Castle Minerals Limited (ASX: CDT) has extended Main Lode shallow high-grade mineralisation further south at the company’s Wanganui project in the Meekatharra gold mining district of Western Australia through recently completed 3172m, 48-hole multi-target RC programme.
Drilling to test a magnetic low anomaly immediately south of the Main Lode South Pit returned 4m at 8.33g/t Au from 18m, including 2m at 15.39g/t Au from 18m and 2m at 1.27g/t Au from 25m.
Other holes drilled under the South Pit were designed to test for depth extensions to mineralisation previously intersected by Castle. An intercept of 4m at 1.32g/t Au from 71m was from one of several holes that also intersected at depth the strong shearing with sericite-pyrite alteration and quartz veins that is usually associated with the mineralised host structure.
Two holes to test for the interpreted down-plunge extensions of a high-grade shoot at the shallow Main Lode North Pit, successfully intersected the targeted zone of alteration, confirming the presence of the mineralised structure.
However, the relatively low-grade anomalism indicates that the plunge of the high-grade mineralised ore shoot within the host structure is also most likely steeper than interpreted.
Two reconnaissance holes were drilled on east-west sections approximately 100m apart, were designed to test a 300m north-south trending magnetic low coincident with the interpreted northern extension of the Main Lode, commencing approximately 100m north of the North Pit (North Target).
Results from this step-out drilling to locate the inferred mineralised structure included 2m at 1.02gt Au from 21m which, when combined with multiple zones of low-grade anomalism that were observed, provide encouragement as to the prospectivity of the Main Lode away from the area of historical mining.
Twenty-eight holes comprising more reconnaissance-style drilling were designed to test additional linear structures inferred from the recent aeromagnetic survey. Several holes successfully intersected zones of shearing and alteration that elsewhere on the project area are indicative of the presence of a mineralised structure. This will provide a solid basis for follow-up work aimed at vectoring in towards any high-grade mineralisation that may be present.
Managing Director, Stephen Stone said a recently flown high-resolution aeromagnetic survey confirmed that known gold mineralisation and shearing at Wanganui is associated with a series of north to north-east trending structurally-controlled linear magnetic lows, possibly representing magnetic destruction or other alteration features within the granodiorite host.
Historical mining and drilling data has shown that gold mineralisation is associated with at least four of these linear magnetic low zones. The recent geophysics highlighted extensions to the known Main and East Lode structures as well as identifying two additional parallel structures west of the main lode which were obscured by surface cover.
Castle will review these latest results and refine its structural interpretations to improve ore plunge predictions and the design of a follow-up programme that will also focus on the newly identified zones of encouraging alteration.
We are pleased to have confirmed that near-surface mineralisation at Main Lode South Pit continues to the south and to also encounter encouraging anomalism in reconnaissance holes to the north of the North Pit,” Mr Stone said.
“Zones of alteration usually associated with gold mineralisation in the project area were also intersected in holes drilled to investigate several new targets derived from the recent aeromagnetic survey.”