Lets put to bed the debate on whether STB at colluli has superior potential to ELM in Congo.
The emotion Ive seen in most posts is amazing. They read like posts from Carlton & Collingwood fans slugging it out.
So lets objectively consider just the facts re the mining phase because the capex and opex cost differences between the 2 potential mines is so large as to dwarf the difference in the deposit sizes ? which is currently in STB favour.
STB deposit is a monolayer which 17 drill holes indicate has an average thickness of 19m at approx 60m deep and average 20% KCL.
Now, refer to ELM 22/12/10 report esp figs on P6&7 & text info (or their latest quarterly).
While ELM deposit has a higher potash content, the potash is distributed over a vertical depth of about 60m within 3 to 4 thin (0.6 ? 5m thick) layers over the interval 240 ? 300m below surface.
But each potash layer is separated by 5 ? 10 m of (nuisance) water soluble, halite (NaCl)and that is the problem posters are not considering.
If ELM were to go open cut to get all potash contained in all 4 layers, it would require removing 240m of overburden before they got to the first layer ? versus a max of 60m at Colluli.
Plainly, that cost for ELM would be at least 4 times more expensive than for STB.
OK. Thats the easy bit.
Mining via solution or conventional, would normally require leaving more than 70% of potash in the ground as pillars to support the roof to avoid cave in.
But the close proximity of each potash layer within the water soluble halite matrix makes the solution mining option horrendously complex.
This is because the presence of water soluble halite above and below each potash layer makes it impossible to selectively dissolve just the potash layer.
The roof and floor will also be dissolved with inevitable cave in problems.
Remember, this process is controlled remotely - at the surface.
I suspect that it is not fully appreciated that potash deposits are unlike gold etc in that the horizontal spread of such deposits extend for K not metres and roof support over such huge areas is the problem.
If you are new to this stuff, please don?t throw your money away by relying on biased info in many of these posts, do yourself and your investment funds a favour, go to an authoritive document on potash solution mining at around P80 at
