Shares in fast-growing producer surge after drill results at Cote d'Ivoire "free dig" mine provide extensions of oxide mineralization and fresh resources.
Prices for the precious rocks have fallen almost 12% in the past year, amid weakening diamond jewellery demand from China, the second largest consumer after the U.S.
According to research house Wood Mackenzie, the need for investment is becoming desperate in zinc and lead and will be a major issue in the copper sector in the next few years.