In the late 1990s, Barr assisted Minnesota Power with alternatives analyses for expansion of their coal combustion residuals (CCR) surface impoundment at Laskin Energy Center in Hoyt Lakes, Minnesota. We sited, designed, and permitted a new surface impoundment for CCR, called “Cell E,” which was configured for construction in two phases. The initial phase served Minnesota Power from approximately 2000 through 2012. The second phase, consisting of a vertical expansion of Cell E as originally permitted, included the final design and permitting of the vertical expansion and construction oversight, all occurring in approximately 2011 and 2012. The vertical expansion extended the operating life of Cell E, which then ceased operations in 2015. Barr subsequently designed the Cell E closure, which occurred in 2016 through 2018. Closure monitoring continues.
This was the first geomembrane/geosynthetic clay-lined CCR surface impoundment permitted and constructed in Minnesota at the time of its initial construction. This liner system was selected to address the regional shortage of naturally occurring high-quality clay and to facilitate the impoundment construction within a single construction season, which in northern Minnesota is often limited to a six-month duration.