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By Thompson P, Sharma Y

The paper describes the methodology and results from a study carried out by Telfer Gold Mine to optimise the materials and costs involved in construction of the pad for their dump leach operations. The investigation involved large-scale field testing of five different types of liner and a number of different cushion and drainage layer configurations. The aim was to identify the most cost effective construction methods to allow the final dump height to be increased from 45 in to 60 in without causing significant damage to the liner. The effects of dump height on permeability were also investigated. These methods are described and results presented. The findings indicated that modifications to the existing liner/cushion layer/drainage layer configuration used previously at Telfer would actually reduce overall construction costs rather than increase them despite an increase in overall dump height. Relative construction costs are presented.

Jan 1, 1994

Cerro Matoso (CMSA) in Colombia produces ferro-nickel from lateritic ore containing approximately three per cent nickel, using a Rotary Kiln - Electric Furnace (RKEF) process, in which the calcining of the mineral within the kiln is second in importance only to the smelting of the mineral in the Electrical Furnace. This article discusses the installation and operation of an expert system to control the kiln of CMSA. In the CMSA process, the run-of-mine ore is crushed, homogenised, dried and mixed with a small percentage of coal, before being heated up to 900¦C in a rotary kiln in the presence of natural gas mixed with air in a controlled proportion (air/gas constant ratio). The final objectives of the process are the following: ò To reduce to a minimum the iron and nickel oxides in order to convert these into metallic ions; this is a reduction process to facilitate largely the smelting in the electric furnace. Since the reduction is made with natural gas, it is much more economical than the subsequent complete reduction in the electric furnace, since electrical energy is much more expensive by unit of processed mineral. ò To heat the mineral as much as possible to facilitate the subsequent smelting. ò To eliminate totally the moisture content of the ore. An expert system with fuzzy logic was commissioned in 1994 for the control of the kiln and it has operated with good results ever since.

Jan 1, 1996

Gold recovery by catalytic copper ammonium thiosulphate solution has been studied. Such a process strategy is very attractive for leaching certain difficult-to-treat ores and presents lessened lixiviant toxicity compared to cyanide. Newmont Gold Company has evaluated the ammonium thiosulphate heap leach process for gold recovery from low-grade carbonaceous sulphidic refractory ores following biooxidation. The ammonium thiosulphate leach process has been studied in laboratory, pilot plant and demonstration scale. Satisfactory test results support the continuation of process development. However, the thiosulphate leach chemistry was found to be very complex. Maximum control of the stability of the leaching system is a key factor for success, especially for the heap leach process. Important solution chemistry is discussed in this paper.

Jan 1, 1997

By Rowley M, Bradford P

Plutonic Resources Limited (formerly known as Pioneer Mineral Exploration Limited) delineated, developed and operates the Plutonic Gold Mine located 180 kms northeast of Meekatharra, Western Australia. Gold mineralisation was discovered in the Marymia greenstone belt by Great Central Mines NL (GCM) in 1988. There was no previous, recorded gold mining activity in the area. In May 1989, Plutonic Resources Limited (PRL) entered into an agreement to acquire a 51 per cent interest in the three Mining Leases containing the Plutonic deposit from GCM. Subsequently in December 1989, PRL acquired the remaining 49 per cent interest in the Mining Leases. PRL and GCM are also involved in a 51:49 regional joint venture on extensive Exploration Licences in the vicinity of the Mining Leases. Following due diligence validation, reserve delineation and testwork, a feasibility study was undertaken in conjunction with JR Engineering Services, which led to the financing and development of the project for operation in August 1990.

