a possible future...?, page-18

Early the KAS resource is at some depth (up to 600m). This statement from their May 2012 PFS:
"The March 2012 resource estimate was used to develop the PFS mine design. This design extends for 1,320m along strike and up to 600m below the surface, with mineralisation occurring within 60 vertical metres of the surface in the eastern part of the Meknes Trend".

CSD ore is reported to be generally from surface to a depth of about 50m.

KAS NPV values from their PFS were given as:
"Base case economic evaluation using a tin price of US$21,961/t delivers an after tax NPV of US$79M. The NPV rises to US$134M utilising the 2013 Consensus tin price of US$24,407/t."

Using these tin prices with my own most up to date CSD model I get similar NPV values as with KAS:
US$21,961 gives CSD NPV of $97 million.
US$24,407 gives CSD NPV of $144 million

If my figures prove to be reasonable it looks like CSD have more of an edge at lower tin prices.