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This paper summarises the influence of slurry rheology on the grinding throughput of batch laboratory and continuous plant-scale mills operating in open and closed circuit configurations. The results of controlled changes in percent solids, particle size, slurry temperature, and viscosity control chemicals are demonstrated. An underlying rheological explanation of the above factors is offered which involves tying the specific rates of breakage that are occurring in the mill with the specific rheological character that the slurry is exhibiting at any given set of operating conditions. Some industrial scale operating guidelines are presented which have proven useful in increasing the net pro- duction capability of grinding circuits.

Jan 1, 1978

In 1556, Agricola noted that "a prudent owner, before he buys shares, ought to go to the mine and carefully examine the nature of the vein, for it is very important that he should be on his guard lest fraudulent sellers of shares should deceive him"(1). In today's world, the owner rarely has the opportunity to visit the mine and, instead of reading about the `nature of the vein' in annual reports, prospectuses, government publications, et cetera he sees the words `reserves' and `resources'. Unfortunately, the subject of reserves and resources has become increasingly complex and Canadians, along with their counterparts in Australia and elsewhere, are still struggling with definitions which will attempt to cover all conceivable circumstances from national or regional resource endowment to the material to be extracted next week from a given stope or open pit bench. The providers and recipients of reserve and resource data are: - Government agencies who are concerned with questions of national endowment, strategic use of raw materials and other questions of public policy. - Stockholders who have a vested interest in the basic assets of their companies. - Financiers who are concerned about the security of their loans. - Regulatory bodies whose function is to protect a frequently naive investor from unscrupulous practices. - Management, at head office and on-site, who need basic information for decision-making, whether it be to open up a new mine, expand or close an existing operation, acquire or merge with other entities, or, more mundanely, for routine mine planning. To satisfy their demands with unanimously accepted definitions is a formidable task but, it is my impression that, little by little, a concensus appears to be growing within the industry.

Jan 1, 1987

By D Thornton, B Smith, S Demey

Mine to Mill (MTM) optimisation, a total systems approach to the reduction of energy and cost in mining and mineral processing operations, is well-established technology. However, successful applications of MTM optimisation have been largely confined to gold, copper and lead/zinc semi autogenous grinding (SAG) operations, where the goals of tweaking the blast design to increase fines and hence throughput through the mill have been relatively easy to meet. The application of MTM optimisation in a more demanding environment, like that of a multi-stage crushing and screening aggregate operation, was conceived as part of a Department of Energy (DOE) initiative in 2004, aiming to reduce the energy consumption in the US aggregates industry. Two quarries operated by the Luck Stone Corporation of Richmond, Virginia, were selected for the demonstration sites. Dealing with ore variability and a requirement to maintain a fixed feed size distribution to the tertiary plant, whilst still aiming to increase yields of saleable products, presented some unique challenges. Despite these variables, the implementation of the MTM approach at Luck StoneÆs aggregate plant in Pittsboro, North Carolina, has led to a tangible improvement in productivity, particularly in the primary and secondary plants. The successful outcome was dependent upon several key factors, including reliable blasting and processing models, careful analysis of the rock conditions and plant configuration, understanding and buy-in from the Luck Stone operations staff, excellent collaboration with Virginia Tech staff and students, and long-term monitoring made possible through comprehensive PLC logging. This paper presents a review of the work conducted at the Pittsboro quarry and highlights the key reasons behind the successful implementation of the MTM approach in a complex plant environment.

Jan 1, 2007

The T33-34 blast, the first major blast at Mount Isa Mines, broke 1,360,000 tonnes of copper ore using 349 tonnes of explosives. The original concept of firing T33, T34, T35 and U37 separately was changed during the life of the project due to adverse ground conditions. These conditions also caused the stoping method to be modified after the firing of the stopes had started. To stabilise the two stopes T33 and T34 where large fall off was occurring, rib pillars were left in the original slot. This caused the blast design to be more complex as these rib pillars had to "lead" the blast. The implication of such a large blast on the underground and surface environment was thoroughly investigated and precautions taken. The charging time of the blast was six weeks. Hook-up was started four days before the blast and continued until two hours prior to the blast. Detailed scheduling was carried out of other work that had to be done in the 24 hours before the blast to ensure that there were no delays in the firing.

