Cornell Mine, Texada Island, Nanaimo Mining Division, Vancouver Island, British Columbia, Canadai

Regional Level Types
Cornell Mine	Mine
Texada Island	Island
Nanaimo Mining Division	Division
Vancouver Island	Island
British Columbia	Province
Canada	Country

Northern Texada Island is underlain by Karmutsen Formation pillowed and massive basaltic flows with thick units of pillowed breccia conformably overlain by massive limestone of the Quatsino Formation, both formations of the Upper Triassic Vancouver Group. Various stocks and minor intrusions (Middle Jurassic) ranging in composition from gabbro through diorite to quartz monzonite, intrude the volcanics and limestones, and are locally associated with iron and copper- gold skarn mineralization. A major episode of folding (F1) has resulted in the limestones and, to a lesser extent, the underlying volcanics, being deformed into a series of broad, northwest trending open folds that plunge northwards. Three subparallel northwest striking lineaments are also recognized and coincide with the Ideal, Holly and Marble Bay faults. These faults cut a set of northeast striking faults. The Marble Bay fault, and to a lesser extent the Ideal fault, have apparently controlled the emplacement of some of the Jurassic intrusions and their associated skarn mineralization.
The Cornell occurrence area is underlain by bleached, massive recrystallized limestone of the Quatsino Formation intruded by the Middle Jurassic Cornell stock comprised of diorite and hornblende porphyritic diorite. Several porphyritic hornblende diorite dykes also occur. The Cornell mine is located on the Marble Bay fault which hosts the small Cornell stock which has been dated at 175 Ma (Open File 1990-3). Prominent east striking faults appear to be displaced by less continuous faults striking between 130 to 135 degrees near the Cornell shaft.
Skarn mineralization is associated with the contacts of limestone and diorite and porphyritic diorite dykes. Mineralization often forms irregular pipe-like bodies that plunge moderately, subparallel to the contacts between the limestone and intrusive rock. Garnet-diopside-calcite-epidote skarns are mineralized with bornite and chalcopyrite. Pyrite and magnetite occur in small quantities with rare molybdenite, tetrahedrite and native silver also present. These mineralized bodies are dominantly within the limestone but occasionally occur in diorite.
Several orebodies were historically exploited by underground development to the 110 metre level where the more important zones were named the Shaft, Coney, 4B, No. 8 and Glory Hole. Grades varied markedly from one zone to the next. Total production from 1897 to 1919 was 471,085 grams of gold, 2,194,471 grams of silver and 1,368,512 kilograms of copper from 40,687 tonnes of mined ore.

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Link to British Columbia Minfile:	092F 112

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References