Fracking up the Karoo

Much has been said and published in the papers in recent weeks regarding Shell South Africa’s proposed drilling for Natural Gas over vast tracts of the Karoo.


Bonang Mohale, Country Chairman of Shell South Africa (“Shell”) opens up his statement in a full page advertisement, which appeared in local newspapers during mid-March, with the line “The Karoo is a special place for South Africans. We must preserve it for our future and our children’s future”.


A dichotomy if there ever was one!


 

Picture : IVOR MARKMAN / The Herald



For those readers who don’t know the background to this story; Shell wish to explore for Natural Gas and in the process intend drilling 24 deep wells over large areas of the Karoo between Middelburg, Graaf Reinet, Aberdeen and Beaufort West.


The wells that Shell hope to drill are going to be deep holes that will penetrate the shales of the Lower Beaufort Formation and huge volumes of chemical-impregnated water will be pumped into the strata, under high pressure, thereby fracturing the carbonaceous shales and consequently releasing the entrapped gas; a method known as fracking.


This is all good and well in theory but there are bound to be negative impacts: I will touch on two important ones.  The ‘poisoned’ water that will be pumped down the holes will contaminate the Karoo’s scarce potable water. Shell maintain that the fracking water will be pumped well below the average depth of Karoo water aquifers and therefore won’t mix with underground water sources. This is a naive assumption because Shell geologists should know that there are numerous springs in the Karoo. Where do they think these springs originate?   Take for example the Brandvlei Hot Spring whose water temperature is 64 degrees C. Since groundwater is heated by the earth’s geothermal gradient (it gets hotter with depth) at a rate of 25 degrees per 1000m depth that would put Brandvlei’s source at a depth of at least 3 km. So, no matter how deep Shell intend drilling, the Karoo’s water table will become polluted. The rocks below will be like shattered glass and all the fractures eventually lead into each other.


There is also the problem of interfering with radioactive minerals in adjacent strata.  The Karoo Uranium rush of the 70’s and 80’s (in which I was involved as a geologist) uncovered substantial uranium mineralisation also in the Lower Beaufort Formation. Some of the minerals are quite soluble and could be leached out by percolating fluids from the fracking process thereby further contaminating valuable water sources. Should such an eventuality ever occur the water source would be rendered useless for eons to come since uranium has a half life of billions of years ie it hangs around forever!


So Shell, please think of the possible life-threatening impacts in the Karoo and stick to your promise of preserving that beautiful area “..for our future and our children’s future”


Think twice before you drill.


Article : DR NICK STAVRAKIS (PhD Geology, Pr. Sci Nat)

Originally published in the Herald


Picture : IVOR MARKMAN / The Herald


Nick is a business consultant, providing advisory consulting services to Aquasolar.  After a successful career in the mining and energy industries, including the establishment of three companies listed on the JSE, Nick is semi-retired and consults to Aquasolar on strategic topics such as environmental, technical and economic matters.


Thursday, March 24th, 2011 - News

 
   
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