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 | 19 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 |