Jan 1, 1977

By Mikula PA

This paper presents the results of in-situ and laboratory investigations into a mining method which utilises conventional continuous mining techniques to carry out two passes in thick coal seams, resulting in the development of stable pillars with relatively small width dimensions and heights up to 6 m. Geotechnical investigations included structural mapping, brightness logging and standard laboratory testing. Virgin stress was measured using overcoring techniques. Two approaches to pillar design were used in the study. These were; pillar design based on empirical formulae and laboratory testing, and pillar disign using calibrated mathematical models. A trial panel was developed at 300 m depth to study pillar deformation and stress changes due to mining. The extent of rib deformation was studied using borescopes and extensometers. In-situ geotechnical measurements were used to calibrate displacement discontinuity and finite element mathematical models of the coal seam. These models were then used to predict the behaviour of a small panel of pillars which were to be developed to 6 m height. The mining method was shown to be feasible provided adequate rib support was installed. The benefit of rib support was found to be two-fold, in that it increased confinement of the pillar in zones of low horizontal stress, while reducing horizontal stress relaxation in zones of high horizontal virgin stress. The possiblity of roof control by designing the small pillars to yield on retreat is discussed.

Jan 1, 1986

Goodenough and Fergusson Islands, in eastern PapuaNew Guinea, lie in an area of crustal extension on the western end of the Woodlark Basin seafloor spreading system. The islands are made up of a number of mountainous domes of complexely deformed basement, and these are intruded by large bodies of granodiorite. The domes are bounded by curved shear zones and faults dipping outwards at angles of around 25 to 45¦. The cores of the domes contain lower crustal rocks of eclogite and granulite facies, these rocks have undergone retrograde metamorphism in the outer sheared zones. Movement indicators on the shear zones indicate a complex moverm.-It geometry which does not fit the models proposed by earlier workers. These dome-like structures are similar to the metamorphic core complexes of the western United States Cordilleran region, however there are a number of aspects which do not fit with the models proposed for the development of metamorphic core complexes. Uplift of the metamorphic basement probably resulted from a combination of forces associated with the extension of the crust and the intrusion and emplacement of granodiorite plutons.

Jan 1, 1990

The treatment of mixed lead carbonate and lead sulphide concentrates at Mount Isa presents a problem which is unique ,in the lead smelting world; a problem whose solution is far from simple, and is not yet complete. Two years of study under plant conditions have definitely proved, however, that a most satisfactory sinter can be made in a single-pass roast.The object of this paper is to present a brief record of the development of the single-pass roast and a resume of current practice in the smelting plant. The sintering operation is discussed in greater detail, as it is upon this phase of the work that every item in the smelter operating programme depends.The smelter, to-day, presents a very much simplified layout, equipped for economical, straightforward operation, requiring, however, very careful and constant supervision, due to the extreme delicacy of the sintering operation and to the rapid and wide variati9n in the nature of the concentrates which are to be handled.

Jan 1, 1933

The Mount Morgan eopper-gold orebody is contained within a series of Mid-Devonian volcanics which occurs as a roof pendant within Permian granite. The ore minerals comprise pyrite, chalcopyrite, and local aggregations of magnetite and pyrrhotite. Silver-rich gold (electrum) is disseminated through the ore usually in ultrafine to sub-microscopic dimensions. Accessory minerals include marcasite, digenite, chalcocite, covellite, sphalerite, bismuthinite, molybdenite, calaverite, petzite, and cassiterite.Very minor accessories include cubanite, tetrahedrite, galena, arsenopyrite, hematiIe, goethite, and rutile. The gangue minerals are quartz, predominantly, with minor amounts of chlorite and sericite.Study of microtextures of a representative suite of specimens from Mount Morgan does not reveal any criteria indicative of metasomatic replacement but does show, in the case of pyrite, evidence strongly suggestive of annealing recrystallization. Other textures in pyrite indicate porphyroblastic growth of the iron sulphide.It is inferred that the Mount Morgan orebody is genetically related to the volcanic rocks and was later contact metamorphosed by the intrusive granite or by the series of intermediate to basic dykes that transect inmine area. On this basis the Mount Morgan orebody would be a contact metamorphosed volcanic hydrothermal deposit emplaced, according to recent studies, along a pipe-like zone of brecciation.

