Orano’s operation in Kazakhstan is a great example of where progressive closure is being used to reduce closure liability costs and reduce environmental, social and reputational risks. Progressive closure is the implementation of closure activities during operations and is an effective way of building a knowledge base to understand the site specific factors affecting final closure. Element 5 of ICMM's 'Integrated Mine Closure: Good practice guide' provides more information on closure activities, progressive closure and achieving final closure.
A joint venture created in 1997 by The Orano Group and Kazatomprom in Kazakhstan, KATCO operates the world’s first and largest in situ recovery (ISR) uranium mine. KATCO is situated near the village of Taukent in the Turkestan region; with annual production at around 4,000 tonnes, it has produced over 40,000 tonnes of uranium since 2006.
The ISR recovery principle consists of injecting an acidic solution into the ground to selectively dissolve the uranium deposit. The solution containing the uranium is then pumped to the surface and transported by pipeline to the processing plant where the uranium is extracted and concentrated. Once stripped of uranium, the acidic solution is re-injected into the wells, continuing the closed-circuit process.
ISR technology has evolved with tight operational and regulatory controls. It causes little surface disturbance, does not generate tailings or waste rock, and requires less investment than conventional mining. However, because the native groundwater (naturally with an industrial quality) is used in the ISR process, closure of ISR sites requires the quality of the groundwater to be restored to a standard determined before the start of the operation, so that any prior use can be resumed.
In 2011, KATCO launched an ambitious research and development programme to assess if groundwater could be restored to pre mining quality through natural attenuation. Natural attenuation means using a variety of physical, chemical and biological properties naturally occurring in the groundwater to reduce the amount and concentration of contaminants without human intervention. Ongoing monitoring is required to verify the processes are effective and can accelerate the remediation of groundwater tested on site.
The rehabilitation programme developed by KATCO for the entire well field was approved by the authorities of the Republic of Kazakhstan – the process started while operations are still in progress and include closing wells, restoring the well fields, restoring the mill area. Upon reaching the end of its cycle, KATCO will implement environmental monitoring of the reclaimed site until the restored locations are returned to the Republic of Kazakhstan. A detailed cost assessment for closure was also completed in 2019 through the liquidation project in accordance with the new Kazakh mining regulation.