October 2018

Glencore’s approach to rehabilitation

  • By Allyn Hamonet, Coal Assets Australia, Glencore

An overview of Glencore’s rehabilitation approaches and how these are embedded in the company’s culture

In a recent interview, Ken Dixon, Environment and Community Manager at Glencore’s Rolleston Open Cut coal mine, said ‘Mining the coal isn’t the end of it; it’s putting it all back together again.’ Ken’s words perfectly capture the approach taken by the site to rehabilitate mining areas.

Rolleston Open Cut mine is located in the southern part of Queensland’s Bowen Basin, approximately 140 km south-east of Emerald.

Since operations began in 2005, Rolleston Open Cut has placed a strong focus on rehabilitation, with almost 800 hectares (ha) of mined land now rehabilitated and a further 150 ha+ planned for rehabilitation in 2018.

A 220 ha section of this completed rehabilitation recently achieved Queensland Government certification, having met all criteria for sustainable post-mining land use.

In coming years, this area of land, and in fact most of the Rolleston mine site, will once again be used for cattle grazing as it was prior to mining.

Trials conducted at Liddell Open Cut mine, another Glencore site in the New South Wales (NSW) Upper Hunter region, have demonstrated that rehabilitated mined land can successfully support commercial grazing over a sustained period. It provides a key indicator for the future success of Rolleston Open Cut’s rehabilitated land.

In addition to meeting its regulatory commitments of delivering rehabilitation suitable for cattle grazing, Rolleston Open Cut is also trialling the establishment of a sensitive ecosystem known by ecologists as semi-evergreen vine thicket (SEVT).

The SEVT threatened ecological community is endemic to the areas in which Rolleston is located and is listed as ‘endangered’ under the Commonwealth Environmental Protection for Biodiversity and Conservation Act 1999.

The Rolleston trial has established a stable, rehabilitated landform capable of sustaining an SEVT community and is now comparing its progress against two reference SEVT sites undisturbed by mining activity.

Government certification

Rolleston is the second of Glencore’s coal operations to achieve Queensland Government certification for some of its rehabilitation while the mine is still operational.

In 2017, the company’s Newlands Open Cut operation also achieved Government certification for 73 ha of rehabilitated coal mine spoil, or overburden, as it is also known. This was a first for the Queensland coal industry.

Glencore is now working toward certification for other areas of rehabilitation at Newlands, as well as its Oaky Creek complex and at Collinsville, Queensland’s oldest operating mine.

While formal certification of rehabilitation in Queensland provides the wider community with a good indicator of a site’s success in returning land to sustainable post-mining uses, it shouldn’t be regarded as the only gauge of successful rehabilitation either by Glencore or the industry in general.

Mining companies have effectively rehabilitated thousands of hectares of disturbed land.

However, prior to the recent formalisation of a Government certification process – the result of a collaborative approach between the industry, government, regulators and the Queensland Resources Council – there was no agreed benchmark for success.

The certification process now enables mining companies to submit areas for assessment by Government and, over the next three to five years, the industry is confident of not just showcasing many more successful examples of rehabilitation, but also providing Government and the community with greater assurance that this aspect of mining is not being neglected.

A shift in focus

Across all of its coal operations – 17 operational mines in Queensland and NSW – Glencore has for the last two years (2016 and 2017) rehabilitated more land than it disturbed for mining; that is more than 2000 ha, equivalent to almost 1000 Melbourne Cricket Grounds.

In 2018, Glencore again plans to rehabilitate more land than it disturbs with the target exceeding 1350 ha.

The key to these results lies in a shift in focus that began in 2010, when the company (then Xstrata Coal) introduced a more systematic approach to rehabilitation that has seen more challenging rehabilitation targets set and achieved; helped some sites address rehabilitation backlogs; and created a process by which progress towards rehabilitation goals can be measured.

Each of Glencore’s sites is required to prepare an Annual Rehabilitation and Land Management Plan (ARLMP) as part of the budget cycle.

This not only provides for effective planning, but also ensures that rehabilitation programs are resourced, budgeted for, and delivered.

The plans go beyond any regulatory requirement and aim to ensure that at all sites the active mining footprint is minimised and that once mining has finished, land is returned to either self-sustaining native ecosystems, an open woodland, agricultural use or other suitable purposes that meet requirements agreed between Glencore, government and local communities.

Final void remediation at Oaky Creek.
Final void remediation at Oaky Creek.

To implement these rehabilitation plans, an integrated approach involving mine planning, production and rehabilitation functions is required so that rehabilitation work can be incorporated as far as practicable into the day-to-day operation of the mine.

Machinery movement provides an opportunity to integrate any selective material handling requirements and final landform goal increments within the short-range earthmoving equipment forecasts of mine schedulers.

It means efficient utilisation of mining fleets for bulk shaping works and the most cost-effective rehabilitation outcome.

To achieve this, rehabilitation forms an important part of daily mine planning and delivery of rehabilitation is measured against a number of checks and balances in internal reporting that aim to drive strong performance and continual improvement in rehabilitation.

One of the strongest of these are key performance indicators (KPIs) that have been developed and form a part of each site’s performance incentive scheme. In effect, it ties rehabilitation performance to employees’ pockets.

