Proposta de ensaios visando melhorias na perfuração e carregamento dos furos na mina de salgema de realmonte pertencente a empresa italiana Italkali S.p.A.

Abstract

In the present study, developed in the Realmonte’s rocksalt mine, are suggested some improvements in the stages of drilling and charging of holes in order to increase the yield of blasting, advance per round and openings security level. The underground mining through the traditional method of drilling and blasting with explosives presents some points that deserve special attention including the steps of drilling and charging of holes . The control of positioning and straightness of holes approaching the most firing pattern in situ to that idealized, directly influences the blasting success, regarding both the fragmentation and displacement of rock and the yield per round. Holes so close can cause the load sympathy detonation, not respecting the delay time, increasing the maximum load for waiting as well the levels of vibration; likewise holes faraway results in blocks large, that are difficult to be transported, and require, in extreme cases, a secondary blasting, increasing costs and cycle times. Similarly the step of charging must be conducted so that the remaining rock do not be overmuch disturbed, through the generation of new faults and fractures, contributing to the increased instability of the openings. Simple measures such as the installation of an inclinometer in the drilling machine used in the mine and the redistribution of the explosives cartridges in a rational way in the holes may increase by approximately 20% the advance per round and by 30% the blasted volume after each detonation, and reduce, accordingly, the charge ratio up to 21 % .