At the foot of a slag heap some 40 metres high, Adi Kalie Bangura showed the black welts that dot his arms and legs that he says are the result of drinking and bathing in water contaminated by Sierra Leone’s largest diamond mine. The water “makes us get headaches and feel sick in our stomachs,” said Bangura, a traditional healer and community elder in Koidu, the largest city in the West African country’s diamond-rich Kono district. The aluminium roof of the mud brick house he shares with a dozen family members is pockmarked by holes he says are the result of rocks loosened by years of blasting by the mine.