Presented at the SME Annual Conference, February 16 2015. Over the past few decades, mines have increasingly included closure early in the planning process. Environmental goals may be reasonably clear, even prescriptive. Sites that came into operation before the modern era, though, don’t have the benefit of early planning for closure. Goals often aren’t set until late in the mine life, perhaps decades after operations cease in many cases. What are the acceptable goals for those sites? What can we achieve, then sustain over the long term? Answers to these questions form very site-specific goals for closure at each legacy site.

1. Acceptable, Achievable,
Sustainable? Assessing Closure
Goals at Legacy Mine Sites
Walter Weinig
February 16, 2015
SME Annual Conference

2. Begin with the End in Mind
—Stephen Covey
The End is Nigh…

3. Legacy Mine Sites
Active, older properties
Inactive
Abandoned

4. Modern vs. Legacy
Modern Legacy
Plan for Closure Yes No
Closure Period Defined Unclear
Regulations Usually Unclear
Financial Assurance Yes Maybe
Responsible Party Company Varies

5. Evaluating Goals
Acceptable?
Achievable?
Sustainable?

6. Acceptable?
Multiple Stakeholders, Multiple Views
• Regulators
• Local community
• NGOs
• Corporate standards
6

7. Achievable?
• Technically practical
• Pre-existing conditions
• Implementation time frame
7

8. Sustainable?
• Financing, responsible party
• Community capacity
• Bias toward passive, natural systems
• “In perpetuity”
8

9. 9
Case Studies

10. Wellington-Oro
Wellington Oro circa 2002, from
U.S. EPA
Wellington Mine, 1909
From USGS archives

11. Wellington Oro
• Point of compliance in receiving stream to
protect aquatic life, fishery
• Active treatment in relatively developed
area by mining standards
• Treatment plant operated by town
11

12. Tiger
& Jessie
Denver Public Library archive

13. Tiger & Jessie Mine, Mill
• Natural wetlands attenuate metal concentrations
before outflows reach stream
• Remove mill tailings from stream banks for source
control
• Stabilize historic mill, administrative controls
• Attraction along hiking trail in county open space
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14. Somewhere in the West…
100+ years of mining
Identified groundwater impacts
Mix of operating, inactive, and abandoned
mines

15. Somewhere in the West…
• Standards complicated by overlapping
regulatory programs
• Source control: grading, hydraulic barriers
• Active groundwater pump & treat
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16. Somewhere Else…
Historic mining district
Possibly re-opening existing mine
Legacy facilities vs. new requirements

17. Somewhere Else…
• Define existing impacts as basis for
standards related to new development
• Proposed new construction on top of
historic facilities
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18. Legacy Pit Lakes
Photos courtesy of Dr. Glenn Miller,
University of Nevada

19. Legacy Pit Lakes
• Neutral vs. acidic conditions
• Appropriate standards – aquatic life,
terrestrial wildlife, human contact
• Access for treatment can be difficult
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20. Legacy Mine Closure Goals Summary
• Acceptable? Stakeholder opinions may vary
• Achievable? Different constraints, existing
conditions
• Sustainable? Financing, operational
responsibility, time frames
• Each site is unique, but solutions can be found