The studies of fluorspar localities in Utah made by the U. S. Geological Survey during and since the recent war are summarized. The fluorspar at the
Cougar Spar and Blue Bell mines in the Indian Peak Range of western Beaver
County occurs as fissure veins in fault and breccia zones in volcanic and intrusive rocks. At the Monarch (Staats) claims in west-central Beaver County
fluorspar was mined chiefly from a fault between limestone and rhyolite
porphyry. The Thomas Range district in Juab County has yielded sizeable
tonnages of fluorspar from pipes in faulted dolomite and rhyolite porphyry.
From 1918 to 1924 the Silver Queen mine in Tooele County produced fluorspar
from flssure veins in faulted limestone.
The report describes the geology of producing mines and the various prospects
examined. Production and reserves of fluorspar for Utah are summarized.