The Grand Forks-Greenwood area is part of a well mineralized region of complex geology in the southern interior of British Columbia.
Lode mineralization was first recorded near Greenwood in 1884 and major deposits of copper and gold have been mined here since the turn of the century (Brock, 1903). Most of the mineral production from the Greenwood mining camp is from copper-bearing skarn deposits and, to a lesser extent, polymetallic quartz veins and, less commonly, copper-gold porphyry deposits. A more detailed breakdown of the area shows 12 vein-type producers related to granodiorite stocks, 4 vein producers in fault zones, 6 in skarns, 2 mineralized listwanites, 1 magmatic orebody and 1 porphyry copper deposit. Production to date from the 26 principal mines in the area stands at 32,044,173 tonnes of ore consisting of 38,278 kilograms (1,350,216 oz) gold, 183,102 kilograms (6,458,732 oz) of silver and 270,945 tonnes (606,916,800 lbs) of copper.
The Greenwood mining camp comprises more than 25 former mines, including the Phoenix mine, a world class open pit copper-gold skarn deposit; and similar smaller producers such as Mother Lode, Oro Denoro and Greyhound, and several significant polymetallic vein deposits, and more than 120 surrounding mineral prospects.
The combination of igneous intrusion, limestone and mineralization is repeated frequently throughout the camp, and there is little question that intrusion of the Jurassic and Cretaceous granitic plutons provided not only the thermal engine driving the circulation of mineralizing solutions to produce pyrometasomatic and porphyry-type deposits but these intrusions also provided the structural setting for the development of many vein fissures. A linear lead isotope relationship that connects diverse deposit-types in the area appears to be the result of fluid mixing within a well connected hydrothermal plumbing system.
The Phoenix ore body is locallized by faulting, the footwall argillite and impurity of the overlying limestone. No igneous source rocks are known, nevertheless, it is assumed that a deep seated granitic body under the mine area produced the mineralizing solutions which were then channelled by faults to favourable facies sites in the Brooklyn limestone for replacement and deposition.
Current exploration is focused on some of the oldest and youngest assemblages in the Greenwood area. Units of the Slide Mountain terrane, such as the Paleozoic Knob Hill and Attwood groups, hold promise for the discovery of stratiform polymetallic VMS-type deposits. Tertiary metallization includes epithermal Au-Ag veins, sulphur-poor silica sinter deposits and Carlin-type deposits with bulk tonnage potential.