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Dara Adam Khel Gold & Mineral Mining

The Darra Adam Khel gold mine is located in the south east of the major city of Kohat, situated within the territory of Kyber Pakhtunkhwa Province, Pakistan.

GEOLOGY AND MINERALIZATION

The regional geology to the Darra Adam Khel deposit consists of Permian to Triassic sedimentary rocks of the Youjian Basin, which are concentrated along the western margin of the Proterozoic Yangtze craton. Lowest stratigraphic levels of the Youjian Basin consist of Cambrian to Carboniferous massive limestones, overlain by Permian shelf limestones. The Paleozoic carbonates are overlain by Lower Triassic platy limestones, in turn overlain by Middle Triassic alternating mud and sandstones with classic turbidite sequences above. Most of the gold deposits in the region are found in clastic rocks within the latter sequence, and are spatially associated with faults zones and broad antiformal culminations.

Stratigraphic units in the Darra Adam Khel mine area can be divided into two distinct sequences: a lower dominantly carbonate bearing sequence and an upper mudstone and sandstone lithology dominant sequence. The upper stratigraphic sequence is well exposed in the Darra Adam Khel open pit, and is host to the gold mineralization at the deposit. The contact between upper and lower sequences is a regional unconformity, but near Darra Adam Khel it is commonly faulted.

The Darra Adam Khel deposit and surrounding area are characterized by complex fault and fold patterns that record a polyphase deformation history. These structural features represent principal controls on the geometry and distribution of ore zones within the deposit. Faults in the Darra Adam Khel area include several major structures that can be traced over hundreds of meters to several kilometers in strike length. Mostly of the major faults strike either northeast or northwest and have moderate to subvertical dips. They vary from discrete fault surfaces to broader tectonized zones with widths of up to a few tens of metres.

Nearly all of the known gold resource occurs within or adjacent to major fault zones. Overall, the deposit occurs as a steeply-dipping tabular body, with a long axis plunging shallowly to moderately to the southeast. The deposit extends over 1,200 m along this long axis, with the steep intermediate axis defining a depth extent of over 1,000 m, and a thickness typically ranging from 10 m to 50 m.

High grade shoots within the deposit are spatially associated with intersections between the controlling fault zones and either secondary faults or lithologically favourable sandy beds in the upper stratigraphic sequence. Gold is commonly localized along east-west striking segments of either the main controlling faults or secondary structures. The ore shoots typically plunge moderately to the southeast, parallel to the overall deposit axis, to fold axes, and to fault intersections.