Docketing of Information Written Public Comments Received from on the Private Fuel Storage Environmental Impact Statement

The southern part of Skull Valley has potential for shallowly buried mineral deposits. The most likely deposit type is either skarn/porphyry copper deposits, perhaps with surrounding polymetallic lead-zinc-silver replacement deposits or "distal disseminated" gold-silver deposits. The area (1) is structurally complex with both thrust and high-angle faults, (2) contains lithologic units favorable for mineralization, particularly limestone and dolomite, (3) is within the "Unita trend" of Eocene Oligocene intrusive rocks, and (4) is within the Park City-Bingham Canyon-Gold Hill belt of metallic mineral deposits. In addition, three distinct aeromagnetic anomalies are present in the area and may represent buried intrusive or volcanic rocks beneath alluvial fill. Gravity surveys suggest that bedrock is at relatively shallow depths beneath several of these anomalies. Minor lead zinc-silver, iron, copper-silver, and arsenic-antimony-silver mines and prospects are found in the adjacent Cedar and Stansbury Mountains, but most are too far away to be related to the magnetic anomalies. The southern Skull Valley area has sufficient geologic merit to justify additional work to improve and refine exploration target areas. Suggested work includes detailed ground magnetic surveys; additional geophysical surveys to identify alteration, sulfide mineralizations, and other characteristics; and field mapping and sampling of outcrops close to the identified target areas to identify subtle alteration or distal mineralization. PURPOSE AND SCOPE In mid-November 1998, the Governor's Office of Planning and Budget asked the Utah Geological Survey to evaluate the mineral potential of Skull Valley and the adjacent foothills of the Stansbury and Cedar Mountains. There was a question whether a proposed railroad spur might impact development of known or potential mineral resources. The study consisted of reviewing the available published information on the geology, geophysics,