Isaacs, a former American mining executive, will fill the position of president and chief operating officer at BHP Billiton's Ekati Diamond Mine in Canada, the Illawarra Mercury reported.
Isaacs joined BHP in 1997 after 20 years' experience in underground mining operations, mostly in West Virginia and Illinois in the U.S.
Bloomfield, who is currently the vice-president of health, safety and environment, has worked for BHP for 18 years.
He worked at Cordeaux and Tower collieries from 1990 and 1997 and was later responsible for integrating BHP and Billiton after the merger in 2001.
