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Rose Red Quarry Pillar Design <br /> Maximum Span between Pillars, <br /> Equations Utilized <br /> Force from Rock to Support = W = 6 X X2 X H <br /> Ability of Pillar to Support = S = cs x pZ/SF <br /> Vertical Forces Must be the Same = W = S <br /> W = S = a X X 2 x H= cs x p 2/SF <br /> Span of Suportable Rock x <br /> X = ((cs x p2)/(SF x a- x H))o.s <br /> Opening Span Between Pillars = OS = x — p <br /> Where: cs is the Compressive Strength of Granite (19,000 Ibs/sq in.) <br /> a- is the Density of Granite (167.9 Lbs/cubic foot) <br /> SF is a Safety Factor of 4.0 (recommended by NOSH) <br /> H is the Distance from the Roof of the Opening to the Surface (in feet) <br /> S is the Pillar Support Strength (Ibs/square foot) <br /> P is the Pillar Width on a side (feet) <br />