The Granby occurrence is located on a west facing slope, east of Allison Creek and approximately 2.5 kilometres north of the creeks’ junction with the Similkameen River.
This area in the vicinity of Mount Miner (Baldy Mountain, Allison Mountain) is underlain by the eastern facies of the Upper Triassic Nicola Group, consisting of mafic augite and hornblende porphyritic pyroclastics and flows. These rocks are intruded by small dioritic bodies that may be coeval with the volcanics. A fault striking northeast along Dear Valley Creek (Deer Valley fault) juxtaposes the volcanics against coal-bearing sandstones and shales of the Eocene Princeton Group to the northwest.
Locally, a zone of porphyry-style copper-gold mineralization, largely hosted by microdiorite but also by variably altered Nicola volcanics, has been identified. The northern half of the Granby Zone is underlain by a medium-grained magnetic, pyroxene diorite which is most likely comagmatic with the Nicola volcanic rocks. The southern half of the zone is underlain largely by intensely fractured and altered Nicola volcanic rocks with subordinate amounts of microdiorite.
Two zones of crushed and deeply oxidized rock, 50 to at least 100 metres wide traverse the southern part of the Granby Zone in a northwesterly direction. These crush zones probably represent major faults and appear to be mostly in volcanic rocks. The main area of hypogene sulphide mineralization is found northeast of the two crush zones and consists of disseminations and fracture fillings of pyrite, bornite and chalcopyrite with rims of chalcocite and covellite in a saussuritized microdiorite. Nicola volcanic rocks are also variably mineralized but due to their generally more broken, altered and oxidized condition near surface, most commonly contain secondary copper minerals such as malachite, azurite and locally native copper.
The dominant alteration is propylitic (chlorite-epidote ± actinolite ± hematite ± albite± pyrite), but large areas of albitization (Na-feldspar), sericite/illite ± rutile, carbonate and potassic alteration (K-Feldspar ±Magnetite) have also been encountered by drilling.
Drilling has intercepted a large zone of gypsum-pyrite-albite-clay brecciation/veining which occurs at depth and appears to mark the lower boundary or outer boundary of the ‘better’ mineralization and metal grades.
In addition, historic drilling has indicated more mineralization and strong hydrothermal alteration at two other locations approximately 300 metres to the southwest and 200 metres south of the known zone of mineralization.
In 1965, copper mineralization, greater than 0.30 per cent copper, was reported to have been intersected in three percussion drill holes, while five other holes intercepted from 0.10 to 0.30 per cent copper mineralization (Preto, V.A. (2009-03-09): Review and Recommendations – Miner Mountain Project).
In 1973, a diamond drill hole (73-4), located on the eastern margin of the Granby zone, yielded 0.27 per cent copper over 70.2 metres (Preto, V.A. (2009-03-09): Review and Recommendations – Miner Mountain Project).
In 1997, drilling yielded intercepts of 0.115 per cent copper over 40.5 metres in hole 97-1 and 0.18 per cent copper with some gold-palladium values over 52.5 metres in hole 97-2 (Assessment Report 26296; Preto, V.A. (2009-03-09): Review and Recommendations – Miner Mountain Project).
In 2000, drill hole 00-1 yielded 0.252 per cent copper over the final 39.0 metres of the hole (Assessment Report 26296; Preto, V.A. (2009-03-09): Review and Recommendations – Miner Mountain Project).
In 2008, diamond drilling yielded intercepts of 0.46 per cent copper, 0.14 gram per tonne gold and 2.58 grams per tonne silver over 64.24 metres in hole MM-08-04 and 0.41 per cent copper, 0.12 gram per tonne gold and 2.11 grams per tonne silver over 52.47 metres in hole MM-08-09 (Preto, V.A. (2009-03-09): Review and Recommendations – Miner Mountain Project). Both holes bottomed in mineralization.
In 2009, drill hole MM-09-11 yielded 0.355 per cent copper, 0.165 gram per tonne gold and 2.52 grams per tonne silver over 62.79 metres (Preto, V.A. (2011-06-17): Review and Recommendations – Miner Mountain Project).
In 2010, a diamond drill hole (MM-10-19) located a new zone or extension of this mineralization to the south and west of the crush zones in similarly altered microdiorite, while trench 96 is reported to have successfully located ‘excellent’ grade mineralization above drill hole. Drilling highlights included intercepts of 0.31 per cent copper over 96.62 metres in hole MM-10-16 and 0.27 per cent copper with 0.16 gram per tonne gold over 60.41 metres in hole MM-10-19 (Preto, V.A. (2011-06-17): Review and Recommendations – Miner Mountain Project).
In 2011, percussion drilling yielded values of up to 1.264 per cent copper and 1.061 grams per tonne gold over 52 metres in hole PDH-09, 0.842 per cent copper and 0.834 gram per tonne gold over 26.0 metres in hole PDH-68 and 1.006 per cent copper with 0.576 gram per tonne gold over 82.0 metres in hole PDH-94 (Assessment Report 32369; Christopher, P.A. (2012-10-15): Technical Report on the Miner Mountain Property).
In 2012, diamond drilling yielded values of up to 0.95 per cent copper, 0.55 gram per tonne gold and 3.47 grams per tonne silver over 100.39 metres in hole MM12-21 and 0.34 per cent copper with 0.30 gram per tonne gold over 128.02 metres, including 2.46 per cent copper, 1.357 grams per tonne gold and 8.90 grams per tonne silver over 35.05 metres in hole MM12-24 (Christopher, P.A. (2012-10-15): Technical Report on the Miner Mountain Property).
Another zone of similar mineralization, referred to as the North zone, is reported to be located approximately 2 kilometres to the north- northeast. The North zone is underlain by a rusty white, intensely altered rock of uncertain origin with disseminated pyrite flanked to the north and south by sparse exposures of weakly altered and unmineralized volcanic rocks.
The area has been explored in conjunction with the nearby Regal (MINFILE 092HSE078) occurrence and a completed property exploration history can be found there.
