Mine Water

Abstract

A derelict "valley dyke" tailings pond at the abandoned Mount Wellington Tin Mine, Cornwall, UK. The mine closed before this pond could be used as intended, and it now serves only as a seasonal source of acidic pollution to the Carnon River. The orange high water mark is controlled by decant through the lower of the two redundant draw-off towers; the burgundy low water mark reflects evaporation and seepage through the dam (which is composed of waste rock). Notice the losing battle of Mother Nature to re-establish a healthy fauna: this book is about how we can help Nature to overcome water pollution at mine sites world-wide. (Photo: P.L. Younger).

The Pailaviri Tailings Deposit, Potosí, Bolivia: Extreme Acid Rock Drainage Generation

“…From the metal and sulfate concentrations in waters leaching from the tailings deposit, it was clear that Pailaviri produces an extreme case of ARD (Younger et al, 2002;Watzlaf et al, 2004). Other sites that present similar elevated metal concentrations are Iron Mountain in California, Iron Duke mine in Zimbabwe, and Peña de Hierro in Spain (Nordstrom et al, 2000;Williams and Smith, 2000;Romero et al, 2011).…”

Evaluation of First 1.5 Years of Operation of a Passive Treatment System in Se Oklahom

“…Typical coal mine drainage is characterized by elevated concentrations of dissolved iron, sulfate, and various trace metals and generally exhibits an acidic pH (<4.5) (e.g., Watzlaf et al, 2004 andYounger et al, 2002). Conventional methods of treatment for these waters generally require large amounts of maintenance and can be very cost intensive to sustain.…”

The Role of Dissolved Carbon Dioxide in Governing Deep Coal Mine Water Quality and Determining Treatment Process Selection

“…Ca(OH) 2 or NaOH) and energy (for pumping, dosing etc) to raise pH and rapidly immobilise and remove metals. Passive treatment, in contrast, employs gravity and naturally occurring biogeochemical processes to attenuate mine water pollution (Younger et al, 2002) e.g. constructed wetlands.…”

“…acidity > alkalinity or vice versa) . It is this that will determine the appropriate type of passive system (PIRAMID Consortium, 2003), whether chemicals are required for active treatment and, if they are, the quantities / strength required (Younger et al, 2002). Given the extent of mine water pollution, and the substantial costs of treatment (the UK Coal Authority invested approximately £8 million in mine water treatment schemes in 2004 alone (Jarvis et al, 2005)), there is clearly both an environmental and an economic incentive to ensure treatment systems are correctly designed.…”

“…In the case of mine water discharges this complicates matters, since abandoned coal mine discharges typically contain elevated iron concentrations, and high Al concentrations in the case of the most acidic outflows. In the surface environment Fe +2 iron is oxidised to Fe +3 iron, which subsequently undergoes hydrolysis to form an (oxy)hydroxides precipitate, as illustrated by Equations (2) and (3) (Younger et al, 2002 …”