After 15 years of construction work, the 9.5-meter (31-foot) widedrilling machine will bore through the remaining 1.5 meters of rock to join two ends of the tunnel some 2,000 meters under a mountain.
Gas drilling projects, such as Jonah Field, impede pronghorn migration, and new homes restrict corridors to no more than a few hundred yards wide in places.
乔纳气田这样的天然气钻探项目妨碍了叉角羚的迁徙，一些地方的新住房把叉角羚走廊缩小到不足几百米宽。
3
Exploiting shale also requires drilling lots of wells-something that might prove harder in densely populated Europe than in America's wide-open Spaces.