Half of General Motors Corp.’s global manufacturing operations will stop sending waste to landfills before 2011.

The initiative, announced today, has implications for 80 GM sites and comes as 33 operations recently stemmed the flow of landfill-bound waste. This brings to 43 the current total number of sites that have achieved such efficiency.

Reuse and recycling account for 96% of the materials that once comprised waste. Just under 4% is converted to energy, GM says.

While greening the environment, GM’s recycling program also generates nearly $1 billion in annual revenue, the auto maker says.

“GM is accelerating our efforts to be a leader in finding solutions to the environmental issues facing our world,” Gary Cowger, GM group vice president-global manufacturing and labor, says in a statement.

In a separate announcement that also offers insight to GM’s green sensibility, the auto maker declares 18 of its ’09 models achieve at least 30 mpg (7.8 L/100 km) in highway driving – more models than any other auto maker.