Glencore’s 11 coal mine rehabilitation case studies
Glencore’s 11 coal mine rehabilitation case studies
In this article:
- Glencore is one of Australia’s largest major coal producers, operating 13 mining complexes across NSW and Queensland – incorporating 17 operating mines and providing work for more than 7,600 people.
- They have adopted a governance approach for effective closure planning, implementing it across their Australian coal operations. Find out about their 11 case studies.
- Learn about their integrated approach to closure governance in this article
- Examples of mining rehabilitation
- See what score you get for your Rehabilitation and Closure program
- Find out about Decipher’s Rehabilitation and Closure solution
Glencore has operated in Australia for nearly 20 years and, following its acquisition of Xstrata in 2013, became one of the world’s largest, diversified natural resource companies. They employ around 146,000 people in 50 countries with involvement in both the resources and agriculture sectors.
Glencore is one of Australia’s largest major coal producers, operating 13 mining complexes across NSW and Queensland – incorporating 17 operating mines and providing work for more than 7,600 people.
Their progressive rehabilitation process
Glencore has land management and rehabilitation requirements in place that aim to minimise their active mining footprint and assist with making sure mined land is returned to either self-sustaining native ecosystems, agricultural use or other suitable purposes that meet requirements set down by the Government.
- The final land use design is done in consultation with our communities – each of their sites prepares a 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 and delivered
- The strong focus on rehabilitation is driven by Senior Executives and cascades throughout the business
- Since 2010, this process has enabled them to set and achieve more challenging rehabilitation targets, has helped addressed rehabilitation backlogs at some sites and created a process which can be measured
- Annual rehabilitation inspections and continuation of longer-term monitoring programs provides a measure of the quality of the rehabilitation works
- As of January 2018, their operations have rehabilitated more than 12,600ha of mined land to native vegetation or grazing pastures
- Cattle graze rehabilitation pastures at some of their sites and an ongoing trial at their Liddell open cut mine in the Upper Hunter of NSW is demonstrating that mined land can be returned to productive pasture
1. Bulga Coal
Located near Singleton, in the NSW Upper Hunter, their Bulga Coal operations recently received approval for a life of mine extension. Based on feedback from local communities, Bulga’s mine plans included provision for a landscaped screen that has been designed to minimise noise and visual impacts from their operations on neighbouring villages.
- The screen runs along the western edge of their open cut mine from one end to the other
- It has been designed to look like a natural landform with the height varying by up to 30 metres; once complete, the screen will be approximately 8km in length and 70 metres at its highest point
- They have committed to re-establishing two endangered ecological communities as part of the rehabilitation across the mine, which includes the screen:
- Central Hunter Grey Box-Ironbark Woodland (2,200ha)
- Central Hunter Ironbark Spotted Gum-Grey Box Forest (250ha)
Clermont is an open cut mining operation located in central Queensland’s Bowen Basin, 12 kilometres from the town of Clermont and 110km north-west of Emerald.
- They have been focused on delivering quality rehabilitation on site through re-shaping of waste rock dumps and addressing rehabilitation backlogs
- Preferred design profiles of the embankments were a tri-linear concave slope with an inward sloping bench configuration
- Each tri-linear “lift” contains gentle slope changes of equal length, while surface water management for each landform has been developed in accordance with catchment and existing conditions
- This mimics how landforms naturally erode, and thus makes this landform more sustainable
Collinsville is Queensland’s oldest coal mine, having operated for almost 100 years. It is located in the northern part of the Queensland Bowen Basin, roughly 270kms south-east of Townsville.
- The mine’s Garrick East Open Cut void was a 20ha area which stored approximately 350 mega-litres of mine-affected water
- The void was rehabilitated in late 2015 with the targeted final land use an open woodland, containing a mix of grass, tree and shrub species
- The void was dewatered before back-filling of the pit commenced, using material sourced from overburden removal at other operational areas on site
- Approximately 1.45 million cubic metres of material was hauled, placed and profiled to form the current Garrick East rehabilitation landform
- The method of back-filling is being implemented at other cut voids on site at Collinsville
Their Liddell open cut operation in the NSW Upper Hunter has been conducting a trial on mined land that has been returned to grazing pasture. The aim of the trial is to demonstrate that mined land can be used as productive pasture post-mining.
- Performance of the soil and pasture on the rehabilitated land is being closely monitored to assess performance of pastures across a range of climatic conditions, and to ascertain that the desired soil fertility and pasture composition is maintained
- The trial began in 2012 and the results from three completed phases to date have shown that cattle on the rehabilitated pasture are performing better than those on natural pasture and that the tropical grass species selected for the rehabilitated pasture are also performing better than natural pasture
Our Mangoola open cut operation was the first in the NSW Upper Hunter to incorporate natural landform in its rehabilitation and is widely regarded as an industry benchmark. The mine’s entire pit disturbance area – some 1,300ha is being 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
- Following a successful natural landform trial in 2012, the mine revised final landform plans for the entire disturbance footprint
- Potential environmental benefits of this project 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, will blend with the surrounding vegetated landform
6. Mt Owen
Mt Owen open cut mine has operated adjacent to Ravensworth State Forest in the NSW Hunter Valley since 1993. The forest is one of the largest areas of remnant woodland in the region. Remnants like these provide habitat for native plants, animals and microbes, included a number of threatened species such as squirrel gliders, spotted-tailed quolls, as well as several species of bats.
