The Union soldiers in this section of the line
were commanded by Brig. Gen. John M. Thayer. They had taken part in the unsuccessful
assaults on 19 May and 22 May. During those attacks, Thayer's men had advanced up the hill
only to be driven back by Confederates positioned at the top. After the second setback,
the Federals began digging a six foot deep approach trench.
Once close enough to the confederate works on top of the
hill, it was intended to start a mine under the Southern position similar to the one being
dug under the Third Louisiana Redan. The men digging the approach trench were protected
from Confederate fire by bundles of cane called Fascines. They served as a roof on the
trench. Thayer's soldiers had begun digging their mine and nearly had it completed when
Vicksburg surrendered.
