DavidB4-bot
→top: clean up & uniformity
18:42
DanH
no edit summary
19:21
+14
Albertus
Link to subtractive mining
19:20
+5
Corrosive Mining
18:47
+178
Pachyderm
Also known as bord and pillar
14:27
+91
Aschlafly
New page: Room-and-pillar mining is the most common type of system for mining coal. In this system, the mine roof is supported mainly by coal pillars left at regular intervals. Rooms are places whe...
14:18
+868