Iron King Mine And Humboldt Smelter

Description and History

The Site is a combination of sources and releases from two areas: the Iron King Mine and the Humboldt Smelter. A portion of the Town of Dewey-Humboldt is situated between the mine and the smelter. Three waterways (Chaparral Gulch, Galena Gulch, and Agua Fria River) also transect the Site.

The Iron King Mine area covers approximately 153 acres. The majority of this area is covered by tailings and waste rock piles. There are five retention ponds, at least five mine shafts, a collapsed mine shaft (glory hole), and areas of stained soil. The Iron King Mine was an active mine from 1904 until 1969. The mine was expanded in 1936 to remove lead, gold, silver, zinc, and copper from underground. A 140-ton mill was erected to crush ore and was expanded to 225-ton capacity in 1938. A cyanide processing plant was added to the site in 1940 to treat the mill tailings to enhance precious metal recovery. Waste rock and tailings were deposited in large piles adjacent to actual mine property boundaries. More recently, the mine tailings from the site have been used to create fertilizer.

The Humboldt Smelter occupies approximately 182 acres. This area is covered in approximately 763,800 square feet of yellow-orange tailings, over 1 million square feet of grey smelter ash, and 456,000 square feet of slag. The Humboldt Smelter operated from the late 1800s until the early 1960s. The original smelter burned down in 1904 and a smelter that processed 1,000-tons of ore per day was rebuilt in 1906. This smelter operated until 1918 and then intermittently between 1922 and 1927. The smelter reopened in 1930.

Contaminants and Risks

The contaminants of concern at this site are arsenic, lead, and sulfate. The primary sources of contamination are:

• Iron King Mine Main Tailings Pile and Impoundment/Ponds
• Iron King Mine Small Tailings Pile
• Humboldt Smelter Ash Pile
• Humboldt Smelter Impoundment/Pond
• Humboldt Smelter Tailings Pile
• Lower Chaparral Gulch

The locations of these source areas are shown on the map titled "Site Features" below. These sources contain average arsenic and lead levels from one to two orders of magnitude greater than average background arsenic and lead levels. Exposure to these metals could present a health risk if a person is in contact with them over a long period of time. EPA recommends that residents, especially children and the elderly, limit or avoid contact with soils and any water in these areas, and obey EPA caution signs until these areas can be addressed through cleanup actions. Residents should limit or avoid spending time in Chaparral Gulch as tailings have been deposited along most of its length.

Human Health and Ecological Risk Assessments
EPA conducted a human health risk assessment to evaluate the potential harm to residents posed by site contaminants. The risk assessment indicates that contamination at the site could pose health risks (cancer risks and noncancer hazards) if no cleanup action is taken.

EPA conducted an ecological risk assessment to evaluate whether potential exposure to contaminants could harm plants or animals. The assessment found that contamination poses risks to many plant and animal groups (for example: mammals, birds, reptiles, and aquatic organisms).

The results of the RI indicate a need to take cleanup actions to protect human health and the environment. The next phase in the Superfund process is the Feasibility Study, which focuses on developing cleanup options that will reduce the health risks posed by the site to people, animals, and plants.

Who is Involved

Cleanup Results to Date

Potentially Responsible Parties

Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.

The term "Potentially Responsible Parties" or "PRPs" refers to companies or individuals who are potentially responsible for generating, transporting, or disposing hazardous substances associated with the site. PRPs also include current owners and operators of the site and parties who were owners or operators during a time of disposal.

As part of the Superfund process, EPA identifies those parties that are "potentially responsible parties" who fall into one or more of the above categories of PRPs, and then may negotiate with the PRPs to perform cleanup activities under EPA oversight and/or help pay EPA's response costs. EPA has conducted a search for parties associated with the Iron King Mine-Humboldt Smelter Superfund Site and on November 19, 2009, issued a General Notice Letter to 14 parties advising them of their status as PRPs under CERCLA.

Community Involvement

Public Meetings: The EPA recognizes that Americans have the right to be involved in the government decisions that affect
their lives. EPA’s experience has been that when the public is involved in EPA’s work, the cleanup process results in a better outcome and a more robust remedy.

At the Iron King Mine – Humboldt Smelter Superfund Site, EPA’s Community Involvement Program helps citizens participate throughout the cleanup process, including the investigation phase and the remedy selection phase. The goals of EPA’s Community Involvement Program are to:
1. Provide opportunities for the public to become actively involved
2. Meet the community’s information needs
3. Incorporate issues and concerns into cleanup decisions
4. Give feedback to the public on how their issues and concerns were incorporated into the cleanup work

EPA and ADEQ have a number of ways for the community to become more knowledgeable about and involved with the Iron King Mine – Humboldt Smelter Superfund Site.

Community Involvement Plan
The Iron King Mine – Humboldt Smelter Superfund Site Community Involvement Plan provides a detailed explanation of how EPA and ADEQ will encourage public participation in the cleanup decision-making process. It is a flexible plan that organizes both EPA’s and ADEQ’s efforts but can change
based on new community needs. A copy is located at the Dewey-Humboldt Town Library and is also available below.

Community Advisory Group
A Community Advisory Group is stakeholder forum where individuals or those representing groups meet together to learn more about the Superfund cleanup process, and to provide information, issues and
concerns to EPA and ADEQ. Membership in the group does not require a technical background.

The CAG is a self-forming and voluntary group. Although EPA and ADEQ do not manage the group, EPA can provide limited support, such as making copies, providing documents, rental meeting rooms, paying for meeting notices, etc. The biggest advantage of a CAG is that it meets regularly and at intervals that are usually far more frequent than EPA’s event-driven meetings. In this way, attendees can get the
latest information and can talk directly to EPA and ADEQ representatives.

If you are interested in participating in a CAG, please send an email with your contact information to dhsmelter@gmail.com (Note: This e-mail address is managed independently by a Dewey-Humboldt resident and is not associated with EPA).

Technical Assistance Grant Available
EPA offers a Technical Assistance Grant (TAG) to a community affected by a Superfund site by providing money for activities to help the community participate in decision making. An initial grant up to $50,000 is available to a qualified community group so they can contract with an independent
technical advisor to interpret and help the community understand technical information about their site.
After the independent technical advisor reviews the site related documents, the advisor can help the community formulate its issues and concerns, and communicate them effectively to EPA.

To qualify, the TAG recipient must be or become an incorporated non-profit organization. EPA can pay for the costs of incorporation. The group must establish a bank account to receive the funds and create a record of how they spent the funds. EPA staff are available to help a group through the application process. Interested community members may contact David Cooper (contact information below).

Mailing Lists
If you would like to be added to the site mailing list, please contact David Cooper (contact information below) or call the toll free hot-line (800) 231-3075 and leave a message with your name and address. EPA also sends periodic updates to the site email list. If you would like to be added to the email list, please contact Monika O'Sullivan (contact information below).

Additional Links

ADEQ website: http://www.azdeq.gov/environ/waste/sps/statesites.html#ironking