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The 98th Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Gold Room, Transvaal Automobile Club, 60 5th Street, Lower Houghton, Johannesburg on Wednesday, 16th August, 1995. Obituaries The President announced the death, during the year, of the following members: Honorary Life Fellows R.C.J. Goode, F.G. Hill Life Fellows R.S. Cooke, J. W. V. Mortleman Fellows S. Craib, R.R. Hendry, T.J.B. Jones

Jan 1, 1995

The 99th Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Gold Room, Transvaal Automobile Club, 60 5th Street, Lower Houghton, Johannesburg on Wednesday, 14th August, 1996. Obituaries The President announced the death, during the year, of the following members: Life Fellows H.L. Munro, H.S. Simpson, P.L. Ward Fellows I.M. Hossy, A.E. O'Meara Retired Fellows E.A. Arvidson, R.F. Bourne, F. Hawke, W. Lloyd, J.M. Meyer Members J. Allen, P.A. Boardman, L.M. Jacobs, G.F. Marx, G.D. Perry, R.W. Spraggs Retired Member M. Milner Associate I. Pieterse. In memory of the deceased and in sympathy with the bereaved, all rose and observed a moment of silence.

Jan 1, 1996

The 89th Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on 20th August, 1986. Mr. H. E. James (President) was in the chair and declared the meeting open at 16hoo. Obituaries President: It is my sad duty to announce the deaths of the following members of this Institute: Life Fellow D.L. Carson; Retired Fellows T.K. Adams, G.E. Carlyon, N.M. Holford, D.E. Maclver, C.J. Morgan; Fellows S.K. de Kock, R.R. Porter, Dr G.J. Rees; and Associate Sir Lindesay Clark. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, please rise and observe a moment of silence. Minutes President: The 88th Annual General Meeting of the Institute was held on Wednesday, 14th August, 1985, and the minutes were published in the September 1985 issue of the Journal. The minutes were confirmed.

Jan 1, 1986

The 91st Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on 17th August, 1988. Mr B.c. Alberts (President) was in the Chair, and declared the meeting open at 16hOO. Obituaries The President announced the deaths of the following members of the Institute:

Jan 1, 1988

The 92nd Annual General Meeting of The South African Institute of Mining and Metallurgy was held on Wednesday, 16th August, 1989, at Kelvin House. Mr C.E. Fivaz (President) was in the Chair, and declared the meeting open at 16:05. Obituaries The President announced the deaths of the following members of the Institute:

Jan 1, 1989

The 90th Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on 19th August, 1987. Dr H. Wagner (President) was in the Chair and declared the meeting open at 16h00. Obituaries The President read out the names of the departed Members as follows: N.M. Airey, F.J. Kisbey-Green, Dr R.A. Pelletier, C.B. Anderson, A.R. Cator, J. van Heerden, P.J. Burman, C.C. Crosson, M. Livingstone¬Blevins, S.T. Firman, V.E. Kisbey-Green, and A.L. Corna. All stood and observed a moment of silence as a mark of respect. Minutes The minutes of the 89th Meeting of the SAIMM, which was held on 20th of August, 1986, were confirmed.

Jan 1, 1987

The 93rd Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Highveld Room of the Carlton Hotel in Johannesburg on Wednesday, 15th August, 1990. Obituaries The President announced the deaths of the following Members of the Institute:

Jan 1, 1990

The 94th Annual General Meeting of The South Mrican Institute of Mining and metallurgy was held in the Gold Room of the Transvaal Automobile Club in Johannesburg on Wednesday, 14th August, 1991. Obituaries The President announced the deaths of the following members of the Institute: Honorary Life Fellow and Past President

Jan 1, 1991

The 95th Annual General Meeting of the South African Institute of Mining and Metallurgy was held in the Gold Room of the Transvaal Automobile Club in Johannesburg on Wednesday, 12th August, 1992.

Jan 1, 1992

The 96th Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Gold Room of the Transvaal Automobile Club in Johannesburg on Wednesday, 11th August, 1993. OBITUARIES The President announced the deaths of the following members of the Institute during the past year. Life Fellow E.F. Laschinger. Other Members R.K. Boright, J.S. Jacobi, R.D. Power, J.H. Cannon, C.J. du Plooy, L.B. Mcrae, C.P. Rossouw, A.L. Sillars, A.W. Heugh, R.K. Briggs, P.J. Stark, and C.S. Stott. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, all rose and observed a moment of silence.

