I'll Give This One Last AttemptVolcanic tuffs are blown out of volcanoes and deposited from the air. They are thickest near the crater rim but are affected by wind direction, wind velocity, and gravity. When they settle, they conform to the terrain upon which they fall, likely thicker where they fill in pre-existing depressions. Later on, faulting and subsidence can move blocks of rock around, including the tuff layers.
Sandra-Escobar is the erosional remnant of volcanics that collapsed into a caldera. This collapse ocurrs in the shape of a circular ring, after which the middle fills up with sediments. The outer ring of the caldera is visible in the video I posted of Cienega de Escobar. I think it is also visible on Google Earth. The Boleras deposit in in the NE quandrant of the collapse ring. It is therfore guaranteed to be faulted into pieces, with downward fault block displacement of blocks, towards the center of the caldera. This is all basic stuff.
Now the problem becomes a bit more unclear. What is the geometry, thickness and extent of the porous, lithic tuff? I can tell you one thing for sure: a 300 meter X 500 meter block of it with a 50 M sharp edge just did not fall out of the sky. From the cross sections on the REX website, we see that the tuff thickens towards the north. In all probablity, it should continue to thicken in the direction of the vent. But the fault block to the north appears to have sunk. This explains, in part, why hole #62 is so deep.
Another unknown is that, if they do find a thick section of porous tuff at depth, will it be mineralized as well? I think there is a very good chance of this, given abundant upwelling, mineralizing fluids moving up through the fractures in the caldera collapse ring.
But hey, if you don't like my theory and interpretation, just go and buy a known producer. They will probably all increase in price.