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By H Kurth

Mining geologists utilise many technologies to map, sample, measure, model and plan before and during the mining process. Predicted ore quality rarely corresponds with feed quality determined by process operators. Objectively measuring conveyed material quality accurately in real time avoids disagreements over mined ore quality and generates opportunities to improve mill feed quality.This paper discusses the well proven PGNAA (prompt gamma neutron activation analysis) technology used in the GEOSCAN-M elemental analyser that is ideally suited to measuring composition of primary crushed conveyed material in real time. Representative, continuous, fully penetrative measurements are unaffected by particle size, belt speed, mineralogy, dust or layering on the conveyor. Material can be directed to processes or stockpiles by utilising measurement increments of typically one to five minutes and then activating diverters to direct increments to the correct location. Waste, low-grade or deleterious material can be rejected to waste dumps or stockpiled for later processing. Material meeting a product specification can bypass unnecessary processing. Paybacks in weeks have been achieved for such applications. Process operators are able to control the blend of ores fed into the mill to improve processing performance and use measurements for ore reconciliation and metal accounting. Utilising the technology to upgrade ore quality after mining and before processing is beneficial in improving plant economics.The technology has been successfully utilised in base metals, ferrous metals and industrial minerals. Mining geologists can determine ore quality being produced in real time and modify the ore quality prior to milling. Ore feed quality measurements are also used by process operators in optimising plant performance. The elemental content can help identify geometallurgical domains as well as other major changes in quality, which may affect processing. This paper outlines proven applications and case studies and proposes some innovative applications.CITATION:Kurth, H, 2017. Measuring ore quality using real-time on-belt elemental analysis – more than grade control, in Proceedings Tenth International Mining Geology Conference 2017, pp 213–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Kanchibolta S. S, Brunton I, Tapia-Vergara F

The Split digital image processing system has been implemented in three Australian mines for analysing the size distribution of rocks from the images taken from muckpiles, conveyor belts and tipping trucks. This paper presents an overview of t

Jan 1, 1998

By Nicol SK, Engel MD

Ion flotation involves the adsorption of ionic species, in association with surfactant molecules, at the surface of rising gas bubbles, for the purpose of recovering and concentrating those ions. The objective of this study was to optimise the ion flotation process using a heap-leach liquor, containing gold cyanide, and the surfactant cetyl trimethyl ammonium bromide (CTAB). The aim was to minimise the surfactant reagent dose, maximise the throughput of feed liquor in the process, and satisfy the dual constraints of a high gold recovery and a high volume reduction factor. Development of a first order model of the ion flotation process formed the theoretical basis for the test program procedure and the interpretation of the results. Batch tests were used in order to determine the ultimate recovery curve for the heap leach liquor-CTAB surfactant system. The results indicated that a surfactant dose of about 0.083 g/l would be necessary in order to achieve a satisfactory gold recovery. Continuous tests were then performed on a small-scale pilot plant at the Newcastle Laboratories. The optimum result achieved was a gold recovery of 85 per cent, a volume reduction factor of ten, and a feed throughput of 2.3 m3/m2-h. Recent work also indicates that very much higher volume reductions can be achieved using a larger diameter vessel. The improvement may be a consequence of a reduction in wall effects and hence an improvement in foam drainage.

Jan 1, 1993

By A M. Wala, H W. Wu

A research project incorporating a number of mine site exercises to reduce the effects of fire incidents and possible consequent health and safety hazards has been undertaken focused on the application of mine fire simulation software packages for contaminate tracing and fire modelling in coal and metalliferous mines. This paper examines aspects of introduction of inert gases to underground workings to aid recovery of a mine following a fire. Broad conclusions from work undertaken at individual Australian coal mines are discussed as examples. The effort is built around the introduction of the fire simulation computer program æVentgraphÆ to the Australian mining industry and the consequent modelling of fire scenarios in selected different mine layouts. Case studies have been developed to examine usage of inertisation units and particularly application of the GAG jet engine unit. One example has focused on selection of the best surface portal location for placement of the GAG for most efficient suppression of a fire. A second has examined a situation with significant seam gas being emitted on the face. This has shown that under certain face dip angles stopping the mine surface fan to reduce dilution of GAG exhaust gases will cause reversal of face air and consequent mine explosion as gas laden air is drawn across a fire. A third examines inertisation and dilution issues in mains headings. mains headings present a complex ventilation network with often numerous parallel headings, hundreds of cut-throughs and a variety of ventilation control devices. In such a complex system (with additional interference from a fire), maintaining control of the movement of inert gas is more difficult than elsewhere in the mine. Some illustrations of this issue are given.

