The Rolling Stones’ ageless rock

These are days of unfinished business for the Rolling Stones as they continue to mine their vault for “lost” material — a fascinating cache of unreleased tracks from the 1977-1978 “Some Girls” sessions arrives in stores next week — and gather their dark powers for their 50th anniversary next year and perhaps another tour.

Lead singer Mick Jagger chuckled when asked about the advice he would give himself as the band sizes up the golden anniversary and its possibilities.

“You can’t be too impressed, I think,” Jagger said. “You could wallow in nostalgia if you wanted, couldn’t you? I don’t think that’d be the right attitude. There are a lot of ideas and things to do, some of them sound interesting, some of them sound possible and some of them sound difficult and some sound outright schmaltzy, to be honest. I don’t really know what’s going to exactly happen — but I’m working on it.”

Photos: Rolling Stones through the decades

The Stones, of course, have been working on something ever since the JFK administration. The band defies the laws of time, human endurance and pop-culture physics, but it remains a spiky alliance, especially after the publication of “Life,” the Keith Richards memoir that got its harshest critique (“a bit bitchy,” “tedious”) from a frenemy named Jagger.

“It was the only bad review we got,” the guitar hero rasped with delight last week, two days after he and coauthor James Fox won the Norman Mailer award for their bestselling memoir. “Ah, what can you do?”

Jagger and Richards sometimes seem a bit like an old married couple who stand together only for family photos and then do so only with thin, hard smiles. But, in separate phone interviews, both are clearly enthused about the release of a tricked-out archival edition of “Some Girls.” Although the June 1978 album sparked some controversy over a lewd line about black women in the title track, “Some Girls” was praised by critics and is considered among the group’s best albums from the 1970s. It includes the hits “Beast of Burden,” “Shattered” and “Miss You.”

A concert film, “Some Girls Live in Texas ’78” will also be released next Tuesday on DVD and Blu-ray as a tie-in to the newly remastered album, which will be available in different editions (there’s a $20 two-disc deluxe edition and also a lavish $143 boxed-set version that includes a hard-cover book, a DVD and vinyl single) and features a dozen previously unreleased songs.

Those tracks were in various stages of completion and polish, and Jagger, Richards and company said it’s been a curious and inspiring exercise to fill in the blanks all these years later.

“It was an interesting autumn kind of project for me,” Jagger said, adding that he was prepared for the labors by the 2010 release of “Exile on Main Street” with a similar bundle of salvaged tracks. “I learned quite a lot from doing the tracks on ‘Exile’ about how you do this without it being too much psychological damage…. The ‘Exile’ ones seemed really quite old and even though this is just seven years later it was just more immediate to me in some ways. This album was so much of a piece while ‘Exile’ was recorded over such a period of time, over maybe three years and different sessions.”