Lusk Creek Subdistrict
The mines and prospects of the Lusk Creek Subdistrict are aligned along the Lusk Creek Fault Zone, which generally marks the northwestern margin of the IKFD (Figure 27). Arranged in a line more than 4 miles long, all these mines and prospects share a common structural setting. The fault zone is 500 to 1,000 feet wide, is nearly linear, and has an overall trend of N 35° E. Parallel high-angle, southeast-dipping reverse and normal faults compose the fault zone. These faults delimit central slices of Mississippian rocks that are older than the rocks on either side of the fault zone. Two episodes of faulting are thereby indicated. First, compressional stresses induced reverse faulting that raised the southeastern block. Relaxation and extension then induced normal faulting that lowered the southeastern block below its original position, creating the Dixon Springs Graben (Weller 1943c; Nelson et al. 1991). Most of the mineralization took place along the reverse fault on the northwest side of the zone.
The most detailed information on mines in the Lusk Creek Subdistrict comes from a series of unpublished reports authored by J.M. Weller to characterize mineral deposits during World War II. Written while several of the mines were active, these reports include large-scale geologic maps surveyed by pace and compass.
Mines in the Lusk Creek Subdistrict
| Rock Candy Mountain, Moore, DeSautels, Tripod, and Williams Mines |
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| The Rock Candy Mountain Mine (Figure 27) was situated along the Herod Fault Zone close to its juncture with the Lusk Creek and Shawneetown Fault Zones. The name undoubtedly refers to the song “Big Rock Candy Mountain,” first recorded by Harry McClintock in 1928, which describes a hobo’s paradise “where the boxcars all are empty, and the sun shines every day.” Weller (1944a) conducted a detailed survey of the Rock Candy property while the mine was operational. Weller reported that a shaft was sunk in 1901 but was abandoned shortly thereafter. A Mr. McGowan reopened the shaft in 1932 and shipped about 100 tons of ore, but it was unmarketable because of the high silica content. The Big Creek Mining Company sank a new shaft in 1942 and shipped about 6,000 tons of ore over 2 years. The company’s operations continued through 1947 (Davis 1943, 1945, 1949; Davis and Greenspoon 1946, 1948).
The pace-and-compass map of Weller (1944a), at a scale of 1:2,400, located the Rock Candy Mountain Mine shaft 800 feet from the south line and 1,780 feet from the west line of sec. 25, T 11 S, R 6 E in Pope County. This location differs from that shown on the published geologic maps of Baxter et al. (1967) and Denny et al. (2008b). Because Weller surveyed for the map while the mine was active, we must consider his map and geologic interpretation more accurate than later renditions. However, additional excavations may have been made after Weller’s report in 1944. The vein at Rock Candy Mountain lies amid a series of narrow northeast-striking fault slices of Upper Mississippian limestone and shale and Lower Pennsylvanian shale and sandstone. The main workings of the 1940s consisted of a shaft that connected to a series of drifts and winzes. These accessed a vein striking northeast and dipping steeply southeast, with silicified sandstone in both walls. The vein ranged from zero to 21 feet wide, pinching out into brecciated sandstone. Veins of clear to purple fluorite contained clasts of sandstone, hence the high silica content. In 1982, John Nelson and Donald K. Lumm of the ISGS inspected an open pit at the mine site. The shaft had been backfilled and all structures had been removed. In the open pit, a fault surface striking N 45° E and dipping nearly vertical was well exposed, as were several subparallel fluorspar veins a few inches wide. The fault bore prominent near-vertical slickensides and mullion together with sandstone breccia. Several additional shafts and pits were opened, but these proved unproductive. In addition to the Rock Candy Mountain Mine, the Big Creek Mining Company sank several shafts nearby during the early 1940s. All except Moore proved unproductive. DeSautels ShaftThe DeSautels Shaft was located 1,490 feet from the south line and 2,300 feet from the west line in sec. 25, T 11 S, R 6 E. The shaft was reported to be 100 feet deep and encountered no significant mineralization. It is approximately 850 feet northeast of the Rock Candy Mountain Shaft at the junction between the northeast-striking Lusk Creek and north-trending Shawneetown Fault Zones. Moore ShaftThe Moore Shaft was located 200 feet due north of DeSautels, 1,690 feet from the south line, and 2,300 feet from the west line in sec. 25, T 11 S, R 6 E. The shaft entered a vein striking slightly east of north and dipping steeply east. Weller stated, “Several tons of spar were raised and sold,” and operations were continuing when he completed his report. Tripod ShaftThe Tripod Shaft was located about 375 feet northeast of Rock Candy Mountain, 1,080 feet from the south line, and 2,020 feet from the west line in sec. 25, T 11 S, R 6 E. A vein of fluorspar 6 inches wide was encountered at a depth of 40 feet, and apparently no production ensued. Williams ShaftThe Williams Shaft was located about 450 feet southwest of Rock Candy Mountain, 400 feet from the south line, and 1,570 feet from the west line in sec. 25, T 11 S, R 6 E. Weller (1944b) stated, “At the 75-foot level a drift was started southeast and driven for 20 feet, at which place a large flow of water was encountered, and the shaft rapidly filled nearly to the level of the collar.”
