Abstract: Disclosed is a method for dynamically constructing and updating a model of 3-dimensional topography of a stock-pile of granular material is provided. The method includes dumping the granular material to a maximum slope in a column in the stock-pile, wherein the maximum slope is determined by analyzing digital scans of the stock-pile; reducing the maximum slope to a smaller value of the maximum slope, dynamically increasing the maximum slope linearly until it reaches the original value of the maximum slope to obtain a uniformly expanding plateau; defining an adjustable shape comprising a first distance and a second distance, wherein the adjustable shape is flat till the first distance and the second distance beyond which the adjustable shape varies with the maximum slope; and reclaiming the granular material that flows downhill from a center depth to update the model of the 3D topography of the stock-pile.