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Abandoned Mines:

Effects on stream water geochemistry. Abandoned Mines:. Fall, 2003 Serena NW Hollmeyer. Questions. What effects to abandoned mines have on pH and conductivity? What effects will abandoned mines have on dissolved metal species downstream? Where are the metals seen downstream coming from?

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Abandoned Mines:

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  1. Effects on stream water geochemistry Abandoned Mines: Fall, 2003 Serena NW Hollmeyer

  2. Questions... • What effects to abandoned mines have on pH and conductivity? • What effects will abandoned mines have on dissolved metal species downstream? • Where are the metals seen downstream coming from? • What impact does pH have on metal dissolution?

  3. Sample site locations: • Belvidere Asbestos Mine, Eden Mills, VT. • Ely Copper Mine, Vershire, VT. • MacIntyre Titanium Mine, Tahawus, NY.

  4. Belvidere Asbestos Mine • Eden Mills, VT. • Asbestos mine • 1960-1993 • Serpentine, amphibolite, muscovite schist. • Drains into Dark Branch and Gihon River

  5. Ely Copper Mine • Vershire, VT. • 1821-1950 • Weakly calcareous mica schist with amphibolite and acicular amphibolite. • Pyrite occurrences. • Drains into Schoolhouse Brook (Upstream and downstream samples)

  6. MacIntyre Titanium Mine • Tahawus, N.Y. • 1941-1982 • Ilmenite and magnetite • Drains into Opalescent River.

  7. Methods • Samples collected, filtered and acidified. • pH and conductivity measured using digital meters. • Samples analyzed using inductively coupled plasma optical emission spectrometer (ICPOES). • Looked for 24 different metals.

  8. Belvidere Data

  9. Belvidere Metals

  10. Ely data

  11. Ely metals

  12. MacIntyre data

  13. MacIntyre Metals

  14. Analysis: • pH was lowest at Ely (expected due to sulfidic mineral exposures increasing acidity) • Metals were most mobile at Ely, due to low pH? • Na, Ca, and Mg levels elevated at each site, related to bedrock weathering?

  15. Belvidere samples and possible sources of metals: Calcic filling of fractures? Amphibole Serpentine Road salt runoff?

  16. Ely samples and possible sources of metals. Calcareous bedrock Mica Copper ore Amphibole Road salt? Feldspar Associated iron ore

  17. MacIntyre samples and possible sources. Feldspar weathering (no road salt input) Ilmenite

  18. pH was lower at sulfidic site. Conductivity was highest in pit lakes or drainages Lower pH created conditions condusive to metals leaching Bedrock geology ultimately determined metals available for leaching. Bedrock geology also determined pH, the controlling factor in leaching of metals. Conclusions

  19. Questions?

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