Jan 1, 1993

A Special General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on Wednesday, 20th August, 1986. Mr H.E. James (President) was in the chair and declared the meeting open at 15h45. Background The Chairman explained that the meeting had been called to consider a number of amendments to the SAIMM constitution. The proposed changes had been set out in detail in a document that had been mailed to all members on 4th July, 1986. He then briefly reviewed the background to the proposals, which is outlined in the Preface to the Annual Report (page 357 of this issue). The Chairman added that the Executive Committee of SACPE at its meeting on the 8th August, 1986, had resolved that the proposed amendments to the SAIMM constitution did comply with the requirements of Regulation RI525 dated 17th July, 1981, regarding the recognition by SACPE of a society as a Professional Engineering Institute.

Jan 1, 1986

Advanced process and equipment analytics have been around for a while. However, with accessible IT infrastructure and site maturity, it is possible to analyse, monitor, and control processing plants and equipment easily. These various disparate systems provide different reports requiring the involvement of various personnel and attention to different reporting platforms. For efficient harnessing of the systems? capabilities, as well as effective improvement and monitoring of process and equipment, a single point of entry is required. A process and equipment optimization solution was required at a concentrator in South Africa, focussing on the product stream of platinum group metal (PGM) concentrate from the UG2 Reef. The investigation of data to identify strategies for optimization was required to allow visibility into plant operations to guide operators, an easier method to identify process loop problems, identification of imminent equipment failures, and advanced process control to optimize throughput and stability. A collaborative effort between the client and General Electric Intelligent Platforms (GEIP) investigated data-driven solutions to each of the problems. With the focus on process optimization and asset monitoring, as well as equipment monitoring, a combination of approaches was utilized to address the various problem areas that were identified. Each was implemented separately in the control layer of the plant IT infrastructure. The integration was done in a centralized web-based reporting tool that integrated the detailed results from the various solutions. On the process control side, monitoring of control loops was included by calculating performance statistics that were reported daily to identify sub-optimally performing control loops and indicating potential problems. The advanced process control solution for this site includes a surge tank controller, stabilizing flow through the flotation banks, and preventing the surge tank from overflowing or running empty. Equipment monitoring was investigated, for preventative maintenance, by making use of statistical data models to indicate imminent equipment failure. These predicted alarm events included the cause for failure, drilling down, and allowing focus on a specific variable for preventative action. The results included a more stable flow through the mill, with fewer stoppages due to surge tank overflows or running empty. The causes for process drift could be identified and operators could react early. Alarms warning of equipment failure 2½ and 4 months in advance were identified in an offline analysis.

Jan 1, 2012

Bougainville Copper Limited (BCL) operates a 50 Mtpy copper/gold/silver mine and concentrator on Bougainville Island, Papua New Guinea. BCL has installed an in-house developed data logging and supervisory process control system using a DEC PDP 11/73 mini-computer in the mill and has recently installed a similar system in the crushing plant. Together with the central DEC VAX 11/780 computer, they form part of a high speed, fibre optic, local area network in the concentrator. The in-house developed software, known as BIAS (Bougainville Copper Information and Automation System), was developed as a low cost option to interface to a number of different existing plant input/output systems while providing the capability to make maximum use of computer networking facilities. The package includes the more usual control system colour displays and data logging features, but also makes provision for two novel features: (a) Any user connected to the computer network can access the system displays. This allows metallurgists and management to monitor (but not control) plant operation from their offices. (b) Specialized application programs for performing advisory and supervisory control, dynamic simulation, and data analysis are easily incorporated into the system. The mill process system currently runs rougher/scavenger flotation stabilizing control and general data logging. The crushing plant system currently performs data logging only; however it will soon be augmented with the facility to run dynamic crushing plant simulations. Future developments will concentrate on making greater use of the detailed information available from the mine's fully automatic truck dispatch system which runs on a VAX 11/780 computer. Milling process control will be expanded to examine possible economic control of the operation of regrind and cleaner flotation circuits. An advisory water management system to optimize water supply within powerhouse generating capacity constraint will also be investigated.

