URUMQI - Chinese geologists have discovered nitrate ore deposits in more than 10 places in Northwest China's Xinjiang Uygur Autonomous Region after three years' prospecting. Preliminary estimates show that the reserves total about 2.31 million tons worth about 7 billion yuan ($US845 million). Nitrate deposits are very rare. Only seven countries have reported discoveries. China ranks second in the world and most of its such reserves are scattered in Xinjiang.