The significance of a massive sandstone unit in the immediate roof to longwall support weighting is well known. If the unit lies in the main roof above the zone of caving, its influence becomes more difficult to calculate using traditional methods. Much of the reserves at Cyprus Plateau's new multi-seam Willow Creek Mine are located in the A Seam in the main roof and is on average 14.6m thick, ranging to 29m thick. The paper describes the application of distinct - element modeling to determination of the appropriate yield capacity for supports at Willow Creek. The modeling was determined to be useful for understanding support loading mechanisms and as an aid to engineering judgment in selectiong supports.