This article first appeared on GuruFocus.

BHP Group (NYSE:BHP) will record a $2.3 billion writedown on its giant Jansen potash mine after another cost and timeline reset at the Canadian project. The latest review showed phase two will now cost $6.9 billion, up from the previous $4.9 billion estimate, adding fresh pressure to a project that has already tested investor patience.

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The world's largest miner moved ahead with Jansen's expansion in 2023, before phase one had even started production, as fertilizer prices surged after Russia's invasion of Ukraine. Since then, potash prices have fallen, while costs across both phases have continued to rise, making the project more controversial among some investors.

BHP approved construction of the Saskatchewan mine in 2021 after years of debate over its large price tag. Phase one is expected to begin production next year, while phase two is now expected to start producing toward the end of 2031. BHP still views Jansen as a long-life potash business that could potentially operate for a century and scale toward the size of its flagship Australian iron ore operations.