History Highlight: The Rock Drill

Wood engraving of the Rock Drill invented by G. Sommeiller

One of the greatest … engineering feats of the age.” – from the newspaper the Michigan Argus, September 22, 1871

The Mount Cenis Tunnel was the first great Alpine tunnel and one of the first major uses of compressed air technology. The project was the brainchild of Italian engineer Germain Sommeiller who invented an improved rock drill. Construction started in 1857 and was expected to take 40 years. With 8 miles to drill, the project was going to be twice the length of any other previously constructed tunnel. Instead, with pneumatic tools, it took 14 years to complete and officially opened to traffic on September 17 of 1871.  

The tunnel connected France and Italy via Mount Cenis in the Alps, a notoriously difficult range to traverse. Having only been traversed by foot and with mules to haul goods until the triumph of the Railroad Era in Europe.

Did you know? They also used wet compressors to cool the air inside the tunnel for the miners as they made their way deeper through the rock.

Information via: A Complete History of Compressed Air and the Ann Arbor District Library