Abstract: The rock breaking plant in a open pit mine is a complicatedly designed steel-concrete structure. Plan selection for demolition blasting of the structure with medium-to-small drill-holes, technical design of the demolition blasting operation, and measures for safety of field practice are all discussed in the paper. Result of the field operations show that the application of the medium-to-small drill-hole blasting technique is effective and reliable and can be referred by other field practices.