availability of stone

Quoted text begins.What a cool trip Norman. How is this quarry operation getting the
stone out?
Is it all blasted?
End of quote.

Hey Daed,

Some time ago you asked me this question after my trip to the quarry,
and I intended to get back to you but never did. Sorry about that. I
wanted to get some more info from the quarry people but they seem to
work at a slower pace than the rush-rush world I often live in.

The quarry is not large, and they don't own the land but rent about
10 acres. They were working three benches. I saw one drilling crew, a
crew running a large saw, and one very large front end loader moving
blocks. They first cut both sides of the bench with a wire saw, then
they drill the bottom horizontally and the back vertically with the
holes fairly close together. When the block is loose they drill it
vertically again into smaller blocks, knock them down and drill them
yet again. Most blocks were very roughly 4x4x10, some bigger, some
smaller. All were cut nicely at right angles. Blocks are examined for
faults (seams, cracks) by an engineer and classed into three grades
and then moved to different piles with the loader. The blocks are
numbered and they have data sheets on the computer for every block in
stock.

Some things are still not clear to me (because I wasn't there long
enough to observe the whole process). For example, how do they set up
the wire saw to make the initial cuts into the bench? I doubt they
can just cut into the face. Do they thread the wire through drill
holes? If so, how do they get the holes to join up exactly and how do
they fetch the wire? Once fully drilled, the block is still attached
at many points by webs of rock between the drill holes. How do they
knock it loose, with a light charge or with the loader, or does it
break loose under its own weight? Why not drill the whole thing (why
use the saw)? I assume they drill into small blocks at the end,
rather than from the get-go, to maximize the block size with no flaws.

Those were my main questions. Maybe you or somebody else on the list
can answer them.

n