The Stonewall adit is located on Mine Creek, an east flowing tributary of the Coldwater River, approximately 5 kilometres north of the Coquihalla Lakes and about 1 kilometre south of the the old Keystone mine (092HNW024).

The Stonewall adit is situated near the western margin of an Early Tertiary quartz diorite (Keystone) stock which has intruded the Late Jurassic and Early Cretaceous Eagle Plutonic Complex west of its contact with Late Triassic Nicola Group rocks. The stock has an estimated area of approximately 1300 by 2200 metres. The southern half of the stock is brecciated, as is the older granodiorite adjacent to it. The brecciation has been attributed to the emplacement of small stocks and dykes of porphyritic rhyolite. This event was apparently accompanied by pervasive alteration and the introduction of metallic mineralization.

Little is known about the vein(s) developed in the Stonewall adit. It is reported to be narrow (5 to 10 centimetres wide), strike north-northeast and dip steeply. Sampled numerous times between 1939 and 1954, precious metal values were found to be generally low. The only assays of significance included several silver values "in excess of an ounce" (Assessment Report 18485, page 8).

Refer to the Keystone mine for further details of area geology and typical mineralization style.

In 1978, a rock sample (576A) from a lead-zinc bearing vein exposed on the north side of Mine Creek, approximately 150 metres west of the Stonewall adit, yielded 0.10 per cent lead and greater than 2.00 per cent zinc, whereas two samples (K18-1 and -2) from the Stonewall adit area yielded 0.315 and 0.410 per cent zinc, respectively (Assessment Report 6758 and 7135).

Work History

The area has been explored in conjunction with the nearby Keystone (MINFILE 092HNW024) occurrence and a complete exploration history of the area can be found there.

During 1946 through 1954, the area was sporadically explored by adits and trenching.