The Shasta King Mine is an inactive copper mine located in steep, inaccessible terrain in Northern California. The mine contains five main portals that historically were major contributors of acid rock drainage to West Squaw Creek tributary to Sacramento River. Two of the main portals were sealed using concrete bulkheads in 199.; However, leakage around the bulkheads continued to result in Clean Water Act violations and litigation. The mine owner, Mining Remedial Recovery Company (MRRC), retained VESTRA staff to design a secondary seal to be installed adjacent to the existing leaking seal, obtain the necessary permits to install the bulkhead, and to complete the work.