a magnetic pump in a pump well in a molten metal furnace with a long , relatively thin side wall that wraps around a significant fraction of the circumference of the pump , which facilitates creation of an eddy current based flow field in the molten material with better magnetic coupling , thereby enhancing the effectiveness of the pump . breach of the well wall will not result in spillage of metal outside the furnace , and the well can be monitored for any such breach or other change so that the pump can be lifted out of the well to protect it from contact with the molten metal in the event of such a breach , or other appropriate action can be taken .