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biodiversity & land management

rehabilitation


The principal aim of rehabilitation at Ulan Mine is to produce a long-term stable landscape returning the landform to an equal or better condition than it was prior to mining operations. The rehabilitation undertaken at Ulan Mine aims to achieve a landscape that is compatible with both the surrounding countryside and native flora and fauna habitats in the area. The pre-mining land capability was classified by the Department of Natural Resources (DNR) as Class 5 land – not suitable for regular cultivation. Examples of potential final land uses for Ulan Mine are dispersed forestry and/or low density grazing. DNR guidelines will be followed so that no downgrading of original zoning will occur.

(Progressive Rehabilitation on reshaped mined areas)
Progressive rehabilitation
on reshaped mined areas

Final landform after mining will be reshaped with the principles outlined in the Mining Operations Plan (MOP). All landform and rehabilitation to date has been done in accordance with these principles.

The rehabilitation completed is consistent with “Ulan Coal Mine Limited Life of Mine Rehabilitation” document, which has been accepted by the DPI-MR. It is also consistent with the current Open Cut MOP.

During 2004/2005 a total of 4.5 hectares of land was cultivated to pasture, whilst a total of 18 hectares of native trees and shrubs were sown. The area to be sown with native tress was ripped and rocks were raked into piles for potential fauna habitat shelters. Soil ameliorates including lime and gypsum was applied at 5t/ha to buffer the acidic nature of the shaped spoil prior to topsoiling to improve the soil structure and prevent surface sealing. A topsoil layer of approximately 100mm was spread out using large dozers and a scraper. A smaller D5 dozer carried out the final ripping to ‘key’ in the topsoil.

Vegetation is cleared prior to mining using a bulldozer. A pre-clearance inspection is undertaken before any clearing of vegetation can take place. Seed may be collected from vegetation species prior to clearing depending on availability. Stripping of vegetation is kept to the minimum width in advance of operations required for safe working conditions, which minimises dust generation, soil erosion and the risk of subsequent deterioration in surface water quality. A buffer zone, a minimum of 50 metres and maximum of 200 metres is maintained between clearing and mining. Trees are either buried or spread as habitat clusters.

After vegetation stripping, topsoil is pushed into windrows by dozers for truck and loader removal for direct application to reshaped areas or if none is available the topsoil is stockpiled. Long-term topsoil stockpiles will be used from time to time during mining and locations will be chosen which will not be subject to disturbance with overburden material. The piles will be maintained with a combination of fertiliser and seed until they are required for use in the rehabilitation program.

Overburden removal and shaping at Ulan Coal Mines Limited (UCML) is undertaken by the dragline assisted by a dozer. Once the dragline has removed the overburden and uncovered the coal, the spoil piles that remain are reshaped to the final rehabilitation design that is included in the Open Cut MOP. The reshaped areas are left to settle for approximately 12 months before the topsoil layer is spread. This is done to allow for settlement of the reshaped area. If any slumping occurs in this timeframe it can be attended to without having to disturb any rehabilitation.

Elements such as drainage paths, contour drains, ridgelines, and emplacements will be shaped in undulating informal profiles in keeping with natural landforms of the surrounding environment. The diverse topography will provide opportunities for a greater diversity of plant species over time. Diversion drains are designed to collect surface runoff from revegetation or disturbed areas. Sedimentation dams are incorporated into the final landform to collect runoff from rehabilitated areas and allow time for suspended sediment to settle prior to the water leaving the site.

Revegetation commences as soon as possible after topsoil has been placed on the reshaped surfaces. The type of revegetation to be used is assessed at each proposed rehabilitation site to determine the most suitable method for that site. Most revegetation undertaken by Ulan Mine is seeded with native trees and shrubs with pasture areas limited to areas around existing infrastructure for quick growth stabilisation of slopes. Predominantly, the native Acacia and Eucalyptus plant species are used for the rehabilitation projects at Ulan Mine.