A method of storing and moving proppant, the method comprising: a) stacking a plurality of containers that each contain proppant within an interior volume structurally strengthened to receive the proppant on top of one another so that a bottom of one of the plurality of containers overlies the top of another one of the plurality of containers to thereby define a stack, the stack reducing the footprint of the plurality of containers, the structural integrity of the plurality of containers enhanced by supporting members including a plurality of structural uprights (44, 46) positioned on respective end surfaces of the plurality of containers and extending from the bottom to the top of each of the plurality of containers and thereby increase the weight carrying capacity of each of the plurality of containers so that a large amount of weight can be stacked upon the container and so that heavy weight can be stored therein, the plurality of containers each includes an inner surface shaped to funnel the proppant toward an outlet, a flow gate positioned adjacent the outlet to control flow of proppant through the outlet and moveable between a closed position to retain proppant in the interior volume and an open position to allow proppant to flow therefrom along the inner surface and through the outlet; b) placing one or more of the plurality of containers from the stack onto one or more of a plurality of trailers of associated trucks by use of a container loader/unloader; and c) moving the plurality of containers when positioned on the plurality of trailers of associated trucks away from the stack of the plurality of containers; wherein each of the plurality of containers includes the outlet adjacent the bottom for discharge of proppant therefrom, an opening adjacent the top thereof to load proppant therein, a pair of spaced-apart end walls (22, 24) connected to and extending between the bottom and the top, and a pair of side walls (18, 20) connected to and extending between the pair of end walls (22, 24) and the top and the bottom, and wherein each of the plurality of containers further includes one or more other supporting members rigidly extending between and rigidly affixed to the pair of end walls (22, 24) and one or more other supporting members (38, 40) rigidly extending between and rigidly affixed to the pair of side walls (18, 20). a) stacking a plurality of containers that each contain proppant within an interior volume structurally strengthened to receive the proppant on top of one another so that a bottom of one of the plurality of containers overlies the top of another one of the plurality of containers to thereby define a stack, the stack reducing the footprint of the plurality of containers, the structural integrity of the plurality of containers enhanced by supporting members including a plurality of structural uprights (44, 46) positioned on respective end surfaces of the plurality of containers and extending from the bottom to the top of each of the plurality of containers and thereby increase the weight carrying capacity of each of the plurality of containers so that a large amount of weight can be stacked upon the container and so that heavy weight can be stored therein, the plurality of containers each includes an inner surface shaped to funnel the proppant toward an outlet, a flow gate positioned adjacent the outlet to control flow of proppant through the outlet and moveable between a closed position to retain proppant in the interior volume and an open position to allow proppant to flow therefrom along the inner surface and through the outlet; b) placing one or more of the plurality of containers from the stack onto one or more of a plurality of trailers of associated trucks by use of a container loader/unloader; and c) moving the plurality of containers when positioned on the plurality of trailers of associated trucks away from the stack of the plurality of containers;