Exploration of Gaomiaozi bentonite deposit and excavation of the natural sodium bentonite

Gaomiaozi(GMZ) bentonite had been chosen as the candidate buffer/backfill material for high-level radioactive waste(HLW) disposal in China through a national screening and selection.In recent years, a large number of laboratory tests and theoretical analysis had been conducted on natural GMZ sodium bentonite.New sodium bentonite powder is needed to insure the continuity of the research.Three boreholes were drilled to reveal and verify various parameters, and it is found that the quality of sodium bentonite between exploratory lines 8-24 is good and stable, which conform to the previous exploration data.Open pit mining was employed to excavate sodium bentonite through a comparison taking into account the quality, thickness of bentonite layer, geological condition, etc.of two targeted locations.Preliminary processing and purification was adopted to improve the quality of excavated sodium bentonite.Through this work, natural GMZ sodium bentonite samples was successfully excavated, which is essential to the buffer/backfill material research work in the next 5 to 10 years.