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St George Mining finds visible copper, zinc sulphides in drill core

Published: 00:30 06 Jul 2015 BST

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St George Mining (ASX:SGQ) has identified visible copper sulphide and zinc sulphide mineralisation in the drill core at the Desert Dragon Central prospect at its wholly-owned East Laverton Property in Western Australia.

These were found within an additional thick ultramafic unit intersected after the DDRDD0005 hole was deepened to test for an extension of the lower ultramafic unit.

In addition, the location of the copper dominant DDRDD0003 - the second hole at the prospect - within the margin of a large, strong gravity anomaly validates the gravity feature as a priority volcanogenic massive sulphide (VMS) drill target.  

A sulphide-rich sequence from 293 metres to 300 metres returned spot values on the XRF analysis of 2% copper and 2.9% zinc.

A more definitive analysis of the metal content of the sulphide zones intersected by DDRDD0005 will be provided from laboratory assays.

Drilling data from DDRDD005 and DDRDD003 suggests that the prospective ultramafic channel at Desert Dragon Central thickens to the east of where DDRDD0003 was completed.

This suggests that targets to the east of the recently completed holes will be more prospective for massive nickel sulphides.  

The drill rig has now moved to the Aphrodite nickel sulphide prospect and drilling has commenced at one of the company’s best electromagnetic (EM) conductors – Aphrodite 4.

This is a very strong EM conductor which is situated on the southern portion of the Stella Range ultramafic belt.

John Prineas, executive chairman, said:

“Aphrodite 4 has classic features of a massive nickel sulphide deposit. It is a compelling target and we are excited to be testing it this week.
   
“The early results at Desert Dragon Central are excellent. The VMS potential of the area is now looking very real, and we have a vector to the east in our search for massive nickel sulphides. That happens to be where we have the Dragon 9 conductor, so the anticipation of drilling that target has risen even higher.”


Desert Dragon Central

Drill hole DDRDD0005 was initially drilled to 260 metres, intersecting a massive nickel sulphide stringer vein in the upper ultramafic unit.

It was subsequently deepened to a depth of 429 metres to test for an extension of the lower ultramafic unit at Desert Dragon Central.  

This encountered a further thick ultramafic unit with extensive sulphide accumulations including visible chalcopyrite (copper sulphide) and sphalerite (zinc sulphide).

Ultramafic sequences intersected in DDRDD0005 were interspersed with strongly sulphidic and metal rich sediments.

The base metal sulphides encountered in DDRDD0005 were zinc (sphalerite) dominant with interim XRF analysis indicating a peak zinc value of 4.35% zinc

St George’s second hole DDRDD0003 was drilled to test EM Conductor Dragon 8, which intersects the western margin of a positive gravity feature.

The gravity anomaly is interpreted to reflect dense sulphide-rich rocks. The hole also encountered thick ultramafic sequences with metal-rich sulphidic sediments.

Most notable in DDRDD0003 was a zone of copper sulphide mineralisation (chalcopyrite) focused between 123 metres to 130 metres.

Closed spaced XRF spot values averaged approximately 1% copper for this interval, with a peak spot value of 2.94% copper.

The associated zinc values for this interval are comparatively low. 

The typical zonation pattern in a VMS system has more copper dominant mineralogy closer to the centre of the VMS system, making this gravity feature a priority VMS drill target.  

Technical analysis of drilling data is continuing with the aim of mapping the alteration, mineral and geochemical domains of this VMS system. 

Its VMS potential was previously highlighted through the results of the 2012 reconnaissance drilling completed by BHP Billiton Nickel West as part of the previous Project Dragon farm-in arrangement.

With the prospective ultramafic channel at Desert Dragon Central thickening to the east of where DDRDD0003 was completed, targets east of the recently completed holes are expected to be more prospective for massive nickel sulphides.  

This adds importance to the drill holes planned to test underneath the thick interval of disseminated nickel sulphides at DRAC35 and to test the Dragon 9 EM conductor.


Aphrodite 4

Aphrodite 4 is a very strong EM conductor which is situated on the southern portion of the Stella Range ultramafic belt. It is a very “late-time” EM conductor with a time constant of 176ms and conductance of 2947 Siemens.

Newexco has modelled the conductor as EM plate APH_05.

Importantly, the EM plate is located in an optimal structural setting for the formation of nickel sulphide mineralisation.

The conductor is situated within a pronounced embayment on the eastern contact of the ultramafic body at Aphrodite.

This curved indentation of the ultramafic reflects the intersection of the ultramafic belt with a fundamental ENE-WSW transform fault.

This is a site where large volumes and high flow rates of very hot komatiite magma can assimilate the sulphur in the sulphide-rich footwall sediments identified at Aphrodite.

Drill hole APHDD0001 will be drilled to a depth of 300 metres at a dip of 60 degrees and an azimuth of 250 degrees.


Analysis

Early results from drilling at Desert Dragon Central have demonstrated the VMS potential of the area.

That visible copper, zinc sulphides have been intersected is also encouraging.

Excitement is also building as St George drills Aphrodite 4, the company’s best electromagnetic conductor with the classic features of a massive nickel sulphide deposit.   

Assays will be reported in the coming weeks with potential for significant intersections of mineralisation to be prioritised for faster processing.



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