Since 1989, titanium sands have been mined and processed by Tiwest at the Cooljarloo minesite, approximately 10km north of Cataby, Western Australia.

Possible environmental impacts and management of a proposal to mine additional resources (27200 orebody) located within Tiwest's existing mining lease was detailed in a Public Environmental Review.

Following the release of the EPA assessment report, a statement by the Minister for the Environment was issued to allow implementation of the proposal. The approvals were contingent upon the preparation of four managment plans, one of which was a Surface and Groundwater Management Plan.

Specific commitments associated with the Surface and Groundwater Management Plan for the 27200 orebody required a survey of the Emu Lakes wetland. Emu Lakes is one of a series of permanent wetlands located southwest of the Tiwest mining lease. The wetland is located within the Minyulo Suite as classified in the Ecological Assessment and Evaluation of Wetlands in the System 5 Region.

Completed work 

Work for this project involved the following steps.

1. Flora/fauna assessment

The aquatic fauna (macroinvertebrates and fish) were sampled across a range of habitat types to maximise the diversity of species collected. Aquatic macroinvertebrates was collected with 250µm mesh nets and the biodiversity compared to other wetlands on the Swan Coastal Plain. Associated measurements of water quality (water termperature, conductivity, salinity, redox, dissolved oxygen, pH, nutrients {total P and total N} and turbidity) were made at a series of transects and profiles. Measurements were also made of morphology.

The flora survey of the Emu Lakes wetland will be of floristic composition and structural assessment. Vegetation mapping units were identified based on plant community structural characteristics and dominant species. The distribution of the key plant communities was mapped and each unit will have an associated list of species.

2. Wetland Evaluation

The EPA Bulletin 686 was used as the basis of a complete wetland evaluation.

3. Identification of critical indicators of key ecosystem components

Key floral and faunal (and the interactions between these ecosystem components) were identified.

Stable isotope analyses will be used to determine the structure of the aquatic food web and the relative importance of different primary food resources (for example, macrophytes, terrestrial detritus and algae).

4. A monitoring program to determine impacts associated with mining activities

5. A final hard copy report detailing results and recommendations.