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<br />.' <br /> <br />4') <br />~ u <br /> <br />. <br /> <br />~j r\.... - <br />~..) t. .~/ <br /> <br />sumnut with a top width of 30 feet. This would mean that <br /> <br />tho thickness of the dam up ''''o:ld down strc= "t thc river bed <br /> <br />would be 3630 foet, or ne~rly three-q~~rters of a mile. The <br /> <br />cliffs were to bo pierced \vith small tunnels paral13l to the <br /> <br />river at nurnurous points well above ,~d outside thc lines <br /> <br />of the dam in order lator to blow thc rock from these tunnels <br /> <br />I <br /> <br />into tho river for forming a loose rock dam. At a point <br /> <br />just ~hove where the upstream slopo of th~ dam would intersect <br /> <br />bed rock ~ turulel on each side of the river w~s to be filled <br /> <br />with powder and exploded, throwing the rock into the river <br /> <br />bed in such mc~er as to form a coffer dam ?nd divert the <br /> <br />. <br /> <br />rivcr into the diversion tunn~ls. This coffer d~m w~s to be <br /> <br />faced with smaller rock in ordor to serve its pu:~osc ?~d <br /> <br />th~n the river tu-~ed over tho coffor d?~, which it would <br /> <br />proceod to destroy by scouring the bed of tho river at tho <br /> <br />lowcr t03 and rolling the rocks o~ tae darn into thJ cavity <br /> <br />thus formed. <br /> <br />After such action h~ proceedod to a point of co~p~ra- <br /> <br />tive quiescence anoth~r blast from high~r tULL~els on both <br /> <br />sides of the river would blow additional qUL~tities into the <br /> <br />river just below the coffur dan and the rivur required to <br /> <br />work upon this mass for 'a short time. <br /> <br />With the high head <br /> <br />thus formed the scouring effect of the water upon the too of <br /> <br />the rock fill would be very pow"rful and ....ould carry away all <br /> <br />. <br /> <br />the finer material, but the large blocks of grm i tc th..~t \"iOuld <br /> <br />thus be provided could not be carried b:r the river but being <br />