Community Driven Science Reports on Background Water Contamination at the Homestake Barrick Gold Superfund Site, 2020

In 2018, the Bluewater Valley Downstream Alliance and the Multicultural Alliance for a Safe Environment hired two technical experts to provide an independent analysis of the Background Water Contamination Conceptual Model at the Homestake Barrick Gold Superfund Site. 

Community members have long stated that the contamination levels used by Homestake were misleading. Local neighbors and uranium miners know first hand where water was located at the site before the Uranium Mill was built in 1958.  

State and Federal agencies rely on the polluters to provide scientific information and rarely question the validity or assumptions in reports.

Our experts reviewed historical documents, interviewed local miners, reviewed maps and charts, and then developed two reports that directly challenged the background contamination levels at the Homestake Superfund Site.

Ann Maest, PhD, Buka Environmental

Summary

The groundwater protection standards (GWPS) established in 2006 for the Grants Reclamation Project Site (“current GWPS”) do not accurately reflect pre-mining/milling-influenced, background conditions because the standards are based on many sample results that reflect mining influence. This memorandum presents an alternative approach to calculating GWPS values (“proposed GWPS”) for the alluvial aquifer, the Chinle Mixing Zone (as a whole and separately for each section of the Chinle aquifer), and for each Chinle Non-Mixing Zone. A comparison of the results from the current and proposed GWPS values is shown in Table S-1.

You are read Ann’s full report here.

Tom Myers, PhD

Summary

The purpose of this technical memorandum is to propose defensible background concentrations for uranium (U) for the primary aquifers at the Homestake Millsite in Grants NM.  A background concentration is the concentration that occurred in the aquifers prior to mining and milling in the area.  The primary contamination source is the large tailings pile (LTP) created at the Grants mill.  I used historic concentration data from a Homestake Mining Company data to estimate background..  Data subject to trends or to concentration spikes were not used because this is evidence of impacts.  Concentrations that have returned to much lower levels after high spikes may be considered background if the spikes could be linked to temporary leakage.

You can read Tom’s full report here.