The Historic Lisbon Valley Mining District (Site) is located southeast of La Sal in San Juan County, Utah. Miners discovered copper in the area in 1892 and they expanded their mining activities in the late 1920’s after the additional discovery of ore bodies containing uranium and vanadium. The area remained a significant producer and area of exploration until mining operations dramatically slowed in the 1980’s.

In 2022, EPA, BLM and the State of Utah identified two abandoned mines where recreational human exposure to mine waste is evident, the downstream migration of mine waste is significant during flash floods and no apparent remediation has occurred. These two abandoned mines are the Radon Mine and the Columbia Shaft.

EPA will conduct a CERCLA Time-Critical Removal Action at these two locations in the Fall 2022 to control erosion and limit human exposure to contaminated mine waste.

Radon Mine

1. Remove radioactive metal debris found on surface of waste pile.
2. Regrade the waste pile and install erosion control features.
3. Pull toe of the waste pile out of the ephemeral drainage.
4. Restrict visitor access until new vegetation is established.

Columbia Shaft

1. Regrade the waste pile and install erosion control features.
2. Restrict camping and access to the waste pile.

Radon Mine

• Mobilize equipment and personnel.
• Set the Site up for construction activities.
• Begin excavating the waste pile.

Radon Mine

EPA's Response Team mobilized to the Radon Mine on October 10, 2022. A detailed radiation survey was conducted prior to commencing work and the Team set up the Site by:

• Re-grading the historic access road to the Radon Mine and cutting back the brush along the road to allow better access for large equipment.
• Establishing an Exclusion Zone, a Contamination Reduction Zone (decontamination area for personnel and equipment) as well as a Support Zone using safety fence. A decontamination trailer was placed in the Contamination Reduction Zone and EPA's Mobile Emergency Operations Center (MEOC) was placed in the Support Zone. A tank to fuel heavy equipment and a water trailer was placed along the boundary between the Exclusion Zone and the Support Zone. The fuel tank will be refilled as needed while the water trailer will be refilled several times each day as needed.
• Deploying dust tracking devices to monitor air quality levels in both the Contamination Reduction and Support Zones. 

The Response Team then cleared and saved organic material from the area where material excavated from the waste pile will be placed and began excavating the pile. The Team started by removing the upper portion of the metal debris on the slope as well at a hot spot on the pile's flank. The crew then began removing the top 12-15 feet of material along the crown of the waste pile to lower the elevation at which the top of a ramp down to the ephemeral drainage will eventually be constructed. 

Radon Mine

• Excavate the top of the waste pile along the slope that leads down to the drainage.
• Place the material that is excavated along the old terraces that were constructed at the abandoned mine and back away from the drainage.

Radon Mine

EPA's Response Team removed a section of the waste pile that is approximately 15' deep and 25' wide along the entire crown of the eroded slope. This activity will allow for easier access to the slope itself and to access the toe of the pile. 

The mine waste that was excavated was placed back away from the slope and used to begin establishing a more gentle gradient. The entire waste pile will eventually be regraded to better control erosion and keep the material from entering the drainage and migrating off-Site.

Radon Mine

During the next Operations Period (October 24-30), EPA's Response Team will continue excavating the eroded slope of the waste pile and create a path for heavy equipment down into the drainage to access the toe of the pile.

Radon Mine

• Continue excavating the crown of the waste pile above the drainage.
• Place the mine waste that is excavated from the pile back away from the drainage on top of the waste pile and along the terraces that were constructed at the abandoned facility.
• Begin to construct a temporary ramp for heavy equipment to access the toe of the pile and the drainage.

Radon Mine

EPA's Response Team removed a second lift or step from the crown of the waste pile. This second lift was again approximately 15' deep and 25' wide. The two lifts that were excavated will allow for easier access to the slope itself and to the toe of the pile. 

The mine waste that was excavated was placed back away from the slope and used to continue establishing a more gentle gradient. The entire waste pile will eventually be regraded to better control erosion and keep the material from entering the drainage and migrating off-Site.

