MECHANK Al. INSTALLATIONS FOR TUNNEL WORK 127 



At shaft 10 steam was provided by two Ingersoll boilers of 

 80 II. P. each, and by a small upright boiler of 8 H. P. There 

 were two 18 x 30 in. Ingersoll air compressors pumping into 

 two 4:2 in. x 10 ft and two 42 in. x 12 ft. Ingersoll receivers. 

 In tin- rxravation there were twelve 3^ in. and six 3jj in. 

 Ingersoll drills, four drills mounted on two double-arm columns 

 being used on each heading, and the remainder mounted on 

 tripods being used on the bench. Two Dickson cages operated 

 by one 12 x 12 in. Dickson reversible double hoisting engine 

 provided transportation for material and supplies up and down 

 the shaft. A Thomson-Houston ten-light dynamo operated by 

 a Lidgerwood engine provided light. Drainage was effected by 

 means of two No. 9 and one No. 6 Cameron pumps. At this 

 particular shaft the air exhausted from the drills gave ample 

 ventilation, especially when after each blast the smoke waa 

 cleared away by a jet of compressed air. In other workings, 

 however, where this means of ventilation was not sufficient, 

 Baker blowers were generally employed. 



Strickler Tunnel. The Strickler tunnel for the water 

 supply of Colorado Springs, Col., is 6,441 ft long with a Mo- 

 tion of 4 ft. x 7 ft. It penetrates the ridge connecting Pike's 

 Peak and the Big Honi Mountains, at an elevation of 11,540 

 ft. above sea level. The material penetrated is a coarse 

 porphyritic granite and morainal de'bris, the portion through 

 the latter material being lined. The mechanical installation 

 consisted of a water power electric plant operating air com- 

 pressors. The water from Buxton Creek having a fall of 

 2,400 ft was utilized to operate a 36 in. 220 H. P. Pelton 

 \vatn-\\lieel. which unrated a loO K. W. three-phase generator. 

 From this generator a 3,500 volt current was transmitted to 

 the east portal of the tunnel, where a step-down transformer 

 reduced it to a 220 volt current to the motor. The transmis- 

 sion line consisted of three No. 5 wires carried on cross-Ann 

 poles and provided with lightning arresters at intervals. Hie 

 plant at the east portal of the tunnel consisted of a 75 H. P. 



