Northeastern Section (45th Annual) and Southeastern Section (59th Annual) Joint Meeting (13-16 March 2010)

Paper No. 3
Presentation Time: 2:15 PM


AYLOR Jr, Joseph G., Virginia Uranium, Inc, 231 Woodlawn Heights, Chatham, VA 24531 and BODNAR, Robert J., Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall, Blacksburg, VA 24061,

The Coles Hill uranium deposit (CHUD) is located to the west of the Chatham fault in the western Piedmont of the Smith River allochthon (SRA) in southside Virginia. In 1978 Marline Uranium, Inc. discovered and defined the ore bodies. Two defined ore bodies have two large surface radiometric signatures. Recently, the increase in uranium price has led to a renewed interest in this deposit.

The SRA is composed mainly of mylonitic gneiss and amphibolite overlying schist. The CHUD uranium resource as determined in a 2009 Canadian NI-43-101 compliant report is 119 million pounds of U3O8 weight percent at a cutoff of 0.025 weight percent U3O8 and an average grade of 0.06 weight percent. The ore is generally confined to healed hydrothermal fracture zones showing hematite, chlorite, apatite and titaniferous alteration in sodium metasomatised and silica-depleted rock. Sodium metasomatism is marked by rapakivi textures and riebeckite. Hematite represents an oxidation-reduction front associated with deposition of uraninite and pitchblende. The ore has been found to be generally in equilibrium with its daughter products.

The CHUD is composed of apparently two structurally different ore bodies, both northern and southern. It is hosted in the 440 my Leatherwood Granite associated with amphibolite interlayers and is capped by a brecciated zone. Uranium deposition post-dates the granite. The lowest boundary unit and western boundary of both ore bodies is a biotite gneiss or lit-par-lit mylonitic gneiss above the gradational schist of the Fork Mountain Formation. The ore bodies are bounded on their east by the Chatham fault, which is the western boundary fault of the Danville Triassic basin. The southern ore body is isoclinally folded with an axial planar foliation strike of N30E and dip of 35 SE to the drilled depth of 1500 ft. The ore plunges to the south at approximately 45 degrees. Going toward the north, the ore zone then gradually becomes more horizontal in the northern ore body where the foliation dip decreases. The northern ore body eventually plunges toward the north at approximately 15 degrees. Further extents of the ore to depth and laterally are still being considered.