When it comes to integrated mine closure planning, there is no one-size-fits-all approach. Successful mine closure requires an adaptive, agile approach to project execution. That said, there are key phases and stage gates, that when followed, can focus design studies and minimize rework. By following the process laid out below, we ensure our integrated closure projects consider all material variables and potential risks, and result in the ‘best’ returning land-use for our clients and stakeholders every time.
The intended outcome of the first phase of an integrated mine closure project is to determine and assess all project alternatives to help identify the highest value option for our clients. Once this stage is completed, our clients will have a clear picture of the preferred project alternatives and can be confident that all options have been considered.
In this phase, our team will conduct a closure visioning process where we collaborate with key stakeholders to help identify the future returning land-use potential, and key relinquishment requirements. We look beyond just ecological restoration options to consider returning land use alternatives that that will be beneficial economically, environmentally, and socially well into the future. Some examples of returning land-uses that could come out of this closure vision workshop include:
In most cases, the ‘best’ future land use may be a combination of several of these in addition to ecological rehabilitation. At this phase, project definition and engineering designs should be mature enough to kick off stakeholder and regulatory consultation.
In the second phase of an integrated mine closure project, the intended outcome is clear design criteria and closure success objectives. This phase focuses on selection of the preferred alternative, effective risk assessment, and definitions of design criteria.
Risk assessments at this phase can include structured evaluation tools like Multiple Accounts Analysis (MAA) and Failure Modes and Effects Analyses (FMEA). A structured risk assessment approach ensures the identification and appropriate mitigation for all project risks, inclusive of environmental, social, and financial risks.
In this phase, sufficient engineering study and design should be completed to be able to develop an Association for the Advancement of Cost Engineering (AACE) Class 4 or Class 3 cost estimate for the closure project.
The third phase in an integrated mine closure project is detailed design and preparation for construction. Detailed designs are completed, cost estimates are well understood, and operations is engaged and prepared for construction. To successfully move through this phase, our team will have gathered all necessary geotechnical, geochemical, surface water, ground water, and climate data required to develop designs that are suitable to take into construction.
Specifically for closure projects to move into the next phase, it’s important to have the post-closure monitoring and adaptive management strategies determined. At this phase, tender packages and construction specifications should be complete and designs should be mature enough to develop an AACE Class 2 or Class 1 cost estimate.
The fourth phase of a closure project is construction. In this phase, the closure engineers should be on-site to complete quality assurance and ensure that designs are being constructed as outlined in the construction specifications. The closure engineers should also be available to answer any requests for information (RFI’s) and document any design changes that may be required due to field conditions.
An important aspect of the construction and execution phase is as-built documentation. As-built documents are the only records of key internal features of closure landforms and document the field-fit design changes that were made during construction. Having quality as-builts is critical to successful post closure monitoring and future adaptive management.
While as-builts often signify the end of a project, there is a fifth phase in integrated mine closure projects. This is the post closure monitoring and adaptive management phase. This phase is frequently unaccounted for and underestimated in an asset’s lifecycle cost estimate but is required to consider a mine closure project finished and successful.
Many closure projects will have temporary post-closure features like temporary sedimentation ponds or temporary water treatment facilities. During this phase there may be a requirement for additional inspections or erosion repairs. Performance monitoring helps inform as to whether designs are performing as intended.
Effective performance monitoring and adaptive management programs should have pre-defined objectives and trigger points for action. Actionable plans to refine closure designs should be in place prior to the commencement of a performance monitoring program in case it’s determined that the structures are not performing as required.
There is no such thing as too soon to start thinking about mine closure and relinquishment. The earlier mine closure is incorporated into life of mine plans the better. At Okane, we promote the idea of beginning with the end in mind, where the end isn’t mine closure. We consider the end being full site relinquishment to the highest value returning land use.
Integrated mine closure planning brings opportunities and benefits to mine operators that traditional mine closure planning does not. Integrating closure planning with the life of mine plan can minimize material re-handling, decrease long term water collection and treatment costs, create opportunities to accelerate schedule and decrease capital costs by leverage equipment and execution teams already available onsite. Integrating closure projects into operating mine plans creates an opportunity to adapt and pivot as the mine plan evolves.
This not only helps avoid the challenge of closure plans being misaligned with mine plans, but also helps identify opportunities for progressive reclamation and helps reduce post-closure liability. This way, an integrated approach to mine closure helps realize the full lifecycle value of all assets within the mining lease.
For more information on integrating closure planning, please don’t hesitate to reach out to us via our contact page found below. We’d love to connect with you!