There are risks associated with structural failure, seepage and dust. The biggest risk is structural failure, which may arise from various factors such as intense rainfall, seismic activity, inadequate engineering calculations, and insufficient monitoring.
The structural failure process begins if the TSF filter cracks. At Oyu Tolgoi, engineers and technicians monitor the TSF every day to see if there are any cracks. If there is one, they continuously monitor and measure it every day. If necessary, they will reconstruct the area to prevent damage.
There is also continuous monitoring during TSF construction and once its ready to operate around 400 monitoring tools are used to monitor for 24 hours. This is done to predict, detect many potential risks, and monitor the risk of dam failure.
The tailings, characterized as a slurry, continually seeps when it interacts with the TSF structure. If there can’t be seepage, the accumulated water increases the pressure on the walls of the dam and increases the risk of dam failure. If the seepage is not monitored there’s risk of it being released into the environment.
Therefore, at Oyu Tolgoi, an 8-12-meter-deep cut-off dyke was built to reduce the base seepage. To prevent seepage from being released into the environment, a collection system is situated beneath and outside the Tailings Cell. The collected seepage is then recycled.
Large amounts of dust can harm human health and the environment. Oyu Tolgoi’s TSF manages its dust through multiple pipelines efficiently disposing of the waste and the area is kept moist to control dust. When the TSF’s operation reaches the end, the land undergoes a closure process, including rehabilitation and covering the waste to prevent dust-related impacts.