Stephen:
We all flinched upon hearing news of the Los Frailles dam release of tailings and I immediately headed for a personal meeting with Knight Piesold and Hallam, Knight Piesold, the engineering firms heading up our geotechnical and environmental studies. My background is geology, including soils engineering, plus finance.
These consultants, who are part of the bankable feasibility study team of engineers, have studied surface conditions of the existing tailings dam, and features such as water condition in the nearby streams, finding no significant signs of difficulties. More intensive geotechnical and environmental work will be conducted, including drilling to retrieve samples of materials used to construct the earthworks dam, to ensure that it was built as designed.
To date no indications of significant stability or seepage problems have been found. Therefore, it is indicated that the dam can be used (about 4 years capacity remains before raising of the dam will be required) under pre-existing permits.
Fortunately, the drainage area subject to outflow from the tailings dam does not contain highly sensitive natural features (no parks) and very little social infrastructure (mostly a few farm barns or sheds). The watercourses below our dam are small "creeks." Therefore, the dam does not pose a risk to important rivers as did the Los Frailles, whose spillage was diverted to significant rivers in order to save the Donana National Park (Spain).
Your question is important because a major "plus" of this project is that it is fully permitted, which would save many $$$ and much time. We have specifically excluded from our responsibility certain areas containing tailings from old sulphur mining or Roman-era tailings.
RH |
