The Evraz Group, Russia's largest steel and mining company, announced the completion of a deal to sell the remaining 49% in NS Group to TMK for $508 million.

"The proceeds from the sale will be kept in reserve against future interest payments on the company's debt in 2009," Evraz said in a news release.

TMK, Russia's largest steel pipe manufacturer, exercised its right under a put/call option agreement for 49% of NS Group that the company signed with Evraz last year.

In March 2008, Evraz entered into an agreement with SSAB, a Swedish steel company, to acquire IPSCO's Canadian and U.S. businesses, while simultaneously entering into a back-to-back agreement with TMK.

The back-to-back transaction consisted of a sale of the acquired U.S. tubular and pipe businesses, including 51% in the NS Group, to TMK for $1.25 billion.