Ora Banda Gold Mine is located in the Eastern Goldfields of Western
Australia. Mining is carried out underground by sublevel open sloping
resulting in large open stopes. A Mass Blast of approximately 250 000
tonnes was carried out in July 1994 to recover a rib pillar between two
stopes, and the crown pillar between the underground mine and the
abandoned open pit above. Strategic development within 50 m of the blast consisted of two
ventilation shafts and the main decline. This development required careful
design and prediction of the blast results. This paper describes the design of the blast, the prediction of the likely
effects, the measures taken to reduce the risk to important development,
and the results of the blast.