Schaer said that burying several miles of Spruce Fork headwaters along Pigeonroost will not damage the quality or quantity of water downstream.
"Once discharge from the valley fills and the ponds reaches equilibrium, the inputs for surface and groundwater would be the same as prior to mining and, therefore, the discharge would be the same as prior to mining," Schaer said.
On cross-examination by Lovett, Schaer said he did not study the possible effects on water quality further downstream from the Hobet mine and numerous other mines in the area.
"To go on and examine the Little Coal or Coal rivers would be to discuss literally thousands of permits," Schaer said. "There's a point where I can't handle, as one human being, that much data."
Also Thursday, former A.T. Massey Coal executive Eugene Kitts testified on Arch Coal's behalf that mountaintop removal valley fills do not harm the environment.
Kitts, now a coal industry engineering consultant, said valley fills make streams flow more consistently and help hold back rainfall to avoid flooding.
"In my experience, based on my observations, a valley fill tends to act as a sponge," Kitts said.
"Water that falls due to rainfall onto the fill soaks into the fill," he said. "It's collected in the fill itself, gradually drops to the bottom, where it is eventually picked up by the under-drains and discharged," Kitts said.
"It makes the flow more even and steady," he said.