Little Moose Creek mostly flows through Birch Creek Schist (Bundtzen, 1981). In the headwaters of Little Moose Creek, across the divide from an unnamed north fork tributary of the North Fork of Canyon Creek, a half-mile- wide band of siliceous and graphitic schist of the Keevy Peak Formation is downfaulted into the Birch Creek Schist (Hawley and Associates, 1978, fig. 4.1-A(2)). Below the outcrops of Keevy Peak Formation, ferricrete and limonitic spring deposits strongly discolor about 1500 feet of uppermost Little Moose Creek. A stream-sediment sample collected in Little Moose Creek about a mile below the limonite deposit and just above the placer mine contained 150 ppm copper, 65 ppm lead, and 1150 ppm zinc (Hawley and Associates, 1978, sample 62). A fault mapped immediately east of the placer mine places felsic schist of the Birch Creek against mainly calc-schist and quartzite-rich units. If this fault continues into the creek, it would be about at the head of the placer deposit.

The placer deposits occur in a narrow canyon with steep to moderately steep walls. The gravel section mined in about 1916 was about 8 to 10 feet thick, too deep for open-cut mining in the narrow canyon. Placer gold recovered was about 600 fine, shot-like in appearance, and accompanied by small nuggets of native silver (Capps, 1919, p. 93). Scheelite is a common mineral in the placer concentrates (Joesting, 1942).

Annual reports of the U. S. Geological Survey reported mining or active prospecting in many years between 1920 (Brooks, 1922) and 1933 (Smith, 1934). In 1922, Davis (1923) reported that miners cleaned 30,000 feet of bedrock at an average value of 22 cents per bedrock foot. Assuming that all of that value was due to gold (at $20.67 per ounce), the approximate production in 1922 was about 350 ounces of gold.