Search Documents

Poorly designed sampling protocols generally result in high project risk by artificially increasing grade variability (ie the nugget effect). Sample collection, preparation and assay protocols that suit the ore type, together with QA/QC systems, will reduce this risk. All reporting codes (eg JORC, 2004) require the Competent Person to consider the quality and implication of sampling and assaying programs. High sampling errors beget higher project uncertainty; despite this fact, sampling does not receive the attention it deserves. The case studies presented show that many sampling issues frequently go unrecognised or unaddressed, resulting in poor project decisions during exploration through to feasibility and production. The overall conclusion is that correct sampling is critical to mining project success and that there is often a need for its optimisation.

Jan 1, 2007

Comalco Aluminium Limited uses a computer system for cost, supply and maintenance reporting and control at its bauxite mine in Weipa, North Queensland. The system collects data on a daily basis at a high level of detail on both cost and maintenance history. This allows useful reporting to all levels of management from the shop floor to the General Manager. The most successful aspect of the system is that the information is available in all workshops on visual display units. This allows the real spenders of the Company's money, Foremen and Tradesmen, to make well informed decisions. The system has also decreased the time taken to find parts and information which gives the Foremana greater opportunity to do his real job of supervision and quality control.

Jan 1, 1983

An extensive study was carried out to evaluate the performance of Outokumpu OK50, OK38 and Maxwell MX14 cells at ComincoÆs Red Dog flotation concentrator in Alaska. Tests were conducted by varying operating conditions of the cells installed in different circuits in the plant. The hydrodynamic and gas dispersion properties were measured and the metallurgical performance of the cells was evaluated for each condition used in the tests. This paper highlights the importance of superficial gas velocity, bubble surface area flux, gas hold-up, power consumption, residence time distribution and froth flow behaviour in optimising cell performance. The findings of these tests provide valuable insights into selection of the best cell operating conditions to optimise circuit performance.

Jan 1, 2000

This work provides a comparison between the most commonly used classification equipment in the treatment of minerals - hydrocyclones and spiral classifiers - considering their applications and costs. Although in use for decades in the mining industry, spiral classifiers have lost a lot of their importance due to the development of cyclones. This trend, however, is now being reversed, and in the last few years there has been an increasing interest in spiral classifiers, in view of their advantages over cyclones, such as: ò possibility of obtaining more thickened solids; ò less by-pass; ò great durability; ò lower operating cost. This work approaches the different aspects related to the installation, operation and costs of maintenance of these machines, giving a critical comparison of the involved costs.

Jan 1, 1993

By Samyguin VD, Filippov LO

The aim of this paper is to emphasise the importance of knowing of the rate of the elementary flotation acts (EFA) - attachment and detachment. By studying the simplest linear model notion of the column flotation, the results of the nonlinear simulaton of flotation separation in the column with lengthwise upward mixing show two principal different types of separative mass-transfer in the column. The first is, the case of a small EFA intensity, almost without the detachment. The second is, the case of a big EFA rate, when the process is close to a local attachment-detachment equilibrium. There is also an attempt to estimate the EFA rate for three different kinds of quartz particles, floated by cation collector in the laboratory column apparatus.

Jan 1, 1993

By Warren R. P

When the original Mount Gunson joint venture, between CSR and United Uranium ceased operations in December 1971, an intensive ex- ploration campaign was launched to prospect for more ore in the Mount Gunson region. This campaign resulted in the discovery of the Cattle Grid deposit. A comprehensive sampling programme proved the existence of 4.6 million tonnes of ore, at a mean grade of 2.4% Cu, calculated at a 1.0% Cu cut-off. The planning and development programme that followed this discovery included not only the mining and metallurgical aspects of the exploration of the deposit, but also the en- vironmental aspects. Preliminary work included data collection with respect to meteorology, soil types, and existing flora and fauna.

Jan 1, 1976

By Morgans DJ

The aim of this paper is to highlight the social aspects involved in the preparation of environmental impact studies (E.I.S.'s) for mining developments. In particular, the paper will reveal that the social information provided in such E.I.S.'s can achieve much more than simply satisfying government requirements. Such information can form the basis of a strategy to deal with the settlement of a mine workforce in either an existing or newly developed community. A strategy of this type can go a long way towards avoiding many of the social problems and related industrial disputes often created in such circumstances. It will also be of significant benefit to the mining company in negotiating its infrastructure package with the local authority.

