Experience in removing blasted underwater rock: Fid-Bau Portal

Experience in removing blasted underwater rock

Tavrizov, V. M.

Conclusion o| li]1.|Of all the methods of removing blasted rocks from under water (elevator, dipper, and grab dredges, land and floating devices, hydraulic excavators, cranes with diving stations, and directed blasts), elevator dredges, as a rule (if reference is not to the removal of the smallest volumes), are the most universal and suitable, since they provide the greatest productivity and low cost of the works. li]2.|The cost of explosives for crushing 1 m3 of rock by blasthole charges in the total cost of drilling and blasting operations is relatively small, especially if the volume of drilling operations for placing the explosives does not increase. Therefore, it is expedient to blast underwater rock with an increased powder factor providing guaranteed crushing of the underwater rock — mainly to the size of rubble. With the large powder factor necessary for good crushing of the rock, the cost of drilling and blasting operations increases somewhat (by about 7–10%, i.e., by 0.8–1.5 rubles/m3). However, the cost of removing blasted rock by the dredge decreases considerably more (by several rubles), as a result of which the total cost of rock-removing works decreases. li]3.|To reduce the cost of expensive rock-removing works, the blasted rock should be used more widely in constructing structures (regulating, port, etc.), bank protection, etc.