This week we have a guest blog from Neala, one of our brilliant Archives volunteers here at Manchester Central Library who tells us about a recent staff visit to our offsite archives storage facility in Cheshire. Our thanks go to Omar and his fantastic DeepStore team who looked after our staff so well.
I have been volunteering for the past two years for an Archives photograph project digitising images for the Manchester Local Images website Home – Manchester Images. As part of my work with the archive team at Manchester Central Library, an opportunity arose to visit DeepStore storage facility used for preserving our archives. I jumped at the chance.
We set off on an unusually warm sunny day in April, from Central Library travelling through the Cheshire countryside to the salt mine in Winsford, the location of the storage. On arrival we were welcomed by Omar who gave us a brief history of the rock salt mining, DeepStore and a health and safety briefing which included the required equipment and clothing worn by all visitors
The history of mining at Meadow Bank / Winsford rock salt mine mine
Mining began at Winsford in1844. Rock salt was accidentally discovered when prospectors were searching for coal. Between 1844 and 1892, 1 million tonnes of rock salt was mined during this period. The mine was forced to close in 1892 due to oversupply and competition but was re-opened in 1928 due to the flooding of the neighbouring mines in Northwich which, ironically, were the same mines which led to the closure in1892. Today, 1 million tonnes of rock salt is mined at Winsford, per year and it supplies 90% of rock salt used to grit our icy roads in the winter. It is the oldest and largest working rock salt mine in the UK with an area of approximately 700 football pitches, stretching to 100 miles of tunnels.
DeepStore
DeepStore moved into the spaces carved by mining millions of tonnes of salt in 1998. It provides specialist storage facilities for archives, artefacts, records, documents, archaeological objects including bones and even private art collections. It is the UK’s largest underground document storage. Storage is located about a mile or so away from active mining so there is absolutely no danger of any damage occurring, just in case you were considering storing your collections there!
Omar’s colleague, Will joined our group to ensure our safety and to answer the many questions we had. Before we were able to venture underground we were provided with hard hats with, high vis jackets and emergency breathing apparatus which would provide us with 45 minutes oxygen if there was an unlikely explosion and we were at the furthest point from the lift. We went through security and all kinds of other checks before we stepped into the lift. Access is strictly controlled, monitored by CCTV, intruder alarms as well as GPS tracking on all vehicles. You may be wondering why a salt mine for the storage of archives, documents, artefacts and even paintings? The salt caverns maintain a constant natural temperature of roughly 15 degrees Celsius, with low humidity – both optimal conditions for the preservation of records, artefacts and even bones. The National Archives is one of DeepStores most prominent clients, housing a significant proportion of its extensive collection here. Other clients include Manchester Archives, Buxton Museum and Art Gallery, Oldham Local Studies and Archives, Royal Horticultural Society. John Rylands Library is one of the clients used as a case study on DeepStore’s website https://www.deepstore.com/resources/case-studies/case-study-john-rylands-research-institute-library/
Descending 150m below ground in a metal box where all trust was placed in mechanics and engineering could have resulted in a few panicked moments but we all managed to remain calm. I kept my eye on the digital reader which showed how many metres below ground we were – this helped me focus on the end, minus number.
With some relief, we were now at -150m. I had never been so far below sea level, it was difficult to comprehend, the layers of rock, millions of years old above us. Will opened the lift doors, we stepped out into a vast subterranean space – quiet, still, and awe inspiringly expansive, with long, cathedral-like tunnels all carved from mining salt. It took me a few minutes to take in the scale of it all. I have been in caves before but nothing prepared me for the space which opened out in front of us.
The actual spaces used for storage opened out from doors in walls, created to IKEA warehouse like proportions filled from the ground to the ceiling, space after space of collections, boxed or wrapped by the qualified heritage team who specialise in the handling of rare fragile materials. Unfortunately, due to confidentiality, visitors are requested not to take photos whilst in these storage spaces.
After an hour of seeing what was probably only a small sample of the storage areas and asking Omar and Will lots of questions, it was time to head to the lift for our 150m ascent and back into the welcome sunshine and the realisation that working underground with no natural light and greenery would not be a place for me. We were grateful to be in the sunshine and have lunch provided by DeepStore. Delicious sandwiches, drinks and even cakes. We were spoilt.
A great way to end a fascinating visit. I am grateful for the opportunity as a volunteer to have been offered a place on this visit. It will be an experience I will remember and continue to share.
What makes Winsford so remarkable is not just its scale, but its purpose. The natural environment deep within the mine provides exceptionally stable conditions—low humidity, consistent temperature, and protection from light, flooding, vermin and pollutants. These qualities make it an ideal home for preserving historical records and archives, safeguarding them for generations to come.
Seeing this hidden infrastructure firsthand was a powerful reminder that preserving history is not only about collecting stories, but also about protecting them with care and foresight. Facilities like the Winsford underground store play a vital, often unseen, unknown role in ensuring our shared heritage remains accessible, secure, and intact well into the future.
