Not much of interest (economically) here. Pity they dont know the difference betweeen "stratiform" (which it categorically is not !!) and "stratabound" (which it is - in the Great Limestone).

If they cannot get the basics right dont see them having much chance !!!

Latest from Minco on 13th June at:

http://www.investegate.co.uk/minco-plc--mio-/rns/updates-on-drilling-results/201406130903055735J/ 

or from their website at:

http://www.mincoplc.com/fileadmin/user_upload/minco_news/2014/2014_06_13_MINCO__NPennines_Results_.pdf 

Lots to read. Places identified. Borehole results given etc. etc.

Dave Greenwood

But oh dear me - they claim it is "stratiform" when it is clearly "stratabound" - not just symantics but a fundamental geological error.

Stratiform would be if the mineralization was formed contemporaneously with the sediments when it clearly is epigenetic (later) and thus must be stratabound by definition.

Oh dear have they no geologist or is this deliberately misleading as "stratiform" would imply better target potenial?

Very technically umimpressive (as are the drill results !!)

As admirarably, put by Minegeo, these results are not dramatic, and perhaps more perplexing to me are the poor results from the Wellhope bore hole.
Anglo proved that Zinc was present in reasonable amounts here but were put off by their extraction costs.
Minco's results do not confirm this.

Minegeo. I completely agree. This is a real dog's breakfast of an RNS. Their confusion over stratiform and stratabound presumably comes from the fact that they are trying to impose an "Irish Type" scenario onto the Northern Pennines which is completely wrong. I also find this sentence from the RNS (p 6) unbelievable:

“Secondly, and more importantly, the demonstration for the first time of significant stratiform mineralisation within the Great Limestone counters the long held belief that the mineralisation is dominantly of ‘vein type’ and significantly improves the potential for major lenses of stratiform within the more massive and thicker, basal limestone succession.”

Although it is difficult to get a precise figure I think Dunham has a value of around 15-20% for the proportion of ore raised from flats for the NPO as a whole and this figure would be much higher for the GL. To say that this is the first time that "significant stratiform [their word] mineralisation" has been found in the GL is a schoolboy howler of the highest degree.

Also in relation to deep drilling, they note that CA-001 passed through a fault on the Rampgill structure but fail to mention that in a previous release their log shows that this was in the Melmerby Scar Limestone and that it was unmineralised i.e. they tested the fault at their target horizon and found nothing.

Dave Greenwood

To be a bit of the devil's advocate here, they weren't talking (at the public meeting at least) about the non-vein mineralisation as being like the flats but more secondary with decreasing concentration as you moved away from the vein.

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gNick. I can't really see how there could be two phases of mineralisation, one forming the flats and the other producing the Minco style deposits. I think it is far more likely that the workable flats simple pass into lower grade material as you move away from the vein and that those areas were left unworked. Note that minor lead flats were seen in the GL in the Beaumont (Allenheads) Mine Main Haulage Level between Old Vein and Henry's Vein in areas not worked by the Old Man. Also note that the flats are actually larger than those shown on various mine plans because the Old Man had often backfilled them with deads before the mines were systematically surveyed. This is shown on W B Lead Mine plans by a series of tiny blue dots around the sky blue wash used for the High Flat horizon - so all the diagrams of flats in various publications probably underestimate their true extent.

Dave Greenwood

That might be the case, though I got the impression that the ore was more disseminated in the rock. I'm no geologist so the direct meaning of what was said might well be different to what I thought it meant.
Given that they seem to be making basic errors in the report I do wonder what is going on as that isn't exactly going to help in selling the mine as a commercial proposition.

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It is quite true that there is a gradation from the sort of flats worked by the Old Man to the more disseminated material in the limestone surrounding them. This would have been very obvious in the case of galena with the silvery crystals contrasting with the limestone. For example there was a deposit like that with 2-4 mm cubes of galena in the GL on the 80 Fathom Level near Sikehead Shaft at Whiteheaps Mine next to the fluorspar in the White Vein. It will have been less true for sphalerite with its brownish colour that might have been difficult to distinguish from other yellowish brown minerals such as ankerite and siderite - especially in candle light and with no immediate chemical analysis. That may be why there seems to be a considerable amount of Zn rich material beyond the limits of the old workings at Nenthead.

