Prasad, A 2011, 'Pillara Mine closure and rehabilitation', in AB Fourie, M Tibbett & A Beersing (eds), Proceedings of the Sixth International Conference on Mine Closure
, Australian Centre for Geomechanics, Perth, pp. 343-350, https://doi.org/10.36487/ACG_rep/1152_36B_Prasad
Detailed planning and diligent management were critical to the successful mine closure and rehabilitation of Lennard Shelf’s Pillara operations. Rehabilitation works commenced during the second half of 2009 and were completed, on schedule and under budget, in October 2010. Remarkably the rehabilitation of Pillara was entirely funded by the in-house sale of the mine’s assets.
The benign, non-acid forming (NAF) nature of the tailings, in combination with geochemical data, led to the design of a three layer cover. An initial layer of limestone waste rock was covered with subsoil and vegetated topsoil to achieve a final cover depth between 475 and 575 mm. Erosion barriers of waste rock were also constructed along the contours of the tailing storage facility (TSF) to direct water to appropriate drainage channels. The TSF cover design was adapted to suit the remaining areas of the Pillara mine site, as required.
Aerial photos taken at the end of the 2010/2011 wet season demonstrate significant vegetation growth over the TSF, box-cut and process plant areas. Monitoring of the site continues and initial results are positive. Lennard Shelf is working closely with the Department of Mines and Petroleum (DMP) towards proving the rehabilitation outcome and achieving a bond reduction.
Lennard Shelf Pty Ltd (2008a) Annual report.
Lennard Shelf Pty Ltd (2008b) Golden Gecko nomination, WA (unpublished).
Lennard Shelf Pty Ltd (2008c) Pillara mine suspension plan, WA (unpublished).
Lennard Shelf Pty Ltd (2009) Civil works Pillara lead zinc mine 2010 rehabilitation programme, Tender document No KP801-127/01, WA (confidential, cited with permission).
Lennard Shelf Pty Ltd (2010) Rehabilitation monitoring plan, Pillara operations, WA (unpublished).
Martin, I.D. (2004) Experimental Estimation of Capillary Rise in Carbonate – rich Sediments, Prepared for MBS Environmental Pty Ltd in relation to the Cadjebut Zinc – Lead Mine Tailings, (unpublished).
MBS Environmental (2008) Pillara mine rehabilitation plan, created for Lennard Shelf Pty Ltd, Perth (unpublished),
MBS Environmental (2009) Geochemical study and rehabilitation measures for the Pillara tailings storage facility, created for Lennard Shelf Pty Ltd, Perth (unpublished), 103 p.
MBS Environmental (2010) Pillara TSF rehabilitation Tier 2 Ecological Risk Assessment, created for Lennard Shelf Pty Ltd, Perth (unpublished), 53 p.