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Analyses of Pinchi Mercury Belt Limestones and Dolomites

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Sample Cals

BON elects sul ORO Te OOO 3.25 | 3.07 0.20

GW veveceece | 55.60 | 99.28 OMS Meetetsrs 0.07

TVOAM creleaeicie at RSE 5G di Oz et 33.01 | 27.97 1p}
(NagQ 1.08)

14@A......+-6 | 26-90 { 48.04 24.64 | 22.75 0.20
UODAV etelepelatele ors anes OS ily OOS TNT OUSSn Met eralets @.14
ZOOM oe toe mooMo ont Ona trees 0.27

Pure dolomite 30 64 54.35]
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cee cae nae erry ener we amen nen mtbr serene on me

Analyses by R. J. C. Fabry, Mineralogical Section, Geological Survey,
Canada.
33A. Buff, dolomitic limestone outcropping 5 feet from “south fault"
at Pinchi Lake mercury mine
69h. Blue-grey limestone sinister near office at. Pinchi Lake
- mercury mine.
110A. White, siliceous limestone Sxetane enables cinnabar from Finchi Lake
mercury mine.
140A. Buff, dolomitic limestone containing cinnabar from glory hole
at Pinchi‘Lake mercury mine.
192A. Buff. dolomite ince selelertis 10 feet from east fault on Kwanika
Creek.
200A. Buff limestone outcropping along ridge west of Kwanika Creek.
Most of thé serpentine outcropping along the Pinchi fault
zone has been altered to a buff, earbonate rock. In most places it is
made up of a network: of magnesite veinlets and quartz stringers from a
fraction of an inch’ ‘to 4 inches wide cutting Aan age gregate | of ankeritic
carbonate, cherty quartz, and mariposite. A féw veins of magnesite,
1 to 4 feet wide, were observed along the south face of Pinchi Mountain.
Irregular masses ‘of magnesitic carbonate up to 25 feet across and
veined by cherty quartz were also observed here. A rough analysis of
the ankeritic carbene ve is as follows:

WeCOn, 56 4%; Caco 5 216%.1%5) FeCO, s16..2%s
ae largely silica 12.0%.

BCONCHIC MINERALS
Mercury

Cinnabar occurs at many places within the Pinchi Lake
mercury belt, but the only known deposits of workable size and grade are
those of the Pinchi Lake mercury mine. Although the deposits oceur in
rocks of quite different character they all have been found in fractured
or porous rocks in or near the Pinchi fault ZONC TM

The main deposits at the Pinchi Lake mercury mine are found
.along or near faults cutting Permian sedimentary rocks. The cinnabar is
concentrated in brecciated zones along the faults as well as in partly
to completely dolomitized limestone ond in carbonatized quartzite, ribbon
chert, and schist cut by the faults. The limestone contains solution
cavities that range in size from mere pits to openings several feet across.
Many of these cavities are partly filled, mainly with calcite. Most of
the best ore in the upper part of the mine either fills openings “of this

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