Blasthole drilling technology

Drilling in Appalachian coal overburdens presents challenges to conventional tricone bit operations due to the high rates of advance. In 2005, design engineers Atlas Copco BHMT (formerly Baker Hughes Mining Tools) began creating and testing a new lug design for bits used in these coalfields. The design was aided by use of computational flow dynamics. The article describes the design development and testing. Average footage drilled per bit by the new streamlined lug increased an average of 32.3% at Coal Mine No. 1 and 34.5% at Coal Mine No. 2 over the standard lug previously used. Average bit life increased by 32.3% at Coal Mine No.1 and 34.5% at Coal Mine No. 2. 3 figs., 2 photos.