Jan 1, 2005

By G Tsatouhas, R Newell, K Y. Wong

A sulfide ion selective electrode was used to control sulfidiser addition in the flotation testing of a synthetic and a naturally occurring ore containing malachite in order to compare the behaviour of sodium sulfide and calcium polysulfide. Both slug and controlled potential sulfidisation methods of addition were used. Under defined optimum CPS conditions, calcium polysulfide was a more effective sulfidising agent than sodium sulfide on the basis of both capital and operating costs. Surface and solution studies were used to compare the mechanism of each sulfidiser. For calcium polysulfide, XPS showed that polysulfide ions are adsorbed, whereas for sodium sulfide it is the hydrosulfide ions that are adsorbed on the mineral surface. For calcium polysulfide, the CuSx layer was believed to form on the malachite surface, which promoted the flotation of the malachite, by xanthate. Studies of surface morphology of the sulfidised malachite showed that a fairly uniform sulfidised layer is formed with both reagents. The use of sodium sulfide resulted in a thinner initial sulfidised layer compared to polysulfide at equivalent initial sulfur concentration.

Jan 1, 2005

By F Clark, J T. Carswell

Ore definition for final stope planning is often a challenging prospect in underground (UG) gold mines which exhibit high geological and grade variability. Unlike the grade control (GC) scenario in an open pit (OP), the ability for the mining geologist to plan a sampling campaign which effectively characterises the underlying mineralisation is fraught with difficulty. UG sampling patterns are strongly clustered and typically not dense enough to characterise the spatial and statistical properties. Very commonly, sample volumes are not large enough to provide a reliable grade estimate of the surrounding rock. These factors critically affect our ability to accurately map out ore positions and estimate metal quantities.At Sunrise Dam, traditional UG sampling and modelling techniques have proven to be an unreliable strategy for successful stope planning and extraction. The problem was first observed during the final cut-back in the open pit for which the mineral resource model was constructed from UG diamond drilling. Open Pit grade control reconciliations were strongly positive for both tonnage and grade compared to the resource model. Underground workings missed significant quantities of ore which was laterally defined by open pit reverse circulation (RC) GC drilling. Upon examination it was realised that the cause of the problem was one of inadequate sample density and sample support, the implications of which potentially affected the entire UG mine.As part of a broader study into underground grade control procedures, detailed reconciliation of initial stope production from the GQ domain also pointed to inadequate sampling as a major constraint to effective grade control and reserve conversion.To overcome this deficiency, dense 115 mm wet RC grade control drilling and conditional simulation modelling has been successfully implemented with the intent to replicate the grade control process in the open pit. The increase in sample density and sample volume has proven to be a very effective tool for mapping out highly complex mineralisation. A marked improvement in stope definition, reserve conversion and Mine to Mill reconciliations has been demonstrated on the back of an innovative approach to UG grade control.CITATION:Clark, F and Carswell, J T, 2014. Using reverse circulation drilling to improve sampling in a complex underground gold operation – an innovative approach to underground grade control at the Sunrise Dam Mine, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014 , pp 143–152 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

Average annual growth in consumption of primary energy in Australia over the past 10 years has been 5·5 per cent compared to a world average of 4·1 per cent.Over the next 10 years growth rate is expected to increase to 6 per cent per annum due largely to the rapid development in the mineral processing industry.By the end of the 19705 natural gas is expected to supply more than 9 per cent of Australia's primary energy market. Coal will supply 40 per cent and petroleum products 47 per cent. Nuclear energy will make its appearance but will make only a small contribution in the period.Australia has adequate reserves of natural gas and coal to supply its needs in the 1970s and beyond. However the newly developed reserves of crude oil, while supplying 60-70 per cent of requirements in the initialyears, will need regular and sizable additions if they are to keep pace with the expanding consumption. For Australia to become self sufficient in the period 1970-1990 it is estimated that new discoveries will need to approximate ten times the volume of recoverable reserves found in Australia to date.

