Business North March 2021

38 | Restoration of lands working well Karen Phelps More than 250 hectares of rehabilitated pasture has already been completed at the Rotowaro mine site. MINING Bathurst Resources C losure planning is an integral part of Bathurst Resources mine plans from the outset. The company has an internal mine closure standard developed with input from interna- tional mine closure experts, which provides guidelines through exploration stages of con- ceptual mine planning to end of mine life care and maintenance of final rehabilitated areas. Previous coal mine restoration in the Waika- to that current Bathurst Resources staff were involved with has been incredibly successful. Renowned British conservationist David Bellamy described the Lake Puketirini park, which was part of the closure and rehabilita- tion of the Weavers coal mine at Huntly and is now run by Waikato District Council, as one of the best examples of juvenile wetlands in the world, says Bathurst group manager environ- mental operations Phil Lindsay who was one of those that worked on the project. “Lake Puketirini has commercial manuka honey production sourced from beehives around the lake and also a commercial deep water dive training school is operating in the lake,” says Phil. “The walkway around the lake is used for fun runs and the lake is used for various water sports including waka ama, fishing and swim- ming. Water quality in the lake is good and it’s a shining example of the good outcomes that can be achieved when mine rehabilitation is done right.” Phil says having staff on its team at Bathurst Resources with previous knowledge of suc- cessful Weavers coal mine rehabilitation has allowed the company to look at including mine pit lakes as part of its mine closure plans with its two main active mines at Maramarua and Rotowaro. It’s a long term project: “It is estimated that our final mine pit lakes at Rotowaro and Mara- marua mines may take between 7-12 years to achieve final water level,” explains Phil. “A significant strip of indigenous riparian planting around the final mine pit lakes will ensure that the lake water quality is protected from storm water runoff.” Bathurst Resources is in discussion with local iwi in terms of final plant species and planting densities. Apart from the mine pit lakes, a significant portion of the final rehabilitation will be re- turning land to pasture. Phil says that this involves careful salvaging and storage of soil during mining to ensure that there is enough to rehabilitate all the required land area. As the majority of the pre-mined land at Rotowaro and Maramarua mines was pasture the objective is to restore back pasture to the same livestock carrying capacity as pre-min- ing, he says. At Rotowaro mine more than 250 hectares of rehabilitated pasture has already been completed and approved by Waikato Regional Council to allow surface run off from these areas to be discharged directly to streams. He says the schedule at Rotowaro mine is to rehabilitate approximately 20 hectares a year ramping up to 50 hectares a year as it gets closer to the end of coal winning when the coal winning fleet and crew will be transferred to rehabilitation. Bathurst Resources employs contractors to control weeds within the rehabilitated areas and uses independent laboratory SGS to un- dertake water quality analysis to ensure water discharges are in compliance. This is coupled with an independent annual bond review on mine closure plans and costs, which is approved by Waikato Regional and “It is estimated that our final mine pit lakes at Rotowaro and Maramarua mines may take between 7-12 years to achieve final water level.” Export outlook - page 40 District councils. Phil says that the rehabilita- tion annual bond is forecast for the next 12 months and the rehabilitation bond quantum is lodged annually with the councils. “This ensures that if the mine had to go in to sudden closure there are financial funds residing with councils to ensure the mine closure works and final rehabilitation can be completed by a third party. “The rehabilitation bonds include financial costs to decommission and remove mine buildings and infrastructure but we will actively seek to sell and reuse buildings and infrastructure to minimise demolition and using up landfill space.” INNOVATIVE ENGINEERING SOLUTIONS 0800 182 222 www.img.co.nz ENGINEERING | HYDRAULICS | MECHANICAL 0800 255 525 www.mcraesglobal.com WHANGAREI TAKANINI GLENBROOK KAWERAU TOKOROA ROTORUA