Por: Johnnie Ramos Ayala, Geo-Logic Perú.

Trabajo ganador de ESG en el Foro TIS de PERUMIN 37.

Abstract

This hydrogeological study was carried out in the province of Angaraes, Huancavelica region. The study focused on mine closure, specifically on the mining component known as the bocamina (mine entrance). Mine water flowing through these mine entrances is often acidic and contains high concentrations of heavy metals. Therefore, it is crucial to mitigate mine effluents once operations have ended.

One of the most efficient alternatives is to seal the mine entrances with watertight plugs, with the goal of achieving zero effluent discharge. The purpose of this study is to determine groundwater recharge and the behavior of the water table after closure.

However, the use of watertight plugs presents several challenges: hydrostatic pressure could fracture or break the plug; infiltration may occur through fractures around the closure; and acidic water could percolate from adjacent zones near the mine entrance. These situations could generate environmental impacts on surface and groundwater bodies.

The results of the numerical model provided projections of the water table level after closure, assuming the mine entrances were sealed, and estimated the time required for mine workings to reach saturation. Furthermore, the model enabled the prediction and estimation of potential leakage zones and the emergence of new underground discharge points (springs), as well as other water bodies recharged by subsurface flow.