UPDATE 1-Kumba to spend $1.15 bln on new iron ore mine

(Adds share price, CEO, details)

JOHANNESBURG, July 31 (Reuters) - Kumba Iron Ore Ltd (KIOJ.J), Africa's biggest producer of the steel making ingredient, will invest 8.5 billion rand ($1.15 billion) in a new mine set to start production in the first half of 2012.

Kumba said on Thursday its new Sishen South mine, which is in South Africa's Northern Cape province, will ramp up to full capacity of 9 million tonnes per year in 2013.

The mine will help push Kumba's total output past the 50 million tonne mark, the company, which is a unit of Anglo American Plc (AAL.L), added in a statement.

Shares in Kumba rose 3.35 percent to 262.50 rand, outperforming a 1.39 percent rise on South Africa's blue-chip Top-40 index .JTOPI.

It will have in excess of 20 years life, with the ore being shipped for export.

Chris Griffith, chief executive of Kumba, said the project pipeline remained robust, with a potential to deliver 70 million tonnes a year by 2015.

Kumba also secured commitment from state-owned power firm Eskom [ESCJ.UL] to supply electricity to the mine.

Mines in South Africa have been operating below full power since outages forced five days of shutdowns in late January, driving up precious metals prices and raising fears of job losses and slower growth.

Kumba also said it had won additional rail capacity for the export-bound ore after negotiations with logistics group Transnet [TRAN.UL].

Kumba has a target to boost output to 38 million tonnes this year, and has the potential to expand it to 70 million tonnes by 2015, which would make it the world's fourth-largest producer of lump iron ore.

Kumba has said world crude steel production was rising, fuelled by demand from China, and that it planned to lift exports to that country to 50 percent of its output from 35 percent once it has completed a number of expansions and new projects. (Reporting by James Macharia, editing by Will Waterman)