Slate mining is concentrated primarily in the Taconic Mountain region of southwestern Vermont known as Slate Valley. Other regions of Vermont have produced slate, such as the eastern Connecticut River valley and central portions of Vermont spanning from Newport to Barnard, but not of the quality that is produced in Slate Valley (Offensend, 2003). The first quarrying and manufacturing of slate began in 1839 in Fair Haven. Slate production in Fair Haven and the nearby towns of Castleton, Pawlet, Wells, and Poultney reached its climax between 1850 and the early 1900s (United States Department of Interior, Bureau of Mines, 1980). This period also saw an influx of Welsh immigrants who were knowledgeable about slate mining. They emigrated from North Wales, a region dependent on slate quarries, and brought with them Welsh traditions, such as song and religion, as well as skilled labor. The immigrants have since been assimilated in the Slate Valley but their impact, culturally and economically, can still be felt today in the towns and quarries of southwestern Vermont (Roberts, 1998; Carpenter, 2002).
In the past, slate was quarried by hand tools, including hammers and chisels, from small surface quarries. The Welsh brought with them derrick mechanisms for lifting the stone out of quarries as well as punchers and trimmers, both of which were used in the finishing process for roofing slate. Today, high speed diamond-plated saws and laser levels help make precise cuts and reduce waste, though not all slate mining practices have advanced; explosives are still used in the initial quarrying process to break the stone apart. The Slate Valley is renowned for producing green, gray, black, red (though this is found primarily in east-central New York), and mottled (mixed coloration) slate. These colors were formed as a result of varying cooling temperatures and chemical reactions during the metamorphism of shale. It is estimated that slate formed between 450 and 650 million years ago, during the Paleozoic Era. This transition from shale to slate is responsible for a sturdy and strong stone that can be broken into flat continuous pieces. Thus, it is currently used for blackboards, roofing, flooring, mantels, tabletops, and even monuments, headstones, and memorials.
Slate quarries have impacted not only the economy and culture of Vermont towns, but it has also damaged and degraded their landscape. In order to mine high quality slate, trees need to be removed and quarries need to be created. The result is a permanent scaring of the landscape as well as an increase in noise pollution, air pollution, and soil erosion. Another environmental problem is waste. Even though few chemicals are used in the mining process, roughly 90% to 95% of the materials removed are considered slag, or waste. In the case of old and abandoned mines, waste is often left behind, further altering the landscape. However, slate slag is not as harmful as copper or calcium carbonate (marble composite) waste, and many operational slate mines export their waste to nearby states such as New York and New Jersey. Recent disputes have centered around blasting noise and associated damage, as well as water pollution. Since water is often used to help split slate, run-off into nearby waterways or local water supplies is a concern. These disputes are often resolved through lawsuits since Vermont’s Act 250 (land use and development law) does not apply to the slate industry. Accordingly, little remediation or clean-up of the state’s many small slate mines is done because they are either abandoned or would require substantial change. State and federal authorities regulate the slate industry’s employees through Mine Safety and Health Administration (MSHA of the Department of Labor) and the Vermont Occupational Safety and Health Administration, but they are not responsible for enforcing environmental laws and regulations.
Today, small scale operations continue to dot the landscape, particularly in Rutland County. According to the Vermont Geological Survey’s Mine Reference File, in August of 2003 there were 15 intermittent and 23 full time quarries that employed a total of 348 people; there were also 16 abandoned slate quarries.
Carpenter, S. 2002. A Study in Slate: Welsh Immigration: Its Effects on the Slate Valley (1840-1870), the Slate Industry from 1901-1930, and Environmental Impacts of Slate Quarrie. Undergraduate thesis, University of Vermont.
Offensend, D. 2003. The Western Vermont Slate Belt: Fair Haven. Rutland, VT: Academy Books.
Roberts, G. R. 1998. New Lives in the Valley: Slate Quarries and Quarry Villages in North Wales, New York, and Vermont, 1850-1920. Somersworth, NH: New Hampshire Printers.
United States Department of Interior, Bureau of Mines. 1980. Study of the Slate Mining Industry of Vermont/New York: Final Report. Cambridge, MA: Arthur D. Little, Inc.