The many levels of the massive Mississippi River cleanup are as thick as the oil itself.

But while there are plenty of hurdles, Coast Guard officials say the effort is moving forward.

"The river's cleaning itself out, and we're catching up, we're collecting the oil," said Coast Guard Capt. Lincoln Stroh.

And the numbers reveal the grand scope of the project.

More than 1100 responders have stretched upwards of 200,000 feet of containment boom across 19 key sections of the river.

The work area is more than 100 miles long, from New Orleans, to the mouth of the Mississippi.

"We're seeing more water without floating oil on it, and what that has allowed us to do is to relocate our resources to apply to those areas that have greater concentrations of oil," said Paul Book of American Commercial Lines. 

The Coast Guard makes routine flyovers, getting an eyeball gauge of the progress.

But tonight, they take that a step further.

"We're bringing one test ship up from the gulf,” Stroh said. “It's going to be like a litmus test to see how clean the river is, and it's going on a slow bell up to New Orleans, and it'll probably be there tomorrow morning, 8, 9 o'clock, and we'll go out there and look at it, see how much oil is on it, as a litmus test to see how soon we can open up the river."

As the cleanup continues so does the investigation into the collision that caused the spill.

Coast Guard officials confirm the same towing company that didn't have any properly licensed tugboat operators on board at the time of the crash, was involved in another incident recently.

Officials say another tugboat owned by DRD Towing crashed into another ship near Westwego several days ago, sinking the tugboat.

"That's part of the ongoing investigation too to look at that and to see how that impacts on the current investigation," Stroh said.

But the Coast Guard points out the priority is the cleanup and getting more ships moving on the river.