Jan 1, 1967

Any future developer of underground mining on the Bendigo goldfield will need to understand the unique geology and gold occurrence of this field. The development and sloping system employed will be primarily designed around these unique features. Modern techniques and equipment used in narrow vein mining will be applicable in this situation.The purpose of this paper is to examine the important geological features of the field as well as the known historical occurrences of the type of gold deposition in the ore bodies. This information will point to a system of development and extraction which will accommodate these features.

Jan 1, 1993

The development of present methods of pillar extraction has evolved from the very earliest of hand mining operations which were limited in scope by venti- lation and transport considerations. Conservation and safety considerations also have led to the current shortwall operations with conventional equipment and powered supports. The shortwall methods have had significant effects on safety, costs, con- servation, flexibility, and other aspects of pillar extraction. The present stage falls short of the ideal but is some guide to prediction in what direction may lie the ideal methods for the future.

Jan 1, 1974

With the post-war expansion of mmmg activities on its Western group of mines, the management of Lake View and Star Limited has commenced a project for the improvement of underground ventilation.The major part of this project is to provide adequate return airways for the ventilation of the deep levels. To this end, the Ivanhoe South Extended shaft is being enlarged, and ultimately an exhaust fan with a capacity of 180,000 cu. ft. of air per minute will be installed at the shaft collar.Prior to 1932, the shaft was used exclusively for baling water from the 800 and 2,000 ft. levels. These two levels are the only ones connected to workings from the Horseshoe lease. After the installation of pumping plant at the Horseshoe Main Shaft, baling was discontinued, and the water was graVitated from dams to the pumps on the 1,000 and 2,000 ft. levels.Water makes into the shaft, through a series of fault planes, between the 600 and 1,500 ft. horizons. The total flow is 16 gal. per minute, of which approximately 7 gal. per minute graVitates to the 800 ft. level. As a big proportion of the water dropped uncontrolled through the shaft, a downcast current of air approximating 20,000 c.f.m. was induced. This air ventilated a limited area of workings in the Horseshoe lease, between the 2,000 and 2,360 ft. levels.In 1938, it was decided to reverse the direction of the airflow in the shaft. Work was carried out to pipe the...

Jan 1, 1948

By Harraway D. H, Draper N

The association of graphite with a fine grained pyrite in the Mount Isa lead-zinc ore was investigated from mineralogical and metallurgical standpoints. The pyrite has been partially or completely replaced by galena and to a less extent by sphalerite, pyrrhotiteand chalcopyrite with the retention of graphite films or inclusions. During lead flotation the graphite imparts a spontaneous flotability to all associated minerals, resulting in a low grade fraction, which we call the carbonaceous fraction, floating with and diluting the lead concentrate. In times of low metal prices this fraction seriously reduces the economic value of the lead concentrate. A flotation procedure was developed to upgrade the carbonaceous fraction separately, producing an economic concentrate and a tailing.INTRODUCTIONThe lead concentrate produced from Mount Isa ores can vary from 20 to 50 per cent lead, depending on the locality in the mine from which the ore is obtained. Variations of this order are independent of ore grade and lead recovery. The large variation is related to the presence in the ore of a variable fast floating low grade fraction known locally as the carbonaceous fraction because of its association with graphite. During conventional lead flotation with sodium ethyl xanthate the carbonaceous fraction floats rapidly and unselectively with normal Mount Isa galena.The paper discusses mainly the examination and treatment of an average carbonaceous fraction, defined here as the fast floating material in the mill feed of late 1956. The ore was drawn from the Mount Isa Black Star orebodies. The fraction represented about 5 per cent of the total ore...

