Well I know on my old PC that the game often took that long to load screens. So if your machine is somewhat older and/or has lower-end specs, it's entirely possible to have longer load times like what you've mentioned.

Otherwise, though, people have experienced problems with MTW having long loading times, even on newer/high-end machines. If this the case for you, then I suggest you check out this post I sticked to the top of the Main Hall. It includes a couple different solutions to try. And if nothing else, you can always post your problem in the Apothecary and see if the guys there can help you out.

Either way, I wish you luck!