Another factor is that according to the old accounts (such as Sopwith and Wallace) the flats worked by the Old Man were often very vughy and were lined with crystals (as can/could be seen in Smallcleugh and elsewhere). This meant that the ore was obvious and the presence of vughs would have made the ground easy to work. In contrast some of the material illustrated in the Minco presentations would have been much more difficult to work - more like driving a drift in solid limestone. Hard to do by hand!

It is important to remember that the miners were paid on piecework so there must have been a strong temptation to high-grade all the time and it would have been up to the management, such as it was, to try to maximise recovery. When I had access to the Allenheads Bargain Books in the 1970s I remember reading that Partnerships reworking old ground in the flats were usually paid a relatively high price per bing, suggesting the ore was not very rich in that sort of situation.

Dave Greenwood

Dave, in one account I have read, by Wallace, who was a manager at Nenthead, the miners were paid more for galena from the flats because it was very clean and needed minimum dressing.
(as you might expect from crystallised galena).
Other reasons cited, as you mentioned, were the flats were difficult to work, and also inferred, it would encourage miners to find new flats.
He went on state that the majority, of flats had been discovered by miners, searching after ore, and not by the L.L.C. Itself

Minegeo

Are you sure about what you said?
Let me remind you...
You said...
"But oh dear me - they claim it is "stratiform" when it is clearly "stratabound" - not just symantics but a fundamental geological error."

Did'nt you mean to say "semantics" rather than "symantics"..?

Oh! Dear me....

For the benefit of others who may one day not know the difference between "stratiform" or "stratbound" or innocently
mistake "symantics" for "semantics"....this is what he expertly probably wished he had said...........
SEMANTICS....the branch of linguistics and logic concerned with meaning. The two main areas are logical semantics, concerned with matters such as sense and reference and presupposition and implication, and lexical semantics, concerned with the analysis of word meanings and relations between them

John. That would make sense. The small flats seen in the Beaumont Mine Main Haulage Level were just lumps of solid galena so it could just have been hand picked. I have a photo somewhere that I will try to find and post. Other accounts in the Bargain Books showed that in some places the flats were silicified and very hard to work. Also probably lethal from the silicosis. There was a West Cumbrian iron ore mine at Lamplugh that was very similar and all the miners ended up in the local graveyard.

Finding ore was very much in the interests of the miners and until Sopwith came along I don't think there was much in the way of organised exploration - a case of "there it is, where it is" as they said in Cornwall. Sopwith did introduce a more systematic approach an there were several "exploration plans" amongst the Allendale Estate records that recorded the progress of individual cross cuts at various places in Weardale and Allendale. Incidentally, miners finding ore did not stop with the Old Man. A team of miners at Groverake followed the vein upwards from about the 30 Fathom Level and discovered the three way split in the Firestone Sill that led to the development of the Firestone Incline. Who needs Geologists? LOL.

Dave Greenwood.

Some circumstantial information - Minco were planning to take a lease of buildings at Nenthead. they have now changed their mind and are not taking the lease........

The discussion about flats is interesting. The Smallcleugh flats can be explored to the perimeter of the workings in the majority of the mine. The flats are very much as depicted by Wallace in 1856.

Flats in the Great limestone in the Hardshins vein area of Rampgill-Barneycraig Mine are like a network of low tubes, which might be following the joint pattern. Not much mineralisation visible to the naked eye and not much galena or blende to be seen on the walls.

Miners who worked in Nentsberry Mine in the period up to 1932 reported that they were keen to follow the side leads. The inherited knowledge was that these might lead to flats, but none did so. Nentsberry orebody pattern is rather like a scaled up version of the Hardshins vein flats.

