Nathalie Mining Company (Gumbo Mine), Pierson Creek mining district, Greene County, Missouri, USAi

Regional Level Types
Nathalie Mining Company (Gumbo Mine)	Mine
Pierson Creek mining district	Mining District
Greene County	County
Missouri	State
USA	Country

The mine of this company is located about a half mile above the Phelps mine, on the western bank of the creek; it was formerly known as the Gumbo mine, and is immediately contiguous to the Kodak mine. Both of these were equipped during 1893 with new steam hoisting plants and concentrating works. The following description is the result of an examination made by the writer in April, 1893: The shaft was then only 34 ft. deep, and the ore was encountered at 14 ft. below the surface; the workings were in a bed of soft, drab shale, gritty and highly calcareous, called "gumbo;” it seemed to lie in a horizontal position, but the bed varied in thickness from 1 to 12 ft or more; a hard, dense limestone occurred as a cap rock here, though, sometimes, massive blue shale immediately overlay the gray "gumbo." The ore was most abundant near the top of the latter, and consisted of crystals of galena and blende, both large and small; It was, however, also disseminated throughout the body of the shale in fine crystals, and occurred in larger crystals along crevices which traversed the roof rock; but it was never disseminated through this roof rock. These crevices, as exposed in this mine, are many of them mere joints, opened by solution, and run in all directions. No one prominent fissure or fault plane could be found here, though carefully looked for. The ore was also some times concentrated in the shale along the bottom rock, but is said to never penetrate the latter. Bosses, called "boulders," and ridges or bars of limestone were often found running through the mass of the shale in a very peculiar manner, very much as if the latter had been laid down upon an eroded surface; the absence of any appearance of oxidation or other weathering effects is, however, opposed to this interpretation. Another, and a perhaps more probable explanation, is that these limestone ridges and bosses are merely more highly calcareous portions of the formation; possibly developed through some secondary introduction of waters containing lime in solution.

In the hill-side and bluff, just east of the creek, beds of Lower Carboniferous limestone and chert are well exposed up to a height of 100 or 150 ft. above the creek; they are undisturbed, and lie in a horizontal position. Several shallow shafts and pits had been sunk on this hill-slope, up nearly to the very top of the hill, along the line of a crevice running northwest to southeast. This crevice was well exposed in one of these shafts on the hill, and the rocks are not faulted along it; it is filled with breccia of country rock, through which a small amount of galena is diffused. The workings of the mines just described were, in a general sense, in the continuation of this crevice, but, as already stated, no such vein-like opening was detected in the mines themselves. Some are inclined to attach great importance to the crevices, and describe them as accompanied by great shearing and faulting of the strata. We are unable to detect such here, and do not see that these crevices are in any respect different from joint crevices found throughout the state and else where, especlally in limestone rocks, often unaccompanied by any ore whatsoever. In the present case, they doubtless have some relation to the distribution of the ore, but to consider them as so called "true fissure veins,” extending to indefinite depths, is extravagant, to say the least. At Bseveral localities in this vicinity evidence of faulting was seen, but no great amount of displacement can be demonstrated.