A COMPARATIVE STUDY OF PPV ANALYSIS OF TUNNEL ROUNDS USING BOTH NON ELECTRIC AND PROGRAMMABLE ELECTRONIC DETONATION

摘要

Blast vibrations are of paramount importance in a society where ever increasing development is putting more stringent requirements on their control. Increasing civil development and more complex extraction scenarios make the trade off between proficient vibration control and productivity difficult to ascertain. Historically, reduction of induced vibrations levels was achieved through a reduction of MIC's leading to smaller but more frequent blasts in order to meet extraction targets.The utilisation of programmable electronic detonators as opposed to the more conventionally used non electric methods of initiation, have the potential to provide greater control of a blasts design through increased delay accuracy. The mechanics of a blast can therefore be more accurately estimated allowing for any vibration requirements to be considered and implemented in the design and thus remove some of the ambiguity.This paper presents a technique for the reduction of blast induced vibrations through the utilisation of programmable electronic detonators. By harnessing the increased precision of these detonators in comparison to non electric methods, delay intervals can be accurately chosen so as to reduce blast wave velocities. This hypothesis was investigated through the undertaking of three controlled blasts at the Camborne School of Mines test mine using electric and non-electric methods to provide a comparison. Blast data was analysed on a delay by delay basis so as to enable vibration levels at different stages of the blast to be established. New techniques utilising high definition surveying to quantify tunnel burden levels were applied at the face during the analytical process and fragmentation was also assessed