Gibson Project:
The Gibson project treats drainage from an abandoned strip mine extending for over a mile on the northeast side of the Little Laurel Run Valley. The GH1 discharge averages about pH 3.7, 1.5 mg/L iron, 3.3 mg/L aluminum, and acidity 40 mg/L at a flow averaging 150 gal/min.
The system was designed by Alder Run Engineering using an EPA 319 grant of $43,098 in 2011-2012. Construction followed in 2014-2016 with an EPA 319 grant of $535,733. The system consists of a small dam on the discharge, an inflow settling pond feeding two flushable limestone beds with outflow settling ponds. Quarterly monitoring by CCWA members shows net alkalinity about 2/3 of the time with up to 10 mg/L acidity the remainder of the time, and metals < 1.5 mg/L. The systems are designed to automatically flush weekly but at times this sequence has not been followed.
The system was designed by Alder Run Engineering using an EPA 319 grant of $43,098 in 2011-2012. Construction followed in 2014-2016 with an EPA 319 grant of $535,733. The system consists of a small dam on the discharge, an inflow settling pond feeding two flushable limestone beds with outflow settling ponds. Quarterly monitoring by CCWA members shows net alkalinity about 2/3 of the time with up to 10 mg/L acidity the remainder of the time, and metals < 1.5 mg/L. The systems are designed to automatically flush weekly but at times this sequence has not been followed.
In 2024, the limestone beds were cleaned experimentally by
Hedin Environmental, improving the performance.
Hedin Environmental, improving the performance.
