If you've driven into the countryside surrounding Pittsburgh recently, you may have seen few skyscraping rigs like this one. They're popping up across Pennsylvania as drillers tap the Marcellus Shale rock formation to access lucrative natural gas. These panoramics are the most comprehensive tour of a rig site yet recorded. Stage one is the drilling process, in which companies puncture the earth and reach depths of around 6,000 feet -- the length of 20 football fields. Once drilling starts, the rig operates 24 hours a day, seven days a week for three to four weeks.
(Panorama by Steve Mellon / Posted Monday, Oct. 17, 2011)
Click on the links below to see earlier panoramics.