The original mountain encounter maps were made for a resolution of 640x480px. This mod increases the visible area of the mountain encounter maps to support a resolution of 1280x720px without showing black bars at the top and bottom of the screen. Running the game in even higher resolutions will have visible black bars again, just not as big as originally.
To use this mod, open the ddraw.ini, go to [ExtraPatches] and add "PatchFile[number]=mods\fo1_maps_mountains" at the end of the "PatchFile"-list! The game will now load the additional mod folder.
If there is more than one additional mod, make sure to correctly number the "PatchFileX" entry (1, 2, 3, ...).