Project Description III

Litigation Support and Expert Witness Testimony
Acid Mine Drainage Cleanup
Central Arizona

Project Description: The Source Group is providing litigation technical support and serving as an expert witness, supplying opinions regarding cost recovery and future apportionment among several responsible parties for cleanup of a large acid mine drainage site in Arizona.

The case has been filed under CERCLA provisions and is being heard in the Federal court system. A comprehensive analysis of the site hydrogeology and mining activities has been conducted in support of water budget modeling performed as part of an assessment of the relative contributions to the acid plume by various responsible parties.

The modeling entailed a detailed representation of a tributary alluvial groundwater flow system over a period of 90 years. Time-varying hydrogeologic stresses (i.e., withdrawals resulting from pumping and evapo-transpiration, and inputs related to tailings pile draindown and precipitation recharge) were included in the model. Deposition testimony was recently given.

Results: The hydrogeologic work and recent deposition testimony by The Source Group has, in conjunction with geochemical work and related testimony by others, presented a physically-based set of arguments for cost allocation in this ongoing case. Court testimony is pending.