Greasy Mine, St. Francois County, Missouri, USAi

Regional Level Types
Greasy Mine	Mine (Inactive)
St. Francois County	County
Missouri	State
USA	Country

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This mine is located in St. Francois county, about six miles south of Doe Run, in the N. E. 14, S. E. 14, Sec. 8, T. 34 N., R. 5. E. It is situated in a small ravine tributary to Wachita creek at the foot of the northeast slope of Bald Mountain.

The country rock in the vicinity of the mine consists chiefly of granite with some porphyry capping the higher hills like Bald Mountain. The Lamotte sandstone occurs in the valleys of the larger streams. The granite which forms all of the outcrops within a quarter of a mile of the mine is light pink in color and varies from holo-crystalline to porphyritic in texture. Its principal constituents are feldspar and quartz with some biotite and occasional crystals of apatite, zircon, and magnetite. At Bald Mountain it grades upward into a quartz porphyry. The Lamotte sandstone which lies unconformably upon the granite is usually light yellow to brown in color and rather coarse-grained, particularly at the contact with the granite where it becomes conglomeratic. The surface and soil, which are light colored and sandy, have resulted chiefly from the decomposition of the granite. None of the rocks show metamorphism other than weathering, the only secondary structure being numerous small fissures due probably to consolidation.

The ore outcrops at one point on the west bank of a small ravine. It occurs in the form of several small fissure v~ins in the granite which also carries some disseminated ore. The ore bearing veins are nearly vertical and have a strike of about north 25 degrees east.

Developments consist of a shaft 100 feet deep, from the 50-foot level of which drifts have been driven along the strike of the vein for a distance of 48 feet in a northeasterly direction and 70 feet in a southwesterly direction. The 48-foot drift encountered good vein ore throughout its length. The veins in this drift vary from a fraction to six inches in width and are often several in number, distributed over a zone two to five feet wide. At a point 30 feet from the shaft a cross drift has been driven 24 feet in a northwesterly direction. The first 18 feet of this drift is in granite carrying 10 to 15 per cent of disseminated ore. This ore is cut out abruptly by a two to three-foot seam of soft gray talcose material carrying disseminated ore and seams of hard massive hematite. Beyond this is hard pink granite, barren of ore except for thin seams of hematite cementing joints.

The 70-foot drift which extends southwest from the shaft is in vein and disseminated ore except for six to ten feet of barren granite near its south end through which it passed in good ore. From the middle of this drift a cross drift has been driven 20 feet to the southeast disclosing disseminated ore throughout its length.

The vein ore has been followed to a depth of 100 feet in the shaft and at that depth is enclosed by disseminated ore of the same grade and character as that showing in the cross drifts at the 50-foot level.

From the developments it would appear that there is here a zone of vein ore two to five feet in width and at least 100 feet deep and 130 feet in length which is bordered on either side by parallel zones of disseminated ore at least 20 feet wide.

The ore is a highly micaceous hematite, resembling graphite in appearance and is soft and greasy to the feel. Near the end of the northwest cross drift it is in part hard and massive and unfit for pigment purposes. The vein ore carries occasional stringers of milky quartz and is mixed with more or less talcose material. The disseminated ore carries numerous small individual crystals of pyrite and locally small quantities of chalcopyrite. Pyrite also occurs in the vein ore, particularly where the. latter is massive.

The best grade of ore is that in the small veins which run 50 to 80 per cent hematite. The disseminated ore ranges up to 20 per cent hematite, much of the ground assaying 15 per cent.

The deposit probably belongs to the pegmatitic class of vein filling and impregnation by replacement due to deep seated hot solutions.

The deposit is being exploited as a source of mineral paint and a mill is about to be constructed to separate the ore and rock. Experiments in milling have produced a product running 92.7 per cent hematite and it is thought that this can be improved upon. The milled product is used as a pigment under the trade mark "Formastat" and sells for from 90 to 130 dollars per ton. It is recommended as a coating for steel structures particularly those exposed to acid, damp, and corroding influences. By special processes it is given a gold, silver gray, or copper color, such treatment increases the cost of the product.

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

8 valid minerals.

Rock Types Recorded

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