Preparation Stir together bourbon and 4 teaspoons sugar until sugar is dissolved. Lightly crush mint leaves with remaining 4 teaspoons sugar in a metal bowl with back of a spoon until sugar is dissolved, about 5 minutes. Add 4 cups crushed ice, then add 3/4 cup bourbon mixture and stir well. Divide mixture among 8 (12-ounce) glasses with a ladle. Add enough of remaining 8 cups ice to almost fill glasses, then add remaining 3/4 cup bourbon and stir well.
Preparation Stir together bourbon and 4 teaspoons sugar until sugar is dissolved. Lightly crush mint leaves with remaining 4 teaspoons sugar in a metal bowl with back of a spoon until sugar is dissolved, about 5 minutes. Add 4 cups crushed ice, then add 3/4 cup bourbon mixture and stir well. Divide mixture among 8 (12-ounce) glasses with a ladle. Add enough of remaining 8 cups ice to almost fill glasses, then add remaining 3/4 cup bourbon and stir well.