The Monarch Mountain occurrence is located about 4 kilometres southwest of the community of Atlin.

The Monarch Mountain area is underlain by a large body of upper Mississippian to Permian Cache Creek Complex ultramafic rocks composed largely of variably altered peridotite. They may be coeval with the mafic flows of the upper Mississippian to Permian Nakina Formation of the Cache Creek Complex and emplaced as dikes and sills.

The asbestos occurrence consists of narrow veinlets from 3 to 6 millimetres wide composed of rather harsh, cross-fibre chrysotile material within serpentinite. The best showing comprises a 3-metre-wide zone with numerous parallel veinlets. Numerous other patches containing similar fibres are present in the area.

Several gold occurrences have been prospected in the area since the discovery of placer gold on Pine Creek and during this time the asbestos occurrences on Monarch Mountain were discovered. The showing received minor attention in 1950 and 1980. In the summer of 1950, twelve claims (Heli and Copter) were located on the asbestos discovery. In 1951, Helicopter Exploration Co. Ltd. made a geological survey of the claims and then dropped the Heli Nos. 5 and 6 and Copter Nos. 5 and 6 claims.