Summary:
Coyote
Coyote is hosted within the Tanami Orogen which comprises a sequence of folded metasediments, mafic volcanics and intrusive rocks unconformably overlying Archaean basement. The known Archaean basement includes the informally named ‘Billabong Complex’ and the Browns Range Dome. The Tanami Orogen is a significant gold host with other major deposits located across the region including Callie 14Moz, The Granites 1.1Moz, and Groundrush 1.7Moz.
Locally, Coyote is hosted within the Killi Killi Formation. These are sand rich Proterozoic turbidites comprised of poorly sorted sandstones, siltstones and variable amounts of carbonaceous mudstones. The Killi Killi sequence extends well over 100m in thickness, however the individual beds range from 0.3m to 15m thick. Within the Coyote Central deposit, the ‘Marker Siltstone’ and ‘Kavanagh Sandstone’ are important marker units for mineralisation interpretation and boundaries.
Coyote is obscured by a widespread paleochannel and is deeply weathered. The oxide profile comprises weakly consolidated sand, sheetwash and alluvial lithologies and clay-dominated sequences. This is overlain by transported red aeolian sand. The deeply weathered profile sits directly over the top of the in-situ bedrock with limited saprock present. Oxidised saprolite is commonly present to depths of >100m.
Structurally, the Killi Killi Formation has been tightly folded into an angular anticline. The Coyote Central deposit is located trending east-west on a small parasitic fold within the greater anticline, plunging shallowly west at ~15°. The anticline’s northern limb dips from 30-50°, and the southern by 70-90°. The southern limb has a secondary fold axis known as the Buggsy anticline, a drag fold associated with the Coyote Fault that offsets the stratigraphy. These limbs contain smaller faults and parasitic folds controlling mineralisation at mine scale. The Marker Siltstone and Kavanagh Sandstone have been the primary units used to delineate the sequence and orientation of the bedding and fold structures.
Mineralisation is hosted in narrow high-grade quartz veins that are concentrated around the fold hinge areas. The mineralisation presents in the form of quartz veins parallel to bedding and are often concentrated in areas of local folding. In areas such as the high-grade Kavanagh lode, these veins can extend completely through the fold hinge zone (Axial Core Zone) and often host coarse, visible gold.
Mineralisation at Coyote is made up of a number of discrete zones hosted within the hinges and proximal limbs of the Coyote Anticline. Lodes are repeated through the stratigraphic sequence.
Single zones range in strike length from 100-600m, height of 50-200m and widths from 0.5-20m in width.
Overall, the extents of the Resource are;1,200m strike by 200m width, by 460m depth.
The Resource is considered open both along strike, down dip, and deeper into the stratigraphic sequence.
Sandpiper
Locally, Sandpiper is one of the deposits hosted within the Proterozoic Bald Hill sequence. The sequence is comprised of basalt, dolerite, graded sandstones and thinly-bedded siltstone and mudstone units and ranges from 100-300m in thickness. The dolerite and basalt units make up the majority (~70%) of the sequence. The mafic units have been metamorphosed to greenschist and amphibolite facies.
Sandpiper occurs on an elevated zone with remnant outcrops of quartz visible at surface. The area is covered by up to 2m of transported sandy red soil underlain with colluvial gravels soils and ferricrete. Mottled kaolinitic clays form a 10-25m thick weathered layer above the oxidised upper saprolitic zone. The saprolite is heavily weathered with only minor mafic crystalline textures or sedimentary bedding structures remaining visible. The saprolite zone extends from 20-40m deep and up to 60m in heavily sheared zones where preferential weathering has occurred.
Structurally, Sandpiper occurs on the southern limb of an overturned recumbent anticline which plunges 60° to the east. The northern limb is not known to host any significant mineralisation. A late-stage southern dipping fault offsets the sequence and mineralisation on a small sub-1m scale. The upper part of the sequence overturns to form a fold hinge at the eastern end of the deposit. At the southern extent of the deposit, the stratigraphy changes orientation to a more southerly orientation. This change in orientation is associated with a breakup of main lodes into a series of discontinuous stacked lodes.
Mineralisation is concentrated within sheared sediments or on the contacts of the fine-grained sedimentary beds and the mafic units. This mineralisation occurs as concentrated gold bearing sulphides around quartz carbonate vein salvages. Later stage vein sets forming a stockwork cross cutting the main mineralised veins also occur. Most of the gold is associated with sulphide content in the veins.
Mineralisation at Sandpiper is made up of a number of discrete zones hosted within the southern limb and hinge of the overturned anticline structure. Major lodes are repeated through the stratigraphic sequence with minor lodes being sporadically present parallel to the main mineralisation orientations.
Single zones range in strike length from 40-375, height of 50-310 m and widths from 0.5 – 9 m in width.
Overall, the extents of the Resource are 610 m strike by 35 m width, by 420 m depth.
The Resource is considered open both along strike and deeper into the stratigraphic sequence.