Although this unit will quickly grind your samples down to powder, it is meant to be a sampling machine. it is not intended to be a high production rock crusher. the cobra portable rock crusher weighs about 10 lbs. grinding chamber dimensions: 7.5 inches across x 3.5 inches wide x 9 inches tall including feed.Apr 04, small jaw crusher - 911metallurgist. the 911mpejac23 is a small jaw crusher of 2.25 x 3 manufactured to easily crush any rock from 2 (50mm) down to a d50 of 700 micron (28 mesh) which also correspond to a crushed discharge p80 size of 80% passing microns or 14.