One thing that stands out in much of the Union planning for this attack ... everything will go fine if only there weren't a Confederate army in the field. We have a picture of Burnside readying his HQ to be on the move into Petersburg as soon as his corps sweeps to the top of Cemetery Hill and Ferrero's 4th Division goes double-time down the Plank Road into town. [cite]
One indication of this mentality is Hunt's sketch for 5th, 9th and 18th Corps artillery placement from the OR Atlas Plate LXIV, No. 3:
Taking just the north part of the full map, starting with batteries 14-18 from the 5th Corps (and #19, the southernmost 9th Corp battery), I've moved the legend to make way for Confederate gun positions.
Various reports show that the Confederates were aware of a mine somewhere on this front and preparations were made by Pendleton and the other artillery officers to have sufficient extra ammunition on hand, just in case. Even though only 3 divisions were left south of the Appomattox when Lee responded to Grant's gambit at Deep Bottom on 27-29 July, they were on full alert.
Sure, the Union generals cooperated fully to make a mess of the attack of the mine, they weren't alone on the battlefield.They did have the full attention of soldiers who were putting up a fierce defense of their home state and towns. Led by very capable men, William Mahone among them.