A retaining wall with a total retained height of 7.2 metres — supporting a new haul road on a Santos gas-field site 550 kilometres inland from Brisbane. Envirocon® designed, supplied and installed it using the Interbloc® modular block system, and built it in around ten days on site.
At a Glance
| Sector | Mining & Resources |
|---|---|
| Application | Retaining Wall |
| Principal | Santos Limited |
| Main Contractor | Shamrock Civil Engineering Pty Ltd |
| Location | Fairview Resource Reserve — approx. 60 km NE of Injune, ~550 km from Brisbane, Queensland |
| Purpose | Retaining wall supporting a new haul road |
| System | Interbloc® dry-stack modular precast — tiered gravity retaining wall |
| Design | Three-tier, gravity-only (no soil reinforcement or anchoring) |
| Scale | 7.2 m total retained height · up to ~65 m long · ~1,000 tonnes precast |
| Scope | Design, supply, transport & install (AS4903 design-and-construct) |
| Installation | Two crew swings · ~10 install-only days on site · 2026 |
Project Outcomes
7.2m
Total Retained Height
~65m
Maximum Wall Length
3 Tiers
Gravity-Wall Design
~1,000t
Precast Concrete Placed
~13 Days
On-Site Installation
550km
From Brisbane
The Challenge
A Remote Site With No Easy Supply
Fairview Resource Reserve sits at the end of a remote access track in central Queensland — roughly 60 km north-east of Injune and around 550 km from Brisbane — and is served by a fly-in, camp-based workforce. Santos needed a new haul road cut into the terrain, and that road needed a substantial retaining structure behind it: a total retained height of 7.2 metres running up to about 65 metres long.
A conventional cast-in-place or reinforced-soil wall would have meant large footing excavations, imported reinforcement, and hauling wet concrete, formwork and specialist crews to a location with no ready supply — all against a fixed program.
The Solution
A Three-Tier Gravity Wall
Envirocon® designed the 7.2-metre retained height as a three-tier gravity wall built entirely from standard Interbloc® blocks. Rather than a single tall reinforced wall, the height was stepped across three terraced gravity tiers — each resisting load through its own mass, with no soil reinforcement, geogrid or ground anchors required.
That gravity-only approach was the key efficiency: it cut excavation and imported materials, simplified the engineering, and removed the trades and dependencies a reinforced wall would have added on a site where every extra input has to travel 550 km. Standard modular units let the design follow the road alignment across its full ~65-metre length without bespoke fabrication.
Supply & Installation
Placed and Interlocked, Tier by Tier
More than 900 precast blocks — close to 1,000 tonnes — were manufactured off site and freighted in with matched fixing kits. Installation ran over two crew swings for a total of roughly ten days on site.
With no formwork, no on-site pour and no curing, the crew simply placed and interlocked the blocks tier by tier, keeping the wall on the critical path for the haul road rather than holding it up.
The Value in Context
Weighed Against a Conventional Wall
On rate per metre alone, Interbloc® can look expensive. But weighed against what a conventional retaining wall would have required in these ground conditions — the footings, excavation, reinforcement and construction — Shamrock found it came back as a viable, competitive option, with far less on-site risk and complexity in a place that punishes both.
Testimonial
"Interbloc were great to deal with — honest conversations around terms, a willingness to assist commercially when we asked, and good, safety-compliant crews on site. The ease of construction and not needing large footing excavations was the main draw. As with any new product, the next job runs smoother again now the expectations are known."
Chris Abberton, PM Shamrock Civil Engineering
Why Interbloc® for Remote & Mining Sites
Remote & Difficult Access
No large footings, no imported reinforcement and no on-site pour — precast units arrive ready to place, so distance and difficult ground stop being a barrier.
Efficient Engineering
A gravity-only, three-tier design carries 7.2 m of height on its own mass — cutting excavation, materials and trades a reinforced wall would demand.
Speed of Installation
Dry-stacked and interlocked by a compact crew, the wall went up in about ten days over two swings — no forming, pouring or curing on site.
Interbloc® is proven for remote sites and the mining industry. From haul roads and hardstands to bunds, laydowns and water management, the Interbloc® modular system is engineered for exactly the places that are hardest to build — remote, access-constrained and resource-sector sites.
