Standing in scorching heat, Mansa waits for the stone breakers to fill a large metal bowl with more than 30 kg (66 lb) of stones and places it on her head. She carries it about 100 metres, climbs two flights of stairs of a house under construction, empties her bowl and walks back for more stones-used to build new villas along Ghana's Gulf of Guinea coastline.
Mansa, a frail 23-year-old, repeats her short but arduous journey time and time again, from 7 am to 4 pm, six days a week. Sundays are for church.
I first saw her with photographer Siphiwe Sibeko when we were on our way to the Essipon stadium, covering the African Nations Cup in Ghana. Coming from Paris, I was stunned to see such a fragile woman doing this kind of work.
Some colleagues say such sights are common in Africa but Siphiwe, a 35-year-old South African photographer who has worked in Mozambique, Zimbabwe, Sudan and Malawi, could not understand why only women were assigned to this task. "I wanted to take the picture because it was something that showed the strength of women. And they were looking after their kids in the meantime, it was amazing," he told me.
Mansa could earn 2.5 Ghana cedis (about $2.5) a day but prefers to receive a monthly salary of 120 cedis-less than one-eighth the average civil servant's pay, and rarely enough for lunch. "We're hungry," she said.
She started work when she was 16 and has two children, Junior, 2, and Michael, 4. Her sister looks after them while her husband works as a taxi driver in the Sekondi area.
Other children stay with their mothers while they crush stones near the stadium. Here, in 35 Celsius (95 Fahrenheit) heat, they play on heaps of stone, surrounded by skinny goats scrabbling for food.
We pass them every day, wave, sometimes stop to chat. They ask where we're from and why we're interested in them. Siphiwe and I feel the world has to know that even though slavery has been abolished, women and teenagers are still being exploited. Around 10 women queue up behind Mansa, also with heavy bowls full of stones on their heads, waiting to climb the stairs.
The process begins along a nearby dirt track, where men reduce 50 kg granite blocks to fist-sized stones with hammers. Women, also wielding hammers, some with dangerously wobbly handles, take over and make the stones even smaller, often crushing a finger or hand.
One woman, holding her face in her hands after being struck by a granite splinter, walks away, blood pouring from a 2-cm cut on her forehead. "It often happens and there's not much we can do about it," says one of the men working on the site.
Ama Yaba, a 54-year-old team leader, picks a few leaves from a tree bearing what she calls cantoti, a spice commonly used in cooking. She chews them, spits them into a small bowl and adds water to make a mixture that will stop the bleeding.
No one here has a work contract.
"Everyone has their own pile of stones," says Ama Yaba. "You come to work whenever you want, you decide when you stop." Mansa and her co-workers say a victory for the Ghana national football team-the Black Stars-makes them happy for days.