To speak generally,
It's probably a safe bet to say that ANY gold you find in nature will either
be Lode, Elluvial, or Alluvial. Though I'm sure somewhere somebody has
found a vein of gold laying open and exposed along a stream bed
how likely is that? Or, how likely in 2008 as opposed to the 19th century?
Therefore, without ever having been to these places mentioned it is a
pretty good bet that any gold found in or near any *moving* water will
be alluvial and therefore will obey the same physical laws that all other
alluvial gold does. So you would look for it as you would any other such
placer gold deposits . However the composition of local overburden and
bedrock may complicate things the same basic rules ought to apply.
However,... A quarry is by definition man-made. Any quarry you find
with water in it is almost certainly a *pool* of water and does not move.
Except perhaps to drain subterraneously or fill by rainfall or upwelling.
So the gold is not likely to be alluvial - unless it washed in there ! - so
the usual rules of placer deposition are not going to apply.
Gold in Virginia is commonly estimated by those geologists I have read
to be older gold - perhaps 400 MYA. I have personally quarried fossils
in VA. from the Devonian & Silurian Ages which are around that old. So
I suppose it's possible that your quarry is either exposing a deposit of
gold somewhere within its' walls that is leeching out or - if the quarry is
subject to flooding in major events - you have the Mother of All Bedrock
"Cracks" catching gold washed down from somewhere else.
It might be an interesting experiment to try panning in any local stream
that could conceivably flood into the quarry to see if it is gold-bearing.
If the quarry is in the middle of nowhere than you might try going over
the exposed sides of the quarry next. There could be an ancient alluvial
deposit exposed by quarrying that is leeching down into the quarry over
time. I wish you lots of luck and Big Gold.
Just My 2Cents Worth,