During the 28-mi. (45 km) refurbishment of Interstate 99 in Centre County, which began in 2000, road crews discovered a major problem: rock laced with pyrite.
The Pennsylvania Department of Transportation (PennDOT) applied for permits on Jan. 31 to remove acid rock, or pyrite, from sections of Interstate 99 in Centre County. PennDOT, as well as Robindale Energy Services, submitted applications with the Department of Environmental Protection (DEP) for the work.
One of the permit applications addressed PennDOT’s plan to complete work on two areas with the acid rock, where the northbound and southbound lanes are on different elevations — also known as Buttress/Bifurcation areas. The other permit application addressed PennDOT’s plan to remove and transport approximately 650,000 cu. yds. (496,961 cu m) of pyritic material to a facility that would be constructed at a Robindale-owned mine site in Indiana County.
“Eliminating this problem is our goal and applying for these permits is an important first step to reaching a final resolution,” said Kevin Kline, PennDOT’s district executive for the region “We look forward to working with Robindale Energy Services and DEP to develop an effective plan. We believe our proposal offers a sound way to clean up the acid rock and allow us to finish the I-99 project.”
However, overwhelming public concern has brought the process to a halt. On March 2, the governor’s office published a press release announcing a postponement in plans to dispose of pyrite from sections of Interstate 99 in Centre County. Pennsylvania Secretary of Transportation Allen D. Biehler, P.E., said PennDOT will immediately re-examine its plans for the disposal of the pyrite-laden sandstone.
“There has been significant concern raised by the public and local officials about plans to transport this pyrite from the site in Centre County to a disposal site in Pine Township, Indiana County,” Biehler said. “While there is no danger or health hazard to the public in transporting this material to a site, I have directed a halt to any of those plans while we begin an immediate evaluation of all options for disposal of this material.
“I have been meeting with the Pennsylvania Department of Environmental Protection and Secretary Kathleen McGinty to discuss all options available to us,” Secretary Biehler added. “Our two agencies will continue to work together in this effort as we analyze and study all options for the disposal of the pyrite from the Interstate 99 project.
Robindale’s proposed contract with PennDOT for removal and hauling is $26 million. Covering up the 400,000 cu. yds. (305,822 cu m) that will remain on Skytop Ridge will cost an additional $14 million, according to the Pittsburgh Post-Gazette.
This is in addition to the $10 million that has already been spent on pyrite remediation, and the original $40 million spent on I-99 construction for the 1.3 mi. (2.1 km) affected by the pyritic rock. PennDOT is left with a $750-million price tag for the reconstruction of I-99.
Since 2003, PennDOT has overseen interim remediation efforts in the area. Acid rock drainage can be caused when unearthed pyritic rock is exposed to air and precipitation. The sulfuric acid can contaminate nearby groundwater that runs to trout streams and residential drinking wells.
“We originally planned to layer the pyrite with lime. However, we didn’t anticipate the concentration being so intense that the lime would not offset the reaction once the rock was exposed to air and water,” said Marla Fannin, press officer of PennDOT District 2.
Under the current plan-on-hold, the rock that is hauled out of the 1.3 mi. would be mixed with fly ash on a 1 to 1 ratio at the Robindale mine which will neutralize the sulfuric acid.
Some of the pyritic rock will have to stay at the Skytop Ridge site, either on a rock face or to help support the highway. To shield that rock from oxygen and water, the areas will be covered with three layers of impermeable plastic, as well as lime-kiln dust and synthetic webbing, reports the Post-Gazette.
“There were two main concerns voiced by the people of Indiana and Cambria counties. The first issue was the safety of hauling the material. Residents are concerned with the volume of traffic on the proposed route from the I-99 pyrite rock site to the Robindale mine; a 74-mi. stretch. One possible route crossed over a one-lane bridge in Dilltown on SR 403 south of SR 422,” Fannin said.
“The other main issue was the public misconception that pyrite rock is a hazardous material. PennDOT addressed this concern by explaining what the material is and why it needs to be moved,” Fannin continued.
The Department of Environmental Protection also cancelled two public meetings and hearings that were to be held on March 7 in Indiana County and March 9 in Centre County in which the residents would have had the opportunity to ask questions and present testimony regarding permit applications submitted by Robindale Energy Services and the Pennsylvania Department of Transportation to correct the Interstate 99 acid rock drainage problem in the Skytop area of Centre County.
“Our first concern remains protecting the public and making sure we appropriately consider each alternative and the impact it will have on our communities. We want to do this in the least disruptive and most effective manner,” Secretary Biehler said.
Fannin said that PennDOT is now in the review stage with the DEP for other solutions to the pyrite rock removal. Part of the review will examine ways that the rock could be re-routed to Robindale. PennDOT will present the final remediation options at a public meeting to be held on April 10th at 7 p.m. at Park Forrest Middle School in Patton Township, Centre County.
“Our agencies remain committed to working together to find an effective solution that will address disposal and containment of the pyretic rock,” Biehler said. CEG