In 2003, the National Archives moved about 25km of records to a salt mine in Cheshire.
“It was a necessity for us,” says Tom Gregan, the head of document services at the National Archives.
The archive had been sharing storage space with a number of other government departments but this wasn’t providing the adequate environmental standards it required.
Gregan and his team looked at a number of options for housing the growing collection of records, and opted to relocate items to a salt mine run by DeepStore.
The company’s storage facility is located in Winsford and fills the void left by the millions of tonnes of salt that were removed by Compass Minerals, the UK’s oldest working mine.
The fact that the mine is still in operation, and therefore subject to regular inspections, was one of the attractions for the National Archives.
The mine meets the specifications of British Standard PD5454, and Gregan says it fulfilled all of the organisation’s preservation needs: “We’re confident that it provides perfect – and consistent – humidity and temperature, and there is no threat from vermin or insects as they can’t survive down there. It also offers very high levels of security.”
Gregan says that going with a third-party supplier was also felt to be the most cost effective option for the National Archives.
A number of consultants were hired to investigate whether a salt mine was the right place to store records, many of which date back nearly 1,000 years, ahead of the relocation in 2003.
Photographs and film footage are not currently in the store, but Gregan believes the storage of such items would be possible despite the salty atmosphere.
“Everything is boxed and sealed before it goes down into the mine, and nothing is ever opened underground. So as long as items were boxed properly, I think we could store film, for example, down there.”
The National Archive’s contract with DeepStore allows it to retrieve items using a specially-created document ordering system for record management and retrieval. It normally takes about 24 hours for a requested item to reach its base in Kew, south London.
Of the 600,000 retrieval requests the archive receives each year, it aims for less than 1% of these to come from the salt mine.
Gregan is relieved that the number of requests is nowhere near that level. The reason for this is that National Archives only stores rarely or never-used objects in Cheshire.
“Ironically some of the items at DeepStore are among our most popular requests,” says Gregan. “But these have all been digitised, so the originals can be stored away.”
For example, the archive’s large volume of first world war records are all stored in the mine, including regimental and individual service records, medical records and medal award index cards and associated files.
Copies of original letters to families and loved ones from soldiers serving on the frontline are also held at DeepStore.
During the first world war centenary these items have been popular with researchers and members of the public, but the majority of the records can be viewed in in digital format on the National Archives’ website.
The National Archives takes about 1km of records from the government every year. Its store in Kew is full, so it needs to move records into deep storage at the same level. For that reason, the archive’s digitisation programme has to be maintained going forward.
After more than a decade of using DeepStore, Gregan says he is pleased with the way the relationship has worked. But he says that opting for a third-party storage solution isn’t without its risks.
Staff from the National Archive visit Cheshire on a monthly basis to inspect the mines, and the contract with DeepStore is regularly reviewed.
“It’s very important to have control when you store items off site,” Gregan says. ““The ‘attic approach’ – where items are put into any type of storage and just left there – is a big error.”
Tom Gregan will present a paper on deep storage at the forthcoming MP seminar, Off The Shelf: Making Storage Work For You, at the British Museum on 17 March
“It was a necessity for us,” says Tom Gregan, the head of document services at the National Archives.
The archive had been sharing storage space with a number of other government departments but this wasn’t providing the adequate environmental standards it required.
Gregan and his team looked at a number of options for housing the growing collection of records, and opted to relocate items to a salt mine run by DeepStore.
The company’s storage facility is located in Winsford and fills the void left by the millions of tonnes of salt that were removed by Compass Minerals, the UK’s oldest working mine.
The fact that the mine is still in operation, and therefore subject to regular inspections, was one of the attractions for the National Archives.
The mine meets the specifications of British Standard PD5454, and Gregan says it fulfilled all of the organisation’s preservation needs: “We’re confident that it provides perfect – and consistent – humidity and temperature, and there is no threat from vermin or insects as they can’t survive down there. It also offers very high levels of security.”
Gregan says that going with a third-party supplier was also felt to be the most cost effective option for the National Archives.
A number of consultants were hired to investigate whether a salt mine was the right place to store records, many of which date back nearly 1,000 years, ahead of the relocation in 2003.
Photographs and film footage are not currently in the store, but Gregan believes the storage of such items would be possible despite the salty atmosphere.
“Everything is boxed and sealed before it goes down into the mine, and nothing is ever opened underground. So as long as items were boxed properly, I think we could store film, for example, down there.”
The National Archive’s contract with DeepStore allows it to retrieve items using a specially-created document ordering system for record management and retrieval. It normally takes about 24 hours for a requested item to reach its base in Kew, south London.
Of the 600,000 retrieval requests the archive receives each year, it aims for less than 1% of these to come from the salt mine.
Gregan is relieved that the number of requests is nowhere near that level. The reason for this is that National Archives only stores rarely or never-used objects in Cheshire.
“Ironically some of the items at DeepStore are among our most popular requests,” says Gregan. “But these have all been digitised, so the originals can be stored away.”
For example, the archive’s large volume of first world war records are all stored in the mine, including regimental and individual service records, medical records and medal award index cards and associated files.
Copies of original letters to families and loved ones from soldiers serving on the frontline are also held at DeepStore.
During the first world war centenary these items have been popular with researchers and members of the public, but the majority of the records can be viewed in in digital format on the National Archives’ website.
The National Archives takes about 1km of records from the government every year. Its store in Kew is full, so it needs to move records into deep storage at the same level. For that reason, the archive’s digitisation programme has to be maintained going forward.
After more than a decade of using DeepStore, Gregan says he is pleased with the way the relationship has worked. But he says that opting for a third-party storage solution isn’t without its risks.
Staff from the National Archive visit Cheshire on a monthly basis to inspect the mines, and the contract with DeepStore is regularly reviewed.
“It’s very important to have control when you store items off site,” Gregan says. ““The ‘attic approach’ – where items are put into any type of storage and just left there – is a big error.”
Tom Gregan will present a paper on deep storage at the forthcoming MP seminar, Off The Shelf: Making Storage Work For You, at the British Museum on 17 March