Mineralogical and chemical characteristics of the bentonite in the A2 test parcel of the LOT field experiments at Äspö HRL, Sweden

► Field test with Wyoming bentonite at the Äspö Hard Rock Laboratory at 500 m depth. ► Temperatures of up to 130 °C for almost 6 years. ► Chemical and mineralogical analyses of bulk and clay fraction material. ► Mg content and CEC gradients with peak values at the heater. ► Redistribution of sulphate minerals with anhydrite precipitation.