- Ravensworth State Forest was used for grazing and as a source of timber for more than 100 years – there has been no logging since 1986 and no grazing since 1995
- Mt Owen has been working with Government agencies and the University of Newcastle to reconstruct forest and woodlands in areas disturbed by mining, and in surrounding biodiversity offset areas that had previously been cleared for grazing
- The rehabilitation and adjoining biodiversity conservation areas being established at Mt Owen will provide an area five times larger than the original remnant woodland
- Providing a linkage to other areas of natural vegetation and corridors along which native animals can move as they search for food and breeding areas
- Around 220 species of native fauna have been recorded in Ravensworth State Forest and the adjoining Mt Owen Complex, including 28 threatened birds, bats and small mammals
- This rehabilitation work has received international recognition
Glencore’s Newlands coal complex has achieved a first in Bowen Basic coal mining history with official Queensland Government certification for rehabilitation of overburden spoil. Glencore has worked collaboratively with the Department of Environment & Heritage Protection to progressively certify 73.48ha associated with part of an overburden dump at Ramp 7.
- The requirements were achieved to provide a habitat to suitable for flora and fauna within overarching objectives of being safe, stable, non-polluting and sustainable.
- Glencore achieved certification in June 2017 for the rehabilitation
- Glencore will be using the key learnings from Newlands to look for additional opportunities to obtain certification in other areas of the site along with its Collinsville, Oaky Creek and Rolleston mines
8. Oaky Creek
Their Oaky Creek coal complex in central Queensland’s Bowen Basin supports two underground mining operations and a coal processing plant. Since the closure of open cut operations in 2006, Oaky Creek has focused on integrating coal processing processes with rehabilitation requirements across the surface operations.
- Raw coal is processed through a coal handling processing plant, producing both product coal and waste coal (tailings)
- This waste product is being returned to the land from which it originated as backfill for previously mined out open cut voids
- Once the volume of tailings and/or coarse reject has reached maximum design fill levels and is stabilised to design specifications, it is capped with loose earth
- Native seed mixes are then sown over these areas and lightly “ripped” to stabilise the surface until sufficient plant growth has occurred
Rolleston Open Cut mine is located in the southern part of Queensland’s Bowen Basin, approximately 16kms west of the Rolleston township and 140km southeast of Emerald. Rolleston mine is surrounded by agricultural land, mainly used for beef cattle grazing and dryland cropping. Open grassland is the dominant vegetation type within the mine and surrounding areas.
- Large areas are being returned to pastures for grazing
- A fundamental component of this rehabilitation work is the management of its topsoil resources, providing essential growth medium for vegetation which helps stabilise rehabilitation slopes that are prone to erosion
- The presence of seven major soil types at Rolleston mine requires topsoil resources to be carefully characterised and handled
- These resources have been comprehensively mapped through chemical and physical analysis and a site guideline has been developed to provide information on each soil type, typical topsoil depths, recommended stripping depth, recommendations for assessing potential for deeper stripping, and recommendation for use on rehabilitation areas
- Rolleston mine has successfully rehabilitated almost 800ha of mined land to grazing pasture
Glencore’s Ulan Coal complex in central-west NSW has a long history of mining, dating back to the 1920s.
- The rehabilitation is providing sustainable outcomes for endangered communities, ecological diversity and protection of water flows and quality for the life of the mine and beyond
- Overburden areas are rehabilitated to specifically support communities of Greybox and Ironbark woodlands, consistent with the pre-disturbance environment
- Seeds for the rehabilitation are sourced from within the Ulan-owned land and processed to high levels of quality control by a local supplier
- Seeding design matches the appropriate community based on the aspect of the rehabilitation landform
- Ulan’s White Box Woodland planting program is one of the largest ever undertaken in NSW, with 100,000 trees planted in offset areas to connect extensive areas of native vegetation to the west of the operations with the Durridgerie State Conservation Area and Goulburn River National Park to the north and east of the site
Westside open cut mine operated on the north-western shores of Lake Macquarie, NSW. The mine closure plan divided the site into different rehabilitation domains with different completion criteria developed for each area.
- Spoils and topsoils were characterised to determine the need for soil ameliorants (e.g. gypsum, lime, fertiliser) and their application rate
- Topsoils or suitable alternatives were spread across areas to be rehabilitated
- Erosion control measures (e.g. catch drains, sediment dams, silt fences, mulches) were put in place to minimise soil loss
- Structures such as tree hollows, logs and other woody debris were incorporated into the final landform to improve the habitat value of rehabilitated areas
- Habitat structures, including nest boxes, were installed where practical
- Recent monitoring found 69 different fauna species within the Westside rehabilitation including seven threatened species such as grey-headed flying fox, masked owl, greater broad-nosed bat, little bent wing bat, powerful owl and squirrel glider
How to drive progressive rehabilitation and closure
Information sourced from Glencore.
Decipher’s Rehabilitation & Closure Solution
Armed with Decipher’s Rehabilitation & Closure solution, including GIS, remote sensing, monitoring and management tools means you can easily capture and analyse a wide range of environmental monitoring data, manage risks and issues around put backfilling, rapid flooding, slope instability and acid generation, and ensure you’re meeting your environmental obligations and compliance with alerts and notifications of exceedances.
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Want to find out more about mine rehabilitation?
- See what score you get for your Rehabilitation and Closure program
- What is mine rehabilitation and closure?
- What are some key challenges facing mine rehabilitation and closure?
- How much does mine rehabilitation cost?
- What are the advancements in mine rehabilitation technology?
- What are some best practice mine rehabilitation methods?
- How to take a macro and micro approach to mine rehabilitation
- What is CRC-TiME?
- How to become an industry leader in mine rehabilitation
- Download this free Guide to Mine Rehabilitation in Australia
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