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By L Torckler, J Hobbins

Favona is a blind low-sulfidation epithermal vein deposit in the Waihi Vein System approximately two kilometres east of the world class Martha Hill deposit that has produced nearly 6.8 M oz Au to date. The Favona epithermal system has surface expression in variously altered and mineralised hydrothermal eruption breccias forming a series of low hills that are windows through post mineral dacites and ignimbrites. The tip line of the Favona vein is about 50 û 100 m below surface with a steeply east dipping principal vein structure carrying numerous hanging wall splays in the upper flatter section and thickening down dip where the vein steepens. Host rocks comprise feldspar phyric andesite flows with minor pyroclastics. Although Favona has a strike length in excess of 1000 m and vein widths up to 25 m over a vertical range in excess of 400 m it was only recently discovered after nearly thirty years of exploration by various companies involved in the Martha Hill joint venture that operates the Martha Mine. Since discovery in 2001 a feasibility study based on 27.5 km of diamond drilling in 83 holes has been completed reporting a reserve of 1 Mt @ 10 g/t Au against a resource of 1.8 Mt @ 10.3 g/t Au. Exploration is continuing with a further 20.5km of diamond drilling completed to date on nearby prospects.

Jan 1, 2004

By S Wainio, P J. Beckett, T Miller

Lichens are a symbiosis of fungi and algae. Air borne elements and gases are absorbed very efficiently over the entire surface of the lichen, because they have no protective structures such as a waxy cuticle or stomata. A survey in 1977 (one year before the Sudbury Regreening program began), indicated that several Cladonia spp had invaded the soil in Sudbury’s open birch woodlands. Pollution sensitive species such as Cladonia rangiferina and C. mitis occurred 20–25 km from the smelters. It was anticipated that the improvements in air quality and reclamation efforts would allow a natural invasion of pollution sensitive species into what once was a lichen desert that surrounded the smelters. The purpose of this project was to study the invasion of terricolous (soil-inhabiting) communities of lichens and mosses on reclaimed land in the Sudbury region 45 years after commencement of the Sudbury Regreening Program.

Aug 2, 2023

Madison Enterprises Corp. and Matu Mining are currently ex- ploring the Mt. Kare property in Papua New Guinea. The Mt. Kare gold prospect has had a short but very active history, since the first discovery of gold in the area in 1986 the property has sccn: a 3 year gold rush during which 10,000 alluvial miners re

Jan 1, 1997

It is hypothesised that increasing the number of loading passes will produce a reduced range of truck payload outcomes compared with four-pass loading. The paper provides analysis to support this hypothesis. It is shown that, hypothetically, loading trucks with five or more passes will result in reduced tendency for overloading and reduced confidence interval for truck payloads that increase the confidence level of containing high end payloads within safe and commercially acceptable limits. Furthermore, increased number of passes provides for more precise bucket load spotting and so improves distribution of payloads within truck bodies. Truck-loading issues examined by the paper include: Improvement in life of driveline components and tyres. Generally tyre costs are relatively moderate; but tyres tend to become an increasingly sensitive performance/cost component as truck scale increases; Reduction of site severity fects flowing on to suspensions, truck frames and structural components generally with potential for reduced long-term repair costs; Less physical body damage due to smaller load increments; Reduced risk of non-compliance with payload limitations for safe braking standards; Increase in loading cycle times tend to increase with scale of loading machinery within the limits of a specific type of equipment (ie rope shovels or hydraulic shovels). Production increase with increased bucket capacity is, to a degree, offset by slower loading cycle times. This is particularly pronounced with front-end loaders but tends to be less noticeable with hydraulic excavators/shovels and electric rope shovels. Decrease in loading time, as a proportion of total truck-cycle time as open pits deepen and dump reaches increase. The production and cost benefits of four-pass loading tend to diminish as truck cycle times increase. The paper also discusses the implications for loading-equipment philosophy to satisfy the future needs of the industry. Cost benefits from upscaling tend to diminish as truck scale increases, so increasing management diligence and close monitoring are required to ensure that expected outcomes are realised. These truck-loading issues have been researched to assess the benefits positive or negative) of four-pass loading in practical scenarios. An attempt is made to determine whether four-pass loading is a æmust-haveÆ or merely a æmythÆ.

Jan 1, 2003

The Barra Mine was the most significant mine of Australia's earliest mining era, which took place in South Australia between 1841 and 1851, the decade prior to discovery of gold in eastern Australia. Between 1845 and 1860, Barra was the largest metalliferous mine in Australia and employed up to 1000 men and boys, most of them Cornish.""Today the site is also important in a physical and archaeological sense as it contains extensive remains of mining and processing operations of the period 1850 - 70. Most significant are three cnginchouses which housed Cornish beam engines.