Jan 1, 1971

By Merry N, Cocks T

The mineral exploration industry is increasingly aware of the importance of the relationship between mineralogical data and geochemical assay results. However, until recently, the cost and time constraints of most techniques for analysing alteration mineralogy have precluded detailed alteration studies. These impediments have been reduced by the development of the Portable Infrared Mineral Analyser (PIMA), a field portable infrared spectrometer that allows rapid (in field) and cost effective analysis of alteration minerals including subtle variations in mineral crystallinity and Composition.

Jan 1, 1995

In order to fully understand why Amax Coal puts such extreme emphasis on the drilling and blasting programs at each of our mines, we must review the past. This paper will discuss the drilling and blasting techniques we used in the 1970s and their evolution to current practices. As time progressed, major changes influenced the surface mining of coal through new more restrictive governmental controls and local communities organising into groups with two goals in mind, one to shut down the mines and the second to try and get rich by making false and unjust damage suits against the mines. In virtually all of our midwest surface operations we have at one time or presently are facing litigation that has reached into the millions of dollars. Amax Coal has worked in co-operation with the United States Bureau of Mines in the areas of blast vibration, shot design, highwall safety, blast casting studies and many more. Today we are continuing to work with Dr David Siskind and his expert staff seeking answers to old and new problems addressing the blasting of overburden and parting seams.

Jan 1, 1995

By Russell F. M

Following the accident in the Peterson section of Mufulira mine in September, 1970, a method had to be found of extracting up to 300 000 tonnes of ore per month from this area without inducing caving. Sandfill mining methods were chosen, necessitating a plant capable of producing both cemented and uncemented fill on a large scale. The paper covers the design and construction of this sandplant which is thought to be unique for its size, as it incorporates three 3 000 tonne capacity settled storage silos, a 500 tonne capacity cement silo, mixing tanks and a control room situated underground. The plant is designed to handle an aver- age of 440 tonnes per hour with a maximum of 660 tonnes per hour for limited periods, delivering either uncemented fill or cemented fill in proportions varying from 1:6 to 1:30. The instrumentation and equipment necessary to give one man operation of the plant is described and the fill mining methods now in use at Mufulira are briefly outlined.

Jan 1, 1973

By Dinuzzo P, Wychie J, Desoe C

The Selwyn Gold-Copper Mine is located 150 km southeast of Mount Isa within Proterozoic units of the Mount Isa inlier (Figure 1). Mineralization in the mine area is associated with strongly sheared ironstones and iron rich schists at the base of the mid- Proterozoic Staveley Formation. The ironstone horizons outcrop as a series of dominant ridges over a 10 km strike. Economic gold-copper mineralization has been defined in 4 separate zones within a 3.5 km length of the outcropping ridges. A current combined geological resource for the deposits is 5.3 million tonnes of 5.0 g/t Au and 2.02 Cu. Weathering of the deposits has resulted in a pronounced vertical zonation of mineralogy, especially copper, within the ore zones. This has produced 3 separate ore types which require different treatment techniques. The categorization is based on copper content and zones are termed leached (surface), oxide and sulfide. Ore removed from the pits will be mainly leached and oxidized with minor sulfide near the pits final depths, while the underground ore will be from the sulfide zone with minor oxide in some areas.

