A method for automated unloading of items from a container includes moving a nose ramp of an unloader under a base belt, which is positioned over a floor of the container. A stack of items are located in the container over the base belt. The method includes removing items from a bottom of the stack of items via an extraction conveyor of the unloader. The method also includes measuring a density of items transitioning onto the extraction conveyor from the base belt. The method further includes controlling an unloader advance speed relative to the container in dependence of the measured density of items transitioning onto the extraction conveyor. Thereby, a bulk flow of items having a substantially steady density is delivered by an output conveyor of the unloader positioned downstream of the extraction conveyor.