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Granite Quarrying in Maine
The quarrying of granite in Maine has been a commercial undertaking since the early 1800's. Prior to the opening of commercial quarries, granite was used primarily for building foundations, road, bridge and pier construction. Although quarrying peaked in Maine around 1901, activity in Maine's granite quarries continues to this day. At the height of the industry, granite was used as a building stone in locations all over the eastern United States (see Lepage and others, 1991). Today, what remains of the business is mostly involved in the building trades, kitchen design, and landscaping.
Notable buildings all over the United States were built with Maine granite from the mid-1800's to 1910 as Maine led the country in the mining of granite. Many public buildings such as libraries, churches, custom houses, post offices, and museums were built of Maine granite. One of the most famous is the Church of Saint John the Divine in New York City, with its huge sanctuary columns made from Vinalhaven granite.
What is granite?
Granite forms as molten rock (called magma) deep within the earth. When magma solidifies within the earth the resulting rocks are called intrusive or plutonic rocks. The grain size of the granite is determined by how fast or slow the molten rock solidifies. Fast-cooling magma forms small crystals, while slow-cooling magma forms large crystals. The erosion and uplift of the overlying rock exposes these plutonic rocks to the atmosphere.
The emplacement of many of the granite plutons in Maine took place hundreds of millions of years ago during the Silurian and Early Devonian time periods (440-390 million years ago) (see Osberg and others, 1985). Collisions of the plates that make up the crust of the Earth are ultimately responsible for generating the molten magma that cooled within the crust to form granite. Subsequent erosion exposed the granitic rocks at the surface of the earth.
C. T. Jackson published the first geologic survey of the state of Maine in 1837. He inventoried Maine's economic deposits, including some of Maine's granite quarries, and concluded that Maine would be able to support an active mining industry. The granite industry was already firmly established in the Penobscot Bay, eastern Washington County, Hallowell, Biddeford, and Blue Hill areas when Jackson published his report. By the late 1800's the industry was thriving along mid-coast Maine and on some of the offshore islands. Vinalhaven was a center of quarrying activity. Skilled laborers emigrated to the United States from Europe to work in the quarries.
The introduction of reinforced concrete spelled the doom of Maine's granite industry in the early 1900's. The introduction of union labor was also cited as one of the causes of the decline of the industry. Business costs could not keep up with locally quarried stone and the newly introduced reinforced concrete.
Today only a handful of quarries operate in Maine. These mines mostly work to supply stone to the housing market for countertops and landscaping purposes. Maine granite is still used in the building trades for facade.
Granite was quarried using steam drills, wedges and hammers. Steam drills (modern quarries use jet drills) drilled holes along the hard edge of the granite, perpendicular to the grain of the rock (see Figure 4). Along the grain of the rock (easy direction of splitting) wedges with feathers were used to easily break off the slabs (Figure 5). Derricks (Figure 6) were used to move the blocks up out of the quarry onto horse drawn wagons called galamanders (Figure 1). Modern quarries use power equipment to handle many of the tasks.
Dale, T. N., 1907, The Granites of Maine: U. S. Geological Survey, Bulletin 313, 201 p.
Jackson, C. T., 1837, First report on the geology of the State of Maine: Smith and Robinson, Augusta, 128 p.
Lepage, C. A., Foley, M. E., and Thompson, W. B., 1991, Mining in Maine: Past, present, and future: Maine Geological Survey, Open-File Report 91-7, 9 p.
Ludman, A., and Coch, N. K., 1982, Physical Geology: McGraw-Hill, New York.
Osberg, P. H., Hussey, A. M., II, and Boone, G. M., 1985, Bedrock Geologic Map of Maine: Maine Geological Survey, scale 1:500,000.
Rand, J. R., 1958, Maine granite quarries and prospects: Maine Geological Survey, Mineral Resources Index No. 2, 50 p. 1 map.
Text and photos by Robert Johnston.
Originally published on the web as the August 2003 Site of the Month.
Last updated on April 23, 2012
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