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A universal grinding circuit model suitable for an arbitrary structure of flowsheet has been suggested. In this model classifiers and mills are described in a most general form. What puts the model in a class by itself is the automatic mass balancing in all streams of the circuit. In order to provide this a special classifier model is adopted. A previously published continuous steady state process model is used as a grinding model. Non-linearity of classifier model leads to a resultant circuit model which is equivalent to a non-linear integral equation. It complicates somewhat calculation algorithm in comparison to that of linear model, but provides a physically meaningful solution.

Jan 1, 1993

The reliable estimation of ore reserves in mineral sand deposits depends on drilling methods and assay techniques that have been specially developed within the industry. Improvement of these techniques is a continuing process, as variations within and between deposits are highlighted during the actual mining operation. Constant monitoring of metallurgical losses along with mineral production allows comparison of mineral tonnages accounted for by mining, with original calculated reserves. A review of ore reserves in the Jerusalem Creek field from scout drilling in the sixties, through mining in the seventies, shows the progression from understatement prior to mining, to the present when more than two thirds of the reserves have been depleted.

Jan 1, 1979

A methodology is described to integrate heap leaching into a CIP operation. The paper firstly describes what is meant by a 'systems approach'. A broad view of the objectives of integration of heap leaching into CIP is given, followed by the components of the system, and then a description of the methodology for integration. The seven stages of integration are given as determination of distribution of gold, sampling, metallurgical testwork, conceptual study, pilot heap operation, pit modelling and pit optimisation. The final result is a series of optimised curves which determine the maximum value of the orebody, and the optimum cut-over grade from CIP to heap leaching.

Jan 1, 1992

The design of drawpoints in caving and stoping mines has a significant impact on the productivity of the operation. Drawpoints must be designed to provide uniform drawdown and maximum recovery of the broken ore within the limits imposed by the dimensions of the stope, the stability of the pillars, the method of draw, material flow characteristics, etc. The design of drawpoints historically relied on the mining engineerÆs experience and intuition. However, in many operations, empirical analyses have also produced important information regarding design geometry. Factors that affect the sizing and spacing of drawpoints are discussed and guidelines are provided for their design in order to obtain maximum recovery of broken ore and reduce hang-ups.

Jan 1, 2000

Expert systems have been employed in a number of areas for a considerable number of years. However, the traditional long development times associated with these systems have restricted their application. With the advent of powerful Expert System Development Tools such as COMDALE/X and the use of efficient development techniques, the time required can be drastically reduced. This results in the availability and applicability of this technology to a wide range of applications. This paper discusses some of the 'rules' which indicate amenability (or otherwise) of a particular problem to an expert system solution. Various problem types are examined and these are illustrated with reference to examples of their use at various operating sites.

Jan 1, 1991

By Seedsman R

The fundamentals concepts of roof support are similar between coal mining, metal mining and tunnelling and yet there are different design approaches, different hardware, and different levels of site investigation. This should not be the case and this paper discusses the key geotechnical issues that should underlie all roof support design - the need to reinforce defects. A design method to build a beam in laminated rock under high horizontal stresses is presented. The method allows for changing rock strengths, defect properties and varying horizontal stresses. At one level the design can be implemented with design charts and tables. Lessons learnt during the implementation of the designs at 5 different mine sites are Discussed.

Jan 1, 1998

The short review of hydrogeologic conditions in the three Polish coal basins have been presented as the background for the prevention measures against water inrushes being underta- ken in coal mines. The Polish mine safety regulations concerning water inrush prevention have been discussed, namely: - classification of sources of the potential water inrushes, - levels of water inrush risk and conditions of mining operation in the mines facing particular risk levels, - determination of the -di.mens.ons.of protecting pillars to prevent water inrush to mines, protection of surface water reservoirs and their earth embankments in regions submitted to mining deformations. Three examples of coal mining being carried out under water bodies have been presented.

Jan 1, 1988

Modern off-highway trucks have evolved over 30 years from small 20 ton units to vehic- les with capacities of up to 170 tons. Diesel engines are used by all manufacturers while transmissions are either mechanical or electri- cal. Development over the years has kept pace with component availability from engine, trans- mission and tyre manufacturers.Computer simula- tion studies are recognised for purposes of vehicle evaluation and costing under various op- erating conditions. Several manufacturers are currently manufacturing or evaluating vehicles with capacities of up to 260 tons. This paper describes the essential facts associated with the operation of off-highway trucks of the rear dump type in the mining industry.

