Sheridan Mine Fire Mitigation (Wyoming)
Problem:
A prairie fire ignited graded coal slack piles that were associated with completed AML reclamation projects, the most recent being the Monarch Coal Mine Subsidence.

Special Client Concerns:
Prevent vehicle travel across the burning coal slack located within the county road.
Prevent migration of the burning coal slack into the reclaimed portal located south of the county road.
Objective:
Properly encapsulate, isolate or extinguish all burning coal slacks.
To eliminate one or a combination of the 3 essential components of a mine fire:  oxygen, fuel source and heat.
Results:
Investigated; Construction Management; Monitoring.
Within the three days that PHC-REC personnel were on-site, burning coal slack and/or ash was properly encapsulated or contained per the construction methodology instructed by the AML.  A cut-off trench was constructed across County Road 106 to prevent vehicle travel across the burning coal slack located within the road.  Another cut-off trench was constructed to prevent migration of the burning coal slack into the reclaimed portal located south of the county road.
The construction methodologies used were encapsulation of the burning coal slack by excavating a pit, pushing the material into the pit and covering the material with adjacent soils.  Excavating "cut-off" trenches around random coal slack burn areas to prohibit further migration of the burning coal slack and restricting its fuel source within the trenched area.  Combining the encapsulation and trench methods and mixing the burning coal slack with adjacent soil materials (free of combustible materials).