Jim & Hoyt...
I have to admit, that for as long as I have lived in Virginia I have never heard of Duck Pond Mills. So I did some searching (not quite researching) and all I could find was that the Michigan Cavalry referred to the engagement by several names: "Beaver Pond Creek," "Beaver Bend Creek," "Beaver Creek Pond," and "Tabernacle Run" (as well as Duck Pond Mills) - all listed as April 4, 1865. See the link below.
I would say it was more of a skirmish after the breakthrough at Petersburg. I would certainly love to know more about it myself.
John