Modelling of Relationship between Drilling Parameters of Underground Blasting with Rock Blastability in Phosphate Mines

Rock blastability classification is a prerequisite for determining labour quotas, designing blasting programmes and controlling the unit consumption of explosives. In order to realize a real-time grading of rock explodability, a measurement of in-situ drilling parameters of carbon-bearing muddy dolomite during the excavation process of $P{h}_1^3$ ore body and roadway in the Shukongping phosphorus mine has been carried out based on the KJ212-1 full-hydraulic boring drilling truck. Combined with the indoor uniaxial compressive strength test, the relationship model between the uniaxial compressive strength R_c and the drilling speed V, the drilling hole diameter D and the rotary pressure M was respectively established and verified. Finally, the model is substituted into the solidity coefficient f relationship equation to derive a model for the relationship between the blasthole drill-following parameters and the rock blastability classification. The results of the study show that the average rate of difference between the uniaxial compressive strength calculated by the relational model and the results of the indoor uniaxial compression tests is 5.5%, which demonstrates the reasonableness of applying the model to the real-time prediction of rock blastability. This model provides a more convenient and fast method for real-time grading prediction of rock blastability. The results show that the dolomitic banded phosphorite, mud banded phosphorite and dense banded phosphorite are medium explosive, carbon-bearing mud dolomite is difficult to explode.