Groundwater is introduced through a stainless steel
inlet port by an HPLC (High Pressure Liquid Chromatography)
pump (Younglin 930 M) so that it can flow
through the artificial fracture between the two halves of
the granite core. A stainless steel outlet port is also installed
at the end of the column and it is connected to a
fractional collector (Foxy Jr., ISCO). The inlet and
outlet ports are pressed by stainless steel joints to hold
the granite core and the ports tight. Samples of 80 drops
(about 4.0 mL) are collected periodically by the fractional
collector to determine the size and concentration
of the eluted bentonite particles.