Content warning: This article contains references to sexual assault.

The film crew was caught in a crossfire. On one side, the Congolese army shot bullets. On the other, striking miners threw stones. Caught in the middle, filmmaker Petna Ndaliko Katondolo and his team sought cover — and then, returned to keep filming. 

Their choice surprised the miners, who welcomed the documentarians’ return, knowing then that the documentarians were truly committed to making their voices heard. 

Years later and an ocean away, the voices of the diggers echoed across an audience at Stanford’s d.school. On April 22, students and community members gathered for the opening night of the second annual Environmental Justice Film Festival to watch “Mikuba” (Cobalt) — Katondolo’s 2025 documentary.

For Katondolo, this was a promise kept. For the audience, it was a powerful introduction to the exploitation underlying the metals and minerals used in our technology. 

The Democratic Republic of the Congo is one of the most resource-rich countries in the world. Beneath its  fertile rainforests, vast grasslands and sturdy plateaus stretch veins of the Earth’s most prized minerals: diamonds, gold, copper, lithium, cobalt. For generations, as global powers sought raw materials to power their empires, they subjected the Congo to devastating violence.  

Most recently, China, the U.S., Canada, Australia and Europe have turned to the Congo to provide the raw materials rapidly accelerating technological advances. Cobalt is essential for lithium-ion batteries, which fuel much of the modern world: smartphones, laptops, and electric vehicles. The Congo produces more than 70% of the world’s cobalt. Odds are, there’s some in your pocket right now.

“Mikuba” follows a group of artisanal miners who labor at the Mutoshi mine, a major cobalt site in the Southern Congo, and reveals the harsh realities of the lives of men and women who dig for and trade in cobalt. The mineral governs nearly every moment of their days: their health, their food, their freedom. Dena Montague, a Stanford lecturer in environmental justice and an organizer of the event, said it was important to bring the story to Stanford to show how cobalt, behind nearly every part of life in Silicon Valley, is differently omnipresent in the lives of the people who produce it.  

After the film, Montague moderated a Q&A session with Katondolo, activist for Congolese rainforest communities Samuel Yagase and co-founder of the American nonprofit Friends of the Congo Maurice Carney. 

Yagase put it simply: “Big corporations are raping the Earth. They are raping the forests. They are raping the air. They are raping everything because of capitalism.” 

“Mikuba” is not only about violence and exploitation. It also depicts the healing derived from memory and tradition. 

Katandolo follows mineral trader Mama Leonece to visit an elder who teaches her about “Basandja,” the ancestral ecology of the Congo. Through ritual and oral history, he reveals traditional methods of mining that honor the Earth: locating mineral deposits with plants, never digging deeper than 30 meters and giving thanks to the gifts of the earth.

Speaking after the film, Katondolo said he wants to help the people of the Congo remember alternative ways of relating to the Earth’s resources. But, he says, “Mikuba” also holds a message for communities beyond the Congo, for those of us in Silicon Valley. He wants the world to stop seeing the Congo only for the wealth in the ground. 

Katondolo closed the night with a reminder: “We are not the cobalt. We are just the Congo people.”

The Environmental Justice Film Festival will conclude May 13 with a Screening of “Inhabitants: An Indigenous Perspective” in the d.school atrium at 5 p.m.