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By J Kok

"In some underground mines it has been observed that the primary focus during feasibility studies is to determine the best way to mine the defined orebody. Some studies have been conducted without sufficient consideration of the ventilation and cooling requirements or the risk from exposure to associated airborne pollutants caused by the mining operations.Following the hierarchy of control to manage risk, numerous problems of the ventilation systems in some underground mines could have been avoided if sufficient consideration was given to the ventilation requirements to manage heat, airborne pollutants and leakage during the feasibility study phase. If the constraints and hazards were well defined and understood at the time of the study, efforts could have been made to eliminate or substitute the hazards to decrease the risk. Some of these problems include but are not limited to: primary fan locations heat loads diesel exhaust ventilation design based on the production requirement fire/emergency response strategies.This paper highlights areas in the ventilation discipline that are sometimes overlooked during feasibility studies. It will also highlight the importance of the Ventilation Specialist during these studies. Experience and knowledge of best ventilation practices must be applied in feasibility studies.As a result of adequate consideration to all ventilation aspects in the feasibility study phase, risks will become lower in terms of health, safety, production loss and equipment downtime caused by heat.CITATION:Kok, J, 2014. Feasibility studies – what should be considered in terms of ventilation, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 197–204 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

The purposes of defining the mining environment for underground mass mining and the uses of characterisation data are outlined. The requirements for data in the areas of geology, surface and groundwater hydrology, topography and environmental constraints and geotechnical studies are identified. Emphasis is then placed on the collection and interpretation of geotechnical data for establishing the in situ stress regime and for rock mass characterisation. Methods used for diamond drilling, core logging, borehole logging, data analysis and presentation, rock mass modelling and rock mass classification are outlined. Finally, recent and potential advances in the state-of-the-art are identified in areas such as geophysical methods, measurement while drilling, computerised data collection and analysis, rock mass modelling, in situ stress measurement data presentation and interpretation, and some applications of rock mass characterisation data.

Jan 1, 2000

This paper presents an overview of the strategy adopted to bring the Ballymoney opencut lignite deposit to an advanced stage of mine design and confidence. Certain aspects of the project differentiate it from the normal Australian experience. These include the thick overlying glacial drift, the proximity to established infrastructure and the wide fluctua- tions in annual lignite demand. The incorporation of these factors in the mine plan are discussed. The deposit area is located near the town of Ballymoney, in Northern Ireland. In July 1986, after winning an internationally competitive tender, Meekatharra Minerals Ltd commenced an exploration programme designed to delineate reserves to supply a 450 MW power station. In less than eighteen months, a complete evaluation was undertaken and a price submitted in December 1987 to the relevant authorities for the supply of lignite. Subsequently, UK government consultants and significant inter- national banks have endorsed the findings. The mining study commenced with the evaluation of various develop- ment strategies, followed by selection of the most viable mining method and equipment. The equipment selected will mine four million tonnes of lignite and eleven million cubic metres of waste each year. In year 15, the waste removal requirement increases to almost seventeen million cubic metres. This results in an average strip ratio over the mine life of three cubic metres of waste per tonne of lignite. The quality of the product delivered to the run of mine conveyor transfer point, based on maximum resource recovery, will include heat content of 8813 kJ/kg (3789 Btu/Ib), ash content of 28% and moisture content of 40%.

Jan 1, 1989

The task of designing stable high walls and spoil piles in strip coal mines, and stable openings with controlled roofs and floors in underground collieries - within the constraints normally imposed by economics - depends upon a reliable assessment of rock mass strengths and rock mass reactions under a variety of stress conditions. Of the geological factors influencing internal friction and cohesion within rock masses, many may be determined qualitatively or empirically from bore-hole evidence. Rock types, descriptions and properties of intact rocks, location of boundaries, limits and degrees of weathering, potential for slaking or decomposition of rocks when exposed, bedding characteristics, the nature of rock anisotropy and the likely effects of water on rock mass properties can be assessed from bore- hole data. Discontinuities, whether they be major such as faults and dykes, or minor such as joints and fractures, present a greater problem, and in most instances the mine geologist must resort to additional techniques to describe or predict their occurrence, nature, frequency, intensity or physical properties. Information on ground water and seam gas is available from bore-holes within certain levels of reliability.

