CLIMATIC VARIABILITY AND ITS IMPACT ON HYDRAULIC LOAD AND OPERATIONAL RISK IN ACID MINE DRAINAGE TREATMENT IN AN OPEN-PIT COPPER MINE
DOI:
https://doi.org/10.59957/jctm.v61.i4.2026.11Keywords:
open-pit copper mines, water treatment, statistical modeling, risk assessmentAbstract
This study presents a long-term assessment of acid mine wastewater treatment at an open-pit copper mine in the Republic of Bulgaria, with the aim of evaluating treatment efficiency, the influence of climatic factors on hydraulic loading, and associated operational risks. A comprehensive dataset covering the period 2015 - 2025 was analysed, including pH, concentrations of Cu, Mn and SO42-, mine water flow, and key meteorological parameters. The results demonstrate stable neutralization and consistently high removal efficiency of copper and manganese (> 93 %), with effluent concentrations remaining below regulatory limits. In contrast, sulfate removal remains limited and variable, reflecting the inherent constraints of neutralization-based treatment processes. A moderate positive relationship
between monthly precipitation and generated mine water flow was identified (r = 0.5592, Pearson), enabling the development of an empirical regression model for predicting hydraulic loading. Based on this relationship, a three-tier hydraulic risk classification was proposed, incorporating a conservative safety factor to define operational thresholds under variable precipitation conditions. The proposed approach enables the use of forecasted precipitation as an early indicator of hydraulic load, supporting proactive and adaptive management of treatment facilities. The results highlight the importance of integrating monitoring and meteorological data to improve predictability, optimize resource use, and ensure stable system performance under changing climatic conditions.
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