Deep Mines and Spoil Heaps
Nick’s experience related to mines and minewater includes water quality issues from deep mines (mainly coal but also gold), from (colliery) spoil heaps (called bings in Scotland) and from the backfilling of opencast mines.
Key to each of these areas is the design of robust sampling and analysis programmes to avoid problems associated with dissolved metals precipitating out and being filtered out before analysis. This, and an informed review of historical water quality data, reduces the risks of inadequate design of minewater / spoil heap leachate treatment schemes.
Deep Mines
Nick’s work on the quality of water associated with deep mines includes:
- Estimation of the likely quality of water to issue from Whittle Colliery (see World Water, Vol 35, Issue 6, Pages 12-28 on Mine Water Treatment), Northumberland for the Coal Authority. Initial work involved review of historical water quality data and strata sulphide contents to estimate an iron concentration of ~20-40 mg/l compared to a worst case of 900 mg/l that was being quoted before the work. In 1999, trial pumping testing of boreholes sunk into the workings resulted in a sustained iron concentration of ~40 mg/l. Full treatment began in July 2002, with iron concentrations at 40 mg/l initially, but falling from early 2006 to below 20 mg/l from early 2011.
- The Whittle Colliery minewater treatment scheme was designed primarily to treat for iron and secondly for manganese. Nick examined the potential for in-river attenuation of manganese to avoid unacceptable increases in manganese in water drawn from the river at a downstream public water supply abstraction. Nick gave a paper (See Reference #27 on Downloads page) on this work at a conference in November 2002.
- Review of water quality data, empirical analysis and estimation of quality of water likely to result from flooding back of deep gold mines near Johannesburg, South Africa.
Spoil Heaps
Nick has also reviewed the water chemistry and pollution impact on adjacent streams of colliery spoil heaps (bings) in Scotland. Sites include the Riddochhill and Whitrigg Bings for West Lothian Council and the Polkemmet Bings for Ecosse Generation.