FROM THE LAST NR:

Further purification test work is underway to produce a potential range of purities that are required by end-users...

This is based on discussions with interested end users related to strict specifications under signed confidentiality agreements.
Once ready, the complete process flow sheet and associated engineering data will then be fed into the PEA which is now underway by RPA Inc. The PEA economic evaluation is substantially complete except for the final inputs from the purification test work. The final results of the metallurgical work and the subsequent PEA will be announced once completed.

"The engineering work completed to date has been much more detailed than is normal for a project at the preliminary economic assessment"

Just my take on it, but after re-reading the last NR, it states clearly that the PEA is substantially complete except for the final input of the purification #s. as stated above. I believe this whole process has been far more in-depth and demanding than a normal PEA.