Infiltration and Seepage Through Fractured Welded Tuff

Ghezzehei, T.A. and Dobson, P.F. and Rodriguez, J.A. and Cook, P.J.

Proceedings of the 11th International High Level Radioactive Waste Management Conference, IHLRWM , 2006.


The Nopal I mine in Pena Blanca, Chihuahua, Mexico, contains a uranium ore deposit within fractured tuff. Previous mining activities exposed a level ground surface 8 m above an excavated mining adit. In this paper, we report results of ongoing research to understand and model percolation through the fractured tuff and seepage into a mined adit both of which are important processes for the performance of the proposed nuclear waste repository at Yucca Mountain. Travel of water plumes was modeled using one-dimensional numerical and analytical approaches. Most of the hydrologic properly estimates were calculated from mean fracture apertures and fracture density. Based on the modeling results, we presented constraints for the arrival time and temporal pattern of seepage at the adit.