Parts of the works of Middle Marsyangdi Hydroelectric Project

Middle Marsyangdi Hydro Electric Project is the Nepal’s second largest hydroelectric project. This is a run-off-river hydro project with installed capacity of 70 MW.

Himal Hydro played a major role in the construction of the project. It is the only domestic company with the necessary expertise and equipment to engage in a major project like this one.

The company was involved in the underground excavation as well as surface drilling works using drill rig where depth of drilling was up to 30m with diameter of hole up to 90mm in addition to open excavation, rock anchor and grouting at dam site of the project. The company undertook fully mechanized excavation using boomer and shotcrete robot and support work for the power tunnel, bypass tunnel, ventilation tunnel and surge shaft. The lengths of the tunnels range from 110 to 430 m and their areas vary from 15 to 44 m2. Pipe canopy tunneling was adopted for the excavation of 90 m long penstock tunnel of size 44 m2, which is the first of its kind in Nepal.

The surge shaft excavated by Himal Hydro is the largest underground shaft in Nepal. It is 22 m in diameter and 53.5 m high. Alimak Raise climber was used for excavation of the pilot shaft from the bottom to the top and the widening of the shaft was done from the top to the bottom dropping excavated material through the pilot shaft.


Borehole Drilling at Headworks

Project Middle Marsyangdi Hydroelectric Project
Works Borehole Drilling at Headworks
Borehole diameter 48 to 89 mm
Depth 5 to 30m
Period of Construction November 19, 2002 – October 9, 2003

Excavation and Support Work of the Ventilation Tunnel

Project Middle Marsyangdi Hydroelectric Project
Works Excavation and Support Work of the Ventilation Tunnel
Length 232 m
Size and Type of Tunnel Inverted D shaped, 3.5 x 3.7 m
Period of Construction April 8, 2006 – August 16, 2003

Surge Tank Excavation and Support

Project Middle Marsyangdi Hydroelectric Project
Works Surge Tank Excavation and Support
Length/Depth 53.5 m
Diameter 22 m
Period of Construction March 1, 2005 – February 2006

Penstock Tunnel Excavation and Support Work

Project Middle Marsyangdi Hydroelectric Project
Works Penstock Tunnel Excavation and Support Work
Size and Type of Tunnel Horse-shoe shaped, 90m long, cross section area 442
Period of Construction July 19, 2005 – April 2006

Excavation and Support of Power Tunnel and Surge Tank Bypass Tunnel

Project Middle Marsyangdi Hydroelectric Project
Works Excavation and Support of Power Tunnel and Surge Tank bypass Tunnel
Power Tunnel Horseshoe shape, dia 6.2 m, Length 296 m
Surge Tank Bypass Tunnel Inverted D shape, 5.4 m wide and 5.7 m high, Length 109 m
Period of Construction July 19, 2005 – April 2006