The proneness assessment of a mineral deposit to tectonic rockburst: A case-study of Yuzhnoe deposit

Abstract

The procedure of the proneness assessment to tectonic rockburst (with fault-slip mechanism) is insufficiently described in guidelines and regulatory documents, thus, additional investigations are required in this regard. The tectonic rockburst proneness criteria at Yuzhnoe deposit, Primorye are considered to be the location of large faults in the modern stress field and the critical stress state of rock mass. It is found that the maximum (compression) principal stress, reconstructed using the methods of tectonophysics and the data on rock mass faulting, fits the orientation of the maximum compression in the stress field, determined by instrumental measurements. In this stress field, in the plane nearby the plane of the effective maximum shear stresses, a large fault exists and is traced underground and on ground surface for more than 10 km. The analysis of geodynamics at the deposit, deformation of boundaries of underground excavations, core discing in wells far from the underground excavations, as well as rock bursts both at the study deposit and at the similar Nikolaevskoe deposit nearby shows that the level of the natural stresses at Yuzhnoe deposit is rather high and the rock mass is everywhere in the critical stress state. Yuzhnoe deposit is assumed to be to tectonic rockburst prone as both criteria are fulfilled: the rock massif is in the critical stress state and there is large fault which lies comfortably for mutual movement of rock blocks.The studies were carried out using facilities of the Center for Shared Use of Scientific Equipment at the Center for Processing and Storage of Scientific Data of the Far East Branch of the Russian Academy of Sciences, supported by the Ministry of Science and Higher Education of the Russian Federation, Project No. 075-15-2021-663.