ENFORCE26825 - Laserfiche WebLink

Home Browse Search

Memo to Oehler BMRI Abatement tt8 Submittal page 3 In reviewing the tent, figures and "Tailings Sample Hole Logs" con ained within the report, I am concerned that BMRI sampling of the pre- iolation tailings was limited to shallow hydrogen peroxide exposed tails in the Upper Pond. Only hole #8 may have penetrated the uppermost foot of A R treated tails in the Lower Pond, and these tails may also have been genet ated by hydrogen peroxide tgreated fluids subsequent to deposition and p for to sampling. Further, only hole ~7 appears to have penetrated the TOX bearing tails in the Lower Pond. All the other holes, and the samp es obtained from them, appear to be limited to the tailings deposited during the application of hydrogen peroxide to the Lower Pond. As a result 1 am concerned that the sampling performed does not represent the en irety of the tailings in place. In fact the pre-violation, AVR-treated tails h ve gone largely unsampled. In addition ,the shallow samples which were btained in both ponds may have been exposed to hydrogen peroxide treat d fluids prior to their collection and analysis. Both PASS and Dr. Posey ha expressed similar concerns regarding whether BMRI adequately o representatively sampled the tails. I do not believe that this necessarily invalidates any of the work c mpleted so far. However, at a minimum, BMRI will have to complete samp 'ng of the appropriate tailings materials. Obviously, a different sample cone lion method andfor apparatus wilt have to be used. In my opinion, at east two holes should be completed in each of the tailings ponds. These hot s should sample the entire tailings section to five feet above the liner. This should also provide opprtunity to collect adequate in-situ fluid samples to define the character and distribution of tailings fluids throughout the tail' gs. Finally, BMRI should evaluate the relationship of the three-dimen 'onal tailings constituency to the samples which have previously underg ne extensive laboratory analysis. If the supplemental sampling deter Ines that the materials previously exhaustively analyzed were representativ e of the tailings mass then no additional laboratory analysis would be nece sary. If not, additional analysis will need to be completed. I do not believe this determination can be completed at this time. BMRI is simultaneously seeking approval to commence constructio of its first of two proposed up-valley tailings embankment raises. In an icipation of this construction, tailings deposition will be occurring in the Up r Pond. BMRI will mobilize an earthwork contractor to construct the raise i multiple