About 120 anthracite miners were forced to quit two tunnels of the vast Dodson colliery of the Weston-Dodson Coal Co. today because of an underground mine fire. Mining engineers continue to search for the underground fire in the No. 6 mine, without much success. Company officials said they have been unable to locate the fire. The blaze was uncovered when a noticeable amount of carbon dioxide gas was detected during a routine check of the air in the mine.