This view shows the chief elements of the dimension stone quarrying operation. Shown here are a drop ball, drill, tipping boom, explosives truck and other quarrying equipment.
Before December 2000, when water jet drills and horizontal wire saws were introduced, quarrying was done by the methods shown in this next few views.
The view to the left shows many common elements of a dimension stone quarry. Shown here are a drop ball, drill, tipping boom, explosives truck and other quarrying equipment.
Quarrying (below) takes a keen eye to determine the "grain of the rock." The earlier method based on years of experience at this rock body was to propagate a horizontal crack eastward. This is done by drilling a series of closely spaced horizontal holes.
A small amount of black powder is placed in the drilled holes and detonated. Workers are so in tune with the rock grain that they can monitor the progress of the horizontal crack by observing stacks of a few small rock chips vibrating as the crack passes -- some, it is said, can even hear the rock cracking. This horizontal crack forms the base of a rock 'lift.'
The next step is drilling vertical holes to define the sides and back of the block (below).
Closely spaced vertical drill holes define the edge of the block to be quarried .