• Initial pit development to access the in-pit crusher location and installation of the in-pit crusher circuit; and • Commencement of open pit mining. The key phases of earthworks relating to the ESC include: - Enabling works including the construction of the ESC measures. - Vegetation and topsoil removal and the establishment of the southern stockpile. - Excavation of the Gladstone and Winner Hills to create the GOP. The ESC measures are shown on the ESC drawings provided in Appendix B. Updated detailed ESC drawings will be prepared prior to these works commencing. 2.1. Year 1 Refer to ESCP-GOP-001-01 Year 1 will involve initial preparatory activities (e.g. clearing of vegetation) site establishment works, construction of the ESC measures and set-up of the southern stockpile area. In total approximately 7.9ha area will be worked during Year 1, which includes 5.5ha of the Gladstone Hill, 1.3ha of Winner Hill and 1.1ha for the Southern Stockpile. Once the ESCs are established topsoil stripping will commence. Suitable topsoil will be stored in the southern stockpile. As the stockpile is filled to capacity it will be seeded and grassed. A Sediment Retention Pond (SRP-GOP-01) will be established for the excavation works to Gladstone and Winner Hills. This pond will be located between the two hills. Both hills will be excavated in a way that ensures runoff will fall to the SRP. Additional perimeter bunds may also be required to divert clean water away from the site and to convey dirty water runoff to the SRP. Due to the location of the proposed excavations, being on top of hills, clean water diversions will not likely be required. A SRP (SRP-GOP-02) will be established for the Southern Stockpile as detailed on the attached drawings. SRP-GOP-01 – will capture and treat runoff from the Gladstone and Winner Hills. The area of disturbance is approximately 6.8ha. This pond will be built with a maximum catchment area of 7ha. The catchment area for this SRP exceeds the maximum catchment area recommended by TR2009/02. However, in this case a single 7.0ha SRP is suitable and the following components will be incorporated, consistent with TR2009/02. - The SRP will be sized with a minimum storage volume of 3% of 7ha, which is slightly oversized for its 6.8ha contributing catchment area, plus a forebay with an additional 10% storage volume. - Two 1050mm concrete manholes and five T-bars (total) to maintain the required 3L/sec/ha discharge rate. Each concrete manhole will be weighed down with additional concrete, or similar, to stop the manhole from floating. - A 450mm outlet / discharge pipe from each manhole. Rock riprap erosion protection will be installed under the outlet of both outlet pipes. - An emergency spillway sized to convey the 1% AEP rain event. - Chemical treatment to enhance the sediment removal capacity. Multiple floc sheds will likely be required to provide chemical treatment for the 7.0ha catchment area. SRP-GP-02 – will capture and treat runoff from the Southern Stockpile. The area is approximately 1.1ha. This
RkJQdWJsaXNoZXIy MjE2NDg3