Commonwealth Hill Station - Central (part of the Commonwealth Hill Project). Second partial surrender report, for the period 11/5/2007 to 10/5/2017.
Published: 04 Dec 1917 Created: 12 Nov 2024 Revised: 12 Nov 2024

Six separate portions of the subject licence, with a combined total area of 35 square km, have been surrendered due to their now perceived diminished prospectivity for iron ore, gold, uranium, PGEs and base metals. During the period of their...

Six separate portions of the subject licence, with a combined total area of 35 square km, have been surrendered due to their now perceived diminished prospectivity for iron ore, gold, uranium, PGEs and base metals. During the period of their tenure, exploration attention was directed primarily at possible buried IOCG and other style base metal sulphide targets that may have formed within the basement, as well as any economic primary gold mineralisation. Work that was completed by Apollo Minerals on the now surrendered portions of EL 5073 included: - soil calcrete (365 samples) and bedrock outcrop (14 rock chip grab samples) geochemical sampling; - acquisition of parts of a ground-based gravity survey and of a gradient array IP survey; - acquisition of moving loop and fixed loop TEM profiles over gravity anomaly targets; and - exploratory diamond drilling at the Acacia East and Acacia prospects, with downhole TEM surveys subsequently run in the three new drillholes. 135 calcrete samples were collected across a 200 m x 200 m grid at Acacia prospect, and 230 calcrete samples were collected across a 100 m x 100 m grid at Acacia East Prospect. The samples were analysed for a whole rock suite and 38 individual elements. The assay values returned at Acacia East defined an anomalous surface geochemical halo for Cu, Au, Co, Ni, Ag and Pt, which are all typical pathfinder elements to IOCG style mineralisation. The rock chip grab samples obtained from very sparse bedrock outcrops found within the surrendered licence portions were sent off for whole rock chemical analysis. During September 2012 and January 2013, subsets of two gravity surveys were read over the Acacia and Acacia East prospects at various grid spacings (the total coverage being 1464 stations on Acacia, and 1430 stations on Acacia East). The Acacia East 75 m x 75 m gravity data delineated a large residual anomaly measuring +2.3 mGal in amplitude and covering 4.2 km x 1.6 km, which correlates with a discrete magnetic low that is situated adjacent to the regional scale Coorabie Fault Zone. Therefore additional geophysical work was done at this prospect, comprising 197.3 line km of ground-based moving loop and 2 line km of ground-based fixed loop TEM profiles acquired later in 2013, plus parts of a gradient array IP survey read during April-May 2014 along north-south lines spaced 400 m apart. The moving loop TEM data indicated that there are large, high-strength conductors in the bedrock at Acacia East, with the 1000 Siemens GS01 conductor extending for 1200 m along strike and 800 m across strike, and having an apparent vertical extent of >1500 m. Apollo Minerals thought that this level of EM response could come from a massive sulphide body perhaps containing significant Ni-Cu-PGE or IOCGU type mineralisation. It appeared to coincide with a discrete demagnetised zone that cross-cuts older magnetic stratigraphy, suggesting the presence of either a younger igneous intrusion or late stage hydrothermal alteration. During March-April 2013, three inclined fully diamond HQ/NQ2 cored holes were drilled at Acacia East, for a total penetration of 1286 m. They encountered basement felsic, intermediate and mafic rocks units, the latter including amphibolite, diorite and gabbroic gneisses. A metamorphosed quartz-feldspar-biotite-magnetite±garnet granite unit in the core displays high levels of potassic alteration. The drilling intersected many intervals of disseminated stringer and massive sulphides, mainly consisting of uneconomic pyrrhotite and pyrite species. Hole ACEDD001 was terminated at an end-of-hole (EOH) depth of 420.8 m, having been aimed at a high strength EM target that was modelled at 220 m vertical depth. Sulphides were interested from ~210 m and continued downhole for 95 discontinuous metres. A massive sulphide intercept was made at 329 m hole depth, which yielded assays of 8 m @ 710 ppm Cu, 0.01 g/t Au, 0.9 g/t Ag, 293 ppm Ni and 109 ppm Co from 327-335 m, plus 1 m @ 215 ppm Ni, 0.1 g/t Au and 80 ppm Co from 354-355 m. Hole ACEDD002 was terminated at an EOH depth of 282.5 m, having been aimed at a localised gravity high situated adjacent to the GS01 conductive EM anomaly. Bornite mineralisation was encountered at 29 m, followed by disseminated and stringer sulphides of primarily pyrrhotite and pyrite with lesser amounts of chalcopyrite, these all occurring within magnetite-altered amphibolite and gneissic rock units. Hole ACEDD003 was terminated at an EOH depth of 582.7 m, and was designed to test the alteration of rock units at depth below the conductive EM target. It intersected disseminated and stringer sulphides, mainly pyrrhotite and pyrite, within amphibolite, diorite and gabbroic gneisses. At downhole depths below 500 m, much coarser-grained and more sodic-altered anorthosite units were encountered, indicative of alteration and magmatic differentiation in the mafic igneous units. Best drill core sample assay results were 128 m @ 105 ppm Ni and 20 ppm Co from 380-508 m, including 8 m @ 345 ppm Cu, 95 ppm Ni and 48 ppm Co from 480-488 m. Following the completion of diamond drilling, downhole TEM surveys were conducted in the now PVC cased holes ACEDD001 and 003 (involving 66 readings over 410 m, and 56 readings over 550 m, respectively). Apollo Minerals concluded that the observed pervasive hydrothermal alteration, magnetite destruction and sulphide mineralisation in the Acacia East drill cores show that its initial round of drilling had intersected a significant, probably distal to marginal part of a large-scale, possibly IOCG type mineral system, thus giving much encouragement for additional exploration adjacent to the prospect area. During April-May 2014, parts of a gradient array IP survey were read along north-south lines spaced 400 m apart by private company farminee High Power Exploration, Inc. That newly formed, Canadian-based company had entered the Commonwealth Hill Project to explore for IOCG mineralisation and other economic minerals, primarily by using its proprietary electrical surveying methods to identify targets which might otherwise be indiscernible using conventional IP survey methods.

