Saving costs on pumping the water to the surface wasnt the only reason the drainage tunnel was built. Evidently at the time prior to its construction the water was dumped into the public sewers.
Quote:
Annual report of the Commissioner of Health of the ..., Volume 4, Part 1
reported that the Pennsylvania Coal Company which operates all the washeries and mines in the borough, excepting the Green Ridge mine, is constructing a tunnel from the Lackawanna river through the northern part of Scranton and Dunmore borough for the purposes of obviating mine drainage pumping, substituting therefore this gravity tunnel. When this Improvement is completed, the drainage of the mines will be diverted from Roaring Brook and the Dunmore trunk sewer through the tunnel directly to the river. Probably the washeries will also be likewise drained.
And on a side note.( late 1800' early to mid 1900's) At the time the local rivers and streams were used as public sewers.And also as outlets for water pumped from the mines. Evidently the sulfur and other minerals in mine water had a disinfecting effect on the water. It was quoted in one book how lucky the communities are that the coal companies discharge there mine water, keeping the outbreak of various diseases at bay !!!!!!!!!!!!!