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The importance of the accurate determination and interpretation of the bulk density and porosity of a given iron ore deposit is very often disregarded or neglected. Large amounts of time and money are spent on delineating and testing orebodies, and yet one of the most important factors in resource evaluation is sometimes estimated or, at best, determined from existing data from similar deposits. The Thabazimbi and Sishen South iron ore deposits are two well-known economical occurrences of high-grade iron ore in South Africa. Both these deposits formed as secondary enrichment of banded iron formation lithologies. Ongoing density studies on both these deposits are underway and results thus far proved very effective and necessary. Small-scale methods are used to determine average values for different ore types on both deposits. These values are used in resource estimation and geophysical interpretation.

Jan 1, 2007

By T D. H McGrath, J P. Vaughan, J Heath, J J. Eksteen

A reliable laboratory method to characterise the response of free gold particles when subjected to flash flotation conditions has been developed by AMIRA P420 researchers at Curtin University. This test has been applied to assess the flotation recovery of gravity recoverable gold from free milling ores as well as synthetic ores featuring either a gravity concentrate or gold powder. Trends in free gold flotation kinetics as well as size and milling effects were identified for gold recovery, based on the different gold types, reagent dosage and residence time.CITATION:McGrath, T D H, Eksteen, J J, Vaughan, J P and Heath, J, 2013. Laboratory flash flotation trends for a variety of gold particles, in Proceedings World Gold 2013 , pp 357-366 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Bothe C

Froth flotation processes use different surface properties of the minerals to be sorted. In an aqueous environment the hydrophobic mineral attaches selectively to air bubbles and is lifted to the surface of a separation vessel, while the tailings settle towards its bottom. Besides the surface properties, the hydrodynamic conditions play an important role. With respect to the hydrodynamics the flotation process can be divided, for simplicity, in two sub-processes. The attachment of hydrophobic particles to air bubbles, the so-called mineralisation, demands a large number of collisions and therefore high turbulences. The phase separation however needs a deterministic movement of both the particle-bubbles-aggregates and the tailings particles and therefore a quiescent flow field. The optimisation of the overall process requires a separation of both sub-processes, especially when fine particles have to be sorted. In conventional mechanically agitated flotation cells both sub-processes take place in the same turbulent volume. For this reason they suffer from a decreasing selectivity with decreasing particle size. In flotation columns the mineralisation of air bubbles and the phase separation are performed in a quiescent environment. This results in high concentrate grades and at the same time in a very slow attachment kinetics, which must, especially for fine particles, be counterbalanced by a long residence time of the slurry.

Jan 1, 1993

In an area north of Mowit Ica chip sampling of limonitic outcrops on a regional scale led to the investigation of a number of areas considered to be geochemically anomalous for copper and zinc. These areas were closely gridded,end where geochemical results were favourable, they were subsequently drilled or ro¦titeaned Che results indicated that for copper Lne anomalies were mainly associated wiL_ ironstone formed in areas of faulting. is suggested that copper is able to move considerable distances by ground water movement and is likely to be fixed under conditions of low pH. The movement of zinc is more difficult to explain but it appears to have an affinity for iron and is only deposited in areas having a high pH (i.e. doioiirific scdimet=Cs).

Jan 1, 1973

Since the 1950's drilling has been rapidly mechanised. First from hand held drills with air legs to pneumatic jumbos, then to more effective hydraulic jumbos. Development of underground drilling equipment naturally could not have stopped here. Hydraulic drilling saw an improvement in drilling capacity and efficiency after the introduction of second generation drifters in the early 1980's. Also in the early 1980's a few equipment suppliers started to study how to improve the efficiency in operating the rigs. The first computerised rigs for tunnelling were delivered to work sites in mid 1980's. At the same time a few computerised longhole drills started drilling in mines.

Jan 1, 1988

By Woodcock J. T, Zhu T, Sparrow G. J

A lead-zinc-pyrite flotation middling was pressure oxidised to give residues containing iron hydroxy sulphates (a mixture of basic iron sulphate (BIS) and a hydrated iron sulphate (HIS)) and lead sulphate. Direct thiourea leaching of this residue gave over 90 per cent extraction of gold and silver, but thiourea consumption was high (56 kg/t) because of soluble iron(M) in the residue. Attempts were made to decrease the thiourea consumption by removing the water-soluble iron(M) or reducing it to iron(II). Water washing of the pressure oxidation residue removed most of the hydrated iron sulphate but little of the basic iron sulphate. Iron removal was only 12-20 per cent, depending on the number of washes, from one sample which was low in HIS, and 40-45 per cent in another which was high in HIS. Iron extraction was not appreciably increased by using dilute sulphuric acid (with or without additions of sodium sulphite), dilute phosphoric acid, or sodium chloride solution (150 g/L NaCI). Direct thiourea leaching of the water-washed residue gave over 90 per cent extraction of gold but only 49 per cent of silver, with a thiourea consumption of 27 kg/t. However, the application of a water wash followed by reduction of dissolved iron(III) with sodium sulphite in the presence of thiourea, and then thiourea leaching resulted in over 98 per cent extraction of gold and silver for a thiourea consumption of 26 kg/t.

