The Dan 48 fluorite prospect is situated in the Caribou Range in the Northern Rocky Mountains, 8 kilometres north of Grayling River, 88 kilometres west-northwest of Nelson Forks. It was explored by Frontier Resources Incorporated and Pan Ocean Oil Limited in 1972.
The Caribou Range is underlain by folded, mainly Devonian and Mississippian sedimentary rocks belonging to Ancestral North America (Geological Survey of Canada Map 1713A). The Dan Group of claims covers an east-dipping panel comprising the Middle Devonian Stone and Dunedin Formations, and the Upper Devonian to Mississippian Besa River Formation (Geological Survey of Canada Open File 673). A number of fluorite-barite showings of the vein or bedded replacement type occur in the claim group, all within the Dunedin Formation in a north-trending linear belt with a strike length of 8 kilometres. The northern half of this belt has been called the "Northern" trend, and the southern half the "Southern" trend (Assessment Report 4205). The Dan 48 prospect is near the centre of the Southern trend. Other showings in this belt are covered by MINFILE occurrences 094N 004, 094N 005 and 094N 006.
The Dunedin Formation consists of bedded, dark grey, fetid, argillaceous or siliceous (silty or cherty) limestone, and is about 260 metres thick (Assessment Report 4205). The uppermost 30 metres of the formation consists of dark grey limestone with numerous lenses and nodules of black chert. Like most of the other occurrences in the belt, the Dan 48 is in a 23-metre thick interval near the base of this upper, chert-rich subunit of the formation. In this locality, the mineralization consists of fine-grained disseminated fluorite forming a bedded replacement in pitted, sandy limestone (Assessment Report 4205). The limestone is cut by thin feeder fractures. The exposed mineralized zone is 15 metres long, 6 metres wide and 2 to 3 metres thick (Assessment Report 4205).
An assay was made of a composite sample from the Dan 48 and two other, similar bedded replacement occurrences in the belt: the Dan 32 (094N 004) and the Dan 6 (094N 005). The result was 53.4% fluorite (CaF2; by weight), 41.1% quartz, and 4.1% witherite (BaCO3), for a total of 98.6% (Assessment Report 4205).