Drone Technology with LiDAR Provides Emergency Assistance

The Project:

A critical situation arose in a large city centre, when a section of the main sewer line collapsed causing a burst pipe and a 13m sinkhole. With the collapsed sewer servicing large parts of the highly populated city, urgent investigation and resolution was required and InterGroup approached the client to offer our support.

The client needed the following:

  • An immediate understanding of the root cause of the collapse and the condition of the surrounding assets
  • A safe means of accessing this information, with too many unknowns to send in personnel
  • Clear visual data from which to derrive the best possible solution

Equipped with cutting-edge drone technology with LiDAR capability, InterGroup offered a proactive and immediate response. When the client confirmed their need for our assistance, we mobilised to site the same day.


Embracing Technology To Enhance Safety And Project Outcomes

Our state-of-the-art drone eliminated the need for human entry and enabled a comprehensive assessment of the pipe network. Using LiDAR, we precisely located and quantified the volume of rubble, while also identifying additional defects such as pipe holes. These findings offered invaluable insights into the extent of the damage, enabling the asset owner to make informed decisions for efficient and targeted remediation.

InterGroup’s rapid deployment of this advanced drone technology played a pivotal role in delivering a swift and effective solution to this urgent infrastructure challenge.


Pioneering Elliptic Sewer Pipe Assessment Using Cutting-Edge Drone Technology

The InterGroup team successfully conducted a comprehensive condition assessment of the Elliptic Sewer Pipe, using our drone equipped with Simultaneous Localization and Mapping (SLAM) technology  – a first for New Zealand. The highly sensitive and precarious work involved navigating four sections of the pipe, covering a total distance of approximately 992 meters.

Over a period of a day and a half, the team’s work and outputs surpassed the client’s expectations – gathering all the required information safely and efficiently. The resulting mapping and imagery allowed the client to gain a full understanding of the damage to the pipe, the state of the debris and to identify additional areas of concern to be factored into remediation planning.

InterGroup’s seamless execution, technical expertise, and commitment to safety were vital elements in the overwhelming success of this highly complex, pressured and challenging project.


New Resource Recovery Facility Construction Underway

Construction of InterGroup’s brand new Resource Recovery Facility is underway!

InterGroup is excited to announce construction of our new, state-of-the-art resource recovery facility is well underway at our Auckland premise. This wet processing plant will be equipped with world-leading dewatering technology with the ability to clean and grade aggregate material – providing maximum recovery and diversion from landfill.

The Challenge

The New Zealand Infrastructure Commission has found that waste from construction makes up between 40 to 50% of all waste sent to landfill – around 4.4 million tonnes annually from construction and demolition sources.

InterGroup, as a leading provider of industrial and infrastructure services to local and central government and private entities, is invested in improving waste diversion through our activities and across the sector.

Waste generated by street sweeping and hydro excavation activities in particular pose challenges when it comes to disposal. This is due to the mixing of materials and contamination levels. To mitigate this, InterGroup has invested in a number of dewatering plants in recent years, going some way toward reducing the volume of waste we send to landfill. However, these plants are limited in their capability to support recycling and reuse. Given this, InterGroup has thoroughly investigated options to improve our waste management – and to contribute to improved environmental outcomes across the sector.

 A Schematic Snapshot of Our Future Facility

Our Solution

InterGroup is constructing an industry-leading resource recovery facility at our Stonedon premise. The technology we have incorporated is world-leading, and a first for New Zealand, with:

  • A dedicated tipping station to ensure maximum dewatering and processing of slurried waste materials. This will produce clean reusable sand, aggregate, and water products.
  • A water cleaning and treatment system which allows up to 90% of process water to be recycled and immediately re-used within the plant.
  • A scrubbing and filtration system that carries out pre-screening, scrubbing, organics removal, sizing, stockpiling, fines recovery and filtrates removal; and
  • A two-stage separation and classification system which includes high-pressure washing to effectively remove contaminants and provide the highest possible quality of final products.

For us, and our customers, this will result in enhanced recycling outcomes and an impactful contribution to achieving waste reduction targets.


The Key Benefits Of Our Facility

  • Partnering with CDE means our facility benefits from the guidance, technology and innovation of global leaders in materials wet processing. CDE has refined their knowledge and products over 30 years in business and delivered over 2000 waste processing projects worldwide.
  • As NZ’s leading wet processing plant it will provide the opportunity to reuse material avoiding disposal to fill facilities.
  • The ability to reuse materials in infrastructure activities will contribute to greener construction.
  • Will support enhanced environmental outcomes with tangible reductions to align with our customer’s environmental targets and support industry wide targets.