Jan 1, 1991

By A Clarkson

Cannington Mine is an underground silver lead zinc operation located in north-west Queensland which has been in production since 1997. Ore is primarily moved through an underground material handling system comprised of a crusher, conveyor and hoisting shaft. The Fowler Shaft was constructed in 1997 using a strip and line method with the intent for it to provide a means to hoist ore from the loading station 600 m below surface. The shaft also serves as the route of key services including high voltage power, mine dewatering and fresh air. Despite the adherence to a mining exclusion zone, large-scale change in geotechnical conditions around the shaft were first observed in 2015. Ongoing ground movement around the shaft lead to cracking and delamination of the concrete liner. Shaft management required the on-site team to measure deformation rates and magnitudes, forecast change, manage rockfall risk and deforming pipework, and ultimately, hoisting skip clearance. Monitoring techniques to observe and measure deformation were required to evolve with the magnitude of movement. Some techniques leveraged off modern technology while some of the most useful techniques were based on logic and first principles. All shaft deformation management strategies relied on the co-operation and alignment between Cannington’s Infrastructure Maintenance, Survey and Geotechnical Departments.

Mar 29, 2023

By Dods G. H, Hewitt W. V

Ashton Mining Limited is currently one of the active companies undertaking gold exploration in Indonesia. Presently 7 Contract of Work areas are being explored for hard rock and alluvial gold. Hard rock exploration is focussed on the Tertiary volcanic arc terrains in which a variety of epithermal mineralisation styles have been identified. At the regional stage remote sensing techniques using Landsat, Spot and SLAR imagery where available, and photogeological studies are carried out in parallel with regional reconnaissance fieldwork programmes. These involve geological mapping and geochemical drainage sampling. Remote sensing techniques have proven useful in both the extrapolation of known geology and the identification of tectonically favourable settings as controls to mineralisation and volcanicity. The variety of mineralisation styles and settings is reflected in the highly variable geochemical signatures encountered. This has necessitated the refinement of sampling methods and sample preparation techniques for pan concentrate, stream sediment and soil samples in specific project areas. At the detailed prospect stage, mapping with particular attention to structural controls, wallrock alteration assemblages identified by petrog- raphy and XRD clay mineralogy, have proved useful in focussing drill targets. Drilling to date has utilised conventional diamond core drilling methods, the use of lightweight, man-portable "Winkie"-type rigs and hammer auger bedrock sampling systems. Geophysics methods successfully employed on various projects have included airborne magnetics and radiometrics, detailed ground magnetic surveys, VLF-EM and SIROTEM.

Jan 1, 1991

By Hale C. T, Carnie W. A

Rosebery mine has had over 100 years of mining activity. The reserve has remained static for the last eight years with an expected mine life of six years. A move to rectify this was made in 1994 with the birth of the Deep Exploration Project (DEP). $45 M was committed to drill 100 km of underground exploration diamond drilling and develop 5.5 kin of decline aiming to add 9.5 Mt to the reserves and minimise lead time for development of P and K lenses discovered in the early-1990s. In 1996 this aim was expanded with the objective to build the resource base to 20 Mt by June 2000 allowing the mill to operate at 1.0 Mtpa (0.9 Mt from underground). Preliminary results of the project to-date are outlined and exploration diamond drilling techniques and strategies are described.

Jan 1, 1997

One of the responsibilities of the Melbourne and Metropolitan Board of Works is to provide a sewerage system for the metropolis of Melbourne which now contains over 2.5 million people. In providing this sewerage system it was necessary for the Board to embark on a large tunnelling programme some 20 years ago. As a result of this extensive tunnel construction programme, tunnel boring machines and shaft sinking methods have been developed to cope with the soft ground and soft to medium rock found in the southern and eastern areas of Melbourne where the majority of the recent tunnelling has been carried out. While in the last few years radical changes in construction methods have not been made, development has continued and improvements have been made, which have enabled the Board to extend the limits of the ground conditions in which it can efficiently construct shafts and also tunnels with boring Machines.

