The Great Bore
A Souvenir Of The Hoosac Tunnel

The old bore at the east encl was made available by cutting it to the required size. In 1863 work was begun on the central shaft. In 1866, taking the hint from Mont Cenis tunnel, machine drills, driven by compressed air, were substituted for hand drills. The Deerfield river was dammed at an expense of nearly $128,000. It was thought that by this means sufficient power might be furnished to supply com- pressed air not only at the east encl, but, through pipes, at the central and west shaft workings. The dam was a disappointment. It did not even supply enough power for the east end. A year after the mouth of the central shaft was opened work was begun on the new west end heading, and with it one of the most disheartening pieces of work on the tunnel was commenced. The miners struck “de- moralized rock, ’ a rock which in its normal con- dition was like rock, but which when exposed to the influences of the air and water ran like quicksand. It was not until drifts had been run out for a con- siderable distance on either side of the line to drain oil the water and a complete casing of timber had been erected inside, that progressive work could be resumed. In 1866 George M. Mowbray introduced nitro-glycerine as an explosive, coincident with which the feasibility of firing the blasting charge by electricity was proven. When the state stopped