The work completed the second part of a two-phase project designed to render the former Newmire Vanadium Mill site suitable for recreational use. The site is not suitable for commercial or residential use.
The cleanup saw nearly 36,000 tons of historic mining material and impacted soil removed from the site, and some 18,700 cubic yards of clean backfill applied to the area. Original projections estimated the removal of 19,000 tons of contaminated soil and materials from the area.
“On the north side we ended up removing well over our projected estimate,” Barbara Nielsen, remediation projects manager for Freeport-McMoRan, Inc., told the commissioners.
“We ran into much more tailings type material and debris than we originally thought would be there.”
The Newmire site consisted of a mill area that processed vanadium ore from nearby mines from 1908 into the 1920s, a tailings disposal, and other facilities to occupy about 15 acres of property on either side of the highway.
Although the site was demolished in the early 1950s, it was not until decades later that Cyprus Amax Minerals Co., a Freeport-McMoRan subsidiary, undertook the mill site cleanup under the Colorado Department of Public Health and Environment’s Voluntary Cleanup and Redevelopment Program as a condition of that company’s 1998 sale of the site to the German chemical company Chemetall GmbH.
The program encourages the voluntary cleanup of contaminated sites by removing barriers such as fear of prosecution that may be held by landowners, according to the CDPHE website.
In May 2006, Chemetall Foote (the current landowner sold by Chemetall GmbH to Rockwood Specialties Group Inc. in 2005), formally authorized Cyprus Amax to remediate the low-level radioactive waste site. The science and engineering consultancy firm Environmental Management Consultants Corp. – or EMC2 – was hired for the job.
The first phase of the project, remediation of the south side of the highway, took place between June and October 2009. At that time workers hauled away some 12,000 tons of historic mining material and impacted soil from below the highway and applied some 7,400 cubic yards of clean backfill to the area. Another 2,200 tons of contaminated materials were removed from the north side of the highway at that time.
Monitoring for radioactivity established during the first phase of the project was repeated during the second phase and revealed satisfactory results.
While in 2009 workers were exposed an average of 28 millirems of radioactivity per year (and a maximum exposure of 61 millirems per year) out of an allowable exposure of 5,000 millirems per year, in 2010 the average exposure decreased to 23 millirems of radioactivity per year with a maximum exposure of 51 millirems per year.
Perimeter pumps located upwind and downwind of the site that checked for escaping radioactivity revealed mixed results in 2010 compared to the previous year. While levels during both years remained much lower than allowed by regulatory limits, upwind exposure to radionuclides in 2010 was slightly lower than in 2009, while downwind exposure was slightly higher.
Still, “You can see we’re a couple orders of magnitude less than the requirement,” said Nielsen.
Results for personal monitoring of metals including lead, arsenic and vanadium all returned below regulatory requirements in both 2009 and 2010.
Acute exposure to vanadium can cause nose and throat irritation including coughing, wheezing and shortness of breath. With chronic exposure it can lead to chronic bronchitis and allergic dermatitis.
However, vanadium occurs in the same ores as uranium, which was also present in the Newmire tailings.
Uranium decays into radium, which itself decays into radon gas.
Radium and radon both emit radioactive alpha particles that are easily stopped with materials as thin as a piece of paper. For that reason, external exposure to alpha radiation is not of great concern.
However, alpha particles can attach to particles of dust and cause serious health threats if inhaled or ingested by exposing living tissue to radiation and increasing the risk for cancer, making dust suppression the best way to control radiation associated with the site.
While all but two samples tested for dust and silica met regulatory standards in 2009 (both taken from one operator who was found to have been working with his bulldozer cab door open), all samples for dust and silica complied with Occupational Safety and Health Administration guidelines in 2010.
“We did have an accelerated and more disciplined, more frequent dust suppression program in 2010,” noted EMC2 project manager Moe Pasha.
Except for, perhaps, the revegetation of the south side of Highway 145 last year that was not done in accordance with the work plan – but seems to be re-establishing itself nonetheless – the county is generally pleased with the work.
“It looks like it’s coming in,” County Environmental Health Director Dave Schneck said of the restored riparian habitat. “It’s a matter of seeing how well it gets established.”
In order to meet state guidelines, the treatment area must fill in with at least 70 percent of the vegetation cover found in adjacent, undisturbed areas.
“In general I’m happy to see that the project was completed and the contaminated soils removed,” Schneck continued, explaining that the materials could not remain in place because of the danger they would be carried into the San Miguel River by flash flood or debris flow.
Instead they were trucked to the Clean Harbors Deer Trail facility in northeastern Colorado.
“I’m really happy that they did the project, they got the stuff out of there and they didn’t destroy the river corridor in the process; they worked with us to come up with a more gentle and less impactful treatment,” Schneck said. “In my view it’s a big improvement.”
But because of its steeper grade and drier terrain, the north side of the highway could prove more challenging to revegetate to the 70 percent guideline.
Nevertheless, Schneck remained confident that the company would remain committed to working on the vegetation until it meets the standards.
County Commissioner Art Goodtimes also praised the work.
“I think you guys should go for an award or something cause we’d be happy to support you and that’s not always the case with counties, especially a county as difficult as us,” he said.
With construction complete, the company will file a final report with the CDPHE. Once it is reviewed and approved, a No Further Action and Site Acceptance letter will be issued by the agency, according to the project website at http://newmiresite.com.