Author Topic: Deep Mine Shaft Required  (Read 3124 times)

Online Fulk

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Re: Deep Mine Shaft Required
« Reply #25 on: August 29, 2019, 05:27:55 pm »


Boy Engineer:
Quote
but there do seem to be a lot of morons unable to put up shelves/do their own garden/avoid cheating on a partner/cook the most basic dish
;

Not to menmtion not knowing that if you shag someone they might get pregnant!

Offline cavemanmike

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Re: Deep Mine Shaft Required
« Reply #26 on: August 29, 2019, 08:29:09 pm »
Moron shags moron =super moron  ;D ;D

Online SamT

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Re: Deep Mine Shaft Required
« Reply #27 on: August 29, 2019, 10:21:44 pm »
Its all well amd good looking for existing shafts.. nenthead springs to mind.

 Wonder what the cost would be to sink a new purposes made shaft.  There must be parts of the land that would be suitable. Just a thought.

Offline Graigwen

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Re: Deep Mine Shaft Required
« Reply #28 on: August 29, 2019, 10:25:26 pm »
..... it kicked in at 7pm or when ever it was that coronation street finished and everyone stuck the kettle on. ....

It'll be when Love Island goes off now  ;D

In the old days. it used to be half time in the Cup Final.

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Online SamT

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Re: Deep Mine Shaft Required
« Reply #29 on: August 29, 2019, 10:26:29 pm »
..... it kicked in at 7pm or when ever it was that coronation street finished and everyone stuck the kettle on. ....

It'll be when Love Island goes off now  ;D

In the old days. it used to be half time in the Cup Final.

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Once a year!

Online Fulk

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Re: Deep Mine Shaft Required
« Reply #30 on: August 30, 2019, 10:08:29 am »
Back to the topic:

By my reckoning (anyone – feel free to check/query it), if you drop a mass of 2000 tonnes down a hole 250 m deep you generate 5 billion joules; if you lowered it down gently over the course of one day, it would generate 57,870 joules/sec, AKA watts. Apparently, the average house in the UK uses on average 429 watts (averaged over the course of one day), so the hole/weight contraption could power ~135 houses (if it was pulled up and let down once a day).

Is that a reasonable, viable output for the effort involved?

Online SamT

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Re: Deep Mine Shaft Required
« Reply #31 on: August 30, 2019, 12:18:26 pm »
Careful with your units and figures there Fulk.

a household cannot 'use' 429 watts, in the same way a car does not consume 40 miles/per gallon.   They are rates of use, and the total consumption depends on how long that rate is maintained.

I get your gist though.

The point is not to improve generating capacity.  The biggest problem we have on the grid at the moment is one of energy storage.  The old days of a few nuclear and coal fired power stations (not easy to turn up and down) meeting the base demand, with a few gas powered stations, (easier to modulate) to deal with fluctuations and about 4 pumped storage hydro installations to hit those short lived peaks are now behind us.

We need to find ways of storing the energy when we have excess, and releasing it when we need it, either in times of peak demand, or at times of low wind/solar resource.  This is just one option being explored, its relatively low tech, low impact, low maintenance and whilst its never going to be a Dinorwig, if enough smaller locations can be found, it might well provide part of the solution.

Another idea is that once everyone is driving electric cars, at any given moment, you'd have certain percentage of them connected to the grid charging thus creating a huge grid connected battery.  'Smart' metering/chargers could mean that if your car is fully charged, but sat there overnight say (or outside the office during the day), you might be able to 'lend' some electricity back to the grid.

Online Fulk

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Re: Deep Mine Shaft Required
« Reply #32 on: August 30, 2019, 01:26:22 pm »
Thank you SamT; you are right, but I think that what I meant by 'use' was 'runs at a rate of'.

Online SamT

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Re: Deep Mine Shaft Required
« Reply #33 on: August 30, 2019, 03:11:18 pm »
 :thumbsup:

kWh is a much better unit to use when talking energy use.  Joules are all a bit old fashioned and cumbersome and kWh are the unit used by utility companies. 

2000kg x 250m x 9.81 (gravity) x 0.7 (efficiency) = 3,433,500 kJ = 953.75 kWh.

Average house use is very hard to establish, but lets say 10kWh a day. = ~95 houses (but that is to supply all their energy for one whole day).

(think I've got my units right  :-\)

As I say, the system is not really designed to work in that way, and it bugs me when the media always revert to saying - can power 500 homes etc.  (though granted,  it does give a very rough idea of magnitudes and orders of scale).
« Last Edit: August 30, 2019, 03:36:43 pm by SamT »

Online Fulk

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Re: Deep Mine Shaft Required
« Reply #34 on: August 30, 2019, 04:11:41 pm »
You're obviously more tuned into this than I am, Sam – still, doesn':

2000 kg x 250 m x 9.81 x 0.7 equal 3433.5 kJ?

