UK-based mining giant Anglo American is planning to sell its oldest platinum mines in South Africa, in a decision that would lose 20,000 jobs.

The company’s South African operations account for around 40% of platinum production in the world and employ more than 40,000 people.

The sale would include mines that have been operating since 1950s and affect one-fifth of its global workforce, reported The Sunday Times.

"The sale would include mines which are operating since 1950s and affect one-fifth of its global workforce."

According to media reports, the assets are likely to be sold to a smaller local company.

The move is part of Anglo’s CEO Mark Cutifani’s plans to streamline the business by disposing of under-performing assets.

Anglo American aims to raise the profits from 8% in June to 15% by 2016 by divesting under-performing assets.

The company was recently hit by one of the longest and most expensive mining strikes in the country, which lasted for five months from January to June. It resulted in a loss of ZAR$11.27bn ($1.06bn) for Anglo.

During the second quarter ending 30 June, the company’s platinum production fell by 40% to 358,000oz due to a strike at Rustenburg, Amandelbult and Union mines in South Africa.

Disposal of the platinum assets is expected to help the mining company raise $4bn.

Anglo American spokesman James Wyatt-Tilby had previously said: "We have been clear that a number of assets in the portfolio are unlikely to satisfy our stated return criteria and will be divested at the right time."