Site Description and History

Cove was named for its remote location in the foothills of the Chuska mountain range, tucked away in the Carrizo, Lukachukai and the beautiful mountains in northeastern Arizona, in the Northern Agency of the Navajo Nation. Local industries include farming, traditional gathering activities, grazing livestock, and hunting, but most residents work outside the community. Culturally significant areas, including ceremonial spaces, and geologic features such as mesas, overhangs, and caves, characterize the landscape setting and rich natural resources.

From the late 1940s to the 1980s, Kerr-McGee Corporation mined more than seven million tons of uranium ore on or near the Navajo Nation. About 32 of these mines are located in the Cove. The area being assessed by EPA includes the abandoned uranium mines (AUMs) within the Cove Chapter boundary and the resulting contaminated areas. This area includes 50 AUMs within Cove Wash watershed.

• Current investigations

  Investigations into the extent of mine impacts were implemented as soon as settlement funds were received in January 2015. There are approximately 24 additional abandoned uranium mines in the Lukachukai Mountains that are not covered by the settlement because they were not operated by Kerr-McGee. EPA is working to identify additional responsible parties to pay for cleanup of these mines.

  EPA is conducting several investigations within the Cove site to include a watershed assessment, a mine category assessment protocol (MCAP), aerial radiological surveys (ASPECT) and an irrigation system and farm plot study.

• Cove Wash Watershed Assessment

  The Cove Wash watershed is approximately 47 square miles, and contains approximately 52 miles of tributaries. The watershed supports diverse wildlife and plant communities, including perennial wetland habitats, and is home to protected species such as Mexican spotted owl and American dipper. Livestock grazing activities move seasonally between the lowlands and steep, mountainous areas.

  The Cove Wash watershed is not currently a designated drinking water source, but may have been historically used by residents before drinking water was provided by a municipal source 20 years ago. Resident farmers also use these streams for crop irrigation and livestock watering. Wells sampled in the past have shown exceedances in drinking water standards for Total uranium, and have been decommissioned for domestic use.

  The watershed assessment includes sampling surface water, seeps, springs, wells, and sediment throughout the watershed over the course of several years and several seasonal conditions. Sampling is used to pinpoint contaminated areas and to understand baseline conditions prior to waste removal actions. The assessment also includes biological surveys, and inventories of plants and herbs important for traditional or ceremonial uses.

• Mine Category Assessment Protocol

  The purpose of the mine category assessment protocol (MCAP) is to develop and implement a systematic method for assessing and surveying AUM sites to determine and evaluate removal factors impacting future site work. MCAP will result in a ranking system for prioritizing Removal Site Evaluations in upcoming years.

• Airborne Spectral and Photometric Environmental Collection Technology (ASPECT)

  The USEPA sent a team to perform an aerial radiation and imagery survey of the Navajo Nation abandoned uranium mines in the Cove Chapter area. This area includes the Lukachukai Mountains, containing the Kerr McGee/Tronox associated mine sites as well as the drainages and flat lands north of the mountains, extending past the Cove Chapter house. The survey was performed by a white low-flying USEPA airplane with twin engine propellers during one week in December 2014. The purpose of this survey was to identify potential additional radiation coming from the dozens of old mines scattered over many miles around the Cove Chapter area. The survey will also assist EPA and Navajo Nation (NNEPA) prioritize areas for additional environmental assessment activities that will be used to determine if these sites pose a risk to people in the area and, if so, what measures should be taken to minimize that risk.

• Irrigation System and Farm Plot Study

  Based on community concerns, EPA will investigate whether active and historic irrigation systems (irrigation canals and storage ponds) and farm fields may be impacted by mines, and whether there may be associated human health risks through ingestion of agricultural crops that are grown in sampled areas using irrigation system and Cove Wash surface water.