Already, the new Lively Grove underground mine is producing some of the 6.3 million tons of high-sulfur coal that will be burned annually in the nearby supercritical power plant. Coal is being stockpiled in preparation for the commercial operation of 800-megawatt Unit 1. The twin second unit is scheduled to go on line next summer, perhaps sooner. Drawing upon a reserve base of 200 million tons, the mine has a projected life of 30 years.

Power plant construction is starting to wind down after hitting a peak in the past couple of years, when about 3,400 employees dotted the project site near Marissa in Washington County. “In 2009 and 2010, we were the biggest construction project in the country,” said Raj Rao, chairman of the PSEC management committee and president and CEO of the Indiana Municipal Power Agency, a joint action agency based in Indianapolis. IMPA is among eight public power co-owners of Prairie State. Peabody retains a 5% stake in the project.

Since construction got under way several years ago, Prairie State’s estimated price tag has doubled, and now is capped at about $4 billion. Still, Rao says he is proud the project is being financed without “a dime from the federal government.”

Prairie State’s co-owners say the power plant will be one of the cleanest coal-fired generating facilities in the U.S. Carbon dioxide emissions are expected to average about 15% less than the typical U.S. coal plant.

The plant will generate enough electricity to serve some 2.5 million families in five states and produce about $785 million in annual economic benefits for Illinois, an Illinois Basin state whose coal production is on the upswing after two decades of decline and stagnation following Congressional passage of the Clean Air Act Amendments in 1990.

Rising from the surrounding countryside, Prairie State’s sheer size is impressive. It boasts a 700-foot-tall stack, 70 ft higher than the Gateway Arch in St. Louis, about 40 miles away.

Approximately 450 full-time jobs will be created by the project, about three-fourths of them at the coal mine.