The above video shows one of the last controlled explosions that will ever take place beneath New York's Grand Central Station. The MTA, which governs New York's public transportation, is building two massive tunnels, 160 feet below street level, to house 8 tracks of Long Island Railroad.
To do that, you need to blow a lot of stuff up. Specifically, you need more than 2,4000 controlled blasts, which will require 1,000 employees working 24 hours a day, 5 days a week for nearly a month -- per the MTA's press release. In their words,
"To conduct a blast, teams of sandhogs drill hundreds of holes measuring 1½ inches in diameter into the mica-inflected granite schist that forms the bedrock of Midtown Manhattan. Together, the holes are loaded with 200 to 500 pounds of an explosive powder known as Emulex. After the sandhogs clear into a safe area, the Blaster-in-Charge issues a warning – “fire in the hole!” – and triggers the blast."
The blasting project under Grand Central Station was concluded today, April 9 2013.