Open cut coal mining in the Bowen Basin of central Queensland had disturbed in excess of 55,000 ha by the turn of the 21st century and 72,000 ha by 2006. Strong export demand in recent years (since approximately 2000) has led to greater production from existing mines and to a proliferation of new ones. Therefore, over the ensuing decades, the level of mining activity can be expected to increase substantially the areas of erstwhile agricultural land that are disturbed. As mines exhaust their resources, companies will be obliged to achieve acceptable end uses for the various domains at those sites. The possibility of having successfully rehabilitated domains at selected sites certified on a progressive basis holds some appeal. While all stakeholder groups find a return of the land to its prior use (extensive cattle-grazing) an appealing goal, mining companies walk a tight-rope. The legislation under which the early mines were established does not bind them as tightly to the environmentally friendly outcomes as applies to new mines. Nonetheless, recent legislative trends as well as companies’ own policies, encourage them to exceed society’s environmental expectations. Regardless of the end use that is designated, relinquishment is permitted only subject to a satisfactory assessment of the risks to its sustainability. Cattle-grazing is considered as a suitable end use, partly because the return of mined land to its prior use is preferred to its designation to some other use and partly because cattle could serve to reduce the bulk of pasture growth that occurs at some sites, reducing the risk of erosion if an intense fire were to occur followed by heavy rain. Graziers’ primary motivation for seeking tenure of mined land is financial. Factors that determine both a site’s productivity and its commercial ‘worthwhileness’ are examined in this research. The major focus of this research however, is the style of management that the custodial grazier may employ. Since any future custodian is likely to be a local landholder (perhaps the grazier family from whom the land was originally acquired for mining some decades earlier), it is the management style of local farmers that is of primary interest. Some graziers use the land more intensively than others: some with more sensitivity than others. Since the reconstructed landscape is inherently more fragile than undisturbed land, differences in management style could be critical to the sustainability of grazing. Factors driving, or at least being associated with, farmers’ land management decisions were identified from prior research as draft components of a risk assessment model for grazing. A survey of the characteristics and circumstances of Bowen Basin graziers was then conducted with a view to modelling their influence on graziers’ land management style. The survey ascertained the prior probabilities among the target graziers of the elements being modelled. An estimate of the role of these factors in shaping land management decisions was then obtained by eliciting the opinions of industry experts. These processes allowed development of a predictive model that estimates the likelihood of conservative and sensitive land management under various scenarios of site characteristics and grazier-based factors. Output from the model showed that the capital circumstances of a grazier’s business have an influence over the predicted management style of 25% of the difference between best-case and worst-case scenarios. There is a 17% greater likelihood of low-risk grazing where a grazier strongly wants tenure of the land for reasons that go beyond financial gain. The grazier’s underlying values and attitudes to land management account for a further 14%, followed by the operational structure of the business (12%), and the external climatic and economic environment (9%). Interventions that mining companies could implement to increase the likelihood of low-risk management has an influence of 23%. The credibility of the model’s output was evaluated by reference to real-life experiences of graziers who have managed cattle on mined land and their miner counterparts. Consistency of opinion among the consulted experts also contributed to the confidence that can be placed in the model’s findings. The model identifies the sources of risk if currently available mined land is used for grazing. It improves understanding of the situation in a holistic manner, and predicts the likelihood of low-risk grazing management under scenarios of interest to the user. The model identifies actions that mining companies could take to reduce risks associated with graziers’ management style. The model may also guide future rehabilitation work by highlighting features of rehabilitation that would make them more suited to commercially feasible and low-risk cattle production – or by purposefully and transparently planning for cattle-grazing not to be the designated end use.
| Identifer | oai:union.ndltd.org:ADTP/254253 |
| Creators | Robert Maczkowiack |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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