1. Hydrologic Investigation Summary
Prepared at the Request of
Nevada Division of Environmental Protection -
Bureau of Mining Regulation & Reclamation
February 2009
Errol L. Montgomery
& Associates, Inc.

2. Site Location
Errol L. Montgomery
& Associates, Inc.

3. Errol L. Montgomery
& Associates, Inc.

4. ANNUAL PRECIPITATION
Errol L. Montgomery
& Associates, Inc.

5. MONTHLY PRECIPITATION
Errol L. Montgomery
& Associates, Inc.

6. Geologic Map
Errol L. Montgomery
& Associates, Inc.

7. Site History Mercury mining 1915 to 1940s Inactive from 1940s to 1960s
Exploration by numerous companies for gold and other commodities 1960s to 1980s
Open pit / heap leach mining by Touchstone Resources and Galactic Resources joint venture 1990 to 1992
Errol L. Montgomery
& Associates, Inc.

8. Site History (cont.)
Operation of heap leach and exploration by Newmont 1992 to 1995
Closure / reclamation by Newmont 1996 to 1998 (Water Pollution Control Permit NEV88022)
Errol L. Montgomery
& Associates, Inc.

9. Site History (cont.) Exploration by Great Basin Gold 1997 to 2002
Underground exploration by Hecla Ventures 2002 to 2007 (Water Pollution Control Permits NEV & NEV )
Ongoing underground exploration by Great Basin Gold / Rodeo Creek Gold 2007 to present (Water Pollution Control Permits NEV & NEV )
Errol L. Montgomery
& Associates, Inc.

10. Monitoring Network
Touchstone/Galactic wells early 1990s (WW-1 and WW-5)
Newmont wells 1998 and 2000 (HOL-MW1, P1 and P2)
Hecla Ventures wells 2002 and (BH-series, W-E-1, and DGW-1R)
Rodeo Creek Gold wells 2006 and 2007 (red) and surface water monitoring sites (green)
Errol L. Montgomery
& Associates, Inc.

11. Monitoring Program Quarterly Groundwater Levels
14 monitor wells
1 water supply well
7 piezometers
West Pit pond
Quarterly Groundwater Quality Samples
13 monitor wells
2 water supply wells
2 piezometers
7 stream sampling locations
Errol L. Montgomery
& Associates, Inc.

12. Occurrence of Groundwater
Groundwater occurs in two fractured rock aquifers
Tertiary volcanic rocks
Ordovician sedimentary rocks
Errol L. Montgomery
& Associates, Inc.

13. Volcanic Rock Aquifer
Groundwater in the Tertiary volcanic rocks is recharged locally by precipitation
Groundwater level in the Tertiary volcanic rocks follows local topography
Groundwater movement in the Tertiary volcanic rocks is from the north-northwest toward the south-southeast
Errol L. Montgomery
& Associates, Inc.

14. Sedimentary Rock Aquifer
Groundwater in the Ordovician sedimentary rocks is recharged in the mountains to the northeast
Groundwater movement in the Ordovician sedimentary rocks is from the northeast toward the southwest
Errol L. Montgomery
& Associates, Inc.

15. Location Map
Errol L. Montgomery
& Associates, Inc.

16. BH-07
Errol L. Montgomery
& Associates, Inc.

17. BH-01
Errol L. Montgomery
& Associates, Inc.

18. Location Map
Errol L. Montgomery
& Associates, Inc.

19. Errol L. Montgomery
& Associates, Inc.

20. Location Map
Errol L. Montgomery
& Associates, Inc.

21. Water Level Comparison
Errol L. Montgomery
& Associates, Inc.

22. April 2008 Groundwater Contours
Errol L. Montgomery
& Associates, Inc.

23. Groundwater Quality
Up-gradient groundwater quality--background levels Tertiary volcanic aquifer and Ordovician sedimentary aquifer
Pit area water quality--impacted by historic mining operations
Down-gradient water quality--slightly impacted by historic mining operations
Errol L. Montgomery
& Associates, Inc.

24. Stiff Diagram Well Identifier pH Date Sampled Total Dissolved Solids
Na + K Ca Mg Cl
HCO3
SO4
Date Sampled
Total Dissolved Solids
milligrams per liter
Errol L. Montgomery
& Associates, Inc.

25. Groundwater Quality Up-gradient from Historic Mining Operations
Tertiary volcanics
Ordovician sediments
Errol L. Montgomery
& Associates, Inc.

26. Groundwater Quality Vicinity of Historic Mining Operations
*Pit area well
Errol L. Montgomery
& Associates, Inc.

27. Groundwater Quality Down-gradient from Historic Mining Operations
Tertiary volcanics
Ordovician sediments
Down-gradient well
Errol L. Montgomery
& Associates, Inc.

28. Location Map
Errol L. Montgomery
& Associates, Inc.

29. Surface Water Quality Up-gradient from Historic Mining Operations
Upstream
Errol L. Montgomery
& Associates, Inc.

30. Surface Water Quality Vicinity of Historic Mining Operations
Upstream from East toe
East toe
Downstream from East toe
South toe
Errol L. Montgomery
& Associates, Inc.

31. Surface Water Quality Down-gradient from Historic Mining Operations
Little Antelope Creek
Downstream
*Downstream
Antelope Creek
Errol L. Montgomery
& Associates, Inc.

32. Sulfate Concentrations/pH April 2008
Errol L. Montgomery
& Associates, Inc.

33. Sulfate Concentrations
Errol L. Montgomery
& Associates, Inc.

34. Water Quality Comparison 1996 and 2008
Errol L. Montgomery
& Associates, Inc.

35. Conclusions Site is well characterized
Surface and groundwater monitoring data indicate that impacts are related to historic mining operations
Monitoring data also show that state-of-the-art (and unique to Nevada) engineered waste rock storage facility and stormwater management features are not contributing  impacts to surface and groundwater
Closure / reclamation efforts continue
Errol L. Montgomery
& Associates, Inc.