Five years, lol. That's just from the "official" announcement. I don't remember which movie first had it, but it was on Disney vhs releases as "come visit the new upcoming" Fantasyland at least 9 years from before it was completed. The Fantasyland redo became quite the joke amongst the coaster fanatic forums I haunt as it took Disney the better part of a decade to reskin some areas, build a couple meet and greet huts and a restaurant or two and build one small kiddie coaster in the Mine Ride (meanwhile Knoebels which is basically a father and son team built a family oriented new metal coaster BY HAND in about two years or so) and even places like Dollywood has built better themed family rides than the 7 dwarfs mine ride in a third the time.
Comparing the 7 dwarfs (7D) to Dollywoods Firechaser Express (FCE from now on) which both opened the same time shows how poor Disney's construction and creative have become. 7D is 2000 ft long while FCE is 2,472 ft long however FCE includes not only several magnet launches to build the speed faster but it goes in reverse for significant stretches of the ride. 7D has a handful of animatronics, but FCE has a large fireball and other pyrotechnics along with several nonhuman animatronics (basically a building burning and "falling apart" with the roof and walls collapsing). Both are slow, mild rides capable of any children over 39 inches tall, but because there is a 90ft drop on FCE versus 42ft Max drop on 7D and the frequent use of magnetic launches on FCE for extra acceleration, FCE does not feel anywhere as tame. Having ridden both, FCE is a true "family coaster" where all but the smallest kiddies can safely ride it, yet it is not so terribly unexciting that teens and adults are offput by it. FCE is basically just a smooth, safe for kids but still moderately exciting and well themed (kids LOVED all the fireman theming to see and play with even though it's not what you think of as IP). 7D on the other hand is a typical 1960s-1970s dark ride with the equivalent of a county fair kiddie "coaster" thrown in. There's no excitement for teens or adults and it's no safer (in fact it was so unsafe with multiple test accidents and a couple of real human accidents that 7D had to sharply reduce its one semi-interesting element (the swinging cars) significantly as riders over 6ft were hitting the sides of the course with their arms plus it was already set on fire by fireworks last year). But the kicker is FCE cost $15 million and took less than a year to build (officially announced Aug 2013 and completed March 2014). Meanwhile 7D is estimated to have cost ten times as much ($150 mil of the $400 mil total Fantasyland redo, Disney purposefully never released exact figures as it laughably overran the initial budget and due to money restraints and safety issues multiple interesting design elements were removed or sharply reduced) and took five years from the official announcement and almost ten years from unofficial announcement to be completed. And having been on both (multiple times in the case of FCE), it certainly does not look like 7D cost ten times as much and five times as long, in fact FCE is the FAR better ride even for the kiddies but especially for teens and adults.
