Flow pattern of granular ore rock in a single funnel under a flexible isolation layer

Due to the existence of a flexible isolation layer the flow pattern of granular ore rock in the synchronous filling shrinkage method breaks through the description range of the traditional ore drawing theory,so studies on the flow pattern of granular ore rock in a single funnel under a flexible isolation layer have important significance for enriching the ore drawing theory. Based on the similarity principle,a physical test model was designed,by which the morphology of the draw ore body and the loosen ore body was delineated and drawn by marking particles. The basic data of testing were recorded with a high-definition camera. The evolution laws of the spatial morphology of the draw ore body,loosen ore body,and cavity during single funnel drawing under a flexible isolation layer were analyzed on the basis of these basic data. The draw ore body showed completely closed and quasi-ellipsoidal morphology before the highest horizon ore settled; but after this settlement the draw ore body was gyrostatic. Before settlement of the highest horizon ore occurred,the loosen ore body showed completely closed and quasi-ellipsoid morphology; but after this settlement appeared,the loose body shape was trumpet-shaped on the whole,with an exponential curve in the upper part and a quasi-ellipsoid in the lower part. The cavity began to form at the moment when the settlement of the highest horizon ore occurred. The isolation layer was tangent to the ore layer at the cavity boundary. The cutting angle increased with the increasing fall depth of the isolation layer and kept invariant after it reached to the natural repose angle. With the sinkage of the isolation layer,the position of the tangent point gradually changed from the center to both sides until the end of ore drawing.