On November 29, 1847, Isaac Hopper notes that William Morrell was employed by Sing Sing after his release to help build "Lime Kilns." According to the National Park Service, lime kilns are a special kiln used to "produce quicklime out of the calcination of limestone (calcium carbonate)." Quicklime, in turn, was used to make "plaster and mortar for building construction." The use of limestone dates back 14,000 years, but the Romans were the first to mix it with other ingredients for what is now cement's earliest ancestor. 

According to the Documents of the Assembly of the State of New York, Sing Sing used its lime kilns for more than on-site construction. It also sold quicklime cheaply (due to the exploitation of prisoner labor) to the outside world, which angered free-market producers. On September 24, 1870, T. Cromwell testified that "the lime manufactured from my quarry came into competition with the lime manufactured, as I am informed, by the State at Sing Sing. Since then, the business, by reason of the reduction in the price of lime made at Sing Sing, has been almost worthless."

Sources:

https://www.nps.gov/sagu/learn/historyculture/upload/Lime-Kilns-Brief.p…

Documents of the Assembly of the State of New York, Volume 2