Jan 1, 1961

By Hunter W. H, Wilson I. P, Craig R. W

In September 1988 the Imperial Smelting zinc - lead blast furnace at Avonmouth England, was uprated from its then 52 week annual rated capacity of 90 000 tonnes/year of furnace zinc to 110 000 tonnes. In order to provide sufficient extra feed the sinter plant was likewise uprated in April 1989 by increasing the blowing rate of the sinter/acid plants from 100 000 to 120 000 Nm3/h, effectively a 20 per cent increase. In the 12 months after the uprate zinc production was only 85 000 tonnes. Two years after the uprate zinc production had increased to 100 000 tonnes, but it was not until January 1992 that a rolling 12-month zinc production of 110 000 tonnes was consistently achieved. This paper describes the problems encountered with the uprate and how they have been or are being overcome. It deals chronologically with events starting with the restart of the ISF at the end of 1988 and covers the following issues and their resolution: 1. Initial shortages of sinter due to an offset in uprate timing. 2. Greater difficulties in operating the larger furnace particularly on start-up, the greater tendency for iron production and serious slagging problems. 3. Coincidental timing of deleterious trends in slag chemistry. 4. Refractory problems in the furnace shaft and condenser. 5. Shortages of sinter due to commissioning problems with the wet gas and sinter tip end fans, and difficulties in obtaining sufficient sinter hardness. 6. Unrealised full benefits of the sinter-acid uprate due to a late change in design to dispense with sinter gas recirculation, but offset by successful use of oxygen. In a planned maintenance stop in September 1992 further improvements to the furnace design were carried out to resolve the refractory problems, and with improvements to the sinter plant the furnace zinc output capacity is planned to rise to a rate of 120 000 tonnes/year within two years.

Jan 1, 1993

By B Liu, W J. Zhang, S Saydam, B Li

Rock bolts are commonly used to reinforce ground in underground mining and civil tunnel environments. Rock bolts serve two main functions: i) they suspend large, loose blocks of ground, and ii) provide a protective pressure arch to restrain the deformation in an excavated void. Automated and precise tracking of rock bolt positions can assist with the operational success of ground support by reducing the amount of labour required in current manual practices. A point cloud is a large list of x, y and z coordinates in three-dimensional space, that when visualised, show a precise 3D representation of a physical environment. Point cloud data can be collected using accurate LiDAR scanners. These scanners can be mounted on a stationary tripod or on a moving vehicle. A key way point cloud data is used is in the bolt detection project being completed in conjunction with UNSW Sydney, which aims to provide an automated location of underground rock bolts from LiDAR scans. The immediate challenge with identifying rock bolts is that they constitute a very small portion of the data set amounting to approximately 0.01 per cent of some of the collected civil tunnel data. The process of detecting rock bolts from point clouds therefore requires a quick elimination of large background data while still preserving the bolt data. A further challenge is that the geometry of underground environments can often be very complex and non-uniform. To overcome these challenges, a two-step coarse to fine deep learning approach is taken. The first step is a coarse background elimination step aimed at removing as much of the background data as possible. The second step is a finer classification method, which uses deep learning to further segment the bolts from the remaining background. Additionally, a computer vision module is being implemented, which is expected to increase the detection rate by adding another dimension to the training data set.

Nov 29, 2022

By Grader F. E

A linear motor properly wound can serve as a mechanism for separating paramagnetic sulphide minerals, like pyrrhotite, from other sulphides and associated gangue minerals. The effective- ness of separation depends on the energising current of the separator, the frequency of the a.c. cycle, and the particle size of the minerals. The speed of travel of the minerals over the surface of the separator is also a function of particle size, and appears to be constant. The movement of pyrrhotite, magnetite and iron filings of comparable size fraction (150um +74pm) on the linear motor surface has been observed using a cine camera. An attempt has been made to give a theoretical basis for the movement of the particles by calculating the minimum electrical energy required to move them. Further, the rate of decay of magnetic moment of the particles has been estimated for magnetite and it has been found that sufficient residual magnetism existed in the particles after they had been exposed to the first half of an a.c. cycle for them to have like polarity with the second half of the cycle. The particles are therefore repelled from the motor surface every second half of the cycle. This repulsion due to remanent magnetism is the probable cause of particle movement over the linear meter surf, e.

Jan 1, 1980

By Just GD, Gillies ADS

There is an increasing need for reliable and comparable coal resource data and it is necessary to standardize the traditional classification procedures by quantifying the three basic evaluation criteria of economic feasibility, geologic assurance and recovery. For well documented deposits, geostatistical methods can consider- ably improve classification quality. A geostatistically based algorithm for classifying coal resources within the current Queensland and New South Wales codes has been developed. Application of the method in classifying resources from a number of seams exhibiting different structural characteristics is assessed. The method is found to give classification results which closely reflect the error associated with an estimate of resource quantities based on current sampling densi- ties. It requires a careful geostatistical analysis with emphasis on geological awareness. Resource category restrictions must be arbi- trarily assigned and remain constant for all deposits being compared. Engineering judgement is needed and interpretation may be required with isolated and peripheral blocks.

