Second thoughts...if it's right on the beach at Maenporth it's not the Swanvale outfall, that's further around the headland towards Swanpool, although the minging black water does look sewagey. There is a sewage pumping station at Maenporth with an overflow but I can't believe they'd have built an adit for something that small.

I'm still working with SWW, (not for them any more) so next week I'll check the sewer maps for anything in the area.

Thanks for the info fearnside, I had a quick look into this again late October last year, though did not venture far in as had no gear with me.

Water seems to flow out of this adit at a constant rate and of course backs up when the tide comes in, the water looks clean with no suds or anything being carried along.

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I think you're spot on fearnside, that tunnel was driven in the mid fifties I think by Falmouth Town council for the very reason you stated.
At the risk of telling anyone how to suck eggs. Care must be taken as to which way the tide is running, as at the Swanpool end there is a securely locked steel door and the only way out is to retrace ones steps. This could involve a very long wait if the tide is in.

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Sewer outfalls dumping turds on the beaches, ha ha yes. A very jolly 60s and 70s practice, now thankfully discontinued.

Whitby recently acquired a new sewer outfall to deal with this problem, along with quite a few other resort towns over the past 30 years or so.


the sewage contains high levels of organics and the resulting sediment is very nasty stuff. I would avoid it completely, along with any tunnel believed to have such a history :blink:

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I wondered about the swanpool steel door (which incidentally isn't locked) went back with a torch, it stunk. The End.

There are some adity things around there, but they are beyond the scope of this thread. 🙂

I wondered about the swanpool steel door (which incidentally isn't locked) went back with a torch, it stunk. The End.

There are some adity things around there, but they are beyond the scope of this thread. :)

Surely it would be safer and wiser to assume that it is locked?

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Second thoughts...if it's right on the beach at Maenporth it's not the Swanvale outfall, that's further around the headland towards Swanpool, although the minging black water does look sewagey. There is a sewage pumping station at Maenporth with an overflow but I can't believe they'd have built an adit for something that small.

So going right back to the origins of the thread... is this the water outlet tunnel the one right next to the beach at Maenporth or the Swanvale sewage outlet which is around the headland towards Swanpool???
The Swanvale outlet is quite a long way from Maenporth isn't it?

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I lived near Swanpool about 60 years ago; here's my two pennyworth, from a fallible memory.

In the mid 1950s a sewer outfall was dug from a heading just to the west of the public toilets at Swanpool beach at about 180162,31220 pretty well south under the coastal path to an outfall on Pennance Point at about 180442,30552. The path was widened and there was an access shaft for removing spoil at about 180294,30717. The manhole was originally about a foot above the level of the footpath and on the inland side of it. I don't know where the spoil went, it wasn't tipped over the cliff above the little beach, which was then called Sunny Cove, though I see the Ordnance Survey call Newporth beach Sunny Cove. I believed as a child that there was a pump house in the heading.

Quite separately there was also the remains of a cut and cover arched horizontal tunnel about 3 feet wide and 4 high from about 180357,30667, a little below the path, which ended at about 180326,30604 where there were the remains of a brick chimney. In fact the whole area was called "The Stack"
I believed that this was a horizontal chimney used for harvesting condensed arsenic from the mine processing buildings at about 180199,30964 .These buildings were stone, don’t be misled by the bricks on the foreshore from a house which fell down the cliff.

As to the Maenporth adit, I never ventured in as an infant, I assumed it was a drain for the lagoon to the north of the beach, which used to be bigger. A pleasing symmetry with Swanpool.

Am I looking at the wrong place or should those NGRs starting with 180 be 801?

I think you are right; should be 801. The GR for Swanpool Mine is SW801312.

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Sorry all, I pasted them out of Streetmap, :oops: and I didn't translate them to traditional grid refs. They do work in Streetmap though.
I did check that. :thumbup:

It's rude to reply to myself, but... after a quick zoom about Streetmap, the first digit seems to be 100km squares, and the origin is WSW of the Scillies. I prefer the letters myself.

Interesting to read people's experiences about going up the Swanvale tunnel...sorry to hear it stank though, I'd always fancied a look down it but not sure I'll do it now.

Anyway I've checked the sewer maps. If it's right on Maenporth beach, there's no record of anything seweragey. Someone did have a vague memory of there being a system to drain the lagoon behind the beach, probably in the care of the Environment Agency...so I reckon Underwhere's hit the nail on the head.

As a matter of interest, I'm visiting Falmouth in a week or so and there's a cave between Swanpool and Gyllyngvase with a mysterious iron door at the back. Has anyone ever stuck their head in there? I always wondered what it was (possibly some old SWW tanks but I'm hoping not).

I remember I took a photo of a sign outside the adit whilst on Holiday there last Oct 2009. Here it is.

🔗Personal-Album-347-Image-48169[linkphoto]Personal-Album-347-Image-48169[/linkphoto][/link]

Anyone know what the letters stand for?

