MMG Rosebery proposes to construct a contaminated water storage pond next to the MMG Filter Plant at Primrose, Rosebery. The pond will act as a major component of the proposed MMG Filter Plant Stormwater Management system, and will require the upgrading of infrastructure at the site to increase stormwater retention capacity. The overall intent of the project is to limit contaminated stormwater overflows to the Primrose area of the Rosebery Township.

The stormwater project will involve the diversion of the catchment in the Filter Plant area and upstream of the Filter Plant below the flume into the Storage Pond. The Filter Plant catchment stormwater is typically high in metals and of low pH. As such, the Storage Pond has been designed as a fully lined storage reservoir to prevent any groundwater contamination. It is proposed that stormwater detained in the catchment pond will be pumped back through the filter plant to the tailings dam.