It’s a quarry, Jim, but not as we generally know it. OK, the stuff that comes out of a typical quarry might sometimes start out as solid rock, but by the time it has been processed the individual bits won’t be all that big.

Not so the output of the Wainihinihini quarry (20km inland from Kumara on SH73) operated by Greymouth-based MBD Contracting.

These are seriously big goolies, lumps of granite that weigh an average of five tonnes each – but for some specific applications like seaport protection walls they can go as high as 15-tonnes a stone! In that case they are carted on semi tipulators, and there have been times when a single rock has made up the whole load.

The rocks are not only big, but also way up on hardness. MBD is one of the few companies around that specialises in granite, sometimes called ‘armour rock’. It’s at the top end of minerals (other than diamond) for wear resistance and lack of faulting, making it ideal for seaport entrances and riverbank protection works, where it can withstand the erosion effects of turbulent water environments, while the individual stones are big enough not to be pushed around in those same environments as well.

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