It was supposed to be a big win for climate activists: another of the world’s most powerful mining companies had caved to investor demands that it stop digging up coal.

And while it’s a particularly stark example, it’s not the only one. When rival BHP Group was struggling to sell an Australian colliery this year, the company surprised investors by applying to extend mining at the site by another two decades — an apparent attempt to sweeten its appeal to potential buyers.

Now, after years of lobbying blue-chip companies to stop mining the most-polluting fuel, there’s a growing unease among climate activists and some investors that the policy many of them championed could lead to more coal being produced for longer. Senior mining executives say the message from their shareholders is evolving to acknowledge that risk, and they’re no longer pushing as hard for blanket withdrawals.

BHP may end up holding on to the Australian mine it was battling to sell, Bloomberg reported last week. Earlier this year, Glencore Plc sounded out a major climate investor group before announcing it would increase its ownership of a big Colombian coal mine, according to people familiar with the matter.

“Everyone in the industry is starting to be more sophisticated, more nuanced and more careful on the way they think these issues through,” said Nick Stansbury, head of climate solutions at Legal & General Group Plc.

Who should own the world’s coal mines is a question that resources giants and their investors may be grappling with for years to come. At the global climate talks in Glasgow, world leaders have fallen short on the U.K. host’s ambition to “consign coal to history.” It continues to dominate the world’s electricity mix and energy shortages in Europe and China this year have only reinforced the message that the world remains deeply dependent on coal.