Bulletin of the Geological Society of Malaysia, Volume 20, August 1986, pp. 871-881
Geological Survey Malaysia
Abstract: The Sungai Piah hydro-electric Project is situated some 57 km north-northeast of Ipoh. The area is mountainous and heavily forested.
The general outline of the project is for diverting water from Sungai Temor to Sungai Piah and then through a series of tunnels down to a lower elevation, thus developing an effective head of about 680 m and a generating capacity of 46.5 MW. Approximately 20 km of tunnel lines, comprising 2 stages of diversion and power tunnels, are proposed for the hydro-electric project.
Preliminary geological mapping was conducted in October and November 1982 and a feasibility study consisting of surface mapping together with geotechnical investigation and a diamond drilling programme was undertaken from early August to November 1983.
The area is underlain predominantly by coarse-grained porphyritic biotite granite with a 4 km x 7 km roof pendant to the northwest. The roof pendant consists of quartz-mica schist and calcsilicate hornfels.
The Stage I scheme is expected to encounter more faults than the Stage ll scheme which would require more lining for the tunnel. The Chier fault, which is the largest in the area, affected the location of both the tunnel portal sites of the Stage ll diversion tunnel. They had to be relocated further downstream away from the fault zone.