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Cu-Au-Mo porphyry-type and Cu skarn-type mineralization in the Bingham mining district of Utah are temporally and spatially related to a suite of monzonite and quartz monzonite porphyry intrusions comprising the Bingham complex. Structural control on mineralization at the Bingham Canyon mine has been described at the scale of individual large-scale folds and fracture sets but no integrated pattern for the synmineralization deformation structures has emerged from earlier research. In the work reported here we have investigated hitherto largely unrecognized components of deformation (translations, rotations, and strains) associated with emplacement of many cubic kilometers of granitic rocks in the intrusions of the Bingham district. We have used both the local three-dimensional static mine model and the regional context in digital kinematic two- and three-dimensional forward and reverse modeling to identify a geometrically valid and admissible fault framework for the Bingham district and a kinematic solution for this framework through time. The results indicate that porphyry intrusions and associated mineralization were emplaced during reactivation of a basement-dictated linked system comprising two sets of northwest- and (north)-northeast-trending strike-slip faults. Both sets operated as transfer faults during extensional collapse of the Sevier orogen in the Eocene. Each fault set is characterized by overstep geometries with relay, ramps breached by faults (re)activated in extension. Strike-slip was accompanied by progressive dilation of the extensional faults in fault oversteps to permit emplacement of composite stocklike (low aspect ratio) intrusions. The kinematic fault framework identified provides a new structural context for porphyry- and skarn-type mineralization at the Bingham Canyon mine, with potential for linking mineralizing fluid flow to three-dimensional structure and the development of that structure through time. [ABSTRACT FROM AUTHOR]

Systematic exploration by Erdene Resource Development Corp. since 2005 in an underexplored region of southwestern Mongolia resulted in identification of three resources, including two epithermal gold deposits and one porphyry Mo-Cu deposit, plus several prospects and advanced projects that form the newly defined Khundii ('Valley') mineral district. The district is hosted by a Carboniferous island-arc terrane, part of the Central Asian Orogenic Belt. A regional exploration program was initiated by Erdene in 2009 over 110 000 km², based on the success at the Zuun Mod Mo-Cu porphyry deposit. Exploration included compilation of existing geological, geochemical and geophysical data and interpretation of satellite imagery, followed by ground exploration that included stream, soil and rock chip sampling, and geological and alteration mapping. Following the discovery of the Nomin Tal Cu-Au prospect in 2011 a 400 x 400 m soil survey over most of the exploration license identified Pb-, Zn- and Au-in-soil anomalies over a ~1.5 x ~5.5 km area. The first drill hole in the soil anomaly discovered the Altan Nar Au-polymetallic intermediate sulphidation deposit; veins of coarse crystalline quartz-adularia and carbonate gangue host the metal sulphides. The Bayan Khundii low-sulphidation gold deposit was discovered in 2015, ~16 km southeast of Altan Nar, including 7 m at 27.5 g/t Au from 14 m depth in an early drill hole. Discovery of the Khar Mori Au prospect was announced in early 2021, ~3.5 km north of Bayan Khundii, with one drill hole reporting 45 m of 5.97 g/t Au from 10 m depth. Later in 2021, drilling discovered wide zones of disseminated gold at Ulaan Southeast (up to 258 m at 0.98 g/t Au from 92 m depth), ~800 m west of Bayan Khundii. Epithermal quartz-adularia-Au veins with colloform bands and illite alteration at the Bayan Khundii deposit overprint earlier porphyry-related lithocap alteration. [ABSTRACT FROM AUTHOR]