Figure 7. — Hoosac Tunnel. Group of miners 

 descending the west shaft with a Burleigh drill. 

 {Photo courtesy oj StaU Library, Commonwealth of 

 Massachusetts.) 



the heading was kept between 400 and 600 feet in 

 advance of the bench so that heading blasts would 

 not interfere with the bench work. The bench 

 carriage simply facilitated handling of the blasted 

 rock. It was rolled back during blasts. 



The experiments conducted by Haupt with machine 

 drills produced no immediate useful results. A drill 

 designed by Haupt and his associate, Stuart Gwynn, 

 in 1858 bored hard granite at the rate of % inch per 

 minute, but was not substantial enough to bear up 

 in service. Haupt left the work in 1H61, victim of 

 intense political pressures and totally unjust accusa- 

 tions of corruption and mismanagement. The work 

 was suspended until taken over by a state commission 

 in 1862. Despite frightful ineptitude and very real 

 corruption, this period was exceedingly important 

 inthe long history both oi Hoosac Tunnel and of rock 

 tunneling in general. 



The merely routine criticism of the project had by 

 this time become violent due to the inordinate length 



of time already elapsed and the immense cost, com- 

 pared to the small portion of work completed. This 

 sei sect to generate in the commission a strong sense 

 of urgency to hurry the project along. Charles S. 

 Storrow, a competent engineer, was sent to Europe 

 to report on the progress of tunneling there, and in 

 particular on mechanization at the Mont Cenis Tun- 

 nel then under construction between France and Italy. 

 Germain Sommeiller, its chief engineer, had, after 

 experimentation similar to Haupt's, invented a 

 reasonably efficient drilling machine which had gone 

 into service at Mont Cenis in March 1861. It was 

 a distinct improvement over hand drilling, almost 

 doubling the drilling rate, but was complex and highly 

 unreliable. Two hundred drills were required to keep 

 16 drills at work. But the vital point in this was the 

 fact that Sommeiller drove his drills not with steam, 

 but air, compressed at the tunnel portals and piped 

 to the work face. It was this single factor, one of 

 application rather than invention, that made the 

 mechanical drill feasible for tunneling. 



All previous effort in the field of machine drilling, on 

 both sides of the Atlantic, had been directed toward 

 steam as the motive power. In deep tunnels, with 

 ventilation already an inherent problem, the exhaust 

 of a steam drill into the atmosphere was inadmissible. 

 Further, steam could not be piped over great distances 

 due to serious losses of energy from radiation of heat, 

 and condensation. Steam generation within the 

 tunnel itself was obviously out of the question. It 

 was the combination of a practical drill, and the 

 parallel invention by Sommeiller of a practical air 

 compressor that resulted in the first workable applica- 

 tion of machine rock drilling to tunneling. 



The Sommeiller drills greatly impressed Storrow, 

 and his report of November 1862 strongly favored 

 their adoption at Hoosac. It is curious however, that 

 not a single one was brought to the U.S., even on 

 trial. Storrow does speak of Sommeiller's intent to 

 keep the details of the machine to himself until it had 

 been further improved, with a view to its eventual 

 exploitation. The fact is, that although workable, the 

 Sommeiller drill proved to be a dead end in rock-drill 

 development because of its many basic deficiencies. 

 It did exert the indirect influence of inspiration which, 

 coupled with a pressing need for haste, led to renewed 

 trials of drilling machinery at Hoosac. Thomas 

 Doane, chief engineer under the state commission, 

 carried this program forth with intensity, seeking and 

 encouraging inventors, and himself working on the 



210 



BULLETIN 240: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



