Continuing their attacks, the Union Army under Grant began their third offensive against Richmond-Petersburg. General Winfield Scott Hancock's II Corps and two divisions of General Philip Sheridans cavalry crossed the James River at the "Deep Bottom" oxbow. They crossed at night to threaten Richmond. The plan called for the infantry to push the Confederates to the west. Then the cavalry could attack the railroad that connected Lee to the Confederate army under General Jubal Early still in the Shenendoah Valley. Sheridan's cavalry was then to attack Richmond if possible. But after breaking through the Confederate line, the Union offensive stalled. The Union cavalry was counterattacked by Richard H. Anderson's Confederate infantry. But the counterattack was defeated by the dismounted cavalry with their Spencer repeating carbines. But late on July 28, Hancock and Sherman withdrew back to Deep Bottom. The next night, July 29/30, they crossed the James River back to their own lines. They left a garrison to guard the crossing at Deep Bottom. Both sides could claim a victory. The Union forces defeated the Confederate infantry at Darby farm. But the withdrawal afterwards allowed the Confederates a victory. It was a Union victory strategically because their attack on the Virginia Peninsula caused Lee to move five and a half divisions north of James River. This weakened Petersburg leaving only four Confederate divisions to fight there. While Hancock and Sheridan were diverting Lee's attention, a mining operation was going on at Petersburg. A long tunnel was being dug by a regiment of Pennsylvania coal miners. It was dug right up to a Confederate strongpoint.