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A model of dense medium cyclones is developed based on balancing the terminal velocities of the discrete particles due to the centrifugal force against a random turbulent eddy velocity. An expression of the form P - or Q _ 1 100 e."A where P is the partition number., is a function of cyclone efficiency, particle size and density differential between the particle and medium, and is the slurry spilt, is developed and may be used for regressing plant partition data. The above model provides an understanding of peculiarities of the partition curve such as asymmetrical tails, elevation of the cutpoint and elevation of the d50 with increasingly fine feed. The effect of feed variables such as particle size, medium viscosity and changes in spigot or vortex finder diameter is shown. A means of convoluting the partition curve with various feed washabilities is discussed together with how the above may be used to evaluate plant performance for a variety of feeds.

Jan 1, 1987

By Yamamoto Y, Ohyama H

In case of NATM, mechanical cutting is desirable in view of the original purpose of not spoiling natural ground. As typical tunnelling machines, there are two (2) kinds available: one is "Full Face Excavator" known as TBM (tunnel boring machine), and the other is "Roadheader" known as Part Face Excavator. By the use of the former, accurate profile cut is made possible, but there is a limit in the shape of a cutting section. By the use of the latter, cutting of various sections is made possible, but in order to cut a section economically and accurately, operators are required to have a high level of skill. In this text, we introduce Automatic Controlled Profile Cutting System (hereafter "ACPC" System) developed as a roadheader.

Jan 1, 1987

By Turco E, Pelizza S, Castellani F, Stanganelli V

Excavation are in progress for the building of tunnels of the waterworks in West Campania (Naples). The works afferent to part II envisage tunnelling through a miocenic clay formation over consolidated by two tunnels whose sections are respectively 50 and 10m2. Tunnel blasting is carried out by mechanical means. An excavator is used in the big tunnel, whereas in the small tunnel a roadheader machine is used for a short tract and a mechanized shield is used over a long stretch. The tunnel feature complex problems regarding stability. This is particularly so for the big tunnel whose face appears unstable. For this reason the clay on the face is sistematically bolted by means of 3-metre and 12-metre bolts. This prevent the use of a TBM for tunnel Excavation.

Jan 1, 1987

When mining of ilmenite deposits wet process of preparation is traditionally used. But this method needs large volume of water. The problem of water deficiency is characteristic of many regions of the Republic of Kazakhstan. The Satpayevskoye ilmenite deposit is situated in the East Kazakhstan, its location has problems with water, and the mineralogical composition of rock is unfavourable: rocks contain up to 40 per cent of clays. That is why designers made a decision to use dry process of preparation for processing of these ores. Offered scheme and equipment selection are presented in this paper.

Jan 1, 2003

This presentation opens with a definition of technology and how it is implemented. The expenditure and progress on R&D in the mining industry is then investigated and found to be difficult to quantify. The needs and interests of that industry including contribution to this Congress are examined and it is concluded that short-term rather than long-term goals seem to be prevalent. The presentation concludes with the opinion that the answer to the question in the title is both affirmative and negative but overall there is a need for the mining industry to become more innovative.

Jan 1, 1990

By Goode RA

It is-assumed that a pipeline system is economically justified as a means of transportation.. The terms "True Life" and "Economic Design Life" are defined. The most usual design alternatives to be considered from both physical and economic -viewpoints are listed and a summary is given of the main factors to be costed in assessing the relative economics of each alternative. A brief statement of the recor mended method af economic. assessment is given and an example is included. The paper aims to present a reasonably accurate, simple and practical method of considering the main economic factors which govern design.

