City of Henderson Parks and Recreation Department marker reads:
Manganese ore was mined at this site from 1917 until the mine was shut down in 1961. Much of the manganese was mined during World War I to produce ferromanganese steel. In 1942, a pipeline from Lake Mead to the mine was constructed to enable milling of the ore on site for use in World War II.
Was located near current-day East Lake Mead Parkway and Lake Las Vegas Parkway in Clark County.