Modern Mining January 2016

COPPER

globally. Installing these units underground reduces the need to pump water to the surface for cooling; instead, upcast air is used to reject heat in underground cooling towers and cool air is blown down to the work face. To match the capacity of the 17-t LHDs, the crusher configuration will be different to the four jaw crushers at Lift I. Rather, Lift II will install two jaw-gyratory crushers – essentially gyratory crushers with much larger throats – capable of taking bigger lump sizes. With a 2 000 t/h capacity and multiple tipping points, these units will avoid any unproduc- tive queuing when being fed by the 17-t LHDs underground. There are also to be some significant improvements in the processing plant, accord- ing to Flotation Plant Project Manager Willie Laing. Most interesting among these is the project’s use of sorting as a means of pre-con- centrating ore and of improving the final quality of concentrates. Palabora intends installing optical ore-sorters to separate barren dolerite – comprising 10-12 % of run-of-mine feed – from copper-bearing material, a process made pos- sible by the distinct colour difference between these two rock types. In addition, said Laing, tank cell technology is to be introduced into the new flotation plant, with the aim of improving recoveries from 80 % to a targeted 88 % – delivering about 30 % cop- per; magnetite recoveries will also improve to 63-65 % iron in the final product. He said extensive tests at mineral research group Mintek, conducted with a specially installed 10 m 3 tank, showed the technology gave posi- tive results, especially with lower grades. Following the green light for Lift II’s imple- mentation, employment expectations have been understandably high in communities around the mine – which have had to be carefully managed by Palabora. According to Corporate Affairs Manager Hulisani Nemaxwi, the mine has leveraged the project’s employment impact by reaching agreements with contractors – where most of the new jobs have been gener- ated – to ensure at least 80 % of non-skilled and semi-skilled job opportunities will be filled by local residents. “We are also focused on upgrading skills of workers, as well as developing local small businesses to become reliable and sustainable providers of services – both to the mine and to other players in the local economy,” said Nemaxwi. “We have spent about R160 mil- lion over the past five years, and the results are encouraging.” As one of South Africa’s largest mining

development projects, Lift II must rank also as one which generates considerable and much- needed confidence in a mining sector under almost unprecedented global and local stresses.

A Murray & Roberts Cementation raise borer working underground at Palabora.

Retaining its focus on innova- tion, and basing its decisions on solid geological, min- ing and metallurgical data, Fouche emphasises that any good project still relies on its people. “Many of the people who

Unique geology Unlikemost of the world’s copper mines, which mine their copper from porphyry deposits, Palabora’s ore occurs in the carbonatite formation known as the Pal- abora Igneous Complex. The complex also hosts a range of other minerals such as phosphates, vermiculite, phlogopite, magnetite, nickel, gold, silver, platinum and palladium.

were involved in Lift I are now part of the Lift II project team, giving the project vital intellectual memory to ensure that we can apply our lessons learnt and imple- ment configuration changes,” he said. 

PALABORA OVER THE YEARS 1956 – Founded as Palabora Mining Company and began opencast mining 1996 – Construction begins on Lift I underground project 2002 – Production begins from Lift I block cave 2007 – Drilling starts on Lift II orebody 2011 – Business case study starts for Lift II project 2012 – Construction begins on Lift II twin decline to orebody 2014 – Feasibility study for Lift II completed 2015 – Shareholders approve final plan to proceed with Lift II project 2017 – First production expected from Lift II block cave

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January 2016  MODERN MINING  67