Harmony Gold workers in South Africa in underground protest JOHANNESBURG (Reuters) - About 1,700 workers at a Harmony Gold mine in South Africa refused on Friday to return to surface, protesting the sacking of colleagues who went on an illegal strike last week. The unrest at Harmony's Kusasalethu mine 65 km (40 miles) west of Johannesburg is the latest labor flare-up in South Africa's mining sector, which has been battered this year by a wave of often violent wildcat strikes. At least five workers were injured on Thursday at the mine when police fired rubber bullets to quell a riot triggered by the sacking of 600 miners. The protesting workers refused to return to surface after going underground for a shift on Thursday, said Harmony spokeswoman Henrika Basterfield. Water was being sent down to the workers and "lines of communication remained open," she said. The talks involved representatives from the Association of Mineworkers and Construction Union (AMCU). AMCU's turf war for members this year with the dominant National Union of Mineworkers has been at the root of much of the conflict this year which has seen over 50 people killed, damaging the country's reputation among foreign investors. South Africa's ruling ANC put its new No. 2, Cyril Ramaphosa, at the head of a charm offensive on Friday as it sought to reassure investors it would tackle economic inequality, which is also behind much of the labor unrest, without recourse to radical measures such as wholesale nationalization. The protesting miners at Harmony may have a tough time remaining underground, given the hot and uncomfortable conditions that prevail beneath the surface. Reporting by Ed Stoddard