An underground gold mine in Central NSW needed new reinforced concrete linings inside its vertical ore passes, the shafts that move mined material down between the mine’s levels. Each lining was designed to be 200mm thick and 2200mm deep, stabilised by rock anchors fixed into the surrounding rock, and built to carry the weight of the heavy loaders working the mine. The problem was space. Each ore pass is just 1560mm across, too narrow for traditional formwork or scaffolding, and the linings had to be installed deep underground in an operating mine without slowing down production.
Advitech designed a reusable access platform that combined crew access, anchor and reinforcement installation, and vertical formwork for the pour in a single structure, reducing the number of temporary works systems needed at each pass. Once the concrete was in, the platform was removed and replaced with a permanent steel ring beam and removable road plate, rated to carry an R2900XE underground loader at its full operating weight of 54,480kg. Because it was built for reuse, the same platform could be redeployed at other ore passes across the mine rather than rebuilt each time.
The constraints that made ore pass installation difficult
Beyond the confined 1560mm diameter, the work faced several constraints at once. Access to the installation locations was restricted, conditions underground were harsh, and crews had to stay safe throughout a job that involved drilling, fixing steel and pouring concrete at depth. The mine also ran ore passes at several levels, so any method that had to be rebuilt from scratch at each location would keep adding time that a working mine could not spare.
The mine needed a team with direct experience delivering structural work in operating underground environments, and the design capability to produce something buildable inside those constraints. Advitech was engaged for its work across regional mine sites and its civil and structural engineering, drafting and project delivery capability.
How Advitech solved the confined-space ore pass challenge
The design was developed in close collaboration with the mine’s team, to ensure it aligned with current operations and the installation plans.
The platform gave crews a stable working position at the ore pass opening, close enough to drill the steel rock anchors horizontally into the surrounding rock and fix the wall reinforcement before the pour.
The platform also carried the vertical formwork for the concrete. At each opening, an inflatable plug system acted as temporary horizontal formwork inside the pass, allowing concrete to be placed at depth without interrupting production above.
With the concrete cured, the platform and its formwork were removed. Protective liner plates were fitted to shield the new concrete from abrasion under mining traffic, and a permanent steel ring beam and removable road plate were installed in place of the platform, giving the mine a finished opening its loaders could drive over.
The standards the work was designed to
Structural work inside an operating underground mine spans several Australian Standards at once, and this project was designed to six of them. Concrete walls and the supporting slab were designed to AS 3600 (Concrete Structures) and structural steelwork to AS 4100 (Steel Structures). The access platform was designed to AS 1657, the standard for fixed platforms, walkways, stairways and ladders. Rock anchor design was undertaken in accordance with AS 4678 (Earth Retaining Structures). Lifting design followed AS 1418 (Cranes, Hoists and Winches) and AS 5221.1 (Cranes, Design Principles for Loads and Load Combinations).
What the reusable platform delivered
The mine gained an installation method that reduced the temporary works needed at each ore pass, and finished infrastructure rated for its heaviest underground vehicles. Specifically:
A repeatable method for confined-space underground installation
Multi-level underground mining infrastructure regularly faces this same combination of constraints. Designing a single reusable structure to carry several installation functions is an approach that can transfer to other vertical infrastructure facing similar access and constructability limits, including ventilation rises and service shafts.
Advitech is a multi-disciplinary engineering and environmental firm headquartered in Newcastle, NSW and supported nationally. Its civil and structural engineering team works with underground mining operators on confined-access and constructability challenges, including ore pass infrastructure. For mining operators who need technical depth without enterprise-scale overhead, Advitech provides direct access to the engineers doing the work.
Need engineering for a confined-access structure?
If you’re working on a structural challenge in a confined underground space, talk to Advitech’s civil and structural engineering team. We provide temporary works and constructability design for ore pass and conveyance infrastructure.