The Team began construction of a ramp across the remaining face of the waste pile and down to the drainage which will allow heavy equipment to access the toe of the pile.

Radon Mine

EPA's Response Team will complete construction of the access ramp down to the drainage and will begin pulling the toe of the pile back away from the drainage.

The crew will remove the metal debris that remains on the slope and in the drainage. The top of the debris pile was removed during the first Operations Period. The remaining metal debris that is removed will be buried in the regraded waste pile.

The Team plans to largely complete construction activities at the Radon Mine by Thanksgiving and initiate construction activities at the Columbia Shaft after Thanksgiving.

Radon Mine

• EPA's Response Team will complete construction of the access ramp down to the drainage.
• EPA's Response Team will begin pulling the toe of the pile back away from the drainage and continue excavation across the pile to make a more gentle slope.
• The crew will remove the metal debris that remains on the slope and in the drainage. The metal debris that is removed will be buried in the regraded waste pile.

Radon Mine

The access ramp to the drainage was completed.

The crew excavated over 2500 yds3 of tailings and placed them on the top of the pile.  These tailings were integrated into the regraded pile.

The crew began to pull waste from the toe of the pile out of the drainage.

The crew generated >250 yds3 of rock from on-site to be used as rip-rap for stabilization.

Radon Mine

The EPA Response Team will complete pulling the tailings pile out of the drainage and establish a rough completion of the final grade.

The EPA Response Team will begin installing drainage control features and armoring the toe and critical slopes of the waste pile. 

Radon Mine

• Complete repair of the culvert and rip rap its outfall.
• Begin to regrade to toe of the pile.
• Continue excavating the crown of the waste pile above the drainage.
• Place the mine waste that is excavated from the pile back away from the drainage on top of the waste pile and along the terraces that were constructed at the abandoned facility.

Radon Mine

EPA's Response Team replaced the last section of culvert before its outfall. The old culvert was not connected and was damaged. Rock collected from along the terraces of the former facility was used to rip rap its outfall and down the slope of the waste pile.

The Team removed mine waste from the toe of the pile starting at the furthest point downstream and worked its way upstream. The crew regraded the pile and moved its new toe back away from the drainage to a point that is at least 10 vertical feet from the low point in the adjacent ephemeral stream.

Radon Mine

EPA's Response Team will continue moving the toe of the waste pile out of the drainage and continue regrading the waste pile itself.

Weather permitting, hydro-mulch will be used to control erosion and reseed the newly regraded pile.

Radon Mine

• Finish pulling the toe of waste pile out of the ephemeral drainage.
• Remove mine waste from the ephemeral drainage to the extent practical.
• Create a runoff control ditch across the face of the pile.
• Complete rough grade of the waste pile.

Radon Mine

EPA's Response Team pulled the toe of the Radon Mine waste pile completely out of the ephemeral drainage and above a conservative 10’ deep floodway. The toe was pulled back to native bedrock in many locations and rock was used to protect native soil from erosion. Mine waste removed from the drainage was moved to the top of the pile.

The Team left the drainage and regraded their access ramp into a runoff control ditch. The entire waste pile was graded to better control erosion and keep mine waste from entering the drainage and migrating off-Site.

Radon Mine

Response Operations at the Radon Mine are largely complete. EPA's Response Team will reseed the regraded waste pile with hydro-mulch and place boulders in front of the gate to the mine to best restrict access until vegetation is established.

Columbia Shaft

The Response Team will move equipment and resources including communications to the Columbia Shaft at the beginning of the next Operations Period. Field activities will be paused for Thanksgiving.

Radon Mine

• Seed the regraded waste pile using hydro mulch.
• Install gate with lock at bottom of access road.
• Move equipment to Columbia Shaft location.

Radon Mine

The Response Team procured a seed mix recommended by BLM and spread the seed on all disturbed areas using a hydro mulch mix which contained an organic amendment, mulch and a tackifier.

