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The necessity for agreed project outcomes, which are in accordance with client needs, and the subsequent requirement for a unique approach to managing project implementation is discussed. Reasons for appointing a separate project team to manage a project are established. The selection of a project manager, based on the services they can provide and on their characteristics, skills and management style, is discussed. The consequences of selecting the wrong project manager are explored. A broad overview of the requirements for the project team is provided. Criteria for the selection of team members, and the role played by the project manager in this selection, are discussed. The levers that drive `on-time and on-budget' projects are discussed in terms of the project's vision, goals, controls, and incentives.

Jan 1, 1997

The processes most likely to be adopted for beneficiating ores or concentrator streams containing a large proportion of particles finer than 10 um are froth flotation, selective flocculation, wet magnetic separation and selective leaching. Flotation will be made more efficient for very fine particles if ways can be found to selectively flocculate the valuable mineral beforehand (floc-flotation), to produce smaller bubbles and to reduce entrainment of ultrafine gangue. Schemes for selective flocculation have proved difficult to implement because of the delicate balance between surface forces (electrostatic, dispersion, hydrophobic) and hydrodynamic forces, that determines flocculation, and the changes which occur to particle surfaces through hydrolysis, oxidation-reduction and cross-contamination between minerals in aqueous suspensions. The search for a better understanding of selective adsorption of flotation collectors and flocculants continues and will be particularly important for the practical success of selective flocculation and selective magnetic coating.

Jan 1, 1986

By Hayes P. C

The kinetics of reduction of PbO-silicate melts in CO-N gas mixtures at 900¦C have been studied. Rea~tion rates were measured by moni- toring the CO2 content of the product gas. A wide range of gas and melt compositions and gas flowrates have been investigated. The overall reaction rates in heterogen- eous systems are typically characterised by a steady increase as the gas flowrate is in- creased. At low flowrates the processes are limited by gas film mass transfer. At high flowrates it is expected that the rates will tend to maximum values determined by either the rate limiting chemical reaction or diffusion in the condensed phase. In the present series of experiments it has been found that for any given gas composition the overall reduction rate goes through a maximum with increasing gas flow. The maxima, which occur at relatively low gas flows, are more than an order of magni- tude greater than those observed at high gas flowrates. The results of these and other experiments are presented and analysed. Possible rate limiting mechanisms in the reaction system and their implications regarding commercial reactors are discussed.

Jan 1, 1987

The growth in the nickel market and the price increases predicted in 1970 have not mat-erialized. Several plants have been construct-ed, particularly to treat lateritic ores. A spectacular increase in cost of energy and the escalation of capital costs have led to severe economic difficulties on the part of many nickel producers. Several of the nickel prod-ucers joined together to form a Nickel Develop-ment Institute in 1984 with the prime objective of improving nickel markets. Most producers have taken exceptional action to cut overall costs as well as unit costs. Another organiz-ation made up of nickel producers, NiPERA, was established in 1980, to study and take action on problems of nickel in the environment and especially in the workplace.Ion exchange, and particularly continuous ion exchange, has been developed into a reli-able commercial unit operation in the last dec-ade. An example of how ion exchange combined with hydrogen reduction can be integrated into a Caron type reduction roast ammonium carbonate leach process for the recovery of nickel from laterites is discussed.

Jan 1, 1985

Ion exchange resins are an attractive alternative to activated carbon in both column and resin-in-pulp processes for the recovery of gold from cyanide solution. Resins are widely used for this purpose in the Soviet Union apparently in preference to activated carbons.A wide range of resins are available and the high level of resin technology is demon-strated in the resin processes used to recover uranium.The anionic gold complex, Au(CN) 2 , is selectively adsorbed onto weak and strong base resins. However other anionic cyanide complexes, cyanide ions and other anions from the process water are also adsorbed onto resin sites. Resin selectively for gold is not as high as it is for activated carbons. As a result similar gold loading capacities are obtained for resins and carbons when used in plant liquors.

Jan 1, 1984

By Z W. Orndorff

Excavation through sulfidic geologic materials during construction activities has resulted in acid rock drainage (ARD) related problems at numerous (>40) locations across all five geologic regions of Virginia, USA. Potential acidities ranging from >100 to develop a statewide sulfidic materials risk map; document ARD impacts to soil and water quality and engineered structures; and develop methods to assess site-specific risk potentials within a given highway corridor. A statewide sulfidic materials GIS risk map was developed based upon the state digital geology map which assigned four levels of relative risk to all mapped strata based upon predicted lime requirements and probabilities of encountering highly reactive materials. Non-highway construction activities have also routinely disturbed sulfidic materials, and a recent airport project in northern Virginia resulted in over 150 ha of extremely acidic (pH 45 mg/L) run-off from this site heavily damaged a receiving stream, partially due to the fact that it dissolved the galvanised steel water control structures in stormwater detention basins, leading to direct discharge of run-off and sulfidic sediments. The airport area was treated and revegetated in 2002 with a combination of lime-stabilised biosolids, straw mulch, and acid-tolerant grasses. Water quality in a receiving second-order stream quickly responded to the treatment, but some release of N was also noted as a secondary effect. Collectively, these results point out the importance of accurately assessing the potential for excavation of sulfidic materials in construction environments, and the necessity of developing toxic materials handling strategies similar to those employed in mining environments.

