Environmentally friendly installations

for CB Civil & Drainage

2020 - 2021

Construction of a new wastewater twin rising main (5.5km) and gravity pipeline (0.5m) from the Cobham Drive Interchange area to connect to the Far Eastern Interceptor (FEI) bulk wastewater system alongside Wairere Drive near to Carrs Rd offramp.

Smythes worked closely with CB Civil to undertake the directional drilling portions requiring highly accurate entry and exit points to connect with open trench works to within 50mm accuracy. Use of 50T, 40T & 30T drill rigs to undertake specific shots, mud recycling to reduce waste. Excellent collaborative relationship, ahead of programme. Due to quality installations, additional works undertaken by Smythes to assist CB Civil where required.  Regular Council and environmental audits due to high profile project achieved excellent results and feedback for Smythe team; completion Oct 2021 – 1 month ahead of programme with 100% increase of the scope of work.
1.1km of drilling at the start by Smythes turned into 3000m of 630mm and 1.5km of 355mm HDPE100 SDR13.6. The longest shot was 420m, where ballast was used.
Challenges included high water table & floating of the 630mm pipe, plus slumping under playground. All CCTV for quality assurance excellent, with provider commenting these are best drill shots ever seen in Hamilton.
A separate team completed the installation of 2 pressure mains under the Kiwrail corridor crossing on Wairere Drive– DN 355 PN 10 PE 100 pipe and DN 630 PN 10 PE 100 using pipe ramming methodology. Successful installation using 250CF compressor.

Watercare - McConnell Dowell

2020 - 2021

The Snells-Algies WWTP Outfall Replacement Project involved & construction of estuary crossing under mangroves and meandering tidal creeks. The drill shot was designed to increase the elevation of the highest point on the pipeline thus making this crossing very shallow for the ground conditions. Max depth of just 15m.

Works comprised the installation of 710mm HDPE pipeline, 520m drill shot through a parabolic curve, with the Horizontal Directional Drilling (HDD) method. Using our American… we installed… existing rising mains. Challenging ground conditions that changed from sticky clay/ fill – Tauranga Group alluvium to Mangakahia complex mudstone.

The pilot hole presented the most challenging aspect of the crossing. Preferred drilling methodologies included the use of mud motors and international steering teams, (who didn’t have access to NZ due to Covid restrictions, so live streamed to site from Australia), wire line steering and high-pressure mud motor; proved impossible to maintain circulation in the fractured rock. Smythe’s experienced team persevered and the estuary was crossed in just three short days, using original methodology, care and belief. 

Watercare - Dempsey Wood

This project was performed for Dempsey Wood after delivering the Bremner Estuary crossing, and a fantastic hockey stick shape drill shot in a twin rising main along Bremner Rd. Smythe Contractors had delivered these previous drill shots which allowed us the opportunity to complete this section of drilling, our team very aware of the high risk and sensitive nature of highway/ estuary crossings.

Successful installation within budget and timeframe (excluding extra works undertaken), which originated from an intricate methodology and geo-tech analysis. Effective communication and cooperation were key. Hydro excavation and close relationships developed early with Utility Providers, saw potential service strikes eliminated 100%. High environmental risk and potential for infrastructure damage, however 0 Environmental or H&S incidents.

Ngawha Generation Ltd, United Civil

As subcontractor to United Civil, Smythes directionally drilled to install 560m of 630mm PE100 SDR11 with our American Augers DD440T. This was achieved by carrying out the pilot bore from the eastern end of the job so as not to have too much rod movement or sinkage, far more predominant at the western end of the drilled alignment, due to the softer materials indicated on bore logs taken.

Various risks were associated. Achieving a 0.5% grade in soft alluvial and variable grounds is difficult over long distances, as ground is not self-supporting of drill rods when many movements are required. Striking an impassable object within the borehole at 20m depth, but still managing to traverse this without tooling breakage within the borehole. Mud design is critical and needed to change during the project to suit the changing ground conditions. Horizontal and vertical alignment with high accuracy was achieved through the changeable grounds; all risks identified, thoroughly explored and mitigated.

Lucas Engineering for Tauranga City Council

Asked by Lucas to assist with our machinery for 2-3 weeks in Memorial Park Tauranga, we were there for 10 months, in full support with our DD440T drill and set up. An extremely complex situation where the issues faced weren’t isolated.

Drill string 1600m long and required coordination of both drill rigs attached to same drill string in creating a bore hole out to 13-1400m.

Challenging ground conditions caused situation where frictional forces on drill rods could only be broken by utilizing 2 drills working in unison at opposite ends of the drill string different ground, an amazingly coordinated team approach. An extremely skilled and experienced team showing dexterity in all aspects of HDD, working with machinery at the highest level to achieve a complex installation.
The successful outcome coupled with the collaborative team approach with our skilled and experienced team led to Lucas asking us to work together again with them at a following Hobsonville contract.

Fonterra Picasso

Construction of a new 13.5km long 355m OD PE100 SDR13.6 Waste Water Rising Main and 63m uPVC communications duct with draw wire and pits.  These works also included various pipe sizes from 355mm down to 150mm HDPE and all its associated electronic control valves which were Directionally Drilled through Edgecumbe township. There were 3 stream crossings and one Kiwi Rail line crossing, which also required the pipeline to be installed by directional drilling.  In between these points up to the Omeheu pump station Smythe Contractors opened trench strings of PE pipeline, which were laid, grouted around the annulus and backfilled every day to make safe for the public and the likes of large stock movements, all this work was completed in methodical steps to finish the pipeline in the time frame required by the meticulous client requirements

On completion of this project a contract windup / review was held with Fonterra.  Fonterra praised the Smythe Contractors team in every aspect and stated at the meeting that Fonterra regarded Smythe's to now be 'Partners for Life' praising Smythe's for taking pride in safely delivering a sustainable solution for Fonterra and their Neighbours.

See our other projects