Cass Plumber Messages 5,947 Reaction score 9 Points 0 Location Ohio Jul 1, 2007 #1 How is this for drilling a hole 4,600+ feet deep. http://www.livescience.com/technology/050407_earth_drill.html
How is this for drilling a hole 4,600+ feet deep. http://www.livescience.com/technology/050407_earth_drill.html