Jan 1, 2003

By White B

The domestic and commercial use of underground space dates back to Neanderthal man living in caves. There are many examples worldwide of the imaginative use of underground excavations, either left by mining or purpose-built. World living trends indicate that an increasing percentage of the population is living in and around major cities. Environmental, social and economic pressures associated with urban expansion can be partially catered for by a well-planned and integrated underground space regime. This paper addresses the types of underground development that are complementary to the economic and environmental pressures associated with urban expansion and high density cities. The paper explores the implications of mining and exploration technology and civil engineering, as well as the ancillary professional disciplines (legal, architecture and planning, sociology and education).

Jan 1, 1997

By Coskun B

The classification of selective mining units (SMU's) and the assignment of grades to those classified SMU's are very important in open pit mining, especially for precious metal mining. During ore control planning, the classification of mineral

Jan 1, 1998

Ore petrology will fundamentally determine the types of metallurgical processes employed for ore treatment, their operational efficiency and the nature of processing problems encountered. It is therefore paramount that the petrological charact

Jan 1, 1998

Tailings facilities tell a story to the public about how the mining industry manages its activities. They also create a risk that must be managed for the long term. All the knowledge and technology is available to safely design, build, operate and decommission tailings facilities.   Tailings at Waikato North Head Minesite are pumped as slurry, over long distances and against high static discharge heads to backfill the excavated area. WNH is, under the mining licence, obliged to reconcile the topography of mined areas to the closest possible resemblance of the original terrain. The active tailings areas are located near main operational facilities and detailed plans and procedures have been developed to ensure a safe and continuous operation.   The concentration plant is designed as two identical and independent plants. Each plant has its own tailings slurry pumping system.   This paper represents a general overview of the tailings disposal practice at WNH mine site. It discusses tailings delivery, construction and water management.

Jan 1, 2004

A good deal of criticism has been levelled at Mines Division over the slowness of processing mining privilege applications, some of which is justified and some which is not. There are many reasons for delays in the processing of applications and not the least of these delays are caused by the applicants themselves.

Jan 1, 1982

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

Stope control information at the C.S.A. mine is obtained by diamond drilling inclined holes from within the stapes. Practical mining outlines are determined from complicated ore contours by a joint mining engineering and geological study. Production holes to achieve this outline are individually marked up and checked. Stope control also extends to selective mucking of ore mixtures for metallurgical reasons and to marginal ore and waste mixtures for economic reasons.

Jan 1, 1969

In-situ leaching of gold deposits has not become an option largely as a result the lack of suitability of cyanide as a lixiviant due to sluggish kinetics and high dependence on the availability of oxygen. A second problem area is the excessive cost of drilling the required number of injection and production wells needed to service a wellfield capable of maintaining any significant throughput or providing and acceptable level of gold production. Well spacing in in-situ leaching operations is limited by solution life, dissolution rate, and the need for solution control. With cyanide the life of an active solution capable of dissolving significant gold is severely limited by the availability of oxygen which cannot be readily replaced while the solution remains underground. The extremely slow gold dissolution rate also necessitates excessive contact periods in order to dissolve coarse gold.

Jan 1, 1991

By Miovski P, Hooft P. V

In the majority of recently commissioned gold mines granular activated carbon is used to adsorb gold from alkaline cyanide pulps or solutions. At the same time the carbon also adsorbs many other inorganic and organic species, most of which lower the activity of the carbon. Removal of these foulants is necessary before the carbon is reactivated and recycled. Standard practice for re- storing carbon activity involves high temperature treatment in a kiln - an apparently straightforward unit operation which is not always satisfactorily carried out. This paper presents the results of some fundamental work carried out on the thermal reactivation of carbon in a laboratory rotating pot kiln. The effects of temperature and steam addition on carbon activity were examined and compared with the activity of carbons obtained from a number of commercial kilns. Carbon was also reactivated using a small-scale Rintoul Furnace in which carbon was resistively heated by the direct passage of an alternating electric current. It was established that both elevated temperatures and the addition of steam to hot carbon generally enhanced its activity although peat-based extruded carbons responded a little differently to coconut shell types. Other measurements made included the weight loss and the hardness of carbons as a function of reactivation conditions.

