The Marmot Engineer occurrence is located near the headwaters of the south fork of the Marmot River, 12.5 kilometres southeast of Stewart. The area is underlain by argillite, siltstone and sandstone of the Middle-Upper Jurassic Salmon River Formation (Hazelton Group) and the northeast flank of the Eocene Hyder pluton (Coast Plutonic Complex).

The occurrence consists of two main showings which occur in hornfelsed argillite just northeast of the granodiorite contact. At approximately 759 metres elevation, a 1.8 to 2.4 metre wide quartz breccia vein strikes 144 to 150 degrees and dips 65 to 80 degrees northeast. The vein is mineralized with pyrite, sparse chalcopyrite and trace stibnite.

South of the vein, at 945 metres elevation, various shear zones contain sparse lenses of quartz and calcite mineralized with sphalerite, galena and pyrite. One lens strikes 120 degrees and dips shallowly to the south.

In 1930, at about 914 metres elevation the showings have been explored by some cuts and tunnelling. At a lower elevation, a quartzose shear zone 2.1 metres wide striking 330 degrees and dipping 65 degrees north is exposed in an opencut and is sparingly mineralized with chalcopyrite and some specks of what appears to be stibnite. About 76 metres northerly from this cut and about 23 metres lower elevation, a tunnel driven in a semicircular direction to avoid coming out to talus, and now facing south, has been driven for 81 metres. The face of this tunnel is approximately at the projection of the zone on this level.

Granby Gold Inc.'s Marmot property, containing the Marmot Engineer, underwent geological mapping throughout 2013 to 2015. In 2017 the geology was finer tuned by interpretation with regional airborne geophysics and again in 2018 with airborne geophysical survey data.