Scott,

The feature you described does sound like iron ore reduction as in a
bloomery but as you are in an area rich in other ores, you may be looking at
a prospecting trial of some other mineral to assess the quality.  If you
have access to an XRF machine or have samples you could submit to a lab you
should be able to figure out what the original product may have been.   I
recently had a similar pit used to reduce bog iron from an 18th century site
in southern Delaware in which we had Carl Blair from Michigan Tech look at
the slag.

Bill Liebeknecht, RPA
Hunter Research, Inc.
Trenton, NJ 

-----Original Message-----
From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of
Williams, Scott
Sent: Monday, December 23, 2013 7:51 PM
To: [log in to unmask]
Subject: Slag question

A pit feature was recently found here in WA state that looks like a typical
earth oven of the area (i.e., big unlined pit with charcoal and oxidized
soil), but instead of fire-cracked rocks it has some kind of "frothy"
looking slag- the material is black, hard and looks silica-rich/glassy, but
soft enough to crumble or break with some pressure. It doesn't look like
slag from iron working to me, but my experience with iron slag is pretty
limited. I'm looking for suggestions of other processes that might have
created the material, or any thoughts on what could produce black,
finely-vesicular slag.  There's no glass or other historic debris in the pit
feature, and it looks like whatever created the slag was done in the pit-in
other words, it doesn't appear to be a refuse pit filled with clean-out from
another source.

If this sounds like anything you've encountered before, I 'd love to hear
from you!

Scott S. Williams
Cultural Resources Program Manager, WSDOT Environmental Services Office,
Mottman PO Box 47332, Olympia, WA 98504-7332
Ph: 360.570.6651
Mobile: 360.485.5350
Fax: 360.570.6633
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WSDOT Cultural Resources
Program<http://www.wsdot.wa.gov/Environment/CulRes/default.htm> on the Web

"Development is not stifled by history, but enriched by it."