![0022:0129: U. S. Bureau of Mines Collection - C-797-BC Small Zinc-Lead Pilot Plant, South End ["In the center are two laboratory-size Herreshoff roasting or calcining furnaces, used in conditioning various ores for pilot-plant feed. On the right is an oven for drying the various plant products. In the right foreground is a small leach tank with agitator for extracting zinc and lead from oxidized ores with caustic solutions."]](https://d8e7jbdw4fu0e.cloudfront.net/4452/08edc7c0-c2c9-11ee-80d0-913e4ef26a17-wzIJH58.lg-nt@2x.jpg)
U. S. Bureau of Mines Collection - C-797-BC Small Zinc-Lead Pilot Plant, South End ["In the center are two laboratory-size Herreshoff roasting or calcining furnaces, used in conditioning various ores for pilot-plant feed. On the right is an oven for drying the various plant products. In the right foreground is a small leach tank with agitator for extracting zinc and lead from oxidized ores with caustic solutions."]