|
 |
 [Vietnam] Safer passage  North-South highway traffic over the Hai Van Pass 1,500 metres above sea level in central Vietnam will soon become safer, thanks to a pair of parallel 13m x 8.7 m and 5m x 4.5 m tunnels. Each will be 6,500 m long. The tunnels, scheduled for completion in September 2004, will bypass a century-old road that is renowned for both its scenic beauty and its danger - a number of vehicles plunge over the edge into the sea every year. The north end of the tunnel is being excavated by Japanese contractor Hazama Corp., which is using a three-boom Atlas Copco Rocket Boomer 195 rig, while at the south end, Vietnam's largest and most experienced tunnelling contractor, Song Da Company No. 10, is using a fleet of four Boomer 352 rigs. "Working two at a time, the Boomer 352 rigs at the main face drill 4.5 metres in five hours," explains Site Manager and Song Da 10 Vice-Director Nguyen Van Bay. "They have been drilling 250 holes, 45 mm in diameter and 76 102 mm holes for the V cut. The drilling time has now been cut to four hours since the arrival of our Rocket Boomer 195." The rock has an average compressive strength of 1,500-2,000 bar and the rock quality is quite poor. Atlas Copco Swellex bolts, among others, are used for reinforcement, and Atlas Copco service personnel service the rigs in both tunnels. |
|
|
 |
|
|
|
