A dipper assembly for a mining shovel includes a dipper body, a dipper door pivotably coupled to the dipper body, an arm, a housing coupled to one of the body and the door, and a piston. The arm includes a first end pivotably coupled to the body and a second end pivotably coupled to the door. The movement of the door relative to the body drives the arm to pivot relative to the body. The housing includes an inlet in fluid communication with a fluid source, an outlet, and a cylinder partially defining a pump chamber in fluid communication with the inlet and the outlet. The piston is movable within the cylinder and biased in a first direction. The pivoting movement of the arm causes the piston to move in a second direction opposite the first direction. The movement of the piston changes a volume of the pump chamber.