United States Department of the Interior
OFFICE OF THE SECRETARY
IN REPLY REFER TO:
30 January 2012
Mr. Jim Upchurch
Subject: Draft EIS, US Forest Service, Rosemont Copper Project, Proposed Construction, Operation with Concurrent Reclamation and Closure of an Open-Pit Copper Mine, Coronado National Forest, Pima County, AZ
Dear Mr. Upchurch:
The Department of the Interior has received and reviewed the subject document and would like to submit the following additional comments :
Onyx Cave, located in Santa Cruz County, Arizona, is approximately 8 miles south of the Rosemont Copper Mine project area. Onyx Cave was designated by the Secretary of the Interior as a National Natural Landmark (NNL) in 1974. As such, it has been recognized as a nationally significant resource.
The cave consists of extensive cave passages and outstanding and beautifully developed speleothems, including numerous shields. Such features are developed in few caves as extensively and distinctively as here. Shields at this site are several feet across and variously ornamented with secondary stalactites or draperies. Other decorative formations include large, abundant helictites, rim stone with pimpled undersurface, flowstone of various shades, segmented pillars with discs of rim stone and some remarkably long and slender soda straws.
Established in 1962, the NNL Program is managed by the National Park Service (NPS). Sites are designated natural landmarks based primarily on their illustrative character and present condition, and collectively represent the best examples of the nation's diverse natural features.
Onyx Cave is noted in the DEIS in the “Other Geological Resources” section of Chapter 3 “Affected Environment and Environmental Consequences,” however, it receives only brief mention in general, with no specific discussion regarding its NNL designation.
While NNL designation does not mandate specific land management or impose any new land use restrictions, as specified in Section 62.6(f) of the NNL Program Regulations, “Federal agencies should consider the existence and location of designated national natural landmarks, and of areas found to meet the criteria for national significance, in assessing the effects of their activities on the environment under section 102(2)(c) of the National Environmental Policy Act (42 U.S.C. 4321).” Thus one of the goals of the NNL Program is to equip land managers with information regarding designated sites such that land-use planning decisions can be made that eliminate or minimize impact to these significant features.
Onyx Cave is considered a “wet” cave and thus the significant cave formations described above continue to form and grow. The pit associated with the proposed Rosemont Copper Mine would intercept groundwater in the immediate vicinity of the mine, resulting in drawdown in the regional aquifer.
Given this, the NPS wants to ensure that adequate consideration is given to the potential impacts of the proposed project on the significant cave features highlighted by the Onyx Cave National Natural Landmark designation. If the hydrology of the Onyx Cave system was changed as a result of the Rosemont Copper Mine Project, it may compromise the conditions necessary to sustain the growth and development of the nationally recognized features at this site.
For questions, please contact, Heather Germaine, Regional NNL Coordinator at email@example.com or 303-969-2945.
We appreciate this opportunity to provide comments on the Rosemont Copper Project, and we look forward to continuing our work with the USFS in developing the DEIS.
Patricia Sanderson Port