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| Lost 40 Mine |
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| Although a shaft was reported to have been sunk circa 1900, the main development of the Lost 40 Mine took place between 1940 and 1944. The Crown Fluorspar Corporation was the operator (Davis and Greenspoon 1946). Weller (1943c) completed a pace-and-compass survey of the property and made observations underground. Normal and reverse faults striking northeast and dipping steeply southeast outlined a slice approximately 500 feet wide in which upper Chesterian strata, including the Kinkaid Limestone, were faulted against Pennsylvanian rocks on either side. These observations infer reverse faulting that raised the southeastern block, followed by normal faulting that lowered the southeastern block. Mine workings comprised several open pits together with a shaft 130 feet deep and a series of drifts and crosscuts off the shaft. Above the 80-foot level, the vein varied from 3 to 10 feet wide and was composed predominantly of fluorspar. At greater depth, the vein pinched and swelled, reaching a width of 8 feet in places, although mud impeded Weller’s observations. The dip of the vein varied from 38° (unusually low for the district) to 73°.
Weller regarded the complex structure and abrupt termination of veins against faults as the primary obstacles to development. Poor road access was another issue. Evidently because of declining fluorite prices at the end of World War II, the Lost 40 was abandoned. Nelson and Lumm (1990) located the Lost 40 Mine during quadrangle mapping (Nelson et al. 1991, p. 60) and interpreted its structure in a cross section.
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| Ora Scott Mine |
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| The Ora Scott Mine was located 1 mile southwest of the Lost 40 Mine (SE¼ NW¼, sec. 10, T 12 S, R 6 E), and its structural setting was closely similar. Weller (1943d) carried out a pace-and-compass survey of the property, but underground workings were inaccessible and much of his information on them was secondhand. Weller reported that the site was first worked 40 to 50 years earlier (circa 1900) and that subsequently, operations continued sporadically under different owners. The Luella and McClellan Mines that Bain (1905) discussed are in this general area. From compiling various reports, Weller stated that “probably in excess of 1,000 tons of fluorspar” had been shipped. Two shallow shafts, two adits, and numerous prospect pits were observed when Weller inspected the site. As at the Lost 40, the Ora Scott Mine lay within a fault slice 500 to 700 feet wide in which upthrown Kinkaid Limestone and older Chesterian units were faulted against Pennsylvanian rocks on either side. Observed faults trended N 20°–40° E and dipped 65°–80° SE. The lack of continuity of orebodies and poor road access hampered development. |
| Gilbert Prospects |
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| Lucy and Raymond Gilbert opened several prospect pits along the Lusk Creek Fault Zone between the Ora Scott and Clay Diggings Mines (Figure 27) without finding significant mineralization. Weller (1943e) prepared a pace-and-compass geologic map of the property and assessed its structure and mineral potential. He observed little beyond outcrops of shattered and silicified sandstone indicating the proximity of faults. |
| Clay Diggings Mine |
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| Located on the northwest side of Lusk Creek just northeast of the Eddyville–Golconda blacktop, the Clay Diggings Mine took its name from vein deposits of halloysite clay that were mined as early as the 1860s (Engelmann 1866; Purdy and DeWolf 1907; Lamar 1942). Bain (1905) referred to this as the Pittsburg Mine. Weller (1944c) mapped the geology of the area by pace and compass. In addition to halloysite, this site yielded vein deposits of fluorite, sphalerite, and galena; limestone was also quarried. Bain (1905) and Weller (1944c) reported that the main halloysite deposit was a vein as wide as 8 feet along the reverse fault that bounds the northwest side of the fault zone. Excavations along this fault can still be viewed today. This fault is marked by deep red gossan, which is unusual for the IKFD.
Bain (1905) reported that the Pittsburg Mining Company had sunk two shafts and driven a drift and was erecting a mill to concentrate the ore. No definite records of later fluorspar mining have been found. During the 1930s, the Works Progress Administration operated a limestone quarry, and the quarry wall still affords good exposures. Clay Diggings exemplifies two episodes of faulting along the Lusk Creek Fault Zone. Two parallel faults approximately 300 feet apart outline a central block of Ste. Genevieve or St. Louis Limestone. These rocks are in fault contact with the upper Chesterian Degonia Sandstone, Clore, Palestine, and Menard Formations on the northwest and the Middle Pennsylvanian Tradewater Formation on the southeast. As Weller (1943c) deduced, the northwestern fault is reverse and the southeastern one is normal. Reverse faulting that raised the southeastern block was followed by normal faulting that dropped the southeastern block below its original position. |
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