Monitoring rock movement and—controlling ore loss and dilution associated with blasting at Geita and North Mara Gold mines, Tanzania

Abstract

ABSTRACT We present findings from a blast movement monitoring research conducted as a part of mine to mill campaign at the Geita Gold Mine—and additional data from blast monitoring practices at North Mara Gold Mine. These include measurement of the blast-induced rock movement and perimeter translation after blast derived from a blast shot at Nyankanga pit (Geita Gold Mine) and three other shots at the Nyabirama pit (North Mara Gold Mine). Using Blast Movement Technology, 34 movement-monitoring balls installed in 13 blast-monitoring boreholes made possible estimation of the average vertical and horizontal ore movements in the studied blast shots. Recorded ore movement estimates average horizontal and vertical movements of 3.69 and 1.56 m, respectively, at the Nyabirama pit and average horizontal and vertical movements of 4.5 and 2.48 m, respectively, at the Nyankanga pit. Based on the estimated material movements, zones of ore losses and dilution are established and new dig lines are proposed from successful ore block translation in all blast shots.