Inventor: Deryck F. Boot, Knighton, England
Assignee: MinnesotaMiningand
Manufacturing Company, St. Paul, Minn.
A mining company would have tunnels, right?
Inventor: Deryck F. Boot, Knighton, England
Assignee: MinnesotaMiningand
Manufacturing Company, St. Paul, Minn.
A mining company would have tunnels, right?