2008-0816-MB

SUBJECT: The U.S. Army Corps of Engineers is requesting an opinion from the Advisory Council on Historic Preservation (“Council”) regarding the determination of no adverse effect to historic properties from the proposed Sonoita Creek Ranch Compensatory Mitigation Site.

AUTHORITIES: This Department of the Army (DA) permit application is being evaluated under Section 404 of the Clean Water Act for the discharge of dredged or fill material in waters of the United States. The request from the Council is in accordance with 36 CFR 800.5(c)(3) and the Corps’ Revised Interim Guidance for Implementing Appendix C of 33 CFR Part 325 with the Revised Advisory Council on Historic Preservation Regulations at 36 CFR Part 800.

APPLICANT:

Rosemont Copper Company

5255 East Williams Circle

Suite 1065

Tucson, Arizona 85711 

LOCATION: The Sonoita Creek Ranch Compensatory Mitigation property is located along State Route 82 northeast of Patagonia and southwest of Sonoita in Santa Cruz County, Arizona (Vicinity Map 487 KB and Site Map 320 KB).

PROJECT BACKGROUND AND PROPOSED PROJECT DESCRIPTION: The Rosemont Copper Project (“Project”) is located approximately 30 miles southeast of Tucson, Arizona, within unincorporated Pima County. The proposed project area would encompass approximately 900 acres of private land owned by Hudbay Minerals, Inc. (“Hudbay”) and 3,328 acres of National Forest land within the Coronado National Forest (CNF). A total of 5,431 acres of land would be disturbed as a result of proposed project activities (including the mine, primary access road and utility line corridors, road disturbance, and realignment of an historic trail) and a total of 6,990 acres would be excluded from public access by a perimeter fence. Hudbay Minerals, Inc. acquired Augusta Resource Corporation, including Rosemont Copper Company in September, 2014 and is the current owner of Rosemont Copper Company. Rosemont Copper Company continues to be the applicant.

The U.S. Forest Service was designated as the lead federal agency for compliance with the National Environmental Policy Act (NEPA), Section 106 of the National Historic Preservation Act (NHPA), and tribal consultation for the Project. The Corps has participated in the NEPA, NHPA, and tribal consultation processes as a Cooperating Agency and is also a Signatory to the Memorandum of Agreement (MOA) that was executed in 2013 to mitigate adverse effects to historic properties from the Project. Additionally, the Corps has met with concerned tribes and participated in a site visit with tribal leaders.

As part of Project-related compensatory mitigation requirements associated with the DA permit application review process, the applicant chose to acquire four parcels of private land within the Santa Cruz River  watershed. Because this location is beyond the limits of the proposed mine site and the mitigation plan was substantially revised since the signing of the MOA, the Corps assumed the role of lead federal agency for compliance with Section 106 of the NHPA.

DETERMINATIONS: In 2017, the Corps consulted with the Arizona State Historic Preservation Officer (SHPO) and all other consulting parties identified per the MOA regarding our determination of no adverse effect to historic properties from the proposed scope of work at the Sonoita Creek Ranch compensatory mitigation site. The archaeological sites and components recorded in the Area of Potential Effects (APE) and evaluated as part of this consultation include prehistoric, protohistoric, and Early Historic Native American resource procurement/processing and habitation activities, as well as Historic period Euro-American habitation, agriculture,  transportation, and utility land-use. The seven archaeological sites determined eligible for inclusion in the National Register of Historic Places (i.e. historic properties) include a former grade of the New Mexico & Arizona Railroad, an abandoned alignment of State Road (SR) 82, a complex of mounded earth features associated with a scatter of historic artifacts, a scatter of historic artifacts associated with structural elements and midden areas, and three protohistoric/historic Sobaipuri sites.

The Corps’ initial determination of no adverse effect to historic properties in 2017 was based on the fact that all but the abandoned alignment of SR 82 would be avoided by construction activities at the Sonoita Creek mitigation site. In regard to the abandoned alignment of SR 82, two features will be impacted, but both are common features (i.e., a culvert and a bank protection) that do not, in themselves, contain the kinds of information that contributes to the historic significance of the road as a whole, and burial of the features will not alter the characteristics that qualify the property for inclusion on the National Register of Historic Places (NRHP).

