Taking that volume of stone off the roads and putting in on the unused rail line would give SNCRR a dependable place to launch their freight interests, an important part of their business model.
And, it is better for the environment.
In the early-to-mid 19th century, and again in the mid-to-late 20th century, the open mines bustled with activity, producing high-quality ore and good jobs. The towns where operations were housed, Adirondac and Tahawus, are now only skeletons of their former selves, but still serve as attractions for tourism. Economic development can encourage interest in nature.
The mines still hold a rich deposit of ore. Monetizing that ore may be difficult, but more efficient removal from the deep wild is key to ensuring its success. A similar problem with the cost of production kept Russian oil, much of it locked in tar sands, from being a viable business prospect. Once refining methods improved and demand grew, Russia became a major exporter of oil.
If the National Lead mine could be reopened, it would need a reliable, cheap way to get the ore out. Shipping mine tailings out with SNCRR could be a precursor of much greater things to come.
The environmental groups should not impede that progress.