Gov. Bill Ritter shoveled the last bit of coal into what's believed to be one of the last hand-operated, coal fired furnaces used to heat a school in Colorado.

Soroco middle and high school will now be heated with a furnace that operates on woody biomass along with a geothermal heating system. New energy efficient lights are also being installed.

The upgrade, marked Monday with Ritter's visit that included a school-wide assembly, is part of a $4.1 million effort to improve energy efficiency in South Routt School District schools.

Ritter said the new system will save $15,000 a year in maintenance and utility costs and will emit 977 fewer tons of carbon dioxide annually.