During the summer of 1858, gold was discovered in the bed of the Zumbro River at Rochester and near Oronoco, creating a local sensation. On July 1, 1858, the Rochester Democrat reported that excitement over the discoveries remained unabated, that diggings at Oronoco were yielding two to six dollars a day per man, and that some ninety to one hundred men were at work. While little came of the boom in Rochester, the Oronoco Mining Company invested over $1,000 in sluices and a water wheel about five miles below Oronoco. The following spring, floods carried away the miners' handiwork, but prospectors rebuilt the installations and extracted enough gold to keep their hopes alive. A few months later, in July 1859, another flood demolished the works a second time, and that catastrophe, together with the hard times lingering from the great panic of 1857, exhausted the men's determination and resources so completely that the boom died overnight.