The Mine Access Hatch covers two tracks near mine #2.  With the tight curves and close proximity of the two tunnels, I had to construct a view block to keep the illusion that they are indeed separate.  I cut small pieces of ceiling tile, and stacked the narrow pieces on end in between the two tracks.  This view block is necessary so that a viewer looking into one tunnel, won't see the headlight from a train running through the other tunnel, and to minimize the amount of light that gets into each tunnel (in other words, if I didn't have a view block, each tunnel would have light from two tunnel portals coming into them.  As it is, each tunnel only has one tunnel portal's worth of light).  The viewblock does not have to go all the way to the ceiling for it to be effective, only as high as you see in the picture below.

The hatches and hills were built as described in the junction and hill access hatch pages and the scenery section.  This is how both Oak Mountain access hatches appear after the hills were sanded down.

I wanted there to be a feeling of trains "disappearing into the void" when they entered the tunnels, and the reverse when they exited.  Therefore, I didn't try to model rock walls inside the tunnels.  In some cases, I used spackling compound to smooth out the walls next to the portals, and in some cases, to fill large voids in the tunnels walls.  But then they were painted black.  If you notice in some of these pictures, I go as far as to paint the ceilings black too.  I don't cover every little crack and crevice in the ceilings, just enough to cut down on the brightness of the area.

The picture to the left shows the extent of black paint in the tunnels.  I do paint every surface of the floor and walls, because the smallest area of white or light gray really stands out against the black walls.  Lastly, I ballast into the tunnel a little more than an inch, and then stop.  When there is no light being shone directly into the tunnel, the somewhat abrupt stop of ballast increases the effect of the track disappearing into the void.

The light gray areas in the openings are covered by the hatches, and do not require painting.  The cut edges of the ceiling tiles really soak up the paint, so I don't paint where I don't need to.  The raw tile soaks up so much paint, that it actually saved me a significant amount of time and paint when I covered the tunnel walls with a thin coat of spackling compound and/or wood filler.

The pictures above and below show the finished hatches and the minor seams that are created.  As with the other access hatch, the seams will be camouflaged by foliage when these areas are scenicked.

The picture above illustrates the edge of the ballast.  The edge is highlighted in this picture because the flash is illuminating the interior of the tunnels.  In person, the effect came out much better than I expected.

In the picture below, the excess glue around the tree trunks can easily be seen.  It is mostly clear, but shows up as white in this picture.  This will be covered with clump foliage once the area is scenicked.

The picture below shows the application of spackling compound and wood filler nearing completion on the two hatches.  I quickly realized that the hatches would be taken in and out repeatedly over the layout's life, and I knew from working with spackling compound in other parts of the layout that it is rather fragile.  So, I used wood filler on the edges for a stronger edge.  The drawback is that the harder surface of the wood filler takes alot longer to sand down.  In the upper middle of the picture, you can see some wax paper sticking out of the back of the mountain.  I put wax paper between the hatch and the opening to allow me to get the level of the wood filler close at the seams, while keeping the hatch from being glued to the opening.  This sped up the process by eliminating a bit of sanding.  Before I had the chance to install the trees to be used as lifting handles, I simply screwed some drywall screws into the hatch as a handle.  The screw hole was easily patched with spackling compound when the surface was painted and ground cover applied.