Anglo American's Chief Executive Cynthia Carroll stepped down on Friday, after more than five years at the helm but also after months of pressure from some shareholders over the share performance and the miner's continued dependence on troubled South Africa.

A geologist by training, Carroll became the first non-South African, the first woman and the first outsider to take the top job at Anglo when she became CEO in 2007.

She said in a statement she felt the time was right to hand over to a successor as she entered her seventh year at the helm.

Her departure was not unexpected.

Recent labor woes - compounded by nagging concerns over its Minas Rio iron ore project in Brazil and operational trouble in Chilean copper - have revived long-standing worries among some investors over Anglo's exposure to Southern Africa, the success of its acquisitions and, ultimately, a share price that has lagged peers.

Despite billions in cost cuts and efforts to streamline what was still in 2007 a sprawling consortium, analysts at Macquarie said this week that on a U.S. dollar market capitalization basis, Anglo has lost one-third of its value since Carroll became CEO. It is now worth some $25 billion less.

The rest of the peer group are worth at least the same as they were at the start of 2007, when she took over.

Violent strikes and labor troubles across the South African mining sector spread to Anglo American Platinum , the world's top producer of the precious metal, last month, just before the end of the current reporting period.

Weeks later, they hit Anglo's Kumba iron ore unit, which alone accounted for almost half the group's operating profit in the first half.

Kumba's Sishen mine has since begun to ramp up operations, but Amplats workers have not yet returned to Amplats' Rustenburg, Union and Amandelbult mining operations, which include some of Amplats' most labor intensive shafts, and those that have suffered deepest compression in margins since 2008.

(Reporting by Clara Ferreira-Marques; Editing by Jane Barrett)