Exploration Licence 5744 covers 661 square km located ~120 km north-east of Adelaide, on the eastern side of the Mount Lofty Ranges. It forms a part of SeeSaw Resources' Brownlow Project. Basement outcrop within the tenement is limited to...
Exploration Licence 5744 covers 661 square km located ~120 km north-east of Adelaide, on the eastern side of the Mount Lofty Ranges. It forms a part of SeeSaw Resources' Brownlow Project. Basement outcrop within the tenement is limited to Adelaidean metasedimentary rocks in the west. Geologically the area lies along the Nackara Arc, a tectonic belt that is host to many historical goldfields. The Nackara Arc was formed during the cessation of Delamerian Orogeny convergent plate tectonic deformation, and contains felsic, intermediate and mafic intrusions emplaced during a bimodal post-late kinematic magmatic event of Ordovician age. These igneous rocks are exposed in places, but largely are now buried under Tertiary and Quaternary Murray Basin sedimentary cover. The subject licence area is intruded by the Brownlow and Stonefield granites, which have been recognised locally in regional magnetic and gravity data. SeeSaw’s aim is to conduct greenfields exploration in the relatively underexplored Nackara Arc for possible skarn and porphyry type intrusion-related copper and gold mineralisation associated with felsic, intermediate, and mafic rocks that have intruded Adelaidean (Neo-Proterozoic) and Kanmantoo Group (Cambrian) metasediments. From doing a desktop review of historical exploration data including aeromagnetic data, SeeSaw concluded that the Brownlow and Stonefield granites have exploration potential for skarn and igneous intrusive-related copper and gold mineralisation. The Brownlow magnetic anomaly was interpreted to be related to skarn alteration associated with the Brownlow and Stonefield granites, an idea supported by the presence of reactive rocks (limestones and carbonaceous rocks) having a structural architecture that would facilitate fluid movement. On-ground exploration throughout the year across the tenement involved structural mapping to identify potential settings for economic mineralisation. A number of areas with recognised mineralisation were also visited and mapped. SeeSaw proposed to test the margins of the Stonefield and Brownlow granites with reconnaissance drilling. During licence year 2 of the project SeeSaw’s exploration activities included field exploration which involved structural mapping which was undertaken to identify potential economic mineralisation. Areas of recognised mineralisation were visited, mapped and rock chip sampled – with 17 samples collected from the Brownlow prospect and assayed for a comprehensive suite of metals and non-metals (full observation included within report but noted magnetite blebs & veins and pyrite grains). A small-scale ground magnetic survey was conducted, acquiring 39.5 line-km of ground magnetic data over pre-planned lines at Brownlow. Modelling of the ground magnetic data was limited by the design of the survey, position, azimuth, and strike length of source relied on airborne magnetic data. The ground magnetic data highlighted a probably miss-location of the airborne data over Brownlow. Exploration drilling program of three potential prospects located within EL5744 were conducted during April. The drilling comprised 6 drillhole for a total of 335.3m of Reverse Circulation (RC) drilling and 17m of Diamond Drilling (DD) resulting in 97 samples being submitted to ALS Laboratories for geochemical analysis. Regional drilling locations were selected to test for skarn geochemical dispersion and intrusive related Cu-Au mineralisation by targeting reactive host stratigraphy proximal to the Stonefield and Brownlow intrusives. The Brownlow drilling was planned to target potential Cu-Au skarn pathfinders along the western flank of the Brownlow intrusive body located in the central region of the Nackara Arc. Five holes were located along the north-south trending linear magnetic anomaly defined by the regional aerial magnetic and recent ground magnetic data. All holes penetrated various intensity parts of the magnetic anomaly, which is adequately explained by the occurrence of minor disseminated magnetite (1-3%) plus some narrow, semi-massive magnetite-quartz veins within Neoproterozoic Yerelina Subgroup and Saddleworth Formation metasediments. The metasediments are fissile aluminous lithologies (phyllite) that are largely unoxidised and show no alteration or mineralisation. The base of oxidation within them is interpreted to occur between ~15-20 m vertical depth (20-30 m downhole). Weak supergene gold enrichment (up to 8 ppb Au) occurs at this redox boundary, along with variable weak enrichments in base metals (0.5-1.2 ppm Bi, 50-115 ppm Cu, 5.5-7.5% Fe and 35-85 ppm Co). The Stonefield prospect was tested with a single Rotary mud hole with diamond tail, targeting reactive host stratigraphy proximal to the Stonefield intrusive. Hole SAW001 intersected basement at 97.3 m with a sharp erosional contact and limited weak – moderate weathering profile to fresh rock at 99.3 m. Basement lithology is an un-foliated, medium-coarse grained hornblende diorite (Ordovician), with strong dis-equilibrium crystallisation textures of variable size plagioclase and amphibole phenocrysts and porphyroblasts exhibiting reaction rims and alteration haloes. Minor magmatic crystallisation banding is observed, especially in mafic minerals. Alteration occurs as 10-40 cm patches (~25%) of chlorite +/- epidote +/- sericite +/- zeolite (pink adularia +/- Fe oxide), but no mineralisation is present. An alkaline igneous trace element geochemical signature (>500 ppm Ce, 14 ppm Hf, 216 ppm La, 46 ppm Th, 245 ppm Y and 494 ppm Zr) was seen in assay results from the downhole interval 103-104 m, but no discrete such lithology was discernible. No significant mineralisation was intersected. During licence year 3 of the project, exploration activities conducted included a desktop review that included establishing a GIS database and a review of historical exploration and available open file datasets. SeeSaw also continued its review of its drilling and structural field mapping data to identify potential economic mineralisation within the tenement. Reconnaissance field traverse were undertaken to determine the extent of magnetite veined and mineralised colluvium