Mining is inherently highly impacting, but widely accepted in mining-dominated countries. Rehabilitation of post-mined land on the other hand is not always effectively practiced, in fact it may lack the same efficiency and support experienced during the exploration and opening of a new mining project. The potential environmental impacts of mining are more often than not considered by governments to be balanced by the economic benefits. Fiji as a developing nation relies heavily on economic opportunities, and has recently experienced increased interest in mining and mineral exploration that, potentially, could greatly benefit the country. Despite this increased interest in new mining projects however, there remains little increase in efforts that seek to improve the current practices of rehabilitation for post-mined land.
It is the intention of this research project to first understand and then analyse the reasons behind the lack of, or failure of, such rehabilitation activity and to propose strategies through which rehabilitation of post-mined land in Fiji can be addressed and improved. It aims to achieve this by applying risk-based approaches, which offer a means of identifying the significance of activities or actions applicable to mining activities through qualitative, semi-quantitative and quantitative risk analysis techniques. The objective is to apply risk-based methodologies to assess and evaluate mechanisms of mining administration and practices, as well as rehabilitation methods and approaches that have been applied successfully to post-mined land in a selection of other countries. These countries were selected based on similarities of environmental and climatic conditions, biophysical and to a certain extent social as well as regulatory environments to Fiji. These countries were Australia (Queensland, Northern Territory and Western Australia), Papua New Guinea, Solomon Islands, Malaysia and The Philippines.
The qualitative risk-based approach focuses primarily on the performance of the administration system of mining. It analyses common administrative indicators in order to measure administration performance through a descriptive assessment of likelihood and consequences of deficiencies in the administration of mining that equates to potential risk posed by failing to properly address post-mined land rehabilitation. The resultant qualitative risk matrix allows for better understanding of potential risk generated in post mined land rehabilitation, due to performance failure in mining administration, which subsequently can lead to improved administrative performance and better prioritization.
The semi-quantitative risk-based technique provides a systematic approach to assess and evaluate rehabilitation issues that are identified on site by assessors, who are able to estimate through expert judgement the likelihood and consequences based on conditions, situations observed and circumstances on site. The technique follows a similar approach to that earlier applied for mine closure with some amendments now being tested at six case study sites. Two-way analysis of variance ANOVA demonstrates variable outcomes. Four out of the six sites assessed rejected the hypothesis that there were no significant differences for quantitative risk scores collected. Such outcomes were anticipated given the numerous issues highlighted and assessed. Results confirmed the expectation that different issues were likely to have different scores depending on assessor’s expertise. However when issues were combined under the broad closure issues and re-analysed (Two-way ANOVA) the outcomes show no significant difference in four out of six sites assessed and indicate the sources of variation to be either likelihood or consequence at significant sites. Further examination of the errors for discrete sets of score results enables the source of the variation between scorers to be identified. While ANOVA results highlight certain constraints related to applying such a technique, it never-the-less fails to refute the applicability of the technique for the purpose of determining the risk posed by an identified rehabilitation issue, if post-mined land rehabilitation is ignored. It demonstrates that a number of experienced professionals could reproducibly score likelihood and consequence of selected items relevant to mine site rehabilitation, despite the wide ranging issues identified during post mined land rehabilitation. It also reveals an opportunity for improvement through designing standard semi-quantitative consequences and likelihood tables prior to site assessment, as a guideline for assessors to maintain similarity of variance between scorers.
The project also looks at how environmental bonds are determined for mining projects across the reviewed jurisdictions. The literature review indicates that in all jurisdictions, mining is subject to environmental regulation whereby some form of financial security is required as a condition of mining. Among the jurisdictions reviewed, only the Australian states and territory and the Philippines incorporate risk into the determination of environmental bonds for mining projects, although it is less clear to the public how the risk is actually determined and linked to the bond calculation. A major deficiency identified within other reviewed jurisdictions, is the lack of an effective and efficient environmental bond calculation. This is especially apparent when some of the worst examples of abandoned sites with residual impacts are left as legacies in these areas, such as those case study sites examined in this research. While there is no universally agreed approach for deciding on the form of financial guarantee, the approaches that have been adopted by governments are often considered inadequate to cover the true costs of rehabilitation and not commensurate with project risks.
This research adopts the quantitative risk-based approach as a method to determine environmental bonds for mining projects using the assessment of consequences and likelihood results from the semi-quantitative approach, then incorporating unit cost of materials or activities for local conditions required to fully rehabilitate each issue at net present value. The environmental bond determination is calculated using the sum of the cost for each identified hazard. Risk is determined from the matrix – likelihood (p) × consequence (q) and unit cost, which is calculated from the cost of material or activities needed to rehabilitate an assessed issue / event. Application of this technique to an abandoned mine site in Fiji shows that this approach is able to provide a risk-based estimate for rehabilitation cost. When the same risk-based technique was applied to a newly opened mine site also in Fiji it demonstrated that the approach is also applicable to new mining prospects. The approach has demonstrated potential applicable in the Fijian context which can be implemented locally and ensures that acceptable rehabilitation is achieved.