Jan 1, 1993

Recent analysis of backfilling material has shown that a finer size distribution is preferable for stope filling. In order to increase crusher throughput and pit productivity, a reassessment of the quarrying operation was conducted. Part of that reassessment was a review of blasting practice. Six means of reducing the average muckpile fragment size were examined. Different blast initiation and charging options were compared, and patterns using smaller hole sizes were designed, analysed with the JKMRC 3x3o software, then drilled and fired. The ground vibration and face movement was recorded and compared. To determine whether the Kuz-Ram model could be used in an economic analysis of the quarry operation, the fragmentation distribution of the small diameter hole blasts was determined. Photographs of the muckpiles were taken and digitised. However subsequent analysis indicated that a satisfactorily large photo sample was only obtained from the smallest diameter hole blast. The Kuz-Ram fragmentation model prediction was found to be within the confidence limits of those results. An engineering and cost comparison between the blasts was made.

Jan 1, 1995

The aim of this paper is to broadly review the purposes of valuations and the methods used to calculate them. Examples are provided by coal and alluvial gold properties. Important factors are consistency, how to deal with uncertainty, and the selection of discount rates. The purposes of valuation are seen as: 1.  valuations for sale; within this category are sales to third parties, sales between partners, and vendor valuations for prospectuses; 2.  to provide bankable estimates for financing; and 3. to provide values for local body rating. The methods used depend on the purpose of the valuation and the amount of information to hand.

Jan 1, 1988

By P Warner

Mines are often located in remote areas that are not well served by æstiffÆ power grids. Radial transmission networks, high lightning incidence (eg in South Africa the Witwatersrand experiences seven to ten strikes/km2 per year), low short circuit strengths and diesel generation are not uncommon. All these factors result in the electric power supply to many mines being unusually prone to dips and disturbances. æLegacyÆ winder drives û cyclo converters and dc drives û convert power directly from the supply to the motor, with no intermediate energy storage element. Further, they rely on the supply network for commutation and are therefore sensitive to supply voltage disturbances. There is a high probability that a dc or cyclo mine winder will trip during a supply disturbance, often resulting in lost production time and call-outs for technical staff to reset or even repair equipment. In contrast, a voltage source inverter (VSI) ac drive stores a large quantity of energy (in the dc link capacitors) and is fully self-commutating. Hence, this topology is inherently more immune to supply voltage disturbances. Indeed, vendors of ac VSI mine winders make general statements about the superior performance of their drives during supply disturbances. However, the advantages have apparently not been previously quantified. This paper compares different winder drive topologies and their sensitivity to supply disturbances, considers categories of supply disturbances and quantifies the cost of the effects on the different drive types.

Jan 1, 2005

By Lyman GJ, Davis JJ

Models which have been presented in the literature consider only selected aspects of dense medium cyclone operation, are empirical in nature and generally relate only to severely limited ranges of operating parameters. This paper reports progress towards development of a more comprehensive and robust model. The data base consists of partitioning parameters developed using density tracers and conventional coal sampling and analysis techniques, together with recordings of parameters such as cyclone dimensions, feed pressure, medium size distribution and product media densities.. These data were drawn from 15 Australian coal preparation plants. To elucidate the effects of important operating parameters on medium behaviour and on the partitioning of large particles a series of pilot scale tests was also conducted. The present model consists of eight sub-models which relate to particular aspects of dense medium cyclone operation such as medium flowrates and densities, or size- by-size separation densities and Eps. The model structure follows a logical progression which clearly demonstrates the importance of understanding medium behaviour before attempting to predict partitioning performance. The model also attempts to define the conditions under which yield losses due to unstable "surging" discharge may occur.

Jan 1, 1987

By Blackham M

West Wallsend No. 2 Colliery is a new mine that is presently being developed in the New- castle Coalfield by J. & A. Brown & Abermain Seaham Collieries Ltd., a subsidiary of Coal & Allied Industries Ltd. It is situated near Barnsley and is some 15 miles by rail from the port of Newcastle. The mine will produce coal from both Bore- hole and Young Wallsend seams. The Borehole seam has a working seam thickness varying from 7 ft to 5 ft while the Young Wallsend seam presents a choice of two distinct working thick- nesses, i.e. 5 ft. or 8 ft, the upper 3 ft containing much high ash material. The inter- seam interval varies from 10 ft on the western edge of the area to more than 70 ft in the central portion. The Borehole seam lies at a depth varying from 550 ft to 750 ft and the overlying surface terrain is gently undulating bushland with limited surface development.

