Section 690-704 - Proof of rock cover(a) Requirement.--Proof of the existence of 35 feet of rock cover must accompany any plan submitted under this chapter.(b) Sufficiency.--Proof of rock cover is to be ascertained by testing holes drilled on:(1) intersecting lines forming rectangles or squares where the cover thickness is less than 50 feet; and(2) on spacing of not more than 35-foot centers.2008, July 7, P.L. 654, No. 55, §704, effective in 180 days [ 1/5/2009].