Well i'm certainly looking forward to a tour down this 37.5km tunnel that ends near my house.

No-one else got any worries/doubts about a tunnel that size ?

The solution pipeline has been scrapped in favour of underground conveyors adding $280M USD to the capex but lowering operating costs by $10/t

http://yorkpotash.co.uk/news/new-mineral-transport-system-announced/ 

IMHO this project is looking even less likely to ever see the light of day! 😞

---

No-one else got any worries/doubts about a tunnel that size ?

Depends on the bore of the tunnel I guess. The London water ring main is 80k long, with a bore of around 2.5m, from memory.

The Scar House Dam aqueduct gravity feeds water to Bradford over 51k, largely underground.

We only tend to hear about the large scale tunneling projects like Crossrail, which are massively expensive. Small bore tunneling is much more common. Though whether the York Potash proposal is feasible, who knows. I'd guess the biggest unknown would be the geology.

I wonder if an underground conveyor has been considered to the Whitby branch line for rail.

Lovely line from Whitby to Middlesbrough, one of the best in the country in fact, but the passenger service is timed in geological eras. The chance of getting the multi-wagoned freight trains used by the likes of Boulby down it on a regular basis is substantially less than zero I'd imagine.

That company statement sounds a bit desperate to my ears.

Depends on the bore of the tunnel I guess. The London water ring main is 80k long, with a bore of around 2.5m, from memory.

6m according to their website (not sure what the 70s entertainment centre is for)



Bigger than the channel tunnel service tunnel which is 4.8m. This would be the 5th longest tunnel in the world if Wikipedia is correct.

6m just sounds mental, you would be able to drive a double decker bus down it.

But this is the figure shown on the mock-up
http://yorkpotash.co.uk/site/assets/files/1013/project_overview_february2014.jpg 

Do they mean 6 square meters ???
Which would be a more sensible diameter of about 2.75m ?

6m according to their website (not sure what the 70s entertainment centre is for)



Bigger than the channel tunnel service tunnel which is 4.8m. This would be the 5th longest tunnel in the world if Wikipedia is correct.

Exactly, can't see this ever being built, where are they planning to put the 10 million plus cubic metres of spoil it will create? Oh and the 70's entertainment system appears to be a loco for access/maintenance!! :ohmygod:

---

6m diameter? I don't think so! Why would it need to be that size?

Boulby's 2000T/h trunk conveyors (Theoretical capacity of 17 million tonnes per year!) are 4' wide, if you installed a manrider as the picture suggests, thats 6', so assuming you had 2'clear of the sidewall each side and a 4' speration (This is being generous!) then thats 14' or just over 4m, why increase the diameter by another 2m?

As for getting consents for that, it could be interesting!

How wide is a manrider?

With a 4ft belt you`ve also got the outside structure and roller width,

And being full round construction and the position as in photo,there would not be much spare out of 6m

Sorry should have been clear, its 4' structure, not belt. With regards to the manrider, the tunnel is purely for a conveyor belt to take ROM product for refining, so you only have a belt maintenance team required, how big a manrider does it need? 4' wide would be more than big enough! (Unless they're intending on employing some real porkers of course!) As someone as already pointed out, 6m is bigger diameter than the service tunnel on the channel tunnel!

That said when you're looking for $7 Billion!, whats another 800 million between friends?

The main tunnel at Gascoigne Wood (Selby) was driven by a 5.8m diameter Robbins machine. By the time you had installed a conveyor capable of doing 15m tonnes per year plus the loco track there wasn't much room for anything else. Any ground movement fairly quickly caused the conveyor to be pushed off line and resulted in some major back ripping in faulted areas. 6m sounds about right to me.

I'll put a picture of the tunnel on the Gascoingne Wood site - I can't figure out how to get it to appear directly in the forum!

Its an interesting proposal, and I'm glad you bought up Selby, I was looking for the size of the conveyor drift earlier. The big problem obviously with a round tunnel is although they are easy to create, as this can be done by mechanised methods (One like this would be TBM), they are inneficient is space use - you have to infill the invert to create a level surface and give you reasonable useable width.

I would love to go back to Boulby sometime, I spent a few weeks of my time up there in 1999 building new conveyor into the South of the mine, as the water was receeding - some shifts we would start in the dry and by the end of it we wold have caught up with the water and would find ourselves in it! I digress a little there, what got me thinking of that was the comment regarding downtime due to ground movement - as we were installing the conveyor we were suspending it by chains from the roof of the tunnel, the idea being to solve the issue of spilt material jamming the conveyor. That would make it more susceptible to ground movement - the roof is more likely to move than the floor, obviously Boulby is very susceptible to movemnt, so I wonder of they have hd an problems with that - mind it would be easily solved as you could jack the conveyor on the threads on the connector to the chain.

