Room and Pillar

Room and Pillar. Natural Cement Mining. , You are standing in front of one of the many room-and-pillar Natural Cement mines, remnants of one of America's greatest home-grown industries. Rosendale Natural Cement was produced from a form of limestone, containing all the chemical components necessary to create Natural Cement., The extraction process largely involved the drilling of blasting holes and the setting of black powder and dynamite charges to dislodge large chunks of rock., The miners removed two layers of dolostone and left behind large open rooms with pillars to support the ceiling; hence the name "room-and-pillar mining." In the image to the left you see miners posing for a photograph in a room-and-pillar mine; note the foreman in a dark suit in the foreground., Once extracted, the rock was broken down into smaller pieces and transported to the large kilns nearby to be baked, a process known as calcination, which converted the natural rock into cement. The 3D diagram below shows a cross-section of the local geology and identifies the two "members" of dolostone that were extracted for Rosendale Cement., Many of the massive stone kiln structures are still intact on this property and throughout Rosendale., Rosendale Natural Cement had natural hydraulic properties, meaning it would harden under water, making it ideal for bridge, dam and canal construction., At the peak of production in the later part of the 19th century, the combined output of all the cement companies operating in the Rosendale area was in excess of 3.5 million barrels annually, representing more than 50% of all natural cement manufactured in the US at the time. Rosendale Natural Cement helped build the infrastructure of the United States, as well as many of our most famous landmarks such as the Brooklyn Bridge and and the base of the Statue of Liberty