I think the Mine Ride change was sometime after the incident on May 24, 1984 in which a 5-year-old kid fell (or was pushed) from the ride and fractured his skull when he hit the grass. I don't have any other details except that the kid's name was Patrick Camp.
(source: http://www.worldofcoasters.com/roller_coaster_almanac/may.html#24)
Anyway, I distinctly remember that Mine Ride's height restriction was '48" or accompanied by an adult'. I think there may have also been a sign up there that read, "Please, no hand-held infants" but I may be mistaken.
I wonder if they have considered lowering that one to 46". A number of other rides have also gone from 48" or accompanied to strict 48". The Cedar Downs Racing Derby comes immediately to mind.
--Dave Althoff, Jr.
Who rode both Mine Ride and Cedar Downs before he was 4' tall...
(added URI)
*** This post was edited by RideMan on 8/30/2000. ***