Perhitungan Produktivitas dan Biaya Pengeboran Overburden Menggunakan Drill Furukawa HCR 1500-D20II Mata Bor 5,5 Inch dengan HCR 1200-ED Mata Bor 3,5 Inch di area PT. Nusa Alam lestari.

Administratively, the mining concession area of PT NAL included inPrambahan, Talawi district, the city of West Sumatra province Sawahlunto, thedistance between the mine with a desert city (provincial capital boast) ± 90 kmeast of the city of Padang.PT. NAL do with the system open pit mining, where the method ofblasting is used for stripping rocks that have violence on the ability of excavator.Drilling tools PT. NAL using a drill Fukukawa HCR 1500-D2011 with5.5-inch bit diameter and 4 meters long rod, Fukukawa HCR 1200-ED with a 3.5inch diameter bit rod 4 meters.Productivity tools drill Fukukawa HCR 1200-ED is low and this isbecause not effective, the plan pengemboran incompatible with the field results.Overburden stripping so that the production does not reach the production targetof 30,000 tons that had been planned.After a comparison of the two drill bits drill bit that is 3.5 inch and 5.5inch drill bit, that pengemboran with HCR with HCR 1500-D20 1200-ED in termsof cost per meter, per-minute production is better than drilling by using HCR 1200-ED this is caused by the volume of drilling such as burden, spacing, and depthbut long compared to HCR 1200-ED working less time consuming compared toHCR 1500-D20II.The result is more effective than the 5.5 inch 3.5 inch. Production drillingm3/hr 317.16 5.5 inch 3.5 inch drilling and production can only 79.15 m3/hr.