An assessment of the Late Tertiary Murray Basin shallow marine clastic sedimentary sequence (Loxton and Parilla sands) for heavy mineral sand accumulations has discovered numerous occurrences of economic to sub-economic amounts of heavy minerals...
An assessment of the Late Tertiary Murray Basin shallow marine clastic sedimentary sequence (Loxton and Parilla sands) for heavy mineral sand accumulations has discovered numerous occurrences of economic to sub-economic amounts of heavy minerals (ilmenite, rutile, zircon, leucoxene and monazite) within strandline mineral assemblages dominated by goethite. In the reporting period 19/12/1997 to 18/12/1998, during the first reporting period for the Steiner Holdings Pty Ltd – Murray Basins NL Joint Venture, exploration activities have included a review and interpretation of historical works a trial airborne magnetic/radiometric survey, aircore drilling and mineralogical work. This work has indicated that there is the potential to develop significant resources at the Mindarie prospect, and that follow-up drilling is warranted at the Mercunda, Champagne, Jezabeel and Long Tan prospects. Mineralogical work suggests fossil beach placer deposits in the Mindarie-Mercunda area contain an ilmenite-zircon dominated mineral suite. The airborne magnetic/radiometric survey was flown within EL 2439, with a total of 560 line-km flown with 100 m line spacing, and total field magnetics recorded every 5 m. No definitive magnetic response could be attribute to the heavy mineral concentrations of the Mindarie A and C lenses, however further processing of the data is ongoing. Three phases of aircore drilling were completed in the reporting period across the tenement group; 366 vertical holes for 6120 m were drilled on EL 2439 Mindarie Prospect (discovered by Aberfoyle Resources Ltd in 1986 and consisting of several lenses of mineralisation 100’s m wide), 133 holes for 2231 m were completed on EL 2448, and 2 holes for 45 m were completed on EL2477. Heavy liquid separation was completed on drilling samples, 5 samples were submitted for preliminary optical mineralogy by Mason while 7 magnetic fractions were processed and mounted as polished thin sections for further mineralogical work. All mineralogical examinations were completed by Mason Geoscience, with residues submitted to AMDEL for semi-quantitative mineralogy using XRD. During the second reporting period to 18/12/1999, 212 holes for 48,685 m of aircore drilling was completed, mineralogical investigations were undertaken along with bulk sample collection and assessment. Widespread heavy mineral sand mineralisation was intersected. A total of 112 drilling samples were submitted to Mason Geoscience for optical mineralogical investigations. Two traverses of HQ diameter aircore drilling were completed at the Mercunda prospect to collect a bulk sample for metallurgical evaluation. The estimation of resources for several prospects was started during the reporting period. The widespread occurrence of mineral sand strandline mineralisation in the project area is considered highly encouraging. Resource estimation and metallurgical investigation of the Mercunda prospect is in progress as a first stage investigation of the key economic parameters of mineral sand bodies in this portion of the Murray Basin. During the third reporting period to 18/12/2000, work completed on the project area saw the completion of an 1854-hole aircore drilling program for 33,339 m that was aimed at better refining and delineation of known resources and the discovery and delineation of new deposits within the Mindarie project area. Further mineralogical analysis of heavy mineral sand concentrates was conducted along with further metallurgical analysis of bulk samples from the Mercunda Deposit, and resource estimation and statistical analysis studies. Mineralogical work was completed by two consultants: Mason Geoscience and Roger Townend and Associates, optical mineralogy and X-ray florescence investigations were completed. Snowden’s Mining Industry Consultants were contracted to provide resource estimates for the nine prime deposits within the Mindarie Project area. During this reporting period, the Mindarie Project has advanced to the resource definition stage through extensive drilling of the prime deposits. The resource estimate has been increased by 320% and the mineralogical work has indicated a favourable, zircon-rich assemblage with a relatively low trash mineral content. During the fourth reporting period to 18/12/01, work on the JV project saw a 54,205 m aircore drilling program consisting of 2770 drillholes aimed the better definition and delineation of known heavy mineral sand deposits in the Mindarie Project area, the discovery and delineation of new heavy mineral sands deposits in the Mindarie Project area, and the upgrading of the prime deposits through close-spaced drilling to allow classification of reserve status under the JORC code. Further work across the project area saw the acquisition of aeromagnetic and radiometric data across the Mindarie project area (10,172 line-km – 400 m line spacing), triple tube coring of select holes, and mineralogical