Mt Thirsty Cobalt-Nickel-Manganese Oxide Project

Conico Ltd through its wholly owned subsidiary Meteore Metals Limited owns 50% of the Mt Thirsty Project in joint venture with Barra Resources Limited. Mt Thirsty is situated approximately 20km north west of Norseman in Western Australia, close to main road, rail and pipeline infrastructure.

 

For more detail please refer to the Mt Thirsty Project website www.mtthirstycobalt.com

 

The Mt Thirsty Co-Ni-Mn oxide deposit which is developed over Archaean ultramafic rocks differs from typical nickel laterite occurrences in that it contains relatively high cobalt values. The particular mineralogy of the deposit, which is a product of a unique weathering history, allows for rapid high leaching recoveries (approx. 95% Co and 80% Ni), at moderate temperatures and normal atmospheric pressure utilising weak, acidic reagents. Compared to some other oxide deposits processing is simpler as no expensive and potentially troublesome autoclaves are required.

 

Mt Thirsty has a current JORC (2004)* Indicated Resource of 16.6 million tonnes at 0.14% Cobalt, 0.60% Nickel and 0.98% Manganese and a JORC (2004) Inferred Resource of 15.3 million tonnes at 0.11% Cobalt, 0.51% Nickel and 0.73% Manganese over a length of 1.8 kilometres and a width of up to 850 metres. The orebody is relatively flat lying with an average thickness of 12m and an average depth below surface to the top of the orebody of 14m. The total Indicated and Inferred Resource contains approximately 177,000 tonnes of nickel, 40,000 tonnes of cobalt and 274,000 tonnes of manganese.

 

Metallurgical testing and pre-feasibility work has highlighted the potential world class nature of the Mt Thirsty Project. Mt Thirsty has the potential to emerge as a significant cobalt supplier.

 

A base line flowsheet has been developed for Mt Thirsty ore using sulphuric acid leaching. A relatively high cost, high recovery processing plant designed on this flowsheet would produce a mixed sulphide precipitate (MSP) containing cobalt and nickel and a separate manganese carbonate product.

 

Recently several phases of metallurgical test work by consultants RMDSTEM on a bulk sample from the Mt Thirsty oxide deposit were completed with some promising results.

 

Test work demonstrated that approx. 80% of the Co and >20% of the Ni should be able to be extracted in 4 to 5 hours from Mt Thirsty oxide ores using low temperature (40oC) agitated leaching in closed tanks with very low acid consumption and low iron release. The low acid consumptions achieved of 25-50kg/tonne of ore compare with previous high Ni recovery test work undertaken by the joint venture partners of 450-500 kg per tonne. This represents a major breakthrough for the Mt Thirsty Oxide project as acid consumption is a major operating cost item.

 

Based on the most recent test work results RMDSTEM have proposed two simple conceptual flowsheets representing a completely different, low cost chemical system for processing cobalt - nickel oxide ores compared to previous flowsheets that were capital intensive and aimed at maximising both nickel and cobalt recoveries.

 

The recent test work has provided much encouragement in particular a significant reduction in both operating and capital costs compared to previous studies. Cost benefits of the new processes could potentially far outweigh the considerably lower Ni recoveries achieved.

 

 To view the Mt Thirsty Project Location Plan CLICK HERE

 To view the Mt Thirsty Project Cross Section 6,447,400N CLICK HERE

 To view a plan of the Mt Thirsty Resource Outline CLICK HERE

 

* This resource information was prepared and first disclosed under the JORC Code 2004. It has not been updated since to comply with the JORC Code 2012 on the basis that the information has not materially changed since it was last reported, refer ASX Announcement 8th March 2011: "Resource Upgrade", available to view via the Announcements page of this website.

 

Nickel Sulphide Exploration

 

A very thick sequence of originally olivine-rich, cumulate - textured ultramafic rocks has been intersected in holes drilled at Mt Thirsty. These rocks contain variable amounts of disseminated, vein and stringer-style sulphide mineralisation. The primary exploration target at Mt Thirsty is nickel sulphides associated with basal lava channel embayments located on ultramafic-basalt (footwall) contacts similar to those in the Kambalda region. A possible basal embayment type structure has been identified within the project area and is currently being evaluated.

 

In May 2010 RC hole MTRC015 intersected a thick zone of nickel sulphides assaying 3.4% nickel over 6m from a down hole depth of 201 metres, adjacent to the footwall ultramafic contact within an interpreted lava channel embayment, 400m west of the oxide deposit within E63/373 (refer Project Location Plan above). Follow up RC drilling yielded further nickel intersections of 2m at 5.9% Ni, 2m at 3.5% Ni and 1m at 4.0% Ni in holes MTRC020, 22 & 030 (refer Longitudinal Section below). A deeper diamond hole to test the down plunge extension of the nickel sulphide mineralisation intersected a thick pegmatite intrusion from 276m to the bottom of the hole. This pegmatite is interpreted as being relatively flat lying suggesting that a significant down plunge portion of any nickel sulphide mineralisation would have been stoped out by the pegmatite intrusion over a vertical thickness in excess of 220m from ~200m below surface.

 

There is a further 4km of untested footwall contact in E63/1267, a Mt Thirsty Joint Venture tenement 2km to the north of E63/373 (refer TMI Airborne Magnetic Image below showing footwall contact). Considering that nickel sulphides have been discovered in the vicinity of this contact in E63/373 the continuation of this contact into E63/1267 is a high priority target for nickel sulphides at shallow depth. A moving loop EM survey was completed over this area in 2013 and a number of conductors were identified which warrant drill testing (refer ASX Announcement, 11 November 2013: "Mt Thirsty EM Survey Results" available to view via the Announcements page of this website).

 

 To view the Longitudinal Section CLICK HERE

 To view TMI Airborne Magnetic Image CLICK HERE