MAcid rock drainage (ARD) at construction sites in Korea has been an environmental concern due to the high acidity associated with this phenomenon and the release of toxic elements at high concentrations. This research covers the follow: 1) evaluations and classifications of the ARD generation potential of sulfide-containing rocks, 2) determination of the overall distribution of ARD-generating rocks on a scale of 1:250,000, 3) treatment technology for the reduction of ARD released from filling layers in embankments, and 4) construction technology for embankment structures for the safe utilization of ARD-generating rocks.
Originally, we completed eight ARD potential maps which cover the entire region of South Korea and which include locations of abandoned metal mines on a scale of 1:250,000. From a practical standpoint, we developed a new time- and cost-effective method using a handheld X-ray fluorescence (XRF) to determine sulfur (S) contents, and we classified ARD potential rocks in correlation with NAG pH measurements. This provides a guideline for the rocks to be excavated during civil construction works depending on the application strategy (aggregate, embankment) and their acid-generating potential. In addition, we tested the feasibility of an alkali phosphate treatment to reduce ARD on the basis of column experiments and optimized the coating/neutralization treatment for successful slope re-vegetation and the construction of safe embankment structures. Finally, we carried out a pilot-scale field test of an embankment structure utilizing ARD-generating rocks and confirmed the stability and effectiveness of the embankment structure by monitoring ARD generation levels and vegetation changes.