analysis of heavy mineral concentrate samples from several of the deposits in the project area, including 5 composite samples submitted to CSIRO for analysis utilising their QemScan method. Trials of downhole radiometric surveys were undertaken on the Mercunda, Mindarie and Amiens mineralisation zones to define the location, thickness and structure of the ores across 163 holes by Geoscience Associates Australia Pty Ltd. Data gained included total gamma count, long-spaced density, short-spaced density, neutron density and calliper logs. Processing of the aeromagnetic data highlighted several linear features parallel or subparallel to known mineral strands, however drill testing had mixed results, where the strongest features did not necessarily correspond to the higher-grade strands. It was found that the effects of iron oxide minerals within the overburden and mineralised sand seems to mask the response from ilmenite-rich mineralisation in many cases, and the relationship between the aeromagnetic data and known mineralisation is somewhat tenuous. The final feasibility study for the Mindarie Project was progressing during the reporting period, with completion expected in mid-2002. Exploration licence 2438, 2448, 2512 and 2519 all underwent partial relinquishments during the reporting period. During the fifth reporting period to 18th December 2002, Steiner Holdings Pty Ltd became fully owned by Southern Titanium NL as of January 2002. Exploration work completed in the period included an aircore drilling program of 47,880 m from 1830 holes, the extensive use of down hole radiometric surveys (236 holes) to define the location, thickness and structure of the ore zones on the Mercunda, Mindarie A, Mindarie C, Amiens and Balmoral deposits and in some regional exploration areas. Mineralogical work continued with heavy mineral samples from across the project, plus metallurgical analysis from bulk samples from the newly defined Derrick deposit. During the reporting period the pegging of Mineral Claims and Mining Licence applications (granted) over three of the deposits (Mercunda, Lone Pine and Mindarie A2) and the commencement of Compensation Agreement negotiations with the affected Landholders was undertaken. Exploration licences 2746, 2747 and 2805 all underwent partial relinquishments during the reporting period. During the sixth reporting period to 18th December 2003, work completed during the reporting period was almost entirely focused on the Bankable Feasibility Study and towards the gaining of finance for a mining project. A total of 42 Mineral claims were pegged and Mining Lease Applications lodged over these claims to cover the Amiens, Halidon, Long Tan, Mindarie C and Mindarie A1 strandlines. Two costeans were dug, one each on Mindarie A1 and Mindarie C, to gain bulk samples for mineralogical and metallurgical analysis. A series of 64 raw drill samples from the Loxton area and the Derrick deposit were sent to Geoscience Australia for Laser Grainsize Analysis. Geoscience Australia conducted traverses of Electro-Kinetic Sounding along several drill traverses. This then allowed direct correlation of the EKS with known geology and hydrology, further refined with the grain sizing of selected samples from selected drillholes. Exploration licences 3042, 2746 and 2873 underwent partial relinquishments during the reporting period, while EL’s 2747 and 2805 were fully relinquished as of 23/6/2003. During reporting periods seven through nine to 18th December 2006, work included the completion of 2 aircore drilling programs, the first in 2005 involving infill and extensional drilling on the Lone Pine North, Mindarie A2, Mindarie C, Amiens and Halidon deposits (880 holes for 17,124 m) and the second in 2006 involving close-spaced grade control drilling at Mindarie A2 (564 holes for 9120 m). The purpose of the 2005 infill aircore drilling program was to provide an adequate density of drilling to enable a conversion of potential in-pit resources from the Indicated Resource to the Measured Resource status in these under-drilled areas. Resource estimation studies were undertaken, and an additional Mineral Claim was pegged (MC 3495) over the eastern end of the Mercunda North deposit. A further 3 costeans were dug and rehabilitated on the Mindarie A1, Mercunda North and Lone Pine North deposits to gain additional bulk samples for mineralogical and metallurgical testing, plus an additional 3 on the Mindarie A2 deposit. Work continued towards the completion of the Final/Bankable Feasibility studies, plus the preparation of a Mining and Rehabilitation Program (MARP) for Mindarie A2. In January 2005, a 12% relinquishment was made which included the full relinquishment of EL 2746, EL 2826, EL 2873 and EL 3051 and partial relinquishments of EL 3042 and EL 3103. In January 2006 a further 10% reduction was made, based on the partial relinquishment of the majority of ground held under EL 2857. During the tenth reporting period to 31st December 2007, work included resource evaluation studies including block modelling, mineralogical investigation, gamma data evaluation, database upgrading, grade control evaluation and resource / grade control