Scielo RSS <![CDATA[Journal of the Southern African Institute of Mining and Metallurgy]]> http://www.scielo.org.za/rss.php?pid=0038-223X20100007&lang=pt vol. 110 num. 7 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Traditions, transactions, and technology transfer</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700001&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Process design of the Phola coal preparation plant</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700002&lng=pt&nrm=iso&tlng=pt The 2 360 t/h two module Phola coal preparation plant represents a new era of large plant in the Witbank coalfield designed to extend its life to 2020 and beyond. The plant uses the optimum processing model for Witbank coals, receiving a feed coal size of -50 mm, wet screening it into coarse and small coal fractions 50 x 12 and 12 x 0.63 mm before processing them in parallel through two primary DM cyclone sections, in order to make a 27.5 MJ/kg export floats product. The sinks are processed through a common high density DM cyclone section to produce a 21.5-23 MJ/kg thermal coal middlings product. The plant design incorporates the largest size DMS equipment used to date in South African coal preparation plants, i.e. 1 150 mm large diameter pump fed DM cyclones and 4.2 m width banana screens. The fine coal is conventionally processed by spirals, whereas the raw coal slimes are filtered using automated plate and frame filter presses and added to either the middlings or discards depending on its quality. The paper describes the database, innovative design concepts, construction, and commissioning. <![CDATA[<b>The application of the AMIRA P754 metal accounting code in the coal industry</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700003&lng=pt&nrm=iso&tlng=pt The development of an accounting code for the metallurgical industry has been debated for many years. Following the series of tumultuous economic events in the nineties and earlier this century that have affected business, there was much need for legislation to be passed to minimize potential risk. One of the consequences to affect the mining industry was the enhancement of existing geological codes for reporting. In parallel the sponsors of AMIRA have taken the brave step to develop a generic code for metal accounting that embraces the full gamut of industry. In this paper the code will be reviewed in the context of metallurgical accounting as it applies to coal preparation. This paper provides the background for this development and an insight into the mechanism for the debate for the generation of this code. The key elements of the code as it applies to the coal industry are explained but most importantly the key opportunities are highlighted. <![CDATA[<b>Reduced maintenance costs resulting from the use of wear resistant materials</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700004&lng=pt&nrm=iso&tlng=pt The development of an accounting code for the metallurgical industry has been debated for many years. Following the series of tumultuous economic events in the nineties and earlier this century that have affected business, there was much need for legislation to be passed to minimize potential risk. One of the consequences to affect the mining industry was the enhancement of existing geological codes for reporting. In parallel the sponsors of AMIRA have taken the brave step to develop a generic code for metal accounting that embraces the full gamut of industry. In this paper the code will be reviewed in the context of metallurgical accounting as it applies to coal preparation. This paper provides the background for this development and an insight into the mechanism for the debate for the generation of this code. The key elements of the code as it applies to the coal industry are explained but most importantly the key opportunities are highlighted. <![CDATA[<b>Coal preparation research in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700005&lng=pt&nrm=iso&tlng=pt South Africa is reliant on coal for the generation of almost all the electricity used in the country, and several large industrial concerns such as Sasol are also coal based. Research relating to the mining, beneficiation and utilization of coal is important in order to ensure the optimal exploitation and use of coal within the country. The Fuel Research Institute (FRI) of South Africa was established in 1930 to investigate all aspects of coal beneficiation and utilization in South Africa. The FRI went on to conduct world-class research, and in 1957 a pilot coal preparation plant was constructed in Pretoria to enable large-scale practical experimentation. The pilot plant played a pivotal role in the establishment of South Africa's low ash coal export project. Political and economic factors contributed to the eventual closure of the FRI and South Africa experienced a period of about 10 years between 1990 and 1999 during which very little public coal preparation research was done. This changed for the better towards the end of 1999 when Coaltech 2020, a collaborative research program was established. Participants included the CSIR, universities, the government and the major coal producers. Coal preparation research conducted under Coaltech thus far include dewatering and drying of fine coal, size classification of ultra-fine coal and dense-medium fine coal beneficiation. Currently, the Coaltech focus is on the beneficiation of low-grade coal reserves and is investigating existing as well as new techniques that can be utilized to provide cost-effective beneficiation of low-grade raw coals and reject coals. <![CDATA[<b>Addressing the envelope</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700006&lng=pt&nrm=iso&tlng=pt Most coal plants must run under conditions of varying feed conditions or are asked to produce qualities different from that used in the design. This can cause overloaded conditions as the 'bottlenecks' within the plant, depending on plant operation or as the feed changes. During plant design, geological information can be used to determine washability envelopes and blends that may be expected. Historical data can also be used to develop a size distribution envelope as well as to assign reasonable models for each of the unit processes. In operation, a plant can be sampled to determine changes and to refine process models. The information obtained can then be used in an accurate simulation to define how the plant can deal with the changing environment. This paper uses Limn:The Flowsheet Processor to simulate the coal plant in detail and will produce an accurate model, in terms of equipment sizing as well as water, medium, and solids balance, for each change in feed condition. It will show examples of running the simulation through complete density and size ranges and will determine the equipment required to address each part of the performance envelope. <![CDATA[<b>Dual energy X-ray transmission sorting of coal</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700007&lng=pt&nrm=iso&tlng=pt Dual energy X-ray transmission (DE-XRT) sorting is a recent development in the range of sensor-based sorting technologies available today. DE-XRT is particularly suitable for dry coarse coal beneficiation in the size range -120 mm +12 mm. In this paper, we describe the technology and show the results of a number of test runs conducted on different types of coal from the USA and South Africa. The results have shown that DE-XRT is an effective technology not only for deshaling of coal and removing pyritic sulphur but also for separating coal and torbanite. The use of dry deshaling methods will be more important as water availability becomes a greater concern. DE-XRT is one such technology which will be incorporated in future dry coal processing plants. <![CDATA[<b>The socio-economic aspects of mine closure and sustainable development: Literature overview and lessons for the socio-economic aspects of closure - Report 1</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700008&lng=pt&nrm=iso&tlng=pt Dual energy X-ray transmission (DE-XRT) sorting is a recent development in the range of sensor-based sorting technologies available today. DE-XRT is particularly suitable for dry coarse coal beneficiation in the size range -120 mm +12 mm. In this paper, we describe the technology and show the results of a number of test runs conducted on different types of coal from the USA and South Africa. The results have shown that DE-XRT is an effective technology not only for deshaling of coal and removing pyritic sulphur but also for separating coal and torbanite. The use of dry deshaling methods will be more important as water availability becomes a greater concern. DE-XRT is one such technology which will be incorporated in future dry coal processing plants. <![CDATA[<b>The socio-economic aspects of mine closure and sustainable development - guideline for the socio-economic aspects of closure: Report 2</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2010000700009&lng=pt&nrm=iso&tlng=pt Dual energy X-ray transmission (DE-XRT) sorting is a recent development in the range of sensor-based sorting technologies available today. DE-XRT is particularly suitable for dry coarse coal beneficiation in the size range -120 mm +12 mm. In this paper, we describe the technology and show the results of a number of test runs conducted on different types of coal from the USA and South Africa. The results have shown that DE-XRT is an effective technology not only for deshaling of coal and removing pyritic sulphur but also for separating coal and torbanite. The use of dry deshaling methods will be more important as water availability becomes a greater concern. DE-XRT is one such technology which will be incorporated in future dry coal processing plants.