After World War II, it was believed that the days of mine warfare were over, a conclusion that proved to be premature. Their usage again became apparent during both the Korean and Vietnam wars.

Mines in the Korean War

The North Koreans mined Wonson Harbor. The minefield consisted of 3,000 Russian mines, which included new ground mines, as well as moored mines of 1904 vintage. As in the past, mines proved to be very effective weapons.

Mine warfare in the Korean War was a shock to the U.S. Navy. As a result of the lesson learned in Korea, the Navy followed a more balanced approach to mine warfare in the 1950s. The development of the Mk 50 series influence mines with modular features provided the Navy with the 1,000-pound Mk 52 and 2,000-pound Mk 55 aircraft-laid bottom mines. These mines were sensitive to three influences of six variations. In the early and middle 1960s, two magnetic-influence moored mines became operational: (1) the aircraft-laid Mk 56, made of stainless steel; and (2) the submarine-laid Mk 57, made of fiber glass.

Mines in the Vietnam War

Mine warfare was next used in the war with North Vietnam, when the United States planted more mines than it did in all previous conflicts combined. Most of the mines used in Vietnam were modified versions of the low-drag aircraft bomb of the Mk 80 series. The modification was the result of the efforts of Gene Beach and Charles Rowsee at the White Oak Laboratory in Maryland, where the Mk 75 destructor adaption kit was developed. The kit permitted the conversion of the Mk 80 series bombs into magnetic mines known as destructors. The destructors could be used both on land and in the water. Ease in assembly permitted the use of over 250,000 of the destructors during the Vietnam War.

The destructors and other mines were used effectively in the mining of Haiphong Harbor and other North Vietnam ports. The mining operations were designed to prevent ships from leaving and entering the harbor and ports. Mining of Haiphong Harbor was accomplished with approximately 100 Mk 52 mines and 11,000 destructor mines. The operation was successful and, once again, highlighted mine usage in warfare.