PCV is on Natural gas main pipeline coming from fields. Distance is from field to processing facilities around 175 km. main trunk line is 30 inches dia.
Carryover quartz? from the well sand debrie itself, or it may have been introduced as proppant glass or ceramic beads during fracking. Its a bit far from the field, but not impossible to see it, especially if producing gas at a high rate through underdesigned separators.
--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."