1. Metal Loading to the Animas River
Animas River Stakeholders Group
February 23, 2016

2. Metal Loading at the Four Gages
Used 2012–2014 data. Metal loading was quite a bit less than There was 20%+ less flow in the river in
Used the average concentration of samples taken each month over a three year period multiplied by the average daily flow for the month during the three year period. Some months only had one sample per month per year (Used 3 samples for the month).
Used total recoverable for Fe and Al, but only the dissolved fraction for Zn and Cd.

3. Only examined zinc, cadmium, iron and aluminum which have concentrations above standards at Bakers Bridge. Other metals of concern, lead, copper, and manganese, are potential problems in smaller areas.
Loads in May are probably inflated. Samples taken early in the month when flows are lower and concentrations higher, then multiplied by higher, average flows.
This analysis could be significantly more refined, but it gives a rough picture of loads (in lbs/day of individual metals).

8. Mining-Related Metal Loading:
Can only make broad generalizations.
Compare loading from mining sources measured in the 1990’s to
Used 80% reduction of metals from remediated sites.
Averaged mine waste load from April-Sept.

9. Mining-Related Metal Loading: Mineral Creek (M34)
Most of the remaining Zn and Cd is mining-related except possibly late spring and early fall. Most is from adits, little from waste rock, except perhaps late spring and early fall.
Insignificant amount of Al is mining-related.
Less than half of Fe is mining-related, but not insignificant.

11. Mining-Related Metal Loading: Cement Creek (CC48)
Very similar to Mineral Creek.
Most of the remaining Zn and Cd is from adits, little from waste rock. The exception is possibly late spring and early fall.
Little of Al is mining-related.
Less than half of Fe is mining-related, but not insignificant.

12. Mining-Related Metal Loading: Animas above Cement Creek (A68)
Did not estimate loading from Mayflower tailings, Howardsville mill, or Eureka floodplain.
Al, Zn and Cd, less than half from measured mining-related sources. Significant (but less than half) only in winter.
Much of Fe is from mining-related sources, but little Fe overall.