AUBURN — A crane operator escaped with only an injury to his thumb Thursday morning when Route 136 gave way beneath his rig and sent piles of sand, rocks and asphalt — and his crane — crashing down an embankment toward the Androscoggin River.

Auburn Deputy Police Chief Jason Moen said the operator was OK.

The crash occurred at about 11:30 a.m. at a construction site on outer Riverside Drive in Auburn, also known as Route 136. According to the Maine Department of Transportation, approximately 200 feet of the road and three utility poles were damaged.

The crane was in its fourth day of pounding corrugated sheets of metal into the ground in an effort to buttress the wall facing the river, a DOT spokesman said Thursday. The crane, which was sitting in the middle of the nearly half-mile-long road that was under construction, toppled off a 40-foot cliff created by the collapse of the new road.

Gary St. Laurent, owner of St. Laurent & Sons in Lewiston, the contractor for the road work, said he's never witnessed anything like it in his 25 years in business.

"I've never seen it," he said.

St. Laurent subcontracted the crane work to H.B. Fleming Co. in South Portland and only had two workers at the site at the time of the collapse, he said.

The $636,930 reconstruction of 0.43 miles of Route 136 was halted in June after a portion of the southern end of the stretch of road slipped into the river. The project was expected to resume after the middle portion had been stabilized with the sheets of metal. Roughly 150 feet of a 200-foot-long section had been completed by Thursday.

At the time of the mishap, "The crane was driving support piles into the riverbank when the slide occurred, toppling the crane and utility poles," MDOT's statement said.

A portion of the road has actually washed into the river and creating a small island of road debris.

The metal guardrail along the river side of the road lay twisted and bent for the length of the collapse.

A firefighter at the scene said it "looks like a $1 million accident."

Engineers at MDOT are back at the drawing board reviewing their options to determine the best course of action, spokesman Mark Latti said.

The state had purchased land from abutters after the initial collapse two years ago. Officials had tried to limit the effect on abutters at that time by keeping the road as close as safely possible to the river, Latti said.

Meanwhile, St. Laurent said his company's work has been put on hold until a fix is found. Only 8 feet of the new road remains where the crane had been, he said.

Crews from Central Maine Power Co. were called because when the crane fell it took out the power lines along the road. A spokesman for the utility said Thursday afternoon that 33 residential customers in Auburn and Durham had lost power due to the collapse and all were expected to be switched to other circuits by later in the afternoon.

Traffic was rerouted onto Jordan School Road from Auburn, and onto Stackpole Road in Durham until further notice.

This portion of Route 136 has been under repair since Sept. 24, 2008, when a 120-foot section of the road washed into the Androscoggin River. At the time, MDOT said the collapse was due to something known technically as circular slope failure, which occurs when a stream or river slices into the lower half of a bank, undercutting it and causing it to collapse.

When the road collapsed two years ago, about 20 feet of the shoulder slid into the river, leaving the guardrail hanging there in the air.

Route 136 serves as the main connector between Auburn and Freeport, and is considered one of the busiest thoroughfares in the area.