Jan 1, 1972

In an industry that is data-hungry and increasingly international in its outlook, the role of the New Zealand Government in facilitating exploration and mining activity here presents unique challenges. All things being equal, the Regime itself should result in æefficient outcomesÆ, however central to this rational economic tenet are the assumptions that the regime is in keeping with the times, other legislation works in tandem with it, and that those who administer the regime have the knowledge and experience to apply the rules wisely. Following the Crown Minerals review in late 2003, a shift in emphasis from Crown Minerals æmanaging the ActÆ towards proactively æmanaging the mineral estateÆ for greater benefit for all New Zealanders means that these assumptions are being increasingly challenged and addressed through a variety of initiatives. These include improved access to relevant data sets, minimisation of red tape and compliance costs, increasing emphasis on permit holder compliance with work programme obligations, changes to the Minerals Programme and regulations, closer collaboration with and representation to other government departments and councils, and additional recruitment of industry-experienced staff. This presentation will highlight aspects of these initiatives, and examine how they will collectively contribute to facilitating future exploration and mining activity in New Zealand.

Jan 1, 2004

In May 1977 a new dam was commissioned for disposal of 600,000 metric tonnes/year of tailings. Design basis, costs and construction problems are described. Problems arose, assoc- iated with lack of experience in building such a dam "from scratch". Solutions are described land costs given.

Jan 1, 1978

By Carr SD

The Omineca Belt of the Canadian Cordillera straddles the western boundary of the North American paleocontinental margin and accreted oceanic and island arc terranes. Crustal thickening of the orogenic belt was initiated in the Jurassic and culminated in latest Cretaceous and Paleocene times.Thin-skinned shortening of the Rocky Mountain Foreland Thrust and Fold Belt was balanced by basement-involved crustal imbrication within the Omineca (hinterland) Belt. Middle and upper crustal rocks of the hinterland (Selkirk allochthon) were thrust eastward and ramped onto basement of the North American continental margin. By latest Paleocene the southern Omineca Belt formed an elevated crustal welt that was at least 60 km thick.Within less than 3 Ma of the culmination of crustal thickening the belt was rapidly uplifted and tectonically denuded. The southern Omineca Belt was extended by as much as 80% as upper crustal rocks were displaced on moderate to low angle normal sense shear zones and brittle normal faults. This oro-genic collapse is interpreted to be a gravitational response to crustal thickening and thermal soft-ening, facilitated by reduction in plate-boundary-induced far field stresses.

Jan 1, 1990

By T A. Carter

In 2010 Agnew Gold Mine (AGM) struggled to produce the required tonnages from its stopes. The longhole rises used to create void in stopes were unreliable and often failed to gain the designed rise height. The number of firings per stope was having an adverse impact on the ground conditions at the stope brows, impeding stope productivity.Through practical experimentation with longhole drill rigs, box hole rigs and development drill rigs as well as trialling new methods in conjunction with reviewing drill hole data, drill hole accuracy was observed to be an issue on-site. Innovative dragging methods such as the reverse drag, combined with a slope instead of a vertical face on the rear of stopes, have improved dragging and a reduction of firings per stope, enabling larger production blasts.The methods trialled and subsequently implemented at AGM have facilitated the mine achieving budgeted targets for six consecutive quarters. This paper documents the use of these methods in a key lode of AGM’s operations to improve drill and blast practices in order to achieve production targets.CITATION:Carter, T A, 2014. Improving production drilling and blasting in the Kim South orebody at Agnew Gold Mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 251–258 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

ATTENTION has recently been directed to the subject of dust production and methods of allaying same in the Broken Hill mines, so that the time would seem opportune for the local branch of the Institute to discuss certain features of an important phase of the health question in connection with underground work. Tests conducted in the Broken Hill South mine and at other mines at Broken Hill have shown that the ordinary operatioils of mining, such as boring, blasting, and shovelling, may be accompanied by the production of considerable dust unless water is judiciously used.In South Africa·dust particles under 5 microns size are regarded as dangerous, becailse they are so small as to be invisible to the naked eye, and wm esc'ape the protections set up by nature in the nose and throat, and thus may be inhaled in large quantity. A micron is 1 25000th part of an inch. This paper contains an account of the work done on the Broken Hill South mine chiefly, though some tests were done on other local mines.An acknowledgment is due to Mr. T. A. Reid, of the Broken Hill South mine, who conducted some of the tests herein mentioned, and under whose supervision most dust counts were made. Numerous dust samples have been taken by means of thekonimeter, an instrument designed by Dr. Kotze, the Government mining engineer of the Union of South Africa, and fully described...

