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The coordinates take you to the Crimora Lake Overlook on the Skyline Drive in Shenandoah National Park. This overlook has a view ranging from Turk Mountain on the left to Wildcat Ridge on the right. Near the center of the view is Crimora Lake with its dark-colored water. To the left of Crimora Lake is a body of pale greenish water. This is a flooded, abandoned, open-pit manganese mine known as Crimora Mine. This mine last operated in 1959 and remains the largest source of manganese ever mined in the United States. This overlook is one of the best places to see the mine’s remains, which are outside of the boundaries of Shenandoah National Park. Manganese is a hard, grayish-white, brittle metal with the chemical symbol Mn. Manganese ranks thirteenth in abundance among the elements in the earth’s crust. Although it is found in over one hundred minerals, only a few are important sources. These sources include pyrolusite, psilomelane, manganite and brounite. The Crimora deposit consists of clay with scattered lumps of manganese ore. It lies under a layer of clay and quartz fragments about 15 feet thick, which forms the mounds you see from the overlook near the pale green body of water. The main use of manganese is in the manufacture of steel, where it has historically been used for eliminating oxygen and sulfur in the manufacturing process, and for adding carbon to finished steel. Also, when the manganese content of steel is increased from the normal amount found in steel - less than 1 percent - to between 11 and 14 percent, the steel becomes much tougher and resistant to abrasion. In steel rails, manganese increases the life of ordinary carbon steel 5 to 6 times. Manganese deposits in the United States are widely scattered through the Appalachian and Piedmont regions, the southern Mississippi Valley, and the Pacific coast. Although deposits of manganese are found on the East Coast from Vermont to Alabama, mining of manganese was most prevalent in Virginia and Georgia. The western edge of the Blue Ridge from Front Royal to Roanoke contains irregularly distributed deposits. Manganese ore occurs in pockets in clays of residual or sedimentary character, adjoining quartzite from the Lower Cambrian era. The Crimora Mine was the largest producer of manganese in the United States. Virginia supplied a large part of domestic production in the 19th century because it possessed a larger number of deposits than adjacent states and the mines were located closer to the steel production areas around Pittsburgh than mines in Georgia and Arkansas. Between 1880 and 1914, Virginia supplied 61 percent of domestic production, and nearly two-thirds of this ore is said to come from the Crimora Mine. About 42 percent of all production of manganese in Virginia has come from this mine. The Crimora Mine operated beginning in 1867 and continued off and on until 1959. The mine’s maximum period of production occurred from 1862 to 1892 when 130,000 tons of ore were shipped from extensive underground workings from shafts. By 1908, the Crimora mine had produced more manganese ore than all other mines in the United States combined, but competition from the cheaper supplies from Russia, India and Brazil made business unprofitable. Although domestic production of manganese ores almost equaled imports in 1890, it dropped precipitously to only 1 percent of imports during the five year period of 1910 to 1914. The Crimora Mine operated sporadically after the early 1900’s. It continued into the 1950’s only because the Korean War spurred Congress to subsidize manganese production in the United States, to guarantee a supply. This subsidy ended in 1959 when the desired amount of manganese had been stockpiled. The U.S. Government no longer stockpiles manganese ore, the last of which was sold in 2008. Now all manganese ore containing more than 20% manganese that is consumed in the United States is imported from other countries, principally from Gabon, South Africa, Australia and Brazil (in order of quantity during the years 2006-2009). In order to log a find, (1) email me the answers to the four questions listed below, and (2) optionally post a picture of you and your party from the Crimora Lake Overlook, showing your GPS, with your "found" log. The email should state the name of this Earthcache in the first line and include your profile name. Then you may log the find; I will let you know if anything needs correcting. 1. Why was manganese mined and what made the Crimora mine important? 2. Why did the Crimora mine close down? 3. How many small lakes make up the former Crimora mine? Estimate their size. 4. The Crimora manganese deposit consists of clay with scattered lumps of manganese ore. It lies under a layer of clay and quartz fragments about 15 feet thick, which forms mounds near the water that now covers the mine. Do you notice a different color or colors to these mounds? What color or colors do you notice? Special thanks to National Park Service and USGS staff members for their help with the accuracy of statements in this earthcache! Links and Resources: Manganese (Wikipedia) http://en.wikipedia.org/wiki/Manganese Crimora, Virginia (Wikipedia): http://en.wikipedia.org/wiki/Crimora,_Virginia “Some Manganese Mines in Virginia and Maryland,” by D.F. Hewett, Bulletin - United States Geological Survey, Issue 640 By Geological Survey (U.S.), 1917, p. 37. http://books.google.com/books?id=w1kMAAAAYAAJ&pg=PA37&dq=%22manganese+mining%22+crimora&hl=en&ei=HnN1TLH_NIKB8gac35GZBw&sa=X&oi=book_result&ct=result&resnum=8&ved=0CFQQ6AEwBw#v=onepage&q=%22manganese%20mining%22%20crimora&f=false Annual Report on the Mineral Production of Virginia during the Calendar Year 1908, Virginia Geological Survey. http://books.google.com/books?id=dHhGAAAAYAAJ&pg=PA35&dq=%22manganese+mining%22+crimora&hl=en&ei=iHh1TKT-McP58AabysCcBw&sa=X&oi=book_result&ct=result&resnum=2&ved=0CC8Q6AEwATge#v=onepage&q=%22manganese%20mining%22%20crimora&f=false The USGS National Minerals Information Center. http://minerals.usgs.gov/minerals/pubs/commodity/manganese/ The International Manganese Institute. http://www.manganese.org/
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