how to safely break and removed a belfast sink

I suggest taping the whole surface of the sink with ducktape, well covered and overlapped. Then if you do attempt to break it up it should help prevent what your worried about. Still exercise caution and use all personal protective equipment relevant

I think trying to break the sink in situ is very risky. 1. I would try and remove the sink and Belfast unit as one. This should be possible by lowering the legs and undoing all the fixings, carefully pull out. Salvage the sink by prising upper unit off. You will have fit new unit and sink in the same manner in reverse. The waste hole from underneath usually has a bulbous amount of ceramic so a hole has to be cut into the unit surface that the sink sits on this hole must be large enough to accept the ceramic and also elongated enough so as to enable the sink to be pulled out from the front giving access at the back to connect taps, the sink is then pushed back for waste connection. If no leaks seal the gap between sink and marble with silicon. 2. Try and old saw slipped under the sink to cut/grind out the adhesive. 3. make a sturdy box to slide in the unit and prop up the sink from inside the cupboard leaving access to saw or multi tool to cut through the upper unit panel and detach from the sides. The sink will now be resting on the sturdy box pull out. 4. I don't know what is to the sides of the sink unit can an access panel be cut in the side It could be awkward but super long flexi hoses and pushfit fittings may help. 5. Contact the marble company and explain the problem they must be very new to the trade, They should compensate you. 6. If you do have to break it up I would use a hammer drill to drill a line of holes a couple of inches from the upper edge as close together as possible. (punch the ceramic first to stop drill drift) Use hammer and cold chisel to chop and score between holes Tap the upper 2 inches off in sections. Prise the sink up and off. Well I hope some of these ideas work for you remember goggles and mask. Bye for now