reliability improvements made both during and after commissioning are discussed with comments provided on the effectiveness of the system as it operates today.

Jan 1, 2005

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

Jan 1, 1994

By P Ring, B Cooper, C Carr, G Laing

The Nova Ni-Cu-Co Operation, located in the Fraser Range of Western Australia, commenced commercial production in July 2017 only five years after discovery. Owned by Independence Group NL (IGO), the operation has successfully ramped up over an accelerated schedule and currently deploying leading technologies. This paper begins with a description of the Nova Operation, and its journey to achieve full production in such a short time frame. It includes discussions on development and production design, selection of fixed plant infrastructure, and the features challenges of running a low-pressure primary ventilation circuit. The paper also discusses key technologies that have improved overall safety for the underground workforce, and improved operational efficiencies. Investigations continue into the implementation of further technological applications for safety and productivity enhancements. This paper also discusses the findings from a study into transitioning from a diesel to an all-electric underground mining fleet, based on a review of Nova if it were to be developed today with the current EV offerings. The study indicates compelling savings will be available to future mines when considering development design, project schedule, capital outlay and operational savings, and the ‘next Nova’ is expected to be all electric.

Mar 15, 2021

By Tack K

During its 28-year life the MHD ISP smelter has gone through two phases, each of about a dozen years. The first phase was a learning one; in the second phase the lessons were applied and throughput and production rose strongly. Early experience revealed the robustness and the flexibility of the Imperial Smelting Process. The experience was demonstrated by strong increases in the throughput of mixed lead-zinc concentrates and of secondary (oxide) zinc materials. Purchased material quantities rose from 175 000 tonnes/year to 200 000. The required capacity increase of the IS furnace to smelt the higher throughput was achieved by relatively minor modifications; for instance a change to the internal furnace profile gained an extra two square metres in cross sectional area. The furnace hearth area has remained practically unchanged over its entire history. The paper concludes that there is still more potential to be drawn from the process and MHD intends to sustain raw material input at a new level of 240 000 tonnes/year. However, this rate will have to be achieved under the imposition of more stringent environmental and product quality standards than ever before.

Jan 1, 1993

By R Dimitrakopoulos, C Paduraru

The optimisation of mine complexes and related value chains is a challenging problem due to the simultaneous presence of a highly-dimensional decision space, integer decision variables, non-linear constraints and recovery functions, as well as geological and market uncertainty. In addition, if the uncertainty is revealed progressively, then decisions need to continuously adapt to new information, which poses additional challenges. Stochastic dynamic programming is a well-known class of methods for addressing problems where a decision-maker reacts to new information. While simplistic applications of dynamic programming using exact representations would be intractable for any realistic mine planning problem, new dynamic programming methods using approximate value function representations have been successfully implemented in the past to address problems of similar complexity. This work formulates the problem of mine complex optimisation as an approximate dynamic program and presents an application of the resulting method to a gold-copper deposit.CITATION:Paduraru, C and Dimitrakopoulos, R, 2014. Mineral supply chain optimisation under uncertainty using approximate dynamic programming, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 415–422 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By Zichenko ZA, Volkov SV, Shaluhina LM, Emelyanov AF

A method of selective gold recovery from black sands has been elaborated which is based on the liquid phase low temperature chlorination of materials. A liquid agent mixture of sulphur monochloride S2C12 and sulphur dichloride SC12 is used. This method ensures the gold extraction either in the state of AuC13.SC14 complex salt solution or as metal. The kinetics and main physico-chemical parameters of the process (eg density, solid: liquid ratio, temperature) have been investigated. The materials investigated were quartz-insipid ride samples with low sulphur and high iron (up to 70 per cent Fe2O3) contents. Gold recovery is 96 - 99 per cent at temperatures not exceeding 100¦C. Most of the associated minerals remain in the cake. To obtain metallic gold, the resulting solution of the AuC13.SC14 salt after leaching is reduced by hydrazine with subsequent annealing. The elaborated method is remarkable for small energy expenditures owing to low process temperature and a high gold dissolution rate. The solution of sulphur chlorides and other reagents are used in closed cycle.

Jan 1, 1993

By M, C Silveira, C Ellice, D Christensen

Peak Gold Mines (PGM), a member of the Rio Tinto Group, is an underground and open cut gold mining operation located near Cobar, NSW. A multi-phase study was initiated in 2001 in support of developing a dry æmoisture store and releaseÆ cover system design for the PGM tailings dam, which contains potentially acid-forming tailings material. The first phase consisted of characterising the tailings and potential cover material (waste rock from an open cut operation) as well as soil-atmosphere cover design modelling. The second phase involved construction of two cover system field trials on the tailings dam and installation of a variety of field instruments to monitor the hydraulic performance of the test covers during all seasons of the year. Field performance monitoring commenced in April 2002 and will continue for a minimum of two wet-dry climate cycles (third phase), prior to using the field data for calibration and subsequent validation of numerical models developed for the cover system trials (fourth phase). This paper describes the work completed for the first two project phases and also discusses the initial performance of the cover system trials.

Jan 1, 2003