Underground Mine Development

Terms 

Deposit and Spatial Terms 

Back - roof , top , or overlying surface of an underground excavation
Bottom - floor or underlying surface of an underground excavation
Capping - waste material overlying the mineral deposit 
Country rock - waste material adjacent to a mineral deposit
Crown pillar - portion of the deposit overlying an excavation and left in place as a pillar 
Dip - angle of inclination of a deposit , measure from the horizontal,  also pitch or attitude 
Floor - Bottom or Underlying surface of an underground excavation
Footwall -   wall rock under the deposit
Gob - Broken , caved , and mined out portion of the deposit
Hanging wall - wall rock above the deposit
Pillar - unmined portion of the deposit , providing support to the roof or hanging wall 
Rib - Side wall of an excavation , also rib pillar
Roof - back , top , or overlying surface of an excavation 
Sill pillar - portion of the deposit underlying an excavation and left in place as pillar 
Strike - Horizontal bearing of a tabular deposit as its surface intersection
Wall rock - Country rock boundary adjacent to the deposite