 Although the Union troops failed again at Laurel Hill, an innovative assault attempt by Col. Emory Upton against the Mule Shoe showed promise.Grant used Upton's assault technique on a much larger scale on May 12 when he ordered the 15,000 men of Maj. Gen. Winfield Scott Hancock's corps to assault the Mule Shoe.Hancock was initially successful, but the Confederate leadership rallied and repulsed his incursion.