CORRECTED-Brazil dam collapse reignites debate over storing mining waste
(Corrects paragraph 20 to Porgera mine "once considered", not is "working on", mixing tailings with coarse waste rock and mud to create a product that can be stored on the surface in dumps, and adds current technology. Corrects paragraph 21 to "a different" wet and dry disposal technology to make clear that Teck Resources does not use the same system as considered at Porgera.)
* Disposing of ore waste big global safety, environmental issue
* Alternative engineering known as "dry stack" often put forward
* Cost, climate can make alternatives costly, unviable
By James Regan and Susan Taylor
SYDNEY/TORONTO, Nov 19 (Reuters) - A deadly mud slide at an iron ore mine in Brazil has reignited calls for safer ways to dispose of millions of tonnes of ore waste held back by man-made dams.
The disaster at the Samarco iron ore mine is only the latest in a series involving tailings - waste in mining parlance - that have devastated the environment, and in the case of Samarco, killed at least 11 people and left another 12 missing.
Tailings are typically a mud-like material and their storage and handling has become a major safety and environmental issue, since they can be toxic and may need to be kept isolated.
The Nov. 5 disaster has been termed an "environmental catastrophe" by Brazil after sending waste across two states and liability could fall on Samarco's joint owners Vale and BHP Billiton . Continued...