Monarch

Prospect, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Other commodities W; barite
Ore minerals chalcopyrite; galena; pyrite; scheelite; sphalerite; tetrahedrite; barite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale BC
Quadrangle map, 1:63,360-scale A-1
Latitude 56.00694
Longitude -130.0556
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Monarch prospect, in Section 2 at an elevation of about 2350 feet, is on a west-facing mountainside about 0.6 mile east-northeast of the Riverside mine adit (Elliott and Koch, 1981, p. 19, loc. 79). The location is accurate within about 0.2 mile.

Geologic setting

Geologic description

The country rocks in the area of the Monarch prospect are the Triassic Texas Creek Granodiorite, which underlies and locally intrudes pelitic metasedimentary and subordinate andesitic (greenstone) metavolcanic strata of the Jurassic or older Mesozoic Hazelton Group; the Eocene Hyder Quartz Monzonite, which intrudes the Hazelton and Texas Creek rocks; and still-younger Tertiary lamprophyre dikes, which cut all the other rocks (Smith, 1973, 1977; Koch, 1996).
The deposit (Buddington, 1929, p. 74-75; Byers and Sainsbury, 1956, p. 139) consists of quartz-barite fissure veins in granodiorite that contain local shoots of galena, pyrite, tetrahedrite, sphalerite, and chalcopyrite, and sparse grains of scheelite. Samples of one vein assayed about 1-1.5 oz Au per ton, and a specimen of tetrahedrite reportedly contained 266 oz of Ag and about 1.0 oz of Au per ton. Barite is locally an abundant constituent of the veins. Byers and Sainsbury (1956, p. 139) report that a quartz veinlet four inches thick and exposed for most of the length of a 30-foot drift contains an estimated 0.5-3.0 percent WO3. The veinlet may be part of the Olympia Extension (BC078) vein that crops out 1000 feet to the southeast.
Maas and others (1995, p. 254) suggest that the age of the Monarch deposit is Eocene, based on similarities in mineralogy, structural setting, and hostrock, to lead-isotope-dated Eocene deposits nearby in the Hyder district (see, for example, BC086). If so, the deposit is contemporaneous with emplacement of the Hyder Quartz Monzonite.
Geologic map unit (-130.05730432172, 56.006644580954)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Maas and others (1995, p. 254) suggest that the age of the Monarch deposit is Eocene, based on similarities in mineralogy, structural setting, and hostrock, to lead-isotope-dated Eocene deposits nearby in the Hyder district (see, for example, BC086). If so, the deposit is contemporaneous with emplacement of the Hyder Quartz Monzonite.

Production and reserves

Workings or exploration
The deposit was explored in the 1920s by opencuts, stripping, and a 30-foot adit.
Early assays of samples of one vein showed about 1-1.5 oz Au per ton, and a specimen of tetrahedrite reportedly contained 266 oz of Ag and about 1.5 oz Au per ton.
A quartz veinlet four inches thick and exposed for most of the length of a 30-foot drift contains an estimated 0.5-3.0% WO3 (Byers and Sainsbury, 1956).
Indication of production None

References