Abandoned Mine Reclamation
Historical mining activity, whether for coal, clay, limestone or other minerals, can impact the surface of the earth years after extraction is finished. Impacts can include ground surface subsidence, acid mine drainage, slope instability, unsafe highwalls and coal refuse piles.
S&ME has been providing abandoned mine land evaluation and remediation investigation and design services for well over 30 years. Completed projects range from damage evaluation for an individual house to the design of a grouting remediation program for miles of interstate highway. S&ME frequently performs historical research to evaluate the extent and depth of documented mines and coal seams. Along with reviewing historical sources, our professionals will walk a project site or corridor looking for signs of mining impacts such as subsidence features, mine shafts, unnatural terrain, landslides and discolored streams. When warranted, we perform a subsurface investigation including soil borings, rock coring, test pits. Direct observation methods may be supplemented with geophysical exploration when the conditions appear to be favorable.
We have designed extensive underground mine void grouting programs for numerous buildings, interstate highways and local roadways. We frequently perform risks assessments to determine if grouting is warranted relative to the nature of the project and mine condition. During the grouting process, S&ME can provide staff to log the bore holes and to document grout takes. Using grout take information, modifications can be made to the program. We have depicted grout take information using GIS data bases.
In addition to subsidence related impacts, S&ME has prepared designs for the remediation of surface mining impacts. The projects typically involve regrading heavily disturbed ground to control storm water runoff, eliminate highwall hazards, reduce infiltration and subsequent acid mine drainage generation, and allow vegetation to be established. Where acid mine drainage is impacting surface water, we have designed passive treatment systems such as wetland basins and anoxic limestone drains.
Mining related projects that S&ME has experience with include:
- Underground mine collapse and surface subsidence, as well as evaluating future subsidence risk;
- Design of underground mine remediation by grouting and overexcavation, including the use of dynamic compaction to improve mine spoil;
- Abandoned mine shaft hazard mitigation, including mine seals, mine drains, and stabilization against subsidence;
- Design of surface mine reclamation to improve land disturbed and mitigate residual hazards of past mining activities including bare and unvegetated waste piles, severe erosion, dangerous highwalls and slope instability;
- Design of the closure of slurry and wash impoundments including management of fine and coarse coal refuse;
- Design of treatment systems to mitigate acid mine drainage seeps including wetland basins and limestone channels;
- Restoration of stream channels impacted by mining including natural channel design and flood plain improvements.
In addition to design, S&ME routinely provides construction phase services including observation and testing, construction administration and laboratory testing of proposed grout mixes. Finally, S&ME can prepare any required environmental permit applications required for this work.