Byron...I don't think a mine blast would be recorded with a double-couple focal mechanism (kind of meaning that there are 4 quadrants, two where the first motion is positive and 2 where it is negative) for strike-slip. I think the depth estimate was poor.....but by now if it was a mine blast it would have been either removed from the list, or flagged as such.
There was a tiny bit of science behind my foreshock comment...the Landers and Hector mine quakes were farther south, so I imagine they stressed the eastern California shear zone north of the ends of their ruptures (drove right-lateral faults in that area towards failure). On any particular Mojave fault there is a long average time between large quakes...5000 years or so....but that quakes are clustered into shorter active phases...like now...and GPS is showing rapid strain accumulation..
Chris