HEB Construction required large offsite quarry storage capacity in allotted quarry stockpiles. 600,000 tonnes of aggregate were supplied to this major roading project by Stevenson.

Project name: SH18 Hobsonville Motorway, Auckland

Client: New Zealand Transport Agency

Head Contractor: HEB Construction Ltd

Description: A 6 kilometre, 4-lane motorway, from the end of the North-western Motorway at Hobsonville Road, to the western end of Upper Harbour Bridge in Hobsonville. The SH16 Brigham Creek Extension consists of a 3 kilometre, 2-lane extension of the SH16 North-western Motorway from Hobsonville Road to Brigham Creek Road in Whenuapai.

Project value: $220 million

Duration: 2008 – August 2011, completed six months ahead of schedule.

Head Contractor Project Manager: David Loe, HEB

Requirements: Stevenson Drury Quarry provided large offsite storage capacity for aggregates, ready for delivery to site at short notice. Lime modified MR9 basecourse provided a solution to allow construction to continue during wet winter months. This contributed to early project completion. Stevenson Laboratory provided offsite and onsite testing services, and critical quick turnaround of testing.

Aggregates Supplied: Over 600,000 tonnes aggregate supplied to site – TNZ M/4 AP40 basecourse,   MR9 (MANARC AP40 basecourse) modified with  lime, GAP65, drainage metal,  and included 340,000 tonnes of  subgrade fill materials.

Stevenson IANZ Laboratory

In November 2008 Stevenson established a site-based laboratory in Hobsonville to enable HEB to receive an on-demand testing service with fast turnaround of results. This on-site laboratory completed literally tens of thousands of tests over the course of the project.  At the project’s peak, up to nine staff worked at the on-site laboratory. The accuracy and responsiveness of the laboratory’s work earned high praise from HEB’s Project Manager David Loe. ‘We haven’t had to query the service the laboratory has provided – it was flawless.’

Benefits to Contractor client

Large offsite storage capacity at Drury Quarry.  Dedicated stockpiles of 30,000-40,000 tonnes were pre-tested at Drury Quarry – held in individual 6500 tonne lots over the duration of the project. Keeping sufficient stocks in supply ready for delivery at short notice was essential for the project and required meticulous planning. The specified products were all tested by Stevenson IANZ Laboratory and approved by HEB prior to delivery. Lime stabilised basecourse produced in Stevenson quarry based pugmill enabled winter construction progress to be made, resulting in the project being completed an impressive 6 months ahead of scheduled completion 

Hobsonville Extension Aerial

Hobsonville Motorway near Westgate shopping center

Hobsonville Extension Truck



This project was a finalist in the Roading NZ Excellence Awards 2012. 


At completion, road-surface tests confirmed the pavement as the smoothest in New Zealand, a huge credit to the project team.

Project location


‘There is a high degree of collaboration between Stevenson and HEB and a long-established relationship. We are both family-owned independent businesses. We work in the same area and have similar values and philosophies, which works to our mutual advantage.

‘The pavement design (road structure) was designed around the properties of the metal supplied from Stevenson Drury quarry. To give an example of the level of collaboration, in winter we added one per cent of lime to the MR9 aggregates to make the material easier to use during the winter. Trying to construct roading in winter is fraught with problems. To overcome this we worked together to make the material more user-friendly. Stevenson service has been spectacularly good.’:

David Loe, HEB Project Manager