Excelsior Mining Corp (EXMGF)

[tootalljones]

Recoveries Per World Nuc Association between 60 to 90%, and we have an ideal (per management) hunk of ground for this method. Does our study (48%) have a lot of buffer in it?

"...ISL uranium mining was first tried on an experimental basis in Wyoming during the early 1960s. The first commercial mine began operating in 1974. Today virtually all Kazakh and Uzbek, and most US uranium production comes from ISL mining. Several projects are licensed to operate there, (in Wyoming, Nebraska and Texas) and most of the operating mines date from the 1990s. They are small (under 1000 t/yr) but they supply most of the US uranium production. Russia’s Khiagda mine is ramping up to 1000 t/yr.ISL can also be applied to other minerals such as copper and gold.Uranium deposits suitable for ISL occur in permeable sand or sandstones, confined above and below by impermeable strata, and which are below the water table. They may either be flat, or "roll front" – in cross section, C-shaped deposits within a permeable sedimentary layer.Such deposits were formed by the lateral movement of groundwater bearing oxidised uranium minerals through the aquifer, with precipitation of the minerals occurring when the oxygen content decreased, along extensive oxidation-reduction interfaces. The uranium minerals are usually uraninite (oxide) or coffinite (silicate) coatings on individual sand grains. See also Appendix. The ISL process essentially reverses this ore genesis, in a much shorter time frame.There are two operating regimes for ISL, determined by the geology and groundwater. If there is significant calcium in the orebody (as limestone or gypsum, more than 2%), alkaline (carbonate) leaching must be used. Otherwise, acid (sulfate) leaching is generally better. In this case the leach solution is at a pH of 2.5-3.0, about the same as vinegar. Acid leaching gives higher uranium recovery – 70-90% – compared with 60-70% for alkaline leach, and operating costs are about half those of alkaline leach.Techniques for ISL have evolved to the point where it is a controllable, safe, and environmentally benign method of mining which operates under strict operational and regulatory controls. Due to the low capital costs (relative to conventional mining) it can often be a more effective method of mining low-grade uranium deposits." http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/mining-of-uranium/in-situ-leach-mining-of-uranium.aspx