The Colorado Department of Public Health and Environment (CDPHE) and the Environmental Protection Agency (EPA) held a third meeting on August 28, 2024, on the status of cleaning up the Central City-Clear Creek Superfund site. The public meeting was held at the Idaho Springs City Hall.
The current cleanup effort is still in an evaluation phase, called a Feasibility Study, which is determining which properties have a health risk and how they should be cleaned up.
CDPHE Communication Specialist Branden Ingersoll acted as the moderator for the meeting, which included representatives and presentations from both CDPHE and the EPA.
The meeting featured a history of the site and a review of the Superfund process. After the presentations, the public’s questions were taken for over an hour.
Ingersoll started the presentations by talking about the Colorado Mineral Belt, which is a highly mineralized geological area that spans Boulder to Durango, and the impact of precious metals mining on the environment during the 1800s.
In order to extract those precious metals, Ingersoll noted, mining for ore produces two kinds of waste. There is waste rock, which is excess material that comes from excavating the tunnels. It can contain significant levels of heavy metals like lead, arsenic, and cadmium.
The second kind of waste is called mill tailings, the byproduct of the extraction of precious metals. The ore was ground into a powder and then leaching techniques were used to separate the precious metals. The discarded tailings can also contain significant levels of lead, arsenic, and cadmium.
Both waste rock and mill tailings were left in piles around the mines and mills, containing potentially hazardous waste. Ingersoll cautioned people from playing or driving ATVs on these piles, since that activity can stir up the heavy metals, which can then be inhaled by any living creature.
The current cleanup effort, called Operable Unit 5 (OU5), is focused on cleaning up waste piles on private property in order to protect the health of those living nearby. Previous cleanup efforts (OU1 through OU4) concentrated on building water treatment plants, removing or capping waste piles on public property, and testing domestic wells.
In detailing the process for completing an Operable Unit, Ingersoll highlighted the Feasibility Study step. This is where the agencies assess what practical scientific solutions are available, how much they will cost, and how long they will take. The agencies are hoping to complete this step this fall so they can produce a Proposed Plan and Record of Decision which will lead by next summer to contracts and implementation of the remedial plan.
A lengthy question-and-answer segment followed Ingersoll’s presentation. Both in-person and online participants were primarily concerned with immediate health risks and property valuations of the affected properties. The agencies said that they will have some real estate experts at future meetings to answer property valuation questions.
One intriguing question concerned letting private contractors reprocess the piles using modern techniques in order to further extract any remaining precious metals, which would offset the costs of remediation.
A recording of the meeting with its PowerPoint slides can be found at the CDPHE website (cdphe.colorado.gov/ hm/central-city-clear-creek). It is the August 28, 2024, meeting recording under Presentations.
The next OU5 Superfund meeting will be held on October 3, 2024, at the Old Gilpin County Courthouse in Central City.
For more information about the Central City-Clear Creek Superfund OU5 project, contact Banden Ingersoll (720-810-7912 or Branden. Ingersoll@state.co.us), or Angela Zachman (720-614-4842). Gilpin County Public Health Director Alisa Witt (303-582-5803 or awitt@gilpincounty.org) can also answer questions about lead and other heavy metal contamination.
