A $3.4 million abandoned mine water treatment project along Indian Creek in Saltlick, Fayette County, was temporarily incapacitated by vandals who opened a manhole cover and dumped two bushels of a gelatinous substance into a pipe leading from the mine.

The sabotage was discovered yesterday morning before it could create a dangerous situation because of pressure building up in the abandoned deep mine, said the Mountain Watershed Association, the nonprofit organization that finished installing the Anna and Steve Gdosky Indian Creek Restoration Project last fall.

The substance pulled from the manhole by Fayette County hazardous materials workers and placed into a 55-gallon drum by the state Department of Environmental Protection was identified as ammonium chloride, which is sold in 5-gallon buckets by hardware stores and used to clean the tip of a soldering iron, in solder as flux and in snow making to slow melting.

Helen Humphreys, a DEP spokeswoman, said state police are investigating, but neither the treatment project nor the creek sustained any long-term damage.

Beverly Braverman, executive director of the Mountain Watershed Association, said the ammonium chloride partially blocked the pipeline running under Route 711 from the abandoned mine pool to the treatment ponds near the creek.

"Whoever did this is a total idiot because the project was done to reduce the risk of a blowout from the mine pool that could endanger people in the area, their homes and wipe out life in 12 miles of the creek all the way down to the Youghiogheny River," Ms. Braverman said.

She said the pool has risen about 5 feet inside the mine and could have created dangerous pressure on the hillside in the area if it had risen another 5 feet.

The 10-acre project treats what is known as the Kalp Discharge, responsible for more than 40 percent of the total mine pollution in the Indian Creek watershed. This discharge produces more than 184 million gallons of acidic mine water every year.

Before installation of the passive treatment project, which uses settling ponds and natural buffers to neutralize the mine water and settle out iron and other metals, the discharge carried about 76,800 pounds of iron into the creek each year and was long recognized as a health and safety problem.