Blasting of the 1,150-foot tunnel through solid rock for the outlet channel of the gigantic Bear Creek Reservoir is about half finished and should be through the mountain by the end of December. The tunnel is being constructed by Gasparini Excavating Company, Peckville, at a cost of $742,000. When completed, the concrete-lined tunnel with an inside diameter of 16 feet will be used for diversion of the Lehigh River while the mammoth 234-foot dirt and rock embankment is being built across the river valley and for reservoir operations after completion of the dam.