Geomechanical characterization and exploitation method design of the Polloc limestone deposit, Cajamarca – Peru

Abstract

The present Investigation analyzes the Geomechanical Behavior of the Polloc Limestone Deposit, located in the Encañada District, Cajamarca Province, whose extension is 10 hectares. The purpose is to define the Design of the Exploitation Method of the limestones belonging to the Pulluicana Group (Yumagual Formation) of the Upper Cretaceous. 6 Stations were analyzed to define the Geomechanical Behavior of the Reservoir, using RMR89, RQD, RCU and GSI parameters, determining that the Rock Quality according to the Deere's RQD is Medium for stations EG 3 and EG 5 and Good for stations EG 1, EG 2, EG 4 and EG 6. According to Bieniawski's RMR89 Classification, the Rock is of Regular Quality at station EG 5 and Good at stations EG 1, EG 2, EG 3, EG 4 and EG 6. According to the Geological Resistance Index GSI, the Rock is of Good Quality for Stations EG 1, EG 2, EG 3, EG 4, EG 5, EG 6. From the results obtained in the RocData Software, cohesion between 0.718 and 2.074 was calculated. MPa; and friction angle between 45.22° to 49.32°, determining a compact and hard rock. The DIPS software reported low percentages of flat breakage and wedges. With the results obtained, we designed the Exploitation Methods for Ascending Staggered Banks, whose design parameters are bank height 7m, bank width 6m, working angle 75° and final slope angle 42°.