Jonesville — After what witnesses described as a quick, deep boom, a cloud of dust seemingly rose out of the old Black River bridge before its metal infrastructure began to slowly fall to the ground Friday.

The demolition of the bridge, built in the 1930s, began Friday afternoon with the explosion of the western approach.

The goal of the demolition was to drop the bridge’s metal truss to the ground so it could be disassembled, Project Engineer Justin Reeves said.

“We were just trying to get the (metal) piece down,” Reeves said. “It’s fairly dangerous to disassemble it in the air.”

A four-lane replacement bridge spanning the Black River into Jonesville along U.S. 84 was constructed and opened in October 2008.

The explosion was initially scheduled for 2 p.m., but things fell into place quickly enough that the demolition crew was able to detonate the explosives at 1:35 p.m., Reeves said.

The highway was closed shortly after 1 p.m., and was back open for traffic by 2:15 p.m.

The state police also closed airspace surrounding the blast site, Reeves said.

Covered in dust following the procedure, President of Chicago Explosion Services Patrick Carney said things went well.

“The seismic measure was good, and the air blast at the top of the bridge was measured at 155 — that won’t even break a window,” Carney said.

Jonesville resident Jackie Rouse remarked that she thought the bridge would look a little more demolished, while onlooker Mildred Huffman said she expected to hear more of a boom.

“It is a piece of history gone,” Jonesville resident Naomi Adams said.

One of the eastern trusses is scheduled to be demolished at 5 p.m. today, some residence evacuations will begin at 4 p.m. and highway and street traffic will be closed at 4:30 p.m.

The center swing of the bridge is scheduled for demolition at 2 p.m. next Thursday, and the eastern approach to the bridge will be demolished at 5 p.m. next Saturday.

When the bridge was built, dirt from a nearby American Indian mound — at that time, the largest in Louisiana and the second largest in the North America —  was used to build the approaches.

Once the demolition is complete, archeologists will sift through the dirt for artifacts, and plans are under way to build a replica of the mound using some of the original dirt.