Mining in the State Line Serpentine Barrens

Note: These pages are a work in progess. It is planned to add more details and photographs in the future.

The main mineral extracted from the Serpentine Barrens has been chromite, a chromium ore. Other minerals mined include feldspar, magnesite, soapstone, corundum, and talc. The serpentine rock has also been used for building. Local mines for building and road stone included the Dunlap, White Barrens, and the Carter, Reynolds & Griest quarries. It is still being mined for dimension stone at the Cedar Hill quarry, and is used for roads and other purposes.

In other serpentine areas, such as those in Maryland, Vermont, and Ontario, asbestos has been mined. The amounts of asbestos found in the State Line Serpentine Barrens are generally small and little or no commercial extraction has taken place.

The main period of mining took place during the 19th century. Historical maps are available for viewing. A database of newspaper clippings from the 1860s to the 1980s that can be browsed or searched has also been created.

Pages have been written for each of the more than 80 mines, quarries, and prospects. You can navigate to the these pages either through a list of mines ordered by the mineral extracted, or through a set of interactive maps. The information on these pages is mainly from Pearre & Heyl (see reference below) and newspaper clippings. It is planned to add more information sources in the future.

The developer of the chromite mining was Isaac Tyson (1792 - 1861), a Baltimore Quaker. See Tyson’s Wikipedia Biography, and his Mining Hall of Fame profile. The description of Tyson’s career is somewhat different in ‘The Fells Point Story’.

In 1826 he started purchasing properties in the State Line Serpentine Barrens in order to develop the chromite resources. Tyson made many land purchases, sales, and contractual agreements.Tables are available of his Chester County deeds, Lancaster County deeds, and Contractual Agreements.

Among later miners was Moro Phillips (1815 - 1885), a Polish immigrant who was a chemicals manufacturer in Philadelphia.

Most of the chromite deposits were located in hard rock but some placer deposits were also exploited, such as those at Black Run (Nottingham County Park), Pine Run, Goat Hill; Rock Springs; Little Elk Creek; and the Tweed Mine. The production of chromite sand has been estimated to have been over 10,000 tons.

The remains of Chromite mines can be seen at Nottingham County Park, Rock Springs, and Goat Hill. The Wood Mine, the most productive mine, which produced over 100,000 tons of ore, is on private land and the area is not open to the public. Exploratory diggings can also be found at New Texas and Chrome. The estimates of production amounts are very uncertain. By the 1870s most of the veins of chromite has been worked out. Some mines were re-opened during the World Wars in the 20th century.

Most of the chromite was used to manufacture chemical compounds, pigments, and dyes before the metallurgical and refractory uses of chromium, such as plating and alloying, were developed. In 1845 Tyson patented a process for manufacturing potassium bichromate, a pigment, and set up a smelting works at Fell’s Point in Baltimore. The Baltimore Chrome works continued operating until 1985.

The information about the mines and quarries is taken from Chromite and Other Mineral Deposits in Serpentine Rocks of the Piedmont Upland Maryland, Pennsylvania, and Delaware by N.C. Pearre and A.V. Heyl, Geological Survey Bulletin 1082-K, U.S. Department of the Interior, 1960, and other sources. More photographs and descriptions for some of the mines is found in The Mines and Minerals of Chester County, Pennsylvania by R.A. Sloto, self-published, 2009.