| Basis for focus area |
Mid- to late-Miocene Kiewit mine disseminated gold mine and quartz-carbonate-adularia veins and stockwork in general Rodenhouse Wash area, which was originally discovered as a beryllium prospect. Gold Hill mining district boundary from Krahulec (2018b). |
| Identified resources |
Historical and current production of gold and tungsten. |
| Production |
Kiewit mine has had sporadic low-grade production since 2014. Currently active in 2021, estimated 3,800 oz Au and 3,500 oz Ag produced in 2020. |
| Status |
Past and current mining. |
| Estimated resources |
Pre production estimated resource of 50,000 to 120,000 oz Au with an average grade of 1 g/t (Robinson, 2016). |
| Geologic maps |
Robinson (1993), scale 1:24,000; Nolan (1935, plates 1 and 2), scale 1:62,500 and 1:24,000, respectively. |
| Geophysical data |
Inadequate Rank 4 aeromagnetic and Rank 5 aeroradiometric coverage. |
| Favorable rocks and structures |
Polymetallic pipes and skarn in Jurassic granodiorite; skarns, polymetallic veins, and replacement deposits in the Mississippian Ochre Mountain Limestone and Pennsylvanian Ely Limestone associated with Jurassic and Eocene intrusions; late Oligocene/early Miocene high silica rhyolite dikes evidence for concealed Climax type Mo porphyry; late Miocene low-sulfidation Au quartz-adularia veins with Be and disseminated gold in Jurassic granodiorite. |
| Deposits |
Kiewit mine Climax mine (MRDS dep_id: 10098083), Rodenhouse Wash beryllium deposit (MRDS dep_id: 60001004). |
| Evidence from mineral occurrences |
MRDS; UMOS (Utah Geological Survey, 2021). |
| Geochemical evidence |
See Robinson (2006, 2016); Nolan (1935); Burwell (2018). |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
See Krahulec (2018b). |
| Comments |
The Gold Hill district is complex from a structural, igneous, and mineralization perspective (Robinson, 2006; Burwell, 2018; Krahulec, 2018b). Several igneous events are recorded in Gold Hill’s geology including a Jurassic granodiorite stock, an Eocene quartz monzonite stock, an Oligocene rhyolite porphyry dike swarm, and Miocene bimodal volcanic rocks. Multiple mineralizing events occurred at the Gold Hill district (Robinson, 2006; Krahulec, 2018b), and at least three ages of mineralization are recorded (Jurassic, Eocene, and Miocene). Late Oligocene Climax-type porphyry Mo potential related to the high silica rhyolite dikes is hypothesized and had limited drill testing in the late 1970s though no mineralization was intersected. Deposit types found at Gold Hill include skarns, polymetallic intrusion-related deposits, polymetallic veins and replacement deposits, disseminated gold deposits, and low sulfidation Be-enriched quartz-adularia veins. The Miocene low sulfidation system has very few of the characteristic trace elements typically associated with these systems and is characterized instead by the marked correlation between Au and Be. Similar low sulfidation veins from Climax mine north of Rodenouse Wash have been dated at 8 Ma by adularia K-Ar (Whelan, 1970), but a fine grained monzonite dike was dated by zircon U-Pb at 17.14 Ma (Burwell, 2018) so the timing of the low sulfidation mineralization and relation (or not) to magmatic activity is unclear. The interpretation here is that the mineralization was related to magmatic activity. |
| Cover thickness and description |
Variable. |
| Authors |
Stephanie Mills, Andrew Rupke, David A. Ponce. |
| New data needs |
Newmont flew an aeromagnetic survey over the district that the Utah Geological Survey is trying to secure as a donation. |
| Geologic mapping and modeling needs |
Updated geologic mapping needed west and south of main deposit area-S. Mills and A. Rupke of Utah Geological Survey are mapping the Clifton Quad across the southern portion at 1:24,000 scale. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and radiometric surveys. |
| Digital elevation data needs |
Lidar inadequate. |
