Novel lab tool for paste backfill

The application of paste backfill technology for mined stopes has been a major contributor to the development and economic growth of mining industries across the world, and hence to a reduction of the environmental impacts of surface tailings storage. The design aspect of cemented paste backfill (CPB) is most often based on material that is prepared, cured and tested in a lab. However, the lab curing conditions are well proven to be different from field conditions. A proper lab system for assessing the effects of consolidation and drainage conditions could greatly help the laboratory simulation of field conditions.

A mining engineering research team at the University of Quebec in Abitibi-Temiscamingue (UQAT) has recently developed novel lab equipment called the Curing Under Applied Pressure System (CUAPS) that allows for more confident determination of pertinent mine fill properties at lab scale. This equipment can be used to simulate CPB placement and curing processes, and then to assess the strength development of the samples under consolidated and drained conditions via the application of external pressure on the fill sample top.

The operating principle of the CUAPS apparatus, as shown in the illustration, is based on the axial compression of a paste backfill sample in the chamber. The development and manufacture of the CUAPS equipment (a total of 10 set-ups) has been financially supported by the Canadian Fund for Innovation.

This novel equipment has been used for testing CPB samples made from both European and Canadian mine tailings. The set-up exhibits good time-dependency sensitivity in capturing the CPB samples’ change under a variety of loading and drainage conditions. Although the CUAPS apparatus is at the first stage of development and may need to be modified depending on applications, so far it has been found to be faster, more practical, and more cost-effective than the conventional approach using plastic moulds.

Further information about the CUAPS equipment and results of case studies involving some projects can be requested from the authors.

Dr. Mostafa Benzaazoua (Mostafa.Benzaazoua@uqat.ca) and Dr. Tikou Belem (Tikou.Belem@uqat.ca) are professors of mining engineering at the University of Quebec, Rouyn-Noranda, Quebec, J9X 5E4. Erol Yilmaz (Erol.Yilmaz@uqat.ca) is a Ph.D. student in the same department, tel. 819-762-0971 ext 2539.