Gem mining area. The third place in the world with gemmy cuprian elbaite, "Paraiba tourmaline".
The Paraíba-type tourmaline deposit is located near the eastern border of the Alto Ligonha pegmatite district, adjacent to the village of Mavuco in northeastern Mozambique. An approximately 3 km2 area has been mined for the tourmaline, which is hosted exclusively by secondary deposits (paleoplacers) buried beneath as much as 5 meters of soil.
Ref.:
http://www.gia.edu/gemsandgemology/620/30119/this_weeks_news_details.cfm1 entry listed.
