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WQD | Permit of Interest - Hermosa Project, South32 Hermosa Inc.

Water Quality Permit of Interest

Hermosa Project — South32 Hermosa Inc.

Revised on: Aug. 23, 2024 -  8:06 a.m.

This permit of interest online resource provides interested parties easy access to information about the Hermosa Project, owned by South32 Hermosa Inc., formerly Arizona Minerals Inc. (AMI).

Facility Information

The Hermosa Project, owned and operated by South32 Hermosa Inc., is located approximately five miles south of the Town of Patagonia, Arizona in Santa Cruz County. 

Location

749 Harshaw Road, Patagonia, Arizona 85624

Recent Permitting Activity 

Clean Water Act

On July 3, 2024, ADEQ issued a renewal Clean Water Act individual permit to South32 Hermosa Inc.:

South32 Hermosa Inc. also has coverage under the Mining Multi-Sector General Permit (MSGP) for industrial stormwater discharges. 

  • Notice of Intent (NOI) Certificate | View >
  • Mining Multi-Sector General Permit (MSGP) | Learn More >

South32 Hermosa Inc. also has coverage under the De Minimis General Permit (DMGP) for water well development and maintenance. 

  • Notice of Intent (NOI) Certificate | View >
  • De Minimis General Permit (DMGP) | Learn More >
Aquifer Protection Program Permitting Significant Amendment

In December 2023, ADEQ received an Individual APP permit application (significant amendment) from South32 seeking to amend the APP Permit No. P-512235 

  • Application significant amendment to APP (2024) | View >
  • ADEQ’s Comprehensive Request for Additional Information| View >
  • South32 Hermosa Inc. Response Letter | View >

Public Notice

The comment period has been extended for the preliminary decision to issue the APP permit significant amendment to South32 Hermosa, Inc., for its Hermosa Project. The comment period ends on Oct. 18, 2024 | View Public Notice >

ADEQ held an in-person public hearing for the APP permit significant amendment on Oct. 2, 2024, 6 – 8 p.m.

Facility Reports

Clean Water Act

The individual permit requires regular monitoring of the treated discharge. The monitoring frequencies are specified in the permit and vary from monthly to annually, depending on the parameter. South32 must send these monitoring results to the ADEQ each month through Discharge Monitoring Reports (DMR). 

ADEQ uses these monitoring results to check if South32 is following the effluent limits set in the permit. ADEQ can change the permit if the DMR data shows there is effluent toxicity, a need for more permit limits, or if the levels in the permit are exceeded.

You can view and download the DMR data for South32 from the U.S. Environmental Protection Agency’s (EPA) Compliance and Enforcement Online (ECHO) website by entering the AZPDES Permit Number (AZ0026387) at the following link:

Facility Archives

Individual AZPDES Permit — LTF 66046 (2018)

Individual AZPDES Permit Modification — LTF 85604 (2021)

  • Permit (AZ0026387) | View >
  • Statement of Basis | View >
  • Response to Comments | View >

Mining MSGP - LTF 67872 (2016)

  • Notice of Intent (NOI) Certificate | View >

Individual APP Permit — LTF 65051 (2017)  

Individual APP Permit — LTF 71251 (2019) 

Individual APP Permit - LTF 75937(2020) 

Individual APP Permit — LTF 83040 (2020) 

Individual APP Permit — LTF 98095 (2023) 

Determination of Applicability (DOA)

  • Request from applicant (2022) | View > 
  • ADEQ Response (2022) | View >
  • Request from applicant (2023) | View >
  • Supplemental Information — Hermosa Project Cemented Paste Tailings Backfill | View >
  • ADEQ Response (2023) | View >

Environmental Impact Statement (EIS)

Environmental Inspections and Enforcement

  • Surface Water Protection (SWP) — Inspection Report (2023) | View >
  • SWP Stormwater Inspection Report (2022) | View >
  • SWP Stormwater Inspection Report (2019) | View >
  • Notice of Violation (2019) | View >
  • Water Quality Follow-Up Inspection Report (2018) | View >
  • Notice of Violation (2018) | View >
  • ADEQ APP Permit Field Inspection Report (2024) | View >

Looking for air quality permits related to this facility? 

The Hermosa Project also has air quality permits issued by ADEQ | View >

Groundwater APP Permits
Email >

Arizona Department of Water Resources (groundwater quantity) | View >

Wildlife including Migratory or Local Bird Species | View >