Jan 1, 1991

By H Lehtonen, H Mansikkaviita

In primary copper smelters, the received copper concentrate and other materials contain a certain amount of moisture, ranging from six to 14 per cent. Moisture in wet concentrate has a negative effect on the performance of the smelting furnaces when it is fed directly to the furnaces, namely increasing the energy consumption and the off-gas flow. There are several drying technologies available for drying copper concentrate, varying from direct heated rotary dryers and flash dryers to indirect heated steam dryers. Application of steam dryers has changed the drying process for copper smelters. Produced from a waste heat boiler, steam as heating medium enables plant-wide heat utilisation. Fossil fuel used from outside sources to remove water is no longer required and the combustion chamber is not required. In addition special attention has been paid to overcome the known problems of pollution emissions, excessive wear, clogging and frequent maintenance. The Kumera steam dryer is featured with many advantages based on principal improvements in reducing tube element wear and increasing drying efficiency. Thus, it has been considered as the first choice for those smelters where steam is available.

Jan 1, 2006

Shear-flocculation is one of a munber of potential processes for upgrading deposits of finely-grained minerals and, more generally, for separating different types of particles suspended in a fluid.The smaller the particle the more likely it is to follow the fluid streamlines, or be entrained within turbulent eddies, and the less likely it is to deviate from the streamline and attach to bubbles (froth flotation), other particles (selective flocculation) or magnetic poles (wet magnetic separation). As shown in Figure I, a number of ingenious ideas have been proposed to overcome this effect. The suspended particles are assumed to be 1 - 10 µm.Thus, the efficiency of attaching ultrafme particles of the valuable component (solid circles) to air bubbles, as in process A, is poor. The efficiency may be improved by attaching the particles to oil droplets (Ralston, Kart and Newcombe, 1984) to form agglomerates that rise or sink (B), to magnetic particles (C) (Parsonage, 1988) to allow recovery in a magnetic separator (D), to other particles to form aggregates (E) that are then either attached to bubbles (F) or recovered by sedimentation (G) (Warren, 1992), and to pieces of polyethylene (Rubio and Baltar, 1991) that rise or sink (H).In A, C, E, F and H, the forces that are generally used to ensure collisions result in adhesion are hydrophobic forces, hydrodynamic forces and inertial forces (Warren, 1992). These drag particles from the streamlines to allow particle-particle adhesion. In B and E, soluble polymeric molecules have been added to bridge between particles as they approach closely during a collision.The second major consideration is selectivity. Selective adsorption of the hydrophobe or polymer onto the valuable particles is the key. Many subtle effects of surface chemistry are involved in obtaining adequate selectivity. A complication in real systems is that the initial suspension is often naturally coagulated and needs to be dispersed before being selectively flocculated.

Jan 1, 1993

In the past ten years or so there has been a renewed interest worldwide in the processing of refractory gold ores. The Archean province of Western Australia contains both numerous and major gold deposits, and has a long history in the development and practise of treating refractory ores (eg Blaskett and Woodcock, 1953). Depletion of shallow oxidised ores in recent years has re-focused attention on deeper sulphidic ores, and as a consequence has renewed interest in treatment methods for those ores which are refractory. Mineralogical factors he at the heart of reasons as to why these ores are refractory, and are the key to designing and improving treatment options in the longer term. This paper presents an overview of mineralogical factors that are relevant to the processing of refractory gold ores in the Archean of Western Australia. It is based on a number of research projects and other work on a variety of gold deposits, mainly in the Eastern Goldfields region, carried out over the past five years or so.

Jan 1, 1991

By Grace B, Cunningham D

The poor quality of bore waters available to the Australian mineral processing industry creates a climate for crystallization of calcium based scales. If ignored, calcite and/or gypsum buildup can cause loss of production and costly unscheduled maintenance. This paper discusses the factors which contribute to scale forma- tion, methods used to monitor buildup and preventative measures (mechanical and chemical) that can be used. A case history il- lustrates the value of using chemical antiscalants.

