Ann: ACQUISITION OF HIGH-GRADE ARAXA NIOBIUM PROJECT, page-139

These are awesome @Paul88
In particular 11821-S-BA-RL-02-GE_r1 document.

Looks like the larger dam toe is ~50m from proposed pit edge (itafos design), and tailings are non-hazardous (explains why no water cover)
Downstream raise design which is good for global stability

"PAE (PAE_Araxá 26713) did not identify the necessary stability and dimensioning studies of the local and global slopes of the mining pit." = maybe an assumed pit wall angle? Unclear if this is geotechnically assessed likewise with the material strengths used in the analysis

Either way - at the proposed pit design dam and with those material strenghs (assumed?) used it appears to achieve required FoS in undrained seismic conditions though I'm not sure why they didn't model it with the water table at the spillway height i.e. fully saturated conditions with seismic which is worst case

What this higlights to me is:

• much more work needed (geotechnically)
• pit unlikely to be able to go much deeper in the central or eastern zone unless the tailings dam is moved or modified (as pit crest can't move much further east without impacting the toe)
• spillway would need re-designing and rebuilding to avoid any pit
• still too risky for me until this risk is more adequately addressed

I'd love to see the company put out a satellite image showing the dam and 50m setback and where that sits overlying the drillholes so that we can make an informed decision as to what implications the dam may or may not have on future potential development and make our own decision as to whether it forms a significant development impediment or not