Jan 1, 1987

"Chairman: Dr R. E. ROBINSON Rapporteur: Dr R. P. COLBORNPapers:The simulation of crushing plants by W. J. WhitenSimulation of multi-component flotation plants by B. K. Loveday and G. R. MarchantComputer control of flotation at the Ecstall concentrator by M. P. Amsden C. Chapman and M. G. ReadingModel for the design and control of flotation plants by R. P. KingIn presenting his paper Dr W. J. Whiten outlined the basic concepts on which the control model was based and emphasized the fact that empirical models based as much as possible on theory were used to simulate each unit of the crushing plant. The final parameters of each model were computed using data collected from the plant. Unfortunately, the system did not permit accurate extrapolation but was successful when operating in the region from which the parameters were calculated.He concluded from the results of the test work that the crusher amperage was a critical parameter and that the utilization of the model gave a 15 per cent increase in the plant output. This was because the model predicted that a marginally fine grind would provide a significant increase in throughput. Dr Whiten elaborated on what constituted the multiple spline regression, explaining that it was a least-squares curve-fitting technique in one or more dimensions, where the calculation of coefficients in analytic expressions was replaced by the calculation of typical points on a very smooth curve called a spline function. The emphasis was placed on the shape and value of the curve or curves instead of on the coefficients as in analytic regression. A spline function was the line drawn between all points constituting the data set.Dr B. K. Loveday commented that the simulation was unusual in that the optimum throughput was considered to be the maximum throughput, which, surely, was limited by the crusher size. He also emphasized the importance of the interaction between both crushing and grinding circuits and added that in practice the optimum operating conditions were inter-dependent. Dr Whiten replied that in the case of the plant under consideration, the crushing process was not, in fact, the limiting operation.Mr C. E. Clifford indicated that the model was being used to simulate a number of crushing and grinding circuits at Mount Isa Mines. He reported that the model simulated the circuit satisfactorily for primary and secondary gap settings of 0,625 in. to 0,375 in., but that adjustment had to be made to the model parameters for gap settings of 0,250 in. to 0,125 in.In reply to a question from Dr D. M. Hawkins, Dr Whiten said that he preferred to use low-order splines with smaller segments rather than high-order spline functions with large segments."

Jan 1, 2014

By M. Jacobs

Keywords: Smelting, converting, sulphide, sulphide smelting, platinum, platinum group metals, PGM, base metals, nickel, copper, matte, slag, furnace, electric furnace, Söderberg, electrode, granulation, converter, flash drier, sulphuric acid, acid plant, Ausmelt, Sirosmelt, pyrometallurgy, metallurgy, Anglo Platinum, South Africa Waterval Smelter complex is situated in Rustenburg, in South Africa?s North West Province. The smelter objective is to process wet concentrate to produce crushed, slow-cooled, sulphur-deficient nickel-copper matte rich in platinum group metals (PGMs), gold, and base metals for despatch to the Magnetic Concentration Plant at the Base Metals Refinery. Throughout its history, the smelter complex has been continuously upgraded in line with increasing production demand, changing feeds, environmental initiatives, and advances in available technology. The smelter receives filter cake and slurry from Anglo Platinum concentrators and joint ventures. Wet concentrate is fed through a flash drying process utilising coal-fired, fluidised bed hot-gas generators, to produce dry feed material for the electric furnaces and slag-cleaning furnace. For primary smelting, two electric furnaces are used, each with a rated capacity of 34MW. Furnace matte, containing the bulk of the base metal sulphides and PGMs, is tapped periodically into refractory-lined ladles and granulated using high-pressure water jets, then dried through electrically powered pneumo-driers to become the main feed to the Anglo platinum Converting Process (ACP). Slag is tapped semi-continuously, granulated, and treated through the slag mill. The ACP treats the combined matte output of Waterval, Polokwane, and Mortimer smelters. It is a top-blown furnace, with furnace matte, air, and oxygen being injected into the converter via a lance submerged in the slag. Converter matte is tapped and bottom cast into moulds, slow-cooled, crushed, and despatched to the refineries. Slag is granulated and dried for recycling to the slag-cleaning furnace. ACP slag is fed to the slag-cleaning furnace along with a reductant and a sulphur source. Slag-cleaning-furnace matte is granulated for processing by the ACP, while slag is granulated and processed in the slag mill. The slag mill and flotation circuit treats granulated slag from the electric furnaces and slag-cleaning furnace to recover entrained matte containing valuable PGMs and base metal sulphides.

