A water-drilling team contracted by the metro came agonisingly close to a mega-strike at Coega on Wednesday.
It is anticipated that the flow from the new Coega artesian well could deliver 150l of water a second – meaning 540m³ an hour or 13,000m³ a day, hydrogeologist Dr Ricky Murray said.
“It’s huge – potentially the biggest yield in Southern Africa and probably in Africa and most parts of the world.
“The whole Coega Industrial Development Zone doesn’t even require half that volume. “We’re very excited,” he said. The monster well is the culmination of extensive work by Murray and geologist Marc Goedhart, who were convinced that the groundwater yield in the area could be substantially improved from the accepted 2.5m-5m a second.

Metro water and sanitation director Barry Martin said a treatment plant was being built at Coega and the water from the new well and four others sunk in the area would be channelled through this plant once it was completed in two years’ time.
“From there, it will go to the Coega Kop Reservoir to be distributed to Motherwell and the Coega Industrial Development Zone.
“Together these wells should cover 5%-10% of the metro’s total water needs, which is substantial when you consider they will not be influenced by rainfall.”
In 2010, the Nelson Mandela Bay municipality contracted Aurecon to look into extra water-supply solutions and the company sub-contracted Murray, who then brought on Goedhart.
They started by relooking at the oil exploration maps of the Uitenhage Artesian Basin compiled in the 1970s by the then Southern Oil Exploration Corporation (Soekor).
The aquifer comprised ancient water that had seeped down from the Grootwinterhoekberge northwest of Uitenhage, Murray said.
“We know from studies done that this seepage travels at 1m per year so it took 20,000 years to get here.
“With this well, we will be intercepting a portion of the aquifer before it flows into Algoa Bay.
“Once the well is established, I will do a yield assessment to see how much we can extract without jeopardising the long-term flow.
“We will not simply mine it. “One of the great benefits is how cheap this water will be compared to desalination, for instance.”
The Soekor study area which they were interested in comprised a layer of young rock on top of a 500-millionyear-old layer of Table Mountain quartzite, he said.
“About 90-million years ago, tectonic forces associated with the fracturing of Gondwana ripped through this quartz layer forming what we know today as the Coega Fault.”
With the help of University of Witwatersrand geologist Prof Edgar Stettler, Murray and Goedhart interrogated the Soekor data further and narrowed their focus to an area west of Coega Kop where the quartzite rose relatively close to the surface.
The area was once covered by the sea and Coega Kop was an island like present-day Jahleel and St Croix islands.
Today, millenia later, located on the eastern rim of Motherwell, the challenge was to find this fault, Murray said.
“We knew it was lying at a near-vertical angle 200m underground.
“It was like looking for a needle in a haystack.”
The different kinds of rock in the area had different densities, however, so through the use of a gravimeter they pinpointed where the quartz rose closest to the surface.
The earth’s crust was constantly charged by lightning strikes and different rocks had different electric conductivity capabilities, he said.
“So we used a magnetelluric machine which measured the different conductivities, mudstone being much more conductive than quartzite, and that allowed us to close in on our target.” With the final resistivity survey, they created their own lightning strikes to check the conductivity capability of the different rock layers, but before they could do so, they had to get the local electrical supply switched off, otherwise they would interfere with the instrument.
“We eventually reached an agreement that they would be off for six hours, which was not really long enough, but it was all we could get,” Murray said.
Developed by a Johannesburg-based company, the resistivity instrument was being used in South America and they had to wait until it became available.
It eventually arrived, and they were all set to go...