A ranch gate was installed across the mine access road at the point where it leaves the the County Road. The gate will be locked until vegetation on the waste pile is established.

Columbia Shaft

The crew moved its equipment, decontamination trailer, command post and other resources to the Columbia Shaft.

Radon Mine

EPA's Response Team plans to spread another layer of protective hydro mulch on top of the seed, install additional erosion control features (rocked water bars and waddles) and place radiation warning signage provided by BLM.

Columbia Shaft

The Team will begin regrading the Columbia Shaft waste pile.

Radon Mine

• Maintain Site security.

Columbia Shaft

• Establish work zone and support areas.
• Remove the first lift of waste material.

Radon Mine

EPA's Response Team insured that the gate to the mine access road (which is located where the access road leaves the county road) remained locked and secure. The lock is not permanent but will remain in place for 1-3 years until vegetation is established on the regraded waste pile.

Columbia Shaft

The Team delineated its work zone as the entire waste pile and established a decontamination area as well as a support zone.  The decontamination area and support zone are located down the Columbia Shaft access road on the other side of a rocky ridge from the waste pile. Temporary fencing was used to designate work areas and limit damage to desert vegetation and cryptogamic soil.

The crew removed the top 10 feet of waste material along the entire crown of the waste pile's face. This  material was hauled a short distance to the top of the waste pile and deposited along a rock face that was quarried when the shaft was developed.

Radon Mine

The Response Team will finish installing warning signs as well as erosion control waddles and rock water bars. The crew also plans to add an additional layer of hydro mulch on top of the seed and mulch that was previously applied.

Columbia Shaft

The Team will continue regrading the waste pile. The slope of the finished grade will ideally be 3:1 but the volume of material being removed and the space available to place it may not make that possible.

Radon Mine

• Apply second layer of hydro mulch.
• Complete runoff control ditch with water bars.
• Install warning signs and maintain Site security.

Columbia Shaft

• Remove the first and second lifts of waste material.

Radon Mine

EPA's Response Team added a second layer of hydro mulch on the regraded waste pile to improve erosion control and increase the chances for seed germination. Once this was accomplished, the Team completed its conversion of the access ramp to the drainage into a runoff control ditch by installing water bars.

Warning signs were placed on the waste pile and on the gate leading up to the waste pile.

Columbia Shaft

The Team continued removing mine waste from the face of the waste pile and moving it to the top of the pile along a rock outcrop that was quarried when the mine was developed.

Radon Mine

EPA’s Response Team will make sure the gate to the Radon Mine remains locked.

Columbia Shaft

The Team will continue regrading the waste pile. The slope of the finished grade will ideally be 3:1 but the volume of material being removed and the space available to place it may not make that possible.

Columbia Shaft

• Remove the first and second lifts of waste material.
• Begin grading and excavation in the drainage channel.
• Begin removing waste material in the adjacent slope to the first and second lifts. 

Columbia Shaft

The Team continued removing mine waste from the face of the waste pile and moving it to the top of the pile along a rock outcrop that was quarried when the mine was developed. 

The Team began grading and excavation in the drainage channel. 

The Team constructed an access ramp and began excavation of mine waste on the adjacent slope.  

Columbia Shaft

The Team will continue regrading the waste pile. The slope of the finished grade will ideally be 3:1 but the volume of material being removed and the space available to place it may not make that possible.  The 3rd lift is planned to begin next week.  The drainage channel will continue to be constructed in the upcoming week.

Columbia Shaft

• Begin removing the 3rd lift of waste material in the drainage.
• Continue constructing drainage channel on western edge of waste pile.
• Demobilize for the Christmas and New Year Holidays.

Columbia Shaft

The Team continued removing mine waste from the face of the waste pile and moving it to the top of the pile along a rock outcrop that was quarried when the mine was developed. 

