Autonomous drilling and blasting operations in open-pit mining: automation of the process cycle, drilling accuracy and management of blast fragmentation of rocks

Drilling and blasting is a basic stage of open-pit mining that governs the particle-size distribution in the muck pile and, consequently, the costs of excavation, haulage and processing. Blasting accounts for 20–35% of the mining cost and up to 90% of the rock breaking by volume. Manual operations cause drilling inaccuracy, excessive consumption of explosives, an increased oversize yield, higher seismicity and risks to personnel. The paper systematizes directions of drilling and blasting robotization across the following five process stages: drilling, pattern and charge design, charging, initiation and fragmentation diagnostics. It also introduces a unified five-level automation-maturity scale, i.e. manual → mechanized → automated → robotic → autonomous operations. An integral robotization efficiency index is proposed, with process weights normalized by their contribution to the effects. Fragmentation forecast is made using the Kuznetsov–Rammler model and the Swebrec function. The median fragment size shifts from 420 to 350 mm and the oversize yield drops from 7.8 to 2.9% for a model block (250 mm hole diameter). Industry effects of automation are generalized including a 50–75% reduction in the hole deviation, a 40–65% drop in oversize, a 5–12% decrease in the specific explosive consumption, a 10–20% gain in the drilling productivity and a 15–30% reduction in seismicity. In the typical and target scenarios the integral index equals 56% and 88%. Implementation barriers and a roadmap for drilling and blasting robotization within the process-control system and the digital twin of the pit are outlined.