# Llanberis RAF Reserve Depot (Bomb Store) - 09/10



## bungle666 (Sep 30, 2010)

Visited with Mortaldecay.

On 18th August 1939, the Air Ministry sought approval to acquire the disused Glynrhonwy Isaf slate quarry which had closed in 1930; the quarry, near Llanberis in North Wales, was deemed suitable for the storage of 18,000 tons of bombs. It consisted of a number of deep open pits, linked together by tunnels. Following the apparent success of the design employed at Harpur Hill in Derbyshire, the air ministry decided to use the same technique at Llanberis, converting the eastern pit into an underground depot, but because of the great depth of the quarry the design was adapted to produce a structure with two floors throughout. The lower level and a conventional flat reinforced concrete ceiling which also formed the floor of the upper level which had an arched roof like that at Harpur Hill. Standard and narrow gauge railway lines entered the lower level of the depot through the original quarry access tunnels, while three electric lifts transported bombs to the upper floor. The deep pits to the west of the depot were later used for burning and dumping redundant and dismantled ordnance.







Overhead protection was given by forty feet of broken slate. In response to pressure from the treasury efforts were made to cheapen and accelerate the construction of Llanberis, but unfortunately the cost cutting had disastrous consequences only six months after the depot was opened. 

On 25th January 1942, two-thirds of the structure collapsed within seconds under the weight of the overlaying backfill, completely engulfing a train of twenty seven wagons which was in the process of unloading. The collapse buried over 14,000 tons of bombs which at the time represented 14% of the total RAF stock. A court of inquiry concluded that faulty design was the principal cause of the failure; cracks were noticed in the structure as the building neared completion but these were attributed to minor defects rather than to a major and fatal miscalculation. Most of the bombs were recovered and although the remaining tunnels were eventually cleared of debris, no ammunition was ever stored underground at Llanberis again. The surviving underground galleries were abandoned and the collapsed section was used for open storage of incendiaries and as a demolition area with ordnance being dumped in the pits to the rear of the depot.

The depot remained in use after the war but all functional stock was removed by March 1955 and the depot closed in July 1956. 

We visited on a slightly damp (as is so often the case in snowdonia) Thursday afternoon. access was a doddle and it made for a chilled couple of hours.

this is where the trains would have entered the store.






Big and very empty spaces is the order of the day.






Post collapse some of the internal arches were strengthened with bricks to shore up the rest of the structure.. 






and some were left as built..






lift..






Stairs..






The train now arriving at....






Hang on... whats in here?






possibly the highlight of the place, thats what!! the escape/air/service tunnel at the back of the store!!











collapse at the bottom of the shaft






All in all a superb day!

B..


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## fluffy5518 (Sep 30, 2010)

BUNGLE !! What a cracker,have been attempting a trip up here for a while now but its a long way from Didcot !! A real top notch report mate with some excellent piccies as well.You're right about the highlight of the trip that escape passage is great.It doesn't seem as chavved as i was expecting either !! One day perhaps,one day !!


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## klempner69 (Sep 30, 2010)

Cracking report Bungle and well shot too


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## The Cat Crept In (Sep 30, 2010)

A great place to visit did this one about a year ago still looks very impressive well done


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## Tomoco (Sep 30, 2010)

Great job mate, nice shots.


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## bungle666 (Sep 30, 2010)

fluffy5518 said:


> BUNGLE !! What a cracker,have been attempting a trip up here for a while now but its a long way from Didcot !! A real top notch report mate with some excellent piccies as well.You're right about the highlight of the trip that escape passage is great.It doesn't seem as chavved as i was expecting either !! One day perhaps,one day !!




It wouldn't be worth a trip on its own TBH. Although if you combined it with a trip up to australia level in the old dinorwic quarries across the valley it would make an epic day out!!

B..


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## fluffy5518 (Sep 30, 2010)

Yeah !! Thats exactly what i had in mind,all i've got to do now is to convince mrs fluffy that North Wales is a particularly good place to visit at half term !!!(.....and no,she isn't under 18 !!!)
WISH ME LUCK !!!!!


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## lost (Oct 1, 2010)

Nice job bungle!!! You make it look quite appealing. 
Last time I was there we had a quick look and it was quite well sealed - I guess it's easy enough to access with a bit more enthusiasm.


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## professor frink (Oct 1, 2010)

Nice work, this looks better than I would of ever imagined.


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## AndyC (Oct 1, 2010)

Very interesting place.

Couple of things:

Your Fourth picture looks as if it was a long exposure using an existing light. How did you do that? Clever placing of the flash?

Also I am sure the white painting on the floor where the tunnel begins (where the stream passes under) is very recent - I was there at the end of August and do not recall it.

Llanberis and the area is very interesting. On the other side of the valley is the remains of Dinorwic Slate Quarry - fascinating and has been reported on the site before.

And when you get peckish get thee to Pete's Eat's in the village. Their Chip Butties and big mugs of tea are legendary.


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## bungle666 (Oct 1, 2010)

AndyC said:


> Very interesting place.
> 
> Couple of things:
> 
> Your Fourth picture looks as if it was a long exposure using an existing light. How did you do that? Clever placing of the flash?.



just a 120 lumen LED converted 3D maglite placed in a strategic position 



AndyC said:


> Llanberis and the area is very interesting. On the other side of the valley is the remains of Dinorwic Slate Quarry - fascinating and has been reported on the site before.



been there and done that last December.... there is a report knocking around somewhere online....


B..


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## nij4829 (Oct 1, 2010)

what a place. thank you for sharing.

i, like many people have had this on my radar for a while but need to find more places to visit in the area to make a 'weekend' of it.


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