York Peninsula Project
Phoenix Copper's Minlaton (EL4031) and Koolywurtie (EL4312) tenements are located on the eastern edge of the Gawler Craton within the 'Olympic Domain', a world class copper/gold province. The Olympic Domain extends from the Yorke Peninsula in the south, to Prominent Hill in the north, and hosts the Hillside (217 Mt at 0.7% Cu and 0.2g/t Au ), Moonta-Wallaroo (>355,000t of Cu and 2t of Au ), Carapateena, Prominent Hill, (200.3 Mt at 1.23% Cu, 0.5 g/t Au, 3.0 g/t Ag1) and the giant Olympic Dam, (9080 Mt at 0.87% Cu, 0.28 kg/tU3O8, 0.31 g/t Au, 1.5 g/t Ag1) deposits (See below).
Above: Phoenix Copper tenure relative to Olympic Domain IOCGU deposits.
The Minlaton and Koolywurtie tenements cover an area approximately 800km2 on the west coast of the Yorke Peninsula. The tenements are less than 30km from the neighbouring Hillside deposit and remain underexplored.
Phoenix Copper interpret that EL4031 and EL4312 contain similar structures, stratigraphy and geophysical signatures to both the Moonta and hillside areas.
Land Under Licenses
Phoenix Copper has applied for another substantial exploration licence (ELA2011/00278) over the Yorke Peninsula (see below). If granted, this would increase the total land Phoenix Copper has under exploration licences in this "new copper region" to more than 1,200 square kilometres. Rex Minerals Limited (Rex) has the largest tenement holding on the Yorke Peninsula.
The ELA has particular value, as it covers an area of what is interpreted to be the continuation of the Pine Point Fault, the host to Rex's Hillside Deposit. The Pine Point Fault is estimated to be close to the south-eastern boundary of the existing EL4031S held by Phoenix Copper. The inclusion of a new exploration licence following grant of ELA2011/00278 would provide greater certainty for any exploration planned over this prospective area of the (interpreted) Pine Point Fault.
Several magnetic anomalies within the area covered by this ELA are evident from magnetic data available from DMITRE. If ELA2011/00278 is granted, initial exploration work would entail the determination of the depth of cover over the more prospective areas and the potential of airborne VTEM surveys to assess the likely potential for structures and mineralisation associated with the magnetic anomalies.
As the ELA is contiguous with the southern portion of Phoenix Copper's existing EL4031, this will allow a greater degree of flexibility in planning the exploration programme for the southern portions of both EL4031 and EL4312.
Phoenix Copper Exploration Licences on the Yorke Peninsula and the recent Tenement Application ELA2011/00278 (hatched). Rex ELs are shown in yellow outline
VTEM Survey
A Versatile Time Domain Electromagnetic (VTEM) geophysical survey over the northern portions of Exploration Licences 4031 and 4312 between Balgowan and Port Victoria on the Yorke Peninsula was completed in December 2011.
Based on the quality of the preliminary VTEM data near the coast, an additional 30 line kilometres were flown much closer to the shoreline and at closer-spacing, (for highest resolution of data). The more closely-spaced survey covered the historic holes DD1 and DDH2 drilled by the South Australian Department of Mines in 1955, approximately two kilometres south of Balgowan. These holes intersected thin zones of copper mineralisation (DDH2: 0.33m @ 0.3% Cu 0.3% Ni from 105.5m) and therefore presented the highest priority for further investigation. It is known that this area also contains the suite of rocks that are more likely to host IOCG targets -- sheared Hiltaba suite granites and gabbros and metasomatite that contains up to 25% magnetite with traces of copper and nickel sulphides.
Since the Port Victoria -- Balgowan region remains largely unexplored due to regolith cover, this exploration program is necessarily heavily dependent upon geophysical input and Phoenix Copper is following a methodical approach for its Northern Yorke Peninsula tenements to provide the best selection of targets in the most cost-efficient manner.
Data from this recent VTEM survey has been processed and is very encouraging. Generation of conductivity "slices" at various depths has shown many areas of electromagnetic (EM) anomalism related to both very high and very low conductivity.
Images generated from the EM anomalies show indicators of potential sites for IOCG and other mineralisation styles, but require further assessment and refinement to identify high-potential targets.
Drill target generation incorporating occurrences of coincident anomalism in two or more datasets has also begun and several likely targets have already been identified.
The drill target generation will comprise an integrated assessment of all available structural and geological data, historical drilling results, geochemical sampling assays, radiometric, magnetic and gravity datasets.
This methodical process of interpretation of this data and comparison with other developed data - particularly the 3D magnetic data - is designed to increase the potential of a successful drilling programme and will continue into February and (possibly) March. During this assessment, a determination will also be made as to whether additional on-ground higher resolution EM and gravity surveying is warranted within the zones of multiple coincident anomalies, before finalising a ranking of what will be multiple drill targets.
Depth to Basement (Regolith Cover Depth)
To date the collation and interrogation of historical drilling conducted by BHP has shown that the depth of cover in the northern portions of EL's 4031 and 4312 is often less than 30m thick. This relatively thin cover provides a higher degree of confidence in the use of geochemical sampling to test geophysical targets for evidence of mineralisation and minimises the cost of drilling. This work has also provided information on the basement geology, and has provided a broad spread of geochemical assays of copper in soils over the area, both of which will be used to assist in drill target generation.
Nevertheless, exploration in this highly prospective area is "blind", as the regolith covers the geology and structures of the rocks. Geophysics is therefore the primary technology that allows exploration to "see through this cover", particularly where the cover sequence is thick.
The cover regolith also "blankets" the underlying rocks and interferes with the normal ion migration of minerals that so often provides soil geochemistry as another exploration tool for discovery.
The root systems of certain vegetation species can penetrate through the cover, (and often the calcrete immediately below the cover), and absorb minerals and water into the plant for sustaining nourishment. When plants exhibit unusually high levels of minerals absorption, this may indicate areas where minerals beneath the cover are more concentrated, providing similar exploration indicators as traditional soil sampling.
Once the appropriate vegetation species is identified, biogeochemical sampling may also be used as a guide to identifying anomalous mineral areas. Phoenix Copper has undertaken research and botanical sampling in an endeavour to determine if biogeochemical sampling is appropriate for exploration on the Yorke Peninsula. Samples have been collected and sent for trace element analysis.