Jan 1, 1987

Gravity concentration of tin at Renison Limited uses tables and spirals to treat the various coarser fractions produced from sulphide flotation tailing. An acceptable final tailing cannot be made from one pass over the tables and spirals and therefore the tailing from these separators is reground and combined with the sulphide flotation tailing as the feed to the classification section. The gravity section became increasingly overloaded in the years preceding 1976 due to efforts to maximize tin recovery to the gravity concentrate. In April, 1976, two 2DSV Reichert cone concentrators in series were installed to treat the table and spiral tail- ing stream, prior to regrind, to scavenge a small tonnage of hard, coarse low tin grade material for rejection to final tailing. Gravity section loadings were decreased markedly, allowing operator attention to be directed more to table performance than to spillage collection. An increase in mill throughput of approximately 15% was possible following the commissioning of the Reichert cones. The cones are currently operated to make the minimum tonnage of tailing consistent with reasonable- gravity section loadings.

Jan 1, 1978

Estimation of operating costs in the nickel production industry requires a detailed analysis of material flows from mine to smelter to refinery. Despite the small number of nickel producers compared to other base metals, the existence of two very different ore types (sulphide and laterite) and a wide variety of mining and processing technologies make the identification of these flows of critical importance if an accurate global picture is to be obtained. Smelting and refining processes in nickel metallurgy have evolved with a high degree of adaptation to specific operating conditions in different locations. Overall costs are calculated by combining individual cost elements for each unit in production chains from mine to saleable metal product. The average cost of western world primary nickel production in 1995 was US$2.07/lb ($4560/tonne). Average operating costs remained virtually unchanged in the three years to 1995 after an 8.5 per cent fall in 1993, but a 3.9 per cent increase to $2.15/lb is expected for 1996. A major factor in this rise results from the lower prices of copper and cobalt this year, reducing the by-product credits available to major producers.

Jan 1, 1996

By Dunstan N, Valentine C

Gas power was first used on the Sons of Gwalia mine in January 1911, when a twin-cylinder Crossley engine of 167 hp was installed to belt-drive a 112 kw 550-volt ac generator. This engine was connected with a No 8 Crossley up-draught suction gas producer, using mulga charcoal as fuel.A second Crossley engine, of 400 hp direct-coupled to a 550-volt ac generator, was installed in 1912, and operated by a down-draught wood producer.This was followed by a large Kynoch twin tandem four-cylinder engine, rated at 660 hp, sea level, with a rope drive to the crushing and treatment sections of the plant.These engines operated until January 1921, when the plant and power house were destroyed by fire. After the fire, both Kynoch and second Crossley engines were salvaged and reconditioned and they continued to give useful service for some years.

Jan 1, 1932

By Mozley R

Contaminated sediments are a multinational problem. A crucial factor in solving an environmental problem is knowledge of, not only the amounts of polluted soil, the contaminants involved and their concentration, but also the historical background of the problem. Processing polluted soil is a tailor made activity based on rational decisions resulting from a detailed treatability study. Lack of information about characteristic properties of a specific sludge/pollution combination is the main obstacle in the route from first ascertaining that a particular harbour subsoil is polluted, to final identification of the full scale treatment plant. In the first instance, information must be generated regarding the distribution of pollutants in relation to the distribution of the original geophysical components. Based on this information rational decisions can be made on separation at a particular cutpoint and what sequential techniques should be involved for a certain fraction. For this purpose a `fingerprint method' is presented especially developed for investigation of polluted soil and sediments. The heart of the fingerprint method is a series of sequential hydrocyclone separations, by which a series of products is generated. The objective of the fingerprint method is to select an optimised treatment procedure in which the pollutants are concentrated in as small a volume of material as possible, leaving the bulk of the material clean. The pollutants can then readily be destroyed or isolated from the environment. The philosophy and advantages of the fingerprint method are demonstrated for a harbour sludge containing heavy metals as main pollutants. Hydrocyclone separation combined with flotation of both the coarse and fine fraction resulted in reusable and dischargeable products. Flotation of the fraction of fines was carried out by means of an experimental flotation cyclone enabling the selective recovery of mineral particles with diameters less than 10 microns. The overall conclusion is that design and engineering of treatment flow schemes for polluted dredged materials is a tailor made activity based on rational decisions resulting from the fingerprint information.

Jan 1, 1993

By Rintoul AH

Studies of many types and purposes are being carried out constantly by mining, minerals processing and other operating companies. Frequently, the staff requirements and special skills lie outside the resources of the operating companies, and needs arise for external consult- ing services. We examine the natures of a range of studies, the factors that influence whether they be carried out in-house or externally and then discuss the manner of execution. Aspects of both good and bad practice are highlighted in order to arrive at the basic principles that give the most benefit from study work. While the bulk of the discussion relates specifically to the execution of external studies of process plant projects, many of the observations can be applied equally to the execution of studies by one department of a large organisation for another, and also to studies of capital projects other than those involving process plant facilities.

Jan 1, 1975