Technical Assesment of the Infuence of Use Bottom Air Decking ½ Meter on the Powder Factor Value in Lowwall Area C1 at PT Bukit Makmur Mandiri Utama Site Binungan, Kalimantan Timur

Abstract The research was conducted at PT Bukit Makmur Mandiri Utama Site Binungan, East Kalimantan. The research aims to reduce the powder factor value in blasting in the Lowwall C1 (include seam F5 Barat, F5 Expose, F5 Mine Out and F4) area which refers to the company’s target standard of 0.183 kg/m3, without changing the blasting results in the form of fragmentation value, digging time and material recovery. The powder factor is the ratio of powder filling to the volume of blasting results. Efforts to reduce the powder factor value can be made by using the ½ meter air deck experiment, this is done because the geometry cannot be changed and is optimal. Reducing the powder factor value using ½ meter air deck by paying attention to changes in the loading sheet value. After making the loading sheet value for ½ meter, there is a change in the amount of powder filling by 9-13 kg for each hole; the depth of the blast hole influences this reduction, After the trial was conducted, the powder factor value decreased by 3%, while the fragmentation value followed the target set by the company (below 50 cm), the digging time value produced was in accordance with the company (below 12 seconds), and the recovery value reached the target of 95%. So it can be concluded that the experiment using ½ meter air deck is successful and can be done for Lowwall C1 area.