overburden
1. over.bur.den \-'b*rd-*n\ vt : to place an excessive burden on 2. overburden \'o--v*r-.\ n : material overlying a deposit of useful geological materials
1. over.bur.den \-'b*rd-*n\ vt : to place an excessive burden on 2. overburden \'o--v*r-.\ n : material overlying a deposit of useful geological materials