Northerner
5 years ago
So basically, the company that owns South Crofty, Strongbow Exploration (TSX-V:SBW) - has come across a potentially interesting copper-tin prospect.

In the once great Gwennap mining district, between the old Consolidated and United mines, and in very close proximity to the end of the Wheal Maid decline (1980s).

Drilling by Cornish Lithium... in search of lithium brines at 1000m depths, has intersected 15 metres of 7.5% copper & 1.2% tin, at only 100 metres depth. This is an exceptionally high grade by any measure.

Just 1 intersection, so there is no confirmation of the orientation/true width at the moment. Most of the major lodes in this area seem to dip 20-30 degrees North though (Dines, p418-28). If this was dipping at 20 degrees North, it would be about 6 metres wide by my calculation. Alternatively, if it was south dipping parallel to the hole, it might only be a metre or so.

So... what is it? Is it an analogue to the mineralisation at Wheal Jane/Mt Wellington - but wasnt that only associated with the footwall of elvans? Could the "old men" really have missed a massive orebody right in the middle of the "richest square mile"?

The following plan has been published by Strongbow:

https://www.strongbowexploration.com/site/assets/files/5332/2020-04-07_united_downs_mineral_rights_held_by_strongbow.jpg 

The intersection is in a zone which appears to be between Consolidated and United, and they've drawn on a projected strike, slightly fortitously, but roughly parallel with the lodes in the area. In the east, that takes it just north of the first borehole, but just south of a crosscut from Consolidated. And then in the west, again 50m or so beyond the end of the Wheal Maid decline, and similarly just north of a driveage from United mines... this seems pretty expedient, but again, its not impossible...

So is it just a blip? A pocket of localised mineralisation? Or a major new lode/system? Would be interesting to see a plan of United Mines with crosscourses on as mineralisation tends to be enriched near crosscourses.

Anyway, if it isn't a blip, and this is a major new lode in the middle of this old mining district - at these kinds of grades... we're looking at something potentially very significant.

Original press release by Strongbow:
https://www.strongbowexploration.com/site/assets/files/5332/2020-07-02_united_downs.pdf 

FTR; I am a mining engineer, but not affiliated with Strongbow in any way!

Northerner
5 years ago
I don't want to get drawn into what Mihalop & Wrathall are like, and rating the whole prospect on that. Some pretty dodgy people have found some pretty big mines in the past. And I've never met either of them anyway. All I will say is, there has to be a balance - you have to have some flair, as well as some substance and knowledge. It's no use being boring, honest or pessimistic, in the game they're in - or you won't get any funding - so you won't be able to drill anything, and then you most certainly won't find anything!

Some of the greatest mineral deposit discoveries in the world, of the past 25 years (Oyu Tolgoi, Voiseys Bay, Kamoa-Kakula) have been discovered by teams led by a financier called Bob Friedland, who is a complete nutter and almost certainly more of a salesman than a geologist. Of course it was wildly speculative, but if he didn't pull the $$$ in, they wouldn't have found anything, and thats all there is to it.

I have to say though - I don't understand what CLi are doing at all, I don't doubt for a second that water containing lithium exists in geothermal brines in various area of Cornwall, but I don't understand what processes they could use to economically recover such low concentrations of lithium. Again, I dont doubt its technically possible, but I've got no reason to suppose its economically viable either now or foreseeably. If there is much substance behind the proposition, they aren't very forthcoming about it. So I agree with you on CLi, and we'll leave that there.

But that's by the by. One way or another, they've accidentally intersected a significant amount of copper, at a relatively shallow depth - and that doesn't belong to them, it belongs to Strongbow Exploration, ie. the owners of the long ailing South Crofty. And what I do know is enough 7% copper is economically viable.

So... on the substantive matter... has it been cut before... the first significant thing is... they've intersected 15m of mineralised drill core. Not 15 metres of void. It'd be nice to see some pictures and core logs to prove that, unusual not to post that in the Press Release, to be honest. But thats the first indication that maybe the old men didn't know about this mineralisation, because they wouldn't have left 7.5% copper behind. That would have been a reasonable grade, even for Consols/United.

