This requires that the "The Bigger They Are, The Harder They Fall" puzzle be solved and several builders. Once the Blocking Totem from "The Bigger They Are, The Harder They Fall" is gone, wait and the heathens will drift away to other places. You can then drop builders on the mausoleum to clear the blockage. Towards the end, the purple mask heathen who sits by the mausoleum may try to put the blockage back. Do not worry about it, and just make sure that there are three or more builders clearing the rubble.