Sirius Minerals Forum

can I have some of the stuff sailerchief is on humming birds Arizona spring eh

1300 mining jobs to go in Yorkshire coal next year now where can we find a couple of thousand mining jobs in Yorkshire answers on a post card please mmmm

Whose to say a TBM cant't be used in a mining operation? Having worked at Boulby, I can see a great potential for such a use in that environment. The rock stresses are so high there (They will be no different here), that permanent tunnels (Conveyors, ventilation and transport) are not installed in the potash, as the tunnels close in extemely quickly due to the rock stresses, instead they are driven in the halite (Salt) below, which is more competent and the mine workings directly above in the potash relieve the stress, even then rock bursts are still comon. A circular tunnel is intrinscially more stable than a square one and also ventilation pressure losses are much lower, So there could be benefits in using a TBM for main ventilation drives.

Again Boulby has large trunk conveyors, up to 10km in length (as did Selby), the proposal is not for one long conveyor but a series of smaller conveyors. Tunneling machines being the same as in brunels days is complete poppycock - yes conventional shield tunneling may be, TBM's are a very different piece of equipment, utilising a shield. The long term operating costs of the conveyor system will be far cheaper than a pumped sytem, wear and corrosion in pumping a alkaline, high solid content salt solution will be massive, with the pipes furring up over a period of time. Then you have the dewatering issues at the other end (Which uses a massive amount of energy) as well as the energy sed in actually pumping.

1. There is precedent for such a scheme (Although not quite as long) at the Selby super pit. 2. Although it sounds a long tunnel, on a mine of this type it is not particularly significant. Boulby has several hundred miles of tunnels in the salt layer under the potash carrying conveyors, these tunnels are in the order of 8m wide by 3.5m high, in what is ultimately uneconomic ground - it is mined this way in order keep the permanent accesses open, as the potash is too unstable for permanent mine infrastructure.

In some respects I agree with the issue of the economics of the tunnel and I am somewhat sceptical, however I wouldn't rule it completely out: -

This sounds like a better system, with maintenance in mind less down time. the slurry pipe would have been big trouble if there was a blockage.

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The inital proposal prior to planning has an excellent location for the potash mine showing huge regard for the environment. The key element is an export pipeline moving ther potash outside the Yorkshire National Park for processing. The formal planning application should be successful.

Now looks like the worm has turned with the euro-fiasco having a stay of execution. I expect CF will have the big boys queuing up for piece of the action. See you all at the AGM...