I get what you're saying, there are a lot of very old pre-survey workings from the early 18th century, maybe even before - in the area. But to cut a decent grade of copper you might need to be a bit below surface, it could be possible to miss from just trenching. It might have a surface expression as < 1% tin (and if its fine tin like Wheal Jane, then recovered black tin could be very low) so wouldn't have necessarily been of much interest.

As for the crosscut drives south from Consols at 40F, and the deeper drives north from United - are they not all already on the plan in grey?

https://www.strongbowexploration.com/site/assets/files/5332/2020-04-07_united_downs_mineral_rights_held_by_strongbow.jpg 

Are they not also in this 3D model? (see 2:30)
https://www.facebook.com/407369656071364/videos/1052482168226773/ 

There simply doesn't seem to be any deeper driveages from Consols through all the way to United on any of the plans I've seen. And you can project on this structure at a northerly dip, and it somehow misses everything, including the Wheal Maid decline. It's threading an eye through a needle, it seems highly improbable. But prove its impossible? Did they not do any diamond drilling south from the Wheal Maid decline?

https://i.imgur.com/pFbKiuP.png  Yes, it would mean Wheal Maid decline stopped short by maybe 50m, and both Consols and United missed it by even less. But who knows, maybe they did...

Quote:

Besides, if they start doing anything up there, they are going to need an awful lot of large steam engines.



I think you'll find a few electric pumps will do the job with no problem. The main issue would be water treatment. Is Wheal Maid decline hydrologically linked to Consols or United? What level does the County Adit drain United to?

Finally I would concur with what you've said about Redmoor. Seems like a very professional team there, and they've found what seems to be quite a lot of decent width very high grade tungsten mineralisation, especially where the sheeted vein nears the granite-killas contact there. A lot of potential there, some reasonable tin to the west as well but its mainly tungsten. But the parent company has run out of money, so perhaps they do need to be a bit more bullish about the prospects there... no drilling = no progress = no mining.

As for Wheal Concord (80s), they spent a bit of money digging holes, but they didn't find very much of any significance. I doubt they ever sampled any 7% copper and 1.2% tin over 14 metres anyway. Swashbuckling maybe, but I don't think its a very good model for what commercially successful mineral exploration looks like.
AR
  • AR
  • 50.2% (Neutral)
  • Newbie
5 years ago
Not my patch so I'm not familiar with the nature of the mineralisation, but I am familiar with the drilling that gave rise to Riber Mine being opened in the early 1950s. The drill core showed it had gone through rich, uncut vein, the incline was driven, only to find that the coring had gone through a stalch left in an old man's stope...
Follow the horses, Johnny my laddie, follow the horses canny lad-oh!
Roy Morton
5 years ago
It’s not beyond the realms of possibility that the drilled through a pillar and that either side has already been had by the old men.
After all it’s only one hole
"You Chinese think of everything!"
"But I''m not Chinese!"
"Then you must have forgotten something!"
John Lawson
5 years ago
Hi I look at this as a purely accidental discovery! One wonders how the lithium company came to carry out the drilling on Strongbow’s lease. But a couple more drill holes will tell the mining companies if they have a good deposit or not!
Hopefully it will be the former, but I remember the Riber Mine in Derbyshire, where a good core lead to them sinking a Mine, only to discover once they were down there, the drill core had cut through a side of the vein which had been removed by the old man!
Hence it was a waste of time and effort!
Roy Morton
5 years ago
I should think Strongbow would welcome any source of cash at the moment, whether it's from lithium drillers or whatever.
Their lease area in Gwennap is large, and having taken up the properties that were once in the hands of Tehidy Minerals, there are lots of other places that they also have claim to.

"You Chinese think of everything!"
"But I''m not Chinese!"
"Then you must have forgotten something!"
derrick man
5 years ago
I don’t have the detail to hand, and I’ve forgotten most of what I knew forty-odd years ago about United Downs, but I find it extremely difficult to believe that the “old man” would leave a deposit of any value behind, in an area as intensively worked as United.

Or that they would simply miss it completely.

Strikes me as something similar to the Wide Lode - high values in one place, pinching out to nothing a few metres away amid a lot of faults, water and rotten ground.

No, the old man knew his business, as did the Captains of the day. If there was ever anything there, they had it long ago.

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