Galena ore was discovered in 1885 while digging a well on the farm of Thomas D. Liles in November, marking the beginning of Aurora as a mining town. Mining of surface outcrops began in 1886. Large scale commercial mining began shortly afterwards as the mines grew deeper and zinc and galena were discovered. The zinc from the Aurora mines was of exceptional purity and high grade. By 1893, 12,651 tons of zinc ore were mined and shipped from Aurora. The mines attracted prospectors and miners. Aurora's population peaked at 10,000 "circa" 1900.