My paper on the hypothesis of a possible second entrance into Menkaure, published in 2019 can be found here:
The below additional pictures show how Reisner excavated the valley temple in 1910. These pictures show that Howard Vyse never got to the east side in 1837. A clear lighter impression is left how far the stones, fallen casingstones and sand where covered up to the east side of the pyramid and valley temple when Reisner cleared it in 1910.
The hole on the flat area was there in all old excavation pictures. It is unclear if this was the doing of a break in /robber attempt before the casing stones collapsed onto the area and covered it with sand. Clearly someone had the idea to look in the exact same area for an entrance.
I am trying to find sponsors to get me to Egypt with a thermal camera to make thermal images of the flat casing stone area as I suspect there is a second entrance into the Menkaure pyramid. If you think this is worth sponsoring, consider a donation at paypal.me/stijnvandenhoven or via https://www.patreon.com/stijnvandenhoven
Many thanks in advance.