Air Sciences

The purpose of the CIA is to quantitatively evaluate cumulative air quality impacts due to emissions from the Project and reasonably foreseeable and known sources of emissions in the region near the Project. The identified nearby sources, modeling methods, and results of the CIA are presented in this technical memorandum.

This screening level assessment of human health risk associated with air emissions from the proposed Resolution Copper Mine (Project) is based on exposure calculations and reasonable and conservative assumptions, as summarized here:

Response to US EPA comment #524-20, "While the Draft EIS relied on [a dispersion] analysis contained in the Resolution Copper Project NEPA Air Quality Impacts Analyses, we are concerned that it may have underestimated PM10, as well as PM2.5, emissions.[...]"

Response to comment #278-5 from ADEQ, "The most recent 3 years of [air quality] monitoring data show that the concentration levels in Year 2017 were higher than previous years. However, the NEPA Air Quality Impacts Analyses does not consider the 2017 monitoring data for the background concentrations determination. Would it be a concern?"

In order to address specific matters included in comments on the DEIS, the TNF has requested more specific information pertaining to reasonably foreseeable HAPs emissions and, as applicable, associated potential health effects.

This Modeling Report includes a description of the methods and datasets used in the air quality modeling analyses to estimate the Resolution Project’s air quality impacts relative to the applicable Ambient Air Quality Standards (AAQS) for criteria pollutants and to Air Quality Related Values (AQRV) in the near-field domain and in several Class I Wilderness Areas in the far-field domain.

This Modeling Report includes a description of the methods and datasets used in the air quality modeling analyses to estimate the Resolution Project’s air quality impacts relative to the applicable Ambient Air Quality Standards (AAQS) for criteria pollutants and to Air Quality Related Values in the near-field domain.

This modeling plan includes a description of the methods and data sets that are planned to be used in the air quality modeling analyses to estimate the Resolution Project’s air quality impacts relative to the applicable Ambient Air Quality Standards (AAQS) for criteria pollutants and to Air Quality Related Values (AQRV) in the near-field domain.

This Modeling Plan includes a description of the methods and data sets that are planned to be used in the air quality modeling analyses to estimate the Resolution Project’s air quality impacts relative to the applicable Ambient Air Quality Standards (AAQS) for criteria pollutants.

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Email Address Created for Land Exchange Questions

The Southwestern Region Office of Lands and Minerals Management is overseeing and administering the land exchange and appraisal process which includes the 2,422-acre Oak Flat Federal Parcel. All questions about the land exchange and appraisal process should be emailed to SM.FS.rcexinfo@usda.gov

Objection Period Ends March 1

Interested parties who previously submitted formal comments about the project have until March 1 to file an objection to the Tonto’s proposed decision.

For more info, view TNF News Release.

Programmatic Agreement Info

To comply with Section 106 of the National Historic Preservation Act, the Tonto National Forest developed a Programmatic Agreement (PA) and included it in Volume 5, Appendix O of the final EIS. The PA was created in cooperation with the Advisory Council on Historic Preservation, the State Historic Preservation Office, tribes and other consulting parties. The PA contains an agreed upon process for identifying, evaluating and addressing adverse effects to historic properties associated with this undertaking.

To review Volume 5 and the PA, Download Vol 5 PDF, 27 MB.

Forest Service Point of Contact

John Scaggs
Tonto National Forest
john.scaggs@usda.gov

Apache Leap Special Management Area
Apache Leap SMA website