Selection of mixed-flow fans for PT Freeport's DOZ Mine, West Papua, Indonesia

摘要

As part of the analyses to advance the DOZ block cave mine from 35,000 to 50,000 tonnes per day, the need for additional airflow and ventilation infrastructure was identified. The primary ventilation for the DOZ Mine is currently provided by five centrifugal fans located on the surface in the Dom valley (4,000m above sea level). The DOZ Mine is approximately 3,100m above sea level; hence the exhaust air is drawn 900 m up through ventilation shafts to the fans. In order to increase ventilation to the DOZ Mine, the solution selected was exhaust portals at approximately mine elevation in the valley wall above the mill site. Faced with limited-space at the portals, and noise considerations, a surface fan installation was discounted and underground fans were selected. The fans chosen for the DOZ ventilation project will be required to move a total airflow of approximately 780 cubic meters per second and develop a pressure exceeding 2.5 kilo-Pascals (3.4 kilo-Pascals sea level equivalent); additionally, the projected life of the fans will exceed 25 years. Careful consideration of the available fan designs and potential parallel fan installations led to the selection of twin parallel impulse-bladed (mixed-flow) fans rather than the more typical (for mining) reaction-bladed (vane-axial) fans. This paper describes the selection process and design for the application of an established fan technology in a novel underground mining application. The new DOZ exhaust fans are scheduled to be in service in April 2006.