The OLH showings are located on the west flank of Campbell Ridge, east of Hastings Arm on Observatory Inlet approximately 16.0 kilometres northwest of Alice Arm.

The occurrence is hosted in rocks of the Eocene Coast Plutonic Complex. Lithologies in the vicinity include medium grained equigranular granodiorite (quartz diorite), biotite granite, alaskite (quartz monzonite) and aplite-pegmatite.

Mineralization is developed in two zones, the North and South zones, about 2 kilometres apart. The North zone is at least 600 metres wide and the South zone consists of two showings which occur over a distance of 250 metres. Mineralization comprises molybdenite, pyrite, ferrimolybdite, iron oxide with minor chalcopyrite and hematite. The mineralization occurs as fine films on fractures, as selvages along margins of veins, as disseminated flakes adjacent to veins and as fine-grained masses in quartz veins. The molybdenite is in or associated with, two sets of quartz veins. The most common set strikes 010 to 040 degrees, dips 36 to 63 degrees west and the veins range from 2.5 to 15.3 centimetres in width. Fractures are usually only pyritic. Hydrothermal alteration of hostrocks is evidenced by silicification and chloritization of biotite. Seven grab samples of representative mineralization assayed 0.127 to 0.504 per cent molybdenum (Assessment Report 8361).

In 1979, the molybdenite showings were discovered by Noranda Exploration as a result of the release by the British Columbia Ministry of Energy, Mines and Petroleum Resources of analytical data obtained from samples collected during the 1978 Accelerated Geochemical Survey in the Terrace-Nass area. In 1979, Noranda conducted prospecting, geological mapping and geochemical surveys. In 1980, Noranda established a 52.8 kilometre control grid and collected 631 soil and 51 rock samples, and conducted geological mapping.