The Ogden Mountain occurrences are situated on the southwest slopes of Mount Ogden, approximately 40 kilometres north-northeast of Takla Landing. Nephrite boulders were initially discovered in the area in the late 1960s and efforts to locate their source(s) eventually resulted in the discovery of numerous in-situ nephrite showings (see Jade and Ogden Creeks (093N 156), Lee (93N 157)).
Variably metamorphosed sedimentary and volcanic rocks of the Carboniferous to Jurassic Cache Creek Complex are intruded by sill-like serpentinite bodies formerly assigned to the Middle Permian to Late Triassic Trembleur intrusions and now termed Mississippian to Triassic Oceanic Ultramafites, and rocks of the Late Triassic-Early Jurassic Topley intrusions, 7 kilometres west of the Pinchi fault.
The nephrite occurrences in the Mount Ogden area occur within a belt of ultramafic rocks and serpentinite melange informally referred to as the Cache Creek Ultramafic unit. The ultramafic unit is mainly serpentinite and serpentine-carbonate-talc schist with abundant "knockers" of green show, amphibolite and metasedimentary rocks. The eastern margin of the ultramafic unit is an east dipping thrust fault. The western rocks are a clastic sedimentary unit of the Sitlika assemblage.
An elongate stock of coarse-grained, two-mica granite cuts through the ultramafic unit. The contact between the two is a contact metamorphic zone. Locally, garnetite, marble, nephrite, and nephrite schist form at the contact. Nephrite also occurs along the tectonic contacts.
Discontinuous nephrite (tremolitic amphibole) bands and lenses occur at the contact of serpentinite and metasedimentary rocks. Colluvial boulders of nephrite are also widely distributed on the property. Nephrite also occurs as a steeply dipping vein-like zone at the contact of serpentinite and a leucocratic phase of a granodiorite sill. Accessory garnet, diopside, sericite, chlorite, and calc-silicates are associated with the nephrite zones.
The original Wire-Saw zone, from which 272 tonnes of nephrite has been mined, occurs at a serpentinite/metasediment contact. A large lens of nephrite occurs approximately five metres below the original lens. This lens, estimated to contain 36 tonnes of nephrite, is for the most part strongly laminated or fractured and only 4.5 tonnes was marketable. A pit above this zone intersected low-grade nephrite boulders and a large lens striking northeast into a hill. Four hundred metres southeast along the strike of the serpentinite/metasediment contact, trenching has exposed five boulders of low-grade nephrite.
At the Volcanic Ridge zone, along a serpentinite/volcanic contact, a large lens of nephrite measuring 8 by 7 by 2.5 metres is estimated to contain approximately 363 tonnes of "moderate quality" material.
At the New Jade zone, a steeply dipping band of high-quality nephrite, 25 centimetres wide, occurs at the contact of serpentinite and a leucocratic granodiorite sill-like intrusion. Indicated reserves are 374 tonnes, but only 10 per cent of this amount may eventually be recovered due to the narrowness and steep dip of the zones (Assessment Report 16737).
Numerous boulders of black nephrite have also been located in the area. North of the camp, two such boulders represent indicated reserves of 108 tonnes (Assessment Report 16737).
Total production of nephrite to 1992 from the Mount Ogden occurrences is estimated to be 1441 tonnes (Mining in British Columbia 1975-1980, 1981-1985, 1988; Kirk Makepeace (Jade West), personal communication, 1993 (production for 1989 to 1992)).
In 1992, Jade West Resources Ltd. conducted trenching and 500 metres of percussion drilling (Information Circular 1993-1).
In 2014, Green Mountain Gemstones Inc. shipped less than 5 tonnes of raw jade and 8 tonnes of high-grade jade from stockpiles. Claim owner Donald Bragg explored the northeast portion of the claim block. Boulders of nephrite jade were noted as a possible resource for Green Mountain Gemstones Inc., the placer claim holder. Despite this, no in-situ nephrite deposits were observed on this part of the Pinchi property.
In 2016, Green Mountain Jade Inc., a partner of the Jade West Group, resumed exploration and placer mining of alluvial nephrite boulders and excavation of nephrite from bedrock, with forecast production totalling 35 tonnes.
In 2017, only 20 tonnes were shipped of the 400 tonnes extracted.
