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The Engineers at Vicksburg, Part 22: Union Sappers close in

U.S. Army Engineer Research and Development Center, Historian
Published June 8, 2017
Former lead miners from Missouri and Illinois excavated a gallery beneath the Confederate fortifications.

Former lead miners from Missouri and Illinois excavated a gallery beneath the Confederate fortifications.

Union soldiers converted a railroad handcar into a mobile firing platform to shelter those working on Logan’s Approach.

Union soldiers converted a railroad handcar into a mobile firing platform to shelter those working on Logan’s Approach.


Engineers in Union blue and Confederate gray played a prominent role in the Vicksburg campaigns of 1862-1863. Although their contributions have largely gone unnoticed in published works on the campaign, the stories of these men and the fatigue parties that toiled under their supervision are worthy of note and will be detailed in this series of articles.

Part 22: Union Sappers close in

From late May, through June, and into July, Union sappers labored on the various approaches that slowly extended toward the Confederate defenses. 

“Every man in the investing line became an Army engineer day and night,” recalled one veteran of the siege. “The soldiers got so they bored like gophers and beavers, with a spade in one hand and a gun in the other.”

The fatigue parties toiled day and night in the oppressive heat of a Mississippi summer behind a sap-roller which protected them from small-arms fire. Sap-rollers were large bundles of cane and vine woven together to form a barrel-shaped cylinder that was five feet long and ten feet in circumference. (Cane grows abundantly in the creek bottoms around Vicksburg and provided the Federals with an unlimited source of material for sap-rollers, fascines for revetment, and even shelter from the sun.) The cylinder was packed with dirt or cotton, anything that would stop a bullet. Once assembled, the sap roller was placed on the ground at the head of an approach and pushed forward by the sappers either by hand or use of poles. Behind the roller were men with picks and shovels sinking the approach who tossed the dirt out on the side closest to the enemy for lateral protection.

In the case of Logan’s Approach, however, a railroad handcar fitted with wooden wheels took the place of a sap roller. The handcar also served as a mobile firing platform as it was stacked high with 20 bales of cotton on top of which were logs loop-holed for riflemen. This unique device sheltered Logan’s men as they pushed the approach forward. In addition to the riflemen on the handcar were sharpshooters posted elsewhere along the line astride Jackson Road who laid down heavy and deadly covering fire.

The sappers closed quickly to within 300 yards, then 200 yards of their objective.

On May 29, pleased with the progress thus far achieved, Capt. Andrew Hickenlooper reduced the number of men in the fatigue party by one-third, but still the digging continued round the clock. By June 3 they had carried the approach to a commanding knoll, 130 yards east of its objective. Union soldiers quickly established an advance breaching battery on the knoll which was designated “Battery Hickenlooper.” Five guns were brought forward, including two powerful 30-pounder Parrott rifles, which soon pounded a breach in the earthen parapet of the redan.

Under the protection of the big guns, the energetic engineer resumed the forward progress. Due to proximity to the enemy, Hickenlooper further reduced the fatigue party to 100 men. By June 8, the sappers had closed to within 75 yards of the redan, and by the 16th were within a stone’s throw of their objective. But before the final push was made, he directed that a side trench be excavated south of and parallel to the Jackson Road. Union sharpshooters posted in this trench provided the necessary protection for the fatigue party which finally reached the redan June 22.

Early the next morning, 35 volunteers, all of whom were former coal or lead miners, began mining operations. Working in two shifts of three reliefs each, the miners dug a gallery that measured three feet by four feet into the face of the redan. The men who wielded the picks and shovels in these cramped conditions worked on their knees or even flat on the bellies, their efforts illuminated by the glow of candles. 

The sounds of digging were audible to the Confederates manning the Third Louisiana redan. Knowing what the Federals intended, the soldiers in butternut and gray grew increasingly desperate to stop them. 

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