Pilot Knob Mine, Pilot Knob, Iron County, Missouri, USAi

Regional Level Types
Pilot Knob Mine	Mine
Pilot Knob	City
Iron County	County
Missouri	State
USA	Country

An abandoned iron mine located 1.8 km (1.1 miles) ESE of Pilot Knob (city), just W of the surface outcrop, on federal Wildlife Refuge land (Pilot Knob National Wildlife refuge). The last mining episode was from 1968 to 1980, producing 20 million tons of ore averaging 35–40% Fe. Workings include underground openings.

Structure: St. Francois Mountains Footwall Porphyry Dips About 17 Degrees Sw Without Any Marked Undulations. The Beds Above The Contact Are Conformable.

Alteration: Sericitization, Silification, Hematitized

Tectonics: St. Francois Mountains

Deposit: Measurements taken along the footwall of the big cut: S 90 deg e, 15 deg S (west end of cut); N 63 deg w, 27 deg S (near middle of cut); N 35 deg w, 17 deg S (southeast end of cut). Both vertical and inclined joints are prominent. Conglomerate ore is nearly 200 ft thick in places. No one attempted to mine the boulder ore ( 1912 ). Ore also occurs in comparatively small veins of hematite. One strikes ne-s W and is vertical. Surface boulder and conglomerate ores constitute the most important ore reserves at pilot knob. Ore occurs in two beds. Upper ore bed ranges from 10 to 20 ft in thickness. The lower ore bed ranges from 5 to 30 ft in thickness. Conglomerate ore extends over 400,000 sq ft (estimated). Rocks on pilot knob are distinctly stratified near the summit. Beds have a dip about 13 deg sw. ; info.src : 1 pub lit

The Pilot Knob Mine was established in the 1850s as a source of “pig iron” ore. The ore was transported by the Iron Mountain Railroad to Carondelet, Missouri. Here the ore ended up at the Missouri Furnace Company (Dewey, 1891), a blast furnace, where the ore would be mixed with Connellsville or Illinois coke (Walker and Seaton, 1880).

During the American Civil War, the United States (Union) Army built a defensive fortification known as Fort Davidson in 1863 to protect the iron mines, including the Pilot Knob Mine, which was located less than a half mile from the fort. On September 27, 1864 the battle of Pilot Knob occurred where the fort now stands between the Union army commanded by Thomas Ewing Jr. and the Confederate army commanded by Sterling Price. For more on the battle, consult Foote (1974). The iron that was produced at this mine helped contribute to the Union war effort.

By 1910, the mining operation at the Pilot Knob Mine and nearby Shepherd Mountain Mine could no longer compete with the larger mines and became dormant in 1919. The Granite City Steel Company and the Hanna Mining Company organized the Pilot Knob Pellet Company in the 1960s and resumed mining operations at the Pilot Knob Mine in 1964. In May 1968, a concentrator and pellet plant were built (Carl, 2002).

In 1987, the Pilot Knob Mine became a 90-acre National Wildlife Refuge. The refuge is home to the endangered Indiana Bat (Myotis sodalis). The Indiana Bat was first discovered in the Pilot Knob Mine in the 1950s. In 1979 a partial mine collapsed killed the majority of the bat population. For more information on the bat population and the Pilot Knob Mine, see Elliot (2008).

Even though the mine was active at intermittent times, mineral specimens from this Missouri mine are relatively scarce. As the Pilot Knob Mine lies within a National Wildlife Refuge, it is closed to collectors.