Heavyweight miners Glencore (OTC:GLCNF) and Rio Tinto (NYSE:RIO) made headlines last week after confirming early-stage talks about the mega merger. The $200 billion deal, which has eluded the market for nearly two decades, now looks closer than ever.

Glencore chief executive Gary Nagle has previously described a combination with Rio as "the most obvious deal in mining," a view long championed by his predecessor Ivan Glasenberg, according to Bloomberg. While earlier attempts stalled, people familiar with the discussions say the current round is materially different.

This time, Rio itself reinitiated talks, driven by growing concern that its iron ore-heavy portfolio risks being left behind as a wave of copper-led mergers sweeps the sector.

Softening Frictions

A key shift is in leadership. Rio's former chief ...