This Site/Facility of Interest is an online resource that provides interested parties easy access to information about the Minerals Research, Inc. (MRI) facility.

Air Quality Permitting

On Oct. 31, 2023, ADEQ received an Individual (Class II) Air Quality Permit Application from MRI for the operation of its Cottonwood facility and deemed the application complete on Nov. 14, 2023 (see following Background and Documents for details).

ADEQ is reviewing MRI’s application and expects to make proposed air quality permit documents available to the public for review and comment during the first half of 2025. ADEQ’s air quality permitting process for an Individual Air Quality Permit involves a comprehensive review of emissions calculations and associated air dispersion modeling and the development of a draft permit and technical supporting document. ADEQ will make these permitting documents available for public comment, and conduct both an informal community meeting and a formal public hearing for the draft air quality permit prior to making a final permit decision.

• Air Quality Permit Application | View >

Other ADEQ Activities

ADEQ Ambient Air Quality Monitoring

At a community meeting ADEQ conducted on Dec. 13, 2023, in partnership with the City of Cottonwood, ADEQ committed to conduct ambient air quality monitoring for particulate matter and heavy metals in the vicinity of MRI’s facility. ADEQ set up ambient air quality monitoring equipment at the two locations discussed at the community meeting — the Cottonwood Kid’s Park and the Veterans of Foreign Wars (VFW) site. Ambient air quality monitoring commenced on Feb. 15, 2024 and ended on June 9, 2024.

• Cottonwood Air Quality Monitoring Report 2024 | View >

Based on the particulate matter analysis, which indicated elevated levels of lead at the VFW site, ADEQ is conducting at least three additional months of lead sampling beginning in December 2024. This would not be possible without the continued support and involvement of volunteers from ADEQ’s AZ Community Science Alliance. ADEQ extends its sincere gratitude to these dedicated volunteers whose assistance is invaluable to this monitoring effort. Following the completion of lead sampling, another Air Quality Monitoring Report will be published. 

ADEQ Preliminary Investigation (PI)

ADEQ conducted a PI under our state Water Quality Assurance Revolving Fund (WQARF) program | Learn More >

The PI focused on potential impacts to soil and groundwater associated with the slag pile located at the MRI facility and the former smelter operations in the surrounding area. In addition to reviewing available historical reports and environmental data regarding operations and activities in the area of the MRI facility, the PI includes collecting soil and groundwater samples in the field for laboratory testing. During March and April 2024, ADEQ collected and tested soil and groundwater samples from properties and wells that allowed ADEQ access to conduct sampling. 

• PI Report for the 6th Street and Birch Street Site | View >

Based on the PI test results, ADEQ determined that additional soil sample collection and laboratory testing is needed to determine natural background metals concentrations and what actions may be needed. ADEQ has identified ten focus areas in the Site area to conduct this additional work, which will include aluminum testing. Following the completion of the additional soil sample collection, and laboratory testing, ADEQ will review and analyze the data and publish an amended PI Report that includes ADEQ’s conclusions and next steps.

ADEQ is continuing to share its data with the Arizona Department of Health Services for its health consultation work.