Poseidon Bow River Diamond Mine Limited (Poseidon) operates an alluvial diamond mine on part of Lissadell Station, which is at the southern end of Lake Argyle in the Kimberleys. The original mining proposal was for an area of about 500 hectares and operations have been progressing since 1988 under mining lease conditions.
The original mining proposal was not assessed under Part IV of the Environmental Protection Act 1986, but environmental conditions were set under several Works Approvals and Licences under Part V.
This assessment is of a new proposal to expand the mining operation.
Exploration activity has identified a further area of about 400 hectares in low lying country along Limestone Creek, which flows into the Bow River near its junction with the Ord River. Most of this area would have been underwater when Lake Argyle was at its higher levels in the early 1980s and a significant proportion would be underwater if the lake returns to the spillway level. The current low level of the lake provides the opportunity to mine these low lying areas before they possibly become permanently inundated.
The expanded mining operation also involves the construction of a third tailings dam, an increase in the size of the coarse rejects dump and the installation of supplementary water supply bores. The time frame for the completion of these facilities ls not as critically dependant upon the water level of the lake, as is the mining of the low lying area.
