Eritrea expects to have four mines in operation by 2018 producing gold, copper, zinc and potash as one of Africa’s poorest nations looks to build an industry that can kick-start its economy, a top mining official told Reuters. Eritrea’s artisanal miners have long scratched for gold nuggets on deposits that stretch along the Red Sea, a geological formation known as the Arabian Nubian Shield, but the country currently has just one working commercial mine.