JOHANNESBURG (Reuters) - South African gold output fell 12.3 percent in volume terms, while overall mineral production fell 6.3 percent in June compared to the same month in the previous year, official data showed on Thursday. Production of non-gold minerals declined by 5.4 percent, Statistics South Africa said on its website www.statssa.gov.za South African mine output has fallen after state-owned power utility Eskom suffered a near collapse in the electricity grid in January, which led to a five-day country-wide mine shutdown. Eskom has since supplied around 90 to 95 percent power to mines in the country, the world's biggest source of platinum and the second-ranked gold producer. | 
