Undercharge /(?)/

Un·der·charge

Undercharge

v. t.
  1. To charge below or under; to charge less than is usual or suitable for; as, to undercharge goods or services.
  2. To put too small a charge into; as, to undercharge a gun.

Phrases & Compounds
Undercharged mine
a mine whose crater is not as wide at top as it is deep.

Undercharge

n.
  1. A charge that is less than is usual or suitable.