Baga Nimba or D'mba

The Baga Nimba, otherwise known as D'mba, is one of the most important art forms. It symbolizes the mother of fertility, protector of pregnant woman, and presides over all agricultural ceremonies. Dancers often wear these masks by carrying them on their shoulders. These masks rise more than eight feet off the ground and often weigh more than 80 lbs.

Source: http://www.randafricanart.com/Baga_Nimba.html