Cloncurry Central

Introduction

The Cloncurry Central Project comprises nine exploration permits for minerals (EPMs), situated near Cloncurry in northwest Queensland.  All Tenements are referred to as “EPM” regardless of the application  / grant status.  The tenements cover approximately 950km2 of the Mount Isa Block (Figure 1).  Four of the tenements are part of the CJV between Xstrata Copper and Sovereign.

Exploration Potential

The tenements cover a large area of a highly mineralised province.  Although most of the area has been explored in the past, the potential remains for further economic discoveries, both in areas containing basement rocks at surface or beneath surfical cover and in areas of more substantial Mesozoic and Cainozoic cover.  By no means have all of the already generated geochemical and geophysical anomalies in the area been adequately tested and it can be anticipated that further detailed surveys will generate additional targets.

Numerous structural breaks are clearly visible on aeromagnetic images of the area (Figures 3 and 4).  Many of the significant mineralised deposits are associated with these faults or shear zones.  For example the Mary Kathleen uranium deposit to the west of Cloncurry, the Dugald River, Blackard, and Little Eva base metal deposits to the northwest of Cloncurry, the Eloise Cu-Au deposit to the south of Cloncurry, and the newly discovered Rocklands Cu-Co-Au deposit are all situated on structural breaks.  Continuations of these structures and other similar and parallel structures pass through many of Sovereign’s tenements.  These major structures and lower order splays require systematic exploration. 

Xstrata Copper has collected gravity data in the Cloncurry district as part of a regional programme.  Results are to be interpreted with follow-up of consequent targets.

Table 1: Cloncurry Central Project - Tenement Details

Figure 1: Cloncurry Central Project – Geological Map

Mount Avarice

The Mount Avarice EPM 8588, comprises three separate areas adjacent to the Cloncurry townsite.  The general Cloncurry area has long been subject to prospecting and historical mining, primarily for copper, and the tenement contains a number of abandoned workings and dormant mines.  More recent company exploration was originally focussed on the search for roll-front uranium in cover sequences, but later the search was primarily for iron oxide Cu-Au deposits. 

Exploration since the commencement of the CJV (2002) has focussed on the Turf Club Shear to the north and east of Cloncurry (Figure 2), where the following work has been undertaken:

• Detailed mapping, which outlined a series of north-striking dolerites interleaved with shales.  The package has been silicified to varying extents.
• IP/resistivity surveys, which located anomalies in the southern section of the survey area, just to the east of the Jasper Block.  These anomalies were named the Archer and Jasper Prospects. 
• The drilling of eleven RC holes, one RC/diamond hole, and one diamond hole to test the Archer and Jasper Prospects.  The holes intersected significant sub-economic Cu-Au mineralisation in both sedimentary and volcanic rocks.  Both haematite and magnetite alteration were present.  The best diamond hole intersection was 5.1m @ 2.25% Cu and 0.2g/t Au within a longer intersection of 98m @ 0.36% Cu.  The best RC intersections were 10m @ 1.47% Cu and 0.16g/t Au in the Archer Prospect and 10m @ 1.41% Cu and 0.59g/t Au in the Jasper Prospect. 
• Down-hole TEM surveys, which detected numerous small anomalies, considered to be indicative of stringer style mineralisation, but not of significant conductive bodies. 

A portion of the EPM containing the Archer and Jasper Prospects has been recently relinquished.  The strike extensions of the mineralised Turf Club Shear, both to the north and south of these prospects, are within the retained portions of the tenement.

Detailed geological mapping, rock chip and soil sampling, and IP surveys around three other areas of shearing and alteration have also been carried out.  The sampling did not return significant results, but the IP surveys produced a moderate level chargebility anomaly which requires follow-up work.  A ground magnetic survey was also performed.

Figure 2: Turf Club Shear Prospects

Mount Marathon

The Mt Marathon EPM 8586 is made up of two separate areas, situated to the northwest and northeast of Cloncurry.  The Turf Club Shear extends north-south through the eastern area.  Three prospects have been outlined along it.  From south to north they are the Shergar, Red Rum, and Fine Cotton.  Within the Mount Marathon tenement the shear hosts small-scale copper workings, including the historical Australian Margaret Mine.

