page_title: Portland stone
section_title: Mining
hierarchical_section_title: Portland stone / Quarries and mines / Mining
caption_attribution_description: English: Photograph taken by Mark A. Wilson (Department of Geology, The College of Wooster). [1]
context_page_description: Portland Stone or Portland Stone Formation is a limestone formation from the Tithonian stage of the Jurassic period quarried on the Isle of Portland, Dorset, England. The quarries are cut in beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles, notably in major public buildings in London such as St Paul's Cathedral and Buckingham Palace. Portland Stone is also exported to many countries—being used for example in the United Nations headquarters building in New York City.
context_section_description: Mining in Portland is done by using a room and pillar method. The mine is advanced by extracting the stone using an abrasive tool chain cutter mounted on a machine. Slots are cut into the top, bottom, sides and middle of the stone. A flat steel pillow is inserted into the middle cut and slowly inflated with water. The stones are gently broken off at the back without placing any stress on the resulting blocks. This method of extraction is significantly more expensive than blasting, but results in a higher yield thereby saving valuable reserves for future generations. The environmental benefits are substantial as mining significantly reduces the impact on wildlife and the local community with reduced noise and dust.
caption: Portland stone quarry on the Isle of Portland, Dorset.
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