Most of the North Walkerville had been swallowed by the Alice Pit by the time of its closure in 1960. Like its siter the Berkeley, the Alice Pit grew so much that it began consuming first houses, then entire neighborhoods. But about that same time, open pit mining began at the Alice here. The main pit was the Berkeley Pit, which opened about one mile southeast of here in 1955. Several "open pit" mines were created in the 1950s to maximize the amount of ore shipped to the processor. Ore minerals here included native silver (Ag), acanthite (Ag2S - silver sulfide), rhodochrosite (MnCO3 - manganese carbonate), rhodonite (MnSiO3 - manganese silicate), and sphalerite (ZnS - zinc sulfide).Īs mining technology improved the efficiency and viability of processing low-grade ore, copper mining entered a new phase.
The mine targeted the Alice-Rainbow-Black Rock Vein Systems. Seen here is the reclaimed Alice Mine (Alice Pit), which is in Walkerville, immediately north of Butte. In the supergene enrichment zone of the area, the original sulfide mineralogy has been altered. The copper mineralization has been dated to 62-66 million years ago, during the latest Maastrichtian Stage (latest Cretaceous) and Danian Stage (Early Paleocene). BQM rocks have been intruded and altered by hydrothermal veins containing valuable metallic minerals - principally sulfides. The Butte Quartz Monzonite ("BQM") formed 76.3 million years ago, during the mid-Campanian Stage in the Late Cretaceous. Butte Pluton), which is part of the Boulder Batholith.
The area's bedrock consists of the Butte Quartz Monzonite (a.k.a. The Butte Mining District has produced gold, silver, copper, molybdenum, manganese, and other metals. English: The town of Butte, Montana (pronounced “byoot”) is known as the “Richest Hill on Earth” and "The Mining City".