By Comfort Asemota
The Tapanuli orangutan, the rarest great ape on Earth, survives only in the Batang Toru rainforest of Sumatra, Indonesia. Now, an expansion of the Martabe gold mine threatens to cut directly through its habitat, raising fears of extinction.
A narrow access road snakes through dense meranti, oak, and mahua forests in northern Sumatra. Though modest now, it will soon extend 2km to reach the Tor Ulu Ala pit, unlocking billions of dollars in gold. But this economic boon comes at a steep ecological cost: the potential loss of the Tapanuli orangutan.
“This is absolutely the wrong place to be digging for gold,” says Amanda Hurowitz, coordinator of the forest commodities team at conservation nonprofit Mighty Earth. “And for what? So mountains of gold can sit in vaults far from where they came from.”
The Tapanuli orangutan (Pongo tapanuliensis) was identified as a distinct species in 2017, separate from Sumatran and Bornean orangutans. Fewer than 800 individuals remain, confined to just 2.5% of their historical range. Their fragile habitat overlaps with the Martabe mine, which began operations in 2012.
Dozens of orangutan nests lie near the planned expansion. PT Agincourt Resources, a subsidiary of British multinational Jardine Matheson, began construction on new access roads in late September. One road already comes within 70 meters of a cluster of nests.
For the company, expansion is essential to meet projected gold yields. The Tor Ulu Ala pit could yield at least 460,000 ounces of gold, valued at nearly $2 billion at current prices. Ruli Tanio, vice-president of PT Agincourt, says the mine supports 3,500 employees, 70% of whom are locals, and argues that without mining, the “alternative will be worse” for the orangutans.
Scientists, however, warn that even minor habitat loss could drive the species to extinction. “It doesn’t take much—especially if female orangutans are affected—for the population to collapse,” says Erik Meijaard, director of Borneo Futures. Orangutans reproduce only every six to nine years, making them particularly vulnerable.
Sumatran Orangutan
(Pongo abelii)
Batang Toru Population
Togus, adult flanged male
Batang Toru Forest
Sumatran Orangutan Conservation Project
North Sumatran Province
Indonesia
The Batang Toru forest houses just three Tapanuli populations—the west block, east block, and Sibual-buali reserve—covering an area roughly the size of Rio de Janeiro. Some individuals have even been discovered outside this zone in isolated peat swamps. Human activities, including previous deforestation, hunting, and a Chinese-owned hydroelectric project, have already fragmented their habitat.
The planned Martabe mine expansion would clear an additional 48 hectares of mostly primary forest in a designated key biodiversity area, while the company also pledges to conserve 2,000 hectares and create an offset zone 40km away. PT Agincourt asserts that mining has not directly killed any orangutans in its 13 years of operation and that clearing will be gradual to allow the animals to relocate.
Environmental groups, including the IUCN’s Avoid, Reduce, Restore, and Conserve (ARRC) taskforce, have repeatedly urged delaying construction until a protective plan is agreed upon. While a new memorandum of understanding now allows independent scientific input, conservationists remain skeptical.
“You cannot say that any great ape species is better with mining than without,” says Genevieve Campbell, primatologist and ARRC leader. Meijaard adds: “You can plant thousands of hectares of forest, but you’re still forcing orangutans into limited space, competing with each other in an ecologically constrained area.”
The Tapanuli orangutan, with its distinctive cinnamon-colored hair and broad face, represents the oldest lineage of orangutans—descendants of the first ancestral apes that arrived in Sumatra more than three million years ago. Its survival now hinges on whether economic ambitions can coexist with one of the planet’s most fragile ecosystems.
