"We gave ourselves a little time to grieve," frontman Corey Taylor told the Herald at the time of its release.
"When you haven't been in that situation, you never know how it's going to affect you.
"We're very much a business-as-usual type of band, but we couldn't fight the depression, the grief. It kept clinging to us."
In the United States today, the band announced their own Knotfest event would be combining with Ozzfest as "Ozzfest Meets Knotfest" , a show which will be one of the final American shows by Ozzy Osbourne's Black Sabbath which recently played at Vector on the band's farewell tour.
The two-day mega event takes place in San Bernadino, California in late September, before Slipknot head to Australia and then New Zealand.
Tickets for Slipknot's Auckland show go on sale on Monday, May 23 at 11am.