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The presence of flats stemming from thin leads off the vein seems to be a common thread in the Pennines. The Boltsburn flats in the GL are said to have been like that with a zone of iron mineralisation between them and the vein. Similar structures were present at Rotherhope Fell in the TBL and the W B Lead plans of Allenheads also showed leads running off Old Vein. It is almost as if the flats formed in a sort of backwater where the mineralising solutions were more or less stagnant and quietly ate into the limestone - almost like cave formation. We did a few fluid inclusion temperature measurements on fluorite from flats in the 1970s and they all came out quite low - from memory around 120 to 140 C. I was once in the flats at the east end of Allenheads where Wentworth Vein meets Henry's Vein but it was very hard to see what was going on because they had been submerged for over 60 years and all the iron minerals had oxidised to a muddy brown coloured sludge that covered everything.

One thing the Old Man had over us was the very slow pace of the work and the fact that he was cheek by jowl with mineralisation so he must have seen a lot of detail that we miss with our drill - blast - muck-out - timber-up cycle of mining. Some of the dates recorded on Allenheads plans just showed how slow things could be when driving cross-cuts in the GL where progress was measured in as little as a few feet per week.

Dave Greenwood.

Talking about the flats and how hard they were, Wallace also records that parts of Scaleburn were so hard that they left them.
He also states, our miners have a phrase "as hard as a Scaleburn twitch"
I must add in our explorations in Scaleburn did not see any obvious remaining ore, but of course it was worked after Wallace's time by both Tynedale Zinc and VM.

John. I think the hardness would depend on two factors. First whether or not the flat was vughy and secondly on the silica content. The latter seems to be very widely variable with Dunham (p 83) quoting figures ranging from 2.9% to 66.24% for material representative of the metasomatised limestone. This would fit in with the overall picture of the mineralisation where the vein walls are sometimes silicified and sometimes not. Dunham also notes (p 126) that the main gangue mineral in the Rotherhope Fell Flats in the TBL was silica mainly as chalcedony, which must have made them very hard to work. I once read a paper dated about 1900-10 on the petrology of these flats but at the moment I can't bring it to mind and it does not seem to be listed in Dunham's references.

I guess Scaleburn must have been picked pretty clean given that it was reworked twice although some of the Minco boreholes do seem to have found mineralised ground above and below old stopes - for example in CA-006 and CA-008 as shown on p 49 of their 2013 AGM presentation (the one used by Roger Bade in his Friends of Killhope article).

Dave Greenwood

Whynagg - :oops: Sorry about the typing error - did not spot it. However a simple typing error does not change the point about the Minco release being sloppy and technically inaccurate however.

Dave, I think that their 'hit' at Scaleburn is an extension of Scaleburn North Vein which was very rich around 1810, and was cited by Wallace as a possible target. However as far as I am aware no mining was carried out.
Peter, I cannot agree with you over Wallace's famous Smallcleugh flat plan. What I think it shows is the flats extent at the low flat horizon of the GL.and by inference the flats they had discovered by 1850.
The later flat discoveries, presumably,are at the high flat horizon, eg.the incline, waterblast and others at this horizon.
The access shaft to the incline flats, at the end of the hard cross cut, has a date on it around 1865 on one of my plans, and so I am suggesting all these high flats date after Walllaces plan.
Presumably the blank rise in wheel flat is an attempt to look for a high flat, obviouslly unsuccessfully.

Latest presentation from Minco. Dated 12th April 2014 but apparently only just posted on their website. Covers all their projects and includes more maps and photos of the Nenthead work at:

http://www.mincoplc.com/fileadmin/user_upload/presentations/2014%2003%2012%20Minco%20Presentation.pdf 

Quote from p 45 of the above presentation:

"Mississippi-type lead & zinc mineralisation
should really be called Northern Pennine type
as emigrating Northern Pennine miners first
recognised geological similarities in the
eighteenth century."

It seems the penny has finally dropped that this is not Irish Type!

Also something has been/ will be published in the Hexham Courant but so far I have no details.

Dave Greenwood

Nothing new in the Courant article.

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