Geology Siguiri is situated in the northern part of the Siguiri Basin of Guinea, and is underlain by Lower Proterozoic rocks of the Birimian metasedimentary and volcano-sedimentary formations. Where exposed, the sediments consist of a well-bedded turbiditic sequence of greenschist facies siltstones, sandstones, greywackes and minor conglomerates, with some brecciated and possibly volcanic members. However, stratigraphic relationships in the area are poorly understood due to poor exposure and a thick lateritic duricrust covering large portions of the lease. The Siguiri mineralisation occurs as secondary gold in alluvial or colluvial gravel in lateritic cover and primary vein-hosted mineralisation. The veins are quartz dominant and display various styles and orientations, with a sub-vertical northeast-trending conjugate quartz vein set predominating in most of the open pits, irrespective of the bedding orientation. Auriferous quartz veins show a robust lithological control and are best developed in the sandstone/greywacke units. The primary structural and lithological trend in the current mining area of Block 1 changes from a north-south orientation in the south to a northwest-southeast orientation in the north. The geology of Block 2 differs from Block 1 as it is mainly underlain by metavolcanic and volcanoclastics. However, mineralisation styles appear similar to those in Block 1, with Saraya appearing to be located on a north-south orientated structure. Deposit type Thr ........

Siguiri is currently a multi-pit fresh rock and oxide gold mining operation, mined by contract miner, Mota-Engil. The mining method is conventional selective mining using excavators and trucks on 3m high flitches. Three Caterpillar 6020B excavators are the main loading equipment matched with Caterpillar 777G dump trucks. In some deposits, a selective mining unit (SMU) of 10 x 10 x 3m has been defined based on historical grade control, the deposit type, and the mining equipment used to simulate the expected mining dilution and ore losses. Mining occurs primarily at Kami and Bidini pits in Block 1, as well as Saraya pit in Block 2.

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