In my last blog I showed how different the geochemical composition of a shale is as compared to a sandstone. In my example I compared a typical sandstone from southern Sweden with a typical shale and limestone from southern Sweden. It really is interesting to look a bit closer at some of the elements that can be found in these different rock types.
In respect to the high concentrations of elements shown below in the Table, the Alum (and the Dictyonema) Shale really stand out: Cobalt, Chromium, Copper, Lanthanum, Molybdenum, Niobium, Nickel, Uranium and Vanadium all occur in much higher concentrations than compared to the sandstone or limestone, or even other types of shale. Of course many more interesting minerals and metals can be found in these rock types, but this will be another story. Today I just want – once more – point out that the Alum Shale (or what ever it is called) is a very special type of rock.
For those of you who would like to read a bit more about the geochemical composition of Alum Shale, and especially about what happens when the crushed shale is exposed to weathering, I post here a few of the articles that have been published on the subject. These address the waste in former mines at Andrarum (Skåne), Degerhamn (Öland) and Kvarntorp (Närke) and leakage of highly toxic elements to the groundwater and the Baltic Sea. Interesting, but depressive reading.
Probably not many reflect about the fact that these old mines and their waste deposits cause so much pollution to the groundwater, the Baltic Sea and agricultural land? Given all the experiences and available knowledge regarding the Alum Shale it is really difficult to understand how exploration permits for this type of shale can be granted. It is totally difficult to understand that serious attempts are being made to open a mine in the Alum Shale in Oviken, Jämtland to extract Vanadium. And it is incomprehensible how these new companies, which are hunting for Vanadium, go about to convince politicians and land owners. They talk about green energy and saving of our planet, but never about the dangers of mining Alum Shale. They talk about safe mining and safe extraction, but never about how easy Uranium is leached from weathered Alum Shale. They talk about opening a small mine and then just putting the waste back into the hole, but never about the fact that the land and the ground water will be polluted for decades or centuries to come. So much about green technology and saving of our planet.
Why are politicians and decision makers not making use of the geological and geochemical knowledge that is available? Are they not able to understand what has been written? Are they not able to access all the data that is there? Let’s hope the articles below will help them to understand a bit more.
Opening a mine in a sandstone is a completely different undertaking as compared to opening a mine in Alum Shale. Because a shale is a shale and a sandstone is a sandstone and the two have a totally different chemical composition. Is this too difficult to understand?
Barbara Wohlfarth 