Monitoring SCO and Enhancement Activities
As part of its commitment to return the land to its agricultural use, HPS has crafted monitoring programs that will help ensure the steps toward mitigation and reclamation are working as intended.
First, HPS has proposed a Sand-Clay-Overburden Quality Assurance Plan that imposes requirements for the monitoring of the SCO mix prior to and after emplacement to ensure it has the desired properties. As the SCO exits the overburden mixing station, its mass and percent solids will be measured by a conveyor belt mounted scale and moisture content meter. As previously discussed, the ratio of sand-to-clay will be adjusted to mimic the hydraulic composition of native soils in the upper soil profile, ensuring that the reclaimed landscape will be consistent with pre-mining landforms. A composite sample of the SCO, collected from routine belt samples, will be analyzed daily to check and calibrate the belt scale and moisture content meters.
About ninety days after SCO is placed in the mine cut, the fill area will be tested to ensure it continues to exhibit the appropriate properties. Core samples will be gathered along the length of the filled mine cut at 250-foot intervals. Material will be gathered in 5-foot depth increments at each sampling locationand then analyzed for composition of sand, clay, moisture content, hydraulic conductivity, cohesiveness, and compressive strength.
If the results of the core sampling do not meet established metrics, HPS will allow for an additional 90-day period, collect another series of core samples, and re-assess. If, following the second sampling event, the core samples again do not meet the parameters, HPS will develop and implement an adaptive management plan approved by the Florida Department of Environmental Protection. An annual report will be provided to the Department of documenting the results of the SCO sampling program and any adaptive measures that were needed.
In addition to monitoring the SCO placement, HPS will monitor the success of the mitigation activities throughout the property—both in reclaimed mine areas and those that were avoided. This will be accomplished by field observations and qualitative monitoring to confirm that the areas are meeting the desired criteria. Within 30 days of completion of the proposed mitigation activities, an initial monitoring event will be conducted, followed by annual reporting. These qualitative monitoring reports shall include a brief description of any mitigation and maintenance work performed since the completion of the previous report along with a discussion of any current or anticipated modifications to the mitigation or maintenance program. The reports will also include the results of the vegetation monitoring, water quantity monitoring, a list of observed wildlife, and photographic documentation from the 18 permanent photography stations established throughout the enhancement areas.
Adaptive management, such as selecting alternate native plant species from approved planting lists to adapt to soil or hydrologic conditions, or slightly correcting or adjusting contours, may occur during the establishment period to ensure that created landforms and wetlands will achieve success criteriadesignated by state regulators for the HPS project.