Jan 1, 1991

By C E. Loo

The cohesive zone has a significant influence on blast furnace operation and performance. The high-temperature behaviour of the reducing ferrous burden determines the properties of the cohesive zone and is studied in a laboratory using a softening and melting test. This paper summarises recent work aimed at better understanding the physico-chemical changes in a ferrous bed during softening and melting. Using a combination of standard, non-standard and quenched tests supported by optical image analysis, this work has highlighted some important differences in behaviour between lump, pellets and sinter as well as between the two lump ores and two acid pellets. As with the two lump ores, one pellet is denser than the other and the denser ore/pellet is also higher in silica.Within the cohesive zone, densification of the ferrous layer leads to reduced permeability and greater pressure drop. From the work presented in this paper, two key mechanisms of ferrous layer densification were identified. Firstly, the formation of fayalite, which melts at low temperatures, can act as a lubricant between particles and lead to densification of the ferrous layer under load. Secondly, reduction to metallic iron is topochemical and fayalite in the outer shell of the particle restricts gas flow to the centre and results in the formation of a wustite core. As temperatures rise, the wustite melts and eventually exudes out of the shell, occupying void spaces between particles and further reducing layer voidage and permeability.This work has shown that density and silica content are two key factors that result in increased densification of the ferrous layer. For porous Australian lump ore, the higher porosity and lower silica reduces the formation of fayalite and limits the formation of the wustite core, ultimately leading to a more permeable bed. The difference between the porous and dense ores was more pronounced with the introduction of prereduction to better simulate blast furnace conditions. This suggests that a porous ore gives significantly better cohesive zone permeability and blast furnace operations than a dense ore.The behaviour of fluxed sinter particles is different in that the silica reacts with lime to form dicalcium silicate. Minimal wustite core forms because relict hematite particles in sinter are only small and reduction occurs uniformly throughout the particle. Even with significant loss of material through prereduction, beds formed from sinter remained comparatively rigid. Studies using a typical blast furnace burden mix of 80 per cent fluxed sinter and 20 per cent porous ore showed that the structures of these beds at softening and melting temperatures are very similar to the sinter-only test. Measurements of bed contraction and pressure drop also confirmed that the introduction of 20 per cent porous ore into a sinter bed did not alter its properties. This is an indication that 20 per cent ore can be easily accommodated by blast furnace burdens.CITATION:Loo, C E, 2015. Important acid ferrous burden properties in the cohesive zone of a blast furnace, in Proceedings Iron Ore 2015, pp 367–376 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The paper examines the possibility of applying the monolithic packing technique developed in the UK to the division of wide development drivages in Australia, so enabling double entries for longwall retreat panels to be created from shortwall units. The monolithic pack of the UK therefore becomes a monolithic partition in this proposed Australian application. A method developed for the analysis of the load development in packs installed behind longwall advancing faces is adapted and used to predict the support performance of the monolithic partition. Conclusions are made regarding partition construction and possible rates of advance.

Jan 1, 1986

BlIP Minerals is a large, diversified, international mineral producer. This paper describes the company's operating strategy, and identifies the role of mineral processing in this strategy through three examples: the column flotation installation at Escondida in Chile, the leach-SX-electrowinning plant, proposed for Escondida, and the whole-ore roasting process being constructed for the Syama gold operation in Mali. It is concluded that the application of appropriate and sometimes novel mineral processing technologies can achieve significant benefits in reduced operating cost, improved product quality, and in some cases the exploitation of previously uneconomic deposits, thereby providing strategic advantages to the company.

Jan 1, 1993

By Adhikari G. R, Raju N. M

The breaking of rock by explosives occurs so rapidly that the details of the phenomenon cannot he observed by the unaided eye. High resolution cameras and VCRs offer a means of slowing down the blasting action. A high resolution super video camera with digital zoom and a variable shutter speed was imported and used for the first time in India as a tool for blast optimisation studies at Malanjkhand Copper Project. Slow motion play-back revealed that the gases vented out through the fissures. The crest moved prior to the lower portion of the bench when initiated with detonating cord. The delay timing between the rows was not enough to provide sufficient relief and rock movement. This inadequate delay timing resulted in flyrock from the back rows. Stemming ejection was observed from practically all the holes. The muck profile was not satisfactory. A trial was carried out using 450 ms in hole delays and 25 nis surface delays. The front row holes were drilled based on the observations made from the laser profiling survey system. The video of the monitored blast showed that the rock started moving prior to the stemming ejection. It could be clearly seen that the entire block was completely initiated through the surface delays before the onset of the burden movement, thus eliminating any chance of misfires. Viewing blasts in high quality slow motion was useful to arrive at modified design parameters, resulting in uniform fragment size distribution and controlled rock movement.

