Report - - Quarry Dean Firestone Mine, Merstham, Surrey - June 2020 | Mines and Quarries | 28DaysLater.co.uk

Report - Quarry Dean Firestone Mine, Merstham, Surrey - June 2020


Sauter Les Frontières
28DL Full Member
The Quarry Dean firestone mine in Merstham, Surrey, is just one of the many mines, stone quarries and underground workings that are scattered along the North Downs between East Kent and Surrey, and is also by far one of the oldest.
This particular underground stone quarry dates back as far as Roman times, as a section of it bears Roman characteristics in its stone brick lining. However, no record of its existence came to light until 1522 when it was mentioned in a reference to the nearby Quarrepitden farmhouse.
Interestingly, it was from this mine and others nearby that much of the stone used for building London in medieval times were quarried from. The stone itself is a calcareous sandstone, which is found in a layer up to 40' thick at Quarry Dean area, which provided the perfect material for construction.

The majority of underground workings are found in the Lower Greensand areas


The stone that was extracted varied in quality, and it was known as 'Firestone', which is the same material that many of the canal basins and bridges were built out of during the industrial revolution in the late 1700s/ early 1800s.
As these mines were dug, the quarrymen left pillars of rock to support the roof, a technique that was known as 'pillar and stall', however, over time, many of the pillars have collapsed, and have since aged into the rocks surrounding them, giving the mine a look that's considerably closer to that of a natural cave rather than a manmade working.
Quarry Dean remained operational up until the end of the 17th century, however, like all other nearby underground stone workings, it was forced to close, and subsequently had all its entrances filled in. Fortunately, the mine was re-excavated by a Mr Harrison who farmed at Quarry Dean in the 1960s and has since remained unfilled :))

The Explore:
After having driven over to Surrey with my mate @james nichols, we briefly met up with @R_yoda to borrow some much needed abseiling gear (cheers once again mate!) and set off in the direction of the entrance. Once we'd worked out how half of the equipment we borrowed actually worked, we began to descend into one of Surrey's oldest underground quarries, and almost instantly, we realised we weren't in Kent anymore...
With both our senses of direction not being exactly the most reliable, we left small piles of white shingle in our wake, just In case we took a wrong turn. However, it soon became obvious we'd overestimated the size and intricacy of the mine, as I found myself able to retrace our steps without the aid of the shingle.
Having reached the 2 underground lakes, we decided to stop for 5 minutes to take it in, as I'd not seen anything quite like it since visiting the Palvolgyi Caves in Budapest back in 2017. Then so, after snapping some very needed shots of the lakes, we pressed on further, unbeknownst to us that this was where things were about to get a little more... damp.
I'm not sure whether these mines are always like this, but the floor was a little more than tacky in quite a few places, almost turning into a clay-like terrain in places, definitely something I wasn't sad to see behind.
Having reached as far as we could go, and encountering the odd bat or 2 flitting about along the way, we decided to head back, and ascend into the much appreciated warm air above. All in all, this was certainly a place I won't be forgetting in a hurry.

1. The Underground Lake


2. Example of a pillar & stall wall


3. An original chain can still be seen


4. The claustrophobia begins


5. Getting somewhat tacky


6. One of the splits in the network


7. More pillar & stall


8. Underground puddle (think I preferred the lake)


9. One last backlit shot


10. One of the squeezes (I try to keep my face off public reports)


- Thanks for looking -

Last edited:


Rum Swigger
Regular User
We went for a look at it mate yes, but sadly they’ve covered the entrance with earth and all sorts from what we saw, bit annoying that :/
Shame,locals were probably worried about kids going down there.......it used to be laddered

it’s not as nice as quarry dean......much more messy

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