These apply to senior management, mine managers, mine planners, mine production employees and environmental personnel.

A report card for rehabilitation

The development of a Rehabilitation Report Card has also been instrumental in assisting assessment of the status of any rehabilitation area, and collectively all rehabilitation work implemented at that mine, against the set rehabilitation success criteria (also known as completion criteria).

Glencore developed the Rehabilitation Report Card between 2012 and 2014 with the assistance of the University of Queensland’s Centre for Mined Land Rehabilitation (SMI-CMLR).

Formally established in 1993, the CMLR is dedicated to delivering excellence in environmental research, education and awareness to the national and international minerals industry, relevant government departments, non-government organisations and local communities.

The CMLR provides the science necessary to inform decision-making that can minimise risks and maximise opportunities resulting from resource exploration, extraction and processing globally.

The Rehabilitation Report Card established a rehabilitation monitoring process and new automated data analysis tool that can objectively identify the status of any rehabilitation areas and classify the rehabilitation status within one of the following categories:

  • requiring rework (because it will not, by itself or even with maintenance, achieve the required criteria)
  • requiring maintenance (some physical works required to maintain or improve)
  • requiring ongoing monitoring (areas may be ecologically young and/or short of meeting criteria at its present stage)
  • ready to progress through the certification process.

The data is captured and stored in a geographical information system (GIS) database for future reference, and the Report Card (in the form of a coloured map) is produced to show how well rehabilitation areas are performing.

This translates complex rehabilitation ecology into an easily understandable tool, and assists the mine rehabilitation specialists to plan, budget and explain the results from this monitoring to other stakeholders.

The Rehabilitation Report Card process is used by all of Glencore’s coal operations in Queensland and is now being rolled out to NSW mines as well.

One of the key benefits is that all operations follow a standardised, repeatable process. It also removes measurement bias, delivering a robust process with scientific rigour to stand up to future scrutiny.

By embracing the broader principles of sustainable development upon which the CMLR was initially established, a number of Glencore’s sites are already providing benchmark results with their rehabilitation.

A new plan for rehabilitation

At Mangoola Open Cut in the NSW Upper Hunter region the mine has pioneered the incorporation of natural landform into its rehabilitation work, with great effect. It is widely regarded as an industry benchmark. Mangoola’s entire pit disturbance area – some 1300 ha – will be returned to landform and vegetation consistent with surrounding undisturbed land.

Traditional overburden rehabilitation techniques use uniform slope angles and flat top dumps (or hills) with contour drains and drop structures to manage water flow down the slopes. Although this style of rehabilitation met the mine’s approval conditions, it was not considered an appropriate fit for the landscape surrounding Mangoola.

Mangoola mine planners and managers worked with external specialists to develop a mine plan using software based on Geofluv™. Geofluv™ is a method adaptable to computer design programs, which designs landforms similar to surrounding areas that can convey run-off water the same way that a natural landform would. The model is used to develop appropriate dumps and ramps to produce a natural landform.

After the natural landform has been built, locally-occurring vegetation types are selected for establishment, based on similar topography, slope, aspect and topsoil type.

Potential environmental benefits of this approach to rehabilitation include:

  • better water quality through stability of landform
  • reduced erosion potential
  • reduced maintenance due to lack of specific water management structures
  • increased biodiversity due to a range of topographic relief, appropriate planning for vegetation communities and habitat augmentation, which creates a more familiar terrain for fauna species
  • more visual appeal in landform which, over time, should not look like mine rehabilitation.

At Liddell Open Cut, also in the NSW Upper Hunter, ongoing trials have demonstrated that cattle grazing to commercial standards is able to be sustained on rehabilitated mined land.

In part, the trial responded to criticism from some sections of the community who did not believe that land that has been mined for coal could be rehabilitated to sustainable grazing land.

The Liddell trial began in December 2012 with specific objectives:

  • to assess and compare the performance of a rehabilitation grazing site against an adjoining unmined (natural) grazing site across a range of soil, pasture and livestock parameters
  • to inform the development of guidance material relating to completion criteria for grazing rehabilitation areas and management of grazing on
    rehabilitation areas
  • to demonstrate the viability of cattle grazing as a sustainable post-mining land use option to stakeholders.
Figure 1. Actual land rehabilitation versus budget (NSW only 2009).

Performance of the soil and pasture on the rehabilitated land has been closely monitored along with the cattle. Results from the trial have consistently shown that cattle on the rehabilitated pasture are performing better than those on natural pasture and that tropical grass species selected for the rehabilitated pasture are also providing higher quality feed than natural pasture.

The performance of both cattle and pasture will be used to help provide information for other Glencore mine sites, such as Rolleston, as well as the broader industry.

Rehabilitation results across Glencore’s mining operations in both Queensland and NSW demonstrate the benefits of an improved focus on internal planning and implementation, and an equally strong focus on achieving both area targets and quality rehabilitation outcomes.

Delivering this high quality mine rehabilitation is now well embedded in the business culture, so much so that between 2013 and 2017, 4216 ha of the 6087 ha of land disturbance at Glencore sites (almost 70 per cent) has been rehabilitated.

A summary report on Glencore’s rehabilitation approach and results is available from www.glencore.com.au

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