a quarter to five in the morning of the 30th of July
The miners drove a gallery under the works , and then drove other galleries right and left under them . These were charged with eight thousand pounds of powder . When all was ready , masses of troops were brought up to take advantage of the confusion which would be caused by the explosion , and a division of black troops were to lead the assault . At a quarter to five in the morning of the 30th of July the great mine was exploded , blowing two guns , a battery , and its defenders into the air , and forming a huge pit two hundred feet long and sixty feet wide . Lee and Beauregard hurried to the scene , checked the panic that prevailed , brought up troops , and before the great Federal columns approached the breach the Confederates were ready to receive them . The assault was made with little vigor , the approaches to the breach were obstructed by abattis , and instead of rushing forward in a solid mass they occupied the great pit , and contented themselves with firing over the edge of the crater , where regiments and divisions were huddled together . But the Confederate batteries were now manned , and from the works on either side of the breach , and from behind , they swept the approaches , and threw shell among the crowded mass .