Abstract The Coles Hill uranium property is located in Pittsylvania County, Virginia, within the Smith River allochthon in Southside Virginia's Western Piedmont Province. The Coles Hill property is bounded on the east by the listric normal Chatham fault at the Triassic Danville basin. Uranium mineralization occurs in the footwall of the Chatham fault and is hosted in healed fractures and in hydrothermal apatite in the Leatherwood granite mylonite that is intruded by the Rich Acres gabbro amphibolite. The granite is silica depleted. The mylonite is foliated with a strike of 030° and dips 30°SE; the Chatham fault strikes 030° and dips 60°SE. The structural trap for uranium mineralization is contained on the east by the Chatham fault and beneath by unmineralized Leatherwood biotite gneiss, which is underlain by the Fork Mountain schist. Hematite staining of the ground surface is from weathering of Fork Mountain schist, which outcrops west of the Chatham fault at a constant distance of half a kilometer. In the southern property, pods of uranium mineralization plunge south at 45°. In the northern property, pods of uranium mineralization plunge northeast at 12°. Saussurite, rapakivi textures, Na- and K-metasomatism, titanite, zircon, apatite, calcite, and hematite are present. One possible uranium source is remobilization from the Triassic basin by westward-flowing meteoric waters that intersected the Chatham fault at depth and migrated upward and laterally into the Leatherwood granite. Another uranium source model may be introduction of uranium mineralization by hydrothermal fluids associated with emplacement and cooling of the Leatherwood granite. These fluids would have migrated upward into a structural trap where uranium minerals were precipitated in hydrothermal fractures.

The Spring Mill Lake watershed is located in the Mitchell Plateau, a karst area that developed on Mississippian carbonates in southern Indiana. Spring Mill Lake is a reservoir built in the late 1930s and is located in Spring Mill State Park. Within the park, groundwater from subsurface conduits issues as natural springs and then flows in surface streams to the lake. From 1998 to 2002, surface and subsurface hydrology and water quality were investigated to determine the types and sources of potential contaminants entering the lake. Water samples collected during base flow and a February 2000 storm event were analyzed for selected cations, anions, trace elements, selected U.S. Environmental Protection Agency (EPA) primary and secondary drinking-water contaminants, nitrogen isotopes, suspended solids, Escherichia coli , and pesticides. All of the water samples met the EPA drinking-water standards for inorganic constituents, except those collected at five sites in August 1999 during a drought. Nitrate nitrogen (NO 3 -N) concentrations were highest during base-flow conditions and displayed a dilutional trend during peak-flow periods. The NO 3 -N concentrations in water samples collected during the 2001 spring fertilizer applications tended to increase from early to late spring. All of the δ 15 N values were low, which is indicative of either an inorganic source or soil organic matter. Storm discharge contained increased concentrations of total suspended solids; thus, storms are responsible for most of the sediment accumulation in the lake. E. coli levels in 24% of the samples analyzed contained a most probable number (MPN) greater than 235/100 mL, which is the maximum acceptable level set for recreational waters in Indiana. E. coli does appear to be a potential health risk, particularly at Rubble spring. The sources of E. coli found at this spring may include barnyard runoff from a horse barn or wastes from a wastewater treatment facility. The pesticides atrazine, metolachlor, acetochlor, and simazine were detected during the spring of 2001. Atrazine, metolachlor, ace-tochlor, and simazine are used to suppress weeds during corn and soybean production. Additional sources of atrazine and simazine may result from application to right-of-ways, orchards, and managed forest areas.