Parole Mine (Jumbo Shaft), Palmer Mines (Fourche-a-Cortois), Washington County, Missouri, USAi

Regional Level Types
Parole Mine (Jumbo Shaft)	Mine
Palmer Mines (Fourche-a-Cortois)	Group of Mines
Washington County	County
Missouri	State
USA	Country

This mine, operated by the Palmer Lead company, is situated in the SE. 1/4 of section 6, township 36 N., 1E, near the center of the southern line. The shafts are located on the hill-tops, about 200 ft. above the adjacent valley, and 800 ft. above Palmer postoffice. They vary in depth from 180 to 145 ft. The rock passed through is principally magnesian limestone.

The Jumbo shaft, examined by the writer, was 146 ft. deep. Only one run of ore was found, this at the bottom of the shaft, in a flat sheet generally about one foot thick, but varying from a few inches to 6 ft. This run is made up of a net-work of channels. Main channels and cross-channels are recognized. The former run generally NE - SW., and average about 4 ft. in width, though they range from 2 to 12 ft.; the latter average about 2 ft in width, and run in various directions. The contents of these channels consist generally of galena near the top and bottom, with a filling of barite between. Near the outcrop, the barite is not so abundant, and pyrite and limonite are found in its place. The barite is clearly seen to be deposited after the galena crystals were formed; it occurs both in nodular, dense forms, and friable, in which conditions respectively it is known as “ball tiff" and "chalk tiff." Well formed crystals of galena are often found lining small cavities, and crystals of anglesite are sometimes found in these. The country rock is a siliceous-looking magnesian limestone, containing many small drusy cavities, lined with dolomitic crystals. Larger cavities are also found, and the rock is thus very open and vesicular in places. These cavities are sometimes filled with clay, sometimes with barite, and are sometimes lined with drusy quartz, known as "mineral blossom" and as “moory flint.” Such quartz is very abundant in the residuary clays along the foot-hills, but is not so common on the hill-tops. Patches and lenses of chert are frequently found in the limestone here. Under the main run of ore is generally a series of layers of friable randstone, and of white and yellow clay; the limestone is usually soft and crumbly, both above and below the bed of ore.

A number of other shafts were sank in this immediate neighborhood, all operating the same sheet of ore. Other sheets and runs are found at different levels in other shafts. An upper one, at a depth of about 100 ft., consists mainly of barite, with a little galena and considerable pyrite; it is rarely worked. The second, which is of less importance than the first, is generally about 4 ft. above the lowermost and sometimes runs into it. The third, or bottom, which we have described, is the one principally worked.

In former years, much ore was obtained from the clay diggings, and both galena and cerussite were found. In this clay the galena frequently lay in sheets, which were, however, not horizontal, but lay in "pitches and flats," somewhat as we might expect the contents of such channels as we have described to lie, if the enclosing magnesian limestone were gradually removed by solution.