Jan 1, 1973

Mary Kathleen Uranium Ltd. recommenced operations in early 1976 following a twelve year period of care and maintenance. Several sections of the plant were modified or completely changed for the second operation. The most important change was the replacement of ion exchange with solvent extraction as the means of purifying and upgrading uranium rich Isolutions Most of the problems experienced in the solvent extraction system originate from the leach liquor which has a strong tendency to form stable emulsions. This has been countered by some careful control of leaching conditions and by closer observation of operations in the solvent extraction area. Most problems have now been resolved and plant recoveries are quite Satisfactory.

Jan 1, 1978

By Paine G

Kidston Gold Mines commenced mining in 1984 and currently mine approximately 10 million tonnes per annum of ore and waste using a conventional truck and shovel open pit method. The overall mine grade is a low 1.82 grams per tonne.The mineralisation is generally uniform within the ore zones and mining boundaries are staked out from blasthole assays according to pre-determined cut-off grades. Buffer blasting is necessary to minimise post-blast lateral movement of in-situ grade for digging control.The characteristics of the rock currently mined vary widely from soft oxidised to hard unweathered rocks. Blasting problems have been experienced during the initial mining phase in these harder rocks.

Jan 1, 1986

Kalgoorlie Consolidated Gold Mines Pty Ltd (KCGM) is a management company, formed in 1989, to manage the assets and operate the Kalgoorlie joint venture for the owner companies Gold Mines of Kalgoorlie Limited (GMK) and Homestake Gold of Australia Limited (HGAL). Mining is still in progress on the 'Golden Mile' and surrounding areas more than 100 years after Paddy Hannan's discovery adjacent to the active Mt Charlotte mine. From 1893 until 30 June 1995 the Kalgoorlie Goldfields has produced approximately 45 million ounces (-1400 tonnes) of gold from mining and treating about 179 million tonnes of ore. This production equates to about 20 per cent of the total Australian gold production and about one per cent of the world's

Jan 1, 1996

The Effect of Grinding Aids on Laboratory Grinding of a Cassiterite-Polymetallic Sulfide Ore

Sep 13, 2010

In the face of intense global competition and other business pressures on coal miners, ongoing quality initiatives and continuous process improvements are needed to enhance business performance. By viewing a minesite in terms of key processes, rather then departments, and employing innovative technologies and better applying organisational resources, there exists enormous potential to achieve reductions in process cost and time.

Jan 1, 1998

In a stipulated hard rock situation, drilling and blasting costs per tonne in open cutting or underground operations are comparable. In open cuts the drilling and blasting costs per tonne of ore are multiplied by the waste ratio.Conventional underground loading and haulage practices are so batch-oriented that the cost per tonne of ore handled is a large integral multiplier of open out costs per tonne loaded and hauled.If underground costs are to be reduced to compare favourably with open out costs then loading and hauling practices underground must be converted to a non-batch continuous system. This can be achieved by utilising gravity to control ore to mobile crushers feeding conveyors running direct to surface.

Jan 1, 1985

By C Deacon

It is common practice to include microspheres or similar density reducing agents in inherently insensitive water-based commercial explosives to achieve detonative sensitivity in the absence of chemical sensitisation. It has recently become possible to similarly include microspheres in LDAN (low density ammonium nitrate). Further to previous studies and publications to determine the benefits resulting from the use of microsphere enhanced LDAN technology in blasting, additional advantages are described in this document. These include range tests at independent testing facilities (Universal Tech Corporation û USA) which reflect results observed in the field, and support theoretical assumptions made when the products were introduced. Additionally, on-site studies in opencast pits using Heavy-ANFO blends incorporating modified LDAN, show that monetary savings can be realised through significant advantages gained in plant throughput and explosives use.

