Modelagem cinemática de estabilidade de rocha: estudo de caso para mina subterrânea da Fazenda Brasileiro Desenvolvimento Mineral, Barrocas-Bahia, Brasil

Abstract

The definition of the rocky mass kinematic behavior after the digging of a tunnel or the galleries of an underground mine is fundamental so as to prevent accidents involving rock sliding. Thus, it is proposed that we make the cinematic modelling of the main families of discontinuities and the predominant shistosity in the mine galleries to qualitatively measure potential zones for rock sliding on the form of wedge blocks. The current work aims to make the cinematic modelling of the main discontinuity families that might influence on rock sliding and falls which compromising miners’ safety. For so, we used the rocky massif cinematic modelling method in order to analyze possible kinds of ruptures that may occur due to the presence of discontinuities untoward the digging orientation. The measures of the discontinuities and the shistosity were brought through geological mapping and bore holes description, with the total of 1488 measures of discontinuity families and 758 shistosities. The cinematic modellings were made considering the weighted averages of the discontinuities J1 (078º/075º), J2 (290º/075º), J3 (117º/078º), J4 (240º/075º), J5 (059º/080º) and the shistosity Sn (177º/052º), the orientation N00º, N90º, N180º e N270º, the (90º) inclination towards the wall and (45º) to the gallery’s roof and friction angle of (34º) and (49º). This paper concludes that three parameters influenced on the probability of wedge blocks formation occurrence on potentially unstable zones. Digging orientation N00º and N270º, (90º) wall inclination and (34º) friction angle were the parameters that showed the highest possibility of wedge sliding events inside the galleries of the underground mine.

The definition of the rocky mass kinematic behavior after the digging of a tunnel or the galleries of an underground mine is fundamental so as to prevent accidents involving rock sliding. Thus, it is proposed that we make the cinematic modelling of the main families of discontinuities and the predominant shistosity in the mine galleries to qualitatively measure potential zones for rock sliding on the form of wedge blocks. The current work aims to make the cinematic modelling of the main discontinuity families that might influence on rock sliding and falls which compromising miners’ safety. For so, we used the rocky massif cinematic modelling method in order to analyze possible kinds of ruptures that may occur due to the presence of discontinuities untoward the digging orientation. The measures of the discontinuities and the shistosity were brought through geological mapping and bore holes description, with the total of 1488 measures of discontinuity families and 758 shistosities. The cinematic modellings were made considering the weighted averages of the discontinuities J1 (078º/075º), J2 (290º/075º), J3 (117º/078º), J4 (240º/075º), J5 (059º/080º) and the shistosity Sn (177º/052º), the orientation N00º, N90º, N180º e N270º, the (90º) inclination towards the wall and (45º) to the gallery’s roof and friction angle of (34º) and (49º). This paper concludes that three parameters influenced on the probability of wedge blocks formation occurrence on potentially unstable zones. Digging orientation N00º and N270º, (90º) wall inclination and (34º) friction angle were the parameters that showed the highest possibility of wedge sliding events inside the galleries of the underground mine.