Jan 1, 1995

By A Coulson, J Hussey

Noranda Inc is a Canadian mining and metallurgical company with its activities managed through businesses in copper and recycling, zinc, aluminum, magnesium and various metals through its interest in Falconbridge Ltd. Noranda operates three base metal mines, three copper smelters, one copper refinery, one zinc refinery, one lead smelter and refinery, three copper recycling and sampling facilities seven aluminum producing facilities and one magnesium production facility in the construction stage. The mining side of Noranda has a strong history of open stope, cut and fill and shrinkage mining. The 1999 Noranda Annual Report lists a 206 million tonne resource located at Porphyry Mountain in GaspT, QuTbec. Mont Porphyre is a large tonnage, low-grade porphyry style Cu-Mo deposit that was discovered in 1994. It is located at a depth between 1.0 and 1.7 km below surface and characterised by a very competent rock mass. The Mont Porphyre resource is located adjacent to the town of Murdochville, close to NorandaÆs Mines GaspT operations. Mines GaspT closed its open pit and underground operations in 1999 after approximately 45 years of mining, but still operates a copper smelter near Murdochville. The low-grade and great depth of the Mont Porphyre resource suggested that mine design could not be based on the conventional Noranda open stoping mining practice. This paper will review NorandaÆs approach to evaluating the Mont Porphyre deposit. The approach included two definition diamond drilling campaigns, a review of current caving practice, an in-house scope study, a geotechnical logging program for diamond drill core and participation in an international study on cave mining. One interesting component of NorandaÆs approach was the scope study that involved a team of multi-disciplinary personnel drawn together for a short period of time. The objective of the scope study was to determine what conditions would be necessary to mine the deposit and to assess the merits of continuing with further exploration work. A review of current worldwide underground bulk mining practices, and in particular an evaluation of the applicability of caving mining methods, were key components of the scope study. The scope study team concluded that derivatives of caving could be applied to the mining of Mont Porphyre, but additional diamond drilling was recommended to further define the deposit and improve the level of geotechnical information. Following the recommendations of the scope study team, a diamond drilling campaign was completed during the summer and fall of 1997. The 1997 drilling campaign had two secondary objectives, in addition to the primary objective of defining the limits of the orebody. The first objective was to improve the level of geotechnical information available for the characterisation of primary block cave fragmentation. The second objective was to improve the delineation of a lower grade intrusive core. A geomechanical investigation was conducted and included particular emphasis on geotechnical data collection and analysis. A review of the actual data collection process, including several trials of different core orientation techniques, will be included in the discussion.

Jan 1, 2000

The major incentives for developing continuous processes for the production of formcoke are to achieve a wider range of coals which can be used, greater operating flexibility enabling the production of various coke qualities, and environmental improvements. The characteristics of a formcoke which must be considered when assessing its performance in the blast furnace are compressive strength, abrasion resistance, volatile matter, reac- tivity, porosity, density, size, shape, ash yield and sulphur content. Lurgi's development work in attempting to pro- duce a formcoke which meets the specified requirements has resulted in most current efforts being concentrated on the Bergbauforschung/Lurgi hot briquetting process. This process blends hot char produced from a non-caking coal with small quantities of caking coal in a special mixer in the plastic range of the caking coal. The material is subsequently briquetted hot, then subjected to a thermal after-treatment to produce a strong abrasion resistant formcoke. A 650 tonne per day plant for British Steel Corporation is now under construction. A study of the equipment requirements and the operating costs indicate that the economics of large scale formcoke plants compare favourably with those of conventional coke-making plants.