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About this record

Record No mesac27745
Topic Geoscientific Information
Type of Resource Document
Category Type
Document Type Mineral Company Report - Mineral Exploration
Contributor Apollo Minerals Limited;Daishsat Geodetic Surveyors;GEM Geophysical Surveys Pty Ltd
Sponsor Apollo Minerals Limited
Tenement
Tenement Holder Southern Exploration Pty Ltd;High Power Exploration, Inc.
Operator Apollo Minerals Limited;High Power Exploration, Inc.
Geological Province
Mine Name Acacia East prospect;Acacia prospect
Stratigraphy Mulgathing Complex
Commodity
Notes
Notes: A farm-in agreement was in force between Apollo Minerals and High Power Exploration, Inc. (HPX) over the period 15/5/2014 to 21/8/2015, with HPX operating the Commonwealth Hill Project exploration programme during that period, when it spent...

Notes: A farm-in agreement was in force between Apollo Minerals and High Power Exploration, Inc. (HPX) over the period 15/5/2014 to 21/8/2015, with HPX operating the Commonwealth Hill Project exploration programme during that period, when it spent over $1.1 million on work comprising >140 square km of high powered IP surveys, which identified multiple targets, and the drilling of five partially cored RC holes for 870 m. Geographic Locality: Commonwealth Hill Station;Woomera Prohibited Area;2011 Commonwealth Hill II Gravity Survey [part];2013 Commonwealth Hill III Gravity Survey [part] Doc No: Env 11574 Drillhole: ACEDD001;(285456);ACEDD002;(285472);ACEDD003;(285457)

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Language English
Metadata Standard ISO 19115-3

Citations

Use constraints License
License Creative Commons Attribution 4.0
Persistent identifier https://pid.sarig.sa.gov.au/document/mesac27745
Citation Hodgins, J. 1917. Commonwealth Hill Station - Central (part of the Commonwealth Hill Project). Second partial surrender report, for the period 11/5/2007 to 10/5/2017. Mineral Company Report - Mineral Exploration
https://pid.sarig.sa.gov.au/document/mesac27745

Technical information

Status
Maintenance and Update Frequency
Geographic Reference GDA2020 (EPSG:7844)
Geo bounding box {"type":"Polygon","coordinates":[[[133.5,-30],[134.5,-30],[134.5,-29.5],[133.5,-29.5],[133.5,-30]]]}
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Lineage