For some additional information, this Fort was in the upstate of the colony of South Carolina and was built in 1753 and abandoned in 1768. The primary source i'm referring to comes from the letters of a major local planter and later American Revolutionary:

"The service hinted at some time ago....was the compleat rebuilding of Fort P. George, with intire New barracks & Store Houses, a New Stone Well, one New Magazine, etc. This was very heavy work in that Country, but it became absolutely necessary....& it was by great Labour & application of 150 men and upward, constantly at work for the space of a month or six weeks perfected under the inspection of Capt. [Richard] Dudgeon, Engineer..... This work could not have been carried on without the protection & cover of a considerable body of Troops & it was done at this favourable opportunity by particular advice & desire of the Governor, & notwithstanding His Honour expected & pointed out no other hands for the Labour but the Negro Pioneers & the Provincial Regiment. Col. Grant was too much of a Soldier & was influenced by principles too equitable to throw the burthen upon the shoulders of those poor, naked, deserted and deserting fellows...

The prospect of that heavy jobb did in the circumstances of those poor fellows cause some of them to despond & at all hazards face to the right about. Even the Blackies made some attempts to shun this disagreeable "branch of the trade" & had established regular sick days. But had that note from the Lt. Governors Letter been circulated & the Provincial Soldiers found that the Negroes & themselves were intended for Beasts of Burthen I am very certain that in a short time few or none would have remained on the spot but such as were too sick or lame to Leave it."