Telecom Ridge Spillway
Delivering Critical Infrastructure at the Argyle Mine Closure – Telecom Ridge Spillway
As part of the Argyle Diamond Mine (ADM) closure rehabilitation works, MDM Mining and Civil was engaged by Piacentini & Son to deliver a key piece of infrastructure: the Telecom Ridge Spillway. This project plays a vital role in safeguarding the long-term environmental stability of the site by enabling controlled overflow from the tailings dam during extreme rainfall events.
Project Overview
MDM was contracted to construct the spillway, designed as a porous rock structure that would channel excess water safely away from the tailings dam. The primary objective was to reduce the risk of dam wall overtopping and erosion — a potential trigger for severe environmental damage, including contamination of Limestone Creek.
This $1.7 million project involved the careful placement of multiple rock layers, each built to precise specifications and tolerances. Work began in late 2024, with a scheduled completion date of March 2025. The project timeline was adjusted to accommodate unpredictable weather conditions and the requirement to keep critical haul routes operational throughout construction.
Engineering a High-Performance Spillway
The spillway’s construction began with the excavation and shaping of the discharge channel, followed by the placement of various rock layers — each layer composed of different size aggregates to allow water to filter through while maintaining structural stability. Trucks dumped coarse rock to bring the spillway back to level, eventually reinstating it as a haul route. Once this was complete, the bypass track was removed, and drainage channels were constructed to link the tailings dam inlets directly to the spillway.
One of the more technically challenging elements was the installation of the Hensman Erosion Protection Layer, completed in January 2025. This layer was built to a tight specification of -10mm/+20mm and was placed using GPS-monitored equipment to ensure consistent application, even on steep, unstable terrain.
Challenges and Complexity
The project pushed the limits of operational complexity:
Tailings surfaces were continually shifting as they dried, requiring adaptive methods.
Steep slopes made it difficult to place layers without disturbing underlying material.
Over 80 individual surveys and approvals were needed due to the phased nature of construction.
The Work Method Statement evolved continually as field experience provided new insight into ground conditions.
Despite these challenges, MDM’s team navigated the project with precision and care. The spillway required some of the steepest earthworks ever attempted at the site. Operators used dozers to cut surfaces to within +10mm/-20mm tolerances — often on soft fill and hard material that needed ripping.
Safety and Success
One of the standout achievements of this project is the zero-incident record — no injuries and no equipment damage — in a demanding work environment that included deep soft tailings, tight access, and complex terrain.
This project not only reinforces MDM’s commitment to safety and quality but also showcases our capability to execute technically challenging work to the highest standard. The Telecom Ridge Spillway stands as a testament to MDM’s reliability in critical closure infrastructure.
Looking Ahead
MDM continues to support responsible mine rehabilitation with a focus on precision, safety, and environmental stewardship. Our work on the Telecom Ridge Spillway demonstrates our readiness to take on complex infrastructure projects that require innovative approaches and a commitment to excellence.
