About the Project
Pinto Valley Mine is an existing copper and molybdenum mine located approximately 8 miles west of Town of Miami, Arizona, on private and National Forest System (NFS) lands in the Globe Ranger District, Tonto National Forest, in Gila County. Pinto Valley Mine has operated continuously from 1974 with the exception of a short period of curtailed operations in 1983, as well as curtailments from 1998 to 2007 and from 2008 to 2012. The mine has operated continuously since the 2012 re-start. Pinto Valley Mining Corp (PVMC) acquired the Pinto Valley Mine in 2013. In May 2016, PVMC submitted a proposed Mining Plan of Operations (MPO) to the Tonto National Forest for further expansion of the existing copper and molybdenum mine on lands in the Tonto National Forest. PVMC submitted minor revisions to the May 2016 MPO to the Forest Service in September 2016. The Tonto National Forest determined the MPO to be complete in September 2016.
Tonto National Forest is evaluating the proposed action to comply with statutory and regulatory obligations to respond to a proposed MPO submitted by PVMC. The Forest Service's purpose and need for this project is to consider approval of the proposed MPO submitted by PVMC, which would govern surface disturbance on NFS lands from expansion of existing mining operations, extension of the mine life to 2039, and would consolidate prior authorizations that are reasonably incident to extraction, transportation, and processing of copper and molybdenum.
Proposed Action and Purpose and Need
The proposed action is the MPO as submitted by PVMC and summarized below. Pinto Valley Mine expansion would affect federal lands administered by Tonto National Forest and private lands owned by PVMC. The Forest Service's purpose is to analyze the proposed action as required by regulations at 36 CFR 228.5(a). Approval of the proposed MPO would be a major federal action subject to National Environmental Policy Act of 1969. Under the regulations, the Forest Service must: (1) evaluate the proposed MPO; (2) consider Requirements for Environmental Protection set forth at 36 CFR 228.8, including to minimize adverse effects where feasible, comply with applicable laws, regulations, and standards for environmental protection, and provide for reclamation; and (3) respond to the proposal as set forth at 36 CFR 228.5(a). The Forest Service would only approve mining operations on NFS lands associated with the Proposed Action, since the Forest Service does not have jurisdiction to regulate mining operations that occur on private land.
Existing and Proposed Mining Operations
Pinto Valley Mine is an existing open pit copper and molybdenum mine with adjacent milling and processing operations, tailings disposal areas, and waste rock disposal, all operated by PVMC. The MPO describes mining operations conducted by PVMC on NFS lands surrounding PVMC property. The NFS lands are administrated by the U.S. Department of Agriculture, Forest Service as the Tonto National Forest (TNF).
The majority of Pinto Valley Mine is located on PVMC property. However, certain facilities and operations are located on TNF, and were authorized by the Forest Service or the U.S. Department of Interior, Bureau of Land Management (BLM) through Rights-of-Way, Plans of Operations, Special Use Permits, and a Letter Agreement. The BLM Rights-of-Way were transferred to the Forest Service in 1989. The authorizations date from as early as the 1940s, and have been amended, updated, and re-authorized over the years. Some facilities were inadvertently placed or expanded onto NFS lands without modification to existing authorizations by PVMC's predecessors.
The Forest Service had previously requested that all of the prior authorizations for the Pinto Valley Mine be consolidated into a single Plan of Operations to replace prior permits and approvals, and to address inadvertent encroachments on to NFS lands. Since acquisition of Pinto Valley Mine in 2013, PVMC has planned further facility development, including additional activities on NFS lands. PVMC submitted the final MPO to the Forest Service in May 2016. The activities described in the MPO are anticipated to last through 2039. Reclamation activities would extend 5 to 10 years beyond 2039, and some facilities for access and environmental monitoring would remain on NFS lands indefinitely.
Existing surface disturbance associated with the Pinto Valley Mine currently encompasses an estimated 3,845 acres, of which 3,389 acres are on private and 456 acres are on NFS lands. The proposed disturbance acreage would be an additional 1,011 acres of surface disturbance (766 acres on private land, 245 acres on NFS lands) for a total estimated surface disturbance of 4,855 acres (4,155 on private land, 701 acres on NFS lands).