Jan 1, 1977

By H Bartosiewi, M Kuruppu, F Mashiri

Wire ropes are one of the most heavily used components in a dragline. They are subjected to harsh conditions during the regular usage of a dragline in a mining operation. Hoist ropes are subjected to fatigue due to the cyclic nature of load handling as well as due to rope bending over the sheaves and the drum under load. This leads to wire breaks due to fatigue. Accumulation of a number of wire breaks close to each other can have a detrimental effect on the rope. Furthermore, to allow for the increasing demand for higher load capacity coupled with the inconvenience of having very large ropes, the factor of safety is often compromised, which increases the wear rate. Drag ropes are also subjected to heavy loads. More importantly, they are allowed to drag along the rough mine surface subjecting them to external physical abrasion. This makes the life of drag ropes one of the lowest among those used in a dragline. Suspension and IBS ropes are relatively uniformly loaded during their regular usage although they need to withstand dynamic load cycles as well as bending. Hence they tend to last for a number of years on average. The paper analyses the wear types and their severity of each of these rope applications, and suggests methods to determine rope wear rates and the resulting rope life. The paper further gives suggestions for good operating and maintenance practice that can extend the rope life and help reduce the large expenditure associated with every major rope change in a dragline.

Jan 1, 2005

The areas of impact when employing high productivity long wall systems are reviewed and the financial implications of the most significant areas highlighted. A distinction has been made between availability and utilization. The need for more efficient delay recording, together with increasing control and utilization of the systems has been identified and the measurability of the latter discussed. The increased use of electronic delay reporting direct from the operating unit as the basis for operational control and a pre-emptive maintenance philosophy is seen as an important area of achieving higher performances from existing long wall production systems and Configurations.

Jan 1, 1988

The .subject of this paper is to briefly outline various methods of stockpiling and reclaiming, and the use of different types of bucketwheel re- claimers and stackers in these operations. The paper examines briefly the different types of bucketwheel equipment, their operations and relates them to different stockpile layouts, giving examples of their application in Australia.

Jan 1, 1973

The seemingly insatiable world demand for mineral and energy products is continuously pushing out the frontiers of exploration and development in countries around the Pacific Rim.

Jan 1, 1990

By Slechta JJ

The performance of a hydrocyclone treating fine coal has been examined over a wide range of feed and operating conditions.The results were expressed in terms of partition curves from which the water split to the oversize flowstream,the corrected separation size and reduced partition curves were determined-.The following conclusions were obtained. (a) The water split to the oversize flowstream was found to be dependent upon the vortex finder and spigot diameters of the cyclone and the flowrate and solids content of the feed slurry. (b) The corrected separation size was dependent on the solids content of the feed,and the vortex finder and spigot diameters.The hydraulic pressure (or flowrate) of the feed slurry did not have a significant effect.This phenomenon could be explained in terms of crowding of the particles at the Spigot.

Jan 1, 1984

By Nilmani M, Fountain CR

Injection of gases into slag-melt mixtures produces various zones as a result of bubble formation and disintegration within the melt. The extent of these zones depends on the type of reactor used. When compared with ferrous processes, non ferrous processes are character- ised by large bubbles formed adjacent to the tuyeres, low flowrates and shallow tuyere sub- mergence. These features can result in a greater proportion of reaction occurring above the bath, more refractory wear and tuyere blockage with more splashing. The large bubble zone adjacent to the tuyeres has been investigated using the tech- niques of physical modelling, mathematical modelling and plant trials. Large bubble form- ation in physical models was recorded using a high speed camera and a rapid response pressure transducer coupled to an oscilloscope and data recorder. It was found that the bubble volume (Vb) could be correlated at low flowrates using the single bubble model Vb = 1.378 Q6/5 g-3/5 Deviations from this correlation occurred with increasing gas jet momentum. Plant trials were carried out on a copper converter at Mount Isa Mines during five different charges. Pressure measurements were made through the tuyeres during the slag blow and commencement of the copper blow. The power spectrum density showed that the dominant pulse amplitude occurred at a frequency of approximately 3 pulses/sec. Plant data from this and other converters were correlated using the same relationship as for physical modelling. De- viations occurred due to the state of the re- fractory, bath composition or bath circulation effects.

