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Ruggles Mine

Ruggles Mine
Off Route 4 at the Village Green


The mountains and valleys of New Hampshire are rich with mineral formations. From the southwest corner of the state near Keene to the northern Canadian border near Littleton there are fascinating deposits of a variety of minerals. One of these deposits is known as the Littleton Formation which was formed during the Devonian era approximately 300,000,000 years ago. The mining of these mineral deposits has been an important part of New Hampshire history from prehistoric eras to the present. The Ruggles Mine, in Grafton N.H., is part of the Littleton Formation and has a rich mining and geological history. It is the oldest and largest mine of its kind in the United States. Minerals such as Mica, Feldspar, Beryl, and Uranium were mined at Ruggles for 175 years.

Minerals and rocks fall into three classes of identification, metamorphic, igneous, and sedimentary. All of these mineral formations are found in New Hampshire. Metamorphic rock is formed under extreme conditions of heat and pressure. Igneous rock is formed when magma or molten rock cools and solidifies. Sedimentary rock is formed when wind or water deposit sediments and the sediments become compacted. Sedimentary and igneous rock can become metamorphic under certain conditions of intense heat and pressure in the crust of the earth. Metamorphic rock can also change into another type of metamorphic rock. Heat and pressure do not change the chemical makeup of parent rocks but they do change the mineral and physical properties of those rocks.

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