Jan 1, 1989

It is generally known that Charters Towers was discovered by Mosman, Clarke and Fraser in 1871. However, the time was ripe, and these three were barely in front of others. There is one account that prospectors from Ravenswood visited the area months before but decided it was too far from water, and that one of them had told Mosman and party of the find. There is another account that Joe Larkins found the discoverers before they had registered any ground - this may explain Mosman's quick departure for Ravenswood.When the news spread, the rush was rapid, and there was soon a sizeable population: probably too many, as within twelve months the infant settlement was under considerable stress. First, the presiding Gold Commissioners had adopted "unusual and arbitary" interpretations of the Regulations, and many of the miners were aggrieved; Charters, the senior Commissioner, was accused of favouring moneyed interests, and of retiring ill whenever a brawl or confrontation occured. As a result, the law of the field soon became "the survival of the strong". Second, the settlers were, divided on where the main town should be: Millchester, near the water, or Charters Towers near the mines. Third, the discovery of gold at the Millchester Deep Lead in August, 1872 was followed by highly exaggerated accoants in_' the southern papers, apparently fabricated by local business speculators. The resulting rush resulted in hundreds of unlucky prospectors having to return or seek other fields. In that period two men were killed in squabbles over ground. To make matters worse, by October 1872 a drought had set in, water cost three pence a bucket, fodder was scarce, cartage expensive, and the price of crushing ore rose to thirty shillings per ton.

Jan 1, 1986

By A Sinuhaji, H Kalangi, T B. Setyoko

Ore fragmentation at the DOZ block cave mine is highly variable, both as a function of rock type and column height of draw. Initially, the mine was constructed and equipped with limited capability to handle drawpoint oversize material. Significant issues with drawpoint availability and achieving overall mine production targets resulted. A suite of secondary sizing tools was added to the mine equipment fleet over a one-year time frame. Although significant oversize continues to be experienced, use of the correct secondary breakage tool for each particular oversize or hang-up occurrence has resulted in increased drawpoint availability, production rate, draw compliance, and operator safety. Currently, a range of secondary breakage techniques is being utilised to size material for delivery to the primary crusher. Run-of-mine material (3) is directly mucked to ore passes fitted with grizzlys that have one-metre square openings. Ore containing small boulders (>1 m3, 3) is loader-trammed to ore passes fitted with rockbreakers. Medium-sized boulders (>2 m3) accessible from the drawpoint are drilled with Sandvik Tamrock Commando drills. Boulders hung-up within the drawbell are drilled and charged with a Sandvik Tamrock Secondary Breakage Unit. Compacted, fine-grained muck is blasted utilising 55 mm cartridge powder concussion bombs.

Jan 1, 2005

By Ruston R

When coal mining first commenced in Australia, the principle objective was low cost production with development directed toward recovery of 'easy' coal. Future expans- ion of these early mines into major under- ground operations was neither envisaged nor planned. As the demand for coal grew, these mines were expanded to increase output. however, the absence of initial ventilation planning brought about ad hoc systems wh;ch required continual repair and upgrading. These systems proved satisfactory in the short term because the majority of undergrouni coal mining operations were carried out at relatively shallow depths where gas emission rates were low. By comparison, coal is now being won at depths exceeding 500 metres with a corresponding increase in gas flow from the working seams and adjacent strata. The following paper addresses, firstly, the planning and institution of a ventilation system in a mine where previous inefficiencies were many, and secondly, the value of pre- planning a mine ventilation system in the early stages of mine development, and the need to continually review and upgrade the plan to account for unforeseen ^hanges.

Jan 1, 1983

A review is given of progress made to- wards the development of personal gravimetric dust sampling for risk assessment on South African gold mines. The present strategy is critically examined on the basis of principles for assessing health hazard from dust exposure. Reasons are advanced for replacing the konimeter with a gravimetric system based on full shift personal sampling. Constraints imposed by local characteristics of gold mines are used to illustrate the difficulty in finding suitable instrumentation for measuring personal exposure to respirable silica.

