Land mines, equipped with pressure sensors slightly above or below ground, came into wide use in World War II, particularly in N Africa and Russia and on the Western front. They are of two general types—antipersonnel and antitank; the latter are designed so that lighter objects will not cause them to explode. Mines can now be manufactured to contain an internal clock that deactivates them after a set time period; they are referred to as "smart" mines. Mines whose detonation deactivation is not set are called "dumb" or persistent mines. To prevent magnetic detection, modern land mines have often been encased in plastic rather than metal.
No completely safe way of removing land mines is known. In World War II the United States and Great Britain developed several types of mine-detecting and mine-exploding equipment, but they proved inadequate. Despite technological advances, identification still usually requires an inch by inch probbing of the ground, which carries great risk and cost.
According to UN figures there are approximately 100 million mines laid across the world, with more than twice that amount in stockpiles. Angola is estimated to have 15 million mines; Cambodia, 10 million (which translates to one per citizen); Afghanistan, 10 million; and Bosnia and Croatia, 3 million each. It is most often the world's civilian populations that are injured (20,000 annually) or killed (10,000).
In 1997 an international treaty called for signatory nations to end the use, development, acquisition, and stockpiling of land mines and to destroy their current stocks of such mines; the treaty went into effect in 1999. More than 150 nations are now parties to the treaty. The United States has refused to sign the treaty, arguing that doing so would hinder the country's ability to protect its troops; Russia and China also have not signed. The International Campaign to Ban Landmines, a coalition of nongovernmental organizations, won the 1997 Nobel Peace Prize for its efforts to bring about the signing of the treaty. In 2004 the U.S. government announced that it would end the use of persistent land mines by 2010 (and before then outside the Korean peninsula).
Naval mines of various types have been used periodically since the 16th cent., but it was not until World War I that they entered into wide use. Modern naval mines, equipped with sonar or magnetic sensors, are laid on the surface of the sea or sometimes anchored below. They fall within two broad classifications—automatic and controlled. The automatic mine, once planted and armed, is activated by the presence of a ship; it is incapable of discriminating between friendly and enemy ships. The controlled mine, in contrast, is connected by electric cable to a shore station and can be disarmed to allow the passage of friendly vessels. For defensive purposes, mines are often placed in secretly charted locations near protected harbors by specially equipped vessels known as minelayers. As an offensive weapon, mines are placed in or near enemy harbors, generally by aircraft or submarine.
Minesweepers are employed as a countermeasure, often with wooden hulls to avoid magnetic mines. Helicopters can explode mines by towing sweeping equipment while traveling at a safe distance above the water. Minesweeping is vital both during and after a conflict, as thousands of active mines may still be floating in shipping lanes. As recently as the mid-1990s naval mines were discovered in the seabed off a popular beach in Malta; they had been laid by the British during World War II to sink German vessels.
U.S. labour union. Founded in 1890, the UMWA grew rapidly under the leadership of John Mitchell (president 1898–1908) despite determined opposition from coal-mine operators. By 1920, when John L. Lewis took over, the union had half a million members. Lewis capitalized on the pro-labour climate of the New Deal and led numerous strikes to win fair pay, safe working conditions, and benefits. The UMWA was a mainstay of the Congress of Industrial Organizations (see AFL-CIO) in its early years, but Lewis withdrew the union from the CIO in 1942. Unaffiliated for decades, the UMWA finally joined the AFL-CIO in 1989. The UMWA's importance declined in the later 20th century with the waning of the labour movement and the rise of alternative sources of fuel, and by the 1990s it had fewer than 200,000 members.
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Mine can also refer to: