The east fork of Broxson Gulch drains fault-juxtaposed bedded rocks of the Slana Spur Formation of Late Paleozoic age and complex thrust slices of Upper Triassic ultramafic intrusive complexes (Nokleberg and others, 1991; W.T. Ellis, unpublished data, 1996). At this placer mine site near the Broxson airstrip (built since the publication of the 1978 edition of the Mount Hayes B-5 topographic map) a tributary creek drains a small fault-bounded wedge of Tertiary conglomerate (W.T. Ellis, unpublished data, 1996). This conglomerate may be the material mapped as a Quaternary fan by Stout (1976). The upper course of this tributary crosses the Airport Fault that also juxtaposes Upper Triassic ultramafic rocks and volcaniclastic strata of the Slana Spur Formation (Rose, 1965, figure 2); Nokleberg and others, 1991).

The placer workings are mainly at the mouth of the tributary to the east fork of Broxson Gulch, just north of the airstrip (built since the publication of the 1978 edition of the Mount Hayes B-5 topographic map). Equipment is scattered around the north end of the airstrip, and there is evidence that the gravel was bulldozed and run through a wash plant and sluice. Water was brought in by more than 2 miles of ditches. The main period of operation of the mine was probably about 1940 (Rose, 1965). The most recent mining occurred 3 miles to the south, at the west bend in the east fork of the stream in Broxson Gulch (W.T. Ellis, written communication, 1997). Production from this site was reported to be small, the gold very fine, and bedrock was not reached.