Minehead
The RICH RUN was a drift mine.  The shafts entered the mine horizontally and coal was removed in small hoppers.  The earliest motive power may have been mules but later electric trams pulled the trains.  There was an extensive array of track up on the mountainside as seen in these photos.   According to Widen, An Appalachian Empire, Book 1, there were as many as 50 miles of tunnels and 5 miles of track connected with the mine.  A number of the photos on this page came from the Sigman website and were posted by Charles Dodrill.  They offer a wonderful insite into the operation.
I've made some assumptions relative to the locations of these photos.  It appears that the first are from the South Mine based on the general arrangement and the extensive wood construction.  According to the Sigman website, these were taken in 1925 and that would make them South Mine scenes.
According to this photo the South Mine hoppers were dumped onto the conveyor by tipping the body of the car, like a dump truck.  Compare this with the later rotary dumper below.
The length of the coal train was impresssive, as were the sizes of the structures, all up on the mountainside.
South Mine
According to Theodore Griffith, construction of the North Mine began as early as 1934 hence that date is cast in the concrete opening to one of the shafts visible in several photos (A).

Further, careful comparison of the design of the hoppers in this photo (left) shows they are of the type in the black and white photos above, not of the type in the 1957 photo below, the North Mine era, suggesting old cars were used on the North Mine for a while. 
Photos by Nelson Stover - 1981
North Mine
According to Warden's BC&G book, the original South Mine operated about 30 years.  According the Theodore Griffith, a life-long resident of Dille, in 1939 the south mine operation was closed and the drift mine shafts entered the mountains on the north side of the creek.  The photo below left, from 1957, shows that the method of transferring coal from the hoppers on the North Mine has changed to a rotary process.
Photo by Nelson Stover - 1981
The rotary dumper was housed in a very small shed when compared to the structures on the South Mine.  The dump drum is visible as a silhouette inside the shed and is shown clearly in the abandon photo to the right.  It is also visible (yellow arrow) in the overall view by Marquis of all the abandon structures below.
Charles Dodrill collection - May 1957
A
After considerable discussion with David Marquis and Nelson Stover, both who visited the site of the mine in the seventies and eighties, there remains confusion about the photos on this page.  David recalls that he took the photo at the very bottom of this page by climbing the conveyor that was in place in 1972 and shooting across the valley.  That conveyor would have been on the north side of the valley making the photo one of the minehead of the South Mine.  It clearly shows the rotary dumper visible in the 1957 Dodrill photo...but by 1957 the North Mine was in operation.

One explanation could be that the South Mine migrated from the dump-type cars to the rotary dumper while that mine was still in operation AND a similar rotary dumper was used on the North Mine when it opened.  Additional information would be welcome.
Doug Andre provided these three photos that came from the collection of Bobby Caruthers of the extensive operation at the minehead.  These appear to be of the same vintage as the four images from the Sigman website above.
This photo is from the collection of Loretta Samples.  There is no specific evidence from the photo itself that conclusively places this at Widen although the overhead catenary system is certainly consistent with other photos on this page.

I was struck, however, by the attire of the gentlemen on the locomotives as well as the kerosene lamps.  No matter where the photo was taken it was very early.
A
The photo to the left shows the same mine entrance as the one above it, although the hoppers look to be of a slightly later design. 
Two undated photos from Loretta Samples collection
Thanks to Roland Coluzzi, Sr. for taking this picture (right) and to Roland Jr. for sending it to us!  This is the only color photo I believe I've seen of the South Mine head while in operation.  Notice that these are clearly the same rail cars as in the Dodrill photo above and the rotary dump building is the same.  Notice the bare lightbulbs hanging above the track and the bumper of the pickup track in the lower left.
David Marquis - circa 1972
David Marquis took this photo of the North Mine head after the mine had been abandoned.  It was taken from the opposite side of the valley.  The rotary dumper is visible under what remains of the dump shed (yellow arrow).