and stream float identified in the previous tears sampling program, confirming their presence proximal to the Brownlow prospect. However, no pyrites or base metal sulphides were observed associated with the float nor was any outcrop identified. Further reconnaissance traverses were conducted at the Brownlow Prospect to trace the source of gold mineralised colluvium and float of highly silicified, pyrite bearing metasediments or acid volcanics. Several additional rounded - sub-rounded silicified, pyritic pebbles were found in colluvial scree near the contact of the Appila Tillite with the underlying Neoproterozoic rocks. No outcrop or sub-crop of this style of gold mineralisation were observed and as such, the colluvium / float pebbles were interpreted to be derived from the basal tillites and so transported to the Brownlow prospect area by glaciation. During licence year 4 of the project, exploration activities conducted included: • Desktop review of historical exploration and available GIS datasets for the planning of exploration activities. • Reconnaissance traverses and target site inspection were undertaken to provide context for potential economic mineralisation within the tenement. The areas of reported mineralisation and exploration drilling by previous parties were visited, including inspecting drill core and drill chips held at Mines Department facilities. • Further reconnaissance to trace the source of gold mineralisation identified in the 2017/18 surface sampling program • Traverses on the western side of the tenement confirmed outcrops of pyritic, carbonaceous siltstones of the Cambrian Normanville Formation including the Nairne Pyrite Member. Tertiary weathering of this Formation may explain some elevated arsenic contents in weathered basement rocks to the east identified in coal and water well drilling databases. • Road cuttings were visited to familiarise geologists with lithologies. • The 2017 ground magnetic survey was reviewed and used to plan potential further geophysical surveys. • A review of previous metal and coal exploration in the area, with a particular focus on end-of-hole assays for redox-related secondary enrichment, to determine the potential for movement and concentration of As, Sb, Bi and other pathfinder elements potentially related to Cu-Au mineralisation. • Desktop review and geological interpretation of the aeromagnetic dataset for the Cambro-Ordovician Stonefield Granite, Black Hills Intrusive Suite and volcanoclastic pile including the Normanville Group and Kanmantoo Group. • Discussions with external mining companies and parties for potential Joint Venture partners. • Meetings with landowners regarding exploration access and multiple land use (renewable power). • Ongoing discussions with Energy Exploration regarding their Sedan coal exploration database and related coal test work. During licence year 5 of the project and the final reporting period for EL 5744, exploration activities included: • Further desktop review • Geological interpretation - Geological, lithostratigraphic and structural interpretation was revised for the aeromagnetic dataset for the Cambro-Ordovician Stonefield and Brownlow Granites, Black Hills Intrusive Suite and volcanoclastic pile including the Normanville Group and Kanmantoo Group. Structural interpretations were ground truthed. Interpretation work provided SeeSaw with a mineralisation model for the area. • Field reconnaissance traverses and target site visits to provide context for potential mineralisation and to support the mineralisation model: • Goethite +/- hematite and manganese veinlets (2 – 20 mm) identified in the Brighton Marble located adjacent to the Brownlow magnetic anomaly. • Cu +/- Ag, Fe in quartz breccia fault veins Proterozoic quartzite units adjacent to foliated metasiltstone ~6 km north of Dutton in the western half of the tenement. • Traced the Palmer Fault and related structures (minor mafic and felsic dykes). • Further discussions with potential JV partners and with landowners. During licence year 6 of the project and the first reporting period for renewed EL 6693, SeeSaw reported that exploration activities on the tenement were impacted by and limited due to government changes to the Mining Act. They believe it delayed the granting of the licence by up to 9 months and as such SeeSaw believed they were limited in their ability to recapitalise to support exploration as the licence was not legally theirs. Work was also limited due to restrictions brought in in response to the global COVID-19 pandemic, which limited the availability of contract geologists and exploration services. Work undertaken included: • Desktop reviews, analysis and interpretation of historical exploration information, research papers and available digital-GIS datasets were used in planning of exploration activities. • Geological reconnaissance trips to provide context for the mineralisation model. Sites visited included: • Quartz vein fault structures ~5km west of Brownlow. • Cambrian age Karinya pyrite unit and volcaniclastics ~2.5 km SE of Neales Flat/ • Ordovician age? Aplite dyke (with Fe Mn alteration and veining) ~500 m west of the Brownlow Trig. • Rathjen Gneiss, Palmer Granite and Mannum Granite (Ordovician age = Delamerian). During year 7 of the project for the second and final annual report for EL 6693, from 22nd February 2022 to the surrender of the licence on 8th March 2023, SeeSaw reported that exploration activities were severely impacted and limited due to the government’s decision to suspend Terramin Resources’ “Bird in Hand” mining application which was seen to significantly increase the sovereign risk of investment in exploration and mining development. As such the company was limited in corporate activity to attract funding for exploration. Due to investor and shareholder concern, SeeSaw Resources surrendered EL 6693 and withdrew from the ADI Grant exploration program. Exploration activities in the period were again limited to desktop reviews and reconnaissance site visits to provide context to mineralisation model. Site visits were made to the quartz vein fault structures west of Brownlow to determine fault/vein/intrusive kinetic indicators and support structural interpretation. Ordovician-age? aplite dyke samples from ~500 m west of the Brownlow Trig were provided for possible age dating within the Minex CRC Delamerian Project.