Well, as I ponder this from time to time I weigh the pros and cons.
...Yes, in 250 years no one has found the mines in the RRG. Nope, no one has found the Swift mines any where else in KY either.
There are several reasons of evidence toward the RRG location... one, Swift and his search party were lost in the late 1700's in the RRG and a local there lead them to safety and tried to nurse Swift back to health. Two, Campton, KY which sits near the head waters of Swift Camp Creek, both were named because a base camp for horses (troths ect.) were found at the site prior to its settling in the very early 1800s. Three, many of the landmarks from the oldest known version of the journal (Becky Timmins had), were on and along Swift Camp Creek and she spent the rest of her adult life searching that area from roughly 1870s-1890s. Four, Col. Harrod disappeared, according to his wife, searching the forks of the KY river for Swift's mine in the 1780s or 90s (which is near Beattyville, KY just South of the RRG). Five, the only known and documented stone carving with the S:J:M (Swift:Jefferies/Jefferson:Mundy) was found on Lower Devil's Creek which runs North-South BETWEEN Beattyville and the RRG/Natural Bridge S.P. areas... Note that there was a intersection of Indian traces very near Beattyville, KY. One of the mines, if they existed, was most probably in this area. No where else in KY can you find a convergence of evidence in an area roughly 15 miles N-S by 8 miles E-W. I have uploaded topo maps and links to topo maps of this region with possible Indian Trace routes based on the topography and others research into the whereabouts of those ancient traces. Those 'highways' had to be used by Swift in and out of the area, believe me it would be almost impossible to take loaded horses/mules off trail in that cliffy area and with the undergrowth in the warmer months.
There may be other locations in KY that his group mined, but the RRG and that general area is the Grand Central Station of Swift evidence. Personally I have witnessed rock falls in the winter out there. Ice breaks the boulders free from the cliff faces regularly, erosion is what created and sculpted that area, an opening the size of a salt keg could have been covered easily by a large tree or rock fall. It could be buried under 20ft of rubble and dirt. The area is riddled with natural cave systems as well.