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Mammoth Stamp Mill Site Closed
The Inyo National Forest has closed the Mammoth Stamp Mill Site due to elevated levels of metals that were determined to pose a risk to human health and the environment. Antimony, arsenic, lead and mercury were identified as the primary chemicals of concern.
Records can be viewed at:
Inyo National Forest
Supervisor's Office
351 Pacu Lane
Bishop CA 93514
Contact: Colleen Garcia
Document Links
Technical Memo: Data Gaps Sampling Investigation - June 6, 2022
Forest Closure Order: Mammoth Mill, 5/16/2022 - Expires 5/15/2024 (Previous Forest Order expired 5/16/2022)
Mammoth East Area Site Investigation, 07/2021
Work Plan for Data Gap Sampling Mammoth Stamp Mill Site 11/2020
Supplemental Characterization Report for the Cabins Area at Mammoth Mill 12/2019
Map: Figure 11. Extent of Metals-Impacted Soil in Cabins Area
Map: Figure 2. Cabin Area Definition
Mill City Tract Public Meeting Minutes, 11/16/2019
Mammoth Mill Site Update : Public Meeting 11/16/2019
Focused Site Inspection (Focused SI) for the Cabins Area Mammoth Mill Site 01/12/2018
Unilateral Administrative Order (UAO) for Time Critical Removal Action 11/03/2017 PDF (3MB)
News Release 5/1/2017
Signed Time Critical Removal Action Memo 4/14/2017 PDF (2 MB)
Mammoth Mill Fact Sheet 04/05/2017
Frequently Asked Questions for Mammoth Stamp Mill CERCLA Site 04/05/2017
Technical Memorandum for Refinement of Streamlined Human Health Risk Assesment. 1/23/2017
Preliminary Assessment/ Site Inspection (PA/SI) 11/2016 PDF (46 MB)