Name: Two Rivers mine.
Location: The operation is situated on the farm Dwarsrivier on the southern part of the eastern limb of the Bushveld Complex, an estimated 35 km south-west of Burgersfort, in South Africa’s Mpumalanga province.
Controlling Company: The Two Rivers operation is a joint venture (JV) between African Rainbow Minerals (ARM) and Impala Platinum Holdings (Implats). The mine is managed by ARM.
An agreement has been reached to incorporate portions 4, 5 and 6 of the adjoining Kalkfontein farm and portions of the Tweefontein farm held by Implats, into the Two Rivers mining area. As a result, Implats’ interest in Two Rivers has increased from 45% to 49%, and ARM’s has decreased from 55% to 51%.
Brief History: Platinum was first discovered in the Two Rivers area by renowned explorer Hans Merensky on the nearby farm Maandagshoek (now Modikwa Platinum) in the 1920s. During 2001, Assmang elected to sell its platinum interests in the Dwarsrivier chrome mine. Two Rivers Platinum, the incorporated JV between Avmin and Implats, secured the platinum rights in December 2001. Subsequent corporate activity, involving Avmin, ARM and Harmony, resulted in the transfer of Avmin’s share in Two Rivers to a new, empowered platinum entity, ARM Platinum, a division of ARM. The JV partners began development of the Two Rivers project in June 2005. The concentrator plant was commissioned early in the 2007 financial year, with the mine successfully making the transition from project to operation in 2008.
Brief Description: Two Rivers holds a contiguous old-order mining right over 2 140 ha on a portion of the Dwarsrivier farm. The conversion to a new-order mining right was executed during 2013. The operation comprises two on-reef decline shafts and a concentrator plant and has a life-of-mine offtake agreement with Impala Refining Services (IRS).
Geology/Mineralisation: The Merensky and underlying upper group two (UG2) reefs occur on the Two Rivers property, but only the UG2 is currently mined. The UG2 outcrops in the Klein Dwarsrivier valley over a 75 km north-south strike length and dips to the west at about 7° to 10°. The vertical separation between the Merensky and UG2 reefs is about 140 m. Owing to the extreme topography, the Merensky reef outcrops further up the mountain slope and also results in the UG2 occurring at a depth of 935 m below surface on the western boundary.
Three distinct reef types have been defined for the UG2 reef at Two Rivers, the normal reef, with a thick main chromitite layer; a split reef characterised by an internal pyroxenite/norite lens within the main chromitite layer; and a multiple split reef, with numerous pyroxenite/norite lenses occurring within the main chromitite layer.
Reserves: Total mineral reserves as at June 30, 2014, were estimated at 30.5-million tonnes grading 3.06 g/t platinum, palladium, rhodium and gold (4E) and 3.69 g/t platinum, palladium, rhodium, iridium, ruthenium and gold (6E).
Resources: Total mineral resources as at June 30, 2014, were estimated at 105.4-million tonnes grading 3.34 g/t 4E and 3.86 g/t 6E.
Products: 4E and 6E.
Mining Method: Underground. The UG2 orebody is accessed using two decline shaft systems situated 3 km apart – the Main decline and the North decline. Mining operations are fully mechanised and the bord and pillar mining method is used where stoping widths average about 1.8 m. A mining section consists of eight 12 m rooms, with pillar sizes increasing with depth below surface. The larger portion of the mineral reserves (75%) is located in the Main decline section.
Major Infrastructure and Equipment: Two Rivers has a concentrator plant on site, where initial processing is done. It comprises a standard MF2 design as generally used in the industry. Concentrate is transported over land to Implats’ Mineral Processes, in Rustenburg, where further processing takes place in terms of an agreement with IRS.
Prospects: Subsequent to the half-year ended December 31, 2014, transactions to transfer the mineral rights on the Kalkfontein, Buffelshoek and Tweefontein farms from Implats to Two Rivers, in return for an additional 4% stake in Two Rivers and a royalty agreement, have become unconditional. These transactions have increased Implats’ shareholding in Two Rivers to 49% and will enable Two Rivers to maintain production above 150 000 oz of platinum in concentrate in the medium term.
Contact Person: Group corporate relations manager Alice Lourens.
Contact Details:
Implats,
tel +27 11 731 9000,
fax: +27 11 731 9254,
email Alice.Lourens@implats.co.za, and
website http://www.implats.co.za.