model reconciliations. Studies were undertaken in pit optimisation and design, and the exploration database underwent validation. Analytical drill core data from the previous reporting period was included in this year’s reporting period. The granting of all outstanding statutory licensing and permitting requirements during the year has led to the successful construction and commissioning of the Mindarie Zircon Project. Processing of the infill aircore drilling data at Mindarie A2 has enabled extensive orebody modelling and pit optimisation work to be undertaken which has facilitated the commencement of mining late in the year. In February 2007 the Company relinquished an area of 1,016 km², representing approximately 8% of the total area held under its Amalgamated Expenditure Agreement. This included most of the remaining area held under EL 3569 (Renmark), a substantial part of EL 3090 (Loxton) and lesser parts of EL 3103 (Meribah), EL 3568 (Woolpunda) and EL 3046 (Mantung – ELA 07/00452). During the year, Australian Zircon NL entered an arrangement with Goldfields Australasia Pty Ltd (‘GFA’) allowing GFA to evaluate basement for potential gold mineralisation within several tenements subject of the AEA. (Data supplied in Goldfields Australia EL3624 "Delamarian Project") [ENV11448 CNO:2038430]. Work during 2007 included data evaluation and regional assessment to generate basement targets for drill testing during 2008. A regional helicopter-assisted gravity survey was undertaken throughout EL 3627 (503 gravity stations) and in the north and central western parts of EL 3539 (320 gravity stations). A trial of SkyTEM airborne electromagnetic surveying was also carried out on adjoining tenements by GFA with several traverses conducted over EL 3627 (65-line km) and EL 3539 (4-line km). Results from the SkyTEM survey confirmed that the Tertiary Murray Basin sediments were not to deep in the area to preclude basement drilling while the gravity data further assisted in the definition of structural targets for follow-up drilling. During the eleventh reporting period to 31st December 2008, work has comprised of infill aircore drilling programs on the Mindarie C and Mindarie A2 resources, and resource and reserve estimations for the Mindarie Project. Resource evaluation studies and pit optimisation studies were continued, and a Mining and Rehabilitation Program (MARP) was prepared for the Mindarie C mining lease. Further drilling programs in the project area included a reconnaissance aircore drilling program northeast of Morgan on the Morgan EL 4180, and a deep reconnaissance aircore drilling on ELs 3539 and 3627 as part of basement gold exploration program conducted by Goldfields Australasia JV. In July 2008 the Company relinquished approximately 3% of the total area held under its Amalgamated Expenditure Agreement. This included parts of EL 3568 (Woolpunda), EL 3569 (Renmark), EL 3082 (Morgan), EL 3090 (Loxton), EL 3103 (Meribah), EL 4017 (Halidon, previously EL 3041) and EL 4018 (Mantung, previously EL 3046). The infill drilling program was undertaken on the central portion of the Mindarie C deposit, a total of 638 holes were drilled for 9854 m, with further infill drilling completed along a 3 km section of the Mindarie A2 deposit with 350 holes drilled for 510 m. All holes underwent downhole gamma logging and sample analysis was completed based on visual estimations of >1% heavy minerals. The drilling has provided improved definition of resource boundaries and enabled accurate evaluation of recoverable reserves and optimised pit designs. The reconnaissance drilling program on EL 4180 saw 100 holes drilled for a total of 2203 m. No significant occurrences of heavy mineral sands were encountered in the drilling. The highest estimated value was 0.2% HM. Several conceptual targets failed to encounter any significant evidence of heavy mineral sand deposition. This area is recommended for relinquishment. The deep aircore drilling program completed by JV partners Goldfields Australasia saw 14 holes drilled 2453 m, with 133 samples submitted for multi-element geochemical analysis. The program aimed to test structural basement targets thought prospective for gold. Of the 14 holes drilled, 8 successfully penetrated cover sequences and intersected Palaeozoic Kanmantoo basement at depths of approximately 200 – 230 m. During the twelfth reporting period to 31st December 2009, in early October Australian Zircon NL was placed into voluntary administration and exploration activities were suspended. Prior to this, the drilling of 539 aircore holes had been completed, comprising 21,791.5 m. A total of 1359 samples were assayed; no mineralogical determinations were completed. The aim of the drilling was to investigate aeromagnetic targets, the poorly drilled region immediately north of mining operations and the possibility of undiscovered shoal mineralisation associated with known deposits. During the thirteenth reporting period to 31st December 2010, Australian Zircon NL and Steiner Holdings Pty Ltd were in voluntary administration for much of the 2010 calendar year. Consequently, no exploration field work was conducted on the tenements.