Implementation of Slope Drainage System for Optimal Slope Design at the Anfisa Open Pit, Khabarovsk Territory, Russian Federation
Zhdanov, Sergey; Kolpakov, Viktor
JSC Polymetal Engineering, Russian Federation
Open pits’ slope angles determine company profit and work safety. Steep slope and benches angles increase company’s profit but increase risks of landslides. Thus, slopes design should be optimal – profitable and safe. Groundwater negatively influence on slope stability. Implementation of slope depressurization greatly influence on slope stabilization and reducing negative risks.
The object of the study is Anfisa open pit in gold mineral deposit “Albazino”, situated in Khabarovsk Territory, Russian Federation. Complicated geology conditions along with low hydraulic permeability of rocks are the reasons of high groundwater level in the South and South-East slopes of Anfisa open pit which significantly influences open pits slope stability.
The main goal of the investigations is optimal drainage system development at South and South – East slopes of Anfisa open pit for slopes stabilization.
The following tasks solved in terms to assess effectiveness of development of drainage systems:
- Interpretation of geomechanical core documentation in terms of determination of hydraulic rocks characteristics. This innovatory approach base on the Q – classification system related to hydraulic properties. Geomechanical core documentation conducted in accordance with the standard of International Society of Rock Mechanics (ISRM). Documentation result contains rock characteristics according with Rock mass classification – Q-system.
- Development of 3d numerical model of groundwater flow in Visual Modflow flex 5.1.
- Slope stability assessment considering impact of different drainage systems. Three types of drainage considered: vertical pumping wells, horizontal wells and underground tunnel. Drainage scenarios modelled on groundwater flow model.
Finally, economically feasible and effective drainage by underground tunnel selected. The drainage system plan is going to be implemented during the year 2019. Comparison of factual and prognosis effectiveness will be estimated in the closer future.