You might be able to, however not easily like when you put out a simple structure fire.

The ground is riddled with small vents that allow oxygen in. If you were to inject a foaming agent and then flood the space you could eventually lower the temperature below the auto ignition temperature.

Might not be easy. Might not be cost effective right now.

But there is a reason that Pagnotti Enterprises bought the land and I doubt it is because they are looking at turning it into a nature reserve.

As far as I've been able to determine, Pagnotti Enterprises has owned land in that area for a very long time and has no apparent plans to mine there anytime soon. They got this new bit of land because the state renounced the right of way and sold it to the owners of the adjacent land. This wasn't a huge meaningful investment to Pagnotti, but they did get rid of the ruined road itself, probably because it was a tourist attraction and a lawyer said to get rid of it.