Jan 1, 1987

Optimisation of mining projects is directly related to effective and efficient management of risks through the life cycle of mining projects. Effective and efficient management of risks must include explicitly all aspects of Occupational Health and Safety (OHS) through the life cycle of mining projects. This paper presents a different scale of OHS in the context of the optimisation of mining projects. Meaning of risk through the project life cycle is explained. Complex relationships between numerous risk, safety, knowledge, culture and change variables, and project life cycles are shown. The key element developed in this paper is a multi-disciplinary knowledge base that is necessary for constructive development of risk management and OHS models through the life cycle of mining projects.

Jan 1, 2003

By T Galvin

Drilling and blasting at Westside Mine near Wallsend, NSW, has presented a challenge for Orica Explosives, Australia. The colliery produces 600 000 tonnes of steaming coal per year from two seams using surface mining techniques. Tapping into underlying coal will greatly improve the yield, but there are many issues which make this an enormous challenge. Hunter Valley Earthmoving engaged Orica Explosives to supply the explosives products and to provide much of the blasting expertise that is needed on the minesite. Hunter Valley Earthmoving and Orica Explosives have proven to be an outstanding, unified technical team on this project. The success of the team is based on good communication, progressive attitudes, extensive expertise in blast design and most importantly, care and accuracy in implementing the agreed upon designs.

Jan 1, 1999

Industrial minerals and rocks (alternat ively called non-metallic minerals) are those- which are economically important because of their desirable physical or chemical properties rather than their metal or energy content. They are divided into nine classes: structural, pig- ments, process aids, ceramics and refractories, chemical source minerals, abrasives, foundry minerals, gem stones, electrical minerals. Development of deposits is influenced by the dominance of marketing,by the required range of products, the-need for specialized process- ing, place value, and the transportation and distribution of high-bulk, low-cost commodities. Evaluation is different from that of base metals because of differences in geological occurrence, sampling methods, testing, treatment, placing a money-value on the material and the importance of export markets.

Jan 1, 1973

By J P. Wyethe, D P. Padayache, B R. Green

The development of an ion exchange process for the recovery of vanadium from solutions containing low concentrations of vanadium and/or slurries is discussed. The process can be used to improve overall vanadium recovery throughout the plant, and/or to reduce the vanadium concentration of waste materials prior to their disposal. The development of the process on a laboratory and miniplant scale is discussed, and includes:selection of a suitable resin with the desired loading and elution characteristics; laboratory-scale testwork to evaluate the use of the resin in both resin-in-pulp and fixed bed configurations; recovery of a high-value vanadium product from the resin eluate; and a preliminary techno-economic assessment of the financial viability of the process.

Jan 1, 2000

By Lane D. P, Malone J. G

The slag fuming furnaces are the major bottleneck in the BHAS zinc production flowsheet. Intensification of the fuming process could significantly reduce this production restriction. Oxygen enrichment was proven to be a means of intensifying the fuming process. This procedure resulted in higher slag bath temperatures, and development work was undertaken towards obtaining accurate slag bath temperature measurement and control. Slag bath temperature measurement techniques were evaluated, with infra red optical pyrometry established as the system with the most potential for continuous temperature measurement and control. Oxygen enrichment resulted in a zinc production capacity increase of 1 000 tonnes per year. An oxygen enrichment technique was developed which both minimized the risk of furnace damage and made the most efficient use of the enrichment oxygen.

Jan 1, 1989

It is well known that in most areas of Central Europe it is not difficult to find water - usually at shallow depths - and to recover and use this water. What is much more difficult, however, is to find water sources that offer both sufficient in quantity and qual- ity. Far too often, there are sources that offer abundant quantities but of poor quality or vice versa, i.e. high quality water but insufficient volumes. In the former case where water quality is not adequate - which is more often than not due to anthropogenic factors and only very rarely a result of geogenic effects - the application of treatment techniques can help to turn such water into potable water that is suitable for human con sumption.

Jan 1, 1988

The Southern Mines Rescue Station (S.M.R.S.) has been established for 55 years and in the past 15 years has had only 4 major call-outs. Whilst the mines rescue training program has continued to expand, the Station has become involved in other work which includes mine worker training and limited research. Notwithstanding, the prime role of the Mines Rescue Station has not been overlooked and the Station has only advanced with the many changes that have occurred in the coal industry. The Rescue Station activities are financed by contributions from Colliery proprietors and the aim of the S.M.R.S. Committee is to provide a service in which colliery management and mine workers will have a high degree of confidence.

