Editing Naval mine (section)

==== United States ====
[[File:9th Bombardment Group Aerial Mining.jpg|thumb|upright|A [[B-29 Superfortress]] dropping sea mines over Japanese home waters]]

As early as 1942, American mining experts such as Naval Ordnance Laboratory scientist Dr. Ellis A. Johnson, CDR USNR, suggested massive aerial mining operations against Japan's "outer zone" (Korea and northern China) as well as the "inner zone", their [[Japanese Archipelago|home islands]]. First, aerial mines would have to be developed further and manufactured in large numbers. Second, laying the mines would require a sizable air group. The [[US Army Air Forces]] had the carrying capacity but considered mining to be the navy's job. The US Navy lacked suitable aircraft. Johnson set about convincing General [[Curtis LeMay]] of the efficacy of heavy bombers laying aerial mines.<ref>{{cite book |title=Spying Without Spies: Origins of America's Secret Nuclear Surveillance System |last=Ziegler |first=Charles A. |year=1995 |publisher=Praeger |isbn=0-275-95049-2 |page=118 }}</ref>

[[B-24 Liberator]]s, [[PBY Catalina]]s and other bomber aircraft took part in localized mining operations in the [[South West Pacific theatre of World War II|Southwest Pacific]] and the [[China Burma India Theater of World War II|China Burma India (CBI)]] theaters, beginning with a successful attack on the [[Yangon River]] in February 1943. Aerial minelaying operations involved a coalition of British, Australian and American aircrews, with the RAF and the [[Royal Australian Air Force]] (RAAF) carrying out 60% of the sorties and the USAAF and US Navy covering 40%. Both British and American mines were used. Japanese merchant shipping suffered tremendous losses, while Japanese mine sweeping forces were spread too thin attending to far-flung ports and extensive coastlines. Admiral [[Thomas C. Kinkaid]], who directed nearly all RAAF mining operations in CBI, heartily endorsed aerial mining, writing in July 1944 that "aerial mining operations were of the order of 100 times as destructive to the enemy as an equal number of bombing missions against land targets."<ref name="Diane"/>

A single B-24 dropped three mines into [[Haiphong]] harbour in October 1943. One of those mines sank a Japanese freighter. Another B-24 dropped three more mines into the harbour in November, and a second freighter was sunk by a mine. The threat of the remaining mines prevented a convoy of ten ships from entering Haiphong, and six of those ships were sunk by attacks before they reached a safe harbour. The Japanese closed Haiphong to all steel-hulled ships for the remainder of the war after another small ship was sunk by one of the remaining mines, although they may not have realized no more than three mines remained.<ref name=G&B/>

Using [[Grumman TBF Avenger]] torpedo bombers, the US Navy mounted a direct aerial mining attack on enemy shipping in [[Palau]] on 30 March 1944 in concert with simultaneous conventional bombing and strafing attacks. The dropping of 78 mines deterred 32 Japanese ships from escaping [[Koror]] harbour, and 23 of those immobilized ships were sunk in a subsequent bombing raid.<ref name=G&B>{{cite journal |last1=Greer |first1=William L. |last2=Bartholomew |first2=James |year=1986 |title=The Psychology of Mine Warfare |journal=Proceedings |volume=112 |issue=2 |pages=58–62 |publisher=[[United States Naval Institute]] }}</ref> The combined operation sank or damaged 36 ships.<ref>{{cite web| url = http://www.nps.gov/pwrh/peleliu/appa.htm| title = National Park Service. ''Peleliu''. Appendices.| access-date = 24 May 2008| archive-date = 4 December 2008| archive-url = https://web.archive.org/web/20081204115706/http://www.nps.gov/pwrh/peleliu/appa.htm| url-status = live}}</ref> Two Avengers were lost, and their crews were recovered.<ref>{{cite book |title=The Development of Mine Warfare: A Most Murderous and Barbarous Conduct |last=Youngblood |first=Norman |year=2006 |publisher=Greenwood |isbn=0-275-98419-2 |page=138 }}</ref> The mines brought port usage to a halt for 20 days. Japanese mine sweeping was unsuccessful; and the Japanese abandoned Palau as a base<ref name="Diane">{{cite book |title=Mines Away!: The Significance of US Army Air Forces Minelaying in World War II |year=1992 |publisher=Diane}}</ref> when their first ship attempting to traverse the swept channel was damaged by a mine detonation.<ref name=G&B/>

In March 1945, [[Operation Starvation]] began in earnest, using 160 of LeMay's B-29 Superfortress bombers to attack Japan's inner zone. Almost half of the mines were the US-built Mark 25 model, carrying {{cvt|1250|lb|kg|order=flip}} of explosives and weighing about {{cvt|2000|lb|kg|order=flip|sigfig=1}}. Other mines used included the smaller {{cvt|1000|lb|kg|order=flip|sigfig=1}} Mark 26.<ref name="Diane"/> Fifteen B-29s were lost while 293 Japanese merchant ships were sunk or damaged.<ref>{{cite web |url=http://aupress.au.af.mil/Books/USSBS/USSBS.pdf |title=The United States Strategic Bombing Surveys (European War) (Pacific War) |archive-url=https://web.archive.org/web/20030825163637/http://aupress.au.af.mil/Books/USSBS/USSBS.pdf |archive-date=2003-08-25 |access-date=2011-12-31 |url-status=dead }}</ref> Twelve thousand aerial mines were laid, a significant barrier to Japan's access to outside resources. Prince [[Fumimaro Konoe]] said after the war that the aerial mining by B-29s had been "equally as effective as the B-29 attacks on Japanese industry at the closing stages of the war when all food supplies and critical material were prevented from reaching the Japanese home islands."<ref>{{cite book |title=The Development of Mine Warfare: A Most Murderous and Barbarous Conduct |last=Youngblood |first=Norman |year=2006 |publisher=Greenwood |isbn=0-275-98419-2 |page=139 }}</ref> The [[Strategic Bombing Survey (Pacific War)|United States Strategic Bombing Survey (Pacific War)]] concluded that it would have been more efficient to combine the United States's effective [[Pacific War#Submarine warfare|anti-shipping submarine effort]] with land- and carrier-based air power to strike harder against merchant shipping and begin a more extensive aerial mining campaign earlier in the war. Survey analysts projected that this would have starved Japan, forcing an earlier end to the war.<ref>{{cite web |url=http://www.anesi.com/ussbs01.htm |title=United States Strategic Bombing Survey, Summary Report (Pacific War). July 1, 1946 |publisher=Anesi.com |access-date=2013-07-07 |archive-date=16 May 2008 |archive-url=https://web.archive.org/web/20080516014539/http://www.anesi.com/ussbs01.htm |url-status=live }}</ref> After the war, Dr. Johnson looked at the Japan inner zone shipping results, comparing the total economic cost of submarine-delivered mines versus air-dropped mines and found that, though 1 in 12 submarine mines connected with the enemy as opposed to 1 in 21 for aircraft mines, the aerial mining operation was about ten times less expensive per enemy ton sunk.<ref>{{cite book |title=Mine Warfare at Sea |last=Levie |first=Howard S. |year=1992 |publisher=Springer |isbn=0-7923-1526-X |page=89 }}</ref>