Empire Subdistrict

The Empire Subdistrict is located in eastern Pope County less than 3 miles west of the apex of Hicks Dome (Figure 14). The mines in this region have also been called the Empire-Knight-Douglas Group (Hatmaker and Davis 1938). Both surface and underground mines have extracted ore, which is predominantly fluorite, with only minor to moderate amounts of galena and sphalerite (Weller et al. 1952). Most of these mines exploited veins, but some bedding replacement ore was mined at the Gaskins, Pierce, Oscar Crabb, and Redd Mines. Weathered gravel spar was mined in fairly significant volumes in the Pierce and Slapout Open Cuts. The mineralized veins appear to be mainly along normal faults with slight to moderate displacement. The faults strike predominantly northeast to east-northeast, with some merging to the southwest. These faults may be radial fractures created by the vertical uplift at Hicks Dome, but some may also be related to the extensional forces that created the Dixon Springs Graben. Baxter et al. (1967) mapped a semicircular fault along the east side of Grand Pierre Creek, which is a northerly extension of the fault mapped by Weller et al. (1952). This fault is concentric, oriented west of Hicks Dome, and extends northeasterly toward the Hamp Fault. Geologic mapping in the Gaskins Mine indicated that left lateral movement was present along with dip-slip displacement. Information on several of the larger mines was taken from an unpublished report by Weller (1943b), who prepared a pace-and-compass map of the subdistrict at a scale of 1:4,800 showing mines and prospects, veins, faults, and other geologic information. The prospects and mines of the Empire Subdistrict are discussed from north to south.

References

Baxter, J.W., G.A. Desborough, and E.W. Shaw, 1967, Areal geology of the Illinois Fluorspar District: Part 3—Herod and Shetlerville Quadrangles: Illinois State Geological Survey, Circular 413, map, 1:24,000; report, 41 p. and 1 pl.

Hatmaker, P., and H.W. Davis, 1938, The fluorspar industry of the United States with special reference to the Illinois-Kentucky District: U.S. Bureau of Mines, Bulletin 59, 128 p.

Weller, J.M., 1943b, Illinois fluorspar investigations, III. Outlying properties, B. Empire district: Illinois State Geological Survey, unpublished manuscript, filed under J.M. Weller, ms. 12-B, 44 p.

Weller, J.M., R.M. Grogan, and F.E. Tippie,1952, Geology of the fluorspar deposits of Illinois: Illinois State Geological Survey, Bulletin 76, 147 p.