Jan 1, 1962

By Thuli AJ

Copper concentrate from Bougainville's copper mine located on the west slope of the Crown Prince Range on Bougainville island, is pumped 27 km to the filter and drying plant at Anewa Bay for preparation and storage prior to shipment to overseas customers. Prior to shipment the thickened concentrate slurry is passed through a test loop to check that its consistency and pH are acceptable for transportation through the main pipe line. The Bougainville pipe line is unique since it is the world's first copper concentrate system. where slurry is pumped an appreciable distance against a high head,

Jan 1, 1975

By Leigh J. H

A history is given of the dust control techniques developed and applied by the mining companies at Broken Hill. A history of the regeneration works undertaken since 1936 is out- lined. Particular emphasis is placed on the stabilization of mine residue dumps which are located throughout a belt of mining leases in the middle of the city and which began in 1937. The establishment of vegetation for dust control techniques is discussed in detail and a case study is given of the successful revegetation of the sides of a 650 metre long, 350 metre wide and 35 metre high residue dump.

Jan 1, 1976

By P Hofmeyr, D Pretorius

Iron ore, which is transported by rail from the iron ore mines at Sishen in the Northern Cape, to the Saldanha Iron Ore Terminal in the Western Cape, needs to be analysed while loading to be exported. Every shipment will be sampled and an average analysis of the ore will be produced which is required by the purchaser at the receiving port. On arrival at the iron ore terminal at Saldanha, the ore is tipped from the rail trucks onto conveyor belts to be either stockpiled or direct-loaded. The conveyor belts run under the sampling plant and the ore is sampled periodically by means of an automated cross-belt sampler. This is the first iron ore port sampling facility in which the automated sampler is situated above the conveyor belts and not adjacent to them. A portion of the primary sample taken off the belt is moved to the dedicated sampling laboratory situated behind the cross-belt sampler and over the conveyor belt lines. The sample is split in the laboratory, one split being used for moisture and particle size determination and the other part is dried and then analysed by means of X-ray fluorescence spectrometry (XRFS) on fusion beads for major and minor elements. Particular care is taken to obtain high quality data for penalty elements.This sampling plant is completely automated and from the primary cross-belt sampler to final analysis by XRFS no manual steps are involved. This has meant that some processes are used which are suitable for automation and are ISO compliant but not necessarily ISO-certificated. The ISO manuals were developed with manual laboratory processes in mind. Precautions are also taken to maintain the integrity and representativity of the samples. This paper is a case study?describing?the automated sampling systems used at the Saldanha Iron Ore Terminal sampling facility and laboratory from conveyor belt to analysis.CITATION:Hofmeyr, P and Pretorius, D, 2012. Automated sampling of iron ore for analysis at the Saldanha Iron Ore Terminal in South Africa, in Proceedings Sampling 2012 , pp 25-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By M Dorricott

This paper describes the design, construction and performance of sill pillars using cemented development mullock at the Crusader Gold Mine. The orebody is some 35 m - 60 m in length, 5 m - 8 m wide, dipping at 60¦ - 85¦ and plunging at about 40¦ to the north. It is accessed via a footwall decline. The ore occurs at the contact between basalt and ultramafic. This contact is characterised by shearing and alteration; and is prone to unraveling failure. The cut and fill mining method at Crusader extracts 25 m high ore blocks in four flat back lifts and one 8 m thick crown pillar. To enable full recovery of these high-grade crown pillars with minimal dilution, a 5 m thick sill pillar is constructed using cemented rock fill (CRF), after mining of the bottom two lifts in each block. Uncemented development mullock is used as rock fill (RF) for subsequent lifts. Development mullock and cement/water slurry is mixed underground to produce CRF. The fill is transported to the stope in LHDs and dumped on the floor. The sill pillar is advanced progressively, with compaction provided by the loader driving over the previously placed fill. Old jumbo rods are installed as shear pins along the flat dipping hangingwall to reduce the risk of rotational failure of the pillar. A fan of cable bolts is installed into the hangingwall to prevent unraveling failure in the sheared ground. Buffer blasting is used to minimise damage to the CRF sill pillar when the crown pillar below is extracted. At the time of writing, extraction of the crown pillar underneath the CRF has taken place at the 930 stope. The crown pillar was extracted successfully with dilution from the backfill and hangingwall minimised and 98 per cent of the gold recovered. This compares with pillars that were mined beneath uncemented backfill where only 70 per cent of the gold was recovered and where there was significant dilution from the backfill and from hangingwall failures. Where no CRF was placed, there were also numerous production delays caused by large rocks from the hangingwall blocking the stope brow.

