mortars and amalgamated with the gold in the ore. The stamps were periodically stopped and the amalgam was retrieved and then sold to banks or the mint.; The interior of a stamp mill, possibly the Iron City Stamp Mill in Blackhawk, Colorado, shows...
Ore-dressing plants--Colorado--Blackhawk--1870-1910.; Ore-dressing--Colorado--Blackhawk--1870-1910.; Blackhawk (Colo.)--1870-1910.; Gilpin County (Colo.)--1870-1910.; Gold mining--Colorado--Blackhawk--1870-1910.