Jan 1, 1984

Since the mid-1970s there has been increasing attention in the South Pacific area to the problems of disaster planning and management at various levels, mainly from regional through national to provincial levels. This concern has been expressed in a variety of ways. International aid donors have made their views known in commentaries or reports. Seminar discussions have been organised at the regional level (such as at Suva, 1976; Suva, 1979; Tonga, 1982 and Suva, 1983). In-country training workshops or meetings have been organised (such as the "Disaster Preparedness Workshops for Non-governmental Organisations" in Pacific countries, jointly run by the Australian Red Cross and the Australian Overseas Disaster Response Organisation and supported by AIDAB, in Vanuatu, 1985; Solomon Islands, 1985; Western Samoa, 1986; Fiji, 1987; Tonga, 1987; Lae and Port Moresby, Papua New Guinea, 1988) or held outside the area (ACDC at Macedon, 1981). Training and/or research institutions have been established such as the East-West Center, Honolulu, and the Asian Disaster Preparedness Center, Bangkok (more Asia oriented). As part of the East-West Center Pacific Islands Development Program's Disaster Preparedness Project, a detailed manual of disaster preparedness and response procedures and guidelines has been published (Carter, 1984).Table 1 and figure 1 show that the area with which this discussion deals is a highly fragmented island region, comprising many small, some minute, nations, both in land area and population. The social structure is predominantly rural, with the capital city often making up a small part of the total population and, in absolute terms, little more than a small town. Outside the administrative and governmental activities concentrated in the capitals, in most cases the indigenous inhabitants depend on subsistence agriculture or on usually a monocultural concentration on a cash crop, most frequently coconuts.

Jan 1, 1990

Oxidation or sulphidization of the surface of pyrrhotIte partIcles enhances atomic interdiffusion at elevated temperatures and provides a mechanism for interface growth between particles in contact. In a mass of pyrrhotite-rich ore or tailing, where oxidation heating is not controlled, bonding of particles by diffusional mass transport contributes significantly to the agglomeration of the mass.

Jan 1, 1976

The object of this paper is not to describe any particular type of engine in close technical detail but rather to give a general picture of past and present practice in this important section of the industry. The subject involves the study of almost 600 years of coal mining history which has fluctuated from stagnation to extremely rapid progress.Up to the year 1300, coal was obtained from outcrops and exposed beds, but this easily worked source soon gave out, so by that time shafts had to be sunk to the coal seams, and coal mining proper commenced its career.These early shafts were very shallow, and winding equipment was not a matter for much concern. Raising coal was generally achieved by human labour, which was called "coal bearing." Coal was loaded into baskets. strapped to a man's back, and carried from the underground workings to the pit bottom. The unfortunate individual then climbed ladders to the top of the shaft, unloaded the basket, and descended the shaft for the next load. Men, women and even children, were employed as the mine expanded, and were generally bound to the colliery for life, performing daily work which would now be regarded as slavery. This primitive method of raising coal to the surface was slow, inefficient and highly dangerous, yet for want of a better method it continued until in 1602 it isrecorded as having been abolished in Wales, one of England's great coal districts. It was not until 100 years later, however, that it was abolished in the northern coalfields, and the colliers were freed forever from their dreadful life.WINDLASSThe first step towards winding coal was the introduction of the windlass. This was similar to the common windlass used over a well, and was operated by man power. The...

Jan 1, 1945

This paper provides a financial perspective to the valuation of Australian resource companies and projects. Valuation exercises need, however, to be seen in the broader context of a thorough business appraisal, one that incorporates all disciplines employed in the resources industry. Fine tuning a discount rate or determining a particular capital structure is likely to be less important to valuation than an adequate understanding of industry dynamics and a company's likely performance in future years.

Jan 1, 1989

By G McSpadden

At September 2001 the beneficiation plant at BHP Billiton Iron OreÆs Mt Whaleback mine is set to treat 9.5 million tonnes per annum (Mtpa) of iron ore, 40 per cent better than original design. This paper describes the steps, decision-making processes and innovations used to increase capacity at minimum cost. The plant was designed in 1979 to operate at 1133 t/h for 6000 hours per annum, treating 6.8 Mtpa. Sufficient suitable contact ore was unavailable and feed was finer than planned. The plant was designed with minimum surge capacity between multiple process units. It had never reached design capacity. In 1993 a study by Fluor Daniel to treat increased tonnage resulted in modifications to improve plant operations. Efforts to expand production by increasing reliability did not achieve the desired capacity. NJ Morrow (Pty) Ltd (NJM) conducted a technical audit in 1996 with process evaluation by Mineral Processors. Replacement of operator interface and PLC logic in 1997 made plant operation and diagnosis easier. Involving operators in logic development enhanced their plant knowledge. Fluor Daniel Simulation developed a simulation model of the process. Mineral Processors and NJM reviewed the model findings, recommended metallurgical improvements and developed preliminary designs and costs. BHP Engineering produced a detailed design with a cost estimate of $A34 million. After analysis and revision of the design, a $A10.4 million upgrade to 8.5 Mtpa was carried out. Detailed modifications to the process units, particularly the HM drum plant, allowed significantly higher capacities and improved metallurgical performance. The target capacity was achieved in June 2001. Further modifications are progressing to treat lower-grade ores.

