This paper describes the ventilation planning that was performed for the P.T. Freeport Indonesia’s Grasberg Block Cave (GBC) deposit located in the province of Irian Jaya, Indonesia. The mine is located at an elevation of around 3,000 m in the Puncak Jayawijaya Mountains and about 90 km from the coast. The GBC mine will be one of the largest underground block cave mines in the world with projected production at 160,000 tons per day. Primary personnel and supply access to the mine will be via a 6.0 km tunnel called the AB Adits. From the AB Adits, a shaft will convey personnel and supplies up to the main workings in the GBC. Primary ventilation is through 2.6 km tunnels with four as intake and three as exhaust. A fourth exhaust is in parallel with the conveyor system. A series of network simulations were conducted to evaluate ventilation raise locations, size and number of airways, and the duties of the primary exhaust fans. Analyses also investigated fixed facility ventilation systems and dust control strategies for three 60,000 tpd crusher stations. The paper describes the challenges with the design due to limitations in the intake and exhaust airway tunnels, distribution of airflow over a large area, and the requirement to have a ventilation management system to control regulators and other infrastructure.
Click here to download the full paper