Why Choose Us?

This facility is more than just a dewatering plant. It is a comprehensive solution which will clean and process solids – transforming them into high-quality aggregate and sand. These outputs can then be reused on projects.

Employing the most innovative technology on the market, supplied by CDE – global leaders in wet processing solutions for waste recycling and mineral processing – this facility will support maximum retrieval and reuse, and will ensure InterGroup’s new waste processing facility sets the standard in the New Zealand market.

Victoria Street Bridge Repaint and Structural Maintenance

Victoria Street Bridge Repaint and Structural Maintenance

Constructed in  1907, the Victoria Bridge is a 141m long and 35.4m high steel plate girder deck arch across Waikato River linking central and east Hamilton. Exposed to harsh environmental conditions, it requires repainting every 20 – 25 years to provide protection against deterioration and corrosion.

In mid-2022, after a successful tender process, Waipa District Council engaged InterGroup to provide water wash and corrosion protection services, and structural repairs.

Waipa District Council were clear about what they wanted from this project: 

  • A contractor experienced in spot repairs and full repaints of large-scale infrastructure 
  • Minimal disruption over the duration of the project 
  • Robust subcontractor management 
  • A strong environmental performance 
  • Exceptional communication

A Public Heritage Structure

The bridge is a designated Public Heritage structure, and its future was at the centre of some debate during the local elections. Proactive communication of work and progress to Council was vital to ensure they were well-equipped to update interested ratepayers and other members of the community. We worked closely with Council’s appointed Communications Specialist, feeding into regular updates provided on their website and through an E-Newsletter. This proactive approach meant the project was completed without public complaints.


What We Did

This was a complex project, conducted at height, over water and on an operational and highly trafficked road and pedestrian bridge. It required a stringently systematic approach and robust methodology to safely and efficiently deliver the broad scope of works. Works included vegetation clearance and scaffolding setup and wrapping, asbestos encapsulation, water blasting and coating remediation, structural concrete repairs, steel remediation, spot corrosion repairs and bird spike installation. We also provided additional works such as steel crevice sealing, installation of welding strain gauges for traffic impact tests, anchor block repairs, Dexafeet reinforcement, and handrail improvements.

Key challenges were posed by working at height, over water and in high winds. Our rigorous safety and environmental procedures were followed at all times, and our scaffold design and installation process and innovative ‘leapfrog’ staging system ensured safety, efficiency, and on-time completion.

Maximising Value

InterGroup’s commitment went above and beyond the core project. In close collaboration with Waipa District Council we sought to maximise value to the community – carrying out additional arborist work to improve visibility of this landmark bridge, while also providing added protection with the use of anti-graffiti coatings in the more graffiti-targeted areas of the bridge. 

We also achieved a number of efficiencies through staging, methodology and product selection, including: 

  • Our innovative ‘leap-frog’ staging and scaffolding methodology minimised disruption while maximising safety and environmental outcomes. This approach ensured the structural integrity of the bridge was never compromised and meant the bridge could safely remain open and operational throughout. This was an unexpected added benefit for Council, who had anticipated significant disruption from traffic management and bridge and lane closures. 
  • Working with Council and our suppliers, we decided on moisture-cured urethane paint. With its ability to be applied successfully in a wide range of conditions, this product choice significantly accelerated the programme, enabling us to complete by Council’s 2023 deadline despite numerous variations and added scope.

Overall Performance

The project was completed in line with the client’s budget and programme, with a strong health, safety, quality and environmental performance and to the client’s satisfaction.


Client Feedback

We are very grateful to InterGroup for their great work. They delivered on their promises, and provided great value for money. They were very attentive to safety and used the latest technology and techniques. They lead the team of contractors that were needed to get this job completed, and would gladly use them again as the lead contractor. They also positively contributed to the planning of the works to ensure Council got the best value possible.

The bridge was an important and historic link in our district. The community is very happy with the completed job, and the lack of disruption during the works.

Paul Strange, Asset Management Team Leader -Transportation, Waipa District Council

0800 468 379
Mailing Address
PO Box 58087, Botany
Auckland 2163