Spill numbers don’t add up

Terrace letter writer questions numbers derived from government analysis of Mount Polley spill

Dear Sir:

You’ve been quoted as saying the Aug. 4 collapse of the Mount Polley tailings pond released 10 million cubic metres of water and 4.5 million cubic metres of finely ground up rock and that it is “not an environmental disaster”.

Having read that the tailings pond area is about 16 square kilometres, and knowing that one million cubic meters covers an area of one square kilometre, one metre high, it appears that the numbers are incorrect by a factor of at least 10 to 25 +. At 16 square kilometres and 25 metres deep, the release would have been about 400 million cubic metres of water and silt. If there would be 1 millimetre of precipitation of rain, that would be a sprinkle, 10 mm would be a rain fall, 25 + mm would be a downpour and maybe some local flooding.

One centimetre of snow in the lower main land would result in wet roads, 10 cm would bring out some sand trucks and snowplows, 25 + cm would result in all the trucks out and maybe road closures.

Could you please advise who supplied those numbers, the ministry or was it Imperial Metals, owner of the mine. If it was Imperial Metals, I wonder how accurate the numbers were about the discharge into the tailings pond.

Martin Holzhauer,

Terrace, B.C.