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Anyway I've checked the sewer maps. If it's right on Maenporth beach, there's no record of anything seweragey. Someone did have a vague memory of there being a system to drain the lagoon behind the beach, probably in the care of the Environment Agency...so I reckon Underwhere's hit the nail on the head.

The tunnel heads in the opposite direction from the lagoon over the road by the beach.

I dare say there's only one way to find out, any of you Cornish lads got a wetsuit?

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Hi
Hopefully I can shed a bit of light on the tunnel at maenporth beach in south Cornwall.
I’m a keen caver and due to the lack of limestone in Cornwall I moved onto exploring mines.

When I was a student studying at Falmouth marine school I came across the cave entrance at maenporth.

I now know the tunnel links between the beach and the tidal pond to the rear of the beach emptying and filling depending on different states of the tide.

The tunnel is not to be attempted by the fait hearted! I’m pretty hardy when it comes to small places with limited headroom and breathing space and deep cold water but nothing prepared me for the size of the crabs in their, THEY ARE BIG SERIOUSLY BIG!

The tunnel first starts at the beach and makes it way towards the house above.

At this point the tunnel is quite wide 2.5ft and 5ft tall with about 6 inches of water gradually getting deeper

As you go further in there is a side adit that goes to the left it looks to have been filled in with rocks.

Further on the water begins to deepen and the velocity decreases.

On from there the water is now about 2.5 feet deep. There are a number of concrete ring beams and blocks down the sides of the tunnel. About 10ft further on an archway reduces the headroom considerably to just over a foot. And 1.5ft wide

Where the concrete blocks end and the picked passage continues the water is now 3-3.5ft deep with 10 inches of headroom.

The lowest part of the passage is 20ft on from here the headroom goes down to about 6 inches if you turn your head sideways you can get away with water going down the collar of your wetsuit. Once you’re past this the passage starts to re gain head room.

Now a brick arch passage continues for a further 20ft to the chamber or base of shaft.

In the picture with the glowing seaweed you enter the base of a shaft this is the worst bit!
The shaft is 20ft high 8ft in diameter with a cap on the top. The water is about 5ft deep and the floor is moving! The floor of the shaft is alive with crabs and there all moving on top of each other it’s a horrible feeling in wetsuit boots!

Past that you come to a rusty iron gate on the left of the shaft. The bars have rusted through so carefully step through. The passage is much wider with light at the end. The passage continues for a further 40ft and comes out in the tidal pond at the rear of the beach.

http://www.flickr.com/photos/76356248@N08/6848153517/in/set-72157629249300417/ 

copy link to the browser for the photo's.
Click on mine photo's in order to start at the Beginning.

At High tide the mine is totally submerged. It is very easy to loose your footing due to the volume of water moving and the moving rocks (crabs) on the floor of the tunnel.

The purpose of all these tunnels was almost certainly the same as that at Loe Bar, to prevent flooding back up the valley at times of high river flow/spring tides/storm surges etc. When that at the Loe became blocked it resulted in flooding in the lower parts of Helston.
In the Swanpool area, I have made a few attempts to find some adits described in an article published by the Royal Cornwall Polytechnic Society (don't have the details to hand, but this is by far the best account of mining in the area, late 19thC possibly written by Stephens). These appear to have been between Swanpool & the next headland to the south. Couldn't find anything & thought they may have been lost under a cliff fall, although there were some ochrey seepages in places.
This New Year went to Sunny Cove which is round the headland towards Maenporth. Someone has obviously gone to some effort to get access to this beach putting handlines down some steep slippery bits of the route down the cliff. At the bottom is a sign on the lines of "costume not required" which the young lady I was with interpreted as meaning "otherwise do you have to come in fancy dress" ??!!

Anyway there is an open adit at the back of this beach but didn't have any gear with us so no idea how far it goes.
Also heard rumours that the adit of Swanpool Mine was open not so long ago, but that whole area is extensively developed with flats etc, some very new looking, & the mine plans are not precise enough to indicate exactly where it was. Anyone been there?

I actually had a quick look up it again last night; didn't get very far though. There are large crabs all over the tunnel, and they like dropping off the walls and ceiling when the light hits them. The biggest was 4.5"! I got in about 15m and one fell down the back of my boiler suit and started nipping me, and it was too much for me to handle at that point! Will have to come back with a team.

This is an amusing anecdote. :thumbsup:

I think there has been some confusion in this thread between the adit on Maenporth beach (which drains the area across the road behind the beach) and the sewer outfall on Pennance Point (Stack Point). Underwhere's reply is spot on apart from his grid refs perhaps. I was born and grew up locally and knew Swanpool and Maenporth well from childhood, now a long time ago! The area behind Maenporth beach drained by the adit in question is now quite open and exposed and heavily turned over by the resident ducks and geese. It used to be much more densely wooded and the stream through it followed a more distinct path to the iron grid at the adit entry. Toby Hale seems to have followed it right through from the beach back to the lagoon - a braver man than me! I don't mind adits or crabs, but adits and crabs together....

Hi there I can answer your questions, me and
My mate have just come out of it.
It leads behind the car park to resevoir can be done with waders when time is right out. Was fun and worth the time