Let \( O \) be the origin and \( OP \) and \( OQ \) be the tangents to the circle \( x^{2} + y^{2} - 6x + 4y + 8 = 0 \) at the points \( P \) and \( Q \) on it. If the circumcircle of the triangle \( OPQ \) passes through the point \( \left(\alpha, \dfrac{1}{2}\right) \), then a value of \( \alpha \) is:
