As prospectors dispersed from Austin, several of them discovered rich placer sands located in what is now Elko County. It was in 1867, shortly after the Civil War, and one of the miners called the place Tuscarora to honor a Union gunboat on which he had served. Area underground deposits attracted some attention, but surface placer mining was the primary focus.

The U. S. Constitution requires the federal government to conduct a census every ten years. Enumerators used hand-written pages to record information on every person in the United States. Each census employed different questions, but certain inquiries remain the same. The Census Bureau publishes reports providing general overview of the data. These documents are available at libraries that are official repositories of federal government records.

Entrepreneur Adolph Sutro believed that a tunnel, excavated to intersect with the lower levels of the Comstock, would efficiently drain and ventilate the mines. After a failed early proposal, he incorporated the Sutro Tunnel Company with a legislative charter in 1865. His astonishing plan called for an excavation 20,489 feet or over three miles in length. It would climb one and a half percent from the Carson River Valley near Dayton, intersecting with Virginia City's mines at the 1,640-foot level.

Comstock mining began in 1859 with open pits at Gold Hill to the south and Virginia City to the north. Within months, the Ophir Mine pit at Virginia City's outcropping became perilously deep, forcing miners to excavate underground.

The Comstock challenged traditional methods of supporting mines with timbers assembled in an inverted "U." The decomposed quartz embracing the ore tended to fold itself around wooden supports, collapsing on excavations. In addition, the ore vein expanded up to sixty feet wide. A single timber supporting such a span would snap.