Removal of 5 cubes from Mixer Drum

Worst case scenario happened, long story short, we have roughly 5m3 set in a 10m3 mixer truck drum. It’s only 24 hours old but we’re having a hell of a time chipping it out.

Previously we have used explosives to rectify this (we’re underground miners) and it worked well but this truck is quite new, has tons of fancy electrical/sensors so management is very nervous to hit it with explosives.

Because this truck is only one of two in North America we don’t even think getting a replacement drum is viable within a reasonable time frame.

Did some research and found a few ‘silent explosive’ expansion products that get poured into drilled holes and expand over the course of a couple days, but due to the confinement of the drum I’m not sure if this will just turn it into one big bomb.

Has anyone found a solution aside from jackhammers or drum replacement? Thanks guys.