Despite demolition costs contributing up to 50% of total estimated mine closure costs, demolition strategies generally receive little attention and assume that infrastructure will be removed and disposed of in an appropriate manner by a demolition contractor.
Few contemporary closure plans identify or evaluate alternative demolition strategies or provide for further investigation into the development of demolition strategies which contribute to sustainable mine closure outcomes.
Historically, regulators, mining companies and consultants have focused their closure planning and implementation activities on the environmental and rehabilitation aspects of mine closure.
This process has involved the mitigation of potential long-term pollution risks and the reinstatement of landforms which are generally safe, stable and compatible with the surrounding ecosystem.
More recently, in response to growing social pressure and increased triple bottom line accounting, the community or social aspects of mine closure planning and implementation have received increasing attention.
This has resulted in significant advances in the mining industry’s approach to the mitigation of post closure socio-economic impacts and the consideration of community capacity development beyond mining.
While most countries require mining companies by law to make provision for mine closure, provisions for decommissioning have historically been based on the opposing and equally flawed assumptions that assets depreciate to zero and there is no salvageable value, or that cash flow from the disposal of assets would cover the costs of mine closure.
This has resulted in there being little incentive to identify or assess alternative decommissioning strategies.
However, external forces, including land use, commercial, market, regulatory and industry drivers, are now emerging to challenge this thinking and cause mining companies to reconsider their decommissioning strategies and estimate closure costs more accurately.
Four core decommissioning strategies should be considered on a project by project basis:
-
Retention/Alternative Use
-
Re-use/Slae
-
Salvage/Recycling
-
Disposal/Burial
Each strategy should be considered in relation to legal, technical, commercial, social, environmental and economic aspects.
Mining assets are not often viewed as potential non-mining assets in the broader context, however, by engaging stakeholders and the broader community in the early phase of closure planning, alternative uses can be identified which potentially impart a positive legacy, as well as maximising resource utilisation.These could include water supply, sanitation and road infrastructure.
As well as considerations of cost, safety and environmental impact, the biggest constraint, with this strategy is the existence of a third party both willing and able to accept transfer of ownership and liability.
A common, but little understood decommissioning strategy is that of reuse and/or sale where a particular asset is either transferred, or sold to a third party, for use in an alternative location. While there is an established industry around the refurbishment of assets, such as power stations, ball mills, tanks and even processing plants, an understanding of the associated activities and costs is not often integrated fully into closure planning.
Decommissioning activities associated with reuse must include consideration of pre-closure maintenance and repair requirements, the cost of dismantling and relocating, alternative sale methods, such as tender, auction and private treaty, and the value of the asset at the time of decommissioning.
Like reuse or sale strategies, salvage or recycling present potentially significant sustainability benefits in regard to both resource utilisation and material stewardship. With global growth in the salvagae and recycling markets, this can be an extremely profitable undertaking. Improvments in technology now make the removal of materials, even from remote areas, less labour intensive and more efficient.
Disposal and burial is generally considered less labour and plant intensive and more cost effective.
However, the availability of suitable voids for landfill and the legal requirements with regard to contamination and to operate and close such landfills, can prove prohibitive. In addition, disposal and burial strategies do not present any sustainable development upside.
Current market forces, design practices and legacy issues are likely to create uncertainty in the selection of a preferred demolition strategy. There is however great opportunity for the industry to embrace the consideration of alternative decommissioning strategies with closure planning activities and to provide a foundation for more sustainable outcomes and financial certainty in the future.
© Sinclair Knight Merz
Requests to re-publish achieve articles should be made via information@globalskm.com
For copyright and disclaimer notices, see Terms of Use.
Who does this affect?
Anyone concerned with identifying the best mine closure option for their site.
What do I need to do?
Be cognisant of the four core decommissioning strategies of retention/alternative use; reuse/sale; salvage/recycling and disposal/burial and their relative environmental, social and economic impacts.
Author: Darren Murphy
Darren is SKM’s Manager of Environmental Mining Services, also based in Perth. Darren has over 15 years experience in environmental research and management within the mining and transport industries with particular expertise in operational management including the development of environmental management systems and programs.
© Sinclair Knight Merz
Requests to re-publish achieve articles should be made here