Jan 1, 2002

The Mt Leyshon Gold Mine is located 30 kilometres south of Charters Towers in Northern Queensland. The current open cut mine has been in operation since 1986. In 1992 a feasibility study was completed that recommended an increase in production to over 240 000 ounces of gold per year. This proposal required an upgrade of the processing plant to five million tonnes per year, and an enlarged mining fleet to provide additional ore, and to meet the increased waste removal requirements. The implementation of the mine expansion program during 1993 required the Life of Mine plan to be extensively revised. This required the assessment and management of potential risks associated with the mine design. The updated geological model using the 1992 drilling results along with the actual contract mining and processing costs were used to establish a series of nested optimised pit shells. The total and incremental quantities and costs were then analysed to determine a suitable pit perimeter. The pit and phase plans were then created and used to devise a staged development plan. The block layout plans for each bench were then established from which a detailed life of mine production schedule was created.

Jan 1, 1994

By Semple DG, Leach TM

A continued exploration programme has further defined the geology of the Tolukuma vein system, verified the resource indicated by Newmont, and identified potential for additional mineralisation. The resource at Tolukuma Hill, designated as Zone C, is a measured 440,000t @ 17g/t Au and 46g/t Ag with an additional indicated resource of 120,000t @ 16g/t Au. A diatreme breccia localised at an intersection of structures, and a relationship of gold to base metal sulphides, are highly indicative of a porphyry association. Typical epi-thermal features such as crustiform banded quartz and quartz pseudomorphing. platy calcite are also present and locally contain lesser gold mineral-isation. Pre-existing dilatant structures have acted as a host to the ore fluids, resulting in the formation of the semi-continuous Tolukuma-Gulbadi veins over a 1100m strike. A fluid flow model suggests that mineralising fluids were sourced from the diatreme margins and migrated laterally along dilatant structures. Bonanza gold grades are derived through fluid quenching in the flexure between a hanging wall split which hosts much of the Tolukuma Hill resource and the feeder graben structure. Thus, the relationship between the pre-mineral structural geometry and fluid upflow at the margins of a diatreme breccia, controls the ore setting. Potential for more ore remains within the Gufinis and the 120 veins as well as in the outlying Prospects.

Jan 1, 1994

By Corrans I. J, Yan D. S

The CIP process for gold recovery has enjoyed widespread application in most gold-producing countries. The development of a mathematical model of the CIP process has value for use in process design, process optimisation, and process control. Mathematical model development through laboratory experimentation is an important step in the design and optimisation of the CIP process. For this purpose, data has been generated through small scale laboratory leaching and adsorption tests both in batch and continuous mode. This test program has been carried out on specific ores of various types prior to the application of the models to production CIP plants utilising these ores. The applicability of leaching models derived from batch experiments was tested in a continuous five stage CIP pilot plant. The models were then adapted to scale-up the batch to the small scale continuous operation.

Jan 1, 1991

The increasing global demand for rough materials forces almost every mine to look at the mechanisation in their processes. This will not onlyimprove performance but with safety issues becoming more and more prevalent, the need for the introduction of mechanisation technologies to mining applications is essential. Ongoing developments are occurring in almost every field, ranging from basic developments to specialised mining. Mechanical tunnelling and shaft sinking have set the standards regarding safety, profitability and environmental protection. Different machine types and working principles have been developed to suit the geological and hydrological requirements of tunnelling projects worldwide. Continuous activity in research and development leads to constant optimisation of tunnelling performance.

Jan 1, 2008

Copper refining electrolytes are maintained in the range 60-65¦C to ensure an efficient operation. The heat energy required to meet these temperatures has been traditionally derived from the electrical energy required for the electrolytic process and supplementary steam energy. In 1983, experiments were conducted at Copper Refineries Pty. Ltd. (CRL) to determine the effects of insulating the Tank House cells, and fully covering the cells. The results of these experiments showed conclusively that greatly reduced steam consumption would be required to maintain electrolyte temperatures. These positive results led to an Energy Conservation Programme for the Tank House, and this was implemented in 1984. A computerised cell cover monitoring system was developed, and is used to control cell coverage and fluid balance. The experimental work and the benefits obtained since implementation of the programme are discussed.

Jan 1, 1985