It is at present producing more than quarter of a million tonnes of aggregate products a year.
The quarry, about 5km south of St Clair Beach, jointly owned by Palmer & Son and Fulton Hogan, has been operating since the 1950s.
Quarry manager Gavin Hartley was contacted, and said the estimated mine life, following a drone inspection, was expected to be through to the late 2050s.
The plant’s products include a range from general aggregate to roadbases, concrete aggregate, blasting sand, sealing chips and railway ballast.
Mr Hartley said the majority of aggregate from Blackhead was sold for use around Otago, but its aggregate was popular for use in exposed, coloured concrete panels and flooring in Christchurch and Auckland.
The plant employs seven people and production has been ramped up in recent years to about 260,000 tonnes a year, with all the crushing plant having been moved closer to the quarry in recent years.
The quarry sits atop volcanic basalt, formed about 10 million years ago during the third eruptive phase of the Dunedin volcanic period.
The quarry had a covenant put in place in 1990, to protect unique rock formations at sea level, hexagonal columns referred to as the Roman baths.
