By Jack Caldwell - Mining Engineer - Robertson GeoConsultants

Here is a link to the most fascinating presentation at the Tailings and Mine Waste 2010. It deals with reclamation planning in an area of Spain where mining continued for 2,500 years. That is not a typo: I repeat two-thousand, five hundred years. The presentation was given by Sebla Kabas of the Universidad Politechnica de Cartagena.

All too often we get caught in a short time scale syndromethat approximatesour abilityto conceiveof the passage of time–usually about as long as we live. This presentation demands a bigger perspective from us. I grew up around the Witwatersrand, that area around Johannesburg, South Africa where mining has been going on for about one hundred years. Well maybe it was fifty years only when I was growing up. But 50 or 100 is but a drop in time compared to 2,500.

I went to Spain many years ago to help them with remediation of a uranium mill tailings pile. The Spanish laughed at me when I told them that in the USA we closed such piles in accordance with design criteria that called for stability for 1,000 years. The Spanish told me that was a ridiculously short time and reminded me that a Spaniard was Roman Emperor over 2,000 years ago. The Spanish told me that only in a new land would 1,000 years be considered a long time.

Thus we do well, as we plan vast new mining activities, the oil sands, Pebble Mine, and so on, to think of 1,000, 2,000, and 3,000 year impacts. You do not have to believe in global warming to acknowledge thatsuch time spans do exist and will affect the closed, remediated mine site. Good luck on this one.