This trip crosses a wide-expanse of typical Valley and Ridge geology and topography before reaching the gentler structure of the Powell River anticline with its numerous zinc and lead occurrences. The largest of these, the New Prospect mine, is Stop 3. Here the mineralization occurs in Maynardville Limestone along fault and shear zones rather than in collapse breccias. Stop 4 will be at the famous Thorn Hill section where the roadcut for highway US-25E traverses strata from lower Cambrian to lower Mississippian in age. Selected sites will be examined.
The remainder of this trip will cover the area northeast and southeast of the Mascot-Jefferson City district, concentrating on the post-Knox unconformity and its solution features. Stop 5, just south of Dandridge along Douglas Lake, provides a look at a quartz sand-filled depression in the erosion surface. At Stop 6, west of Dandridge at the Shady Grove area, two large, relic sinks filled with blocks of dolomite and chert will be seen. This karst development is believed related to the development of the large breccia bodies which are common to the upper Knox dolomite and which are ore hosts in the mineralized districts.
Figures & Tables
Zinc Deposits in East Tennessee
The mining of zinc in Tennessee dates back to 1854 although the presence of zinc minerals had been reported as early as 1844 by Gerard Troost, the first State Geologist. When the Mossy Creek open pit mine, in what is now Jefferson City, Jefferson County, was opened, it became the first mine in what is now known as the Mascot-Jefferson City Zinc District. In these early years, only the oxidized ore was removed, and mining stopped when the sulfide ore zone was reached because a method to treat “hard ore”, as it was called, had not yet been developed.
Mining continued at the Mossy Creek operation until 1858, then ceased through the Civil War years until 1867, at which time the property was taken over by the East Tennessee Zinc Company. This company built a smelter to manufacture zinc oxide, but after only a few months of operation, the company became involved in litigation and mining ceased.
In 1882, the Mossy Creek property was sold to the Eades, Mixter and Heald Zinc Company which operated intermittently until 1894, becoming the first substantial zinc mining company in Tennessee as well as the first to produce significant amounts of sulfide ore. This latter was made possible by the construction of a zinc smelter at Clinton, Tennessee, some 45 rail-miles to the west. The Mossy Creek mine was operated or prospected only sporadically thereafter, and was closed by its final owner, the American Zinc Company, in 1919.
In the meantime, the discovery of lead and zinc ore in the Powell River area of Claiborne and Union Counties, some 30 miles northwest of Jefferson City, caught the attention of the mine operators. In 1883, the New Prospect mine was opened with only the lead recovered. By 1889, Eades, Mixter and Heald had taken over, erected a mill and mined the property intermittently until 1897. The lead was handpicked and shipped to New Jersey while the zinc was barged to the smelter at Clinton. There was little further activity until World War II when the very high grade pillars were robbed.
The only other producing mine in the Powell River district was at Straight Creek. It operated from 1880 to 1894, the latter part of this period by Eades, Mixter and Heald Zinc Company, which also built a mill. Beyond this there was only a short period of exploration and mining from 1906 to 1908 and another effort by Universal Exploration Company in the latter part of World War II.