Rosalind Todhunter 01 Dec 2017
Have you been watching Channel 5 Sinkholes programmes?
http://www.channel5.com/show/sinkholes/
https://twitter.com/hashtag/sinkhole
What about the salt sinkholes in Cheshire?
We know they are there. But not always where.
Northwich the town that survived mega sink holes.
https://twitter.com/lionsaltworks
Would you build a high speed rail line through mid-Cheshire sinkhole centre of the UK?
https://twitter.com/mcahs2
What does HS2 think about sinkholes in Cheshire?
https://twitter.com/hashtag/hs2
Did HS2 Know About Sinkholes In The Open Flat Landscape Of Cheshire Plain?
In July 2013, HS2 stated the preferred’ high speed rail route is: ‘between Winsford and Middlewich across the open flat landscape of the Cheshire Plain’
http://assets.hs2.org.uk/sites/default/files/consultation_library/pdf/P2C04%20Non%20Technical%20Summary.pdf Item 7.2.1
Under the ‘open flat landscape of the Cheshire Plain’ is a great spread of sinkholes, underground brine runs that stretch for miles around, between and beneath the salt mining and salt brine pumping towns of mid-Cheshire’s salt district – Northwich, Middlewich and Winsford.
Here there’s has been over 2000 years of continuous salt industry; brine springs, brine wells, brine pumping, underground salt mining, solution salt mining. And lots of ground collapse – sinkholes.
What Did HS2 Miss?
Miles of active sinkholes of known and of ‘known-unknown’ size and depth
One active rock salt mine just a few tens of metres below the ground surface
170 + active salt solution mining brine wells each with a salt cavity that could accommodate St
Pauls or Blackpool Tower (choice of size comparator depends on whether you live north or south of
Watford)
20 giant gas storage salt cavities with many more planned. (Also each cavity can hold St
Pauls/Blackpool Tower). These are part of the UK’s strategic gas reserve. We only have a few weeks
gas in store before the lights would go out if power stations were switched off due to increase in
demand from severe cold weather or our gas imports from the Middle East and Norwegian gas
fields were stopped or sold elsewhere
And 2000 years of continuous industrial salt mining, brining and solution that is still very actively
supplying the UK’s chemical industry in Cheshire and Merseyside now and into the future
The ‘Known-Unknown’ Sinkholes And Brine Runs Of Cheshire.
We Know They Are There. But Not Always Where.
We know there are sinkholes in mid-Cheshire’s salt district, in and around the salt towns of Northwich,
Middlewich and Winsford.
But we don’t know where all the sinkholes are. What shape are the sinkholes?
How deep are the sinkholes? Where and when will the next sinkhole appear?
Sinkholes form above underground brine runs – flowing water below the ground surface that dissolves the
rock salt creating holes and cavities. Then the ground above sinks and collapses.
There’s no underground mine plan records for brine runs. Brine runs can be miles away from where brine
wells were pumping or where brine issues from a natural brine spring. Brine runs are both natural features
and a consequence of un-controlled and un-recordable salt solution mining/brining.
Its only when sinkholes form at the surface then we know there’s a brine run.
But the brine run depth, shape and extent is still a ‘known-unknown.’
Northwich the Town That Survived Mega Sinkholes
The salt town of Northwich is riddled with and surrounded by sinkholes and flooded old rock salt mines.
2000 years of continuous salt extraction, brining and mining have left their mark. Visit the Lion Salt Works
with displays and info charting this amazing industrial heritage. Past, present and future.
http://lionsaltworks.westcheshiremuseums.co.uk/
In the 1880s and early 1900s Northwich was sinking due to salt mining and brining and it took until the 21st
century to sort it all out. The town centre collapses have now been stopped by almost 3 years of pumping
salt saturated grout into four flooded and unstable salt mines. Northwich town centre is safe and stable
with a brand new shopping centre built over the grout filled mines just awaiting commercial tenants.
But there still remains many more flooded and unstable salt mines just on the edge of town under
Neumann’s and Ashton’s Flashes (flooded sinkholes).
http://www.ukqaa.org.uk/wp-content/uploads/2014/02/Case_Study_11_May_2007.pdf
Are the Flashes in Northwich the Biggest Sinkholes in UK?
Northwich’s Catastrophic Collapse And Enormous Sinkholes
Over 100 years ago catastrophic collapse and enormous sinkholes were created as the rock salt mines
flooded with water. For Northwich it was as if the end of the world had come.
The fresh water in the flooded rock salt mine dissolved the salt mine walls and salt mine roofs. The mines
kept collapsing, more sinkholes formed, rivers flowed backwards into the rock salt mines, more salt
dissolved, the sinkholes grew bigger and bigger, buildings were swallowed, main roads lost, canal
collapsed. The sinkholes flooded to form ’flashes’.
But why miss this new economic opportunity? Why not exploit the flooded salt mines?
Shafts were sunk into the flooded mines and brine from the mines was pumped and given its own
distinctive name ’Bastard Brine’.
As the brine was pumped out fresh water came in and more salt dissolved and more sinkholes started
appearing around the flooded mines of Northwich. And all around Northwich. Even miles away linear
sinkholes formed over underground brine runs linked over great distances from where the brine pumping
was taking place.
‘Bastard Brine’ pumping has now ceased, brine pumping is now controlled and the one remaining active
shallow underground rock salt mine between Winsford and Middlewich, and under the HS2 route, is kept
water free.
http://cheshirerigs.org.uk/wp-content/uploads/2017/06/24-June-2017-Geological-Resources-Saltsape-
Lecture.pdf
And Would You Build A High Speed Rail Line Through Mid-Cheshire, The
Sinkhole Centre Of The UK?
Brine runs and the sinkholes are still active all over mid Cheshire. The ground is still on the move. Sinkholes
are still there and brine runs with underground salt cavities of ‘known-unknown’ size, depth and location
are scattered throughout the ‘open flat landscape of the Cheshire Plain’ between the salt towns of
Northwich, Winsford and Middlewich directly under the chosen path of the HS2 high speed rail route.