Jan 1, 1988

By Leahy G. J, Moxon N. T, Nicol S. K

Experimental work is described in which extremely dilute aurocyanide liquors are treated with novel surface-active complexing agents to produce a hydrophobic aurocyanide species. Subsequent aeration of these liquors causes accumulation of such species at the air-water interface and the aurocyanide complex is transferred to a froth concentrate. A detailed performance assessment of this process is made and this knowledge used in the design of a pilot plant facility. Early results indicate the feasibility of the selective recovery of aurocyanide ions from reclaimed residue dam water (approximately 0.2ppm Au) with upgrade ratios of the order 180:1. A further study was made applying ion flotation to the recovery of gold from a carbon-in-pulp (CIL) feed liquor (approximately 1.0ppm Au). The probable economics of this process compared to conventional CIL processing is also described. Successful development of countercurrent ion flotation for concentrating solids-free gold solutions may offer a lower cost alternative to existing gold ore processing technologies, or in more secondary applications such as concentrating dilute gold solutions or heap leach runoff. The technology may also have more generalised applications to other heavy metal process- Ing.

Jan 1, 1991

By Nidagal V

This paper discusses the dewatering strategy adopted and the considerations and procedures required to incorporate a dewaterinq scheme into the Mt Whaleback mining operation. It concludes that in pit pre-dewaterinq has successfully allowed mining to progress below the standing water level with the minimum of disruption or radical change to the mining method. It is recognised however, that dewatering is not a static activity and there is a requirement for ongoing investigations and development. Pre-dewatering commenced in October, 1984. Purpose designed pumping trailers have been employed to minimise the loss of pump availability resulting from the frequent. need to remove and reinstall pumps when close vicinity blasts occur. To July, 1986, some 0.5 Mm' of groundwater had been pumped from the unconfined orebody aquifer. Mining has progressed to some 20 m below the standing water level without. any undue water associated problems. Ultimately, it is ,cheduled to extend some 300 in below the original water level in the West Pit. With the development of an increasing area of the mine below the standing water level, the influence of seasonal high intensity rainfall events, which had previously caused little concern, now need to be addressed. Pumping equipment has been designed to evacuate storm water at a rate consistent with mine production Considerations.

Jan 1, 1986

The blasting process involves a complex interaction of a delayed sequence of moving sources of seismic energy which produce nonlinear behaviour near the blast holes. A deterministic description of this nonlinear behaviour represents a formidable problem. The modelling of blast vibrations remote from the blast source may use some of the primary features of the blast design such as charge type, charge weight and initiation sequence. Such modelling of blast vibrations usually assumes linear behaviour remote from the blast holes. Site specific charge weight scaling laws may be used to predict the blast vibration levels with relatively poor accuracy. An important ingredient which is missing from charge weight scaling laws is the seismic source wavelet emanating from each blast hole. The present paper considers some approaches which may be used to determine a suitable source wavelet. The wavelets are suitable for use in the region where linearity may be assumed. In that region, it is possible to model the attenuation and scattering of the seismic wave as it propagates from the blast source to the measurement location.

Jan 1, 1990

By Collins DN, Hollick CT

Conventional processing of heavy mineral deposits containing radioactive rare earth minerals such as monazite and xenotime may cause industrial hygiene problems through atmospheric dust and contamination of product concentrates. An alternative procedure has been developed in which such minerals are removed from bulk heavy mineral concentrates by flotation with little loss of other economic minerals. With fine ores, recoveries of over 95% have been achieved and with coarse ores over 80%,in both cases at high grade. Several flotation regimes have proven effective. The potential for generation of radioactive dust or product contamination is subsequent processing -is correspondingly reduced.

Jan 1, 1990

By Callinan AN

Broken Hill Proprietary Company Limited have recently commissioned a 14 Megawatt power station adjacent to its underground coal mining operation at Appin NSW. The power station is fuelled by methane gas extracted from the coal seams 500 metres below the surface. The methane is compressed and cooled prior to its injection into the combustor of a single shaft gas turbine. The turbine is coupled through a reduction gearbox to an alternator. There is sufficient power generated to cover colliery load, with any excess being exported to Prospect County Council, which is the supply authority for the south western region of Sydney.

Jan 1, 1987