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Gilroy Engineering & Mining Projects
©2008 GEM Projects Pty Ltd
Contents
What is Coal Mine Backfill?
Backfill is the process of taking waste products from the coal washery (called rejects and tailings) and making a pumpable paste into the old workings.
As a reject disposal method Backfill is about 5 times more expensive (per tonne of reject) than normal surface emplacement methods so it is not the lowest cost option, unless there is a specific reason. However this increased cost doesn't stop the coal mine being viable, and may actually make some mines more viable due to the cost of existing constraints.
The reasons coal mine backfill might be adopted for reject and tailings disposal include;
- insufficient area on surface to enable disposal of washery rejects over the life of the mine ;
- unable to secure statutoryapprovals on surface to dispose of washery reject;
- the goaf gas management is difficult and complete goaf entombment with a hydraulic backfill is required either continuous or sometimes ;
- the cost of the backfill plant (between $8M and $14M) can actually provide up to $20M to $50M in operational savings as backfill with cement is delivered by a backfill plant via a underground reticulation system to build solid constructed roadways, bulkheads and provide significant improvement to travel times, vehicel wear and tear, cost of graders and swilly repairs and general worker morale.
click on the video below to see Peabody's presentation which won a NSW Minerals Council Award.
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