By John Hill

Journal Staff Writer

PAWTUCKET

In the early 1900s, power lines came to Slater Mill. Looms and spinning machines that had been powered by water wheels were instead energized by electric current. So, for the last century, those obsolete turbines sat still beneath the mill floor, rusting and filling with silt.

But Tuesday morning, Mike Desroches and Erik Andrews descended into that muck and, with a small pump, shovels and three chain lifts, hoisted the last major piece of one of the turbines out of the Blackstone River mud for a trip to a machine shop in Wilbraham, Mass., for its restoration, reassembly and rebirth as a Slater Mill power generator.

The restoration of the turbine, paid for with a $194,000 federal grant, is part of an overall $1-million renovation program at the 217-year-old Slater Mill.

Desroches and Anderson work for Swift River Hydro Operations, a Massachusetts company that runs water-power turbines and rehabilitates old ones. The Francis turbine they pulled up through a hole in the floor at Slater Mill was installed sometime in the 1860s, and Andrews says that even for Swift River, that was old.

“It’s really kind of typical,” Andrews said of the job. “But usually, there’s not as much muck and dirt.”

For decades, the Francis turbine, and another called a Jonval turbine, were left to rust in place. The mill staff made the Francis an exhibit anyway, cutting a hole in the floor over it and letting visitors see it through a thick plastic sheet that covered the hole.

“They’ve just been sitting under the building,” mill curator Andrian Paquette said. “We decided to do something to save them, instead of letting them rust away and disappear.”

The basement work space was warmed by large lamps that filled it with an orange light. The soundtrack of the work was a constant suck-suck-suck sound from a small pump that drew the muddy water from the inside. Andrews and Desroches would surgically pick the rust-tinged mud that had collected between the curved turbine blades.

When they freed it from the mud, they and Marjorie Bailey, another Swift River employee, hoisted it up through the hole in the floor, strapped it to a handcart and rolled it out a side door and onto a waiting flatbed trailer.

Paquette said the Jonval turbine, similar to the Francis, was too badly rusted to be restored. The rust on its exterior may be sandblasted anyway, he said. Paquette said the plan is for the Francis turbine to be reinstalled by the end of summer.

It could generate electricity in the building, he said, but not to run any of the weaving machines on display in Slater Mill. That type of demonstration is already being done in the Wilkinson Mill next door, Paquette said, and some of the machines in Slater Mill are from after the turbine was out of use.

“We’re a little more concerned about vibration in this building,” he said.

In their day, the Francis and Jonval turbines were an evolutionary leap in water power, more than three times as efficient as larger water wheels and less than half their size; the Francis turbine is four feet across. Their curved vanes were bolted to a central rod, looking like the front of a jet engine. Unlike water wheels, they lay on their sides, and water poured into them at an angle, striking the vanes and spinning the wheel.

Before 1860, the Slater Mill turbine pit held old-style water wheels, Paquette said. With the turbines removed, the site can be excavated for relics of that era.

“You’ve got a lot of layers of time in there,” he said.

jhill@projo.com