Drill and Blast in Gypsum Quarries: Optimization of Technical, Economic, and Safety Aspects in “Monte Tondo” Mid-mountain Case Study

Drilling and blasting operations are one of the common deals in open pit mining. Recently, mathematical rigorous patterns are on attention and digitalization and optimization of mining operations are highly suggested. In this work, drilling and blasting operations are modeled and various scenarios are simulated. The usual result of numerical simulations is the fragmentation curve caused by blasting. It is defined as a function of the blasting geometric pattern, the explosives’ type and quantity, and the rock-mechanics characteristics. The aim of this work is to improve the blasting efficiency in quarrying, through proper understanding of the fracture mechanisms and optimization of blasting alternatives. The analysis was developed over the Monte Tondo gypsum quarry, owned by Saint-Gobain (joint-stock company in Italy). The case study was modeled by O-Pitsurface®. After model calibration using the in situ quarry data, several optimization hypotheses were developed, starting from the original blasting scheme. Two fragmentation thresholds were applied. First, the minimum dimension of fragmentation to avoid additional breaking, and secondly, the limit of fragmentation dimension for the crushing feed. For each hypothesis, the appropriate parameters were defined. The optimized best hypothesis was finally selected, based on time saving of 145 h/year of work related to drilling and breaking; economic saving of €24,150/year, due to the blastholes numbers’ reduction; and finally, improvement of safety conditions by 12%, thanks to lower dimension of fragments which leads to an easier and safer management.