Zelazny Most mine tailings dam
To ensure the safe operation of the tailings dam at Zelazny Most, NGI has assisted the mining company KGHM Polska Miedz with advanced stability analyses of the dam structure and associated ground. Various measures to stabilize the dam surface have also been evaluated.
The world needs copper. However, extracting copper on a large scale generates enormous volumes of residual material from mining operations, placed in huge deposits called tailings dams. Over the years, such dams may take on enormous dimensions in height and area. This may cause huge settlements and local slides, and in the worst case, disastrous huge slides with devastating destruction and potential contamination from the tailings material.
The Zelazny Most tailings dam was 63 meters high in 2017, with a circumference of almost 15 km, and grows 1.5 meters higher every year due to deposition of new tailings material from the nearby mining activity
KGHM Polska Miedz, operates three mines in southwestern Poland. Tailings are pumped into an artificial lake, Zelazny Most. The dam that surrounds the lake is the largest in Europe and one of the largest in the world. The dam was 63 meters high in 2017, with a circumference of almost 15 km. Tailings from the operation of three subterranean mines and associated smelting plants are pumped into the dam. The dam grows 1.5 meters higher every year, creating major challenges for the stability of the entire plant and the surrounding area. KGHM is extremely concerned about safety.
Advanced analysis and monitoring
To ensure the safe operation of the dam at Zelazny Most, NGI provides the mining company with continuous advanced analyses and calculations of the dam structure and associated ground. The dam's stability has been analyzed over several years to predict how it moves laterally. KGHM wishes to continue extracting copper for another 40–50 years. To do this safely, thorough monitoring, correct analysis, and stabilizing measures are crucial.
Various measures to stabilize the dam surface to prevent slippages have been evaluated. One possible measure is to construct deep, vertical support shafts that can hold the tailings in place. Other possibilities are drainage wells, berms, supporting embankments, and retaining walls.
NGI assists the mining company by analyzing the effects of various proposals for stabilizing measures to ensure that the dam can be used many years into the future.
Ana Page Riseueno (left) has been one of the NGI project engineers working on Zelazny Most. Lars Andresen, CEO of NGI (left) and Kaare Høeg, member of the independent International Board of Experts, visiting Zelazny Most in the southwest of Poland in 2017 (Photo: NGI)