Effect of detonator position on rock fragmentation: Full-scale field tests at Kevitsa open pit mine

The effect of detonator position on rock fragmentation was studied at the Kevitsa open pit mine. Five full-scale field tests were conducted where blasts divided into test and reference areas, compared with each other. In detonators placed or near middle point explosive column, in corresponding to conventional used mine, about 1–2 m above bottom blast holes. fragment sizes from both areas measured using shovel-mounted machine vision cameras image analysis. Both theoretical studies indicated that plays an important role fragmentation, column yielded significant improvement fragmentation. For example, percentages x20, x50, x80 are reduced by 10–27%, 11–30%, 8–31%, respectively; percentage large size fragments (>1.0 m) is 29–99%; small (<2.5 cm) increased 6–49%. • Detonator location for bench blasting. best charge length. significantly improved Fragment x50 11–24% tests.