Innovation in the Hurunui Provides New Use for Rock Fall

Te Koa Gravel

Following the November 2016 earthquake, there was notable rock fall along Te Koa Road and significant cracks had developed in the rock face.  Hurunui District Council has worked with contractors to stablise the cliff and make use of the resulting debris by crushing it down for use as gravel on the District’s unsealed roads.

The council led-project involved drilling and blasting rock off the dangerous cliff face, dozing the product onto the road.  Over 7,000 cubic metres of material was removed, with 4,000 cubic metres stockpiled for use on gravel roads. 

Hurunui District Council’s Roading Team Leader says the idea of using the rock as metaling material by crushing it down to 20mm sized stone came about when the good quality of the rock was discovered. 

“The crushing exercise has proved this source to be a good hardstone material with the right kind of fines,” she says.

“This kind of ingenuity is something we’re proud of as we are taking debris that would normally be disposed of, and transforming it into a usable product as the basis for key roading infrastructure in the District. The council is grateful for the cooperation of the McRae family, who have allowed us to stockpile the material on their land.”

The rock material is currently being crushed by Topp Contracting Ltd using their new Impact Crusher.  The gravel is to be used on Te Koa Road and surrounding unsealed roads.