Diffusion in the Matrix of Granitic Rock: Field Test in the Stripa Mine

Three field experiments in granitic rock were performed at 360 m depth in a mine to investigate diffusion in the undisturbed rock matrix. The results from all three experiments showed that tracers had migrated through the disturbed zone close to the injection hole and a distance into the undisturbed rock matrix. These results show that it is possible for dissolved compounds to migrate into the rock matrix in its natural stress environment. Diffusivities and hydraulic conductivities obtained in this in situ experiment compare well with those obtained in laboratory experiments.