The Army Corps of Engineers is pressing forward with the demolition of rock formations in the Mississippi River using dynamite, after a $5.7 million stimulus project failed to remove them.

In 2009, the federal agency committed millions of dollars from the Obama administration's economic stimulus plan to try an experimental grinding process to clear the rocks, known as pinnacles. The method is supposed to be less expensive and damaging to the environment than dynamiting.

But the attempt proved futile after one effort in 2011 and another this year, totaling about four weeks of work. The project has now been called off.

The Army Corps is working on an expedited effort to use explosives to remove the pinnacles, since the formations are making it difficult for commercial operators to navigate the river as waters continue to recede. The agency predicts the low waters will impede navigation by Dec. 11.

"It's been known for some time that the pinnacles need to be removed," said Merritt Lane, president of marine transport company Canal Barge Co. "The pace of progress on that has been too deliberate from our perspective" (Zajac/Ivory, Bloomberg, Dec. 4). -- JE