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San Xavier District Water Resource Issues
San Xavier District of the Tohono O’odham Nation
Asarco Mine Reclamation
• Waste facilities from open pit copper mining completed and needed to be reclaimed
• Mining began before federal environmental laws and reclamation standards were in place
• Mining company was reluctant to spend money to reclaim because of low copper price and delayed submitting a mine plan
• Bankruptcy forced Asarco to negotiate settlement to reclaim tribal lands
Tribal Involvement• Technical expertise needed to advise tribal parties on reclamation measures; both tribal staff and hired consultants
• Tribal staff represented San Xavier District on the panel authorized with expending the funds in the Settlement account
• Tribal technical staff took the lead in formulating plans and hiring consultants for technical investigations and QA inspections for reclamation work: preparation of RFP’s and contract management, etc.
Reclamation Funding
• Started with a settlement amount of $33 million
• Spent approx. $23 million on Tailings and Mission North Dump reclamation
• $3 million set aside for area not reclaimed until status of new lease is determined
Tailings Reclamation
• Covered tops of tailings with alluvium and seeded with native vegetation
• Re‐graded slopes, covered with alluvium, and then covered with rock
• Seeded some slopes
Waste Rock Dumps
• Waste rock was dumped in haphazard fashion
• Acid‐generating materials present
• No record of what was dumped with possible hazardous materials and substances present
• Waste rock dumped too close to the lease boundary
• Angle of repose slopes gave rise to erosion
Mission North Rock Dump Reclamation
• Re‐graded most slopes
• Covered tops with alluvium and seeded with native vegetation
• Covered acidic rock slopes with non‐acidic rock
• Seeded most visible slopes
San Xavier North Pit and Rock Dump
• Area has not been mined for 11 years
• Mining company is in process of negotiating new mining lease with the land owners
• Reclamation postponed until status of new lease is determined
• Technical expertise needed to advise tribal parties in negotiation process: environmental issues, value of ore body, and reclamation plan
Reclamation Maintenance
• Established $4 million account for future reclamation maintenance
• Currently drafting an agreement between the tribal parties for use of the reclamation maintenance account
• Maintenance issues: erosion, fence repair, damage from cattle and wild horses
Groundwater Issues
• Known sulfate contamination of groundwater from Asarco tailings ponds
• Possible uranium contamination from leachate from tailings and waste rock
• Arizona Department of Environmental Quality has no jurisdiction on Tribal lands and Federal government has no program in place to monitor groundwater on mined lands
Aquifer Protection Permit Intergovernmental Agreement
• Intergovernmental Agreement formed between ADEQ and BIA/BLM for Asarco’s Aquifer Protection Permit on tribal land
• ADEQ administers permit process
• BLM is enforcement agency
• Tribal representatives review and comment on APP application and related documents, and give technical input in negotiations and meetings
Water Management Plan
• Will provide a system to manage and account for use of CAP water, groundwater, and surface water
• Will set priorities for use of CAP water, groundwater, and surface water
• Will provide a plan for underground storage and recovery of CAP water for future CAP outages and shortages
• Will provide guidelines for management of groundwater quality affected by mining, farming, and CAP water use
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