How Complexity Analysis contributes to blasting practice

摘要

Blasting in geological bodies is an industrial process acting in an environment characterized by high uncertainties (natural joints, faults, voids, abrupt structural changes), which are transposed into the process parameters (e.g. energetic transfer to rock mass, hole deviations, misfires, vibrations, fly-rock...). The approach to this problem searching for the “optimum” result can be ineffective. The geological environment is marked out by too many uncertainties, to have an “optimum” suitable to different applications. Researching for “Robustness” in a blast design gives rise to much more efficiency. Robustness is the capability of the system to behave constantly under varying conditions, without leading to unexpected results. Since the geology varies from site to site, and often from bench to bench on each site, setting a robust method can grant better results in varying environments, lowering the costs and increasing benefits and safety. Complexity Analysis (C.A.) is an innovative approach to Systems. Under this point of view, the blast is a System consisting of drilling, charging and initiation parameters as an input, the geology as the working environment and the fragmentation as the output. C.A. allows to analyze the Complexity of the Blast System and the criticality of each variable. The lower is the complexity, the more robust is the System, and the lower is the possibility of unexpected results; critical complexity is the point beyond which the system starts to become unstable, being able to change behavior unexpectedly and cause surprises. By performing C.A. on field data and on the models used to design blasts, we can deduce: the complexity degree of each model; the complexity degree of a real blast; how much each variable influences the resu which variable is more critical. By knowing the complexity of the blast, the method which grants the highest performances can be chosen. By identifying the criticality of variables, the part of the work to be focused in order to solve the problems encountered is also known. The paper presents the results obtained thanks to the C.A. approach in an underground gypsum quarry (Northern Italy), exploited by conventional Rooms and Pillars method by drilling & blasting.