Commencing with the GBT Mine in 1978, P.T. Freeport Indonesia has consistently ramped-up underground mining operations at their Ertsberg District in Indonesia. Approximately 300 km of lateral development has been completed with future plans for an additional 900 km of drifting through the life of the mines. During 2012 schedules for the operations in this district require +60 km of lateral, and several kilometers of vertical development including multiple 6 m diameter raise-bored ventilation shafts and an 8.5 m internal winze. Such rapid development places a premium on the construction, maintenance and application of accurate ventilation models. Dating back to 1996 comprehensive ventilation surveys have been conducted, during which coupled airflow and pressure measurements are taken annually to update certain sections of the operations. These measurements have been executed using consistent standards and protocols allowing accurate comparisons to be made. This paper examines airway resistance data collected from the ventilation surveys considering specific factors such as over-break (design versus actual dimensions), method of excavation, airway type (ramp, conveyor, lateral drifting, Alimak, raise-bore), support type and dynamic losses. The measured data are benchmarked against published Atkinson friction factors.
