Early Vaughn Mine, Barnesville, Lamar County, Georgia, USAi

Regional Level Types
Early Vaughn Mine	Mine
Barnesville	Town
Lamar County	County
Georgia	State
USA	Country

The Early Vaughn mine, which is 3.9 miles southeast of Barnesville, was one of the most important sources of sheet and punch mica in the district from March 1942 until mid-1944. The deposit was opened by Early Vaughn during World War I and was further prospected by J. E. Burleson in 1918. It then lay idle until 1938, when Gary Goggans dug a narrow trench to a maximum depth of 18 ft. A little work was done by Vaughn in 1939, and the property was leased to L. M. Johnson early in 1941. The main opening was lengthened and deepened until March 1942, when the deposit was sold to the Meyer and Brown Corp., of New York City. Johnson states that he produced 60 tons of mine-run mica during his operations. According to Ray Ward, manager for the Meyer and Brown Corp., 128 tons of mine-run mica was obtained during the most recent operations. The deposit was diamond-drilled by the U. S. Bureau of Mines in May 1945.

The tabular pegmatite body splits downward into two "roots" and was mined in a cut 85 ft long and 8 ft wide. This opening was extended downward and westward as an inclined underground stope, and by 1942 most of it was 60 to 70 ft deep. A narrow branch stope along the west-wall mica zone rakes north to a reported depth of 90 ft. This branch stope was then continued to the southeast around an abrupt right-angle bend in the hanging-wall contact, and on the 81-ft level a juncture was made with the east-wall workings to form an opening about 25 ft wide (September 1943). Except for a large quartz pillar the rock between the two stopes was then mined away to form a single stope that was bottomed in gneiss at a depth of 95 ft. From September 1943 to January 1944 operations were confined to the east-wall zone near the south end of the mine, where a heading was driven northward at a depth of 40 ft. Much exploratory work was done in an effort to find the downward continuation of the pegmatite. Waste rock from mining operations at higher levels was allowed to accumulate in the deepest stope, whose floor is now covered by 15 to 25 ft of this material. Diamond drilling by the U. S. Bureau of Mines, however, has confirmed the reports that the deposit was bottomed in this stope.

Near the surface the pegmatite body is tabular in form, but with depth it becomes complicated by branches, protuberances, and exceedingly abrupt variations in thickness. The range in thickness is from 3 to 24 ft, and where it is thickest the pegmatite contains a massive quartz core as much as 10 ft thick. This quartz lens thins toward the surface. Much of the early mining was done between the quartz and the hanging-wall contact; the richest part of the deposit evidently was at a depth of 50 to 70 ft, where the quartz is thickest. In cross section the south part of the pegmatite body is like an inverted Y. The stem of the Y is the trace of a steeply dipping tabular body that forks downward into two arms at a depth of 60 ft. The thin west arm pinches out in the bottom of the deep stope, and its keel plunges northward at a low angle as far as an abrupt bend in the west wall at the north end of the stope. The east arm is 2 to 10 ft thick, and its line of junction with the west arm pitches north at a low angle.

Two principal and one subordinate mica concentrations have been mined. The west-wall shoot, which was followed along the wall from the surface to the deepest part of the mine, was persistent and contained mica of the best quality. The east-wall shoot was worked chiefly in the deeper part of the mine. The subordinate mica shoot, which lay near the thickest part of the quartz mass and below the junction of the two arms of the deposit, is reported to have been a foot or two thick and about 8 ft in height and to have plunged north at an angle of 15°. In it the mica books were clustered near the west wall of the east arm of the pegmatite body. Where the two arms joined near the thick quartz mass this shoot arched over toward the west and joined the west-wall mica shoot.

The pegmatite body in the north half of the mine is relatively thin and tabular near the surface but thickens to 24 ft near the bottom of the stope. In the north wall of this stope, the body pinches abruptly to 8 ft and extends northward as a relatively fine grained aggregate of quartz, scattered small mica flakes, plagioclase, and perthite. Little coarse mica is present in this rock. Throughout the entire deposit, northward plunging structures are characteristic. These include the central quartz mass, the keels of both arms of the pegmatite body, the crest of the irregular gneiss septum that separates the two arms, and the richest mica shoots. In general the deposit strikes N. 30° E. and dips west-northwest. It cuts across the steeply dipping layers of the enclosing biotite gneiss at angles of 10° to 15°. The gneiss in the lower levels of the deposit is partly granitized, and its foliation is contorted. In the trench south of the open-cut the pegmatite is only 3 to 6 in. thick. The foliation along the west wall is parallel with the contacts, but along the east side it swings from a northwest strike to one nearly parallel with the walls, possibly owing to drag. Thus this part of the pegmatite may have been emplaced along a fault.

The pegmatite consists of quartz, plagioclase, muscovite, minor perthite, and a little black tourmaline, garnet, apatite, pyrite, and beryl. Some of the quartz and perthite occur in subgraphic intergrowths. Much of the plagioclase is dark green. Pyrite occurs chiefly along fractures in massive quartz. The mica is light pinkish buff, but a few books are greenish and have brownish borders. In general the quality is very good, and the material is flat, hard, and free splitting. Cracks are the chief defect, and a few books are locky. Others contain minute, widely scattered black specks. The mine-run mica has yielded about 6 percent trimmed punch and sheet, 26 percent untrimmed punch, 12 percent washer, and 56 percent scrap. In general the books are rather small, and the ratio of trimmed punch to trimmed sheet is 9:1. Nearly 88 percent of the trimmed sheets were in the l 1/2-by-2-in. and 2-by-3-in. size categories. The remainder included sheets as large as 4 by 6 in.

Both arms of the thicker part of the deposit have been mined out, and the simpler tabular sections of the body were found to contain insufficient mica for commercial operation. The deposit therefore appears to have been nearly exhausted. The workings are partly filled with water and debris, so that reopening of the mine for further prospecting and develop inert would involve considerable expense.