The Vicksburg Mine
Given the closeness of the opposing lines and the very hilly terrain at Vicksburg, it is not surprising that enterprising Yankee engineers determined to dig a tunnel (or mine) under Confederate lines in an attempt to blow them up. The objective chosen for the mine was a strong Confederate position guarding the main Jackson Road. It was garrisoned by the 3rd Louisiana Infantry of Hebert's brigade, Forney's division, and so was known as the 3rd Louisiana Redan or the Great Redoubt. The lines opposing the 3rd Louisiana Redan were held by Leggett's brigade of Logan's division, XVII Corps. The center of their position was on a hill occupied by a large frame plantation house owned by the Shirley family (this remarkable house was struck numerous times by musket and cannon fire, but still stands today.) On 23 May Leggett's men started digging a zigzag approach trench that began 150 feet southeast of the White House (as the troops called the Shirley home). From here it snaked towards the Confederate line 400 yards to the west. The Union troops labored in 150 man shifts day and night in their sap or approach trench. Other troops were assigned to gather wood and make gabions and fascines to protect the diggers. Gabions were large cylindrical baskets of brush, while fascines were long bundles of bound brush. These were placed next to new positions and could be covered with dirt in order to shield troops from incoming fire.
The best progress in advancing the sap took place under the cover of darkness. Day workers were engaged primarily at