Mining and mineral development has had lasting effects on Little Cottonwood Canyon. The railroad to Alta was constructed in 1875. The line was built from the mouth of the canyon to Tanners Flat in about two months, accelerated by the availability of Chinese laborers left idle by completion of the transcontinental railroad at Promontory Point in 1869, and the complete absence of environmental regulations or employee safety laws. The current road follows much of the rail line.

Although millions of tons of ore were mined from Alta, today there is almost no evidence of this mining activity. Most of the ore at Alta was high grade silver-bearing galena (lead sulfide) with a relatively small proportion of lower grade material. The residue of mining was largely removed by the massive floods of spring. It all went down the creek.

The underground workings of the Bay City Tunnel drift off into oblivion.