Maxey Flats is an isolated plateau in northeastern Kentucky, near the city of Morehead. The radioactive waste burial site is located on the plateau, about 300 to 400 feet above the surrounding valleys.Radioactive waste burial at Maxey Flats began in 1963. Completed trenches at the site are about 20 feet deep, and occupy an area of about 0.03 square miles. As of January 1972, approximately 1.2 million curies of byproduct material, plus 460 pounds of special nuclear material, plus 87 thousand pounds of source material have been buried. Byproduct material is material made radioactive by exposure to radiation. Special nuclear material is plutonium, uranium-233, and enriched uranium-235. Source material is uranium and thorium, not including special nuclear material.Rocks in the Maxey Flats area are of Mississippian and Late Devonian age including, in descending order, the Nancy and Farmers Members of the Borden Formation, Sunbury, Bedford, and Ohio Shales, and upper part of the Crab Orchard Formation. The total thickness of these rocks is about 320 feet. All radioactive wastes are buried in shale of the Nancy Member.Mean annual precipitation at nearby Farmers, Ky., is about 46 inches. Infiltrating rainfall is temporarily stored in weathered bedrock on hilltops, and colluvium and soil on hillsides. The water later discharges in springs at the bases of the hills. Base flow in Rock Lick Creek and its tributaries is derived mainly from alluvium in the valleys, and the mantle of regolith, colluvium, and soil on adjacent sides and tops of hills. Little is known about the ground-water hydraulics of the area. If movement of dissolved and water-suspended radioactive materials from the burial site were to occur by natural processes, surface and ground water would be the means of transport.Well yields are low in all rocks at Maxey Flats, and most groundwater movement is in secondary openings, particularly joints. The ground-water system at Maxey Flats is probably unconfined, and recharge occurs by (a) infiltration of rainfall into the mantle, and (b) vertical, unsaturated flow from the regolith at the top of the hill to saturated zones in the Farmers Member and Ohio Shale. Discharge occurs by lateral flow from the mantle and bedrock to the sides of hills, or to alluvium in valley bottoms.