Tl'NNKLS TIIKorcll MAUD ROCK 118 



of January, IJ'OO). At Brigue, where there are three drilling- 

 nmi-hines in No. 1 and two in tin- parallel heading, the total 

 length i-xt -avaird was 995 yds. or 6,409 cu. yds. in 89 working 

 days, the average cross-sectional area being 57 sq. ft This re- 

 quired 507 attacks and 3,066 holes, which had a total depth of 

 26,600 ft., and 14,700 re-sharpenings of the drilling-tool, with 

 44,000 Ibs. of dynamite. 



The average time occupied in drilling was '2 hrs. 45 iniiis., 

 while charging, firing, and clearing away the cUbris took 6 hrs., 

 35 mins. At Brigue 648 men and 29 horses were employed at 

 one time in the tunnel. At Iselle the numbers were 496 men 

 and 16 horses, working in shifts of 8 hrs. Outside the tunnel, 

 in the shops, forges, etc., the men work 8 hrs. to 1 1 hrs. per 

 day, the total being 541 men at Brigue and 346 men at Iselle. 

 On the Italian side, where the rock is very much harder, there 

 were three drilling-machines in each heading ; the total length 

 excavated, with a cross-sectional area of 62 sq. ft, was 960 yds. 

 or 6,700 cu. yds. in 91 working days. This required 61,293 

 re-sharpened tools, 758 attacks, 7,940 holes with a total depth 

 of 33,000 ft,, and 56,000 Ibs. of dynamite. The average time 

 spent in drilling was 2 hrs. 55 mins., and in charging and clear 

 ing 2 hrs. 36 mins. Thus, in the hard gneiss, to excavate 1 cu. 

 yd. of rock required 8 Ibs. of dynamite, and each tool pierced 

 6 ins. of rock l>efore it required re-sharpening. 



Up to January 1, 1900, the total length of heading on the 

 north side was 2,515 yds., and on the south side 1,720 yds,, or 

 a total of 4,235 yds. out of 21,575 yds., the full length of the 

 tunnel. Allowing for unavoidable and unforeseen occurrences, 

 such as strikes, war, etc-., the contractors expect to complete 

 tunnel No. 1 and the parallel heading by May, 1904. 