Jan 1, 1976

By Bartosiewicz H

A method for the determination of the gas content of coal seams is presented which improves upon existing methods. The method makes use of a gravitational technique for measurement of the gas desorbed. The amount of lost gas is estimated by determining an empirical relationship relating the desorption of gas with time for each sample separately. This is to replace the assumption that desorp- tion follows a square root law with time. Laboratory investigations have been conducted which indicate that the square root desorption law does not hold good for carbon dioxide. Results of investigations on various factors influencing the technique are presented. It is shown that co-efficients of the empirical equation are dependent upon the elapsed time and the period of observation. Data about gas pressure measurements is presented and it is concluded that gas pressure can be approxi- mated to 0.6 times the pressure below a column of water equal to the depth of cover. This estimate is good enough for adsorption tests to evaluate desorption co-efficients. The technique for repressurisation of the sample,

Jan 1, 1982

Among countries afflicted with insLantaneous outbursts of coal and gas, Australia is noteworthy because of lesser disturbances of the seams and of the occurrence of CO2 in the seam gas from place to place. Research sLarted with the 1954 occurrences at Collinsville and Metropolitan Collieries leading to early publications reviewing the problem, describing occurrences and assessing variations in proneness factors in the two affected coal basins.The basic requirements for proneness include coals of high gas sorptive capacity, high ground stress, use of a mining method which provides higher stress concentrations and limits emission of seam gas, including high rates of advance. With CO2 in the seam gas proneness is greater.The mechanism is complex and not fully understood, but involves the coal, the roof, the floor, the gas, the mine opening, the ventilation, the kind of work and the rate of work. Geological disturbances such as faults and dykes increase proneness and tend to localise occurrences. On-occurrence of outbursts in some mines is difficult to explain.Outbursts are seen as a continuing threat to modem deep Australian mining of high rank coal.The simplest contributory factor to reduce is gassiness - despite the low permeability of outbursting coals - and present practices are showing promise. The greatest challenges for the future are partial degasification to below a known threshold figure and confirmation that this reduction is achieved and identification of anomalous geological structures ahead, the most likely locations for instantaneous outbursts to occur. The advances made to date give promise of a future with reducing experiences of uncontrolled instantaneous outbursts. For the Bulli seam particularly, working to achieve prediction and prevention is most urgent.

Jan 1, 1993

By Aziz NI

There are a number of methods available for the determination of the fracture toughness of rock. Some of the most recognised methods include the hollow pressured cylinder, the short-rod, the chevron - edge-notched round bar in bending and the disc-shaped compact specimen. Most of these tests are difficult and expensive to conduct. In this paper the simple Brazilian testing of discs for tensile strength has been used to determine their fracture toughness. Tests were conducted on six different rock types and the values of the fracture toughness obtained for each type are in close agreement with the results of the well recognised the chevron edged types. Details of the tests, and analytical validation of the technique, are presented

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 flexability to handle future variations in operating conditions. Thn -etom ..ill kn nvt,,ndnd to thn I-lalihn+ rJ,+f, rr , Into +hie -- -A +n the lei...,fieh .,lo+fnrmc A.,;- 1071

Jan 1, 1970

This study is to compare reinforcement of rebar and spiral bolts using laboratory pull-out test. For this purpose, the pull-out test was performed in laboratory for a curing period of 7- and 28-days. Based on the results of the laboratory pull-out test, the pull-out load of two support members rapidly increased with displacement until the breakpoint and then gently increased with displacement. The maximum pull-out load of spiral bolt was larger than that of rebar bolt. This implies that a spiral bolt is more stable than a rebar bolt for securing the stability of a ground or rock mass when a support was installed in a ground or rock mass under the same condition. In addition, the maximum external pressure of two support members increased with pull-out load and with displacement and the distribution of external pressure was commonly larger at the upper part than at the lower part of specimen. This indicates that the bond failure location by pull-out load should be mainly occurred at the surface portion of specimen. In conclusion, the reinforcing effect of a support depends on a curing period and a type of support member, and reinforcement of a spiral bolt is more effective than that of a rebar bolt.

Dec 6, 2010

By Shoobridge PH

Operating difficulties during 1977 with the Imperial Smelting Furnace operated by Sulphide Corporation Pty. Limited at their Cockle Creek zinc-lead smelter were found to be caused by premature softening of sinter in the upper shaft of the furnace. This soft- ening was shown to be a consequence of raw materials and operating policies which led to unusually high levels of both lead and silica in a sinter of low basicity. A programme of softening tests and micro-examination of a range of sinters established that premature softening occurred when lead and silica increased to the point where a lead-calcium silicate with a low lime content became the major continuous phase in the sinter. This information was used to define a range of compositions which kept the softening temperature acceptably high for furnace operations.

