Mesa A Tailings Storage Facility TSF1 DP05 and DP02

Mesa A was nearing its current capacity. New deposition points needed to be installed to provide additional capacity and allow the mine to keep running.

Polywelding and pipeworks installation, constructing a tailings dam in the Pilbara

Location: Mesa A near Pannawonica, WA

Client: Rio Tinto

Duration: February 2024 – March 2024, May 2024 – June 2024, July 2024 – August 2024

Due to long lead items for the procurement of valves, rubber-lined steel, and non-ASME B16.5 Standard DN550 ANSI300 flanges used at this TSF. The team proposed an alternative accelerated design for deposition point DP05, followed by DP02, for this in-pit tailings dam, which provided approximately 8 months of interim capacity. The works were concurrent with works ongoing at Mesa J. After the long lead procurement items were procured, we returned to Mesa A for the third time to install the materials to meet the original design.

Clearing and establishing pipeline corridors, including relocating a topsoil stockpile;
Constructing windrows;
Supply and install OD560 (DN550) SDR7.4 PN25 PE100 HDPE pipe, continuously welded;
Slotting spigot dropper pipe and installing over the pit wall;
Installed rubber-lined lateral tees (Y-pieces) on skids, which consisted of spools, reducers, air valve assemblies, knifegate valves, mining hose, pre-cast concrete pipe supports and pipe anchors.
The 20t pre-cast concrete pipe anchors required boxing out below the natural surface before craning in, backfilling the surround and compacting.