From the information given, this is speculation on my part, but I would be 
looking upslope from the structure for footings that would have allowed a 
building to be put there, allowing level construction or perhaps a platform 
that extended out over the mine shaft for pulling up men and materials. Is 
there any evidence of wood in the bottom of the structure? To me that looks 
like a support structure that was used for building or framework associated 
with the shaft. With the walls as thick as they are, it was probably for 
something more substantial than just containment.
I am probably way off base, but that is what I would start trying to verify 
is that was a site I was working.

Cordially:

Richard W. Galloway
Archaeological Technician-USFWS
Anthropology Grad Student-University of Alaska, Anchorage
"Honor the past, Live in the present, Create the future." Anonymous

----- Original Message ----- 
From: "Jim Bates" <[log in to unmask]>


>I am trying to identify a stone structures next to two mine shafts on a 
>historic
> mine site on the Sumter National Forest in Oconee County , SC.  The site 
> was
> probably used in the 1850s and contains a couple of deep vertical shafts 
> (15 x
> 15, and 10 x 10) and several adits, trenches and smaller prospecting 
> holes.
> They were probably mining argentiferous galena (silver-lead).  The stone
> sturctures are about 15 feet from the shafts, are mud mortared fieldstone, 
> and
> about six feet square.  They are each located upslope of the shafts on 
> steep
> slopes and do not appear to have associated building foundations.  They 
> look
> like chimneys, but I have not seen soot or any charcoal or slag near the
> chimneys.  Photos are on the attached: