State prosecutors say an elaborate marijuana growing operation at a gold mine near Manley may have been around for more than 20 years. Investigators this week seized 636 mature marijuana plants and 50 pounds of processed marijuana at the site off the Elliott Highway. Prosecutors filed additional charges Thursday against the suspected operator, 49-year-old John T. Larson of Fairbanks. Prosecutors say the operation was worth $2 million per year. Prosecutors say Larson went to elaborate lengths to hide the marijuana grow, with hidden rooms and a filtering system that removed the odor of marijuana but kept the heat of the grow lights from melting snow outside. Prosecutors say a tip led them to begin an investigation.

(Associated Press)