| Lat / long: | 37.70339, -90.63344 |
| Primary: | Iron |
| Ore: | Magnetite, Martite |
| Gangue: | Actinolite, Andradite, Apatite, Barite, Bornite, Calcite, Chalcopyrite, Chlorite, Dolomite, Epidote, Fluorite, Galena, Pyrite, Pyroxene, Quartz, Sericite, Tremolite |
| Orebody form: | ONE OF THE MAIN ORE BODIES IS CRUDELY DOME SHAPED, THE OTHER IS AN ELONGATED LENSE IN PLAN BUT HOOK-SHAPED IN CROSS SECTION |
| Operation type: | Unknown |
| Production size: | Small |
| Development status: | Past Producer |
| First production started: | 1845 |
| Host rock: | Andesite Porphyry |
| Host type: | Conglomerate,Andesite |
| Associated type: | Andesite |
| Structure: | St. Francois Mountains, Ozark Dome., Many Near-Vertical Strike-Slip Faults Intersect The Ore Body, But Most Have Displacements Less Than A Foot. Faults Are Especially Common Along The Late Andesite Dikes With Movement Both Preceding And Following The Intrusion. All The Faults Are Precambrian. Two Sets Of Joints That Strike Ne And Nw Are The Most Common. Dips Are 82 Deg Nw And 87 Deg Ne Respectively. |
| Tectonic: | St. Francois Mountains |
| Alteration processes: | Rocks On The Upper Portion Of Big Mountain Exhibit Everywhere The Effects Of Extreme Alteration. Wall Rocks Are Altered To Chlorite, Epidote And Sericite. |
| MRDS | W016789 |
| DEP | 10072189 |
| Reference | {Analytical Data:: SRC.REF: LAKE, M.C., 1933 , 16 TH INT. GEOL. CONG. GUIDEBOOK 2 , P. 64.}{Deposit:: CRANE, G.W., 1912 , THE IRON ORES OF MISSOURI: MO. BUREAU OF MINES AND GEOL., 2D SER., V. 10 , P. 108 - 120 .}{Deposit:: MURPHY, JOHN E., AND OHLE, ERNEST L., 1968 , THE IRON MOUNTAIN MINE, IRON MOUNTAIN, MISSOURI, IN: RIDGE, J.D., ORE DEPOSITS OF THE UNITED STATES, 1933 - 1967 (GRATON-SALES VOLUME): NEW YORK, AM. INST. MINING, METALL. PETROLEUM ENGINEERS, V. 1 , P. 288 - 302.}{Deposit:: LAKE, M.C. 1933 , THE IRON-ORE DEPOSITS OF IRON MOUNTAIN, MISSOURI, IN: 16TH INT. GEOL. CONG. GUIDEBOOK 2 , P. 56 - 67}{Deposit:: WINSLOW, ARTHUR, HAWORTH, E., NASON, F., 1894 , A REPORT ON THE IRON MOUNTAIN SHEET INCLUDING PORTIONS OF IRON, ST. FRANCOIS AND MADISON COUNTIES: MO. GEOL. SURV., 1 SERV., V. 9 , SHEET REPORT NO. 3 , P. 56 - 61.}{Deposit:: 1910 DIREXPL 3 HOLES INDICATE A CONSIDERABLE THICKNESS OF CONGLOMERATE ORE. 50 FT AND 8 IN OF SOLID VEIN ORE ISENCOUNTERED IN ONE HOLE.}{Deposit:: DIREXPL OLD IRON MOUNTAIN COMPANY DRILLED 3 HOLES IN THE FOOT WALL OF THE BIG PIT AT LITTLE MOUNTAIN AND CUT CONSIDERABLE ORE.}{Production:: CRANE, G.W., 1912 , THE IRON ORES OF MISSOURI: MO. BUREAU OF MINES AND GEOL., 20 SER., V. 10 , P. 108.} |
| Reporter | Weeks, Robert |