Starkey Mine, Madison County, Missouri, USAi

Regional Level Types
Starkey Mine	Mine
Madison County	County
Missouri	State
USA	Country

Description: A shallow pit has been dug in the bottom of the ravine in the removal of pyrites from the contact of a granular gray dolomite with the felsite porphyry which forms the hill known as Cottoner Mountain. A shaft sunk in the bottom of the pit was reported by Mr. Starkey to have cut 4 feet of dolomite, 4 feet of pyrites and then 5 feet of dolomite, containing fractures and cavities filled with pyrites, under which there was more pyrites. Another 5 x 5-foot timbered shaft has been sunk on the north side of the ravine about 12 feet above the pit and 60 feet N. 15° W. of it. This shaft was reported to have cut 9 feet of glauconitic dolomite, containing vugs lined with dolomite crystals; 14 inches of pyrites and 6 feet of sandy dolomite and sandstone. A third shaft was reported to have been sunk 525 feet S. 70° E. of the pit, but this was reported to be barren and was not seen by the writer. In September, 1937, Henry Crump and Son drilled two holes northwest and southwest of the pit. Each hole was 26 feet deep and was reported to have cut a little pyrites disseminated in the dolomites. The holes were reported as stopping in dolomite.

The pyrites occurs in lenticular masses or pockets in the dolomite adjacent to the porphyry. Both marcasite and pyrite are present. Most of the ore is brassy and massive, but some of it is granular and earthy. Two samples analyzed with the aid of X-rays contained chiefly pyrite. Where the sulphide was oxidized on the dump of the upper shaft, a white efflorescence was obtained which seems to be a new mineral, a ferrous sulphate tetrahydrate, which the writer has called starkeyite, after the mine.