Jan 1, 1981

By A D. Ferreira, A E. C, A D. Padovezi

The increasing market requirements regarding the quality of products, the enhanced predictability from detailed mine planning, the need for process consolidation and upgrading require continuous investigation on the characteristics of different ore types to be concentrated. This paper addresses the mineralogical and technological characterisation of several itabirite iron ore types and the influence of the composition and mineralogical associations on desliming and flotation. Pellet feed quality and the influence on the major performance indicators, such as weight recovery of slimes, selectivity index, metallurgical recovery, flotation kinetics of iron minerals and gangue is also emphasised. The investigation resulted in a classification of iron ores according to their mineralogical composition, morphology of the crystals, and/or texture and microstructure of mineral particles with respect to desliming and flotation performances.

Jan 1, 2005

By Hammett PHJ

Oil Exploration Companies are primarily interested in how much oil or gas is present in the rocks in an area in which an exploratory well is drilled. The solution of this problem requires a combined effort on the part of the petroleum geologists, drilling engineers, logging and drilling contractors. To help in'explaining how the drilling and evaluation is earried out the paper has been divided into two sertions, one titled Drilling which is presented by Mr. P.H.J.-Hammett and the seeond titled Evaluation which is presented by Mr. R.M.L. Elliott. A typical Perth Basin Well has been chosen as art example for this presentation. In Figure 1A is shown the type of sandstone and shale sequence encountered in this area.

Jan 1, 1964

By Carlie JC

Many low sulphidation epizonal gold and zinc-lead vein deposits within magmatic arcs are situated on basement highs, and post-date both the main volcanic episode and porphyry copper (gold) mineralization. These features are best explained by emplacement of a flat batholith a few kilometres beneath each mineral district, as recently demonstrated by geophysical data in the Baia Mare district of Romania. The batholith provides heat for the hydrothermal system, and results in extensional faulting both through up-doming of the overlying rocks, and in some arcs through incipient collapse of the thermally weakened crust under regional extensional stress. More water-rich magmas emplaced at greater depths could explain some deep epizonal and mesothermal gold deposits situated outside magmatic arcs.

Jan 1, 1995

A survey of derelict and active alluvial tin and sapphire mines in the Emmaville area of northern N.S.W. as the first step in a pro- gramme of similar surveys to be undertaken throughout the State by the State Pollution Control Commission is presented. Thirty nine individual mine sites in the study area were included in the survey and an assessment made of the current level of impact on the environment at each site by assigning values of "magnitude" and "importance" to a number of impacting factors. Results are pre- sented in matrix form and mine sites ranked in order of impact "importance". Examples of alluvial tin, underground tin/arsenic and alluvial sapphire operations are discussed in detail and rehabilitation programmes proposed for implementation.

Jan 1, 1976

By Just G. D

Performance of draglines in large scale overburden stripping operations is critical to the efficiency of a major section of the Australian Coal Mining Industry. Optimisation of dragline productivity requires an understanding of a range of operating conditions and constraints. One of the least understood of these operations is the process of bucket filling and how this may vary with respect to variable operating conditions.Studies conducted at The University of Queensland over a number of years into this problem have enabled the mechanics of excavating to be assessed for different types of fragmented rock. In relation to bucket filling, factors such as fill volume, digging time and energy consumption have been found to be significant factors in optimising bucket design, bucket rigging and operational techniques.

Jan 1, 1992

By Yokozawa K, Yamamoto T, Kameoka Y

Japan Construction Method and Machinery Research Institute has been conducting various field surveys of tunnel works and other excavation works, and the cost and efficiency of these two excavation methods have been studied. Based on these data, the costs of blasting excavation and mechanical excavation represented by roadheaders were calculated. The costs were calculated and compared for rocks of various hardness. When the total construction cost is considered, the degree of overbreak becomes one of the most influencial factors, because the overbreak area must be filled up with expensive shotcrete in NATM. So, in the next step, the relation between the excavation costs considering overbreak and the rock hardness was studied using the data on overbreak obtained by the field survey.

Jan 1, 1987