Jan 1, 1978

By J Ireland, S Rose

The main outcomes of mining grade control include defining the boundary between ore and waste and then categorising the ore according to which stockpile it should be sent. A typical workflow includes using general mine planning software (GMP) – such as SurpacTM, VulcanTM or CAE StudioTM – to create three-dimensional wireframes of mineralisation domains, which are used to flag the relevant samples of interest and constrain estimation during block modelling. Creating the wireframes is a time-consuming process, requiring reasonable software skills, patience and an eye for detail. The interpretations can be subjective; indeed, even the same geologist will give different shapes if presented with the same data at different times. The process can become particularly tedious when trying to carry out updates due to new data. It can also be difficult to test the effect of alternative interpretations or grade thresholds because of the time constraints in production.There are now several implicit modelling tools available, either as standalone programs or as add-on modules to existing GMP. In this paper, the authors develop a workflow using implicit modelling methods to show how grades and geology can be rapidly interpreted to provide effective domains for grade estimation. The paper includes case studies from open pit gold mines. The implicit modelling approach can save several days of interpretation work for each grade control drilling campaign.CITATION:Rose, S and Ireland, J, 2014. Implicit modelling applied to grade control data, in Proceedings Ninth International Mining Geology Conference 2014 , pp 115–122 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By S Wright, W Bruckard

The current status of battery collection and recycling schemes in Australia are explored in light of current developments in product stewardship and increasing pressure to decrease materials going to landfill by originating equipment manufacturers. Used consumer batteries, both single cycle and rechargeable contain a mixture of valuable metals and potentially toxic materials that may become a resource/revenue stream to offset the cost of disposal/recycling. Although the volume of batteries discarded in Australia is modest compared to other global population centres, the expected increase in battery use with increasing equipment portability and future developments in the automotive industry, provide an opportunity to recycle. The requirements for a battery recycling facility in Australia and the most promising processing platforms that may exploit the resource with enough flexibility to cope with battery developments and market trends, are explored.

Jan 1, 2006

Most coal mines in Chongqing Area are highly gassy mines and liable to outburst of coal cnd methane. In order to harness mine environment and raise the Prodction capacity, methane predrainage is generally taken as a main preventive measure against outburst by all mines. In the recent ten years, the drainage volume per year has increased from 38.25 million m3 to mote than 100 million m3 with a volume over 12 m3 per tome of coal. In some mines, the draining rate is approaching to 50 percent, the rate in mining districts is up to 60 to 70 percent. The predrainage volume accounts for one fourth of total drainage volume. All these have effectively prevented the occurrence of coal and methane outbursts.This is the current situation of methane predrainage in coal mines in Chongqing area, the methods of predrainage to prevent outbursts and related parametres comprise:1. methods, technologies, supervision and effect of predrainage in different geological and mining conditions,2. the change of methane parametres pre-and post-drainage and the analysis of the effect of methane predrainage to prevent outbursts, and3. ways to improve the effect of methane predrainage.Thus the safety, reliability and production of Changqing Coal Mines will be enhanced.

Jan 1, 1991

The treatment of the Broken Hill ores has,undergone many changes during the last ten years, and it may be of interest to some of the members to know what are the main lines on which the Proprietary Mine works at present. It must be understood that the want of absolute uniformity in the treatment amongst the various mines at the Barrier does not prove that some of the mines are working on wrong lines, for the ore is not exactly the same along the whole line of lode; this necessitates a variation in treatment, although generally only in detail.At the Proprietary Mine the ore is all mined by contract the miners are paid so much per ton for clean ore. The ore in the mine in most stopes is mixed with gangue, and the inclination of the uliners is, of course, to mix gangue with the ore, so as to be paid for as large 3 tonnage as possible. This is quite natural clean ore is easily distinguishable from clean gangue, but most lumps are a mixture of clean ore and gangue in varying proportions. The miner will naturally throw into his heap pieces which he considers still good enough, whilst the management may consider these pieces just a trifle too poor; consequently a check must be kept on this.This necessitates the first operation to which the ore is submitted. 'The trucks tare 51 cwt.; average load 21 cwt.), as they are loaded underground, have a ticket attached::showing to whiyh contract they belong on arrival at the top of the shaft they are passed over a weigh bridge...

Jan 1, 1907