Jan 1, 1921

By Eisele TC

Horizontal perforated-plate baffles were shown to improve the cleaning efficiency of a flotation column when processing coal from two sources. The baffles consisted of flat plates with holes large enough to avoid plugging problems, and they improved the washing efficiency by making the flow patterns in the column closely approach plug flow. Tests with varying amounts of baffle open area showed that the optimum was between 30 and 40 per cent open area, which effectively prevented backmixing without seriously reducing capacity. The baffled column had previously been tested under ideal conditions with good results (87 per cent pyrite rejection at 85 per cent combustiles recovery), and so the tests reported here were intentionally run with difficult-to-float coals to determine the benefits of baffling under adverse conditions. For an original coal feed containing 38 per cent ash and 3.23 per cent total sulphur, the baffled column could recover 84 per cent of the combustibles while rejecting 84 per cent of the ash and approximately 54 per cent of the pyritic sulphur. Without baffles, the column recovered 88 per cent of the combustibles while rejecting only 76 per cent of the ash and 45 per cent of the pyritic sulphur. Subsequent tests with a dye tracer showed that the baffles reduced entrainment by approximately a factor of five, while the recovery was reduced by only a few per cent. Overall, the loss of capacity due to the baffles was more than offset by the improvement in product quality.

Jan 1, 1993

By Dorricott M. G

Ballarat Goldfields NL is developing an exploration decline at Ballarat East using a Mitsui Miike S-125 roadheader. To-date, 530 in of advance has been achieved at an average rate of 16.1 m/week. Roadheader availability has averaged 94.3 per cent, and pick consumption has averaged 0.016 per m. Ground support has involved pattern rockbolting with split sets, 100 mm thick fibre reinforced shotcrete, and steel sets as required. The slower than expected advance rate has mainly been due to difficult ground conditions. It is expected that a further 970 in of decline will be mechanically excavated before a drill and blast system becomes more economical.

Jan 1, 1995

By Seedsman R. W

Good roads are essential in moving men and materials to and from the underground workplace. Coffey Partners International Pty Ltd (Coffey) has recently completed a underground coal industry funded project on underground mine road construction and maintenance. This paper discusses practical approaches to construction and maintenance of underground mine roads using transferrable civil technologies and innovative techniques. Mine pavements are generally low-cost (relative to civil roads), constructed to varying standards using locally available materials to best meet the mobility needs of the mine. Performance of pavements is thus largely dependent on the environmental conditions, quality of the available road making materials, maintenance policies and available resources. The paper will detail `what causes bad roads?' in various underground environments, available management strategies, construction and water control techniques, road maintenance and vehicle considerations.

Jan 1, 1995

The design and operating characteristics of the hydraulic cyclone elutriator were described in detail by Kelsall and McAdam (1963), and the method of operation of the commercially available version, the Cyclosizer, is described in the manufacturer's pamphlet (Anon). Complete details of the operating procedure are given in the relevant operating manual (Anon, 1964).The cyclones which form the basis of the Cyclosizer (Fig. 1) under normal operating conditions produce typical cut sizes of 44, 33, 23, 15, and 10 µm for cyclones one to five respectively for material with a specific gravity of 2·7. At the end of the selected elutriation period each sized fraction is discharged and collected for subsequent assay or analysis but all material rejected by the fifth cyclone (e.g. minus 10 \lm quartz) normally passes to waste. When this material is needed for separate study, although its amount and average analyses can be calculated by difference, it may be necessary to collect more than 250 I. of very dilute suspension, flocculate the solids, allow to settle, and decant off the supernatant liquid.This procedure is cumbersome and inconvenient and the simple technique to be described may offer some advantages. The temperature of the water fed to the Cyclosizer is maintained at a constant value for added reproducibility.PROCEDUREThe present overall treatment of the subsieve material (minus 37 \lm) fed to the Cyclosizer incorporated several refinements compared with normal operation and these may be best illustrated by anactual example. Material to be cyclosized (25 to 100 g depending on size distributIOn and specific gravity) is completely dispersed in water at 23 QC by vigorous stirrmg, using suitable dispersants if necessary, in a...

Jan 1, 1974

By Miller RJ, Eager DT, Lama RD

For safe and efficient mining operations, it is essential that environment and equipment status be monitored. A system that gives quick access to status at any given time, and also permits quick analysis of their history, is required. Such a computer based monitoring system has been installed at West Cliff Colliery.The system is based on 2 super mini computers. Three major sub-systems monitor conditions in the longwall operations, environmental conditions in the intake and return roadways, status of the underground and surface installations, and mining and transport equipment.

Jan 1, 1985