Lately, I have been pondering the resurgence of Tin Prices and what that means for potential activity in the future.

I have read a fair bit about the estimation of deposits via various methods, historical data, old plans as well as drilling and chemical analysis.

I am aware of the various projects and the recent interest in various deposits.

My opinion differs from many about the future of mining (that lower grade, larger deposits will be the way of the future) primarily due to the likely cost of milling huge amounts (energy costs). So, I wonder at what point focus will be directed back to previously worked high grade "unfinished" projects and what engineering challenges will face the people undertaking such a challenge. (Rather like the challenge of re-opening Crofty).

Clearly, a fresh prospect starts off with a hole, which eventually gets bigger/deeper and the pumping gear gets progressively more extensive and spectacular in an evolutionary manner.

I wonder how it would be approached and what considerations would be made/required by a company opening a flooded working.

Due to the plethora of information from Lean's Tables and Bradford Barton books, it would seem quite viable to estimate the cost of pumping a mine via using a Beam Engine, Cornish Pit work and the price of coal/shipping/transport. I imagine one could approach the costing quite accurately by looking at the size/efficiency/SPM and calibre of pitwork/depth of working by old tables and get busy.

I wonder if there is a parallel between the approach of the old men to mining "There is a lode, it's likely to be a good one, let's start a mine" and today's drilling after drilling after drilling after calculation after resource estimation after more drilling, fussing, modelling and debating. I wonder if hydrogeological models and all sorts of fussing are done regarding the sort of factors likely to influence the pumping requirements, or whether they just whack a pump in, wire it up and press the start button.

I am specifically interested firstly in the rough calculations regarding equipment specification and costing estimations, to more accurate models.

Clearly, there is a procedure for estimating the extent and proof of a mineral resource. There also must be a sort of means of estimating the pumping costs.

NB:- I am not maths adverse!

Discuss. Stu

Hi Stuey, enter the following in a google search.......

mining pumping efficiency


On the return list click on the googlebooks one entitled Underground mining methods:engineering fundamentals

It should take you to an article on the subject.

Lozz.

Going off an abandonment plan,a rough guide to the volume of water in the workings,versus the pumping ratio of the type of pump needed,versus power intake x kw charge

Of course the make of water,could alter pump size needed.

In a working Smallmine{Coal}with water problems,pumping costs would generally be 1/3rd of overall costs
One Colliery working in the 80`s,pumping 24hrs,costed 8pounds per ton of coal mined,at least 3 times the cost today.

Cheers Lozz, I will do that in due course.

I obviously figure that if you took a mine like Crofty and decided to pump it out to the bottom, (we'll imagine that the pumps are installed at the bottom and the pipes offer virtually no frictional resistance) you'd start off with very little energy and the whole workings would be drained at a rate proportional to their area (obviously). The loading of the head gradually becomes more and more of a significant factor until it is one of the key factors....I suppose it would be dependent on the sort of impeller used and how that was suited to the duty....rather like boat props...high speed vs big head......

I imagine that you could consider the power calculation by the mass x distance, etc. I imagine it would be way off the mark because it's not an ideal system.

I wonder what the approach is. There has to be a system where there is a calculation and then a worse case scenario factor, or whether a rough estimate is made and then expanded upon to allow for extreme weather....

I thought about Wheal Concord and wondered how they went about selecting the right sized pumps for the job.

I'll have a look at that article now.

Edit:- Cheers Lozz, that is exactly what I was after.

Edit again:- That's a bloody good book by the looks of it. £95 though.

There are pumping calculations and there are rules of thumb, you can work out by rule of thumb pretty easily using, the mass of water to be lifted, the height and the time and the apply an overall efficiency factor - for pump efficiency and system losses a sensible figure would probably be about 50%. Use a unit cost of electricity of about 8p/kwh (the sort of price large industrial users can get).

To work it out more precisely is a lot more difficult as you need to design your system first to establish the system losses, you then need to use the selected pump characteristics in order to work out the pump efficiency - this is the most important bit - choose the wrong pump and its going to cost twice as much to run as the right pump.

Interesting stuff. I'm going to work through a few rough calculations when I have a bit of time to draw a few parallels between old steam engines via lean's engine reporter stats and attempt to put a £ figure on a couple of them via today's energy costs.

Just like energy costs are likely to hinder low grades, it follows that energy costs would hinder low volumes. It's all very well saying that "Tin is £XXXXX a ton today" but I suspect that many places which Trounson hints at may still not be viable.

I have been trying to do the same with Lean's etc. Not surprising considering the amount of pumping that is planned.

A new mine, is probably easier to work with as there is a small amount of workings the volumes and inflows etc are all known or could be measured. Pumps are selected to match.

An old flooded mine is a whole new bag of worms. The major problems here are extent of workings - the plans and sections where they exist only give an indication of the areas where there might be tunnels and stopes. The sections give no indication of width of stoping and therefore it is very difficult to calculate with any degree of accuracy the volumes. In many cases there are no sections or complete sections so contingencys must be included in any calculation. So you now have a volume of water which you wish to pump out. So the math should be easy. Volume of water to be removed, the rate you wish to pump, the head you wish to pump against are all known or can be calculated. There is one variable not included is the rate of inflow. So as you pump the water will be inflowing at a rate that you will not know until you start dewatering. There is the cone of depression which also must be created and the size of that is also a little vague at the start.

The type of rock and location of crosscourses and other water bearing features also variable just to add to the mix.

See it now becomes more difficult and probably more expensive and take longer than you initially thought.

Perhaps this thread needs to be revisited once we have lowered the water in the mine next door to us. In doing this we will have answered most of the questions and perhaps we will have a better handle on some of the unknowns.

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Knocker,Agricola,
You both put it forward more eloquently than myself,but seems to be on the same lines,the intake Agricola mentions,being my make.
Depending on the age of mine you wish to pump,with the extent of you exploration you boys have done,width of roadways can be narrowed down as a good guide,regarding width of stopes,there seems a lot of info on this site of the veins worked in various mines in the area,so again a good guide.
The water bearing features Agricola mentions is a good point,Aquifers can hold vast amounts of water,were you notice very little progress when pumping,till these have drained,{wait for a dry summer like 2yrs ago}
If the volume of water you know about,requires a big pump,get one a size up,its cheaper in the long run.
Its only when pumped out,that you will know which size pump will keep the mine workable.

Pumping aside, tin processing/milling etc uses an awful lot of water.

Lozz.

So use the water pumped out, all you need is a reservoir.

Interesting point, a "pulse" pump ( as in Newcomen) can utilise flap valves in the pipe in lifting, an impeller pump(as in Flygt) would require storage reservoirs at the pumps lift limit, and multiple pumps, which one would be more efficient? discuss.

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Yes you can do if there is suitable land for water storage, I know from when I worked at Geevor that water for the mill etc was always operating on the edge despite U/G pumping of around 1.5 million gallons per day, I guess it depends on how wet the mine is etc.

Lozz.