Andrei MihaiIt’s a good time to be a metal fan: guitarist Jim Root of Slipknot and Stone Sour recently posted a photo to confirm the band’s studio entrance; previously, vocalist Corey Taylor said they will be starting work on a ‘very heavy album’. Featuring a heavily tattooed arm holding a Fender guitar by a mixing board, the photo on Instagram sends out a pretty clear message that new stuff is on the way; the comment is…