The Gold Drop occurrence is located on the south side of the Marmot River, 3.5 kilometres east of the Portland Canal and 8 kilometres south-southeast of Stewart.

A number of quartz veins and lenses are hosted in shear zones and occur in orthoclase porphyritic granodiorite of the Eocene Hyder pluton in the Coast Plutonic Complex. The shear zones and granodiorite are intruded by a few northeast and northwest striking, steeply dipping lamprophyre dikes. Two sets of veins generally strike 000 to 023 degrees and 050 to 070 degrees. Individual, well-defined veins vary up to 1.2 metres in width, and shear zones with poorly defined silicified walls containing numerous quartz veins and lenses are up to 6 metres in width. Mineralization generally consists of pyrite, pyrrhotite, galena, sphalerite, chalcopyrite and native gold in a gangue of brecciated quartz.

Several of the more important veins contain significant precious metal values. The Midas (Gold Pan) vein is up to 0.76 metre wide, strikes 008 to 050 degrees for at least 100 metres and dips 30 degrees west to 76 degrees east. A 4.414 tonne sample of sorted ore assayed 80.2 grams per tonne gold, 147 grams per tonne silver, 0.2 per cent copper, 2.0 per cent lead and 0.2 per cent zinc (Minister of Mines Annual Report 1946, page 84).

The Mystery (Pan Handle) vein strikes northward 010 to 170 degrees for 137 metres and dips 35 to 75 degrees west. The vein varies from a single solid quartz vein to a shear zone, up to 1.5 metres wide, of crushed quartz lenses and brecciated granodiorite. A 0.15 metre channel sample assayed 8.26 grams per tonne gold and 276 grams per tonne silver (Minister of Mines Annual Report 1929, page 93).

Production in 1936 totalled 1 tonne of ore with an average grade of 187 grams per tonne gold, 218 grams per tonne silver, 0.3 per cent copper and 0.5 per cent lead.

In 1929, work was done on this ground by the Bi-Metallic Syndicate and in 1938 by Crusader Mines, Limited. From time to time small shipments of hand-sorted ore have been made. Gold Drop Mines Limited acquired the property in 1944, and additional claims were staked. Development work by this company includes some stripping and 169 metres of crosscutting and drifting. The main underground workings consist of a crosscut 93 metres long, driven due south, and a drift from this crosscut which follows a fault zone for 71 metres in an average direction of 250 degrees azimuth. The zone contains several narrow stringers and one quartz lens having a length of 45.7 metres and a maximum width of 0.61 metre. The drift ends in a dike of uncertain attitude into which the vein-fracture continues.