Jan 1, 2006

By P. K. Van Manen

Anglo Platinum's Polokwane Smelter is situated outside Polokwane, in the Limpopo Province of South Africa. Wet concentrate is received from various concentrators along the Eastern Bushveld Complex. Approximately 60% of the total concentrate received is from UG2 Reef, and 40% is from Merensky Reef. The concentrate is dried in two flash dryers, and smelted in a single 168 MVA furnace. A PGM-rich nickel-copper matte is cast, crushed and transported to Rustenburg for converting. The plant was commissioned in March 2003. The wet concentrate, containing 12-18% moisture, is weighed, sampled by one of two auger samplers, and off-loaded into a concentrate shed, either directly through a grizzly into a hopper, or onto the floor. From the shed the concentrate is conveyed to 12 concrete silos. Each of the two identical flash dryers can be fed from six silos. From the flash dryers concentrate is transported pneumatically to a 3 000-ton dry concentrate storage silo. The flash dryers are rated at a nominal 66 tph of dry concentrate at 14% moisture, while the furnace can smelt 90 tph of dry concentrate. Therefore both flash dryers are required to operate when the furnace runs at design throughput. Each flash dryer consists of a hot gas generator (HGG), a disintegrator and drying column, and a section for gas/solids separation. In the HGG, gas heated up to 700° C is produced from the combustion of coal peas in a fluidized sand bed. The hot gas and wet concentrate are introduced to the disintegrator at the bottom of the drying column. The disintegrator breaks up any lumps of concentrate, and throws the concentrate up into the drying column, where it travels co-currently with the hot gas. A fan draws the hot gas from the drying column and through the gas/solids separation section, which consists of three primary cyclones, a multiclone and a high-temperature bag house. The dry concentrate reports to a 450-ton dry concentrate storage bin. A portion of dry concentrate is recycled to the wet concentrate feed in a paddle mixer, so that concentrate that is too wet does not enter the disintegrator. The drying column outlet temperature is controlled at 120° C. Coal is received by road, screened for oversize and conveyed to a 400-ton concrete silo. From here it is pneumatically conveyed to a small feed bin at each of the HGG' s. The optimization work consists of process control improvements relating to the HGG outlet temperature, to control the drying column temperature during the ramp-up of the HGG outlet temperature and bag filters. Furthermore a heat balance is used to evaluate options to increase the instantaneous drying capacity of the existing equipment. The coal consumption derived from the heat balance is compared with the actual coal consumption. The purpose of the optimization work is to achieve an operating schedule for the flash dryers such that they operate simultaneously for as short time as possible. Most of the time one flash dryer should operate, allowing maintenance to be done on the other flash dryer, while drawing down the dry concentrate stock. Keywords: Anglo Platinum, Polokwane Smelter, pyrometallurgy, metallurgy, platinum, platinum group metals (PGM), base metals, flash drying, fluidized bed.