Jan 1, 1999

By Groves J

The sizing and classification circuits at the Mt. Newman Beneficiation Plant have performed satisfactorily. Investigations have been aimed at solving minor problems and achieving small' improvements. Emphasis has been placed on cost reduction rather than metallurgical performance. It has been found that some circuits will give better performance with the sieve bends removed. 1.0 BACKGROUND Mt. Newman. Mining operates a major iron ore mine in the Pilbara region of Western Australia. Rainfall is sparse (average 250 mm/year). Current mining is all above the water table. What rain there is tends to run off quickly instead of soaking in. The total operation produces about 30 Mt/ year of saleable product. Most of this product comes from high grade crushing plants where ore from the quarries is simply crushed and conveyed to product stockpiles. About 3 Mt/ year comes from the Beneficiation Plant.

Jan 1, 1984

By Li T

Mining of the southern 1900 copper Orebody presented a challenge due to the complex geology, geometry and simultaneous extraction of the nearby lead/zinc/silver orebody. An integrated and co-operative approach was adopted, involving geology, geomechanics, mine planning and production personnel. Successful extraction of the first 1900 Orebody stope, T496, together with the extraction of the first two lead/zinc/silver panel stopes in the immediate hangingwall of the 1900 Orebody stope was achieved as a result of this approach.

Jan 1, 1995

Major exploration companies can have a problem with what to do with small precious metal ore bodies located through exploration programmes. Low tonnage, but high grade, ore bodies too small to justify in-house development.1.2 Ban Ban Mining is a Sunshine Coast based partnership with considerable expertise in mining and earthmoving which specializes in the mining of small/medium size ore bodies on behalf of the tenement holder on a profit sharing or royalty basis.1.3 The partnership's first successful venture has been the mining and vat leaching of a small 40,000 tonne ore body with a head grade of 5 gm/tonne gold and 32 gms/tonne silver, situated near Ban Ban Springs in southeast Queensland.1.4 This paper looks at the low cost vat leaching method of treatment, as an alternative to CIP and CIL in the processing of low tonnage/high grade precious metal ore bodies.

Jan 1, 1990

Three transient phenomena have been observed and experienced in the operation of large solvent extraction mixer-settlers. These relate to the ability of the settler to discharge streams with low entrainments arising from different phase separation æproblemsÆ. The operation of large-scale laboratory and commercial solvent extraction settlers has been shown by a number of workers to be a dynamic process, especially at the feed end. Circulating flow patterns are common in all three organic, aqueous and emulsion phases. The circulating patterns in deep dispersion bands in long settlers are believed to form roll fronts that can travel down the settler length within the bounds of the dispersion band. Various physical models are proposed to illustrate the formation and movement of roll fronts within the dispersion band. Another transient phenomenon has been observed in commercial settlers operating without any dispersion band. Entrainment of the continuous phase in the advancing dispersed phase is at high and erratic levels. This supports the conventional separation model, which recommends the presence of a significant depth of dispersion band to æfilterÆ the secondary haze from the bulk separated phases. The third transient is the position and shape of the dispersion band within the settler. Large commercial settlers have been shown to exhibit high variability in both these aspects of the dispersion band. The elimination of all three transient phenomena in commercial settlers has been shown to be effective with an in-settler media of coarse size and moderate specific surface area. The effect of the media is two-fold: it dissipates both the circulating flows and the forward velocity of any roll fronts, and creates a stable deep dispersion band at the feed end that serves to trap secondary haze from the primary coalescence process. It is effective in treating both types of transients involving non-existent or excessive dispersion band depths. The media serves to enhance coalescence by providing a static surface of intermediate surface tension on which droplets can collapse. The random nature of the media also provides multiple stream splitting and re-combination, that presents further drop to drop and drop to media impingement, which in turn promotes coalescence.

Jan 1, 2000

This paper reviews the role of fill in mining including consolidated fill both histor- ically and currently as determined by a recent survey of the Fill Subcommittee of the Canadian Advisory Committee on Rock Mechanics (CACRM). It covers the application of fill in modern min- ing methods including mechanized cut and fill, undercut and fill, post pillar cut and fill and longhole pillar recovery between stabilized fill. An automated fill preparation plant and recent developments in rotary drilling of hydraulic fill conducting holes are described briefly. The paper also summarizes the findings of some of the important laboratory and field work carried out on the behaviour of fill in Canada, the United States and Australia and again draws on current information obtained from the Fill Subcommittee of the CACRM. Space limitations and unavailability of suitable material prohi- bit the summary of similar information from other countries.

Jan 1, 1973