I'm unable to explain the official correspondence that contradicts your information as to Borland's physical presence.
As to the location of Lumpkins Mill; Holly Springs is only 30-40 miles from where I live. We've had picnics at Wall Doxey State Park, and fished several lakes and ponds in the area near where the mill was located.
Wall Doxey State Park can be found on highway maps along highway 7 from Holly Springs to Oxford.
This is just a few miles south of Holly Springs as indicated more precisely by the following:
The Old Mills of Marshall County
The South Reporter, 16 Apr 1998
By Hugh Henry Rather
When I was a young boy and later in my teens I heard much from my father, which my brother John Edward also heard, about the old water powered mills of Marshall County and particularly about Lumpkin's Mill that was built by our ancestor, great-great-great-uncle William Blanton Lumpkins, who came from Athens, Ga. In 1836 to settle in the area six miles south of Holly Springs.
Lumpkin's Mill was built in 1840 after W.B. Lumpkin had bought 4,000 acres of land from a Chickasaw Indian Chief. The mill was built just north of where Spring Lake is and where Wall Doxey State Park is now situated.
My father showed me the exact location of where the mill was before being burned by the Yankees in 1862. It was one of the largest mills in north Mississippi and was four stories high.