Mine closure services provider Agreenco has become the specialist rehabilitation and mine closure partner for a large multinational coal miner, for which the company generates rehabilitation quality information on all backfilled and rehabilitated pit areas of the mine.

The decision-support initiative empowers the mine’s managers to know exactly how to optimise rehabilitation operations and what to expect regarding sustainability performance of the recreated landscapes, says Agreenco CEO Fanus Van Wyk.

“Through long-term evaluation contracts and scientific knowledge on the progression of rehabilitated land, we can assist with and advise on improved rehabilitation and closure practices, save the mine substantial amounts of money on maintenance and rework, and continually reduce environmental liability.”

He adds that this information will enable the mine to, after a few years, model rehabilitation outcomes and create a compelling case for closure, as in-field performance information will substantiate closure merits.

“A large elephant in the room is that very few mines have long-term rehabilitation performance information that can be used for closure applications and may take in excess of 10 to 15 years to prove sustainability,” he stresses.

The viability of regeneration and mine end land use projects can also be planned on the basis of this closure information.

He adds that ecological evaluation costs have now become part of this coal mining group’s closure methodology, and routine performance appraisal budgets have become part of the group’s rehabilitation expenditure.

This project will continue for the duration of the life-of-mine, but in about five to ten years, the mine will have sufficient information to start closure proceedings, Van Wyk notes.

Van Wyk also points out that where Agreenco is responsible for project management and implementation projects, they have devised a very successful local enterprise model whereby doorstep contractors are involved in logistics, security, product supply and maintenance works.

“The information indicates that although revegetation has been done, the rehabilitation process is still early work in process, and final closure outcomes can only be considered once the recreated systems demonstrate ecological resilience or commercial end land use value.

“It is fair to assume that this would be the case for many backfilled coal mines, and unless serious interventions in improved rehabilitation are actioned, the rehabilitation efforts of many mines may be in vain without optimisation and maintenance interventions, and mines will have to be re-rehabilitated.”

He adds that the mining industry is becoming more receptive to the value of the correct metrics and closure information that will inform closure applications.

He enthuses that the company’s process can provide a benchmark for “true and conclusive” rehabilitation and closure standards, and that this benchmark can help miners achieve sustainability goals.

“Without good in-field performance data, any rehabilitation project will remain simply just revegetation without any closure merit. Many other coal mining companies are signing up and involving Agreenco as turnkey closure partners where it has been historically proven that through centralised engineering, procurement and construction management processes, much more cost effective and sustainable rehabilitation outcomes can be achieved.”

Gold Tailings Project

Agreenco has also been involved in a gold tailings closure project for several years.

This project has involved Agreenco’s placing and revegetating scientifically designed topsoil covers to reduce slope erosion, eliminate water ingress into the tailings, and inhibit any contamination of the regional area.

Van Wyk says Agreenco has assisted the client in complying with its concurrent rehabilitation commitment, as well as with its in-house closure processes, although the company has not applied for closure.

Agreenco is also the leading  implementer of the ‘store-and-release’ cover, which will be the future closure option for most mine discard and tailings dumps, he enthuses.

These cover systems are designed to retain all precipitated water within benign material overlaying the waste, where the water is removed by evapotranspiration.

“The protection of surface and groundwater systems through surface covers, and the ecological reintegration of mine dumps can be achieved through scientifically designed cover systems. Their construction is specialised and Agreenco proudly leads with the design and application of this line of expertise. Agreenco is extending this service to the coal and platinum markets.”

Van Wyk states that the company has devised the design, costing, implementation, monitoring and maintenance process of the tailings cover.

This has been done in line with the information gathered by frequent, real-time data probes, which has informed the performance of Agreenco’s rehabilitation cover construction process over the past 20 years.

Early detection on cover failure can help clients to act accordingly and save on costs, as well as inform future rehabilitation design interventions, he affirms.

The costs for the project exceed R15-million a year, and are funded through operational expenditure of the tailings construction project.

Van Wyk also highlights that this rehabilitation expense for properly engineered covers need not be accrued to closure liability, as the expenditure on the “store-and-release” cover could offset the future financial liability.

“Agreenco has historical data on the performance of the closure covers derived from on-site trial covers and backed by empirical information – in one specific case now for a period of seven years. We can apply this to many other closure design projects and predict selected outcomes of cover behaviour, discard dump stability, contamination potential and ecological performance of the systems. This is an historical milestone, as no other company designs with real-time performance data at hand.”

He says the implementation of cover systems for mine residue facilities as final closure practice is inevitable despite the denial that pervades the market about this topic. Since cover placement has become standard practice globally, shareholders will take note of local practice, particularly for the approval of new mining projects, he adds.

“Agreenco is growing as a well differentiated mine services specialist and rapidly expanding our brand as long-term mine closure and sustainability partner for companies mining in Africa. We offer turnkey engineering, construction and procurement management and maintenance capability in the closure and environmental space. This means we can contribute to all the facets of our customers’ environmental life-cycle risk components – including land, water, air quality, biodiversity - in South Africa and wherever our customers wish to take us,” he concludes.