Monday, 9 May 2016

Fracking for metals

During the final panel discussion at Biohydromet '14 (posting of 28th July 2014) Dr. Jim Brierley, of Brierley Consultancy, USA, felt that future mines might utilise some form of a process similar to the hydrofracturing technology developed by petroleum engineers to release shale gas, thus opening up a buried resource. Benefits could include reducing the footprint of mining and development of new technologies for extraction of critical earth resources.
Now, as described in more detail on MEI Online, BIOMOre, funded by the EC/EU "Horizon 2020" Research and Innovation Program, intends to be a cost efficient and ecological answer to this problem. Its main objective is to develop new technological concepts for the in-situ recovering of metals from deep deposits using controlled stimulation of pre-existing fractures in combination with in-situ bioleaching. Within the scope of this project, methods and procedures of the process will be designed, tested and evaluated in laboratories and in a small test facility in an operating underground mine in Poland. BIOMOre is an ambitious approach including quite a lot of environmental benefits (no waste heaps, no dust exposure, minimum infrastructure on surface, less noise and chemical impact etc.).
At next month's Biohydromet '16 in Falmouth, Prof. Barrie Johnson's team from Bangor University will present a paper discussing the BioMOre design concept, which involves: (i) opening flow channels within the ore body; (ii) acid leaching to dissolve acid-labile minerals; (iii) oxidative leaching under anoxic conditions using a microbially-generated ferric iron lixiviant; (iv) decommissioning to eliminate introduced bacteria and to seal flow channels. Data will be presented from experiments in which a polymetallic ore (Talvivaara, Finland) and copper-rich kupferschiefer (Rudna mine, Poland) have been subjected to indirect bioleaching under laboratory conditions. Results confirm the possibility of using such an approach for deep in situ biomining of base metal ores.
So could this be the future for the minerals industry? As Jim Brierley said two years ago it would need a new mind-set, and how would we manage it to make it work? Biohydrometallurgists would play an important role in advancing new technologies, but obviously not working alone in developing such in situ technology- it would need the involvement of metallurgists, geologists, rock engineers and others. To prepare for this he said that we should be researching how microorganisms behave under high hydrostatic pressures, anaerobic and other conditions yet to be defined. This would be a complex technology only applicable for use with highly specific amenable ore bodies and would need to meet all economic, environmental and safety concerns.
And of course, societal concerns- fracking for shale gas has received tremendous opposition in UK, not only because of a perceived earthquake risk, but also, more reasonably, because of potential groundwater contamination by the reletively benign fluids that are used to open up the cracks. But here we are talking of fracking with acids and bacteria, so there is likely to be a lot ot opposition to be overcome.
Twitter @barrywills


  1. The basic part is interesting, but I am afraid the buzz words do turn me off. Another new (sic) concept, fracking for mines! It is a good idea (upto a point: ), but it is not exactly new the Chinese were using it for copper over a thousand years ago ( ), salt and potash use it on a regular basis as has uranium for over 50 years.

    Perhaps the use of biological basis is new, but the concept of fracking for in-situ mining is older than I am and that is getting older day by day.

    Mike Albrecht, Roberts Companies, USA

  2. 'FRACKING' for any industry (oil, gas or metals) will have a difficult time getting past environmental hurdles. Just yesterday, I watched a W5 video on water injection into the ARBUCKLE rock layer in Oklahoma - when injection stops, the earth quakes also stop. Obviously, any injection will disturb the sub-strata, lubricate the rock layers so that they move, causing EARTHQUAKES. In Canada, FRACKING has been objected to by environmental groups.
    Then if we introduce an acid to that water to extract metals, we start destroying the competency of that rock interval so it collapses OR the acidic solution travels along a weak plain to pollute a water supply located miles away.
    In any event, 'FRACKING' will die as a method of extraction unless a way is developed to offset the negative results from 'FRACKING'.
    While it has been used as 'solution mining' in the salt/potash industries, these industries have had to find ways of supporting the cavities produced by solution mining.

    Louis Bernard, Bernard Mining & Metals, Canada

  3. Sulphur used to be mined using Frash Sulphur methods by Duval and then Pennzoil Sulphur in Texas.
    Osvaldo Bascur, OSIsoft, USA

  4. It will be interesting to see if anyone can come up with an appropriate laboratory scale method for testing fracking and in situ leaching. I looked into this as an option for my PhD studies, but logistically it would be incredibly difficult. I also believe the focus on large low grade deep deposits will be very difficult - getting a low recovery on a low grade ore with large amounts of reagent required. I think the best chance is for small, high grade supergene zones that are too small for conventional mining.
    Greg O'Connor, Curtin University, Australia

  5. In situ mining for Uranium has been happening for a long time, and obviously has real advantages in controlling the product that is brought to the surface. Language seems to be a key issue here as the green lobby has a thing about the word 'fracking'.

    1. Call it what you will, Chris, but the media will call it fracking


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