Montgomery & Associates

This technical memorandum has been prepared to summarize results of drilling, construction, and testing at hydrologic test wells DHRES-12 and DHRES-13. Borehole DHRES-12 was drilled to characterize hydrogeologic conditions in the deep groundwater system in Cross Canyon, west of the Apache Leap escarpment, and to provide a monitoring location for the deep groundwater system during ongoing dewatering operations. DHRES-12 was abandoned prior to completion due to lost circulation and borehole instability. Well DHRES-13 was drilled at the same site to replace abandoned borehole DHRES-12.

This technical memorandum was prepared to summarize results of drilling, construction, equipping, and testing at hydrologic test wells DHRES-03, DHRES-04, and DHRES-05/DHRES-05B. The wells were installed to characterize hydrogeologic conditions in the Gila Conglomerate and Apache Leaf Tuff west of the Concentrator Fault in the vicinity of West Plant site and to provide monitoring locations for the aquifer west of the Concentrator Fault during dewatering operations in 2010 and 2011.

This technical memorandum was prepared to summarize results of drilling, construction, equipping, and testing at hydrologic test well DHRES-06. The well was installed to characterize hydrogeologic conditions in the deep groundwater system south of the South Boundary Fault and to provide a monitoring point for the deep groundwater system during dewatering of existing mine workings. Monitoring data obtained from DHRES-06 will be incorporated into the RCM hydrologic monitoring program.

This technical memorandum was prepared to provide an interim summary of data collected at wells DHRES-01 and DHRES-02. Deep hydrogeologic test wells DHRES-01 and DHRES-02 were drilled and constructed during the period May 2 to September 10, 2008. In order to measure hydraulic heads at specific elevations in the Apache Leap Tuff (Tal) and Whitetail Conglomerate (Tw), vibrating-wire pressure transducers were grouted in the annulus between the borehole wall and conductor casing at wells DHRES-01 and DHRES-02.