The Quarry was completely full of water and a fella from a local shipyard had dumped a load of old Cork insulation in it so it looked like a flat piece of land. We were warned about it by our parents and others so knew it was dangerous. Rumours were someone fell in and was never found.
Us kids would throw stones and what we called the 'Stuff' on the surface would disperse and reveal there really was water there. Then it would quickly get covered over again.Of course I only found out it was shipyard Cork insulation many many years afterwards. No H&S in those far off days.
Today that Quarry is under grassy land just off Hebburn Comps entrance road. I've told my grandchildren about it when I picked them up in the car.