Jan 1, 2006

By J. Ndlovu, R. Hundermark

Keywords: Anglo Platinum, Polokwane Smelter, pyrometallurgy, metallurgy, platinum, platinum group metals, PGM, base metals, nickel, copper, sulphide smelting, electric furnace, Söderberg, electrode, matte, slag, flash drying, matte casting, crushing, granulation Anglo Platinum?s Polokwane Smelter is situated outside Polokwane, in the Limpopo Province of South Africa. Wet concentrate is received from various concentrators along the Eastern Bushveld Complex, with 60% of the total concentrate received being from UG2 reef and 40% from Merensky reef. The concentrate grade differs from 35 g/t to 110 g/t, and from this a PGM-rich nickel-copper matte is produced. The furnace matte produced is sent to the ACP converter in Rustenburg. The Anglo Platinum concentrators, from which concentrate is received, are Lebowa, Potgietersrus, Amandelbult, and Union, as well as the joint venture Modikwa. The concentrate is fed to two flash dryers that utilise coal-fired, fluidized-bed hot-gas generators to produce the hot gas that will drive off the moisture, leaving a fine bone-dry concentrate to feed to the furnace. The dry concentrate is pneumatically transferred to a storage silo before being transferred to the feed bins situated above the furnace. Lime, if required as a flux, may be transferred separately to the furnace feed bin by a pneumatic system. The concentrate and lime is fed from the feed bins onto airslides and into the furnace. The feed rate is automatically controlled, and the system is set up to optimize the power to feed ratio. The electric furnace is nominally rated at 68 MW and the power is transferred into the furnace using six 1.6 m diameter Söderberg electrodes. Concentrate is melted by energy generated when electric current passes through the electrodes and resistive slag layer. On melting, two immiscible phases form: slag and matte. Furnace matte, containing the bulk of the base metal sulphides and PGMs, is denser than slag and collects naturally at the bottom of the furnace. The furnace is constructed of a combination of refractory brick and water-cooled copper coolers. The furnace sidewalls and hearth are cooled by air drawn through the area by cooling fans. The hearth and matte zone are constructed from refractory bricks. The copper coolers reside only in the slag zone of the furnace along the entire perimeter of the furnace. One staggered row of plate coolers is installed above the waffle coolers along the perimeter of the furnace. Matte is tapped periodically through one of the two matte tapholes into 35-ton refractory-lined ladles, and cast into matte ingots on a casting machine. The cooled matte is discharged onto a concrete slab for cooling and then transferred by front-end loaders to the crushing plant. The matte is first crushed in a jaw crusher and then a Rhodax cone crusher to a size of 2 mm before it is loaded into tankers and sent to the ACP. The low-grade slag is tapped from the furnace through a water-cooled copper insert into a short water-cooled copper ?hot launder? which discharges into a granulation cold launder. The granulated slag slurry flows to three rake classifiers, from which the coarse slag is discharged onto a conveyor to dewatering silos. The dewatered slag from the silos is dumped. The water overflow from the classifiers reports to two thickeners where the water is clarified, and the thickener underflow is returned to the rake classifiers. The smelter is a zero-effluent plant and all the water from the slag silos where the slag is dewatered, as well as the storm water, is pumped to the process water dam from where it is pumped back into the plant for process water use. The off-gas from the furnace is drawn through a forced draught cooler and into a high temperature baghouse. The dust collected in the baghouse is pneumatically transferred into bins above the furnace and is fed via the concentrate airslides. The cleaned off-gas is then vented through the main stack.

Jan 1, 2006

By E. J. McLean

Gold mineralisation at Bendigo is exclusively associated with quartz reefs, commonly found within or near anticlinal fold hinges. The gold is typically coarse grained (0.5 mm to 5 mm), free milling and displays a complex, nuggetty distribution within the veins. This ore is highly amenable to gravity recovery processes. As the Bendigo operation is not permitted to treat whole ore by a cyanide leach/CIL circuit, the flow sheet is more complex than conventional gold recovery circuits. Primary gold recovery is from a gravity circuit closing the grinding circuit to a bulk gravity concentrate and from a flotation circuit treating cyclone overflow to a bulk float concentrate. The plant capacity is relatively low by current gold industry standards at 600 000 tpa. Re-establishing gold production at Bendigo has presented several challenging, and sometimes competing, issues in process design and operation. The mine, process plant, associated services and infrastructure are at Kangaroo Flat, a low density, semi-rural zone in the southern urbanisation of the Bendigo metropolitan area. One of the main processing challenges during the design was the competing comminution requirement to avoid over-grinding, which would flatten or smear the characteristic nugget gold and hinder effective gravity gold recovery, whilst also providing sufficiently well liberated particles that would respond well to flotation. Important, non-metallurgical challenges were to minimise impacts on the local community from noise, dust, air emissions, visual impact, water egress and off-site traffic.

Jan 1, 2007

This paper presents the development of a regrind facility design at BHP Billiton's Leinster Nickel Operations (LNO) in Western Australia. The recovery opportunity was identified from an analysis of plant operating data together with scanning electron microscope (SEM) measurements on relevant tailings streams from LNO. A laboratory procedure was developed to determine the potential recovery improvement of installing a regrind facility at LNO. The last step in formulating the process flow sheet and defining the process design criteria was to construct and operate a pilot plant, which incorporated four banks of flotation cells and an Xstrata M20 Isa Mill. Pilot plant on/off trials were used to define the expected metallurgical benefit. A prefeasibility engineering design and cost estimate was completed. Following a successful internal business evaluation, a feasibility study is currently underway.

Jan 1, 2007

By G. M. Cresswell

The 2 360 t/h two module Phola coal preparation plant represents anew 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 x12 and 12 x0.63 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.

Jan 1, 2010