DIPPER DREDGES 167 



and the rock cut consist mostly of boulders and hardpan, underlaid 

 with limestone, shale and bed rock. The bed rock varies in depth from 

 6 in. to 14 ft., the layers being in some places 4 ft. thick. A 25-ft. 

 depth of water is required, and it has been found practicable to 

 secure the required depth with this dredge, using a 6-yd. dipper 

 which weighs (without teeth) over 11 tons; there are four teeth 

 on the dipper, weighing 800 Ibs. each. It would be difficult to state 

 the working capacity of the dredge in rock, as the latter is overlaid 

 with several feet of boulders and earth, all being dug at one operation, 

 but the capacity is estimated at from 40 to 50 cu.yds. per hour 

 in the rock alone. The capacity in soft material is about 400 to 

 500 cu.yds. per hour, using an 8-yd. dipper. The cost of running 

 this machine is estimated at $30 per hour. 



The dredge " Majestic " was built from plans of its owners, and 

 has proved very satisfactory in operation. The hull and boiler 

 were built by the Manitowoc Dry Dock Co. of Manitowoc, Wis. 

 The boom A frame, swinging circle, circle sheaves and dipper handle 

 were built by the Bucyrus Co. of South Milwaukee, Wis. The 

 three sets of engines, with drums and gearing, were built by the 

 Jackson & Church Co. of Saginaw, Mich., which company controls 

 the patents for the Edward cable-storage drum above described. 





