South Africa’s largest gold refiner is operating below capacity as output from local mines dwindles and supplies from elsewhere on the continent are scooped up by unaccredited rivals.

The 102 year-old Rand Refinery in the east of Johannesburg – the only African refiner accredited with the London Bullion Market Association – is running at about 75% of capacity, said CEO Praveen Baijnath. While it still processes the output of its biggest shareholders – AngloGold Ashanti, Harmony Gold Mining and Sibanye-Stillwater – about half of the continent’s gold, from artisanal and small-scale miners, goes to smaller unaccredited refiners.

“Our capacity is not fully utilised,” Baijnath said in an interview. “So should there be an increase in deliveries, we would be able to step up.”

That surplus capacity partly stems from the demise of South Africa’s gold industry, where output peaked decades ago. The plant was originally built to end the practice of shipping crude bullion to London from the vast Witwatersrand basin, the source of half the gold produced on earth. Now power outages are crippling the nation’s economy and threatening to hasten the end of those operations, the CEO said.

Rand Refinery also sources gold from Ghana, the Democratic Republic of Congo and Tanzania – the continent’s top producers – but much larger flows are ending up with smaller smelters that have sprung up across Africa. The plant aims to stay competitive by investing in new technology and improving the logistics of hauling gold dore from across Africa, including sometimes using charter flights, Baijnath said.

There’s currently no market pressure to curtail the refinery’s operations further, said Baijnath.

So far, the LBMA’s minimum output requirements and stringent rules around responsible sourcing have precluded other African refineries from gaining accreditation. That hasn’t prevented them from finding markets for their bullion in Dubai and some European countries, Baijnath said.

Many of those unaccredited plants are in South Africa, where illegal mining has long been a problem. The proliferation of some of those refiners could in turn be spurring gold smuggling across the continent, he said.