Clean-up of Lincoln Park, Colorado

Introduction

The Source of the problem

The area effected

Clean-up of Lincoln Park, Colorado

• 1958 – the Cotter Corporation began milling uranium ore outside Canon city, Colorado.

• Canon mill has a nominal capacity of 1,200 tons per day;– Is operated with acid or alkaline leach circuit.

• The mill operations produced unwanted metals and radioactive particles.

• Before 1980 these waste products were disposed of in unlined ponds.

• Contaminants leached into the groundwater, and surrounding soils.

• The contaminants migrated to the surrounding area including the residential area of Lincoln Park.

Background;

ContaminantsContaminants Ground

WaterSurface Water

Air Soil Other

Molybdenum • • •Molybdenum Compounds • • •Radium •Selenium • •Uranium • •Vanadium •Vanadium Compounds

•Lead • •

Cleanup methods used;

• Moving contaminated land into a lined impoundment.

–Excavation of soils and moving them to a confined site.

Cleanup methods used;

• Flushing and chemically fixing contaminates in the old “pond”In situ process, selected aqueous chemicals are injected into the soils,

After being contacted with contaminated material, the solution is collected using a pump – and – treat method.

Cleanup methods used;

• Constructing a ground water barrier around the soil consolidation area.

Ground water

Soil Consolidation area

Cleanup methods used;

• Constructing a permeable reactive barrier treatment wall

Alternative Methods

• In situ Vitrification– Immobilizing metal and radonuclide contaminants in the

subsurface.

• In situ redox– Injecting chemical reductants into the ground to create reducing

conditions that immobilize the contaminants.

• Electrokinetic systems– An electric field is applied to the soil to either stabilize the

contaminants in situ or to mobilize the for extraction.

• Photoremediation– Specially selected plants and grown and harvested after taking

up the contaminants.