Page:Popular Science Monthly Volume 79.djvu/432

428

Gas has been found in several of the tunnels; hence, in mining, safety devices will be necessary.

At more than 300 places within the field more or less development work has been done. But no extensive mining has been carried on. The most prevalent kind of work consists of small surface openings. However, more than 30 drifts or tunnels have been run with an aggregate length of more than 3,000 feet. The most systematic development work has been done on the Cunningham, the Controller Bay, the English