Online SamT

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Re: Deep Mine Shaft Required
« Reply #35 on: August 31, 2019, 08:26:42 am »
Well.. yes.  But convert that to kWh and you only get 0.93 kWh.

My gut instinct is to question that as it really does bring into question the worthiness of the concept

(I think I was trying to be optimistic before and assumed I was a factor of a 1000 out)

Now I'm confused.

Offline Boy Engineer

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Re: Deep Mine Shaft Required
« Reply #36 on: August 31, 2019, 10:13:34 am »
Quote
(I think I was trying to be optimistic before and assumed I was a factor of a 1000 out)

You are. They are talking about a 2000 tonne mass, not 2t. You’ve used 2000kg.

Online Roger W

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Re: Deep Mine Shaft Required
« Reply #37 on: August 31, 2019, 11:49:34 am »
A 2000 tonne mass is a rather large chunk of whatever...  254 cubic metres of iron, according to a conversion program I googled, or 176 cubic metres of lead.  And it's going to need some pretty hefty cables and pulley wheels to support it.
"That, of course, is the dangerous part about caves:  you don't know how far they go back, sometimes... or what is waiting for you inside."   JRR Tolkein: "The Hobbit"

Offline Chocolate fireguard

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Re: Deep Mine Shaft Required
« Reply #38 on: August 31, 2019, 02:27:21 pm »
:thumbsup:
 Joules are all a bit old fashioned and cumbersome
You kids don't know you're born!

Think yourself lucky you never had to use the erg, young man.

Or the slug rod squared/fortnight squared for that matter.

Offline droid

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Re: Deep Mine Shaft Required
« Reply #39 on: August 31, 2019, 06:01:42 pm »
If it's a mineshaft, shouldn't it be fathoms?
No longer 'Exceptionally antagonistic' 'Deliberately inflammatory'

Offline PeteHall

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Re: Deep Mine Shaft Required
« Reply #40 on: August 31, 2019, 09:04:42 pm »
I wonder if such a system could be built into an active mine shaft. Boulby is bloody deep (forget the exact figure) and the new Sirius Minerals one is something like 1.5km deep...
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Offline Graigwen

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Re: Deep Mine Shaft Required
« Reply #41 on: September 01, 2019, 06:58:57 pm »
If it's a mineshaft, shouldn't it be fathoms?

The fathom is a pretty handy historical unit in the UK, and when you are familiar with using fathoms they are easy to visualise. However in the modern day they generally lead to confusion as most people are not familiar with them and they are always inconvenient when calculating gravitational potential energy as you have to do an extra conversion step.

Years ago when I worked for a large Canadian mining corporation re-evaluating some Welsh mineral prospects, we had to be careful to avoid using metric units in material we sent to Canada as the corporation worked withj Imperial units only. I sent a load of geophysical and geochemical surveys (in feet, yards and miles) accompanied by mine plans and sections in fathoms and yards. The response was a baffled enquiry about "fms" which they did not understand.

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Offline Graigwen

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Re: Deep Mine Shaft Required
« Reply #42 on: September 01, 2019, 07:45:15 pm »
:thumbsup:

kWh is a much better unit to use when talking energy use.  Joules are all a bit old fashioned and cumbersome and kWh are the unit used by utility companies. 


Joules are not at all old fashioned, they are the SI unit for energy. The SI unit for power (i.e. the rate of energy conversion) is the watt, which is just another way of saying one joule per second.

The kWh is an old fashioned unit still used by some utility companies, largely for historical reasons as British consumers are used to it. The kWh is cumbersome to use since it contains time twice, once in the form of the SI unit for time the second and also in the form of the non SI unit the hour. As the energy (in other words joules) is both divided by time (seconds) and multiplied by time (hours) the kWh is just a clumsy way of stating a certain amount of energy and is therefore equivalent to a certain number of joules.

1 KWh  =  60 x 60 x 1000J  = 3,600,000J = 3.6MJ



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Offline Chocolate fireguard

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Re: Deep Mine Shaft Required
« Reply #43 on: October 21, 2019, 01:09:13 pm »
https://www.theguardian.com/environment/2019/oct/21/how-uks-disused-mine-shafts-plan-to-store-renewable-energy
Doesn't contain much more information.
Does contain the usual mashup of units but at least doesn't talk about massive weights.


Offline Chocolate fireguard

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Re: Deep Mine Shaft Required
« Reply #45 on: October 21, 2019, 09:58:00 pm »
?

Offline notdavidgilmour

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Re: Deep Mine Shaft Required
« Reply #46 on: October 22, 2019, 10:55:49 pm »
Pen y bryn is 800 ft

It's well 'n' truly capped and hidden though  ;)
I do it because i can, I can because I want to, I want to because you said I couldn't.