projects such as hiwassee dam and fontana dam have been a focus of the company as well, also see their work with tennessee valley authority. with regard to dam remediation and upgrades, slot cutting projects are the company's main focus. it is akin to slicing a concrete dam like a piece of birthday cake. the technique is simple but very difficult, rotate a loop of cable strung with diamond embedded beads through the structure — essentially, like using a loop of fishing line to cut a cake. slot cutting is employed to create expansion joints in dams afflicted with compression stresses due to concrete swelling. alkali aggregate reaction, or aar, is a chemical reaction in concrete created where the aggregate has a high silicon dioxide content. the southeast usa is one such region, and dams in that area require periodic slot cuts to avoid cracking, leakage, and interference with mechanical components such as gates and turbines. the time intervals depend on the aar specifics of each structure, but 10 years is an average.