Migration in a Single Fracture

It has been decided to investigate flow and sorbtion in a readily identifiable fracture which can be excavated for a detailed examination of flow path and sorbtion sites. The investigation is performed in the Stripa mine, 360 m below ground, where there is a natural water flow towards the drift. The bedrock is granite. A method of tracer injection into a fracture, either as a step or a pulse, and of collection of water samples under anoxic atmosphere has been suggested and tested in a preparatory investigation. The introduction of tracers can be done either under natural pressure or by injection with over pressure. An injection of Rhodamine-WT, Na-iodide and Na-Fluorescein with over pressure has been performed. It has been found that Rhodamine-WT is influenced in some way along the the flow path.