Each of the past, present, and proposed future uses of NFS lands is addressed in the MPO. Existing or proposed mining use of NFS lands includes portions of the Open Pit (proposed 28.9 acres) and 19 Dump (75.8 acres). The Open Pit does not currently extend onto NFS lands, but is proposed to do so beginning in 2020 to access the portion of ore body that extends outside PVMC property. The 19 Dump was constructed on NFS lands between 1984 and 1993, and would not be further expanded.
Existing or proposed milling, processing, and disposal use of NFS lands includes portions of three tailings storage facilities: Cottonwood Tailings Impoundment (278.5 acres), Tailings Storage Facility No. 3 (25.8 acres), and Tailings Storage Facility No. 4 (proposed 171 acres). Cottonwood Tailings Impoundment was constructed between 1944 and 1984, and would not be further expanded. Tailings Storage Facility No. 3 was constructed in 1974, and extended onto NFS lands in 1994. This facility is used intermittently for tailings storage. The current mine plan proposes raising the top elevation of tailings to 3,860 feet above mean sea level (amsl). Tailings Storage Facility No. 4 does not currently extend onto NFS lands; the MPO proposal is to raise top elevation to a maximum elevation of 4,250 feet amsl, extending the facility onto NFS lands.
Existing and proposed transportation use of NFS lands includes Forest Roads (23.76 miles) and temporary access roads (15.49 miles). PVMC and predecessors have used Forest Roads to access nearby mine structures or facilities. PVMC would continue to use Forest Roads to access mine facilities. Temporary access roads were constructed by PVMC's predecessors to directly access mine facilities (earthwork structures, infrastructure, and environmental controls) for maintenance and monitoring. Most temporary access roads extend from Forest Roads to access nearby facilities. Two new temporary access roads are proposed around the Open Pit and Tailings Storage Facility No. 4, while other roads would be subsumed by expanded facilities.
Existing utility use of NFS lands includes electrical powerlines (10.9 miles) and water pipelines (17.9 miles) that generally follow Forest Road or temporary access road alignments. Electrical powerlines provide power to various mine facilities. Approximately 0.8 miles of existing electrical infrastructure would be subsumed by the proposed development of the Open Pit and Tailings Storage Facility No. 4. The only power line PVMC proposes to add on NFS lands is for continued operation of Tailings Storage Facility No. 4 as the facility extends onto NFS lands, for a proposed 0.8 miles. Water pipelines deliver water to various mine facilities. Two unused water pipelines, totaling 1.5 miles in length, are proposed to be removed. Two other pipelines, totaling 1.9 miles are proposed to be installed. The powerlines and pipelines would continue to be used and maintained.
Existing water supply and stormwater management facilities on NFS lands include one well (0.02 acre), several ponds and reservoirs (38.62 acres), and two water storage tanks (0.2 acre), most of which are connected by the water pipelines described above. These uses of NFS lands would not change.
Existing support facility use of NFS lands consists of a sign identifying the site (0.01 acre). This use would not change.
In summary, at the end of the current planned life of the mine, PVMC would use approximately 649 acres of NFS lands and 26.96 miles of Forest Roads to access mine facilities and/or as alignments for linear utility infrastructure.
The Forest Service role is focused on environmental review and preparation of an EIS for the proposed mine expansion related to activities that would occur on National Forest System lands, in accordance with the National Environmental Policy Act. The EIS will consider and disclose environmental effects that could result from the proposed action and other alternatives included in the EIS. Connected actions related to the MPO and potential amendment of the Tonto National Forest Plan, if required, would be analyzed in the EIS. Impacts from past, present, and reasonably foreseeable future actions will be considered in combination with impacts of the proposed project to estimate potential cumulative impacts.
Tonto National Forest will play a key role in the project including:
- Analyzing and disclosing environmental effects of the mine expansion on National Forest System land and connected actions on private land
- Conducting government-to-government consultations with potentially affected Native American tribes
- Developing mitigations to protect surface resources of Tonto National Forest
- Administering approved mining plans of operations that authorize mining-related disturbance on national forest lands
- Administering financial assurance to ensure that portions of the mine facilities constructed on National Forest System lands are reclaimed.
Other regulatory agencies will have important roles in permitting, approval and regulation of the mine including Arizona Department of Environmental Quality, Arizona Department of Water Resources, Arizona Game and Fish, Arizona State Mine Inspector, US Environmental Protection Agency, US Fish and Wildlife Service, the State Historic Preservation Office, US Army Corps of Engineers, and the federal Mine Safety and Health Administration.