Aetna furnace

Pine Baron

Feb 23, 2008
Sandy Run
While recently exploring the Ætna Furnace site in Atlantic County, I found a rather large (10"x8") piece of slag. You can see the the traces of iron along with the impurities (slag). What interests me is the amount of charcoal remaining. I've found hunks of slag with a random piece of charcoal, but never this much.

I was wondering if anyone has found a piece of slag with this much charcoal? And if you know the reason? (Insufficient heat, furnace going out of blast, etc.) I found this thread,, here on the forums. It was very helpful in determining hot/cold blast slag. According to the info posted, this piece is hot blast slag. Then why the excess amount of charcoal? Any suggestions would be appreciated.