Another one I would love to see is the actual belt design - 38kM is a heck of a way and the starting current on that is going to be massive, particularly when starting with a loaded belt, never mind the tensile strength, I would have thought the bst way of dealing with this would be to use a series of belts, feeding onto each other.

Should have read the actual press release there, it answers a few of my questions, it would be a great project from an engineering viewpoint - it puts most mining projects in a very different light financially - $280 Million dollars just for that element.

3 proper shafts to be sunk (Up to 350m Deep) as well as two smaller launch shafts at each end (Probably about 20m deep). Building a TBM at 350m alone is probably going to be a record!

If this job goes ahead (Interesting one for me, is the operations manager Graham Clarke, was Deputy Mine Manager at Boulby when I was up there, so he defianately has a working experience.) it'll be strange, nobody has sunk a shaft in the UK for god knows how long and all of the sudden one project comes along wanting to sink several!

Presumably full round ring`s have been looked at because they will be nearing old Iron Stone workings towards end of route,were there not Gas problems with these workings?

AFAIK the problem with the old ironstone workings is oxygen depletion through chemical reaction rather than ingress of gases, but I recall from my visit to Boulby that you get firedamp in the salt beds, hence why the mine's on the same rules as a coal mine regarding electrical equipment.

---

Presumably full round ring`s have been looked at because they will be nearing old Iron Stone workings towards end of route,were there not Gas problems with these workings?

There are a couple of isolated incidents of gas in Cleveland ironstone such as the explosion at Lingdale in 1953.

http://www.communigate.co.uk/ne/lingdaleitshistory/page100.phtml 

But as a general rule, no.

In the Whitby Gazette

http://www.whitbygazette.co.uk/news/business/potash-tunnel-will-reduce-impact-of-mine-1-6478687 

http://goo.gl/QUwzSC 





Potash tunnel will ‘reduce impact of mine’

05/03/14

The £167m tunnel which will transport polyhalite from a mine near Sneatonthorpe will be comparable in size to the Channel Tunnel.

Plans to construct a pipeline from the Doves Nest Farm site to a processing plant at Teesside have been abandoned in favour of a six-metre tunnel which will run the 37km distance at a depth of 350m.

York Potash spokesperson Gareth Edmunds said: “It addresses the concerns about the pipeline put forward during public consultation. We have always said we would try and reduce the impact where we sensibly can, so we feel good about being able to change and we feel it’s a positive impact on the project.”

Sirius says the tunnel will reduce surface buildings and environmental impact by 70 per cent and allow the mine a greater capacity.

“It’s going to cost more in the long run,” said Mr Edmunds. “But we think it’s worth it.”

Mr Edmunds said the idea of a tunnel was discussed when initial plans for the mine were made but it was thought that a pipeline would have a lower cost and impact.

Following consultation it was decided that the extra infrastructure required to make a pipeline work meant it was no longer the viable option. It would have required a trench 45m wide to be dug along the length of the route and issues arose when attempting to cross rivers or skirt around sites of specific scientific interest. “The impact goes up and the cost goes up with it,” said Mr Edmunds.

The 6m wide tunnel will have a conveyor belt and a roadway running alongside it which will allow access to maintenance vehicles.

It will have three access points running along the length of it, and Mr Edmunds said this makes it effectively five mining tunnels, of a length regularly seen in underground mining operations.

However in total, the mine will measure up to the Channel tunnel, which is split into three 7.8m sections which run for 38km underneath the English Channel.

The tunnel would see over 1 million cubic metres of bedrock brought to the surface - the waste material could almost fill the inside of Wembley Stadium.

But the mining company says there would be a degree of compression which would reduce the impact, and suggested that if spread across an area of around 20 hectares at each access point, the ground level would only be raised by about a metre.

---

"...the mining company says there would be a degree of compression which would reduce the impact"

That's a remarkable assertion. It seems to be claiming that the spoil could be compressed to less than the volume it occupied prior to extraction!

The claim that the spoil would occupy 60ha (one 20ha tip at each access point) at 1m thick is difficult to reconcile with the volume of tunnel spoil. 37km times 6m diam equates to 1.05m m3. Add a minimum of 5% for overbreak, access points, etc, and call it 1.1m m3. 60ha is 60,000 m2. This comes out at 18.3m thickness of tip before allowing for the expansion of volume of rock once broken. Maybe the magical compression technology will compress the spoil by a factor of 18!

The statement that a pipeline would have required a 45m wide trench must surely be a typo for 4.5M?