1. Historical Mining and Water Quality in the Upper Animas Basin
Peter Butler, Ph.D.
August 23, 2017

2. Silverton and the Volcano

4. Early Mining Mining Began around Silverton in 1870’s
Downstream Towns Founded as Supply Towns
Narrow Gauge Railway 1882
Mining Heyday – late 1890’s
thru 1910

5. Downstream Impacts Pollution Generated in Durango Mill Tailings Dumped
in the River
Durango Switched to
Florida River For
Water Supply in 1902.

6. Early 1930’s Many Mines Shut Down Permanently Although Some Reopened
During WWII
Mining Companies began
Use of Tailings Ponds

7. Mining in 1950’s and Beyond
Very Little Mining through Most of the 1950’s.
The Old Gold King Tunnel (aka the American Tunnel) Was Extended Over a Mile Underneath Lake Emma and the Sunnyside Mine in late 1950’s, early 1960’s.
Sunnyside Mine Shut Down in 1991 and Mining Ceased.

8. Water Quality Issues – 1970’s and 1980’s.
Clean Water Act Passed in 1972.
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Passed in 1980.
Colo. Starts to Require Reclamation Plans and Bonds in Mid 1970’s.
Sunnyside Installs Treatment at American Tunnel in Late 1970’s, Upgraded in Early 1980’s.

9. Water Quality Issues – 1970’s and 1980’s.
Tailings Pond Failure in 1974.
Lake Emma Collapse in 1978.

10. 1990’s – Remediation Begins
Animas River Stakeholders Group (ARSG) Started by CDPHE in 1994.
WQCC Holds Hearing in Silverton
in 1994.
Dept. of Interior Begins
Abandoned Mine Land
Initiative in 1997
Sunnyside Gold Corp. and CDPHE
Sign Consent Decree in 1995

11. Study and Evaluation
Almost 200 Draining Mines Are Sampled and Prioritized for Remediation.
Almost 200 Mine Waste Piles Are Sampled and Prioritized for Remediation.
33 Draining Mines and 32 Waste Piles Account for 90% of the Mining-Related Metal Loading
ARSG Proposes (and WQCC Adopts) Water Quality Standards Based on Remediating Top Sites

12. Acid Mine Drainage

13. Mine Waste
Acid Rock Drainage
(Prospect Gulch)

14. Remediation and Water Quality
About 60 Mine Remediation Projects Have Been Completed Ranging from $10,000 - $2 Million.
Water Quality in Early 2000’s Was Probably the Best in 100 Years.
Fish and Macroinvertebrate Studies Support Water Quality Data.

15. Koehler Tunnel
Before
After

16. Infiltration Control Project
Before
Pride of West Stope
Infiltration Control Project
Stream
Avalanche Path
Constructing
Finished

17. Koehler Bulkhead

18. Water Quality Worsens
By Mid 2000’s, Water Quality and Correspondingly Fish and Macros Became Much Worse Directly Below Silverton.
All Water Quality Stds. Continue to Be Met at Trimble Lane.
Issues Arise with Previously Permitted Sites.

20. Other Important Points
After Bulkheads but before the Gold King Release, Four Portals (Gold King, American Tunnel, Red & Bonita and Mogul) Had the Approximate Metal Load (lbs/Day) of all the Other Draining Mines (~180) in the Basin.
Before the Release, the Gold King Flow Was around gpm. Afterwards about gpm which is being treated.

21. Other Important Points
Water Quality Meets All Quality Standards for the past 25 Years (Except for the Secondary Manganese Drinking Water Standard) at Trimble Lane.
Water Quality Has Improved over the Last Five Years Compared to Five Years to Ten Years Ago.

22. Superfund Designation
Many of the 46 Sites Identified in the Superfund District Came From ARSG’s List Plus the Main Gladstone Mines.
There are Two Study Areas – The Sunnyside Mine Pool and Prospect Gulch.
Only 19 Sites Were Given a Hazardous Ranking Score.