Recent Exploration

Recent exploration has consisted of detailed geological mapping, an IP/resistivity survey over most of the length of the shear, and BLEG soil sampling over four areas.  The geophysical surveys outlined five target areas, but the soil sampling only pinpointed an area of existing workings.  Two of the prospects, Shergar and Fine Cotton, have been drill tested. 

At the Fine Cotton Prospect intensely altered dolerite, diorite, and calc-silicates, containing locally disseminated pyrite, were intersected.  At the Shergar Prospect dolerites containing up to 5% disseminated pyrite were intersected.  No significant Cu or Au values were obtained at either prospect and no further work is proposed over them.

Systematic rock-chip sampling has delineated a zone of moderate level multi-element anomalism requiring follow-up.

Fountain Range

The Fountain Range EPM 12561 is comprised of five separate areas.  It is situated within Cover Sequence 2 rocks about 40km west of Cloncurry.  Major northeast-trending structures pass through the area and numerous historical copper workings are present within it. 

Corella River

The Corella River EPM 12597 is comprised of seven separate areas, six of which are to the northwest of Cloncurry.  The southern extension of the Turf Club Shear passes through the other to the south of the town (Figure 2).  The four areas about 40km to the northeast of Cloncurry contain similar rocks, structure, and mineralisation to the Fountain Range EPM.

Middle Creek

The Middle Creek EPM 12807 is situated about 55km north-northwest of Cloncurry, within rocks of the Eastern Fold Belt, which are mostly covered by Mesozoic and Cainozoic sediments.  The basement rocks are comprised of metasediments, including calc-silcates, and volcanics of Cover Sequence 2, intruded by younger granite.  No significant mineralisation is known within the project area. 

Recent exploration at Middle Creek, has consisted of:

• The recognition of a 1km long magnetic anomaly adjacent to the regional scale northeast trending Quamby Fault Zone.
• An IP-resistivity survey over the anomaly, which outlined a 600m long, north-northeast trending anomalous zone.
• The testing of this zone with four diamond holes, which intersected strong magnetite alteration.  Some pyrite, pyrrhotite, calcite, and haematite alteration was also present.  The best intersection was 6m @ 0.35% Cu.

Undina South

The eight separate areas of the Undina South application, EPM 12458 is situated along the eastern margin of the Mount Isa Inlier to the southeast of Cloncurry.  It covers areas of the Soldiers Cap Group, which consists predominantly of metamorphosed turbiditic sediments and basaltic lavas.  Mesozoic cover is present in the eastern areas of the application.  The Soldiers Cap Group rocks contain Pb-Zn-Ag mineralisation at the Fairmile Mine about 10km along strike, to the south.  The Eloise Cu-Au mine, although close to the tenement, is situated on the Luveka Trend structure, which does not pass through the tenement.

Gypsy Creek

The Gipsy Creek EPM 15290 is situated to the northeast of Cloncurry, about 40km from the Ernest Henry Mine.  The tenement has a Mesozoic cover above the Proterozoic rocks of the Mount Isa Block. 

Nine Mile

The Nine Mile EPM 12408 is centred 20km northeast of Cloncurry.  It is situated near the eastern margin of outcrop of the Mount Isa Block and is comprised of three separate sections.  The two western sections are over rocks of the Mary Kathleen Group and the Nakaru Granite.  The eastern section has cover rocks over a probable mixture of granite and Soldiers Cap Group.  A number of northeast-trending structural breaks are interpreted to pass through the project area. 

Cotswold

The Cotswold EPM, 15320, is comprised of six separate sections.  It is about 40km north of Cloncurry and has a cover sequence of Cainozoic and Mesozoic rocks.  Aeromagnetic data indicate that a mixture of granitic and Eastern Fold Belt rocks, probably of the Mary Kathleen and Soldiers Cap groups are present beneath the cover.

Figure 3: Cloncurry Central Project – Carpentaria Joint Venture area - Aeromagnetic Image

© 2006 Sovereign Metals  |  Last Updated: 18/06/2007
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