Jan 1, 1975

A thousand writers have harped upon the wondrous nature of the inventive faculty. They realise that man is a creator, and that capital and labour alike are, and will always be impotent without machinery and processes that is invention. What Bacon has said is echoed by them all, "the introduction of new inventions seemeth to be the very chiefest of human actions. The benefit of new inventions may extend to all mankind-they make all men happy without injury to 'any' they are new creations and imitations of God's own works." My remarks will occupy another field I will refer to some of those features of the Patent Laws of different countries, which prevent the use of new inventions, oppress the development or inventive' genius, and diminish human happiness and progress' Wherever Patent Laws are framed and administered upon wrong principles, these results are inevitably found. A concise, complete, common-sense comparison of the chief Patent Laws of the world cannot easily be found but to avoid seeing scrappy, misleading references to Patent Law in the press particularly the English-would be equally difficult. Writers who are considered authorities so frequently make minor issues prominent and so uniformly fail to give weight to fundamental principles that the effect on the public is to mislead.

Brisbane based and listed on the ASX, Eastern Corp is pursuing the development of coal projects in New Zealand. There are various reasons why New Zealand coals are of interest û substantial resources, stable political/economic environment, close to Asian markets. In just over 12 months, Eastern has secured an operating coal mine (Cascade) and a prospective exploration area (Whareatea West), both on the Denniston plateau region, on the south islandÆs west coast. A key focus of activities is the development of relationships with key stakeholders and the promotion of the local economy.   Certain barriers may exist to the entrance by foreign companies into the New Zealand coal mining sector. These include geological challenges provided by the heavy faulting of the coals, port and rail infrastructure constraints, and the ægreenÆ factor.

Jan 1, 2005

By Granholm S

The current emphasis within the mining industry to reduce the cost of production has stimulated interest in the fields of maintenance and operational reliability of capital intensive mining equipment. From an economic point of view, high reliability is desirable to reduce the maintenance costs of the systems. Two graphical methods consider reliability analysis. The first one, the method of Total Time on Test (177)-plotting deals with the reliability data which are free from trend and serial correlation. The second method which is based on time dependent modelling approach deals with the data which are not free from trends and serial correlation. The examples show how these graphical methods can be used to calculate the optimal maintenance intervals for components or systems.

Jan 1, 1991

By Tapp BA

Australia, considered an energy and mineral resource rich country, is poised on the verge of a major mineral industry 'boom'. It has been repeatedly emphasised that this growth in the mineral industry will form the basis of future economic development. Currently the mining and mineral processing industries use some 32% of the annual primary energy consumption in Australia. This share, although large even now, will increase with the realisation of the 1980's production expansions to 40% by 1985. Two metal industries dominate the energy scenario; iron and steel and aluminium. Major expansions in the local industry will be dominated by the aluminium industry. This highly energy intensive industry has planned major increases in metal production throughout the eighties. The implications of exporting cheap energy to pay for expensive oil imports, the ramifications on Australia's infrastructural ability to supply these major energy needs and the other options that might be

Jan 1, 1981

By T Iwadachi, T Fujisawa an, G R. Alvear

A large amount of Be2C and BeO is formed during the Cu-Be alloy production process, because beryllium is a highly reactive element. Carbide and oxide formation impairs the production yield and the quality of the Cu-Be alloy products, and therefore should be minimised. As a first step for solving these problems in the process, the following thermodynamic properties of the Cu-Be-C-O system were investigated. Based on the results, the equilibrium relations of the Cu-Be-C-O system were clarified and the operational conditions of the current Cu-Be alloy production process were also examined and discussed.

Jan 1, 2000

Severe development difficulties were experienced soon after in-seam mining commenced at Appin Colliery in'1962. Thirteen years later no significant pro- gress had been made in overcoming some aspects of this development problem. Some success had been achieved in destressing roadways both in development and pillar extraction. Longwall retreat mining had shown promise of being highly productive but at an extremely high cost in terms of development requirements both in number of roadways and intensity of support in those roadways. No real advance was made in the problem of driving the first heading of a group of headings under conditions of apparently high stress in directions other than the preferred mining directions, although failure of the roof in this heading did seem to give easier work in the subsequent headings driven particularly if they were driven on narrow centres.

Jan 1, 1976