A Port Huron paper mill will be laying off over twenty full time workers by the end of the year. Domtar Paper announced Thursday that they will be shutting down one of its production lines in Port Huron. Craig Timm, public affairs manager for Domtar, says a machine that produces uncoated business paper will be permanently closed. Timm tells WPHM the Port Huron mill will continue to produce specialty papers on its three other machines. The closure is anticipated to occur by November 15th of this year, affecting 22 full time positions. Timm says the decision is due to market conditions and a decreasing demand for uncoated free-sheet paper. A paper machine at another Domtar Facility in Arkansas is also slated to close this year. Following the machine closure, the Port Huron mill will employ approximately 212 people.