The Team continued grading and excavation in the primary drainage channel. 

The Team continued excavation of mine waste on the adjacent slope.  

Columbia Shaft

The Team will continue regrading the waste pile. The slope of the finished grade will ideally be 3:1 but the volume of material being removed and the space available to place it may not make that possible.  The 3rd lift will continue to be excavated and the the drainage channel will continue to be constructed.

Note: The Team will demobilize from the Site Dec 24, 2022 through January 1, 2023 for the Christmas and New Year holidays.

Columbia Shaft

• Remobilize crew after the Christmas and New Year Holiday break.
• Complete removal of the 3rd lift of waste material.
• Begin installing liner and rip rap in the primary drainage channel on western edge of waste pile.

Columbia Shaft

EPA's Response Team remobilized to the Site on January 2, 2023. Several crew members were delayed getting to the Site until January 3 due to winter weather and difficult travel conditions. The Team cleared snow in order to access the Site.

The Team completed its third lift excavating waste material from the face of the waste pile. This material is being moved to the top of the pile and the entire pile is being regraded to a 3:1 slope as the Team works its way to the drainage. All three lifts that have been excavated were cleaned up during this Operations Period in preparation for the construction of slope breaks.

The Response Team installed a liner in the primary drainage ditch on the western periphery of the waste pile and began installing rip rap. Rock for rip rap was collected from the rock face that was quarried when the mine was developed.

Columbia Shaft

The Team will continue regrading the waste pile. The slope of the finished grade will be 3:1. A fourth and final lift of waste material will be excavated along the toe of the existing waste pile. Four slope breaks will be established on the regraded waste pile at the location of these lifts and a series of one primary and 2 secondary armored channels will be created to help control erosion and move surface runoff off of the regraded pile.

Columbia Shaft

• Begin removal of a 4th and final lift of waste material along the toe of the waste pile.
• Complete installation of rip rap in the primary drainage channel on western edge of waste pile.
• Begin construction of 2 secondary drainage channels and 4 slope breaks.

Columbia Shaft

EPA's Response Team began excavation of the final and 4th lift along the slope of the historic waste pile. This lift is not a continuous excavation but rather a segmented series of digs along the toe of the waste pile and creek, around bedrock formations, existing vegetation and topographic features. From this lift, the Response Team will be able to reach down to the banks of the creek and remove contaminated material.

The Team placed rip rap on the liner that was installed in the primary drainage channel and began constructing several secondary channels to help move runoff off the regraded pile.

Three of the four planned slope breaks were graded during this Operations Period.

Columbia Shaft

The Team will complete regrading of the waste pile including construction of armored drainage ditched and slope breaks. Organic material that was salvaged early in the construction process will be spread on top of the regraded waste pile and boulders will be used to prevent access to the pile until Spring, 2023.

Columbia Shaft

• Complete regrading of the waste pile including construction of armored drainage ditched and slope breaks.
• Spread organic material that was salvaged early in the construction process on top of the regraded waste pile.
• Use large rocks and boulders to prevent access to the pile until Spring, 2023.
• Demobilize from the Site for the Winter.

Columbia Shaft

The Response Team nearly completed regrading of the waste pile and construction of armored drainage ditched and slope breaks. A significant storm impacted the Site on January 17, 2023 and a few final grading details were left for the Spring.

Organic material that was salvaged early in the construction process was spread on top of the regraded waste pile.

The Team decontaminated and demobilized all equipment, placed large rocks across the access road and demobilized on January 21, 2023 for the Winter.

Tasks that remain to be completed at the Columbia Shaft:

1. Final grading needs to ensure surface water runoff flows where it is intended.

2. A rocked channel will be installed from the lowest slope break to below the toe of the waste pile.

3. Disturbed areas will receive hydroseed/mulch.

4. Vehicular access to the pile will be permanently closed. Signage will be placed as directed by EPA.

5. Post-Removal Unmanned Aerial Systems data will be collected and analyzed.