Regarding indirect effects, none of the historic properties are considered significant for architectural, engineering, or other visual characteristics. Furthermore, the proposed mitigation is designed to restore the Sonoita Creek floodplain to its historical flow regime, which is expected to result in the gradual return of large portions of the APE to a riparian environment similar to that which would have characterized this area throughout most of prehistoric and historic times. Therefore, the Corps determined that there will be no indirect adverse effect to the historic properties in the APE.

The SHPO concurred with the Corps’ determination of no adverse effect to historic properties from the proposed compensatory mitigation activities on September 1, 2017.

Following the 2017 inventory and consultation, the locations of two proposed fence lines were finalized in accordance with the Biological Opinion from the U.S. Fish and Wildlife Service. These are a wildlife-exclusion fence separating the restored floodplain habitat from State Route 82 to the west and a wildlife-friendly fence along the eastern side of the parcels designed to permit wildlife to enter the restored area while excluding livestock. The final plans for the two fence lines revealed that not all of the proposed areas of new fence construction were surveyed in 2017.

As a result of the additional survey required for the fence lines, the APE was increased by a total of 65.59 acres consisting of four non-contiguous corridors of varying widths comprised of both private (55.06 acres) and Arizona Department of Transportation- (ADOT-) owned land (10.53 acres). These corridors measure between 845 and 2,758 meters long and are located along and east of State Route 82 between Sonoita and Patagonia, Santa Cruz County, Arizona. Three previously recorded linear sites were identified: the former grade of the New Mexico & Arizona Railroad, an in-use natural gas pipeline exempt from Section 106 review by federal agencies, and the abandoned alignment of State Road (SR) 82. The three sites are all associated with Euro-American land use for transportation infrastructure and utilities during the Late Historic period. The former grade of the New Mexico & Arizona Railroad and abandoned alignment of SR 82 have been determined eligible for inclusion in the NRHP.

All new fence line construction has been designed to avoid the historic properties. The wildlife-friendly fence crosses the southern end of the New Mexico & Arizona Railroad extension that was recorded in 2018. At this location, the fence is already in existence, and the only project activity would be the replacement of the upper and lower barbed wire strands with smooth wire strands. All fence replacement would be carried out by hand, and no vehicles would be driven across the railroad grade. It is further noted that these fences, by their nature, allow light to pass, and will not impede the visibility of any of the NRHP-eligible sites. The Corps has therefore determined that the fence lines will not cause indirect adverse effects to the historic properties in the APE. The SHPO concurred with the Corps’ determination of no adverse effect to historic properties from the proposed compensatory mitigation activities on October 23, 2018.

On October 24, 2018, the Corps received notice from the Tohono O’odham Nation’s (“Nation”) Tribal Historic Preservation Officer that the Nation does not concur with the determination of no adverse effect to historic properties, stating that a cultural landscape study is necessary to further evaluate the impacts from the proposed scope of work. In response to subsequent communications attempting to resolve the dispute, a second correspondence from the Nation dated November 9, 2018 indicated that the THPO’s view is that there would be an adverse effect on the cultural and natural landscape of the Sonoita Creek project area. In response to these notifications the Corps is requesting an opinion from the Council regarding our determination of no adverse effect to historic properties from the proposed  compensatory mitigation at Sonoita Creek Ranch.

ATTACHMENTS: A copy of the letter the Corps sent to the Council (Letter to ACHP 1.1 MB) requesting an opinion regarding the determination of no adverse effect to historic properties from the proposed activities at the Sonoita Creek Ranch Compensatory Mitigation Site is attached to this notice. A package of consulting party correspondence concerning the determination of effect can be accessed at Correspondence, 6.9 MB. The Habitat Mitigation and Monitoring Plan (HMMP) can be accessed at HMMP 165 MB (very large file).

To request additional information regarding this Public Notice, please contact:

Chris Parrish

US Army Corps of Engineers, Albuquerque District

4101 Jefferson Plaza NE Albuquerque, NM 87109

505-231-3586

E-mail: christopher.m.parrish@usace.army.mil