Evaluating Rehabilitation of Sand Mined Sites at Tomago, NSW ⎯ Measuring Success and its Criteria

Authors: Suhartoyo, H; Mulligan, DR; Doley, D Download Paper

DOI https://doi.org/10.36487/ACG_repo/605_69

Cite As:
Suhartoyo, H, Mulligan, DR & Doley, D 2006, 'Evaluating Rehabilitation of Sand Mined Sites at Tomago, NSW ⎯ Measuring Success and its Criteria', in AB Fourie & M Tibbett (eds), Mine Closure 2006: Proceedings of the First International Seminar on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 781-790, https://doi.org/10.36487/ACG_repo/605_69



Abstract:
As an increasing number of mining operations approach closure, criteria by which to measure the success of rehabilitation efforts have become increasingly important and several workers have developed ecosystem success indicators (Tongway et al., 1998; Ludwig et al., 2003; Nichols et al., 2005; Grant, 2006). Mined land rehabilitation as ongoing process designed to restore the physical, chemical and biological qualities or potentials of air, land and water systems for post-mining land users (ANZMEC, 2000). Operators, regulators and communities need quantitative data on ecosystem development in order to support decision on mining relinquishment. Both regulators and mining operators are now addressing these issues throughout Australia, despite the relatively few examples of mine closure that have been reviewed publicly and approved (Nichols, et al., 2005). Mining for heavy mineral sands in the Tomago Sandbeds, north of Newcastle, NSW, by RZM Pty Ltd (RZM) has disturbed substantial areas of coastal vegetation. However, a continuous rehabilitation program, initiated by RZM soon after mining commenced in 1972, aimed to return to the mined area plant communities which would have , as far as practicable, similar species compositions and structures to those existing before mining (RZM, 1981; RZM, 2000). The ultimate long-term objective of RZM’s rehabilitation program is dune forests that are similar to undisturbed dune forests in the region. What is yet to be clarified is whether the rehabilitated ecosystems have reached the desired condition or whether the pattern of development indicates that the ultimate goal will be achieved. In judging rehabilitation success, numerous authors have used Odum’s (1969) succession traits as primary attributes (e.g. Ewel, 1987; Aronson et al., 1993; Aronson and Le Floc’h, 1996; Hobbs and Norton, 1996; and see review by Ruiz-Jaen and Aide, 2005), emphasising ecosystem or landscape approach for developing criteria of rehabilitation success (e.g. Tongway et al., 1998). However, in a changing environment, a quantitative, site-specific and process/dynamic approach is increasingly demanded (Parker, 1997; Cumming, 2003; Choi, 2004). In case of RZM, multiple disturbances have contributed greatly to the patterns of development of native forest vegetation on rehabilitated sites not only through the re-mining of a number of rehabilitated areas, but also through the occurrence of fires across the sites. These events raise further questions regarding the feasibility of re-establishing native ecosystems. The ability to judge the success or otherwise of rehabilitation is further complicated by a lack of knowledge on the basic ecosystem processes and the rate of ecosystem dynamics in many areas (Court et al., 1996; Ormerod, 2003; Maestre et al., 2006). To date, few studies have considered the effects of multiple disturbances during succession, especially on mine rehabilitation sites (Brennan, 2003; Ross et al., 2004). Therefore studies of ecosystem development on a rehabilitated mine site is of critical importance, especially when the complexity of rehabilitation progression is compounded by multiple disturbances. In this paper, the development of structural and functional attributes within rehabilitated sand mined sites with multiple disturbances was examined. Characteristics of ecosystem structure and function were accessed against the following criteria: first, the overall trend of condition on the rehabilitated sites should be towards that of a reference site, and second, age-related trends on chronosequence of rehabilitated sites should be repeatable over time. Mine Closure 2006 ― Andy Fourie and Mark Tibbett (eds) © 2006 Australian Centre for Geomechanics, Perth, ISBN 0-9756756-6-4 Mine Closure 2006, Perth, Australia 781

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