For upstream tailings pond with permeable rock-fill starter dam, slope swamping of tailings-fill dam is often found in later stage due to high water level, short dry beach, inadequate tailings permeability, steep slope, or absence of seepage facilities. We have rich experiences in the treatment of such slope swamping, but researches and treatment measures on the swamping of earth-rock starter dam are rare. Through analyzing the causes of starter dam swamping and comparing the treatment measures, we applied horizontal seepage draining pipes to the treatment. By observation and on-site investigation, we found that the depth of saturation line of earth-rock starter dam gradually declined, slope swamping diminished, and the dam’s stability improved. Through the experience we conclude that horizontal seepage draining pipes could eliminate the swamping of earth-rock starter dam.