Anglo American Platinum Limited |
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Smelters
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Anglo American Platinum operates three smelting complexes, namely the Mortimer, Waterval and Polokwane smelters. Concentrate received from the concentrators operated by the Company, joint-venture partners and third parties is smelted at the smelters, resulting in the production of furnace matte. The matte is then treated using the Anglo American Platinum converting process (ACP), which is carried out at the Waterval Smelter complex in Rustenburg. The converter matte tapped from the converter is then slow-cooled, crushed and dispatched to our Rustenburg Base Metals Refiners for further processing.
During 2011, scheduled furnace maintenance was carried out on the No 1 furnace and the slag-cleaning furnace at Waterval Smelter, on the Polokwane furnace, and on the ACP. It was noted that the Polokwane Smelter matte end-wall showed significantly reduced wear following the design modifications made in 2010. A complete sidewall rebuild was done on the No 1 furnace at Waterval Smelter, while a major redesign to the slag granulation circuit was successfully executed on the slag-cleaning furnace, significantly improving the operability and safety aspects of slag-tapping activities.
In the third quarter of the year the capacity of the Mortimer Smelter furnace and its auxiliary equipment was upgraded, from 180 ktpa to 360 ktpa concentrate, and the plant was successfully commissioned in September 2011, with continued ramp-up planned for 2012.
Operational stability at the ACP and the availability of the acid plant ensured that sulphur dioxide emissions from the Waterval Smelter complex remained within prescribed limits. Environmental compliance was also achieved at the Polokwane and the Mortimer smelters.
SAFETY
Overall, our smelting operations achieved a year-on-year reduction in total injuries of 5%. Mortimer Smelter continued with its excellent safety performance and maintained its LTI-free record for a second year. The total injury-frequency rate (TIFR) was 1.6 against an industry benchmark of 2.0, but the lost-time injury-frequency rate (LTIFR) was 0.78.
On the journey towards zero harm, the smelters have aligned all their operations with Anglo American plc's safety, health and environment strategy.
PRODUCTION
All smelting operations performed exceptionally well, exceeding the business plan on smelted concentrate tonnes by 3%. Polokwane Smelter achieved its highest recorded number of annual tonnes concentrate smelted since being commissioned.
Asset-optimisation initiatives improved furnace reliability and operating efficiency during the year, and total concentrate tonnes smelted in 2011 increased by 12% over those of the previous year to 1.22 million tonnes. The excess ACP converter slag stockpile was treated at the slag mill plant, resulting in the substantial recovery of precious metals and a significant release of stock that reduced the total inventory by a further 7% within the smelters. This was done to mitigate the effects of the ongoing deferment of slag-cleaning furnace No 2.
Platinum ounces in converter matte produced decreased by 3% to 2.50 million ounces owing to lower grades, although the mass of furnace matte treated by the plant increased by 9%.
COSTS
The smelter cash operating costs (including toll smelting costs) increased by 11% mainly as a result of the increased volumes treated, but were still 4% below business plan. This was achieved mainly because of improved efficiencies and reduced maintenance costs. The unit cash cost per tonne of new concentrate smelted decreased by 1% year-on-year, as a result of higher volumes treated and cost savings delivered through the asset-optimisation programme. The unit cash cost per 4E ounce dispatched increased by 14% to R459, largely as the result of lower grades and higher volumes treated.
CAPITAL EXPENDITURE
A total of R823 million was spent on capital for the year (against R576 million in 2010). Of this amount, R520 million was spent on project capital that included the expansion project at Mortimer Smelter (R421 million) and the deferment costs on slag-cleaning furnace No 2 at Waterval Smelter (R58.4 million).
Stay-in-business capital of R303 million was spent mainly on the replacement of the sidewalls of furnace No 1 (R42.6 million), on a spare hearth for the slag-cleaning furnace (R12.5 million) and on the redesign of the granulation box (R15 million) at Waterval Smelter. Other smaller projects included a transformer replacement (R18.7 million) and the installation of a furnace matte storage silo (R12.3 million) at Mortimer Smelter.
PROJECTS
Slag-cleaning furnace No 2
The slag-cleaning furnace No 2 project involves the installation of a second slag-cleaning furnace at Waterval Smelter in Rustenburg for treatment of ACP converter slag arisings owing to the fact that arisings produced exceed the current slag-cleaning furnace (SCF No1) capacity.
Owing to the 2008/9 global economic conditions, capital expenditure was deferred on the second slag-cleaning furnace. Aligned with current production planning, the implementation of the project is required to meet planned output of ACP converter slag. The project feasibility was restated during the fourth quarter of 2011 with Board approval set for April 2012. The planned first-tap date is now forecast for the fourth quarter of 2014.
Mortimer furnace upgrade
The project is a brownfield upgrade on the existing Mortimer Smelter site and is necessary in order to mitigate risks to installed smelting capacity and to increase smelting capacity in line with the forecast concentrate arisings.
The furnace upgrade was done in two phases, the first (Phase 1) having taken place during the second quarter of 2008 entailed a furnace hearth rebuild and the second phase included increasing the existing 6-in-line furnace power from the current 19 MW to a maximum of 38 MW.
The Mortimer Smelter furnace upgrade was completed in 2011, with the first matte tap having taken place on 7 September 2011.
OUTLOOK
The smelting operations are expected to further reduce unplanned furnace downtime, capital inefficiencies and unit costs through their asset-optimisation and continuous-improvement initiatives. In order to process higher matte fall concentrates, numerous initiatives to prevent bottlenecks will be carried out at the matte-handling facility of the Polokwane furnace, the Waterval Smelter slag-milling plant and the ACP facilities.
