38 - 



As the beacons in alingments can nearly all be erected 

 in places which are out of reach of the highest water, their 

 construction, installation and maintenance will be fairly 

 economical. 



GENERAL PROGRAM OF THE PROJECTED 



WORKS 



Determination of 

 the unite princes 



Breaking up and 

 extraction of rock. 



By the aid of all the preceeding antecedents and the de- 

 tailed list of the work to be executed for the improvement 

 of the river to Concordia, the corresponding estimates 

 have been prepared. 



For the purpose of establishing the schedule of prices for 

 dredging, the plant which, the General Inspection actually 

 disposes of, as well as the cost of the work already carried 

 out by this Commission at the bars of Banco Grande, Altos 

 y Bajos and San Francisco, have served. 



With reference to the breaking up and extraction of the 

 bars of rock it is believed that the first operation can be 

 executed with explosives and also by heavy bars and rams, 

 which are allowed to drop from some height and for which 

 an installation can be made ; the second with Priestman's 

 crab excavators. 



The use of the falling ram is indicated to level the shallow 

 parts formed by sandstone of the «Chapicuy» bar, and 

 that of the explosives to break up the blocks or layers of 

 compact rock of the «Hervidero» and «Corralit02> rock. 



At the two last named bars and specially at the first one 

 the work of extracting the stone will be notabaly reduced 

 in consequence of depth existing near the places where 

 the explosives will be used. 



The Priestman's crab excavators can be erected on and 

 worked with perfect ease on board of steam hopper barges, 

 the holds of which ought to be lined before hand with tim- 

 ber in order to transport and discharge the extracted ma- 

 terial. 



In litis condition and by working in a rational manner, it 

 is believed that the excavation and extraction of 1 he stones 

 can be done at a maximum cost of 5 dollars national 



