In a tree-surrounded grassy hollow a half-mile from Collins Correctional Facility, volunteers have spent two years tapping the earth with plastic poles in search of square concrete slabs that sank out of sight long ago.

When one is located, it is gently levered to the surface with a crowbar, cleaned with a bristle brush, soap and water, and reinstalled on a firmed-up bed edged with gravel.

So goes the painstaking work of restoring the anonymous graves of 1,200 patients from Gowanda Psychiatric Center. They were buried in Wheater Road Cemetery between 1898, when the hospital opened, and 1994, when it closed. The site reopened as the Collins and Gowanda correctional facilities in 1995.

The only markings on the flat gravestones are a number or a wreath, signifying that the deceased was Protestant, or a cross, denoting Catholic. Records containing the names of those buried in the cemetery were lost after the hospital shut down.

The restoration was undertaken by People Inc., an Amherst-based agency serving Western New York’s developmentally disabled population, to finally give honor and dignity to the facility’s unidentified and unmourned former residents.

Students from Siena College and St. Bonaventure University are doing the work, under the direction of David Mack-Hardiman, People Inc. training director, with assistance from the Collins state prison and Gowanda historian Phillip Palin.

“We did a lot of research on how to do this properly,” Mack-Hardiman said. “We don’t want to do any harm.”

The nonprofit agency learned of the Collins graveyard and similar sites off Route 62 in Gowanda and Route 39 in Perrysburg, site of the former J. N. Adam Developmental Center, from a 2002 story in The Buffalo News.

It reported how the cemetery had been uncovered by local members of Operation Dignity, a national movement to honor tens of thousands of institutionalized mental health patients buried in unmarked or numbered graves. Dense thickets of weeds and berry canes were cleared, and Collins Correctional Facility agreed to maintain the graveyard’s four quadrants.

Support for the restorations was slow in coming, Mack- Hardiman said, because mental illness has long carried a stigma, and the institutionalized were deemed “not so worthy” of proper burial by the state that cared for them and even by their families.

“What took time was getting people to understand what we were doing,” he said.

The project gained momentum when People Inc. forged an alliance with the Cattaraugus County Mental Health Association and prison officials.

“We said, ‘Sure. Definitely. These are people we need to remember,’ ” said Jim Thompson, Collins Correctional Facility deputy superintendent.

After the restoration of 550 graves in the Route 62 cemetery, a “ceremony of remembrance” was held in 2007 to install a monument honoring the dead from the Gowanda and J. N. Adam hospitals.

Mack-Hardiman said he foresees a similar observance at the Wheater Road location, although restoring the remaining gravesites will take at least two more years.