figure out what this means:

"Once in service they realized that since the material being drilled is so much denser ( and heavier) at these greater depths, the drills do not have the capacity to lift it out of the hole. This then creates a second problem as the lab they are using has everything calibrated to process material of much less density"

Now what do you think denser rock could mean? What happens to the relative weight of mineralized rock when the concentration increases significantly? How terrible would it be to find out that we've hit such a dense find that we have to adjust, retool, recalibrate to accommodate something that will bring great returns with a little added time? Certainly it is possible that the rock is simply denser due to the increased pressure, but that may not be the sole reason.