Rwanda has signed a five-year mining contract worth USD39 million with a unit of Oman's Mawarid Mining LLC to extract tin, tantalum and niobium, the mining ministry said on Tuesday. Mining, which the government says contributes about 1.5 percent of Rwanda's USD7.9 billion gross domestic product, is the East African country's second-biggest source of foreign exchange behind tourism, with metallic ore coltan bringing in the most earnings. The Ministry of Natural Resources said that it had signed the agreement with Tri Metals Mining -- Mawarid's Rwandan subsidiary -- to extract the minerals in the Bisesero concession in Western Province. Tantalum from coltan is used to make tantalum capacitors used in electronic products. (Reuters)