On my recent trip to North Wales, I turned my attention to the cluster of slate mines in the Corwen and Glyn Ceiriog area, eg Moel-Fferna, Cambrian and Penarth.

It so happened that I had recently read a report about the 1934 Gresford coal mine disaster which mentioned that Gresford had two vertical shafts called the Dennis and Martin shafts.
On later reading about Cambrian slate mine, I discovered these names again: - Dennis quarry or quarry pool which used to be filled with water, and also a Martins quarry.
I was wondering if there is any kind of connection here?

Also there is a very nice cog roof support in Moel-Fferna made of timber and said to be more typical of coal mines. (I have regrettably not yet seen this structure myself, as I don't do SRT which is necessary to enter Moel) Apparently this slate mine employed coal miners at one time.

In the case of Moel-Fferna, is it therefore possible that miners from Gresford found work in this slate quarry when the coal mine was closed for some months following the disaster? Just a very wild guess, as I know next to nothing about these eastern slate mines.

Does anyone know of other features, names etc which hint at a connection between slate quarrying and coal mining in this area?

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The use of cogs isn't restricted to coal mines, they can be found in various types of mine where a flattish seam was worked.

Although there may have been coal miners at Moel Fferna it may well be that a cog was used simply because it best suited the geology. The supporting stone work certainly seems more indicative of a quarryman's hand to my (in-expert)eyes.

Interesting point, RJV, It looks very much from at least what I saw at Penarth, that the slate strata here is bedded roughly horizontally, unlike in for example Cwmorthin where it has been tipped at an angle. Obviously this orientation of the slate veins would influence the quarrying techniques used. As you suggest the "cog" method used in Moel Fferna, could simply be a means to an end rather than necessarily indicating the presence of coal miners.

The slate here also appears more shale like in comparison to the Ffestiniog variety, as if the compression has not been as great.

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It so happened that I had recently read a report about the 1934 Gresford coal mine disaster which mentioned that Gresford had two vertical shafts called the Dennis and Martin shafts.
On later reading about Cambrian slate mine, I discovered these names again: - Dennis quarry or quarry pool which used to be filled with water, and also a Martins quarry.
I was wondering if there is any kind of connection here?

The coincidence of names suggests that investors named Dennis and named Martin were prominent in both enterprises. The Dennis family owned one of the region's largest brick and tile works, located at Ruabon; they may have invested in both Gresford Colliery and in Clwyd slate quarries. This is only a guess - but the coindence of names is rather suggestive.

I think Dennis was also involved with the Glyn Valley Tramway, and possibly the Snailbeach District Railway too.

Dennis family held about 45 to 50% of the mine but I dont know about the slate mine It was common though to name things after promenent people in the trade or area

. (I have regrettably not yet seen this structure myself, as I don't do SRT which is necessary to enter Moel)

Not true. An electron ladder will suffice.

Chris.

. (I have regrettably not yet seen this structure myself, as I don't do SRT which is necessary to enter Moel)

Not true. An electron ladder will suffice.

Chris.

Indeed it will. I was belayed in on my first ever trip... Having never done a Mine before that, I was cacking myself! All good fun though, and probably still my favourite mine.

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Dennis Quarry was named after Henry Dennis of Ruabon who was an engineer involved with Cambrian and other mines (including Snailbeach as mentioned already).

Wikipedia says that Henry Dennis and his son started a colliery at Gresford in 1907. I'm slightly confused here, as "our" Henry Dennis died in 1906! Seems clear that the Dennis family at Cambrian and Gresford are the same though.

Martin's was named after Sir Theodore Martin (1816-1909) who was also involved with Gresford. Prior to it being named "Martin's" after 1870, it was simply "Chwarel Uchaf" and had been working since around 1790.

So in short, yes, Dennis shaft/quarry & Martin's quarry are connected. Given the prominence of Henry Dennis and Sir Martin, there could well be other features dotted around the area bearing their names.

Company Details
Registered Office: Gresford Colliery, Wrexham, Denbighshire
Seams Worked: Main, Crank, Brassey
Power Used: Electric. Voltage: 3,300, 600 and 550
Class of Coal: Gas, Household, Steam
Source: 1933 Colliery Year Book and Coal Trades Directory. Published by The Louis Cassier Co. Ltd., from a copy held in the Scottish Mining Museum, Newtongrange, Midlothian

Company Directors
Chairman: Dennis, H. D., New Hall, Ruabon, Wrexham
Directors: Dennis, P. G. D., Stansty Park, Wrexham
Fraser, C. J. R., Capt., Lochavich, Argyllshire
Harrop, J. A., Gwersyllt Hill, Wrexham
Prescott, E., Cheshunt, Chilworth, Surrey
Wickham, R. T., 7, Black Friars, Chester
Secretary: Harrop, J. A.
Source: 1933 Colliery Year Book and Coal Trades Directory. Published by The Louis Cassier Co. Ltd., from a copy held in the Scottish Mining Museum, Newtongrange, Midlothian

The H D Dennis referenced by Peter is Henry Dyke Dennis, the son of the Henry Dennis for whom Dennis quarry was named.

Martin's was named after Sir Theodore Martin (1816-1909) who was also involved with Gresford. Prior to it being named "Martin's" after 1870, it was simply "Chwarel Uchaf" and had been working since around 1790.

So in short, yes, Dennis shaft/quarry & Martin's quarry are connected. Given the prominence of Henry Dennis and Sir Martin, there could well be other features dotted around the area bearing their names.

One of the "tramway" locomotive on the Glyn Valley Tramway, Sir Theodore, was named after Sir Theodore Martin.

Many thanks folks for the interesting info, re names.

As for electron ladders, yes, I could in theory get in this way, but would not consider it without a life line as well. As for getting back out again... 😮

(Just thinking of the only occassion I've ever used one...To gain access to a hearth-stone mine in Surrey)

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