Premier Coal has mined in the Collie Basin since 1950. Although the company operated small pits in the 1950’s and 1960’s, major open cut mining did not start until 1970, at the Western No. 5 Mine. Since then, Premier Coal has cleared approximately 2,600 hectares (ha) of forest land.
The Company is experienced and highly successful at rehabilitating completed dumps and mining areas. Revegetation commenced in 1975 and, by 2004, 1,702ha had been rehabilitated, representing 47% of the area disturbed by mining operations. At present, the annual programme varies between 30ha and 200ha depending on clearing, mining and dumping progress. The plan is to rehabilitate at least as much as the annual clearing requirement.
The primary aim of Premier Coal’s rehabilitation programme is to establish stable, compatible landforms revegetated with local, native species. This will allow the original plant and animal communities to become re-established. The second aim is to leave a positive legacy for future generations – such as recreation areas, aquaculture options or conservation outcomes.
Open cut operations in Collie currently result in a final void at the end of mine life. Careful mine planning is done to minimise the size of final voids through backfilling whenever possible. Inevitably, the style, scale and depth of operations requires some out-of-pit dumping, leaving a final void. Premier Coal is well ahead of current best practice with an approach, far beyond compliance requirements for voids, establishing future value-added options for use of the areas.
Closure of mining in the Cardiff Sub Basin left Premier Coal with six significant final voids to address. These ranged in size from 5ha (50,000m² surface area) to over 100ha (1,000,0000 m² surface area), with depths up to 75m.
Currently, Premier Coal is undertaking a major decommissioning and rehabilitation programme following closure of the three underground mines and the Western No. 5 open cut operations. The programme is budgeted to spend around $13 million over five years.
Rehabilitation of an old void at Western No. 3 has involved the removal of unsightly dragline dumps requiring extensive earthworks to produce aesthetically attractive surroundings to a lake environment.