Jan 1, 1987

By T D. H McGrath, G Wardell-Johnson, E A. Oraby, W Staunton, A R. Bax, J J. Eksteen

"Gold ores often show significant inter-domain variation with respect to the gravity recoverable gold (GRG) content and the leach behaviour of the non-GRG component. Liberation assessment is extremely difficult for gold due to its malleability and the high sampling errors and poor test reproducibility resulting from gold’s high specific gravity and the low metal concentrations that occur in most gold ores. The use of microscopic techniques for the liberation assessment of gold is also impractical due to the high number of sampling errors and high cost of analysis.Curtin University’s Gold Technology Group has developed an online carbon-in-pulp/carbon-in-leach (CIP/CIL) simulation model called SIMCIL, which has been used since 1999 to model and simulate industrial leach-adsorption circuits. Recently the model has been upgraded to include an integrated liberation-leach modelling (ILLM) approach, which can be used to evaluate the impact of various process parameters (such as grind size, bleed to gravity etc) and circuit configurations on leach-adsorption circuit behaviour and overall plant gold recovery. A new time-efficient ore characterisation methodology has been researched and developed to provide the required liberation-leach data used in the ILLM approach, which is implemented online for the modelling of gold operations. The ILLM characterisation methodology, test work data analysis, interpretation and application of the ILLM test work data are discussed.CITATION:Bax, A R, McGrath, T D H, Eksteen, J J, Staunton, W, Oraby, E A, and Wardell-Johnson, G, 2016. An Integrated Liberation-leach Model and Ore Characterisation Procedure for Gold Ores, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 315–320 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By C L Humphrey

Biological monitoring programs for environmental protection require techniques that will provide both early detection of possible adverse effects, and assessment of the ecological significance of these effects. Monitoring techniques must include responses sensitive to the impact, that can be subjected to rigorous statistical analysis and for which statistical power is high. Such issues in baseline research of 'what and how to measure?' and 'for how long?' have been the focus of a program being developed to monitor and assess effects of mining operations on the effectively pristine, freshwater ecosystems of the Alligator Rivers Region (ARR) in tropical northern Australia. Application of the BACIP design, utilising a form of temporal replication, to univariate data (single species) and multivariate (community) data is described. For new ventures in Australia (such as mining), monitoring programs should be designed to establish with high probability that an impact on the ecosystem no greater than a prescribed amount has gone undetected - as opposed to simply allowing development to continue as long as 'proof' of impact is not available. Such a precautionary approach represents a shifting of the 'burden of proof' and would require with the BACIP design, a minimum number of baseline years in order to achieve some desired level of statistical power in a test for impact. Power analyses conducted on two to five years (depending upon the technique) of baseline data from streams of the ARR indicate that the BACIP design would not impose developmental constraints on mining and that a policy of reversal of the burden of proof would provide the cornerstone required for managing such development in an ecologically sustainable manner.

Jan 1, 1994

By Brown N. R

This paper attempts to highlight some of the problems encountered in the economic exploitation of the deeper coal seams by opencast mining methods. The major cost elements of three methods of overburden removal are examined in relation to the overall cost of winning coal from deeper-lying coal seams. The three overburden removal methods examined are dragline stripping and two systems combining dragline stripping with shovels and trucks at varying depths of overburden. A dragline is, undoubtedly, the most cost effective system of overburden removal for depths of up to 30 metres but it is suggested that, when dealing with incremental overburden depths in excess of 30 metres, engineers should consider carefully the possibility of using a shovel and truck operation, or other system, to augment the use of a dragline.

Jan 1, 1986

NEARLY all problems in mining engineering involve the transport and distribution of materials from place to place, and in general the most economically managed mines and plants are those in which the transport of materials has been carried out most efficiently. Of all these transport problems, the hoisting of ore out of the mine and the distribution of same to the various treatment works is perhaps one of the most important. It is proposed in the present paper to traverse the conditions,affecting the location, scale of operations, and design of the main shaft and head gear at the Mount Morgan mine; afterwards describing the designs and workings of the shaft house, winding engine, and transport from the shaft house to the treatment works.LOCATIONWhen the copper-gold ore was developed sufficiently to determine approximately the boundaries of the ore-body, it was found that the existing vertical shafts would be wholly inadequate to deal with the increased quantity of ore required to be handled. It was proposed, therefore, to construct a new shaft, and to handle in this...

Jan 1, 1911