The Canadian head of Congo’s state mining firm Gecamines stepped down from the troubled group on Wednesday following four years at the helm.

Paul Fortin told Reuters he was originally appointed for 18 months but stayed on longer to help iron out issues created from neglect and maladministration.

Under his tenure, Gecamines went from being a non-functioning state miner to a landholder joint venture partner in a period when copper and cobalt mining were considered by many international firms for investment in the Congo.

Fortin said the company is far from trouble-free, however, saying “you chip away at the problems, but they are still there”.

Denying any replacement from outside, Congo deputy mines minister Victor Kasongo said that Calixte Mukasa, a former deputy of Fortin, will step in as acting chief executive.