As election officials prepare for the largest recount in state history to verify the winner of the U.S. Senate race between Republican Sen. Norm Coleman and DFLer Al Franken, here are questions and answers about the procedure:

Where are the ballots?

Locked securely in Minnesota's 87 counties and several larger cities.

When will the recounting occur?

State law triggers an automatic recount in races decided by one-half of a percentage point or less. Starting Nov. 19, after unofficial results are certified, election auditors in nearly 100 county and city election offices will begin going over each ballot by hand as representatives from each candidate's campaign look over their shoulders.

What are the officials looking for?

The voters' intent. If names are circled or checked, those ballots will go in the proper candidate's pile. Disputed ballots will be sent to the State Canvassing Board. The Canvassing Board will include Secretary of State Mark Ritchie, plus two state Supreme Court justices and two Ramsey County District Court judges who will be named soon. If the board can't agree on which pile a contested ballot belongs, they will vote on it.

How long will the recount take?

Ritchie said Friday that the counting must be done by Dec. 5 and that the Canvassing Board will meet Dec. 16 and hope to finish up by Dec. 19. But things also might depend on legal challenges. A recount after the 1962 gubernatorial election took 139 days.

Could it get messier?

It could. Rumors are swirling that lawsuits could be filed, attempting to wrest the matter out of the secretary of state's office and put into court -- possibly because Ritchie is a DFLer. The 1962 gubernatorial recount went before the state Supreme Court several times before the recount even began.

What's the difference between a recount and a contested election?

Recounts are administrative. Contested elections are civil legal proceedings -- a course that experts say is likely this time because the last two really close congressional races in Minnesota ended up in court: the Arlan Stangeland-Collin Peterson race in 1986 and the David Minge-Mark Kennedy race in 2000.

How do contested elections work?

A judge appoints a DFL observer and a Republican observer and they agree on a third party. As many as 100 of these teams would fan out across the state and count every ballot to determine a voter's intent.

Will the ballots be run through machines?

No. The state law was recently clarified so that all recounts shall be done by hand.

Will the recount process be open to the public?

Yes. Tentative times and places will be announced next week, pending the State Canvassing Board triggering the recount when it meets Nov. 18.

How accurate are the state's voting machines?

Postelection audits in 2006 showed a 99 percent accuracy rate statewide for the optical scanning machines that are used across Minnesota.

How many ballots might have eluded the scanners because the ballots were improperly filled out?

If someone circled Franken's name or underlined Coleman's, rather than filling in an oval, the machines wouldn't count it, but the hand-by-hand review will if the intent was clear. In the recent Supreme Court primary recount, 80 uncounted ballots were "found" out of more than 400,000 cast. The actual outcome was changed by only seven votes because 36 of the "found" ballots went to one candidate and 43 to the other.

Joe Mansky, Ramsey County elections director and an elections expert, said about two of every 1,000 scanned ballots are uncounted for similar reasons. Extrapolating to about 2.9 million votes cast in this Senate election, that could add about 5,700 ballots to the stack.

Who makes errors on their ballots?

Typically, it's older voters and newer Americans, Mansky said. "Anyone under 50 grew up taking standardized tests and knows how to fill in ovals," Mansky said. "Give them a paper ballot and they know exactly what to do."

Older voters grew up voting by hand or lever, so they're newer to oval filling. "The other group is people who don't speak English very well and to whom voting is not intuitive because they might have come from a nondemocratic country and filling in any ballot is new to them," Mansky said.

How often do recounts overturn the initial results?

Recounts are common in smaller, legislative races, and they seldom result in reversals. But it can happen. In the four-month 1962-63 recount in Minnesota, Karl Rolvaag upended Gov. Elmer L. Andersen by 91 votes. In the 2004 governor's race in Washington state, Republican Dino Rossi took a 681-vote lead on election night. Two recounts put Democrat Chris Gregoire in the governor's office by 133 votes.

Closer to home, Melanie Ford looked like the loser when she challenged incumbent Al Mitchell for the St. Louis County attorney's job in 2006. But a four-day recount flipped the results, giving Ford an 88-vote victory.

What about absentee ballots that arrived after Election Day?

Absentee ballots must arrive on or before Election Day. If not, they're ineligible, even if they come in late from military personnel overseas.

Curt Brown • 612-673-4767