Jan 1, 2002

By W Gale

Rock and coal fractures together with micro seismic vibration is a common occurrence during mining, however, it is very uncommon for coal and rock to be propelled into the roadway. Irrespective, such occurrences do occur and appear to require significantly more energy than is available from strain energy release during coal cutting. The sources of energy which can contribute to the propulsion of coal from the face or ribs are typically strain energy from the surrounding ground, seismic energy from a rapid rupture of the ground in the vicinity, or rapid expansion of gas from within the burst source area. The aim of this presentation is to briefly review the mechanics of a coal burst and to discuss the mining situations for which the energy is sufficient to create bursts. A brief discussion of alleviation strategies is discussed. This is an abstract only. No full paper was prepared for this presentation. CITATION:Gale, W, 2018. An overview of coal burst phenomena, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), p 2 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

German coal mining suffers from rock temperatures up to 600C which are the same as in South Africa at 3000 - 4000 m of depth. Therefore cooling plants have increased in the last decade and today a cooling power of nearly 200 MW is installed in the total Ruhr District. Cooling a mine is a little bit different from cooling a bottle of beer in a refrigerator in the kitchen because the heat taken from the bottle of beer is delivered to the kitchen some centimetres away; in mining the cooling-problem is more difficult: here the bottle of beer corresponds to the airflow at the coal face and the kitchen to the surface, So it is necessary to transport the heat or the "coldness" a long distance. In the address by Ieuan Morris some systems for transporting heat from the coalface to the evaporator of the cooling machine and further from the condenser of the machine to a return airflow were described. The following is a short idea of the way this problem is treated in Germany.

Jan 1, 1983

By Zenari L, Kent D

As our mines introduce more sophisticated production technology into their operations, the dependence on communication systems is markedly increased to allow the management of the technology. However the attention given to the communication systems has lagged that given the production equipment - namely LHDs, trucks and jumbos. At times it was treated as after thought. However, this is changing as the degree of automation increases in our mines. The communication system is now being given much more priority and is genuinely becoming a part of the mine design. The transfer of information around underground, as well as between the surface and underground, is an essential day-to-day activity, with the aim being a smoothly run operation. However the mine environment is far from static, and situations arise - such as breakdowns or other incidents - that require swift analysis of the issue, its cause and its remedy. Also, as communication systems become more sophisticated their use in areas, other than direct data flow, become available. The importance of communication, its development, and new areas being impacted by communication is the subject of this Paper.

Jan 1, 1997

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

A method is presented for calculating the number of cycles of stress to failure of a drill rod from operating variables; a mathematical analysis by Cooper of the stresses present in drill steels is applied to the forged collar, i1i-in. hexagonal hollow drill steel in common use in Australia; and an estimation is made of the dry fatigue limits at various points along a drill rod.It is shown that these calculations predict failure at a 'point where failure rarely occurs, and do not predict that failure should occur where it does in practice. The reasons for this anomaly lie in the neglect of bending stresses in the stress calculations, and in failuredue to corrosion fatigue at a preferred section rather than to simpler fatigue under non-corrosive conditions.INTRODUCTIONIt has long been recognized that failure of metal sections by fatigue is influenced both by the number of cycles of stress imparted to the section (N) and by the magnitude of this cyclic stress (8). In this paper, both Nand Shave been calculated for rods which have failed in service, and whose operating history is known. While the calculation of the number of cycles to failure is·simple, the calculation of stress is more complex. The results of stress caIculations predict that failure should occur only hi short rods, and then preferentially at the tip end rather than the shank end.However, in actual fatigue failures of steel rock drill rods, approximately 75 per cent. of such failures are close to the shank end, and failures near the tip end are rare.The usual explanation given for this high incidence of shank-end failures is that at the point of failure there exists, in forged collar steels of the type common in Australia "hardness valley" or. "m'etallurgical notch". This narrow valley in hardness is a weakness, and failure is expected to occur at the weakest point at the bottom of...

