But Coard, an energetic 70-something whose tiny silver-and-auburn locks peek out of a baseball cap, stays. She oversees this unprecedented urban dig like a trustee would a beloved place of worship - documenting, asking questions, standing watch.
"I haven't missed a week," she says.
Who knew this unearthed piece of history could inspire such unwavering passion and dedication?
At first she went mostly to support son, Michael, an attorney whose organization, Avenging the Ancestors Coalition (ATAC), has relentlessly pushed for a slave memorial to be built at the site.
But something unexpected began to happen. With each visit, the connection to the enslaved Africans who toiled there - Hercules, Ona, Austin, Christopher, Giles, Joe, Moll, Paris and Richmond - grew stronger. She bonded with the archeologists who painstakingly sifted through the dirt looking for more clues to our nation's past, calling them by their first names. She became a constant presence to the people who visited the site and were captivated by this shared experience.
For Coard, this was buried treasure come to life.
"This is where George Washington was with his slaves!" she says. "It's like I come here and I turn into a different person."
Since the excavation began in April, thousands have flocked to see the stripped-away foundation of the nation's first executive mansion, the place where Washington and John Adams conducted their presidencies more than 200 years ago.
Kids gaze into the dirt and ask where the president dined. Tourists want to see the foundation of the famous bow window where Washington greeted dignitaries, the window that inspired the oval rooms we see in the White House today.
But it's the story of the slaves' lives that exerts the strongest pull.
The discovery of a lower basement and an underground passageway is not only proof that Washington held slaves, but that he wanted them to remain unseen.
With the Liberty Bell only yards away, the historical hypocrisy slaps you right in the face - a place where exhilarating freedom stood toe to toe with chattel slavery.
"It has become a place where whites and blacks can talk about slavery without a sense of guilt," says Doug Mooney, who's directing the dig.
"You really get a history lesson here. I've learned so much I've had to grow another head," Coard says.
She's usually accompanied by her sun-hatted friend, Esther Phelps, who always has her digital camera at the ready. They make quite the pair - Miss Esther snapping, Miss Irene chronicling, two septuagenarians turned documentarians, witnessing history.
"Irene's like a celebrity," says archeologist Cheryl LaRouche. "We all pay homage to her when she comes."
According to Michael, his mother's only previous form of activism had been raising three children.
"She always voted, was a member of the block club, but she didn't have any strong political positions that I knew about," he tells me. "But I think she saw this as a good fight, a historic fight and ultimately a winning fight."
Her next stop? The Living History Center Archeology Lab at Third and Chestnut. She wants more information about the excavation's findings, and that's the place to go.
But tonight she and Miss Esther have Bible study.
"I wish some young black people would come down here," sighs Miss Esther. "Everybody loves Jesus. But you need to know who you are."
Coard chimes in: "This place gives you the truth and nothing but the truth."
Contact columnist Annette John-Hall
at 215-854-4986 or firstname.lastname@example.org. To read her recent work: http://go.philly.com/annette.