A curious feature in these parts is the presence of «asphalt mines». We’re all fairly familiar with the idea of oil and gas wells but there are all manner of hydrocarbons under the earth ranging from light gasses such as methane, through heavier oils to the extremely heavy and sticky tars and asphalts. You may never have stopped to think about it but all those roads we are so used to driving about on are made of hydrocarbon namely, asphalt.
In this region there has been a long history of asphalt extraction going back over 150 years. Mining stopped in the 1980’s and nature has pretty much reclaimed the mines. Now they are a haven for bats and the occasional Bizipoza tourist that happens that way.
Our adventure began with a bit of a scramble up to the entrance of the mine. It was a hot day and the going was sweaty so we were glad to arrive in the refreshingly cool air that blew softly out of the mine shaft.
This mine was probably abandoned around forty years ago. There is one entrance point which runs horizontally and leads to a large gallery.
Our resident Bizipozatours Geologist, Ibabe Urzelai was on hand to explain the geology. She tells us that this region was at the bottom of a tropical sea around about 50 million years ago. Plankton and mineral sediments that drifted to the bottom of that sea became compacted and over the millennia the minerals formed the characteristic white limestone which we see today. Within that limestone some of the dead organic material became trapped and remains there today as hydrocarbons.
I should imagine that as the price of oil fell these mines became economically un workable. Now that the price of oil is increasing oil companies are once again investigating the possibility of extracting «tight gas» in this region by «hydraulic fracturing». This is highly controversial due to concerns about contamination of underground water quite apart from the dubious economics of extracting such small quantities of a non renewable energy source. For more information see frackingezaraba.org
Apart from all that the mines are a great opportunity to experiment with the camera…
Here you can see some video footage of the area (in Spanish)