Jan 1, 1955

ON milling plants, where a large number of slime samples are collected each day, considerable work is involved preparing them for the assayer. The usual practice (as the material usually passes a 150-mesh screen) is to place the sample on a 30-mesh screen an 1 brush it through on to a cloth below. The sample on the cloth is mixed and a portion taken out for the assayer. A simple apparatus that would rapidly disintegrate and prepare these slime samples for the assayer was needed. The manufacturers of assayers' supplies appear to have overlooked apparatus for this class of work. To overcome the tedious preparation of slime samples by the above method, the writer devised the apparatus shown in the accompanying drawing (Fig. 1). It will be seen that the apparatus is a combination of a modified household flour sifter and a riffle sampler.The apparatus is made up in two parts, the top half consisting of a screen box carrying the disintegrator, and the bottom half a, riffle divider, the joints between the two being a slip-in fit. A lid is provided for the screen box. The disintegrator consists of an open drum, to which are soldered three rows of spring steel fingers. Each row has a number of steel fingers which, on rotation, press against the semi-circular screen in the screen box, forcing the slime particles through.To operate the apparatus an 8-in. sample tin is placed under each spout of the divider. The sample of slime, which is about 2 lb. in weight and usually in lumps, is placed in the screen box, the cover replaced, and the drum rotated about half-a-dozen times by means of the handle.The disintegrated sample is divided by the rifle divider into two portions, which are found in the tins under the spouts of the apparatus. One of these samples is taken, mixed on a sheet, and sent to the assayer.

Jan 1, 1922

The expense of mine environmental and planning process approvals is a fundamental and proper part of mine planning and feasibility costs. It is not a cost that should be the subject of challenge nor is it a cost that should be avoided. However the additional process approval costs incurred by bureaucratic delay, process duplication and administrative incompetence is a scandal and a deterrent to investment.

Jan 1, 1992

Gunpowder Copper Limited processes 1,000 tonne/day of Mammoth ore in a conventional flot- ation concentrator. Run of mine ore is prepared for flotation by three stages of crushing and two stages of ball milling. The concentrate, in which the primary copper mineral is chalcocite, is solar dried and exported to Japan. The history of operation is summarised, and plant practice and metallurgical problems are discussed.

Jan 1, 1974

By A B. Christie

The Institute of Geological and Nuclear Sciences' Mineral Resources Programme is currently carrying out research under two major projects:   HAREM (Hauraki Andesite Rhyolite Epithennal Mineralisation) The Hauraki Goldfield lies within a belt of andesite-dacite-rhyolite volcanics of Miocene Pliocene age which is underlain by a basement of Mesozoic greywacke. It contains some 50 separate epithermal gold deposits and is a world-class gold and silver producer. The HAREM project is aimed at improving models of the epithermal gold mineralisation, and to better understand the processes and controls of origin, transport and deposition of the gold.   MARGO - (Marlborough Gold) The MARGO project is aimed at determining the geological factors that controlled the formation of the Mesozoic mesothermal gold-antimony-tungsten deposits in the Marlborough Schist belt. Following reconnaissance work on 12 deposits, our current work is concentrated on deposits in the Wakamarina valley.

Jan 1, 1994

By B Cope, N Hastings, D Webb

A Feasibility Study was completed in late 2002 to ascertain the risk and reward profile from the proposed deepening of operations at Perseverance Nickel Mine in Western Australia. The system and approach adopted to this brownfields extension work is outlined and the main components of the study are overviewed. In particular, emphasis is given to the integration of mine design and scheduling tools through to financial evaluation. Detailed comment is given on the ability of the system used to provide a robust project schedule complete with 3D animation. The level of importance in eliminating scheduling errors is demonstrated in relation to the reported bottom line viability of the project. It is suggested that this is an area where brownfields Feasibility Studies have lacked clarity and authenticity, leading to the creation of an unrealistic benchmark for project implementation.

Jan 1, 2003