1 Answer
Mining
The most widely used exploration technique is the drilling of probe holes. In this practice a drill with a diamond-tipped bit cuts a narrow kerf of rock, extracting intact a cylindrical core of rock in the centre. These core holes may be hundreds or even thousands of metres in length; the most common diameter is about 50 mm (2 inches).
The hole left after extracting the material would be the probe hole.
http://www.britannica.com/EBchecked/topic/477567/probe-hole
10 years ago. Rating: 1 | |
Top contributors in Astronomy & Space category
Unanswered Questions
92lottery
Answers: 0
Views: 9
Rating: 0
kubetexchange
Answers: 0
Views: 4
Rating: 0
BONG88 - Bong88.co.com
Answers: 0
Views: 6
Rating: 0
Megahoki AgenJudi
Answers: 0
Views: 5
Rating: 0
W88 - Thế Giới Cá Cược và Giải Trí Online Chất Lượng
Answers: 0
Views: 8
Rating: 0
cakhiatvabccom
Answers: 0
Views: 7
Rating: 0
giabaomoto
Answers: 0
Views: 6
Rating: 0
fb68livecom
> More questions...
Answers: 0
Views: 8
Rating: 0