The Mine Shafts Project. Hydrology.

[The Old Ruminator]

If only to find somewhere cool. The Hole In The Wall yesterday.

 

[The Old Ruminator]

Yes cool yesterday but today both hot and knackered.

 

[The Old Ruminator]

Still ongoing progress. 16.5m from the entrance heading to those mythical caverns ( maybe ).

 

[The Old Ruminator]

Big effort by The Terrible Twins yesterday.
60 bags hauled out and emptied ready for some more rapid speleogenises. Looking a tiny bit more encouraging.

 

[The Old Ruminator]

Had to stop on the way home.

 

[The Old Ruminator]

At the end. 1 is the pink lode. 2 is what the miners called White Spar . Both related to byrite.3 the ongoing mud filled vugh which we have now followed for 16.5 m A natural roof line there.

 

[The Old Ruminator]

Liniar vugh 200 mm wide in the dig roof.

 

[mrodoc]

Keep the faith!

 

[The Old Ruminator]

Vugh line and possible margin with the Devonian slate beds right. More commonly seen in the other section of the mine. The miners called the unproductive slate beds " Killas " but it meant easy working.

 

[The Old Ruminator]

Mr O'Doc. We shall carry on until one of us dies. ( for me it will be the second time ).

 

[The Old Ruminator]

Long view of the dig face. Pink lode left. Tools where the softer lode has been cut.

 

[The Old Ruminator]

Closer view of the possible limestone/ slate interface.



The Slates.

Bedrock Geology: Cutcombe Slates Member - Slate​

Devonian period (Givetian age).
Sedimentary Bedrock, from an environment of open seas with pelagite deposits.
These sedimentary rocks are marine in origin (pelagic). They are detrital, comprising very-fine grained accumulated deposits of silica, carbonate or biogenic material, forming thinly laminated or structureless beds.

If we are adjacent to the slates it will be important for us. For the miners the slates were workable by pick. We would have the softer lode one side and the slates the other making hand excavation a better prospect. The Devonian Limestone is quite the opposite.

Devonian period (Givetian age).
Sedimentary Bedrock, from an environment of shallow carbonate seas.
These sedimentary rocks are shallow-marine in origin. They are biogenic and detrital, generally comprising carbonate material (coral, shell fragments), forming beds and locally reefs.

We can manage that though

 

[The Old Ruminator]

The NE coffin level where the friable Killas has collapsed into the workings. Limestone wall left.

 

[The Old Ruminator]

Geology at The Bridge.

1 Cutcombe Slates ( Killas )
2 Devonian Limestone
3 Byrite Lode.

 

[The Old Ruminator]

" White Spar " in the NE level. Possibly Chalcocite the grey stripes. The source of the copper.

 

[Brains]

Byrite... What is this referring to, I am unfamiliar with the word? Google tells me it should be baryte or pyrite, then offers crushed byrite (undefined) as a mineral filler? Is it a regional term?
Thanks

 

[The Old Ruminator]

Small overhead stope showing the lode in limestone with Killas left.

 

[The Old Ruminator]

Byrite... What is this referring to, I am unfamiliar with the word? Google tells me it should be baryte or pyrite, then offers crushed byrite (undefined) as a mineral filler? Is it a regional term?
Thanks

Oopps sorry. Sounds like an advertising site.

Barite is a heavy, white or colorless barium sulfate mineral (BaSO₄) with a high specific gravity, named for the Greek word for "heavy". It is the main source of the element barium and is widely used as a weighting agent in oil and gas drilling fluids, a filler in paints, plastics, and paper, and for medical imaging of the intestinal tract. Also Baryte. The miners called it " Heavy Spar " or "White Spar".

 

[The Old Ruminator]

Down yer in Zummerset we spell a lot o things diff'rent. So do did the Cornish miners who worked in the mine. One such is " Scrowle ". A place where the lode is intersected by a fault.

 

[Brains]

Oopps sorry. Sounds like an advertising site.

Barite is a heavy, white or colorless barium sulfate mineral (BaSO₄) with a high specific gravity, named for the Greek word for "heavy". It is the main source of the element barium and is widely used as a weighting agent in oil and gas drilling fluids, a filler in paints, plastics, and paper, and for medical imaging of the intestinal tract. Also Baryte. The miners called it " Heavy Spar " or "White Spar".

I expected baryte, but didn't want to assume. Thanks.
In addition I have heard baryte/ barite called caulk in Derbyshire, and white spar has been used to refer to milky calcite. Locally in the peak baryte can form as large botryoidal overgrowths on darker minerals. When broken these give very distinctive (bulls)eye appearance.